xref: /llvm-project/clang/lib/CodeGen/CodeGenModule.cpp (revision aa2741449c3609b2ae244d8d3f3e14ad16de72e4)
1 //===--- CodeGenModule.cpp - Emit LLVM Code from ASTs for a Module --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This coordinates the per-module state used while generating code.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CodeGenModule.h"
14 #include "ABIInfo.h"
15 #include "CGBlocks.h"
16 #include "CGCUDARuntime.h"
17 #include "CGCXXABI.h"
18 #include "CGCall.h"
19 #include "CGDebugInfo.h"
20 #include "CGHLSLRuntime.h"
21 #include "CGObjCRuntime.h"
22 #include "CGOpenCLRuntime.h"
23 #include "CGOpenMPRuntime.h"
24 #include "CGOpenMPRuntimeGPU.h"
25 #include "CodeGenFunction.h"
26 #include "CodeGenPGO.h"
27 #include "ConstantEmitter.h"
28 #include "CoverageMappingGen.h"
29 #include "TargetInfo.h"
30 #include "clang/AST/ASTContext.h"
31 #include "clang/AST/ASTLambda.h"
32 #include "clang/AST/CharUnits.h"
33 #include "clang/AST/Decl.h"
34 #include "clang/AST/DeclCXX.h"
35 #include "clang/AST/DeclObjC.h"
36 #include "clang/AST/DeclTemplate.h"
37 #include "clang/AST/Mangle.h"
38 #include "clang/AST/RecursiveASTVisitor.h"
39 #include "clang/AST/StmtVisitor.h"
40 #include "clang/Basic/Builtins.h"
41 #include "clang/Basic/CharInfo.h"
42 #include "clang/Basic/CodeGenOptions.h"
43 #include "clang/Basic/Diagnostic.h"
44 #include "clang/Basic/FileManager.h"
45 #include "clang/Basic/Module.h"
46 #include "clang/Basic/SourceManager.h"
47 #include "clang/Basic/TargetInfo.h"
48 #include "clang/Basic/Version.h"
49 #include "clang/CodeGen/BackendUtil.h"
50 #include "clang/CodeGen/ConstantInitBuilder.h"
51 #include "clang/Frontend/FrontendDiagnostic.h"
52 #include "llvm/ADT/STLExtras.h"
53 #include "llvm/ADT/StringExtras.h"
54 #include "llvm/ADT/StringSwitch.h"
55 #include "llvm/Analysis/TargetLibraryInfo.h"
56 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
57 #include "llvm/IR/AttributeMask.h"
58 #include "llvm/IR/CallingConv.h"
59 #include "llvm/IR/DataLayout.h"
60 #include "llvm/IR/Intrinsics.h"
61 #include "llvm/IR/LLVMContext.h"
62 #include "llvm/IR/Module.h"
63 #include "llvm/IR/ProfileSummary.h"
64 #include "llvm/ProfileData/InstrProfReader.h"
65 #include "llvm/ProfileData/SampleProf.h"
66 #include "llvm/Support/CRC.h"
67 #include "llvm/Support/CodeGen.h"
68 #include "llvm/Support/CommandLine.h"
69 #include "llvm/Support/ConvertUTF.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/RISCVISAInfo.h"
72 #include "llvm/Support/TimeProfiler.h"
73 #include "llvm/Support/xxhash.h"
74 #include "llvm/TargetParser/Triple.h"
75 #include "llvm/TargetParser/X86TargetParser.h"
76 #include <optional>
77 
78 using namespace clang;
79 using namespace CodeGen;
80 
81 static llvm::cl::opt<bool> LimitedCoverage(
82     "limited-coverage-experimental", llvm::cl::Hidden,
83     llvm::cl::desc("Emit limited coverage mapping information (experimental)"));
84 
85 static const char AnnotationSection[] = "llvm.metadata";
86 
87 static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
88   switch (CGM.getContext().getCXXABIKind()) {
89   case TargetCXXABI::AppleARM64:
90   case TargetCXXABI::Fuchsia:
91   case TargetCXXABI::GenericAArch64:
92   case TargetCXXABI::GenericARM:
93   case TargetCXXABI::iOS:
94   case TargetCXXABI::WatchOS:
95   case TargetCXXABI::GenericMIPS:
96   case TargetCXXABI::GenericItanium:
97   case TargetCXXABI::WebAssembly:
98   case TargetCXXABI::XL:
99     return CreateItaniumCXXABI(CGM);
100   case TargetCXXABI::Microsoft:
101     return CreateMicrosoftCXXABI(CGM);
102   }
103 
104   llvm_unreachable("invalid C++ ABI kind");
105 }
106 
107 static std::unique_ptr<TargetCodeGenInfo>
108 createTargetCodeGenInfo(CodeGenModule &CGM) {
109   const TargetInfo &Target = CGM.getTarget();
110   const llvm::Triple &Triple = Target.getTriple();
111   const CodeGenOptions &CodeGenOpts = CGM.getCodeGenOpts();
112 
113   switch (Triple.getArch()) {
114   default:
115     return createDefaultTargetCodeGenInfo(CGM);
116 
117   case llvm::Triple::le32:
118     return createPNaClTargetCodeGenInfo(CGM);
119   case llvm::Triple::m68k:
120     return createM68kTargetCodeGenInfo(CGM);
121   case llvm::Triple::mips:
122   case llvm::Triple::mipsel:
123     if (Triple.getOS() == llvm::Triple::NaCl)
124       return createPNaClTargetCodeGenInfo(CGM);
125     return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/true);
126 
127   case llvm::Triple::mips64:
128   case llvm::Triple::mips64el:
129     return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/false);
130 
131   case llvm::Triple::avr: {
132     // For passing parameters, R8~R25 are used on avr, and R18~R25 are used
133     // on avrtiny. For passing return value, R18~R25 are used on avr, and
134     // R22~R25 are used on avrtiny.
135     unsigned NPR = Target.getABI() == "avrtiny" ? 6 : 18;
136     unsigned NRR = Target.getABI() == "avrtiny" ? 4 : 8;
137     return createAVRTargetCodeGenInfo(CGM, NPR, NRR);
138   }
139 
140   case llvm::Triple::aarch64:
141   case llvm::Triple::aarch64_32:
142   case llvm::Triple::aarch64_be: {
143     AArch64ABIKind Kind = AArch64ABIKind::AAPCS;
144     if (Target.getABI() == "darwinpcs")
145       Kind = AArch64ABIKind::DarwinPCS;
146     else if (Triple.isOSWindows())
147       return createWindowsAArch64TargetCodeGenInfo(CGM, AArch64ABIKind::Win64);
148     else if (Target.getABI() == "aapcs-soft")
149       Kind = AArch64ABIKind::AAPCSSoft;
150 
151     return createAArch64TargetCodeGenInfo(CGM, Kind);
152   }
153 
154   case llvm::Triple::wasm32:
155   case llvm::Triple::wasm64: {
156     WebAssemblyABIKind Kind = WebAssemblyABIKind::MVP;
157     if (Target.getABI() == "experimental-mv")
158       Kind = WebAssemblyABIKind::ExperimentalMV;
159     return createWebAssemblyTargetCodeGenInfo(CGM, Kind);
160   }
161 
162   case llvm::Triple::arm:
163   case llvm::Triple::armeb:
164   case llvm::Triple::thumb:
165   case llvm::Triple::thumbeb: {
166     if (Triple.getOS() == llvm::Triple::Win32)
167       return createWindowsARMTargetCodeGenInfo(CGM, ARMABIKind::AAPCS_VFP);
168 
169     ARMABIKind Kind = ARMABIKind::AAPCS;
170     StringRef ABIStr = Target.getABI();
171     if (ABIStr == "apcs-gnu")
172       Kind = ARMABIKind::APCS;
173     else if (ABIStr == "aapcs16")
174       Kind = ARMABIKind::AAPCS16_VFP;
175     else if (CodeGenOpts.FloatABI == "hard" ||
176              (CodeGenOpts.FloatABI != "soft" &&
177               (Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
178                Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
179                Triple.getEnvironment() == llvm::Triple::EABIHF)))
180       Kind = ARMABIKind::AAPCS_VFP;
181 
182     return createARMTargetCodeGenInfo(CGM, Kind);
183   }
184 
185   case llvm::Triple::ppc: {
186     if (Triple.isOSAIX())
187       return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/false);
188 
189     bool IsSoftFloat =
190         CodeGenOpts.FloatABI == "soft" || Target.hasFeature("spe");
191     return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
192   }
193   case llvm::Triple::ppcle: {
194     bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
195     return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
196   }
197   case llvm::Triple::ppc64:
198     if (Triple.isOSAIX())
199       return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/true);
200 
201     if (Triple.isOSBinFormatELF()) {
202       PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv1;
203       if (Target.getABI() == "elfv2")
204         Kind = PPC64_SVR4_ABIKind::ELFv2;
205       bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
206 
207       return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
208     }
209     return createPPC64TargetCodeGenInfo(CGM);
210   case llvm::Triple::ppc64le: {
211     assert(Triple.isOSBinFormatELF() && "PPC64 LE non-ELF not supported!");
212     PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv2;
213     if (Target.getABI() == "elfv1")
214       Kind = PPC64_SVR4_ABIKind::ELFv1;
215     bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
216 
217     return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
218   }
219 
220   case llvm::Triple::nvptx:
221   case llvm::Triple::nvptx64:
222     return createNVPTXTargetCodeGenInfo(CGM);
223 
224   case llvm::Triple::msp430:
225     return createMSP430TargetCodeGenInfo(CGM);
226 
227   case llvm::Triple::riscv32:
228   case llvm::Triple::riscv64: {
229     StringRef ABIStr = Target.getABI();
230     unsigned XLen = Target.getPointerWidth(LangAS::Default);
231     unsigned ABIFLen = 0;
232     if (ABIStr.ends_with("f"))
233       ABIFLen = 32;
234     else if (ABIStr.ends_with("d"))
235       ABIFLen = 64;
236     bool EABI = ABIStr.ends_with("e");
237     return createRISCVTargetCodeGenInfo(CGM, XLen, ABIFLen, EABI);
238   }
239 
240   case llvm::Triple::systemz: {
241     bool SoftFloat = CodeGenOpts.FloatABI == "soft";
242     bool HasVector = !SoftFloat && Target.getABI() == "vector";
243     return createSystemZTargetCodeGenInfo(CGM, HasVector, SoftFloat);
244   }
245 
246   case llvm::Triple::tce:
247   case llvm::Triple::tcele:
248     return createTCETargetCodeGenInfo(CGM);
249 
250   case llvm::Triple::x86: {
251     bool IsDarwinVectorABI = Triple.isOSDarwin();
252     bool IsWin32FloatStructABI = Triple.isOSWindows() && !Triple.isOSCygMing();
253 
254     if (Triple.getOS() == llvm::Triple::Win32) {
255       return createWinX86_32TargetCodeGenInfo(
256           CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
257           CodeGenOpts.NumRegisterParameters);
258     }
259     return createX86_32TargetCodeGenInfo(
260         CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
261         CodeGenOpts.NumRegisterParameters, CodeGenOpts.FloatABI == "soft");
262   }
263 
264   case llvm::Triple::x86_64: {
265     StringRef ABI = Target.getABI();
266     X86AVXABILevel AVXLevel = (ABI == "avx512" ? X86AVXABILevel::AVX512
267                                : ABI == "avx"  ? X86AVXABILevel::AVX
268                                                : X86AVXABILevel::None);
269 
270     switch (Triple.getOS()) {
271     case llvm::Triple::Win32:
272       return createWinX86_64TargetCodeGenInfo(CGM, AVXLevel);
273     default:
274       return createX86_64TargetCodeGenInfo(CGM, AVXLevel);
275     }
276   }
277   case llvm::Triple::hexagon:
278     return createHexagonTargetCodeGenInfo(CGM);
279   case llvm::Triple::lanai:
280     return createLanaiTargetCodeGenInfo(CGM);
281   case llvm::Triple::r600:
282     return createAMDGPUTargetCodeGenInfo(CGM);
283   case llvm::Triple::amdgcn:
284     return createAMDGPUTargetCodeGenInfo(CGM);
285   case llvm::Triple::sparc:
286     return createSparcV8TargetCodeGenInfo(CGM);
287   case llvm::Triple::sparcv9:
288     return createSparcV9TargetCodeGenInfo(CGM);
289   case llvm::Triple::xcore:
290     return createXCoreTargetCodeGenInfo(CGM);
291   case llvm::Triple::arc:
292     return createARCTargetCodeGenInfo(CGM);
293   case llvm::Triple::spir:
294   case llvm::Triple::spir64:
295     return createCommonSPIRTargetCodeGenInfo(CGM);
296   case llvm::Triple::spirv32:
297   case llvm::Triple::spirv64:
298     return createSPIRVTargetCodeGenInfo(CGM);
299   case llvm::Triple::ve:
300     return createVETargetCodeGenInfo(CGM);
301   case llvm::Triple::csky: {
302     bool IsSoftFloat = !Target.hasFeature("hard-float-abi");
303     bool hasFP64 =
304         Target.hasFeature("fpuv2_df") || Target.hasFeature("fpuv3_df");
305     return createCSKYTargetCodeGenInfo(CGM, IsSoftFloat ? 0
306                                             : hasFP64   ? 64
307                                                         : 32);
308   }
309   case llvm::Triple::bpfeb:
310   case llvm::Triple::bpfel:
311     return createBPFTargetCodeGenInfo(CGM);
312   case llvm::Triple::loongarch32:
313   case llvm::Triple::loongarch64: {
314     StringRef ABIStr = Target.getABI();
315     unsigned ABIFRLen = 0;
316     if (ABIStr.ends_with("f"))
317       ABIFRLen = 32;
318     else if (ABIStr.ends_with("d"))
319       ABIFRLen = 64;
320     return createLoongArchTargetCodeGenInfo(
321         CGM, Target.getPointerWidth(LangAS::Default), ABIFRLen);
322   }
323   }
324 }
325 
326 const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
327   if (!TheTargetCodeGenInfo)
328     TheTargetCodeGenInfo = createTargetCodeGenInfo(*this);
329   return *TheTargetCodeGenInfo;
330 }
331 
332 CodeGenModule::CodeGenModule(ASTContext &C,
333                              IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
334                              const HeaderSearchOptions &HSO,
335                              const PreprocessorOptions &PPO,
336                              const CodeGenOptions &CGO, llvm::Module &M,
337                              DiagnosticsEngine &diags,
338                              CoverageSourceInfo *CoverageInfo)
339     : Context(C), LangOpts(C.getLangOpts()), FS(FS), HeaderSearchOpts(HSO),
340       PreprocessorOpts(PPO), CodeGenOpts(CGO), TheModule(M), Diags(diags),
341       Target(C.getTargetInfo()), ABI(createCXXABI(*this)),
342       VMContext(M.getContext()), Types(*this), VTables(*this),
343       SanitizerMD(new SanitizerMetadata(*this)) {
344 
345   // Initialize the type cache.
346   llvm::LLVMContext &LLVMContext = M.getContext();
347   VoidTy = llvm::Type::getVoidTy(LLVMContext);
348   Int8Ty = llvm::Type::getInt8Ty(LLVMContext);
349   Int16Ty = llvm::Type::getInt16Ty(LLVMContext);
350   Int32Ty = llvm::Type::getInt32Ty(LLVMContext);
351   Int64Ty = llvm::Type::getInt64Ty(LLVMContext);
352   HalfTy = llvm::Type::getHalfTy(LLVMContext);
353   BFloatTy = llvm::Type::getBFloatTy(LLVMContext);
354   FloatTy = llvm::Type::getFloatTy(LLVMContext);
355   DoubleTy = llvm::Type::getDoubleTy(LLVMContext);
356   PointerWidthInBits = C.getTargetInfo().getPointerWidth(LangAS::Default);
357   PointerAlignInBytes =
358       C.toCharUnitsFromBits(C.getTargetInfo().getPointerAlign(LangAS::Default))
359           .getQuantity();
360   SizeSizeInBytes =
361     C.toCharUnitsFromBits(C.getTargetInfo().getMaxPointerWidth()).getQuantity();
362   IntAlignInBytes =
363     C.toCharUnitsFromBits(C.getTargetInfo().getIntAlign()).getQuantity();
364   CharTy =
365     llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getCharWidth());
366   IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
367   IntPtrTy = llvm::IntegerType::get(LLVMContext,
368     C.getTargetInfo().getMaxPointerWidth());
369   Int8PtrTy = llvm::PointerType::get(LLVMContext, 0);
370   const llvm::DataLayout &DL = M.getDataLayout();
371   AllocaInt8PtrTy =
372       llvm::PointerType::get(LLVMContext, DL.getAllocaAddrSpace());
373   GlobalsInt8PtrTy =
374       llvm::PointerType::get(LLVMContext, DL.getDefaultGlobalsAddressSpace());
375   ConstGlobalsPtrTy = llvm::PointerType::get(
376       LLVMContext, C.getTargetAddressSpace(GetGlobalConstantAddressSpace()));
377   ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
378 
379   // Build C++20 Module initializers.
380   // TODO: Add Microsoft here once we know the mangling required for the
381   // initializers.
382   CXX20ModuleInits =
383       LangOpts.CPlusPlusModules && getCXXABI().getMangleContext().getKind() ==
384                                        ItaniumMangleContext::MK_Itanium;
385 
386   RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC();
387 
388   if (LangOpts.ObjC)
389     createObjCRuntime();
390   if (LangOpts.OpenCL)
391     createOpenCLRuntime();
392   if (LangOpts.OpenMP)
393     createOpenMPRuntime();
394   if (LangOpts.CUDA)
395     createCUDARuntime();
396   if (LangOpts.HLSL)
397     createHLSLRuntime();
398 
399   // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0.
400   if (LangOpts.Sanitize.has(SanitizerKind::Thread) ||
401       (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0))
402     TBAA.reset(new CodeGenTBAA(Context, getTypes(), TheModule, CodeGenOpts,
403                                getLangOpts(), getCXXABI().getMangleContext()));
404 
405   // If debug info or coverage generation is enabled, create the CGDebugInfo
406   // object.
407   if (CodeGenOpts.getDebugInfo() != llvm::codegenoptions::NoDebugInfo ||
408       CodeGenOpts.CoverageNotesFile.size() ||
409       CodeGenOpts.CoverageDataFile.size())
410     DebugInfo.reset(new CGDebugInfo(*this));
411 
412   Block.GlobalUniqueCount = 0;
413 
414   if (C.getLangOpts().ObjC)
415     ObjCData.reset(new ObjCEntrypoints());
416 
417   if (CodeGenOpts.hasProfileClangUse()) {
418     auto ReaderOrErr = llvm::IndexedInstrProfReader::create(
419         CodeGenOpts.ProfileInstrumentUsePath, *FS,
420         CodeGenOpts.ProfileRemappingFile);
421     // We're checking for profile read errors in CompilerInvocation, so if
422     // there was an error it should've already been caught. If it hasn't been
423     // somehow, trip an assertion.
424     assert(ReaderOrErr);
425     PGOReader = std::move(ReaderOrErr.get());
426   }
427 
428   // If coverage mapping generation is enabled, create the
429   // CoverageMappingModuleGen object.
430   if (CodeGenOpts.CoverageMapping)
431     CoverageMapping.reset(new CoverageMappingModuleGen(*this, *CoverageInfo));
432 
433   // Generate the module name hash here if needed.
434   if (CodeGenOpts.UniqueInternalLinkageNames &&
435       !getModule().getSourceFileName().empty()) {
436     std::string Path = getModule().getSourceFileName();
437     // Check if a path substitution is needed from the MacroPrefixMap.
438     for (const auto &Entry : LangOpts.MacroPrefixMap)
439       if (Path.rfind(Entry.first, 0) != std::string::npos) {
440         Path = Entry.second + Path.substr(Entry.first.size());
441         break;
442       }
443     ModuleNameHash = llvm::getUniqueInternalLinkagePostfix(Path);
444   }
445 }
446 
447 CodeGenModule::~CodeGenModule() {}
448 
449 void CodeGenModule::createObjCRuntime() {
450   // This is just isGNUFamily(), but we want to force implementors of
451   // new ABIs to decide how best to do this.
452   switch (LangOpts.ObjCRuntime.getKind()) {
453   case ObjCRuntime::GNUstep:
454   case ObjCRuntime::GCC:
455   case ObjCRuntime::ObjFW:
456     ObjCRuntime.reset(CreateGNUObjCRuntime(*this));
457     return;
458 
459   case ObjCRuntime::FragileMacOSX:
460   case ObjCRuntime::MacOSX:
461   case ObjCRuntime::iOS:
462   case ObjCRuntime::WatchOS:
463     ObjCRuntime.reset(CreateMacObjCRuntime(*this));
464     return;
465   }
466   llvm_unreachable("bad runtime kind");
467 }
468 
469 void CodeGenModule::createOpenCLRuntime() {
470   OpenCLRuntime.reset(new CGOpenCLRuntime(*this));
471 }
472 
473 void CodeGenModule::createOpenMPRuntime() {
474   // Select a specialized code generation class based on the target, if any.
475   // If it does not exist use the default implementation.
476   switch (getTriple().getArch()) {
477   case llvm::Triple::nvptx:
478   case llvm::Triple::nvptx64:
479   case llvm::Triple::amdgcn:
480     assert(getLangOpts().OpenMPIsTargetDevice &&
481            "OpenMP AMDGPU/NVPTX is only prepared to deal with device code.");
482     OpenMPRuntime.reset(new CGOpenMPRuntimeGPU(*this));
483     break;
484   default:
485     if (LangOpts.OpenMPSimd)
486       OpenMPRuntime.reset(new CGOpenMPSIMDRuntime(*this));
487     else
488       OpenMPRuntime.reset(new CGOpenMPRuntime(*this));
489     break;
490   }
491 }
492 
493 void CodeGenModule::createCUDARuntime() {
494   CUDARuntime.reset(CreateNVCUDARuntime(*this));
495 }
496 
497 void CodeGenModule::createHLSLRuntime() {
498   HLSLRuntime.reset(new CGHLSLRuntime(*this));
499 }
500 
501 void CodeGenModule::addReplacement(StringRef Name, llvm::Constant *C) {
502   Replacements[Name] = C;
503 }
504 
505 void CodeGenModule::applyReplacements() {
506   for (auto &I : Replacements) {
507     StringRef MangledName = I.first;
508     llvm::Constant *Replacement = I.second;
509     llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
510     if (!Entry)
511       continue;
512     auto *OldF = cast<llvm::Function>(Entry);
513     auto *NewF = dyn_cast<llvm::Function>(Replacement);
514     if (!NewF) {
515       if (auto *Alias = dyn_cast<llvm::GlobalAlias>(Replacement)) {
516         NewF = dyn_cast<llvm::Function>(Alias->getAliasee());
517       } else {
518         auto *CE = cast<llvm::ConstantExpr>(Replacement);
519         assert(CE->getOpcode() == llvm::Instruction::BitCast ||
520                CE->getOpcode() == llvm::Instruction::GetElementPtr);
521         NewF = dyn_cast<llvm::Function>(CE->getOperand(0));
522       }
523     }
524 
525     // Replace old with new, but keep the old order.
526     OldF->replaceAllUsesWith(Replacement);
527     if (NewF) {
528       NewF->removeFromParent();
529       OldF->getParent()->getFunctionList().insertAfter(OldF->getIterator(),
530                                                        NewF);
531     }
532     OldF->eraseFromParent();
533   }
534 }
535 
536 void CodeGenModule::addGlobalValReplacement(llvm::GlobalValue *GV, llvm::Constant *C) {
537   GlobalValReplacements.push_back(std::make_pair(GV, C));
538 }
539 
540 void CodeGenModule::applyGlobalValReplacements() {
541   for (auto &I : GlobalValReplacements) {
542     llvm::GlobalValue *GV = I.first;
543     llvm::Constant *C = I.second;
544 
545     GV->replaceAllUsesWith(C);
546     GV->eraseFromParent();
547   }
548 }
549 
550 // This is only used in aliases that we created and we know they have a
551 // linear structure.
552 static const llvm::GlobalValue *getAliasedGlobal(const llvm::GlobalValue *GV) {
553   const llvm::Constant *C;
554   if (auto *GA = dyn_cast<llvm::GlobalAlias>(GV))
555     C = GA->getAliasee();
556   else if (auto *GI = dyn_cast<llvm::GlobalIFunc>(GV))
557     C = GI->getResolver();
558   else
559     return GV;
560 
561   const auto *AliaseeGV = dyn_cast<llvm::GlobalValue>(C->stripPointerCasts());
562   if (!AliaseeGV)
563     return nullptr;
564 
565   const llvm::GlobalValue *FinalGV = AliaseeGV->getAliaseeObject();
566   if (FinalGV == GV)
567     return nullptr;
568 
569   return FinalGV;
570 }
571 
572 static bool checkAliasedGlobal(
573     const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation Location,
574     bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
575     const llvm::MapVector<GlobalDecl, StringRef> &MangledDeclNames,
576     SourceRange AliasRange) {
577   GV = getAliasedGlobal(Alias);
578   if (!GV) {
579     Diags.Report(Location, diag::err_cyclic_alias) << IsIFunc;
580     return false;
581   }
582 
583   if (GV->hasCommonLinkage()) {
584     const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
585     if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
586       Diags.Report(Location, diag::err_alias_to_common);
587       return false;
588     }
589   }
590 
591   if (GV->isDeclaration()) {
592     Diags.Report(Location, diag::err_alias_to_undefined) << IsIFunc << IsIFunc;
593     Diags.Report(Location, diag::note_alias_requires_mangled_name)
594         << IsIFunc << IsIFunc;
595     // Provide a note if the given function is not found and exists as a
596     // mangled name.
597     for (const auto &[Decl, Name] : MangledDeclNames) {
598       if (const auto *ND = dyn_cast<NamedDecl>(Decl.getDecl())) {
599         if (ND->getName() == GV->getName()) {
600           Diags.Report(Location, diag::note_alias_mangled_name_alternative)
601               << Name
602               << FixItHint::CreateReplacement(
603                      AliasRange,
604                      (Twine(IsIFunc ? "ifunc" : "alias") + "(\"" + Name + "\")")
605                          .str());
606         }
607       }
608     }
609     return false;
610   }
611 
612   if (IsIFunc) {
613     // Check resolver function type.
614     const auto *F = dyn_cast<llvm::Function>(GV);
615     if (!F) {
616       Diags.Report(Location, diag::err_alias_to_undefined)
617           << IsIFunc << IsIFunc;
618       return false;
619     }
620 
621     llvm::FunctionType *FTy = F->getFunctionType();
622     if (!FTy->getReturnType()->isPointerTy()) {
623       Diags.Report(Location, diag::err_ifunc_resolver_return);
624       return false;
625     }
626   }
627 
628   return true;
629 }
630 
631 // Emit a warning if toc-data attribute is requested for global variables that
632 // have aliases and remove the toc-data attribute.
633 static void checkAliasForTocData(llvm::GlobalVariable *GVar,
634                                  const CodeGenOptions &CodeGenOpts,
635                                  DiagnosticsEngine &Diags,
636                                  SourceLocation Location) {
637   if (GVar->hasAttribute("toc-data")) {
638     auto GVId = GVar->getName();
639     // Is this a global variable specified by the user as local?
640     if ((llvm::binary_search(CodeGenOpts.TocDataVarsUserSpecified, GVId))) {
641       Diags.Report(Location, diag::warn_toc_unsupported_type)
642           << GVId << "the variable has an alias";
643     }
644     llvm::AttributeSet CurrAttributes = GVar->getAttributes();
645     llvm::AttributeSet NewAttributes =
646         CurrAttributes.removeAttribute(GVar->getContext(), "toc-data");
647     GVar->setAttributes(NewAttributes);
648   }
649 }
650 
651 void CodeGenModule::checkAliases() {
652   // Check if the constructed aliases are well formed. It is really unfortunate
653   // that we have to do this in CodeGen, but we only construct mangled names
654   // and aliases during codegen.
655   bool Error = false;
656   DiagnosticsEngine &Diags = getDiags();
657   for (const GlobalDecl &GD : Aliases) {
658     const auto *D = cast<ValueDecl>(GD.getDecl());
659     SourceLocation Location;
660     SourceRange Range;
661     bool IsIFunc = D->hasAttr<IFuncAttr>();
662     if (const Attr *A = D->getDefiningAttr()) {
663       Location = A->getLocation();
664       Range = A->getRange();
665     } else
666       llvm_unreachable("Not an alias or ifunc?");
667 
668     StringRef MangledName = getMangledName(GD);
669     llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
670     const llvm::GlobalValue *GV = nullptr;
671     if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
672                             MangledDeclNames, Range)) {
673       Error = true;
674       continue;
675     }
676 
677     if (getContext().getTargetInfo().getTriple().isOSAIX())
678       if (const llvm::GlobalVariable *GVar =
679               dyn_cast<const llvm::GlobalVariable>(GV))
680         checkAliasForTocData(const_cast<llvm::GlobalVariable *>(GVar),
681                              getCodeGenOpts(), Diags, Location);
682 
683     llvm::Constant *Aliasee =
684         IsIFunc ? cast<llvm::GlobalIFunc>(Alias)->getResolver()
685                 : cast<llvm::GlobalAlias>(Alias)->getAliasee();
686 
687     llvm::GlobalValue *AliaseeGV;
688     if (auto CE = dyn_cast<llvm::ConstantExpr>(Aliasee))
689       AliaseeGV = cast<llvm::GlobalValue>(CE->getOperand(0));
690     else
691       AliaseeGV = cast<llvm::GlobalValue>(Aliasee);
692 
693     if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
694       StringRef AliasSection = SA->getName();
695       if (AliasSection != AliaseeGV->getSection())
696         Diags.Report(SA->getLocation(), diag::warn_alias_with_section)
697             << AliasSection << IsIFunc << IsIFunc;
698     }
699 
700     // We have to handle alias to weak aliases in here. LLVM itself disallows
701     // this since the object semantics would not match the IL one. For
702     // compatibility with gcc we implement it by just pointing the alias
703     // to its aliasee's aliasee. We also warn, since the user is probably
704     // expecting the link to be weak.
705     if (auto *GA = dyn_cast<llvm::GlobalAlias>(AliaseeGV)) {
706       if (GA->isInterposable()) {
707         Diags.Report(Location, diag::warn_alias_to_weak_alias)
708             << GV->getName() << GA->getName() << IsIFunc;
709         Aliasee = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
710             GA->getAliasee(), Alias->getType());
711 
712         if (IsIFunc)
713           cast<llvm::GlobalIFunc>(Alias)->setResolver(Aliasee);
714         else
715           cast<llvm::GlobalAlias>(Alias)->setAliasee(Aliasee);
716       }
717     }
718   }
719   if (!Error)
720     return;
721 
722   for (const GlobalDecl &GD : Aliases) {
723     StringRef MangledName = getMangledName(GD);
724     llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
725     Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
726     Alias->eraseFromParent();
727   }
728 }
729 
730 void CodeGenModule::clear() {
731   DeferredDeclsToEmit.clear();
732   EmittedDeferredDecls.clear();
733   DeferredAnnotations.clear();
734   if (OpenMPRuntime)
735     OpenMPRuntime->clear();
736 }
737 
738 void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
739                                        StringRef MainFile) {
740   if (!hasDiagnostics())
741     return;
742   if (VisitedInMainFile > 0 && VisitedInMainFile == MissingInMainFile) {
743     if (MainFile.empty())
744       MainFile = "<stdin>";
745     Diags.Report(diag::warn_profile_data_unprofiled) << MainFile;
746   } else {
747     if (Mismatched > 0)
748       Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Mismatched;
749 
750     if (Missing > 0)
751       Diags.Report(diag::warn_profile_data_missing) << Visited << Missing;
752   }
753 }
754 
755 static std::optional<llvm::GlobalValue::VisibilityTypes>
756 getLLVMVisibility(clang::LangOptions::VisibilityFromDLLStorageClassKinds K) {
757   // Map to LLVM visibility.
758   switch (K) {
759   case clang::LangOptions::VisibilityFromDLLStorageClassKinds::Keep:
760     return std::nullopt;
761   case clang::LangOptions::VisibilityFromDLLStorageClassKinds::Default:
762     return llvm::GlobalValue::DefaultVisibility;
763   case clang::LangOptions::VisibilityFromDLLStorageClassKinds::Hidden:
764     return llvm::GlobalValue::HiddenVisibility;
765   case clang::LangOptions::VisibilityFromDLLStorageClassKinds::Protected:
766     return llvm::GlobalValue::ProtectedVisibility;
767   }
768   llvm_unreachable("unknown option value!");
769 }
770 
771 void setLLVMVisibility(llvm::GlobalValue &GV,
772                        std::optional<llvm::GlobalValue::VisibilityTypes> V) {
773   if (!V)
774     return;
775 
776   // Reset DSO locality before setting the visibility. This removes
777   // any effects that visibility options and annotations may have
778   // had on the DSO locality. Setting the visibility will implicitly set
779   // appropriate globals to DSO Local; however, this will be pessimistic
780   // w.r.t. to the normal compiler IRGen.
781   GV.setDSOLocal(false);
782   GV.setVisibility(*V);
783 }
784 
785 static void setVisibilityFromDLLStorageClass(const clang::LangOptions &LO,
786                                              llvm::Module &M) {
787   if (!LO.VisibilityFromDLLStorageClass)
788     return;
789 
790   std::optional<llvm::GlobalValue::VisibilityTypes> DLLExportVisibility =
791       getLLVMVisibility(LO.getDLLExportVisibility());
792 
793   std::optional<llvm::GlobalValue::VisibilityTypes>
794       NoDLLStorageClassVisibility =
795           getLLVMVisibility(LO.getNoDLLStorageClassVisibility());
796 
797   std::optional<llvm::GlobalValue::VisibilityTypes>
798       ExternDeclDLLImportVisibility =
799           getLLVMVisibility(LO.getExternDeclDLLImportVisibility());
800 
801   std::optional<llvm::GlobalValue::VisibilityTypes>
802       ExternDeclNoDLLStorageClassVisibility =
803           getLLVMVisibility(LO.getExternDeclNoDLLStorageClassVisibility());
804 
805   for (llvm::GlobalValue &GV : M.global_values()) {
806     if (GV.hasAppendingLinkage() || GV.hasLocalLinkage())
807       continue;
808 
809     if (GV.isDeclarationForLinker())
810       setLLVMVisibility(GV, GV.getDLLStorageClass() ==
811                                     llvm::GlobalValue::DLLImportStorageClass
812                                 ? ExternDeclDLLImportVisibility
813                                 : ExternDeclNoDLLStorageClassVisibility);
814     else
815       setLLVMVisibility(GV, GV.getDLLStorageClass() ==
816                                     llvm::GlobalValue::DLLExportStorageClass
817                                 ? DLLExportVisibility
818                                 : NoDLLStorageClassVisibility);
819 
820     GV.setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
821   }
822 }
823 
824 static bool isStackProtectorOn(const LangOptions &LangOpts,
825                                const llvm::Triple &Triple,
826                                clang::LangOptions::StackProtectorMode Mode) {
827   if (Triple.isAMDGPU() || Triple.isNVPTX())
828     return false;
829   return LangOpts.getStackProtector() == Mode;
830 }
831 
832 void CodeGenModule::Release() {
833   Module *Primary = getContext().getCurrentNamedModule();
834   if (CXX20ModuleInits && Primary && !Primary->isHeaderLikeModule())
835     EmitModuleInitializers(Primary);
836   EmitDeferred();
837   DeferredDecls.insert(EmittedDeferredDecls.begin(),
838                        EmittedDeferredDecls.end());
839   EmittedDeferredDecls.clear();
840   EmitVTablesOpportunistically();
841   applyGlobalValReplacements();
842   applyReplacements();
843   emitMultiVersionFunctions();
844 
845   if (Context.getLangOpts().IncrementalExtensions &&
846       GlobalTopLevelStmtBlockInFlight.first) {
847     const TopLevelStmtDecl *TLSD = GlobalTopLevelStmtBlockInFlight.second;
848     GlobalTopLevelStmtBlockInFlight.first->FinishFunction(TLSD->getEndLoc());
849     GlobalTopLevelStmtBlockInFlight = {nullptr, nullptr};
850   }
851 
852   // Module implementations are initialized the same way as a regular TU that
853   // imports one or more modules.
854   if (CXX20ModuleInits && Primary && Primary->isInterfaceOrPartition())
855     EmitCXXModuleInitFunc(Primary);
856   else
857     EmitCXXGlobalInitFunc();
858   EmitCXXGlobalCleanUpFunc();
859   registerGlobalDtorsWithAtExit();
860   EmitCXXThreadLocalInitFunc();
861   if (ObjCRuntime)
862     if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
863       AddGlobalCtor(ObjCInitFunction);
864   if (Context.getLangOpts().CUDA && CUDARuntime) {
865     if (llvm::Function *CudaCtorFunction = CUDARuntime->finalizeModule())
866       AddGlobalCtor(CudaCtorFunction);
867   }
868   if (OpenMPRuntime) {
869     OpenMPRuntime->createOffloadEntriesAndInfoMetadata();
870     OpenMPRuntime->clear();
871   }
872   if (PGOReader) {
873     getModule().setProfileSummary(
874         PGOReader->getSummary(/* UseCS */ false).getMD(VMContext),
875         llvm::ProfileSummary::PSK_Instr);
876     if (PGOStats.hasDiagnostics())
877       PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName);
878   }
879   llvm::stable_sort(GlobalCtors, [](const Structor &L, const Structor &R) {
880     return L.LexOrder < R.LexOrder;
881   });
882   EmitCtorList(GlobalCtors, "llvm.global_ctors");
883   EmitCtorList(GlobalDtors, "llvm.global_dtors");
884   EmitGlobalAnnotations();
885   EmitStaticExternCAliases();
886   checkAliases();
887   EmitDeferredUnusedCoverageMappings();
888   CodeGenPGO(*this).setValueProfilingFlag(getModule());
889   CodeGenPGO(*this).setProfileVersion(getModule());
890   if (CoverageMapping)
891     CoverageMapping->emit();
892   if (CodeGenOpts.SanitizeCfiCrossDso) {
893     CodeGenFunction(*this).EmitCfiCheckFail();
894     CodeGenFunction(*this).EmitCfiCheckStub();
895   }
896   if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
897     finalizeKCFITypes();
898   emitAtAvailableLinkGuard();
899   if (Context.getTargetInfo().getTriple().isWasm())
900     EmitMainVoidAlias();
901 
902   if (getTriple().isAMDGPU()) {
903     // Emit amdhsa_code_object_version module flag, which is code object version
904     // times 100.
905     if (getTarget().getTargetOpts().CodeObjectVersion !=
906         llvm::CodeObjectVersionKind::COV_None) {
907       getModule().addModuleFlag(llvm::Module::Error,
908                                 "amdhsa_code_object_version",
909                                 getTarget().getTargetOpts().CodeObjectVersion);
910     }
911 
912     // Currently, "-mprintf-kind" option is only supported for HIP
913     if (LangOpts.HIP) {
914       auto *MDStr = llvm::MDString::get(
915           getLLVMContext(), (getTarget().getTargetOpts().AMDGPUPrintfKindVal ==
916                              TargetOptions::AMDGPUPrintfKind::Hostcall)
917                                 ? "hostcall"
918                                 : "buffered");
919       getModule().addModuleFlag(llvm::Module::Error, "amdgpu_printf_kind",
920                                 MDStr);
921     }
922   }
923 
924   // Emit a global array containing all external kernels or device variables
925   // used by host functions and mark it as used for CUDA/HIP. This is necessary
926   // to get kernels or device variables in archives linked in even if these
927   // kernels or device variables are only used in host functions.
928   if (!Context.CUDAExternalDeviceDeclODRUsedByHost.empty()) {
929     SmallVector<llvm::Constant *, 8> UsedArray;
930     for (auto D : Context.CUDAExternalDeviceDeclODRUsedByHost) {
931       GlobalDecl GD;
932       if (auto *FD = dyn_cast<FunctionDecl>(D))
933         GD = GlobalDecl(FD, KernelReferenceKind::Kernel);
934       else
935         GD = GlobalDecl(D);
936       UsedArray.push_back(llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
937           GetAddrOfGlobal(GD), Int8PtrTy));
938     }
939 
940     llvm::ArrayType *ATy = llvm::ArrayType::get(Int8PtrTy, UsedArray.size());
941 
942     auto *GV = new llvm::GlobalVariable(
943         getModule(), ATy, false, llvm::GlobalValue::InternalLinkage,
944         llvm::ConstantArray::get(ATy, UsedArray), "__clang_gpu_used_external");
945     addCompilerUsedGlobal(GV);
946   }
947   if (LangOpts.HIP && !getLangOpts().OffloadingNewDriver) {
948     // Emit a unique ID so that host and device binaries from the same
949     // compilation unit can be associated.
950     auto *GV = new llvm::GlobalVariable(
951         getModule(), Int8Ty, false, llvm::GlobalValue::ExternalLinkage,
952         llvm::Constant::getNullValue(Int8Ty),
953         "__hip_cuid_" + getContext().getCUIDHash());
954     addCompilerUsedGlobal(GV);
955   }
956   emitLLVMUsed();
957   if (SanStats)
958     SanStats->finish();
959 
960   if (CodeGenOpts.Autolink &&
961       (Context.getLangOpts().Modules || !LinkerOptionsMetadata.empty())) {
962     EmitModuleLinkOptions();
963   }
964 
965   // On ELF we pass the dependent library specifiers directly to the linker
966   // without manipulating them. This is in contrast to other platforms where
967   // they are mapped to a specific linker option by the compiler. This
968   // difference is a result of the greater variety of ELF linkers and the fact
969   // that ELF linkers tend to handle libraries in a more complicated fashion
970   // than on other platforms. This forces us to defer handling the dependent
971   // libs to the linker.
972   //
973   // CUDA/HIP device and host libraries are different. Currently there is no
974   // way to differentiate dependent libraries for host or device. Existing
975   // usage of #pragma comment(lib, *) is intended for host libraries on
976   // Windows. Therefore emit llvm.dependent-libraries only for host.
977   if (!ELFDependentLibraries.empty() && !Context.getLangOpts().CUDAIsDevice) {
978     auto *NMD = getModule().getOrInsertNamedMetadata("llvm.dependent-libraries");
979     for (auto *MD : ELFDependentLibraries)
980       NMD->addOperand(MD);
981   }
982 
983   // Record mregparm value now so it is visible through rest of codegen.
984   if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
985     getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
986                               CodeGenOpts.NumRegisterParameters);
987 
988   if (CodeGenOpts.DwarfVersion) {
989     getModule().addModuleFlag(llvm::Module::Max, "Dwarf Version",
990                               CodeGenOpts.DwarfVersion);
991   }
992 
993   if (CodeGenOpts.Dwarf64)
994     getModule().addModuleFlag(llvm::Module::Max, "DWARF64", 1);
995 
996   if (Context.getLangOpts().SemanticInterposition)
997     // Require various optimization to respect semantic interposition.
998     getModule().setSemanticInterposition(true);
999 
1000   if (CodeGenOpts.EmitCodeView) {
1001     // Indicate that we want CodeView in the metadata.
1002     getModule().addModuleFlag(llvm::Module::Warning, "CodeView", 1);
1003   }
1004   if (CodeGenOpts.CodeViewGHash) {
1005     getModule().addModuleFlag(llvm::Module::Warning, "CodeViewGHash", 1);
1006   }
1007   if (CodeGenOpts.ControlFlowGuard) {
1008     // Function ID tables and checks for Control Flow Guard (cfguard=2).
1009     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 2);
1010   } else if (CodeGenOpts.ControlFlowGuardNoChecks) {
1011     // Function ID tables for Control Flow Guard (cfguard=1).
1012     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 1);
1013   }
1014   if (CodeGenOpts.EHContGuard) {
1015     // Function ID tables for EH Continuation Guard.
1016     getModule().addModuleFlag(llvm::Module::Warning, "ehcontguard", 1);
1017   }
1018   if (Context.getLangOpts().Kernel) {
1019     // Note if we are compiling with /kernel.
1020     getModule().addModuleFlag(llvm::Module::Warning, "ms-kernel", 1);
1021   }
1022   if (CodeGenOpts.OptimizationLevel > 0 && CodeGenOpts.StrictVTablePointers) {
1023     // We don't support LTO with 2 with different StrictVTablePointers
1024     // FIXME: we could support it by stripping all the information introduced
1025     // by StrictVTablePointers.
1026 
1027     getModule().addModuleFlag(llvm::Module::Error, "StrictVTablePointers",1);
1028 
1029     llvm::Metadata *Ops[2] = {
1030               llvm::MDString::get(VMContext, "StrictVTablePointers"),
1031               llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1032                   llvm::Type::getInt32Ty(VMContext), 1))};
1033 
1034     getModule().addModuleFlag(llvm::Module::Require,
1035                               "StrictVTablePointersRequirement",
1036                               llvm::MDNode::get(VMContext, Ops));
1037   }
1038   if (getModuleDebugInfo())
1039     // We support a single version in the linked module. The LLVM
1040     // parser will drop debug info with a different version number
1041     // (and warn about it, too).
1042     getModule().addModuleFlag(llvm::Module::Warning, "Debug Info Version",
1043                               llvm::DEBUG_METADATA_VERSION);
1044 
1045   // We need to record the widths of enums and wchar_t, so that we can generate
1046   // the correct build attributes in the ARM backend. wchar_size is also used by
1047   // TargetLibraryInfo.
1048   uint64_t WCharWidth =
1049       Context.getTypeSizeInChars(Context.getWideCharType()).getQuantity();
1050   getModule().addModuleFlag(llvm::Module::Error, "wchar_size", WCharWidth);
1051 
1052   if (getTriple().isOSzOS()) {
1053     getModule().addModuleFlag(llvm::Module::Warning,
1054                               "zos_product_major_version",
1055                               uint32_t(CLANG_VERSION_MAJOR));
1056     getModule().addModuleFlag(llvm::Module::Warning,
1057                               "zos_product_minor_version",
1058                               uint32_t(CLANG_VERSION_MINOR));
1059     getModule().addModuleFlag(llvm::Module::Warning, "zos_product_patchlevel",
1060                               uint32_t(CLANG_VERSION_PATCHLEVEL));
1061     std::string ProductId = getClangVendor() + "clang";
1062     getModule().addModuleFlag(llvm::Module::Error, "zos_product_id",
1063                               llvm::MDString::get(VMContext, ProductId));
1064 
1065     // Record the language because we need it for the PPA2.
1066     StringRef lang_str = languageToString(
1067         LangStandard::getLangStandardForKind(LangOpts.LangStd).Language);
1068     getModule().addModuleFlag(llvm::Module::Error, "zos_cu_language",
1069                               llvm::MDString::get(VMContext, lang_str));
1070 
1071     time_t TT = PreprocessorOpts.SourceDateEpoch
1072                     ? *PreprocessorOpts.SourceDateEpoch
1073                     : std::time(nullptr);
1074     getModule().addModuleFlag(llvm::Module::Max, "zos_translation_time",
1075                               static_cast<uint64_t>(TT));
1076 
1077     // Multiple modes will be supported here.
1078     getModule().addModuleFlag(llvm::Module::Error, "zos_le_char_mode",
1079                               llvm::MDString::get(VMContext, "ascii"));
1080   }
1081 
1082   llvm::Triple T = Context.getTargetInfo().getTriple();
1083   if (T.isARM() || T.isThumb()) {
1084     // The minimum width of an enum in bytes
1085     uint64_t EnumWidth = Context.getLangOpts().ShortEnums ? 1 : 4;
1086     getModule().addModuleFlag(llvm::Module::Error, "min_enum_size", EnumWidth);
1087   }
1088 
1089   if (T.isRISCV()) {
1090     StringRef ABIStr = Target.getABI();
1091     llvm::LLVMContext &Ctx = TheModule.getContext();
1092     getModule().addModuleFlag(llvm::Module::Error, "target-abi",
1093                               llvm::MDString::get(Ctx, ABIStr));
1094 
1095     // Add the canonical ISA string as metadata so the backend can set the ELF
1096     // attributes correctly. We use AppendUnique so LTO will keep all of the
1097     // unique ISA strings that were linked together.
1098     const std::vector<std::string> &Features =
1099         getTarget().getTargetOpts().Features;
1100     auto ParseResult =
1101         llvm::RISCVISAInfo::parseFeatures(T.isRISCV64() ? 64 : 32, Features);
1102     if (!errorToBool(ParseResult.takeError()))
1103       getModule().addModuleFlag(
1104           llvm::Module::AppendUnique, "riscv-isa",
1105           llvm::MDNode::get(
1106               Ctx, llvm::MDString::get(Ctx, (*ParseResult)->toString())));
1107   }
1108 
1109   if (CodeGenOpts.SanitizeCfiCrossDso) {
1110     // Indicate that we want cross-DSO control flow integrity checks.
1111     getModule().addModuleFlag(llvm::Module::Override, "Cross-DSO CFI", 1);
1112   }
1113 
1114   if (CodeGenOpts.WholeProgramVTables) {
1115     // Indicate whether VFE was enabled for this module, so that the
1116     // vcall_visibility metadata added under whole program vtables is handled
1117     // appropriately in the optimizer.
1118     getModule().addModuleFlag(llvm::Module::Error, "Virtual Function Elim",
1119                               CodeGenOpts.VirtualFunctionElimination);
1120   }
1121 
1122   if (LangOpts.Sanitize.has(SanitizerKind::CFIICall)) {
1123     getModule().addModuleFlag(llvm::Module::Override,
1124                               "CFI Canonical Jump Tables",
1125                               CodeGenOpts.SanitizeCfiCanonicalJumpTables);
1126   }
1127 
1128   if (LangOpts.Sanitize.has(SanitizerKind::KCFI)) {
1129     getModule().addModuleFlag(llvm::Module::Override, "kcfi", 1);
1130     // KCFI assumes patchable-function-prefix is the same for all indirectly
1131     // called functions. Store the expected offset for code generation.
1132     if (CodeGenOpts.PatchableFunctionEntryOffset)
1133       getModule().addModuleFlag(llvm::Module::Override, "kcfi-offset",
1134                                 CodeGenOpts.PatchableFunctionEntryOffset);
1135   }
1136 
1137   if (CodeGenOpts.CFProtectionReturn &&
1138       Target.checkCFProtectionReturnSupported(getDiags())) {
1139     // Indicate that we want to instrument return control flow protection.
1140     getModule().addModuleFlag(llvm::Module::Min, "cf-protection-return",
1141                               1);
1142   }
1143 
1144   if (CodeGenOpts.CFProtectionBranch &&
1145       Target.checkCFProtectionBranchSupported(getDiags())) {
1146     // Indicate that we want to instrument branch control flow protection.
1147     getModule().addModuleFlag(llvm::Module::Min, "cf-protection-branch",
1148                               1);
1149   }
1150 
1151   if (CodeGenOpts.FunctionReturnThunks)
1152     getModule().addModuleFlag(llvm::Module::Override, "function_return_thunk_extern", 1);
1153 
1154   if (CodeGenOpts.IndirectBranchCSPrefix)
1155     getModule().addModuleFlag(llvm::Module::Override, "indirect_branch_cs_prefix", 1);
1156 
1157   // Add module metadata for return address signing (ignoring
1158   // non-leaf/all) and stack tagging. These are actually turned on by function
1159   // attributes, but we use module metadata to emit build attributes. This is
1160   // needed for LTO, where the function attributes are inside bitcode
1161   // serialised into a global variable by the time build attributes are
1162   // emitted, so we can't access them. LTO objects could be compiled with
1163   // different flags therefore module flags are set to "Min" behavior to achieve
1164   // the same end result of the normal build where e.g BTI is off if any object
1165   // doesn't support it.
1166   if (Context.getTargetInfo().hasFeature("ptrauth") &&
1167       LangOpts.getSignReturnAddressScope() !=
1168           LangOptions::SignReturnAddressScopeKind::None)
1169     getModule().addModuleFlag(llvm::Module::Override,
1170                               "sign-return-address-buildattr", 1);
1171   if (LangOpts.Sanitize.has(SanitizerKind::MemtagStack))
1172     getModule().addModuleFlag(llvm::Module::Override,
1173                               "tag-stack-memory-buildattr", 1);
1174 
1175   if (T.isARM() || T.isThumb() || T.isAArch64()) {
1176     if (LangOpts.BranchTargetEnforcement)
1177       getModule().addModuleFlag(llvm::Module::Min, "branch-target-enforcement",
1178                                 1);
1179     if (LangOpts.BranchProtectionPAuthLR)
1180       getModule().addModuleFlag(llvm::Module::Min, "branch-protection-pauth-lr",
1181                                 1);
1182     if (LangOpts.GuardedControlStack)
1183       getModule().addModuleFlag(llvm::Module::Min, "guarded-control-stack", 1);
1184     if (LangOpts.hasSignReturnAddress())
1185       getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 1);
1186     if (LangOpts.isSignReturnAddressScopeAll())
1187       getModule().addModuleFlag(llvm::Module::Min, "sign-return-address-all",
1188                                 1);
1189     if (!LangOpts.isSignReturnAddressWithAKey())
1190       getModule().addModuleFlag(llvm::Module::Min,
1191                                 "sign-return-address-with-bkey", 1);
1192   }
1193 
1194   if (CodeGenOpts.StackClashProtector)
1195     getModule().addModuleFlag(
1196         llvm::Module::Override, "probe-stack",
1197         llvm::MDString::get(TheModule.getContext(), "inline-asm"));
1198 
1199   if (CodeGenOpts.StackProbeSize && CodeGenOpts.StackProbeSize != 4096)
1200     getModule().addModuleFlag(llvm::Module::Min, "stack-probe-size",
1201                               CodeGenOpts.StackProbeSize);
1202 
1203   if (!CodeGenOpts.MemoryProfileOutput.empty()) {
1204     llvm::LLVMContext &Ctx = TheModule.getContext();
1205     getModule().addModuleFlag(
1206         llvm::Module::Error, "MemProfProfileFilename",
1207         llvm::MDString::get(Ctx, CodeGenOpts.MemoryProfileOutput));
1208   }
1209 
1210   if (LangOpts.CUDAIsDevice && getTriple().isNVPTX()) {
1211     // Indicate whether __nvvm_reflect should be configured to flush denormal
1212     // floating point values to 0.  (This corresponds to its "__CUDA_FTZ"
1213     // property.)
1214     getModule().addModuleFlag(llvm::Module::Override, "nvvm-reflect-ftz",
1215                               CodeGenOpts.FP32DenormalMode.Output !=
1216                                   llvm::DenormalMode::IEEE);
1217   }
1218 
1219   if (LangOpts.EHAsynch)
1220     getModule().addModuleFlag(llvm::Module::Warning, "eh-asynch", 1);
1221 
1222   // Indicate whether this Module was compiled with -fopenmp
1223   if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
1224     getModule().addModuleFlag(llvm::Module::Max, "openmp", LangOpts.OpenMP);
1225   if (getLangOpts().OpenMPIsTargetDevice)
1226     getModule().addModuleFlag(llvm::Module::Max, "openmp-device",
1227                               LangOpts.OpenMP);
1228 
1229   // Emit OpenCL specific module metadata: OpenCL/SPIR version.
1230   if (LangOpts.OpenCL || (LangOpts.CUDAIsDevice && getTriple().isSPIRV())) {
1231     EmitOpenCLMetadata();
1232     // Emit SPIR version.
1233     if (getTriple().isSPIR()) {
1234       // SPIR v2.0 s2.12 - The SPIR version used by the module is stored in the
1235       // opencl.spir.version named metadata.
1236       // C++ for OpenCL has a distinct mapping for version compatibility with
1237       // OpenCL.
1238       auto Version = LangOpts.getOpenCLCompatibleVersion();
1239       llvm::Metadata *SPIRVerElts[] = {
1240           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1241               Int32Ty, Version / 100)),
1242           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1243               Int32Ty, (Version / 100 > 1) ? 0 : 2))};
1244       llvm::NamedMDNode *SPIRVerMD =
1245           TheModule.getOrInsertNamedMetadata("opencl.spir.version");
1246       llvm::LLVMContext &Ctx = TheModule.getContext();
1247       SPIRVerMD->addOperand(llvm::MDNode::get(Ctx, SPIRVerElts));
1248     }
1249   }
1250 
1251   // HLSL related end of code gen work items.
1252   if (LangOpts.HLSL)
1253     getHLSLRuntime().finishCodeGen();
1254 
1255   if (uint32_t PLevel = Context.getLangOpts().PICLevel) {
1256     assert(PLevel < 3 && "Invalid PIC Level");
1257     getModule().setPICLevel(static_cast<llvm::PICLevel::Level>(PLevel));
1258     if (Context.getLangOpts().PIE)
1259       getModule().setPIELevel(static_cast<llvm::PIELevel::Level>(PLevel));
1260   }
1261 
1262   if (getCodeGenOpts().CodeModel.size() > 0) {
1263     unsigned CM = llvm::StringSwitch<unsigned>(getCodeGenOpts().CodeModel)
1264                   .Case("tiny", llvm::CodeModel::Tiny)
1265                   .Case("small", llvm::CodeModel::Small)
1266                   .Case("kernel", llvm::CodeModel::Kernel)
1267                   .Case("medium", llvm::CodeModel::Medium)
1268                   .Case("large", llvm::CodeModel::Large)
1269                   .Default(~0u);
1270     if (CM != ~0u) {
1271       llvm::CodeModel::Model codeModel = static_cast<llvm::CodeModel::Model>(CM);
1272       getModule().setCodeModel(codeModel);
1273 
1274       if ((CM == llvm::CodeModel::Medium || CM == llvm::CodeModel::Large) &&
1275           Context.getTargetInfo().getTriple().getArch() ==
1276               llvm::Triple::x86_64) {
1277         getModule().setLargeDataThreshold(getCodeGenOpts().LargeDataThreshold);
1278       }
1279     }
1280   }
1281 
1282   if (CodeGenOpts.NoPLT)
1283     getModule().setRtLibUseGOT();
1284   if (getTriple().isOSBinFormatELF() &&
1285       CodeGenOpts.DirectAccessExternalData !=
1286           getModule().getDirectAccessExternalData()) {
1287     getModule().setDirectAccessExternalData(
1288         CodeGenOpts.DirectAccessExternalData);
1289   }
1290   if (CodeGenOpts.UnwindTables)
1291     getModule().setUwtable(llvm::UWTableKind(CodeGenOpts.UnwindTables));
1292 
1293   switch (CodeGenOpts.getFramePointer()) {
1294   case CodeGenOptions::FramePointerKind::None:
1295     // 0 ("none") is the default.
1296     break;
1297   case CodeGenOptions::FramePointerKind::NonLeaf:
1298     getModule().setFramePointer(llvm::FramePointerKind::NonLeaf);
1299     break;
1300   case CodeGenOptions::FramePointerKind::All:
1301     getModule().setFramePointer(llvm::FramePointerKind::All);
1302     break;
1303   }
1304 
1305   SimplifyPersonality();
1306 
1307   if (getCodeGenOpts().EmitDeclMetadata)
1308     EmitDeclMetadata();
1309 
1310   if (getCodeGenOpts().CoverageNotesFile.size() ||
1311       getCodeGenOpts().CoverageDataFile.size())
1312     EmitCoverageFile();
1313 
1314   if (CGDebugInfo *DI = getModuleDebugInfo())
1315     DI->finalize();
1316 
1317   if (getCodeGenOpts().EmitVersionIdentMetadata)
1318     EmitVersionIdentMetadata();
1319 
1320   if (!getCodeGenOpts().RecordCommandLine.empty())
1321     EmitCommandLineMetadata();
1322 
1323   if (!getCodeGenOpts().StackProtectorGuard.empty())
1324     getModule().setStackProtectorGuard(getCodeGenOpts().StackProtectorGuard);
1325   if (!getCodeGenOpts().StackProtectorGuardReg.empty())
1326     getModule().setStackProtectorGuardReg(
1327         getCodeGenOpts().StackProtectorGuardReg);
1328   if (!getCodeGenOpts().StackProtectorGuardSymbol.empty())
1329     getModule().setStackProtectorGuardSymbol(
1330         getCodeGenOpts().StackProtectorGuardSymbol);
1331   if (getCodeGenOpts().StackProtectorGuardOffset != INT_MAX)
1332     getModule().setStackProtectorGuardOffset(
1333         getCodeGenOpts().StackProtectorGuardOffset);
1334   if (getCodeGenOpts().StackAlignment)
1335     getModule().setOverrideStackAlignment(getCodeGenOpts().StackAlignment);
1336   if (getCodeGenOpts().SkipRaxSetup)
1337     getModule().addModuleFlag(llvm::Module::Override, "SkipRaxSetup", 1);
1338   if (getLangOpts().RegCall4)
1339     getModule().addModuleFlag(llvm::Module::Override, "RegCallv4", 1);
1340 
1341   if (getContext().getTargetInfo().getMaxTLSAlign())
1342     getModule().addModuleFlag(llvm::Module::Error, "MaxTLSAlign",
1343                               getContext().getTargetInfo().getMaxTLSAlign());
1344 
1345   getTargetCodeGenInfo().emitTargetGlobals(*this);
1346 
1347   getTargetCodeGenInfo().emitTargetMetadata(*this, MangledDeclNames);
1348 
1349   EmitBackendOptionsMetadata(getCodeGenOpts());
1350 
1351   // If there is device offloading code embed it in the host now.
1352   EmbedObject(&getModule(), CodeGenOpts, getDiags());
1353 
1354   // Set visibility from DLL storage class
1355   // We do this at the end of LLVM IR generation; after any operation
1356   // that might affect the DLL storage class or the visibility, and
1357   // before anything that might act on these.
1358   setVisibilityFromDLLStorageClass(LangOpts, getModule());
1359 }
1360 
1361 void CodeGenModule::EmitOpenCLMetadata() {
1362   // SPIR v2.0 s2.13 - The OpenCL version used by the module is stored in the
1363   // opencl.ocl.version named metadata node.
1364   // C++ for OpenCL has a distinct mapping for versions compatibile with OpenCL.
1365   auto Version = LangOpts.getOpenCLCompatibleVersion();
1366   llvm::Metadata *OCLVerElts[] = {
1367       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1368           Int32Ty, Version / 100)),
1369       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1370           Int32Ty, (Version % 100) / 10))};
1371   llvm::NamedMDNode *OCLVerMD =
1372       TheModule.getOrInsertNamedMetadata("opencl.ocl.version");
1373   llvm::LLVMContext &Ctx = TheModule.getContext();
1374   OCLVerMD->addOperand(llvm::MDNode::get(Ctx, OCLVerElts));
1375 }
1376 
1377 void CodeGenModule::EmitBackendOptionsMetadata(
1378     const CodeGenOptions &CodeGenOpts) {
1379   if (getTriple().isRISCV()) {
1380     getModule().addModuleFlag(llvm::Module::Min, "SmallDataLimit",
1381                               CodeGenOpts.SmallDataLimit);
1382   }
1383 }
1384 
1385 void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
1386   // Make sure that this type is translated.
1387   Types.UpdateCompletedType(TD);
1388 }
1389 
1390 void CodeGenModule::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
1391   // Make sure that this type is translated.
1392   Types.RefreshTypeCacheForClass(RD);
1393 }
1394 
1395 llvm::MDNode *CodeGenModule::getTBAATypeInfo(QualType QTy) {
1396   if (!TBAA)
1397     return nullptr;
1398   return TBAA->getTypeInfo(QTy);
1399 }
1400 
1401 TBAAAccessInfo CodeGenModule::getTBAAAccessInfo(QualType AccessType) {
1402   if (!TBAA)
1403     return TBAAAccessInfo();
1404   if (getLangOpts().CUDAIsDevice) {
1405     // As CUDA builtin surface/texture types are replaced, skip generating TBAA
1406     // access info.
1407     if (AccessType->isCUDADeviceBuiltinSurfaceType()) {
1408       if (getTargetCodeGenInfo().getCUDADeviceBuiltinSurfaceDeviceType() !=
1409           nullptr)
1410         return TBAAAccessInfo();
1411     } else if (AccessType->isCUDADeviceBuiltinTextureType()) {
1412       if (getTargetCodeGenInfo().getCUDADeviceBuiltinTextureDeviceType() !=
1413           nullptr)
1414         return TBAAAccessInfo();
1415     }
1416   }
1417   return TBAA->getAccessInfo(AccessType);
1418 }
1419 
1420 TBAAAccessInfo
1421 CodeGenModule::getTBAAVTablePtrAccessInfo(llvm::Type *VTablePtrType) {
1422   if (!TBAA)
1423     return TBAAAccessInfo();
1424   return TBAA->getVTablePtrAccessInfo(VTablePtrType);
1425 }
1426 
1427 llvm::MDNode *CodeGenModule::getTBAAStructInfo(QualType QTy) {
1428   if (!TBAA)
1429     return nullptr;
1430   return TBAA->getTBAAStructInfo(QTy);
1431 }
1432 
1433 llvm::MDNode *CodeGenModule::getTBAABaseTypeInfo(QualType QTy) {
1434   if (!TBAA)
1435     return nullptr;
1436   return TBAA->getBaseTypeInfo(QTy);
1437 }
1438 
1439 llvm::MDNode *CodeGenModule::getTBAAAccessTagInfo(TBAAAccessInfo Info) {
1440   if (!TBAA)
1441     return nullptr;
1442   return TBAA->getAccessTagInfo(Info);
1443 }
1444 
1445 TBAAAccessInfo CodeGenModule::mergeTBAAInfoForCast(TBAAAccessInfo SourceInfo,
1446                                                    TBAAAccessInfo TargetInfo) {
1447   if (!TBAA)
1448     return TBAAAccessInfo();
1449   return TBAA->mergeTBAAInfoForCast(SourceInfo, TargetInfo);
1450 }
1451 
1452 TBAAAccessInfo
1453 CodeGenModule::mergeTBAAInfoForConditionalOperator(TBAAAccessInfo InfoA,
1454                                                    TBAAAccessInfo InfoB) {
1455   if (!TBAA)
1456     return TBAAAccessInfo();
1457   return TBAA->mergeTBAAInfoForConditionalOperator(InfoA, InfoB);
1458 }
1459 
1460 TBAAAccessInfo
1461 CodeGenModule::mergeTBAAInfoForMemoryTransfer(TBAAAccessInfo DestInfo,
1462                                               TBAAAccessInfo SrcInfo) {
1463   if (!TBAA)
1464     return TBAAAccessInfo();
1465   return TBAA->mergeTBAAInfoForConditionalOperator(DestInfo, SrcInfo);
1466 }
1467 
1468 void CodeGenModule::DecorateInstructionWithTBAA(llvm::Instruction *Inst,
1469                                                 TBAAAccessInfo TBAAInfo) {
1470   if (llvm::MDNode *Tag = getTBAAAccessTagInfo(TBAAInfo))
1471     Inst->setMetadata(llvm::LLVMContext::MD_tbaa, Tag);
1472 }
1473 
1474 void CodeGenModule::DecorateInstructionWithInvariantGroup(
1475     llvm::Instruction *I, const CXXRecordDecl *RD) {
1476   I->setMetadata(llvm::LLVMContext::MD_invariant_group,
1477                  llvm::MDNode::get(getLLVMContext(), {}));
1478 }
1479 
1480 void CodeGenModule::Error(SourceLocation loc, StringRef message) {
1481   unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
1482   getDiags().Report(Context.getFullLoc(loc), diagID) << message;
1483 }
1484 
1485 /// ErrorUnsupported - Print out an error that codegen doesn't support the
1486 /// specified stmt yet.
1487 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type) {
1488   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
1489                                                "cannot compile this %0 yet");
1490   std::string Msg = Type;
1491   getDiags().Report(Context.getFullLoc(S->getBeginLoc()), DiagID)
1492       << Msg << S->getSourceRange();
1493 }
1494 
1495 /// ErrorUnsupported - Print out an error that codegen doesn't support the
1496 /// specified decl yet.
1497 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type) {
1498   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
1499                                                "cannot compile this %0 yet");
1500   std::string Msg = Type;
1501   getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
1502 }
1503 
1504 llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) {
1505   return llvm::ConstantInt::get(SizeTy, size.getQuantity());
1506 }
1507 
1508 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
1509                                         const NamedDecl *D) const {
1510   // Internal definitions always have default visibility.
1511   if (GV->hasLocalLinkage()) {
1512     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
1513     return;
1514   }
1515   if (!D)
1516     return;
1517 
1518   // Set visibility for definitions, and for declarations if requested globally
1519   // or set explicitly.
1520   LinkageInfo LV = D->getLinkageAndVisibility();
1521 
1522   // OpenMP declare target variables must be visible to the host so they can
1523   // be registered. We require protected visibility unless the variable has
1524   // the DT_nohost modifier and does not need to be registered.
1525   if (Context.getLangOpts().OpenMP &&
1526       Context.getLangOpts().OpenMPIsTargetDevice && isa<VarDecl>(D) &&
1527       D->hasAttr<OMPDeclareTargetDeclAttr>() &&
1528       D->getAttr<OMPDeclareTargetDeclAttr>()->getDevType() !=
1529           OMPDeclareTargetDeclAttr::DT_NoHost &&
1530       LV.getVisibility() == HiddenVisibility) {
1531     GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
1532     return;
1533   }
1534 
1535   if (GV->hasDLLExportStorageClass() || GV->hasDLLImportStorageClass()) {
1536     // Reject incompatible dlllstorage and visibility annotations.
1537     if (!LV.isVisibilityExplicit())
1538       return;
1539     if (GV->hasDLLExportStorageClass()) {
1540       if (LV.getVisibility() == HiddenVisibility)
1541         getDiags().Report(D->getLocation(),
1542                           diag::err_hidden_visibility_dllexport);
1543     } else if (LV.getVisibility() != DefaultVisibility) {
1544       getDiags().Report(D->getLocation(),
1545                         diag::err_non_default_visibility_dllimport);
1546     }
1547     return;
1548   }
1549 
1550   if (LV.isVisibilityExplicit() || getLangOpts().SetVisibilityForExternDecls ||
1551       !GV->isDeclarationForLinker())
1552     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
1553 }
1554 
1555 static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
1556                                  llvm::GlobalValue *GV) {
1557   if (GV->hasLocalLinkage())
1558     return true;
1559 
1560   if (!GV->hasDefaultVisibility() && !GV->hasExternalWeakLinkage())
1561     return true;
1562 
1563   // DLLImport explicitly marks the GV as external.
1564   if (GV->hasDLLImportStorageClass())
1565     return false;
1566 
1567   const llvm::Triple &TT = CGM.getTriple();
1568   const auto &CGOpts = CGM.getCodeGenOpts();
1569   if (TT.isWindowsGNUEnvironment()) {
1570     // In MinGW, variables without DLLImport can still be automatically
1571     // imported from a DLL by the linker; don't mark variables that
1572     // potentially could come from another DLL as DSO local.
1573 
1574     // With EmulatedTLS, TLS variables can be autoimported from other DLLs
1575     // (and this actually happens in the public interface of libstdc++), so
1576     // such variables can't be marked as DSO local. (Native TLS variables
1577     // can't be dllimported at all, though.)
1578     if (GV->isDeclarationForLinker() && isa<llvm::GlobalVariable>(GV) &&
1579         (!GV->isThreadLocal() || CGM.getCodeGenOpts().EmulatedTLS) &&
1580         CGOpts.AutoImport)
1581       return false;
1582   }
1583 
1584   // On COFF, don't mark 'extern_weak' symbols as DSO local. If these symbols
1585   // remain unresolved in the link, they can be resolved to zero, which is
1586   // outside the current DSO.
1587   if (TT.isOSBinFormatCOFF() && GV->hasExternalWeakLinkage())
1588     return false;
1589 
1590   // Every other GV is local on COFF.
1591   // Make an exception for windows OS in the triple: Some firmware builds use
1592   // *-win32-macho triples. This (accidentally?) produced windows relocations
1593   // without GOT tables in older clang versions; Keep this behaviour.
1594   // FIXME: even thread local variables?
1595   if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO()))
1596     return true;
1597 
1598   // Only handle COFF and ELF for now.
1599   if (!TT.isOSBinFormatELF())
1600     return false;
1601 
1602   // If this is not an executable, don't assume anything is local.
1603   llvm::Reloc::Model RM = CGOpts.RelocationModel;
1604   const auto &LOpts = CGM.getLangOpts();
1605   if (RM != llvm::Reloc::Static && !LOpts.PIE) {
1606     // On ELF, if -fno-semantic-interposition is specified and the target
1607     // supports local aliases, there will be neither CC1
1608     // -fsemantic-interposition nor -fhalf-no-semantic-interposition. Set
1609     // dso_local on the function if using a local alias is preferable (can avoid
1610     // PLT indirection).
1611     if (!(isa<llvm::Function>(GV) && GV->canBenefitFromLocalAlias()))
1612       return false;
1613     return !(CGM.getLangOpts().SemanticInterposition ||
1614              CGM.getLangOpts().HalfNoSemanticInterposition);
1615   }
1616 
1617   // A definition cannot be preempted from an executable.
1618   if (!GV->isDeclarationForLinker())
1619     return true;
1620 
1621   // Most PIC code sequences that assume that a symbol is local cannot produce a
1622   // 0 if it turns out the symbol is undefined. While this is ABI and relocation
1623   // depended, it seems worth it to handle it here.
1624   if (RM == llvm::Reloc::PIC_ && GV->hasExternalWeakLinkage())
1625     return false;
1626 
1627   // PowerPC64 prefers TOC indirection to avoid copy relocations.
1628   if (TT.isPPC64())
1629     return false;
1630 
1631   if (CGOpts.DirectAccessExternalData) {
1632     // If -fdirect-access-external-data (default for -fno-pic), set dso_local
1633     // for non-thread-local variables. If the symbol is not defined in the
1634     // executable, a copy relocation will be needed at link time. dso_local is
1635     // excluded for thread-local variables because they generally don't support
1636     // copy relocations.
1637     if (auto *Var = dyn_cast<llvm::GlobalVariable>(GV))
1638       if (!Var->isThreadLocal())
1639         return true;
1640 
1641     // -fno-pic sets dso_local on a function declaration to allow direct
1642     // accesses when taking its address (similar to a data symbol). If the
1643     // function is not defined in the executable, a canonical PLT entry will be
1644     // needed at link time. -fno-direct-access-external-data can avoid the
1645     // canonical PLT entry. We don't generalize this condition to -fpie/-fpic as
1646     // it could just cause trouble without providing perceptible benefits.
1647     if (isa<llvm::Function>(GV) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
1648       return true;
1649   }
1650 
1651   // If we can use copy relocations we can assume it is local.
1652 
1653   // Otherwise don't assume it is local.
1654   return false;
1655 }
1656 
1657 void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV) const {
1658   GV->setDSOLocal(shouldAssumeDSOLocal(*this, GV));
1659 }
1660 
1661 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
1662                                           GlobalDecl GD) const {
1663   const auto *D = dyn_cast<NamedDecl>(GD.getDecl());
1664   // C++ destructors have a few C++ ABI specific special cases.
1665   if (const auto *Dtor = dyn_cast_or_null<CXXDestructorDecl>(D)) {
1666     getCXXABI().setCXXDestructorDLLStorage(GV, Dtor, GD.getDtorType());
1667     return;
1668   }
1669   setDLLImportDLLExport(GV, D);
1670 }
1671 
1672 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
1673                                           const NamedDecl *D) const {
1674   if (D && D->isExternallyVisible()) {
1675     if (D->hasAttr<DLLImportAttr>())
1676       GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
1677     else if ((D->hasAttr<DLLExportAttr>() ||
1678               shouldMapVisibilityToDLLExport(D)) &&
1679              !GV->isDeclarationForLinker())
1680       GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
1681   }
1682 }
1683 
1684 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
1685                                     GlobalDecl GD) const {
1686   setDLLImportDLLExport(GV, GD);
1687   setGVPropertiesAux(GV, dyn_cast<NamedDecl>(GD.getDecl()));
1688 }
1689 
1690 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
1691                                     const NamedDecl *D) const {
1692   setDLLImportDLLExport(GV, D);
1693   setGVPropertiesAux(GV, D);
1694 }
1695 
1696 void CodeGenModule::setGVPropertiesAux(llvm::GlobalValue *GV,
1697                                        const NamedDecl *D) const {
1698   setGlobalVisibility(GV, D);
1699   setDSOLocal(GV);
1700   GV->setPartition(CodeGenOpts.SymbolPartition);
1701 }
1702 
1703 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) {
1704   return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S)
1705       .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel)
1706       .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel)
1707       .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel)
1708       .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel);
1709 }
1710 
1711 llvm::GlobalVariable::ThreadLocalMode
1712 CodeGenModule::GetDefaultLLVMTLSModel() const {
1713   switch (CodeGenOpts.getDefaultTLSModel()) {
1714   case CodeGenOptions::GeneralDynamicTLSModel:
1715     return llvm::GlobalVariable::GeneralDynamicTLSModel;
1716   case CodeGenOptions::LocalDynamicTLSModel:
1717     return llvm::GlobalVariable::LocalDynamicTLSModel;
1718   case CodeGenOptions::InitialExecTLSModel:
1719     return llvm::GlobalVariable::InitialExecTLSModel;
1720   case CodeGenOptions::LocalExecTLSModel:
1721     return llvm::GlobalVariable::LocalExecTLSModel;
1722   }
1723   llvm_unreachable("Invalid TLS model!");
1724 }
1725 
1726 void CodeGenModule::setTLSMode(llvm::GlobalValue *GV, const VarDecl &D) const {
1727   assert(D.getTLSKind() && "setting TLS mode on non-TLS var!");
1728 
1729   llvm::GlobalValue::ThreadLocalMode TLM;
1730   TLM = GetDefaultLLVMTLSModel();
1731 
1732   // Override the TLS model if it is explicitly specified.
1733   if (const TLSModelAttr *Attr = D.getAttr<TLSModelAttr>()) {
1734     TLM = GetLLVMTLSModel(Attr->getModel());
1735   }
1736 
1737   GV->setThreadLocalMode(TLM);
1738 }
1739 
1740 static std::string getCPUSpecificMangling(const CodeGenModule &CGM,
1741                                           StringRef Name) {
1742   const TargetInfo &Target = CGM.getTarget();
1743   return (Twine('.') + Twine(Target.CPUSpecificManglingCharacter(Name))).str();
1744 }
1745 
1746 static void AppendCPUSpecificCPUDispatchMangling(const CodeGenModule &CGM,
1747                                                  const CPUSpecificAttr *Attr,
1748                                                  unsigned CPUIndex,
1749                                                  raw_ostream &Out) {
1750   // cpu_specific gets the current name, dispatch gets the resolver if IFunc is
1751   // supported.
1752   if (Attr)
1753     Out << getCPUSpecificMangling(CGM, Attr->getCPUName(CPUIndex)->getName());
1754   else if (CGM.getTarget().supportsIFunc())
1755     Out << ".resolver";
1756 }
1757 
1758 // Returns true if GD is a function decl with internal linkage and
1759 // needs a unique suffix after the mangled name.
1760 static bool isUniqueInternalLinkageDecl(GlobalDecl GD,
1761                                         CodeGenModule &CGM) {
1762   const Decl *D = GD.getDecl();
1763   return !CGM.getModuleNameHash().empty() && isa<FunctionDecl>(D) &&
1764          (CGM.getFunctionLinkage(GD) == llvm::GlobalValue::InternalLinkage);
1765 }
1766 
1767 static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
1768                                       const NamedDecl *ND,
1769                                       bool OmitMultiVersionMangling = false) {
1770   SmallString<256> Buffer;
1771   llvm::raw_svector_ostream Out(Buffer);
1772   MangleContext &MC = CGM.getCXXABI().getMangleContext();
1773   if (!CGM.getModuleNameHash().empty())
1774     MC.needsUniqueInternalLinkageNames();
1775   bool ShouldMangle = MC.shouldMangleDeclName(ND);
1776   if (ShouldMangle)
1777     MC.mangleName(GD.getWithDecl(ND), Out);
1778   else {
1779     IdentifierInfo *II = ND->getIdentifier();
1780     assert(II && "Attempt to mangle unnamed decl.");
1781     const auto *FD = dyn_cast<FunctionDecl>(ND);
1782 
1783     if (FD &&
1784         FD->getType()->castAs<FunctionType>()->getCallConv() == CC_X86RegCall) {
1785       if (CGM.getLangOpts().RegCall4)
1786         Out << "__regcall4__" << II->getName();
1787       else
1788         Out << "__regcall3__" << II->getName();
1789     } else if (FD && FD->hasAttr<CUDAGlobalAttr>() &&
1790                GD.getKernelReferenceKind() == KernelReferenceKind::Stub) {
1791       Out << "__device_stub__" << II->getName();
1792     } else {
1793       Out << II->getName();
1794     }
1795   }
1796 
1797   // Check if the module name hash should be appended for internal linkage
1798   // symbols.   This should come before multi-version target suffixes are
1799   // appended. This is to keep the name and module hash suffix of the
1800   // internal linkage function together.  The unique suffix should only be
1801   // added when name mangling is done to make sure that the final name can
1802   // be properly demangled.  For example, for C functions without prototypes,
1803   // name mangling is not done and the unique suffix should not be appeneded
1804   // then.
1805   if (ShouldMangle && isUniqueInternalLinkageDecl(GD, CGM)) {
1806     assert(CGM.getCodeGenOpts().UniqueInternalLinkageNames &&
1807            "Hash computed when not explicitly requested");
1808     Out << CGM.getModuleNameHash();
1809   }
1810 
1811   if (const auto *FD = dyn_cast<FunctionDecl>(ND))
1812     if (FD->isMultiVersion() && !OmitMultiVersionMangling) {
1813       switch (FD->getMultiVersionKind()) {
1814       case MultiVersionKind::CPUDispatch:
1815       case MultiVersionKind::CPUSpecific:
1816         AppendCPUSpecificCPUDispatchMangling(CGM,
1817                                              FD->getAttr<CPUSpecificAttr>(),
1818                                              GD.getMultiVersionIndex(), Out);
1819         break;
1820       case MultiVersionKind::Target: {
1821         auto *Attr = FD->getAttr<TargetAttr>();
1822         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
1823         Info.appendAttributeMangling(Attr, Out);
1824         break;
1825       }
1826       case MultiVersionKind::TargetVersion: {
1827         auto *Attr = FD->getAttr<TargetVersionAttr>();
1828         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
1829         Info.appendAttributeMangling(Attr, Out);
1830         break;
1831       }
1832       case MultiVersionKind::TargetClones: {
1833         auto *Attr = FD->getAttr<TargetClonesAttr>();
1834         unsigned Index = GD.getMultiVersionIndex();
1835         const ABIInfo &Info = CGM.getTargetCodeGenInfo().getABIInfo();
1836         Info.appendAttributeMangling(Attr, Index, Out);
1837         break;
1838       }
1839       case MultiVersionKind::None:
1840         llvm_unreachable("None multiversion type isn't valid here");
1841       }
1842     }
1843 
1844   // Make unique name for device side static file-scope variable for HIP.
1845   if (CGM.getContext().shouldExternalize(ND) &&
1846       CGM.getLangOpts().GPURelocatableDeviceCode &&
1847       CGM.getLangOpts().CUDAIsDevice)
1848     CGM.printPostfixForExternalizedDecl(Out, ND);
1849 
1850   return std::string(Out.str());
1851 }
1852 
1853 void CodeGenModule::UpdateMultiVersionNames(GlobalDecl GD,
1854                                             const FunctionDecl *FD,
1855                                             StringRef &CurName) {
1856   if (!FD->isMultiVersion())
1857     return;
1858 
1859   // Get the name of what this would be without the 'target' attribute.  This
1860   // allows us to lookup the version that was emitted when this wasn't a
1861   // multiversion function.
1862   std::string NonTargetName =
1863       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
1864   GlobalDecl OtherGD;
1865   if (lookupRepresentativeDecl(NonTargetName, OtherGD)) {
1866     assert(OtherGD.getCanonicalDecl()
1867                .getDecl()
1868                ->getAsFunction()
1869                ->isMultiVersion() &&
1870            "Other GD should now be a multiversioned function");
1871     // OtherFD is the version of this function that was mangled BEFORE
1872     // becoming a MultiVersion function.  It potentially needs to be updated.
1873     const FunctionDecl *OtherFD = OtherGD.getCanonicalDecl()
1874                                       .getDecl()
1875                                       ->getAsFunction()
1876                                       ->getMostRecentDecl();
1877     std::string OtherName = getMangledNameImpl(*this, OtherGD, OtherFD);
1878     // This is so that if the initial version was already the 'default'
1879     // version, we don't try to update it.
1880     if (OtherName != NonTargetName) {
1881       // Remove instead of erase, since others may have stored the StringRef
1882       // to this.
1883       const auto ExistingRecord = Manglings.find(NonTargetName);
1884       if (ExistingRecord != std::end(Manglings))
1885         Manglings.remove(&(*ExistingRecord));
1886       auto Result = Manglings.insert(std::make_pair(OtherName, OtherGD));
1887       StringRef OtherNameRef = MangledDeclNames[OtherGD.getCanonicalDecl()] =
1888           Result.first->first();
1889       // If this is the current decl is being created, make sure we update the name.
1890       if (GD.getCanonicalDecl() == OtherGD.getCanonicalDecl())
1891         CurName = OtherNameRef;
1892       if (llvm::GlobalValue *Entry = GetGlobalValue(NonTargetName))
1893         Entry->setName(OtherName);
1894     }
1895   }
1896 }
1897 
1898 StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
1899   GlobalDecl CanonicalGD = GD.getCanonicalDecl();
1900 
1901   // Some ABIs don't have constructor variants.  Make sure that base and
1902   // complete constructors get mangled the same.
1903   if (const auto *CD = dyn_cast<CXXConstructorDecl>(CanonicalGD.getDecl())) {
1904     if (!getTarget().getCXXABI().hasConstructorVariants()) {
1905       CXXCtorType OrigCtorType = GD.getCtorType();
1906       assert(OrigCtorType == Ctor_Base || OrigCtorType == Ctor_Complete);
1907       if (OrigCtorType == Ctor_Base)
1908         CanonicalGD = GlobalDecl(CD, Ctor_Complete);
1909     }
1910   }
1911 
1912   // In CUDA/HIP device compilation with -fgpu-rdc, the mangled name of a
1913   // static device variable depends on whether the variable is referenced by
1914   // a host or device host function. Therefore the mangled name cannot be
1915   // cached.
1916   if (!LangOpts.CUDAIsDevice || !getContext().mayExternalize(GD.getDecl())) {
1917     auto FoundName = MangledDeclNames.find(CanonicalGD);
1918     if (FoundName != MangledDeclNames.end())
1919       return FoundName->second;
1920   }
1921 
1922   // Keep the first result in the case of a mangling collision.
1923   const auto *ND = cast<NamedDecl>(GD.getDecl());
1924   std::string MangledName = getMangledNameImpl(*this, GD, ND);
1925 
1926   // Ensure either we have different ABIs between host and device compilations,
1927   // says host compilation following MSVC ABI but device compilation follows
1928   // Itanium C++ ABI or, if they follow the same ABI, kernel names after
1929   // mangling should be the same after name stubbing. The later checking is
1930   // very important as the device kernel name being mangled in host-compilation
1931   // is used to resolve the device binaries to be executed. Inconsistent naming
1932   // result in undefined behavior. Even though we cannot check that naming
1933   // directly between host- and device-compilations, the host- and
1934   // device-mangling in host compilation could help catching certain ones.
1935   assert(!isa<FunctionDecl>(ND) || !ND->hasAttr<CUDAGlobalAttr>() ||
1936          getContext().shouldExternalize(ND) || getLangOpts().CUDAIsDevice ||
1937          (getContext().getAuxTargetInfo() &&
1938           (getContext().getAuxTargetInfo()->getCXXABI() !=
1939            getContext().getTargetInfo().getCXXABI())) ||
1940          getCUDARuntime().getDeviceSideName(ND) ==
1941              getMangledNameImpl(
1942                  *this,
1943                  GD.getWithKernelReferenceKind(KernelReferenceKind::Kernel),
1944                  ND));
1945 
1946   auto Result = Manglings.insert(std::make_pair(MangledName, GD));
1947   return MangledDeclNames[CanonicalGD] = Result.first->first();
1948 }
1949 
1950 StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
1951                                              const BlockDecl *BD) {
1952   MangleContext &MangleCtx = getCXXABI().getMangleContext();
1953   const Decl *D = GD.getDecl();
1954 
1955   SmallString<256> Buffer;
1956   llvm::raw_svector_ostream Out(Buffer);
1957   if (!D)
1958     MangleCtx.mangleGlobalBlock(BD,
1959       dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl()), Out);
1960   else if (const auto *CD = dyn_cast<CXXConstructorDecl>(D))
1961     MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Out);
1962   else if (const auto *DD = dyn_cast<CXXDestructorDecl>(D))
1963     MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Out);
1964   else
1965     MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out);
1966 
1967   auto Result = Manglings.insert(std::make_pair(Out.str(), BD));
1968   return Result.first->first();
1969 }
1970 
1971 const GlobalDecl CodeGenModule::getMangledNameDecl(StringRef Name) {
1972   auto it = MangledDeclNames.begin();
1973   while (it != MangledDeclNames.end()) {
1974     if (it->second == Name)
1975       return it->first;
1976     it++;
1977   }
1978   return GlobalDecl();
1979 }
1980 
1981 llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) {
1982   return getModule().getNamedValue(Name);
1983 }
1984 
1985 /// AddGlobalCtor - Add a function to the list that will be called before
1986 /// main() runs.
1987 void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority,
1988                                   unsigned LexOrder,
1989                                   llvm::Constant *AssociatedData) {
1990   // FIXME: Type coercion of void()* types.
1991   GlobalCtors.push_back(Structor(Priority, LexOrder, Ctor, AssociatedData));
1992 }
1993 
1994 /// AddGlobalDtor - Add a function to the list that will be called
1995 /// when the module is unloaded.
1996 void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority,
1997                                   bool IsDtorAttrFunc) {
1998   if (CodeGenOpts.RegisterGlobalDtorsWithAtExit &&
1999       (!getContext().getTargetInfo().getTriple().isOSAIX() || IsDtorAttrFunc)) {
2000     DtorsUsingAtExit[Priority].push_back(Dtor);
2001     return;
2002   }
2003 
2004   // FIXME: Type coercion of void()* types.
2005   GlobalDtors.push_back(Structor(Priority, ~0U, Dtor, nullptr));
2006 }
2007 
2008 void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
2009   if (Fns.empty()) return;
2010 
2011   // Ctor function type is void()*.
2012   llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false);
2013   llvm::Type *CtorPFTy = llvm::PointerType::get(CtorFTy,
2014       TheModule.getDataLayout().getProgramAddressSpace());
2015 
2016   // Get the type of a ctor entry, { i32, void ()*, i8* }.
2017   llvm::StructType *CtorStructTy = llvm::StructType::get(
2018       Int32Ty, CtorPFTy, VoidPtrTy);
2019 
2020   // Construct the constructor and destructor arrays.
2021   ConstantInitBuilder builder(*this);
2022   auto ctors = builder.beginArray(CtorStructTy);
2023   for (const auto &I : Fns) {
2024     auto ctor = ctors.beginStruct(CtorStructTy);
2025     ctor.addInt(Int32Ty, I.Priority);
2026     ctor.add(I.Initializer);
2027     if (I.AssociatedData)
2028       ctor.add(I.AssociatedData);
2029     else
2030       ctor.addNullPointer(VoidPtrTy);
2031     ctor.finishAndAddTo(ctors);
2032   }
2033 
2034   auto list =
2035     ctors.finishAndCreateGlobal(GlobalName, getPointerAlign(),
2036                                 /*constant*/ false,
2037                                 llvm::GlobalValue::AppendingLinkage);
2038 
2039   // The LTO linker doesn't seem to like it when we set an alignment
2040   // on appending variables.  Take it off as a workaround.
2041   list->setAlignment(std::nullopt);
2042 
2043   Fns.clear();
2044 }
2045 
2046 llvm::GlobalValue::LinkageTypes
2047 CodeGenModule::getFunctionLinkage(GlobalDecl GD) {
2048   const auto *D = cast<FunctionDecl>(GD.getDecl());
2049 
2050   GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);
2051 
2052   if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(D))
2053     return getCXXABI().getCXXDestructorLinkage(Linkage, Dtor, GD.getDtorType());
2054 
2055   return getLLVMLinkageForDeclarator(D, Linkage);
2056 }
2057 
2058 llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
2059   llvm::MDString *MDS = dyn_cast<llvm::MDString>(MD);
2060   if (!MDS) return nullptr;
2061 
2062   return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
2063 }
2064 
2065 llvm::ConstantInt *CodeGenModule::CreateKCFITypeId(QualType T) {
2066   if (auto *FnType = T->getAs<FunctionProtoType>())
2067     T = getContext().getFunctionType(
2068         FnType->getReturnType(), FnType->getParamTypes(),
2069         FnType->getExtProtoInfo().withExceptionSpec(EST_None));
2070 
2071   std::string OutName;
2072   llvm::raw_string_ostream Out(OutName);
2073   getCXXABI().getMangleContext().mangleCanonicalTypeName(
2074       T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
2075 
2076   if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
2077     Out << ".normalized";
2078 
2079   return llvm::ConstantInt::get(Int32Ty,
2080                                 static_cast<uint32_t>(llvm::xxHash64(OutName)));
2081 }
2082 
2083 void CodeGenModule::SetLLVMFunctionAttributes(GlobalDecl GD,
2084                                               const CGFunctionInfo &Info,
2085                                               llvm::Function *F, bool IsThunk) {
2086   unsigned CallingConv;
2087   llvm::AttributeList PAL;
2088   ConstructAttributeList(F->getName(), Info, GD, PAL, CallingConv,
2089                          /*AttrOnCallSite=*/false, IsThunk);
2090   if (CallingConv == llvm::CallingConv::X86_VectorCall &&
2091       getTarget().getTriple().isWindowsArm64EC()) {
2092     SourceLocation Loc;
2093     if (const Decl *D = GD.getDecl())
2094       Loc = D->getLocation();
2095 
2096     Error(Loc, "__vectorcall calling convention is not currently supported");
2097   }
2098   F->setAttributes(PAL);
2099   F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
2100 }
2101 
2102 static void removeImageAccessQualifier(std::string& TyName) {
2103   std::string ReadOnlyQual("__read_only");
2104   std::string::size_type ReadOnlyPos = TyName.find(ReadOnlyQual);
2105   if (ReadOnlyPos != std::string::npos)
2106     // "+ 1" for the space after access qualifier.
2107     TyName.erase(ReadOnlyPos, ReadOnlyQual.size() + 1);
2108   else {
2109     std::string WriteOnlyQual("__write_only");
2110     std::string::size_type WriteOnlyPos = TyName.find(WriteOnlyQual);
2111     if (WriteOnlyPos != std::string::npos)
2112       TyName.erase(WriteOnlyPos, WriteOnlyQual.size() + 1);
2113     else {
2114       std::string ReadWriteQual("__read_write");
2115       std::string::size_type ReadWritePos = TyName.find(ReadWriteQual);
2116       if (ReadWritePos != std::string::npos)
2117         TyName.erase(ReadWritePos, ReadWriteQual.size() + 1);
2118     }
2119   }
2120 }
2121 
2122 // Returns the address space id that should be produced to the
2123 // kernel_arg_addr_space metadata. This is always fixed to the ids
2124 // as specified in the SPIR 2.0 specification in order to differentiate
2125 // for example in clGetKernelArgInfo() implementation between the address
2126 // spaces with targets without unique mapping to the OpenCL address spaces
2127 // (basically all single AS CPUs).
2128 static unsigned ArgInfoAddressSpace(LangAS AS) {
2129   switch (AS) {
2130   case LangAS::opencl_global:
2131     return 1;
2132   case LangAS::opencl_constant:
2133     return 2;
2134   case LangAS::opencl_local:
2135     return 3;
2136   case LangAS::opencl_generic:
2137     return 4; // Not in SPIR 2.0 specs.
2138   case LangAS::opencl_global_device:
2139     return 5;
2140   case LangAS::opencl_global_host:
2141     return 6;
2142   default:
2143     return 0; // Assume private.
2144   }
2145 }
2146 
2147 void CodeGenModule::GenKernelArgMetadata(llvm::Function *Fn,
2148                                          const FunctionDecl *FD,
2149                                          CodeGenFunction *CGF) {
2150   assert(((FD && CGF) || (!FD && !CGF)) &&
2151          "Incorrect use - FD and CGF should either be both null or not!");
2152   // Create MDNodes that represent the kernel arg metadata.
2153   // Each MDNode is a list in the form of "key", N number of values which is
2154   // the same number of values as their are kernel arguments.
2155 
2156   const PrintingPolicy &Policy = Context.getPrintingPolicy();
2157 
2158   // MDNode for the kernel argument address space qualifiers.
2159   SmallVector<llvm::Metadata *, 8> addressQuals;
2160 
2161   // MDNode for the kernel argument access qualifiers (images only).
2162   SmallVector<llvm::Metadata *, 8> accessQuals;
2163 
2164   // MDNode for the kernel argument type names.
2165   SmallVector<llvm::Metadata *, 8> argTypeNames;
2166 
2167   // MDNode for the kernel argument base type names.
2168   SmallVector<llvm::Metadata *, 8> argBaseTypeNames;
2169 
2170   // MDNode for the kernel argument type qualifiers.
2171   SmallVector<llvm::Metadata *, 8> argTypeQuals;
2172 
2173   // MDNode for the kernel argument names.
2174   SmallVector<llvm::Metadata *, 8> argNames;
2175 
2176   if (FD && CGF)
2177     for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
2178       const ParmVarDecl *parm = FD->getParamDecl(i);
2179       // Get argument name.
2180       argNames.push_back(llvm::MDString::get(VMContext, parm->getName()));
2181 
2182       if (!getLangOpts().OpenCL)
2183         continue;
2184       QualType ty = parm->getType();
2185       std::string typeQuals;
2186 
2187       // Get image and pipe access qualifier:
2188       if (ty->isImageType() || ty->isPipeType()) {
2189         const Decl *PDecl = parm;
2190         if (const auto *TD = ty->getAs<TypedefType>())
2191           PDecl = TD->getDecl();
2192         const OpenCLAccessAttr *A = PDecl->getAttr<OpenCLAccessAttr>();
2193         if (A && A->isWriteOnly())
2194           accessQuals.push_back(llvm::MDString::get(VMContext, "write_only"));
2195         else if (A && A->isReadWrite())
2196           accessQuals.push_back(llvm::MDString::get(VMContext, "read_write"));
2197         else
2198           accessQuals.push_back(llvm::MDString::get(VMContext, "read_only"));
2199       } else
2200         accessQuals.push_back(llvm::MDString::get(VMContext, "none"));
2201 
2202       auto getTypeSpelling = [&](QualType Ty) {
2203         auto typeName = Ty.getUnqualifiedType().getAsString(Policy);
2204 
2205         if (Ty.isCanonical()) {
2206           StringRef typeNameRef = typeName;
2207           // Turn "unsigned type" to "utype"
2208           if (typeNameRef.consume_front("unsigned "))
2209             return std::string("u") + typeNameRef.str();
2210           if (typeNameRef.consume_front("signed "))
2211             return typeNameRef.str();
2212         }
2213 
2214         return typeName;
2215       };
2216 
2217       if (ty->isPointerType()) {
2218         QualType pointeeTy = ty->getPointeeType();
2219 
2220         // Get address qualifier.
2221         addressQuals.push_back(
2222             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(
2223                 ArgInfoAddressSpace(pointeeTy.getAddressSpace()))));
2224 
2225         // Get argument type name.
2226         std::string typeName = getTypeSpelling(pointeeTy) + "*";
2227         std::string baseTypeName =
2228             getTypeSpelling(pointeeTy.getCanonicalType()) + "*";
2229         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
2230         argBaseTypeNames.push_back(
2231             llvm::MDString::get(VMContext, baseTypeName));
2232 
2233         // Get argument type qualifiers:
2234         if (ty.isRestrictQualified())
2235           typeQuals = "restrict";
2236         if (pointeeTy.isConstQualified() ||
2237             (pointeeTy.getAddressSpace() == LangAS::opencl_constant))
2238           typeQuals += typeQuals.empty() ? "const" : " const";
2239         if (pointeeTy.isVolatileQualified())
2240           typeQuals += typeQuals.empty() ? "volatile" : " volatile";
2241       } else {
2242         uint32_t AddrSpc = 0;
2243         bool isPipe = ty->isPipeType();
2244         if (ty->isImageType() || isPipe)
2245           AddrSpc = ArgInfoAddressSpace(LangAS::opencl_global);
2246 
2247         addressQuals.push_back(
2248             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(AddrSpc)));
2249 
2250         // Get argument type name.
2251         ty = isPipe ? ty->castAs<PipeType>()->getElementType() : ty;
2252         std::string typeName = getTypeSpelling(ty);
2253         std::string baseTypeName = getTypeSpelling(ty.getCanonicalType());
2254 
2255         // Remove access qualifiers on images
2256         // (as they are inseparable from type in clang implementation,
2257         // but OpenCL spec provides a special query to get access qualifier
2258         // via clGetKernelArgInfo with CL_KERNEL_ARG_ACCESS_QUALIFIER):
2259         if (ty->isImageType()) {
2260           removeImageAccessQualifier(typeName);
2261           removeImageAccessQualifier(baseTypeName);
2262         }
2263 
2264         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
2265         argBaseTypeNames.push_back(
2266             llvm::MDString::get(VMContext, baseTypeName));
2267 
2268         if (isPipe)
2269           typeQuals = "pipe";
2270       }
2271       argTypeQuals.push_back(llvm::MDString::get(VMContext, typeQuals));
2272     }
2273 
2274   if (getLangOpts().OpenCL) {
2275     Fn->setMetadata("kernel_arg_addr_space",
2276                     llvm::MDNode::get(VMContext, addressQuals));
2277     Fn->setMetadata("kernel_arg_access_qual",
2278                     llvm::MDNode::get(VMContext, accessQuals));
2279     Fn->setMetadata("kernel_arg_type",
2280                     llvm::MDNode::get(VMContext, argTypeNames));
2281     Fn->setMetadata("kernel_arg_base_type",
2282                     llvm::MDNode::get(VMContext, argBaseTypeNames));
2283     Fn->setMetadata("kernel_arg_type_qual",
2284                     llvm::MDNode::get(VMContext, argTypeQuals));
2285   }
2286   if (getCodeGenOpts().EmitOpenCLArgMetadata ||
2287       getCodeGenOpts().HIPSaveKernelArgName)
2288     Fn->setMetadata("kernel_arg_name",
2289                     llvm::MDNode::get(VMContext, argNames));
2290 }
2291 
2292 /// Determines whether the language options require us to model
2293 /// unwind exceptions.  We treat -fexceptions as mandating this
2294 /// except under the fragile ObjC ABI with only ObjC exceptions
2295 /// enabled.  This means, for example, that C with -fexceptions
2296 /// enables this.
2297 static bool hasUnwindExceptions(const LangOptions &LangOpts) {
2298   // If exceptions are completely disabled, obviously this is false.
2299   if (!LangOpts.Exceptions) return false;
2300 
2301   // If C++ exceptions are enabled, this is true.
2302   if (LangOpts.CXXExceptions) return true;
2303 
2304   // If ObjC exceptions are enabled, this depends on the ABI.
2305   if (LangOpts.ObjCExceptions) {
2306     return LangOpts.ObjCRuntime.hasUnwindExceptions();
2307   }
2308 
2309   return true;
2310 }
2311 
2312 static bool requiresMemberFunctionPointerTypeMetadata(CodeGenModule &CGM,
2313                                                       const CXXMethodDecl *MD) {
2314   // Check that the type metadata can ever actually be used by a call.
2315   if (!CGM.getCodeGenOpts().LTOUnit ||
2316       !CGM.HasHiddenLTOVisibility(MD->getParent()))
2317     return false;
2318 
2319   // Only functions whose address can be taken with a member function pointer
2320   // need this sort of type metadata.
2321   return MD->isImplicitObjectMemberFunction() && !MD->isVirtual() &&
2322          !isa<CXXConstructorDecl, CXXDestructorDecl>(MD);
2323 }
2324 
2325 SmallVector<const CXXRecordDecl *, 0>
2326 CodeGenModule::getMostBaseClasses(const CXXRecordDecl *RD) {
2327   llvm::SetVector<const CXXRecordDecl *> MostBases;
2328 
2329   std::function<void (const CXXRecordDecl *)> CollectMostBases;
2330   CollectMostBases = [&](const CXXRecordDecl *RD) {
2331     if (RD->getNumBases() == 0)
2332       MostBases.insert(RD);
2333     for (const CXXBaseSpecifier &B : RD->bases())
2334       CollectMostBases(B.getType()->getAsCXXRecordDecl());
2335   };
2336   CollectMostBases(RD);
2337   return MostBases.takeVector();
2338 }
2339 
2340 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
2341                                                            llvm::Function *F) {
2342   llvm::AttrBuilder B(F->getContext());
2343 
2344   if ((!D || !D->hasAttr<NoUwtableAttr>()) && CodeGenOpts.UnwindTables)
2345     B.addUWTableAttr(llvm::UWTableKind(CodeGenOpts.UnwindTables));
2346 
2347   if (CodeGenOpts.StackClashProtector)
2348     B.addAttribute("probe-stack", "inline-asm");
2349 
2350   if (CodeGenOpts.StackProbeSize && CodeGenOpts.StackProbeSize != 4096)
2351     B.addAttribute("stack-probe-size",
2352                    std::to_string(CodeGenOpts.StackProbeSize));
2353 
2354   if (!hasUnwindExceptions(LangOpts))
2355     B.addAttribute(llvm::Attribute::NoUnwind);
2356 
2357   if (D && D->hasAttr<NoStackProtectorAttr>())
2358     ; // Do nothing.
2359   else if (D && D->hasAttr<StrictGuardStackCheckAttr>() &&
2360            isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPOn))
2361     B.addAttribute(llvm::Attribute::StackProtectStrong);
2362   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPOn))
2363     B.addAttribute(llvm::Attribute::StackProtect);
2364   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPStrong))
2365     B.addAttribute(llvm::Attribute::StackProtectStrong);
2366   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq))
2367     B.addAttribute(llvm::Attribute::StackProtectReq);
2368 
2369   if (!D) {
2370     // If we don't have a declaration to control inlining, the function isn't
2371     // explicitly marked as alwaysinline for semantic reasons, and inlining is
2372     // disabled, mark the function as noinline.
2373     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline) &&
2374         CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining)
2375       B.addAttribute(llvm::Attribute::NoInline);
2376 
2377     F->addFnAttrs(B);
2378     return;
2379   }
2380 
2381   // Handle SME attributes that apply to function definitions,
2382   // rather than to function prototypes.
2383   if (D->hasAttr<ArmLocallyStreamingAttr>())
2384     B.addAttribute("aarch64_pstate_sm_body");
2385 
2386   if (auto *Attr = D->getAttr<ArmNewAttr>()) {
2387     if (Attr->isNewZA())
2388       B.addAttribute("aarch64_new_za");
2389     if (Attr->isNewZT0())
2390       B.addAttribute("aarch64_new_zt0");
2391   }
2392 
2393   // Track whether we need to add the optnone LLVM attribute,
2394   // starting with the default for this optimization level.
2395   bool ShouldAddOptNone =
2396       !CodeGenOpts.DisableO0ImplyOptNone && CodeGenOpts.OptimizationLevel == 0;
2397   // We can't add optnone in the following cases, it won't pass the verifier.
2398   ShouldAddOptNone &= !D->hasAttr<MinSizeAttr>();
2399   ShouldAddOptNone &= !D->hasAttr<AlwaysInlineAttr>();
2400 
2401   // Add optnone, but do so only if the function isn't always_inline.
2402   if ((ShouldAddOptNone || D->hasAttr<OptimizeNoneAttr>()) &&
2403       !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2404     B.addAttribute(llvm::Attribute::OptimizeNone);
2405 
2406     // OptimizeNone implies noinline; we should not be inlining such functions.
2407     B.addAttribute(llvm::Attribute::NoInline);
2408 
2409     // We still need to handle naked functions even though optnone subsumes
2410     // much of their semantics.
2411     if (D->hasAttr<NakedAttr>())
2412       B.addAttribute(llvm::Attribute::Naked);
2413 
2414     // OptimizeNone wins over OptimizeForSize and MinSize.
2415     F->removeFnAttr(llvm::Attribute::OptimizeForSize);
2416     F->removeFnAttr(llvm::Attribute::MinSize);
2417   } else if (D->hasAttr<NakedAttr>()) {
2418     // Naked implies noinline: we should not be inlining such functions.
2419     B.addAttribute(llvm::Attribute::Naked);
2420     B.addAttribute(llvm::Attribute::NoInline);
2421   } else if (D->hasAttr<NoDuplicateAttr>()) {
2422     B.addAttribute(llvm::Attribute::NoDuplicate);
2423   } else if (D->hasAttr<NoInlineAttr>() && !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2424     // Add noinline if the function isn't always_inline.
2425     B.addAttribute(llvm::Attribute::NoInline);
2426   } else if (D->hasAttr<AlwaysInlineAttr>() &&
2427              !F->hasFnAttribute(llvm::Attribute::NoInline)) {
2428     // (noinline wins over always_inline, and we can't specify both in IR)
2429     B.addAttribute(llvm::Attribute::AlwaysInline);
2430   } else if (CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining) {
2431     // If we're not inlining, then force everything that isn't always_inline to
2432     // carry an explicit noinline attribute.
2433     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline))
2434       B.addAttribute(llvm::Attribute::NoInline);
2435   } else {
2436     // Otherwise, propagate the inline hint attribute and potentially use its
2437     // absence to mark things as noinline.
2438     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
2439       // Search function and template pattern redeclarations for inline.
2440       auto CheckForInline = [](const FunctionDecl *FD) {
2441         auto CheckRedeclForInline = [](const FunctionDecl *Redecl) {
2442           return Redecl->isInlineSpecified();
2443         };
2444         if (any_of(FD->redecls(), CheckRedeclForInline))
2445           return true;
2446         const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern();
2447         if (!Pattern)
2448           return false;
2449         return any_of(Pattern->redecls(), CheckRedeclForInline);
2450       };
2451       if (CheckForInline(FD)) {
2452         B.addAttribute(llvm::Attribute::InlineHint);
2453       } else if (CodeGenOpts.getInlining() ==
2454                      CodeGenOptions::OnlyHintInlining &&
2455                  !FD->isInlined() &&
2456                  !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2457         B.addAttribute(llvm::Attribute::NoInline);
2458       }
2459     }
2460   }
2461 
2462   // Add other optimization related attributes if we are optimizing this
2463   // function.
2464   if (!D->hasAttr<OptimizeNoneAttr>()) {
2465     if (D->hasAttr<ColdAttr>()) {
2466       if (!ShouldAddOptNone)
2467         B.addAttribute(llvm::Attribute::OptimizeForSize);
2468       B.addAttribute(llvm::Attribute::Cold);
2469     }
2470     if (D->hasAttr<HotAttr>())
2471       B.addAttribute(llvm::Attribute::Hot);
2472     if (D->hasAttr<MinSizeAttr>())
2473       B.addAttribute(llvm::Attribute::MinSize);
2474   }
2475 
2476   F->addFnAttrs(B);
2477 
2478   unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
2479   if (alignment)
2480     F->setAlignment(llvm::Align(alignment));
2481 
2482   if (!D->hasAttr<AlignedAttr>())
2483     if (LangOpts.FunctionAlignment)
2484       F->setAlignment(llvm::Align(1ull << LangOpts.FunctionAlignment));
2485 
2486   // Some C++ ABIs require 2-byte alignment for member functions, in order to
2487   // reserve a bit for differentiating between virtual and non-virtual member
2488   // functions. If the current target's C++ ABI requires this and this is a
2489   // member function, set its alignment accordingly.
2490   if (getTarget().getCXXABI().areMemberFunctionsAligned()) {
2491     if (isa<CXXMethodDecl>(D) && F->getPointerAlignment(getDataLayout()) < 2)
2492       F->setAlignment(std::max(llvm::Align(2), F->getAlign().valueOrOne()));
2493   }
2494 
2495   // In the cross-dso CFI mode with canonical jump tables, we want !type
2496   // attributes on definitions only.
2497   if (CodeGenOpts.SanitizeCfiCrossDso &&
2498       CodeGenOpts.SanitizeCfiCanonicalJumpTables) {
2499     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
2500       // Skip available_externally functions. They won't be codegen'ed in the
2501       // current module anyway.
2502       if (getContext().GetGVALinkageForFunction(FD) != GVA_AvailableExternally)
2503         CreateFunctionTypeMetadataForIcall(FD, F);
2504     }
2505   }
2506 
2507   // Emit type metadata on member functions for member function pointer checks.
2508   // These are only ever necessary on definitions; we're guaranteed that the
2509   // definition will be present in the LTO unit as a result of LTO visibility.
2510   auto *MD = dyn_cast<CXXMethodDecl>(D);
2511   if (MD && requiresMemberFunctionPointerTypeMetadata(*this, MD)) {
2512     for (const CXXRecordDecl *Base : getMostBaseClasses(MD->getParent())) {
2513       llvm::Metadata *Id =
2514           CreateMetadataIdentifierForType(Context.getMemberPointerType(
2515               MD->getType(), Context.getRecordType(Base).getTypePtr()));
2516       F->addTypeMetadata(0, Id);
2517     }
2518   }
2519 }
2520 
2521 void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
2522   const Decl *D = GD.getDecl();
2523   if (isa_and_nonnull<NamedDecl>(D))
2524     setGVProperties(GV, GD);
2525   else
2526     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
2527 
2528   if (D && D->hasAttr<UsedAttr>())
2529     addUsedOrCompilerUsedGlobal(GV);
2530 
2531   if (const auto *VD = dyn_cast_if_present<VarDecl>(D);
2532       VD &&
2533       ((CodeGenOpts.KeepPersistentStorageVariables &&
2534         (VD->getStorageDuration() == SD_Static ||
2535          VD->getStorageDuration() == SD_Thread)) ||
2536        (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
2537         VD->getType().isConstQualified())))
2538     addUsedOrCompilerUsedGlobal(GV);
2539 }
2540 
2541 bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
2542                                                 llvm::AttrBuilder &Attrs,
2543                                                 bool SetTargetFeatures) {
2544   // Add target-cpu and target-features attributes to functions. If
2545   // we have a decl for the function and it has a target attribute then
2546   // parse that and add it to the feature set.
2547   StringRef TargetCPU = getTarget().getTargetOpts().CPU;
2548   StringRef TuneCPU = getTarget().getTargetOpts().TuneCPU;
2549   std::vector<std::string> Features;
2550   const auto *FD = dyn_cast_or_null<FunctionDecl>(GD.getDecl());
2551   FD = FD ? FD->getMostRecentDecl() : FD;
2552   const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
2553   const auto *TV = FD ? FD->getAttr<TargetVersionAttr>() : nullptr;
2554   assert((!TD || !TV) && "both target_version and target specified");
2555   const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
2556   const auto *TC = FD ? FD->getAttr<TargetClonesAttr>() : nullptr;
2557   bool AddedAttr = false;
2558   if (TD || TV || SD || TC) {
2559     llvm::StringMap<bool> FeatureMap;
2560     getContext().getFunctionFeatureMap(FeatureMap, GD);
2561 
2562     // Produce the canonical string for this set of features.
2563     for (const llvm::StringMap<bool>::value_type &Entry : FeatureMap)
2564       Features.push_back((Entry.getValue() ? "+" : "-") + Entry.getKey().str());
2565 
2566     // Now add the target-cpu and target-features to the function.
2567     // While we populated the feature map above, we still need to
2568     // get and parse the target attribute so we can get the cpu for
2569     // the function.
2570     if (TD) {
2571       ParsedTargetAttr ParsedAttr =
2572           Target.parseTargetAttr(TD->getFeaturesStr());
2573       if (!ParsedAttr.CPU.empty() &&
2574           getTarget().isValidCPUName(ParsedAttr.CPU)) {
2575         TargetCPU = ParsedAttr.CPU;
2576         TuneCPU = ""; // Clear the tune CPU.
2577       }
2578       if (!ParsedAttr.Tune.empty() &&
2579           getTarget().isValidCPUName(ParsedAttr.Tune))
2580         TuneCPU = ParsedAttr.Tune;
2581     }
2582 
2583     if (SD) {
2584       // Apply the given CPU name as the 'tune-cpu' so that the optimizer can
2585       // favor this processor.
2586       TuneCPU = SD->getCPUName(GD.getMultiVersionIndex())->getName();
2587     }
2588   } else {
2589     // Otherwise just add the existing target cpu and target features to the
2590     // function.
2591     Features = getTarget().getTargetOpts().Features;
2592   }
2593 
2594   if (!TargetCPU.empty()) {
2595     Attrs.addAttribute("target-cpu", TargetCPU);
2596     AddedAttr = true;
2597   }
2598   if (!TuneCPU.empty()) {
2599     Attrs.addAttribute("tune-cpu", TuneCPU);
2600     AddedAttr = true;
2601   }
2602   if (!Features.empty() && SetTargetFeatures) {
2603     llvm::erase_if(Features, [&](const std::string& F) {
2604        return getTarget().isReadOnlyFeature(F.substr(1));
2605     });
2606     llvm::sort(Features);
2607     Attrs.addAttribute("target-features", llvm::join(Features, ","));
2608     AddedAttr = true;
2609   }
2610 
2611   return AddedAttr;
2612 }
2613 
2614 void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
2615                                           llvm::GlobalObject *GO) {
2616   const Decl *D = GD.getDecl();
2617   SetCommonAttributes(GD, GO);
2618 
2619   if (D) {
2620     if (auto *GV = dyn_cast<llvm::GlobalVariable>(GO)) {
2621       if (D->hasAttr<RetainAttr>())
2622         addUsedGlobal(GV);
2623       if (auto *SA = D->getAttr<PragmaClangBSSSectionAttr>())
2624         GV->addAttribute("bss-section", SA->getName());
2625       if (auto *SA = D->getAttr<PragmaClangDataSectionAttr>())
2626         GV->addAttribute("data-section", SA->getName());
2627       if (auto *SA = D->getAttr<PragmaClangRodataSectionAttr>())
2628         GV->addAttribute("rodata-section", SA->getName());
2629       if (auto *SA = D->getAttr<PragmaClangRelroSectionAttr>())
2630         GV->addAttribute("relro-section", SA->getName());
2631     }
2632 
2633     if (auto *F = dyn_cast<llvm::Function>(GO)) {
2634       if (D->hasAttr<RetainAttr>())
2635         addUsedGlobal(F);
2636       if (auto *SA = D->getAttr<PragmaClangTextSectionAttr>())
2637         if (!D->getAttr<SectionAttr>())
2638           F->setSection(SA->getName());
2639 
2640       llvm::AttrBuilder Attrs(F->getContext());
2641       if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
2642         // We know that GetCPUAndFeaturesAttributes will always have the
2643         // newest set, since it has the newest possible FunctionDecl, so the
2644         // new ones should replace the old.
2645         llvm::AttributeMask RemoveAttrs;
2646         RemoveAttrs.addAttribute("target-cpu");
2647         RemoveAttrs.addAttribute("target-features");
2648         RemoveAttrs.addAttribute("tune-cpu");
2649         F->removeFnAttrs(RemoveAttrs);
2650         F->addFnAttrs(Attrs);
2651       }
2652     }
2653 
2654     if (const auto *CSA = D->getAttr<CodeSegAttr>())
2655       GO->setSection(CSA->getName());
2656     else if (const auto *SA = D->getAttr<SectionAttr>())
2657       GO->setSection(SA->getName());
2658   }
2659 
2660   getTargetCodeGenInfo().setTargetAttributes(D, GO, *this);
2661 }
2662 
2663 void CodeGenModule::SetInternalFunctionAttributes(GlobalDecl GD,
2664                                                   llvm::Function *F,
2665                                                   const CGFunctionInfo &FI) {
2666   const Decl *D = GD.getDecl();
2667   SetLLVMFunctionAttributes(GD, FI, F, /*IsThunk=*/false);
2668   SetLLVMFunctionAttributesForDefinition(D, F);
2669 
2670   F->setLinkage(llvm::Function::InternalLinkage);
2671 
2672   setNonAliasAttributes(GD, F);
2673 }
2674 
2675 static void setLinkageForGV(llvm::GlobalValue *GV, const NamedDecl *ND) {
2676   // Set linkage and visibility in case we never see a definition.
2677   LinkageInfo LV = ND->getLinkageAndVisibility();
2678   // Don't set internal linkage on declarations.
2679   // "extern_weak" is overloaded in LLVM; we probably should have
2680   // separate linkage types for this.
2681   if (isExternallyVisible(LV.getLinkage()) &&
2682       (ND->hasAttr<WeakAttr>() || ND->isWeakImported()))
2683     GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2684 }
2685 
2686 void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
2687                                                        llvm::Function *F) {
2688   // Only if we are checking indirect calls.
2689   if (!LangOpts.Sanitize.has(SanitizerKind::CFIICall))
2690     return;
2691 
2692   // Non-static class methods are handled via vtable or member function pointer
2693   // checks elsewhere.
2694   if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
2695     return;
2696 
2697   llvm::Metadata *MD = CreateMetadataIdentifierForType(FD->getType());
2698   F->addTypeMetadata(0, MD);
2699   F->addTypeMetadata(0, CreateMetadataIdentifierGeneralized(FD->getType()));
2700 
2701   // Emit a hash-based bit set entry for cross-DSO calls.
2702   if (CodeGenOpts.SanitizeCfiCrossDso)
2703     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
2704       F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
2705 }
2706 
2707 void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
2708   llvm::LLVMContext &Ctx = F->getContext();
2709   llvm::MDBuilder MDB(Ctx);
2710   F->setMetadata(llvm::LLVMContext::MD_kcfi_type,
2711                  llvm::MDNode::get(
2712                      Ctx, MDB.createConstant(CreateKCFITypeId(FD->getType()))));
2713 }
2714 
2715 static bool allowKCFIIdentifier(StringRef Name) {
2716   // KCFI type identifier constants are only necessary for external assembly
2717   // functions, which means it's safe to skip unusual names. Subset of
2718   // MCAsmInfo::isAcceptableChar() and MCAsmInfoXCOFF::isAcceptableChar().
2719   return llvm::all_of(Name, [](const char &C) {
2720     return llvm::isAlnum(C) || C == '_' || C == '.';
2721   });
2722 }
2723 
2724 void CodeGenModule::finalizeKCFITypes() {
2725   llvm::Module &M = getModule();
2726   for (auto &F : M.functions()) {
2727     // Remove KCFI type metadata from non-address-taken local functions.
2728     bool AddressTaken = F.hasAddressTaken();
2729     if (!AddressTaken && F.hasLocalLinkage())
2730       F.eraseMetadata(llvm::LLVMContext::MD_kcfi_type);
2731 
2732     // Generate a constant with the expected KCFI type identifier for all
2733     // address-taken function declarations to support annotating indirectly
2734     // called assembly functions.
2735     if (!AddressTaken || !F.isDeclaration())
2736       continue;
2737 
2738     const llvm::ConstantInt *Type;
2739     if (const llvm::MDNode *MD = F.getMetadata(llvm::LLVMContext::MD_kcfi_type))
2740       Type = llvm::mdconst::extract<llvm::ConstantInt>(MD->getOperand(0));
2741     else
2742       continue;
2743 
2744     StringRef Name = F.getName();
2745     if (!allowKCFIIdentifier(Name))
2746       continue;
2747 
2748     std::string Asm = (".weak __kcfi_typeid_" + Name + "\n.set __kcfi_typeid_" +
2749                        Name + ", " + Twine(Type->getZExtValue()) + "\n")
2750                           .str();
2751     M.appendModuleInlineAsm(Asm);
2752   }
2753 }
2754 
2755 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
2756                                           bool IsIncompleteFunction,
2757                                           bool IsThunk) {
2758 
2759   if (llvm::Intrinsic::ID IID = F->getIntrinsicID()) {
2760     // If this is an intrinsic function, set the function's attributes
2761     // to the intrinsic's attributes.
2762     F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), IID));
2763     return;
2764   }
2765 
2766   const auto *FD = cast<FunctionDecl>(GD.getDecl());
2767 
2768   if (!IsIncompleteFunction)
2769     SetLLVMFunctionAttributes(GD, getTypes().arrangeGlobalDeclaration(GD), F,
2770                               IsThunk);
2771 
2772   // Add the Returned attribute for "this", except for iOS 5 and earlier
2773   // where substantial code, including the libstdc++ dylib, was compiled with
2774   // GCC and does not actually return "this".
2775   if (!IsThunk && getCXXABI().HasThisReturn(GD) &&
2776       !(getTriple().isiOS() && getTriple().isOSVersionLT(6))) {
2777     assert(!F->arg_empty() &&
2778            F->arg_begin()->getType()
2779              ->canLosslesslyBitCastTo(F->getReturnType()) &&
2780            "unexpected this return");
2781     F->addParamAttr(0, llvm::Attribute::Returned);
2782   }
2783 
2784   // Only a few attributes are set on declarations; these may later be
2785   // overridden by a definition.
2786 
2787   setLinkageForGV(F, FD);
2788   setGVProperties(F, FD);
2789 
2790   // Setup target-specific attributes.
2791   if (!IsIncompleteFunction && F->isDeclaration())
2792     getTargetCodeGenInfo().setTargetAttributes(FD, F, *this);
2793 
2794   if (const auto *CSA = FD->getAttr<CodeSegAttr>())
2795     F->setSection(CSA->getName());
2796   else if (const auto *SA = FD->getAttr<SectionAttr>())
2797      F->setSection(SA->getName());
2798 
2799   if (const auto *EA = FD->getAttr<ErrorAttr>()) {
2800     if (EA->isError())
2801       F->addFnAttr("dontcall-error", EA->getUserDiagnostic());
2802     else if (EA->isWarning())
2803       F->addFnAttr("dontcall-warn", EA->getUserDiagnostic());
2804   }
2805 
2806   // If we plan on emitting this inline builtin, we can't treat it as a builtin.
2807   if (FD->isInlineBuiltinDeclaration()) {
2808     const FunctionDecl *FDBody;
2809     bool HasBody = FD->hasBody(FDBody);
2810     (void)HasBody;
2811     assert(HasBody && "Inline builtin declarations should always have an "
2812                       "available body!");
2813     if (shouldEmitFunction(FDBody))
2814       F->addFnAttr(llvm::Attribute::NoBuiltin);
2815   }
2816 
2817   if (FD->isReplaceableGlobalAllocationFunction()) {
2818     // A replaceable global allocation function does not act like a builtin by
2819     // default, only if it is invoked by a new-expression or delete-expression.
2820     F->addFnAttr(llvm::Attribute::NoBuiltin);
2821   }
2822 
2823   if (isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))
2824     F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2825   else if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
2826     if (MD->isVirtual())
2827       F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2828 
2829   // Don't emit entries for function declarations in the cross-DSO mode. This
2830   // is handled with better precision by the receiving DSO. But if jump tables
2831   // are non-canonical then we need type metadata in order to produce the local
2832   // jump table.
2833   if (!CodeGenOpts.SanitizeCfiCrossDso ||
2834       !CodeGenOpts.SanitizeCfiCanonicalJumpTables)
2835     CreateFunctionTypeMetadataForIcall(FD, F);
2836 
2837   if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
2838     setKCFIType(FD, F);
2839 
2840   if (getLangOpts().OpenMP && FD->hasAttr<OMPDeclareSimdDeclAttr>())
2841     getOpenMPRuntime().emitDeclareSimdFunction(FD, F);
2842 
2843   if (CodeGenOpts.InlineMaxStackSize != UINT_MAX)
2844     F->addFnAttr("inline-max-stacksize", llvm::utostr(CodeGenOpts.InlineMaxStackSize));
2845 
2846   if (const auto *CB = FD->getAttr<CallbackAttr>()) {
2847     // Annotate the callback behavior as metadata:
2848     //  - The callback callee (as argument number).
2849     //  - The callback payloads (as argument numbers).
2850     llvm::LLVMContext &Ctx = F->getContext();
2851     llvm::MDBuilder MDB(Ctx);
2852 
2853     // The payload indices are all but the first one in the encoding. The first
2854     // identifies the callback callee.
2855     int CalleeIdx = *CB->encoding_begin();
2856     ArrayRef<int> PayloadIndices(CB->encoding_begin() + 1, CB->encoding_end());
2857     F->addMetadata(llvm::LLVMContext::MD_callback,
2858                    *llvm::MDNode::get(Ctx, {MDB.createCallbackEncoding(
2859                                                CalleeIdx, PayloadIndices,
2860                                                /* VarArgsArePassed */ false)}));
2861   }
2862 }
2863 
2864 void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {
2865   assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
2866          "Only globals with definition can force usage.");
2867   LLVMUsed.emplace_back(GV);
2868 }
2869 
2870 void CodeGenModule::addCompilerUsedGlobal(llvm::GlobalValue *GV) {
2871   assert(!GV->isDeclaration() &&
2872          "Only globals with definition can force usage.");
2873   LLVMCompilerUsed.emplace_back(GV);
2874 }
2875 
2876 void CodeGenModule::addUsedOrCompilerUsedGlobal(llvm::GlobalValue *GV) {
2877   assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
2878          "Only globals with definition can force usage.");
2879   if (getTriple().isOSBinFormatELF())
2880     LLVMCompilerUsed.emplace_back(GV);
2881   else
2882     LLVMUsed.emplace_back(GV);
2883 }
2884 
2885 static void emitUsed(CodeGenModule &CGM, StringRef Name,
2886                      std::vector<llvm::WeakTrackingVH> &List) {
2887   // Don't create llvm.used if there is no need.
2888   if (List.empty())
2889     return;
2890 
2891   // Convert List to what ConstantArray needs.
2892   SmallVector<llvm::Constant*, 8> UsedArray;
2893   UsedArray.resize(List.size());
2894   for (unsigned i = 0, e = List.size(); i != e; ++i) {
2895     UsedArray[i] =
2896         llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
2897             cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
2898   }
2899 
2900   if (UsedArray.empty())
2901     return;
2902   llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
2903 
2904   auto *GV = new llvm::GlobalVariable(
2905       CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,
2906       llvm::ConstantArray::get(ATy, UsedArray), Name);
2907 
2908   GV->setSection("llvm.metadata");
2909 }
2910 
2911 void CodeGenModule::emitLLVMUsed() {
2912   emitUsed(*this, "llvm.used", LLVMUsed);
2913   emitUsed(*this, "llvm.compiler.used", LLVMCompilerUsed);
2914 }
2915 
2916 void CodeGenModule::AppendLinkerOptions(StringRef Opts) {
2917   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opts);
2918   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2919 }
2920 
2921 void CodeGenModule::AddDetectMismatch(StringRef Name, StringRef Value) {
2922   llvm::SmallString<32> Opt;
2923   getTargetCodeGenInfo().getDetectMismatchOption(Name, Value, Opt);
2924   if (Opt.empty())
2925     return;
2926   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2927   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2928 }
2929 
2930 void CodeGenModule::AddDependentLib(StringRef Lib) {
2931   auto &C = getLLVMContext();
2932   if (getTarget().getTriple().isOSBinFormatELF()) {
2933       ELFDependentLibraries.push_back(
2934         llvm::MDNode::get(C, llvm::MDString::get(C, Lib)));
2935     return;
2936   }
2937 
2938   llvm::SmallString<24> Opt;
2939   getTargetCodeGenInfo().getDependentLibraryOption(Lib, Opt);
2940   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2941   LinkerOptionsMetadata.push_back(llvm::MDNode::get(C, MDOpts));
2942 }
2943 
2944 /// Add link options implied by the given module, including modules
2945 /// it depends on, using a postorder walk.
2946 static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
2947                                     SmallVectorImpl<llvm::MDNode *> &Metadata,
2948                                     llvm::SmallPtrSet<Module *, 16> &Visited) {
2949   // Import this module's parent.
2950   if (Mod->Parent && Visited.insert(Mod->Parent).second) {
2951     addLinkOptionsPostorder(CGM, Mod->Parent, Metadata, Visited);
2952   }
2953 
2954   // Import this module's dependencies.
2955   for (Module *Import : llvm::reverse(Mod->Imports)) {
2956     if (Visited.insert(Import).second)
2957       addLinkOptionsPostorder(CGM, Import, Metadata, Visited);
2958   }
2959 
2960   // Add linker options to link against the libraries/frameworks
2961   // described by this module.
2962   llvm::LLVMContext &Context = CGM.getLLVMContext();
2963   bool IsELF = CGM.getTarget().getTriple().isOSBinFormatELF();
2964 
2965   // For modules that use export_as for linking, use that module
2966   // name instead.
2967   if (Mod->UseExportAsModuleLinkName)
2968     return;
2969 
2970   for (const Module::LinkLibrary &LL : llvm::reverse(Mod->LinkLibraries)) {
2971     // Link against a framework.  Frameworks are currently Darwin only, so we
2972     // don't to ask TargetCodeGenInfo for the spelling of the linker option.
2973     if (LL.IsFramework) {
2974       llvm::Metadata *Args[2] = {llvm::MDString::get(Context, "-framework"),
2975                                  llvm::MDString::get(Context, LL.Library)};
2976 
2977       Metadata.push_back(llvm::MDNode::get(Context, Args));
2978       continue;
2979     }
2980 
2981     // Link against a library.
2982     if (IsELF) {
2983       llvm::Metadata *Args[2] = {
2984           llvm::MDString::get(Context, "lib"),
2985           llvm::MDString::get(Context, LL.Library),
2986       };
2987       Metadata.push_back(llvm::MDNode::get(Context, Args));
2988     } else {
2989       llvm::SmallString<24> Opt;
2990       CGM.getTargetCodeGenInfo().getDependentLibraryOption(LL.Library, Opt);
2991       auto *OptString = llvm::MDString::get(Context, Opt);
2992       Metadata.push_back(llvm::MDNode::get(Context, OptString));
2993     }
2994   }
2995 }
2996 
2997 void CodeGenModule::EmitModuleInitializers(clang::Module *Primary) {
2998   assert(Primary->isNamedModuleUnit() &&
2999          "We should only emit module initializers for named modules.");
3000 
3001   // Emit the initializers in the order that sub-modules appear in the
3002   // source, first Global Module Fragments, if present.
3003   if (auto GMF = Primary->getGlobalModuleFragment()) {
3004     for (Decl *D : getContext().getModuleInitializers(GMF)) {
3005       if (isa<ImportDecl>(D))
3006         continue;
3007       assert(isa<VarDecl>(D) && "GMF initializer decl is not a var?");
3008       EmitTopLevelDecl(D);
3009     }
3010   }
3011   // Second any associated with the module, itself.
3012   for (Decl *D : getContext().getModuleInitializers(Primary)) {
3013     // Skip import decls, the inits for those are called explicitly.
3014     if (isa<ImportDecl>(D))
3015       continue;
3016     EmitTopLevelDecl(D);
3017   }
3018   // Third any associated with the Privat eMOdule Fragment, if present.
3019   if (auto PMF = Primary->getPrivateModuleFragment()) {
3020     for (Decl *D : getContext().getModuleInitializers(PMF)) {
3021       // Skip import decls, the inits for those are called explicitly.
3022       if (isa<ImportDecl>(D))
3023         continue;
3024       assert(isa<VarDecl>(D) && "PMF initializer decl is not a var?");
3025       EmitTopLevelDecl(D);
3026     }
3027   }
3028 }
3029 
3030 void CodeGenModule::EmitModuleLinkOptions() {
3031   // Collect the set of all of the modules we want to visit to emit link
3032   // options, which is essentially the imported modules and all of their
3033   // non-explicit child modules.
3034   llvm::SetVector<clang::Module *> LinkModules;
3035   llvm::SmallPtrSet<clang::Module *, 16> Visited;
3036   SmallVector<clang::Module *, 16> Stack;
3037 
3038   // Seed the stack with imported modules.
3039   for (Module *M : ImportedModules) {
3040     // Do not add any link flags when an implementation TU of a module imports
3041     // a header of that same module.
3042     if (M->getTopLevelModuleName() == getLangOpts().CurrentModule &&
3043         !getLangOpts().isCompilingModule())
3044       continue;
3045     if (Visited.insert(M).second)
3046       Stack.push_back(M);
3047   }
3048 
3049   // Find all of the modules to import, making a little effort to prune
3050   // non-leaf modules.
3051   while (!Stack.empty()) {
3052     clang::Module *Mod = Stack.pop_back_val();
3053 
3054     bool AnyChildren = false;
3055 
3056     // Visit the submodules of this module.
3057     for (const auto &SM : Mod->submodules()) {
3058       // Skip explicit children; they need to be explicitly imported to be
3059       // linked against.
3060       if (SM->IsExplicit)
3061         continue;
3062 
3063       if (Visited.insert(SM).second) {
3064         Stack.push_back(SM);
3065         AnyChildren = true;
3066       }
3067     }
3068 
3069     // We didn't find any children, so add this module to the list of
3070     // modules to link against.
3071     if (!AnyChildren) {
3072       LinkModules.insert(Mod);
3073     }
3074   }
3075 
3076   // Add link options for all of the imported modules in reverse topological
3077   // order.  We don't do anything to try to order import link flags with respect
3078   // to linker options inserted by things like #pragma comment().
3079   SmallVector<llvm::MDNode *, 16> MetadataArgs;
3080   Visited.clear();
3081   for (Module *M : LinkModules)
3082     if (Visited.insert(M).second)
3083       addLinkOptionsPostorder(*this, M, MetadataArgs, Visited);
3084   std::reverse(MetadataArgs.begin(), MetadataArgs.end());
3085   LinkerOptionsMetadata.append(MetadataArgs.begin(), MetadataArgs.end());
3086 
3087   // Add the linker options metadata flag.
3088   auto *NMD = getModule().getOrInsertNamedMetadata("llvm.linker.options");
3089   for (auto *MD : LinkerOptionsMetadata)
3090     NMD->addOperand(MD);
3091 }
3092 
3093 void CodeGenModule::EmitDeferred() {
3094   // Emit deferred declare target declarations.
3095   if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
3096     getOpenMPRuntime().emitDeferredTargetDecls();
3097 
3098   // Emit code for any potentially referenced deferred decls.  Since a
3099   // previously unused static decl may become used during the generation of code
3100   // for a static function, iterate until no changes are made.
3101 
3102   if (!DeferredVTables.empty()) {
3103     EmitDeferredVTables();
3104 
3105     // Emitting a vtable doesn't directly cause more vtables to
3106     // become deferred, although it can cause functions to be
3107     // emitted that then need those vtables.
3108     assert(DeferredVTables.empty());
3109   }
3110 
3111   // Emit CUDA/HIP static device variables referenced by host code only.
3112   // Note we should not clear CUDADeviceVarODRUsedByHost since it is still
3113   // needed for further handling.
3114   if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice)
3115     llvm::append_range(DeferredDeclsToEmit,
3116                        getContext().CUDADeviceVarODRUsedByHost);
3117 
3118   // Stop if we're out of both deferred vtables and deferred declarations.
3119   if (DeferredDeclsToEmit.empty())
3120     return;
3121 
3122   // Grab the list of decls to emit. If EmitGlobalDefinition schedules more
3123   // work, it will not interfere with this.
3124   std::vector<GlobalDecl> CurDeclsToEmit;
3125   CurDeclsToEmit.swap(DeferredDeclsToEmit);
3126 
3127   for (GlobalDecl &D : CurDeclsToEmit) {
3128     // We should call GetAddrOfGlobal with IsForDefinition set to true in order
3129     // to get GlobalValue with exactly the type we need, not something that
3130     // might had been created for another decl with the same mangled name but
3131     // different type.
3132     llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(
3133         GetAddrOfGlobal(D, ForDefinition));
3134 
3135     // In case of different address spaces, we may still get a cast, even with
3136     // IsForDefinition equal to true. Query mangled names table to get
3137     // GlobalValue.
3138     if (!GV)
3139       GV = GetGlobalValue(getMangledName(D));
3140 
3141     // Make sure GetGlobalValue returned non-null.
3142     assert(GV);
3143 
3144     // Check to see if we've already emitted this.  This is necessary
3145     // for a couple of reasons: first, decls can end up in the
3146     // deferred-decls queue multiple times, and second, decls can end
3147     // up with definitions in unusual ways (e.g. by an extern inline
3148     // function acquiring a strong function redefinition).  Just
3149     // ignore these cases.
3150     if (!GV->isDeclaration())
3151       continue;
3152 
3153     // If this is OpenMP, check if it is legal to emit this global normally.
3154     if (LangOpts.OpenMP && OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(D))
3155       continue;
3156 
3157     // Otherwise, emit the definition and move on to the next one.
3158     EmitGlobalDefinition(D, GV);
3159 
3160     // If we found out that we need to emit more decls, do that recursively.
3161     // This has the advantage that the decls are emitted in a DFS and related
3162     // ones are close together, which is convenient for testing.
3163     if (!DeferredVTables.empty() || !DeferredDeclsToEmit.empty()) {
3164       EmitDeferred();
3165       assert(DeferredVTables.empty() && DeferredDeclsToEmit.empty());
3166     }
3167   }
3168 }
3169 
3170 void CodeGenModule::EmitVTablesOpportunistically() {
3171   // Try to emit external vtables as available_externally if they have emitted
3172   // all inlined virtual functions.  It runs after EmitDeferred() and therefore
3173   // is not allowed to create new references to things that need to be emitted
3174   // lazily. Note that it also uses fact that we eagerly emitting RTTI.
3175 
3176   assert((OpportunisticVTables.empty() || shouldOpportunisticallyEmitVTables())
3177          && "Only emit opportunistic vtables with optimizations");
3178 
3179   for (const CXXRecordDecl *RD : OpportunisticVTables) {
3180     assert(getVTables().isVTableExternal(RD) &&
3181            "This queue should only contain external vtables");
3182     if (getCXXABI().canSpeculativelyEmitVTable(RD))
3183       VTables.GenerateClassData(RD);
3184   }
3185   OpportunisticVTables.clear();
3186 }
3187 
3188 void CodeGenModule::EmitGlobalAnnotations() {
3189   for (const auto& [MangledName, VD] : DeferredAnnotations) {
3190     llvm::GlobalValue *GV = GetGlobalValue(MangledName);
3191     if (GV)
3192       AddGlobalAnnotations(VD, GV);
3193   }
3194   DeferredAnnotations.clear();
3195 
3196   if (Annotations.empty())
3197     return;
3198 
3199   // Create a new global variable for the ConstantStruct in the Module.
3200   llvm::Constant *Array = llvm::ConstantArray::get(llvm::ArrayType::get(
3201     Annotations[0]->getType(), Annotations.size()), Annotations);
3202   auto *gv = new llvm::GlobalVariable(getModule(), Array->getType(), false,
3203                                       llvm::GlobalValue::AppendingLinkage,
3204                                       Array, "llvm.global.annotations");
3205   gv->setSection(AnnotationSection);
3206 }
3207 
3208 llvm::Constant *CodeGenModule::EmitAnnotationString(StringRef Str) {
3209   llvm::Constant *&AStr = AnnotationStrings[Str];
3210   if (AStr)
3211     return AStr;
3212 
3213   // Not found yet, create a new global.
3214   llvm::Constant *s = llvm::ConstantDataArray::getString(getLLVMContext(), Str);
3215   auto *gv = new llvm::GlobalVariable(
3216       getModule(), s->getType(), true, llvm::GlobalValue::PrivateLinkage, s,
3217       ".str", nullptr, llvm::GlobalValue::NotThreadLocal,
3218       ConstGlobalsPtrTy->getAddressSpace());
3219   gv->setSection(AnnotationSection);
3220   gv->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3221   AStr = gv;
3222   return gv;
3223 }
3224 
3225 llvm::Constant *CodeGenModule::EmitAnnotationUnit(SourceLocation Loc) {
3226   SourceManager &SM = getContext().getSourceManager();
3227   PresumedLoc PLoc = SM.getPresumedLoc(Loc);
3228   if (PLoc.isValid())
3229     return EmitAnnotationString(PLoc.getFilename());
3230   return EmitAnnotationString(SM.getBufferName(Loc));
3231 }
3232 
3233 llvm::Constant *CodeGenModule::EmitAnnotationLineNo(SourceLocation L) {
3234   SourceManager &SM = getContext().getSourceManager();
3235   PresumedLoc PLoc = SM.getPresumedLoc(L);
3236   unsigned LineNo = PLoc.isValid() ? PLoc.getLine() :
3237     SM.getExpansionLineNumber(L);
3238   return llvm::ConstantInt::get(Int32Ty, LineNo);
3239 }
3240 
3241 llvm::Constant *CodeGenModule::EmitAnnotationArgs(const AnnotateAttr *Attr) {
3242   ArrayRef<Expr *> Exprs = {Attr->args_begin(), Attr->args_size()};
3243   if (Exprs.empty())
3244     return llvm::ConstantPointerNull::get(ConstGlobalsPtrTy);
3245 
3246   llvm::FoldingSetNodeID ID;
3247   for (Expr *E : Exprs) {
3248     ID.Add(cast<clang::ConstantExpr>(E)->getAPValueResult());
3249   }
3250   llvm::Constant *&Lookup = AnnotationArgs[ID.ComputeHash()];
3251   if (Lookup)
3252     return Lookup;
3253 
3254   llvm::SmallVector<llvm::Constant *, 4> LLVMArgs;
3255   LLVMArgs.reserve(Exprs.size());
3256   ConstantEmitter ConstEmiter(*this);
3257   llvm::transform(Exprs, std::back_inserter(LLVMArgs), [&](const Expr *E) {
3258     const auto *CE = cast<clang::ConstantExpr>(E);
3259     return ConstEmiter.emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(),
3260                                     CE->getType());
3261   });
3262   auto *Struct = llvm::ConstantStruct::getAnon(LLVMArgs);
3263   auto *GV = new llvm::GlobalVariable(getModule(), Struct->getType(), true,
3264                                       llvm::GlobalValue::PrivateLinkage, Struct,
3265                                       ".args");
3266   GV->setSection(AnnotationSection);
3267   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3268 
3269   Lookup = GV;
3270   return GV;
3271 }
3272 
3273 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
3274                                                 const AnnotateAttr *AA,
3275                                                 SourceLocation L) {
3276   // Get the globals for file name, annotation, and the line number.
3277   llvm::Constant *AnnoGV = EmitAnnotationString(AA->getAnnotation()),
3278                  *UnitGV = EmitAnnotationUnit(L),
3279                  *LineNoCst = EmitAnnotationLineNo(L),
3280                  *Args = EmitAnnotationArgs(AA);
3281 
3282   llvm::Constant *GVInGlobalsAS = GV;
3283   if (GV->getAddressSpace() !=
3284       getDataLayout().getDefaultGlobalsAddressSpace()) {
3285     GVInGlobalsAS = llvm::ConstantExpr::getAddrSpaceCast(
3286         GV,
3287         llvm::PointerType::get(
3288             GV->getContext(), getDataLayout().getDefaultGlobalsAddressSpace()));
3289   }
3290 
3291   // Create the ConstantStruct for the global annotation.
3292   llvm::Constant *Fields[] = {
3293       GVInGlobalsAS, AnnoGV, UnitGV, LineNoCst, Args,
3294   };
3295   return llvm::ConstantStruct::getAnon(Fields);
3296 }
3297 
3298 void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D,
3299                                          llvm::GlobalValue *GV) {
3300   assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
3301   // Get the struct elements for these annotations.
3302   for (const auto *I : D->specific_attrs<AnnotateAttr>())
3303     Annotations.push_back(EmitAnnotateAttr(GV, I, D->getLocation()));
3304 }
3305 
3306 bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind, llvm::Function *Fn,
3307                                        SourceLocation Loc) const {
3308   const auto &NoSanitizeL = getContext().getNoSanitizeList();
3309   // NoSanitize by function name.
3310   if (NoSanitizeL.containsFunction(Kind, Fn->getName()))
3311     return true;
3312   // NoSanitize by location. Check "mainfile" prefix.
3313   auto &SM = Context.getSourceManager();
3314   FileEntryRef MainFile = *SM.getFileEntryRefForID(SM.getMainFileID());
3315   if (NoSanitizeL.containsMainFile(Kind, MainFile.getName()))
3316     return true;
3317 
3318   // Check "src" prefix.
3319   if (Loc.isValid())
3320     return NoSanitizeL.containsLocation(Kind, Loc);
3321   // If location is unknown, this may be a compiler-generated function. Assume
3322   // it's located in the main file.
3323   return NoSanitizeL.containsFile(Kind, MainFile.getName());
3324 }
3325 
3326 bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind,
3327                                        llvm::GlobalVariable *GV,
3328                                        SourceLocation Loc, QualType Ty,
3329                                        StringRef Category) const {
3330   const auto &NoSanitizeL = getContext().getNoSanitizeList();
3331   if (NoSanitizeL.containsGlobal(Kind, GV->getName(), Category))
3332     return true;
3333   auto &SM = Context.getSourceManager();
3334   if (NoSanitizeL.containsMainFile(
3335           Kind, SM.getFileEntryRefForID(SM.getMainFileID())->getName(),
3336           Category))
3337     return true;
3338   if (NoSanitizeL.containsLocation(Kind, Loc, Category))
3339     return true;
3340 
3341   // Check global type.
3342   if (!Ty.isNull()) {
3343     // Drill down the array types: if global variable of a fixed type is
3344     // not sanitized, we also don't instrument arrays of them.
3345     while (auto AT = dyn_cast<ArrayType>(Ty.getTypePtr()))
3346       Ty = AT->getElementType();
3347     Ty = Ty.getCanonicalType().getUnqualifiedType();
3348     // Only record types (classes, structs etc.) are ignored.
3349     if (Ty->isRecordType()) {
3350       std::string TypeStr = Ty.getAsString(getContext().getPrintingPolicy());
3351       if (NoSanitizeL.containsType(Kind, TypeStr, Category))
3352         return true;
3353     }
3354   }
3355   return false;
3356 }
3357 
3358 bool CodeGenModule::imbueXRayAttrs(llvm::Function *Fn, SourceLocation Loc,
3359                                    StringRef Category) const {
3360   const auto &XRayFilter = getContext().getXRayFilter();
3361   using ImbueAttr = XRayFunctionFilter::ImbueAttribute;
3362   auto Attr = ImbueAttr::NONE;
3363   if (Loc.isValid())
3364     Attr = XRayFilter.shouldImbueLocation(Loc, Category);
3365   if (Attr == ImbueAttr::NONE)
3366     Attr = XRayFilter.shouldImbueFunction(Fn->getName());
3367   switch (Attr) {
3368   case ImbueAttr::NONE:
3369     return false;
3370   case ImbueAttr::ALWAYS:
3371     Fn->addFnAttr("function-instrument", "xray-always");
3372     break;
3373   case ImbueAttr::ALWAYS_ARG1:
3374     Fn->addFnAttr("function-instrument", "xray-always");
3375     Fn->addFnAttr("xray-log-args", "1");
3376     break;
3377   case ImbueAttr::NEVER:
3378     Fn->addFnAttr("function-instrument", "xray-never");
3379     break;
3380   }
3381   return true;
3382 }
3383 
3384 ProfileList::ExclusionType
3385 CodeGenModule::isFunctionBlockedByProfileList(llvm::Function *Fn,
3386                                               SourceLocation Loc) const {
3387   const auto &ProfileList = getContext().getProfileList();
3388   // If the profile list is empty, then instrument everything.
3389   if (ProfileList.isEmpty())
3390     return ProfileList::Allow;
3391   CodeGenOptions::ProfileInstrKind Kind = getCodeGenOpts().getProfileInstr();
3392   // First, check the function name.
3393   if (auto V = ProfileList.isFunctionExcluded(Fn->getName(), Kind))
3394     return *V;
3395   // Next, check the source location.
3396   if (Loc.isValid())
3397     if (auto V = ProfileList.isLocationExcluded(Loc, Kind))
3398       return *V;
3399   // If location is unknown, this may be a compiler-generated function. Assume
3400   // it's located in the main file.
3401   auto &SM = Context.getSourceManager();
3402   if (auto MainFile = SM.getFileEntryRefForID(SM.getMainFileID()))
3403     if (auto V = ProfileList.isFileExcluded(MainFile->getName(), Kind))
3404       return *V;
3405   return ProfileList.getDefault(Kind);
3406 }
3407 
3408 ProfileList::ExclusionType
3409 CodeGenModule::isFunctionBlockedFromProfileInstr(llvm::Function *Fn,
3410                                                  SourceLocation Loc) const {
3411   auto V = isFunctionBlockedByProfileList(Fn, Loc);
3412   if (V != ProfileList::Allow)
3413     return V;
3414 
3415   auto NumGroups = getCodeGenOpts().ProfileTotalFunctionGroups;
3416   if (NumGroups > 1) {
3417     auto Group = llvm::crc32(arrayRefFromStringRef(Fn->getName())) % NumGroups;
3418     if (Group != getCodeGenOpts().ProfileSelectedFunctionGroup)
3419       return ProfileList::Skip;
3420   }
3421   return ProfileList::Allow;
3422 }
3423 
3424 bool CodeGenModule::MustBeEmitted(const ValueDecl *Global) {
3425   // Never defer when EmitAllDecls is specified.
3426   if (LangOpts.EmitAllDecls)
3427     return true;
3428 
3429   const auto *VD = dyn_cast<VarDecl>(Global);
3430   if (VD &&
3431       ((CodeGenOpts.KeepPersistentStorageVariables &&
3432         (VD->getStorageDuration() == SD_Static ||
3433          VD->getStorageDuration() == SD_Thread)) ||
3434        (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
3435         VD->getType().isConstQualified())))
3436     return true;
3437 
3438   return getContext().DeclMustBeEmitted(Global);
3439 }
3440 
3441 bool CodeGenModule::MayBeEmittedEagerly(const ValueDecl *Global) {
3442   // In OpenMP 5.0 variables and function may be marked as
3443   // device_type(host/nohost) and we should not emit them eagerly unless we sure
3444   // that they must be emitted on the host/device. To be sure we need to have
3445   // seen a declare target with an explicit mentioning of the function, we know
3446   // we have if the level of the declare target attribute is -1. Note that we
3447   // check somewhere else if we should emit this at all.
3448   if (LangOpts.OpenMP >= 50 && !LangOpts.OpenMPSimd) {
3449     std::optional<OMPDeclareTargetDeclAttr *> ActiveAttr =
3450         OMPDeclareTargetDeclAttr::getActiveAttr(Global);
3451     if (!ActiveAttr || (*ActiveAttr)->getLevel() != (unsigned)-1)
3452       return false;
3453   }
3454 
3455   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
3456     if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
3457       // Implicit template instantiations may change linkage if they are later
3458       // explicitly instantiated, so they should not be emitted eagerly.
3459       return false;
3460     // Defer until all versions have been semantically checked.
3461     if (FD->hasAttr<TargetVersionAttr>() && !FD->isMultiVersion())
3462       return false;
3463   }
3464   if (const auto *VD = dyn_cast<VarDecl>(Global)) {
3465     if (Context.getInlineVariableDefinitionKind(VD) ==
3466         ASTContext::InlineVariableDefinitionKind::WeakUnknown)
3467       // A definition of an inline constexpr static data member may change
3468       // linkage later if it's redeclared outside the class.
3469       return false;
3470     if (CXX20ModuleInits && VD->getOwningModule() &&
3471         !VD->getOwningModule()->isModuleMapModule()) {
3472       // For CXX20, module-owned initializers need to be deferred, since it is
3473       // not known at this point if they will be run for the current module or
3474       // as part of the initializer for an imported one.
3475       return false;
3476     }
3477   }
3478   // If OpenMP is enabled and threadprivates must be generated like TLS, delay
3479   // codegen for global variables, because they may be marked as threadprivate.
3480   if (LangOpts.OpenMP && LangOpts.OpenMPUseTLS &&
3481       getContext().getTargetInfo().isTLSSupported() && isa<VarDecl>(Global) &&
3482       !Global->getType().isConstantStorage(getContext(), false, false) &&
3483       !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(Global))
3484     return false;
3485 
3486   return true;
3487 }
3488 
3489 ConstantAddress CodeGenModule::GetAddrOfMSGuidDecl(const MSGuidDecl *GD) {
3490   StringRef Name = getMangledName(GD);
3491 
3492   // The UUID descriptor should be pointer aligned.
3493   CharUnits Alignment = CharUnits::fromQuantity(PointerAlignInBytes);
3494 
3495   // Look for an existing global.
3496   if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
3497     return ConstantAddress(GV, GV->getValueType(), Alignment);
3498 
3499   ConstantEmitter Emitter(*this);
3500   llvm::Constant *Init;
3501 
3502   APValue &V = GD->getAsAPValue();
3503   if (!V.isAbsent()) {
3504     // If possible, emit the APValue version of the initializer. In particular,
3505     // this gets the type of the constant right.
3506     Init = Emitter.emitForInitializer(
3507         GD->getAsAPValue(), GD->getType().getAddressSpace(), GD->getType());
3508   } else {
3509     // As a fallback, directly construct the constant.
3510     // FIXME: This may get padding wrong under esoteric struct layout rules.
3511     // MSVC appears to create a complete type 'struct __s_GUID' that it
3512     // presumably uses to represent these constants.
3513     MSGuidDecl::Parts Parts = GD->getParts();
3514     llvm::Constant *Fields[4] = {
3515         llvm::ConstantInt::get(Int32Ty, Parts.Part1),
3516         llvm::ConstantInt::get(Int16Ty, Parts.Part2),
3517         llvm::ConstantInt::get(Int16Ty, Parts.Part3),
3518         llvm::ConstantDataArray::getRaw(
3519             StringRef(reinterpret_cast<char *>(Parts.Part4And5), 8), 8,
3520             Int8Ty)};
3521     Init = llvm::ConstantStruct::getAnon(Fields);
3522   }
3523 
3524   auto *GV = new llvm::GlobalVariable(
3525       getModule(), Init->getType(),
3526       /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
3527   if (supportsCOMDAT())
3528     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
3529   setDSOLocal(GV);
3530 
3531   if (!V.isAbsent()) {
3532     Emitter.finalize(GV);
3533     return ConstantAddress(GV, GV->getValueType(), Alignment);
3534   }
3535 
3536   llvm::Type *Ty = getTypes().ConvertTypeForMem(GD->getType());
3537   return ConstantAddress(GV, Ty, Alignment);
3538 }
3539 
3540 ConstantAddress CodeGenModule::GetAddrOfUnnamedGlobalConstantDecl(
3541     const UnnamedGlobalConstantDecl *GCD) {
3542   CharUnits Alignment = getContext().getTypeAlignInChars(GCD->getType());
3543 
3544   llvm::GlobalVariable **Entry = nullptr;
3545   Entry = &UnnamedGlobalConstantDeclMap[GCD];
3546   if (*Entry)
3547     return ConstantAddress(*Entry, (*Entry)->getValueType(), Alignment);
3548 
3549   ConstantEmitter Emitter(*this);
3550   llvm::Constant *Init;
3551 
3552   const APValue &V = GCD->getValue();
3553 
3554   assert(!V.isAbsent());
3555   Init = Emitter.emitForInitializer(V, GCD->getType().getAddressSpace(),
3556                                     GCD->getType());
3557 
3558   auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
3559                                       /*isConstant=*/true,
3560                                       llvm::GlobalValue::PrivateLinkage, Init,
3561                                       ".constant");
3562   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3563   GV->setAlignment(Alignment.getAsAlign());
3564 
3565   Emitter.finalize(GV);
3566 
3567   *Entry = GV;
3568   return ConstantAddress(GV, GV->getValueType(), Alignment);
3569 }
3570 
3571 ConstantAddress CodeGenModule::GetAddrOfTemplateParamObject(
3572     const TemplateParamObjectDecl *TPO) {
3573   StringRef Name = getMangledName(TPO);
3574   CharUnits Alignment = getNaturalTypeAlignment(TPO->getType());
3575 
3576   if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
3577     return ConstantAddress(GV, GV->getValueType(), Alignment);
3578 
3579   ConstantEmitter Emitter(*this);
3580   llvm::Constant *Init = Emitter.emitForInitializer(
3581         TPO->getValue(), TPO->getType().getAddressSpace(), TPO->getType());
3582 
3583   if (!Init) {
3584     ErrorUnsupported(TPO, "template parameter object");
3585     return ConstantAddress::invalid();
3586   }
3587 
3588   llvm::GlobalValue::LinkageTypes Linkage =
3589       isExternallyVisible(TPO->getLinkageAndVisibility().getLinkage())
3590           ? llvm::GlobalValue::LinkOnceODRLinkage
3591           : llvm::GlobalValue::InternalLinkage;
3592   auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
3593                                       /*isConstant=*/true, Linkage, Init, Name);
3594   setGVProperties(GV, TPO);
3595   if (supportsCOMDAT())
3596     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
3597   Emitter.finalize(GV);
3598 
3599     return ConstantAddress(GV, GV->getValueType(), Alignment);
3600 }
3601 
3602 ConstantAddress CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
3603   const AliasAttr *AA = VD->getAttr<AliasAttr>();
3604   assert(AA && "No alias?");
3605 
3606   CharUnits Alignment = getContext().getDeclAlign(VD);
3607   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
3608 
3609   // See if there is already something with the target's name in the module.
3610   llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
3611   if (Entry)
3612     return ConstantAddress(Entry, DeclTy, Alignment);
3613 
3614   llvm::Constant *Aliasee;
3615   if (isa<llvm::FunctionType>(DeclTy))
3616     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy,
3617                                       GlobalDecl(cast<FunctionDecl>(VD)),
3618                                       /*ForVTable=*/false);
3619   else
3620     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), DeclTy, LangAS::Default,
3621                                     nullptr);
3622 
3623   auto *F = cast<llvm::GlobalValue>(Aliasee);
3624   F->setLinkage(llvm::Function::ExternalWeakLinkage);
3625   WeakRefReferences.insert(F);
3626 
3627   return ConstantAddress(Aliasee, DeclTy, Alignment);
3628 }
3629 
3630 template <typename AttrT> static bool hasImplicitAttr(const ValueDecl *D) {
3631   if (!D)
3632     return false;
3633   if (auto *A = D->getAttr<AttrT>())
3634     return A->isImplicit();
3635   return D->isImplicit();
3636 }
3637 
3638 void CodeGenModule::EmitGlobal(GlobalDecl GD) {
3639   const auto *Global = cast<ValueDecl>(GD.getDecl());
3640 
3641   // Weak references don't produce any output by themselves.
3642   if (Global->hasAttr<WeakRefAttr>())
3643     return;
3644 
3645   // If this is an alias definition (which otherwise looks like a declaration)
3646   // emit it now.
3647   if (Global->hasAttr<AliasAttr>())
3648     return EmitAliasDefinition(GD);
3649 
3650   // IFunc like an alias whose value is resolved at runtime by calling resolver.
3651   if (Global->hasAttr<IFuncAttr>())
3652     return emitIFuncDefinition(GD);
3653 
3654   // If this is a cpu_dispatch multiversion function, emit the resolver.
3655   if (Global->hasAttr<CPUDispatchAttr>())
3656     return emitCPUDispatchDefinition(GD);
3657 
3658   // If this is CUDA, be selective about which declarations we emit.
3659   // Non-constexpr non-lambda implicit host device functions are not emitted
3660   // unless they are used on device side.
3661   if (LangOpts.CUDA) {
3662     if (LangOpts.CUDAIsDevice) {
3663       const auto *FD = dyn_cast<FunctionDecl>(Global);
3664       if ((!Global->hasAttr<CUDADeviceAttr>() ||
3665            (LangOpts.OffloadImplicitHostDeviceTemplates && FD &&
3666             hasImplicitAttr<CUDAHostAttr>(FD) &&
3667             hasImplicitAttr<CUDADeviceAttr>(FD) && !FD->isConstexpr() &&
3668             !isLambdaCallOperator(FD) &&
3669             !getContext().CUDAImplicitHostDeviceFunUsedByDevice.count(FD))) &&
3670           !Global->hasAttr<CUDAGlobalAttr>() &&
3671           !Global->hasAttr<CUDAConstantAttr>() &&
3672           !Global->hasAttr<CUDASharedAttr>() &&
3673           !Global->getType()->isCUDADeviceBuiltinSurfaceType() &&
3674           !Global->getType()->isCUDADeviceBuiltinTextureType() &&
3675           !(LangOpts.HIPStdPar && isa<FunctionDecl>(Global) &&
3676             !Global->hasAttr<CUDAHostAttr>()))
3677         return;
3678     } else {
3679       // We need to emit host-side 'shadows' for all global
3680       // device-side variables because the CUDA runtime needs their
3681       // size and host-side address in order to provide access to
3682       // their device-side incarnations.
3683 
3684       // So device-only functions are the only things we skip.
3685       if (isa<FunctionDecl>(Global) && !Global->hasAttr<CUDAHostAttr>() &&
3686           Global->hasAttr<CUDADeviceAttr>())
3687         return;
3688 
3689       assert((isa<FunctionDecl>(Global) || isa<VarDecl>(Global)) &&
3690              "Expected Variable or Function");
3691     }
3692   }
3693 
3694   if (LangOpts.OpenMP) {
3695     // If this is OpenMP, check if it is legal to emit this global normally.
3696     if (OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(GD))
3697       return;
3698     if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Global)) {
3699       if (MustBeEmitted(Global))
3700         EmitOMPDeclareReduction(DRD);
3701       return;
3702     }
3703     if (auto *DMD = dyn_cast<OMPDeclareMapperDecl>(Global)) {
3704       if (MustBeEmitted(Global))
3705         EmitOMPDeclareMapper(DMD);
3706       return;
3707     }
3708   }
3709 
3710   // Ignore declarations, they will be emitted on their first use.
3711   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
3712     // Update deferred annotations with the latest declaration if the function
3713     // function was already used or defined.
3714     if (FD->hasAttr<AnnotateAttr>()) {
3715       StringRef MangledName = getMangledName(GD);
3716       if (GetGlobalValue(MangledName))
3717         DeferredAnnotations[MangledName] = FD;
3718     }
3719 
3720     // Forward declarations are emitted lazily on first use.
3721     if (!FD->doesThisDeclarationHaveABody()) {
3722       if (!FD->doesDeclarationForceExternallyVisibleDefinition() &&
3723           (!FD->isMultiVersion() ||
3724            !FD->getASTContext().getTargetInfo().getTriple().isAArch64()))
3725         return;
3726 
3727       StringRef MangledName = getMangledName(GD);
3728 
3729       // Compute the function info and LLVM type.
3730       const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
3731       llvm::Type *Ty = getTypes().GetFunctionType(FI);
3732 
3733       GetOrCreateLLVMFunction(MangledName, Ty, GD, /*ForVTable=*/false,
3734                               /*DontDefer=*/false);
3735       return;
3736     }
3737   } else {
3738     const auto *VD = cast<VarDecl>(Global);
3739     assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
3740     if (VD->isThisDeclarationADefinition() != VarDecl::Definition &&
3741         !Context.isMSStaticDataMemberInlineDefinition(VD)) {
3742       if (LangOpts.OpenMP) {
3743         // Emit declaration of the must-be-emitted declare target variable.
3744         if (std::optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
3745                 OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD)) {
3746 
3747           // If this variable has external storage and doesn't require special
3748           // link handling we defer to its canonical definition.
3749           if (VD->hasExternalStorage() &&
3750               Res != OMPDeclareTargetDeclAttr::MT_Link)
3751             return;
3752 
3753           bool UnifiedMemoryEnabled =
3754               getOpenMPRuntime().hasRequiresUnifiedSharedMemory();
3755           if ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
3756                *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
3757               !UnifiedMemoryEnabled) {
3758             (void)GetAddrOfGlobalVar(VD);
3759           } else {
3760             assert(((*Res == OMPDeclareTargetDeclAttr::MT_Link) ||
3761                     ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
3762                       *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
3763                      UnifiedMemoryEnabled)) &&
3764                    "Link clause or to clause with unified memory expected.");
3765             (void)getOpenMPRuntime().getAddrOfDeclareTargetVar(VD);
3766           }
3767 
3768           return;
3769         }
3770       }
3771       // If this declaration may have caused an inline variable definition to
3772       // change linkage, make sure that it's emitted.
3773       if (Context.getInlineVariableDefinitionKind(VD) ==
3774           ASTContext::InlineVariableDefinitionKind::Strong)
3775         GetAddrOfGlobalVar(VD);
3776       return;
3777     }
3778   }
3779 
3780   // Defer code generation to first use when possible, e.g. if this is an inline
3781   // function. If the global must always be emitted, do it eagerly if possible
3782   // to benefit from cache locality.
3783   if (MustBeEmitted(Global) && MayBeEmittedEagerly(Global)) {
3784     // Emit the definition if it can't be deferred.
3785     EmitGlobalDefinition(GD);
3786     addEmittedDeferredDecl(GD);
3787     return;
3788   }
3789 
3790   // If we're deferring emission of a C++ variable with an
3791   // initializer, remember the order in which it appeared in the file.
3792   if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) &&
3793       cast<VarDecl>(Global)->hasInit()) {
3794     DelayedCXXInitPosition[Global] = CXXGlobalInits.size();
3795     CXXGlobalInits.push_back(nullptr);
3796   }
3797 
3798   StringRef MangledName = getMangledName(GD);
3799   if (GetGlobalValue(MangledName) != nullptr) {
3800     // The value has already been used and should therefore be emitted.
3801     addDeferredDeclToEmit(GD);
3802   } else if (MustBeEmitted(Global)) {
3803     // The value must be emitted, but cannot be emitted eagerly.
3804     assert(!MayBeEmittedEagerly(Global));
3805     addDeferredDeclToEmit(GD);
3806   } else {
3807     // Otherwise, remember that we saw a deferred decl with this name.  The
3808     // first use of the mangled name will cause it to move into
3809     // DeferredDeclsToEmit.
3810     DeferredDecls[MangledName] = GD;
3811   }
3812 }
3813 
3814 // Check if T is a class type with a destructor that's not dllimport.
3815 static bool HasNonDllImportDtor(QualType T) {
3816   if (const auto *RT = T->getBaseElementTypeUnsafe()->getAs<RecordType>())
3817     if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
3818       if (RD->getDestructor() && !RD->getDestructor()->hasAttr<DLLImportAttr>())
3819         return true;
3820 
3821   return false;
3822 }
3823 
3824 namespace {
3825   struct FunctionIsDirectlyRecursive
3826       : public ConstStmtVisitor<FunctionIsDirectlyRecursive, bool> {
3827     const StringRef Name;
3828     const Builtin::Context &BI;
3829     FunctionIsDirectlyRecursive(StringRef N, const Builtin::Context &C)
3830         : Name(N), BI(C) {}
3831 
3832     bool VisitCallExpr(const CallExpr *E) {
3833       const FunctionDecl *FD = E->getDirectCallee();
3834       if (!FD)
3835         return false;
3836       AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
3837       if (Attr && Name == Attr->getLabel())
3838         return true;
3839       unsigned BuiltinID = FD->getBuiltinID();
3840       if (!BuiltinID || !BI.isLibFunction(BuiltinID))
3841         return false;
3842       StringRef BuiltinName = BI.getName(BuiltinID);
3843       if (BuiltinName.starts_with("__builtin_") &&
3844           Name == BuiltinName.slice(strlen("__builtin_"), StringRef::npos)) {
3845         return true;
3846       }
3847       return false;
3848     }
3849 
3850     bool VisitStmt(const Stmt *S) {
3851       for (const Stmt *Child : S->children())
3852         if (Child && this->Visit(Child))
3853           return true;
3854       return false;
3855     }
3856   };
3857 
3858   // Make sure we're not referencing non-imported vars or functions.
3859   struct DLLImportFunctionVisitor
3860       : public RecursiveASTVisitor<DLLImportFunctionVisitor> {
3861     bool SafeToInline = true;
3862 
3863     bool shouldVisitImplicitCode() const { return true; }
3864 
3865     bool VisitVarDecl(VarDecl *VD) {
3866       if (VD->getTLSKind()) {
3867         // A thread-local variable cannot be imported.
3868         SafeToInline = false;
3869         return SafeToInline;
3870       }
3871 
3872       // A variable definition might imply a destructor call.
3873       if (VD->isThisDeclarationADefinition())
3874         SafeToInline = !HasNonDllImportDtor(VD->getType());
3875 
3876       return SafeToInline;
3877     }
3878 
3879     bool VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
3880       if (const auto *D = E->getTemporary()->getDestructor())
3881         SafeToInline = D->hasAttr<DLLImportAttr>();
3882       return SafeToInline;
3883     }
3884 
3885     bool VisitDeclRefExpr(DeclRefExpr *E) {
3886       ValueDecl *VD = E->getDecl();
3887       if (isa<FunctionDecl>(VD))
3888         SafeToInline = VD->hasAttr<DLLImportAttr>();
3889       else if (VarDecl *V = dyn_cast<VarDecl>(VD))
3890         SafeToInline = !V->hasGlobalStorage() || V->hasAttr<DLLImportAttr>();
3891       return SafeToInline;
3892     }
3893 
3894     bool VisitCXXConstructExpr(CXXConstructExpr *E) {
3895       SafeToInline = E->getConstructor()->hasAttr<DLLImportAttr>();
3896       return SafeToInline;
3897     }
3898 
3899     bool VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
3900       CXXMethodDecl *M = E->getMethodDecl();
3901       if (!M) {
3902         // Call through a pointer to member function. This is safe to inline.
3903         SafeToInline = true;
3904       } else {
3905         SafeToInline = M->hasAttr<DLLImportAttr>();
3906       }
3907       return SafeToInline;
3908     }
3909 
3910     bool VisitCXXDeleteExpr(CXXDeleteExpr *E) {
3911       SafeToInline = E->getOperatorDelete()->hasAttr<DLLImportAttr>();
3912       return SafeToInline;
3913     }
3914 
3915     bool VisitCXXNewExpr(CXXNewExpr *E) {
3916       SafeToInline = E->getOperatorNew()->hasAttr<DLLImportAttr>();
3917       return SafeToInline;
3918     }
3919   };
3920 }
3921 
3922 // isTriviallyRecursive - Check if this function calls another
3923 // decl that, because of the asm attribute or the other decl being a builtin,
3924 // ends up pointing to itself.
3925 bool
3926 CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) {
3927   StringRef Name;
3928   if (getCXXABI().getMangleContext().shouldMangleDeclName(FD)) {
3929     // asm labels are a special kind of mangling we have to support.
3930     AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
3931     if (!Attr)
3932       return false;
3933     Name = Attr->getLabel();
3934   } else {
3935     Name = FD->getName();
3936   }
3937 
3938   FunctionIsDirectlyRecursive Walker(Name, Context.BuiltinInfo);
3939   const Stmt *Body = FD->getBody();
3940   return Body ? Walker.Visit(Body) : false;
3941 }
3942 
3943 bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
3944   if (getFunctionLinkage(GD) != llvm::Function::AvailableExternallyLinkage)
3945     return true;
3946 
3947   const auto *F = cast<FunctionDecl>(GD.getDecl());
3948   if (CodeGenOpts.OptimizationLevel == 0 && !F->hasAttr<AlwaysInlineAttr>())
3949     return false;
3950 
3951   // We don't import function bodies from other named module units since that
3952   // behavior may break ABI compatibility of the current unit.
3953   if (const Module *M = F->getOwningModule();
3954       M && M->getTopLevelModule()->isNamedModule() &&
3955       getContext().getCurrentNamedModule() != M->getTopLevelModule() &&
3956       !F->hasAttr<AlwaysInlineAttr>())
3957     return false;
3958 
3959   if (F->hasAttr<NoInlineAttr>())
3960     return false;
3961 
3962   if (F->hasAttr<DLLImportAttr>() && !F->hasAttr<AlwaysInlineAttr>()) {
3963     // Check whether it would be safe to inline this dllimport function.
3964     DLLImportFunctionVisitor Visitor;
3965     Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
3966     if (!Visitor.SafeToInline)
3967       return false;
3968 
3969     if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(F)) {
3970       // Implicit destructor invocations aren't captured in the AST, so the
3971       // check above can't see them. Check for them manually here.
3972       for (const Decl *Member : Dtor->getParent()->decls())
3973         if (isa<FieldDecl>(Member))
3974           if (HasNonDllImportDtor(cast<FieldDecl>(Member)->getType()))
3975             return false;
3976       for (const CXXBaseSpecifier &B : Dtor->getParent()->bases())
3977         if (HasNonDllImportDtor(B.getType()))
3978           return false;
3979     }
3980   }
3981 
3982   // Inline builtins declaration must be emitted. They often are fortified
3983   // functions.
3984   if (F->isInlineBuiltinDeclaration())
3985     return true;
3986 
3987   // PR9614. Avoid cases where the source code is lying to us. An available
3988   // externally function should have an equivalent function somewhere else,
3989   // but a function that calls itself through asm label/`__builtin_` trickery is
3990   // clearly not equivalent to the real implementation.
3991   // This happens in glibc's btowc and in some configure checks.
3992   return !isTriviallyRecursive(F);
3993 }
3994 
3995 bool CodeGenModule::shouldOpportunisticallyEmitVTables() {
3996   return CodeGenOpts.OptimizationLevel > 0;
3997 }
3998 
3999 void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
4000                                                        llvm::GlobalValue *GV) {
4001   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4002 
4003   if (FD->isCPUSpecificMultiVersion()) {
4004     auto *Spec = FD->getAttr<CPUSpecificAttr>();
4005     for (unsigned I = 0; I < Spec->cpus_size(); ++I)
4006       EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
4007   } else if (auto *TC = FD->getAttr<TargetClonesAttr>()) {
4008     for (unsigned I = 0; I < TC->featuresStrs_size(); ++I)
4009       // AArch64 favors the default target version over the clone if any.
4010       if ((!TC->isDefaultVersion(I) || !getTarget().getTriple().isAArch64()) &&
4011           TC->isFirstOfVersion(I))
4012         EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
4013     // Ensure that the resolver function is also emitted.
4014     GetOrCreateMultiVersionResolver(GD);
4015   } else
4016     EmitGlobalFunctionDefinition(GD, GV);
4017 
4018   // Defer the resolver emission until we can reason whether the TU
4019   // contains a default target version implementation.
4020   if (FD->isTargetVersionMultiVersion())
4021     AddDeferredMultiVersionResolverToEmit(GD);
4022 }
4023 
4024 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
4025   const auto *D = cast<ValueDecl>(GD.getDecl());
4026 
4027   PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
4028                                  Context.getSourceManager(),
4029                                  "Generating code for declaration");
4030 
4031   if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
4032     // At -O0, don't generate IR for functions with available_externally
4033     // linkage.
4034     if (!shouldEmitFunction(GD))
4035       return;
4036 
4037     llvm::TimeTraceScope TimeScope("CodeGen Function", [&]() {
4038       std::string Name;
4039       llvm::raw_string_ostream OS(Name);
4040       FD->getNameForDiagnostic(OS, getContext().getPrintingPolicy(),
4041                                /*Qualified=*/true);
4042       return Name;
4043     });
4044 
4045     if (const auto *Method = dyn_cast<CXXMethodDecl>(D)) {
4046       // Make sure to emit the definition(s) before we emit the thunks.
4047       // This is necessary for the generation of certain thunks.
4048       if (isa<CXXConstructorDecl>(Method) || isa<CXXDestructorDecl>(Method))
4049         ABI->emitCXXStructor(GD);
4050       else if (FD->isMultiVersion())
4051         EmitMultiVersionFunctionDefinition(GD, GV);
4052       else
4053         EmitGlobalFunctionDefinition(GD, GV);
4054 
4055       if (Method->isVirtual())
4056         getVTables().EmitThunks(GD);
4057 
4058       return;
4059     }
4060 
4061     if (FD->isMultiVersion())
4062       return EmitMultiVersionFunctionDefinition(GD, GV);
4063     return EmitGlobalFunctionDefinition(GD, GV);
4064   }
4065 
4066   if (const auto *VD = dyn_cast<VarDecl>(D))
4067     return EmitGlobalVarDefinition(VD, !VD->hasDefinition());
4068 
4069   llvm_unreachable("Invalid argument to EmitGlobalDefinition()");
4070 }
4071 
4072 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
4073                                                       llvm::Function *NewFn);
4074 
4075 static unsigned
4076 TargetMVPriority(const TargetInfo &TI,
4077                  const CodeGenFunction::MultiVersionResolverOption &RO) {
4078   unsigned Priority = 0;
4079   unsigned NumFeatures = 0;
4080   for (StringRef Feat : RO.Conditions.Features) {
4081     Priority = std::max(Priority, TI.multiVersionSortPriority(Feat));
4082     NumFeatures++;
4083   }
4084 
4085   if (!RO.Conditions.Architecture.empty())
4086     Priority = std::max(
4087         Priority, TI.multiVersionSortPriority(RO.Conditions.Architecture));
4088 
4089   Priority += TI.multiVersionFeatureCost() * NumFeatures;
4090 
4091   return Priority;
4092 }
4093 
4094 // Multiversion functions should be at most 'WeakODRLinkage' so that a different
4095 // TU can forward declare the function without causing problems.  Particularly
4096 // in the cases of CPUDispatch, this causes issues. This also makes sure we
4097 // work with internal linkage functions, so that the same function name can be
4098 // used with internal linkage in multiple TUs.
4099 llvm::GlobalValue::LinkageTypes getMultiversionLinkage(CodeGenModule &CGM,
4100                                                        GlobalDecl GD) {
4101   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
4102   if (FD->getFormalLinkage() == Linkage::Internal)
4103     return llvm::GlobalValue::InternalLinkage;
4104   return llvm::GlobalValue::WeakODRLinkage;
4105 }
4106 
4107 static FunctionDecl *createDefaultTargetVersionFrom(const FunctionDecl *FD) {
4108   DeclContext *DeclCtx = FD->getASTContext().getTranslationUnitDecl();
4109   TypeSourceInfo *TInfo = FD->getTypeSourceInfo();
4110   StorageClass SC = FD->getStorageClass();
4111   DeclarationName Name = FD->getNameInfo().getName();
4112 
4113   FunctionDecl *NewDecl =
4114       FunctionDecl::Create(FD->getASTContext(), DeclCtx, FD->getBeginLoc(),
4115                            FD->getEndLoc(), Name, TInfo->getType(), TInfo, SC);
4116 
4117   NewDecl->setIsMultiVersion();
4118   NewDecl->addAttr(TargetVersionAttr::CreateImplicit(
4119       NewDecl->getASTContext(), "default", NewDecl->getSourceRange()));
4120 
4121   return NewDecl;
4122 }
4123 
4124 void CodeGenModule::emitMultiVersionFunctions() {
4125   std::vector<GlobalDecl> MVFuncsToEmit;
4126   MultiVersionFuncs.swap(MVFuncsToEmit);
4127   for (GlobalDecl GD : MVFuncsToEmit) {
4128     const auto *FD = cast<FunctionDecl>(GD.getDecl());
4129     assert(FD && "Expected a FunctionDecl");
4130 
4131     auto createFunction = [&](const FunctionDecl *Decl, unsigned MVIdx = 0) {
4132       GlobalDecl CurGD{Decl->isDefined() ? Decl->getDefinition() : Decl, MVIdx};
4133       StringRef MangledName = getMangledName(CurGD);
4134       llvm::Constant *Func = GetGlobalValue(MangledName);
4135       if (!Func) {
4136         if (Decl->isDefined()) {
4137           EmitGlobalFunctionDefinition(CurGD, nullptr);
4138           Func = GetGlobalValue(MangledName);
4139         } else {
4140           const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(CurGD);
4141           llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
4142           Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
4143                                    /*DontDefer=*/false, ForDefinition);
4144         }
4145         assert(Func && "This should have just been created");
4146       }
4147       return cast<llvm::Function>(Func);
4148     };
4149 
4150     bool HasDefaultDecl = !FD->isTargetVersionMultiVersion();
4151     bool ShouldEmitResolver =
4152         !getContext().getTargetInfo().getTriple().isAArch64();
4153     SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
4154 
4155     getContext().forEachMultiversionedFunctionVersion(
4156         FD, [&](const FunctionDecl *CurFD) {
4157           llvm::SmallVector<StringRef, 8> Feats;
4158 
4159           if (const auto *TA = CurFD->getAttr<TargetAttr>()) {
4160             TA->getAddedFeatures(Feats);
4161             llvm::Function *Func = createFunction(CurFD);
4162             Options.emplace_back(Func, TA->getArchitecture(), Feats);
4163           } else if (const auto *TVA = CurFD->getAttr<TargetVersionAttr>()) {
4164             bool HasDefaultDef = TVA->isDefaultVersion() &&
4165                                  CurFD->doesThisDeclarationHaveABody();
4166             HasDefaultDecl |= TVA->isDefaultVersion();
4167             ShouldEmitResolver |= (CurFD->isUsed() || HasDefaultDef);
4168             TVA->getFeatures(Feats);
4169             llvm::Function *Func = createFunction(CurFD);
4170             Options.emplace_back(Func, /*Architecture*/ "", Feats);
4171           } else if (const auto *TC = CurFD->getAttr<TargetClonesAttr>()) {
4172             ShouldEmitResolver |= CurFD->doesThisDeclarationHaveABody();
4173             for (unsigned I = 0; I < TC->featuresStrs_size(); ++I) {
4174               if (!TC->isFirstOfVersion(I))
4175                 continue;
4176 
4177               llvm::Function *Func = createFunction(CurFD, I);
4178               StringRef Architecture;
4179               Feats.clear();
4180               if (getTarget().getTriple().isAArch64())
4181                 TC->getFeatures(Feats, I);
4182               else {
4183                 StringRef Version = TC->getFeatureStr(I);
4184                 if (Version.starts_with("arch="))
4185                   Architecture = Version.drop_front(sizeof("arch=") - 1);
4186                 else if (Version != "default")
4187                   Feats.push_back(Version);
4188               }
4189               Options.emplace_back(Func, Architecture, Feats);
4190             }
4191           } else
4192             llvm_unreachable("unexpected MultiVersionKind");
4193         });
4194 
4195     if (!ShouldEmitResolver)
4196       continue;
4197 
4198     if (!HasDefaultDecl) {
4199       FunctionDecl *NewFD = createDefaultTargetVersionFrom(FD);
4200       llvm::Function *Func = createFunction(NewFD);
4201       llvm::SmallVector<StringRef, 1> Feats;
4202       Options.emplace_back(Func, /*Architecture*/ "", Feats);
4203     }
4204 
4205     llvm::Constant *ResolverConstant = GetOrCreateMultiVersionResolver(GD);
4206     if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(ResolverConstant)) {
4207       ResolverConstant = IFunc->getResolver();
4208       if (FD->isTargetClonesMultiVersion() ||
4209           FD->isTargetVersionMultiVersion()) {
4210         std::string MangledName = getMangledNameImpl(
4211             *this, GD, FD, /*OmitMultiVersionMangling=*/true);
4212         if (!GetGlobalValue(MangledName + ".ifunc")) {
4213           const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4214           llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
4215           // In prior versions of Clang, the mangling for ifuncs incorrectly
4216           // included an .ifunc suffix. This alias is generated for backward
4217           // compatibility. It is deprecated, and may be removed in the future.
4218           auto *Alias = llvm::GlobalAlias::create(
4219               DeclTy, 0, getMultiversionLinkage(*this, GD),
4220               MangledName + ".ifunc", IFunc, &getModule());
4221           SetCommonAttributes(FD, Alias);
4222         }
4223       }
4224     }
4225     llvm::Function *ResolverFunc = cast<llvm::Function>(ResolverConstant);
4226 
4227     ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
4228 
4229     if (!ResolverFunc->hasLocalLinkage() && supportsCOMDAT())
4230       ResolverFunc->setComdat(
4231           getModule().getOrInsertComdat(ResolverFunc->getName()));
4232 
4233     const TargetInfo &TI = getTarget();
4234     llvm::stable_sort(
4235         Options, [&TI](const CodeGenFunction::MultiVersionResolverOption &LHS,
4236                        const CodeGenFunction::MultiVersionResolverOption &RHS) {
4237           return TargetMVPriority(TI, LHS) > TargetMVPriority(TI, RHS);
4238         });
4239     CodeGenFunction CGF(*this);
4240     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
4241   }
4242 
4243   // Ensure that any additions to the deferred decls list caused by emitting a
4244   // variant are emitted.  This can happen when the variant itself is inline and
4245   // calls a function without linkage.
4246   if (!MVFuncsToEmit.empty())
4247     EmitDeferred();
4248 
4249   // Ensure that any additions to the multiversion funcs list from either the
4250   // deferred decls or the multiversion functions themselves are emitted.
4251   if (!MultiVersionFuncs.empty())
4252     emitMultiVersionFunctions();
4253 }
4254 
4255 void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
4256   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4257   assert(FD && "Not a FunctionDecl?");
4258   assert(FD->isCPUDispatchMultiVersion() && "Not a multiversion function?");
4259   const auto *DD = FD->getAttr<CPUDispatchAttr>();
4260   assert(DD && "Not a cpu_dispatch Function?");
4261 
4262   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4263   llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
4264 
4265   StringRef ResolverName = getMangledName(GD);
4266   UpdateMultiVersionNames(GD, FD, ResolverName);
4267 
4268   llvm::Type *ResolverType;
4269   GlobalDecl ResolverGD;
4270   if (getTarget().supportsIFunc()) {
4271     ResolverType = llvm::FunctionType::get(
4272         llvm::PointerType::get(DeclTy,
4273                                getTypes().getTargetAddressSpace(FD->getType())),
4274         false);
4275   }
4276   else {
4277     ResolverType = DeclTy;
4278     ResolverGD = GD;
4279   }
4280 
4281   auto *ResolverFunc = cast<llvm::Function>(GetOrCreateLLVMFunction(
4282       ResolverName, ResolverType, ResolverGD, /*ForVTable=*/false));
4283   ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
4284   if (supportsCOMDAT())
4285     ResolverFunc->setComdat(
4286         getModule().getOrInsertComdat(ResolverFunc->getName()));
4287 
4288   SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
4289   const TargetInfo &Target = getTarget();
4290   unsigned Index = 0;
4291   for (const IdentifierInfo *II : DD->cpus()) {
4292     // Get the name of the target function so we can look it up/create it.
4293     std::string MangledName = getMangledNameImpl(*this, GD, FD, true) +
4294                               getCPUSpecificMangling(*this, II->getName());
4295 
4296     llvm::Constant *Func = GetGlobalValue(MangledName);
4297 
4298     if (!Func) {
4299       GlobalDecl ExistingDecl = Manglings.lookup(MangledName);
4300       if (ExistingDecl.getDecl() &&
4301           ExistingDecl.getDecl()->getAsFunction()->isDefined()) {
4302         EmitGlobalFunctionDefinition(ExistingDecl, nullptr);
4303         Func = GetGlobalValue(MangledName);
4304       } else {
4305         if (!ExistingDecl.getDecl())
4306           ExistingDecl = GD.getWithMultiVersionIndex(Index);
4307 
4308       Func = GetOrCreateLLVMFunction(
4309           MangledName, DeclTy, ExistingDecl,
4310           /*ForVTable=*/false, /*DontDefer=*/true,
4311           /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
4312       }
4313     }
4314 
4315     llvm::SmallVector<StringRef, 32> Features;
4316     Target.getCPUSpecificCPUDispatchFeatures(II->getName(), Features);
4317     llvm::transform(Features, Features.begin(),
4318                     [](StringRef Str) { return Str.substr(1); });
4319     llvm::erase_if(Features, [&Target](StringRef Feat) {
4320       return !Target.validateCpuSupports(Feat);
4321     });
4322     Options.emplace_back(cast<llvm::Function>(Func), StringRef{}, Features);
4323     ++Index;
4324   }
4325 
4326   llvm::stable_sort(
4327       Options, [](const CodeGenFunction::MultiVersionResolverOption &LHS,
4328                   const CodeGenFunction::MultiVersionResolverOption &RHS) {
4329         return llvm::X86::getCpuSupportsMask(LHS.Conditions.Features) >
4330                llvm::X86::getCpuSupportsMask(RHS.Conditions.Features);
4331       });
4332 
4333   // If the list contains multiple 'default' versions, such as when it contains
4334   // 'pentium' and 'generic', don't emit the call to the generic one (since we
4335   // always run on at least a 'pentium'). We do this by deleting the 'least
4336   // advanced' (read, lowest mangling letter).
4337   while (Options.size() > 1 &&
4338          llvm::all_of(llvm::X86::getCpuSupportsMask(
4339                           (Options.end() - 2)->Conditions.Features),
4340                       [](auto X) { return X == 0; })) {
4341     StringRef LHSName = (Options.end() - 2)->Function->getName();
4342     StringRef RHSName = (Options.end() - 1)->Function->getName();
4343     if (LHSName.compare(RHSName) < 0)
4344       Options.erase(Options.end() - 2);
4345     else
4346       Options.erase(Options.end() - 1);
4347   }
4348 
4349   CodeGenFunction CGF(*this);
4350   CGF.EmitMultiVersionResolver(ResolverFunc, Options);
4351 
4352   if (getTarget().supportsIFunc()) {
4353     llvm::GlobalValue::LinkageTypes Linkage = getMultiversionLinkage(*this, GD);
4354     auto *IFunc = cast<llvm::GlobalValue>(GetOrCreateMultiVersionResolver(GD));
4355 
4356     // Fix up function declarations that were created for cpu_specific before
4357     // cpu_dispatch was known
4358     if (!isa<llvm::GlobalIFunc>(IFunc)) {
4359       assert(cast<llvm::Function>(IFunc)->isDeclaration());
4360       auto *GI = llvm::GlobalIFunc::create(DeclTy, 0, Linkage, "", ResolverFunc,
4361                                            &getModule());
4362       GI->takeName(IFunc);
4363       IFunc->replaceAllUsesWith(GI);
4364       IFunc->eraseFromParent();
4365       IFunc = GI;
4366     }
4367 
4368     std::string AliasName = getMangledNameImpl(
4369         *this, GD, FD, /*OmitMultiVersionMangling=*/true);
4370     llvm::Constant *AliasFunc = GetGlobalValue(AliasName);
4371     if (!AliasFunc) {
4372       auto *GA = llvm::GlobalAlias::create(DeclTy, 0, Linkage, AliasName, IFunc,
4373                                            &getModule());
4374       SetCommonAttributes(GD, GA);
4375     }
4376   }
4377 }
4378 
4379 /// Adds a declaration to the list of multi version functions if not present.
4380 void CodeGenModule::AddDeferredMultiVersionResolverToEmit(GlobalDecl GD) {
4381   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4382   assert(FD && "Not a FunctionDecl?");
4383 
4384   if (FD->isTargetVersionMultiVersion() || FD->isTargetClonesMultiVersion()) {
4385     std::string MangledName =
4386         getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
4387     if (!DeferredResolversToEmit.insert(MangledName).second)
4388       return;
4389   }
4390   MultiVersionFuncs.push_back(GD);
4391 }
4392 
4393 /// If a dispatcher for the specified mangled name is not in the module, create
4394 /// and return an llvm Function with the specified type.
4395 llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(GlobalDecl GD) {
4396   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4397   assert(FD && "Not a FunctionDecl?");
4398 
4399   std::string MangledName =
4400       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
4401 
4402   // Holds the name of the resolver, in ifunc mode this is the ifunc (which has
4403   // a separate resolver).
4404   std::string ResolverName = MangledName;
4405   if (getTarget().supportsIFunc()) {
4406     switch (FD->getMultiVersionKind()) {
4407     case MultiVersionKind::None:
4408       llvm_unreachable("unexpected MultiVersionKind::None for resolver");
4409     case MultiVersionKind::Target:
4410     case MultiVersionKind::CPUSpecific:
4411     case MultiVersionKind::CPUDispatch:
4412       ResolverName += ".ifunc";
4413       break;
4414     case MultiVersionKind::TargetClones:
4415     case MultiVersionKind::TargetVersion:
4416       break;
4417     }
4418   } else if (FD->isTargetMultiVersion()) {
4419     ResolverName += ".resolver";
4420   }
4421 
4422   // If the resolver has already been created, just return it.
4423   if (llvm::GlobalValue *ResolverGV = GetGlobalValue(ResolverName))
4424     return ResolverGV;
4425 
4426   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4427   llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
4428 
4429   // The resolver needs to be created. For target and target_clones, defer
4430   // creation until the end of the TU.
4431   if (FD->isTargetMultiVersion() || FD->isTargetClonesMultiVersion())
4432     AddDeferredMultiVersionResolverToEmit(GD);
4433 
4434   // For cpu_specific, don't create an ifunc yet because we don't know if the
4435   // cpu_dispatch will be emitted in this translation unit.
4436   if (getTarget().supportsIFunc() && !FD->isCPUSpecificMultiVersion()) {
4437     llvm::Type *ResolverType = llvm::FunctionType::get(
4438         llvm::PointerType::get(DeclTy,
4439                                getTypes().getTargetAddressSpace(FD->getType())),
4440         false);
4441     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
4442         MangledName + ".resolver", ResolverType, GlobalDecl{},
4443         /*ForVTable=*/false);
4444     llvm::GlobalIFunc *GIF =
4445         llvm::GlobalIFunc::create(DeclTy, 0, getMultiversionLinkage(*this, GD),
4446                                   "", Resolver, &getModule());
4447     GIF->setName(ResolverName);
4448     SetCommonAttributes(FD, GIF);
4449 
4450     return GIF;
4451   }
4452 
4453   llvm::Constant *Resolver = GetOrCreateLLVMFunction(
4454       ResolverName, DeclTy, GlobalDecl{}, /*ForVTable=*/false);
4455   assert(isa<llvm::GlobalValue>(Resolver) &&
4456          "Resolver should be created for the first time");
4457   SetCommonAttributes(FD, cast<llvm::GlobalValue>(Resolver));
4458   return Resolver;
4459 }
4460 
4461 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the
4462 /// module, create and return an llvm Function with the specified type. If there
4463 /// is something in the module with the specified name, return it potentially
4464 /// bitcasted to the right type.
4465 ///
4466 /// If D is non-null, it specifies a decl that correspond to this.  This is used
4467 /// to set the attributes on the function when it is first created.
4468 llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
4469     StringRef MangledName, llvm::Type *Ty, GlobalDecl GD, bool ForVTable,
4470     bool DontDefer, bool IsThunk, llvm::AttributeList ExtraAttrs,
4471     ForDefinition_t IsForDefinition) {
4472   const Decl *D = GD.getDecl();
4473 
4474   // Any attempts to use a MultiVersion function should result in retrieving
4475   // the iFunc instead. Name Mangling will handle the rest of the changes.
4476   if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D)) {
4477     // For the device mark the function as one that should be emitted.
4478     if (getLangOpts().OpenMPIsTargetDevice && OpenMPRuntime &&
4479         !OpenMPRuntime->markAsGlobalTarget(GD) && FD->isDefined() &&
4480         !DontDefer && !IsForDefinition) {
4481       if (const FunctionDecl *FDDef = FD->getDefinition()) {
4482         GlobalDecl GDDef;
4483         if (const auto *CD = dyn_cast<CXXConstructorDecl>(FDDef))
4484           GDDef = GlobalDecl(CD, GD.getCtorType());
4485         else if (const auto *DD = dyn_cast<CXXDestructorDecl>(FDDef))
4486           GDDef = GlobalDecl(DD, GD.getDtorType());
4487         else
4488           GDDef = GlobalDecl(FDDef);
4489         EmitGlobal(GDDef);
4490       }
4491     }
4492 
4493     if (FD->isMultiVersion()) {
4494       UpdateMultiVersionNames(GD, FD, MangledName);
4495       if (FD->getASTContext().getTargetInfo().getTriple().isAArch64() &&
4496           !FD->isUsed())
4497         AddDeferredMultiVersionResolverToEmit(GD);
4498       else if (!IsForDefinition)
4499         return GetOrCreateMultiVersionResolver(GD);
4500     }
4501   }
4502 
4503   // Lookup the entry, lazily creating it if necessary.
4504   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4505   if (Entry) {
4506     if (WeakRefReferences.erase(Entry)) {
4507       const FunctionDecl *FD = cast_or_null<FunctionDecl>(D);
4508       if (FD && !FD->hasAttr<WeakAttr>())
4509         Entry->setLinkage(llvm::Function::ExternalLinkage);
4510     }
4511 
4512     // Handle dropped DLL attributes.
4513     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
4514         !shouldMapVisibilityToDLLExport(cast_or_null<NamedDecl>(D))) {
4515       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
4516       setDSOLocal(Entry);
4517     }
4518 
4519     // If there are two attempts to define the same mangled name, issue an
4520     // error.
4521     if (IsForDefinition && !Entry->isDeclaration()) {
4522       GlobalDecl OtherGD;
4523       // Check that GD is not yet in DiagnosedConflictingDefinitions is required
4524       // to make sure that we issue an error only once.
4525       if (lookupRepresentativeDecl(MangledName, OtherGD) &&
4526           (GD.getCanonicalDecl().getDecl() !=
4527            OtherGD.getCanonicalDecl().getDecl()) &&
4528           DiagnosedConflictingDefinitions.insert(GD).second) {
4529         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
4530             << MangledName;
4531         getDiags().Report(OtherGD.getDecl()->getLocation(),
4532                           diag::note_previous_definition);
4533       }
4534     }
4535 
4536     if ((isa<llvm::Function>(Entry) || isa<llvm::GlobalAlias>(Entry)) &&
4537         (Entry->getValueType() == Ty)) {
4538       return Entry;
4539     }
4540 
4541     // Make sure the result is of the correct type.
4542     // (If function is requested for a definition, we always need to create a new
4543     // function, not just return a bitcast.)
4544     if (!IsForDefinition)
4545       return Entry;
4546   }
4547 
4548   // This function doesn't have a complete type (for example, the return
4549   // type is an incomplete struct). Use a fake type instead, and make
4550   // sure not to try to set attributes.
4551   bool IsIncompleteFunction = false;
4552 
4553   llvm::FunctionType *FTy;
4554   if (isa<llvm::FunctionType>(Ty)) {
4555     FTy = cast<llvm::FunctionType>(Ty);
4556   } else {
4557     FTy = llvm::FunctionType::get(VoidTy, false);
4558     IsIncompleteFunction = true;
4559   }
4560 
4561   llvm::Function *F =
4562       llvm::Function::Create(FTy, llvm::Function::ExternalLinkage,
4563                              Entry ? StringRef() : MangledName, &getModule());
4564 
4565   // Store the declaration associated with this function so it is potentially
4566   // updated by further declarations or definitions and emitted at the end.
4567   if (D && D->hasAttr<AnnotateAttr>())
4568     DeferredAnnotations[MangledName] = cast<ValueDecl>(D);
4569 
4570   // If we already created a function with the same mangled name (but different
4571   // type) before, take its name and add it to the list of functions to be
4572   // replaced with F at the end of CodeGen.
4573   //
4574   // This happens if there is a prototype for a function (e.g. "int f()") and
4575   // then a definition of a different type (e.g. "int f(int x)").
4576   if (Entry) {
4577     F->takeName(Entry);
4578 
4579     // This might be an implementation of a function without a prototype, in
4580     // which case, try to do special replacement of calls which match the new
4581     // prototype.  The really key thing here is that we also potentially drop
4582     // arguments from the call site so as to make a direct call, which makes the
4583     // inliner happier and suppresses a number of optimizer warnings (!) about
4584     // dropping arguments.
4585     if (!Entry->use_empty()) {
4586       ReplaceUsesOfNonProtoTypeWithRealFunction(Entry, F);
4587       Entry->removeDeadConstantUsers();
4588     }
4589 
4590     addGlobalValReplacement(Entry, F);
4591   }
4592 
4593   assert(F->getName() == MangledName && "name was uniqued!");
4594   if (D)
4595     SetFunctionAttributes(GD, F, IsIncompleteFunction, IsThunk);
4596   if (ExtraAttrs.hasFnAttrs()) {
4597     llvm::AttrBuilder B(F->getContext(), ExtraAttrs.getFnAttrs());
4598     F->addFnAttrs(B);
4599   }
4600 
4601   if (!DontDefer) {
4602     // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
4603     // each other bottoming out with the base dtor.  Therefore we emit non-base
4604     // dtors on usage, even if there is no dtor definition in the TU.
4605     if (isa_and_nonnull<CXXDestructorDecl>(D) &&
4606         getCXXABI().useThunkForDtorVariant(cast<CXXDestructorDecl>(D),
4607                                            GD.getDtorType()))
4608       addDeferredDeclToEmit(GD);
4609 
4610     // This is the first use or definition of a mangled name.  If there is a
4611     // deferred decl with this name, remember that we need to emit it at the end
4612     // of the file.
4613     auto DDI = DeferredDecls.find(MangledName);
4614     if (DDI != DeferredDecls.end()) {
4615       // Move the potentially referenced deferred decl to the
4616       // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
4617       // don't need it anymore).
4618       addDeferredDeclToEmit(DDI->second);
4619       DeferredDecls.erase(DDI);
4620 
4621       // Otherwise, there are cases we have to worry about where we're
4622       // using a declaration for which we must emit a definition but where
4623       // we might not find a top-level definition:
4624       //   - member functions defined inline in their classes
4625       //   - friend functions defined inline in some class
4626       //   - special member functions with implicit definitions
4627       // If we ever change our AST traversal to walk into class methods,
4628       // this will be unnecessary.
4629       //
4630       // We also don't emit a definition for a function if it's going to be an
4631       // entry in a vtable, unless it's already marked as used.
4632     } else if (getLangOpts().CPlusPlus && D) {
4633       // Look for a declaration that's lexically in a record.
4634       for (const auto *FD = cast<FunctionDecl>(D)->getMostRecentDecl(); FD;
4635            FD = FD->getPreviousDecl()) {
4636         if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
4637           if (FD->doesThisDeclarationHaveABody()) {
4638             addDeferredDeclToEmit(GD.getWithDecl(FD));
4639             break;
4640           }
4641         }
4642       }
4643     }
4644   }
4645 
4646   // Make sure the result is of the requested type.
4647   if (!IsIncompleteFunction) {
4648     assert(F->getFunctionType() == Ty);
4649     return F;
4650   }
4651 
4652   return F;
4653 }
4654 
4655 /// GetAddrOfFunction - Return the address of the given function.  If Ty is
4656 /// non-null, then this function will use the specified type if it has to
4657 /// create it (this occurs when we see a definition of the function).
4658 llvm::Constant *
4659 CodeGenModule::GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty, bool ForVTable,
4660                                  bool DontDefer,
4661                                  ForDefinition_t IsForDefinition) {
4662   // If there was no specific requested type, just convert it now.
4663   if (!Ty) {
4664     const auto *FD = cast<FunctionDecl>(GD.getDecl());
4665     Ty = getTypes().ConvertType(FD->getType());
4666   }
4667 
4668   // Devirtualized destructor calls may come through here instead of via
4669   // getAddrOfCXXStructor. Make sure we use the MS ABI base destructor instead
4670   // of the complete destructor when necessary.
4671   if (const auto *DD = dyn_cast<CXXDestructorDecl>(GD.getDecl())) {
4672     if (getTarget().getCXXABI().isMicrosoft() &&
4673         GD.getDtorType() == Dtor_Complete &&
4674         DD->getParent()->getNumVBases() == 0)
4675       GD = GlobalDecl(DD, Dtor_Base);
4676   }
4677 
4678   StringRef MangledName = getMangledName(GD);
4679   auto *F = GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
4680                                     /*IsThunk=*/false, llvm::AttributeList(),
4681                                     IsForDefinition);
4682   // Returns kernel handle for HIP kernel stub function.
4683   if (LangOpts.CUDA && !LangOpts.CUDAIsDevice &&
4684       cast<FunctionDecl>(GD.getDecl())->hasAttr<CUDAGlobalAttr>()) {
4685     auto *Handle = getCUDARuntime().getKernelHandle(
4686         cast<llvm::Function>(F->stripPointerCasts()), GD);
4687     if (IsForDefinition)
4688       return F;
4689     return Handle;
4690   }
4691   return F;
4692 }
4693 
4694 llvm::Constant *CodeGenModule::GetFunctionStart(const ValueDecl *Decl) {
4695   llvm::GlobalValue *F =
4696       cast<llvm::GlobalValue>(GetAddrOfFunction(Decl)->stripPointerCasts());
4697 
4698   return llvm::NoCFIValue::get(F);
4699 }
4700 
4701 static const FunctionDecl *
4702 GetRuntimeFunctionDecl(ASTContext &C, StringRef Name) {
4703   TranslationUnitDecl *TUDecl = C.getTranslationUnitDecl();
4704   DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
4705 
4706   IdentifierInfo &CII = C.Idents.get(Name);
4707   for (const auto *Result : DC->lookup(&CII))
4708     if (const auto *FD = dyn_cast<FunctionDecl>(Result))
4709       return FD;
4710 
4711   if (!C.getLangOpts().CPlusPlus)
4712     return nullptr;
4713 
4714   // Demangle the premangled name from getTerminateFn()
4715   IdentifierInfo &CXXII =
4716       (Name == "_ZSt9terminatev" || Name == "?terminate@@YAXXZ")
4717           ? C.Idents.get("terminate")
4718           : C.Idents.get(Name);
4719 
4720   for (const auto &N : {"__cxxabiv1", "std"}) {
4721     IdentifierInfo &NS = C.Idents.get(N);
4722     for (const auto *Result : DC->lookup(&NS)) {
4723       const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(Result);
4724       if (auto *LSD = dyn_cast<LinkageSpecDecl>(Result))
4725         for (const auto *Result : LSD->lookup(&NS))
4726           if ((ND = dyn_cast<NamespaceDecl>(Result)))
4727             break;
4728 
4729       if (ND)
4730         for (const auto *Result : ND->lookup(&CXXII))
4731           if (const auto *FD = dyn_cast<FunctionDecl>(Result))
4732             return FD;
4733     }
4734   }
4735 
4736   return nullptr;
4737 }
4738 
4739 /// CreateRuntimeFunction - Create a new runtime function with the specified
4740 /// type and name.
4741 llvm::FunctionCallee
4742 CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
4743                                      llvm::AttributeList ExtraAttrs, bool Local,
4744                                      bool AssumeConvergent) {
4745   if (AssumeConvergent) {
4746     ExtraAttrs =
4747         ExtraAttrs.addFnAttribute(VMContext, llvm::Attribute::Convergent);
4748   }
4749 
4750   llvm::Constant *C =
4751       GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(), /*ForVTable=*/false,
4752                               /*DontDefer=*/false, /*IsThunk=*/false,
4753                               ExtraAttrs);
4754 
4755   if (auto *F = dyn_cast<llvm::Function>(C)) {
4756     if (F->empty()) {
4757       F->setCallingConv(getRuntimeCC());
4758 
4759       // In Windows Itanium environments, try to mark runtime functions
4760       // dllimport. For Mingw and MSVC, don't. We don't really know if the user
4761       // will link their standard library statically or dynamically. Marking
4762       // functions imported when they are not imported can cause linker errors
4763       // and warnings.
4764       if (!Local && getTriple().isWindowsItaniumEnvironment() &&
4765           !getCodeGenOpts().LTOVisibilityPublicStd) {
4766         const FunctionDecl *FD = GetRuntimeFunctionDecl(Context, Name);
4767         if (!FD || FD->hasAttr<DLLImportAttr>()) {
4768           F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
4769           F->setLinkage(llvm::GlobalValue::ExternalLinkage);
4770         }
4771       }
4772       setDSOLocal(F);
4773     }
4774   }
4775 
4776   return {FTy, C};
4777 }
4778 
4779 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
4780 /// create and return an llvm GlobalVariable with the specified type and address
4781 /// space. If there is something in the module with the specified name, return
4782 /// it potentially bitcasted to the right type.
4783 ///
4784 /// If D is non-null, it specifies a decl that correspond to this.  This is used
4785 /// to set the attributes on the global when it is first created.
4786 ///
4787 /// If IsForDefinition is true, it is guaranteed that an actual global with
4788 /// type Ty will be returned, not conversion of a variable with the same
4789 /// mangled name but some other type.
4790 llvm::Constant *
4791 CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, llvm::Type *Ty,
4792                                      LangAS AddrSpace, const VarDecl *D,
4793                                      ForDefinition_t IsForDefinition) {
4794   // Lookup the entry, lazily creating it if necessary.
4795   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4796   unsigned TargetAS = getContext().getTargetAddressSpace(AddrSpace);
4797   if (Entry) {
4798     if (WeakRefReferences.erase(Entry)) {
4799       if (D && !D->hasAttr<WeakAttr>())
4800         Entry->setLinkage(llvm::Function::ExternalLinkage);
4801     }
4802 
4803     // Handle dropped DLL attributes.
4804     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
4805         !shouldMapVisibilityToDLLExport(D))
4806       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
4807 
4808     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd && D)
4809       getOpenMPRuntime().registerTargetGlobalVariable(D, Entry);
4810 
4811     if (Entry->getValueType() == Ty && Entry->getAddressSpace() == TargetAS)
4812       return Entry;
4813 
4814     // If there are two attempts to define the same mangled name, issue an
4815     // error.
4816     if (IsForDefinition && !Entry->isDeclaration()) {
4817       GlobalDecl OtherGD;
4818       const VarDecl *OtherD;
4819 
4820       // Check that D is not yet in DiagnosedConflictingDefinitions is required
4821       // to make sure that we issue an error only once.
4822       if (D && lookupRepresentativeDecl(MangledName, OtherGD) &&
4823           (D->getCanonicalDecl() != OtherGD.getCanonicalDecl().getDecl()) &&
4824           (OtherD = dyn_cast<VarDecl>(OtherGD.getDecl())) &&
4825           OtherD->hasInit() &&
4826           DiagnosedConflictingDefinitions.insert(D).second) {
4827         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
4828             << MangledName;
4829         getDiags().Report(OtherGD.getDecl()->getLocation(),
4830                           diag::note_previous_definition);
4831       }
4832     }
4833 
4834     // Make sure the result is of the correct type.
4835     if (Entry->getType()->getAddressSpace() != TargetAS)
4836       return llvm::ConstantExpr::getAddrSpaceCast(
4837           Entry, llvm::PointerType::get(Ty->getContext(), TargetAS));
4838 
4839     // (If global is requested for a definition, we always need to create a new
4840     // global, not just return a bitcast.)
4841     if (!IsForDefinition)
4842       return Entry;
4843   }
4844 
4845   auto DAddrSpace = GetGlobalVarAddressSpace(D);
4846 
4847   auto *GV = new llvm::GlobalVariable(
4848       getModule(), Ty, false, llvm::GlobalValue::ExternalLinkage, nullptr,
4849       MangledName, nullptr, llvm::GlobalVariable::NotThreadLocal,
4850       getContext().getTargetAddressSpace(DAddrSpace));
4851 
4852   // If we already created a global with the same mangled name (but different
4853   // type) before, take its name and remove it from its parent.
4854   if (Entry) {
4855     GV->takeName(Entry);
4856 
4857     if (!Entry->use_empty()) {
4858       Entry->replaceAllUsesWith(GV);
4859     }
4860 
4861     Entry->eraseFromParent();
4862   }
4863 
4864   // This is the first use or definition of a mangled name.  If there is a
4865   // deferred decl with this name, remember that we need to emit it at the end
4866   // of the file.
4867   auto DDI = DeferredDecls.find(MangledName);
4868   if (DDI != DeferredDecls.end()) {
4869     // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
4870     // list, and remove it from DeferredDecls (since we don't need it anymore).
4871     addDeferredDeclToEmit(DDI->second);
4872     DeferredDecls.erase(DDI);
4873   }
4874 
4875   // Handle things which are present even on external declarations.
4876   if (D) {
4877     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd)
4878       getOpenMPRuntime().registerTargetGlobalVariable(D, GV);
4879 
4880     // FIXME: This code is overly simple and should be merged with other global
4881     // handling.
4882     GV->setConstant(D->getType().isConstantStorage(getContext(), false, false));
4883 
4884     GV->setAlignment(getContext().getDeclAlign(D).getAsAlign());
4885 
4886     setLinkageForGV(GV, D);
4887 
4888     if (D->getTLSKind()) {
4889       if (D->getTLSKind() == VarDecl::TLS_Dynamic)
4890         CXXThreadLocals.push_back(D);
4891       setTLSMode(GV, *D);
4892     }
4893 
4894     setGVProperties(GV, D);
4895 
4896     // If required by the ABI, treat declarations of static data members with
4897     // inline initializers as definitions.
4898     if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
4899       EmitGlobalVarDefinition(D);
4900     }
4901 
4902     // Emit section information for extern variables.
4903     if (D->hasExternalStorage()) {
4904       if (const SectionAttr *SA = D->getAttr<SectionAttr>())
4905         GV->setSection(SA->getName());
4906     }
4907 
4908     // Handle XCore specific ABI requirements.
4909     if (getTriple().getArch() == llvm::Triple::xcore &&
4910         D->getLanguageLinkage() == CLanguageLinkage &&
4911         D->getType().isConstant(Context) &&
4912         isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
4913       GV->setSection(".cp.rodata");
4914 
4915     // Handle code model attribute
4916     if (const auto *CMA = D->getAttr<CodeModelAttr>())
4917       GV->setCodeModel(CMA->getModel());
4918 
4919     // Check if we a have a const declaration with an initializer, we may be
4920     // able to emit it as available_externally to expose it's value to the
4921     // optimizer.
4922     if (Context.getLangOpts().CPlusPlus && GV->hasExternalLinkage() &&
4923         D->getType().isConstQualified() && !GV->hasInitializer() &&
4924         !D->hasDefinition() && D->hasInit() && !D->hasAttr<DLLImportAttr>()) {
4925       const auto *Record =
4926           Context.getBaseElementType(D->getType())->getAsCXXRecordDecl();
4927       bool HasMutableFields = Record && Record->hasMutableFields();
4928       if (!HasMutableFields) {
4929         const VarDecl *InitDecl;
4930         const Expr *InitExpr = D->getAnyInitializer(InitDecl);
4931         if (InitExpr) {
4932           ConstantEmitter emitter(*this);
4933           llvm::Constant *Init = emitter.tryEmitForInitializer(*InitDecl);
4934           if (Init) {
4935             auto *InitType = Init->getType();
4936             if (GV->getValueType() != InitType) {
4937               // The type of the initializer does not match the definition.
4938               // This happens when an initializer has a different type from
4939               // the type of the global (because of padding at the end of a
4940               // structure for instance).
4941               GV->setName(StringRef());
4942               // Make a new global with the correct type, this is now guaranteed
4943               // to work.
4944               auto *NewGV = cast<llvm::GlobalVariable>(
4945                   GetAddrOfGlobalVar(D, InitType, IsForDefinition)
4946                       ->stripPointerCasts());
4947 
4948               // Erase the old global, since it is no longer used.
4949               GV->eraseFromParent();
4950               GV = NewGV;
4951             } else {
4952               GV->setInitializer(Init);
4953               GV->setConstant(true);
4954               GV->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
4955             }
4956             emitter.finalize(GV);
4957           }
4958         }
4959       }
4960     }
4961   }
4962 
4963   if (D &&
4964       D->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly) {
4965     getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
4966     // External HIP managed variables needed to be recorded for transformation
4967     // in both device and host compilations.
4968     if (getLangOpts().CUDA && D && D->hasAttr<HIPManagedAttr>() &&
4969         D->hasExternalStorage())
4970       getCUDARuntime().handleVarRegistration(D, *GV);
4971   }
4972 
4973   if (D)
4974     SanitizerMD->reportGlobal(GV, *D);
4975 
4976   LangAS ExpectedAS =
4977       D ? D->getType().getAddressSpace()
4978         : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
4979   assert(getContext().getTargetAddressSpace(ExpectedAS) == TargetAS);
4980   if (DAddrSpace != ExpectedAS) {
4981     return getTargetCodeGenInfo().performAddrSpaceCast(
4982         *this, GV, DAddrSpace, ExpectedAS,
4983         llvm::PointerType::get(getLLVMContext(), TargetAS));
4984   }
4985 
4986   return GV;
4987 }
4988 
4989 llvm::Constant *
4990 CodeGenModule::GetAddrOfGlobal(GlobalDecl GD, ForDefinition_t IsForDefinition) {
4991   const Decl *D = GD.getDecl();
4992 
4993   if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D))
4994     return getAddrOfCXXStructor(GD, /*FnInfo=*/nullptr, /*FnType=*/nullptr,
4995                                 /*DontDefer=*/false, IsForDefinition);
4996 
4997   if (isa<CXXMethodDecl>(D)) {
4998     auto FInfo =
4999         &getTypes().arrangeCXXMethodDeclaration(cast<CXXMethodDecl>(D));
5000     auto Ty = getTypes().GetFunctionType(*FInfo);
5001     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
5002                              IsForDefinition);
5003   }
5004 
5005   if (isa<FunctionDecl>(D)) {
5006     const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
5007     llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
5008     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
5009                              IsForDefinition);
5010   }
5011 
5012   return GetAddrOfGlobalVar(cast<VarDecl>(D), /*Ty=*/nullptr, IsForDefinition);
5013 }
5014 
5015 llvm::GlobalVariable *CodeGenModule::CreateOrReplaceCXXRuntimeVariable(
5016     StringRef Name, llvm::Type *Ty, llvm::GlobalValue::LinkageTypes Linkage,
5017     llvm::Align Alignment) {
5018   llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name);
5019   llvm::GlobalVariable *OldGV = nullptr;
5020 
5021   if (GV) {
5022     // Check if the variable has the right type.
5023     if (GV->getValueType() == Ty)
5024       return GV;
5025 
5026     // Because C++ name mangling, the only way we can end up with an already
5027     // existing global with the same name is if it has been declared extern "C".
5028     assert(GV->isDeclaration() && "Declaration has wrong type!");
5029     OldGV = GV;
5030   }
5031 
5032   // Create a new variable.
5033   GV = new llvm::GlobalVariable(getModule(), Ty, /*isConstant=*/true,
5034                                 Linkage, nullptr, Name);
5035 
5036   if (OldGV) {
5037     // Replace occurrences of the old variable if needed.
5038     GV->takeName(OldGV);
5039 
5040     if (!OldGV->use_empty()) {
5041       OldGV->replaceAllUsesWith(GV);
5042     }
5043 
5044     OldGV->eraseFromParent();
5045   }
5046 
5047   if (supportsCOMDAT() && GV->isWeakForLinker() &&
5048       !GV->hasAvailableExternallyLinkage())
5049     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
5050 
5051   GV->setAlignment(Alignment);
5052 
5053   return GV;
5054 }
5055 
5056 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
5057 /// given global variable.  If Ty is non-null and if the global doesn't exist,
5058 /// then it will be created with the specified type instead of whatever the
5059 /// normal requested type would be. If IsForDefinition is true, it is guaranteed
5060 /// that an actual global with type Ty will be returned, not conversion of a
5061 /// variable with the same mangled name but some other type.
5062 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
5063                                                   llvm::Type *Ty,
5064                                            ForDefinition_t IsForDefinition) {
5065   assert(D->hasGlobalStorage() && "Not a global variable");
5066   QualType ASTTy = D->getType();
5067   if (!Ty)
5068     Ty = getTypes().ConvertTypeForMem(ASTTy);
5069 
5070   StringRef MangledName = getMangledName(D);
5071   return GetOrCreateLLVMGlobal(MangledName, Ty, ASTTy.getAddressSpace(), D,
5072                                IsForDefinition);
5073 }
5074 
5075 /// CreateRuntimeVariable - Create a new runtime global variable with the
5076 /// specified type and name.
5077 llvm::Constant *
5078 CodeGenModule::CreateRuntimeVariable(llvm::Type *Ty,
5079                                      StringRef Name) {
5080   LangAS AddrSpace = getContext().getLangOpts().OpenCL ? LangAS::opencl_global
5081                                                        : LangAS::Default;
5082   auto *Ret = GetOrCreateLLVMGlobal(Name, Ty, AddrSpace, nullptr);
5083   setDSOLocal(cast<llvm::GlobalValue>(Ret->stripPointerCasts()));
5084   return Ret;
5085 }
5086 
5087 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
5088   assert(!D->getInit() && "Cannot emit definite definitions here!");
5089 
5090   StringRef MangledName = getMangledName(D);
5091   llvm::GlobalValue *GV = GetGlobalValue(MangledName);
5092 
5093   // We already have a definition, not declaration, with the same mangled name.
5094   // Emitting of declaration is not required (and actually overwrites emitted
5095   // definition).
5096   if (GV && !GV->isDeclaration())
5097     return;
5098 
5099   // If we have not seen a reference to this variable yet, place it into the
5100   // deferred declarations table to be emitted if needed later.
5101   if (!MustBeEmitted(D) && !GV) {
5102       DeferredDecls[MangledName] = D;
5103       return;
5104   }
5105 
5106   // The tentative definition is the only definition.
5107   EmitGlobalVarDefinition(D);
5108 }
5109 
5110 void CodeGenModule::EmitExternalDeclaration(const VarDecl *D) {
5111   EmitExternalVarDeclaration(D);
5112 }
5113 
5114 CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const {
5115   return Context.toCharUnitsFromBits(
5116       getDataLayout().getTypeStoreSizeInBits(Ty));
5117 }
5118 
5119 LangAS CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
5120   if (LangOpts.OpenCL) {
5121     LangAS AS = D ? D->getType().getAddressSpace() : LangAS::opencl_global;
5122     assert(AS == LangAS::opencl_global ||
5123            AS == LangAS::opencl_global_device ||
5124            AS == LangAS::opencl_global_host ||
5125            AS == LangAS::opencl_constant ||
5126            AS == LangAS::opencl_local ||
5127            AS >= LangAS::FirstTargetAddressSpace);
5128     return AS;
5129   }
5130 
5131   if (LangOpts.SYCLIsDevice &&
5132       (!D || D->getType().getAddressSpace() == LangAS::Default))
5133     return LangAS::sycl_global;
5134 
5135   if (LangOpts.CUDA && LangOpts.CUDAIsDevice) {
5136     if (D) {
5137       if (D->hasAttr<CUDAConstantAttr>())
5138         return LangAS::cuda_constant;
5139       if (D->hasAttr<CUDASharedAttr>())
5140         return LangAS::cuda_shared;
5141       if (D->hasAttr<CUDADeviceAttr>())
5142         return LangAS::cuda_device;
5143       if (D->getType().isConstQualified())
5144         return LangAS::cuda_constant;
5145     }
5146     return LangAS::cuda_device;
5147   }
5148 
5149   if (LangOpts.OpenMP) {
5150     LangAS AS;
5151     if (OpenMPRuntime->hasAllocateAttributeForGlobalVar(D, AS))
5152       return AS;
5153   }
5154   return getTargetCodeGenInfo().getGlobalVarAddressSpace(*this, D);
5155 }
5156 
5157 LangAS CodeGenModule::GetGlobalConstantAddressSpace() const {
5158   // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
5159   if (LangOpts.OpenCL)
5160     return LangAS::opencl_constant;
5161   if (LangOpts.SYCLIsDevice)
5162     return LangAS::sycl_global;
5163   if (LangOpts.HIP && LangOpts.CUDAIsDevice && getTriple().isSPIRV())
5164     // For HIPSPV map literals to cuda_device (maps to CrossWorkGroup in SPIR-V)
5165     // instead of default AS (maps to Generic in SPIR-V). Otherwise, we end up
5166     // with OpVariable instructions with Generic storage class which is not
5167     // allowed (SPIR-V V1.6 s3.42.8). Also, mapping literals to SPIR-V
5168     // UniformConstant storage class is not viable as pointers to it may not be
5169     // casted to Generic pointers which are used to model HIP's "flat" pointers.
5170     return LangAS::cuda_device;
5171   if (auto AS = getTarget().getConstantAddressSpace())
5172     return *AS;
5173   return LangAS::Default;
5174 }
5175 
5176 // In address space agnostic languages, string literals are in default address
5177 // space in AST. However, certain targets (e.g. amdgcn) request them to be
5178 // emitted in constant address space in LLVM IR. To be consistent with other
5179 // parts of AST, string literal global variables in constant address space
5180 // need to be casted to default address space before being put into address
5181 // map and referenced by other part of CodeGen.
5182 // In OpenCL, string literals are in constant address space in AST, therefore
5183 // they should not be casted to default address space.
5184 static llvm::Constant *
5185 castStringLiteralToDefaultAddressSpace(CodeGenModule &CGM,
5186                                        llvm::GlobalVariable *GV) {
5187   llvm::Constant *Cast = GV;
5188   if (!CGM.getLangOpts().OpenCL) {
5189     auto AS = CGM.GetGlobalConstantAddressSpace();
5190     if (AS != LangAS::Default)
5191       Cast = CGM.getTargetCodeGenInfo().performAddrSpaceCast(
5192           CGM, GV, AS, LangAS::Default,
5193           llvm::PointerType::get(
5194               CGM.getLLVMContext(),
5195               CGM.getContext().getTargetAddressSpace(LangAS::Default)));
5196   }
5197   return Cast;
5198 }
5199 
5200 template<typename SomeDecl>
5201 void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D,
5202                                                llvm::GlobalValue *GV) {
5203   if (!getLangOpts().CPlusPlus)
5204     return;
5205 
5206   // Must have 'used' attribute, or else inline assembly can't rely on
5207   // the name existing.
5208   if (!D->template hasAttr<UsedAttr>())
5209     return;
5210 
5211   // Must have internal linkage and an ordinary name.
5212   if (!D->getIdentifier() || D->getFormalLinkage() != Linkage::Internal)
5213     return;
5214 
5215   // Must be in an extern "C" context. Entities declared directly within
5216   // a record are not extern "C" even if the record is in such a context.
5217   const SomeDecl *First = D->getFirstDecl();
5218   if (First->getDeclContext()->isRecord() || !First->isInExternCContext())
5219     return;
5220 
5221   // OK, this is an internal linkage entity inside an extern "C" linkage
5222   // specification. Make a note of that so we can give it the "expected"
5223   // mangled name if nothing else is using that name.
5224   std::pair<StaticExternCMap::iterator, bool> R =
5225       StaticExternCValues.insert(std::make_pair(D->getIdentifier(), GV));
5226 
5227   // If we have multiple internal linkage entities with the same name
5228   // in extern "C" regions, none of them gets that name.
5229   if (!R.second)
5230     R.first->second = nullptr;
5231 }
5232 
5233 static bool shouldBeInCOMDAT(CodeGenModule &CGM, const Decl &D) {
5234   if (!CGM.supportsCOMDAT())
5235     return false;
5236 
5237   if (D.hasAttr<SelectAnyAttr>())
5238     return true;
5239 
5240   GVALinkage Linkage;
5241   if (auto *VD = dyn_cast<VarDecl>(&D))
5242     Linkage = CGM.getContext().GetGVALinkageForVariable(VD);
5243   else
5244     Linkage = CGM.getContext().GetGVALinkageForFunction(cast<FunctionDecl>(&D));
5245 
5246   switch (Linkage) {
5247   case GVA_Internal:
5248   case GVA_AvailableExternally:
5249   case GVA_StrongExternal:
5250     return false;
5251   case GVA_DiscardableODR:
5252   case GVA_StrongODR:
5253     return true;
5254   }
5255   llvm_unreachable("No such linkage");
5256 }
5257 
5258 bool CodeGenModule::supportsCOMDAT() const {
5259   return getTriple().supportsCOMDAT();
5260 }
5261 
5262 void CodeGenModule::maybeSetTrivialComdat(const Decl &D,
5263                                           llvm::GlobalObject &GO) {
5264   if (!shouldBeInCOMDAT(*this, D))
5265     return;
5266   GO.setComdat(TheModule.getOrInsertComdat(GO.getName()));
5267 }
5268 
5269 /// Pass IsTentative as true if you want to create a tentative definition.
5270 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
5271                                             bool IsTentative) {
5272   // OpenCL global variables of sampler type are translated to function calls,
5273   // therefore no need to be translated.
5274   QualType ASTTy = D->getType();
5275   if (getLangOpts().OpenCL && ASTTy->isSamplerT())
5276     return;
5277 
5278   // If this is OpenMP device, check if it is legal to emit this global
5279   // normally.
5280   if (LangOpts.OpenMPIsTargetDevice && OpenMPRuntime &&
5281       OpenMPRuntime->emitTargetGlobalVariable(D))
5282     return;
5283 
5284   llvm::TrackingVH<llvm::Constant> Init;
5285   bool NeedsGlobalCtor = false;
5286   // Whether the definition of the variable is available externally.
5287   // If yes, we shouldn't emit the GloablCtor and GlobalDtor for the variable
5288   // since this is the job for its original source.
5289   bool IsDefinitionAvailableExternally =
5290       getContext().GetGVALinkageForVariable(D) == GVA_AvailableExternally;
5291   bool NeedsGlobalDtor =
5292       !IsDefinitionAvailableExternally &&
5293       D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
5294 
5295   const VarDecl *InitDecl;
5296   const Expr *InitExpr = D->getAnyInitializer(InitDecl);
5297 
5298   std::optional<ConstantEmitter> emitter;
5299 
5300   // CUDA E.2.4.1 "__shared__ variables cannot have an initialization
5301   // as part of their declaration."  Sema has already checked for
5302   // error cases, so we just need to set Init to UndefValue.
5303   bool IsCUDASharedVar =
5304       getLangOpts().CUDAIsDevice && D->hasAttr<CUDASharedAttr>();
5305   // Shadows of initialized device-side global variables are also left
5306   // undefined.
5307   // Managed Variables should be initialized on both host side and device side.
5308   bool IsCUDAShadowVar =
5309       !getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
5310       (D->hasAttr<CUDAConstantAttr>() || D->hasAttr<CUDADeviceAttr>() ||
5311        D->hasAttr<CUDASharedAttr>());
5312   bool IsCUDADeviceShadowVar =
5313       getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
5314       (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
5315        D->getType()->isCUDADeviceBuiltinTextureType());
5316   if (getLangOpts().CUDA &&
5317       (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
5318     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
5319   else if (D->hasAttr<LoaderUninitializedAttr>())
5320     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
5321   else if (!InitExpr) {
5322     // This is a tentative definition; tentative definitions are
5323     // implicitly initialized with { 0 }.
5324     //
5325     // Note that tentative definitions are only emitted at the end of
5326     // a translation unit, so they should never have incomplete
5327     // type. In addition, EmitTentativeDefinition makes sure that we
5328     // never attempt to emit a tentative definition if a real one
5329     // exists. A use may still exists, however, so we still may need
5330     // to do a RAUW.
5331     assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
5332     Init = EmitNullConstant(D->getType());
5333   } else {
5334     initializedGlobalDecl = GlobalDecl(D);
5335     emitter.emplace(*this);
5336     llvm::Constant *Initializer = emitter->tryEmitForInitializer(*InitDecl);
5337     if (!Initializer) {
5338       QualType T = InitExpr->getType();
5339       if (D->getType()->isReferenceType())
5340         T = D->getType();
5341 
5342       if (getLangOpts().CPlusPlus) {
5343         if (InitDecl->hasFlexibleArrayInit(getContext()))
5344           ErrorUnsupported(D, "flexible array initializer");
5345         Init = EmitNullConstant(T);
5346 
5347         if (!IsDefinitionAvailableExternally)
5348           NeedsGlobalCtor = true;
5349       } else {
5350         ErrorUnsupported(D, "static initializer");
5351         Init = llvm::UndefValue::get(getTypes().ConvertType(T));
5352       }
5353     } else {
5354       Init = Initializer;
5355       // We don't need an initializer, so remove the entry for the delayed
5356       // initializer position (just in case this entry was delayed) if we
5357       // also don't need to register a destructor.
5358       if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
5359         DelayedCXXInitPosition.erase(D);
5360 
5361 #ifndef NDEBUG
5362       CharUnits VarSize = getContext().getTypeSizeInChars(ASTTy) +
5363                           InitDecl->getFlexibleArrayInitChars(getContext());
5364       CharUnits CstSize = CharUnits::fromQuantity(
5365           getDataLayout().getTypeAllocSize(Init->getType()));
5366       assert(VarSize == CstSize && "Emitted constant has unexpected size");
5367 #endif
5368     }
5369   }
5370 
5371   llvm::Type* InitType = Init->getType();
5372   llvm::Constant *Entry =
5373       GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative));
5374 
5375   // Strip off pointer casts if we got them.
5376   Entry = Entry->stripPointerCasts();
5377 
5378   // Entry is now either a Function or GlobalVariable.
5379   auto *GV = dyn_cast<llvm::GlobalVariable>(Entry);
5380 
5381   // We have a definition after a declaration with the wrong type.
5382   // We must make a new GlobalVariable* and update everything that used OldGV
5383   // (a declaration or tentative definition) with the new GlobalVariable*
5384   // (which will be a definition).
5385   //
5386   // This happens if there is a prototype for a global (e.g.
5387   // "extern int x[];") and then a definition of a different type (e.g.
5388   // "int x[10];"). This also happens when an initializer has a different type
5389   // from the type of the global (this happens with unions).
5390   if (!GV || GV->getValueType() != InitType ||
5391       GV->getType()->getAddressSpace() !=
5392           getContext().getTargetAddressSpace(GetGlobalVarAddressSpace(D))) {
5393 
5394     // Move the old entry aside so that we'll create a new one.
5395     Entry->setName(StringRef());
5396 
5397     // Make a new global with the correct type, this is now guaranteed to work.
5398     GV = cast<llvm::GlobalVariable>(
5399         GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative))
5400             ->stripPointerCasts());
5401 
5402     // Replace all uses of the old global with the new global
5403     llvm::Constant *NewPtrForOldDecl =
5404         llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV,
5405                                                              Entry->getType());
5406     Entry->replaceAllUsesWith(NewPtrForOldDecl);
5407 
5408     // Erase the old global, since it is no longer used.
5409     cast<llvm::GlobalValue>(Entry)->eraseFromParent();
5410   }
5411 
5412   MaybeHandleStaticInExternC(D, GV);
5413 
5414   if (D->hasAttr<AnnotateAttr>())
5415     AddGlobalAnnotations(D, GV);
5416 
5417   // Set the llvm linkage type as appropriate.
5418   llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(D);
5419 
5420   // CUDA B.2.1 "The __device__ qualifier declares a variable that resides on
5421   // the device. [...]"
5422   // CUDA B.2.2 "The __constant__ qualifier, optionally used together with
5423   // __device__, declares a variable that: [...]
5424   // Is accessible from all the threads within the grid and from the host
5425   // through the runtime library (cudaGetSymbolAddress() / cudaGetSymbolSize()
5426   // / cudaMemcpyToSymbol() / cudaMemcpyFromSymbol())."
5427   if (LangOpts.CUDA) {
5428     if (LangOpts.CUDAIsDevice) {
5429       if (Linkage != llvm::GlobalValue::InternalLinkage &&
5430           (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
5431            D->getType()->isCUDADeviceBuiltinSurfaceType() ||
5432            D->getType()->isCUDADeviceBuiltinTextureType()))
5433         GV->setExternallyInitialized(true);
5434     } else {
5435       getCUDARuntime().internalizeDeviceSideVar(D, Linkage);
5436     }
5437     getCUDARuntime().handleVarRegistration(D, *GV);
5438   }
5439 
5440   GV->setInitializer(Init);
5441   if (emitter)
5442     emitter->finalize(GV);
5443 
5444   // If it is safe to mark the global 'constant', do so now.
5445   GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor &&
5446                   D->getType().isConstantStorage(getContext(), true, true));
5447 
5448   // If it is in a read-only section, mark it 'constant'.
5449   if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
5450     const ASTContext::SectionInfo &SI = Context.SectionInfos[SA->getName()];
5451     if ((SI.SectionFlags & ASTContext::PSF_Write) == 0)
5452       GV->setConstant(true);
5453   }
5454 
5455   CharUnits AlignVal = getContext().getDeclAlign(D);
5456   // Check for alignment specifed in an 'omp allocate' directive.
5457   if (std::optional<CharUnits> AlignValFromAllocate =
5458           getOMPAllocateAlignment(D))
5459     AlignVal = *AlignValFromAllocate;
5460   GV->setAlignment(AlignVal.getAsAlign());
5461 
5462   // On Darwin, unlike other Itanium C++ ABI platforms, the thread-wrapper
5463   // function is only defined alongside the variable, not also alongside
5464   // callers. Normally, all accesses to a thread_local go through the
5465   // thread-wrapper in order to ensure initialization has occurred, underlying
5466   // variable will never be used other than the thread-wrapper, so it can be
5467   // converted to internal linkage.
5468   //
5469   // However, if the variable has the 'constinit' attribute, it _can_ be
5470   // referenced directly, without calling the thread-wrapper, so the linkage
5471   // must not be changed.
5472   //
5473   // Additionally, if the variable isn't plain external linkage, e.g. if it's
5474   // weak or linkonce, the de-duplication semantics are important to preserve,
5475   // so we don't change the linkage.
5476   if (D->getTLSKind() == VarDecl::TLS_Dynamic &&
5477       Linkage == llvm::GlobalValue::ExternalLinkage &&
5478       Context.getTargetInfo().getTriple().isOSDarwin() &&
5479       !D->hasAttr<ConstInitAttr>())
5480     Linkage = llvm::GlobalValue::InternalLinkage;
5481 
5482   GV->setLinkage(Linkage);
5483   if (D->hasAttr<DLLImportAttr>())
5484     GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
5485   else if (D->hasAttr<DLLExportAttr>())
5486     GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
5487   else
5488     GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
5489 
5490   if (Linkage == llvm::GlobalVariable::CommonLinkage) {
5491     // common vars aren't constant even if declared const.
5492     GV->setConstant(false);
5493     // Tentative definition of global variables may be initialized with
5494     // non-zero null pointers. In this case they should have weak linkage
5495     // since common linkage must have zero initializer and must not have
5496     // explicit section therefore cannot have non-zero initial value.
5497     if (!GV->getInitializer()->isNullValue())
5498       GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
5499   }
5500 
5501   setNonAliasAttributes(D, GV);
5502 
5503   if (D->getTLSKind() && !GV->isThreadLocal()) {
5504     if (D->getTLSKind() == VarDecl::TLS_Dynamic)
5505       CXXThreadLocals.push_back(D);
5506     setTLSMode(GV, *D);
5507   }
5508 
5509   maybeSetTrivialComdat(*D, *GV);
5510 
5511   // Emit the initializer function if necessary.
5512   if (NeedsGlobalCtor || NeedsGlobalDtor)
5513     EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
5514 
5515   SanitizerMD->reportGlobal(GV, *D, NeedsGlobalCtor);
5516 
5517   // Emit global variable debug information.
5518   if (CGDebugInfo *DI = getModuleDebugInfo())
5519     if (getCodeGenOpts().hasReducedDebugInfo())
5520       DI->EmitGlobalVariable(GV, D);
5521 }
5522 
5523 void CodeGenModule::EmitExternalVarDeclaration(const VarDecl *D) {
5524   if (CGDebugInfo *DI = getModuleDebugInfo())
5525     if (getCodeGenOpts().hasReducedDebugInfo()) {
5526       QualType ASTTy = D->getType();
5527       llvm::Type *Ty = getTypes().ConvertTypeForMem(D->getType());
5528       llvm::Constant *GV =
5529           GetOrCreateLLVMGlobal(D->getName(), Ty, ASTTy.getAddressSpace(), D);
5530       DI->EmitExternalVariable(
5531           cast<llvm::GlobalVariable>(GV->stripPointerCasts()), D);
5532     }
5533 }
5534 
5535 static bool isVarDeclStrongDefinition(const ASTContext &Context,
5536                                       CodeGenModule &CGM, const VarDecl *D,
5537                                       bool NoCommon) {
5538   // Don't give variables common linkage if -fno-common was specified unless it
5539   // was overridden by a NoCommon attribute.
5540   if ((NoCommon || D->hasAttr<NoCommonAttr>()) && !D->hasAttr<CommonAttr>())
5541     return true;
5542 
5543   // C11 6.9.2/2:
5544   //   A declaration of an identifier for an object that has file scope without
5545   //   an initializer, and without a storage-class specifier or with the
5546   //   storage-class specifier static, constitutes a tentative definition.
5547   if (D->getInit() || D->hasExternalStorage())
5548     return true;
5549 
5550   // A variable cannot be both common and exist in a section.
5551   if (D->hasAttr<SectionAttr>())
5552     return true;
5553 
5554   // A variable cannot be both common and exist in a section.
5555   // We don't try to determine which is the right section in the front-end.
5556   // If no specialized section name is applicable, it will resort to default.
5557   if (D->hasAttr<PragmaClangBSSSectionAttr>() ||
5558       D->hasAttr<PragmaClangDataSectionAttr>() ||
5559       D->hasAttr<PragmaClangRelroSectionAttr>() ||
5560       D->hasAttr<PragmaClangRodataSectionAttr>())
5561     return true;
5562 
5563   // Thread local vars aren't considered common linkage.
5564   if (D->getTLSKind())
5565     return true;
5566 
5567   // Tentative definitions marked with WeakImportAttr are true definitions.
5568   if (D->hasAttr<WeakImportAttr>())
5569     return true;
5570 
5571   // A variable cannot be both common and exist in a comdat.
5572   if (shouldBeInCOMDAT(CGM, *D))
5573     return true;
5574 
5575   // Declarations with a required alignment do not have common linkage in MSVC
5576   // mode.
5577   if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
5578     if (D->hasAttr<AlignedAttr>())
5579       return true;
5580     QualType VarType = D->getType();
5581     if (Context.isAlignmentRequired(VarType))
5582       return true;
5583 
5584     if (const auto *RT = VarType->getAs<RecordType>()) {
5585       const RecordDecl *RD = RT->getDecl();
5586       for (const FieldDecl *FD : RD->fields()) {
5587         if (FD->isBitField())
5588           continue;
5589         if (FD->hasAttr<AlignedAttr>())
5590           return true;
5591         if (Context.isAlignmentRequired(FD->getType()))
5592           return true;
5593       }
5594     }
5595   }
5596 
5597   // Microsoft's link.exe doesn't support alignments greater than 32 bytes for
5598   // common symbols, so symbols with greater alignment requirements cannot be
5599   // common.
5600   // Other COFF linkers (ld.bfd and LLD) support arbitrary power-of-two
5601   // alignments for common symbols via the aligncomm directive, so this
5602   // restriction only applies to MSVC environments.
5603   if (Context.getTargetInfo().getTriple().isKnownWindowsMSVCEnvironment() &&
5604       Context.getTypeAlignIfKnown(D->getType()) >
5605           Context.toBits(CharUnits::fromQuantity(32)))
5606     return true;
5607 
5608   return false;
5609 }
5610 
5611 llvm::GlobalValue::LinkageTypes
5612 CodeGenModule::getLLVMLinkageForDeclarator(const DeclaratorDecl *D,
5613                                            GVALinkage Linkage) {
5614   if (Linkage == GVA_Internal)
5615     return llvm::Function::InternalLinkage;
5616 
5617   if (D->hasAttr<WeakAttr>())
5618     return llvm::GlobalVariable::WeakAnyLinkage;
5619 
5620   if (const auto *FD = D->getAsFunction())
5621     if (FD->isMultiVersion() && Linkage == GVA_AvailableExternally)
5622       return llvm::GlobalVariable::LinkOnceAnyLinkage;
5623 
5624   // We are guaranteed to have a strong definition somewhere else,
5625   // so we can use available_externally linkage.
5626   if (Linkage == GVA_AvailableExternally)
5627     return llvm::GlobalValue::AvailableExternallyLinkage;
5628 
5629   // Note that Apple's kernel linker doesn't support symbol
5630   // coalescing, so we need to avoid linkonce and weak linkages there.
5631   // Normally, this means we just map to internal, but for explicit
5632   // instantiations we'll map to external.
5633 
5634   // In C++, the compiler has to emit a definition in every translation unit
5635   // that references the function.  We should use linkonce_odr because
5636   // a) if all references in this translation unit are optimized away, we
5637   // don't need to codegen it.  b) if the function persists, it needs to be
5638   // merged with other definitions. c) C++ has the ODR, so we know the
5639   // definition is dependable.
5640   if (Linkage == GVA_DiscardableODR)
5641     return !Context.getLangOpts().AppleKext ? llvm::Function::LinkOnceODRLinkage
5642                                             : llvm::Function::InternalLinkage;
5643 
5644   // An explicit instantiation of a template has weak linkage, since
5645   // explicit instantiations can occur in multiple translation units
5646   // and must all be equivalent. However, we are not allowed to
5647   // throw away these explicit instantiations.
5648   //
5649   // CUDA/HIP: For -fno-gpu-rdc case, device code is limited to one TU,
5650   // so say that CUDA templates are either external (for kernels) or internal.
5651   // This lets llvm perform aggressive inter-procedural optimizations. For
5652   // -fgpu-rdc case, device function calls across multiple TU's are allowed,
5653   // therefore we need to follow the normal linkage paradigm.
5654   if (Linkage == GVA_StrongODR) {
5655     if (getLangOpts().AppleKext)
5656       return llvm::Function::ExternalLinkage;
5657     if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
5658         !getLangOpts().GPURelocatableDeviceCode)
5659       return D->hasAttr<CUDAGlobalAttr>() ? llvm::Function::ExternalLinkage
5660                                           : llvm::Function::InternalLinkage;
5661     return llvm::Function::WeakODRLinkage;
5662   }
5663 
5664   // C++ doesn't have tentative definitions and thus cannot have common
5665   // linkage.
5666   if (!getLangOpts().CPlusPlus && isa<VarDecl>(D) &&
5667       !isVarDeclStrongDefinition(Context, *this, cast<VarDecl>(D),
5668                                  CodeGenOpts.NoCommon))
5669     return llvm::GlobalVariable::CommonLinkage;
5670 
5671   // selectany symbols are externally visible, so use weak instead of
5672   // linkonce.  MSVC optimizes away references to const selectany globals, so
5673   // all definitions should be the same and ODR linkage should be used.
5674   // http://msdn.microsoft.com/en-us/library/5tkz6s71.aspx
5675   if (D->hasAttr<SelectAnyAttr>())
5676     return llvm::GlobalVariable::WeakODRLinkage;
5677 
5678   // Otherwise, we have strong external linkage.
5679   assert(Linkage == GVA_StrongExternal);
5680   return llvm::GlobalVariable::ExternalLinkage;
5681 }
5682 
5683 llvm::GlobalValue::LinkageTypes
5684 CodeGenModule::getLLVMLinkageVarDefinition(const VarDecl *VD) {
5685   GVALinkage Linkage = getContext().GetGVALinkageForVariable(VD);
5686   return getLLVMLinkageForDeclarator(VD, Linkage);
5687 }
5688 
5689 /// Replace the uses of a function that was declared with a non-proto type.
5690 /// We want to silently drop extra arguments from call sites
5691 static void replaceUsesOfNonProtoConstant(llvm::Constant *old,
5692                                           llvm::Function *newFn) {
5693   // Fast path.
5694   if (old->use_empty()) return;
5695 
5696   llvm::Type *newRetTy = newFn->getReturnType();
5697   SmallVector<llvm::Value*, 4> newArgs;
5698 
5699   for (llvm::Value::use_iterator ui = old->use_begin(), ue = old->use_end();
5700          ui != ue; ) {
5701     llvm::Value::use_iterator use = ui++; // Increment before the use is erased.
5702     llvm::User *user = use->getUser();
5703 
5704     // Recognize and replace uses of bitcasts.  Most calls to
5705     // unprototyped functions will use bitcasts.
5706     if (auto *bitcast = dyn_cast<llvm::ConstantExpr>(user)) {
5707       if (bitcast->getOpcode() == llvm::Instruction::BitCast)
5708         replaceUsesOfNonProtoConstant(bitcast, newFn);
5709       continue;
5710     }
5711 
5712     // Recognize calls to the function.
5713     llvm::CallBase *callSite = dyn_cast<llvm::CallBase>(user);
5714     if (!callSite) continue;
5715     if (!callSite->isCallee(&*use))
5716       continue;
5717 
5718     // If the return types don't match exactly, then we can't
5719     // transform this call unless it's dead.
5720     if (callSite->getType() != newRetTy && !callSite->use_empty())
5721       continue;
5722 
5723     // Get the call site's attribute list.
5724     SmallVector<llvm::AttributeSet, 8> newArgAttrs;
5725     llvm::AttributeList oldAttrs = callSite->getAttributes();
5726 
5727     // If the function was passed too few arguments, don't transform.
5728     unsigned newNumArgs = newFn->arg_size();
5729     if (callSite->arg_size() < newNumArgs)
5730       continue;
5731 
5732     // If extra arguments were passed, we silently drop them.
5733     // If any of the types mismatch, we don't transform.
5734     unsigned argNo = 0;
5735     bool dontTransform = false;
5736     for (llvm::Argument &A : newFn->args()) {
5737       if (callSite->getArgOperand(argNo)->getType() != A.getType()) {
5738         dontTransform = true;
5739         break;
5740       }
5741 
5742       // Add any parameter attributes.
5743       newArgAttrs.push_back(oldAttrs.getParamAttrs(argNo));
5744       argNo++;
5745     }
5746     if (dontTransform)
5747       continue;
5748 
5749     // Okay, we can transform this.  Create the new call instruction and copy
5750     // over the required information.
5751     newArgs.append(callSite->arg_begin(), callSite->arg_begin() + argNo);
5752 
5753     // Copy over any operand bundles.
5754     SmallVector<llvm::OperandBundleDef, 1> newBundles;
5755     callSite->getOperandBundlesAsDefs(newBundles);
5756 
5757     llvm::CallBase *newCall;
5758     if (isa<llvm::CallInst>(callSite)) {
5759       newCall =
5760           llvm::CallInst::Create(newFn, newArgs, newBundles, "", callSite);
5761     } else {
5762       auto *oldInvoke = cast<llvm::InvokeInst>(callSite);
5763       newCall = llvm::InvokeInst::Create(newFn, oldInvoke->getNormalDest(),
5764                                          oldInvoke->getUnwindDest(), newArgs,
5765                                          newBundles, "", callSite);
5766     }
5767     newArgs.clear(); // for the next iteration
5768 
5769     if (!newCall->getType()->isVoidTy())
5770       newCall->takeName(callSite);
5771     newCall->setAttributes(
5772         llvm::AttributeList::get(newFn->getContext(), oldAttrs.getFnAttrs(),
5773                                  oldAttrs.getRetAttrs(), newArgAttrs));
5774     newCall->setCallingConv(callSite->getCallingConv());
5775 
5776     // Finally, remove the old call, replacing any uses with the new one.
5777     if (!callSite->use_empty())
5778       callSite->replaceAllUsesWith(newCall);
5779 
5780     // Copy debug location attached to CI.
5781     if (callSite->getDebugLoc())
5782       newCall->setDebugLoc(callSite->getDebugLoc());
5783 
5784     callSite->eraseFromParent();
5785   }
5786 }
5787 
5788 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
5789 /// implement a function with no prototype, e.g. "int foo() {}".  If there are
5790 /// existing call uses of the old function in the module, this adjusts them to
5791 /// call the new function directly.
5792 ///
5793 /// This is not just a cleanup: the always_inline pass requires direct calls to
5794 /// functions to be able to inline them.  If there is a bitcast in the way, it
5795 /// won't inline them.  Instcombine normally deletes these calls, but it isn't
5796 /// run at -O0.
5797 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
5798                                                       llvm::Function *NewFn) {
5799   // If we're redefining a global as a function, don't transform it.
5800   if (!isa<llvm::Function>(Old)) return;
5801 
5802   replaceUsesOfNonProtoConstant(Old, NewFn);
5803 }
5804 
5805 void CodeGenModule::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
5806   auto DK = VD->isThisDeclarationADefinition();
5807   if (DK == VarDecl::Definition && VD->hasAttr<DLLImportAttr>())
5808     return;
5809 
5810   TemplateSpecializationKind TSK = VD->getTemplateSpecializationKind();
5811   // If we have a definition, this might be a deferred decl. If the
5812   // instantiation is explicit, make sure we emit it at the end.
5813   if (VD->getDefinition() && TSK == TSK_ExplicitInstantiationDefinition)
5814     GetAddrOfGlobalVar(VD);
5815 
5816   EmitTopLevelDecl(VD);
5817 }
5818 
5819 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
5820                                                  llvm::GlobalValue *GV) {
5821   const auto *D = cast<FunctionDecl>(GD.getDecl());
5822 
5823   // Compute the function info and LLVM type.
5824   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
5825   llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
5826 
5827   // Get or create the prototype for the function.
5828   if (!GV || (GV->getValueType() != Ty))
5829     GV = cast<llvm::GlobalValue>(GetAddrOfFunction(GD, Ty, /*ForVTable=*/false,
5830                                                    /*DontDefer=*/true,
5831                                                    ForDefinition));
5832 
5833   // Already emitted.
5834   if (!GV->isDeclaration())
5835     return;
5836 
5837   // We need to set linkage and visibility on the function before
5838   // generating code for it because various parts of IR generation
5839   // want to propagate this information down (e.g. to local static
5840   // declarations).
5841   auto *Fn = cast<llvm::Function>(GV);
5842   setFunctionLinkage(GD, Fn);
5843 
5844   // FIXME: this is redundant with part of setFunctionDefinitionAttributes
5845   setGVProperties(Fn, GD);
5846 
5847   MaybeHandleStaticInExternC(D, Fn);
5848 
5849   maybeSetTrivialComdat(*D, *Fn);
5850 
5851   CodeGenFunction(*this).GenerateCode(GD, Fn, FI);
5852 
5853   setNonAliasAttributes(GD, Fn);
5854   SetLLVMFunctionAttributesForDefinition(D, Fn);
5855 
5856   if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
5857     AddGlobalCtor(Fn, CA->getPriority());
5858   if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
5859     AddGlobalDtor(Fn, DA->getPriority(), true);
5860   if (getLangOpts().OpenMP && D->hasAttr<OMPDeclareTargetDeclAttr>())
5861     getOpenMPRuntime().emitDeclareTargetFunction(D, GV);
5862 }
5863 
5864 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
5865   const auto *D = cast<ValueDecl>(GD.getDecl());
5866   const AliasAttr *AA = D->getAttr<AliasAttr>();
5867   assert(AA && "Not an alias?");
5868 
5869   StringRef MangledName = getMangledName(GD);
5870 
5871   if (AA->getAliasee() == MangledName) {
5872     Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
5873     return;
5874   }
5875 
5876   // If there is a definition in the module, then it wins over the alias.
5877   // This is dubious, but allow it to be safe.  Just ignore the alias.
5878   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
5879   if (Entry && !Entry->isDeclaration())
5880     return;
5881 
5882   Aliases.push_back(GD);
5883 
5884   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
5885 
5886   // Create a reference to the named value.  This ensures that it is emitted
5887   // if a deferred decl.
5888   llvm::Constant *Aliasee;
5889   llvm::GlobalValue::LinkageTypes LT;
5890   if (isa<llvm::FunctionType>(DeclTy)) {
5891     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GD,
5892                                       /*ForVTable=*/false);
5893     LT = getFunctionLinkage(GD);
5894   } else {
5895     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), DeclTy, LangAS::Default,
5896                                     /*D=*/nullptr);
5897     if (const auto *VD = dyn_cast<VarDecl>(GD.getDecl()))
5898       LT = getLLVMLinkageVarDefinition(VD);
5899     else
5900       LT = getFunctionLinkage(GD);
5901   }
5902 
5903   // Create the new alias itself, but don't set a name yet.
5904   unsigned AS = Aliasee->getType()->getPointerAddressSpace();
5905   auto *GA =
5906       llvm::GlobalAlias::create(DeclTy, AS, LT, "", Aliasee, &getModule());
5907 
5908   if (Entry) {
5909     if (GA->getAliasee() == Entry) {
5910       Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
5911       return;
5912     }
5913 
5914     assert(Entry->isDeclaration());
5915 
5916     // If there is a declaration in the module, then we had an extern followed
5917     // by the alias, as in:
5918     //   extern int test6();
5919     //   ...
5920     //   int test6() __attribute__((alias("test7")));
5921     //
5922     // Remove it and replace uses of it with the alias.
5923     GA->takeName(Entry);
5924 
5925     Entry->replaceAllUsesWith(GA);
5926     Entry->eraseFromParent();
5927   } else {
5928     GA->setName(MangledName);
5929   }
5930 
5931   // Set attributes which are particular to an alias; this is a
5932   // specialization of the attributes which may be set on a global
5933   // variable/function.
5934   if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakRefAttr>() ||
5935       D->isWeakImported()) {
5936     GA->setLinkage(llvm::Function::WeakAnyLinkage);
5937   }
5938 
5939   if (const auto *VD = dyn_cast<VarDecl>(D))
5940     if (VD->getTLSKind())
5941       setTLSMode(GA, *VD);
5942 
5943   SetCommonAttributes(GD, GA);
5944 
5945   // Emit global alias debug information.
5946   if (isa<VarDecl>(D))
5947     if (CGDebugInfo *DI = getModuleDebugInfo())
5948       DI->EmitGlobalAlias(cast<llvm::GlobalValue>(GA->getAliasee()->stripPointerCasts()), GD);
5949 }
5950 
5951 void CodeGenModule::emitIFuncDefinition(GlobalDecl GD) {
5952   const auto *D = cast<ValueDecl>(GD.getDecl());
5953   const IFuncAttr *IFA = D->getAttr<IFuncAttr>();
5954   assert(IFA && "Not an ifunc?");
5955 
5956   StringRef MangledName = getMangledName(GD);
5957 
5958   if (IFA->getResolver() == MangledName) {
5959     Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
5960     return;
5961   }
5962 
5963   // Report an error if some definition overrides ifunc.
5964   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
5965   if (Entry && !Entry->isDeclaration()) {
5966     GlobalDecl OtherGD;
5967     if (lookupRepresentativeDecl(MangledName, OtherGD) &&
5968         DiagnosedConflictingDefinitions.insert(GD).second) {
5969       Diags.Report(D->getLocation(), diag::err_duplicate_mangled_name)
5970           << MangledName;
5971       Diags.Report(OtherGD.getDecl()->getLocation(),
5972                    diag::note_previous_definition);
5973     }
5974     return;
5975   }
5976 
5977   Aliases.push_back(GD);
5978 
5979   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
5980   llvm::Type *ResolverTy = llvm::GlobalIFunc::getResolverFunctionType(DeclTy);
5981   llvm::Constant *Resolver =
5982       GetOrCreateLLVMFunction(IFA->getResolver(), ResolverTy, {},
5983                               /*ForVTable=*/false);
5984   llvm::GlobalIFunc *GIF =
5985       llvm::GlobalIFunc::create(DeclTy, 0, llvm::Function::ExternalLinkage,
5986                                 "", Resolver, &getModule());
5987   if (Entry) {
5988     if (GIF->getResolver() == Entry) {
5989       Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
5990       return;
5991     }
5992     assert(Entry->isDeclaration());
5993 
5994     // If there is a declaration in the module, then we had an extern followed
5995     // by the ifunc, as in:
5996     //   extern int test();
5997     //   ...
5998     //   int test() __attribute__((ifunc("resolver")));
5999     //
6000     // Remove it and replace uses of it with the ifunc.
6001     GIF->takeName(Entry);
6002 
6003     Entry->replaceAllUsesWith(GIF);
6004     Entry->eraseFromParent();
6005   } else
6006     GIF->setName(MangledName);
6007   if (auto *F = dyn_cast<llvm::Function>(Resolver)) {
6008     F->addFnAttr(llvm::Attribute::DisableSanitizerInstrumentation);
6009   }
6010   SetCommonAttributes(GD, GIF);
6011 }
6012 
6013 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,
6014                                             ArrayRef<llvm::Type*> Tys) {
6015   return llvm::Intrinsic::getDeclaration(&getModule(), (llvm::Intrinsic::ID)IID,
6016                                          Tys);
6017 }
6018 
6019 static llvm::StringMapEntry<llvm::GlobalVariable *> &
6020 GetConstantCFStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
6021                          const StringLiteral *Literal, bool TargetIsLSB,
6022                          bool &IsUTF16, unsigned &StringLength) {
6023   StringRef String = Literal->getString();
6024   unsigned NumBytes = String.size();
6025 
6026   // Check for simple case.
6027   if (!Literal->containsNonAsciiOrNull()) {
6028     StringLength = NumBytes;
6029     return *Map.insert(std::make_pair(String, nullptr)).first;
6030   }
6031 
6032   // Otherwise, convert the UTF8 literals into a string of shorts.
6033   IsUTF16 = true;
6034 
6035   SmallVector<llvm::UTF16, 128> ToBuf(NumBytes + 1); // +1 for ending nulls.
6036   const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)String.data();
6037   llvm::UTF16 *ToPtr = &ToBuf[0];
6038 
6039   (void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, &ToPtr,
6040                                  ToPtr + NumBytes, llvm::strictConversion);
6041 
6042   // ConvertUTF8toUTF16 returns the length in ToPtr.
6043   StringLength = ToPtr - &ToBuf[0];
6044 
6045   // Add an explicit null.
6046   *ToPtr = 0;
6047   return *Map.insert(std::make_pair(
6048                          StringRef(reinterpret_cast<const char *>(ToBuf.data()),
6049                                    (StringLength + 1) * 2),
6050                          nullptr)).first;
6051 }
6052 
6053 ConstantAddress
6054 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
6055   unsigned StringLength = 0;
6056   bool isUTF16 = false;
6057   llvm::StringMapEntry<llvm::GlobalVariable *> &Entry =
6058       GetConstantCFStringEntry(CFConstantStringMap, Literal,
6059                                getDataLayout().isLittleEndian(), isUTF16,
6060                                StringLength);
6061 
6062   if (auto *C = Entry.second)
6063     return ConstantAddress(
6064         C, C->getValueType(), CharUnits::fromQuantity(C->getAlignment()));
6065 
6066   llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty);
6067   llvm::Constant *Zeros[] = { Zero, Zero };
6068 
6069   const ASTContext &Context = getContext();
6070   const llvm::Triple &Triple = getTriple();
6071 
6072   const auto CFRuntime = getLangOpts().CFRuntime;
6073   const bool IsSwiftABI =
6074       static_cast<unsigned>(CFRuntime) >=
6075       static_cast<unsigned>(LangOptions::CoreFoundationABI::Swift);
6076   const bool IsSwift4_1 = CFRuntime == LangOptions::CoreFoundationABI::Swift4_1;
6077 
6078   // If we don't already have it, get __CFConstantStringClassReference.
6079   if (!CFConstantStringClassRef) {
6080     const char *CFConstantStringClassName = "__CFConstantStringClassReference";
6081     llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
6082     Ty = llvm::ArrayType::get(Ty, 0);
6083 
6084     switch (CFRuntime) {
6085     default: break;
6086     case LangOptions::CoreFoundationABI::Swift: [[fallthrough]];
6087     case LangOptions::CoreFoundationABI::Swift5_0:
6088       CFConstantStringClassName =
6089           Triple.isOSDarwin() ? "$s15SwiftFoundation19_NSCFConstantStringCN"
6090                               : "$s10Foundation19_NSCFConstantStringCN";
6091       Ty = IntPtrTy;
6092       break;
6093     case LangOptions::CoreFoundationABI::Swift4_2:
6094       CFConstantStringClassName =
6095           Triple.isOSDarwin() ? "$S15SwiftFoundation19_NSCFConstantStringCN"
6096                               : "$S10Foundation19_NSCFConstantStringCN";
6097       Ty = IntPtrTy;
6098       break;
6099     case LangOptions::CoreFoundationABI::Swift4_1:
6100       CFConstantStringClassName =
6101           Triple.isOSDarwin() ? "__T015SwiftFoundation19_NSCFConstantStringCN"
6102                               : "__T010Foundation19_NSCFConstantStringCN";
6103       Ty = IntPtrTy;
6104       break;
6105     }
6106 
6107     llvm::Constant *C = CreateRuntimeVariable(Ty, CFConstantStringClassName);
6108 
6109     if (Triple.isOSBinFormatELF() || Triple.isOSBinFormatCOFF()) {
6110       llvm::GlobalValue *GV = nullptr;
6111 
6112       if ((GV = dyn_cast<llvm::GlobalValue>(C))) {
6113         IdentifierInfo &II = Context.Idents.get(GV->getName());
6114         TranslationUnitDecl *TUDecl = Context.getTranslationUnitDecl();
6115         DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
6116 
6117         const VarDecl *VD = nullptr;
6118         for (const auto *Result : DC->lookup(&II))
6119           if ((VD = dyn_cast<VarDecl>(Result)))
6120             break;
6121 
6122         if (Triple.isOSBinFormatELF()) {
6123           if (!VD)
6124             GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
6125         } else {
6126           GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
6127           if (!VD || !VD->hasAttr<DLLExportAttr>())
6128             GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
6129           else
6130             GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
6131         }
6132 
6133         setDSOLocal(GV);
6134       }
6135     }
6136 
6137     // Decay array -> ptr
6138     CFConstantStringClassRef =
6139         IsSwiftABI ? llvm::ConstantExpr::getPtrToInt(C, Ty)
6140                    : llvm::ConstantExpr::getGetElementPtr(Ty, C, Zeros);
6141   }
6142 
6143   QualType CFTy = Context.getCFConstantStringType();
6144 
6145   auto *STy = cast<llvm::StructType>(getTypes().ConvertType(CFTy));
6146 
6147   ConstantInitBuilder Builder(*this);
6148   auto Fields = Builder.beginStruct(STy);
6149 
6150   // Class pointer.
6151   Fields.add(cast<llvm::Constant>(CFConstantStringClassRef));
6152 
6153   // Flags.
6154   if (IsSwiftABI) {
6155     Fields.addInt(IntPtrTy, IsSwift4_1 ? 0x05 : 0x01);
6156     Fields.addInt(Int64Ty, isUTF16 ? 0x07d0 : 0x07c8);
6157   } else {
6158     Fields.addInt(IntTy, isUTF16 ? 0x07d0 : 0x07C8);
6159   }
6160 
6161   // String pointer.
6162   llvm::Constant *C = nullptr;
6163   if (isUTF16) {
6164     auto Arr = llvm::ArrayRef(
6165         reinterpret_cast<uint16_t *>(const_cast<char *>(Entry.first().data())),
6166         Entry.first().size() / 2);
6167     C = llvm::ConstantDataArray::get(VMContext, Arr);
6168   } else {
6169     C = llvm::ConstantDataArray::getString(VMContext, Entry.first());
6170   }
6171 
6172   // Note: -fwritable-strings doesn't make the backing store strings of
6173   // CFStrings writable.
6174   auto *GV =
6175       new llvm::GlobalVariable(getModule(), C->getType(), /*isConstant=*/true,
6176                                llvm::GlobalValue::PrivateLinkage, C, ".str");
6177   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
6178   // Don't enforce the target's minimum global alignment, since the only use
6179   // of the string is via this class initializer.
6180   CharUnits Align = isUTF16 ? Context.getTypeAlignInChars(Context.ShortTy)
6181                             : Context.getTypeAlignInChars(Context.CharTy);
6182   GV->setAlignment(Align.getAsAlign());
6183 
6184   // FIXME: We set the section explicitly to avoid a bug in ld64 224.1.
6185   // Without it LLVM can merge the string with a non unnamed_addr one during
6186   // LTO.  Doing that changes the section it ends in, which surprises ld64.
6187   if (Triple.isOSBinFormatMachO())
6188     GV->setSection(isUTF16 ? "__TEXT,__ustring"
6189                            : "__TEXT,__cstring,cstring_literals");
6190   // Make sure the literal ends up in .rodata to allow for safe ICF and for
6191   // the static linker to adjust permissions to read-only later on.
6192   else if (Triple.isOSBinFormatELF())
6193     GV->setSection(".rodata");
6194 
6195   // String.
6196   llvm::Constant *Str =
6197       llvm::ConstantExpr::getGetElementPtr(GV->getValueType(), GV, Zeros);
6198 
6199   Fields.add(Str);
6200 
6201   // String length.
6202   llvm::IntegerType *LengthTy =
6203       llvm::IntegerType::get(getModule().getContext(),
6204                              Context.getTargetInfo().getLongWidth());
6205   if (IsSwiftABI) {
6206     if (CFRuntime == LangOptions::CoreFoundationABI::Swift4_1 ||
6207         CFRuntime == LangOptions::CoreFoundationABI::Swift4_2)
6208       LengthTy = Int32Ty;
6209     else
6210       LengthTy = IntPtrTy;
6211   }
6212   Fields.addInt(LengthTy, StringLength);
6213 
6214   // Swift ABI requires 8-byte alignment to ensure that the _Atomic(uint64_t) is
6215   // properly aligned on 32-bit platforms.
6216   CharUnits Alignment =
6217       IsSwiftABI ? Context.toCharUnitsFromBits(64) : getPointerAlign();
6218 
6219   // The struct.
6220   GV = Fields.finishAndCreateGlobal("_unnamed_cfstring_", Alignment,
6221                                     /*isConstant=*/false,
6222                                     llvm::GlobalVariable::PrivateLinkage);
6223   GV->addAttribute("objc_arc_inert");
6224   switch (Triple.getObjectFormat()) {
6225   case llvm::Triple::UnknownObjectFormat:
6226     llvm_unreachable("unknown file format");
6227   case llvm::Triple::DXContainer:
6228   case llvm::Triple::GOFF:
6229   case llvm::Triple::SPIRV:
6230   case llvm::Triple::XCOFF:
6231     llvm_unreachable("unimplemented");
6232   case llvm::Triple::COFF:
6233   case llvm::Triple::ELF:
6234   case llvm::Triple::Wasm:
6235     GV->setSection("cfstring");
6236     break;
6237   case llvm::Triple::MachO:
6238     GV->setSection("__DATA,__cfstring");
6239     break;
6240   }
6241   Entry.second = GV;
6242 
6243   return ConstantAddress(GV, GV->getValueType(), Alignment);
6244 }
6245 
6246 bool CodeGenModule::getExpressionLocationsEnabled() const {
6247   return !CodeGenOpts.EmitCodeView || CodeGenOpts.DebugColumnInfo;
6248 }
6249 
6250 QualType CodeGenModule::getObjCFastEnumerationStateType() {
6251   if (ObjCFastEnumerationStateType.isNull()) {
6252     RecordDecl *D = Context.buildImplicitRecord("__objcFastEnumerationState");
6253     D->startDefinition();
6254 
6255     QualType FieldTypes[] = {
6256         Context.UnsignedLongTy, Context.getPointerType(Context.getObjCIdType()),
6257         Context.getPointerType(Context.UnsignedLongTy),
6258         Context.getConstantArrayType(Context.UnsignedLongTy, llvm::APInt(32, 5),
6259                                      nullptr, ArraySizeModifier::Normal, 0)};
6260 
6261     for (size_t i = 0; i < 4; ++i) {
6262       FieldDecl *Field = FieldDecl::Create(Context,
6263                                            D,
6264                                            SourceLocation(),
6265                                            SourceLocation(), nullptr,
6266                                            FieldTypes[i], /*TInfo=*/nullptr,
6267                                            /*BitWidth=*/nullptr,
6268                                            /*Mutable=*/false,
6269                                            ICIS_NoInit);
6270       Field->setAccess(AS_public);
6271       D->addDecl(Field);
6272     }
6273 
6274     D->completeDefinition();
6275     ObjCFastEnumerationStateType = Context.getTagDeclType(D);
6276   }
6277 
6278   return ObjCFastEnumerationStateType;
6279 }
6280 
6281 llvm::Constant *
6282 CodeGenModule::GetConstantArrayFromStringLiteral(const StringLiteral *E) {
6283   assert(!E->getType()->isPointerType() && "Strings are always arrays");
6284 
6285   // Don't emit it as the address of the string, emit the string data itself
6286   // as an inline array.
6287   if (E->getCharByteWidth() == 1) {
6288     SmallString<64> Str(E->getString());
6289 
6290     // Resize the string to the right size, which is indicated by its type.
6291     const ConstantArrayType *CAT = Context.getAsConstantArrayType(E->getType());
6292     assert(CAT && "String literal not of constant array type!");
6293     Str.resize(CAT->getZExtSize());
6294     return llvm::ConstantDataArray::getString(VMContext, Str, false);
6295   }
6296 
6297   auto *AType = cast<llvm::ArrayType>(getTypes().ConvertType(E->getType()));
6298   llvm::Type *ElemTy = AType->getElementType();
6299   unsigned NumElements = AType->getNumElements();
6300 
6301   // Wide strings have either 2-byte or 4-byte elements.
6302   if (ElemTy->getPrimitiveSizeInBits() == 16) {
6303     SmallVector<uint16_t, 32> Elements;
6304     Elements.reserve(NumElements);
6305 
6306     for(unsigned i = 0, e = E->getLength(); i != e; ++i)
6307       Elements.push_back(E->getCodeUnit(i));
6308     Elements.resize(NumElements);
6309     return llvm::ConstantDataArray::get(VMContext, Elements);
6310   }
6311 
6312   assert(ElemTy->getPrimitiveSizeInBits() == 32);
6313   SmallVector<uint32_t, 32> Elements;
6314   Elements.reserve(NumElements);
6315 
6316   for(unsigned i = 0, e = E->getLength(); i != e; ++i)
6317     Elements.push_back(E->getCodeUnit(i));
6318   Elements.resize(NumElements);
6319   return llvm::ConstantDataArray::get(VMContext, Elements);
6320 }
6321 
6322 static llvm::GlobalVariable *
6323 GenerateStringLiteral(llvm::Constant *C, llvm::GlobalValue::LinkageTypes LT,
6324                       CodeGenModule &CGM, StringRef GlobalName,
6325                       CharUnits Alignment) {
6326   unsigned AddrSpace = CGM.getContext().getTargetAddressSpace(
6327       CGM.GetGlobalConstantAddressSpace());
6328 
6329   llvm::Module &M = CGM.getModule();
6330   // Create a global variable for this string
6331   auto *GV = new llvm::GlobalVariable(
6332       M, C->getType(), !CGM.getLangOpts().WritableStrings, LT, C, GlobalName,
6333       nullptr, llvm::GlobalVariable::NotThreadLocal, AddrSpace);
6334   GV->setAlignment(Alignment.getAsAlign());
6335   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
6336   if (GV->isWeakForLinker()) {
6337     assert(CGM.supportsCOMDAT() && "Only COFF uses weak string literals");
6338     GV->setComdat(M.getOrInsertComdat(GV->getName()));
6339   }
6340   CGM.setDSOLocal(GV);
6341 
6342   return GV;
6343 }
6344 
6345 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a
6346 /// constant array for the given string literal.
6347 ConstantAddress
6348 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S,
6349                                                   StringRef Name) {
6350   CharUnits Alignment =
6351       getContext().getAlignOfGlobalVarInChars(S->getType(), /*VD=*/nullptr);
6352 
6353   llvm::Constant *C = GetConstantArrayFromStringLiteral(S);
6354   llvm::GlobalVariable **Entry = nullptr;
6355   if (!LangOpts.WritableStrings) {
6356     Entry = &ConstantStringMap[C];
6357     if (auto GV = *Entry) {
6358       if (uint64_t(Alignment.getQuantity()) > GV->getAlignment())
6359         GV->setAlignment(Alignment.getAsAlign());
6360       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6361                              GV->getValueType(), Alignment);
6362     }
6363   }
6364 
6365   SmallString<256> MangledNameBuffer;
6366   StringRef GlobalVariableName;
6367   llvm::GlobalValue::LinkageTypes LT;
6368 
6369   // Mangle the string literal if that's how the ABI merges duplicate strings.
6370   // Don't do it if they are writable, since we don't want writes in one TU to
6371   // affect strings in another.
6372   if (getCXXABI().getMangleContext().shouldMangleStringLiteral(S) &&
6373       !LangOpts.WritableStrings) {
6374     llvm::raw_svector_ostream Out(MangledNameBuffer);
6375     getCXXABI().getMangleContext().mangleStringLiteral(S, Out);
6376     LT = llvm::GlobalValue::LinkOnceODRLinkage;
6377     GlobalVariableName = MangledNameBuffer;
6378   } else {
6379     LT = llvm::GlobalValue::PrivateLinkage;
6380     GlobalVariableName = Name;
6381   }
6382 
6383   auto GV = GenerateStringLiteral(C, LT, *this, GlobalVariableName, Alignment);
6384 
6385   CGDebugInfo *DI = getModuleDebugInfo();
6386   if (DI && getCodeGenOpts().hasReducedDebugInfo())
6387     DI->AddStringLiteralDebugInfo(GV, S);
6388 
6389   if (Entry)
6390     *Entry = GV;
6391 
6392   SanitizerMD->reportGlobal(GV, S->getStrTokenLoc(0), "<string literal>");
6393 
6394   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6395                          GV->getValueType(), Alignment);
6396 }
6397 
6398 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
6399 /// array for the given ObjCEncodeExpr node.
6400 ConstantAddress
6401 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
6402   std::string Str;
6403   getContext().getObjCEncodingForType(E->getEncodedType(), Str);
6404 
6405   return GetAddrOfConstantCString(Str);
6406 }
6407 
6408 /// GetAddrOfConstantCString - Returns a pointer to a character array containing
6409 /// the literal and a terminating '\0' character.
6410 /// The result has pointer to array type.
6411 ConstantAddress CodeGenModule::GetAddrOfConstantCString(
6412     const std::string &Str, const char *GlobalName) {
6413   StringRef StrWithNull(Str.c_str(), Str.size() + 1);
6414   CharUnits Alignment = getContext().getAlignOfGlobalVarInChars(
6415       getContext().CharTy, /*VD=*/nullptr);
6416 
6417   llvm::Constant *C =
6418       llvm::ConstantDataArray::getString(getLLVMContext(), StrWithNull, false);
6419 
6420   // Don't share any string literals if strings aren't constant.
6421   llvm::GlobalVariable **Entry = nullptr;
6422   if (!LangOpts.WritableStrings) {
6423     Entry = &ConstantStringMap[C];
6424     if (auto GV = *Entry) {
6425       if (uint64_t(Alignment.getQuantity()) > GV->getAlignment())
6426         GV->setAlignment(Alignment.getAsAlign());
6427       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6428                              GV->getValueType(), Alignment);
6429     }
6430   }
6431 
6432   // Get the default prefix if a name wasn't specified.
6433   if (!GlobalName)
6434     GlobalName = ".str";
6435   // Create a global variable for this.
6436   auto GV = GenerateStringLiteral(C, llvm::GlobalValue::PrivateLinkage, *this,
6437                                   GlobalName, Alignment);
6438   if (Entry)
6439     *Entry = GV;
6440 
6441   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6442                          GV->getValueType(), Alignment);
6443 }
6444 
6445 ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(
6446     const MaterializeTemporaryExpr *E, const Expr *Init) {
6447   assert((E->getStorageDuration() == SD_Static ||
6448           E->getStorageDuration() == SD_Thread) && "not a global temporary");
6449   const auto *VD = cast<VarDecl>(E->getExtendingDecl());
6450 
6451   // If we're not materializing a subobject of the temporary, keep the
6452   // cv-qualifiers from the type of the MaterializeTemporaryExpr.
6453   QualType MaterializedType = Init->getType();
6454   if (Init == E->getSubExpr())
6455     MaterializedType = E->getType();
6456 
6457   CharUnits Align = getContext().getTypeAlignInChars(MaterializedType);
6458 
6459   auto InsertResult = MaterializedGlobalTemporaryMap.insert({E, nullptr});
6460   if (!InsertResult.second) {
6461     // We've seen this before: either we already created it or we're in the
6462     // process of doing so.
6463     if (!InsertResult.first->second) {
6464       // We recursively re-entered this function, probably during emission of
6465       // the initializer. Create a placeholder. We'll clean this up in the
6466       // outer call, at the end of this function.
6467       llvm::Type *Type = getTypes().ConvertTypeForMem(MaterializedType);
6468       InsertResult.first->second = new llvm::GlobalVariable(
6469           getModule(), Type, false, llvm::GlobalVariable::InternalLinkage,
6470           nullptr);
6471     }
6472     return ConstantAddress(InsertResult.first->second,
6473                            llvm::cast<llvm::GlobalVariable>(
6474                                InsertResult.first->second->stripPointerCasts())
6475                                ->getValueType(),
6476                            Align);
6477   }
6478 
6479   // FIXME: If an externally-visible declaration extends multiple temporaries,
6480   // we need to give each temporary the same name in every translation unit (and
6481   // we also need to make the temporaries externally-visible).
6482   SmallString<256> Name;
6483   llvm::raw_svector_ostream Out(Name);
6484   getCXXABI().getMangleContext().mangleReferenceTemporary(
6485       VD, E->getManglingNumber(), Out);
6486 
6487   APValue *Value = nullptr;
6488   if (E->getStorageDuration() == SD_Static && VD->evaluateValue()) {
6489     // If the initializer of the extending declaration is a constant
6490     // initializer, we should have a cached constant initializer for this
6491     // temporary. Note that this might have a different value from the value
6492     // computed by evaluating the initializer if the surrounding constant
6493     // expression modifies the temporary.
6494     Value = E->getOrCreateValue(false);
6495   }
6496 
6497   // Try evaluating it now, it might have a constant initializer.
6498   Expr::EvalResult EvalResult;
6499   if (!Value && Init->EvaluateAsRValue(EvalResult, getContext()) &&
6500       !EvalResult.hasSideEffects())
6501     Value = &EvalResult.Val;
6502 
6503   LangAS AddrSpace = GetGlobalVarAddressSpace(VD);
6504 
6505   std::optional<ConstantEmitter> emitter;
6506   llvm::Constant *InitialValue = nullptr;
6507   bool Constant = false;
6508   llvm::Type *Type;
6509   if (Value) {
6510     // The temporary has a constant initializer, use it.
6511     emitter.emplace(*this);
6512     InitialValue = emitter->emitForInitializer(*Value, AddrSpace,
6513                                                MaterializedType);
6514     Constant =
6515         MaterializedType.isConstantStorage(getContext(), /*ExcludeCtor*/ Value,
6516                                            /*ExcludeDtor*/ false);
6517     Type = InitialValue->getType();
6518   } else {
6519     // No initializer, the initialization will be provided when we
6520     // initialize the declaration which performed lifetime extension.
6521     Type = getTypes().ConvertTypeForMem(MaterializedType);
6522   }
6523 
6524   // Create a global variable for this lifetime-extended temporary.
6525   llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(VD);
6526   if (Linkage == llvm::GlobalVariable::ExternalLinkage) {
6527     const VarDecl *InitVD;
6528     if (VD->isStaticDataMember() && VD->getAnyInitializer(InitVD) &&
6529         isa<CXXRecordDecl>(InitVD->getLexicalDeclContext())) {
6530       // Temporaries defined inside a class get linkonce_odr linkage because the
6531       // class can be defined in multiple translation units.
6532       Linkage = llvm::GlobalVariable::LinkOnceODRLinkage;
6533     } else {
6534       // There is no need for this temporary to have external linkage if the
6535       // VarDecl has external linkage.
6536       Linkage = llvm::GlobalVariable::InternalLinkage;
6537     }
6538   }
6539   auto TargetAS = getContext().getTargetAddressSpace(AddrSpace);
6540   auto *GV = new llvm::GlobalVariable(
6541       getModule(), Type, Constant, Linkage, InitialValue, Name.c_str(),
6542       /*InsertBefore=*/nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
6543   if (emitter) emitter->finalize(GV);
6544   // Don't assign dllimport or dllexport to local linkage globals.
6545   if (!llvm::GlobalValue::isLocalLinkage(Linkage)) {
6546     setGVProperties(GV, VD);
6547     if (GV->getDLLStorageClass() == llvm::GlobalVariable::DLLExportStorageClass)
6548       // The reference temporary should never be dllexport.
6549       GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
6550   }
6551   GV->setAlignment(Align.getAsAlign());
6552   if (supportsCOMDAT() && GV->isWeakForLinker())
6553     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
6554   if (VD->getTLSKind())
6555     setTLSMode(GV, *VD);
6556   llvm::Constant *CV = GV;
6557   if (AddrSpace != LangAS::Default)
6558     CV = getTargetCodeGenInfo().performAddrSpaceCast(
6559         *this, GV, AddrSpace, LangAS::Default,
6560         llvm::PointerType::get(
6561             getLLVMContext(),
6562             getContext().getTargetAddressSpace(LangAS::Default)));
6563 
6564   // Update the map with the new temporary. If we created a placeholder above,
6565   // replace it with the new global now.
6566   llvm::Constant *&Entry = MaterializedGlobalTemporaryMap[E];
6567   if (Entry) {
6568     Entry->replaceAllUsesWith(CV);
6569     llvm::cast<llvm::GlobalVariable>(Entry)->eraseFromParent();
6570   }
6571   Entry = CV;
6572 
6573   return ConstantAddress(CV, Type, Align);
6574 }
6575 
6576 /// EmitObjCPropertyImplementations - Emit information for synthesized
6577 /// properties for an implementation.
6578 void CodeGenModule::EmitObjCPropertyImplementations(const
6579                                                     ObjCImplementationDecl *D) {
6580   for (const auto *PID : D->property_impls()) {
6581     // Dynamic is just for type-checking.
6582     if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
6583       ObjCPropertyDecl *PD = PID->getPropertyDecl();
6584 
6585       // Determine which methods need to be implemented, some may have
6586       // been overridden. Note that ::isPropertyAccessor is not the method
6587       // we want, that just indicates if the decl came from a
6588       // property. What we want to know is if the method is defined in
6589       // this implementation.
6590       auto *Getter = PID->getGetterMethodDecl();
6591       if (!Getter || Getter->isSynthesizedAccessorStub())
6592         CodeGenFunction(*this).GenerateObjCGetter(
6593             const_cast<ObjCImplementationDecl *>(D), PID);
6594       auto *Setter = PID->getSetterMethodDecl();
6595       if (!PD->isReadOnly() && (!Setter || Setter->isSynthesizedAccessorStub()))
6596         CodeGenFunction(*this).GenerateObjCSetter(
6597                                  const_cast<ObjCImplementationDecl *>(D), PID);
6598     }
6599   }
6600 }
6601 
6602 static bool needsDestructMethod(ObjCImplementationDecl *impl) {
6603   const ObjCInterfaceDecl *iface = impl->getClassInterface();
6604   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
6605        ivar; ivar = ivar->getNextIvar())
6606     if (ivar->getType().isDestructedType())
6607       return true;
6608 
6609   return false;
6610 }
6611 
6612 static bool AllTrivialInitializers(CodeGenModule &CGM,
6613                                    ObjCImplementationDecl *D) {
6614   CodeGenFunction CGF(CGM);
6615   for (ObjCImplementationDecl::init_iterator B = D->init_begin(),
6616        E = D->init_end(); B != E; ++B) {
6617     CXXCtorInitializer *CtorInitExp = *B;
6618     Expr *Init = CtorInitExp->getInit();
6619     if (!CGF.isTrivialInitializer(Init))
6620       return false;
6621   }
6622   return true;
6623 }
6624 
6625 /// EmitObjCIvarInitializations - Emit information for ivar initialization
6626 /// for an implementation.
6627 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
6628   // We might need a .cxx_destruct even if we don't have any ivar initializers.
6629   if (needsDestructMethod(D)) {
6630     const IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct");
6631     Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
6632     ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(
6633         getContext(), D->getLocation(), D->getLocation(), cxxSelector,
6634         getContext().VoidTy, nullptr, D,
6635         /*isInstance=*/true, /*isVariadic=*/false,
6636         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
6637         /*isImplicitlyDeclared=*/true,
6638         /*isDefined=*/false, ObjCImplementationControl::Required);
6639     D->addInstanceMethod(DTORMethod);
6640     CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false);
6641     D->setHasDestructors(true);
6642   }
6643 
6644   // If the implementation doesn't have any ivar initializers, we don't need
6645   // a .cxx_construct.
6646   if (D->getNumIvarInitializers() == 0 ||
6647       AllTrivialInitializers(*this, D))
6648     return;
6649 
6650   const IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
6651   Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
6652   // The constructor returns 'self'.
6653   ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(
6654       getContext(), D->getLocation(), D->getLocation(), cxxSelector,
6655       getContext().getObjCIdType(), nullptr, D, /*isInstance=*/true,
6656       /*isVariadic=*/false,
6657       /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
6658       /*isImplicitlyDeclared=*/true,
6659       /*isDefined=*/false, ObjCImplementationControl::Required);
6660   D->addInstanceMethod(CTORMethod);
6661   CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true);
6662   D->setHasNonZeroConstructors(true);
6663 }
6664 
6665 // EmitLinkageSpec - Emit all declarations in a linkage spec.
6666 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
6667   if (LSD->getLanguage() != LinkageSpecLanguageIDs::C &&
6668       LSD->getLanguage() != LinkageSpecLanguageIDs::CXX) {
6669     ErrorUnsupported(LSD, "linkage spec");
6670     return;
6671   }
6672 
6673   EmitDeclContext(LSD);
6674 }
6675 
6676 void CodeGenModule::EmitTopLevelStmt(const TopLevelStmtDecl *D) {
6677   // Device code should not be at top level.
6678   if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
6679     return;
6680 
6681   std::unique_ptr<CodeGenFunction> &CurCGF =
6682       GlobalTopLevelStmtBlockInFlight.first;
6683 
6684   // We emitted a top-level stmt but after it there is initialization.
6685   // Stop squashing the top-level stmts into a single function.
6686   if (CurCGF && CXXGlobalInits.back() != CurCGF->CurFn) {
6687     CurCGF->FinishFunction(D->getEndLoc());
6688     CurCGF = nullptr;
6689   }
6690 
6691   if (!CurCGF) {
6692     // void __stmts__N(void)
6693     // FIXME: Ask the ABI name mangler to pick a name.
6694     std::string Name = "__stmts__" + llvm::utostr(CXXGlobalInits.size());
6695     FunctionArgList Args;
6696     QualType RetTy = getContext().VoidTy;
6697     const CGFunctionInfo &FnInfo =
6698         getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
6699     llvm::FunctionType *FnTy = getTypes().GetFunctionType(FnInfo);
6700     llvm::Function *Fn = llvm::Function::Create(
6701         FnTy, llvm::GlobalValue::InternalLinkage, Name, &getModule());
6702 
6703     CurCGF.reset(new CodeGenFunction(*this));
6704     GlobalTopLevelStmtBlockInFlight.second = D;
6705     CurCGF->StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
6706                           D->getBeginLoc(), D->getBeginLoc());
6707     CXXGlobalInits.push_back(Fn);
6708   }
6709 
6710   CurCGF->EmitStmt(D->getStmt());
6711 }
6712 
6713 void CodeGenModule::EmitDeclContext(const DeclContext *DC) {
6714   for (auto *I : DC->decls()) {
6715     // Unlike other DeclContexts, the contents of an ObjCImplDecl at TU scope
6716     // are themselves considered "top-level", so EmitTopLevelDecl on an
6717     // ObjCImplDecl does not recursively visit them. We need to do that in
6718     // case they're nested inside another construct (LinkageSpecDecl /
6719     // ExportDecl) that does stop them from being considered "top-level".
6720     if (auto *OID = dyn_cast<ObjCImplDecl>(I)) {
6721       for (auto *M : OID->methods())
6722         EmitTopLevelDecl(M);
6723     }
6724 
6725     EmitTopLevelDecl(I);
6726   }
6727 }
6728 
6729 /// EmitTopLevelDecl - Emit code for a single top level declaration.
6730 void CodeGenModule::EmitTopLevelDecl(Decl *D) {
6731   // Ignore dependent declarations.
6732   if (D->isTemplated())
6733     return;
6734 
6735   // Consteval function shouldn't be emitted.
6736   if (auto *FD = dyn_cast<FunctionDecl>(D); FD && FD->isImmediateFunction())
6737     return;
6738 
6739   switch (D->getKind()) {
6740   case Decl::CXXConversion:
6741   case Decl::CXXMethod:
6742   case Decl::Function:
6743     EmitGlobal(cast<FunctionDecl>(D));
6744     // Always provide some coverage mapping
6745     // even for the functions that aren't emitted.
6746     AddDeferredUnusedCoverageMapping(D);
6747     break;
6748 
6749   case Decl::CXXDeductionGuide:
6750     // Function-like, but does not result in code emission.
6751     break;
6752 
6753   case Decl::Var:
6754   case Decl::Decomposition:
6755   case Decl::VarTemplateSpecialization:
6756     EmitGlobal(cast<VarDecl>(D));
6757     if (auto *DD = dyn_cast<DecompositionDecl>(D))
6758       for (auto *B : DD->bindings())
6759         if (auto *HD = B->getHoldingVar())
6760           EmitGlobal(HD);
6761     break;
6762 
6763   // Indirect fields from global anonymous structs and unions can be
6764   // ignored; only the actual variable requires IR gen support.
6765   case Decl::IndirectField:
6766     break;
6767 
6768   // C++ Decls
6769   case Decl::Namespace:
6770     EmitDeclContext(cast<NamespaceDecl>(D));
6771     break;
6772   case Decl::ClassTemplateSpecialization: {
6773     const auto *Spec = cast<ClassTemplateSpecializationDecl>(D);
6774     if (CGDebugInfo *DI = getModuleDebugInfo())
6775       if (Spec->getSpecializationKind() ==
6776               TSK_ExplicitInstantiationDefinition &&
6777           Spec->hasDefinition())
6778         DI->completeTemplateDefinition(*Spec);
6779   } [[fallthrough]];
6780   case Decl::CXXRecord: {
6781     CXXRecordDecl *CRD = cast<CXXRecordDecl>(D);
6782     if (CGDebugInfo *DI = getModuleDebugInfo()) {
6783       if (CRD->hasDefinition())
6784         DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
6785       if (auto *ES = D->getASTContext().getExternalSource())
6786         if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
6787           DI->completeUnusedClass(*CRD);
6788     }
6789     // Emit any static data members, they may be definitions.
6790     for (auto *I : CRD->decls())
6791       if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))
6792         EmitTopLevelDecl(I);
6793     break;
6794   }
6795     // No code generation needed.
6796   case Decl::UsingShadow:
6797   case Decl::ClassTemplate:
6798   case Decl::VarTemplate:
6799   case Decl::Concept:
6800   case Decl::VarTemplatePartialSpecialization:
6801   case Decl::FunctionTemplate:
6802   case Decl::TypeAliasTemplate:
6803   case Decl::Block:
6804   case Decl::Empty:
6805   case Decl::Binding:
6806     break;
6807   case Decl::Using:          // using X; [C++]
6808     if (CGDebugInfo *DI = getModuleDebugInfo())
6809         DI->EmitUsingDecl(cast<UsingDecl>(*D));
6810     break;
6811   case Decl::UsingEnum: // using enum X; [C++]
6812     if (CGDebugInfo *DI = getModuleDebugInfo())
6813       DI->EmitUsingEnumDecl(cast<UsingEnumDecl>(*D));
6814     break;
6815   case Decl::NamespaceAlias:
6816     if (CGDebugInfo *DI = getModuleDebugInfo())
6817         DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(*D));
6818     break;
6819   case Decl::UsingDirective: // using namespace X; [C++]
6820     if (CGDebugInfo *DI = getModuleDebugInfo())
6821       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D));
6822     break;
6823   case Decl::CXXConstructor:
6824     getCXXABI().EmitCXXConstructors(cast<CXXConstructorDecl>(D));
6825     break;
6826   case Decl::CXXDestructor:
6827     getCXXABI().EmitCXXDestructors(cast<CXXDestructorDecl>(D));
6828     break;
6829 
6830   case Decl::StaticAssert:
6831     // Nothing to do.
6832     break;
6833 
6834   // Objective-C Decls
6835 
6836   // Forward declarations, no (immediate) code generation.
6837   case Decl::ObjCInterface:
6838   case Decl::ObjCCategory:
6839     break;
6840 
6841   case Decl::ObjCProtocol: {
6842     auto *Proto = cast<ObjCProtocolDecl>(D);
6843     if (Proto->isThisDeclarationADefinition())
6844       ObjCRuntime->GenerateProtocol(Proto);
6845     break;
6846   }
6847 
6848   case Decl::ObjCCategoryImpl:
6849     // Categories have properties but don't support synthesize so we
6850     // can ignore them here.
6851     ObjCRuntime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
6852     break;
6853 
6854   case Decl::ObjCImplementation: {
6855     auto *OMD = cast<ObjCImplementationDecl>(D);
6856     EmitObjCPropertyImplementations(OMD);
6857     EmitObjCIvarInitializations(OMD);
6858     ObjCRuntime->GenerateClass(OMD);
6859     // Emit global variable debug information.
6860     if (CGDebugInfo *DI = getModuleDebugInfo())
6861       if (getCodeGenOpts().hasReducedDebugInfo())
6862         DI->getOrCreateInterfaceType(getContext().getObjCInterfaceType(
6863             OMD->getClassInterface()), OMD->getLocation());
6864     break;
6865   }
6866   case Decl::ObjCMethod: {
6867     auto *OMD = cast<ObjCMethodDecl>(D);
6868     // If this is not a prototype, emit the body.
6869     if (OMD->getBody())
6870       CodeGenFunction(*this).GenerateObjCMethod(OMD);
6871     break;
6872   }
6873   case Decl::ObjCCompatibleAlias:
6874     ObjCRuntime->RegisterAlias(cast<ObjCCompatibleAliasDecl>(D));
6875     break;
6876 
6877   case Decl::PragmaComment: {
6878     const auto *PCD = cast<PragmaCommentDecl>(D);
6879     switch (PCD->getCommentKind()) {
6880     case PCK_Unknown:
6881       llvm_unreachable("unexpected pragma comment kind");
6882     case PCK_Linker:
6883       AppendLinkerOptions(PCD->getArg());
6884       break;
6885     case PCK_Lib:
6886         AddDependentLib(PCD->getArg());
6887       break;
6888     case PCK_Compiler:
6889     case PCK_ExeStr:
6890     case PCK_User:
6891       break; // We ignore all of these.
6892     }
6893     break;
6894   }
6895 
6896   case Decl::PragmaDetectMismatch: {
6897     const auto *PDMD = cast<PragmaDetectMismatchDecl>(D);
6898     AddDetectMismatch(PDMD->getName(), PDMD->getValue());
6899     break;
6900   }
6901 
6902   case Decl::LinkageSpec:
6903     EmitLinkageSpec(cast<LinkageSpecDecl>(D));
6904     break;
6905 
6906   case Decl::FileScopeAsm: {
6907     // File-scope asm is ignored during device-side CUDA compilation.
6908     if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
6909       break;
6910     // File-scope asm is ignored during device-side OpenMP compilation.
6911     if (LangOpts.OpenMPIsTargetDevice)
6912       break;
6913     // File-scope asm is ignored during device-side SYCL compilation.
6914     if (LangOpts.SYCLIsDevice)
6915       break;
6916     auto *AD = cast<FileScopeAsmDecl>(D);
6917     getModule().appendModuleInlineAsm(AD->getAsmString()->getString());
6918     break;
6919   }
6920 
6921   case Decl::TopLevelStmt:
6922     EmitTopLevelStmt(cast<TopLevelStmtDecl>(D));
6923     break;
6924 
6925   case Decl::Import: {
6926     auto *Import = cast<ImportDecl>(D);
6927 
6928     // If we've already imported this module, we're done.
6929     if (!ImportedModules.insert(Import->getImportedModule()))
6930       break;
6931 
6932     // Emit debug information for direct imports.
6933     if (!Import->getImportedOwningModule()) {
6934       if (CGDebugInfo *DI = getModuleDebugInfo())
6935         DI->EmitImportDecl(*Import);
6936     }
6937 
6938     // For C++ standard modules we are done - we will call the module
6939     // initializer for imported modules, and that will likewise call those for
6940     // any imports it has.
6941     if (CXX20ModuleInits && Import->getImportedOwningModule() &&
6942         !Import->getImportedOwningModule()->isModuleMapModule())
6943       break;
6944 
6945     // For clang C++ module map modules the initializers for sub-modules are
6946     // emitted here.
6947 
6948     // Find all of the submodules and emit the module initializers.
6949     llvm::SmallPtrSet<clang::Module *, 16> Visited;
6950     SmallVector<clang::Module *, 16> Stack;
6951     Visited.insert(Import->getImportedModule());
6952     Stack.push_back(Import->getImportedModule());
6953 
6954     while (!Stack.empty()) {
6955       clang::Module *Mod = Stack.pop_back_val();
6956       if (!EmittedModuleInitializers.insert(Mod).second)
6957         continue;
6958 
6959       for (auto *D : Context.getModuleInitializers(Mod))
6960         EmitTopLevelDecl(D);
6961 
6962       // Visit the submodules of this module.
6963       for (auto *Submodule : Mod->submodules()) {
6964         // Skip explicit children; they need to be explicitly imported to emit
6965         // the initializers.
6966         if (Submodule->IsExplicit)
6967           continue;
6968 
6969         if (Visited.insert(Submodule).second)
6970           Stack.push_back(Submodule);
6971       }
6972     }
6973     break;
6974   }
6975 
6976   case Decl::Export:
6977     EmitDeclContext(cast<ExportDecl>(D));
6978     break;
6979 
6980   case Decl::OMPThreadPrivate:
6981     EmitOMPThreadPrivateDecl(cast<OMPThreadPrivateDecl>(D));
6982     break;
6983 
6984   case Decl::OMPAllocate:
6985     EmitOMPAllocateDecl(cast<OMPAllocateDecl>(D));
6986     break;
6987 
6988   case Decl::OMPDeclareReduction:
6989     EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(D));
6990     break;
6991 
6992   case Decl::OMPDeclareMapper:
6993     EmitOMPDeclareMapper(cast<OMPDeclareMapperDecl>(D));
6994     break;
6995 
6996   case Decl::OMPRequires:
6997     EmitOMPRequiresDecl(cast<OMPRequiresDecl>(D));
6998     break;
6999 
7000   case Decl::Typedef:
7001   case Decl::TypeAlias: // using foo = bar; [C++11]
7002     if (CGDebugInfo *DI = getModuleDebugInfo())
7003       DI->EmitAndRetainType(
7004           getContext().getTypedefType(cast<TypedefNameDecl>(D)));
7005     break;
7006 
7007   case Decl::Record:
7008     if (CGDebugInfo *DI = getModuleDebugInfo())
7009       if (cast<RecordDecl>(D)->getDefinition())
7010         DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
7011     break;
7012 
7013   case Decl::Enum:
7014     if (CGDebugInfo *DI = getModuleDebugInfo())
7015       if (cast<EnumDecl>(D)->getDefinition())
7016         DI->EmitAndRetainType(getContext().getEnumType(cast<EnumDecl>(D)));
7017     break;
7018 
7019   case Decl::HLSLBuffer:
7020     getHLSLRuntime().addBuffer(cast<HLSLBufferDecl>(D));
7021     break;
7022 
7023   default:
7024     // Make sure we handled everything we should, every other kind is a
7025     // non-top-level decl.  FIXME: Would be nice to have an isTopLevelDeclKind
7026     // function. Need to recode Decl::Kind to do that easily.
7027     assert(isa<TypeDecl>(D) && "Unsupported decl kind");
7028     break;
7029   }
7030 }
7031 
7032 void CodeGenModule::AddDeferredUnusedCoverageMapping(Decl *D) {
7033   // Do we need to generate coverage mapping?
7034   if (!CodeGenOpts.CoverageMapping)
7035     return;
7036   switch (D->getKind()) {
7037   case Decl::CXXConversion:
7038   case Decl::CXXMethod:
7039   case Decl::Function:
7040   case Decl::ObjCMethod:
7041   case Decl::CXXConstructor:
7042   case Decl::CXXDestructor: {
7043     if (!cast<FunctionDecl>(D)->doesThisDeclarationHaveABody())
7044       break;
7045     SourceManager &SM = getContext().getSourceManager();
7046     if (LimitedCoverage && SM.getMainFileID() != SM.getFileID(D->getBeginLoc()))
7047       break;
7048     DeferredEmptyCoverageMappingDecls.try_emplace(D, true);
7049     break;
7050   }
7051   default:
7052     break;
7053   };
7054 }
7055 
7056 void CodeGenModule::ClearUnusedCoverageMapping(const Decl *D) {
7057   // Do we need to generate coverage mapping?
7058   if (!CodeGenOpts.CoverageMapping)
7059     return;
7060   if (const auto *Fn = dyn_cast<FunctionDecl>(D)) {
7061     if (Fn->isTemplateInstantiation())
7062       ClearUnusedCoverageMapping(Fn->getTemplateInstantiationPattern());
7063   }
7064   DeferredEmptyCoverageMappingDecls.insert_or_assign(D, false);
7065 }
7066 
7067 void CodeGenModule::EmitDeferredUnusedCoverageMappings() {
7068   // We call takeVector() here to avoid use-after-free.
7069   // FIXME: DeferredEmptyCoverageMappingDecls is getting mutated because
7070   // we deserialize function bodies to emit coverage info for them, and that
7071   // deserializes more declarations. How should we handle that case?
7072   for (const auto &Entry : DeferredEmptyCoverageMappingDecls.takeVector()) {
7073     if (!Entry.second)
7074       continue;
7075     const Decl *D = Entry.first;
7076     switch (D->getKind()) {
7077     case Decl::CXXConversion:
7078     case Decl::CXXMethod:
7079     case Decl::Function:
7080     case Decl::ObjCMethod: {
7081       CodeGenPGO PGO(*this);
7082       GlobalDecl GD(cast<FunctionDecl>(D));
7083       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
7084                                   getFunctionLinkage(GD));
7085       break;
7086     }
7087     case Decl::CXXConstructor: {
7088       CodeGenPGO PGO(*this);
7089       GlobalDecl GD(cast<CXXConstructorDecl>(D), Ctor_Base);
7090       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
7091                                   getFunctionLinkage(GD));
7092       break;
7093     }
7094     case Decl::CXXDestructor: {
7095       CodeGenPGO PGO(*this);
7096       GlobalDecl GD(cast<CXXDestructorDecl>(D), Dtor_Base);
7097       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
7098                                   getFunctionLinkage(GD));
7099       break;
7100     }
7101     default:
7102       break;
7103     };
7104   }
7105 }
7106 
7107 void CodeGenModule::EmitMainVoidAlias() {
7108   // In order to transition away from "__original_main" gracefully, emit an
7109   // alias for "main" in the no-argument case so that libc can detect when
7110   // new-style no-argument main is in used.
7111   if (llvm::Function *F = getModule().getFunction("main")) {
7112     if (!F->isDeclaration() && F->arg_size() == 0 && !F->isVarArg() &&
7113         F->getReturnType()->isIntegerTy(Context.getTargetInfo().getIntWidth())) {
7114       auto *GA = llvm::GlobalAlias::create("__main_void", F);
7115       GA->setVisibility(llvm::GlobalValue::HiddenVisibility);
7116     }
7117   }
7118 }
7119 
7120 /// Turns the given pointer into a constant.
7121 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context,
7122                                           const void *Ptr) {
7123   uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr);
7124   llvm::Type *i64 = llvm::Type::getInt64Ty(Context);
7125   return llvm::ConstantInt::get(i64, PtrInt);
7126 }
7127 
7128 static void EmitGlobalDeclMetadata(CodeGenModule &CGM,
7129                                    llvm::NamedMDNode *&GlobalMetadata,
7130                                    GlobalDecl D,
7131                                    llvm::GlobalValue *Addr) {
7132   if (!GlobalMetadata)
7133     GlobalMetadata =
7134       CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs");
7135 
7136   // TODO: should we report variant information for ctors/dtors?
7137   llvm::Metadata *Ops[] = {llvm::ConstantAsMetadata::get(Addr),
7138                            llvm::ConstantAsMetadata::get(GetPointerConstant(
7139                                CGM.getLLVMContext(), D.getDecl()))};
7140   GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
7141 }
7142 
7143 bool CodeGenModule::CheckAndReplaceExternCIFuncs(llvm::GlobalValue *Elem,
7144                                                  llvm::GlobalValue *CppFunc) {
7145   // Store the list of ifuncs we need to replace uses in.
7146   llvm::SmallVector<llvm::GlobalIFunc *> IFuncs;
7147   // List of ConstantExprs that we should be able to delete when we're done
7148   // here.
7149   llvm::SmallVector<llvm::ConstantExpr *> CEs;
7150 
7151   // It isn't valid to replace the extern-C ifuncs if all we find is itself!
7152   if (Elem == CppFunc)
7153     return false;
7154 
7155   // First make sure that all users of this are ifuncs (or ifuncs via a
7156   // bitcast), and collect the list of ifuncs and CEs so we can work on them
7157   // later.
7158   for (llvm::User *User : Elem->users()) {
7159     // Users can either be a bitcast ConstExpr that is used by the ifuncs, OR an
7160     // ifunc directly. In any other case, just give up, as we don't know what we
7161     // could break by changing those.
7162     if (auto *ConstExpr = dyn_cast<llvm::ConstantExpr>(User)) {
7163       if (ConstExpr->getOpcode() != llvm::Instruction::BitCast)
7164         return false;
7165 
7166       for (llvm::User *CEUser : ConstExpr->users()) {
7167         if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(CEUser)) {
7168           IFuncs.push_back(IFunc);
7169         } else {
7170           return false;
7171         }
7172       }
7173       CEs.push_back(ConstExpr);
7174     } else if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(User)) {
7175       IFuncs.push_back(IFunc);
7176     } else {
7177       // This user is one we don't know how to handle, so fail redirection. This
7178       // will result in an ifunc retaining a resolver name that will ultimately
7179       // fail to be resolved to a defined function.
7180       return false;
7181     }
7182   }
7183 
7184   // Now we know this is a valid case where we can do this alias replacement, we
7185   // need to remove all of the references to Elem (and the bitcasts!) so we can
7186   // delete it.
7187   for (llvm::GlobalIFunc *IFunc : IFuncs)
7188     IFunc->setResolver(nullptr);
7189   for (llvm::ConstantExpr *ConstExpr : CEs)
7190     ConstExpr->destroyConstant();
7191 
7192   // We should now be out of uses for the 'old' version of this function, so we
7193   // can erase it as well.
7194   Elem->eraseFromParent();
7195 
7196   for (llvm::GlobalIFunc *IFunc : IFuncs) {
7197     // The type of the resolver is always just a function-type that returns the
7198     // type of the IFunc, so create that here. If the type of the actual
7199     // resolver doesn't match, it just gets bitcast to the right thing.
7200     auto *ResolverTy =
7201         llvm::FunctionType::get(IFunc->getType(), /*isVarArg*/ false);
7202     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
7203         CppFunc->getName(), ResolverTy, {}, /*ForVTable*/ false);
7204     IFunc->setResolver(Resolver);
7205   }
7206   return true;
7207 }
7208 
7209 /// For each function which is declared within an extern "C" region and marked
7210 /// as 'used', but has internal linkage, create an alias from the unmangled
7211 /// name to the mangled name if possible. People expect to be able to refer
7212 /// to such functions with an unmangled name from inline assembly within the
7213 /// same translation unit.
7214 void CodeGenModule::EmitStaticExternCAliases() {
7215   if (!getTargetCodeGenInfo().shouldEmitStaticExternCAliases())
7216     return;
7217   for (auto &I : StaticExternCValues) {
7218     const IdentifierInfo *Name = I.first;
7219     llvm::GlobalValue *Val = I.second;
7220 
7221     // If Val is null, that implies there were multiple declarations that each
7222     // had a claim to the unmangled name. In this case, generation of the alias
7223     // is suppressed. See CodeGenModule::MaybeHandleStaticInExternC.
7224     if (!Val)
7225       break;
7226 
7227     llvm::GlobalValue *ExistingElem =
7228         getModule().getNamedValue(Name->getName());
7229 
7230     // If there is either not something already by this name, or we were able to
7231     // replace all uses from IFuncs, create the alias.
7232     if (!ExistingElem || CheckAndReplaceExternCIFuncs(ExistingElem, Val))
7233       addCompilerUsedGlobal(llvm::GlobalAlias::create(Name->getName(), Val));
7234   }
7235 }
7236 
7237 bool CodeGenModule::lookupRepresentativeDecl(StringRef MangledName,
7238                                              GlobalDecl &Result) const {
7239   auto Res = Manglings.find(MangledName);
7240   if (Res == Manglings.end())
7241     return false;
7242   Result = Res->getValue();
7243   return true;
7244 }
7245 
7246 /// Emits metadata nodes associating all the global values in the
7247 /// current module with the Decls they came from.  This is useful for
7248 /// projects using IR gen as a subroutine.
7249 ///
7250 /// Since there's currently no way to associate an MDNode directly
7251 /// with an llvm::GlobalValue, we create a global named metadata
7252 /// with the name 'clang.global.decl.ptrs'.
7253 void CodeGenModule::EmitDeclMetadata() {
7254   llvm::NamedMDNode *GlobalMetadata = nullptr;
7255 
7256   for (auto &I : MangledDeclNames) {
7257     llvm::GlobalValue *Addr = getModule().getNamedValue(I.second);
7258     // Some mangled names don't necessarily have an associated GlobalValue
7259     // in this module, e.g. if we mangled it for DebugInfo.
7260     if (Addr)
7261       EmitGlobalDeclMetadata(*this, GlobalMetadata, I.first, Addr);
7262   }
7263 }
7264 
7265 /// Emits metadata nodes for all the local variables in the current
7266 /// function.
7267 void CodeGenFunction::EmitDeclMetadata() {
7268   if (LocalDeclMap.empty()) return;
7269 
7270   llvm::LLVMContext &Context = getLLVMContext();
7271 
7272   // Find the unique metadata ID for this name.
7273   unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr");
7274 
7275   llvm::NamedMDNode *GlobalMetadata = nullptr;
7276 
7277   for (auto &I : LocalDeclMap) {
7278     const Decl *D = I.first;
7279     llvm::Value *Addr = I.second.emitRawPointer(*this);
7280     if (auto *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) {
7281       llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D);
7282       Alloca->setMetadata(
7283           DeclPtrKind, llvm::MDNode::get(
7284                            Context, llvm::ValueAsMetadata::getConstant(DAddr)));
7285     } else if (auto *GV = dyn_cast<llvm::GlobalValue>(Addr)) {
7286       GlobalDecl GD = GlobalDecl(cast<VarDecl>(D));
7287       EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV);
7288     }
7289   }
7290 }
7291 
7292 void CodeGenModule::EmitVersionIdentMetadata() {
7293   llvm::NamedMDNode *IdentMetadata =
7294     TheModule.getOrInsertNamedMetadata("llvm.ident");
7295   std::string Version = getClangFullVersion();
7296   llvm::LLVMContext &Ctx = TheModule.getContext();
7297 
7298   llvm::Metadata *IdentNode[] = {llvm::MDString::get(Ctx, Version)};
7299   IdentMetadata->addOperand(llvm::MDNode::get(Ctx, IdentNode));
7300 }
7301 
7302 void CodeGenModule::EmitCommandLineMetadata() {
7303   llvm::NamedMDNode *CommandLineMetadata =
7304     TheModule.getOrInsertNamedMetadata("llvm.commandline");
7305   std::string CommandLine = getCodeGenOpts().RecordCommandLine;
7306   llvm::LLVMContext &Ctx = TheModule.getContext();
7307 
7308   llvm::Metadata *CommandLineNode[] = {llvm::MDString::get(Ctx, CommandLine)};
7309   CommandLineMetadata->addOperand(llvm::MDNode::get(Ctx, CommandLineNode));
7310 }
7311 
7312 void CodeGenModule::EmitCoverageFile() {
7313   llvm::NamedMDNode *CUNode = TheModule.getNamedMetadata("llvm.dbg.cu");
7314   if (!CUNode)
7315     return;
7316 
7317   llvm::NamedMDNode *GCov = TheModule.getOrInsertNamedMetadata("llvm.gcov");
7318   llvm::LLVMContext &Ctx = TheModule.getContext();
7319   auto *CoverageDataFile =
7320       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageDataFile);
7321   auto *CoverageNotesFile =
7322       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageNotesFile);
7323   for (int i = 0, e = CUNode->getNumOperands(); i != e; ++i) {
7324     llvm::MDNode *CU = CUNode->getOperand(i);
7325     llvm::Metadata *Elts[] = {CoverageNotesFile, CoverageDataFile, CU};
7326     GCov->addOperand(llvm::MDNode::get(Ctx, Elts));
7327   }
7328 }
7329 
7330 llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
7331                                                        bool ForEH) {
7332   // Return a bogus pointer if RTTI is disabled, unless it's for EH.
7333   // FIXME: should we even be calling this method if RTTI is disabled
7334   // and it's not for EH?
7335   if (!shouldEmitRTTI(ForEH))
7336     return llvm::Constant::getNullValue(GlobalsInt8PtrTy);
7337 
7338   if (ForEH && Ty->isObjCObjectPointerType() &&
7339       LangOpts.ObjCRuntime.isGNUFamily())
7340     return ObjCRuntime->GetEHType(Ty);
7341 
7342   return getCXXABI().getAddrOfRTTIDescriptor(Ty);
7343 }
7344 
7345 void CodeGenModule::EmitOMPThreadPrivateDecl(const OMPThreadPrivateDecl *D) {
7346   // Do not emit threadprivates in simd-only mode.
7347   if (LangOpts.OpenMP && LangOpts.OpenMPSimd)
7348     return;
7349   for (auto RefExpr : D->varlists()) {
7350     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(RefExpr)->getDecl());
7351     bool PerformInit =
7352         VD->getAnyInitializer() &&
7353         !VD->getAnyInitializer()->isConstantInitializer(getContext(),
7354                                                         /*ForRef=*/false);
7355 
7356     Address Addr(GetAddrOfGlobalVar(VD),
7357                  getTypes().ConvertTypeForMem(VD->getType()),
7358                  getContext().getDeclAlign(VD));
7359     if (auto InitFunction = getOpenMPRuntime().emitThreadPrivateVarDefinition(
7360             VD, Addr, RefExpr->getBeginLoc(), PerformInit))
7361       CXXGlobalInits.push_back(InitFunction);
7362   }
7363 }
7364 
7365 llvm::Metadata *
7366 CodeGenModule::CreateMetadataIdentifierImpl(QualType T, MetadataTypeMap &Map,
7367                                             StringRef Suffix) {
7368   if (auto *FnType = T->getAs<FunctionProtoType>())
7369     T = getContext().getFunctionType(
7370         FnType->getReturnType(), FnType->getParamTypes(),
7371         FnType->getExtProtoInfo().withExceptionSpec(EST_None));
7372 
7373   llvm::Metadata *&InternalId = Map[T.getCanonicalType()];
7374   if (InternalId)
7375     return InternalId;
7376 
7377   if (isExternallyVisible(T->getLinkage())) {
7378     std::string OutName;
7379     llvm::raw_string_ostream Out(OutName);
7380     getCXXABI().getMangleContext().mangleCanonicalTypeName(
7381         T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
7382 
7383     if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
7384       Out << ".normalized";
7385 
7386     Out << Suffix;
7387 
7388     InternalId = llvm::MDString::get(getLLVMContext(), Out.str());
7389   } else {
7390     InternalId = llvm::MDNode::getDistinct(getLLVMContext(),
7391                                            llvm::ArrayRef<llvm::Metadata *>());
7392   }
7393 
7394   return InternalId;
7395 }
7396 
7397 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierForType(QualType T) {
7398   return CreateMetadataIdentifierImpl(T, MetadataIdMap, "");
7399 }
7400 
7401 llvm::Metadata *
7402 CodeGenModule::CreateMetadataIdentifierForVirtualMemPtrType(QualType T) {
7403   return CreateMetadataIdentifierImpl(T, VirtualMetadataIdMap, ".virtual");
7404 }
7405 
7406 // Generalize pointer types to a void pointer with the qualifiers of the
7407 // originally pointed-to type, e.g. 'const char *' and 'char * const *'
7408 // generalize to 'const void *' while 'char *' and 'const char **' generalize to
7409 // 'void *'.
7410 static QualType GeneralizeType(ASTContext &Ctx, QualType Ty) {
7411   if (!Ty->isPointerType())
7412     return Ty;
7413 
7414   return Ctx.getPointerType(
7415       QualType(Ctx.VoidTy).withCVRQualifiers(
7416           Ty->getPointeeType().getCVRQualifiers()));
7417 }
7418 
7419 // Apply type generalization to a FunctionType's return and argument types
7420 static QualType GeneralizeFunctionType(ASTContext &Ctx, QualType Ty) {
7421   if (auto *FnType = Ty->getAs<FunctionProtoType>()) {
7422     SmallVector<QualType, 8> GeneralizedParams;
7423     for (auto &Param : FnType->param_types())
7424       GeneralizedParams.push_back(GeneralizeType(Ctx, Param));
7425 
7426     return Ctx.getFunctionType(
7427         GeneralizeType(Ctx, FnType->getReturnType()),
7428         GeneralizedParams, FnType->getExtProtoInfo());
7429   }
7430 
7431   if (auto *FnType = Ty->getAs<FunctionNoProtoType>())
7432     return Ctx.getFunctionNoProtoType(
7433         GeneralizeType(Ctx, FnType->getReturnType()));
7434 
7435   llvm_unreachable("Encountered unknown FunctionType");
7436 }
7437 
7438 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierGeneralized(QualType T) {
7439   return CreateMetadataIdentifierImpl(GeneralizeFunctionType(getContext(), T),
7440                                       GeneralizedMetadataIdMap, ".generalized");
7441 }
7442 
7443 /// Returns whether this module needs the "all-vtables" type identifier.
7444 bool CodeGenModule::NeedAllVtablesTypeId() const {
7445   // Returns true if at least one of vtable-based CFI checkers is enabled and
7446   // is not in the trapping mode.
7447   return ((LangOpts.Sanitize.has(SanitizerKind::CFIVCall) &&
7448            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIVCall)) ||
7449           (LangOpts.Sanitize.has(SanitizerKind::CFINVCall) &&
7450            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFINVCall)) ||
7451           (LangOpts.Sanitize.has(SanitizerKind::CFIDerivedCast) &&
7452            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIDerivedCast)) ||
7453           (LangOpts.Sanitize.has(SanitizerKind::CFIUnrelatedCast) &&
7454            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIUnrelatedCast)));
7455 }
7456 
7457 void CodeGenModule::AddVTableTypeMetadata(llvm::GlobalVariable *VTable,
7458                                           CharUnits Offset,
7459                                           const CXXRecordDecl *RD) {
7460   llvm::Metadata *MD =
7461       CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
7462   VTable->addTypeMetadata(Offset.getQuantity(), MD);
7463 
7464   if (CodeGenOpts.SanitizeCfiCrossDso)
7465     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
7466       VTable->addTypeMetadata(Offset.getQuantity(),
7467                               llvm::ConstantAsMetadata::get(CrossDsoTypeId));
7468 
7469   if (NeedAllVtablesTypeId()) {
7470     llvm::Metadata *MD = llvm::MDString::get(getLLVMContext(), "all-vtables");
7471     VTable->addTypeMetadata(Offset.getQuantity(), MD);
7472   }
7473 }
7474 
7475 llvm::SanitizerStatReport &CodeGenModule::getSanStats() {
7476   if (!SanStats)
7477     SanStats = std::make_unique<llvm::SanitizerStatReport>(&getModule());
7478 
7479   return *SanStats;
7480 }
7481 
7482 llvm::Value *
7483 CodeGenModule::createOpenCLIntToSamplerConversion(const Expr *E,
7484                                                   CodeGenFunction &CGF) {
7485   llvm::Constant *C = ConstantEmitter(CGF).emitAbstract(E, E->getType());
7486   auto *SamplerT = getOpenCLRuntime().getSamplerType(E->getType().getTypePtr());
7487   auto *FTy = llvm::FunctionType::get(SamplerT, {C->getType()}, false);
7488   auto *Call = CGF.EmitRuntimeCall(
7489       CreateRuntimeFunction(FTy, "__translate_sampler_initializer"), {C});
7490   return Call;
7491 }
7492 
7493 CharUnits CodeGenModule::getNaturalPointeeTypeAlignment(
7494     QualType T, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) {
7495   return getNaturalTypeAlignment(T->getPointeeType(), BaseInfo, TBAAInfo,
7496                                  /* forPointeeType= */ true);
7497 }
7498 
7499 CharUnits CodeGenModule::getNaturalTypeAlignment(QualType T,
7500                                                  LValueBaseInfo *BaseInfo,
7501                                                  TBAAAccessInfo *TBAAInfo,
7502                                                  bool forPointeeType) {
7503   if (TBAAInfo)
7504     *TBAAInfo = getTBAAAccessInfo(T);
7505 
7506   // FIXME: This duplicates logic in ASTContext::getTypeAlignIfKnown. But
7507   // that doesn't return the information we need to compute BaseInfo.
7508 
7509   // Honor alignment typedef attributes even on incomplete types.
7510   // We also honor them straight for C++ class types, even as pointees;
7511   // there's an expressivity gap here.
7512   if (auto TT = T->getAs<TypedefType>()) {
7513     if (auto Align = TT->getDecl()->getMaxAlignment()) {
7514       if (BaseInfo)
7515         *BaseInfo = LValueBaseInfo(AlignmentSource::AttributedType);
7516       return getContext().toCharUnitsFromBits(Align);
7517     }
7518   }
7519 
7520   bool AlignForArray = T->isArrayType();
7521 
7522   // Analyze the base element type, so we don't get confused by incomplete
7523   // array types.
7524   T = getContext().getBaseElementType(T);
7525 
7526   if (T->isIncompleteType()) {
7527     // We could try to replicate the logic from
7528     // ASTContext::getTypeAlignIfKnown, but nothing uses the alignment if the
7529     // type is incomplete, so it's impossible to test. We could try to reuse
7530     // getTypeAlignIfKnown, but that doesn't return the information we need
7531     // to set BaseInfo.  So just ignore the possibility that the alignment is
7532     // greater than one.
7533     if (BaseInfo)
7534       *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
7535     return CharUnits::One();
7536   }
7537 
7538   if (BaseInfo)
7539     *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
7540 
7541   CharUnits Alignment;
7542   const CXXRecordDecl *RD;
7543   if (T.getQualifiers().hasUnaligned()) {
7544     Alignment = CharUnits::One();
7545   } else if (forPointeeType && !AlignForArray &&
7546              (RD = T->getAsCXXRecordDecl())) {
7547     // For C++ class pointees, we don't know whether we're pointing at a
7548     // base or a complete object, so we generally need to use the
7549     // non-virtual alignment.
7550     Alignment = getClassPointerAlignment(RD);
7551   } else {
7552     Alignment = getContext().getTypeAlignInChars(T);
7553   }
7554 
7555   // Cap to the global maximum type alignment unless the alignment
7556   // was somehow explicit on the type.
7557   if (unsigned MaxAlign = getLangOpts().MaxTypeAlign) {
7558     if (Alignment.getQuantity() > MaxAlign &&
7559         !getContext().isAlignmentRequired(T))
7560       Alignment = CharUnits::fromQuantity(MaxAlign);
7561   }
7562   return Alignment;
7563 }
7564 
7565 bool CodeGenModule::stopAutoInit() {
7566   unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter;
7567   if (StopAfter) {
7568     // This number is positive only when -ftrivial-auto-var-init-stop-after=* is
7569     // used
7570     if (NumAutoVarInit >= StopAfter) {
7571       return true;
7572     }
7573     if (!NumAutoVarInit) {
7574       unsigned DiagID = getDiags().getCustomDiagID(
7575           DiagnosticsEngine::Warning,
7576           "-ftrivial-auto-var-init-stop-after=%0 has been enabled to limit the "
7577           "number of times ftrivial-auto-var-init=%1 gets applied.");
7578       getDiags().Report(DiagID)
7579           << StopAfter
7580           << (getContext().getLangOpts().getTrivialAutoVarInit() ==
7581                       LangOptions::TrivialAutoVarInitKind::Zero
7582                   ? "zero"
7583                   : "pattern");
7584     }
7585     ++NumAutoVarInit;
7586   }
7587   return false;
7588 }
7589 
7590 void CodeGenModule::printPostfixForExternalizedDecl(llvm::raw_ostream &OS,
7591                                                     const Decl *D) const {
7592   // ptxas does not allow '.' in symbol names. On the other hand, HIP prefers
7593   // postfix beginning with '.' since the symbol name can be demangled.
7594   if (LangOpts.HIP)
7595     OS << (isa<VarDecl>(D) ? ".static." : ".intern.");
7596   else
7597     OS << (isa<VarDecl>(D) ? "__static__" : "__intern__");
7598 
7599   // If the CUID is not specified we try to generate a unique postfix.
7600   if (getLangOpts().CUID.empty()) {
7601     SourceManager &SM = getContext().getSourceManager();
7602     PresumedLoc PLoc = SM.getPresumedLoc(D->getLocation());
7603     assert(PLoc.isValid() && "Source location is expected to be valid.");
7604 
7605     // Get the hash of the user defined macros.
7606     llvm::MD5 Hash;
7607     llvm::MD5::MD5Result Result;
7608     for (const auto &Arg : PreprocessorOpts.Macros)
7609       Hash.update(Arg.first);
7610     Hash.final(Result);
7611 
7612     // Get the UniqueID for the file containing the decl.
7613     llvm::sys::fs::UniqueID ID;
7614     if (llvm::sys::fs::getUniqueID(PLoc.getFilename(), ID)) {
7615       PLoc = SM.getPresumedLoc(D->getLocation(), /*UseLineDirectives=*/false);
7616       assert(PLoc.isValid() && "Source location is expected to be valid.");
7617       if (auto EC = llvm::sys::fs::getUniqueID(PLoc.getFilename(), ID))
7618         SM.getDiagnostics().Report(diag::err_cannot_open_file)
7619             << PLoc.getFilename() << EC.message();
7620     }
7621     OS << llvm::format("%x", ID.getFile()) << llvm::format("%x", ID.getDevice())
7622        << "_" << llvm::utohexstr(Result.low(), /*LowerCase=*/true, /*Width=*/8);
7623   } else {
7624     OS << getContext().getCUIDHash();
7625   }
7626 }
7627 
7628 void CodeGenModule::moveLazyEmissionStates(CodeGenModule *NewBuilder) {
7629   assert(DeferredDeclsToEmit.empty() &&
7630          "Should have emitted all decls deferred to emit.");
7631   assert(NewBuilder->DeferredDecls.empty() &&
7632          "Newly created module should not have deferred decls");
7633   NewBuilder->DeferredDecls = std::move(DeferredDecls);
7634   assert(EmittedDeferredDecls.empty() &&
7635          "Still have (unmerged) EmittedDeferredDecls deferred decls");
7636 
7637   assert(NewBuilder->DeferredVTables.empty() &&
7638          "Newly created module should not have deferred vtables");
7639   NewBuilder->DeferredVTables = std::move(DeferredVTables);
7640 
7641   assert(NewBuilder->MangledDeclNames.empty() &&
7642          "Newly created module should not have mangled decl names");
7643   assert(NewBuilder->Manglings.empty() &&
7644          "Newly created module should not have manglings");
7645   NewBuilder->Manglings = std::move(Manglings);
7646 
7647   NewBuilder->WeakRefReferences = std::move(WeakRefReferences);
7648 
7649   NewBuilder->TBAA = std::move(TBAA);
7650 
7651   NewBuilder->ABI->MangleCtx = std::move(ABI->MangleCtx);
7652 }
7653