xref: /llvm-project/clang/lib/CodeGen/CodeGenModule.cpp (revision c6d70722b49db01914d5f64cc86ea5ed609ad9fd)
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/DeclCXX.h"
34 #include "clang/AST/DeclObjC.h"
35 #include "clang/AST/DeclTemplate.h"
36 #include "clang/AST/Mangle.h"
37 #include "clang/AST/RecursiveASTVisitor.h"
38 #include "clang/AST/StmtVisitor.h"
39 #include "clang/Basic/Builtins.h"
40 #include "clang/Basic/CharInfo.h"
41 #include "clang/Basic/CodeGenOptions.h"
42 #include "clang/Basic/Diagnostic.h"
43 #include "clang/Basic/FileManager.h"
44 #include "clang/Basic/Module.h"
45 #include "clang/Basic/SourceManager.h"
46 #include "clang/Basic/TargetInfo.h"
47 #include "clang/Basic/Version.h"
48 #include "clang/CodeGen/BackendUtil.h"
49 #include "clang/CodeGen/ConstantInitBuilder.h"
50 #include "clang/Frontend/FrontendDiagnostic.h"
51 #include "llvm/ADT/STLExtras.h"
52 #include "llvm/ADT/StringExtras.h"
53 #include "llvm/ADT/StringSwitch.h"
54 #include "llvm/Analysis/TargetLibraryInfo.h"
55 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
56 #include "llvm/IR/AttributeMask.h"
57 #include "llvm/IR/CallingConv.h"
58 #include "llvm/IR/DataLayout.h"
59 #include "llvm/IR/Intrinsics.h"
60 #include "llvm/IR/LLVMContext.h"
61 #include "llvm/IR/Module.h"
62 #include "llvm/IR/ProfileSummary.h"
63 #include "llvm/ProfileData/InstrProfReader.h"
64 #include "llvm/ProfileData/SampleProf.h"
65 #include "llvm/Support/CRC.h"
66 #include "llvm/Support/CodeGen.h"
67 #include "llvm/Support/CommandLine.h"
68 #include "llvm/Support/ConvertUTF.h"
69 #include "llvm/Support/ErrorHandling.h"
70 #include "llvm/Support/TimeProfiler.h"
71 #include "llvm/Support/xxhash.h"
72 #include "llvm/TargetParser/Triple.h"
73 #include "llvm/TargetParser/X86TargetParser.h"
74 #include <optional>
75 
76 using namespace clang;
77 using namespace CodeGen;
78 
79 static llvm::cl::opt<bool> LimitedCoverage(
80     "limited-coverage-experimental", llvm::cl::Hidden,
81     llvm::cl::desc("Emit limited coverage mapping information (experimental)"));
82 
83 static const char AnnotationSection[] = "llvm.metadata";
84 
85 static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
86   switch (CGM.getContext().getCXXABIKind()) {
87   case TargetCXXABI::AppleARM64:
88   case TargetCXXABI::Fuchsia:
89   case TargetCXXABI::GenericAArch64:
90   case TargetCXXABI::GenericARM:
91   case TargetCXXABI::iOS:
92   case TargetCXXABI::WatchOS:
93   case TargetCXXABI::GenericMIPS:
94   case TargetCXXABI::GenericItanium:
95   case TargetCXXABI::WebAssembly:
96   case TargetCXXABI::XL:
97     return CreateItaniumCXXABI(CGM);
98   case TargetCXXABI::Microsoft:
99     return CreateMicrosoftCXXABI(CGM);
100   }
101 
102   llvm_unreachable("invalid C++ ABI kind");
103 }
104 
105 static std::unique_ptr<TargetCodeGenInfo>
106 createTargetCodeGenInfo(CodeGenModule &CGM) {
107   const TargetInfo &Target = CGM.getTarget();
108   const llvm::Triple &Triple = Target.getTriple();
109   const CodeGenOptions &CodeGenOpts = CGM.getCodeGenOpts();
110 
111   switch (Triple.getArch()) {
112   default:
113     return createDefaultTargetCodeGenInfo(CGM);
114 
115   case llvm::Triple::le32:
116     return createPNaClTargetCodeGenInfo(CGM);
117   case llvm::Triple::m68k:
118     return createM68kTargetCodeGenInfo(CGM);
119   case llvm::Triple::mips:
120   case llvm::Triple::mipsel:
121     if (Triple.getOS() == llvm::Triple::NaCl)
122       return createPNaClTargetCodeGenInfo(CGM);
123     return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/true);
124 
125   case llvm::Triple::mips64:
126   case llvm::Triple::mips64el:
127     return createMIPSTargetCodeGenInfo(CGM, /*IsOS32=*/false);
128 
129   case llvm::Triple::avr: {
130     // For passing parameters, R8~R25 are used on avr, and R18~R25 are used
131     // on avrtiny. For passing return value, R18~R25 are used on avr, and
132     // R22~R25 are used on avrtiny.
133     unsigned NPR = Target.getABI() == "avrtiny" ? 6 : 18;
134     unsigned NRR = Target.getABI() == "avrtiny" ? 4 : 8;
135     return createAVRTargetCodeGenInfo(CGM, NPR, NRR);
136   }
137 
138   case llvm::Triple::aarch64:
139   case llvm::Triple::aarch64_32:
140   case llvm::Triple::aarch64_be: {
141     AArch64ABIKind Kind = AArch64ABIKind::AAPCS;
142     if (Target.getABI() == "darwinpcs")
143       Kind = AArch64ABIKind::DarwinPCS;
144     else if (Triple.isOSWindows())
145       return createWindowsAArch64TargetCodeGenInfo(CGM, AArch64ABIKind::Win64);
146 
147     return createAArch64TargetCodeGenInfo(CGM, Kind);
148   }
149 
150   case llvm::Triple::wasm32:
151   case llvm::Triple::wasm64: {
152     WebAssemblyABIKind Kind = WebAssemblyABIKind::MVP;
153     if (Target.getABI() == "experimental-mv")
154       Kind = WebAssemblyABIKind::ExperimentalMV;
155     return createWebAssemblyTargetCodeGenInfo(CGM, Kind);
156   }
157 
158   case llvm::Triple::arm:
159   case llvm::Triple::armeb:
160   case llvm::Triple::thumb:
161   case llvm::Triple::thumbeb: {
162     if (Triple.getOS() == llvm::Triple::Win32)
163       return createWindowsARMTargetCodeGenInfo(CGM, ARMABIKind::AAPCS_VFP);
164 
165     ARMABIKind Kind = ARMABIKind::AAPCS;
166     StringRef ABIStr = Target.getABI();
167     if (ABIStr == "apcs-gnu")
168       Kind = ARMABIKind::APCS;
169     else if (ABIStr == "aapcs16")
170       Kind = ARMABIKind::AAPCS16_VFP;
171     else if (CodeGenOpts.FloatABI == "hard" ||
172              (CodeGenOpts.FloatABI != "soft" &&
173               (Triple.getEnvironment() == llvm::Triple::GNUEABIHF ||
174                Triple.getEnvironment() == llvm::Triple::MuslEABIHF ||
175                Triple.getEnvironment() == llvm::Triple::EABIHF)))
176       Kind = ARMABIKind::AAPCS_VFP;
177 
178     return createARMTargetCodeGenInfo(CGM, Kind);
179   }
180 
181   case llvm::Triple::ppc: {
182     if (Triple.isOSAIX())
183       return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/false);
184 
185     bool IsSoftFloat =
186         CodeGenOpts.FloatABI == "soft" || Target.hasFeature("spe");
187     return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
188   }
189   case llvm::Triple::ppcle: {
190     bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
191     return createPPC32TargetCodeGenInfo(CGM, IsSoftFloat);
192   }
193   case llvm::Triple::ppc64:
194     if (Triple.isOSAIX())
195       return createAIXTargetCodeGenInfo(CGM, /*Is64Bit=*/true);
196 
197     if (Triple.isOSBinFormatELF()) {
198       PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv1;
199       if (Target.getABI() == "elfv2")
200         Kind = PPC64_SVR4_ABIKind::ELFv2;
201       bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
202 
203       return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
204     }
205     return createPPC64TargetCodeGenInfo(CGM);
206   case llvm::Triple::ppc64le: {
207     assert(Triple.isOSBinFormatELF() && "PPC64 LE non-ELF not supported!");
208     PPC64_SVR4_ABIKind Kind = PPC64_SVR4_ABIKind::ELFv2;
209     if (Target.getABI() == "elfv1")
210       Kind = PPC64_SVR4_ABIKind::ELFv1;
211     bool IsSoftFloat = CodeGenOpts.FloatABI == "soft";
212 
213     return createPPC64_SVR4_TargetCodeGenInfo(CGM, Kind, IsSoftFloat);
214   }
215 
216   case llvm::Triple::nvptx:
217   case llvm::Triple::nvptx64:
218     return createNVPTXTargetCodeGenInfo(CGM);
219 
220   case llvm::Triple::msp430:
221     return createMSP430TargetCodeGenInfo(CGM);
222 
223   case llvm::Triple::riscv32:
224   case llvm::Triple::riscv64: {
225     StringRef ABIStr = Target.getABI();
226     unsigned XLen = Target.getPointerWidth(LangAS::Default);
227     unsigned ABIFLen = 0;
228     if (ABIStr.endswith("f"))
229       ABIFLen = 32;
230     else if (ABIStr.endswith("d"))
231       ABIFLen = 64;
232     return createRISCVTargetCodeGenInfo(CGM, XLen, ABIFLen);
233   }
234 
235   case llvm::Triple::systemz: {
236     bool SoftFloat = CodeGenOpts.FloatABI == "soft";
237     bool HasVector = !SoftFloat && Target.getABI() == "vector";
238     return createSystemZTargetCodeGenInfo(CGM, HasVector, SoftFloat);
239   }
240 
241   case llvm::Triple::tce:
242   case llvm::Triple::tcele:
243     return createTCETargetCodeGenInfo(CGM);
244 
245   case llvm::Triple::x86: {
246     bool IsDarwinVectorABI = Triple.isOSDarwin();
247     bool IsWin32FloatStructABI = Triple.isOSWindows() && !Triple.isOSCygMing();
248 
249     if (Triple.getOS() == llvm::Triple::Win32) {
250       return createWinX86_32TargetCodeGenInfo(
251           CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
252           CodeGenOpts.NumRegisterParameters);
253     }
254     return createX86_32TargetCodeGenInfo(
255         CGM, IsDarwinVectorABI, IsWin32FloatStructABI,
256         CodeGenOpts.NumRegisterParameters, CodeGenOpts.FloatABI == "soft");
257   }
258 
259   case llvm::Triple::x86_64: {
260     StringRef ABI = Target.getABI();
261     X86AVXABILevel AVXLevel = (ABI == "avx512" ? X86AVXABILevel::AVX512
262                                : ABI == "avx"  ? X86AVXABILevel::AVX
263                                                : X86AVXABILevel::None);
264 
265     switch (Triple.getOS()) {
266     case llvm::Triple::Win32:
267       return createWinX86_64TargetCodeGenInfo(CGM, AVXLevel);
268     default:
269       return createX86_64TargetCodeGenInfo(CGM, AVXLevel);
270     }
271   }
272   case llvm::Triple::hexagon:
273     return createHexagonTargetCodeGenInfo(CGM);
274   case llvm::Triple::lanai:
275     return createLanaiTargetCodeGenInfo(CGM);
276   case llvm::Triple::r600:
277     return createAMDGPUTargetCodeGenInfo(CGM);
278   case llvm::Triple::amdgcn:
279     return createAMDGPUTargetCodeGenInfo(CGM);
280   case llvm::Triple::sparc:
281     return createSparcV8TargetCodeGenInfo(CGM);
282   case llvm::Triple::sparcv9:
283     return createSparcV9TargetCodeGenInfo(CGM);
284   case llvm::Triple::xcore:
285     return createXCoreTargetCodeGenInfo(CGM);
286   case llvm::Triple::arc:
287     return createARCTargetCodeGenInfo(CGM);
288   case llvm::Triple::spir:
289   case llvm::Triple::spir64:
290     return createCommonSPIRTargetCodeGenInfo(CGM);
291   case llvm::Triple::spirv32:
292   case llvm::Triple::spirv64:
293     return createSPIRVTargetCodeGenInfo(CGM);
294   case llvm::Triple::ve:
295     return createVETargetCodeGenInfo(CGM);
296   case llvm::Triple::csky: {
297     bool IsSoftFloat = !Target.hasFeature("hard-float-abi");
298     bool hasFP64 =
299         Target.hasFeature("fpuv2_df") || Target.hasFeature("fpuv3_df");
300     return createCSKYTargetCodeGenInfo(CGM, IsSoftFloat ? 0
301                                             : hasFP64   ? 64
302                                                         : 32);
303   }
304   case llvm::Triple::bpfeb:
305   case llvm::Triple::bpfel:
306     return createBPFTargetCodeGenInfo(CGM);
307   case llvm::Triple::loongarch32:
308   case llvm::Triple::loongarch64: {
309     StringRef ABIStr = Target.getABI();
310     unsigned ABIFRLen = 0;
311     if (ABIStr.endswith("f"))
312       ABIFRLen = 32;
313     else if (ABIStr.endswith("d"))
314       ABIFRLen = 64;
315     return createLoongArchTargetCodeGenInfo(
316         CGM, Target.getPointerWidth(LangAS::Default), ABIFRLen);
317   }
318   }
319 }
320 
321 const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
322   if (!TheTargetCodeGenInfo)
323     TheTargetCodeGenInfo = createTargetCodeGenInfo(*this);
324   return *TheTargetCodeGenInfo;
325 }
326 
327 CodeGenModule::CodeGenModule(ASTContext &C,
328                              IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
329                              const HeaderSearchOptions &HSO,
330                              const PreprocessorOptions &PPO,
331                              const CodeGenOptions &CGO, llvm::Module &M,
332                              DiagnosticsEngine &diags,
333                              CoverageSourceInfo *CoverageInfo)
334     : Context(C), LangOpts(C.getLangOpts()), FS(FS), HeaderSearchOpts(HSO),
335       PreprocessorOpts(PPO), CodeGenOpts(CGO), TheModule(M), Diags(diags),
336       Target(C.getTargetInfo()), ABI(createCXXABI(*this)),
337       VMContext(M.getContext()), Types(*this), VTables(*this),
338       SanitizerMD(new SanitizerMetadata(*this)) {
339 
340   // Initialize the type cache.
341   llvm::LLVMContext &LLVMContext = M.getContext();
342   VoidTy = llvm::Type::getVoidTy(LLVMContext);
343   Int8Ty = llvm::Type::getInt8Ty(LLVMContext);
344   Int16Ty = llvm::Type::getInt16Ty(LLVMContext);
345   Int32Ty = llvm::Type::getInt32Ty(LLVMContext);
346   Int64Ty = llvm::Type::getInt64Ty(LLVMContext);
347   HalfTy = llvm::Type::getHalfTy(LLVMContext);
348   BFloatTy = llvm::Type::getBFloatTy(LLVMContext);
349   FloatTy = llvm::Type::getFloatTy(LLVMContext);
350   DoubleTy = llvm::Type::getDoubleTy(LLVMContext);
351   PointerWidthInBits = C.getTargetInfo().getPointerWidth(LangAS::Default);
352   PointerAlignInBytes =
353       C.toCharUnitsFromBits(C.getTargetInfo().getPointerAlign(LangAS::Default))
354           .getQuantity();
355   SizeSizeInBytes =
356     C.toCharUnitsFromBits(C.getTargetInfo().getMaxPointerWidth()).getQuantity();
357   IntAlignInBytes =
358     C.toCharUnitsFromBits(C.getTargetInfo().getIntAlign()).getQuantity();
359   CharTy =
360     llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getCharWidth());
361   IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
362   IntPtrTy = llvm::IntegerType::get(LLVMContext,
363     C.getTargetInfo().getMaxPointerWidth());
364   Int8PtrTy = llvm::PointerType::get(LLVMContext, 0);
365   const llvm::DataLayout &DL = M.getDataLayout();
366   AllocaInt8PtrTy =
367       llvm::PointerType::get(LLVMContext, DL.getAllocaAddrSpace());
368   GlobalsInt8PtrTy =
369       llvm::PointerType::get(LLVMContext, DL.getDefaultGlobalsAddressSpace());
370   ConstGlobalsPtrTy = llvm::PointerType::get(
371       LLVMContext, C.getTargetAddressSpace(GetGlobalConstantAddressSpace()));
372   ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
373 
374   // Build C++20 Module initializers.
375   // TODO: Add Microsoft here once we know the mangling required for the
376   // initializers.
377   CXX20ModuleInits =
378       LangOpts.CPlusPlusModules && getCXXABI().getMangleContext().getKind() ==
379                                        ItaniumMangleContext::MK_Itanium;
380 
381   RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC();
382 
383   if (LangOpts.ObjC)
384     createObjCRuntime();
385   if (LangOpts.OpenCL)
386     createOpenCLRuntime();
387   if (LangOpts.OpenMP)
388     createOpenMPRuntime();
389   if (LangOpts.CUDA)
390     createCUDARuntime();
391   if (LangOpts.HLSL)
392     createHLSLRuntime();
393 
394   // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0.
395   if (LangOpts.Sanitize.has(SanitizerKind::Thread) ||
396       (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0))
397     TBAA.reset(new CodeGenTBAA(Context, TheModule, CodeGenOpts, getLangOpts(),
398                                getCXXABI().getMangleContext()));
399 
400   // If debug info or coverage generation is enabled, create the CGDebugInfo
401   // object.
402   if (CodeGenOpts.getDebugInfo() != llvm::codegenoptions::NoDebugInfo ||
403       CodeGenOpts.CoverageNotesFile.size() ||
404       CodeGenOpts.CoverageDataFile.size())
405     DebugInfo.reset(new CGDebugInfo(*this));
406 
407   Block.GlobalUniqueCount = 0;
408 
409   if (C.getLangOpts().ObjC)
410     ObjCData.reset(new ObjCEntrypoints());
411 
412   if (CodeGenOpts.hasProfileClangUse()) {
413     auto ReaderOrErr = llvm::IndexedInstrProfReader::create(
414         CodeGenOpts.ProfileInstrumentUsePath, *FS,
415         CodeGenOpts.ProfileRemappingFile);
416     // We're checking for profile read errors in CompilerInvocation, so if
417     // there was an error it should've already been caught. If it hasn't been
418     // somehow, trip an assertion.
419     assert(ReaderOrErr);
420     PGOReader = std::move(ReaderOrErr.get());
421   }
422 
423   // If coverage mapping generation is enabled, create the
424   // CoverageMappingModuleGen object.
425   if (CodeGenOpts.CoverageMapping)
426     CoverageMapping.reset(new CoverageMappingModuleGen(*this, *CoverageInfo));
427 
428   // Generate the module name hash here if needed.
429   if (CodeGenOpts.UniqueInternalLinkageNames &&
430       !getModule().getSourceFileName().empty()) {
431     std::string Path = getModule().getSourceFileName();
432     // Check if a path substitution is needed from the MacroPrefixMap.
433     for (const auto &Entry : LangOpts.MacroPrefixMap)
434       if (Path.rfind(Entry.first, 0) != std::string::npos) {
435         Path = Entry.second + Path.substr(Entry.first.size());
436         break;
437       }
438     ModuleNameHash = llvm::getUniqueInternalLinkagePostfix(Path);
439   }
440 }
441 
442 CodeGenModule::~CodeGenModule() {}
443 
444 void CodeGenModule::createObjCRuntime() {
445   // This is just isGNUFamily(), but we want to force implementors of
446   // new ABIs to decide how best to do this.
447   switch (LangOpts.ObjCRuntime.getKind()) {
448   case ObjCRuntime::GNUstep:
449   case ObjCRuntime::GCC:
450   case ObjCRuntime::ObjFW:
451     ObjCRuntime.reset(CreateGNUObjCRuntime(*this));
452     return;
453 
454   case ObjCRuntime::FragileMacOSX:
455   case ObjCRuntime::MacOSX:
456   case ObjCRuntime::iOS:
457   case ObjCRuntime::WatchOS:
458     ObjCRuntime.reset(CreateMacObjCRuntime(*this));
459     return;
460   }
461   llvm_unreachable("bad runtime kind");
462 }
463 
464 void CodeGenModule::createOpenCLRuntime() {
465   OpenCLRuntime.reset(new CGOpenCLRuntime(*this));
466 }
467 
468 void CodeGenModule::createOpenMPRuntime() {
469   // Select a specialized code generation class based on the target, if any.
470   // If it does not exist use the default implementation.
471   switch (getTriple().getArch()) {
472   case llvm::Triple::nvptx:
473   case llvm::Triple::nvptx64:
474   case llvm::Triple::amdgcn:
475     assert(getLangOpts().OpenMPIsTargetDevice &&
476            "OpenMP AMDGPU/NVPTX is only prepared to deal with device code.");
477     OpenMPRuntime.reset(new CGOpenMPRuntimeGPU(*this));
478     break;
479   default:
480     if (LangOpts.OpenMPSimd)
481       OpenMPRuntime.reset(new CGOpenMPSIMDRuntime(*this));
482     else
483       OpenMPRuntime.reset(new CGOpenMPRuntime(*this));
484     break;
485   }
486 }
487 
488 void CodeGenModule::createCUDARuntime() {
489   CUDARuntime.reset(CreateNVCUDARuntime(*this));
490 }
491 
492 void CodeGenModule::createHLSLRuntime() {
493   HLSLRuntime.reset(new CGHLSLRuntime(*this));
494 }
495 
496 void CodeGenModule::addReplacement(StringRef Name, llvm::Constant *C) {
497   Replacements[Name] = C;
498 }
499 
500 void CodeGenModule::applyReplacements() {
501   for (auto &I : Replacements) {
502     StringRef MangledName = I.first;
503     llvm::Constant *Replacement = I.second;
504     llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
505     if (!Entry)
506       continue;
507     auto *OldF = cast<llvm::Function>(Entry);
508     auto *NewF = dyn_cast<llvm::Function>(Replacement);
509     if (!NewF) {
510       if (auto *Alias = dyn_cast<llvm::GlobalAlias>(Replacement)) {
511         NewF = dyn_cast<llvm::Function>(Alias->getAliasee());
512       } else {
513         auto *CE = cast<llvm::ConstantExpr>(Replacement);
514         assert(CE->getOpcode() == llvm::Instruction::BitCast ||
515                CE->getOpcode() == llvm::Instruction::GetElementPtr);
516         NewF = dyn_cast<llvm::Function>(CE->getOperand(0));
517       }
518     }
519 
520     // Replace old with new, but keep the old order.
521     OldF->replaceAllUsesWith(Replacement);
522     if (NewF) {
523       NewF->removeFromParent();
524       OldF->getParent()->getFunctionList().insertAfter(OldF->getIterator(),
525                                                        NewF);
526     }
527     OldF->eraseFromParent();
528   }
529 }
530 
531 void CodeGenModule::addGlobalValReplacement(llvm::GlobalValue *GV, llvm::Constant *C) {
532   GlobalValReplacements.push_back(std::make_pair(GV, C));
533 }
534 
535 void CodeGenModule::applyGlobalValReplacements() {
536   for (auto &I : GlobalValReplacements) {
537     llvm::GlobalValue *GV = I.first;
538     llvm::Constant *C = I.second;
539 
540     GV->replaceAllUsesWith(C);
541     GV->eraseFromParent();
542   }
543 }
544 
545 // This is only used in aliases that we created and we know they have a
546 // linear structure.
547 static const llvm::GlobalValue *getAliasedGlobal(const llvm::GlobalValue *GV) {
548   const llvm::Constant *C;
549   if (auto *GA = dyn_cast<llvm::GlobalAlias>(GV))
550     C = GA->getAliasee();
551   else if (auto *GI = dyn_cast<llvm::GlobalIFunc>(GV))
552     C = GI->getResolver();
553   else
554     return GV;
555 
556   const auto *AliaseeGV = dyn_cast<llvm::GlobalValue>(C->stripPointerCasts());
557   if (!AliaseeGV)
558     return nullptr;
559 
560   const llvm::GlobalValue *FinalGV = AliaseeGV->getAliaseeObject();
561   if (FinalGV == GV)
562     return nullptr;
563 
564   return FinalGV;
565 }
566 
567 static bool checkAliasedGlobal(
568     const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation Location,
569     bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
570     const llvm::MapVector<GlobalDecl, StringRef> &MangledDeclNames,
571     SourceRange AliasRange) {
572   GV = getAliasedGlobal(Alias);
573   if (!GV) {
574     Diags.Report(Location, diag::err_cyclic_alias) << IsIFunc;
575     return false;
576   }
577 
578   if (GV->hasCommonLinkage()) {
579     const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
580     if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
581       Diags.Report(Location, diag::err_alias_to_common);
582       return false;
583     }
584   }
585 
586   if (GV->isDeclaration()) {
587     Diags.Report(Location, diag::err_alias_to_undefined) << IsIFunc << IsIFunc;
588     Diags.Report(Location, diag::note_alias_requires_mangled_name)
589         << IsIFunc << IsIFunc;
590     // Provide a note if the given function is not found and exists as a
591     // mangled name.
592     for (const auto &[Decl, Name] : MangledDeclNames) {
593       if (const auto *ND = dyn_cast<NamedDecl>(Decl.getDecl())) {
594         if (ND->getName() == GV->getName()) {
595           Diags.Report(Location, diag::note_alias_mangled_name_alternative)
596               << Name
597               << FixItHint::CreateReplacement(
598                      AliasRange,
599                      (Twine(IsIFunc ? "ifunc" : "alias") + "(\"" + Name + "\")")
600                          .str());
601         }
602       }
603     }
604     return false;
605   }
606 
607   if (IsIFunc) {
608     // Check resolver function type.
609     const auto *F = dyn_cast<llvm::Function>(GV);
610     if (!F) {
611       Diags.Report(Location, diag::err_alias_to_undefined)
612           << IsIFunc << IsIFunc;
613       return false;
614     }
615 
616     llvm::FunctionType *FTy = F->getFunctionType();
617     if (!FTy->getReturnType()->isPointerTy()) {
618       Diags.Report(Location, diag::err_ifunc_resolver_return);
619       return false;
620     }
621   }
622 
623   return true;
624 }
625 
626 void CodeGenModule::checkAliases() {
627   // Check if the constructed aliases are well formed. It is really unfortunate
628   // that we have to do this in CodeGen, but we only construct mangled names
629   // and aliases during codegen.
630   bool Error = false;
631   DiagnosticsEngine &Diags = getDiags();
632   for (const GlobalDecl &GD : Aliases) {
633     const auto *D = cast<ValueDecl>(GD.getDecl());
634     SourceLocation Location;
635     SourceRange Range;
636     bool IsIFunc = D->hasAttr<IFuncAttr>();
637     if (const Attr *A = D->getDefiningAttr()) {
638       Location = A->getLocation();
639       Range = A->getRange();
640     } else
641       llvm_unreachable("Not an alias or ifunc?");
642 
643     StringRef MangledName = getMangledName(GD);
644     llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
645     const llvm::GlobalValue *GV = nullptr;
646     if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
647                             MangledDeclNames, Range)) {
648       Error = true;
649       continue;
650     }
651 
652     llvm::Constant *Aliasee =
653         IsIFunc ? cast<llvm::GlobalIFunc>(Alias)->getResolver()
654                 : cast<llvm::GlobalAlias>(Alias)->getAliasee();
655 
656     llvm::GlobalValue *AliaseeGV;
657     if (auto CE = dyn_cast<llvm::ConstantExpr>(Aliasee))
658       AliaseeGV = cast<llvm::GlobalValue>(CE->getOperand(0));
659     else
660       AliaseeGV = cast<llvm::GlobalValue>(Aliasee);
661 
662     if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
663       StringRef AliasSection = SA->getName();
664       if (AliasSection != AliaseeGV->getSection())
665         Diags.Report(SA->getLocation(), diag::warn_alias_with_section)
666             << AliasSection << IsIFunc << IsIFunc;
667     }
668 
669     // We have to handle alias to weak aliases in here. LLVM itself disallows
670     // this since the object semantics would not match the IL one. For
671     // compatibility with gcc we implement it by just pointing the alias
672     // to its aliasee's aliasee. We also warn, since the user is probably
673     // expecting the link to be weak.
674     if (auto *GA = dyn_cast<llvm::GlobalAlias>(AliaseeGV)) {
675       if (GA->isInterposable()) {
676         Diags.Report(Location, diag::warn_alias_to_weak_alias)
677             << GV->getName() << GA->getName() << IsIFunc;
678         Aliasee = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
679             GA->getAliasee(), Alias->getType());
680 
681         if (IsIFunc)
682           cast<llvm::GlobalIFunc>(Alias)->setResolver(Aliasee);
683         else
684           cast<llvm::GlobalAlias>(Alias)->setAliasee(Aliasee);
685       }
686     }
687   }
688   if (!Error)
689     return;
690 
691   for (const GlobalDecl &GD : Aliases) {
692     StringRef MangledName = getMangledName(GD);
693     llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
694     Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
695     Alias->eraseFromParent();
696   }
697 }
698 
699 void CodeGenModule::clear() {
700   DeferredDeclsToEmit.clear();
701   EmittedDeferredDecls.clear();
702   DeferredAnnotations.clear();
703   if (OpenMPRuntime)
704     OpenMPRuntime->clear();
705 }
706 
707 void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
708                                        StringRef MainFile) {
709   if (!hasDiagnostics())
710     return;
711   if (VisitedInMainFile > 0 && VisitedInMainFile == MissingInMainFile) {
712     if (MainFile.empty())
713       MainFile = "<stdin>";
714     Diags.Report(diag::warn_profile_data_unprofiled) << MainFile;
715   } else {
716     if (Mismatched > 0)
717       Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Mismatched;
718 
719     if (Missing > 0)
720       Diags.Report(diag::warn_profile_data_missing) << Visited << Missing;
721   }
722 }
723 
724 static void setVisibilityFromDLLStorageClass(const clang::LangOptions &LO,
725                                              llvm::Module &M) {
726   if (!LO.VisibilityFromDLLStorageClass)
727     return;
728 
729   llvm::GlobalValue::VisibilityTypes DLLExportVisibility =
730       CodeGenModule::GetLLVMVisibility(LO.getDLLExportVisibility());
731   llvm::GlobalValue::VisibilityTypes NoDLLStorageClassVisibility =
732       CodeGenModule::GetLLVMVisibility(LO.getNoDLLStorageClassVisibility());
733   llvm::GlobalValue::VisibilityTypes ExternDeclDLLImportVisibility =
734       CodeGenModule::GetLLVMVisibility(LO.getExternDeclDLLImportVisibility());
735   llvm::GlobalValue::VisibilityTypes ExternDeclNoDLLStorageClassVisibility =
736       CodeGenModule::GetLLVMVisibility(
737           LO.getExternDeclNoDLLStorageClassVisibility());
738 
739   for (llvm::GlobalValue &GV : M.global_values()) {
740     if (GV.hasAppendingLinkage() || GV.hasLocalLinkage())
741       continue;
742 
743     // Reset DSO locality before setting the visibility. This removes
744     // any effects that visibility options and annotations may have
745     // had on the DSO locality. Setting the visibility will implicitly set
746     // appropriate globals to DSO Local; however, this will be pessimistic
747     // w.r.t. to the normal compiler IRGen.
748     GV.setDSOLocal(false);
749 
750     if (GV.isDeclarationForLinker()) {
751       GV.setVisibility(GV.getDLLStorageClass() ==
752                                llvm::GlobalValue::DLLImportStorageClass
753                            ? ExternDeclDLLImportVisibility
754                            : ExternDeclNoDLLStorageClassVisibility);
755     } else {
756       GV.setVisibility(GV.getDLLStorageClass() ==
757                                llvm::GlobalValue::DLLExportStorageClass
758                            ? DLLExportVisibility
759                            : NoDLLStorageClassVisibility);
760     }
761 
762     GV.setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
763   }
764 }
765 
766 static bool isStackProtectorOn(const LangOptions &LangOpts,
767                                const llvm::Triple &Triple,
768                                clang::LangOptions::StackProtectorMode Mode) {
769   if (Triple.isAMDGPU() || Triple.isNVPTX())
770     return false;
771   return LangOpts.getStackProtector() == Mode;
772 }
773 
774 void CodeGenModule::Release() {
775   Module *Primary = getContext().getCurrentNamedModule();
776   if (CXX20ModuleInits && Primary && !Primary->isHeaderLikeModule())
777     EmitModuleInitializers(Primary);
778   EmitDeferred();
779   DeferredDecls.insert(EmittedDeferredDecls.begin(),
780                        EmittedDeferredDecls.end());
781   EmittedDeferredDecls.clear();
782   EmitVTablesOpportunistically();
783   applyGlobalValReplacements();
784   applyReplacements();
785   emitMultiVersionFunctions();
786 
787   if (Context.getLangOpts().IncrementalExtensions &&
788       GlobalTopLevelStmtBlockInFlight.first) {
789     const TopLevelStmtDecl *TLSD = GlobalTopLevelStmtBlockInFlight.second;
790     GlobalTopLevelStmtBlockInFlight.first->FinishFunction(TLSD->getEndLoc());
791     GlobalTopLevelStmtBlockInFlight = {nullptr, nullptr};
792   }
793 
794   // Module implementations are initialized the same way as a regular TU that
795   // imports one or more modules.
796   if (CXX20ModuleInits && Primary && Primary->isInterfaceOrPartition())
797     EmitCXXModuleInitFunc(Primary);
798   else
799     EmitCXXGlobalInitFunc();
800   EmitCXXGlobalCleanUpFunc();
801   registerGlobalDtorsWithAtExit();
802   EmitCXXThreadLocalInitFunc();
803   if (ObjCRuntime)
804     if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
805       AddGlobalCtor(ObjCInitFunction);
806   if (Context.getLangOpts().CUDA && CUDARuntime) {
807     if (llvm::Function *CudaCtorFunction = CUDARuntime->finalizeModule())
808       AddGlobalCtor(CudaCtorFunction);
809   }
810   if (OpenMPRuntime) {
811     if (llvm::Function *OpenMPRequiresDirectiveRegFun =
812             OpenMPRuntime->emitRequiresDirectiveRegFun()) {
813       AddGlobalCtor(OpenMPRequiresDirectiveRegFun, 0);
814     }
815     OpenMPRuntime->createOffloadEntriesAndInfoMetadata();
816     OpenMPRuntime->clear();
817   }
818   if (PGOReader) {
819     getModule().setProfileSummary(
820         PGOReader->getSummary(/* UseCS */ false).getMD(VMContext),
821         llvm::ProfileSummary::PSK_Instr);
822     if (PGOStats.hasDiagnostics())
823       PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName);
824   }
825   llvm::stable_sort(GlobalCtors, [](const Structor &L, const Structor &R) {
826     return L.LexOrder < R.LexOrder;
827   });
828   EmitCtorList(GlobalCtors, "llvm.global_ctors");
829   EmitCtorList(GlobalDtors, "llvm.global_dtors");
830   EmitGlobalAnnotations();
831   EmitStaticExternCAliases();
832   checkAliases();
833   EmitDeferredUnusedCoverageMappings();
834   CodeGenPGO(*this).setValueProfilingFlag(getModule());
835   if (CoverageMapping)
836     CoverageMapping->emit();
837   if (CodeGenOpts.SanitizeCfiCrossDso) {
838     CodeGenFunction(*this).EmitCfiCheckFail();
839     CodeGenFunction(*this).EmitCfiCheckStub();
840   }
841   if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
842     finalizeKCFITypes();
843   emitAtAvailableLinkGuard();
844   if (Context.getTargetInfo().getTriple().isWasm())
845     EmitMainVoidAlias();
846 
847   if (getTriple().isAMDGPU()) {
848     // Emit amdgpu_code_object_version module flag, which is code object version
849     // times 100.
850     if (getTarget().getTargetOpts().CodeObjectVersion !=
851         llvm::CodeObjectVersionKind::COV_None) {
852       getModule().addModuleFlag(llvm::Module::Error,
853                                 "amdgpu_code_object_version",
854                                 getTarget().getTargetOpts().CodeObjectVersion);
855     }
856 
857     // Currently, "-mprintf-kind" option is only supported for HIP
858     if (LangOpts.HIP) {
859       auto *MDStr = llvm::MDString::get(
860           getLLVMContext(), (getTarget().getTargetOpts().AMDGPUPrintfKindVal ==
861                              TargetOptions::AMDGPUPrintfKind::Hostcall)
862                                 ? "hostcall"
863                                 : "buffered");
864       getModule().addModuleFlag(llvm::Module::Error, "amdgpu_printf_kind",
865                                 MDStr);
866     }
867   }
868 
869   // Emit a global array containing all external kernels or device variables
870   // used by host functions and mark it as used for CUDA/HIP. This is necessary
871   // to get kernels or device variables in archives linked in even if these
872   // kernels or device variables are only used in host functions.
873   if (!Context.CUDAExternalDeviceDeclODRUsedByHost.empty()) {
874     SmallVector<llvm::Constant *, 8> UsedArray;
875     for (auto D : Context.CUDAExternalDeviceDeclODRUsedByHost) {
876       GlobalDecl GD;
877       if (auto *FD = dyn_cast<FunctionDecl>(D))
878         GD = GlobalDecl(FD, KernelReferenceKind::Kernel);
879       else
880         GD = GlobalDecl(D);
881       UsedArray.push_back(llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
882           GetAddrOfGlobal(GD), Int8PtrTy));
883     }
884 
885     llvm::ArrayType *ATy = llvm::ArrayType::get(Int8PtrTy, UsedArray.size());
886 
887     auto *GV = new llvm::GlobalVariable(
888         getModule(), ATy, false, llvm::GlobalValue::InternalLinkage,
889         llvm::ConstantArray::get(ATy, UsedArray), "__clang_gpu_used_external");
890     addCompilerUsedGlobal(GV);
891   }
892 
893   emitLLVMUsed();
894   if (SanStats)
895     SanStats->finish();
896 
897   if (CodeGenOpts.Autolink &&
898       (Context.getLangOpts().Modules || !LinkerOptionsMetadata.empty())) {
899     EmitModuleLinkOptions();
900   }
901 
902   // On ELF we pass the dependent library specifiers directly to the linker
903   // without manipulating them. This is in contrast to other platforms where
904   // they are mapped to a specific linker option by the compiler. This
905   // difference is a result of the greater variety of ELF linkers and the fact
906   // that ELF linkers tend to handle libraries in a more complicated fashion
907   // than on other platforms. This forces us to defer handling the dependent
908   // libs to the linker.
909   //
910   // CUDA/HIP device and host libraries are different. Currently there is no
911   // way to differentiate dependent libraries for host or device. Existing
912   // usage of #pragma comment(lib, *) is intended for host libraries on
913   // Windows. Therefore emit llvm.dependent-libraries only for host.
914   if (!ELFDependentLibraries.empty() && !Context.getLangOpts().CUDAIsDevice) {
915     auto *NMD = getModule().getOrInsertNamedMetadata("llvm.dependent-libraries");
916     for (auto *MD : ELFDependentLibraries)
917       NMD->addOperand(MD);
918   }
919 
920   // Record mregparm value now so it is visible through rest of codegen.
921   if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
922     getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
923                               CodeGenOpts.NumRegisterParameters);
924 
925   if (CodeGenOpts.DwarfVersion) {
926     getModule().addModuleFlag(llvm::Module::Max, "Dwarf Version",
927                               CodeGenOpts.DwarfVersion);
928   }
929 
930   if (CodeGenOpts.Dwarf64)
931     getModule().addModuleFlag(llvm::Module::Max, "DWARF64", 1);
932 
933   if (Context.getLangOpts().SemanticInterposition)
934     // Require various optimization to respect semantic interposition.
935     getModule().setSemanticInterposition(true);
936 
937   if (CodeGenOpts.EmitCodeView) {
938     // Indicate that we want CodeView in the metadata.
939     getModule().addModuleFlag(llvm::Module::Warning, "CodeView", 1);
940   }
941   if (CodeGenOpts.CodeViewGHash) {
942     getModule().addModuleFlag(llvm::Module::Warning, "CodeViewGHash", 1);
943   }
944   if (CodeGenOpts.ControlFlowGuard) {
945     // Function ID tables and checks for Control Flow Guard (cfguard=2).
946     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 2);
947   } else if (CodeGenOpts.ControlFlowGuardNoChecks) {
948     // Function ID tables for Control Flow Guard (cfguard=1).
949     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 1);
950   }
951   if (CodeGenOpts.EHContGuard) {
952     // Function ID tables for EH Continuation Guard.
953     getModule().addModuleFlag(llvm::Module::Warning, "ehcontguard", 1);
954   }
955   if (Context.getLangOpts().Kernel) {
956     // Note if we are compiling with /kernel.
957     getModule().addModuleFlag(llvm::Module::Warning, "ms-kernel", 1);
958   }
959   if (CodeGenOpts.OptimizationLevel > 0 && CodeGenOpts.StrictVTablePointers) {
960     // We don't support LTO with 2 with different StrictVTablePointers
961     // FIXME: we could support it by stripping all the information introduced
962     // by StrictVTablePointers.
963 
964     getModule().addModuleFlag(llvm::Module::Error, "StrictVTablePointers",1);
965 
966     llvm::Metadata *Ops[2] = {
967               llvm::MDString::get(VMContext, "StrictVTablePointers"),
968               llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
969                   llvm::Type::getInt32Ty(VMContext), 1))};
970 
971     getModule().addModuleFlag(llvm::Module::Require,
972                               "StrictVTablePointersRequirement",
973                               llvm::MDNode::get(VMContext, Ops));
974   }
975   if (getModuleDebugInfo())
976     // We support a single version in the linked module. The LLVM
977     // parser will drop debug info with a different version number
978     // (and warn about it, too).
979     getModule().addModuleFlag(llvm::Module::Warning, "Debug Info Version",
980                               llvm::DEBUG_METADATA_VERSION);
981 
982   // We need to record the widths of enums and wchar_t, so that we can generate
983   // the correct build attributes in the ARM backend. wchar_size is also used by
984   // TargetLibraryInfo.
985   uint64_t WCharWidth =
986       Context.getTypeSizeInChars(Context.getWideCharType()).getQuantity();
987   getModule().addModuleFlag(llvm::Module::Error, "wchar_size", WCharWidth);
988 
989   if (getTriple().isOSzOS()) {
990     getModule().addModuleFlag(llvm::Module::Warning,
991                               "zos_product_major_version",
992                               uint32_t(CLANG_VERSION_MAJOR));
993     getModule().addModuleFlag(llvm::Module::Warning,
994                               "zos_product_minor_version",
995                               uint32_t(CLANG_VERSION_MINOR));
996     getModule().addModuleFlag(llvm::Module::Warning, "zos_product_patchlevel",
997                               uint32_t(CLANG_VERSION_PATCHLEVEL));
998     std::string ProductId;
999 #ifdef CLANG_VENDOR
1000     ProductId = #CLANG_VENDOR;
1001 #else
1002     ProductId = "clang";
1003 #endif
1004     getModule().addModuleFlag(llvm::Module::Error, "zos_product_id",
1005                               llvm::MDString::get(VMContext, ProductId));
1006 
1007     // Record the language because we need it for the PPA2.
1008     StringRef lang_str = languageToString(
1009         LangStandard::getLangStandardForKind(LangOpts.LangStd).Language);
1010     getModule().addModuleFlag(llvm::Module::Error, "zos_cu_language",
1011                               llvm::MDString::get(VMContext, lang_str));
1012 
1013     time_t TT = PreprocessorOpts.SourceDateEpoch
1014                     ? *PreprocessorOpts.SourceDateEpoch
1015                     : std::time(nullptr);
1016     getModule().addModuleFlag(llvm::Module::Max, "zos_translation_time",
1017                               static_cast<uint64_t>(TT));
1018 
1019     // Multiple modes will be supported here.
1020     getModule().addModuleFlag(llvm::Module::Error, "zos_le_char_mode",
1021                               llvm::MDString::get(VMContext, "ascii"));
1022   }
1023 
1024   llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
1025   if (   Arch == llvm::Triple::arm
1026       || Arch == llvm::Triple::armeb
1027       || Arch == llvm::Triple::thumb
1028       || Arch == llvm::Triple::thumbeb) {
1029     // The minimum width of an enum in bytes
1030     uint64_t EnumWidth = Context.getLangOpts().ShortEnums ? 1 : 4;
1031     getModule().addModuleFlag(llvm::Module::Error, "min_enum_size", EnumWidth);
1032   }
1033 
1034   if (Arch == llvm::Triple::riscv32 || Arch == llvm::Triple::riscv64) {
1035     StringRef ABIStr = Target.getABI();
1036     llvm::LLVMContext &Ctx = TheModule.getContext();
1037     getModule().addModuleFlag(llvm::Module::Error, "target-abi",
1038                               llvm::MDString::get(Ctx, ABIStr));
1039   }
1040 
1041   if (CodeGenOpts.SanitizeCfiCrossDso) {
1042     // Indicate that we want cross-DSO control flow integrity checks.
1043     getModule().addModuleFlag(llvm::Module::Override, "Cross-DSO CFI", 1);
1044   }
1045 
1046   if (CodeGenOpts.WholeProgramVTables) {
1047     // Indicate whether VFE was enabled for this module, so that the
1048     // vcall_visibility metadata added under whole program vtables is handled
1049     // appropriately in the optimizer.
1050     getModule().addModuleFlag(llvm::Module::Error, "Virtual Function Elim",
1051                               CodeGenOpts.VirtualFunctionElimination);
1052   }
1053 
1054   if (LangOpts.Sanitize.has(SanitizerKind::CFIICall)) {
1055     getModule().addModuleFlag(llvm::Module::Override,
1056                               "CFI Canonical Jump Tables",
1057                               CodeGenOpts.SanitizeCfiCanonicalJumpTables);
1058   }
1059 
1060   if (LangOpts.Sanitize.has(SanitizerKind::KCFI)) {
1061     getModule().addModuleFlag(llvm::Module::Override, "kcfi", 1);
1062     // KCFI assumes patchable-function-prefix is the same for all indirectly
1063     // called functions. Store the expected offset for code generation.
1064     if (CodeGenOpts.PatchableFunctionEntryOffset)
1065       getModule().addModuleFlag(llvm::Module::Override, "kcfi-offset",
1066                                 CodeGenOpts.PatchableFunctionEntryOffset);
1067   }
1068 
1069   if (CodeGenOpts.CFProtectionReturn &&
1070       Target.checkCFProtectionReturnSupported(getDiags())) {
1071     // Indicate that we want to instrument return control flow protection.
1072     getModule().addModuleFlag(llvm::Module::Min, "cf-protection-return",
1073                               1);
1074   }
1075 
1076   if (CodeGenOpts.CFProtectionBranch &&
1077       Target.checkCFProtectionBranchSupported(getDiags())) {
1078     // Indicate that we want to instrument branch control flow protection.
1079     getModule().addModuleFlag(llvm::Module::Min, "cf-protection-branch",
1080                               1);
1081   }
1082 
1083   if (CodeGenOpts.FunctionReturnThunks)
1084     getModule().addModuleFlag(llvm::Module::Override, "function_return_thunk_extern", 1);
1085 
1086   if (CodeGenOpts.IndirectBranchCSPrefix)
1087     getModule().addModuleFlag(llvm::Module::Override, "indirect_branch_cs_prefix", 1);
1088 
1089   // Add module metadata for return address signing (ignoring
1090   // non-leaf/all) and stack tagging. These are actually turned on by function
1091   // attributes, but we use module metadata to emit build attributes. This is
1092   // needed for LTO, where the function attributes are inside bitcode
1093   // serialised into a global variable by the time build attributes are
1094   // emitted, so we can't access them. LTO objects could be compiled with
1095   // different flags therefore module flags are set to "Min" behavior to achieve
1096   // the same end result of the normal build where e.g BTI is off if any object
1097   // doesn't support it.
1098   if (Context.getTargetInfo().hasFeature("ptrauth") &&
1099       LangOpts.getSignReturnAddressScope() !=
1100           LangOptions::SignReturnAddressScopeKind::None)
1101     getModule().addModuleFlag(llvm::Module::Override,
1102                               "sign-return-address-buildattr", 1);
1103   if (LangOpts.Sanitize.has(SanitizerKind::MemtagStack))
1104     getModule().addModuleFlag(llvm::Module::Override,
1105                               "tag-stack-memory-buildattr", 1);
1106 
1107   if (Arch == llvm::Triple::thumb || Arch == llvm::Triple::thumbeb ||
1108       Arch == llvm::Triple::arm || Arch == llvm::Triple::armeb ||
1109       Arch == llvm::Triple::aarch64 || Arch == llvm::Triple::aarch64_32 ||
1110       Arch == llvm::Triple::aarch64_be) {
1111     if (LangOpts.BranchTargetEnforcement)
1112       getModule().addModuleFlag(llvm::Module::Min, "branch-target-enforcement",
1113                                 1);
1114     if (LangOpts.hasSignReturnAddress())
1115       getModule().addModuleFlag(llvm::Module::Min, "sign-return-address", 1);
1116     if (LangOpts.isSignReturnAddressScopeAll())
1117       getModule().addModuleFlag(llvm::Module::Min, "sign-return-address-all",
1118                                 1);
1119     if (!LangOpts.isSignReturnAddressWithAKey())
1120       getModule().addModuleFlag(llvm::Module::Min,
1121                                 "sign-return-address-with-bkey", 1);
1122   }
1123 
1124   if (!CodeGenOpts.MemoryProfileOutput.empty()) {
1125     llvm::LLVMContext &Ctx = TheModule.getContext();
1126     getModule().addModuleFlag(
1127         llvm::Module::Error, "MemProfProfileFilename",
1128         llvm::MDString::get(Ctx, CodeGenOpts.MemoryProfileOutput));
1129   }
1130 
1131   if (LangOpts.CUDAIsDevice && getTriple().isNVPTX()) {
1132     // Indicate whether __nvvm_reflect should be configured to flush denormal
1133     // floating point values to 0.  (This corresponds to its "__CUDA_FTZ"
1134     // property.)
1135     getModule().addModuleFlag(llvm::Module::Override, "nvvm-reflect-ftz",
1136                               CodeGenOpts.FP32DenormalMode.Output !=
1137                                   llvm::DenormalMode::IEEE);
1138   }
1139 
1140   if (LangOpts.EHAsynch)
1141     getModule().addModuleFlag(llvm::Module::Warning, "eh-asynch", 1);
1142 
1143   // Indicate whether this Module was compiled with -fopenmp
1144   if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
1145     getModule().addModuleFlag(llvm::Module::Max, "openmp", LangOpts.OpenMP);
1146   if (getLangOpts().OpenMPIsTargetDevice)
1147     getModule().addModuleFlag(llvm::Module::Max, "openmp-device",
1148                               LangOpts.OpenMP);
1149 
1150   // Emit OpenCL specific module metadata: OpenCL/SPIR version.
1151   if (LangOpts.OpenCL || (LangOpts.CUDAIsDevice && getTriple().isSPIRV())) {
1152     EmitOpenCLMetadata();
1153     // Emit SPIR version.
1154     if (getTriple().isSPIR()) {
1155       // SPIR v2.0 s2.12 - The SPIR version used by the module is stored in the
1156       // opencl.spir.version named metadata.
1157       // C++ for OpenCL has a distinct mapping for version compatibility with
1158       // OpenCL.
1159       auto Version = LangOpts.getOpenCLCompatibleVersion();
1160       llvm::Metadata *SPIRVerElts[] = {
1161           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1162               Int32Ty, Version / 100)),
1163           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1164               Int32Ty, (Version / 100 > 1) ? 0 : 2))};
1165       llvm::NamedMDNode *SPIRVerMD =
1166           TheModule.getOrInsertNamedMetadata("opencl.spir.version");
1167       llvm::LLVMContext &Ctx = TheModule.getContext();
1168       SPIRVerMD->addOperand(llvm::MDNode::get(Ctx, SPIRVerElts));
1169     }
1170   }
1171 
1172   // HLSL related end of code gen work items.
1173   if (LangOpts.HLSL)
1174     getHLSLRuntime().finishCodeGen();
1175 
1176   if (uint32_t PLevel = Context.getLangOpts().PICLevel) {
1177     assert(PLevel < 3 && "Invalid PIC Level");
1178     getModule().setPICLevel(static_cast<llvm::PICLevel::Level>(PLevel));
1179     if (Context.getLangOpts().PIE)
1180       getModule().setPIELevel(static_cast<llvm::PIELevel::Level>(PLevel));
1181   }
1182 
1183   if (getCodeGenOpts().CodeModel.size() > 0) {
1184     unsigned CM = llvm::StringSwitch<unsigned>(getCodeGenOpts().CodeModel)
1185                   .Case("tiny", llvm::CodeModel::Tiny)
1186                   .Case("small", llvm::CodeModel::Small)
1187                   .Case("kernel", llvm::CodeModel::Kernel)
1188                   .Case("medium", llvm::CodeModel::Medium)
1189                   .Case("large", llvm::CodeModel::Large)
1190                   .Default(~0u);
1191     if (CM != ~0u) {
1192       llvm::CodeModel::Model codeModel = static_cast<llvm::CodeModel::Model>(CM);
1193       getModule().setCodeModel(codeModel);
1194 
1195       if (CM == llvm::CodeModel::Medium &&
1196           Context.getTargetInfo().getTriple().getArch() ==
1197               llvm::Triple::x86_64) {
1198         getModule().setLargeDataThreshold(getCodeGenOpts().LargeDataThreshold);
1199       }
1200     }
1201   }
1202 
1203   if (CodeGenOpts.NoPLT)
1204     getModule().setRtLibUseGOT();
1205   if (getTriple().isOSBinFormatELF() &&
1206       CodeGenOpts.DirectAccessExternalData !=
1207           getModule().getDirectAccessExternalData()) {
1208     getModule().setDirectAccessExternalData(
1209         CodeGenOpts.DirectAccessExternalData);
1210   }
1211   if (CodeGenOpts.UnwindTables)
1212     getModule().setUwtable(llvm::UWTableKind(CodeGenOpts.UnwindTables));
1213 
1214   switch (CodeGenOpts.getFramePointer()) {
1215   case CodeGenOptions::FramePointerKind::None:
1216     // 0 ("none") is the default.
1217     break;
1218   case CodeGenOptions::FramePointerKind::NonLeaf:
1219     getModule().setFramePointer(llvm::FramePointerKind::NonLeaf);
1220     break;
1221   case CodeGenOptions::FramePointerKind::All:
1222     getModule().setFramePointer(llvm::FramePointerKind::All);
1223     break;
1224   }
1225 
1226   SimplifyPersonality();
1227 
1228   if (getCodeGenOpts().EmitDeclMetadata)
1229     EmitDeclMetadata();
1230 
1231   if (getCodeGenOpts().CoverageNotesFile.size() ||
1232       getCodeGenOpts().CoverageDataFile.size())
1233     EmitCoverageFile();
1234 
1235   if (CGDebugInfo *DI = getModuleDebugInfo())
1236     DI->finalize();
1237 
1238   if (getCodeGenOpts().EmitVersionIdentMetadata)
1239     EmitVersionIdentMetadata();
1240 
1241   if (!getCodeGenOpts().RecordCommandLine.empty())
1242     EmitCommandLineMetadata();
1243 
1244   if (!getCodeGenOpts().StackProtectorGuard.empty())
1245     getModule().setStackProtectorGuard(getCodeGenOpts().StackProtectorGuard);
1246   if (!getCodeGenOpts().StackProtectorGuardReg.empty())
1247     getModule().setStackProtectorGuardReg(
1248         getCodeGenOpts().StackProtectorGuardReg);
1249   if (!getCodeGenOpts().StackProtectorGuardSymbol.empty())
1250     getModule().setStackProtectorGuardSymbol(
1251         getCodeGenOpts().StackProtectorGuardSymbol);
1252   if (getCodeGenOpts().StackProtectorGuardOffset != INT_MAX)
1253     getModule().setStackProtectorGuardOffset(
1254         getCodeGenOpts().StackProtectorGuardOffset);
1255   if (getCodeGenOpts().StackAlignment)
1256     getModule().setOverrideStackAlignment(getCodeGenOpts().StackAlignment);
1257   if (getCodeGenOpts().SkipRaxSetup)
1258     getModule().addModuleFlag(llvm::Module::Override, "SkipRaxSetup", 1);
1259   if (getLangOpts().RegCall4)
1260     getModule().addModuleFlag(llvm::Module::Override, "RegCallv4", 1);
1261 
1262   if (getContext().getTargetInfo().getMaxTLSAlign())
1263     getModule().addModuleFlag(llvm::Module::Error, "MaxTLSAlign",
1264                               getContext().getTargetInfo().getMaxTLSAlign());
1265 
1266   getTargetCodeGenInfo().emitTargetGlobals(*this);
1267 
1268   getTargetCodeGenInfo().emitTargetMetadata(*this, MangledDeclNames);
1269 
1270   EmitBackendOptionsMetadata(getCodeGenOpts());
1271 
1272   // If there is device offloading code embed it in the host now.
1273   EmbedObject(&getModule(), CodeGenOpts, getDiags());
1274 
1275   // Set visibility from DLL storage class
1276   // We do this at the end of LLVM IR generation; after any operation
1277   // that might affect the DLL storage class or the visibility, and
1278   // before anything that might act on these.
1279   setVisibilityFromDLLStorageClass(LangOpts, getModule());
1280 }
1281 
1282 void CodeGenModule::EmitOpenCLMetadata() {
1283   // SPIR v2.0 s2.13 - The OpenCL version used by the module is stored in the
1284   // opencl.ocl.version named metadata node.
1285   // C++ for OpenCL has a distinct mapping for versions compatibile with OpenCL.
1286   auto Version = LangOpts.getOpenCLCompatibleVersion();
1287   llvm::Metadata *OCLVerElts[] = {
1288       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1289           Int32Ty, Version / 100)),
1290       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
1291           Int32Ty, (Version % 100) / 10))};
1292   llvm::NamedMDNode *OCLVerMD =
1293       TheModule.getOrInsertNamedMetadata("opencl.ocl.version");
1294   llvm::LLVMContext &Ctx = TheModule.getContext();
1295   OCLVerMD->addOperand(llvm::MDNode::get(Ctx, OCLVerElts));
1296 }
1297 
1298 void CodeGenModule::EmitBackendOptionsMetadata(
1299     const CodeGenOptions &CodeGenOpts) {
1300   if (getTriple().isRISCV()) {
1301     getModule().addModuleFlag(llvm::Module::Min, "SmallDataLimit",
1302                               CodeGenOpts.SmallDataLimit);
1303   }
1304 }
1305 
1306 void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
1307   // Make sure that this type is translated.
1308   Types.UpdateCompletedType(TD);
1309 }
1310 
1311 void CodeGenModule::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
1312   // Make sure that this type is translated.
1313   Types.RefreshTypeCacheForClass(RD);
1314 }
1315 
1316 llvm::MDNode *CodeGenModule::getTBAATypeInfo(QualType QTy) {
1317   if (!TBAA)
1318     return nullptr;
1319   return TBAA->getTypeInfo(QTy);
1320 }
1321 
1322 TBAAAccessInfo CodeGenModule::getTBAAAccessInfo(QualType AccessType) {
1323   if (!TBAA)
1324     return TBAAAccessInfo();
1325   if (getLangOpts().CUDAIsDevice) {
1326     // As CUDA builtin surface/texture types are replaced, skip generating TBAA
1327     // access info.
1328     if (AccessType->isCUDADeviceBuiltinSurfaceType()) {
1329       if (getTargetCodeGenInfo().getCUDADeviceBuiltinSurfaceDeviceType() !=
1330           nullptr)
1331         return TBAAAccessInfo();
1332     } else if (AccessType->isCUDADeviceBuiltinTextureType()) {
1333       if (getTargetCodeGenInfo().getCUDADeviceBuiltinTextureDeviceType() !=
1334           nullptr)
1335         return TBAAAccessInfo();
1336     }
1337   }
1338   return TBAA->getAccessInfo(AccessType);
1339 }
1340 
1341 TBAAAccessInfo
1342 CodeGenModule::getTBAAVTablePtrAccessInfo(llvm::Type *VTablePtrType) {
1343   if (!TBAA)
1344     return TBAAAccessInfo();
1345   return TBAA->getVTablePtrAccessInfo(VTablePtrType);
1346 }
1347 
1348 llvm::MDNode *CodeGenModule::getTBAAStructInfo(QualType QTy) {
1349   if (!TBAA)
1350     return nullptr;
1351   return TBAA->getTBAAStructInfo(QTy);
1352 }
1353 
1354 llvm::MDNode *CodeGenModule::getTBAABaseTypeInfo(QualType QTy) {
1355   if (!TBAA)
1356     return nullptr;
1357   return TBAA->getBaseTypeInfo(QTy);
1358 }
1359 
1360 llvm::MDNode *CodeGenModule::getTBAAAccessTagInfo(TBAAAccessInfo Info) {
1361   if (!TBAA)
1362     return nullptr;
1363   return TBAA->getAccessTagInfo(Info);
1364 }
1365 
1366 TBAAAccessInfo CodeGenModule::mergeTBAAInfoForCast(TBAAAccessInfo SourceInfo,
1367                                                    TBAAAccessInfo TargetInfo) {
1368   if (!TBAA)
1369     return TBAAAccessInfo();
1370   return TBAA->mergeTBAAInfoForCast(SourceInfo, TargetInfo);
1371 }
1372 
1373 TBAAAccessInfo
1374 CodeGenModule::mergeTBAAInfoForConditionalOperator(TBAAAccessInfo InfoA,
1375                                                    TBAAAccessInfo InfoB) {
1376   if (!TBAA)
1377     return TBAAAccessInfo();
1378   return TBAA->mergeTBAAInfoForConditionalOperator(InfoA, InfoB);
1379 }
1380 
1381 TBAAAccessInfo
1382 CodeGenModule::mergeTBAAInfoForMemoryTransfer(TBAAAccessInfo DestInfo,
1383                                               TBAAAccessInfo SrcInfo) {
1384   if (!TBAA)
1385     return TBAAAccessInfo();
1386   return TBAA->mergeTBAAInfoForConditionalOperator(DestInfo, SrcInfo);
1387 }
1388 
1389 void CodeGenModule::DecorateInstructionWithTBAA(llvm::Instruction *Inst,
1390                                                 TBAAAccessInfo TBAAInfo) {
1391   if (llvm::MDNode *Tag = getTBAAAccessTagInfo(TBAAInfo))
1392     Inst->setMetadata(llvm::LLVMContext::MD_tbaa, Tag);
1393 }
1394 
1395 void CodeGenModule::DecorateInstructionWithInvariantGroup(
1396     llvm::Instruction *I, const CXXRecordDecl *RD) {
1397   I->setMetadata(llvm::LLVMContext::MD_invariant_group,
1398                  llvm::MDNode::get(getLLVMContext(), {}));
1399 }
1400 
1401 void CodeGenModule::Error(SourceLocation loc, StringRef message) {
1402   unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
1403   getDiags().Report(Context.getFullLoc(loc), diagID) << message;
1404 }
1405 
1406 /// ErrorUnsupported - Print out an error that codegen doesn't support the
1407 /// specified stmt yet.
1408 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type) {
1409   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
1410                                                "cannot compile this %0 yet");
1411   std::string Msg = Type;
1412   getDiags().Report(Context.getFullLoc(S->getBeginLoc()), DiagID)
1413       << Msg << S->getSourceRange();
1414 }
1415 
1416 /// ErrorUnsupported - Print out an error that codegen doesn't support the
1417 /// specified decl yet.
1418 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type) {
1419   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
1420                                                "cannot compile this %0 yet");
1421   std::string Msg = Type;
1422   getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
1423 }
1424 
1425 llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) {
1426   return llvm::ConstantInt::get(SizeTy, size.getQuantity());
1427 }
1428 
1429 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
1430                                         const NamedDecl *D) const {
1431   // Internal definitions always have default visibility.
1432   if (GV->hasLocalLinkage()) {
1433     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
1434     return;
1435   }
1436   if (!D)
1437     return;
1438 
1439   // Set visibility for definitions, and for declarations if requested globally
1440   // or set explicitly.
1441   LinkageInfo LV = D->getLinkageAndVisibility();
1442 
1443   // OpenMP declare target variables must be visible to the host so they can
1444   // be registered. We require protected visibility unless the variable has
1445   // the DT_nohost modifier and does not need to be registered.
1446   if (Context.getLangOpts().OpenMP &&
1447       Context.getLangOpts().OpenMPIsTargetDevice && isa<VarDecl>(D) &&
1448       D->hasAttr<OMPDeclareTargetDeclAttr>() &&
1449       D->getAttr<OMPDeclareTargetDeclAttr>()->getDevType() !=
1450           OMPDeclareTargetDeclAttr::DT_NoHost &&
1451       LV.getVisibility() == HiddenVisibility) {
1452     GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
1453     return;
1454   }
1455 
1456   if (GV->hasDLLExportStorageClass() || GV->hasDLLImportStorageClass()) {
1457     // Reject incompatible dlllstorage and visibility annotations.
1458     if (!LV.isVisibilityExplicit())
1459       return;
1460     if (GV->hasDLLExportStorageClass()) {
1461       if (LV.getVisibility() == HiddenVisibility)
1462         getDiags().Report(D->getLocation(),
1463                           diag::err_hidden_visibility_dllexport);
1464     } else if (LV.getVisibility() != DefaultVisibility) {
1465       getDiags().Report(D->getLocation(),
1466                         diag::err_non_default_visibility_dllimport);
1467     }
1468     return;
1469   }
1470 
1471   if (LV.isVisibilityExplicit() || getLangOpts().SetVisibilityForExternDecls ||
1472       !GV->isDeclarationForLinker())
1473     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
1474 }
1475 
1476 static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
1477                                  llvm::GlobalValue *GV) {
1478   if (GV->hasLocalLinkage())
1479     return true;
1480 
1481   if (!GV->hasDefaultVisibility() && !GV->hasExternalWeakLinkage())
1482     return true;
1483 
1484   // DLLImport explicitly marks the GV as external.
1485   if (GV->hasDLLImportStorageClass())
1486     return false;
1487 
1488   const llvm::Triple &TT = CGM.getTriple();
1489   const auto &CGOpts = CGM.getCodeGenOpts();
1490   if (TT.isWindowsGNUEnvironment()) {
1491     // In MinGW, variables without DLLImport can still be automatically
1492     // imported from a DLL by the linker; don't mark variables that
1493     // potentially could come from another DLL as DSO local.
1494 
1495     // With EmulatedTLS, TLS variables can be autoimported from other DLLs
1496     // (and this actually happens in the public interface of libstdc++), so
1497     // such variables can't be marked as DSO local. (Native TLS variables
1498     // can't be dllimported at all, though.)
1499     if (GV->isDeclarationForLinker() && isa<llvm::GlobalVariable>(GV) &&
1500         (!GV->isThreadLocal() || CGM.getCodeGenOpts().EmulatedTLS) &&
1501         CGOpts.AutoImport)
1502       return false;
1503   }
1504 
1505   // On COFF, don't mark 'extern_weak' symbols as DSO local. If these symbols
1506   // remain unresolved in the link, they can be resolved to zero, which is
1507   // outside the current DSO.
1508   if (TT.isOSBinFormatCOFF() && GV->hasExternalWeakLinkage())
1509     return false;
1510 
1511   // Every other GV is local on COFF.
1512   // Make an exception for windows OS in the triple: Some firmware builds use
1513   // *-win32-macho triples. This (accidentally?) produced windows relocations
1514   // without GOT tables in older clang versions; Keep this behaviour.
1515   // FIXME: even thread local variables?
1516   if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO()))
1517     return true;
1518 
1519   // Only handle COFF and ELF for now.
1520   if (!TT.isOSBinFormatELF())
1521     return false;
1522 
1523   // If this is not an executable, don't assume anything is local.
1524   llvm::Reloc::Model RM = CGOpts.RelocationModel;
1525   const auto &LOpts = CGM.getLangOpts();
1526   if (RM != llvm::Reloc::Static && !LOpts.PIE) {
1527     // On ELF, if -fno-semantic-interposition is specified and the target
1528     // supports local aliases, there will be neither CC1
1529     // -fsemantic-interposition nor -fhalf-no-semantic-interposition. Set
1530     // dso_local on the function if using a local alias is preferable (can avoid
1531     // PLT indirection).
1532     if (!(isa<llvm::Function>(GV) && GV->canBenefitFromLocalAlias()))
1533       return false;
1534     return !(CGM.getLangOpts().SemanticInterposition ||
1535              CGM.getLangOpts().HalfNoSemanticInterposition);
1536   }
1537 
1538   // A definition cannot be preempted from an executable.
1539   if (!GV->isDeclarationForLinker())
1540     return true;
1541 
1542   // Most PIC code sequences that assume that a symbol is local cannot produce a
1543   // 0 if it turns out the symbol is undefined. While this is ABI and relocation
1544   // depended, it seems worth it to handle it here.
1545   if (RM == llvm::Reloc::PIC_ && GV->hasExternalWeakLinkage())
1546     return false;
1547 
1548   // PowerPC64 prefers TOC indirection to avoid copy relocations.
1549   if (TT.isPPC64())
1550     return false;
1551 
1552   if (CGOpts.DirectAccessExternalData) {
1553     // If -fdirect-access-external-data (default for -fno-pic), set dso_local
1554     // for non-thread-local variables. If the symbol is not defined in the
1555     // executable, a copy relocation will be needed at link time. dso_local is
1556     // excluded for thread-local variables because they generally don't support
1557     // copy relocations.
1558     if (auto *Var = dyn_cast<llvm::GlobalVariable>(GV))
1559       if (!Var->isThreadLocal())
1560         return true;
1561 
1562     // -fno-pic sets dso_local on a function declaration to allow direct
1563     // accesses when taking its address (similar to a data symbol). If the
1564     // function is not defined in the executable, a canonical PLT entry will be
1565     // needed at link time. -fno-direct-access-external-data can avoid the
1566     // canonical PLT entry. We don't generalize this condition to -fpie/-fpic as
1567     // it could just cause trouble without providing perceptible benefits.
1568     if (isa<llvm::Function>(GV) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
1569       return true;
1570   }
1571 
1572   // If we can use copy relocations we can assume it is local.
1573 
1574   // Otherwise don't assume it is local.
1575   return false;
1576 }
1577 
1578 void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV) const {
1579   GV->setDSOLocal(shouldAssumeDSOLocal(*this, GV));
1580 }
1581 
1582 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
1583                                           GlobalDecl GD) const {
1584   const auto *D = dyn_cast<NamedDecl>(GD.getDecl());
1585   // C++ destructors have a few C++ ABI specific special cases.
1586   if (const auto *Dtor = dyn_cast_or_null<CXXDestructorDecl>(D)) {
1587     getCXXABI().setCXXDestructorDLLStorage(GV, Dtor, GD.getDtorType());
1588     return;
1589   }
1590   setDLLImportDLLExport(GV, D);
1591 }
1592 
1593 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
1594                                           const NamedDecl *D) const {
1595   if (D && D->isExternallyVisible()) {
1596     if (D->hasAttr<DLLImportAttr>())
1597       GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
1598     else if ((D->hasAttr<DLLExportAttr>() ||
1599               shouldMapVisibilityToDLLExport(D)) &&
1600              !GV->isDeclarationForLinker())
1601       GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
1602   }
1603 }
1604 
1605 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
1606                                     GlobalDecl GD) const {
1607   setDLLImportDLLExport(GV, GD);
1608   setGVPropertiesAux(GV, dyn_cast<NamedDecl>(GD.getDecl()));
1609 }
1610 
1611 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
1612                                     const NamedDecl *D) const {
1613   setDLLImportDLLExport(GV, D);
1614   setGVPropertiesAux(GV, D);
1615 }
1616 
1617 void CodeGenModule::setGVPropertiesAux(llvm::GlobalValue *GV,
1618                                        const NamedDecl *D) const {
1619   setGlobalVisibility(GV, D);
1620   setDSOLocal(GV);
1621   GV->setPartition(CodeGenOpts.SymbolPartition);
1622 }
1623 
1624 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) {
1625   return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S)
1626       .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel)
1627       .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel)
1628       .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel)
1629       .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel);
1630 }
1631 
1632 llvm::GlobalVariable::ThreadLocalMode
1633 CodeGenModule::GetDefaultLLVMTLSModel() const {
1634   switch (CodeGenOpts.getDefaultTLSModel()) {
1635   case CodeGenOptions::GeneralDynamicTLSModel:
1636     return llvm::GlobalVariable::GeneralDynamicTLSModel;
1637   case CodeGenOptions::LocalDynamicTLSModel:
1638     return llvm::GlobalVariable::LocalDynamicTLSModel;
1639   case CodeGenOptions::InitialExecTLSModel:
1640     return llvm::GlobalVariable::InitialExecTLSModel;
1641   case CodeGenOptions::LocalExecTLSModel:
1642     return llvm::GlobalVariable::LocalExecTLSModel;
1643   }
1644   llvm_unreachable("Invalid TLS model!");
1645 }
1646 
1647 void CodeGenModule::setTLSMode(llvm::GlobalValue *GV, const VarDecl &D) const {
1648   assert(D.getTLSKind() && "setting TLS mode on non-TLS var!");
1649 
1650   llvm::GlobalValue::ThreadLocalMode TLM;
1651   TLM = GetDefaultLLVMTLSModel();
1652 
1653   // Override the TLS model if it is explicitly specified.
1654   if (const TLSModelAttr *Attr = D.getAttr<TLSModelAttr>()) {
1655     TLM = GetLLVMTLSModel(Attr->getModel());
1656   }
1657 
1658   GV->setThreadLocalMode(TLM);
1659 }
1660 
1661 static std::string getCPUSpecificMangling(const CodeGenModule &CGM,
1662                                           StringRef Name) {
1663   const TargetInfo &Target = CGM.getTarget();
1664   return (Twine('.') + Twine(Target.CPUSpecificManglingCharacter(Name))).str();
1665 }
1666 
1667 static void AppendCPUSpecificCPUDispatchMangling(const CodeGenModule &CGM,
1668                                                  const CPUSpecificAttr *Attr,
1669                                                  unsigned CPUIndex,
1670                                                  raw_ostream &Out) {
1671   // cpu_specific gets the current name, dispatch gets the resolver if IFunc is
1672   // supported.
1673   if (Attr)
1674     Out << getCPUSpecificMangling(CGM, Attr->getCPUName(CPUIndex)->getName());
1675   else if (CGM.getTarget().supportsIFunc())
1676     Out << ".resolver";
1677 }
1678 
1679 static void AppendTargetVersionMangling(const CodeGenModule &CGM,
1680                                         const TargetVersionAttr *Attr,
1681                                         raw_ostream &Out) {
1682   if (Attr->isDefaultVersion())
1683     return;
1684   Out << "._";
1685   const TargetInfo &TI = CGM.getTarget();
1686   llvm::SmallVector<StringRef, 8> Feats;
1687   Attr->getFeatures(Feats);
1688   llvm::stable_sort(Feats, [&TI](const StringRef FeatL, const StringRef FeatR) {
1689     return TI.multiVersionSortPriority(FeatL) <
1690            TI.multiVersionSortPriority(FeatR);
1691   });
1692   for (const auto &Feat : Feats) {
1693     Out << 'M';
1694     Out << Feat;
1695   }
1696 }
1697 
1698 static void AppendTargetMangling(const CodeGenModule &CGM,
1699                                  const TargetAttr *Attr, raw_ostream &Out) {
1700   if (Attr->isDefaultVersion())
1701     return;
1702 
1703   Out << '.';
1704   const TargetInfo &Target = CGM.getTarget();
1705   ParsedTargetAttr Info = Target.parseTargetAttr(Attr->getFeaturesStr());
1706   llvm::sort(Info.Features, [&Target](StringRef LHS, StringRef RHS) {
1707     // Multiversioning doesn't allow "no-${feature}", so we can
1708     // only have "+" prefixes here.
1709     assert(LHS.startswith("+") && RHS.startswith("+") &&
1710            "Features should always have a prefix.");
1711     return Target.multiVersionSortPriority(LHS.substr(1)) >
1712            Target.multiVersionSortPriority(RHS.substr(1));
1713   });
1714 
1715   bool IsFirst = true;
1716 
1717   if (!Info.CPU.empty()) {
1718     IsFirst = false;
1719     Out << "arch_" << Info.CPU;
1720   }
1721 
1722   for (StringRef Feat : Info.Features) {
1723     if (!IsFirst)
1724       Out << '_';
1725     IsFirst = false;
1726     Out << Feat.substr(1);
1727   }
1728 }
1729 
1730 // Returns true if GD is a function decl with internal linkage and
1731 // needs a unique suffix after the mangled name.
1732 static bool isUniqueInternalLinkageDecl(GlobalDecl GD,
1733                                         CodeGenModule &CGM) {
1734   const Decl *D = GD.getDecl();
1735   return !CGM.getModuleNameHash().empty() && isa<FunctionDecl>(D) &&
1736          (CGM.getFunctionLinkage(GD) == llvm::GlobalValue::InternalLinkage);
1737 }
1738 
1739 static void AppendTargetClonesMangling(const CodeGenModule &CGM,
1740                                        const TargetClonesAttr *Attr,
1741                                        unsigned VersionIndex,
1742                                        raw_ostream &Out) {
1743   const TargetInfo &TI = CGM.getTarget();
1744   if (TI.getTriple().isAArch64()) {
1745     StringRef FeatureStr = Attr->getFeatureStr(VersionIndex);
1746     if (FeatureStr == "default")
1747       return;
1748     Out << "._";
1749     SmallVector<StringRef, 8> Features;
1750     FeatureStr.split(Features, "+");
1751     llvm::stable_sort(Features,
1752                       [&TI](const StringRef FeatL, const StringRef FeatR) {
1753                         return TI.multiVersionSortPriority(FeatL) <
1754                                TI.multiVersionSortPriority(FeatR);
1755                       });
1756     for (auto &Feat : Features) {
1757       Out << 'M';
1758       Out << Feat;
1759     }
1760   } else {
1761     Out << '.';
1762     StringRef FeatureStr = Attr->getFeatureStr(VersionIndex);
1763     if (FeatureStr.startswith("arch="))
1764       Out << "arch_" << FeatureStr.substr(sizeof("arch=") - 1);
1765     else
1766       Out << FeatureStr;
1767 
1768     Out << '.' << Attr->getMangledIndex(VersionIndex);
1769   }
1770 }
1771 
1772 static std::string getMangledNameImpl(CodeGenModule &CGM, GlobalDecl GD,
1773                                       const NamedDecl *ND,
1774                                       bool OmitMultiVersionMangling = false) {
1775   SmallString<256> Buffer;
1776   llvm::raw_svector_ostream Out(Buffer);
1777   MangleContext &MC = CGM.getCXXABI().getMangleContext();
1778   if (!CGM.getModuleNameHash().empty())
1779     MC.needsUniqueInternalLinkageNames();
1780   bool ShouldMangle = MC.shouldMangleDeclName(ND);
1781   if (ShouldMangle)
1782     MC.mangleName(GD.getWithDecl(ND), Out);
1783   else {
1784     IdentifierInfo *II = ND->getIdentifier();
1785     assert(II && "Attempt to mangle unnamed decl.");
1786     const auto *FD = dyn_cast<FunctionDecl>(ND);
1787 
1788     if (FD &&
1789         FD->getType()->castAs<FunctionType>()->getCallConv() == CC_X86RegCall) {
1790       if (CGM.getLangOpts().RegCall4)
1791         Out << "__regcall4__" << II->getName();
1792       else
1793         Out << "__regcall3__" << II->getName();
1794     } else if (FD && FD->hasAttr<CUDAGlobalAttr>() &&
1795                GD.getKernelReferenceKind() == KernelReferenceKind::Stub) {
1796       Out << "__device_stub__" << II->getName();
1797     } else {
1798       Out << II->getName();
1799     }
1800   }
1801 
1802   // Check if the module name hash should be appended for internal linkage
1803   // symbols.   This should come before multi-version target suffixes are
1804   // appended. This is to keep the name and module hash suffix of the
1805   // internal linkage function together.  The unique suffix should only be
1806   // added when name mangling is done to make sure that the final name can
1807   // be properly demangled.  For example, for C functions without prototypes,
1808   // name mangling is not done and the unique suffix should not be appeneded
1809   // then.
1810   if (ShouldMangle && isUniqueInternalLinkageDecl(GD, CGM)) {
1811     assert(CGM.getCodeGenOpts().UniqueInternalLinkageNames &&
1812            "Hash computed when not explicitly requested");
1813     Out << CGM.getModuleNameHash();
1814   }
1815 
1816   if (const auto *FD = dyn_cast<FunctionDecl>(ND))
1817     if (FD->isMultiVersion() && !OmitMultiVersionMangling) {
1818       switch (FD->getMultiVersionKind()) {
1819       case MultiVersionKind::CPUDispatch:
1820       case MultiVersionKind::CPUSpecific:
1821         AppendCPUSpecificCPUDispatchMangling(CGM,
1822                                              FD->getAttr<CPUSpecificAttr>(),
1823                                              GD.getMultiVersionIndex(), Out);
1824         break;
1825       case MultiVersionKind::Target:
1826         AppendTargetMangling(CGM, FD->getAttr<TargetAttr>(), Out);
1827         break;
1828       case MultiVersionKind::TargetVersion:
1829         AppendTargetVersionMangling(CGM, FD->getAttr<TargetVersionAttr>(), Out);
1830         break;
1831       case MultiVersionKind::TargetClones:
1832         AppendTargetClonesMangling(CGM, FD->getAttr<TargetClonesAttr>(),
1833                                    GD.getMultiVersionIndex(), Out);
1834         break;
1835       case MultiVersionKind::None:
1836         llvm_unreachable("None multiversion type isn't valid here");
1837       }
1838     }
1839 
1840   // Make unique name for device side static file-scope variable for HIP.
1841   if (CGM.getContext().shouldExternalize(ND) &&
1842       CGM.getLangOpts().GPURelocatableDeviceCode &&
1843       CGM.getLangOpts().CUDAIsDevice)
1844     CGM.printPostfixForExternalizedDecl(Out, ND);
1845 
1846   return std::string(Out.str());
1847 }
1848 
1849 void CodeGenModule::UpdateMultiVersionNames(GlobalDecl GD,
1850                                             const FunctionDecl *FD,
1851                                             StringRef &CurName) {
1852   if (!FD->isMultiVersion())
1853     return;
1854 
1855   // Get the name of what this would be without the 'target' attribute.  This
1856   // allows us to lookup the version that was emitted when this wasn't a
1857   // multiversion function.
1858   std::string NonTargetName =
1859       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
1860   GlobalDecl OtherGD;
1861   if (lookupRepresentativeDecl(NonTargetName, OtherGD)) {
1862     assert(OtherGD.getCanonicalDecl()
1863                .getDecl()
1864                ->getAsFunction()
1865                ->isMultiVersion() &&
1866            "Other GD should now be a multiversioned function");
1867     // OtherFD is the version of this function that was mangled BEFORE
1868     // becoming a MultiVersion function.  It potentially needs to be updated.
1869     const FunctionDecl *OtherFD = OtherGD.getCanonicalDecl()
1870                                       .getDecl()
1871                                       ->getAsFunction()
1872                                       ->getMostRecentDecl();
1873     std::string OtherName = getMangledNameImpl(*this, OtherGD, OtherFD);
1874     // This is so that if the initial version was already the 'default'
1875     // version, we don't try to update it.
1876     if (OtherName != NonTargetName) {
1877       // Remove instead of erase, since others may have stored the StringRef
1878       // to this.
1879       const auto ExistingRecord = Manglings.find(NonTargetName);
1880       if (ExistingRecord != std::end(Manglings))
1881         Manglings.remove(&(*ExistingRecord));
1882       auto Result = Manglings.insert(std::make_pair(OtherName, OtherGD));
1883       StringRef OtherNameRef = MangledDeclNames[OtherGD.getCanonicalDecl()] =
1884           Result.first->first();
1885       // If this is the current decl is being created, make sure we update the name.
1886       if (GD.getCanonicalDecl() == OtherGD.getCanonicalDecl())
1887         CurName = OtherNameRef;
1888       if (llvm::GlobalValue *Entry = GetGlobalValue(NonTargetName))
1889         Entry->setName(OtherName);
1890     }
1891   }
1892 }
1893 
1894 StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
1895   GlobalDecl CanonicalGD = GD.getCanonicalDecl();
1896 
1897   // Some ABIs don't have constructor variants.  Make sure that base and
1898   // complete constructors get mangled the same.
1899   if (const auto *CD = dyn_cast<CXXConstructorDecl>(CanonicalGD.getDecl())) {
1900     if (!getTarget().getCXXABI().hasConstructorVariants()) {
1901       CXXCtorType OrigCtorType = GD.getCtorType();
1902       assert(OrigCtorType == Ctor_Base || OrigCtorType == Ctor_Complete);
1903       if (OrigCtorType == Ctor_Base)
1904         CanonicalGD = GlobalDecl(CD, Ctor_Complete);
1905     }
1906   }
1907 
1908   // In CUDA/HIP device compilation with -fgpu-rdc, the mangled name of a
1909   // static device variable depends on whether the variable is referenced by
1910   // a host or device host function. Therefore the mangled name cannot be
1911   // cached.
1912   if (!LangOpts.CUDAIsDevice || !getContext().mayExternalize(GD.getDecl())) {
1913     auto FoundName = MangledDeclNames.find(CanonicalGD);
1914     if (FoundName != MangledDeclNames.end())
1915       return FoundName->second;
1916   }
1917 
1918   // Keep the first result in the case of a mangling collision.
1919   const auto *ND = cast<NamedDecl>(GD.getDecl());
1920   std::string MangledName = getMangledNameImpl(*this, GD, ND);
1921 
1922   // Ensure either we have different ABIs between host and device compilations,
1923   // says host compilation following MSVC ABI but device compilation follows
1924   // Itanium C++ ABI or, if they follow the same ABI, kernel names after
1925   // mangling should be the same after name stubbing. The later checking is
1926   // very important as the device kernel name being mangled in host-compilation
1927   // is used to resolve the device binaries to be executed. Inconsistent naming
1928   // result in undefined behavior. Even though we cannot check that naming
1929   // directly between host- and device-compilations, the host- and
1930   // device-mangling in host compilation could help catching certain ones.
1931   assert(!isa<FunctionDecl>(ND) || !ND->hasAttr<CUDAGlobalAttr>() ||
1932          getContext().shouldExternalize(ND) || getLangOpts().CUDAIsDevice ||
1933          (getContext().getAuxTargetInfo() &&
1934           (getContext().getAuxTargetInfo()->getCXXABI() !=
1935            getContext().getTargetInfo().getCXXABI())) ||
1936          getCUDARuntime().getDeviceSideName(ND) ==
1937              getMangledNameImpl(
1938                  *this,
1939                  GD.getWithKernelReferenceKind(KernelReferenceKind::Kernel),
1940                  ND));
1941 
1942   auto Result = Manglings.insert(std::make_pair(MangledName, GD));
1943   return MangledDeclNames[CanonicalGD] = Result.first->first();
1944 }
1945 
1946 StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
1947                                              const BlockDecl *BD) {
1948   MangleContext &MangleCtx = getCXXABI().getMangleContext();
1949   const Decl *D = GD.getDecl();
1950 
1951   SmallString<256> Buffer;
1952   llvm::raw_svector_ostream Out(Buffer);
1953   if (!D)
1954     MangleCtx.mangleGlobalBlock(BD,
1955       dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl()), Out);
1956   else if (const auto *CD = dyn_cast<CXXConstructorDecl>(D))
1957     MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Out);
1958   else if (const auto *DD = dyn_cast<CXXDestructorDecl>(D))
1959     MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Out);
1960   else
1961     MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out);
1962 
1963   auto Result = Manglings.insert(std::make_pair(Out.str(), BD));
1964   return Result.first->first();
1965 }
1966 
1967 const GlobalDecl CodeGenModule::getMangledNameDecl(StringRef Name) {
1968   auto it = MangledDeclNames.begin();
1969   while (it != MangledDeclNames.end()) {
1970     if (it->second == Name)
1971       return it->first;
1972     it++;
1973   }
1974   return GlobalDecl();
1975 }
1976 
1977 llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) {
1978   return getModule().getNamedValue(Name);
1979 }
1980 
1981 /// AddGlobalCtor - Add a function to the list that will be called before
1982 /// main() runs.
1983 void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority,
1984                                   unsigned LexOrder,
1985                                   llvm::Constant *AssociatedData) {
1986   // FIXME: Type coercion of void()* types.
1987   GlobalCtors.push_back(Structor(Priority, LexOrder, Ctor, AssociatedData));
1988 }
1989 
1990 /// AddGlobalDtor - Add a function to the list that will be called
1991 /// when the module is unloaded.
1992 void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority,
1993                                   bool IsDtorAttrFunc) {
1994   if (CodeGenOpts.RegisterGlobalDtorsWithAtExit &&
1995       (!getContext().getTargetInfo().getTriple().isOSAIX() || IsDtorAttrFunc)) {
1996     DtorsUsingAtExit[Priority].push_back(Dtor);
1997     return;
1998   }
1999 
2000   // FIXME: Type coercion of void()* types.
2001   GlobalDtors.push_back(Structor(Priority, ~0U, Dtor, nullptr));
2002 }
2003 
2004 void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
2005   if (Fns.empty()) return;
2006 
2007   // Ctor function type is void()*.
2008   llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false);
2009   llvm::Type *CtorPFTy = llvm::PointerType::get(CtorFTy,
2010       TheModule.getDataLayout().getProgramAddressSpace());
2011 
2012   // Get the type of a ctor entry, { i32, void ()*, i8* }.
2013   llvm::StructType *CtorStructTy = llvm::StructType::get(
2014       Int32Ty, CtorPFTy, VoidPtrTy);
2015 
2016   // Construct the constructor and destructor arrays.
2017   ConstantInitBuilder builder(*this);
2018   auto ctors = builder.beginArray(CtorStructTy);
2019   for (const auto &I : Fns) {
2020     auto ctor = ctors.beginStruct(CtorStructTy);
2021     ctor.addInt(Int32Ty, I.Priority);
2022     ctor.add(I.Initializer);
2023     if (I.AssociatedData)
2024       ctor.add(I.AssociatedData);
2025     else
2026       ctor.addNullPointer(VoidPtrTy);
2027     ctor.finishAndAddTo(ctors);
2028   }
2029 
2030   auto list =
2031     ctors.finishAndCreateGlobal(GlobalName, getPointerAlign(),
2032                                 /*constant*/ false,
2033                                 llvm::GlobalValue::AppendingLinkage);
2034 
2035   // The LTO linker doesn't seem to like it when we set an alignment
2036   // on appending variables.  Take it off as a workaround.
2037   list->setAlignment(std::nullopt);
2038 
2039   Fns.clear();
2040 }
2041 
2042 llvm::GlobalValue::LinkageTypes
2043 CodeGenModule::getFunctionLinkage(GlobalDecl GD) {
2044   const auto *D = cast<FunctionDecl>(GD.getDecl());
2045 
2046   GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);
2047 
2048   if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(D))
2049     return getCXXABI().getCXXDestructorLinkage(Linkage, Dtor, GD.getDtorType());
2050 
2051   return getLLVMLinkageForDeclarator(D, Linkage);
2052 }
2053 
2054 llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
2055   llvm::MDString *MDS = dyn_cast<llvm::MDString>(MD);
2056   if (!MDS) return nullptr;
2057 
2058   return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
2059 }
2060 
2061 llvm::ConstantInt *CodeGenModule::CreateKCFITypeId(QualType T) {
2062   if (auto *FnType = T->getAs<FunctionProtoType>())
2063     T = getContext().getFunctionType(
2064         FnType->getReturnType(), FnType->getParamTypes(),
2065         FnType->getExtProtoInfo().withExceptionSpec(EST_None));
2066 
2067   std::string OutName;
2068   llvm::raw_string_ostream Out(OutName);
2069   getCXXABI().getMangleContext().mangleCanonicalTypeName(
2070       T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
2071 
2072   if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
2073     Out << ".normalized";
2074 
2075   return llvm::ConstantInt::get(Int32Ty,
2076                                 static_cast<uint32_t>(llvm::xxHash64(OutName)));
2077 }
2078 
2079 void CodeGenModule::SetLLVMFunctionAttributes(GlobalDecl GD,
2080                                               const CGFunctionInfo &Info,
2081                                               llvm::Function *F, bool IsThunk) {
2082   unsigned CallingConv;
2083   llvm::AttributeList PAL;
2084   ConstructAttributeList(F->getName(), Info, GD, PAL, CallingConv,
2085                          /*AttrOnCallSite=*/false, IsThunk);
2086   F->setAttributes(PAL);
2087   F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
2088 }
2089 
2090 static void removeImageAccessQualifier(std::string& TyName) {
2091   std::string ReadOnlyQual("__read_only");
2092   std::string::size_type ReadOnlyPos = TyName.find(ReadOnlyQual);
2093   if (ReadOnlyPos != std::string::npos)
2094     // "+ 1" for the space after access qualifier.
2095     TyName.erase(ReadOnlyPos, ReadOnlyQual.size() + 1);
2096   else {
2097     std::string WriteOnlyQual("__write_only");
2098     std::string::size_type WriteOnlyPos = TyName.find(WriteOnlyQual);
2099     if (WriteOnlyPos != std::string::npos)
2100       TyName.erase(WriteOnlyPos, WriteOnlyQual.size() + 1);
2101     else {
2102       std::string ReadWriteQual("__read_write");
2103       std::string::size_type ReadWritePos = TyName.find(ReadWriteQual);
2104       if (ReadWritePos != std::string::npos)
2105         TyName.erase(ReadWritePos, ReadWriteQual.size() + 1);
2106     }
2107   }
2108 }
2109 
2110 // Returns the address space id that should be produced to the
2111 // kernel_arg_addr_space metadata. This is always fixed to the ids
2112 // as specified in the SPIR 2.0 specification in order to differentiate
2113 // for example in clGetKernelArgInfo() implementation between the address
2114 // spaces with targets without unique mapping to the OpenCL address spaces
2115 // (basically all single AS CPUs).
2116 static unsigned ArgInfoAddressSpace(LangAS AS) {
2117   switch (AS) {
2118   case LangAS::opencl_global:
2119     return 1;
2120   case LangAS::opencl_constant:
2121     return 2;
2122   case LangAS::opencl_local:
2123     return 3;
2124   case LangAS::opencl_generic:
2125     return 4; // Not in SPIR 2.0 specs.
2126   case LangAS::opencl_global_device:
2127     return 5;
2128   case LangAS::opencl_global_host:
2129     return 6;
2130   default:
2131     return 0; // Assume private.
2132   }
2133 }
2134 
2135 void CodeGenModule::GenKernelArgMetadata(llvm::Function *Fn,
2136                                          const FunctionDecl *FD,
2137                                          CodeGenFunction *CGF) {
2138   assert(((FD && CGF) || (!FD && !CGF)) &&
2139          "Incorrect use - FD and CGF should either be both null or not!");
2140   // Create MDNodes that represent the kernel arg metadata.
2141   // Each MDNode is a list in the form of "key", N number of values which is
2142   // the same number of values as their are kernel arguments.
2143 
2144   const PrintingPolicy &Policy = Context.getPrintingPolicy();
2145 
2146   // MDNode for the kernel argument address space qualifiers.
2147   SmallVector<llvm::Metadata *, 8> addressQuals;
2148 
2149   // MDNode for the kernel argument access qualifiers (images only).
2150   SmallVector<llvm::Metadata *, 8> accessQuals;
2151 
2152   // MDNode for the kernel argument type names.
2153   SmallVector<llvm::Metadata *, 8> argTypeNames;
2154 
2155   // MDNode for the kernel argument base type names.
2156   SmallVector<llvm::Metadata *, 8> argBaseTypeNames;
2157 
2158   // MDNode for the kernel argument type qualifiers.
2159   SmallVector<llvm::Metadata *, 8> argTypeQuals;
2160 
2161   // MDNode for the kernel argument names.
2162   SmallVector<llvm::Metadata *, 8> argNames;
2163 
2164   if (FD && CGF)
2165     for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
2166       const ParmVarDecl *parm = FD->getParamDecl(i);
2167       // Get argument name.
2168       argNames.push_back(llvm::MDString::get(VMContext, parm->getName()));
2169 
2170       if (!getLangOpts().OpenCL)
2171         continue;
2172       QualType ty = parm->getType();
2173       std::string typeQuals;
2174 
2175       // Get image and pipe access qualifier:
2176       if (ty->isImageType() || ty->isPipeType()) {
2177         const Decl *PDecl = parm;
2178         if (const auto *TD = ty->getAs<TypedefType>())
2179           PDecl = TD->getDecl();
2180         const OpenCLAccessAttr *A = PDecl->getAttr<OpenCLAccessAttr>();
2181         if (A && A->isWriteOnly())
2182           accessQuals.push_back(llvm::MDString::get(VMContext, "write_only"));
2183         else if (A && A->isReadWrite())
2184           accessQuals.push_back(llvm::MDString::get(VMContext, "read_write"));
2185         else
2186           accessQuals.push_back(llvm::MDString::get(VMContext, "read_only"));
2187       } else
2188         accessQuals.push_back(llvm::MDString::get(VMContext, "none"));
2189 
2190       auto getTypeSpelling = [&](QualType Ty) {
2191         auto typeName = Ty.getUnqualifiedType().getAsString(Policy);
2192 
2193         if (Ty.isCanonical()) {
2194           StringRef typeNameRef = typeName;
2195           // Turn "unsigned type" to "utype"
2196           if (typeNameRef.consume_front("unsigned "))
2197             return std::string("u") + typeNameRef.str();
2198           if (typeNameRef.consume_front("signed "))
2199             return typeNameRef.str();
2200         }
2201 
2202         return typeName;
2203       };
2204 
2205       if (ty->isPointerType()) {
2206         QualType pointeeTy = ty->getPointeeType();
2207 
2208         // Get address qualifier.
2209         addressQuals.push_back(
2210             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(
2211                 ArgInfoAddressSpace(pointeeTy.getAddressSpace()))));
2212 
2213         // Get argument type name.
2214         std::string typeName = getTypeSpelling(pointeeTy) + "*";
2215         std::string baseTypeName =
2216             getTypeSpelling(pointeeTy.getCanonicalType()) + "*";
2217         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
2218         argBaseTypeNames.push_back(
2219             llvm::MDString::get(VMContext, baseTypeName));
2220 
2221         // Get argument type qualifiers:
2222         if (ty.isRestrictQualified())
2223           typeQuals = "restrict";
2224         if (pointeeTy.isConstQualified() ||
2225             (pointeeTy.getAddressSpace() == LangAS::opencl_constant))
2226           typeQuals += typeQuals.empty() ? "const" : " const";
2227         if (pointeeTy.isVolatileQualified())
2228           typeQuals += typeQuals.empty() ? "volatile" : " volatile";
2229       } else {
2230         uint32_t AddrSpc = 0;
2231         bool isPipe = ty->isPipeType();
2232         if (ty->isImageType() || isPipe)
2233           AddrSpc = ArgInfoAddressSpace(LangAS::opencl_global);
2234 
2235         addressQuals.push_back(
2236             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(AddrSpc)));
2237 
2238         // Get argument type name.
2239         ty = isPipe ? ty->castAs<PipeType>()->getElementType() : ty;
2240         std::string typeName = getTypeSpelling(ty);
2241         std::string baseTypeName = getTypeSpelling(ty.getCanonicalType());
2242 
2243         // Remove access qualifiers on images
2244         // (as they are inseparable from type in clang implementation,
2245         // but OpenCL spec provides a special query to get access qualifier
2246         // via clGetKernelArgInfo with CL_KERNEL_ARG_ACCESS_QUALIFIER):
2247         if (ty->isImageType()) {
2248           removeImageAccessQualifier(typeName);
2249           removeImageAccessQualifier(baseTypeName);
2250         }
2251 
2252         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
2253         argBaseTypeNames.push_back(
2254             llvm::MDString::get(VMContext, baseTypeName));
2255 
2256         if (isPipe)
2257           typeQuals = "pipe";
2258       }
2259       argTypeQuals.push_back(llvm::MDString::get(VMContext, typeQuals));
2260     }
2261 
2262   if (getLangOpts().OpenCL) {
2263     Fn->setMetadata("kernel_arg_addr_space",
2264                     llvm::MDNode::get(VMContext, addressQuals));
2265     Fn->setMetadata("kernel_arg_access_qual",
2266                     llvm::MDNode::get(VMContext, accessQuals));
2267     Fn->setMetadata("kernel_arg_type",
2268                     llvm::MDNode::get(VMContext, argTypeNames));
2269     Fn->setMetadata("kernel_arg_base_type",
2270                     llvm::MDNode::get(VMContext, argBaseTypeNames));
2271     Fn->setMetadata("kernel_arg_type_qual",
2272                     llvm::MDNode::get(VMContext, argTypeQuals));
2273   }
2274   if (getCodeGenOpts().EmitOpenCLArgMetadata ||
2275       getCodeGenOpts().HIPSaveKernelArgName)
2276     Fn->setMetadata("kernel_arg_name",
2277                     llvm::MDNode::get(VMContext, argNames));
2278 }
2279 
2280 /// Determines whether the language options require us to model
2281 /// unwind exceptions.  We treat -fexceptions as mandating this
2282 /// except under the fragile ObjC ABI with only ObjC exceptions
2283 /// enabled.  This means, for example, that C with -fexceptions
2284 /// enables this.
2285 static bool hasUnwindExceptions(const LangOptions &LangOpts) {
2286   // If exceptions are completely disabled, obviously this is false.
2287   if (!LangOpts.Exceptions) return false;
2288 
2289   // If C++ exceptions are enabled, this is true.
2290   if (LangOpts.CXXExceptions) return true;
2291 
2292   // If ObjC exceptions are enabled, this depends on the ABI.
2293   if (LangOpts.ObjCExceptions) {
2294     return LangOpts.ObjCRuntime.hasUnwindExceptions();
2295   }
2296 
2297   return true;
2298 }
2299 
2300 static bool requiresMemberFunctionPointerTypeMetadata(CodeGenModule &CGM,
2301                                                       const CXXMethodDecl *MD) {
2302   // Check that the type metadata can ever actually be used by a call.
2303   if (!CGM.getCodeGenOpts().LTOUnit ||
2304       !CGM.HasHiddenLTOVisibility(MD->getParent()))
2305     return false;
2306 
2307   // Only functions whose address can be taken with a member function pointer
2308   // need this sort of type metadata.
2309   return MD->isImplicitObjectMemberFunction() && !MD->isVirtual() &&
2310          !isa<CXXConstructorDecl, CXXDestructorDecl>(MD);
2311 }
2312 
2313 SmallVector<const CXXRecordDecl *, 0>
2314 CodeGenModule::getMostBaseClasses(const CXXRecordDecl *RD) {
2315   llvm::SetVector<const CXXRecordDecl *> MostBases;
2316 
2317   std::function<void (const CXXRecordDecl *)> CollectMostBases;
2318   CollectMostBases = [&](const CXXRecordDecl *RD) {
2319     if (RD->getNumBases() == 0)
2320       MostBases.insert(RD);
2321     for (const CXXBaseSpecifier &B : RD->bases())
2322       CollectMostBases(B.getType()->getAsCXXRecordDecl());
2323   };
2324   CollectMostBases(RD);
2325   return MostBases.takeVector();
2326 }
2327 
2328 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
2329                                                            llvm::Function *F) {
2330   llvm::AttrBuilder B(F->getContext());
2331 
2332   if ((!D || !D->hasAttr<NoUwtableAttr>()) && CodeGenOpts.UnwindTables)
2333     B.addUWTableAttr(llvm::UWTableKind(CodeGenOpts.UnwindTables));
2334 
2335   if (CodeGenOpts.StackClashProtector)
2336     B.addAttribute("probe-stack", "inline-asm");
2337 
2338   if (!hasUnwindExceptions(LangOpts))
2339     B.addAttribute(llvm::Attribute::NoUnwind);
2340 
2341   if (D && D->hasAttr<NoStackProtectorAttr>())
2342     ; // Do nothing.
2343   else if (D && D->hasAttr<StrictGuardStackCheckAttr>() &&
2344            isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPOn))
2345     B.addAttribute(llvm::Attribute::StackProtectStrong);
2346   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPOn))
2347     B.addAttribute(llvm::Attribute::StackProtect);
2348   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPStrong))
2349     B.addAttribute(llvm::Attribute::StackProtectStrong);
2350   else if (isStackProtectorOn(LangOpts, getTriple(), LangOptions::SSPReq))
2351     B.addAttribute(llvm::Attribute::StackProtectReq);
2352 
2353   if (!D) {
2354     // If we don't have a declaration to control inlining, the function isn't
2355     // explicitly marked as alwaysinline for semantic reasons, and inlining is
2356     // disabled, mark the function as noinline.
2357     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline) &&
2358         CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining)
2359       B.addAttribute(llvm::Attribute::NoInline);
2360 
2361     F->addFnAttrs(B);
2362     return;
2363   }
2364 
2365   // Handle SME attributes that apply to function definitions,
2366   // rather than to function prototypes.
2367   if (D->hasAttr<ArmLocallyStreamingAttr>())
2368     B.addAttribute("aarch64_pstate_sm_body");
2369 
2370   if (D->hasAttr<ArmNewZAAttr>())
2371     B.addAttribute("aarch64_pstate_za_new");
2372 
2373   // Track whether we need to add the optnone LLVM attribute,
2374   // starting with the default for this optimization level.
2375   bool ShouldAddOptNone =
2376       !CodeGenOpts.DisableO0ImplyOptNone && CodeGenOpts.OptimizationLevel == 0;
2377   // We can't add optnone in the following cases, it won't pass the verifier.
2378   ShouldAddOptNone &= !D->hasAttr<MinSizeAttr>();
2379   ShouldAddOptNone &= !D->hasAttr<AlwaysInlineAttr>();
2380 
2381   // Add optnone, but do so only if the function isn't always_inline.
2382   if ((ShouldAddOptNone || D->hasAttr<OptimizeNoneAttr>()) &&
2383       !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2384     B.addAttribute(llvm::Attribute::OptimizeNone);
2385 
2386     // OptimizeNone implies noinline; we should not be inlining such functions.
2387     B.addAttribute(llvm::Attribute::NoInline);
2388 
2389     // We still need to handle naked functions even though optnone subsumes
2390     // much of their semantics.
2391     if (D->hasAttr<NakedAttr>())
2392       B.addAttribute(llvm::Attribute::Naked);
2393 
2394     // OptimizeNone wins over OptimizeForSize and MinSize.
2395     F->removeFnAttr(llvm::Attribute::OptimizeForSize);
2396     F->removeFnAttr(llvm::Attribute::MinSize);
2397   } else if (D->hasAttr<NakedAttr>()) {
2398     // Naked implies noinline: we should not be inlining such functions.
2399     B.addAttribute(llvm::Attribute::Naked);
2400     B.addAttribute(llvm::Attribute::NoInline);
2401   } else if (D->hasAttr<NoDuplicateAttr>()) {
2402     B.addAttribute(llvm::Attribute::NoDuplicate);
2403   } else if (D->hasAttr<NoInlineAttr>() && !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2404     // Add noinline if the function isn't always_inline.
2405     B.addAttribute(llvm::Attribute::NoInline);
2406   } else if (D->hasAttr<AlwaysInlineAttr>() &&
2407              !F->hasFnAttribute(llvm::Attribute::NoInline)) {
2408     // (noinline wins over always_inline, and we can't specify both in IR)
2409     B.addAttribute(llvm::Attribute::AlwaysInline);
2410   } else if (CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining) {
2411     // If we're not inlining, then force everything that isn't always_inline to
2412     // carry an explicit noinline attribute.
2413     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline))
2414       B.addAttribute(llvm::Attribute::NoInline);
2415   } else {
2416     // Otherwise, propagate the inline hint attribute and potentially use its
2417     // absence to mark things as noinline.
2418     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
2419       // Search function and template pattern redeclarations for inline.
2420       auto CheckForInline = [](const FunctionDecl *FD) {
2421         auto CheckRedeclForInline = [](const FunctionDecl *Redecl) {
2422           return Redecl->isInlineSpecified();
2423         };
2424         if (any_of(FD->redecls(), CheckRedeclForInline))
2425           return true;
2426         const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern();
2427         if (!Pattern)
2428           return false;
2429         return any_of(Pattern->redecls(), CheckRedeclForInline);
2430       };
2431       if (CheckForInline(FD)) {
2432         B.addAttribute(llvm::Attribute::InlineHint);
2433       } else if (CodeGenOpts.getInlining() ==
2434                      CodeGenOptions::OnlyHintInlining &&
2435                  !FD->isInlined() &&
2436                  !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
2437         B.addAttribute(llvm::Attribute::NoInline);
2438       }
2439     }
2440   }
2441 
2442   // Add other optimization related attributes if we are optimizing this
2443   // function.
2444   if (!D->hasAttr<OptimizeNoneAttr>()) {
2445     if (D->hasAttr<ColdAttr>()) {
2446       if (!ShouldAddOptNone)
2447         B.addAttribute(llvm::Attribute::OptimizeForSize);
2448       B.addAttribute(llvm::Attribute::Cold);
2449     }
2450     if (D->hasAttr<HotAttr>())
2451       B.addAttribute(llvm::Attribute::Hot);
2452     if (D->hasAttr<MinSizeAttr>())
2453       B.addAttribute(llvm::Attribute::MinSize);
2454   }
2455 
2456   F->addFnAttrs(B);
2457 
2458   unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
2459   if (alignment)
2460     F->setAlignment(llvm::Align(alignment));
2461 
2462   if (!D->hasAttr<AlignedAttr>())
2463     if (LangOpts.FunctionAlignment)
2464       F->setAlignment(llvm::Align(1ull << LangOpts.FunctionAlignment));
2465 
2466   // Some C++ ABIs require 2-byte alignment for member functions, in order to
2467   // reserve a bit for differentiating between virtual and non-virtual member
2468   // functions. If the current target's C++ ABI requires this and this is a
2469   // member function, set its alignment accordingly.
2470   if (getTarget().getCXXABI().areMemberFunctionsAligned()) {
2471     if (isa<CXXMethodDecl>(D) && F->getPointerAlignment(getDataLayout()) < 2)
2472       F->setAlignment(std::max(llvm::Align(2), F->getAlign().valueOrOne()));
2473   }
2474 
2475   // In the cross-dso CFI mode with canonical jump tables, we want !type
2476   // attributes on definitions only.
2477   if (CodeGenOpts.SanitizeCfiCrossDso &&
2478       CodeGenOpts.SanitizeCfiCanonicalJumpTables) {
2479     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
2480       // Skip available_externally functions. They won't be codegen'ed in the
2481       // current module anyway.
2482       if (getContext().GetGVALinkageForFunction(FD) != GVA_AvailableExternally)
2483         CreateFunctionTypeMetadataForIcall(FD, F);
2484     }
2485   }
2486 
2487   // Emit type metadata on member functions for member function pointer checks.
2488   // These are only ever necessary on definitions; we're guaranteed that the
2489   // definition will be present in the LTO unit as a result of LTO visibility.
2490   auto *MD = dyn_cast<CXXMethodDecl>(D);
2491   if (MD && requiresMemberFunctionPointerTypeMetadata(*this, MD)) {
2492     for (const CXXRecordDecl *Base : getMostBaseClasses(MD->getParent())) {
2493       llvm::Metadata *Id =
2494           CreateMetadataIdentifierForType(Context.getMemberPointerType(
2495               MD->getType(), Context.getRecordType(Base).getTypePtr()));
2496       F->addTypeMetadata(0, Id);
2497     }
2498   }
2499 }
2500 
2501 void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
2502   const Decl *D = GD.getDecl();
2503   if (isa_and_nonnull<NamedDecl>(D))
2504     setGVProperties(GV, GD);
2505   else
2506     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
2507 
2508   if (D && D->hasAttr<UsedAttr>())
2509     addUsedOrCompilerUsedGlobal(GV);
2510 
2511   if (const auto *VD = dyn_cast_if_present<VarDecl>(D);
2512       VD &&
2513       ((CodeGenOpts.KeepPersistentStorageVariables &&
2514         (VD->getStorageDuration() == SD_Static ||
2515          VD->getStorageDuration() == SD_Thread)) ||
2516        (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
2517         VD->getType().isConstQualified())))
2518     addUsedOrCompilerUsedGlobal(GV);
2519 }
2520 
2521 bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
2522                                                 llvm::AttrBuilder &Attrs,
2523                                                 bool SetTargetFeatures) {
2524   // Add target-cpu and target-features attributes to functions. If
2525   // we have a decl for the function and it has a target attribute then
2526   // parse that and add it to the feature set.
2527   StringRef TargetCPU = getTarget().getTargetOpts().CPU;
2528   StringRef TuneCPU = getTarget().getTargetOpts().TuneCPU;
2529   std::vector<std::string> Features;
2530   const auto *FD = dyn_cast_or_null<FunctionDecl>(GD.getDecl());
2531   FD = FD ? FD->getMostRecentDecl() : FD;
2532   const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
2533   const auto *TV = FD ? FD->getAttr<TargetVersionAttr>() : nullptr;
2534   assert((!TD || !TV) && "both target_version and target specified");
2535   const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
2536   const auto *TC = FD ? FD->getAttr<TargetClonesAttr>() : nullptr;
2537   bool AddedAttr = false;
2538   if (TD || TV || SD || TC) {
2539     llvm::StringMap<bool> FeatureMap;
2540     getContext().getFunctionFeatureMap(FeatureMap, GD);
2541 
2542     // Produce the canonical string for this set of features.
2543     for (const llvm::StringMap<bool>::value_type &Entry : FeatureMap)
2544       Features.push_back((Entry.getValue() ? "+" : "-") + Entry.getKey().str());
2545 
2546     // Now add the target-cpu and target-features to the function.
2547     // While we populated the feature map above, we still need to
2548     // get and parse the target attribute so we can get the cpu for
2549     // the function.
2550     if (TD) {
2551       ParsedTargetAttr ParsedAttr =
2552           Target.parseTargetAttr(TD->getFeaturesStr());
2553       if (!ParsedAttr.CPU.empty() &&
2554           getTarget().isValidCPUName(ParsedAttr.CPU)) {
2555         TargetCPU = ParsedAttr.CPU;
2556         TuneCPU = ""; // Clear the tune CPU.
2557       }
2558       if (!ParsedAttr.Tune.empty() &&
2559           getTarget().isValidCPUName(ParsedAttr.Tune))
2560         TuneCPU = ParsedAttr.Tune;
2561     }
2562 
2563     if (SD) {
2564       // Apply the given CPU name as the 'tune-cpu' so that the optimizer can
2565       // favor this processor.
2566       TuneCPU = SD->getCPUName(GD.getMultiVersionIndex())->getName();
2567     }
2568   } else {
2569     // Otherwise just add the existing target cpu and target features to the
2570     // function.
2571     Features = getTarget().getTargetOpts().Features;
2572   }
2573 
2574   if (!TargetCPU.empty()) {
2575     Attrs.addAttribute("target-cpu", TargetCPU);
2576     AddedAttr = true;
2577   }
2578   if (!TuneCPU.empty()) {
2579     Attrs.addAttribute("tune-cpu", TuneCPU);
2580     AddedAttr = true;
2581   }
2582   if (!Features.empty() && SetTargetFeatures) {
2583     llvm::erase_if(Features, [&](const std::string& F) {
2584        return getTarget().isReadOnlyFeature(F.substr(1));
2585     });
2586     llvm::sort(Features);
2587     Attrs.addAttribute("target-features", llvm::join(Features, ","));
2588     AddedAttr = true;
2589   }
2590 
2591   return AddedAttr;
2592 }
2593 
2594 void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
2595                                           llvm::GlobalObject *GO) {
2596   const Decl *D = GD.getDecl();
2597   SetCommonAttributes(GD, GO);
2598 
2599   if (D) {
2600     if (auto *GV = dyn_cast<llvm::GlobalVariable>(GO)) {
2601       if (D->hasAttr<RetainAttr>())
2602         addUsedGlobal(GV);
2603       if (auto *SA = D->getAttr<PragmaClangBSSSectionAttr>())
2604         GV->addAttribute("bss-section", SA->getName());
2605       if (auto *SA = D->getAttr<PragmaClangDataSectionAttr>())
2606         GV->addAttribute("data-section", SA->getName());
2607       if (auto *SA = D->getAttr<PragmaClangRodataSectionAttr>())
2608         GV->addAttribute("rodata-section", SA->getName());
2609       if (auto *SA = D->getAttr<PragmaClangRelroSectionAttr>())
2610         GV->addAttribute("relro-section", SA->getName());
2611     }
2612 
2613     if (auto *F = dyn_cast<llvm::Function>(GO)) {
2614       if (D->hasAttr<RetainAttr>())
2615         addUsedGlobal(F);
2616       if (auto *SA = D->getAttr<PragmaClangTextSectionAttr>())
2617         if (!D->getAttr<SectionAttr>())
2618           F->addFnAttr("implicit-section-name", SA->getName());
2619 
2620       llvm::AttrBuilder Attrs(F->getContext());
2621       if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
2622         // We know that GetCPUAndFeaturesAttributes will always have the
2623         // newest set, since it has the newest possible FunctionDecl, so the
2624         // new ones should replace the old.
2625         llvm::AttributeMask RemoveAttrs;
2626         RemoveAttrs.addAttribute("target-cpu");
2627         RemoveAttrs.addAttribute("target-features");
2628         RemoveAttrs.addAttribute("tune-cpu");
2629         F->removeFnAttrs(RemoveAttrs);
2630         F->addFnAttrs(Attrs);
2631       }
2632     }
2633 
2634     if (const auto *CSA = D->getAttr<CodeSegAttr>())
2635       GO->setSection(CSA->getName());
2636     else if (const auto *SA = D->getAttr<SectionAttr>())
2637       GO->setSection(SA->getName());
2638   }
2639 
2640   getTargetCodeGenInfo().setTargetAttributes(D, GO, *this);
2641 }
2642 
2643 void CodeGenModule::SetInternalFunctionAttributes(GlobalDecl GD,
2644                                                   llvm::Function *F,
2645                                                   const CGFunctionInfo &FI) {
2646   const Decl *D = GD.getDecl();
2647   SetLLVMFunctionAttributes(GD, FI, F, /*IsThunk=*/false);
2648   SetLLVMFunctionAttributesForDefinition(D, F);
2649 
2650   F->setLinkage(llvm::Function::InternalLinkage);
2651 
2652   setNonAliasAttributes(GD, F);
2653 }
2654 
2655 static void setLinkageForGV(llvm::GlobalValue *GV, const NamedDecl *ND) {
2656   // Set linkage and visibility in case we never see a definition.
2657   LinkageInfo LV = ND->getLinkageAndVisibility();
2658   // Don't set internal linkage on declarations.
2659   // "extern_weak" is overloaded in LLVM; we probably should have
2660   // separate linkage types for this.
2661   if (isExternallyVisible(LV.getLinkage()) &&
2662       (ND->hasAttr<WeakAttr>() || ND->isWeakImported()))
2663     GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
2664 }
2665 
2666 void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
2667                                                        llvm::Function *F) {
2668   // Only if we are checking indirect calls.
2669   if (!LangOpts.Sanitize.has(SanitizerKind::CFIICall))
2670     return;
2671 
2672   // Non-static class methods are handled via vtable or member function pointer
2673   // checks elsewhere.
2674   if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
2675     return;
2676 
2677   llvm::Metadata *MD = CreateMetadataIdentifierForType(FD->getType());
2678   F->addTypeMetadata(0, MD);
2679   F->addTypeMetadata(0, CreateMetadataIdentifierGeneralized(FD->getType()));
2680 
2681   // Emit a hash-based bit set entry for cross-DSO calls.
2682   if (CodeGenOpts.SanitizeCfiCrossDso)
2683     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
2684       F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
2685 }
2686 
2687 void CodeGenModule::setKCFIType(const FunctionDecl *FD, llvm::Function *F) {
2688   llvm::LLVMContext &Ctx = F->getContext();
2689   llvm::MDBuilder MDB(Ctx);
2690   F->setMetadata(llvm::LLVMContext::MD_kcfi_type,
2691                  llvm::MDNode::get(
2692                      Ctx, MDB.createConstant(CreateKCFITypeId(FD->getType()))));
2693 }
2694 
2695 static bool allowKCFIIdentifier(StringRef Name) {
2696   // KCFI type identifier constants are only necessary for external assembly
2697   // functions, which means it's safe to skip unusual names. Subset of
2698   // MCAsmInfo::isAcceptableChar() and MCAsmInfoXCOFF::isAcceptableChar().
2699   return llvm::all_of(Name, [](const char &C) {
2700     return llvm::isAlnum(C) || C == '_' || C == '.';
2701   });
2702 }
2703 
2704 void CodeGenModule::finalizeKCFITypes() {
2705   llvm::Module &M = getModule();
2706   for (auto &F : M.functions()) {
2707     // Remove KCFI type metadata from non-address-taken local functions.
2708     bool AddressTaken = F.hasAddressTaken();
2709     if (!AddressTaken && F.hasLocalLinkage())
2710       F.eraseMetadata(llvm::LLVMContext::MD_kcfi_type);
2711 
2712     // Generate a constant with the expected KCFI type identifier for all
2713     // address-taken function declarations to support annotating indirectly
2714     // called assembly functions.
2715     if (!AddressTaken || !F.isDeclaration())
2716       continue;
2717 
2718     const llvm::ConstantInt *Type;
2719     if (const llvm::MDNode *MD = F.getMetadata(llvm::LLVMContext::MD_kcfi_type))
2720       Type = llvm::mdconst::extract<llvm::ConstantInt>(MD->getOperand(0));
2721     else
2722       continue;
2723 
2724     StringRef Name = F.getName();
2725     if (!allowKCFIIdentifier(Name))
2726       continue;
2727 
2728     std::string Asm = (".weak __kcfi_typeid_" + Name + "\n.set __kcfi_typeid_" +
2729                        Name + ", " + Twine(Type->getZExtValue()) + "\n")
2730                           .str();
2731     M.appendModuleInlineAsm(Asm);
2732   }
2733 }
2734 
2735 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
2736                                           bool IsIncompleteFunction,
2737                                           bool IsThunk) {
2738 
2739   if (llvm::Intrinsic::ID IID = F->getIntrinsicID()) {
2740     // If this is an intrinsic function, set the function's attributes
2741     // to the intrinsic's attributes.
2742     F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), IID));
2743     return;
2744   }
2745 
2746   const auto *FD = cast<FunctionDecl>(GD.getDecl());
2747 
2748   if (!IsIncompleteFunction)
2749     SetLLVMFunctionAttributes(GD, getTypes().arrangeGlobalDeclaration(GD), F,
2750                               IsThunk);
2751 
2752   // Add the Returned attribute for "this", except for iOS 5 and earlier
2753   // where substantial code, including the libstdc++ dylib, was compiled with
2754   // GCC and does not actually return "this".
2755   if (!IsThunk && getCXXABI().HasThisReturn(GD) &&
2756       !(getTriple().isiOS() && getTriple().isOSVersionLT(6))) {
2757     assert(!F->arg_empty() &&
2758            F->arg_begin()->getType()
2759              ->canLosslesslyBitCastTo(F->getReturnType()) &&
2760            "unexpected this return");
2761     F->addParamAttr(0, llvm::Attribute::Returned);
2762   }
2763 
2764   // Only a few attributes are set on declarations; these may later be
2765   // overridden by a definition.
2766 
2767   setLinkageForGV(F, FD);
2768   setGVProperties(F, FD);
2769 
2770   // Setup target-specific attributes.
2771   if (!IsIncompleteFunction && F->isDeclaration())
2772     getTargetCodeGenInfo().setTargetAttributes(FD, F, *this);
2773 
2774   if (const auto *CSA = FD->getAttr<CodeSegAttr>())
2775     F->setSection(CSA->getName());
2776   else if (const auto *SA = FD->getAttr<SectionAttr>())
2777      F->setSection(SA->getName());
2778 
2779   if (const auto *EA = FD->getAttr<ErrorAttr>()) {
2780     if (EA->isError())
2781       F->addFnAttr("dontcall-error", EA->getUserDiagnostic());
2782     else if (EA->isWarning())
2783       F->addFnAttr("dontcall-warn", EA->getUserDiagnostic());
2784   }
2785 
2786   // If we plan on emitting this inline builtin, we can't treat it as a builtin.
2787   if (FD->isInlineBuiltinDeclaration()) {
2788     const FunctionDecl *FDBody;
2789     bool HasBody = FD->hasBody(FDBody);
2790     (void)HasBody;
2791     assert(HasBody && "Inline builtin declarations should always have an "
2792                       "available body!");
2793     if (shouldEmitFunction(FDBody))
2794       F->addFnAttr(llvm::Attribute::NoBuiltin);
2795   }
2796 
2797   if (FD->isReplaceableGlobalAllocationFunction()) {
2798     // A replaceable global allocation function does not act like a builtin by
2799     // default, only if it is invoked by a new-expression or delete-expression.
2800     F->addFnAttr(llvm::Attribute::NoBuiltin);
2801   }
2802 
2803   if (isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))
2804     F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2805   else if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
2806     if (MD->isVirtual())
2807       F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2808 
2809   // Don't emit entries for function declarations in the cross-DSO mode. This
2810   // is handled with better precision by the receiving DSO. But if jump tables
2811   // are non-canonical then we need type metadata in order to produce the local
2812   // jump table.
2813   if (!CodeGenOpts.SanitizeCfiCrossDso ||
2814       !CodeGenOpts.SanitizeCfiCanonicalJumpTables)
2815     CreateFunctionTypeMetadataForIcall(FD, F);
2816 
2817   if (LangOpts.Sanitize.has(SanitizerKind::KCFI))
2818     setKCFIType(FD, F);
2819 
2820   if (getLangOpts().OpenMP && FD->hasAttr<OMPDeclareSimdDeclAttr>())
2821     getOpenMPRuntime().emitDeclareSimdFunction(FD, F);
2822 
2823   if (CodeGenOpts.InlineMaxStackSize != UINT_MAX)
2824     F->addFnAttr("inline-max-stacksize", llvm::utostr(CodeGenOpts.InlineMaxStackSize));
2825 
2826   if (const auto *CB = FD->getAttr<CallbackAttr>()) {
2827     // Annotate the callback behavior as metadata:
2828     //  - The callback callee (as argument number).
2829     //  - The callback payloads (as argument numbers).
2830     llvm::LLVMContext &Ctx = F->getContext();
2831     llvm::MDBuilder MDB(Ctx);
2832 
2833     // The payload indices are all but the first one in the encoding. The first
2834     // identifies the callback callee.
2835     int CalleeIdx = *CB->encoding_begin();
2836     ArrayRef<int> PayloadIndices(CB->encoding_begin() + 1, CB->encoding_end());
2837     F->addMetadata(llvm::LLVMContext::MD_callback,
2838                    *llvm::MDNode::get(Ctx, {MDB.createCallbackEncoding(
2839                                                CalleeIdx, PayloadIndices,
2840                                                /* VarArgsArePassed */ false)}));
2841   }
2842 }
2843 
2844 void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {
2845   assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
2846          "Only globals with definition can force usage.");
2847   LLVMUsed.emplace_back(GV);
2848 }
2849 
2850 void CodeGenModule::addCompilerUsedGlobal(llvm::GlobalValue *GV) {
2851   assert(!GV->isDeclaration() &&
2852          "Only globals with definition can force usage.");
2853   LLVMCompilerUsed.emplace_back(GV);
2854 }
2855 
2856 void CodeGenModule::addUsedOrCompilerUsedGlobal(llvm::GlobalValue *GV) {
2857   assert((isa<llvm::Function>(GV) || !GV->isDeclaration()) &&
2858          "Only globals with definition can force usage.");
2859   if (getTriple().isOSBinFormatELF())
2860     LLVMCompilerUsed.emplace_back(GV);
2861   else
2862     LLVMUsed.emplace_back(GV);
2863 }
2864 
2865 static void emitUsed(CodeGenModule &CGM, StringRef Name,
2866                      std::vector<llvm::WeakTrackingVH> &List) {
2867   // Don't create llvm.used if there is no need.
2868   if (List.empty())
2869     return;
2870 
2871   // Convert List to what ConstantArray needs.
2872   SmallVector<llvm::Constant*, 8> UsedArray;
2873   UsedArray.resize(List.size());
2874   for (unsigned i = 0, e = List.size(); i != e; ++i) {
2875     UsedArray[i] =
2876         llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
2877             cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
2878   }
2879 
2880   if (UsedArray.empty())
2881     return;
2882   llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
2883 
2884   auto *GV = new llvm::GlobalVariable(
2885       CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,
2886       llvm::ConstantArray::get(ATy, UsedArray), Name);
2887 
2888   GV->setSection("llvm.metadata");
2889 }
2890 
2891 void CodeGenModule::emitLLVMUsed() {
2892   emitUsed(*this, "llvm.used", LLVMUsed);
2893   emitUsed(*this, "llvm.compiler.used", LLVMCompilerUsed);
2894 }
2895 
2896 void CodeGenModule::AppendLinkerOptions(StringRef Opts) {
2897   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opts);
2898   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2899 }
2900 
2901 void CodeGenModule::AddDetectMismatch(StringRef Name, StringRef Value) {
2902   llvm::SmallString<32> Opt;
2903   getTargetCodeGenInfo().getDetectMismatchOption(Name, Value, Opt);
2904   if (Opt.empty())
2905     return;
2906   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2907   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2908 }
2909 
2910 void CodeGenModule::AddDependentLib(StringRef Lib) {
2911   auto &C = getLLVMContext();
2912   if (getTarget().getTriple().isOSBinFormatELF()) {
2913       ELFDependentLibraries.push_back(
2914         llvm::MDNode::get(C, llvm::MDString::get(C, Lib)));
2915     return;
2916   }
2917 
2918   llvm::SmallString<24> Opt;
2919   getTargetCodeGenInfo().getDependentLibraryOption(Lib, Opt);
2920   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2921   LinkerOptionsMetadata.push_back(llvm::MDNode::get(C, MDOpts));
2922 }
2923 
2924 /// Add link options implied by the given module, including modules
2925 /// it depends on, using a postorder walk.
2926 static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
2927                                     SmallVectorImpl<llvm::MDNode *> &Metadata,
2928                                     llvm::SmallPtrSet<Module *, 16> &Visited) {
2929   // Import this module's parent.
2930   if (Mod->Parent && Visited.insert(Mod->Parent).second) {
2931     addLinkOptionsPostorder(CGM, Mod->Parent, Metadata, Visited);
2932   }
2933 
2934   // Import this module's dependencies.
2935   for (Module *Import : llvm::reverse(Mod->Imports)) {
2936     if (Visited.insert(Import).second)
2937       addLinkOptionsPostorder(CGM, Import, Metadata, Visited);
2938   }
2939 
2940   // Add linker options to link against the libraries/frameworks
2941   // described by this module.
2942   llvm::LLVMContext &Context = CGM.getLLVMContext();
2943   bool IsELF = CGM.getTarget().getTriple().isOSBinFormatELF();
2944 
2945   // For modules that use export_as for linking, use that module
2946   // name instead.
2947   if (Mod->UseExportAsModuleLinkName)
2948     return;
2949 
2950   for (const Module::LinkLibrary &LL : llvm::reverse(Mod->LinkLibraries)) {
2951     // Link against a framework.  Frameworks are currently Darwin only, so we
2952     // don't to ask TargetCodeGenInfo for the spelling of the linker option.
2953     if (LL.IsFramework) {
2954       llvm::Metadata *Args[2] = {llvm::MDString::get(Context, "-framework"),
2955                                  llvm::MDString::get(Context, LL.Library)};
2956 
2957       Metadata.push_back(llvm::MDNode::get(Context, Args));
2958       continue;
2959     }
2960 
2961     // Link against a library.
2962     if (IsELF) {
2963       llvm::Metadata *Args[2] = {
2964           llvm::MDString::get(Context, "lib"),
2965           llvm::MDString::get(Context, LL.Library),
2966       };
2967       Metadata.push_back(llvm::MDNode::get(Context, Args));
2968     } else {
2969       llvm::SmallString<24> Opt;
2970       CGM.getTargetCodeGenInfo().getDependentLibraryOption(LL.Library, Opt);
2971       auto *OptString = llvm::MDString::get(Context, Opt);
2972       Metadata.push_back(llvm::MDNode::get(Context, OptString));
2973     }
2974   }
2975 }
2976 
2977 void CodeGenModule::EmitModuleInitializers(clang::Module *Primary) {
2978   assert(Primary->isNamedModuleUnit() &&
2979          "We should only emit module initializers for named modules.");
2980 
2981   // Emit the initializers in the order that sub-modules appear in the
2982   // source, first Global Module Fragments, if present.
2983   if (auto GMF = Primary->getGlobalModuleFragment()) {
2984     for (Decl *D : getContext().getModuleInitializers(GMF)) {
2985       if (isa<ImportDecl>(D))
2986         continue;
2987       assert(isa<VarDecl>(D) && "GMF initializer decl is not a var?");
2988       EmitTopLevelDecl(D);
2989     }
2990   }
2991   // Second any associated with the module, itself.
2992   for (Decl *D : getContext().getModuleInitializers(Primary)) {
2993     // Skip import decls, the inits for those are called explicitly.
2994     if (isa<ImportDecl>(D))
2995       continue;
2996     EmitTopLevelDecl(D);
2997   }
2998   // Third any associated with the Privat eMOdule Fragment, if present.
2999   if (auto PMF = Primary->getPrivateModuleFragment()) {
3000     for (Decl *D : getContext().getModuleInitializers(PMF)) {
3001       // Skip import decls, the inits for those are called explicitly.
3002       if (isa<ImportDecl>(D))
3003         continue;
3004       assert(isa<VarDecl>(D) && "PMF initializer decl is not a var?");
3005       EmitTopLevelDecl(D);
3006     }
3007   }
3008 }
3009 
3010 void CodeGenModule::EmitModuleLinkOptions() {
3011   // Collect the set of all of the modules we want to visit to emit link
3012   // options, which is essentially the imported modules and all of their
3013   // non-explicit child modules.
3014   llvm::SetVector<clang::Module *> LinkModules;
3015   llvm::SmallPtrSet<clang::Module *, 16> Visited;
3016   SmallVector<clang::Module *, 16> Stack;
3017 
3018   // Seed the stack with imported modules.
3019   for (Module *M : ImportedModules) {
3020     // Do not add any link flags when an implementation TU of a module imports
3021     // a header of that same module.
3022     if (M->getTopLevelModuleName() == getLangOpts().CurrentModule &&
3023         !getLangOpts().isCompilingModule())
3024       continue;
3025     if (Visited.insert(M).second)
3026       Stack.push_back(M);
3027   }
3028 
3029   // Find all of the modules to import, making a little effort to prune
3030   // non-leaf modules.
3031   while (!Stack.empty()) {
3032     clang::Module *Mod = Stack.pop_back_val();
3033 
3034     bool AnyChildren = false;
3035 
3036     // Visit the submodules of this module.
3037     for (const auto &SM : Mod->submodules()) {
3038       // Skip explicit children; they need to be explicitly imported to be
3039       // linked against.
3040       if (SM->IsExplicit)
3041         continue;
3042 
3043       if (Visited.insert(SM).second) {
3044         Stack.push_back(SM);
3045         AnyChildren = true;
3046       }
3047     }
3048 
3049     // We didn't find any children, so add this module to the list of
3050     // modules to link against.
3051     if (!AnyChildren) {
3052       LinkModules.insert(Mod);
3053     }
3054   }
3055 
3056   // Add link options for all of the imported modules in reverse topological
3057   // order.  We don't do anything to try to order import link flags with respect
3058   // to linker options inserted by things like #pragma comment().
3059   SmallVector<llvm::MDNode *, 16> MetadataArgs;
3060   Visited.clear();
3061   for (Module *M : LinkModules)
3062     if (Visited.insert(M).second)
3063       addLinkOptionsPostorder(*this, M, MetadataArgs, Visited);
3064   std::reverse(MetadataArgs.begin(), MetadataArgs.end());
3065   LinkerOptionsMetadata.append(MetadataArgs.begin(), MetadataArgs.end());
3066 
3067   // Add the linker options metadata flag.
3068   auto *NMD = getModule().getOrInsertNamedMetadata("llvm.linker.options");
3069   for (auto *MD : LinkerOptionsMetadata)
3070     NMD->addOperand(MD);
3071 }
3072 
3073 void CodeGenModule::EmitDeferred() {
3074   // Emit deferred declare target declarations.
3075   if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
3076     getOpenMPRuntime().emitDeferredTargetDecls();
3077 
3078   // Emit code for any potentially referenced deferred decls.  Since a
3079   // previously unused static decl may become used during the generation of code
3080   // for a static function, iterate until no changes are made.
3081 
3082   if (!DeferredVTables.empty()) {
3083     EmitDeferredVTables();
3084 
3085     // Emitting a vtable doesn't directly cause more vtables to
3086     // become deferred, although it can cause functions to be
3087     // emitted that then need those vtables.
3088     assert(DeferredVTables.empty());
3089   }
3090 
3091   // Emit CUDA/HIP static device variables referenced by host code only.
3092   // Note we should not clear CUDADeviceVarODRUsedByHost since it is still
3093   // needed for further handling.
3094   if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice)
3095     llvm::append_range(DeferredDeclsToEmit,
3096                        getContext().CUDADeviceVarODRUsedByHost);
3097 
3098   // Stop if we're out of both deferred vtables and deferred declarations.
3099   if (DeferredDeclsToEmit.empty())
3100     return;
3101 
3102   // Grab the list of decls to emit. If EmitGlobalDefinition schedules more
3103   // work, it will not interfere with this.
3104   std::vector<GlobalDecl> CurDeclsToEmit;
3105   CurDeclsToEmit.swap(DeferredDeclsToEmit);
3106 
3107   for (GlobalDecl &D : CurDeclsToEmit) {
3108     // We should call GetAddrOfGlobal with IsForDefinition set to true in order
3109     // to get GlobalValue with exactly the type we need, not something that
3110     // might had been created for another decl with the same mangled name but
3111     // different type.
3112     llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(
3113         GetAddrOfGlobal(D, ForDefinition));
3114 
3115     // In case of different address spaces, we may still get a cast, even with
3116     // IsForDefinition equal to true. Query mangled names table to get
3117     // GlobalValue.
3118     if (!GV)
3119       GV = GetGlobalValue(getMangledName(D));
3120 
3121     // Make sure GetGlobalValue returned non-null.
3122     assert(GV);
3123 
3124     // Check to see if we've already emitted this.  This is necessary
3125     // for a couple of reasons: first, decls can end up in the
3126     // deferred-decls queue multiple times, and second, decls can end
3127     // up with definitions in unusual ways (e.g. by an extern inline
3128     // function acquiring a strong function redefinition).  Just
3129     // ignore these cases.
3130     if (!GV->isDeclaration())
3131       continue;
3132 
3133     // If this is OpenMP, check if it is legal to emit this global normally.
3134     if (LangOpts.OpenMP && OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(D))
3135       continue;
3136 
3137     // Otherwise, emit the definition and move on to the next one.
3138     EmitGlobalDefinition(D, GV);
3139 
3140     // If we found out that we need to emit more decls, do that recursively.
3141     // This has the advantage that the decls are emitted in a DFS and related
3142     // ones are close together, which is convenient for testing.
3143     if (!DeferredVTables.empty() || !DeferredDeclsToEmit.empty()) {
3144       EmitDeferred();
3145       assert(DeferredVTables.empty() && DeferredDeclsToEmit.empty());
3146     }
3147   }
3148 }
3149 
3150 void CodeGenModule::EmitVTablesOpportunistically() {
3151   // Try to emit external vtables as available_externally if they have emitted
3152   // all inlined virtual functions.  It runs after EmitDeferred() and therefore
3153   // is not allowed to create new references to things that need to be emitted
3154   // lazily. Note that it also uses fact that we eagerly emitting RTTI.
3155 
3156   assert((OpportunisticVTables.empty() || shouldOpportunisticallyEmitVTables())
3157          && "Only emit opportunistic vtables with optimizations");
3158 
3159   for (const CXXRecordDecl *RD : OpportunisticVTables) {
3160     assert(getVTables().isVTableExternal(RD) &&
3161            "This queue should only contain external vtables");
3162     if (getCXXABI().canSpeculativelyEmitVTable(RD))
3163       VTables.GenerateClassData(RD);
3164   }
3165   OpportunisticVTables.clear();
3166 }
3167 
3168 void CodeGenModule::EmitGlobalAnnotations() {
3169   for (const auto& [MangledName, VD] : DeferredAnnotations) {
3170     llvm::GlobalValue *GV = GetGlobalValue(MangledName);
3171     if (GV)
3172       AddGlobalAnnotations(VD, GV);
3173   }
3174   DeferredAnnotations.clear();
3175 
3176   if (Annotations.empty())
3177     return;
3178 
3179   // Create a new global variable for the ConstantStruct in the Module.
3180   llvm::Constant *Array = llvm::ConstantArray::get(llvm::ArrayType::get(
3181     Annotations[0]->getType(), Annotations.size()), Annotations);
3182   auto *gv = new llvm::GlobalVariable(getModule(), Array->getType(), false,
3183                                       llvm::GlobalValue::AppendingLinkage,
3184                                       Array, "llvm.global.annotations");
3185   gv->setSection(AnnotationSection);
3186 }
3187 
3188 llvm::Constant *CodeGenModule::EmitAnnotationString(StringRef Str) {
3189   llvm::Constant *&AStr = AnnotationStrings[Str];
3190   if (AStr)
3191     return AStr;
3192 
3193   // Not found yet, create a new global.
3194   llvm::Constant *s = llvm::ConstantDataArray::getString(getLLVMContext(), Str);
3195   auto *gv = new llvm::GlobalVariable(
3196       getModule(), s->getType(), true, llvm::GlobalValue::PrivateLinkage, s,
3197       ".str", nullptr, llvm::GlobalValue::NotThreadLocal,
3198       ConstGlobalsPtrTy->getAddressSpace());
3199   gv->setSection(AnnotationSection);
3200   gv->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3201   AStr = gv;
3202   return gv;
3203 }
3204 
3205 llvm::Constant *CodeGenModule::EmitAnnotationUnit(SourceLocation Loc) {
3206   SourceManager &SM = getContext().getSourceManager();
3207   PresumedLoc PLoc = SM.getPresumedLoc(Loc);
3208   if (PLoc.isValid())
3209     return EmitAnnotationString(PLoc.getFilename());
3210   return EmitAnnotationString(SM.getBufferName(Loc));
3211 }
3212 
3213 llvm::Constant *CodeGenModule::EmitAnnotationLineNo(SourceLocation L) {
3214   SourceManager &SM = getContext().getSourceManager();
3215   PresumedLoc PLoc = SM.getPresumedLoc(L);
3216   unsigned LineNo = PLoc.isValid() ? PLoc.getLine() :
3217     SM.getExpansionLineNumber(L);
3218   return llvm::ConstantInt::get(Int32Ty, LineNo);
3219 }
3220 
3221 llvm::Constant *CodeGenModule::EmitAnnotationArgs(const AnnotateAttr *Attr) {
3222   ArrayRef<Expr *> Exprs = {Attr->args_begin(), Attr->args_size()};
3223   if (Exprs.empty())
3224     return llvm::ConstantPointerNull::get(ConstGlobalsPtrTy);
3225 
3226   llvm::FoldingSetNodeID ID;
3227   for (Expr *E : Exprs) {
3228     ID.Add(cast<clang::ConstantExpr>(E)->getAPValueResult());
3229   }
3230   llvm::Constant *&Lookup = AnnotationArgs[ID.ComputeHash()];
3231   if (Lookup)
3232     return Lookup;
3233 
3234   llvm::SmallVector<llvm::Constant *, 4> LLVMArgs;
3235   LLVMArgs.reserve(Exprs.size());
3236   ConstantEmitter ConstEmiter(*this);
3237   llvm::transform(Exprs, std::back_inserter(LLVMArgs), [&](const Expr *E) {
3238     const auto *CE = cast<clang::ConstantExpr>(E);
3239     return ConstEmiter.emitAbstract(CE->getBeginLoc(), CE->getAPValueResult(),
3240                                     CE->getType());
3241   });
3242   auto *Struct = llvm::ConstantStruct::getAnon(LLVMArgs);
3243   auto *GV = new llvm::GlobalVariable(getModule(), Struct->getType(), true,
3244                                       llvm::GlobalValue::PrivateLinkage, Struct,
3245                                       ".args");
3246   GV->setSection(AnnotationSection);
3247   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3248 
3249   Lookup = GV;
3250   return GV;
3251 }
3252 
3253 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
3254                                                 const AnnotateAttr *AA,
3255                                                 SourceLocation L) {
3256   // Get the globals for file name, annotation, and the line number.
3257   llvm::Constant *AnnoGV = EmitAnnotationString(AA->getAnnotation()),
3258                  *UnitGV = EmitAnnotationUnit(L),
3259                  *LineNoCst = EmitAnnotationLineNo(L),
3260                  *Args = EmitAnnotationArgs(AA);
3261 
3262   llvm::Constant *GVInGlobalsAS = GV;
3263   if (GV->getAddressSpace() !=
3264       getDataLayout().getDefaultGlobalsAddressSpace()) {
3265     GVInGlobalsAS = llvm::ConstantExpr::getAddrSpaceCast(
3266         GV,
3267         llvm::PointerType::get(
3268             GV->getContext(), getDataLayout().getDefaultGlobalsAddressSpace()));
3269   }
3270 
3271   // Create the ConstantStruct for the global annotation.
3272   llvm::Constant *Fields[] = {
3273       GVInGlobalsAS, AnnoGV, UnitGV, LineNoCst, Args,
3274   };
3275   return llvm::ConstantStruct::getAnon(Fields);
3276 }
3277 
3278 void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D,
3279                                          llvm::GlobalValue *GV) {
3280   assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
3281   // Get the struct elements for these annotations.
3282   for (const auto *I : D->specific_attrs<AnnotateAttr>())
3283     Annotations.push_back(EmitAnnotateAttr(GV, I, D->getLocation()));
3284 }
3285 
3286 bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind, llvm::Function *Fn,
3287                                        SourceLocation Loc) const {
3288   const auto &NoSanitizeL = getContext().getNoSanitizeList();
3289   // NoSanitize by function name.
3290   if (NoSanitizeL.containsFunction(Kind, Fn->getName()))
3291     return true;
3292   // NoSanitize by location. Check "mainfile" prefix.
3293   auto &SM = Context.getSourceManager();
3294   FileEntryRef MainFile = *SM.getFileEntryRefForID(SM.getMainFileID());
3295   if (NoSanitizeL.containsMainFile(Kind, MainFile.getName()))
3296     return true;
3297 
3298   // Check "src" prefix.
3299   if (Loc.isValid())
3300     return NoSanitizeL.containsLocation(Kind, Loc);
3301   // If location is unknown, this may be a compiler-generated function. Assume
3302   // it's located in the main file.
3303   return NoSanitizeL.containsFile(Kind, MainFile.getName());
3304 }
3305 
3306 bool CodeGenModule::isInNoSanitizeList(SanitizerMask Kind,
3307                                        llvm::GlobalVariable *GV,
3308                                        SourceLocation Loc, QualType Ty,
3309                                        StringRef Category) const {
3310   const auto &NoSanitizeL = getContext().getNoSanitizeList();
3311   if (NoSanitizeL.containsGlobal(Kind, GV->getName(), Category))
3312     return true;
3313   auto &SM = Context.getSourceManager();
3314   if (NoSanitizeL.containsMainFile(
3315           Kind, SM.getFileEntryRefForID(SM.getMainFileID())->getName(),
3316           Category))
3317     return true;
3318   if (NoSanitizeL.containsLocation(Kind, Loc, Category))
3319     return true;
3320 
3321   // Check global type.
3322   if (!Ty.isNull()) {
3323     // Drill down the array types: if global variable of a fixed type is
3324     // not sanitized, we also don't instrument arrays of them.
3325     while (auto AT = dyn_cast<ArrayType>(Ty.getTypePtr()))
3326       Ty = AT->getElementType();
3327     Ty = Ty.getCanonicalType().getUnqualifiedType();
3328     // Only record types (classes, structs etc.) are ignored.
3329     if (Ty->isRecordType()) {
3330       std::string TypeStr = Ty.getAsString(getContext().getPrintingPolicy());
3331       if (NoSanitizeL.containsType(Kind, TypeStr, Category))
3332         return true;
3333     }
3334   }
3335   return false;
3336 }
3337 
3338 bool CodeGenModule::imbueXRayAttrs(llvm::Function *Fn, SourceLocation Loc,
3339                                    StringRef Category) const {
3340   const auto &XRayFilter = getContext().getXRayFilter();
3341   using ImbueAttr = XRayFunctionFilter::ImbueAttribute;
3342   auto Attr = ImbueAttr::NONE;
3343   if (Loc.isValid())
3344     Attr = XRayFilter.shouldImbueLocation(Loc, Category);
3345   if (Attr == ImbueAttr::NONE)
3346     Attr = XRayFilter.shouldImbueFunction(Fn->getName());
3347   switch (Attr) {
3348   case ImbueAttr::NONE:
3349     return false;
3350   case ImbueAttr::ALWAYS:
3351     Fn->addFnAttr("function-instrument", "xray-always");
3352     break;
3353   case ImbueAttr::ALWAYS_ARG1:
3354     Fn->addFnAttr("function-instrument", "xray-always");
3355     Fn->addFnAttr("xray-log-args", "1");
3356     break;
3357   case ImbueAttr::NEVER:
3358     Fn->addFnAttr("function-instrument", "xray-never");
3359     break;
3360   }
3361   return true;
3362 }
3363 
3364 ProfileList::ExclusionType
3365 CodeGenModule::isFunctionBlockedByProfileList(llvm::Function *Fn,
3366                                               SourceLocation Loc) const {
3367   const auto &ProfileList = getContext().getProfileList();
3368   // If the profile list is empty, then instrument everything.
3369   if (ProfileList.isEmpty())
3370     return ProfileList::Allow;
3371   CodeGenOptions::ProfileInstrKind Kind = getCodeGenOpts().getProfileInstr();
3372   // First, check the function name.
3373   if (auto V = ProfileList.isFunctionExcluded(Fn->getName(), Kind))
3374     return *V;
3375   // Next, check the source location.
3376   if (Loc.isValid())
3377     if (auto V = ProfileList.isLocationExcluded(Loc, Kind))
3378       return *V;
3379   // If location is unknown, this may be a compiler-generated function. Assume
3380   // it's located in the main file.
3381   auto &SM = Context.getSourceManager();
3382   if (auto MainFile = SM.getFileEntryRefForID(SM.getMainFileID()))
3383     if (auto V = ProfileList.isFileExcluded(MainFile->getName(), Kind))
3384       return *V;
3385   return ProfileList.getDefault(Kind);
3386 }
3387 
3388 ProfileList::ExclusionType
3389 CodeGenModule::isFunctionBlockedFromProfileInstr(llvm::Function *Fn,
3390                                                  SourceLocation Loc) const {
3391   auto V = isFunctionBlockedByProfileList(Fn, Loc);
3392   if (V != ProfileList::Allow)
3393     return V;
3394 
3395   auto NumGroups = getCodeGenOpts().ProfileTotalFunctionGroups;
3396   if (NumGroups > 1) {
3397     auto Group = llvm::crc32(arrayRefFromStringRef(Fn->getName())) % NumGroups;
3398     if (Group != getCodeGenOpts().ProfileSelectedFunctionGroup)
3399       return ProfileList::Skip;
3400   }
3401   return ProfileList::Allow;
3402 }
3403 
3404 bool CodeGenModule::MustBeEmitted(const ValueDecl *Global) {
3405   // Never defer when EmitAllDecls is specified.
3406   if (LangOpts.EmitAllDecls)
3407     return true;
3408 
3409   const auto *VD = dyn_cast<VarDecl>(Global);
3410   if (VD &&
3411       ((CodeGenOpts.KeepPersistentStorageVariables &&
3412         (VD->getStorageDuration() == SD_Static ||
3413          VD->getStorageDuration() == SD_Thread)) ||
3414        (CodeGenOpts.KeepStaticConsts && VD->getStorageDuration() == SD_Static &&
3415         VD->getType().isConstQualified())))
3416     return true;
3417 
3418   return getContext().DeclMustBeEmitted(Global);
3419 }
3420 
3421 bool CodeGenModule::MayBeEmittedEagerly(const ValueDecl *Global) {
3422   // In OpenMP 5.0 variables and function may be marked as
3423   // device_type(host/nohost) and we should not emit them eagerly unless we sure
3424   // that they must be emitted on the host/device. To be sure we need to have
3425   // seen a declare target with an explicit mentioning of the function, we know
3426   // we have if the level of the declare target attribute is -1. Note that we
3427   // check somewhere else if we should emit this at all.
3428   if (LangOpts.OpenMP >= 50 && !LangOpts.OpenMPSimd) {
3429     std::optional<OMPDeclareTargetDeclAttr *> ActiveAttr =
3430         OMPDeclareTargetDeclAttr::getActiveAttr(Global);
3431     if (!ActiveAttr || (*ActiveAttr)->getLevel() != (unsigned)-1)
3432       return false;
3433   }
3434 
3435   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
3436     if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
3437       // Implicit template instantiations may change linkage if they are later
3438       // explicitly instantiated, so they should not be emitted eagerly.
3439       return false;
3440   }
3441   if (const auto *VD = dyn_cast<VarDecl>(Global)) {
3442     if (Context.getInlineVariableDefinitionKind(VD) ==
3443         ASTContext::InlineVariableDefinitionKind::WeakUnknown)
3444       // A definition of an inline constexpr static data member may change
3445       // linkage later if it's redeclared outside the class.
3446       return false;
3447     if (CXX20ModuleInits && VD->getOwningModule() &&
3448         !VD->getOwningModule()->isModuleMapModule()) {
3449       // For CXX20, module-owned initializers need to be deferred, since it is
3450       // not known at this point if they will be run for the current module or
3451       // as part of the initializer for an imported one.
3452       return false;
3453     }
3454   }
3455   // If OpenMP is enabled and threadprivates must be generated like TLS, delay
3456   // codegen for global variables, because they may be marked as threadprivate.
3457   if (LangOpts.OpenMP && LangOpts.OpenMPUseTLS &&
3458       getContext().getTargetInfo().isTLSSupported() && isa<VarDecl>(Global) &&
3459       !Global->getType().isConstantStorage(getContext(), false, false) &&
3460       !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(Global))
3461     return false;
3462 
3463   return true;
3464 }
3465 
3466 ConstantAddress CodeGenModule::GetAddrOfMSGuidDecl(const MSGuidDecl *GD) {
3467   StringRef Name = getMangledName(GD);
3468 
3469   // The UUID descriptor should be pointer aligned.
3470   CharUnits Alignment = CharUnits::fromQuantity(PointerAlignInBytes);
3471 
3472   // Look for an existing global.
3473   if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
3474     return ConstantAddress(GV, GV->getValueType(), Alignment);
3475 
3476   ConstantEmitter Emitter(*this);
3477   llvm::Constant *Init;
3478 
3479   APValue &V = GD->getAsAPValue();
3480   if (!V.isAbsent()) {
3481     // If possible, emit the APValue version of the initializer. In particular,
3482     // this gets the type of the constant right.
3483     Init = Emitter.emitForInitializer(
3484         GD->getAsAPValue(), GD->getType().getAddressSpace(), GD->getType());
3485   } else {
3486     // As a fallback, directly construct the constant.
3487     // FIXME: This may get padding wrong under esoteric struct layout rules.
3488     // MSVC appears to create a complete type 'struct __s_GUID' that it
3489     // presumably uses to represent these constants.
3490     MSGuidDecl::Parts Parts = GD->getParts();
3491     llvm::Constant *Fields[4] = {
3492         llvm::ConstantInt::get(Int32Ty, Parts.Part1),
3493         llvm::ConstantInt::get(Int16Ty, Parts.Part2),
3494         llvm::ConstantInt::get(Int16Ty, Parts.Part3),
3495         llvm::ConstantDataArray::getRaw(
3496             StringRef(reinterpret_cast<char *>(Parts.Part4And5), 8), 8,
3497             Int8Ty)};
3498     Init = llvm::ConstantStruct::getAnon(Fields);
3499   }
3500 
3501   auto *GV = new llvm::GlobalVariable(
3502       getModule(), Init->getType(),
3503       /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
3504   if (supportsCOMDAT())
3505     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
3506   setDSOLocal(GV);
3507 
3508   if (!V.isAbsent()) {
3509     Emitter.finalize(GV);
3510     return ConstantAddress(GV, GV->getValueType(), Alignment);
3511   }
3512 
3513   llvm::Type *Ty = getTypes().ConvertTypeForMem(GD->getType());
3514   return ConstantAddress(GV, Ty, Alignment);
3515 }
3516 
3517 ConstantAddress CodeGenModule::GetAddrOfUnnamedGlobalConstantDecl(
3518     const UnnamedGlobalConstantDecl *GCD) {
3519   CharUnits Alignment = getContext().getTypeAlignInChars(GCD->getType());
3520 
3521   llvm::GlobalVariable **Entry = nullptr;
3522   Entry = &UnnamedGlobalConstantDeclMap[GCD];
3523   if (*Entry)
3524     return ConstantAddress(*Entry, (*Entry)->getValueType(), Alignment);
3525 
3526   ConstantEmitter Emitter(*this);
3527   llvm::Constant *Init;
3528 
3529   const APValue &V = GCD->getValue();
3530 
3531   assert(!V.isAbsent());
3532   Init = Emitter.emitForInitializer(V, GCD->getType().getAddressSpace(),
3533                                     GCD->getType());
3534 
3535   auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
3536                                       /*isConstant=*/true,
3537                                       llvm::GlobalValue::PrivateLinkage, Init,
3538                                       ".constant");
3539   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
3540   GV->setAlignment(Alignment.getAsAlign());
3541 
3542   Emitter.finalize(GV);
3543 
3544   *Entry = GV;
3545   return ConstantAddress(GV, GV->getValueType(), Alignment);
3546 }
3547 
3548 ConstantAddress CodeGenModule::GetAddrOfTemplateParamObject(
3549     const TemplateParamObjectDecl *TPO) {
3550   StringRef Name = getMangledName(TPO);
3551   CharUnits Alignment = getNaturalTypeAlignment(TPO->getType());
3552 
3553   if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
3554     return ConstantAddress(GV, GV->getValueType(), Alignment);
3555 
3556   ConstantEmitter Emitter(*this);
3557   llvm::Constant *Init = Emitter.emitForInitializer(
3558         TPO->getValue(), TPO->getType().getAddressSpace(), TPO->getType());
3559 
3560   if (!Init) {
3561     ErrorUnsupported(TPO, "template parameter object");
3562     return ConstantAddress::invalid();
3563   }
3564 
3565   llvm::GlobalValue::LinkageTypes Linkage =
3566       isExternallyVisible(TPO->getLinkageAndVisibility().getLinkage())
3567           ? llvm::GlobalValue::LinkOnceODRLinkage
3568           : llvm::GlobalValue::InternalLinkage;
3569   auto *GV = new llvm::GlobalVariable(getModule(), Init->getType(),
3570                                       /*isConstant=*/true, Linkage, Init, Name);
3571   setGVProperties(GV, TPO);
3572   if (supportsCOMDAT())
3573     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
3574   Emitter.finalize(GV);
3575 
3576     return ConstantAddress(GV, GV->getValueType(), Alignment);
3577 }
3578 
3579 ConstantAddress CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
3580   const AliasAttr *AA = VD->getAttr<AliasAttr>();
3581   assert(AA && "No alias?");
3582 
3583   CharUnits Alignment = getContext().getDeclAlign(VD);
3584   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
3585 
3586   // See if there is already something with the target's name in the module.
3587   llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
3588   if (Entry)
3589     return ConstantAddress(Entry, DeclTy, Alignment);
3590 
3591   llvm::Constant *Aliasee;
3592   if (isa<llvm::FunctionType>(DeclTy))
3593     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy,
3594                                       GlobalDecl(cast<FunctionDecl>(VD)),
3595                                       /*ForVTable=*/false);
3596   else
3597     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), DeclTy, LangAS::Default,
3598                                     nullptr);
3599 
3600   auto *F = cast<llvm::GlobalValue>(Aliasee);
3601   F->setLinkage(llvm::Function::ExternalWeakLinkage);
3602   WeakRefReferences.insert(F);
3603 
3604   return ConstantAddress(Aliasee, DeclTy, Alignment);
3605 }
3606 
3607 template <typename AttrT> static bool hasImplicitAttr(const ValueDecl *D) {
3608   if (!D)
3609     return false;
3610   if (auto *A = D->getAttr<AttrT>())
3611     return A->isImplicit();
3612   return D->isImplicit();
3613 }
3614 
3615 void CodeGenModule::EmitGlobal(GlobalDecl GD) {
3616   const auto *Global = cast<ValueDecl>(GD.getDecl());
3617 
3618   // Weak references don't produce any output by themselves.
3619   if (Global->hasAttr<WeakRefAttr>())
3620     return;
3621 
3622   // If this is an alias definition (which otherwise looks like a declaration)
3623   // emit it now.
3624   if (Global->hasAttr<AliasAttr>())
3625     return EmitAliasDefinition(GD);
3626 
3627   // IFunc like an alias whose value is resolved at runtime by calling resolver.
3628   if (Global->hasAttr<IFuncAttr>())
3629     return emitIFuncDefinition(GD);
3630 
3631   // If this is a cpu_dispatch multiversion function, emit the resolver.
3632   if (Global->hasAttr<CPUDispatchAttr>())
3633     return emitCPUDispatchDefinition(GD);
3634 
3635   // If this is CUDA, be selective about which declarations we emit.
3636   // Non-constexpr non-lambda implicit host device functions are not emitted
3637   // unless they are used on device side.
3638   if (LangOpts.CUDA) {
3639     if (LangOpts.CUDAIsDevice) {
3640       const auto *FD = dyn_cast<FunctionDecl>(Global);
3641       if ((!Global->hasAttr<CUDADeviceAttr>() ||
3642            (LangOpts.OffloadImplicitHostDeviceTemplates && FD &&
3643             hasImplicitAttr<CUDAHostAttr>(FD) &&
3644             hasImplicitAttr<CUDADeviceAttr>(FD) && !FD->isConstexpr() &&
3645             !isLambdaCallOperator(FD) &&
3646             !getContext().CUDAImplicitHostDeviceFunUsedByDevice.count(FD))) &&
3647           !Global->hasAttr<CUDAGlobalAttr>() &&
3648           !Global->hasAttr<CUDAConstantAttr>() &&
3649           !Global->hasAttr<CUDASharedAttr>() &&
3650           !Global->getType()->isCUDADeviceBuiltinSurfaceType() &&
3651           !Global->getType()->isCUDADeviceBuiltinTextureType() &&
3652           !(LangOpts.HIPStdPar && isa<FunctionDecl>(Global) &&
3653             !Global->hasAttr<CUDAHostAttr>()))
3654         return;
3655     } else {
3656       // We need to emit host-side 'shadows' for all global
3657       // device-side variables because the CUDA runtime needs their
3658       // size and host-side address in order to provide access to
3659       // their device-side incarnations.
3660 
3661       // So device-only functions are the only things we skip.
3662       if (isa<FunctionDecl>(Global) && !Global->hasAttr<CUDAHostAttr>() &&
3663           Global->hasAttr<CUDADeviceAttr>())
3664         return;
3665 
3666       assert((isa<FunctionDecl>(Global) || isa<VarDecl>(Global)) &&
3667              "Expected Variable or Function");
3668     }
3669   }
3670 
3671   if (LangOpts.OpenMP) {
3672     // If this is OpenMP, check if it is legal to emit this global normally.
3673     if (OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(GD))
3674       return;
3675     if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Global)) {
3676       if (MustBeEmitted(Global))
3677         EmitOMPDeclareReduction(DRD);
3678       return;
3679     }
3680     if (auto *DMD = dyn_cast<OMPDeclareMapperDecl>(Global)) {
3681       if (MustBeEmitted(Global))
3682         EmitOMPDeclareMapper(DMD);
3683       return;
3684     }
3685   }
3686 
3687   // Ignore declarations, they will be emitted on their first use.
3688   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
3689     // Update deferred annotations with the latest declaration if the function
3690     // function was already used or defined.
3691     if (FD->hasAttr<AnnotateAttr>()) {
3692       StringRef MangledName = getMangledName(GD);
3693       if (GetGlobalValue(MangledName))
3694         DeferredAnnotations[MangledName] = FD;
3695     }
3696 
3697     // Forward declarations are emitted lazily on first use.
3698     if (!FD->doesThisDeclarationHaveABody()) {
3699       if (!FD->doesDeclarationForceExternallyVisibleDefinition())
3700         return;
3701 
3702       StringRef MangledName = getMangledName(GD);
3703 
3704       // Compute the function info and LLVM type.
3705       const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
3706       llvm::Type *Ty = getTypes().GetFunctionType(FI);
3707 
3708       GetOrCreateLLVMFunction(MangledName, Ty, GD, /*ForVTable=*/false,
3709                               /*DontDefer=*/false);
3710       return;
3711     }
3712   } else {
3713     const auto *VD = cast<VarDecl>(Global);
3714     assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
3715     if (VD->isThisDeclarationADefinition() != VarDecl::Definition &&
3716         !Context.isMSStaticDataMemberInlineDefinition(VD)) {
3717       if (LangOpts.OpenMP) {
3718         // Emit declaration of the must-be-emitted declare target variable.
3719         if (std::optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
3720                 OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD)) {
3721 
3722           // If this variable has external storage and doesn't require special
3723           // link handling we defer to its canonical definition.
3724           if (VD->hasExternalStorage() &&
3725               Res != OMPDeclareTargetDeclAttr::MT_Link)
3726             return;
3727 
3728           bool UnifiedMemoryEnabled =
3729               getOpenMPRuntime().hasRequiresUnifiedSharedMemory();
3730           if ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
3731                *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
3732               !UnifiedMemoryEnabled) {
3733             (void)GetAddrOfGlobalVar(VD);
3734           } else {
3735             assert(((*Res == OMPDeclareTargetDeclAttr::MT_Link) ||
3736                     ((*Res == OMPDeclareTargetDeclAttr::MT_To ||
3737                       *Res == OMPDeclareTargetDeclAttr::MT_Enter) &&
3738                      UnifiedMemoryEnabled)) &&
3739                    "Link clause or to clause with unified memory expected.");
3740             (void)getOpenMPRuntime().getAddrOfDeclareTargetVar(VD);
3741           }
3742 
3743           return;
3744         }
3745       }
3746       // If this declaration may have caused an inline variable definition to
3747       // change linkage, make sure that it's emitted.
3748       if (Context.getInlineVariableDefinitionKind(VD) ==
3749           ASTContext::InlineVariableDefinitionKind::Strong)
3750         GetAddrOfGlobalVar(VD);
3751       return;
3752     }
3753   }
3754 
3755   // Defer code generation to first use when possible, e.g. if this is an inline
3756   // function. If the global must always be emitted, do it eagerly if possible
3757   // to benefit from cache locality.
3758   if (MustBeEmitted(Global) && MayBeEmittedEagerly(Global)) {
3759     // Emit the definition if it can't be deferred.
3760     EmitGlobalDefinition(GD);
3761     addEmittedDeferredDecl(GD);
3762     return;
3763   }
3764 
3765   // If we're deferring emission of a C++ variable with an
3766   // initializer, remember the order in which it appeared in the file.
3767   if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) &&
3768       cast<VarDecl>(Global)->hasInit()) {
3769     DelayedCXXInitPosition[Global] = CXXGlobalInits.size();
3770     CXXGlobalInits.push_back(nullptr);
3771   }
3772 
3773   StringRef MangledName = getMangledName(GD);
3774   if (GetGlobalValue(MangledName) != nullptr) {
3775     // The value has already been used and should therefore be emitted.
3776     addDeferredDeclToEmit(GD);
3777   } else if (MustBeEmitted(Global)) {
3778     // The value must be emitted, but cannot be emitted eagerly.
3779     assert(!MayBeEmittedEagerly(Global));
3780     addDeferredDeclToEmit(GD);
3781   } else {
3782     // Otherwise, remember that we saw a deferred decl with this name.  The
3783     // first use of the mangled name will cause it to move into
3784     // DeferredDeclsToEmit.
3785     DeferredDecls[MangledName] = GD;
3786   }
3787 }
3788 
3789 // Check if T is a class type with a destructor that's not dllimport.
3790 static bool HasNonDllImportDtor(QualType T) {
3791   if (const auto *RT = T->getBaseElementTypeUnsafe()->getAs<RecordType>())
3792     if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
3793       if (RD->getDestructor() && !RD->getDestructor()->hasAttr<DLLImportAttr>())
3794         return true;
3795 
3796   return false;
3797 }
3798 
3799 namespace {
3800   struct FunctionIsDirectlyRecursive
3801       : public ConstStmtVisitor<FunctionIsDirectlyRecursive, bool> {
3802     const StringRef Name;
3803     const Builtin::Context &BI;
3804     FunctionIsDirectlyRecursive(StringRef N, const Builtin::Context &C)
3805         : Name(N), BI(C) {}
3806 
3807     bool VisitCallExpr(const CallExpr *E) {
3808       const FunctionDecl *FD = E->getDirectCallee();
3809       if (!FD)
3810         return false;
3811       AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
3812       if (Attr && Name == Attr->getLabel())
3813         return true;
3814       unsigned BuiltinID = FD->getBuiltinID();
3815       if (!BuiltinID || !BI.isLibFunction(BuiltinID))
3816         return false;
3817       StringRef BuiltinName = BI.getName(BuiltinID);
3818       if (BuiltinName.startswith("__builtin_") &&
3819           Name == BuiltinName.slice(strlen("__builtin_"), StringRef::npos)) {
3820         return true;
3821       }
3822       return false;
3823     }
3824 
3825     bool VisitStmt(const Stmt *S) {
3826       for (const Stmt *Child : S->children())
3827         if (Child && this->Visit(Child))
3828           return true;
3829       return false;
3830     }
3831   };
3832 
3833   // Make sure we're not referencing non-imported vars or functions.
3834   struct DLLImportFunctionVisitor
3835       : public RecursiveASTVisitor<DLLImportFunctionVisitor> {
3836     bool SafeToInline = true;
3837 
3838     bool shouldVisitImplicitCode() const { return true; }
3839 
3840     bool VisitVarDecl(VarDecl *VD) {
3841       if (VD->getTLSKind()) {
3842         // A thread-local variable cannot be imported.
3843         SafeToInline = false;
3844         return SafeToInline;
3845       }
3846 
3847       // A variable definition might imply a destructor call.
3848       if (VD->isThisDeclarationADefinition())
3849         SafeToInline = !HasNonDllImportDtor(VD->getType());
3850 
3851       return SafeToInline;
3852     }
3853 
3854     bool VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
3855       if (const auto *D = E->getTemporary()->getDestructor())
3856         SafeToInline = D->hasAttr<DLLImportAttr>();
3857       return SafeToInline;
3858     }
3859 
3860     bool VisitDeclRefExpr(DeclRefExpr *E) {
3861       ValueDecl *VD = E->getDecl();
3862       if (isa<FunctionDecl>(VD))
3863         SafeToInline = VD->hasAttr<DLLImportAttr>();
3864       else if (VarDecl *V = dyn_cast<VarDecl>(VD))
3865         SafeToInline = !V->hasGlobalStorage() || V->hasAttr<DLLImportAttr>();
3866       return SafeToInline;
3867     }
3868 
3869     bool VisitCXXConstructExpr(CXXConstructExpr *E) {
3870       SafeToInline = E->getConstructor()->hasAttr<DLLImportAttr>();
3871       return SafeToInline;
3872     }
3873 
3874     bool VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
3875       CXXMethodDecl *M = E->getMethodDecl();
3876       if (!M) {
3877         // Call through a pointer to member function. This is safe to inline.
3878         SafeToInline = true;
3879       } else {
3880         SafeToInline = M->hasAttr<DLLImportAttr>();
3881       }
3882       return SafeToInline;
3883     }
3884 
3885     bool VisitCXXDeleteExpr(CXXDeleteExpr *E) {
3886       SafeToInline = E->getOperatorDelete()->hasAttr<DLLImportAttr>();
3887       return SafeToInline;
3888     }
3889 
3890     bool VisitCXXNewExpr(CXXNewExpr *E) {
3891       SafeToInline = E->getOperatorNew()->hasAttr<DLLImportAttr>();
3892       return SafeToInline;
3893     }
3894   };
3895 }
3896 
3897 // isTriviallyRecursive - Check if this function calls another
3898 // decl that, because of the asm attribute or the other decl being a builtin,
3899 // ends up pointing to itself.
3900 bool
3901 CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) {
3902   StringRef Name;
3903   if (getCXXABI().getMangleContext().shouldMangleDeclName(FD)) {
3904     // asm labels are a special kind of mangling we have to support.
3905     AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
3906     if (!Attr)
3907       return false;
3908     Name = Attr->getLabel();
3909   } else {
3910     Name = FD->getName();
3911   }
3912 
3913   FunctionIsDirectlyRecursive Walker(Name, Context.BuiltinInfo);
3914   const Stmt *Body = FD->getBody();
3915   return Body ? Walker.Visit(Body) : false;
3916 }
3917 
3918 bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
3919   if (getFunctionLinkage(GD) != llvm::Function::AvailableExternallyLinkage)
3920     return true;
3921 
3922   const auto *F = cast<FunctionDecl>(GD.getDecl());
3923   if (CodeGenOpts.OptimizationLevel == 0 && !F->hasAttr<AlwaysInlineAttr>())
3924     return false;
3925 
3926   // We don't import function bodies from other named module units since that
3927   // behavior may break ABI compatibility of the current unit.
3928   if (const Module *M = F->getOwningModule();
3929       M && M->getTopLevelModule()->isNamedModule() &&
3930       getContext().getCurrentNamedModule() != M->getTopLevelModule() &&
3931       !F->hasAttr<AlwaysInlineAttr>())
3932     return false;
3933 
3934   if (F->hasAttr<NoInlineAttr>())
3935     return false;
3936 
3937   if (F->hasAttr<DLLImportAttr>() && !F->hasAttr<AlwaysInlineAttr>()) {
3938     // Check whether it would be safe to inline this dllimport function.
3939     DLLImportFunctionVisitor Visitor;
3940     Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
3941     if (!Visitor.SafeToInline)
3942       return false;
3943 
3944     if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(F)) {
3945       // Implicit destructor invocations aren't captured in the AST, so the
3946       // check above can't see them. Check for them manually here.
3947       for (const Decl *Member : Dtor->getParent()->decls())
3948         if (isa<FieldDecl>(Member))
3949           if (HasNonDllImportDtor(cast<FieldDecl>(Member)->getType()))
3950             return false;
3951       for (const CXXBaseSpecifier &B : Dtor->getParent()->bases())
3952         if (HasNonDllImportDtor(B.getType()))
3953           return false;
3954     }
3955   }
3956 
3957   // Inline builtins declaration must be emitted. They often are fortified
3958   // functions.
3959   if (F->isInlineBuiltinDeclaration())
3960     return true;
3961 
3962   // PR9614. Avoid cases where the source code is lying to us. An available
3963   // externally function should have an equivalent function somewhere else,
3964   // but a function that calls itself through asm label/`__builtin_` trickery is
3965   // clearly not equivalent to the real implementation.
3966   // This happens in glibc's btowc and in some configure checks.
3967   return !isTriviallyRecursive(F);
3968 }
3969 
3970 bool CodeGenModule::shouldOpportunisticallyEmitVTables() {
3971   return CodeGenOpts.OptimizationLevel > 0;
3972 }
3973 
3974 void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
3975                                                        llvm::GlobalValue *GV) {
3976   const auto *FD = cast<FunctionDecl>(GD.getDecl());
3977 
3978   if (FD->isCPUSpecificMultiVersion()) {
3979     auto *Spec = FD->getAttr<CPUSpecificAttr>();
3980     for (unsigned I = 0; I < Spec->cpus_size(); ++I)
3981       EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
3982   } else if (FD->isTargetClonesMultiVersion()) {
3983     auto *Clone = FD->getAttr<TargetClonesAttr>();
3984     for (unsigned I = 0; I < Clone->featuresStrs_size(); ++I)
3985       if (Clone->isFirstOfVersion(I))
3986         EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
3987     // Ensure that the resolver function is also emitted.
3988     GetOrCreateMultiVersionResolver(GD);
3989   } else
3990     EmitGlobalFunctionDefinition(GD, GV);
3991 }
3992 
3993 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
3994   const auto *D = cast<ValueDecl>(GD.getDecl());
3995 
3996   PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
3997                                  Context.getSourceManager(),
3998                                  "Generating code for declaration");
3999 
4000   if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
4001     // At -O0, don't generate IR for functions with available_externally
4002     // linkage.
4003     if (!shouldEmitFunction(GD))
4004       return;
4005 
4006     llvm::TimeTraceScope TimeScope("CodeGen Function", [&]() {
4007       std::string Name;
4008       llvm::raw_string_ostream OS(Name);
4009       FD->getNameForDiagnostic(OS, getContext().getPrintingPolicy(),
4010                                /*Qualified=*/true);
4011       return Name;
4012     });
4013 
4014     if (const auto *Method = dyn_cast<CXXMethodDecl>(D)) {
4015       // Make sure to emit the definition(s) before we emit the thunks.
4016       // This is necessary for the generation of certain thunks.
4017       if (isa<CXXConstructorDecl>(Method) || isa<CXXDestructorDecl>(Method))
4018         ABI->emitCXXStructor(GD);
4019       else if (FD->isMultiVersion())
4020         EmitMultiVersionFunctionDefinition(GD, GV);
4021       else
4022         EmitGlobalFunctionDefinition(GD, GV);
4023 
4024       if (Method->isVirtual())
4025         getVTables().EmitThunks(GD);
4026 
4027       return;
4028     }
4029 
4030     if (FD->isMultiVersion())
4031       return EmitMultiVersionFunctionDefinition(GD, GV);
4032     return EmitGlobalFunctionDefinition(GD, GV);
4033   }
4034 
4035   if (const auto *VD = dyn_cast<VarDecl>(D))
4036     return EmitGlobalVarDefinition(VD, !VD->hasDefinition());
4037 
4038   llvm_unreachable("Invalid argument to EmitGlobalDefinition()");
4039 }
4040 
4041 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
4042                                                       llvm::Function *NewFn);
4043 
4044 static unsigned
4045 TargetMVPriority(const TargetInfo &TI,
4046                  const CodeGenFunction::MultiVersionResolverOption &RO) {
4047   unsigned Priority = 0;
4048   unsigned NumFeatures = 0;
4049   for (StringRef Feat : RO.Conditions.Features) {
4050     Priority = std::max(Priority, TI.multiVersionSortPriority(Feat));
4051     NumFeatures++;
4052   }
4053 
4054   if (!RO.Conditions.Architecture.empty())
4055     Priority = std::max(
4056         Priority, TI.multiVersionSortPriority(RO.Conditions.Architecture));
4057 
4058   Priority += TI.multiVersionFeatureCost() * NumFeatures;
4059 
4060   return Priority;
4061 }
4062 
4063 // Multiversion functions should be at most 'WeakODRLinkage' so that a different
4064 // TU can forward declare the function without causing problems.  Particularly
4065 // in the cases of CPUDispatch, this causes issues. This also makes sure we
4066 // work with internal linkage functions, so that the same function name can be
4067 // used with internal linkage in multiple TUs.
4068 llvm::GlobalValue::LinkageTypes getMultiversionLinkage(CodeGenModule &CGM,
4069                                                        GlobalDecl GD) {
4070   const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
4071   if (FD->getFormalLinkage() == Linkage::Internal)
4072     return llvm::GlobalValue::InternalLinkage;
4073   return llvm::GlobalValue::WeakODRLinkage;
4074 }
4075 
4076 void CodeGenModule::emitMultiVersionFunctions() {
4077   std::vector<GlobalDecl> MVFuncsToEmit;
4078   MultiVersionFuncs.swap(MVFuncsToEmit);
4079   for (GlobalDecl GD : MVFuncsToEmit) {
4080     const auto *FD = cast<FunctionDecl>(GD.getDecl());
4081     assert(FD && "Expected a FunctionDecl");
4082 
4083     SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
4084     if (FD->isTargetMultiVersion()) {
4085       getContext().forEachMultiversionedFunctionVersion(
4086           FD, [this, &GD, &Options](const FunctionDecl *CurFD) {
4087             GlobalDecl CurGD{
4088                 (CurFD->isDefined() ? CurFD->getDefinition() : CurFD)};
4089             StringRef MangledName = getMangledName(CurGD);
4090             llvm::Constant *Func = GetGlobalValue(MangledName);
4091             if (!Func) {
4092               if (CurFD->isDefined()) {
4093                 EmitGlobalFunctionDefinition(CurGD, nullptr);
4094                 Func = GetGlobalValue(MangledName);
4095               } else {
4096                 const CGFunctionInfo &FI =
4097                     getTypes().arrangeGlobalDeclaration(GD);
4098                 llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
4099                 Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
4100                                          /*DontDefer=*/false, ForDefinition);
4101               }
4102               assert(Func && "This should have just been created");
4103             }
4104             if (CurFD->getMultiVersionKind() == MultiVersionKind::Target) {
4105               const auto *TA = CurFD->getAttr<TargetAttr>();
4106               llvm::SmallVector<StringRef, 8> Feats;
4107               TA->getAddedFeatures(Feats);
4108               Options.emplace_back(cast<llvm::Function>(Func),
4109                                    TA->getArchitecture(), Feats);
4110             } else {
4111               const auto *TVA = CurFD->getAttr<TargetVersionAttr>();
4112               llvm::SmallVector<StringRef, 8> Feats;
4113               TVA->getFeatures(Feats);
4114               Options.emplace_back(cast<llvm::Function>(Func),
4115                                    /*Architecture*/ "", Feats);
4116             }
4117           });
4118     } else if (FD->isTargetClonesMultiVersion()) {
4119       const auto *TC = FD->getAttr<TargetClonesAttr>();
4120       for (unsigned VersionIndex = 0; VersionIndex < TC->featuresStrs_size();
4121            ++VersionIndex) {
4122         if (!TC->isFirstOfVersion(VersionIndex))
4123           continue;
4124         GlobalDecl CurGD{(FD->isDefined() ? FD->getDefinition() : FD),
4125                          VersionIndex};
4126         StringRef Version = TC->getFeatureStr(VersionIndex);
4127         StringRef MangledName = getMangledName(CurGD);
4128         llvm::Constant *Func = GetGlobalValue(MangledName);
4129         if (!Func) {
4130           if (FD->isDefined()) {
4131             EmitGlobalFunctionDefinition(CurGD, nullptr);
4132             Func = GetGlobalValue(MangledName);
4133           } else {
4134             const CGFunctionInfo &FI =
4135                 getTypes().arrangeGlobalDeclaration(CurGD);
4136             llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
4137             Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
4138                                      /*DontDefer=*/false, ForDefinition);
4139           }
4140           assert(Func && "This should have just been created");
4141         }
4142 
4143         StringRef Architecture;
4144         llvm::SmallVector<StringRef, 1> Feature;
4145 
4146         if (getTarget().getTriple().isAArch64()) {
4147           if (Version != "default") {
4148             llvm::SmallVector<StringRef, 8> VerFeats;
4149             Version.split(VerFeats, "+");
4150             for (auto &CurFeat : VerFeats)
4151               Feature.push_back(CurFeat.trim());
4152           }
4153         } else {
4154           if (Version.startswith("arch="))
4155             Architecture = Version.drop_front(sizeof("arch=") - 1);
4156           else if (Version != "default")
4157             Feature.push_back(Version);
4158         }
4159 
4160         Options.emplace_back(cast<llvm::Function>(Func), Architecture, Feature);
4161       }
4162     } else {
4163       assert(0 && "Expected a target or target_clones multiversion function");
4164       continue;
4165     }
4166 
4167     llvm::Constant *ResolverConstant = GetOrCreateMultiVersionResolver(GD);
4168     if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(ResolverConstant))
4169       ResolverConstant = IFunc->getResolver();
4170     llvm::Function *ResolverFunc = cast<llvm::Function>(ResolverConstant);
4171 
4172     ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
4173 
4174     if (!ResolverFunc->hasLocalLinkage() && supportsCOMDAT())
4175       ResolverFunc->setComdat(
4176           getModule().getOrInsertComdat(ResolverFunc->getName()));
4177 
4178     const TargetInfo &TI = getTarget();
4179     llvm::stable_sort(
4180         Options, [&TI](const CodeGenFunction::MultiVersionResolverOption &LHS,
4181                        const CodeGenFunction::MultiVersionResolverOption &RHS) {
4182           return TargetMVPriority(TI, LHS) > TargetMVPriority(TI, RHS);
4183         });
4184     CodeGenFunction CGF(*this);
4185     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
4186   }
4187 
4188   // Ensure that any additions to the deferred decls list caused by emitting a
4189   // variant are emitted.  This can happen when the variant itself is inline and
4190   // calls a function without linkage.
4191   if (!MVFuncsToEmit.empty())
4192     EmitDeferred();
4193 
4194   // Ensure that any additions to the multiversion funcs list from either the
4195   // deferred decls or the multiversion functions themselves are emitted.
4196   if (!MultiVersionFuncs.empty())
4197     emitMultiVersionFunctions();
4198 }
4199 
4200 void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
4201   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4202   assert(FD && "Not a FunctionDecl?");
4203   assert(FD->isCPUDispatchMultiVersion() && "Not a multiversion function?");
4204   const auto *DD = FD->getAttr<CPUDispatchAttr>();
4205   assert(DD && "Not a cpu_dispatch Function?");
4206 
4207   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4208   llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
4209 
4210   StringRef ResolverName = getMangledName(GD);
4211   UpdateMultiVersionNames(GD, FD, ResolverName);
4212 
4213   llvm::Type *ResolverType;
4214   GlobalDecl ResolverGD;
4215   if (getTarget().supportsIFunc()) {
4216     ResolverType = llvm::FunctionType::get(
4217         llvm::PointerType::get(DeclTy,
4218                                getTypes().getTargetAddressSpace(FD->getType())),
4219         false);
4220   }
4221   else {
4222     ResolverType = DeclTy;
4223     ResolverGD = GD;
4224   }
4225 
4226   auto *ResolverFunc = cast<llvm::Function>(GetOrCreateLLVMFunction(
4227       ResolverName, ResolverType, ResolverGD, /*ForVTable=*/false));
4228   ResolverFunc->setLinkage(getMultiversionLinkage(*this, GD));
4229   if (supportsCOMDAT())
4230     ResolverFunc->setComdat(
4231         getModule().getOrInsertComdat(ResolverFunc->getName()));
4232 
4233   SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
4234   const TargetInfo &Target = getTarget();
4235   unsigned Index = 0;
4236   for (const IdentifierInfo *II : DD->cpus()) {
4237     // Get the name of the target function so we can look it up/create it.
4238     std::string MangledName = getMangledNameImpl(*this, GD, FD, true) +
4239                               getCPUSpecificMangling(*this, II->getName());
4240 
4241     llvm::Constant *Func = GetGlobalValue(MangledName);
4242 
4243     if (!Func) {
4244       GlobalDecl ExistingDecl = Manglings.lookup(MangledName);
4245       if (ExistingDecl.getDecl() &&
4246           ExistingDecl.getDecl()->getAsFunction()->isDefined()) {
4247         EmitGlobalFunctionDefinition(ExistingDecl, nullptr);
4248         Func = GetGlobalValue(MangledName);
4249       } else {
4250         if (!ExistingDecl.getDecl())
4251           ExistingDecl = GD.getWithMultiVersionIndex(Index);
4252 
4253       Func = GetOrCreateLLVMFunction(
4254           MangledName, DeclTy, ExistingDecl,
4255           /*ForVTable=*/false, /*DontDefer=*/true,
4256           /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
4257       }
4258     }
4259 
4260     llvm::SmallVector<StringRef, 32> Features;
4261     Target.getCPUSpecificCPUDispatchFeatures(II->getName(), Features);
4262     llvm::transform(Features, Features.begin(),
4263                     [](StringRef Str) { return Str.substr(1); });
4264     llvm::erase_if(Features, [&Target](StringRef Feat) {
4265       return !Target.validateCpuSupports(Feat);
4266     });
4267     Options.emplace_back(cast<llvm::Function>(Func), StringRef{}, Features);
4268     ++Index;
4269   }
4270 
4271   llvm::stable_sort(
4272       Options, [](const CodeGenFunction::MultiVersionResolverOption &LHS,
4273                   const CodeGenFunction::MultiVersionResolverOption &RHS) {
4274         return llvm::X86::getCpuSupportsMask(LHS.Conditions.Features) >
4275                llvm::X86::getCpuSupportsMask(RHS.Conditions.Features);
4276       });
4277 
4278   // If the list contains multiple 'default' versions, such as when it contains
4279   // 'pentium' and 'generic', don't emit the call to the generic one (since we
4280   // always run on at least a 'pentium'). We do this by deleting the 'least
4281   // advanced' (read, lowest mangling letter).
4282   while (Options.size() > 1 &&
4283          llvm::all_of(llvm::X86::getCpuSupportsMask(
4284                           (Options.end() - 2)->Conditions.Features),
4285                       [](auto X) { return X == 0; })) {
4286     StringRef LHSName = (Options.end() - 2)->Function->getName();
4287     StringRef RHSName = (Options.end() - 1)->Function->getName();
4288     if (LHSName.compare(RHSName) < 0)
4289       Options.erase(Options.end() - 2);
4290     else
4291       Options.erase(Options.end() - 1);
4292   }
4293 
4294   CodeGenFunction CGF(*this);
4295   CGF.EmitMultiVersionResolver(ResolverFunc, Options);
4296 
4297   if (getTarget().supportsIFunc()) {
4298     llvm::GlobalValue::LinkageTypes Linkage = getMultiversionLinkage(*this, GD);
4299     auto *IFunc = cast<llvm::GlobalValue>(GetOrCreateMultiVersionResolver(GD));
4300 
4301     // Fix up function declarations that were created for cpu_specific before
4302     // cpu_dispatch was known
4303     if (!isa<llvm::GlobalIFunc>(IFunc)) {
4304       assert(cast<llvm::Function>(IFunc)->isDeclaration());
4305       auto *GI = llvm::GlobalIFunc::create(DeclTy, 0, Linkage, "", ResolverFunc,
4306                                            &getModule());
4307       GI->takeName(IFunc);
4308       IFunc->replaceAllUsesWith(GI);
4309       IFunc->eraseFromParent();
4310       IFunc = GI;
4311     }
4312 
4313     std::string AliasName = getMangledNameImpl(
4314         *this, GD, FD, /*OmitMultiVersionMangling=*/true);
4315     llvm::Constant *AliasFunc = GetGlobalValue(AliasName);
4316     if (!AliasFunc) {
4317       auto *GA = llvm::GlobalAlias::create(DeclTy, 0, Linkage, AliasName, IFunc,
4318                                            &getModule());
4319       SetCommonAttributes(GD, GA);
4320     }
4321   }
4322 }
4323 
4324 /// If a dispatcher for the specified mangled name is not in the module, create
4325 /// and return an llvm Function with the specified type.
4326 llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(GlobalDecl GD) {
4327   const auto *FD = cast<FunctionDecl>(GD.getDecl());
4328   assert(FD && "Not a FunctionDecl?");
4329 
4330   std::string MangledName =
4331       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
4332 
4333   // Holds the name of the resolver, in ifunc mode this is the ifunc (which has
4334   // a separate resolver).
4335   std::string ResolverName = MangledName;
4336   if (getTarget().supportsIFunc())
4337     ResolverName += ".ifunc";
4338   else if (FD->isTargetMultiVersion())
4339     ResolverName += ".resolver";
4340 
4341   // If the resolver has already been created, just return it.
4342   if (llvm::GlobalValue *ResolverGV = GetGlobalValue(ResolverName))
4343     return ResolverGV;
4344 
4345   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4346   llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
4347 
4348   // The resolver needs to be created. For target and target_clones, defer
4349   // creation until the end of the TU.
4350   if (FD->isTargetMultiVersion() || FD->isTargetClonesMultiVersion())
4351     MultiVersionFuncs.push_back(GD);
4352 
4353   // For cpu_specific, don't create an ifunc yet because we don't know if the
4354   // cpu_dispatch will be emitted in this translation unit.
4355   if (getTarget().supportsIFunc() && !FD->isCPUSpecificMultiVersion()) {
4356     llvm::Type *ResolverType = llvm::FunctionType::get(
4357         llvm::PointerType::get(DeclTy,
4358                                getTypes().getTargetAddressSpace(FD->getType())),
4359         false);
4360     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
4361         MangledName + ".resolver", ResolverType, GlobalDecl{},
4362         /*ForVTable=*/false);
4363     llvm::GlobalIFunc *GIF =
4364         llvm::GlobalIFunc::create(DeclTy, 0, getMultiversionLinkage(*this, GD),
4365                                   "", Resolver, &getModule());
4366     GIF->setName(ResolverName);
4367     SetCommonAttributes(FD, GIF);
4368 
4369     return GIF;
4370   }
4371 
4372   llvm::Constant *Resolver = GetOrCreateLLVMFunction(
4373       ResolverName, DeclTy, GlobalDecl{}, /*ForVTable=*/false);
4374   assert(isa<llvm::GlobalValue>(Resolver) &&
4375          "Resolver should be created for the first time");
4376   SetCommonAttributes(FD, cast<llvm::GlobalValue>(Resolver));
4377   return Resolver;
4378 }
4379 
4380 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the
4381 /// module, create and return an llvm Function with the specified type. If there
4382 /// is something in the module with the specified name, return it potentially
4383 /// bitcasted to the right type.
4384 ///
4385 /// If D is non-null, it specifies a decl that correspond to this.  This is used
4386 /// to set the attributes on the function when it is first created.
4387 llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
4388     StringRef MangledName, llvm::Type *Ty, GlobalDecl GD, bool ForVTable,
4389     bool DontDefer, bool IsThunk, llvm::AttributeList ExtraAttrs,
4390     ForDefinition_t IsForDefinition) {
4391   const Decl *D = GD.getDecl();
4392 
4393   // Any attempts to use a MultiVersion function should result in retrieving
4394   // the iFunc instead. Name Mangling will handle the rest of the changes.
4395   if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D)) {
4396     // For the device mark the function as one that should be emitted.
4397     if (getLangOpts().OpenMPIsTargetDevice && OpenMPRuntime &&
4398         !OpenMPRuntime->markAsGlobalTarget(GD) && FD->isDefined() &&
4399         !DontDefer && !IsForDefinition) {
4400       if (const FunctionDecl *FDDef = FD->getDefinition()) {
4401         GlobalDecl GDDef;
4402         if (const auto *CD = dyn_cast<CXXConstructorDecl>(FDDef))
4403           GDDef = GlobalDecl(CD, GD.getCtorType());
4404         else if (const auto *DD = dyn_cast<CXXDestructorDecl>(FDDef))
4405           GDDef = GlobalDecl(DD, GD.getDtorType());
4406         else
4407           GDDef = GlobalDecl(FDDef);
4408         EmitGlobal(GDDef);
4409       }
4410     }
4411 
4412     if (FD->isMultiVersion()) {
4413       UpdateMultiVersionNames(GD, FD, MangledName);
4414       if (!IsForDefinition)
4415         return GetOrCreateMultiVersionResolver(GD);
4416     }
4417   }
4418 
4419   // Lookup the entry, lazily creating it if necessary.
4420   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4421   if (Entry) {
4422     if (WeakRefReferences.erase(Entry)) {
4423       const FunctionDecl *FD = cast_or_null<FunctionDecl>(D);
4424       if (FD && !FD->hasAttr<WeakAttr>())
4425         Entry->setLinkage(llvm::Function::ExternalLinkage);
4426     }
4427 
4428     // Handle dropped DLL attributes.
4429     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
4430         !shouldMapVisibilityToDLLExport(cast_or_null<NamedDecl>(D))) {
4431       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
4432       setDSOLocal(Entry);
4433     }
4434 
4435     // If there are two attempts to define the same mangled name, issue an
4436     // error.
4437     if (IsForDefinition && !Entry->isDeclaration()) {
4438       GlobalDecl OtherGD;
4439       // Check that GD is not yet in DiagnosedConflictingDefinitions is required
4440       // to make sure that we issue an error only once.
4441       if (lookupRepresentativeDecl(MangledName, OtherGD) &&
4442           (GD.getCanonicalDecl().getDecl() !=
4443            OtherGD.getCanonicalDecl().getDecl()) &&
4444           DiagnosedConflictingDefinitions.insert(GD).second) {
4445         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
4446             << MangledName;
4447         getDiags().Report(OtherGD.getDecl()->getLocation(),
4448                           diag::note_previous_definition);
4449       }
4450     }
4451 
4452     if ((isa<llvm::Function>(Entry) || isa<llvm::GlobalAlias>(Entry)) &&
4453         (Entry->getValueType() == Ty)) {
4454       return Entry;
4455     }
4456 
4457     // Make sure the result is of the correct type.
4458     // (If function is requested for a definition, we always need to create a new
4459     // function, not just return a bitcast.)
4460     if (!IsForDefinition)
4461       return Entry;
4462   }
4463 
4464   // This function doesn't have a complete type (for example, the return
4465   // type is an incomplete struct). Use a fake type instead, and make
4466   // sure not to try to set attributes.
4467   bool IsIncompleteFunction = false;
4468 
4469   llvm::FunctionType *FTy;
4470   if (isa<llvm::FunctionType>(Ty)) {
4471     FTy = cast<llvm::FunctionType>(Ty);
4472   } else {
4473     FTy = llvm::FunctionType::get(VoidTy, false);
4474     IsIncompleteFunction = true;
4475   }
4476 
4477   llvm::Function *F =
4478       llvm::Function::Create(FTy, llvm::Function::ExternalLinkage,
4479                              Entry ? StringRef() : MangledName, &getModule());
4480 
4481   // Store the declaration associated with this function so it is potentially
4482   // updated by further declarations or definitions and emitted at the end.
4483   if (D && D->hasAttr<AnnotateAttr>())
4484     DeferredAnnotations[MangledName] = cast<ValueDecl>(D);
4485 
4486   // If we already created a function with the same mangled name (but different
4487   // type) before, take its name and add it to the list of functions to be
4488   // replaced with F at the end of CodeGen.
4489   //
4490   // This happens if there is a prototype for a function (e.g. "int f()") and
4491   // then a definition of a different type (e.g. "int f(int x)").
4492   if (Entry) {
4493     F->takeName(Entry);
4494 
4495     // This might be an implementation of a function without a prototype, in
4496     // which case, try to do special replacement of calls which match the new
4497     // prototype.  The really key thing here is that we also potentially drop
4498     // arguments from the call site so as to make a direct call, which makes the
4499     // inliner happier and suppresses a number of optimizer warnings (!) about
4500     // dropping arguments.
4501     if (!Entry->use_empty()) {
4502       ReplaceUsesOfNonProtoTypeWithRealFunction(Entry, F);
4503       Entry->removeDeadConstantUsers();
4504     }
4505 
4506     addGlobalValReplacement(Entry, F);
4507   }
4508 
4509   assert(F->getName() == MangledName && "name was uniqued!");
4510   if (D)
4511     SetFunctionAttributes(GD, F, IsIncompleteFunction, IsThunk);
4512   if (ExtraAttrs.hasFnAttrs()) {
4513     llvm::AttrBuilder B(F->getContext(), ExtraAttrs.getFnAttrs());
4514     F->addFnAttrs(B);
4515   }
4516 
4517   if (!DontDefer) {
4518     // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
4519     // each other bottoming out with the base dtor.  Therefore we emit non-base
4520     // dtors on usage, even if there is no dtor definition in the TU.
4521     if (isa_and_nonnull<CXXDestructorDecl>(D) &&
4522         getCXXABI().useThunkForDtorVariant(cast<CXXDestructorDecl>(D),
4523                                            GD.getDtorType()))
4524       addDeferredDeclToEmit(GD);
4525 
4526     // This is the first use or definition of a mangled name.  If there is a
4527     // deferred decl with this name, remember that we need to emit it at the end
4528     // of the file.
4529     auto DDI = DeferredDecls.find(MangledName);
4530     if (DDI != DeferredDecls.end()) {
4531       // Move the potentially referenced deferred decl to the
4532       // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
4533       // don't need it anymore).
4534       addDeferredDeclToEmit(DDI->second);
4535       DeferredDecls.erase(DDI);
4536 
4537       // Otherwise, there are cases we have to worry about where we're
4538       // using a declaration for which we must emit a definition but where
4539       // we might not find a top-level definition:
4540       //   - member functions defined inline in their classes
4541       //   - friend functions defined inline in some class
4542       //   - special member functions with implicit definitions
4543       // If we ever change our AST traversal to walk into class methods,
4544       // this will be unnecessary.
4545       //
4546       // We also don't emit a definition for a function if it's going to be an
4547       // entry in a vtable, unless it's already marked as used.
4548     } else if (getLangOpts().CPlusPlus && D) {
4549       // Look for a declaration that's lexically in a record.
4550       for (const auto *FD = cast<FunctionDecl>(D)->getMostRecentDecl(); FD;
4551            FD = FD->getPreviousDecl()) {
4552         if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
4553           if (FD->doesThisDeclarationHaveABody()) {
4554             addDeferredDeclToEmit(GD.getWithDecl(FD));
4555             break;
4556           }
4557         }
4558       }
4559     }
4560   }
4561 
4562   // Make sure the result is of the requested type.
4563   if (!IsIncompleteFunction) {
4564     assert(F->getFunctionType() == Ty);
4565     return F;
4566   }
4567 
4568   return F;
4569 }
4570 
4571 /// GetAddrOfFunction - Return the address of the given function.  If Ty is
4572 /// non-null, then this function will use the specified type if it has to
4573 /// create it (this occurs when we see a definition of the function).
4574 llvm::Constant *
4575 CodeGenModule::GetAddrOfFunction(GlobalDecl GD, llvm::Type *Ty, bool ForVTable,
4576                                  bool DontDefer,
4577                                  ForDefinition_t IsForDefinition) {
4578   // If there was no specific requested type, just convert it now.
4579   if (!Ty) {
4580     const auto *FD = cast<FunctionDecl>(GD.getDecl());
4581     Ty = getTypes().ConvertType(FD->getType());
4582   }
4583 
4584   // Devirtualized destructor calls may come through here instead of via
4585   // getAddrOfCXXStructor. Make sure we use the MS ABI base destructor instead
4586   // of the complete destructor when necessary.
4587   if (const auto *DD = dyn_cast<CXXDestructorDecl>(GD.getDecl())) {
4588     if (getTarget().getCXXABI().isMicrosoft() &&
4589         GD.getDtorType() == Dtor_Complete &&
4590         DD->getParent()->getNumVBases() == 0)
4591       GD = GlobalDecl(DD, Dtor_Base);
4592   }
4593 
4594   StringRef MangledName = getMangledName(GD);
4595   auto *F = GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
4596                                     /*IsThunk=*/false, llvm::AttributeList(),
4597                                     IsForDefinition);
4598   // Returns kernel handle for HIP kernel stub function.
4599   if (LangOpts.CUDA && !LangOpts.CUDAIsDevice &&
4600       cast<FunctionDecl>(GD.getDecl())->hasAttr<CUDAGlobalAttr>()) {
4601     auto *Handle = getCUDARuntime().getKernelHandle(
4602         cast<llvm::Function>(F->stripPointerCasts()), GD);
4603     if (IsForDefinition)
4604       return F;
4605     return Handle;
4606   }
4607   return F;
4608 }
4609 
4610 llvm::Constant *CodeGenModule::GetFunctionStart(const ValueDecl *Decl) {
4611   llvm::GlobalValue *F =
4612       cast<llvm::GlobalValue>(GetAddrOfFunction(Decl)->stripPointerCasts());
4613 
4614   return llvm::NoCFIValue::get(F);
4615 }
4616 
4617 static const FunctionDecl *
4618 GetRuntimeFunctionDecl(ASTContext &C, StringRef Name) {
4619   TranslationUnitDecl *TUDecl = C.getTranslationUnitDecl();
4620   DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
4621 
4622   IdentifierInfo &CII = C.Idents.get(Name);
4623   for (const auto *Result : DC->lookup(&CII))
4624     if (const auto *FD = dyn_cast<FunctionDecl>(Result))
4625       return FD;
4626 
4627   if (!C.getLangOpts().CPlusPlus)
4628     return nullptr;
4629 
4630   // Demangle the premangled name from getTerminateFn()
4631   IdentifierInfo &CXXII =
4632       (Name == "_ZSt9terminatev" || Name == "?terminate@@YAXXZ")
4633           ? C.Idents.get("terminate")
4634           : C.Idents.get(Name);
4635 
4636   for (const auto &N : {"__cxxabiv1", "std"}) {
4637     IdentifierInfo &NS = C.Idents.get(N);
4638     for (const auto *Result : DC->lookup(&NS)) {
4639       const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(Result);
4640       if (auto *LSD = dyn_cast<LinkageSpecDecl>(Result))
4641         for (const auto *Result : LSD->lookup(&NS))
4642           if ((ND = dyn_cast<NamespaceDecl>(Result)))
4643             break;
4644 
4645       if (ND)
4646         for (const auto *Result : ND->lookup(&CXXII))
4647           if (const auto *FD = dyn_cast<FunctionDecl>(Result))
4648             return FD;
4649     }
4650   }
4651 
4652   return nullptr;
4653 }
4654 
4655 /// CreateRuntimeFunction - Create a new runtime function with the specified
4656 /// type and name.
4657 llvm::FunctionCallee
4658 CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
4659                                      llvm::AttributeList ExtraAttrs, bool Local,
4660                                      bool AssumeConvergent) {
4661   if (AssumeConvergent) {
4662     ExtraAttrs =
4663         ExtraAttrs.addFnAttribute(VMContext, llvm::Attribute::Convergent);
4664   }
4665 
4666   llvm::Constant *C =
4667       GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(), /*ForVTable=*/false,
4668                               /*DontDefer=*/false, /*IsThunk=*/false,
4669                               ExtraAttrs);
4670 
4671   if (auto *F = dyn_cast<llvm::Function>(C)) {
4672     if (F->empty()) {
4673       F->setCallingConv(getRuntimeCC());
4674 
4675       // In Windows Itanium environments, try to mark runtime functions
4676       // dllimport. For Mingw and MSVC, don't. We don't really know if the user
4677       // will link their standard library statically or dynamically. Marking
4678       // functions imported when they are not imported can cause linker errors
4679       // and warnings.
4680       if (!Local && getTriple().isWindowsItaniumEnvironment() &&
4681           !getCodeGenOpts().LTOVisibilityPublicStd) {
4682         const FunctionDecl *FD = GetRuntimeFunctionDecl(Context, Name);
4683         if (!FD || FD->hasAttr<DLLImportAttr>()) {
4684           F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
4685           F->setLinkage(llvm::GlobalValue::ExternalLinkage);
4686         }
4687       }
4688       setDSOLocal(F);
4689     }
4690   }
4691 
4692   return {FTy, C};
4693 }
4694 
4695 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
4696 /// create and return an llvm GlobalVariable with the specified type and address
4697 /// space. If there is something in the module with the specified name, return
4698 /// it potentially bitcasted to the right type.
4699 ///
4700 /// If D is non-null, it specifies a decl that correspond to this.  This is used
4701 /// to set the attributes on the global when it is first created.
4702 ///
4703 /// If IsForDefinition is true, it is guaranteed that an actual global with
4704 /// type Ty will be returned, not conversion of a variable with the same
4705 /// mangled name but some other type.
4706 llvm::Constant *
4707 CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName, llvm::Type *Ty,
4708                                      LangAS AddrSpace, const VarDecl *D,
4709                                      ForDefinition_t IsForDefinition) {
4710   // Lookup the entry, lazily creating it if necessary.
4711   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4712   unsigned TargetAS = getContext().getTargetAddressSpace(AddrSpace);
4713   if (Entry) {
4714     if (WeakRefReferences.erase(Entry)) {
4715       if (D && !D->hasAttr<WeakAttr>())
4716         Entry->setLinkage(llvm::Function::ExternalLinkage);
4717     }
4718 
4719     // Handle dropped DLL attributes.
4720     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>() &&
4721         !shouldMapVisibilityToDLLExport(D))
4722       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
4723 
4724     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd && D)
4725       getOpenMPRuntime().registerTargetGlobalVariable(D, Entry);
4726 
4727     if (Entry->getValueType() == Ty && Entry->getAddressSpace() == TargetAS)
4728       return Entry;
4729 
4730     // If there are two attempts to define the same mangled name, issue an
4731     // error.
4732     if (IsForDefinition && !Entry->isDeclaration()) {
4733       GlobalDecl OtherGD;
4734       const VarDecl *OtherD;
4735 
4736       // Check that D is not yet in DiagnosedConflictingDefinitions is required
4737       // to make sure that we issue an error only once.
4738       if (D && lookupRepresentativeDecl(MangledName, OtherGD) &&
4739           (D->getCanonicalDecl() != OtherGD.getCanonicalDecl().getDecl()) &&
4740           (OtherD = dyn_cast<VarDecl>(OtherGD.getDecl())) &&
4741           OtherD->hasInit() &&
4742           DiagnosedConflictingDefinitions.insert(D).second) {
4743         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
4744             << MangledName;
4745         getDiags().Report(OtherGD.getDecl()->getLocation(),
4746                           diag::note_previous_definition);
4747       }
4748     }
4749 
4750     // Make sure the result is of the correct type.
4751     if (Entry->getType()->getAddressSpace() != TargetAS)
4752       return llvm::ConstantExpr::getAddrSpaceCast(
4753           Entry, llvm::PointerType::get(Ty->getContext(), TargetAS));
4754 
4755     // (If global is requested for a definition, we always need to create a new
4756     // global, not just return a bitcast.)
4757     if (!IsForDefinition)
4758       return Entry;
4759   }
4760 
4761   auto DAddrSpace = GetGlobalVarAddressSpace(D);
4762 
4763   auto *GV = new llvm::GlobalVariable(
4764       getModule(), Ty, false, llvm::GlobalValue::ExternalLinkage, nullptr,
4765       MangledName, nullptr, llvm::GlobalVariable::NotThreadLocal,
4766       getContext().getTargetAddressSpace(DAddrSpace));
4767 
4768   // If we already created a global with the same mangled name (but different
4769   // type) before, take its name and remove it from its parent.
4770   if (Entry) {
4771     GV->takeName(Entry);
4772 
4773     if (!Entry->use_empty()) {
4774       Entry->replaceAllUsesWith(GV);
4775     }
4776 
4777     Entry->eraseFromParent();
4778   }
4779 
4780   // This is the first use or definition of a mangled name.  If there is a
4781   // deferred decl with this name, remember that we need to emit it at the end
4782   // of the file.
4783   auto DDI = DeferredDecls.find(MangledName);
4784   if (DDI != DeferredDecls.end()) {
4785     // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
4786     // list, and remove it from DeferredDecls (since we don't need it anymore).
4787     addDeferredDeclToEmit(DDI->second);
4788     DeferredDecls.erase(DDI);
4789   }
4790 
4791   // Handle things which are present even on external declarations.
4792   if (D) {
4793     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd)
4794       getOpenMPRuntime().registerTargetGlobalVariable(D, GV);
4795 
4796     // FIXME: This code is overly simple and should be merged with other global
4797     // handling.
4798     GV->setConstant(D->getType().isConstantStorage(getContext(), false, false));
4799 
4800     GV->setAlignment(getContext().getDeclAlign(D).getAsAlign());
4801 
4802     setLinkageForGV(GV, D);
4803 
4804     if (D->getTLSKind()) {
4805       if (D->getTLSKind() == VarDecl::TLS_Dynamic)
4806         CXXThreadLocals.push_back(D);
4807       setTLSMode(GV, *D);
4808     }
4809 
4810     setGVProperties(GV, D);
4811 
4812     // If required by the ABI, treat declarations of static data members with
4813     // inline initializers as definitions.
4814     if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
4815       EmitGlobalVarDefinition(D);
4816     }
4817 
4818     // Emit section information for extern variables.
4819     if (D->hasExternalStorage()) {
4820       if (const SectionAttr *SA = D->getAttr<SectionAttr>())
4821         GV->setSection(SA->getName());
4822     }
4823 
4824     // Handle XCore specific ABI requirements.
4825     if (getTriple().getArch() == llvm::Triple::xcore &&
4826         D->getLanguageLinkage() == CLanguageLinkage &&
4827         D->getType().isConstant(Context) &&
4828         isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
4829       GV->setSection(".cp.rodata");
4830 
4831     // Check if we a have a const declaration with an initializer, we may be
4832     // able to emit it as available_externally to expose it's value to the
4833     // optimizer.
4834     if (Context.getLangOpts().CPlusPlus && GV->hasExternalLinkage() &&
4835         D->getType().isConstQualified() && !GV->hasInitializer() &&
4836         !D->hasDefinition() && D->hasInit() && !D->hasAttr<DLLImportAttr>()) {
4837       const auto *Record =
4838           Context.getBaseElementType(D->getType())->getAsCXXRecordDecl();
4839       bool HasMutableFields = Record && Record->hasMutableFields();
4840       if (!HasMutableFields) {
4841         const VarDecl *InitDecl;
4842         const Expr *InitExpr = D->getAnyInitializer(InitDecl);
4843         if (InitExpr) {
4844           ConstantEmitter emitter(*this);
4845           llvm::Constant *Init = emitter.tryEmitForInitializer(*InitDecl);
4846           if (Init) {
4847             auto *InitType = Init->getType();
4848             if (GV->getValueType() != InitType) {
4849               // The type of the initializer does not match the definition.
4850               // This happens when an initializer has a different type from
4851               // the type of the global (because of padding at the end of a
4852               // structure for instance).
4853               GV->setName(StringRef());
4854               // Make a new global with the correct type, this is now guaranteed
4855               // to work.
4856               auto *NewGV = cast<llvm::GlobalVariable>(
4857                   GetAddrOfGlobalVar(D, InitType, IsForDefinition)
4858                       ->stripPointerCasts());
4859 
4860               // Erase the old global, since it is no longer used.
4861               GV->eraseFromParent();
4862               GV = NewGV;
4863             } else {
4864               GV->setInitializer(Init);
4865               GV->setConstant(true);
4866               GV->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
4867             }
4868             emitter.finalize(GV);
4869           }
4870         }
4871       }
4872     }
4873   }
4874 
4875   if (D &&
4876       D->isThisDeclarationADefinition(Context) == VarDecl::DeclarationOnly) {
4877     getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
4878     // External HIP managed variables needed to be recorded for transformation
4879     // in both device and host compilations.
4880     if (getLangOpts().CUDA && D && D->hasAttr<HIPManagedAttr>() &&
4881         D->hasExternalStorage())
4882       getCUDARuntime().handleVarRegistration(D, *GV);
4883   }
4884 
4885   if (D)
4886     SanitizerMD->reportGlobal(GV, *D);
4887 
4888   LangAS ExpectedAS =
4889       D ? D->getType().getAddressSpace()
4890         : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
4891   assert(getContext().getTargetAddressSpace(ExpectedAS) == TargetAS);
4892   if (DAddrSpace != ExpectedAS) {
4893     return getTargetCodeGenInfo().performAddrSpaceCast(
4894         *this, GV, DAddrSpace, ExpectedAS,
4895         llvm::PointerType::get(getLLVMContext(), TargetAS));
4896   }
4897 
4898   return GV;
4899 }
4900 
4901 llvm::Constant *
4902 CodeGenModule::GetAddrOfGlobal(GlobalDecl GD, ForDefinition_t IsForDefinition) {
4903   const Decl *D = GD.getDecl();
4904 
4905   if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D))
4906     return getAddrOfCXXStructor(GD, /*FnInfo=*/nullptr, /*FnType=*/nullptr,
4907                                 /*DontDefer=*/false, IsForDefinition);
4908 
4909   if (isa<CXXMethodDecl>(D)) {
4910     auto FInfo =
4911         &getTypes().arrangeCXXMethodDeclaration(cast<CXXMethodDecl>(D));
4912     auto Ty = getTypes().GetFunctionType(*FInfo);
4913     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
4914                              IsForDefinition);
4915   }
4916 
4917   if (isa<FunctionDecl>(D)) {
4918     const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4919     llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
4920     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
4921                              IsForDefinition);
4922   }
4923 
4924   return GetAddrOfGlobalVar(cast<VarDecl>(D), /*Ty=*/nullptr, IsForDefinition);
4925 }
4926 
4927 llvm::GlobalVariable *CodeGenModule::CreateOrReplaceCXXRuntimeVariable(
4928     StringRef Name, llvm::Type *Ty, llvm::GlobalValue::LinkageTypes Linkage,
4929     llvm::Align Alignment) {
4930   llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name);
4931   llvm::GlobalVariable *OldGV = nullptr;
4932 
4933   if (GV) {
4934     // Check if the variable has the right type.
4935     if (GV->getValueType() == Ty)
4936       return GV;
4937 
4938     // Because C++ name mangling, the only way we can end up with an already
4939     // existing global with the same name is if it has been declared extern "C".
4940     assert(GV->isDeclaration() && "Declaration has wrong type!");
4941     OldGV = GV;
4942   }
4943 
4944   // Create a new variable.
4945   GV = new llvm::GlobalVariable(getModule(), Ty, /*isConstant=*/true,
4946                                 Linkage, nullptr, Name);
4947 
4948   if (OldGV) {
4949     // Replace occurrences of the old variable if needed.
4950     GV->takeName(OldGV);
4951 
4952     if (!OldGV->use_empty()) {
4953       OldGV->replaceAllUsesWith(GV);
4954     }
4955 
4956     OldGV->eraseFromParent();
4957   }
4958 
4959   if (supportsCOMDAT() && GV->isWeakForLinker() &&
4960       !GV->hasAvailableExternallyLinkage())
4961     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
4962 
4963   GV->setAlignment(Alignment);
4964 
4965   return GV;
4966 }
4967 
4968 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
4969 /// given global variable.  If Ty is non-null and if the global doesn't exist,
4970 /// then it will be created with the specified type instead of whatever the
4971 /// normal requested type would be. If IsForDefinition is true, it is guaranteed
4972 /// that an actual global with type Ty will be returned, not conversion of a
4973 /// variable with the same mangled name but some other type.
4974 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
4975                                                   llvm::Type *Ty,
4976                                            ForDefinition_t IsForDefinition) {
4977   assert(D->hasGlobalStorage() && "Not a global variable");
4978   QualType ASTTy = D->getType();
4979   if (!Ty)
4980     Ty = getTypes().ConvertTypeForMem(ASTTy);
4981 
4982   StringRef MangledName = getMangledName(D);
4983   return GetOrCreateLLVMGlobal(MangledName, Ty, ASTTy.getAddressSpace(), D,
4984                                IsForDefinition);
4985 }
4986 
4987 /// CreateRuntimeVariable - Create a new runtime global variable with the
4988 /// specified type and name.
4989 llvm::Constant *
4990 CodeGenModule::CreateRuntimeVariable(llvm::Type *Ty,
4991                                      StringRef Name) {
4992   LangAS AddrSpace = getContext().getLangOpts().OpenCL ? LangAS::opencl_global
4993                                                        : LangAS::Default;
4994   auto *Ret = GetOrCreateLLVMGlobal(Name, Ty, AddrSpace, nullptr);
4995   setDSOLocal(cast<llvm::GlobalValue>(Ret->stripPointerCasts()));
4996   return Ret;
4997 }
4998 
4999 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
5000   assert(!D->getInit() && "Cannot emit definite definitions here!");
5001 
5002   StringRef MangledName = getMangledName(D);
5003   llvm::GlobalValue *GV = GetGlobalValue(MangledName);
5004 
5005   // We already have a definition, not declaration, with the same mangled name.
5006   // Emitting of declaration is not required (and actually overwrites emitted
5007   // definition).
5008   if (GV && !GV->isDeclaration())
5009     return;
5010 
5011   // If we have not seen a reference to this variable yet, place it into the
5012   // deferred declarations table to be emitted if needed later.
5013   if (!MustBeEmitted(D) && !GV) {
5014       DeferredDecls[MangledName] = D;
5015       return;
5016   }
5017 
5018   // The tentative definition is the only definition.
5019   EmitGlobalVarDefinition(D);
5020 }
5021 
5022 void CodeGenModule::EmitExternalDeclaration(const VarDecl *D) {
5023   EmitExternalVarDeclaration(D);
5024 }
5025 
5026 CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const {
5027   return Context.toCharUnitsFromBits(
5028       getDataLayout().getTypeStoreSizeInBits(Ty));
5029 }
5030 
5031 LangAS CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
5032   if (LangOpts.OpenCL) {
5033     LangAS AS = D ? D->getType().getAddressSpace() : LangAS::opencl_global;
5034     assert(AS == LangAS::opencl_global ||
5035            AS == LangAS::opencl_global_device ||
5036            AS == LangAS::opencl_global_host ||
5037            AS == LangAS::opencl_constant ||
5038            AS == LangAS::opencl_local ||
5039            AS >= LangAS::FirstTargetAddressSpace);
5040     return AS;
5041   }
5042 
5043   if (LangOpts.SYCLIsDevice &&
5044       (!D || D->getType().getAddressSpace() == LangAS::Default))
5045     return LangAS::sycl_global;
5046 
5047   if (LangOpts.CUDA && LangOpts.CUDAIsDevice) {
5048     if (D) {
5049       if (D->hasAttr<CUDAConstantAttr>())
5050         return LangAS::cuda_constant;
5051       if (D->hasAttr<CUDASharedAttr>())
5052         return LangAS::cuda_shared;
5053       if (D->hasAttr<CUDADeviceAttr>())
5054         return LangAS::cuda_device;
5055       if (D->getType().isConstQualified())
5056         return LangAS::cuda_constant;
5057     }
5058     return LangAS::cuda_device;
5059   }
5060 
5061   if (LangOpts.OpenMP) {
5062     LangAS AS;
5063     if (OpenMPRuntime->hasAllocateAttributeForGlobalVar(D, AS))
5064       return AS;
5065   }
5066   return getTargetCodeGenInfo().getGlobalVarAddressSpace(*this, D);
5067 }
5068 
5069 LangAS CodeGenModule::GetGlobalConstantAddressSpace() const {
5070   // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
5071   if (LangOpts.OpenCL)
5072     return LangAS::opencl_constant;
5073   if (LangOpts.SYCLIsDevice)
5074     return LangAS::sycl_global;
5075   if (LangOpts.HIP && LangOpts.CUDAIsDevice && getTriple().isSPIRV())
5076     // For HIPSPV map literals to cuda_device (maps to CrossWorkGroup in SPIR-V)
5077     // instead of default AS (maps to Generic in SPIR-V). Otherwise, we end up
5078     // with OpVariable instructions with Generic storage class which is not
5079     // allowed (SPIR-V V1.6 s3.42.8). Also, mapping literals to SPIR-V
5080     // UniformConstant storage class is not viable as pointers to it may not be
5081     // casted to Generic pointers which are used to model HIP's "flat" pointers.
5082     return LangAS::cuda_device;
5083   if (auto AS = getTarget().getConstantAddressSpace())
5084     return *AS;
5085   return LangAS::Default;
5086 }
5087 
5088 // In address space agnostic languages, string literals are in default address
5089 // space in AST. However, certain targets (e.g. amdgcn) request them to be
5090 // emitted in constant address space in LLVM IR. To be consistent with other
5091 // parts of AST, string literal global variables in constant address space
5092 // need to be casted to default address space before being put into address
5093 // map and referenced by other part of CodeGen.
5094 // In OpenCL, string literals are in constant address space in AST, therefore
5095 // they should not be casted to default address space.
5096 static llvm::Constant *
5097 castStringLiteralToDefaultAddressSpace(CodeGenModule &CGM,
5098                                        llvm::GlobalVariable *GV) {
5099   llvm::Constant *Cast = GV;
5100   if (!CGM.getLangOpts().OpenCL) {
5101     auto AS = CGM.GetGlobalConstantAddressSpace();
5102     if (AS != LangAS::Default)
5103       Cast = CGM.getTargetCodeGenInfo().performAddrSpaceCast(
5104           CGM, GV, AS, LangAS::Default,
5105           llvm::PointerType::get(
5106               CGM.getLLVMContext(),
5107               CGM.getContext().getTargetAddressSpace(LangAS::Default)));
5108   }
5109   return Cast;
5110 }
5111 
5112 template<typename SomeDecl>
5113 void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D,
5114                                                llvm::GlobalValue *GV) {
5115   if (!getLangOpts().CPlusPlus)
5116     return;
5117 
5118   // Must have 'used' attribute, or else inline assembly can't rely on
5119   // the name existing.
5120   if (!D->template hasAttr<UsedAttr>())
5121     return;
5122 
5123   // Must have internal linkage and an ordinary name.
5124   if (!D->getIdentifier() || D->getFormalLinkage() != Linkage::Internal)
5125     return;
5126 
5127   // Must be in an extern "C" context. Entities declared directly within
5128   // a record are not extern "C" even if the record is in such a context.
5129   const SomeDecl *First = D->getFirstDecl();
5130   if (First->getDeclContext()->isRecord() || !First->isInExternCContext())
5131     return;
5132 
5133   // OK, this is an internal linkage entity inside an extern "C" linkage
5134   // specification. Make a note of that so we can give it the "expected"
5135   // mangled name if nothing else is using that name.
5136   std::pair<StaticExternCMap::iterator, bool> R =
5137       StaticExternCValues.insert(std::make_pair(D->getIdentifier(), GV));
5138 
5139   // If we have multiple internal linkage entities with the same name
5140   // in extern "C" regions, none of them gets that name.
5141   if (!R.second)
5142     R.first->second = nullptr;
5143 }
5144 
5145 static bool shouldBeInCOMDAT(CodeGenModule &CGM, const Decl &D) {
5146   if (!CGM.supportsCOMDAT())
5147     return false;
5148 
5149   if (D.hasAttr<SelectAnyAttr>())
5150     return true;
5151 
5152   GVALinkage Linkage;
5153   if (auto *VD = dyn_cast<VarDecl>(&D))
5154     Linkage = CGM.getContext().GetGVALinkageForVariable(VD);
5155   else
5156     Linkage = CGM.getContext().GetGVALinkageForFunction(cast<FunctionDecl>(&D));
5157 
5158   switch (Linkage) {
5159   case GVA_Internal:
5160   case GVA_AvailableExternally:
5161   case GVA_StrongExternal:
5162     return false;
5163   case GVA_DiscardableODR:
5164   case GVA_StrongODR:
5165     return true;
5166   }
5167   llvm_unreachable("No such linkage");
5168 }
5169 
5170 bool CodeGenModule::supportsCOMDAT() const {
5171   return getTriple().supportsCOMDAT();
5172 }
5173 
5174 void CodeGenModule::maybeSetTrivialComdat(const Decl &D,
5175                                           llvm::GlobalObject &GO) {
5176   if (!shouldBeInCOMDAT(*this, D))
5177     return;
5178   GO.setComdat(TheModule.getOrInsertComdat(GO.getName()));
5179 }
5180 
5181 /// Pass IsTentative as true if you want to create a tentative definition.
5182 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
5183                                             bool IsTentative) {
5184   // OpenCL global variables of sampler type are translated to function calls,
5185   // therefore no need to be translated.
5186   QualType ASTTy = D->getType();
5187   if (getLangOpts().OpenCL && ASTTy->isSamplerT())
5188     return;
5189 
5190   // If this is OpenMP device, check if it is legal to emit this global
5191   // normally.
5192   if (LangOpts.OpenMPIsTargetDevice && OpenMPRuntime &&
5193       OpenMPRuntime->emitTargetGlobalVariable(D))
5194     return;
5195 
5196   llvm::TrackingVH<llvm::Constant> Init;
5197   bool NeedsGlobalCtor = false;
5198   // Whether the definition of the variable is available externally.
5199   // If yes, we shouldn't emit the GloablCtor and GlobalDtor for the variable
5200   // since this is the job for its original source.
5201   bool IsDefinitionAvailableExternally =
5202       getContext().GetGVALinkageForVariable(D) == GVA_AvailableExternally;
5203   bool NeedsGlobalDtor =
5204       !IsDefinitionAvailableExternally &&
5205       D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
5206 
5207   const VarDecl *InitDecl;
5208   const Expr *InitExpr = D->getAnyInitializer(InitDecl);
5209 
5210   std::optional<ConstantEmitter> emitter;
5211 
5212   // CUDA E.2.4.1 "__shared__ variables cannot have an initialization
5213   // as part of their declaration."  Sema has already checked for
5214   // error cases, so we just need to set Init to UndefValue.
5215   bool IsCUDASharedVar =
5216       getLangOpts().CUDAIsDevice && D->hasAttr<CUDASharedAttr>();
5217   // Shadows of initialized device-side global variables are also left
5218   // undefined.
5219   // Managed Variables should be initialized on both host side and device side.
5220   bool IsCUDAShadowVar =
5221       !getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
5222       (D->hasAttr<CUDAConstantAttr>() || D->hasAttr<CUDADeviceAttr>() ||
5223        D->hasAttr<CUDASharedAttr>());
5224   bool IsCUDADeviceShadowVar =
5225       getLangOpts().CUDAIsDevice && !D->hasAttr<HIPManagedAttr>() &&
5226       (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
5227        D->getType()->isCUDADeviceBuiltinTextureType());
5228   if (getLangOpts().CUDA &&
5229       (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
5230     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
5231   else if (D->hasAttr<LoaderUninitializedAttr>())
5232     Init = llvm::UndefValue::get(getTypes().ConvertTypeForMem(ASTTy));
5233   else if (!InitExpr) {
5234     // This is a tentative definition; tentative definitions are
5235     // implicitly initialized with { 0 }.
5236     //
5237     // Note that tentative definitions are only emitted at the end of
5238     // a translation unit, so they should never have incomplete
5239     // type. In addition, EmitTentativeDefinition makes sure that we
5240     // never attempt to emit a tentative definition if a real one
5241     // exists. A use may still exists, however, so we still may need
5242     // to do a RAUW.
5243     assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
5244     Init = EmitNullConstant(D->getType());
5245   } else {
5246     initializedGlobalDecl = GlobalDecl(D);
5247     emitter.emplace(*this);
5248     llvm::Constant *Initializer = emitter->tryEmitForInitializer(*InitDecl);
5249     if (!Initializer) {
5250       QualType T = InitExpr->getType();
5251       if (D->getType()->isReferenceType())
5252         T = D->getType();
5253 
5254       if (getLangOpts().CPlusPlus) {
5255         if (InitDecl->hasFlexibleArrayInit(getContext()))
5256           ErrorUnsupported(D, "flexible array initializer");
5257         Init = EmitNullConstant(T);
5258 
5259         if (!IsDefinitionAvailableExternally)
5260           NeedsGlobalCtor = true;
5261       } else {
5262         ErrorUnsupported(D, "static initializer");
5263         Init = llvm::UndefValue::get(getTypes().ConvertType(T));
5264       }
5265     } else {
5266       Init = Initializer;
5267       // We don't need an initializer, so remove the entry for the delayed
5268       // initializer position (just in case this entry was delayed) if we
5269       // also don't need to register a destructor.
5270       if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
5271         DelayedCXXInitPosition.erase(D);
5272 
5273 #ifndef NDEBUG
5274       CharUnits VarSize = getContext().getTypeSizeInChars(ASTTy) +
5275                           InitDecl->getFlexibleArrayInitChars(getContext());
5276       CharUnits CstSize = CharUnits::fromQuantity(
5277           getDataLayout().getTypeAllocSize(Init->getType()));
5278       assert(VarSize == CstSize && "Emitted constant has unexpected size");
5279 #endif
5280     }
5281   }
5282 
5283   llvm::Type* InitType = Init->getType();
5284   llvm::Constant *Entry =
5285       GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative));
5286 
5287   // Strip off pointer casts if we got them.
5288   Entry = Entry->stripPointerCasts();
5289 
5290   // Entry is now either a Function or GlobalVariable.
5291   auto *GV = dyn_cast<llvm::GlobalVariable>(Entry);
5292 
5293   // We have a definition after a declaration with the wrong type.
5294   // We must make a new GlobalVariable* and update everything that used OldGV
5295   // (a declaration or tentative definition) with the new GlobalVariable*
5296   // (which will be a definition).
5297   //
5298   // This happens if there is a prototype for a global (e.g.
5299   // "extern int x[];") and then a definition of a different type (e.g.
5300   // "int x[10];"). This also happens when an initializer has a different type
5301   // from the type of the global (this happens with unions).
5302   if (!GV || GV->getValueType() != InitType ||
5303       GV->getType()->getAddressSpace() !=
5304           getContext().getTargetAddressSpace(GetGlobalVarAddressSpace(D))) {
5305 
5306     // Move the old entry aside so that we'll create a new one.
5307     Entry->setName(StringRef());
5308 
5309     // Make a new global with the correct type, this is now guaranteed to work.
5310     GV = cast<llvm::GlobalVariable>(
5311         GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative))
5312             ->stripPointerCasts());
5313 
5314     // Replace all uses of the old global with the new global
5315     llvm::Constant *NewPtrForOldDecl =
5316         llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV,
5317                                                              Entry->getType());
5318     Entry->replaceAllUsesWith(NewPtrForOldDecl);
5319 
5320     // Erase the old global, since it is no longer used.
5321     cast<llvm::GlobalValue>(Entry)->eraseFromParent();
5322   }
5323 
5324   MaybeHandleStaticInExternC(D, GV);
5325 
5326   if (D->hasAttr<AnnotateAttr>())
5327     AddGlobalAnnotations(D, GV);
5328 
5329   // Set the llvm linkage type as appropriate.
5330   llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(D);
5331 
5332   // CUDA B.2.1 "The __device__ qualifier declares a variable that resides on
5333   // the device. [...]"
5334   // CUDA B.2.2 "The __constant__ qualifier, optionally used together with
5335   // __device__, declares a variable that: [...]
5336   // Is accessible from all the threads within the grid and from the host
5337   // through the runtime library (cudaGetSymbolAddress() / cudaGetSymbolSize()
5338   // / cudaMemcpyToSymbol() / cudaMemcpyFromSymbol())."
5339   if (LangOpts.CUDA) {
5340     if (LangOpts.CUDAIsDevice) {
5341       if (Linkage != llvm::GlobalValue::InternalLinkage &&
5342           (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>() ||
5343            D->getType()->isCUDADeviceBuiltinSurfaceType() ||
5344            D->getType()->isCUDADeviceBuiltinTextureType()))
5345         GV->setExternallyInitialized(true);
5346     } else {
5347       getCUDARuntime().internalizeDeviceSideVar(D, Linkage);
5348     }
5349     getCUDARuntime().handleVarRegistration(D, *GV);
5350   }
5351 
5352   GV->setInitializer(Init);
5353   if (emitter)
5354     emitter->finalize(GV);
5355 
5356   // If it is safe to mark the global 'constant', do so now.
5357   GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor &&
5358                   D->getType().isConstantStorage(getContext(), true, true));
5359 
5360   // If it is in a read-only section, mark it 'constant'.
5361   if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
5362     const ASTContext::SectionInfo &SI = Context.SectionInfos[SA->getName()];
5363     if ((SI.SectionFlags & ASTContext::PSF_Write) == 0)
5364       GV->setConstant(true);
5365   }
5366 
5367   CharUnits AlignVal = getContext().getDeclAlign(D);
5368   // Check for alignment specifed in an 'omp allocate' directive.
5369   if (std::optional<CharUnits> AlignValFromAllocate =
5370           getOMPAllocateAlignment(D))
5371     AlignVal = *AlignValFromAllocate;
5372   GV->setAlignment(AlignVal.getAsAlign());
5373 
5374   // On Darwin, unlike other Itanium C++ ABI platforms, the thread-wrapper
5375   // function is only defined alongside the variable, not also alongside
5376   // callers. Normally, all accesses to a thread_local go through the
5377   // thread-wrapper in order to ensure initialization has occurred, underlying
5378   // variable will never be used other than the thread-wrapper, so it can be
5379   // converted to internal linkage.
5380   //
5381   // However, if the variable has the 'constinit' attribute, it _can_ be
5382   // referenced directly, without calling the thread-wrapper, so the linkage
5383   // must not be changed.
5384   //
5385   // Additionally, if the variable isn't plain external linkage, e.g. if it's
5386   // weak or linkonce, the de-duplication semantics are important to preserve,
5387   // so we don't change the linkage.
5388   if (D->getTLSKind() == VarDecl::TLS_Dynamic &&
5389       Linkage == llvm::GlobalValue::ExternalLinkage &&
5390       Context.getTargetInfo().getTriple().isOSDarwin() &&
5391       !D->hasAttr<ConstInitAttr>())
5392     Linkage = llvm::GlobalValue::InternalLinkage;
5393 
5394   GV->setLinkage(Linkage);
5395   if (D->hasAttr<DLLImportAttr>())
5396     GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
5397   else if (D->hasAttr<DLLExportAttr>())
5398     GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
5399   else
5400     GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
5401 
5402   if (Linkage == llvm::GlobalVariable::CommonLinkage) {
5403     // common vars aren't constant even if declared const.
5404     GV->setConstant(false);
5405     // Tentative definition of global variables may be initialized with
5406     // non-zero null pointers. In this case they should have weak linkage
5407     // since common linkage must have zero initializer and must not have
5408     // explicit section therefore cannot have non-zero initial value.
5409     if (!GV->getInitializer()->isNullValue())
5410       GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
5411   }
5412 
5413   setNonAliasAttributes(D, GV);
5414 
5415   if (D->getTLSKind() && !GV->isThreadLocal()) {
5416     if (D->getTLSKind() == VarDecl::TLS_Dynamic)
5417       CXXThreadLocals.push_back(D);
5418     setTLSMode(GV, *D);
5419   }
5420 
5421   maybeSetTrivialComdat(*D, *GV);
5422 
5423   // Emit the initializer function if necessary.
5424   if (NeedsGlobalCtor || NeedsGlobalDtor)
5425     EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
5426 
5427   SanitizerMD->reportGlobal(GV, *D, NeedsGlobalCtor);
5428 
5429   // Emit global variable debug information.
5430   if (CGDebugInfo *DI = getModuleDebugInfo())
5431     if (getCodeGenOpts().hasReducedDebugInfo())
5432       DI->EmitGlobalVariable(GV, D);
5433 }
5434 
5435 void CodeGenModule::EmitExternalVarDeclaration(const VarDecl *D) {
5436   if (CGDebugInfo *DI = getModuleDebugInfo())
5437     if (getCodeGenOpts().hasReducedDebugInfo()) {
5438       QualType ASTTy = D->getType();
5439       llvm::Type *Ty = getTypes().ConvertTypeForMem(D->getType());
5440       llvm::Constant *GV =
5441           GetOrCreateLLVMGlobal(D->getName(), Ty, ASTTy.getAddressSpace(), D);
5442       DI->EmitExternalVariable(
5443           cast<llvm::GlobalVariable>(GV->stripPointerCasts()), D);
5444     }
5445 }
5446 
5447 static bool isVarDeclStrongDefinition(const ASTContext &Context,
5448                                       CodeGenModule &CGM, const VarDecl *D,
5449                                       bool NoCommon) {
5450   // Don't give variables common linkage if -fno-common was specified unless it
5451   // was overridden by a NoCommon attribute.
5452   if ((NoCommon || D->hasAttr<NoCommonAttr>()) && !D->hasAttr<CommonAttr>())
5453     return true;
5454 
5455   // C11 6.9.2/2:
5456   //   A declaration of an identifier for an object that has file scope without
5457   //   an initializer, and without a storage-class specifier or with the
5458   //   storage-class specifier static, constitutes a tentative definition.
5459   if (D->getInit() || D->hasExternalStorage())
5460     return true;
5461 
5462   // A variable cannot be both common and exist in a section.
5463   if (D->hasAttr<SectionAttr>())
5464     return true;
5465 
5466   // A variable cannot be both common and exist in a section.
5467   // We don't try to determine which is the right section in the front-end.
5468   // If no specialized section name is applicable, it will resort to default.
5469   if (D->hasAttr<PragmaClangBSSSectionAttr>() ||
5470       D->hasAttr<PragmaClangDataSectionAttr>() ||
5471       D->hasAttr<PragmaClangRelroSectionAttr>() ||
5472       D->hasAttr<PragmaClangRodataSectionAttr>())
5473     return true;
5474 
5475   // Thread local vars aren't considered common linkage.
5476   if (D->getTLSKind())
5477     return true;
5478 
5479   // Tentative definitions marked with WeakImportAttr are true definitions.
5480   if (D->hasAttr<WeakImportAttr>())
5481     return true;
5482 
5483   // A variable cannot be both common and exist in a comdat.
5484   if (shouldBeInCOMDAT(CGM, *D))
5485     return true;
5486 
5487   // Declarations with a required alignment do not have common linkage in MSVC
5488   // mode.
5489   if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
5490     if (D->hasAttr<AlignedAttr>())
5491       return true;
5492     QualType VarType = D->getType();
5493     if (Context.isAlignmentRequired(VarType))
5494       return true;
5495 
5496     if (const auto *RT = VarType->getAs<RecordType>()) {
5497       const RecordDecl *RD = RT->getDecl();
5498       for (const FieldDecl *FD : RD->fields()) {
5499         if (FD->isBitField())
5500           continue;
5501         if (FD->hasAttr<AlignedAttr>())
5502           return true;
5503         if (Context.isAlignmentRequired(FD->getType()))
5504           return true;
5505       }
5506     }
5507   }
5508 
5509   // Microsoft's link.exe doesn't support alignments greater than 32 bytes for
5510   // common symbols, so symbols with greater alignment requirements cannot be
5511   // common.
5512   // Other COFF linkers (ld.bfd and LLD) support arbitrary power-of-two
5513   // alignments for common symbols via the aligncomm directive, so this
5514   // restriction only applies to MSVC environments.
5515   if (Context.getTargetInfo().getTriple().isKnownWindowsMSVCEnvironment() &&
5516       Context.getTypeAlignIfKnown(D->getType()) >
5517           Context.toBits(CharUnits::fromQuantity(32)))
5518     return true;
5519 
5520   return false;
5521 }
5522 
5523 llvm::GlobalValue::LinkageTypes
5524 CodeGenModule::getLLVMLinkageForDeclarator(const DeclaratorDecl *D,
5525                                            GVALinkage Linkage) {
5526   if (Linkage == GVA_Internal)
5527     return llvm::Function::InternalLinkage;
5528 
5529   if (D->hasAttr<WeakAttr>())
5530     return llvm::GlobalVariable::WeakAnyLinkage;
5531 
5532   if (const auto *FD = D->getAsFunction())
5533     if (FD->isMultiVersion() && Linkage == GVA_AvailableExternally)
5534       return llvm::GlobalVariable::LinkOnceAnyLinkage;
5535 
5536   // We are guaranteed to have a strong definition somewhere else,
5537   // so we can use available_externally linkage.
5538   if (Linkage == GVA_AvailableExternally)
5539     return llvm::GlobalValue::AvailableExternallyLinkage;
5540 
5541   // Note that Apple's kernel linker doesn't support symbol
5542   // coalescing, so we need to avoid linkonce and weak linkages there.
5543   // Normally, this means we just map to internal, but for explicit
5544   // instantiations we'll map to external.
5545 
5546   // In C++, the compiler has to emit a definition in every translation unit
5547   // that references the function.  We should use linkonce_odr because
5548   // a) if all references in this translation unit are optimized away, we
5549   // don't need to codegen it.  b) if the function persists, it needs to be
5550   // merged with other definitions. c) C++ has the ODR, so we know the
5551   // definition is dependable.
5552   if (Linkage == GVA_DiscardableODR)
5553     return !Context.getLangOpts().AppleKext ? llvm::Function::LinkOnceODRLinkage
5554                                             : llvm::Function::InternalLinkage;
5555 
5556   // An explicit instantiation of a template has weak linkage, since
5557   // explicit instantiations can occur in multiple translation units
5558   // and must all be equivalent. However, we are not allowed to
5559   // throw away these explicit instantiations.
5560   //
5561   // CUDA/HIP: For -fno-gpu-rdc case, device code is limited to one TU,
5562   // so say that CUDA templates are either external (for kernels) or internal.
5563   // This lets llvm perform aggressive inter-procedural optimizations. For
5564   // -fgpu-rdc case, device function calls across multiple TU's are allowed,
5565   // therefore we need to follow the normal linkage paradigm.
5566   if (Linkage == GVA_StrongODR) {
5567     if (getLangOpts().AppleKext)
5568       return llvm::Function::ExternalLinkage;
5569     if (getLangOpts().CUDA && getLangOpts().CUDAIsDevice &&
5570         !getLangOpts().GPURelocatableDeviceCode)
5571       return D->hasAttr<CUDAGlobalAttr>() ? llvm::Function::ExternalLinkage
5572                                           : llvm::Function::InternalLinkage;
5573     return llvm::Function::WeakODRLinkage;
5574   }
5575 
5576   // C++ doesn't have tentative definitions and thus cannot have common
5577   // linkage.
5578   if (!getLangOpts().CPlusPlus && isa<VarDecl>(D) &&
5579       !isVarDeclStrongDefinition(Context, *this, cast<VarDecl>(D),
5580                                  CodeGenOpts.NoCommon))
5581     return llvm::GlobalVariable::CommonLinkage;
5582 
5583   // selectany symbols are externally visible, so use weak instead of
5584   // linkonce.  MSVC optimizes away references to const selectany globals, so
5585   // all definitions should be the same and ODR linkage should be used.
5586   // http://msdn.microsoft.com/en-us/library/5tkz6s71.aspx
5587   if (D->hasAttr<SelectAnyAttr>())
5588     return llvm::GlobalVariable::WeakODRLinkage;
5589 
5590   // Otherwise, we have strong external linkage.
5591   assert(Linkage == GVA_StrongExternal);
5592   return llvm::GlobalVariable::ExternalLinkage;
5593 }
5594 
5595 llvm::GlobalValue::LinkageTypes
5596 CodeGenModule::getLLVMLinkageVarDefinition(const VarDecl *VD) {
5597   GVALinkage Linkage = getContext().GetGVALinkageForVariable(VD);
5598   return getLLVMLinkageForDeclarator(VD, Linkage);
5599 }
5600 
5601 /// Replace the uses of a function that was declared with a non-proto type.
5602 /// We want to silently drop extra arguments from call sites
5603 static void replaceUsesOfNonProtoConstant(llvm::Constant *old,
5604                                           llvm::Function *newFn) {
5605   // Fast path.
5606   if (old->use_empty()) return;
5607 
5608   llvm::Type *newRetTy = newFn->getReturnType();
5609   SmallVector<llvm::Value*, 4> newArgs;
5610 
5611   for (llvm::Value::use_iterator ui = old->use_begin(), ue = old->use_end();
5612          ui != ue; ) {
5613     llvm::Value::use_iterator use = ui++; // Increment before the use is erased.
5614     llvm::User *user = use->getUser();
5615 
5616     // Recognize and replace uses of bitcasts.  Most calls to
5617     // unprototyped functions will use bitcasts.
5618     if (auto *bitcast = dyn_cast<llvm::ConstantExpr>(user)) {
5619       if (bitcast->getOpcode() == llvm::Instruction::BitCast)
5620         replaceUsesOfNonProtoConstant(bitcast, newFn);
5621       continue;
5622     }
5623 
5624     // Recognize calls to the function.
5625     llvm::CallBase *callSite = dyn_cast<llvm::CallBase>(user);
5626     if (!callSite) continue;
5627     if (!callSite->isCallee(&*use))
5628       continue;
5629 
5630     // If the return types don't match exactly, then we can't
5631     // transform this call unless it's dead.
5632     if (callSite->getType() != newRetTy && !callSite->use_empty())
5633       continue;
5634 
5635     // Get the call site's attribute list.
5636     SmallVector<llvm::AttributeSet, 8> newArgAttrs;
5637     llvm::AttributeList oldAttrs = callSite->getAttributes();
5638 
5639     // If the function was passed too few arguments, don't transform.
5640     unsigned newNumArgs = newFn->arg_size();
5641     if (callSite->arg_size() < newNumArgs)
5642       continue;
5643 
5644     // If extra arguments were passed, we silently drop them.
5645     // If any of the types mismatch, we don't transform.
5646     unsigned argNo = 0;
5647     bool dontTransform = false;
5648     for (llvm::Argument &A : newFn->args()) {
5649       if (callSite->getArgOperand(argNo)->getType() != A.getType()) {
5650         dontTransform = true;
5651         break;
5652       }
5653 
5654       // Add any parameter attributes.
5655       newArgAttrs.push_back(oldAttrs.getParamAttrs(argNo));
5656       argNo++;
5657     }
5658     if (dontTransform)
5659       continue;
5660 
5661     // Okay, we can transform this.  Create the new call instruction and copy
5662     // over the required information.
5663     newArgs.append(callSite->arg_begin(), callSite->arg_begin() + argNo);
5664 
5665     // Copy over any operand bundles.
5666     SmallVector<llvm::OperandBundleDef, 1> newBundles;
5667     callSite->getOperandBundlesAsDefs(newBundles);
5668 
5669     llvm::CallBase *newCall;
5670     if (isa<llvm::CallInst>(callSite)) {
5671       newCall =
5672           llvm::CallInst::Create(newFn, newArgs, newBundles, "", callSite);
5673     } else {
5674       auto *oldInvoke = cast<llvm::InvokeInst>(callSite);
5675       newCall = llvm::InvokeInst::Create(newFn, oldInvoke->getNormalDest(),
5676                                          oldInvoke->getUnwindDest(), newArgs,
5677                                          newBundles, "", callSite);
5678     }
5679     newArgs.clear(); // for the next iteration
5680 
5681     if (!newCall->getType()->isVoidTy())
5682       newCall->takeName(callSite);
5683     newCall->setAttributes(
5684         llvm::AttributeList::get(newFn->getContext(), oldAttrs.getFnAttrs(),
5685                                  oldAttrs.getRetAttrs(), newArgAttrs));
5686     newCall->setCallingConv(callSite->getCallingConv());
5687 
5688     // Finally, remove the old call, replacing any uses with the new one.
5689     if (!callSite->use_empty())
5690       callSite->replaceAllUsesWith(newCall);
5691 
5692     // Copy debug location attached to CI.
5693     if (callSite->getDebugLoc())
5694       newCall->setDebugLoc(callSite->getDebugLoc());
5695 
5696     callSite->eraseFromParent();
5697   }
5698 }
5699 
5700 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
5701 /// implement a function with no prototype, e.g. "int foo() {}".  If there are
5702 /// existing call uses of the old function in the module, this adjusts them to
5703 /// call the new function directly.
5704 ///
5705 /// This is not just a cleanup: the always_inline pass requires direct calls to
5706 /// functions to be able to inline them.  If there is a bitcast in the way, it
5707 /// won't inline them.  Instcombine normally deletes these calls, but it isn't
5708 /// run at -O0.
5709 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
5710                                                       llvm::Function *NewFn) {
5711   // If we're redefining a global as a function, don't transform it.
5712   if (!isa<llvm::Function>(Old)) return;
5713 
5714   replaceUsesOfNonProtoConstant(Old, NewFn);
5715 }
5716 
5717 void CodeGenModule::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
5718   auto DK = VD->isThisDeclarationADefinition();
5719   if (DK == VarDecl::Definition && VD->hasAttr<DLLImportAttr>())
5720     return;
5721 
5722   TemplateSpecializationKind TSK = VD->getTemplateSpecializationKind();
5723   // If we have a definition, this might be a deferred decl. If the
5724   // instantiation is explicit, make sure we emit it at the end.
5725   if (VD->getDefinition() && TSK == TSK_ExplicitInstantiationDefinition)
5726     GetAddrOfGlobalVar(VD);
5727 
5728   EmitTopLevelDecl(VD);
5729 }
5730 
5731 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
5732                                                  llvm::GlobalValue *GV) {
5733   const auto *D = cast<FunctionDecl>(GD.getDecl());
5734 
5735   // Compute the function info and LLVM type.
5736   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
5737   llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
5738 
5739   // Get or create the prototype for the function.
5740   if (!GV || (GV->getValueType() != Ty))
5741     GV = cast<llvm::GlobalValue>(GetAddrOfFunction(GD, Ty, /*ForVTable=*/false,
5742                                                    /*DontDefer=*/true,
5743                                                    ForDefinition));
5744 
5745   // Already emitted.
5746   if (!GV->isDeclaration())
5747     return;
5748 
5749   // We need to set linkage and visibility on the function before
5750   // generating code for it because various parts of IR generation
5751   // want to propagate this information down (e.g. to local static
5752   // declarations).
5753   auto *Fn = cast<llvm::Function>(GV);
5754   setFunctionLinkage(GD, Fn);
5755 
5756   // FIXME: this is redundant with part of setFunctionDefinitionAttributes
5757   setGVProperties(Fn, GD);
5758 
5759   MaybeHandleStaticInExternC(D, Fn);
5760 
5761   maybeSetTrivialComdat(*D, *Fn);
5762 
5763   CodeGenFunction(*this).GenerateCode(GD, Fn, FI);
5764 
5765   setNonAliasAttributes(GD, Fn);
5766   SetLLVMFunctionAttributesForDefinition(D, Fn);
5767 
5768   if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
5769     AddGlobalCtor(Fn, CA->getPriority());
5770   if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
5771     AddGlobalDtor(Fn, DA->getPriority(), true);
5772   if (getLangOpts().OpenMP && D->hasAttr<OMPDeclareTargetDeclAttr>())
5773     getOpenMPRuntime().emitDeclareTargetFunction(D, GV);
5774 }
5775 
5776 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
5777   const auto *D = cast<ValueDecl>(GD.getDecl());
5778   const AliasAttr *AA = D->getAttr<AliasAttr>();
5779   assert(AA && "Not an alias?");
5780 
5781   StringRef MangledName = getMangledName(GD);
5782 
5783   if (AA->getAliasee() == MangledName) {
5784     Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
5785     return;
5786   }
5787 
5788   // If there is a definition in the module, then it wins over the alias.
5789   // This is dubious, but allow it to be safe.  Just ignore the alias.
5790   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
5791   if (Entry && !Entry->isDeclaration())
5792     return;
5793 
5794   Aliases.push_back(GD);
5795 
5796   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
5797 
5798   // Create a reference to the named value.  This ensures that it is emitted
5799   // if a deferred decl.
5800   llvm::Constant *Aliasee;
5801   llvm::GlobalValue::LinkageTypes LT;
5802   if (isa<llvm::FunctionType>(DeclTy)) {
5803     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GD,
5804                                       /*ForVTable=*/false);
5805     LT = getFunctionLinkage(GD);
5806   } else {
5807     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(), DeclTy, LangAS::Default,
5808                                     /*D=*/nullptr);
5809     if (const auto *VD = dyn_cast<VarDecl>(GD.getDecl()))
5810       LT = getLLVMLinkageVarDefinition(VD);
5811     else
5812       LT = getFunctionLinkage(GD);
5813   }
5814 
5815   // Create the new alias itself, but don't set a name yet.
5816   unsigned AS = Aliasee->getType()->getPointerAddressSpace();
5817   auto *GA =
5818       llvm::GlobalAlias::create(DeclTy, AS, LT, "", Aliasee, &getModule());
5819 
5820   if (Entry) {
5821     if (GA->getAliasee() == Entry) {
5822       Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
5823       return;
5824     }
5825 
5826     assert(Entry->isDeclaration());
5827 
5828     // If there is a declaration in the module, then we had an extern followed
5829     // by the alias, as in:
5830     //   extern int test6();
5831     //   ...
5832     //   int test6() __attribute__((alias("test7")));
5833     //
5834     // Remove it and replace uses of it with the alias.
5835     GA->takeName(Entry);
5836 
5837     Entry->replaceAllUsesWith(GA);
5838     Entry->eraseFromParent();
5839   } else {
5840     GA->setName(MangledName);
5841   }
5842 
5843   // Set attributes which are particular to an alias; this is a
5844   // specialization of the attributes which may be set on a global
5845   // variable/function.
5846   if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakRefAttr>() ||
5847       D->isWeakImported()) {
5848     GA->setLinkage(llvm::Function::WeakAnyLinkage);
5849   }
5850 
5851   if (const auto *VD = dyn_cast<VarDecl>(D))
5852     if (VD->getTLSKind())
5853       setTLSMode(GA, *VD);
5854 
5855   SetCommonAttributes(GD, GA);
5856 
5857   // Emit global alias debug information.
5858   if (isa<VarDecl>(D))
5859     if (CGDebugInfo *DI = getModuleDebugInfo())
5860       DI->EmitGlobalAlias(cast<llvm::GlobalValue>(GA->getAliasee()->stripPointerCasts()), GD);
5861 }
5862 
5863 void CodeGenModule::emitIFuncDefinition(GlobalDecl GD) {
5864   const auto *D = cast<ValueDecl>(GD.getDecl());
5865   const IFuncAttr *IFA = D->getAttr<IFuncAttr>();
5866   assert(IFA && "Not an ifunc?");
5867 
5868   StringRef MangledName = getMangledName(GD);
5869 
5870   if (IFA->getResolver() == MangledName) {
5871     Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
5872     return;
5873   }
5874 
5875   // Report an error if some definition overrides ifunc.
5876   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
5877   if (Entry && !Entry->isDeclaration()) {
5878     GlobalDecl OtherGD;
5879     if (lookupRepresentativeDecl(MangledName, OtherGD) &&
5880         DiagnosedConflictingDefinitions.insert(GD).second) {
5881       Diags.Report(D->getLocation(), diag::err_duplicate_mangled_name)
5882           << MangledName;
5883       Diags.Report(OtherGD.getDecl()->getLocation(),
5884                    diag::note_previous_definition);
5885     }
5886     return;
5887   }
5888 
5889   Aliases.push_back(GD);
5890 
5891   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
5892   llvm::Type *ResolverTy = llvm::GlobalIFunc::getResolverFunctionType(DeclTy);
5893   llvm::Constant *Resolver =
5894       GetOrCreateLLVMFunction(IFA->getResolver(), ResolverTy, {},
5895                               /*ForVTable=*/false);
5896   llvm::GlobalIFunc *GIF =
5897       llvm::GlobalIFunc::create(DeclTy, 0, llvm::Function::ExternalLinkage,
5898                                 "", Resolver, &getModule());
5899   if (Entry) {
5900     if (GIF->getResolver() == Entry) {
5901       Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
5902       return;
5903     }
5904     assert(Entry->isDeclaration());
5905 
5906     // If there is a declaration in the module, then we had an extern followed
5907     // by the ifunc, as in:
5908     //   extern int test();
5909     //   ...
5910     //   int test() __attribute__((ifunc("resolver")));
5911     //
5912     // Remove it and replace uses of it with the ifunc.
5913     GIF->takeName(Entry);
5914 
5915     Entry->replaceAllUsesWith(GIF);
5916     Entry->eraseFromParent();
5917   } else
5918     GIF->setName(MangledName);
5919   if (auto *F = dyn_cast<llvm::Function>(Resolver)) {
5920     F->addFnAttr(llvm::Attribute::DisableSanitizerInstrumentation);
5921   }
5922   SetCommonAttributes(GD, GIF);
5923 }
5924 
5925 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,
5926                                             ArrayRef<llvm::Type*> Tys) {
5927   return llvm::Intrinsic::getDeclaration(&getModule(), (llvm::Intrinsic::ID)IID,
5928                                          Tys);
5929 }
5930 
5931 static llvm::StringMapEntry<llvm::GlobalVariable *> &
5932 GetConstantCFStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
5933                          const StringLiteral *Literal, bool TargetIsLSB,
5934                          bool &IsUTF16, unsigned &StringLength) {
5935   StringRef String = Literal->getString();
5936   unsigned NumBytes = String.size();
5937 
5938   // Check for simple case.
5939   if (!Literal->containsNonAsciiOrNull()) {
5940     StringLength = NumBytes;
5941     return *Map.insert(std::make_pair(String, nullptr)).first;
5942   }
5943 
5944   // Otherwise, convert the UTF8 literals into a string of shorts.
5945   IsUTF16 = true;
5946 
5947   SmallVector<llvm::UTF16, 128> ToBuf(NumBytes + 1); // +1 for ending nulls.
5948   const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)String.data();
5949   llvm::UTF16 *ToPtr = &ToBuf[0];
5950 
5951   (void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, &ToPtr,
5952                                  ToPtr + NumBytes, llvm::strictConversion);
5953 
5954   // ConvertUTF8toUTF16 returns the length in ToPtr.
5955   StringLength = ToPtr - &ToBuf[0];
5956 
5957   // Add an explicit null.
5958   *ToPtr = 0;
5959   return *Map.insert(std::make_pair(
5960                          StringRef(reinterpret_cast<const char *>(ToBuf.data()),
5961                                    (StringLength + 1) * 2),
5962                          nullptr)).first;
5963 }
5964 
5965 ConstantAddress
5966 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
5967   unsigned StringLength = 0;
5968   bool isUTF16 = false;
5969   llvm::StringMapEntry<llvm::GlobalVariable *> &Entry =
5970       GetConstantCFStringEntry(CFConstantStringMap, Literal,
5971                                getDataLayout().isLittleEndian(), isUTF16,
5972                                StringLength);
5973 
5974   if (auto *C = Entry.second)
5975     return ConstantAddress(
5976         C, C->getValueType(), CharUnits::fromQuantity(C->getAlignment()));
5977 
5978   llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty);
5979   llvm::Constant *Zeros[] = { Zero, Zero };
5980 
5981   const ASTContext &Context = getContext();
5982   const llvm::Triple &Triple = getTriple();
5983 
5984   const auto CFRuntime = getLangOpts().CFRuntime;
5985   const bool IsSwiftABI =
5986       static_cast<unsigned>(CFRuntime) >=
5987       static_cast<unsigned>(LangOptions::CoreFoundationABI::Swift);
5988   const bool IsSwift4_1 = CFRuntime == LangOptions::CoreFoundationABI::Swift4_1;
5989 
5990   // If we don't already have it, get __CFConstantStringClassReference.
5991   if (!CFConstantStringClassRef) {
5992     const char *CFConstantStringClassName = "__CFConstantStringClassReference";
5993     llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
5994     Ty = llvm::ArrayType::get(Ty, 0);
5995 
5996     switch (CFRuntime) {
5997     default: break;
5998     case LangOptions::CoreFoundationABI::Swift: [[fallthrough]];
5999     case LangOptions::CoreFoundationABI::Swift5_0:
6000       CFConstantStringClassName =
6001           Triple.isOSDarwin() ? "$s15SwiftFoundation19_NSCFConstantStringCN"
6002                               : "$s10Foundation19_NSCFConstantStringCN";
6003       Ty = IntPtrTy;
6004       break;
6005     case LangOptions::CoreFoundationABI::Swift4_2:
6006       CFConstantStringClassName =
6007           Triple.isOSDarwin() ? "$S15SwiftFoundation19_NSCFConstantStringCN"
6008                               : "$S10Foundation19_NSCFConstantStringCN";
6009       Ty = IntPtrTy;
6010       break;
6011     case LangOptions::CoreFoundationABI::Swift4_1:
6012       CFConstantStringClassName =
6013           Triple.isOSDarwin() ? "__T015SwiftFoundation19_NSCFConstantStringCN"
6014                               : "__T010Foundation19_NSCFConstantStringCN";
6015       Ty = IntPtrTy;
6016       break;
6017     }
6018 
6019     llvm::Constant *C = CreateRuntimeVariable(Ty, CFConstantStringClassName);
6020 
6021     if (Triple.isOSBinFormatELF() || Triple.isOSBinFormatCOFF()) {
6022       llvm::GlobalValue *GV = nullptr;
6023 
6024       if ((GV = dyn_cast<llvm::GlobalValue>(C))) {
6025         IdentifierInfo &II = Context.Idents.get(GV->getName());
6026         TranslationUnitDecl *TUDecl = Context.getTranslationUnitDecl();
6027         DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
6028 
6029         const VarDecl *VD = nullptr;
6030         for (const auto *Result : DC->lookup(&II))
6031           if ((VD = dyn_cast<VarDecl>(Result)))
6032             break;
6033 
6034         if (Triple.isOSBinFormatELF()) {
6035           if (!VD)
6036             GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
6037         } else {
6038           GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
6039           if (!VD || !VD->hasAttr<DLLExportAttr>())
6040             GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
6041           else
6042             GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
6043         }
6044 
6045         setDSOLocal(GV);
6046       }
6047     }
6048 
6049     // Decay array -> ptr
6050     CFConstantStringClassRef =
6051         IsSwiftABI ? llvm::ConstantExpr::getPtrToInt(C, Ty)
6052                    : llvm::ConstantExpr::getGetElementPtr(Ty, C, Zeros);
6053   }
6054 
6055   QualType CFTy = Context.getCFConstantStringType();
6056 
6057   auto *STy = cast<llvm::StructType>(getTypes().ConvertType(CFTy));
6058 
6059   ConstantInitBuilder Builder(*this);
6060   auto Fields = Builder.beginStruct(STy);
6061 
6062   // Class pointer.
6063   Fields.add(cast<llvm::Constant>(CFConstantStringClassRef));
6064 
6065   // Flags.
6066   if (IsSwiftABI) {
6067     Fields.addInt(IntPtrTy, IsSwift4_1 ? 0x05 : 0x01);
6068     Fields.addInt(Int64Ty, isUTF16 ? 0x07d0 : 0x07c8);
6069   } else {
6070     Fields.addInt(IntTy, isUTF16 ? 0x07d0 : 0x07C8);
6071   }
6072 
6073   // String pointer.
6074   llvm::Constant *C = nullptr;
6075   if (isUTF16) {
6076     auto Arr = llvm::ArrayRef(
6077         reinterpret_cast<uint16_t *>(const_cast<char *>(Entry.first().data())),
6078         Entry.first().size() / 2);
6079     C = llvm::ConstantDataArray::get(VMContext, Arr);
6080   } else {
6081     C = llvm::ConstantDataArray::getString(VMContext, Entry.first());
6082   }
6083 
6084   // Note: -fwritable-strings doesn't make the backing store strings of
6085   // CFStrings writable.
6086   auto *GV =
6087       new llvm::GlobalVariable(getModule(), C->getType(), /*isConstant=*/true,
6088                                llvm::GlobalValue::PrivateLinkage, C, ".str");
6089   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
6090   // Don't enforce the target's minimum global alignment, since the only use
6091   // of the string is via this class initializer.
6092   CharUnits Align = isUTF16 ? Context.getTypeAlignInChars(Context.ShortTy)
6093                             : Context.getTypeAlignInChars(Context.CharTy);
6094   GV->setAlignment(Align.getAsAlign());
6095 
6096   // FIXME: We set the section explicitly to avoid a bug in ld64 224.1.
6097   // Without it LLVM can merge the string with a non unnamed_addr one during
6098   // LTO.  Doing that changes the section it ends in, which surprises ld64.
6099   if (Triple.isOSBinFormatMachO())
6100     GV->setSection(isUTF16 ? "__TEXT,__ustring"
6101                            : "__TEXT,__cstring,cstring_literals");
6102   // Make sure the literal ends up in .rodata to allow for safe ICF and for
6103   // the static linker to adjust permissions to read-only later on.
6104   else if (Triple.isOSBinFormatELF())
6105     GV->setSection(".rodata");
6106 
6107   // String.
6108   llvm::Constant *Str =
6109       llvm::ConstantExpr::getGetElementPtr(GV->getValueType(), GV, Zeros);
6110 
6111   Fields.add(Str);
6112 
6113   // String length.
6114   llvm::IntegerType *LengthTy =
6115       llvm::IntegerType::get(getModule().getContext(),
6116                              Context.getTargetInfo().getLongWidth());
6117   if (IsSwiftABI) {
6118     if (CFRuntime == LangOptions::CoreFoundationABI::Swift4_1 ||
6119         CFRuntime == LangOptions::CoreFoundationABI::Swift4_2)
6120       LengthTy = Int32Ty;
6121     else
6122       LengthTy = IntPtrTy;
6123   }
6124   Fields.addInt(LengthTy, StringLength);
6125 
6126   // Swift ABI requires 8-byte alignment to ensure that the _Atomic(uint64_t) is
6127   // properly aligned on 32-bit platforms.
6128   CharUnits Alignment =
6129       IsSwiftABI ? Context.toCharUnitsFromBits(64) : getPointerAlign();
6130 
6131   // The struct.
6132   GV = Fields.finishAndCreateGlobal("_unnamed_cfstring_", Alignment,
6133                                     /*isConstant=*/false,
6134                                     llvm::GlobalVariable::PrivateLinkage);
6135   GV->addAttribute("objc_arc_inert");
6136   switch (Triple.getObjectFormat()) {
6137   case llvm::Triple::UnknownObjectFormat:
6138     llvm_unreachable("unknown file format");
6139   case llvm::Triple::DXContainer:
6140   case llvm::Triple::GOFF:
6141   case llvm::Triple::SPIRV:
6142   case llvm::Triple::XCOFF:
6143     llvm_unreachable("unimplemented");
6144   case llvm::Triple::COFF:
6145   case llvm::Triple::ELF:
6146   case llvm::Triple::Wasm:
6147     GV->setSection("cfstring");
6148     break;
6149   case llvm::Triple::MachO:
6150     GV->setSection("__DATA,__cfstring");
6151     break;
6152   }
6153   Entry.second = GV;
6154 
6155   return ConstantAddress(GV, GV->getValueType(), Alignment);
6156 }
6157 
6158 bool CodeGenModule::getExpressionLocationsEnabled() const {
6159   return !CodeGenOpts.EmitCodeView || CodeGenOpts.DebugColumnInfo;
6160 }
6161 
6162 QualType CodeGenModule::getObjCFastEnumerationStateType() {
6163   if (ObjCFastEnumerationStateType.isNull()) {
6164     RecordDecl *D = Context.buildImplicitRecord("__objcFastEnumerationState");
6165     D->startDefinition();
6166 
6167     QualType FieldTypes[] = {
6168         Context.UnsignedLongTy, Context.getPointerType(Context.getObjCIdType()),
6169         Context.getPointerType(Context.UnsignedLongTy),
6170         Context.getConstantArrayType(Context.UnsignedLongTy, llvm::APInt(32, 5),
6171                                      nullptr, ArraySizeModifier::Normal, 0)};
6172 
6173     for (size_t i = 0; i < 4; ++i) {
6174       FieldDecl *Field = FieldDecl::Create(Context,
6175                                            D,
6176                                            SourceLocation(),
6177                                            SourceLocation(), nullptr,
6178                                            FieldTypes[i], /*TInfo=*/nullptr,
6179                                            /*BitWidth=*/nullptr,
6180                                            /*Mutable=*/false,
6181                                            ICIS_NoInit);
6182       Field->setAccess(AS_public);
6183       D->addDecl(Field);
6184     }
6185 
6186     D->completeDefinition();
6187     ObjCFastEnumerationStateType = Context.getTagDeclType(D);
6188   }
6189 
6190   return ObjCFastEnumerationStateType;
6191 }
6192 
6193 llvm::Constant *
6194 CodeGenModule::GetConstantArrayFromStringLiteral(const StringLiteral *E) {
6195   assert(!E->getType()->isPointerType() && "Strings are always arrays");
6196 
6197   // Don't emit it as the address of the string, emit the string data itself
6198   // as an inline array.
6199   if (E->getCharByteWidth() == 1) {
6200     SmallString<64> Str(E->getString());
6201 
6202     // Resize the string to the right size, which is indicated by its type.
6203     const ConstantArrayType *CAT = Context.getAsConstantArrayType(E->getType());
6204     assert(CAT && "String literal not of constant array type!");
6205     Str.resize(CAT->getSize().getZExtValue());
6206     return llvm::ConstantDataArray::getString(VMContext, Str, false);
6207   }
6208 
6209   auto *AType = cast<llvm::ArrayType>(getTypes().ConvertType(E->getType()));
6210   llvm::Type *ElemTy = AType->getElementType();
6211   unsigned NumElements = AType->getNumElements();
6212 
6213   // Wide strings have either 2-byte or 4-byte elements.
6214   if (ElemTy->getPrimitiveSizeInBits() == 16) {
6215     SmallVector<uint16_t, 32> Elements;
6216     Elements.reserve(NumElements);
6217 
6218     for(unsigned i = 0, e = E->getLength(); i != e; ++i)
6219       Elements.push_back(E->getCodeUnit(i));
6220     Elements.resize(NumElements);
6221     return llvm::ConstantDataArray::get(VMContext, Elements);
6222   }
6223 
6224   assert(ElemTy->getPrimitiveSizeInBits() == 32);
6225   SmallVector<uint32_t, 32> Elements;
6226   Elements.reserve(NumElements);
6227 
6228   for(unsigned i = 0, e = E->getLength(); i != e; ++i)
6229     Elements.push_back(E->getCodeUnit(i));
6230   Elements.resize(NumElements);
6231   return llvm::ConstantDataArray::get(VMContext, Elements);
6232 }
6233 
6234 static llvm::GlobalVariable *
6235 GenerateStringLiteral(llvm::Constant *C, llvm::GlobalValue::LinkageTypes LT,
6236                       CodeGenModule &CGM, StringRef GlobalName,
6237                       CharUnits Alignment) {
6238   unsigned AddrSpace = CGM.getContext().getTargetAddressSpace(
6239       CGM.GetGlobalConstantAddressSpace());
6240 
6241   llvm::Module &M = CGM.getModule();
6242   // Create a global variable for this string
6243   auto *GV = new llvm::GlobalVariable(
6244       M, C->getType(), !CGM.getLangOpts().WritableStrings, LT, C, GlobalName,
6245       nullptr, llvm::GlobalVariable::NotThreadLocal, AddrSpace);
6246   GV->setAlignment(Alignment.getAsAlign());
6247   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
6248   if (GV->isWeakForLinker()) {
6249     assert(CGM.supportsCOMDAT() && "Only COFF uses weak string literals");
6250     GV->setComdat(M.getOrInsertComdat(GV->getName()));
6251   }
6252   CGM.setDSOLocal(GV);
6253 
6254   return GV;
6255 }
6256 
6257 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a
6258 /// constant array for the given string literal.
6259 ConstantAddress
6260 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S,
6261                                                   StringRef Name) {
6262   CharUnits Alignment = getContext().getAlignOfGlobalVarInChars(S->getType());
6263 
6264   llvm::Constant *C = GetConstantArrayFromStringLiteral(S);
6265   llvm::GlobalVariable **Entry = nullptr;
6266   if (!LangOpts.WritableStrings) {
6267     Entry = &ConstantStringMap[C];
6268     if (auto GV = *Entry) {
6269       if (uint64_t(Alignment.getQuantity()) > GV->getAlignment())
6270         GV->setAlignment(Alignment.getAsAlign());
6271       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6272                              GV->getValueType(), Alignment);
6273     }
6274   }
6275 
6276   SmallString<256> MangledNameBuffer;
6277   StringRef GlobalVariableName;
6278   llvm::GlobalValue::LinkageTypes LT;
6279 
6280   // Mangle the string literal if that's how the ABI merges duplicate strings.
6281   // Don't do it if they are writable, since we don't want writes in one TU to
6282   // affect strings in another.
6283   if (getCXXABI().getMangleContext().shouldMangleStringLiteral(S) &&
6284       !LangOpts.WritableStrings) {
6285     llvm::raw_svector_ostream Out(MangledNameBuffer);
6286     getCXXABI().getMangleContext().mangleStringLiteral(S, Out);
6287     LT = llvm::GlobalValue::LinkOnceODRLinkage;
6288     GlobalVariableName = MangledNameBuffer;
6289   } else {
6290     LT = llvm::GlobalValue::PrivateLinkage;
6291     GlobalVariableName = Name;
6292   }
6293 
6294   auto GV = GenerateStringLiteral(C, LT, *this, GlobalVariableName, Alignment);
6295 
6296   CGDebugInfo *DI = getModuleDebugInfo();
6297   if (DI && getCodeGenOpts().hasReducedDebugInfo())
6298     DI->AddStringLiteralDebugInfo(GV, S);
6299 
6300   if (Entry)
6301     *Entry = GV;
6302 
6303   SanitizerMD->reportGlobal(GV, S->getStrTokenLoc(0), "<string literal>");
6304 
6305   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6306                          GV->getValueType(), Alignment);
6307 }
6308 
6309 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
6310 /// array for the given ObjCEncodeExpr node.
6311 ConstantAddress
6312 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
6313   std::string Str;
6314   getContext().getObjCEncodingForType(E->getEncodedType(), Str);
6315 
6316   return GetAddrOfConstantCString(Str);
6317 }
6318 
6319 /// GetAddrOfConstantCString - Returns a pointer to a character array containing
6320 /// the literal and a terminating '\0' character.
6321 /// The result has pointer to array type.
6322 ConstantAddress CodeGenModule::GetAddrOfConstantCString(
6323     const std::string &Str, const char *GlobalName) {
6324   StringRef StrWithNull(Str.c_str(), Str.size() + 1);
6325   CharUnits Alignment =
6326     getContext().getAlignOfGlobalVarInChars(getContext().CharTy);
6327 
6328   llvm::Constant *C =
6329       llvm::ConstantDataArray::getString(getLLVMContext(), StrWithNull, false);
6330 
6331   // Don't share any string literals if strings aren't constant.
6332   llvm::GlobalVariable **Entry = nullptr;
6333   if (!LangOpts.WritableStrings) {
6334     Entry = &ConstantStringMap[C];
6335     if (auto GV = *Entry) {
6336       if (uint64_t(Alignment.getQuantity()) > GV->getAlignment())
6337         GV->setAlignment(Alignment.getAsAlign());
6338       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6339                              GV->getValueType(), Alignment);
6340     }
6341   }
6342 
6343   // Get the default prefix if a name wasn't specified.
6344   if (!GlobalName)
6345     GlobalName = ".str";
6346   // Create a global variable for this.
6347   auto GV = GenerateStringLiteral(C, llvm::GlobalValue::PrivateLinkage, *this,
6348                                   GlobalName, Alignment);
6349   if (Entry)
6350     *Entry = GV;
6351 
6352   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
6353                          GV->getValueType(), Alignment);
6354 }
6355 
6356 ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(
6357     const MaterializeTemporaryExpr *E, const Expr *Init) {
6358   assert((E->getStorageDuration() == SD_Static ||
6359           E->getStorageDuration() == SD_Thread) && "not a global temporary");
6360   const auto *VD = cast<VarDecl>(E->getExtendingDecl());
6361 
6362   // If we're not materializing a subobject of the temporary, keep the
6363   // cv-qualifiers from the type of the MaterializeTemporaryExpr.
6364   QualType MaterializedType = Init->getType();
6365   if (Init == E->getSubExpr())
6366     MaterializedType = E->getType();
6367 
6368   CharUnits Align = getContext().getTypeAlignInChars(MaterializedType);
6369 
6370   auto InsertResult = MaterializedGlobalTemporaryMap.insert({E, nullptr});
6371   if (!InsertResult.second) {
6372     // We've seen this before: either we already created it or we're in the
6373     // process of doing so.
6374     if (!InsertResult.first->second) {
6375       // We recursively re-entered this function, probably during emission of
6376       // the initializer. Create a placeholder. We'll clean this up in the
6377       // outer call, at the end of this function.
6378       llvm::Type *Type = getTypes().ConvertTypeForMem(MaterializedType);
6379       InsertResult.first->second = new llvm::GlobalVariable(
6380           getModule(), Type, false, llvm::GlobalVariable::InternalLinkage,
6381           nullptr);
6382     }
6383     return ConstantAddress(InsertResult.first->second,
6384                            llvm::cast<llvm::GlobalVariable>(
6385                                InsertResult.first->second->stripPointerCasts())
6386                                ->getValueType(),
6387                            Align);
6388   }
6389 
6390   // FIXME: If an externally-visible declaration extends multiple temporaries,
6391   // we need to give each temporary the same name in every translation unit (and
6392   // we also need to make the temporaries externally-visible).
6393   SmallString<256> Name;
6394   llvm::raw_svector_ostream Out(Name);
6395   getCXXABI().getMangleContext().mangleReferenceTemporary(
6396       VD, E->getManglingNumber(), Out);
6397 
6398   APValue *Value = nullptr;
6399   if (E->getStorageDuration() == SD_Static && VD && VD->evaluateValue()) {
6400     // If the initializer of the extending declaration is a constant
6401     // initializer, we should have a cached constant initializer for this
6402     // temporary. Note that this might have a different value from the value
6403     // computed by evaluating the initializer if the surrounding constant
6404     // expression modifies the temporary.
6405     Value = E->getOrCreateValue(false);
6406   }
6407 
6408   // Try evaluating it now, it might have a constant initializer.
6409   Expr::EvalResult EvalResult;
6410   if (!Value && Init->EvaluateAsRValue(EvalResult, getContext()) &&
6411       !EvalResult.hasSideEffects())
6412     Value = &EvalResult.Val;
6413 
6414   LangAS AddrSpace =
6415       VD ? GetGlobalVarAddressSpace(VD) : MaterializedType.getAddressSpace();
6416 
6417   std::optional<ConstantEmitter> emitter;
6418   llvm::Constant *InitialValue = nullptr;
6419   bool Constant = false;
6420   llvm::Type *Type;
6421   if (Value) {
6422     // The temporary has a constant initializer, use it.
6423     emitter.emplace(*this);
6424     InitialValue = emitter->emitForInitializer(*Value, AddrSpace,
6425                                                MaterializedType);
6426     Constant =
6427         MaterializedType.isConstantStorage(getContext(), /*ExcludeCtor*/ Value,
6428                                            /*ExcludeDtor*/ false);
6429     Type = InitialValue->getType();
6430   } else {
6431     // No initializer, the initialization will be provided when we
6432     // initialize the declaration which performed lifetime extension.
6433     Type = getTypes().ConvertTypeForMem(MaterializedType);
6434   }
6435 
6436   // Create a global variable for this lifetime-extended temporary.
6437   llvm::GlobalValue::LinkageTypes Linkage = getLLVMLinkageVarDefinition(VD);
6438   if (Linkage == llvm::GlobalVariable::ExternalLinkage) {
6439     const VarDecl *InitVD;
6440     if (VD->isStaticDataMember() && VD->getAnyInitializer(InitVD) &&
6441         isa<CXXRecordDecl>(InitVD->getLexicalDeclContext())) {
6442       // Temporaries defined inside a class get linkonce_odr linkage because the
6443       // class can be defined in multiple translation units.
6444       Linkage = llvm::GlobalVariable::LinkOnceODRLinkage;
6445     } else {
6446       // There is no need for this temporary to have external linkage if the
6447       // VarDecl has external linkage.
6448       Linkage = llvm::GlobalVariable::InternalLinkage;
6449     }
6450   }
6451   auto TargetAS = getContext().getTargetAddressSpace(AddrSpace);
6452   auto *GV = new llvm::GlobalVariable(
6453       getModule(), Type, Constant, Linkage, InitialValue, Name.c_str(),
6454       /*InsertBefore=*/nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
6455   if (emitter) emitter->finalize(GV);
6456   // Don't assign dllimport or dllexport to local linkage globals.
6457   if (!llvm::GlobalValue::isLocalLinkage(Linkage)) {
6458     setGVProperties(GV, VD);
6459     if (GV->getDLLStorageClass() == llvm::GlobalVariable::DLLExportStorageClass)
6460       // The reference temporary should never be dllexport.
6461       GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
6462   }
6463   GV->setAlignment(Align.getAsAlign());
6464   if (supportsCOMDAT() && GV->isWeakForLinker())
6465     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
6466   if (VD->getTLSKind())
6467     setTLSMode(GV, *VD);
6468   llvm::Constant *CV = GV;
6469   if (AddrSpace != LangAS::Default)
6470     CV = getTargetCodeGenInfo().performAddrSpaceCast(
6471         *this, GV, AddrSpace, LangAS::Default,
6472         llvm::PointerType::get(
6473             getLLVMContext(),
6474             getContext().getTargetAddressSpace(LangAS::Default)));
6475 
6476   // Update the map with the new temporary. If we created a placeholder above,
6477   // replace it with the new global now.
6478   llvm::Constant *&Entry = MaterializedGlobalTemporaryMap[E];
6479   if (Entry) {
6480     Entry->replaceAllUsesWith(CV);
6481     llvm::cast<llvm::GlobalVariable>(Entry)->eraseFromParent();
6482   }
6483   Entry = CV;
6484 
6485   return ConstantAddress(CV, Type, Align);
6486 }
6487 
6488 /// EmitObjCPropertyImplementations - Emit information for synthesized
6489 /// properties for an implementation.
6490 void CodeGenModule::EmitObjCPropertyImplementations(const
6491                                                     ObjCImplementationDecl *D) {
6492   for (const auto *PID : D->property_impls()) {
6493     // Dynamic is just for type-checking.
6494     if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
6495       ObjCPropertyDecl *PD = PID->getPropertyDecl();
6496 
6497       // Determine which methods need to be implemented, some may have
6498       // been overridden. Note that ::isPropertyAccessor is not the method
6499       // we want, that just indicates if the decl came from a
6500       // property. What we want to know is if the method is defined in
6501       // this implementation.
6502       auto *Getter = PID->getGetterMethodDecl();
6503       if (!Getter || Getter->isSynthesizedAccessorStub())
6504         CodeGenFunction(*this).GenerateObjCGetter(
6505             const_cast<ObjCImplementationDecl *>(D), PID);
6506       auto *Setter = PID->getSetterMethodDecl();
6507       if (!PD->isReadOnly() && (!Setter || Setter->isSynthesizedAccessorStub()))
6508         CodeGenFunction(*this).GenerateObjCSetter(
6509                                  const_cast<ObjCImplementationDecl *>(D), PID);
6510     }
6511   }
6512 }
6513 
6514 static bool needsDestructMethod(ObjCImplementationDecl *impl) {
6515   const ObjCInterfaceDecl *iface = impl->getClassInterface();
6516   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
6517        ivar; ivar = ivar->getNextIvar())
6518     if (ivar->getType().isDestructedType())
6519       return true;
6520 
6521   return false;
6522 }
6523 
6524 static bool AllTrivialInitializers(CodeGenModule &CGM,
6525                                    ObjCImplementationDecl *D) {
6526   CodeGenFunction CGF(CGM);
6527   for (ObjCImplementationDecl::init_iterator B = D->init_begin(),
6528        E = D->init_end(); B != E; ++B) {
6529     CXXCtorInitializer *CtorInitExp = *B;
6530     Expr *Init = CtorInitExp->getInit();
6531     if (!CGF.isTrivialInitializer(Init))
6532       return false;
6533   }
6534   return true;
6535 }
6536 
6537 /// EmitObjCIvarInitializations - Emit information for ivar initialization
6538 /// for an implementation.
6539 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
6540   // We might need a .cxx_destruct even if we don't have any ivar initializers.
6541   if (needsDestructMethod(D)) {
6542     IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct");
6543     Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
6544     ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(
6545         getContext(), D->getLocation(), D->getLocation(), cxxSelector,
6546         getContext().VoidTy, nullptr, D,
6547         /*isInstance=*/true, /*isVariadic=*/false,
6548         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
6549         /*isImplicitlyDeclared=*/true,
6550         /*isDefined=*/false, ObjCImplementationControl::Required);
6551     D->addInstanceMethod(DTORMethod);
6552     CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false);
6553     D->setHasDestructors(true);
6554   }
6555 
6556   // If the implementation doesn't have any ivar initializers, we don't need
6557   // a .cxx_construct.
6558   if (D->getNumIvarInitializers() == 0 ||
6559       AllTrivialInitializers(*this, D))
6560     return;
6561 
6562   IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
6563   Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
6564   // The constructor returns 'self'.
6565   ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(
6566       getContext(), D->getLocation(), D->getLocation(), cxxSelector,
6567       getContext().getObjCIdType(), nullptr, D, /*isInstance=*/true,
6568       /*isVariadic=*/false,
6569       /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
6570       /*isImplicitlyDeclared=*/true,
6571       /*isDefined=*/false, ObjCImplementationControl::Required);
6572   D->addInstanceMethod(CTORMethod);
6573   CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true);
6574   D->setHasNonZeroConstructors(true);
6575 }
6576 
6577 // EmitLinkageSpec - Emit all declarations in a linkage spec.
6578 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
6579   if (LSD->getLanguage() != LinkageSpecLanguageIDs::C &&
6580       LSD->getLanguage() != LinkageSpecLanguageIDs::CXX) {
6581     ErrorUnsupported(LSD, "linkage spec");
6582     return;
6583   }
6584 
6585   EmitDeclContext(LSD);
6586 }
6587 
6588 void CodeGenModule::EmitTopLevelStmt(const TopLevelStmtDecl *D) {
6589   // Device code should not be at top level.
6590   if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
6591     return;
6592 
6593   std::unique_ptr<CodeGenFunction> &CurCGF =
6594       GlobalTopLevelStmtBlockInFlight.first;
6595 
6596   // We emitted a top-level stmt but after it there is initialization.
6597   // Stop squashing the top-level stmts into a single function.
6598   if (CurCGF && CXXGlobalInits.back() != CurCGF->CurFn) {
6599     CurCGF->FinishFunction(D->getEndLoc());
6600     CurCGF = nullptr;
6601   }
6602 
6603   if (!CurCGF) {
6604     // void __stmts__N(void)
6605     // FIXME: Ask the ABI name mangler to pick a name.
6606     std::string Name = "__stmts__" + llvm::utostr(CXXGlobalInits.size());
6607     FunctionArgList Args;
6608     QualType RetTy = getContext().VoidTy;
6609     const CGFunctionInfo &FnInfo =
6610         getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
6611     llvm::FunctionType *FnTy = getTypes().GetFunctionType(FnInfo);
6612     llvm::Function *Fn = llvm::Function::Create(
6613         FnTy, llvm::GlobalValue::InternalLinkage, Name, &getModule());
6614 
6615     CurCGF.reset(new CodeGenFunction(*this));
6616     GlobalTopLevelStmtBlockInFlight.second = D;
6617     CurCGF->StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
6618                           D->getBeginLoc(), D->getBeginLoc());
6619     CXXGlobalInits.push_back(Fn);
6620   }
6621 
6622   CurCGF->EmitStmt(D->getStmt());
6623 }
6624 
6625 void CodeGenModule::EmitDeclContext(const DeclContext *DC) {
6626   for (auto *I : DC->decls()) {
6627     // Unlike other DeclContexts, the contents of an ObjCImplDecl at TU scope
6628     // are themselves considered "top-level", so EmitTopLevelDecl on an
6629     // ObjCImplDecl does not recursively visit them. We need to do that in
6630     // case they're nested inside another construct (LinkageSpecDecl /
6631     // ExportDecl) that does stop them from being considered "top-level".
6632     if (auto *OID = dyn_cast<ObjCImplDecl>(I)) {
6633       for (auto *M : OID->methods())
6634         EmitTopLevelDecl(M);
6635     }
6636 
6637     EmitTopLevelDecl(I);
6638   }
6639 }
6640 
6641 /// EmitTopLevelDecl - Emit code for a single top level declaration.
6642 void CodeGenModule::EmitTopLevelDecl(Decl *D) {
6643   // Ignore dependent declarations.
6644   if (D->isTemplated())
6645     return;
6646 
6647   // Consteval function shouldn't be emitted.
6648   if (auto *FD = dyn_cast<FunctionDecl>(D); FD && FD->isImmediateFunction())
6649     return;
6650 
6651   switch (D->getKind()) {
6652   case Decl::CXXConversion:
6653   case Decl::CXXMethod:
6654   case Decl::Function:
6655     EmitGlobal(cast<FunctionDecl>(D));
6656     // Always provide some coverage mapping
6657     // even for the functions that aren't emitted.
6658     AddDeferredUnusedCoverageMapping(D);
6659     break;
6660 
6661   case Decl::CXXDeductionGuide:
6662     // Function-like, but does not result in code emission.
6663     break;
6664 
6665   case Decl::Var:
6666   case Decl::Decomposition:
6667   case Decl::VarTemplateSpecialization:
6668     EmitGlobal(cast<VarDecl>(D));
6669     if (auto *DD = dyn_cast<DecompositionDecl>(D))
6670       for (auto *B : DD->bindings())
6671         if (auto *HD = B->getHoldingVar())
6672           EmitGlobal(HD);
6673     break;
6674 
6675   // Indirect fields from global anonymous structs and unions can be
6676   // ignored; only the actual variable requires IR gen support.
6677   case Decl::IndirectField:
6678     break;
6679 
6680   // C++ Decls
6681   case Decl::Namespace:
6682     EmitDeclContext(cast<NamespaceDecl>(D));
6683     break;
6684   case Decl::ClassTemplateSpecialization: {
6685     const auto *Spec = cast<ClassTemplateSpecializationDecl>(D);
6686     if (CGDebugInfo *DI = getModuleDebugInfo())
6687       if (Spec->getSpecializationKind() ==
6688               TSK_ExplicitInstantiationDefinition &&
6689           Spec->hasDefinition())
6690         DI->completeTemplateDefinition(*Spec);
6691   } [[fallthrough]];
6692   case Decl::CXXRecord: {
6693     CXXRecordDecl *CRD = cast<CXXRecordDecl>(D);
6694     if (CGDebugInfo *DI = getModuleDebugInfo()) {
6695       if (CRD->hasDefinition())
6696         DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
6697       if (auto *ES = D->getASTContext().getExternalSource())
6698         if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
6699           DI->completeUnusedClass(*CRD);
6700     }
6701     // Emit any static data members, they may be definitions.
6702     for (auto *I : CRD->decls())
6703       if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))
6704         EmitTopLevelDecl(I);
6705     break;
6706   }
6707     // No code generation needed.
6708   case Decl::UsingShadow:
6709   case Decl::ClassTemplate:
6710   case Decl::VarTemplate:
6711   case Decl::Concept:
6712   case Decl::VarTemplatePartialSpecialization:
6713   case Decl::FunctionTemplate:
6714   case Decl::TypeAliasTemplate:
6715   case Decl::Block:
6716   case Decl::Empty:
6717   case Decl::Binding:
6718     break;
6719   case Decl::Using:          // using X; [C++]
6720     if (CGDebugInfo *DI = getModuleDebugInfo())
6721         DI->EmitUsingDecl(cast<UsingDecl>(*D));
6722     break;
6723   case Decl::UsingEnum: // using enum X; [C++]
6724     if (CGDebugInfo *DI = getModuleDebugInfo())
6725       DI->EmitUsingEnumDecl(cast<UsingEnumDecl>(*D));
6726     break;
6727   case Decl::NamespaceAlias:
6728     if (CGDebugInfo *DI = getModuleDebugInfo())
6729         DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(*D));
6730     break;
6731   case Decl::UsingDirective: // using namespace X; [C++]
6732     if (CGDebugInfo *DI = getModuleDebugInfo())
6733       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D));
6734     break;
6735   case Decl::CXXConstructor:
6736     getCXXABI().EmitCXXConstructors(cast<CXXConstructorDecl>(D));
6737     break;
6738   case Decl::CXXDestructor:
6739     getCXXABI().EmitCXXDestructors(cast<CXXDestructorDecl>(D));
6740     break;
6741 
6742   case Decl::StaticAssert:
6743     // Nothing to do.
6744     break;
6745 
6746   // Objective-C Decls
6747 
6748   // Forward declarations, no (immediate) code generation.
6749   case Decl::ObjCInterface:
6750   case Decl::ObjCCategory:
6751     break;
6752 
6753   case Decl::ObjCProtocol: {
6754     auto *Proto = cast<ObjCProtocolDecl>(D);
6755     if (Proto->isThisDeclarationADefinition())
6756       ObjCRuntime->GenerateProtocol(Proto);
6757     break;
6758   }
6759 
6760   case Decl::ObjCCategoryImpl:
6761     // Categories have properties but don't support synthesize so we
6762     // can ignore them here.
6763     ObjCRuntime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
6764     break;
6765 
6766   case Decl::ObjCImplementation: {
6767     auto *OMD = cast<ObjCImplementationDecl>(D);
6768     EmitObjCPropertyImplementations(OMD);
6769     EmitObjCIvarInitializations(OMD);
6770     ObjCRuntime->GenerateClass(OMD);
6771     // Emit global variable debug information.
6772     if (CGDebugInfo *DI = getModuleDebugInfo())
6773       if (getCodeGenOpts().hasReducedDebugInfo())
6774         DI->getOrCreateInterfaceType(getContext().getObjCInterfaceType(
6775             OMD->getClassInterface()), OMD->getLocation());
6776     break;
6777   }
6778   case Decl::ObjCMethod: {
6779     auto *OMD = cast<ObjCMethodDecl>(D);
6780     // If this is not a prototype, emit the body.
6781     if (OMD->getBody())
6782       CodeGenFunction(*this).GenerateObjCMethod(OMD);
6783     break;
6784   }
6785   case Decl::ObjCCompatibleAlias:
6786     ObjCRuntime->RegisterAlias(cast<ObjCCompatibleAliasDecl>(D));
6787     break;
6788 
6789   case Decl::PragmaComment: {
6790     const auto *PCD = cast<PragmaCommentDecl>(D);
6791     switch (PCD->getCommentKind()) {
6792     case PCK_Unknown:
6793       llvm_unreachable("unexpected pragma comment kind");
6794     case PCK_Linker:
6795       AppendLinkerOptions(PCD->getArg());
6796       break;
6797     case PCK_Lib:
6798         AddDependentLib(PCD->getArg());
6799       break;
6800     case PCK_Compiler:
6801     case PCK_ExeStr:
6802     case PCK_User:
6803       break; // We ignore all of these.
6804     }
6805     break;
6806   }
6807 
6808   case Decl::PragmaDetectMismatch: {
6809     const auto *PDMD = cast<PragmaDetectMismatchDecl>(D);
6810     AddDetectMismatch(PDMD->getName(), PDMD->getValue());
6811     break;
6812   }
6813 
6814   case Decl::LinkageSpec:
6815     EmitLinkageSpec(cast<LinkageSpecDecl>(D));
6816     break;
6817 
6818   case Decl::FileScopeAsm: {
6819     // File-scope asm is ignored during device-side CUDA compilation.
6820     if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
6821       break;
6822     // File-scope asm is ignored during device-side OpenMP compilation.
6823     if (LangOpts.OpenMPIsTargetDevice)
6824       break;
6825     // File-scope asm is ignored during device-side SYCL compilation.
6826     if (LangOpts.SYCLIsDevice)
6827       break;
6828     auto *AD = cast<FileScopeAsmDecl>(D);
6829     getModule().appendModuleInlineAsm(AD->getAsmString()->getString());
6830     break;
6831   }
6832 
6833   case Decl::TopLevelStmt:
6834     EmitTopLevelStmt(cast<TopLevelStmtDecl>(D));
6835     break;
6836 
6837   case Decl::Import: {
6838     auto *Import = cast<ImportDecl>(D);
6839 
6840     // If we've already imported this module, we're done.
6841     if (!ImportedModules.insert(Import->getImportedModule()))
6842       break;
6843 
6844     // Emit debug information for direct imports.
6845     if (!Import->getImportedOwningModule()) {
6846       if (CGDebugInfo *DI = getModuleDebugInfo())
6847         DI->EmitImportDecl(*Import);
6848     }
6849 
6850     // For C++ standard modules we are done - we will call the module
6851     // initializer for imported modules, and that will likewise call those for
6852     // any imports it has.
6853     if (CXX20ModuleInits && Import->getImportedOwningModule() &&
6854         !Import->getImportedOwningModule()->isModuleMapModule())
6855       break;
6856 
6857     // For clang C++ module map modules the initializers for sub-modules are
6858     // emitted here.
6859 
6860     // Find all of the submodules and emit the module initializers.
6861     llvm::SmallPtrSet<clang::Module *, 16> Visited;
6862     SmallVector<clang::Module *, 16> Stack;
6863     Visited.insert(Import->getImportedModule());
6864     Stack.push_back(Import->getImportedModule());
6865 
6866     while (!Stack.empty()) {
6867       clang::Module *Mod = Stack.pop_back_val();
6868       if (!EmittedModuleInitializers.insert(Mod).second)
6869         continue;
6870 
6871       for (auto *D : Context.getModuleInitializers(Mod))
6872         EmitTopLevelDecl(D);
6873 
6874       // Visit the submodules of this module.
6875       for (auto *Submodule : Mod->submodules()) {
6876         // Skip explicit children; they need to be explicitly imported to emit
6877         // the initializers.
6878         if (Submodule->IsExplicit)
6879           continue;
6880 
6881         if (Visited.insert(Submodule).second)
6882           Stack.push_back(Submodule);
6883       }
6884     }
6885     break;
6886   }
6887 
6888   case Decl::Export:
6889     EmitDeclContext(cast<ExportDecl>(D));
6890     break;
6891 
6892   case Decl::OMPThreadPrivate:
6893     EmitOMPThreadPrivateDecl(cast<OMPThreadPrivateDecl>(D));
6894     break;
6895 
6896   case Decl::OMPAllocate:
6897     EmitOMPAllocateDecl(cast<OMPAllocateDecl>(D));
6898     break;
6899 
6900   case Decl::OMPDeclareReduction:
6901     EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(D));
6902     break;
6903 
6904   case Decl::OMPDeclareMapper:
6905     EmitOMPDeclareMapper(cast<OMPDeclareMapperDecl>(D));
6906     break;
6907 
6908   case Decl::OMPRequires:
6909     EmitOMPRequiresDecl(cast<OMPRequiresDecl>(D));
6910     break;
6911 
6912   case Decl::Typedef:
6913   case Decl::TypeAlias: // using foo = bar; [C++11]
6914     if (CGDebugInfo *DI = getModuleDebugInfo())
6915       DI->EmitAndRetainType(
6916           getContext().getTypedefType(cast<TypedefNameDecl>(D)));
6917     break;
6918 
6919   case Decl::Record:
6920     if (CGDebugInfo *DI = getModuleDebugInfo())
6921       if (cast<RecordDecl>(D)->getDefinition())
6922         DI->EmitAndRetainType(getContext().getRecordType(cast<RecordDecl>(D)));
6923     break;
6924 
6925   case Decl::Enum:
6926     if (CGDebugInfo *DI = getModuleDebugInfo())
6927       if (cast<EnumDecl>(D)->getDefinition())
6928         DI->EmitAndRetainType(getContext().getEnumType(cast<EnumDecl>(D)));
6929     break;
6930 
6931   case Decl::HLSLBuffer:
6932     getHLSLRuntime().addBuffer(cast<HLSLBufferDecl>(D));
6933     break;
6934 
6935   default:
6936     // Make sure we handled everything we should, every other kind is a
6937     // non-top-level decl.  FIXME: Would be nice to have an isTopLevelDeclKind
6938     // function. Need to recode Decl::Kind to do that easily.
6939     assert(isa<TypeDecl>(D) && "Unsupported decl kind");
6940     break;
6941   }
6942 }
6943 
6944 void CodeGenModule::AddDeferredUnusedCoverageMapping(Decl *D) {
6945   // Do we need to generate coverage mapping?
6946   if (!CodeGenOpts.CoverageMapping)
6947     return;
6948   switch (D->getKind()) {
6949   case Decl::CXXConversion:
6950   case Decl::CXXMethod:
6951   case Decl::Function:
6952   case Decl::ObjCMethod:
6953   case Decl::CXXConstructor:
6954   case Decl::CXXDestructor: {
6955     if (!cast<FunctionDecl>(D)->doesThisDeclarationHaveABody())
6956       break;
6957     SourceManager &SM = getContext().getSourceManager();
6958     if (LimitedCoverage && SM.getMainFileID() != SM.getFileID(D->getBeginLoc()))
6959       break;
6960     DeferredEmptyCoverageMappingDecls.try_emplace(D, true);
6961     break;
6962   }
6963   default:
6964     break;
6965   };
6966 }
6967 
6968 void CodeGenModule::ClearUnusedCoverageMapping(const Decl *D) {
6969   // Do we need to generate coverage mapping?
6970   if (!CodeGenOpts.CoverageMapping)
6971     return;
6972   if (const auto *Fn = dyn_cast<FunctionDecl>(D)) {
6973     if (Fn->isTemplateInstantiation())
6974       ClearUnusedCoverageMapping(Fn->getTemplateInstantiationPattern());
6975   }
6976   DeferredEmptyCoverageMappingDecls.insert_or_assign(D, false);
6977 }
6978 
6979 void CodeGenModule::EmitDeferredUnusedCoverageMappings() {
6980   // We call takeVector() here to avoid use-after-free.
6981   // FIXME: DeferredEmptyCoverageMappingDecls is getting mutated because
6982   // we deserialize function bodies to emit coverage info for them, and that
6983   // deserializes more declarations. How should we handle that case?
6984   for (const auto &Entry : DeferredEmptyCoverageMappingDecls.takeVector()) {
6985     if (!Entry.second)
6986       continue;
6987     const Decl *D = Entry.first;
6988     switch (D->getKind()) {
6989     case Decl::CXXConversion:
6990     case Decl::CXXMethod:
6991     case Decl::Function:
6992     case Decl::ObjCMethod: {
6993       CodeGenPGO PGO(*this);
6994       GlobalDecl GD(cast<FunctionDecl>(D));
6995       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
6996                                   getFunctionLinkage(GD));
6997       break;
6998     }
6999     case Decl::CXXConstructor: {
7000       CodeGenPGO PGO(*this);
7001       GlobalDecl GD(cast<CXXConstructorDecl>(D), Ctor_Base);
7002       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
7003                                   getFunctionLinkage(GD));
7004       break;
7005     }
7006     case Decl::CXXDestructor: {
7007       CodeGenPGO PGO(*this);
7008       GlobalDecl GD(cast<CXXDestructorDecl>(D), Dtor_Base);
7009       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
7010                                   getFunctionLinkage(GD));
7011       break;
7012     }
7013     default:
7014       break;
7015     };
7016   }
7017 }
7018 
7019 void CodeGenModule::EmitMainVoidAlias() {
7020   // In order to transition away from "__original_main" gracefully, emit an
7021   // alias for "main" in the no-argument case so that libc can detect when
7022   // new-style no-argument main is in used.
7023   if (llvm::Function *F = getModule().getFunction("main")) {
7024     if (!F->isDeclaration() && F->arg_size() == 0 && !F->isVarArg() &&
7025         F->getReturnType()->isIntegerTy(Context.getTargetInfo().getIntWidth())) {
7026       auto *GA = llvm::GlobalAlias::create("__main_void", F);
7027       GA->setVisibility(llvm::GlobalValue::HiddenVisibility);
7028     }
7029   }
7030 }
7031 
7032 /// Turns the given pointer into a constant.
7033 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context,
7034                                           const void *Ptr) {
7035   uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr);
7036   llvm::Type *i64 = llvm::Type::getInt64Ty(Context);
7037   return llvm::ConstantInt::get(i64, PtrInt);
7038 }
7039 
7040 static void EmitGlobalDeclMetadata(CodeGenModule &CGM,
7041                                    llvm::NamedMDNode *&GlobalMetadata,
7042                                    GlobalDecl D,
7043                                    llvm::GlobalValue *Addr) {
7044   if (!GlobalMetadata)
7045     GlobalMetadata =
7046       CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs");
7047 
7048   // TODO: should we report variant information for ctors/dtors?
7049   llvm::Metadata *Ops[] = {llvm::ConstantAsMetadata::get(Addr),
7050                            llvm::ConstantAsMetadata::get(GetPointerConstant(
7051                                CGM.getLLVMContext(), D.getDecl()))};
7052   GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
7053 }
7054 
7055 bool CodeGenModule::CheckAndReplaceExternCIFuncs(llvm::GlobalValue *Elem,
7056                                                  llvm::GlobalValue *CppFunc) {
7057   // Store the list of ifuncs we need to replace uses in.
7058   llvm::SmallVector<llvm::GlobalIFunc *> IFuncs;
7059   // List of ConstantExprs that we should be able to delete when we're done
7060   // here.
7061   llvm::SmallVector<llvm::ConstantExpr *> CEs;
7062 
7063   // It isn't valid to replace the extern-C ifuncs if all we find is itself!
7064   if (Elem == CppFunc)
7065     return false;
7066 
7067   // First make sure that all users of this are ifuncs (or ifuncs via a
7068   // bitcast), and collect the list of ifuncs and CEs so we can work on them
7069   // later.
7070   for (llvm::User *User : Elem->users()) {
7071     // Users can either be a bitcast ConstExpr that is used by the ifuncs, OR an
7072     // ifunc directly. In any other case, just give up, as we don't know what we
7073     // could break by changing those.
7074     if (auto *ConstExpr = dyn_cast<llvm::ConstantExpr>(User)) {
7075       if (ConstExpr->getOpcode() != llvm::Instruction::BitCast)
7076         return false;
7077 
7078       for (llvm::User *CEUser : ConstExpr->users()) {
7079         if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(CEUser)) {
7080           IFuncs.push_back(IFunc);
7081         } else {
7082           return false;
7083         }
7084       }
7085       CEs.push_back(ConstExpr);
7086     } else if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(User)) {
7087       IFuncs.push_back(IFunc);
7088     } else {
7089       // This user is one we don't know how to handle, so fail redirection. This
7090       // will result in an ifunc retaining a resolver name that will ultimately
7091       // fail to be resolved to a defined function.
7092       return false;
7093     }
7094   }
7095 
7096   // Now we know this is a valid case where we can do this alias replacement, we
7097   // need to remove all of the references to Elem (and the bitcasts!) so we can
7098   // delete it.
7099   for (llvm::GlobalIFunc *IFunc : IFuncs)
7100     IFunc->setResolver(nullptr);
7101   for (llvm::ConstantExpr *ConstExpr : CEs)
7102     ConstExpr->destroyConstant();
7103 
7104   // We should now be out of uses for the 'old' version of this function, so we
7105   // can erase it as well.
7106   Elem->eraseFromParent();
7107 
7108   for (llvm::GlobalIFunc *IFunc : IFuncs) {
7109     // The type of the resolver is always just a function-type that returns the
7110     // type of the IFunc, so create that here. If the type of the actual
7111     // resolver doesn't match, it just gets bitcast to the right thing.
7112     auto *ResolverTy =
7113         llvm::FunctionType::get(IFunc->getType(), /*isVarArg*/ false);
7114     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
7115         CppFunc->getName(), ResolverTy, {}, /*ForVTable*/ false);
7116     IFunc->setResolver(Resolver);
7117   }
7118   return true;
7119 }
7120 
7121 /// For each function which is declared within an extern "C" region and marked
7122 /// as 'used', but has internal linkage, create an alias from the unmangled
7123 /// name to the mangled name if possible. People expect to be able to refer
7124 /// to such functions with an unmangled name from inline assembly within the
7125 /// same translation unit.
7126 void CodeGenModule::EmitStaticExternCAliases() {
7127   if (!getTargetCodeGenInfo().shouldEmitStaticExternCAliases())
7128     return;
7129   for (auto &I : StaticExternCValues) {
7130     IdentifierInfo *Name = I.first;
7131     llvm::GlobalValue *Val = I.second;
7132 
7133     // If Val is null, that implies there were multiple declarations that each
7134     // had a claim to the unmangled name. In this case, generation of the alias
7135     // is suppressed. See CodeGenModule::MaybeHandleStaticInExternC.
7136     if (!Val)
7137       break;
7138 
7139     llvm::GlobalValue *ExistingElem =
7140         getModule().getNamedValue(Name->getName());
7141 
7142     // If there is either not something already by this name, or we were able to
7143     // replace all uses from IFuncs, create the alias.
7144     if (!ExistingElem || CheckAndReplaceExternCIFuncs(ExistingElem, Val))
7145       addCompilerUsedGlobal(llvm::GlobalAlias::create(Name->getName(), Val));
7146   }
7147 }
7148 
7149 bool CodeGenModule::lookupRepresentativeDecl(StringRef MangledName,
7150                                              GlobalDecl &Result) const {
7151   auto Res = Manglings.find(MangledName);
7152   if (Res == Manglings.end())
7153     return false;
7154   Result = Res->getValue();
7155   return true;
7156 }
7157 
7158 /// Emits metadata nodes associating all the global values in the
7159 /// current module with the Decls they came from.  This is useful for
7160 /// projects using IR gen as a subroutine.
7161 ///
7162 /// Since there's currently no way to associate an MDNode directly
7163 /// with an llvm::GlobalValue, we create a global named metadata
7164 /// with the name 'clang.global.decl.ptrs'.
7165 void CodeGenModule::EmitDeclMetadata() {
7166   llvm::NamedMDNode *GlobalMetadata = nullptr;
7167 
7168   for (auto &I : MangledDeclNames) {
7169     llvm::GlobalValue *Addr = getModule().getNamedValue(I.second);
7170     // Some mangled names don't necessarily have an associated GlobalValue
7171     // in this module, e.g. if we mangled it for DebugInfo.
7172     if (Addr)
7173       EmitGlobalDeclMetadata(*this, GlobalMetadata, I.first, Addr);
7174   }
7175 }
7176 
7177 /// Emits metadata nodes for all the local variables in the current
7178 /// function.
7179 void CodeGenFunction::EmitDeclMetadata() {
7180   if (LocalDeclMap.empty()) return;
7181 
7182   llvm::LLVMContext &Context = getLLVMContext();
7183 
7184   // Find the unique metadata ID for this name.
7185   unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr");
7186 
7187   llvm::NamedMDNode *GlobalMetadata = nullptr;
7188 
7189   for (auto &I : LocalDeclMap) {
7190     const Decl *D = I.first;
7191     llvm::Value *Addr = I.second.getPointer();
7192     if (auto *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) {
7193       llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D);
7194       Alloca->setMetadata(
7195           DeclPtrKind, llvm::MDNode::get(
7196                            Context, llvm::ValueAsMetadata::getConstant(DAddr)));
7197     } else if (auto *GV = dyn_cast<llvm::GlobalValue>(Addr)) {
7198       GlobalDecl GD = GlobalDecl(cast<VarDecl>(D));
7199       EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV);
7200     }
7201   }
7202 }
7203 
7204 void CodeGenModule::EmitVersionIdentMetadata() {
7205   llvm::NamedMDNode *IdentMetadata =
7206     TheModule.getOrInsertNamedMetadata("llvm.ident");
7207   std::string Version = getClangFullVersion();
7208   llvm::LLVMContext &Ctx = TheModule.getContext();
7209 
7210   llvm::Metadata *IdentNode[] = {llvm::MDString::get(Ctx, Version)};
7211   IdentMetadata->addOperand(llvm::MDNode::get(Ctx, IdentNode));
7212 }
7213 
7214 void CodeGenModule::EmitCommandLineMetadata() {
7215   llvm::NamedMDNode *CommandLineMetadata =
7216     TheModule.getOrInsertNamedMetadata("llvm.commandline");
7217   std::string CommandLine = getCodeGenOpts().RecordCommandLine;
7218   llvm::LLVMContext &Ctx = TheModule.getContext();
7219 
7220   llvm::Metadata *CommandLineNode[] = {llvm::MDString::get(Ctx, CommandLine)};
7221   CommandLineMetadata->addOperand(llvm::MDNode::get(Ctx, CommandLineNode));
7222 }
7223 
7224 void CodeGenModule::EmitCoverageFile() {
7225   llvm::NamedMDNode *CUNode = TheModule.getNamedMetadata("llvm.dbg.cu");
7226   if (!CUNode)
7227     return;
7228 
7229   llvm::NamedMDNode *GCov = TheModule.getOrInsertNamedMetadata("llvm.gcov");
7230   llvm::LLVMContext &Ctx = TheModule.getContext();
7231   auto *CoverageDataFile =
7232       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageDataFile);
7233   auto *CoverageNotesFile =
7234       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageNotesFile);
7235   for (int i = 0, e = CUNode->getNumOperands(); i != e; ++i) {
7236     llvm::MDNode *CU = CUNode->getOperand(i);
7237     llvm::Metadata *Elts[] = {CoverageNotesFile, CoverageDataFile, CU};
7238     GCov->addOperand(llvm::MDNode::get(Ctx, Elts));
7239   }
7240 }
7241 
7242 llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
7243                                                        bool ForEH) {
7244   // Return a bogus pointer if RTTI is disabled, unless it's for EH.
7245   // FIXME: should we even be calling this method if RTTI is disabled
7246   // and it's not for EH?
7247   if (!shouldEmitRTTI(ForEH))
7248     return llvm::Constant::getNullValue(GlobalsInt8PtrTy);
7249 
7250   if (ForEH && Ty->isObjCObjectPointerType() &&
7251       LangOpts.ObjCRuntime.isGNUFamily())
7252     return ObjCRuntime->GetEHType(Ty);
7253 
7254   return getCXXABI().getAddrOfRTTIDescriptor(Ty);
7255 }
7256 
7257 void CodeGenModule::EmitOMPThreadPrivateDecl(const OMPThreadPrivateDecl *D) {
7258   // Do not emit threadprivates in simd-only mode.
7259   if (LangOpts.OpenMP && LangOpts.OpenMPSimd)
7260     return;
7261   for (auto RefExpr : D->varlists()) {
7262     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(RefExpr)->getDecl());
7263     bool PerformInit =
7264         VD->getAnyInitializer() &&
7265         !VD->getAnyInitializer()->isConstantInitializer(getContext(),
7266                                                         /*ForRef=*/false);
7267 
7268     Address Addr(GetAddrOfGlobalVar(VD),
7269                  getTypes().ConvertTypeForMem(VD->getType()),
7270                  getContext().getDeclAlign(VD));
7271     if (auto InitFunction = getOpenMPRuntime().emitThreadPrivateVarDefinition(
7272             VD, Addr, RefExpr->getBeginLoc(), PerformInit))
7273       CXXGlobalInits.push_back(InitFunction);
7274   }
7275 }
7276 
7277 llvm::Metadata *
7278 CodeGenModule::CreateMetadataIdentifierImpl(QualType T, MetadataTypeMap &Map,
7279                                             StringRef Suffix) {
7280   if (auto *FnType = T->getAs<FunctionProtoType>())
7281     T = getContext().getFunctionType(
7282         FnType->getReturnType(), FnType->getParamTypes(),
7283         FnType->getExtProtoInfo().withExceptionSpec(EST_None));
7284 
7285   llvm::Metadata *&InternalId = Map[T.getCanonicalType()];
7286   if (InternalId)
7287     return InternalId;
7288 
7289   if (isExternallyVisible(T->getLinkage())) {
7290     std::string OutName;
7291     llvm::raw_string_ostream Out(OutName);
7292     getCXXABI().getMangleContext().mangleCanonicalTypeName(
7293         T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
7294 
7295     if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
7296       Out << ".normalized";
7297 
7298     Out << Suffix;
7299 
7300     InternalId = llvm::MDString::get(getLLVMContext(), Out.str());
7301   } else {
7302     InternalId = llvm::MDNode::getDistinct(getLLVMContext(),
7303                                            llvm::ArrayRef<llvm::Metadata *>());
7304   }
7305 
7306   return InternalId;
7307 }
7308 
7309 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierForType(QualType T) {
7310   return CreateMetadataIdentifierImpl(T, MetadataIdMap, "");
7311 }
7312 
7313 llvm::Metadata *
7314 CodeGenModule::CreateMetadataIdentifierForVirtualMemPtrType(QualType T) {
7315   return CreateMetadataIdentifierImpl(T, VirtualMetadataIdMap, ".virtual");
7316 }
7317 
7318 // Generalize pointer types to a void pointer with the qualifiers of the
7319 // originally pointed-to type, e.g. 'const char *' and 'char * const *'
7320 // generalize to 'const void *' while 'char *' and 'const char **' generalize to
7321 // 'void *'.
7322 static QualType GeneralizeType(ASTContext &Ctx, QualType Ty) {
7323   if (!Ty->isPointerType())
7324     return Ty;
7325 
7326   return Ctx.getPointerType(
7327       QualType(Ctx.VoidTy).withCVRQualifiers(
7328           Ty->getPointeeType().getCVRQualifiers()));
7329 }
7330 
7331 // Apply type generalization to a FunctionType's return and argument types
7332 static QualType GeneralizeFunctionType(ASTContext &Ctx, QualType Ty) {
7333   if (auto *FnType = Ty->getAs<FunctionProtoType>()) {
7334     SmallVector<QualType, 8> GeneralizedParams;
7335     for (auto &Param : FnType->param_types())
7336       GeneralizedParams.push_back(GeneralizeType(Ctx, Param));
7337 
7338     return Ctx.getFunctionType(
7339         GeneralizeType(Ctx, FnType->getReturnType()),
7340         GeneralizedParams, FnType->getExtProtoInfo());
7341   }
7342 
7343   if (auto *FnType = Ty->getAs<FunctionNoProtoType>())
7344     return Ctx.getFunctionNoProtoType(
7345         GeneralizeType(Ctx, FnType->getReturnType()));
7346 
7347   llvm_unreachable("Encountered unknown FunctionType");
7348 }
7349 
7350 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierGeneralized(QualType T) {
7351   return CreateMetadataIdentifierImpl(GeneralizeFunctionType(getContext(), T),
7352                                       GeneralizedMetadataIdMap, ".generalized");
7353 }
7354 
7355 /// Returns whether this module needs the "all-vtables" type identifier.
7356 bool CodeGenModule::NeedAllVtablesTypeId() const {
7357   // Returns true if at least one of vtable-based CFI checkers is enabled and
7358   // is not in the trapping mode.
7359   return ((LangOpts.Sanitize.has(SanitizerKind::CFIVCall) &&
7360            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIVCall)) ||
7361           (LangOpts.Sanitize.has(SanitizerKind::CFINVCall) &&
7362            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFINVCall)) ||
7363           (LangOpts.Sanitize.has(SanitizerKind::CFIDerivedCast) &&
7364            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIDerivedCast)) ||
7365           (LangOpts.Sanitize.has(SanitizerKind::CFIUnrelatedCast) &&
7366            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIUnrelatedCast)));
7367 }
7368 
7369 void CodeGenModule::AddVTableTypeMetadata(llvm::GlobalVariable *VTable,
7370                                           CharUnits Offset,
7371                                           const CXXRecordDecl *RD) {
7372   llvm::Metadata *MD =
7373       CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
7374   VTable->addTypeMetadata(Offset.getQuantity(), MD);
7375 
7376   if (CodeGenOpts.SanitizeCfiCrossDso)
7377     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
7378       VTable->addTypeMetadata(Offset.getQuantity(),
7379                               llvm::ConstantAsMetadata::get(CrossDsoTypeId));
7380 
7381   if (NeedAllVtablesTypeId()) {
7382     llvm::Metadata *MD = llvm::MDString::get(getLLVMContext(), "all-vtables");
7383     VTable->addTypeMetadata(Offset.getQuantity(), MD);
7384   }
7385 }
7386 
7387 llvm::SanitizerStatReport &CodeGenModule::getSanStats() {
7388   if (!SanStats)
7389     SanStats = std::make_unique<llvm::SanitizerStatReport>(&getModule());
7390 
7391   return *SanStats;
7392 }
7393 
7394 llvm::Value *
7395 CodeGenModule::createOpenCLIntToSamplerConversion(const Expr *E,
7396                                                   CodeGenFunction &CGF) {
7397   llvm::Constant *C = ConstantEmitter(CGF).emitAbstract(E, E->getType());
7398   auto *SamplerT = getOpenCLRuntime().getSamplerType(E->getType().getTypePtr());
7399   auto *FTy = llvm::FunctionType::get(SamplerT, {C->getType()}, false);
7400   auto *Call = CGF.EmitRuntimeCall(
7401       CreateRuntimeFunction(FTy, "__translate_sampler_initializer"), {C});
7402   return Call;
7403 }
7404 
7405 CharUnits CodeGenModule::getNaturalPointeeTypeAlignment(
7406     QualType T, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) {
7407   return getNaturalTypeAlignment(T->getPointeeType(), BaseInfo, TBAAInfo,
7408                                  /* forPointeeType= */ true);
7409 }
7410 
7411 CharUnits CodeGenModule::getNaturalTypeAlignment(QualType T,
7412                                                  LValueBaseInfo *BaseInfo,
7413                                                  TBAAAccessInfo *TBAAInfo,
7414                                                  bool forPointeeType) {
7415   if (TBAAInfo)
7416     *TBAAInfo = getTBAAAccessInfo(T);
7417 
7418   // FIXME: This duplicates logic in ASTContext::getTypeAlignIfKnown. But
7419   // that doesn't return the information we need to compute BaseInfo.
7420 
7421   // Honor alignment typedef attributes even on incomplete types.
7422   // We also honor them straight for C++ class types, even as pointees;
7423   // there's an expressivity gap here.
7424   if (auto TT = T->getAs<TypedefType>()) {
7425     if (auto Align = TT->getDecl()->getMaxAlignment()) {
7426       if (BaseInfo)
7427         *BaseInfo = LValueBaseInfo(AlignmentSource::AttributedType);
7428       return getContext().toCharUnitsFromBits(Align);
7429     }
7430   }
7431 
7432   bool AlignForArray = T->isArrayType();
7433 
7434   // Analyze the base element type, so we don't get confused by incomplete
7435   // array types.
7436   T = getContext().getBaseElementType(T);
7437 
7438   if (T->isIncompleteType()) {
7439     // We could try to replicate the logic from
7440     // ASTContext::getTypeAlignIfKnown, but nothing uses the alignment if the
7441     // type is incomplete, so it's impossible to test. We could try to reuse
7442     // getTypeAlignIfKnown, but that doesn't return the information we need
7443     // to set BaseInfo.  So just ignore the possibility that the alignment is
7444     // greater than one.
7445     if (BaseInfo)
7446       *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
7447     return CharUnits::One();
7448   }
7449 
7450   if (BaseInfo)
7451     *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
7452 
7453   CharUnits Alignment;
7454   const CXXRecordDecl *RD;
7455   if (T.getQualifiers().hasUnaligned()) {
7456     Alignment = CharUnits::One();
7457   } else if (forPointeeType && !AlignForArray &&
7458              (RD = T->getAsCXXRecordDecl())) {
7459     // For C++ class pointees, we don't know whether we're pointing at a
7460     // base or a complete object, so we generally need to use the
7461     // non-virtual alignment.
7462     Alignment = getClassPointerAlignment(RD);
7463   } else {
7464     Alignment = getContext().getTypeAlignInChars(T);
7465   }
7466 
7467   // Cap to the global maximum type alignment unless the alignment
7468   // was somehow explicit on the type.
7469   if (unsigned MaxAlign = getLangOpts().MaxTypeAlign) {
7470     if (Alignment.getQuantity() > MaxAlign &&
7471         !getContext().isAlignmentRequired(T))
7472       Alignment = CharUnits::fromQuantity(MaxAlign);
7473   }
7474   return Alignment;
7475 }
7476 
7477 bool CodeGenModule::stopAutoInit() {
7478   unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter;
7479   if (StopAfter) {
7480     // This number is positive only when -ftrivial-auto-var-init-stop-after=* is
7481     // used
7482     if (NumAutoVarInit >= StopAfter) {
7483       return true;
7484     }
7485     if (!NumAutoVarInit) {
7486       unsigned DiagID = getDiags().getCustomDiagID(
7487           DiagnosticsEngine::Warning,
7488           "-ftrivial-auto-var-init-stop-after=%0 has been enabled to limit the "
7489           "number of times ftrivial-auto-var-init=%1 gets applied.");
7490       getDiags().Report(DiagID)
7491           << StopAfter
7492           << (getContext().getLangOpts().getTrivialAutoVarInit() ==
7493                       LangOptions::TrivialAutoVarInitKind::Zero
7494                   ? "zero"
7495                   : "pattern");
7496     }
7497     ++NumAutoVarInit;
7498   }
7499   return false;
7500 }
7501 
7502 void CodeGenModule::printPostfixForExternalizedDecl(llvm::raw_ostream &OS,
7503                                                     const Decl *D) const {
7504   // ptxas does not allow '.' in symbol names. On the other hand, HIP prefers
7505   // postfix beginning with '.' since the symbol name can be demangled.
7506   if (LangOpts.HIP)
7507     OS << (isa<VarDecl>(D) ? ".static." : ".intern.");
7508   else
7509     OS << (isa<VarDecl>(D) ? "__static__" : "__intern__");
7510 
7511   // If the CUID is not specified we try to generate a unique postfix.
7512   if (getLangOpts().CUID.empty()) {
7513     SourceManager &SM = getContext().getSourceManager();
7514     PresumedLoc PLoc = SM.getPresumedLoc(D->getLocation());
7515     assert(PLoc.isValid() && "Source location is expected to be valid.");
7516 
7517     // Get the hash of the user defined macros.
7518     llvm::MD5 Hash;
7519     llvm::MD5::MD5Result Result;
7520     for (const auto &Arg : PreprocessorOpts.Macros)
7521       Hash.update(Arg.first);
7522     Hash.final(Result);
7523 
7524     // Get the UniqueID for the file containing the decl.
7525     llvm::sys::fs::UniqueID ID;
7526     if (llvm::sys::fs::getUniqueID(PLoc.getFilename(), ID)) {
7527       PLoc = SM.getPresumedLoc(D->getLocation(), /*UseLineDirectives=*/false);
7528       assert(PLoc.isValid() && "Source location is expected to be valid.");
7529       if (auto EC = llvm::sys::fs::getUniqueID(PLoc.getFilename(), ID))
7530         SM.getDiagnostics().Report(diag::err_cannot_open_file)
7531             << PLoc.getFilename() << EC.message();
7532     }
7533     OS << llvm::format("%x", ID.getFile()) << llvm::format("%x", ID.getDevice())
7534        << "_" << llvm::utohexstr(Result.low(), /*LowerCase=*/true, /*Width=*/8);
7535   } else {
7536     OS << getContext().getCUIDHash();
7537   }
7538 }
7539 
7540 void CodeGenModule::moveLazyEmissionStates(CodeGenModule *NewBuilder) {
7541   assert(DeferredDeclsToEmit.empty() &&
7542          "Should have emitted all decls deferred to emit.");
7543   assert(NewBuilder->DeferredDecls.empty() &&
7544          "Newly created module should not have deferred decls");
7545   NewBuilder->DeferredDecls = std::move(DeferredDecls);
7546   assert(EmittedDeferredDecls.empty() &&
7547          "Still have (unmerged) EmittedDeferredDecls deferred decls");
7548 
7549   assert(NewBuilder->DeferredVTables.empty() &&
7550          "Newly created module should not have deferred vtables");
7551   NewBuilder->DeferredVTables = std::move(DeferredVTables);
7552 
7553   assert(NewBuilder->MangledDeclNames.empty() &&
7554          "Newly created module should not have mangled decl names");
7555   assert(NewBuilder->Manglings.empty() &&
7556          "Newly created module should not have manglings");
7557   NewBuilder->Manglings = std::move(Manglings);
7558 
7559   NewBuilder->WeakRefReferences = std::move(WeakRefReferences);
7560 
7561   NewBuilder->TBAA = std::move(TBAA);
7562 
7563   NewBuilder->ABI->MangleCtx = std::move(ABI->MangleCtx);
7564 }
7565