xref: /llvm-project/clang/lib/CodeGen/CodeGenModule.cpp (revision 8d27be8dbaffce0519ac41173d51923fc2524b1b)
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 "CGBlocks.h"
15 #include "CGCUDARuntime.h"
16 #include "CGCXXABI.h"
17 #include "CGCall.h"
18 #include "CGDebugInfo.h"
19 #include "CGObjCRuntime.h"
20 #include "CGOpenCLRuntime.h"
21 #include "CGOpenMPRuntime.h"
22 #include "CGOpenMPRuntimeNVPTX.h"
23 #include "CodeGenFunction.h"
24 #include "CodeGenPGO.h"
25 #include "ConstantEmitter.h"
26 #include "CoverageMappingGen.h"
27 #include "TargetInfo.h"
28 #include "clang/AST/ASTContext.h"
29 #include "clang/AST/CharUnits.h"
30 #include "clang/AST/DeclCXX.h"
31 #include "clang/AST/DeclObjC.h"
32 #include "clang/AST/DeclTemplate.h"
33 #include "clang/AST/Mangle.h"
34 #include "clang/AST/RecordLayout.h"
35 #include "clang/AST/RecursiveASTVisitor.h"
36 #include "clang/AST/StmtVisitor.h"
37 #include "clang/Basic/Builtins.h"
38 #include "clang/Basic/CharInfo.h"
39 #include "clang/Basic/CodeGenOptions.h"
40 #include "clang/Basic/Diagnostic.h"
41 #include "clang/Basic/FileManager.h"
42 #include "clang/Basic/Module.h"
43 #include "clang/Basic/SourceManager.h"
44 #include "clang/Basic/TargetInfo.h"
45 #include "clang/Basic/Version.h"
46 #include "clang/CodeGen/ConstantInitBuilder.h"
47 #include "clang/Frontend/FrontendDiagnostic.h"
48 #include "llvm/ADT/StringSwitch.h"
49 #include "llvm/ADT/Triple.h"
50 #include "llvm/Analysis/TargetLibraryInfo.h"
51 #include "llvm/Frontend/OpenMP/OMPIRBuilder.h"
52 #include "llvm/IR/CallingConv.h"
53 #include "llvm/IR/DataLayout.h"
54 #include "llvm/IR/Intrinsics.h"
55 #include "llvm/IR/LLVMContext.h"
56 #include "llvm/IR/Module.h"
57 #include "llvm/IR/ProfileSummary.h"
58 #include "llvm/ProfileData/InstrProfReader.h"
59 #include "llvm/Support/CodeGen.h"
60 #include "llvm/Support/CommandLine.h"
61 #include "llvm/Support/ConvertUTF.h"
62 #include "llvm/Support/ErrorHandling.h"
63 #include "llvm/Support/MD5.h"
64 #include "llvm/Support/TimeProfiler.h"
65 
66 using namespace clang;
67 using namespace CodeGen;
68 
69 static llvm::cl::opt<bool> LimitedCoverage(
70     "limited-coverage-experimental", llvm::cl::ZeroOrMore, llvm::cl::Hidden,
71     llvm::cl::desc("Emit limited coverage mapping information (experimental)"),
72     llvm::cl::init(false));
73 
74 static const char AnnotationSection[] = "llvm.metadata";
75 
76 static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
77   switch (CGM.getTarget().getCXXABI().getKind()) {
78   case TargetCXXABI::Fuchsia:
79   case TargetCXXABI::GenericAArch64:
80   case TargetCXXABI::GenericARM:
81   case TargetCXXABI::iOS:
82   case TargetCXXABI::iOS64:
83   case TargetCXXABI::WatchOS:
84   case TargetCXXABI::GenericMIPS:
85   case TargetCXXABI::GenericItanium:
86   case TargetCXXABI::WebAssembly:
87   case TargetCXXABI::XL:
88     return CreateItaniumCXXABI(CGM);
89   case TargetCXXABI::Microsoft:
90     return CreateMicrosoftCXXABI(CGM);
91   }
92 
93   llvm_unreachable("invalid C++ ABI kind");
94 }
95 
96 CodeGenModule::CodeGenModule(ASTContext &C, const HeaderSearchOptions &HSO,
97                              const PreprocessorOptions &PPO,
98                              const CodeGenOptions &CGO, llvm::Module &M,
99                              DiagnosticsEngine &diags,
100                              CoverageSourceInfo *CoverageInfo)
101     : Context(C), LangOpts(C.getLangOpts()), HeaderSearchOpts(HSO),
102       PreprocessorOpts(PPO), CodeGenOpts(CGO), TheModule(M), Diags(diags),
103       Target(C.getTargetInfo()), ABI(createCXXABI(*this)),
104       VMContext(M.getContext()), Types(*this), VTables(*this),
105       SanitizerMD(new SanitizerMetadata(*this)) {
106 
107   // Initialize the type cache.
108   llvm::LLVMContext &LLVMContext = M.getContext();
109   VoidTy = llvm::Type::getVoidTy(LLVMContext);
110   Int8Ty = llvm::Type::getInt8Ty(LLVMContext);
111   Int16Ty = llvm::Type::getInt16Ty(LLVMContext);
112   Int32Ty = llvm::Type::getInt32Ty(LLVMContext);
113   Int64Ty = llvm::Type::getInt64Ty(LLVMContext);
114   HalfTy = llvm::Type::getHalfTy(LLVMContext);
115   BFloatTy = llvm::Type::getBFloatTy(LLVMContext);
116   FloatTy = llvm::Type::getFloatTy(LLVMContext);
117   DoubleTy = llvm::Type::getDoubleTy(LLVMContext);
118   PointerWidthInBits = C.getTargetInfo().getPointerWidth(0);
119   PointerAlignInBytes =
120     C.toCharUnitsFromBits(C.getTargetInfo().getPointerAlign(0)).getQuantity();
121   SizeSizeInBytes =
122     C.toCharUnitsFromBits(C.getTargetInfo().getMaxPointerWidth()).getQuantity();
123   IntAlignInBytes =
124     C.toCharUnitsFromBits(C.getTargetInfo().getIntAlign()).getQuantity();
125   IntTy = llvm::IntegerType::get(LLVMContext, C.getTargetInfo().getIntWidth());
126   IntPtrTy = llvm::IntegerType::get(LLVMContext,
127     C.getTargetInfo().getMaxPointerWidth());
128   Int8PtrTy = Int8Ty->getPointerTo(0);
129   Int8PtrPtrTy = Int8PtrTy->getPointerTo(0);
130   AllocaInt8PtrTy = Int8Ty->getPointerTo(
131       M.getDataLayout().getAllocaAddrSpace());
132   ASTAllocaAddressSpace = getTargetCodeGenInfo().getASTAllocaAddressSpace();
133 
134   RuntimeCC = getTargetCodeGenInfo().getABIInfo().getRuntimeCC();
135 
136   if (LangOpts.ObjC)
137     createObjCRuntime();
138   if (LangOpts.OpenCL)
139     createOpenCLRuntime();
140   if (LangOpts.OpenMP)
141     createOpenMPRuntime();
142   if (LangOpts.CUDA)
143     createCUDARuntime();
144 
145   // Enable TBAA unless it's suppressed. ThreadSanitizer needs TBAA even at O0.
146   if (LangOpts.Sanitize.has(SanitizerKind::Thread) ||
147       (!CodeGenOpts.RelaxedAliasing && CodeGenOpts.OptimizationLevel > 0))
148     TBAA.reset(new CodeGenTBAA(Context, TheModule, CodeGenOpts, getLangOpts(),
149                                getCXXABI().getMangleContext()));
150 
151   // If debug info or coverage generation is enabled, create the CGDebugInfo
152   // object.
153   if (CodeGenOpts.getDebugInfo() != codegenoptions::NoDebugInfo ||
154       CodeGenOpts.EmitGcovArcs || CodeGenOpts.EmitGcovNotes)
155     DebugInfo.reset(new CGDebugInfo(*this));
156 
157   Block.GlobalUniqueCount = 0;
158 
159   if (C.getLangOpts().ObjC)
160     ObjCData.reset(new ObjCEntrypoints());
161 
162   if (CodeGenOpts.hasProfileClangUse()) {
163     auto ReaderOrErr = llvm::IndexedInstrProfReader::create(
164         CodeGenOpts.ProfileInstrumentUsePath, CodeGenOpts.ProfileRemappingFile);
165     if (auto E = ReaderOrErr.takeError()) {
166       unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
167                                               "Could not read profile %0: %1");
168       llvm::handleAllErrors(std::move(E), [&](const llvm::ErrorInfoBase &EI) {
169         getDiags().Report(DiagID) << CodeGenOpts.ProfileInstrumentUsePath
170                                   << EI.message();
171       });
172     } else
173       PGOReader = std::move(ReaderOrErr.get());
174   }
175 
176   // If coverage mapping generation is enabled, create the
177   // CoverageMappingModuleGen object.
178   if (CodeGenOpts.CoverageMapping)
179     CoverageMapping.reset(new CoverageMappingModuleGen(*this, *CoverageInfo));
180 }
181 
182 CodeGenModule::~CodeGenModule() {}
183 
184 void CodeGenModule::createObjCRuntime() {
185   // This is just isGNUFamily(), but we want to force implementors of
186   // new ABIs to decide how best to do this.
187   switch (LangOpts.ObjCRuntime.getKind()) {
188   case ObjCRuntime::GNUstep:
189   case ObjCRuntime::GCC:
190   case ObjCRuntime::ObjFW:
191     ObjCRuntime.reset(CreateGNUObjCRuntime(*this));
192     return;
193 
194   case ObjCRuntime::FragileMacOSX:
195   case ObjCRuntime::MacOSX:
196   case ObjCRuntime::iOS:
197   case ObjCRuntime::WatchOS:
198     ObjCRuntime.reset(CreateMacObjCRuntime(*this));
199     return;
200   }
201   llvm_unreachable("bad runtime kind");
202 }
203 
204 void CodeGenModule::createOpenCLRuntime() {
205   OpenCLRuntime.reset(new CGOpenCLRuntime(*this));
206 }
207 
208 void CodeGenModule::createOpenMPRuntime() {
209   // Select a specialized code generation class based on the target, if any.
210   // If it does not exist use the default implementation.
211   switch (getTriple().getArch()) {
212   case llvm::Triple::nvptx:
213   case llvm::Triple::nvptx64:
214     assert(getLangOpts().OpenMPIsDevice &&
215            "OpenMP NVPTX is only prepared to deal with device code.");
216     OpenMPRuntime.reset(new CGOpenMPRuntimeNVPTX(*this));
217     break;
218   default:
219     if (LangOpts.OpenMPSimd)
220       OpenMPRuntime.reset(new CGOpenMPSIMDRuntime(*this));
221     else
222       OpenMPRuntime.reset(new CGOpenMPRuntime(*this));
223     break;
224   }
225 }
226 
227 void CodeGenModule::createCUDARuntime() {
228   CUDARuntime.reset(CreateNVCUDARuntime(*this));
229 }
230 
231 void CodeGenModule::addReplacement(StringRef Name, llvm::Constant *C) {
232   Replacements[Name] = C;
233 }
234 
235 void CodeGenModule::applyReplacements() {
236   for (auto &I : Replacements) {
237     StringRef MangledName = I.first();
238     llvm::Constant *Replacement = I.second;
239     llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
240     if (!Entry)
241       continue;
242     auto *OldF = cast<llvm::Function>(Entry);
243     auto *NewF = dyn_cast<llvm::Function>(Replacement);
244     if (!NewF) {
245       if (auto *Alias = dyn_cast<llvm::GlobalAlias>(Replacement)) {
246         NewF = dyn_cast<llvm::Function>(Alias->getAliasee());
247       } else {
248         auto *CE = cast<llvm::ConstantExpr>(Replacement);
249         assert(CE->getOpcode() == llvm::Instruction::BitCast ||
250                CE->getOpcode() == llvm::Instruction::GetElementPtr);
251         NewF = dyn_cast<llvm::Function>(CE->getOperand(0));
252       }
253     }
254 
255     // Replace old with new, but keep the old order.
256     OldF->replaceAllUsesWith(Replacement);
257     if (NewF) {
258       NewF->removeFromParent();
259       OldF->getParent()->getFunctionList().insertAfter(OldF->getIterator(),
260                                                        NewF);
261     }
262     OldF->eraseFromParent();
263   }
264 }
265 
266 void CodeGenModule::addGlobalValReplacement(llvm::GlobalValue *GV, llvm::Constant *C) {
267   GlobalValReplacements.push_back(std::make_pair(GV, C));
268 }
269 
270 void CodeGenModule::applyGlobalValReplacements() {
271   for (auto &I : GlobalValReplacements) {
272     llvm::GlobalValue *GV = I.first;
273     llvm::Constant *C = I.second;
274 
275     GV->replaceAllUsesWith(C);
276     GV->eraseFromParent();
277   }
278 }
279 
280 // This is only used in aliases that we created and we know they have a
281 // linear structure.
282 static const llvm::GlobalObject *getAliasedGlobal(
283     const llvm::GlobalIndirectSymbol &GIS) {
284   llvm::SmallPtrSet<const llvm::GlobalIndirectSymbol*, 4> Visited;
285   const llvm::Constant *C = &GIS;
286   for (;;) {
287     C = C->stripPointerCasts();
288     if (auto *GO = dyn_cast<llvm::GlobalObject>(C))
289       return GO;
290     // stripPointerCasts will not walk over weak aliases.
291     auto *GIS2 = dyn_cast<llvm::GlobalIndirectSymbol>(C);
292     if (!GIS2)
293       return nullptr;
294     if (!Visited.insert(GIS2).second)
295       return nullptr;
296     C = GIS2->getIndirectSymbol();
297   }
298 }
299 
300 void CodeGenModule::checkAliases() {
301   // Check if the constructed aliases are well formed. It is really unfortunate
302   // that we have to do this in CodeGen, but we only construct mangled names
303   // and aliases during codegen.
304   bool Error = false;
305   DiagnosticsEngine &Diags = getDiags();
306   for (const GlobalDecl &GD : Aliases) {
307     const auto *D = cast<ValueDecl>(GD.getDecl());
308     SourceLocation Location;
309     bool IsIFunc = D->hasAttr<IFuncAttr>();
310     if (const Attr *A = D->getDefiningAttr())
311       Location = A->getLocation();
312     else
313       llvm_unreachable("Not an alias or ifunc?");
314     StringRef MangledName = getMangledName(GD);
315     llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
316     auto *Alias  = cast<llvm::GlobalIndirectSymbol>(Entry);
317     const llvm::GlobalValue *GV = getAliasedGlobal(*Alias);
318     if (!GV) {
319       Error = true;
320       Diags.Report(Location, diag::err_cyclic_alias) << IsIFunc;
321     } else if (GV->isDeclaration()) {
322       Error = true;
323       Diags.Report(Location, diag::err_alias_to_undefined)
324           << IsIFunc << IsIFunc;
325     } else if (IsIFunc) {
326       // Check resolver function type.
327       llvm::FunctionType *FTy = dyn_cast<llvm::FunctionType>(
328           GV->getType()->getPointerElementType());
329       assert(FTy);
330       if (!FTy->getReturnType()->isPointerTy())
331         Diags.Report(Location, diag::err_ifunc_resolver_return);
332     }
333 
334     llvm::Constant *Aliasee = Alias->getIndirectSymbol();
335     llvm::GlobalValue *AliaseeGV;
336     if (auto CE = dyn_cast<llvm::ConstantExpr>(Aliasee))
337       AliaseeGV = cast<llvm::GlobalValue>(CE->getOperand(0));
338     else
339       AliaseeGV = cast<llvm::GlobalValue>(Aliasee);
340 
341     if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
342       StringRef AliasSection = SA->getName();
343       if (AliasSection != AliaseeGV->getSection())
344         Diags.Report(SA->getLocation(), diag::warn_alias_with_section)
345             << AliasSection << IsIFunc << IsIFunc;
346     }
347 
348     // We have to handle alias to weak aliases in here. LLVM itself disallows
349     // this since the object semantics would not match the IL one. For
350     // compatibility with gcc we implement it by just pointing the alias
351     // to its aliasee's aliasee. We also warn, since the user is probably
352     // expecting the link to be weak.
353     if (auto GA = dyn_cast<llvm::GlobalIndirectSymbol>(AliaseeGV)) {
354       if (GA->isInterposable()) {
355         Diags.Report(Location, diag::warn_alias_to_weak_alias)
356             << GV->getName() << GA->getName() << IsIFunc;
357         Aliasee = llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
358             GA->getIndirectSymbol(), Alias->getType());
359         Alias->setIndirectSymbol(Aliasee);
360       }
361     }
362   }
363   if (!Error)
364     return;
365 
366   for (const GlobalDecl &GD : Aliases) {
367     StringRef MangledName = getMangledName(GD);
368     llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
369     auto *Alias = dyn_cast<llvm::GlobalIndirectSymbol>(Entry);
370     Alias->replaceAllUsesWith(llvm::UndefValue::get(Alias->getType()));
371     Alias->eraseFromParent();
372   }
373 }
374 
375 void CodeGenModule::clear() {
376   DeferredDeclsToEmit.clear();
377   if (OpenMPRuntime)
378     OpenMPRuntime->clear();
379 }
380 
381 void InstrProfStats::reportDiagnostics(DiagnosticsEngine &Diags,
382                                        StringRef MainFile) {
383   if (!hasDiagnostics())
384     return;
385   if (VisitedInMainFile > 0 && VisitedInMainFile == MissingInMainFile) {
386     if (MainFile.empty())
387       MainFile = "<stdin>";
388     Diags.Report(diag::warn_profile_data_unprofiled) << MainFile;
389   } else {
390     if (Mismatched > 0)
391       Diags.Report(diag::warn_profile_data_out_of_date) << Visited << Mismatched;
392 
393     if (Missing > 0)
394       Diags.Report(diag::warn_profile_data_missing) << Visited << Missing;
395   }
396 }
397 
398 void CodeGenModule::Release() {
399   EmitDeferred();
400   EmitVTablesOpportunistically();
401   applyGlobalValReplacements();
402   applyReplacements();
403   checkAliases();
404   emitMultiVersionFunctions();
405   EmitCXXGlobalInitFunc();
406   EmitCXXGlobalCleanUpFunc();
407   registerGlobalDtorsWithAtExit();
408   EmitCXXThreadLocalInitFunc();
409   if (ObjCRuntime)
410     if (llvm::Function *ObjCInitFunction = ObjCRuntime->ModuleInitFunction())
411       AddGlobalCtor(ObjCInitFunction);
412   if (Context.getLangOpts().CUDA && !Context.getLangOpts().CUDAIsDevice &&
413       CUDARuntime) {
414     if (llvm::Function *CudaCtorFunction =
415             CUDARuntime->makeModuleCtorFunction())
416       AddGlobalCtor(CudaCtorFunction);
417   }
418   if (OpenMPRuntime) {
419     if (llvm::Function *OpenMPRequiresDirectiveRegFun =
420             OpenMPRuntime->emitRequiresDirectiveRegFun()) {
421       AddGlobalCtor(OpenMPRequiresDirectiveRegFun, 0);
422     }
423     OpenMPRuntime->createOffloadEntriesAndInfoMetadata();
424     OpenMPRuntime->clear();
425   }
426   if (PGOReader) {
427     getModule().setProfileSummary(
428         PGOReader->getSummary(/* UseCS */ false).getMD(VMContext),
429         llvm::ProfileSummary::PSK_Instr);
430     if (PGOStats.hasDiagnostics())
431       PGOStats.reportDiagnostics(getDiags(), getCodeGenOpts().MainFileName);
432   }
433   EmitCtorList(GlobalCtors, "llvm.global_ctors");
434   EmitCtorList(GlobalDtors, "llvm.global_dtors");
435   EmitGlobalAnnotations();
436   EmitStaticExternCAliases();
437   EmitDeferredUnusedCoverageMappings();
438   if (CoverageMapping)
439     CoverageMapping->emit();
440   if (CodeGenOpts.SanitizeCfiCrossDso) {
441     CodeGenFunction(*this).EmitCfiCheckFail();
442     CodeGenFunction(*this).EmitCfiCheckStub();
443   }
444   emitAtAvailableLinkGuard();
445   if (Context.getTargetInfo().getTriple().isWasm() &&
446       !Context.getTargetInfo().getTriple().isOSEmscripten()) {
447     EmitMainVoidAlias();
448   }
449   emitLLVMUsed();
450   if (SanStats)
451     SanStats->finish();
452 
453   if (CodeGenOpts.Autolink &&
454       (Context.getLangOpts().Modules || !LinkerOptionsMetadata.empty())) {
455     EmitModuleLinkOptions();
456   }
457 
458   // On ELF we pass the dependent library specifiers directly to the linker
459   // without manipulating them. This is in contrast to other platforms where
460   // they are mapped to a specific linker option by the compiler. This
461   // difference is a result of the greater variety of ELF linkers and the fact
462   // that ELF linkers tend to handle libraries in a more complicated fashion
463   // than on other platforms. This forces us to defer handling the dependent
464   // libs to the linker.
465   //
466   // CUDA/HIP device and host libraries are different. Currently there is no
467   // way to differentiate dependent libraries for host or device. Existing
468   // usage of #pragma comment(lib, *) is intended for host libraries on
469   // Windows. Therefore emit llvm.dependent-libraries only for host.
470   if (!ELFDependentLibraries.empty() && !Context.getLangOpts().CUDAIsDevice) {
471     auto *NMD = getModule().getOrInsertNamedMetadata("llvm.dependent-libraries");
472     for (auto *MD : ELFDependentLibraries)
473       NMD->addOperand(MD);
474   }
475 
476   // Record mregparm value now so it is visible through rest of codegen.
477   if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
478     getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
479                               CodeGenOpts.NumRegisterParameters);
480 
481   if (CodeGenOpts.DwarfVersion) {
482     getModule().addModuleFlag(llvm::Module::Max, "Dwarf Version",
483                               CodeGenOpts.DwarfVersion);
484   }
485 
486   if (Context.getLangOpts().SemanticInterposition)
487     // Require various optimization to respect semantic interposition.
488     getModule().setSemanticInterposition(1);
489   else if (Context.getLangOpts().ExplicitNoSemanticInterposition)
490     // Allow dso_local on applicable targets.
491     getModule().setSemanticInterposition(0);
492 
493   if (CodeGenOpts.EmitCodeView) {
494     // Indicate that we want CodeView in the metadata.
495     getModule().addModuleFlag(llvm::Module::Warning, "CodeView", 1);
496   }
497   if (CodeGenOpts.CodeViewGHash) {
498     getModule().addModuleFlag(llvm::Module::Warning, "CodeViewGHash", 1);
499   }
500   if (CodeGenOpts.ControlFlowGuard) {
501     // Function ID tables and checks for Control Flow Guard (cfguard=2).
502     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 2);
503   } else if (CodeGenOpts.ControlFlowGuardNoChecks) {
504     // Function ID tables for Control Flow Guard (cfguard=1).
505     getModule().addModuleFlag(llvm::Module::Warning, "cfguard", 1);
506   }
507   if (CodeGenOpts.OptimizationLevel > 0 && CodeGenOpts.StrictVTablePointers) {
508     // We don't support LTO with 2 with different StrictVTablePointers
509     // FIXME: we could support it by stripping all the information introduced
510     // by StrictVTablePointers.
511 
512     getModule().addModuleFlag(llvm::Module::Error, "StrictVTablePointers",1);
513 
514     llvm::Metadata *Ops[2] = {
515               llvm::MDString::get(VMContext, "StrictVTablePointers"),
516               llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
517                   llvm::Type::getInt32Ty(VMContext), 1))};
518 
519     getModule().addModuleFlag(llvm::Module::Require,
520                               "StrictVTablePointersRequirement",
521                               llvm::MDNode::get(VMContext, Ops));
522   }
523   if (getModuleDebugInfo())
524     // We support a single version in the linked module. The LLVM
525     // parser will drop debug info with a different version number
526     // (and warn about it, too).
527     getModule().addModuleFlag(llvm::Module::Warning, "Debug Info Version",
528                               llvm::DEBUG_METADATA_VERSION);
529 
530   // We need to record the widths of enums and wchar_t, so that we can generate
531   // the correct build attributes in the ARM backend. wchar_size is also used by
532   // TargetLibraryInfo.
533   uint64_t WCharWidth =
534       Context.getTypeSizeInChars(Context.getWideCharType()).getQuantity();
535   getModule().addModuleFlag(llvm::Module::Error, "wchar_size", WCharWidth);
536 
537   llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch();
538   if (   Arch == llvm::Triple::arm
539       || Arch == llvm::Triple::armeb
540       || Arch == llvm::Triple::thumb
541       || Arch == llvm::Triple::thumbeb) {
542     // The minimum width of an enum in bytes
543     uint64_t EnumWidth = Context.getLangOpts().ShortEnums ? 1 : 4;
544     getModule().addModuleFlag(llvm::Module::Error, "min_enum_size", EnumWidth);
545   }
546 
547   if (Arch == llvm::Triple::riscv32 || Arch == llvm::Triple::riscv64) {
548     StringRef ABIStr = Target.getABI();
549     llvm::LLVMContext &Ctx = TheModule.getContext();
550     getModule().addModuleFlag(llvm::Module::Error, "target-abi",
551                               llvm::MDString::get(Ctx, ABIStr));
552   }
553 
554   if (CodeGenOpts.SanitizeCfiCrossDso) {
555     // Indicate that we want cross-DSO control flow integrity checks.
556     getModule().addModuleFlag(llvm::Module::Override, "Cross-DSO CFI", 1);
557   }
558 
559   if (CodeGenOpts.WholeProgramVTables) {
560     // Indicate whether VFE was enabled for this module, so that the
561     // vcall_visibility metadata added under whole program vtables is handled
562     // appropriately in the optimizer.
563     getModule().addModuleFlag(llvm::Module::Error, "Virtual Function Elim",
564                               CodeGenOpts.VirtualFunctionElimination);
565   }
566 
567   if (LangOpts.Sanitize.has(SanitizerKind::CFIICall)) {
568     getModule().addModuleFlag(llvm::Module::Override,
569                               "CFI Canonical Jump Tables",
570                               CodeGenOpts.SanitizeCfiCanonicalJumpTables);
571   }
572 
573   if (CodeGenOpts.CFProtectionReturn &&
574       Target.checkCFProtectionReturnSupported(getDiags())) {
575     // Indicate that we want to instrument return control flow protection.
576     getModule().addModuleFlag(llvm::Module::Override, "cf-protection-return",
577                               1);
578   }
579 
580   if (CodeGenOpts.CFProtectionBranch &&
581       Target.checkCFProtectionBranchSupported(getDiags())) {
582     // Indicate that we want to instrument branch control flow protection.
583     getModule().addModuleFlag(llvm::Module::Override, "cf-protection-branch",
584                               1);
585   }
586 
587   if (LangOpts.CUDAIsDevice && getTriple().isNVPTX()) {
588     // Indicate whether __nvvm_reflect should be configured to flush denormal
589     // floating point values to 0.  (This corresponds to its "__CUDA_FTZ"
590     // property.)
591     getModule().addModuleFlag(llvm::Module::Override, "nvvm-reflect-ftz",
592                               CodeGenOpts.FP32DenormalMode.Output !=
593                                   llvm::DenormalMode::IEEE);
594   }
595 
596   // Emit OpenCL specific module metadata: OpenCL/SPIR version.
597   if (LangOpts.OpenCL) {
598     EmitOpenCLMetadata();
599     // Emit SPIR version.
600     if (getTriple().isSPIR()) {
601       // SPIR v2.0 s2.12 - The SPIR version used by the module is stored in the
602       // opencl.spir.version named metadata.
603       // C++ is backwards compatible with OpenCL v2.0.
604       auto Version = LangOpts.OpenCLCPlusPlus ? 200 : LangOpts.OpenCLVersion;
605       llvm::Metadata *SPIRVerElts[] = {
606           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
607               Int32Ty, Version / 100)),
608           llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
609               Int32Ty, (Version / 100 > 1) ? 0 : 2))};
610       llvm::NamedMDNode *SPIRVerMD =
611           TheModule.getOrInsertNamedMetadata("opencl.spir.version");
612       llvm::LLVMContext &Ctx = TheModule.getContext();
613       SPIRVerMD->addOperand(llvm::MDNode::get(Ctx, SPIRVerElts));
614     }
615   }
616 
617   if (uint32_t PLevel = Context.getLangOpts().PICLevel) {
618     assert(PLevel < 3 && "Invalid PIC Level");
619     getModule().setPICLevel(static_cast<llvm::PICLevel::Level>(PLevel));
620     if (Context.getLangOpts().PIE)
621       getModule().setPIELevel(static_cast<llvm::PIELevel::Level>(PLevel));
622   }
623 
624   if (getCodeGenOpts().CodeModel.size() > 0) {
625     unsigned CM = llvm::StringSwitch<unsigned>(getCodeGenOpts().CodeModel)
626                   .Case("tiny", llvm::CodeModel::Tiny)
627                   .Case("small", llvm::CodeModel::Small)
628                   .Case("kernel", llvm::CodeModel::Kernel)
629                   .Case("medium", llvm::CodeModel::Medium)
630                   .Case("large", llvm::CodeModel::Large)
631                   .Default(~0u);
632     if (CM != ~0u) {
633       llvm::CodeModel::Model codeModel = static_cast<llvm::CodeModel::Model>(CM);
634       getModule().setCodeModel(codeModel);
635     }
636   }
637 
638   if (CodeGenOpts.NoPLT)
639     getModule().setRtLibUseGOT();
640 
641   SimplifyPersonality();
642 
643   if (getCodeGenOpts().EmitDeclMetadata)
644     EmitDeclMetadata();
645 
646   if (getCodeGenOpts().EmitGcovArcs || getCodeGenOpts().EmitGcovNotes)
647     EmitCoverageFile();
648 
649   if (CGDebugInfo *DI = getModuleDebugInfo())
650     DI->finalize();
651 
652   if (getCodeGenOpts().EmitVersionIdentMetadata)
653     EmitVersionIdentMetadata();
654 
655   if (!getCodeGenOpts().RecordCommandLine.empty())
656     EmitCommandLineMetadata();
657 
658   getTargetCodeGenInfo().emitTargetMetadata(*this, MangledDeclNames);
659 
660   EmitBackendOptionsMetadata(getCodeGenOpts());
661 }
662 
663 void CodeGenModule::EmitOpenCLMetadata() {
664   // SPIR v2.0 s2.13 - The OpenCL version used by the module is stored in the
665   // opencl.ocl.version named metadata node.
666   // C++ is backwards compatible with OpenCL v2.0.
667   // FIXME: We might need to add CXX version at some point too?
668   auto Version = LangOpts.OpenCLCPlusPlus ? 200 : LangOpts.OpenCLVersion;
669   llvm::Metadata *OCLVerElts[] = {
670       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
671           Int32Ty, Version / 100)),
672       llvm::ConstantAsMetadata::get(llvm::ConstantInt::get(
673           Int32Ty, (Version % 100) / 10))};
674   llvm::NamedMDNode *OCLVerMD =
675       TheModule.getOrInsertNamedMetadata("opencl.ocl.version");
676   llvm::LLVMContext &Ctx = TheModule.getContext();
677   OCLVerMD->addOperand(llvm::MDNode::get(Ctx, OCLVerElts));
678 }
679 
680 void CodeGenModule::EmitBackendOptionsMetadata(
681     const CodeGenOptions CodeGenOpts) {
682   switch (getTriple().getArch()) {
683   default:
684     break;
685   case llvm::Triple::riscv32:
686   case llvm::Triple::riscv64:
687     getModule().addModuleFlag(llvm::Module::Error, "SmallDataLimit",
688                               CodeGenOpts.SmallDataLimit);
689     break;
690   }
691 }
692 
693 void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
694   // Make sure that this type is translated.
695   Types.UpdateCompletedType(TD);
696 }
697 
698 void CodeGenModule::RefreshTypeCacheForClass(const CXXRecordDecl *RD) {
699   // Make sure that this type is translated.
700   Types.RefreshTypeCacheForClass(RD);
701 }
702 
703 llvm::MDNode *CodeGenModule::getTBAATypeInfo(QualType QTy) {
704   if (!TBAA)
705     return nullptr;
706   return TBAA->getTypeInfo(QTy);
707 }
708 
709 TBAAAccessInfo CodeGenModule::getTBAAAccessInfo(QualType AccessType) {
710   if (!TBAA)
711     return TBAAAccessInfo();
712   if (getLangOpts().CUDAIsDevice) {
713     // As CUDA builtin surface/texture types are replaced, skip generating TBAA
714     // access info.
715     if (AccessType->isCUDADeviceBuiltinSurfaceType()) {
716       if (getTargetCodeGenInfo().getCUDADeviceBuiltinSurfaceDeviceType() !=
717           nullptr)
718         return TBAAAccessInfo();
719     } else if (AccessType->isCUDADeviceBuiltinTextureType()) {
720       if (getTargetCodeGenInfo().getCUDADeviceBuiltinTextureDeviceType() !=
721           nullptr)
722         return TBAAAccessInfo();
723     }
724   }
725   return TBAA->getAccessInfo(AccessType);
726 }
727 
728 TBAAAccessInfo
729 CodeGenModule::getTBAAVTablePtrAccessInfo(llvm::Type *VTablePtrType) {
730   if (!TBAA)
731     return TBAAAccessInfo();
732   return TBAA->getVTablePtrAccessInfo(VTablePtrType);
733 }
734 
735 llvm::MDNode *CodeGenModule::getTBAAStructInfo(QualType QTy) {
736   if (!TBAA)
737     return nullptr;
738   return TBAA->getTBAAStructInfo(QTy);
739 }
740 
741 llvm::MDNode *CodeGenModule::getTBAABaseTypeInfo(QualType QTy) {
742   if (!TBAA)
743     return nullptr;
744   return TBAA->getBaseTypeInfo(QTy);
745 }
746 
747 llvm::MDNode *CodeGenModule::getTBAAAccessTagInfo(TBAAAccessInfo Info) {
748   if (!TBAA)
749     return nullptr;
750   return TBAA->getAccessTagInfo(Info);
751 }
752 
753 TBAAAccessInfo CodeGenModule::mergeTBAAInfoForCast(TBAAAccessInfo SourceInfo,
754                                                    TBAAAccessInfo TargetInfo) {
755   if (!TBAA)
756     return TBAAAccessInfo();
757   return TBAA->mergeTBAAInfoForCast(SourceInfo, TargetInfo);
758 }
759 
760 TBAAAccessInfo
761 CodeGenModule::mergeTBAAInfoForConditionalOperator(TBAAAccessInfo InfoA,
762                                                    TBAAAccessInfo InfoB) {
763   if (!TBAA)
764     return TBAAAccessInfo();
765   return TBAA->mergeTBAAInfoForConditionalOperator(InfoA, InfoB);
766 }
767 
768 TBAAAccessInfo
769 CodeGenModule::mergeTBAAInfoForMemoryTransfer(TBAAAccessInfo DestInfo,
770                                               TBAAAccessInfo SrcInfo) {
771   if (!TBAA)
772     return TBAAAccessInfo();
773   return TBAA->mergeTBAAInfoForConditionalOperator(DestInfo, SrcInfo);
774 }
775 
776 void CodeGenModule::DecorateInstructionWithTBAA(llvm::Instruction *Inst,
777                                                 TBAAAccessInfo TBAAInfo) {
778   if (llvm::MDNode *Tag = getTBAAAccessTagInfo(TBAAInfo))
779     Inst->setMetadata(llvm::LLVMContext::MD_tbaa, Tag);
780 }
781 
782 void CodeGenModule::DecorateInstructionWithInvariantGroup(
783     llvm::Instruction *I, const CXXRecordDecl *RD) {
784   I->setMetadata(llvm::LLVMContext::MD_invariant_group,
785                  llvm::MDNode::get(getLLVMContext(), {}));
786 }
787 
788 void CodeGenModule::Error(SourceLocation loc, StringRef message) {
789   unsigned diagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error, "%0");
790   getDiags().Report(Context.getFullLoc(loc), diagID) << message;
791 }
792 
793 /// ErrorUnsupported - Print out an error that codegen doesn't support the
794 /// specified stmt yet.
795 void CodeGenModule::ErrorUnsupported(const Stmt *S, const char *Type) {
796   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
797                                                "cannot compile this %0 yet");
798   std::string Msg = Type;
799   getDiags().Report(Context.getFullLoc(S->getBeginLoc()), DiagID)
800       << Msg << S->getSourceRange();
801 }
802 
803 /// ErrorUnsupported - Print out an error that codegen doesn't support the
804 /// specified decl yet.
805 void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type) {
806   unsigned DiagID = getDiags().getCustomDiagID(DiagnosticsEngine::Error,
807                                                "cannot compile this %0 yet");
808   std::string Msg = Type;
809   getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
810 }
811 
812 llvm::ConstantInt *CodeGenModule::getSize(CharUnits size) {
813   return llvm::ConstantInt::get(SizeTy, size.getQuantity());
814 }
815 
816 void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV,
817                                         const NamedDecl *D) const {
818   if (GV->hasDLLImportStorageClass())
819     return;
820   // Internal definitions always have default visibility.
821   if (GV->hasLocalLinkage()) {
822     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
823     return;
824   }
825   if (!D)
826     return;
827   // Set visibility for definitions, and for declarations if requested globally
828   // or set explicitly.
829   LinkageInfo LV = D->getLinkageAndVisibility();
830   if (LV.isVisibilityExplicit() || getLangOpts().SetVisibilityForExternDecls ||
831       !GV->isDeclarationForLinker())
832     GV->setVisibility(GetLLVMVisibility(LV.getVisibility()));
833 }
834 
835 static bool shouldAssumeDSOLocal(const CodeGenModule &CGM,
836                                  llvm::GlobalValue *GV) {
837   if (GV->hasLocalLinkage())
838     return true;
839 
840   if (!GV->hasDefaultVisibility() && !GV->hasExternalWeakLinkage())
841     return true;
842 
843   // DLLImport explicitly marks the GV as external.
844   if (GV->hasDLLImportStorageClass())
845     return false;
846 
847   const llvm::Triple &TT = CGM.getTriple();
848   if (TT.isWindowsGNUEnvironment()) {
849     // In MinGW, variables without DLLImport can still be automatically
850     // imported from a DLL by the linker; don't mark variables that
851     // potentially could come from another DLL as DSO local.
852     if (GV->isDeclarationForLinker() && isa<llvm::GlobalVariable>(GV) &&
853         !GV->isThreadLocal())
854       return false;
855   }
856 
857   // On COFF, don't mark 'extern_weak' symbols as DSO local. If these symbols
858   // remain unresolved in the link, they can be resolved to zero, which is
859   // outside the current DSO.
860   if (TT.isOSBinFormatCOFF() && GV->hasExternalWeakLinkage())
861     return false;
862 
863   // Every other GV is local on COFF.
864   // Make an exception for windows OS in the triple: Some firmware builds use
865   // *-win32-macho triples. This (accidentally?) produced windows relocations
866   // without GOT tables in older clang versions; Keep this behaviour.
867   // FIXME: even thread local variables?
868   if (TT.isOSBinFormatCOFF() || (TT.isOSWindows() && TT.isOSBinFormatMachO()))
869     return true;
870 
871   // Only handle COFF and ELF for now.
872   if (!TT.isOSBinFormatELF())
873     return false;
874 
875   // If this is not an executable, don't assume anything is local.
876   const auto &CGOpts = CGM.getCodeGenOpts();
877   llvm::Reloc::Model RM = CGOpts.RelocationModel;
878   const auto &LOpts = CGM.getLangOpts();
879   if (RM != llvm::Reloc::Static && !LOpts.PIE)
880     return false;
881 
882   // A definition cannot be preempted from an executable.
883   if (!GV->isDeclarationForLinker())
884     return true;
885 
886   // Most PIC code sequences that assume that a symbol is local cannot produce a
887   // 0 if it turns out the symbol is undefined. While this is ABI and relocation
888   // depended, it seems worth it to handle it here.
889   if (RM == llvm::Reloc::PIC_ && GV->hasExternalWeakLinkage())
890     return false;
891 
892   // PPC has no copy relocations and cannot use a plt entry as a symbol address.
893   llvm::Triple::ArchType Arch = TT.getArch();
894   if (Arch == llvm::Triple::ppc || Arch == llvm::Triple::ppc64 ||
895       Arch == llvm::Triple::ppc64le)
896     return false;
897 
898   // If we can use copy relocations we can assume it is local.
899   if (auto *Var = dyn_cast<llvm::GlobalVariable>(GV))
900     if (!Var->isThreadLocal() &&
901         (RM == llvm::Reloc::Static || CGOpts.PIECopyRelocations))
902       return true;
903 
904   // If we can use a plt entry as the symbol address we can assume it
905   // is local.
906   // FIXME: This should work for PIE, but the gold linker doesn't support it.
907   if (isa<llvm::Function>(GV) && !CGOpts.NoPLT && RM == llvm::Reloc::Static)
908     return true;
909 
910   // Otherwise don't assume it is local.
911   return false;
912 }
913 
914 void CodeGenModule::setDSOLocal(llvm::GlobalValue *GV) const {
915   GV->setDSOLocal(shouldAssumeDSOLocal(*this, GV));
916 }
917 
918 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
919                                           GlobalDecl GD) const {
920   const auto *D = dyn_cast<NamedDecl>(GD.getDecl());
921   // C++ destructors have a few C++ ABI specific special cases.
922   if (const auto *Dtor = dyn_cast_or_null<CXXDestructorDecl>(D)) {
923     getCXXABI().setCXXDestructorDLLStorage(GV, Dtor, GD.getDtorType());
924     return;
925   }
926   setDLLImportDLLExport(GV, D);
927 }
928 
929 void CodeGenModule::setDLLImportDLLExport(llvm::GlobalValue *GV,
930                                           const NamedDecl *D) const {
931   if (D && D->isExternallyVisible()) {
932     if (D->hasAttr<DLLImportAttr>())
933       GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
934     else if (D->hasAttr<DLLExportAttr>() && !GV->isDeclarationForLinker())
935       GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
936   }
937 }
938 
939 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
940                                     GlobalDecl GD) const {
941   setDLLImportDLLExport(GV, GD);
942   setGVPropertiesAux(GV, dyn_cast<NamedDecl>(GD.getDecl()));
943 }
944 
945 void CodeGenModule::setGVProperties(llvm::GlobalValue *GV,
946                                     const NamedDecl *D) const {
947   setDLLImportDLLExport(GV, D);
948   setGVPropertiesAux(GV, D);
949 }
950 
951 void CodeGenModule::setGVPropertiesAux(llvm::GlobalValue *GV,
952                                        const NamedDecl *D) const {
953   setGlobalVisibility(GV, D);
954   setDSOLocal(GV);
955   GV->setPartition(CodeGenOpts.SymbolPartition);
956 }
957 
958 static llvm::GlobalVariable::ThreadLocalMode GetLLVMTLSModel(StringRef S) {
959   return llvm::StringSwitch<llvm::GlobalVariable::ThreadLocalMode>(S)
960       .Case("global-dynamic", llvm::GlobalVariable::GeneralDynamicTLSModel)
961       .Case("local-dynamic", llvm::GlobalVariable::LocalDynamicTLSModel)
962       .Case("initial-exec", llvm::GlobalVariable::InitialExecTLSModel)
963       .Case("local-exec", llvm::GlobalVariable::LocalExecTLSModel);
964 }
965 
966 llvm::GlobalVariable::ThreadLocalMode
967 CodeGenModule::GetDefaultLLVMTLSModel() const {
968   switch (CodeGenOpts.getDefaultTLSModel()) {
969   case CodeGenOptions::GeneralDynamicTLSModel:
970     return llvm::GlobalVariable::GeneralDynamicTLSModel;
971   case CodeGenOptions::LocalDynamicTLSModel:
972     return llvm::GlobalVariable::LocalDynamicTLSModel;
973   case CodeGenOptions::InitialExecTLSModel:
974     return llvm::GlobalVariable::InitialExecTLSModel;
975   case CodeGenOptions::LocalExecTLSModel:
976     return llvm::GlobalVariable::LocalExecTLSModel;
977   }
978   llvm_unreachable("Invalid TLS model!");
979 }
980 
981 void CodeGenModule::setTLSMode(llvm::GlobalValue *GV, const VarDecl &D) const {
982   assert(D.getTLSKind() && "setting TLS mode on non-TLS var!");
983 
984   llvm::GlobalValue::ThreadLocalMode TLM;
985   TLM = GetDefaultLLVMTLSModel();
986 
987   // Override the TLS model if it is explicitly specified.
988   if (const TLSModelAttr *Attr = D.getAttr<TLSModelAttr>()) {
989     TLM = GetLLVMTLSModel(Attr->getModel());
990   }
991 
992   GV->setThreadLocalMode(TLM);
993 }
994 
995 static std::string getCPUSpecificMangling(const CodeGenModule &CGM,
996                                           StringRef Name) {
997   const TargetInfo &Target = CGM.getTarget();
998   return (Twine('.') + Twine(Target.CPUSpecificManglingCharacter(Name))).str();
999 }
1000 
1001 static void AppendCPUSpecificCPUDispatchMangling(const CodeGenModule &CGM,
1002                                                  const CPUSpecificAttr *Attr,
1003                                                  unsigned CPUIndex,
1004                                                  raw_ostream &Out) {
1005   // cpu_specific gets the current name, dispatch gets the resolver if IFunc is
1006   // supported.
1007   if (Attr)
1008     Out << getCPUSpecificMangling(CGM, Attr->getCPUName(CPUIndex)->getName());
1009   else if (CGM.getTarget().supportsIFunc())
1010     Out << ".resolver";
1011 }
1012 
1013 static void AppendTargetMangling(const CodeGenModule &CGM,
1014                                  const TargetAttr *Attr, raw_ostream &Out) {
1015   if (Attr->isDefaultVersion())
1016     return;
1017 
1018   Out << '.';
1019   const TargetInfo &Target = CGM.getTarget();
1020   ParsedTargetAttr Info =
1021       Attr->parse([&Target](StringRef LHS, StringRef RHS) {
1022         // Multiversioning doesn't allow "no-${feature}", so we can
1023         // only have "+" prefixes here.
1024         assert(LHS.startswith("+") && RHS.startswith("+") &&
1025                "Features should always have a prefix.");
1026         return Target.multiVersionSortPriority(LHS.substr(1)) >
1027                Target.multiVersionSortPriority(RHS.substr(1));
1028       });
1029 
1030   bool IsFirst = true;
1031 
1032   if (!Info.Architecture.empty()) {
1033     IsFirst = false;
1034     Out << "arch_" << Info.Architecture;
1035   }
1036 
1037   for (StringRef Feat : Info.Features) {
1038     if (!IsFirst)
1039       Out << '_';
1040     IsFirst = false;
1041     Out << Feat.substr(1);
1042   }
1043 }
1044 
1045 static std::string getMangledNameImpl(const CodeGenModule &CGM, GlobalDecl GD,
1046                                       const NamedDecl *ND,
1047                                       bool OmitMultiVersionMangling = false) {
1048   SmallString<256> Buffer;
1049   llvm::raw_svector_ostream Out(Buffer);
1050   MangleContext &MC = CGM.getCXXABI().getMangleContext();
1051   if (MC.shouldMangleDeclName(ND))
1052     MC.mangleName(GD.getWithDecl(ND), Out);
1053   else {
1054     IdentifierInfo *II = ND->getIdentifier();
1055     assert(II && "Attempt to mangle unnamed decl.");
1056     const auto *FD = dyn_cast<FunctionDecl>(ND);
1057 
1058     if (FD &&
1059         FD->getType()->castAs<FunctionType>()->getCallConv() == CC_X86RegCall) {
1060       Out << "__regcall3__" << II->getName();
1061     } else if (FD && FD->hasAttr<CUDAGlobalAttr>() &&
1062                GD.getKernelReferenceKind() == KernelReferenceKind::Stub) {
1063       Out << "__device_stub__" << II->getName();
1064     } else {
1065       Out << II->getName();
1066     }
1067   }
1068 
1069   if (const auto *FD = dyn_cast<FunctionDecl>(ND))
1070     if (FD->isMultiVersion() && !OmitMultiVersionMangling) {
1071       switch (FD->getMultiVersionKind()) {
1072       case MultiVersionKind::CPUDispatch:
1073       case MultiVersionKind::CPUSpecific:
1074         AppendCPUSpecificCPUDispatchMangling(CGM,
1075                                              FD->getAttr<CPUSpecificAttr>(),
1076                                              GD.getMultiVersionIndex(), Out);
1077         break;
1078       case MultiVersionKind::Target:
1079         AppendTargetMangling(CGM, FD->getAttr<TargetAttr>(), Out);
1080         break;
1081       case MultiVersionKind::None:
1082         llvm_unreachable("None multiversion type isn't valid here");
1083       }
1084     }
1085 
1086   return std::string(Out.str());
1087 }
1088 
1089 void CodeGenModule::UpdateMultiVersionNames(GlobalDecl GD,
1090                                             const FunctionDecl *FD) {
1091   if (!FD->isMultiVersion())
1092     return;
1093 
1094   // Get the name of what this would be without the 'target' attribute.  This
1095   // allows us to lookup the version that was emitted when this wasn't a
1096   // multiversion function.
1097   std::string NonTargetName =
1098       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
1099   GlobalDecl OtherGD;
1100   if (lookupRepresentativeDecl(NonTargetName, OtherGD)) {
1101     assert(OtherGD.getCanonicalDecl()
1102                .getDecl()
1103                ->getAsFunction()
1104                ->isMultiVersion() &&
1105            "Other GD should now be a multiversioned function");
1106     // OtherFD is the version of this function that was mangled BEFORE
1107     // becoming a MultiVersion function.  It potentially needs to be updated.
1108     const FunctionDecl *OtherFD = OtherGD.getCanonicalDecl()
1109                                       .getDecl()
1110                                       ->getAsFunction()
1111                                       ->getMostRecentDecl();
1112     std::string OtherName = getMangledNameImpl(*this, OtherGD, OtherFD);
1113     // This is so that if the initial version was already the 'default'
1114     // version, we don't try to update it.
1115     if (OtherName != NonTargetName) {
1116       // Remove instead of erase, since others may have stored the StringRef
1117       // to this.
1118       const auto ExistingRecord = Manglings.find(NonTargetName);
1119       if (ExistingRecord != std::end(Manglings))
1120         Manglings.remove(&(*ExistingRecord));
1121       auto Result = Manglings.insert(std::make_pair(OtherName, OtherGD));
1122       MangledDeclNames[OtherGD.getCanonicalDecl()] = Result.first->first();
1123       if (llvm::GlobalValue *Entry = GetGlobalValue(NonTargetName))
1124         Entry->setName(OtherName);
1125     }
1126   }
1127 }
1128 
1129 StringRef CodeGenModule::getMangledName(GlobalDecl GD) {
1130   GlobalDecl CanonicalGD = GD.getCanonicalDecl();
1131 
1132   // Some ABIs don't have constructor variants.  Make sure that base and
1133   // complete constructors get mangled the same.
1134   if (const auto *CD = dyn_cast<CXXConstructorDecl>(CanonicalGD.getDecl())) {
1135     if (!getTarget().getCXXABI().hasConstructorVariants()) {
1136       CXXCtorType OrigCtorType = GD.getCtorType();
1137       assert(OrigCtorType == Ctor_Base || OrigCtorType == Ctor_Complete);
1138       if (OrigCtorType == Ctor_Base)
1139         CanonicalGD = GlobalDecl(CD, Ctor_Complete);
1140     }
1141   }
1142 
1143   auto FoundName = MangledDeclNames.find(CanonicalGD);
1144   if (FoundName != MangledDeclNames.end())
1145     return FoundName->second;
1146 
1147   // Keep the first result in the case of a mangling collision.
1148   const auto *ND = cast<NamedDecl>(GD.getDecl());
1149   std::string MangledName = getMangledNameImpl(*this, GD, ND);
1150 
1151   // Ensure either we have different ABIs between host and device compilations,
1152   // says host compilation following MSVC ABI but device compilation follows
1153   // Itanium C++ ABI or, if they follow the same ABI, kernel names after
1154   // mangling should be the same after name stubbing. The later checking is
1155   // very important as the device kernel name being mangled in host-compilation
1156   // is used to resolve the device binaries to be executed. Inconsistent naming
1157   // result in undefined behavior. Even though we cannot check that naming
1158   // directly between host- and device-compilations, the host- and
1159   // device-mangling in host compilation could help catching certain ones.
1160   assert(!isa<FunctionDecl>(ND) || !ND->hasAttr<CUDAGlobalAttr>() ||
1161          getLangOpts().CUDAIsDevice ||
1162          (getContext().getAuxTargetInfo() &&
1163           (getContext().getAuxTargetInfo()->getCXXABI() !=
1164            getContext().getTargetInfo().getCXXABI())) ||
1165          getCUDARuntime().getDeviceSideName(ND) ==
1166              getMangledNameImpl(
1167                  *this,
1168                  GD.getWithKernelReferenceKind(KernelReferenceKind::Kernel),
1169                  ND));
1170 
1171   auto Result = Manglings.insert(std::make_pair(MangledName, GD));
1172   return MangledDeclNames[CanonicalGD] = Result.first->first();
1173 }
1174 
1175 StringRef CodeGenModule::getBlockMangledName(GlobalDecl GD,
1176                                              const BlockDecl *BD) {
1177   MangleContext &MangleCtx = getCXXABI().getMangleContext();
1178   const Decl *D = GD.getDecl();
1179 
1180   SmallString<256> Buffer;
1181   llvm::raw_svector_ostream Out(Buffer);
1182   if (!D)
1183     MangleCtx.mangleGlobalBlock(BD,
1184       dyn_cast_or_null<VarDecl>(initializedGlobalDecl.getDecl()), Out);
1185   else if (const auto *CD = dyn_cast<CXXConstructorDecl>(D))
1186     MangleCtx.mangleCtorBlock(CD, GD.getCtorType(), BD, Out);
1187   else if (const auto *DD = dyn_cast<CXXDestructorDecl>(D))
1188     MangleCtx.mangleDtorBlock(DD, GD.getDtorType(), BD, Out);
1189   else
1190     MangleCtx.mangleBlock(cast<DeclContext>(D), BD, Out);
1191 
1192   auto Result = Manglings.insert(std::make_pair(Out.str(), BD));
1193   return Result.first->first();
1194 }
1195 
1196 llvm::GlobalValue *CodeGenModule::GetGlobalValue(StringRef Name) {
1197   return getModule().getNamedValue(Name);
1198 }
1199 
1200 /// AddGlobalCtor - Add a function to the list that will be called before
1201 /// main() runs.
1202 void CodeGenModule::AddGlobalCtor(llvm::Function *Ctor, int Priority,
1203                                   llvm::Constant *AssociatedData) {
1204   // FIXME: Type coercion of void()* types.
1205   GlobalCtors.push_back(Structor(Priority, Ctor, AssociatedData));
1206 }
1207 
1208 /// AddGlobalDtor - Add a function to the list that will be called
1209 /// when the module is unloaded.
1210 void CodeGenModule::AddGlobalDtor(llvm::Function *Dtor, int Priority) {
1211   if (CodeGenOpts.RegisterGlobalDtorsWithAtExit) {
1212     if (getCXXABI().useSinitAndSterm())
1213       llvm::report_fatal_error(
1214           "register global dtors with atexit() is not supported yet");
1215     DtorsUsingAtExit[Priority].push_back(Dtor);
1216     return;
1217   }
1218 
1219   // FIXME: Type coercion of void()* types.
1220   GlobalDtors.push_back(Structor(Priority, Dtor, nullptr));
1221 }
1222 
1223 void CodeGenModule::EmitCtorList(CtorList &Fns, const char *GlobalName) {
1224   if (Fns.empty()) return;
1225 
1226   // Ctor function type is void()*.
1227   llvm::FunctionType* CtorFTy = llvm::FunctionType::get(VoidTy, false);
1228   llvm::Type *CtorPFTy = llvm::PointerType::get(CtorFTy,
1229       TheModule.getDataLayout().getProgramAddressSpace());
1230 
1231   // Get the type of a ctor entry, { i32, void ()*, i8* }.
1232   llvm::StructType *CtorStructTy = llvm::StructType::get(
1233       Int32Ty, CtorPFTy, VoidPtrTy);
1234 
1235   // Construct the constructor and destructor arrays.
1236   ConstantInitBuilder builder(*this);
1237   auto ctors = builder.beginArray(CtorStructTy);
1238   for (const auto &I : Fns) {
1239     auto ctor = ctors.beginStruct(CtorStructTy);
1240     ctor.addInt(Int32Ty, I.Priority);
1241     ctor.add(llvm::ConstantExpr::getBitCast(I.Initializer, CtorPFTy));
1242     if (I.AssociatedData)
1243       ctor.add(llvm::ConstantExpr::getBitCast(I.AssociatedData, VoidPtrTy));
1244     else
1245       ctor.addNullPointer(VoidPtrTy);
1246     ctor.finishAndAddTo(ctors);
1247   }
1248 
1249   auto list =
1250     ctors.finishAndCreateGlobal(GlobalName, getPointerAlign(),
1251                                 /*constant*/ false,
1252                                 llvm::GlobalValue::AppendingLinkage);
1253 
1254   // The LTO linker doesn't seem to like it when we set an alignment
1255   // on appending variables.  Take it off as a workaround.
1256   list->setAlignment(llvm::None);
1257 
1258   Fns.clear();
1259 }
1260 
1261 llvm::GlobalValue::LinkageTypes
1262 CodeGenModule::getFunctionLinkage(GlobalDecl GD) {
1263   const auto *D = cast<FunctionDecl>(GD.getDecl());
1264 
1265   GVALinkage Linkage = getContext().GetGVALinkageForFunction(D);
1266 
1267   if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(D))
1268     return getCXXABI().getCXXDestructorLinkage(Linkage, Dtor, GD.getDtorType());
1269 
1270   if (isa<CXXConstructorDecl>(D) &&
1271       cast<CXXConstructorDecl>(D)->isInheritingConstructor() &&
1272       Context.getTargetInfo().getCXXABI().isMicrosoft()) {
1273     // Our approach to inheriting constructors is fundamentally different from
1274     // that used by the MS ABI, so keep our inheriting constructor thunks
1275     // internal rather than trying to pick an unambiguous mangling for them.
1276     return llvm::GlobalValue::InternalLinkage;
1277   }
1278 
1279   return getLLVMLinkageForDeclarator(D, Linkage, /*IsConstantVariable=*/false);
1280 }
1281 
1282 llvm::ConstantInt *CodeGenModule::CreateCrossDsoCfiTypeId(llvm::Metadata *MD) {
1283   llvm::MDString *MDS = dyn_cast<llvm::MDString>(MD);
1284   if (!MDS) return nullptr;
1285 
1286   return llvm::ConstantInt::get(Int64Ty, llvm::MD5Hash(MDS->getString()));
1287 }
1288 
1289 void CodeGenModule::SetLLVMFunctionAttributes(GlobalDecl GD,
1290                                               const CGFunctionInfo &Info,
1291                                               llvm::Function *F) {
1292   unsigned CallingConv;
1293   llvm::AttributeList PAL;
1294   ConstructAttributeList(F->getName(), Info, GD, PAL, CallingConv, false);
1295   F->setAttributes(PAL);
1296   F->setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
1297 }
1298 
1299 static void removeImageAccessQualifier(std::string& TyName) {
1300   std::string ReadOnlyQual("__read_only");
1301   std::string::size_type ReadOnlyPos = TyName.find(ReadOnlyQual);
1302   if (ReadOnlyPos != std::string::npos)
1303     // "+ 1" for the space after access qualifier.
1304     TyName.erase(ReadOnlyPos, ReadOnlyQual.size() + 1);
1305   else {
1306     std::string WriteOnlyQual("__write_only");
1307     std::string::size_type WriteOnlyPos = TyName.find(WriteOnlyQual);
1308     if (WriteOnlyPos != std::string::npos)
1309       TyName.erase(WriteOnlyPos, WriteOnlyQual.size() + 1);
1310     else {
1311       std::string ReadWriteQual("__read_write");
1312       std::string::size_type ReadWritePos = TyName.find(ReadWriteQual);
1313       if (ReadWritePos != std::string::npos)
1314         TyName.erase(ReadWritePos, ReadWriteQual.size() + 1);
1315     }
1316   }
1317 }
1318 
1319 // Returns the address space id that should be produced to the
1320 // kernel_arg_addr_space metadata. This is always fixed to the ids
1321 // as specified in the SPIR 2.0 specification in order to differentiate
1322 // for example in clGetKernelArgInfo() implementation between the address
1323 // spaces with targets without unique mapping to the OpenCL address spaces
1324 // (basically all single AS CPUs).
1325 static unsigned ArgInfoAddressSpace(LangAS AS) {
1326   switch (AS) {
1327   case LangAS::opencl_global:
1328     return 1;
1329   case LangAS::opencl_constant:
1330     return 2;
1331   case LangAS::opencl_local:
1332     return 3;
1333   case LangAS::opencl_generic:
1334     return 4; // Not in SPIR 2.0 specs.
1335   case LangAS::opencl_global_device:
1336     return 5;
1337   case LangAS::opencl_global_host:
1338     return 6;
1339   default:
1340     return 0; // Assume private.
1341   }
1342 }
1343 
1344 void CodeGenModule::GenOpenCLArgMetadata(llvm::Function *Fn,
1345                                          const FunctionDecl *FD,
1346                                          CodeGenFunction *CGF) {
1347   assert(((FD && CGF) || (!FD && !CGF)) &&
1348          "Incorrect use - FD and CGF should either be both null or not!");
1349   // Create MDNodes that represent the kernel arg metadata.
1350   // Each MDNode is a list in the form of "key", N number of values which is
1351   // the same number of values as their are kernel arguments.
1352 
1353   const PrintingPolicy &Policy = Context.getPrintingPolicy();
1354 
1355   // MDNode for the kernel argument address space qualifiers.
1356   SmallVector<llvm::Metadata *, 8> addressQuals;
1357 
1358   // MDNode for the kernel argument access qualifiers (images only).
1359   SmallVector<llvm::Metadata *, 8> accessQuals;
1360 
1361   // MDNode for the kernel argument type names.
1362   SmallVector<llvm::Metadata *, 8> argTypeNames;
1363 
1364   // MDNode for the kernel argument base type names.
1365   SmallVector<llvm::Metadata *, 8> argBaseTypeNames;
1366 
1367   // MDNode for the kernel argument type qualifiers.
1368   SmallVector<llvm::Metadata *, 8> argTypeQuals;
1369 
1370   // MDNode for the kernel argument names.
1371   SmallVector<llvm::Metadata *, 8> argNames;
1372 
1373   if (FD && CGF)
1374     for (unsigned i = 0, e = FD->getNumParams(); i != e; ++i) {
1375       const ParmVarDecl *parm = FD->getParamDecl(i);
1376       QualType ty = parm->getType();
1377       std::string typeQuals;
1378 
1379       if (ty->isPointerType()) {
1380         QualType pointeeTy = ty->getPointeeType();
1381 
1382         // Get address qualifier.
1383         addressQuals.push_back(
1384             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(
1385                 ArgInfoAddressSpace(pointeeTy.getAddressSpace()))));
1386 
1387         // Get argument type name.
1388         std::string typeName =
1389             pointeeTy.getUnqualifiedType().getAsString(Policy) + "*";
1390 
1391         // Turn "unsigned type" to "utype"
1392         std::string::size_type pos = typeName.find("unsigned");
1393         if (pointeeTy.isCanonical() && pos != std::string::npos)
1394           typeName.erase(pos + 1, 8);
1395 
1396         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
1397 
1398         std::string baseTypeName =
1399             pointeeTy.getUnqualifiedType().getCanonicalType().getAsString(
1400                 Policy) +
1401             "*";
1402 
1403         // Turn "unsigned type" to "utype"
1404         pos = baseTypeName.find("unsigned");
1405         if (pos != std::string::npos)
1406           baseTypeName.erase(pos + 1, 8);
1407 
1408         argBaseTypeNames.push_back(
1409             llvm::MDString::get(VMContext, baseTypeName));
1410 
1411         // Get argument type qualifiers:
1412         if (ty.isRestrictQualified())
1413           typeQuals = "restrict";
1414         if (pointeeTy.isConstQualified() ||
1415             (pointeeTy.getAddressSpace() == LangAS::opencl_constant))
1416           typeQuals += typeQuals.empty() ? "const" : " const";
1417         if (pointeeTy.isVolatileQualified())
1418           typeQuals += typeQuals.empty() ? "volatile" : " volatile";
1419       } else {
1420         uint32_t AddrSpc = 0;
1421         bool isPipe = ty->isPipeType();
1422         if (ty->isImageType() || isPipe)
1423           AddrSpc = ArgInfoAddressSpace(LangAS::opencl_global);
1424 
1425         addressQuals.push_back(
1426             llvm::ConstantAsMetadata::get(CGF->Builder.getInt32(AddrSpc)));
1427 
1428         // Get argument type name.
1429         std::string typeName;
1430         if (isPipe)
1431           typeName = ty.getCanonicalType()
1432                          ->castAs<PipeType>()
1433                          ->getElementType()
1434                          .getAsString(Policy);
1435         else
1436           typeName = ty.getUnqualifiedType().getAsString(Policy);
1437 
1438         // Turn "unsigned type" to "utype"
1439         std::string::size_type pos = typeName.find("unsigned");
1440         if (ty.isCanonical() && pos != std::string::npos)
1441           typeName.erase(pos + 1, 8);
1442 
1443         std::string baseTypeName;
1444         if (isPipe)
1445           baseTypeName = ty.getCanonicalType()
1446                              ->castAs<PipeType>()
1447                              ->getElementType()
1448                              .getCanonicalType()
1449                              .getAsString(Policy);
1450         else
1451           baseTypeName =
1452               ty.getUnqualifiedType().getCanonicalType().getAsString(Policy);
1453 
1454         // Remove access qualifiers on images
1455         // (as they are inseparable from type in clang implementation,
1456         // but OpenCL spec provides a special query to get access qualifier
1457         // via clGetKernelArgInfo with CL_KERNEL_ARG_ACCESS_QUALIFIER):
1458         if (ty->isImageType()) {
1459           removeImageAccessQualifier(typeName);
1460           removeImageAccessQualifier(baseTypeName);
1461         }
1462 
1463         argTypeNames.push_back(llvm::MDString::get(VMContext, typeName));
1464 
1465         // Turn "unsigned type" to "utype"
1466         pos = baseTypeName.find("unsigned");
1467         if (pos != std::string::npos)
1468           baseTypeName.erase(pos + 1, 8);
1469 
1470         argBaseTypeNames.push_back(
1471             llvm::MDString::get(VMContext, baseTypeName));
1472 
1473         if (isPipe)
1474           typeQuals = "pipe";
1475       }
1476 
1477       argTypeQuals.push_back(llvm::MDString::get(VMContext, typeQuals));
1478 
1479       // Get image and pipe access qualifier:
1480       if (ty->isImageType() || ty->isPipeType()) {
1481         const Decl *PDecl = parm;
1482         if (auto *TD = dyn_cast<TypedefType>(ty))
1483           PDecl = TD->getDecl();
1484         const OpenCLAccessAttr *A = PDecl->getAttr<OpenCLAccessAttr>();
1485         if (A && A->isWriteOnly())
1486           accessQuals.push_back(llvm::MDString::get(VMContext, "write_only"));
1487         else if (A && A->isReadWrite())
1488           accessQuals.push_back(llvm::MDString::get(VMContext, "read_write"));
1489         else
1490           accessQuals.push_back(llvm::MDString::get(VMContext, "read_only"));
1491       } else
1492         accessQuals.push_back(llvm::MDString::get(VMContext, "none"));
1493 
1494       // Get argument name.
1495       argNames.push_back(llvm::MDString::get(VMContext, parm->getName()));
1496     }
1497 
1498   Fn->setMetadata("kernel_arg_addr_space",
1499                   llvm::MDNode::get(VMContext, addressQuals));
1500   Fn->setMetadata("kernel_arg_access_qual",
1501                   llvm::MDNode::get(VMContext, accessQuals));
1502   Fn->setMetadata("kernel_arg_type",
1503                   llvm::MDNode::get(VMContext, argTypeNames));
1504   Fn->setMetadata("kernel_arg_base_type",
1505                   llvm::MDNode::get(VMContext, argBaseTypeNames));
1506   Fn->setMetadata("kernel_arg_type_qual",
1507                   llvm::MDNode::get(VMContext, argTypeQuals));
1508   if (getCodeGenOpts().EmitOpenCLArgMetadata)
1509     Fn->setMetadata("kernel_arg_name",
1510                     llvm::MDNode::get(VMContext, argNames));
1511 }
1512 
1513 /// Determines whether the language options require us to model
1514 /// unwind exceptions.  We treat -fexceptions as mandating this
1515 /// except under the fragile ObjC ABI with only ObjC exceptions
1516 /// enabled.  This means, for example, that C with -fexceptions
1517 /// enables this.
1518 static bool hasUnwindExceptions(const LangOptions &LangOpts) {
1519   // If exceptions are completely disabled, obviously this is false.
1520   if (!LangOpts.Exceptions) return false;
1521 
1522   // If C++ exceptions are enabled, this is true.
1523   if (LangOpts.CXXExceptions) return true;
1524 
1525   // If ObjC exceptions are enabled, this depends on the ABI.
1526   if (LangOpts.ObjCExceptions) {
1527     return LangOpts.ObjCRuntime.hasUnwindExceptions();
1528   }
1529 
1530   return true;
1531 }
1532 
1533 static bool requiresMemberFunctionPointerTypeMetadata(CodeGenModule &CGM,
1534                                                       const CXXMethodDecl *MD) {
1535   // Check that the type metadata can ever actually be used by a call.
1536   if (!CGM.getCodeGenOpts().LTOUnit ||
1537       !CGM.HasHiddenLTOVisibility(MD->getParent()))
1538     return false;
1539 
1540   // Only functions whose address can be taken with a member function pointer
1541   // need this sort of type metadata.
1542   return !MD->isStatic() && !MD->isVirtual() && !isa<CXXConstructorDecl>(MD) &&
1543          !isa<CXXDestructorDecl>(MD);
1544 }
1545 
1546 std::vector<const CXXRecordDecl *>
1547 CodeGenModule::getMostBaseClasses(const CXXRecordDecl *RD) {
1548   llvm::SetVector<const CXXRecordDecl *> MostBases;
1549 
1550   std::function<void (const CXXRecordDecl *)> CollectMostBases;
1551   CollectMostBases = [&](const CXXRecordDecl *RD) {
1552     if (RD->getNumBases() == 0)
1553       MostBases.insert(RD);
1554     for (const CXXBaseSpecifier &B : RD->bases())
1555       CollectMostBases(B.getType()->getAsCXXRecordDecl());
1556   };
1557   CollectMostBases(RD);
1558   return MostBases.takeVector();
1559 }
1560 
1561 void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
1562                                                            llvm::Function *F) {
1563   llvm::AttrBuilder B;
1564 
1565   if (CodeGenOpts.UnwindTables)
1566     B.addAttribute(llvm::Attribute::UWTable);
1567 
1568   if (CodeGenOpts.StackClashProtector)
1569     B.addAttribute("probe-stack", "inline-asm");
1570 
1571   if (!hasUnwindExceptions(LangOpts))
1572     B.addAttribute(llvm::Attribute::NoUnwind);
1573 
1574   if (!D || !D->hasAttr<NoStackProtectorAttr>()) {
1575     if (LangOpts.getStackProtector() == LangOptions::SSPOn)
1576       B.addAttribute(llvm::Attribute::StackProtect);
1577     else if (LangOpts.getStackProtector() == LangOptions::SSPStrong)
1578       B.addAttribute(llvm::Attribute::StackProtectStrong);
1579     else if (LangOpts.getStackProtector() == LangOptions::SSPReq)
1580       B.addAttribute(llvm::Attribute::StackProtectReq);
1581   }
1582 
1583   if (!D) {
1584     // If we don't have a declaration to control inlining, the function isn't
1585     // explicitly marked as alwaysinline for semantic reasons, and inlining is
1586     // disabled, mark the function as noinline.
1587     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline) &&
1588         CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining)
1589       B.addAttribute(llvm::Attribute::NoInline);
1590 
1591     F->addAttributes(llvm::AttributeList::FunctionIndex, B);
1592     return;
1593   }
1594 
1595   // Track whether we need to add the optnone LLVM attribute,
1596   // starting with the default for this optimization level.
1597   bool ShouldAddOptNone =
1598       !CodeGenOpts.DisableO0ImplyOptNone && CodeGenOpts.OptimizationLevel == 0;
1599   // We can't add optnone in the following cases, it won't pass the verifier.
1600   ShouldAddOptNone &= !D->hasAttr<MinSizeAttr>();
1601   ShouldAddOptNone &= !D->hasAttr<AlwaysInlineAttr>();
1602 
1603   // Add optnone, but do so only if the function isn't always_inline.
1604   if ((ShouldAddOptNone || D->hasAttr<OptimizeNoneAttr>()) &&
1605       !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
1606     B.addAttribute(llvm::Attribute::OptimizeNone);
1607 
1608     // OptimizeNone implies noinline; we should not be inlining such functions.
1609     B.addAttribute(llvm::Attribute::NoInline);
1610 
1611     // We still need to handle naked functions even though optnone subsumes
1612     // much of their semantics.
1613     if (D->hasAttr<NakedAttr>())
1614       B.addAttribute(llvm::Attribute::Naked);
1615 
1616     // OptimizeNone wins over OptimizeForSize and MinSize.
1617     F->removeFnAttr(llvm::Attribute::OptimizeForSize);
1618     F->removeFnAttr(llvm::Attribute::MinSize);
1619   } else if (D->hasAttr<NakedAttr>()) {
1620     // Naked implies noinline: we should not be inlining such functions.
1621     B.addAttribute(llvm::Attribute::Naked);
1622     B.addAttribute(llvm::Attribute::NoInline);
1623   } else if (D->hasAttr<NoDuplicateAttr>()) {
1624     B.addAttribute(llvm::Attribute::NoDuplicate);
1625   } else if (D->hasAttr<NoInlineAttr>() && !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
1626     // Add noinline if the function isn't always_inline.
1627     B.addAttribute(llvm::Attribute::NoInline);
1628   } else if (D->hasAttr<AlwaysInlineAttr>() &&
1629              !F->hasFnAttribute(llvm::Attribute::NoInline)) {
1630     // (noinline wins over always_inline, and we can't specify both in IR)
1631     B.addAttribute(llvm::Attribute::AlwaysInline);
1632   } else if (CodeGenOpts.getInlining() == CodeGenOptions::OnlyAlwaysInlining) {
1633     // If we're not inlining, then force everything that isn't always_inline to
1634     // carry an explicit noinline attribute.
1635     if (!F->hasFnAttribute(llvm::Attribute::AlwaysInline))
1636       B.addAttribute(llvm::Attribute::NoInline);
1637   } else {
1638     // Otherwise, propagate the inline hint attribute and potentially use its
1639     // absence to mark things as noinline.
1640     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
1641       // Search function and template pattern redeclarations for inline.
1642       auto CheckForInline = [](const FunctionDecl *FD) {
1643         auto CheckRedeclForInline = [](const FunctionDecl *Redecl) {
1644           return Redecl->isInlineSpecified();
1645         };
1646         if (any_of(FD->redecls(), CheckRedeclForInline))
1647           return true;
1648         const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern();
1649         if (!Pattern)
1650           return false;
1651         return any_of(Pattern->redecls(), CheckRedeclForInline);
1652       };
1653       if (CheckForInline(FD)) {
1654         B.addAttribute(llvm::Attribute::InlineHint);
1655       } else if (CodeGenOpts.getInlining() ==
1656                      CodeGenOptions::OnlyHintInlining &&
1657                  !FD->isInlined() &&
1658                  !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
1659         B.addAttribute(llvm::Attribute::NoInline);
1660       }
1661     }
1662   }
1663 
1664   // Add other optimization related attributes if we are optimizing this
1665   // function.
1666   if (!D->hasAttr<OptimizeNoneAttr>()) {
1667     if (D->hasAttr<ColdAttr>()) {
1668       if (!ShouldAddOptNone)
1669         B.addAttribute(llvm::Attribute::OptimizeForSize);
1670       B.addAttribute(llvm::Attribute::Cold);
1671     }
1672 
1673     if (D->hasAttr<MinSizeAttr>())
1674       B.addAttribute(llvm::Attribute::MinSize);
1675   }
1676 
1677   F->addAttributes(llvm::AttributeList::FunctionIndex, B);
1678 
1679   unsigned alignment = D->getMaxAlignment() / Context.getCharWidth();
1680   if (alignment)
1681     F->setAlignment(llvm::Align(alignment));
1682 
1683   if (!D->hasAttr<AlignedAttr>())
1684     if (LangOpts.FunctionAlignment)
1685       F->setAlignment(llvm::Align(1ull << LangOpts.FunctionAlignment));
1686 
1687   // Some C++ ABIs require 2-byte alignment for member functions, in order to
1688   // reserve a bit for differentiating between virtual and non-virtual member
1689   // functions. If the current target's C++ ABI requires this and this is a
1690   // member function, set its alignment accordingly.
1691   if (getTarget().getCXXABI().areMemberFunctionsAligned()) {
1692     if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
1693       F->setAlignment(llvm::Align(2));
1694   }
1695 
1696   // In the cross-dso CFI mode with canonical jump tables, we want !type
1697   // attributes on definitions only.
1698   if (CodeGenOpts.SanitizeCfiCrossDso &&
1699       CodeGenOpts.SanitizeCfiCanonicalJumpTables) {
1700     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
1701       // Skip available_externally functions. They won't be codegen'ed in the
1702       // current module anyway.
1703       if (getContext().GetGVALinkageForFunction(FD) != GVA_AvailableExternally)
1704         CreateFunctionTypeMetadataForIcall(FD, F);
1705     }
1706   }
1707 
1708   // Emit type metadata on member functions for member function pointer checks.
1709   // These are only ever necessary on definitions; we're guaranteed that the
1710   // definition will be present in the LTO unit as a result of LTO visibility.
1711   auto *MD = dyn_cast<CXXMethodDecl>(D);
1712   if (MD && requiresMemberFunctionPointerTypeMetadata(*this, MD)) {
1713     for (const CXXRecordDecl *Base : getMostBaseClasses(MD->getParent())) {
1714       llvm::Metadata *Id =
1715           CreateMetadataIdentifierForType(Context.getMemberPointerType(
1716               MD->getType(), Context.getRecordType(Base).getTypePtr()));
1717       F->addTypeMetadata(0, Id);
1718     }
1719   }
1720 }
1721 
1722 void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
1723   const Decl *D = GD.getDecl();
1724   if (dyn_cast_or_null<NamedDecl>(D))
1725     setGVProperties(GV, GD);
1726   else
1727     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
1728 
1729   if (D && D->hasAttr<UsedAttr>())
1730     addUsedGlobal(GV);
1731 
1732   if (CodeGenOpts.KeepStaticConsts && D && isa<VarDecl>(D)) {
1733     const auto *VD = cast<VarDecl>(D);
1734     if (VD->getType().isConstQualified() &&
1735         VD->getStorageDuration() == SD_Static)
1736       addUsedGlobal(GV);
1737   }
1738 }
1739 
1740 bool CodeGenModule::GetCPUAndFeaturesAttributes(GlobalDecl GD,
1741                                                 llvm::AttrBuilder &Attrs) {
1742   // Add target-cpu and target-features attributes to functions. If
1743   // we have a decl for the function and it has a target attribute then
1744   // parse that and add it to the feature set.
1745   StringRef TargetCPU = getTarget().getTargetOpts().CPU;
1746   std::vector<std::string> Features;
1747   const auto *FD = dyn_cast_or_null<FunctionDecl>(GD.getDecl());
1748   FD = FD ? FD->getMostRecentDecl() : FD;
1749   const auto *TD = FD ? FD->getAttr<TargetAttr>() : nullptr;
1750   const auto *SD = FD ? FD->getAttr<CPUSpecificAttr>() : nullptr;
1751   bool AddedAttr = false;
1752   if (TD || SD) {
1753     llvm::StringMap<bool> FeatureMap;
1754     getContext().getFunctionFeatureMap(FeatureMap, GD);
1755 
1756     // Produce the canonical string for this set of features.
1757     for (const llvm::StringMap<bool>::value_type &Entry : FeatureMap)
1758       Features.push_back((Entry.getValue() ? "+" : "-") + Entry.getKey().str());
1759 
1760     // Now add the target-cpu and target-features to the function.
1761     // While we populated the feature map above, we still need to
1762     // get and parse the target attribute so we can get the cpu for
1763     // the function.
1764     if (TD) {
1765       ParsedTargetAttr ParsedAttr = TD->parse();
1766       if (ParsedAttr.Architecture != "" &&
1767           getTarget().isValidCPUName(ParsedAttr.Architecture))
1768         TargetCPU = ParsedAttr.Architecture;
1769     }
1770   } else {
1771     // Otherwise just add the existing target cpu and target features to the
1772     // function.
1773     Features = getTarget().getTargetOpts().Features;
1774   }
1775 
1776   if (TargetCPU != "") {
1777     Attrs.addAttribute("target-cpu", TargetCPU);
1778     AddedAttr = true;
1779   }
1780   if (!Features.empty()) {
1781     llvm::sort(Features);
1782     Attrs.addAttribute("target-features", llvm::join(Features, ","));
1783     AddedAttr = true;
1784   }
1785 
1786   return AddedAttr;
1787 }
1788 
1789 void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
1790                                           llvm::GlobalObject *GO) {
1791   const Decl *D = GD.getDecl();
1792   SetCommonAttributes(GD, GO);
1793 
1794   if (D) {
1795     if (auto *GV = dyn_cast<llvm::GlobalVariable>(GO)) {
1796       if (auto *SA = D->getAttr<PragmaClangBSSSectionAttr>())
1797         GV->addAttribute("bss-section", SA->getName());
1798       if (auto *SA = D->getAttr<PragmaClangDataSectionAttr>())
1799         GV->addAttribute("data-section", SA->getName());
1800       if (auto *SA = D->getAttr<PragmaClangRodataSectionAttr>())
1801         GV->addAttribute("rodata-section", SA->getName());
1802       if (auto *SA = D->getAttr<PragmaClangRelroSectionAttr>())
1803         GV->addAttribute("relro-section", SA->getName());
1804     }
1805 
1806     if (auto *F = dyn_cast<llvm::Function>(GO)) {
1807       if (auto *SA = D->getAttr<PragmaClangTextSectionAttr>())
1808         if (!D->getAttr<SectionAttr>())
1809           F->addFnAttr("implicit-section-name", SA->getName());
1810 
1811       llvm::AttrBuilder Attrs;
1812       if (GetCPUAndFeaturesAttributes(GD, Attrs)) {
1813         // We know that GetCPUAndFeaturesAttributes will always have the
1814         // newest set, since it has the newest possible FunctionDecl, so the
1815         // new ones should replace the old.
1816         F->removeFnAttr("target-cpu");
1817         F->removeFnAttr("target-features");
1818         F->addAttributes(llvm::AttributeList::FunctionIndex, Attrs);
1819       }
1820     }
1821 
1822     if (const auto *CSA = D->getAttr<CodeSegAttr>())
1823       GO->setSection(CSA->getName());
1824     else if (const auto *SA = D->getAttr<SectionAttr>())
1825       GO->setSection(SA->getName());
1826   }
1827 
1828   getTargetCodeGenInfo().setTargetAttributes(D, GO, *this);
1829 }
1830 
1831 void CodeGenModule::SetInternalFunctionAttributes(GlobalDecl GD,
1832                                                   llvm::Function *F,
1833                                                   const CGFunctionInfo &FI) {
1834   const Decl *D = GD.getDecl();
1835   SetLLVMFunctionAttributes(GD, FI, F);
1836   SetLLVMFunctionAttributesForDefinition(D, F);
1837 
1838   F->setLinkage(llvm::Function::InternalLinkage);
1839 
1840   setNonAliasAttributes(GD, F);
1841 }
1842 
1843 static void setLinkageForGV(llvm::GlobalValue *GV, const NamedDecl *ND) {
1844   // Set linkage and visibility in case we never see a definition.
1845   LinkageInfo LV = ND->getLinkageAndVisibility();
1846   // Don't set internal linkage on declarations.
1847   // "extern_weak" is overloaded in LLVM; we probably should have
1848   // separate linkage types for this.
1849   if (isExternallyVisible(LV.getLinkage()) &&
1850       (ND->hasAttr<WeakAttr>() || ND->isWeakImported()))
1851     GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
1852 }
1853 
1854 void CodeGenModule::CreateFunctionTypeMetadataForIcall(const FunctionDecl *FD,
1855                                                        llvm::Function *F) {
1856   // Only if we are checking indirect calls.
1857   if (!LangOpts.Sanitize.has(SanitizerKind::CFIICall))
1858     return;
1859 
1860   // Non-static class methods are handled via vtable or member function pointer
1861   // checks elsewhere.
1862   if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic())
1863     return;
1864 
1865   llvm::Metadata *MD = CreateMetadataIdentifierForType(FD->getType());
1866   F->addTypeMetadata(0, MD);
1867   F->addTypeMetadata(0, CreateMetadataIdentifierGeneralized(FD->getType()));
1868 
1869   // Emit a hash-based bit set entry for cross-DSO calls.
1870   if (CodeGenOpts.SanitizeCfiCrossDso)
1871     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
1872       F->addTypeMetadata(0, llvm::ConstantAsMetadata::get(CrossDsoTypeId));
1873 }
1874 
1875 void CodeGenModule::SetFunctionAttributes(GlobalDecl GD, llvm::Function *F,
1876                                           bool IsIncompleteFunction,
1877                                           bool IsThunk) {
1878 
1879   if (llvm::Intrinsic::ID IID = F->getIntrinsicID()) {
1880     // If this is an intrinsic function, set the function's attributes
1881     // to the intrinsic's attributes.
1882     F->setAttributes(llvm::Intrinsic::getAttributes(getLLVMContext(), IID));
1883     return;
1884   }
1885 
1886   const auto *FD = cast<FunctionDecl>(GD.getDecl());
1887 
1888   if (!IsIncompleteFunction)
1889     SetLLVMFunctionAttributes(GD, getTypes().arrangeGlobalDeclaration(GD), F);
1890 
1891   // Add the Returned attribute for "this", except for iOS 5 and earlier
1892   // where substantial code, including the libstdc++ dylib, was compiled with
1893   // GCC and does not actually return "this".
1894   if (!IsThunk && getCXXABI().HasThisReturn(GD) &&
1895       !(getTriple().isiOS() && getTriple().isOSVersionLT(6))) {
1896     assert(!F->arg_empty() &&
1897            F->arg_begin()->getType()
1898              ->canLosslesslyBitCastTo(F->getReturnType()) &&
1899            "unexpected this return");
1900     F->addAttribute(1, llvm::Attribute::Returned);
1901   }
1902 
1903   // Only a few attributes are set on declarations; these may later be
1904   // overridden by a definition.
1905 
1906   setLinkageForGV(F, FD);
1907   setGVProperties(F, FD);
1908 
1909   // Setup target-specific attributes.
1910   if (!IsIncompleteFunction && F->isDeclaration())
1911     getTargetCodeGenInfo().setTargetAttributes(FD, F, *this);
1912 
1913   if (const auto *CSA = FD->getAttr<CodeSegAttr>())
1914     F->setSection(CSA->getName());
1915   else if (const auto *SA = FD->getAttr<SectionAttr>())
1916      F->setSection(SA->getName());
1917 
1918   // If we plan on emitting this inline builtin, we can't treat it as a builtin.
1919   if (FD->isInlineBuiltinDeclaration()) {
1920     const FunctionDecl *FDBody;
1921     bool HasBody = FD->hasBody(FDBody);
1922     (void)HasBody;
1923     assert(HasBody && "Inline builtin declarations should always have an "
1924                       "available body!");
1925     if (shouldEmitFunction(FDBody))
1926       F->addAttribute(llvm::AttributeList::FunctionIndex,
1927                       llvm::Attribute::NoBuiltin);
1928   }
1929 
1930   if (FD->isReplaceableGlobalAllocationFunction()) {
1931     // A replaceable global allocation function does not act like a builtin by
1932     // default, only if it is invoked by a new-expression or delete-expression.
1933     F->addAttribute(llvm::AttributeList::FunctionIndex,
1934                     llvm::Attribute::NoBuiltin);
1935   }
1936 
1937   if (isa<CXXConstructorDecl>(FD) || isa<CXXDestructorDecl>(FD))
1938     F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1939   else if (const auto *MD = dyn_cast<CXXMethodDecl>(FD))
1940     if (MD->isVirtual())
1941       F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
1942 
1943   // Don't emit entries for function declarations in the cross-DSO mode. This
1944   // is handled with better precision by the receiving DSO. But if jump tables
1945   // are non-canonical then we need type metadata in order to produce the local
1946   // jump table.
1947   if (!CodeGenOpts.SanitizeCfiCrossDso ||
1948       !CodeGenOpts.SanitizeCfiCanonicalJumpTables)
1949     CreateFunctionTypeMetadataForIcall(FD, F);
1950 
1951   if (getLangOpts().OpenMP && FD->hasAttr<OMPDeclareSimdDeclAttr>())
1952     getOpenMPRuntime().emitDeclareSimdFunction(FD, F);
1953 
1954   if (const auto *CB = FD->getAttr<CallbackAttr>()) {
1955     // Annotate the callback behavior as metadata:
1956     //  - The callback callee (as argument number).
1957     //  - The callback payloads (as argument numbers).
1958     llvm::LLVMContext &Ctx = F->getContext();
1959     llvm::MDBuilder MDB(Ctx);
1960 
1961     // The payload indices are all but the first one in the encoding. The first
1962     // identifies the callback callee.
1963     int CalleeIdx = *CB->encoding_begin();
1964     ArrayRef<int> PayloadIndices(CB->encoding_begin() + 1, CB->encoding_end());
1965     F->addMetadata(llvm::LLVMContext::MD_callback,
1966                    *llvm::MDNode::get(Ctx, {MDB.createCallbackEncoding(
1967                                                CalleeIdx, PayloadIndices,
1968                                                /* VarArgsArePassed */ false)}));
1969   }
1970 }
1971 
1972 void CodeGenModule::addUsedGlobal(llvm::GlobalValue *GV) {
1973   assert(!GV->isDeclaration() &&
1974          "Only globals with definition can force usage.");
1975   LLVMUsed.emplace_back(GV);
1976 }
1977 
1978 void CodeGenModule::addCompilerUsedGlobal(llvm::GlobalValue *GV) {
1979   assert(!GV->isDeclaration() &&
1980          "Only globals with definition can force usage.");
1981   LLVMCompilerUsed.emplace_back(GV);
1982 }
1983 
1984 static void emitUsed(CodeGenModule &CGM, StringRef Name,
1985                      std::vector<llvm::WeakTrackingVH> &List) {
1986   // Don't create llvm.used if there is no need.
1987   if (List.empty())
1988     return;
1989 
1990   // Convert List to what ConstantArray needs.
1991   SmallVector<llvm::Constant*, 8> UsedArray;
1992   UsedArray.resize(List.size());
1993   for (unsigned i = 0, e = List.size(); i != e; ++i) {
1994     UsedArray[i] =
1995         llvm::ConstantExpr::getPointerBitCastOrAddrSpaceCast(
1996             cast<llvm::Constant>(&*List[i]), CGM.Int8PtrTy);
1997   }
1998 
1999   if (UsedArray.empty())
2000     return;
2001   llvm::ArrayType *ATy = llvm::ArrayType::get(CGM.Int8PtrTy, UsedArray.size());
2002 
2003   auto *GV = new llvm::GlobalVariable(
2004       CGM.getModule(), ATy, false, llvm::GlobalValue::AppendingLinkage,
2005       llvm::ConstantArray::get(ATy, UsedArray), Name);
2006 
2007   GV->setSection("llvm.metadata");
2008 }
2009 
2010 void CodeGenModule::emitLLVMUsed() {
2011   emitUsed(*this, "llvm.used", LLVMUsed);
2012   emitUsed(*this, "llvm.compiler.used", LLVMCompilerUsed);
2013 }
2014 
2015 void CodeGenModule::AppendLinkerOptions(StringRef Opts) {
2016   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opts);
2017   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2018 }
2019 
2020 void CodeGenModule::AddDetectMismatch(StringRef Name, StringRef Value) {
2021   llvm::SmallString<32> Opt;
2022   getTargetCodeGenInfo().getDetectMismatchOption(Name, Value, Opt);
2023   if (Opt.empty())
2024     return;
2025   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2026   LinkerOptionsMetadata.push_back(llvm::MDNode::get(getLLVMContext(), MDOpts));
2027 }
2028 
2029 void CodeGenModule::AddDependentLib(StringRef Lib) {
2030   auto &C = getLLVMContext();
2031   if (getTarget().getTriple().isOSBinFormatELF()) {
2032       ELFDependentLibraries.push_back(
2033         llvm::MDNode::get(C, llvm::MDString::get(C, Lib)));
2034     return;
2035   }
2036 
2037   llvm::SmallString<24> Opt;
2038   getTargetCodeGenInfo().getDependentLibraryOption(Lib, Opt);
2039   auto *MDOpts = llvm::MDString::get(getLLVMContext(), Opt);
2040   LinkerOptionsMetadata.push_back(llvm::MDNode::get(C, MDOpts));
2041 }
2042 
2043 /// Add link options implied by the given module, including modules
2044 /// it depends on, using a postorder walk.
2045 static void addLinkOptionsPostorder(CodeGenModule &CGM, Module *Mod,
2046                                     SmallVectorImpl<llvm::MDNode *> &Metadata,
2047                                     llvm::SmallPtrSet<Module *, 16> &Visited) {
2048   // Import this module's parent.
2049   if (Mod->Parent && Visited.insert(Mod->Parent).second) {
2050     addLinkOptionsPostorder(CGM, Mod->Parent, Metadata, Visited);
2051   }
2052 
2053   // Import this module's dependencies.
2054   for (unsigned I = Mod->Imports.size(); I > 0; --I) {
2055     if (Visited.insert(Mod->Imports[I - 1]).second)
2056       addLinkOptionsPostorder(CGM, Mod->Imports[I-1], Metadata, Visited);
2057   }
2058 
2059   // Add linker options to link against the libraries/frameworks
2060   // described by this module.
2061   llvm::LLVMContext &Context = CGM.getLLVMContext();
2062   bool IsELF = CGM.getTarget().getTriple().isOSBinFormatELF();
2063 
2064   // For modules that use export_as for linking, use that module
2065   // name instead.
2066   if (Mod->UseExportAsModuleLinkName)
2067     return;
2068 
2069   for (unsigned I = Mod->LinkLibraries.size(); I > 0; --I) {
2070     // Link against a framework.  Frameworks are currently Darwin only, so we
2071     // don't to ask TargetCodeGenInfo for the spelling of the linker option.
2072     if (Mod->LinkLibraries[I-1].IsFramework) {
2073       llvm::Metadata *Args[2] = {
2074           llvm::MDString::get(Context, "-framework"),
2075           llvm::MDString::get(Context, Mod->LinkLibraries[I - 1].Library)};
2076 
2077       Metadata.push_back(llvm::MDNode::get(Context, Args));
2078       continue;
2079     }
2080 
2081     // Link against a library.
2082     if (IsELF) {
2083       llvm::Metadata *Args[2] = {
2084           llvm::MDString::get(Context, "lib"),
2085           llvm::MDString::get(Context, Mod->LinkLibraries[I - 1].Library),
2086       };
2087       Metadata.push_back(llvm::MDNode::get(Context, Args));
2088     } else {
2089       llvm::SmallString<24> Opt;
2090       CGM.getTargetCodeGenInfo().getDependentLibraryOption(
2091           Mod->LinkLibraries[I - 1].Library, Opt);
2092       auto *OptString = llvm::MDString::get(Context, Opt);
2093       Metadata.push_back(llvm::MDNode::get(Context, OptString));
2094     }
2095   }
2096 }
2097 
2098 void CodeGenModule::EmitModuleLinkOptions() {
2099   // Collect the set of all of the modules we want to visit to emit link
2100   // options, which is essentially the imported modules and all of their
2101   // non-explicit child modules.
2102   llvm::SetVector<clang::Module *> LinkModules;
2103   llvm::SmallPtrSet<clang::Module *, 16> Visited;
2104   SmallVector<clang::Module *, 16> Stack;
2105 
2106   // Seed the stack with imported modules.
2107   for (Module *M : ImportedModules) {
2108     // Do not add any link flags when an implementation TU of a module imports
2109     // a header of that same module.
2110     if (M->getTopLevelModuleName() == getLangOpts().CurrentModule &&
2111         !getLangOpts().isCompilingModule())
2112       continue;
2113     if (Visited.insert(M).second)
2114       Stack.push_back(M);
2115   }
2116 
2117   // Find all of the modules to import, making a little effort to prune
2118   // non-leaf modules.
2119   while (!Stack.empty()) {
2120     clang::Module *Mod = Stack.pop_back_val();
2121 
2122     bool AnyChildren = false;
2123 
2124     // Visit the submodules of this module.
2125     for (const auto &SM : Mod->submodules()) {
2126       // Skip explicit children; they need to be explicitly imported to be
2127       // linked against.
2128       if (SM->IsExplicit)
2129         continue;
2130 
2131       if (Visited.insert(SM).second) {
2132         Stack.push_back(SM);
2133         AnyChildren = true;
2134       }
2135     }
2136 
2137     // We didn't find any children, so add this module to the list of
2138     // modules to link against.
2139     if (!AnyChildren) {
2140       LinkModules.insert(Mod);
2141     }
2142   }
2143 
2144   // Add link options for all of the imported modules in reverse topological
2145   // order.  We don't do anything to try to order import link flags with respect
2146   // to linker options inserted by things like #pragma comment().
2147   SmallVector<llvm::MDNode *, 16> MetadataArgs;
2148   Visited.clear();
2149   for (Module *M : LinkModules)
2150     if (Visited.insert(M).second)
2151       addLinkOptionsPostorder(*this, M, MetadataArgs, Visited);
2152   std::reverse(MetadataArgs.begin(), MetadataArgs.end());
2153   LinkerOptionsMetadata.append(MetadataArgs.begin(), MetadataArgs.end());
2154 
2155   // Add the linker options metadata flag.
2156   auto *NMD = getModule().getOrInsertNamedMetadata("llvm.linker.options");
2157   for (auto *MD : LinkerOptionsMetadata)
2158     NMD->addOperand(MD);
2159 }
2160 
2161 void CodeGenModule::EmitDeferred() {
2162   // Emit deferred declare target declarations.
2163   if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd)
2164     getOpenMPRuntime().emitDeferredTargetDecls();
2165 
2166   // Emit code for any potentially referenced deferred decls.  Since a
2167   // previously unused static decl may become used during the generation of code
2168   // for a static function, iterate until no changes are made.
2169 
2170   if (!DeferredVTables.empty()) {
2171     EmitDeferredVTables();
2172 
2173     // Emitting a vtable doesn't directly cause more vtables to
2174     // become deferred, although it can cause functions to be
2175     // emitted that then need those vtables.
2176     assert(DeferredVTables.empty());
2177   }
2178 
2179   // Stop if we're out of both deferred vtables and deferred declarations.
2180   if (DeferredDeclsToEmit.empty())
2181     return;
2182 
2183   // Grab the list of decls to emit. If EmitGlobalDefinition schedules more
2184   // work, it will not interfere with this.
2185   std::vector<GlobalDecl> CurDeclsToEmit;
2186   CurDeclsToEmit.swap(DeferredDeclsToEmit);
2187 
2188   for (GlobalDecl &D : CurDeclsToEmit) {
2189     // We should call GetAddrOfGlobal with IsForDefinition set to true in order
2190     // to get GlobalValue with exactly the type we need, not something that
2191     // might had been created for another decl with the same mangled name but
2192     // different type.
2193     llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(
2194         GetAddrOfGlobal(D, ForDefinition));
2195 
2196     // In case of different address spaces, we may still get a cast, even with
2197     // IsForDefinition equal to true. Query mangled names table to get
2198     // GlobalValue.
2199     if (!GV)
2200       GV = GetGlobalValue(getMangledName(D));
2201 
2202     // Make sure GetGlobalValue returned non-null.
2203     assert(GV);
2204 
2205     // Check to see if we've already emitted this.  This is necessary
2206     // for a couple of reasons: first, decls can end up in the
2207     // deferred-decls queue multiple times, and second, decls can end
2208     // up with definitions in unusual ways (e.g. by an extern inline
2209     // function acquiring a strong function redefinition).  Just
2210     // ignore these cases.
2211     if (!GV->isDeclaration())
2212       continue;
2213 
2214     // If this is OpenMP, check if it is legal to emit this global normally.
2215     if (LangOpts.OpenMP && OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(D))
2216       continue;
2217 
2218     // Otherwise, emit the definition and move on to the next one.
2219     EmitGlobalDefinition(D, GV);
2220 
2221     // If we found out that we need to emit more decls, do that recursively.
2222     // This has the advantage that the decls are emitted in a DFS and related
2223     // ones are close together, which is convenient for testing.
2224     if (!DeferredVTables.empty() || !DeferredDeclsToEmit.empty()) {
2225       EmitDeferred();
2226       assert(DeferredVTables.empty() && DeferredDeclsToEmit.empty());
2227     }
2228   }
2229 }
2230 
2231 void CodeGenModule::EmitVTablesOpportunistically() {
2232   // Try to emit external vtables as available_externally if they have emitted
2233   // all inlined virtual functions.  It runs after EmitDeferred() and therefore
2234   // is not allowed to create new references to things that need to be emitted
2235   // lazily. Note that it also uses fact that we eagerly emitting RTTI.
2236 
2237   assert((OpportunisticVTables.empty() || shouldOpportunisticallyEmitVTables())
2238          && "Only emit opportunistic vtables with optimizations");
2239 
2240   for (const CXXRecordDecl *RD : OpportunisticVTables) {
2241     assert(getVTables().isVTableExternal(RD) &&
2242            "This queue should only contain external vtables");
2243     if (getCXXABI().canSpeculativelyEmitVTable(RD))
2244       VTables.GenerateClassData(RD);
2245   }
2246   OpportunisticVTables.clear();
2247 }
2248 
2249 void CodeGenModule::EmitGlobalAnnotations() {
2250   if (Annotations.empty())
2251     return;
2252 
2253   // Create a new global variable for the ConstantStruct in the Module.
2254   llvm::Constant *Array = llvm::ConstantArray::get(llvm::ArrayType::get(
2255     Annotations[0]->getType(), Annotations.size()), Annotations);
2256   auto *gv = new llvm::GlobalVariable(getModule(), Array->getType(), false,
2257                                       llvm::GlobalValue::AppendingLinkage,
2258                                       Array, "llvm.global.annotations");
2259   gv->setSection(AnnotationSection);
2260 }
2261 
2262 llvm::Constant *CodeGenModule::EmitAnnotationString(StringRef Str) {
2263   llvm::Constant *&AStr = AnnotationStrings[Str];
2264   if (AStr)
2265     return AStr;
2266 
2267   // Not found yet, create a new global.
2268   llvm::Constant *s = llvm::ConstantDataArray::getString(getLLVMContext(), Str);
2269   auto *gv =
2270       new llvm::GlobalVariable(getModule(), s->getType(), true,
2271                                llvm::GlobalValue::PrivateLinkage, s, ".str");
2272   gv->setSection(AnnotationSection);
2273   gv->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
2274   AStr = gv;
2275   return gv;
2276 }
2277 
2278 llvm::Constant *CodeGenModule::EmitAnnotationUnit(SourceLocation Loc) {
2279   SourceManager &SM = getContext().getSourceManager();
2280   PresumedLoc PLoc = SM.getPresumedLoc(Loc);
2281   if (PLoc.isValid())
2282     return EmitAnnotationString(PLoc.getFilename());
2283   return EmitAnnotationString(SM.getBufferName(Loc));
2284 }
2285 
2286 llvm::Constant *CodeGenModule::EmitAnnotationLineNo(SourceLocation L) {
2287   SourceManager &SM = getContext().getSourceManager();
2288   PresumedLoc PLoc = SM.getPresumedLoc(L);
2289   unsigned LineNo = PLoc.isValid() ? PLoc.getLine() :
2290     SM.getExpansionLineNumber(L);
2291   return llvm::ConstantInt::get(Int32Ty, LineNo);
2292 }
2293 
2294 llvm::Constant *CodeGenModule::EmitAnnotateAttr(llvm::GlobalValue *GV,
2295                                                 const AnnotateAttr *AA,
2296                                                 SourceLocation L) {
2297   // Get the globals for file name, annotation, and the line number.
2298   llvm::Constant *AnnoGV = EmitAnnotationString(AA->getAnnotation()),
2299                  *UnitGV = EmitAnnotationUnit(L),
2300                  *LineNoCst = EmitAnnotationLineNo(L);
2301 
2302   llvm::Constant *ASZeroGV = GV;
2303   if (GV->getAddressSpace() != 0) {
2304     ASZeroGV = llvm::ConstantExpr::getAddrSpaceCast(
2305                    GV, GV->getValueType()->getPointerTo(0));
2306   }
2307 
2308   // Create the ConstantStruct for the global annotation.
2309   llvm::Constant *Fields[4] = {
2310     llvm::ConstantExpr::getBitCast(ASZeroGV, Int8PtrTy),
2311     llvm::ConstantExpr::getBitCast(AnnoGV, Int8PtrTy),
2312     llvm::ConstantExpr::getBitCast(UnitGV, Int8PtrTy),
2313     LineNoCst
2314   };
2315   return llvm::ConstantStruct::getAnon(Fields);
2316 }
2317 
2318 void CodeGenModule::AddGlobalAnnotations(const ValueDecl *D,
2319                                          llvm::GlobalValue *GV) {
2320   assert(D->hasAttr<AnnotateAttr>() && "no annotate attribute");
2321   // Get the struct elements for these annotations.
2322   for (const auto *I : D->specific_attrs<AnnotateAttr>())
2323     Annotations.push_back(EmitAnnotateAttr(GV, I, D->getLocation()));
2324 }
2325 
2326 bool CodeGenModule::isInSanitizerBlacklist(SanitizerMask Kind,
2327                                            llvm::Function *Fn,
2328                                            SourceLocation Loc) const {
2329   const auto &SanitizerBL = getContext().getSanitizerBlacklist();
2330   // Blacklist by function name.
2331   if (SanitizerBL.isBlacklistedFunction(Kind, Fn->getName()))
2332     return true;
2333   // Blacklist by location.
2334   if (Loc.isValid())
2335     return SanitizerBL.isBlacklistedLocation(Kind, Loc);
2336   // If location is unknown, this may be a compiler-generated function. Assume
2337   // it's located in the main file.
2338   auto &SM = Context.getSourceManager();
2339   if (const auto *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
2340     return SanitizerBL.isBlacklistedFile(Kind, MainFile->getName());
2341   }
2342   return false;
2343 }
2344 
2345 bool CodeGenModule::isInSanitizerBlacklist(llvm::GlobalVariable *GV,
2346                                            SourceLocation Loc, QualType Ty,
2347                                            StringRef Category) const {
2348   // For now globals can be blacklisted only in ASan and KASan.
2349   const SanitizerMask EnabledAsanMask =
2350       LangOpts.Sanitize.Mask &
2351       (SanitizerKind::Address | SanitizerKind::KernelAddress |
2352        SanitizerKind::HWAddress | SanitizerKind::KernelHWAddress |
2353        SanitizerKind::MemTag);
2354   if (!EnabledAsanMask)
2355     return false;
2356   const auto &SanitizerBL = getContext().getSanitizerBlacklist();
2357   if (SanitizerBL.isBlacklistedGlobal(EnabledAsanMask, GV->getName(), Category))
2358     return true;
2359   if (SanitizerBL.isBlacklistedLocation(EnabledAsanMask, Loc, Category))
2360     return true;
2361   // Check global type.
2362   if (!Ty.isNull()) {
2363     // Drill down the array types: if global variable of a fixed type is
2364     // blacklisted, we also don't instrument arrays of them.
2365     while (auto AT = dyn_cast<ArrayType>(Ty.getTypePtr()))
2366       Ty = AT->getElementType();
2367     Ty = Ty.getCanonicalType().getUnqualifiedType();
2368     // We allow to blacklist only record types (classes, structs etc.)
2369     if (Ty->isRecordType()) {
2370       std::string TypeStr = Ty.getAsString(getContext().getPrintingPolicy());
2371       if (SanitizerBL.isBlacklistedType(EnabledAsanMask, TypeStr, Category))
2372         return true;
2373     }
2374   }
2375   return false;
2376 }
2377 
2378 bool CodeGenModule::imbueXRayAttrs(llvm::Function *Fn, SourceLocation Loc,
2379                                    StringRef Category) const {
2380   const auto &XRayFilter = getContext().getXRayFilter();
2381   using ImbueAttr = XRayFunctionFilter::ImbueAttribute;
2382   auto Attr = ImbueAttr::NONE;
2383   if (Loc.isValid())
2384     Attr = XRayFilter.shouldImbueLocation(Loc, Category);
2385   if (Attr == ImbueAttr::NONE)
2386     Attr = XRayFilter.shouldImbueFunction(Fn->getName());
2387   switch (Attr) {
2388   case ImbueAttr::NONE:
2389     return false;
2390   case ImbueAttr::ALWAYS:
2391     Fn->addFnAttr("function-instrument", "xray-always");
2392     break;
2393   case ImbueAttr::ALWAYS_ARG1:
2394     Fn->addFnAttr("function-instrument", "xray-always");
2395     Fn->addFnAttr("xray-log-args", "1");
2396     break;
2397   case ImbueAttr::NEVER:
2398     Fn->addFnAttr("function-instrument", "xray-never");
2399     break;
2400   }
2401   return true;
2402 }
2403 
2404 bool CodeGenModule::MustBeEmitted(const ValueDecl *Global) {
2405   // Never defer when EmitAllDecls is specified.
2406   if (LangOpts.EmitAllDecls)
2407     return true;
2408 
2409   if (CodeGenOpts.KeepStaticConsts) {
2410     const auto *VD = dyn_cast<VarDecl>(Global);
2411     if (VD && VD->getType().isConstQualified() &&
2412         VD->getStorageDuration() == SD_Static)
2413       return true;
2414   }
2415 
2416   return getContext().DeclMustBeEmitted(Global);
2417 }
2418 
2419 bool CodeGenModule::MayBeEmittedEagerly(const ValueDecl *Global) {
2420   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
2421     if (FD->getTemplateSpecializationKind() == TSK_ImplicitInstantiation)
2422       // Implicit template instantiations may change linkage if they are later
2423       // explicitly instantiated, so they should not be emitted eagerly.
2424       return false;
2425     // In OpenMP 5.0 function may be marked as device_type(nohost) and we should
2426     // not emit them eagerly unless we sure that the function must be emitted on
2427     // the host.
2428     if (LangOpts.OpenMP >= 50 && !LangOpts.OpenMPSimd &&
2429         !LangOpts.OpenMPIsDevice &&
2430         !OMPDeclareTargetDeclAttr::getDeviceType(FD) &&
2431         !FD->isUsed(/*CheckUsedAttr=*/false) && !FD->isReferenced())
2432       return false;
2433   }
2434   if (const auto *VD = dyn_cast<VarDecl>(Global))
2435     if (Context.getInlineVariableDefinitionKind(VD) ==
2436         ASTContext::InlineVariableDefinitionKind::WeakUnknown)
2437       // A definition of an inline constexpr static data member may change
2438       // linkage later if it's redeclared outside the class.
2439       return false;
2440   // If OpenMP is enabled and threadprivates must be generated like TLS, delay
2441   // codegen for global variables, because they may be marked as threadprivate.
2442   if (LangOpts.OpenMP && LangOpts.OpenMPUseTLS &&
2443       getContext().getTargetInfo().isTLSSupported() && isa<VarDecl>(Global) &&
2444       !isTypeConstant(Global->getType(), false) &&
2445       !OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(Global))
2446     return false;
2447 
2448   return true;
2449 }
2450 
2451 ConstantAddress CodeGenModule::GetAddrOfMSGuidDecl(const MSGuidDecl *GD) {
2452   StringRef Name = getMangledName(GD);
2453 
2454   // The UUID descriptor should be pointer aligned.
2455   CharUnits Alignment = CharUnits::fromQuantity(PointerAlignInBytes);
2456 
2457   // Look for an existing global.
2458   if (llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name))
2459     return ConstantAddress(GV, Alignment);
2460 
2461   ConstantEmitter Emitter(*this);
2462   llvm::Constant *Init;
2463 
2464   APValue &V = GD->getAsAPValue();
2465   if (!V.isAbsent()) {
2466     // If possible, emit the APValue version of the initializer. In particular,
2467     // this gets the type of the constant right.
2468     Init = Emitter.emitForInitializer(
2469         GD->getAsAPValue(), GD->getType().getAddressSpace(), GD->getType());
2470   } else {
2471     // As a fallback, directly construct the constant.
2472     // FIXME: This may get padding wrong under esoteric struct layout rules.
2473     // MSVC appears to create a complete type 'struct __s_GUID' that it
2474     // presumably uses to represent these constants.
2475     MSGuidDecl::Parts Parts = GD->getParts();
2476     llvm::Constant *Fields[4] = {
2477         llvm::ConstantInt::get(Int32Ty, Parts.Part1),
2478         llvm::ConstantInt::get(Int16Ty, Parts.Part2),
2479         llvm::ConstantInt::get(Int16Ty, Parts.Part3),
2480         llvm::ConstantDataArray::getRaw(
2481             StringRef(reinterpret_cast<char *>(Parts.Part4And5), 8), 8,
2482             Int8Ty)};
2483     Init = llvm::ConstantStruct::getAnon(Fields);
2484   }
2485 
2486   auto *GV = new llvm::GlobalVariable(
2487       getModule(), Init->getType(),
2488       /*isConstant=*/true, llvm::GlobalValue::LinkOnceODRLinkage, Init, Name);
2489   if (supportsCOMDAT())
2490     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
2491   setDSOLocal(GV);
2492 
2493   llvm::Constant *Addr = GV;
2494   if (!V.isAbsent()) {
2495     Emitter.finalize(GV);
2496   } else {
2497     llvm::Type *Ty = getTypes().ConvertTypeForMem(GD->getType());
2498     Addr = llvm::ConstantExpr::getBitCast(
2499         GV, Ty->getPointerTo(GV->getAddressSpace()));
2500   }
2501   return ConstantAddress(Addr, Alignment);
2502 }
2503 
2504 ConstantAddress CodeGenModule::GetWeakRefReference(const ValueDecl *VD) {
2505   const AliasAttr *AA = VD->getAttr<AliasAttr>();
2506   assert(AA && "No alias?");
2507 
2508   CharUnits Alignment = getContext().getDeclAlign(VD);
2509   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(VD->getType());
2510 
2511   // See if there is already something with the target's name in the module.
2512   llvm::GlobalValue *Entry = GetGlobalValue(AA->getAliasee());
2513   if (Entry) {
2514     unsigned AS = getContext().getTargetAddressSpace(VD->getType());
2515     auto Ptr = llvm::ConstantExpr::getBitCast(Entry, DeclTy->getPointerTo(AS));
2516     return ConstantAddress(Ptr, Alignment);
2517   }
2518 
2519   llvm::Constant *Aliasee;
2520   if (isa<llvm::FunctionType>(DeclTy))
2521     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy,
2522                                       GlobalDecl(cast<FunctionDecl>(VD)),
2523                                       /*ForVTable=*/false);
2524   else
2525     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
2526                                     llvm::PointerType::getUnqual(DeclTy),
2527                                     nullptr);
2528 
2529   auto *F = cast<llvm::GlobalValue>(Aliasee);
2530   F->setLinkage(llvm::Function::ExternalWeakLinkage);
2531   WeakRefReferences.insert(F);
2532 
2533   return ConstantAddress(Aliasee, Alignment);
2534 }
2535 
2536 void CodeGenModule::EmitGlobal(GlobalDecl GD) {
2537   const auto *Global = cast<ValueDecl>(GD.getDecl());
2538 
2539   // Weak references don't produce any output by themselves.
2540   if (Global->hasAttr<WeakRefAttr>())
2541     return;
2542 
2543   // If this is an alias definition (which otherwise looks like a declaration)
2544   // emit it now.
2545   if (Global->hasAttr<AliasAttr>())
2546     return EmitAliasDefinition(GD);
2547 
2548   // IFunc like an alias whose value is resolved at runtime by calling resolver.
2549   if (Global->hasAttr<IFuncAttr>())
2550     return emitIFuncDefinition(GD);
2551 
2552   // If this is a cpu_dispatch multiversion function, emit the resolver.
2553   if (Global->hasAttr<CPUDispatchAttr>())
2554     return emitCPUDispatchDefinition(GD);
2555 
2556   // If this is CUDA, be selective about which declarations we emit.
2557   if (LangOpts.CUDA) {
2558     if (LangOpts.CUDAIsDevice) {
2559       if (!Global->hasAttr<CUDADeviceAttr>() &&
2560           !Global->hasAttr<CUDAGlobalAttr>() &&
2561           !Global->hasAttr<CUDAConstantAttr>() &&
2562           !Global->hasAttr<CUDASharedAttr>() &&
2563           !Global->getType()->isCUDADeviceBuiltinSurfaceType() &&
2564           !Global->getType()->isCUDADeviceBuiltinTextureType())
2565         return;
2566     } else {
2567       // We need to emit host-side 'shadows' for all global
2568       // device-side variables because the CUDA runtime needs their
2569       // size and host-side address in order to provide access to
2570       // their device-side incarnations.
2571 
2572       // So device-only functions are the only things we skip.
2573       if (isa<FunctionDecl>(Global) && !Global->hasAttr<CUDAHostAttr>() &&
2574           Global->hasAttr<CUDADeviceAttr>())
2575         return;
2576 
2577       assert((isa<FunctionDecl>(Global) || isa<VarDecl>(Global)) &&
2578              "Expected Variable or Function");
2579     }
2580   }
2581 
2582   if (LangOpts.OpenMP) {
2583     // If this is OpenMP, check if it is legal to emit this global normally.
2584     if (OpenMPRuntime && OpenMPRuntime->emitTargetGlobal(GD))
2585       return;
2586     if (auto *DRD = dyn_cast<OMPDeclareReductionDecl>(Global)) {
2587       if (MustBeEmitted(Global))
2588         EmitOMPDeclareReduction(DRD);
2589       return;
2590     } else if (auto *DMD = dyn_cast<OMPDeclareMapperDecl>(Global)) {
2591       if (MustBeEmitted(Global))
2592         EmitOMPDeclareMapper(DMD);
2593       return;
2594     }
2595   }
2596 
2597   // Ignore declarations, they will be emitted on their first use.
2598   if (const auto *FD = dyn_cast<FunctionDecl>(Global)) {
2599     // Forward declarations are emitted lazily on first use.
2600     if (!FD->doesThisDeclarationHaveABody()) {
2601       if (!FD->doesDeclarationForceExternallyVisibleDefinition())
2602         return;
2603 
2604       StringRef MangledName = getMangledName(GD);
2605 
2606       // Compute the function info and LLVM type.
2607       const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
2608       llvm::Type *Ty = getTypes().GetFunctionType(FI);
2609 
2610       GetOrCreateLLVMFunction(MangledName, Ty, GD, /*ForVTable=*/false,
2611                               /*DontDefer=*/false);
2612       return;
2613     }
2614   } else {
2615     const auto *VD = cast<VarDecl>(Global);
2616     assert(VD->isFileVarDecl() && "Cannot emit local var decl as global.");
2617     if (VD->isThisDeclarationADefinition() != VarDecl::Definition &&
2618         !Context.isMSStaticDataMemberInlineDefinition(VD)) {
2619       if (LangOpts.OpenMP) {
2620         // Emit declaration of the must-be-emitted declare target variable.
2621         if (llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
2622                 OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD)) {
2623           bool UnifiedMemoryEnabled =
2624               getOpenMPRuntime().hasRequiresUnifiedSharedMemory();
2625           if (*Res == OMPDeclareTargetDeclAttr::MT_To &&
2626               !UnifiedMemoryEnabled) {
2627             (void)GetAddrOfGlobalVar(VD);
2628           } else {
2629             assert(((*Res == OMPDeclareTargetDeclAttr::MT_Link) ||
2630                     (*Res == OMPDeclareTargetDeclAttr::MT_To &&
2631                      UnifiedMemoryEnabled)) &&
2632                    "Link clause or to clause with unified memory expected.");
2633             (void)getOpenMPRuntime().getAddrOfDeclareTargetVar(VD);
2634           }
2635 
2636           return;
2637         }
2638       }
2639       // If this declaration may have caused an inline variable definition to
2640       // change linkage, make sure that it's emitted.
2641       if (Context.getInlineVariableDefinitionKind(VD) ==
2642           ASTContext::InlineVariableDefinitionKind::Strong)
2643         GetAddrOfGlobalVar(VD);
2644       return;
2645     }
2646   }
2647 
2648   // Defer code generation to first use when possible, e.g. if this is an inline
2649   // function. If the global must always be emitted, do it eagerly if possible
2650   // to benefit from cache locality.
2651   if (MustBeEmitted(Global) && MayBeEmittedEagerly(Global)) {
2652     // Emit the definition if it can't be deferred.
2653     EmitGlobalDefinition(GD);
2654     return;
2655   }
2656 
2657   // If we're deferring emission of a C++ variable with an
2658   // initializer, remember the order in which it appeared in the file.
2659   if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) &&
2660       cast<VarDecl>(Global)->hasInit()) {
2661     DelayedCXXInitPosition[Global] = CXXGlobalInits.size();
2662     CXXGlobalInits.push_back(nullptr);
2663   }
2664 
2665   StringRef MangledName = getMangledName(GD);
2666   if (GetGlobalValue(MangledName) != nullptr) {
2667     // The value has already been used and should therefore be emitted.
2668     addDeferredDeclToEmit(GD);
2669   } else if (MustBeEmitted(Global)) {
2670     // The value must be emitted, but cannot be emitted eagerly.
2671     assert(!MayBeEmittedEagerly(Global));
2672     addDeferredDeclToEmit(GD);
2673   } else {
2674     // Otherwise, remember that we saw a deferred decl with this name.  The
2675     // first use of the mangled name will cause it to move into
2676     // DeferredDeclsToEmit.
2677     DeferredDecls[MangledName] = GD;
2678   }
2679 }
2680 
2681 // Check if T is a class type with a destructor that's not dllimport.
2682 static bool HasNonDllImportDtor(QualType T) {
2683   if (const auto *RT = T->getBaseElementTypeUnsafe()->getAs<RecordType>())
2684     if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
2685       if (RD->getDestructor() && !RD->getDestructor()->hasAttr<DLLImportAttr>())
2686         return true;
2687 
2688   return false;
2689 }
2690 
2691 namespace {
2692   struct FunctionIsDirectlyRecursive
2693       : public ConstStmtVisitor<FunctionIsDirectlyRecursive, bool> {
2694     const StringRef Name;
2695     const Builtin::Context &BI;
2696     FunctionIsDirectlyRecursive(StringRef N, const Builtin::Context &C)
2697         : Name(N), BI(C) {}
2698 
2699     bool VisitCallExpr(const CallExpr *E) {
2700       const FunctionDecl *FD = E->getDirectCallee();
2701       if (!FD)
2702         return false;
2703       AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
2704       if (Attr && Name == Attr->getLabel())
2705         return true;
2706       unsigned BuiltinID = FD->getBuiltinID();
2707       if (!BuiltinID || !BI.isLibFunction(BuiltinID))
2708         return false;
2709       StringRef BuiltinName = BI.getName(BuiltinID);
2710       if (BuiltinName.startswith("__builtin_") &&
2711           Name == BuiltinName.slice(strlen("__builtin_"), StringRef::npos)) {
2712         return true;
2713       }
2714       return false;
2715     }
2716 
2717     bool VisitStmt(const Stmt *S) {
2718       for (const Stmt *Child : S->children())
2719         if (Child && this->Visit(Child))
2720           return true;
2721       return false;
2722     }
2723   };
2724 
2725   // Make sure we're not referencing non-imported vars or functions.
2726   struct DLLImportFunctionVisitor
2727       : public RecursiveASTVisitor<DLLImportFunctionVisitor> {
2728     bool SafeToInline = true;
2729 
2730     bool shouldVisitImplicitCode() const { return true; }
2731 
2732     bool VisitVarDecl(VarDecl *VD) {
2733       if (VD->getTLSKind()) {
2734         // A thread-local variable cannot be imported.
2735         SafeToInline = false;
2736         return SafeToInline;
2737       }
2738 
2739       // A variable definition might imply a destructor call.
2740       if (VD->isThisDeclarationADefinition())
2741         SafeToInline = !HasNonDllImportDtor(VD->getType());
2742 
2743       return SafeToInline;
2744     }
2745 
2746     bool VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
2747       if (const auto *D = E->getTemporary()->getDestructor())
2748         SafeToInline = D->hasAttr<DLLImportAttr>();
2749       return SafeToInline;
2750     }
2751 
2752     bool VisitDeclRefExpr(DeclRefExpr *E) {
2753       ValueDecl *VD = E->getDecl();
2754       if (isa<FunctionDecl>(VD))
2755         SafeToInline = VD->hasAttr<DLLImportAttr>();
2756       else if (VarDecl *V = dyn_cast<VarDecl>(VD))
2757         SafeToInline = !V->hasGlobalStorage() || V->hasAttr<DLLImportAttr>();
2758       return SafeToInline;
2759     }
2760 
2761     bool VisitCXXConstructExpr(CXXConstructExpr *E) {
2762       SafeToInline = E->getConstructor()->hasAttr<DLLImportAttr>();
2763       return SafeToInline;
2764     }
2765 
2766     bool VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
2767       CXXMethodDecl *M = E->getMethodDecl();
2768       if (!M) {
2769         // Call through a pointer to member function. This is safe to inline.
2770         SafeToInline = true;
2771       } else {
2772         SafeToInline = M->hasAttr<DLLImportAttr>();
2773       }
2774       return SafeToInline;
2775     }
2776 
2777     bool VisitCXXDeleteExpr(CXXDeleteExpr *E) {
2778       SafeToInline = E->getOperatorDelete()->hasAttr<DLLImportAttr>();
2779       return SafeToInline;
2780     }
2781 
2782     bool VisitCXXNewExpr(CXXNewExpr *E) {
2783       SafeToInline = E->getOperatorNew()->hasAttr<DLLImportAttr>();
2784       return SafeToInline;
2785     }
2786   };
2787 }
2788 
2789 // isTriviallyRecursive - Check if this function calls another
2790 // decl that, because of the asm attribute or the other decl being a builtin,
2791 // ends up pointing to itself.
2792 bool
2793 CodeGenModule::isTriviallyRecursive(const FunctionDecl *FD) {
2794   StringRef Name;
2795   if (getCXXABI().getMangleContext().shouldMangleDeclName(FD)) {
2796     // asm labels are a special kind of mangling we have to support.
2797     AsmLabelAttr *Attr = FD->getAttr<AsmLabelAttr>();
2798     if (!Attr)
2799       return false;
2800     Name = Attr->getLabel();
2801   } else {
2802     Name = FD->getName();
2803   }
2804 
2805   FunctionIsDirectlyRecursive Walker(Name, Context.BuiltinInfo);
2806   const Stmt *Body = FD->getBody();
2807   return Body ? Walker.Visit(Body) : false;
2808 }
2809 
2810 bool CodeGenModule::shouldEmitFunction(GlobalDecl GD) {
2811   if (getFunctionLinkage(GD) != llvm::Function::AvailableExternallyLinkage)
2812     return true;
2813   const auto *F = cast<FunctionDecl>(GD.getDecl());
2814   if (CodeGenOpts.OptimizationLevel == 0 && !F->hasAttr<AlwaysInlineAttr>())
2815     return false;
2816 
2817   if (F->hasAttr<DLLImportAttr>()) {
2818     // Check whether it would be safe to inline this dllimport function.
2819     DLLImportFunctionVisitor Visitor;
2820     Visitor.TraverseFunctionDecl(const_cast<FunctionDecl*>(F));
2821     if (!Visitor.SafeToInline)
2822       return false;
2823 
2824     if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(F)) {
2825       // Implicit destructor invocations aren't captured in the AST, so the
2826       // check above can't see them. Check for them manually here.
2827       for (const Decl *Member : Dtor->getParent()->decls())
2828         if (isa<FieldDecl>(Member))
2829           if (HasNonDllImportDtor(cast<FieldDecl>(Member)->getType()))
2830             return false;
2831       for (const CXXBaseSpecifier &B : Dtor->getParent()->bases())
2832         if (HasNonDllImportDtor(B.getType()))
2833           return false;
2834     }
2835   }
2836 
2837   // PR9614. Avoid cases where the source code is lying to us. An available
2838   // externally function should have an equivalent function somewhere else,
2839   // but a function that calls itself through asm label/`__builtin_` trickery is
2840   // clearly not equivalent to the real implementation.
2841   // This happens in glibc's btowc and in some configure checks.
2842   return !isTriviallyRecursive(F);
2843 }
2844 
2845 bool CodeGenModule::shouldOpportunisticallyEmitVTables() {
2846   return CodeGenOpts.OptimizationLevel > 0;
2847 }
2848 
2849 void CodeGenModule::EmitMultiVersionFunctionDefinition(GlobalDecl GD,
2850                                                        llvm::GlobalValue *GV) {
2851   const auto *FD = cast<FunctionDecl>(GD.getDecl());
2852 
2853   if (FD->isCPUSpecificMultiVersion()) {
2854     auto *Spec = FD->getAttr<CPUSpecificAttr>();
2855     for (unsigned I = 0; I < Spec->cpus_size(); ++I)
2856       EmitGlobalFunctionDefinition(GD.getWithMultiVersionIndex(I), nullptr);
2857     // Requires multiple emits.
2858   } else
2859     EmitGlobalFunctionDefinition(GD, GV);
2860 }
2861 
2862 void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
2863   const auto *D = cast<ValueDecl>(GD.getDecl());
2864 
2865   PrettyStackTraceDecl CrashInfo(const_cast<ValueDecl *>(D), D->getLocation(),
2866                                  Context.getSourceManager(),
2867                                  "Generating code for declaration");
2868 
2869   if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
2870     // At -O0, don't generate IR for functions with available_externally
2871     // linkage.
2872     if (!shouldEmitFunction(GD))
2873       return;
2874 
2875     llvm::TimeTraceScope TimeScope("CodeGen Function", [&]() {
2876       std::string Name;
2877       llvm::raw_string_ostream OS(Name);
2878       FD->getNameForDiagnostic(OS, getContext().getPrintingPolicy(),
2879                                /*Qualified=*/true);
2880       return Name;
2881     });
2882 
2883     if (const auto *Method = dyn_cast<CXXMethodDecl>(D)) {
2884       // Make sure to emit the definition(s) before we emit the thunks.
2885       // This is necessary for the generation of certain thunks.
2886       if (isa<CXXConstructorDecl>(Method) || isa<CXXDestructorDecl>(Method))
2887         ABI->emitCXXStructor(GD);
2888       else if (FD->isMultiVersion())
2889         EmitMultiVersionFunctionDefinition(GD, GV);
2890       else
2891         EmitGlobalFunctionDefinition(GD, GV);
2892 
2893       if (Method->isVirtual())
2894         getVTables().EmitThunks(GD);
2895 
2896       return;
2897     }
2898 
2899     if (FD->isMultiVersion())
2900       return EmitMultiVersionFunctionDefinition(GD, GV);
2901     return EmitGlobalFunctionDefinition(GD, GV);
2902   }
2903 
2904   if (const auto *VD = dyn_cast<VarDecl>(D))
2905     return EmitGlobalVarDefinition(VD, !VD->hasDefinition());
2906 
2907   llvm_unreachable("Invalid argument to EmitGlobalDefinition()");
2908 }
2909 
2910 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
2911                                                       llvm::Function *NewFn);
2912 
2913 static unsigned
2914 TargetMVPriority(const TargetInfo &TI,
2915                  const CodeGenFunction::MultiVersionResolverOption &RO) {
2916   unsigned Priority = 0;
2917   for (StringRef Feat : RO.Conditions.Features)
2918     Priority = std::max(Priority, TI.multiVersionSortPriority(Feat));
2919 
2920   if (!RO.Conditions.Architecture.empty())
2921     Priority = std::max(
2922         Priority, TI.multiVersionSortPriority(RO.Conditions.Architecture));
2923   return Priority;
2924 }
2925 
2926 void CodeGenModule::emitMultiVersionFunctions() {
2927   for (GlobalDecl GD : MultiVersionFuncs) {
2928     SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
2929     const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
2930     getContext().forEachMultiversionedFunctionVersion(
2931         FD, [this, &GD, &Options](const FunctionDecl *CurFD) {
2932           GlobalDecl CurGD{
2933               (CurFD->isDefined() ? CurFD->getDefinition() : CurFD)};
2934           StringRef MangledName = getMangledName(CurGD);
2935           llvm::Constant *Func = GetGlobalValue(MangledName);
2936           if (!Func) {
2937             if (CurFD->isDefined()) {
2938               EmitGlobalFunctionDefinition(CurGD, nullptr);
2939               Func = GetGlobalValue(MangledName);
2940             } else {
2941               const CGFunctionInfo &FI =
2942                   getTypes().arrangeGlobalDeclaration(GD);
2943               llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
2944               Func = GetAddrOfFunction(CurGD, Ty, /*ForVTable=*/false,
2945                                        /*DontDefer=*/false, ForDefinition);
2946             }
2947             assert(Func && "This should have just been created");
2948           }
2949 
2950           const auto *TA = CurFD->getAttr<TargetAttr>();
2951           llvm::SmallVector<StringRef, 8> Feats;
2952           TA->getAddedFeatures(Feats);
2953 
2954           Options.emplace_back(cast<llvm::Function>(Func),
2955                                TA->getArchitecture(), Feats);
2956         });
2957 
2958     llvm::Function *ResolverFunc;
2959     const TargetInfo &TI = getTarget();
2960 
2961     if (TI.supportsIFunc() || FD->isTargetMultiVersion()) {
2962       ResolverFunc = cast<llvm::Function>(
2963           GetGlobalValue((getMangledName(GD) + ".resolver").str()));
2964       ResolverFunc->setLinkage(llvm::Function::WeakODRLinkage);
2965     } else {
2966       ResolverFunc = cast<llvm::Function>(GetGlobalValue(getMangledName(GD)));
2967     }
2968 
2969     if (supportsCOMDAT())
2970       ResolverFunc->setComdat(
2971           getModule().getOrInsertComdat(ResolverFunc->getName()));
2972 
2973     llvm::stable_sort(
2974         Options, [&TI](const CodeGenFunction::MultiVersionResolverOption &LHS,
2975                        const CodeGenFunction::MultiVersionResolverOption &RHS) {
2976           return TargetMVPriority(TI, LHS) > TargetMVPriority(TI, RHS);
2977         });
2978     CodeGenFunction CGF(*this);
2979     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
2980   }
2981 }
2982 
2983 void CodeGenModule::emitCPUDispatchDefinition(GlobalDecl GD) {
2984   const auto *FD = cast<FunctionDecl>(GD.getDecl());
2985   assert(FD && "Not a FunctionDecl?");
2986   const auto *DD = FD->getAttr<CPUDispatchAttr>();
2987   assert(DD && "Not a cpu_dispatch Function?");
2988   llvm::Type *DeclTy = getTypes().ConvertType(FD->getType());
2989 
2990   if (const auto *CXXFD = dyn_cast<CXXMethodDecl>(FD)) {
2991     const CGFunctionInfo &FInfo = getTypes().arrangeCXXMethodDeclaration(CXXFD);
2992     DeclTy = getTypes().GetFunctionType(FInfo);
2993   }
2994 
2995   StringRef ResolverName = getMangledName(GD);
2996 
2997   llvm::Type *ResolverType;
2998   GlobalDecl ResolverGD;
2999   if (getTarget().supportsIFunc())
3000     ResolverType = llvm::FunctionType::get(
3001         llvm::PointerType::get(DeclTy,
3002                                Context.getTargetAddressSpace(FD->getType())),
3003         false);
3004   else {
3005     ResolverType = DeclTy;
3006     ResolverGD = GD;
3007   }
3008 
3009   auto *ResolverFunc = cast<llvm::Function>(GetOrCreateLLVMFunction(
3010       ResolverName, ResolverType, ResolverGD, /*ForVTable=*/false));
3011   ResolverFunc->setLinkage(llvm::Function::WeakODRLinkage);
3012   if (supportsCOMDAT())
3013     ResolverFunc->setComdat(
3014         getModule().getOrInsertComdat(ResolverFunc->getName()));
3015 
3016   SmallVector<CodeGenFunction::MultiVersionResolverOption, 10> Options;
3017   const TargetInfo &Target = getTarget();
3018   unsigned Index = 0;
3019   for (const IdentifierInfo *II : DD->cpus()) {
3020     // Get the name of the target function so we can look it up/create it.
3021     std::string MangledName = getMangledNameImpl(*this, GD, FD, true) +
3022                               getCPUSpecificMangling(*this, II->getName());
3023 
3024     llvm::Constant *Func = GetGlobalValue(MangledName);
3025 
3026     if (!Func) {
3027       GlobalDecl ExistingDecl = Manglings.lookup(MangledName);
3028       if (ExistingDecl.getDecl() &&
3029           ExistingDecl.getDecl()->getAsFunction()->isDefined()) {
3030         EmitGlobalFunctionDefinition(ExistingDecl, nullptr);
3031         Func = GetGlobalValue(MangledName);
3032       } else {
3033         if (!ExistingDecl.getDecl())
3034           ExistingDecl = GD.getWithMultiVersionIndex(Index);
3035 
3036       Func = GetOrCreateLLVMFunction(
3037           MangledName, DeclTy, ExistingDecl,
3038           /*ForVTable=*/false, /*DontDefer=*/true,
3039           /*IsThunk=*/false, llvm::AttributeList(), ForDefinition);
3040       }
3041     }
3042 
3043     llvm::SmallVector<StringRef, 32> Features;
3044     Target.getCPUSpecificCPUDispatchFeatures(II->getName(), Features);
3045     llvm::transform(Features, Features.begin(),
3046                     [](StringRef Str) { return Str.substr(1); });
3047     Features.erase(std::remove_if(
3048         Features.begin(), Features.end(), [&Target](StringRef Feat) {
3049           return !Target.validateCpuSupports(Feat);
3050         }), Features.end());
3051     Options.emplace_back(cast<llvm::Function>(Func), StringRef{}, Features);
3052     ++Index;
3053   }
3054 
3055   llvm::sort(
3056       Options, [](const CodeGenFunction::MultiVersionResolverOption &LHS,
3057                   const CodeGenFunction::MultiVersionResolverOption &RHS) {
3058         return CodeGenFunction::GetX86CpuSupportsMask(LHS.Conditions.Features) >
3059                CodeGenFunction::GetX86CpuSupportsMask(RHS.Conditions.Features);
3060       });
3061 
3062   // If the list contains multiple 'default' versions, such as when it contains
3063   // 'pentium' and 'generic', don't emit the call to the generic one (since we
3064   // always run on at least a 'pentium'). We do this by deleting the 'least
3065   // advanced' (read, lowest mangling letter).
3066   while (Options.size() > 1 &&
3067          CodeGenFunction::GetX86CpuSupportsMask(
3068              (Options.end() - 2)->Conditions.Features) == 0) {
3069     StringRef LHSName = (Options.end() - 2)->Function->getName();
3070     StringRef RHSName = (Options.end() - 1)->Function->getName();
3071     if (LHSName.compare(RHSName) < 0)
3072       Options.erase(Options.end() - 2);
3073     else
3074       Options.erase(Options.end() - 1);
3075   }
3076 
3077   CodeGenFunction CGF(*this);
3078   CGF.EmitMultiVersionResolver(ResolverFunc, Options);
3079 
3080   if (getTarget().supportsIFunc()) {
3081     std::string AliasName = getMangledNameImpl(
3082         *this, GD, FD, /*OmitMultiVersionMangling=*/true);
3083     llvm::Constant *AliasFunc = GetGlobalValue(AliasName);
3084     if (!AliasFunc) {
3085       auto *IFunc = cast<llvm::GlobalIFunc>(GetOrCreateLLVMFunction(
3086           AliasName, DeclTy, GD, /*ForVTable=*/false, /*DontDefer=*/true,
3087           /*IsThunk=*/false, llvm::AttributeList(), NotForDefinition));
3088       auto *GA = llvm::GlobalAlias::create(
3089          DeclTy, 0, getFunctionLinkage(GD), AliasName, IFunc, &getModule());
3090       GA->setLinkage(llvm::Function::WeakODRLinkage);
3091       SetCommonAttributes(GD, GA);
3092     }
3093   }
3094 }
3095 
3096 /// If a dispatcher for the specified mangled name is not in the module, create
3097 /// and return an llvm Function with the specified type.
3098 llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(
3099     GlobalDecl GD, llvm::Type *DeclTy, const FunctionDecl *FD) {
3100   std::string MangledName =
3101       getMangledNameImpl(*this, GD, FD, /*OmitMultiVersionMangling=*/true);
3102 
3103   // Holds the name of the resolver, in ifunc mode this is the ifunc (which has
3104   // a separate resolver).
3105   std::string ResolverName = MangledName;
3106   if (getTarget().supportsIFunc())
3107     ResolverName += ".ifunc";
3108   else if (FD->isTargetMultiVersion())
3109     ResolverName += ".resolver";
3110 
3111   // If this already exists, just return that one.
3112   if (llvm::GlobalValue *ResolverGV = GetGlobalValue(ResolverName))
3113     return ResolverGV;
3114 
3115   // Since this is the first time we've created this IFunc, make sure
3116   // that we put this multiversioned function into the list to be
3117   // replaced later if necessary (target multiversioning only).
3118   if (!FD->isCPUDispatchMultiVersion() && !FD->isCPUSpecificMultiVersion())
3119     MultiVersionFuncs.push_back(GD);
3120 
3121   if (getTarget().supportsIFunc()) {
3122     llvm::Type *ResolverType = llvm::FunctionType::get(
3123         llvm::PointerType::get(
3124             DeclTy, getContext().getTargetAddressSpace(FD->getType())),
3125         false);
3126     llvm::Constant *Resolver = GetOrCreateLLVMFunction(
3127         MangledName + ".resolver", ResolverType, GlobalDecl{},
3128         /*ForVTable=*/false);
3129     llvm::GlobalIFunc *GIF = llvm::GlobalIFunc::create(
3130         DeclTy, 0, llvm::Function::WeakODRLinkage, "", Resolver, &getModule());
3131     GIF->setName(ResolverName);
3132     SetCommonAttributes(FD, GIF);
3133 
3134     return GIF;
3135   }
3136 
3137   llvm::Constant *Resolver = GetOrCreateLLVMFunction(
3138       ResolverName, DeclTy, GlobalDecl{}, /*ForVTable=*/false);
3139   assert(isa<llvm::GlobalValue>(Resolver) &&
3140          "Resolver should be created for the first time");
3141   SetCommonAttributes(FD, cast<llvm::GlobalValue>(Resolver));
3142   return Resolver;
3143 }
3144 
3145 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the
3146 /// module, create and return an llvm Function with the specified type. If there
3147 /// is something in the module with the specified name, return it potentially
3148 /// bitcasted to the right type.
3149 ///
3150 /// If D is non-null, it specifies a decl that correspond to this.  This is used
3151 /// to set the attributes on the function when it is first created.
3152 llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
3153     StringRef MangledName, llvm::Type *Ty, GlobalDecl GD, bool ForVTable,
3154     bool DontDefer, bool IsThunk, llvm::AttributeList ExtraAttrs,
3155     ForDefinition_t IsForDefinition) {
3156   const Decl *D = GD.getDecl();
3157 
3158   // Any attempts to use a MultiVersion function should result in retrieving
3159   // the iFunc instead. Name Mangling will handle the rest of the changes.
3160   if (const FunctionDecl *FD = cast_or_null<FunctionDecl>(D)) {
3161     // For the device mark the function as one that should be emitted.
3162     if (getLangOpts().OpenMPIsDevice && OpenMPRuntime &&
3163         !OpenMPRuntime->markAsGlobalTarget(GD) && FD->isDefined() &&
3164         !DontDefer && !IsForDefinition) {
3165       if (const FunctionDecl *FDDef = FD->getDefinition()) {
3166         GlobalDecl GDDef;
3167         if (const auto *CD = dyn_cast<CXXConstructorDecl>(FDDef))
3168           GDDef = GlobalDecl(CD, GD.getCtorType());
3169         else if (const auto *DD = dyn_cast<CXXDestructorDecl>(FDDef))
3170           GDDef = GlobalDecl(DD, GD.getDtorType());
3171         else
3172           GDDef = GlobalDecl(FDDef);
3173         EmitGlobal(GDDef);
3174       }
3175     }
3176 
3177     if (FD->isMultiVersion()) {
3178       if (FD->hasAttr<TargetAttr>())
3179         UpdateMultiVersionNames(GD, FD);
3180       if (!IsForDefinition)
3181         return GetOrCreateMultiVersionResolver(GD, Ty, FD);
3182     }
3183   }
3184 
3185   // Lookup the entry, lazily creating it if necessary.
3186   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
3187   if (Entry) {
3188     if (WeakRefReferences.erase(Entry)) {
3189       const FunctionDecl *FD = cast_or_null<FunctionDecl>(D);
3190       if (FD && !FD->hasAttr<WeakAttr>())
3191         Entry->setLinkage(llvm::Function::ExternalLinkage);
3192     }
3193 
3194     // Handle dropped DLL attributes.
3195     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>()) {
3196       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
3197       setDSOLocal(Entry);
3198     }
3199 
3200     // If there are two attempts to define the same mangled name, issue an
3201     // error.
3202     if (IsForDefinition && !Entry->isDeclaration()) {
3203       GlobalDecl OtherGD;
3204       // Check that GD is not yet in DiagnosedConflictingDefinitions is required
3205       // to make sure that we issue an error only once.
3206       if (lookupRepresentativeDecl(MangledName, OtherGD) &&
3207           (GD.getCanonicalDecl().getDecl() !=
3208            OtherGD.getCanonicalDecl().getDecl()) &&
3209           DiagnosedConflictingDefinitions.insert(GD).second) {
3210         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
3211             << MangledName;
3212         getDiags().Report(OtherGD.getDecl()->getLocation(),
3213                           diag::note_previous_definition);
3214       }
3215     }
3216 
3217     if ((isa<llvm::Function>(Entry) || isa<llvm::GlobalAlias>(Entry)) &&
3218         (Entry->getValueType() == Ty)) {
3219       return Entry;
3220     }
3221 
3222     // Make sure the result is of the correct type.
3223     // (If function is requested for a definition, we always need to create a new
3224     // function, not just return a bitcast.)
3225     if (!IsForDefinition)
3226       return llvm::ConstantExpr::getBitCast(Entry, Ty->getPointerTo());
3227   }
3228 
3229   // This function doesn't have a complete type (for example, the return
3230   // type is an incomplete struct). Use a fake type instead, and make
3231   // sure not to try to set attributes.
3232   bool IsIncompleteFunction = false;
3233 
3234   llvm::FunctionType *FTy;
3235   if (isa<llvm::FunctionType>(Ty)) {
3236     FTy = cast<llvm::FunctionType>(Ty);
3237   } else {
3238     FTy = llvm::FunctionType::get(VoidTy, false);
3239     IsIncompleteFunction = true;
3240   }
3241 
3242   llvm::Function *F =
3243       llvm::Function::Create(FTy, llvm::Function::ExternalLinkage,
3244                              Entry ? StringRef() : MangledName, &getModule());
3245 
3246   // If we already created a function with the same mangled name (but different
3247   // type) before, take its name and add it to the list of functions to be
3248   // replaced with F at the end of CodeGen.
3249   //
3250   // This happens if there is a prototype for a function (e.g. "int f()") and
3251   // then a definition of a different type (e.g. "int f(int x)").
3252   if (Entry) {
3253     F->takeName(Entry);
3254 
3255     // This might be an implementation of a function without a prototype, in
3256     // which case, try to do special replacement of calls which match the new
3257     // prototype.  The really key thing here is that we also potentially drop
3258     // arguments from the call site so as to make a direct call, which makes the
3259     // inliner happier and suppresses a number of optimizer warnings (!) about
3260     // dropping arguments.
3261     if (!Entry->use_empty()) {
3262       ReplaceUsesOfNonProtoTypeWithRealFunction(Entry, F);
3263       Entry->removeDeadConstantUsers();
3264     }
3265 
3266     llvm::Constant *BC = llvm::ConstantExpr::getBitCast(
3267         F, Entry->getValueType()->getPointerTo());
3268     addGlobalValReplacement(Entry, BC);
3269   }
3270 
3271   assert(F->getName() == MangledName && "name was uniqued!");
3272   if (D)
3273     SetFunctionAttributes(GD, F, IsIncompleteFunction, IsThunk);
3274   if (ExtraAttrs.hasAttributes(llvm::AttributeList::FunctionIndex)) {
3275     llvm::AttrBuilder B(ExtraAttrs, llvm::AttributeList::FunctionIndex);
3276     F->addAttributes(llvm::AttributeList::FunctionIndex, B);
3277   }
3278 
3279   if (!DontDefer) {
3280     // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
3281     // each other bottoming out with the base dtor.  Therefore we emit non-base
3282     // dtors on usage, even if there is no dtor definition in the TU.
3283     if (D && isa<CXXDestructorDecl>(D) &&
3284         getCXXABI().useThunkForDtorVariant(cast<CXXDestructorDecl>(D),
3285                                            GD.getDtorType()))
3286       addDeferredDeclToEmit(GD);
3287 
3288     // This is the first use or definition of a mangled name.  If there is a
3289     // deferred decl with this name, remember that we need to emit it at the end
3290     // of the file.
3291     auto DDI = DeferredDecls.find(MangledName);
3292     if (DDI != DeferredDecls.end()) {
3293       // Move the potentially referenced deferred decl to the
3294       // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
3295       // don't need it anymore).
3296       addDeferredDeclToEmit(DDI->second);
3297       DeferredDecls.erase(DDI);
3298 
3299       // Otherwise, there are cases we have to worry about where we're
3300       // using a declaration for which we must emit a definition but where
3301       // we might not find a top-level definition:
3302       //   - member functions defined inline in their classes
3303       //   - friend functions defined inline in some class
3304       //   - special member functions with implicit definitions
3305       // If we ever change our AST traversal to walk into class methods,
3306       // this will be unnecessary.
3307       //
3308       // We also don't emit a definition for a function if it's going to be an
3309       // entry in a vtable, unless it's already marked as used.
3310     } else if (getLangOpts().CPlusPlus && D) {
3311       // Look for a declaration that's lexically in a record.
3312       for (const auto *FD = cast<FunctionDecl>(D)->getMostRecentDecl(); FD;
3313            FD = FD->getPreviousDecl()) {
3314         if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
3315           if (FD->doesThisDeclarationHaveABody()) {
3316             addDeferredDeclToEmit(GD.getWithDecl(FD));
3317             break;
3318           }
3319         }
3320       }
3321     }
3322   }
3323 
3324   // Make sure the result is of the requested type.
3325   if (!IsIncompleteFunction) {
3326     assert(F->getFunctionType() == Ty);
3327     return F;
3328   }
3329 
3330   llvm::Type *PTy = llvm::PointerType::getUnqual(Ty);
3331   return llvm::ConstantExpr::getBitCast(F, PTy);
3332 }
3333 
3334 /// GetAddrOfFunction - Return the address of the given function.  If Ty is
3335 /// non-null, then this function will use the specified type if it has to
3336 /// create it (this occurs when we see a definition of the function).
3337 llvm::Constant *CodeGenModule::GetAddrOfFunction(GlobalDecl GD,
3338                                                  llvm::Type *Ty,
3339                                                  bool ForVTable,
3340                                                  bool DontDefer,
3341                                               ForDefinition_t IsForDefinition) {
3342   assert(!cast<FunctionDecl>(GD.getDecl())->isConsteval() &&
3343          "consteval function should never be emitted");
3344   // If there was no specific requested type, just convert it now.
3345   if (!Ty) {
3346     const auto *FD = cast<FunctionDecl>(GD.getDecl());
3347     Ty = getTypes().ConvertType(FD->getType());
3348   }
3349 
3350   // Devirtualized destructor calls may come through here instead of via
3351   // getAddrOfCXXStructor. Make sure we use the MS ABI base destructor instead
3352   // of the complete destructor when necessary.
3353   if (const auto *DD = dyn_cast<CXXDestructorDecl>(GD.getDecl())) {
3354     if (getTarget().getCXXABI().isMicrosoft() &&
3355         GD.getDtorType() == Dtor_Complete &&
3356         DD->getParent()->getNumVBases() == 0)
3357       GD = GlobalDecl(DD, Dtor_Base);
3358   }
3359 
3360   StringRef MangledName = getMangledName(GD);
3361   return GetOrCreateLLVMFunction(MangledName, Ty, GD, ForVTable, DontDefer,
3362                                  /*IsThunk=*/false, llvm::AttributeList(),
3363                                  IsForDefinition);
3364 }
3365 
3366 static const FunctionDecl *
3367 GetRuntimeFunctionDecl(ASTContext &C, StringRef Name) {
3368   TranslationUnitDecl *TUDecl = C.getTranslationUnitDecl();
3369   DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
3370 
3371   IdentifierInfo &CII = C.Idents.get(Name);
3372   for (const auto &Result : DC->lookup(&CII))
3373     if (const auto FD = dyn_cast<FunctionDecl>(Result))
3374       return FD;
3375 
3376   if (!C.getLangOpts().CPlusPlus)
3377     return nullptr;
3378 
3379   // Demangle the premangled name from getTerminateFn()
3380   IdentifierInfo &CXXII =
3381       (Name == "_ZSt9terminatev" || Name == "?terminate@@YAXXZ")
3382           ? C.Idents.get("terminate")
3383           : C.Idents.get(Name);
3384 
3385   for (const auto &N : {"__cxxabiv1", "std"}) {
3386     IdentifierInfo &NS = C.Idents.get(N);
3387     for (const auto &Result : DC->lookup(&NS)) {
3388       NamespaceDecl *ND = dyn_cast<NamespaceDecl>(Result);
3389       if (auto LSD = dyn_cast<LinkageSpecDecl>(Result))
3390         for (const auto &Result : LSD->lookup(&NS))
3391           if ((ND = dyn_cast<NamespaceDecl>(Result)))
3392             break;
3393 
3394       if (ND)
3395         for (const auto &Result : ND->lookup(&CXXII))
3396           if (const auto *FD = dyn_cast<FunctionDecl>(Result))
3397             return FD;
3398     }
3399   }
3400 
3401   return nullptr;
3402 }
3403 
3404 /// CreateRuntimeFunction - Create a new runtime function with the specified
3405 /// type and name.
3406 llvm::FunctionCallee
3407 CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
3408                                      llvm::AttributeList ExtraAttrs, bool Local,
3409                                      bool AssumeConvergent) {
3410   if (AssumeConvergent) {
3411     ExtraAttrs =
3412         ExtraAttrs.addAttribute(VMContext, llvm::AttributeList::FunctionIndex,
3413                                 llvm::Attribute::Convergent);
3414   }
3415 
3416   llvm::Constant *C =
3417       GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(), /*ForVTable=*/false,
3418                               /*DontDefer=*/false, /*IsThunk=*/false,
3419                               ExtraAttrs);
3420 
3421   if (auto *F = dyn_cast<llvm::Function>(C)) {
3422     if (F->empty()) {
3423       F->setCallingConv(getRuntimeCC());
3424 
3425       // In Windows Itanium environments, try to mark runtime functions
3426       // dllimport. For Mingw and MSVC, don't. We don't really know if the user
3427       // will link their standard library statically or dynamically. Marking
3428       // functions imported when they are not imported can cause linker errors
3429       // and warnings.
3430       if (!Local && getTriple().isWindowsItaniumEnvironment() &&
3431           !getCodeGenOpts().LTOVisibilityPublicStd) {
3432         const FunctionDecl *FD = GetRuntimeFunctionDecl(Context, Name);
3433         if (!FD || FD->hasAttr<DLLImportAttr>()) {
3434           F->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
3435           F->setLinkage(llvm::GlobalValue::ExternalLinkage);
3436         }
3437       }
3438       setDSOLocal(F);
3439     }
3440   }
3441 
3442   return {FTy, C};
3443 }
3444 
3445 /// isTypeConstant - Determine whether an object of this type can be emitted
3446 /// as a constant.
3447 ///
3448 /// If ExcludeCtor is true, the duration when the object's constructor runs
3449 /// will not be considered. The caller will need to verify that the object is
3450 /// not written to during its construction.
3451 bool CodeGenModule::isTypeConstant(QualType Ty, bool ExcludeCtor) {
3452   if (!Ty.isConstant(Context) && !Ty->isReferenceType())
3453     return false;
3454 
3455   if (Context.getLangOpts().CPlusPlus) {
3456     if (const CXXRecordDecl *Record
3457           = Context.getBaseElementType(Ty)->getAsCXXRecordDecl())
3458       return ExcludeCtor && !Record->hasMutableFields() &&
3459              Record->hasTrivialDestructor();
3460   }
3461 
3462   return true;
3463 }
3464 
3465 /// GetOrCreateLLVMGlobal - If the specified mangled name is not in the module,
3466 /// create and return an llvm GlobalVariable with the specified type.  If there
3467 /// is something in the module with the specified name, return it potentially
3468 /// bitcasted to the right type.
3469 ///
3470 /// If D is non-null, it specifies a decl that correspond to this.  This is used
3471 /// to set the attributes on the global when it is first created.
3472 ///
3473 /// If IsForDefinition is true, it is guaranteed that an actual global with
3474 /// type Ty will be returned, not conversion of a variable with the same
3475 /// mangled name but some other type.
3476 llvm::Constant *
3477 CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
3478                                      llvm::PointerType *Ty,
3479                                      const VarDecl *D,
3480                                      ForDefinition_t IsForDefinition) {
3481   // Lookup the entry, lazily creating it if necessary.
3482   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
3483   if (Entry) {
3484     if (WeakRefReferences.erase(Entry)) {
3485       if (D && !D->hasAttr<WeakAttr>())
3486         Entry->setLinkage(llvm::Function::ExternalLinkage);
3487     }
3488 
3489     // Handle dropped DLL attributes.
3490     if (D && !D->hasAttr<DLLImportAttr>() && !D->hasAttr<DLLExportAttr>())
3491       Entry->setDLLStorageClass(llvm::GlobalValue::DefaultStorageClass);
3492 
3493     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd && D)
3494       getOpenMPRuntime().registerTargetGlobalVariable(D, Entry);
3495 
3496     if (Entry->getType() == Ty)
3497       return Entry;
3498 
3499     // If there are two attempts to define the same mangled name, issue an
3500     // error.
3501     if (IsForDefinition && !Entry->isDeclaration()) {
3502       GlobalDecl OtherGD;
3503       const VarDecl *OtherD;
3504 
3505       // Check that D is not yet in DiagnosedConflictingDefinitions is required
3506       // to make sure that we issue an error only once.
3507       if (D && lookupRepresentativeDecl(MangledName, OtherGD) &&
3508           (D->getCanonicalDecl() != OtherGD.getCanonicalDecl().getDecl()) &&
3509           (OtherD = dyn_cast<VarDecl>(OtherGD.getDecl())) &&
3510           OtherD->hasInit() &&
3511           DiagnosedConflictingDefinitions.insert(D).second) {
3512         getDiags().Report(D->getLocation(), diag::err_duplicate_mangled_name)
3513             << MangledName;
3514         getDiags().Report(OtherGD.getDecl()->getLocation(),
3515                           diag::note_previous_definition);
3516       }
3517     }
3518 
3519     // Make sure the result is of the correct type.
3520     if (Entry->getType()->getAddressSpace() != Ty->getAddressSpace())
3521       return llvm::ConstantExpr::getAddrSpaceCast(Entry, Ty);
3522 
3523     // (If global is requested for a definition, we always need to create a new
3524     // global, not just return a bitcast.)
3525     if (!IsForDefinition)
3526       return llvm::ConstantExpr::getBitCast(Entry, Ty);
3527   }
3528 
3529   auto AddrSpace = GetGlobalVarAddressSpace(D);
3530   auto TargetAddrSpace = getContext().getTargetAddressSpace(AddrSpace);
3531 
3532   auto *GV = new llvm::GlobalVariable(
3533       getModule(), Ty->getElementType(), false,
3534       llvm::GlobalValue::ExternalLinkage, nullptr, MangledName, nullptr,
3535       llvm::GlobalVariable::NotThreadLocal, TargetAddrSpace);
3536 
3537   // If we already created a global with the same mangled name (but different
3538   // type) before, take its name and remove it from its parent.
3539   if (Entry) {
3540     GV->takeName(Entry);
3541 
3542     if (!Entry->use_empty()) {
3543       llvm::Constant *NewPtrForOldDecl =
3544           llvm::ConstantExpr::getBitCast(GV, Entry->getType());
3545       Entry->replaceAllUsesWith(NewPtrForOldDecl);
3546     }
3547 
3548     Entry->eraseFromParent();
3549   }
3550 
3551   // This is the first use or definition of a mangled name.  If there is a
3552   // deferred decl with this name, remember that we need to emit it at the end
3553   // of the file.
3554   auto DDI = DeferredDecls.find(MangledName);
3555   if (DDI != DeferredDecls.end()) {
3556     // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
3557     // list, and remove it from DeferredDecls (since we don't need it anymore).
3558     addDeferredDeclToEmit(DDI->second);
3559     DeferredDecls.erase(DDI);
3560   }
3561 
3562   // Handle things which are present even on external declarations.
3563   if (D) {
3564     if (LangOpts.OpenMP && !LangOpts.OpenMPSimd)
3565       getOpenMPRuntime().registerTargetGlobalVariable(D, GV);
3566 
3567     // FIXME: This code is overly simple and should be merged with other global
3568     // handling.
3569     GV->setConstant(isTypeConstant(D->getType(), false));
3570 
3571     GV->setAlignment(getContext().getDeclAlign(D).getAsAlign());
3572 
3573     setLinkageForGV(GV, D);
3574 
3575     if (D->getTLSKind()) {
3576       if (D->getTLSKind() == VarDecl::TLS_Dynamic)
3577         CXXThreadLocals.push_back(D);
3578       setTLSMode(GV, *D);
3579     }
3580 
3581     setGVProperties(GV, D);
3582 
3583     // If required by the ABI, treat declarations of static data members with
3584     // inline initializers as definitions.
3585     if (getContext().isMSStaticDataMemberInlineDefinition(D)) {
3586       EmitGlobalVarDefinition(D);
3587     }
3588 
3589     // Emit section information for extern variables.
3590     if (D->hasExternalStorage()) {
3591       if (const SectionAttr *SA = D->getAttr<SectionAttr>())
3592         GV->setSection(SA->getName());
3593     }
3594 
3595     // Handle XCore specific ABI requirements.
3596     if (getTriple().getArch() == llvm::Triple::xcore &&
3597         D->getLanguageLinkage() == CLanguageLinkage &&
3598         D->getType().isConstant(Context) &&
3599         isExternallyVisible(D->getLinkageAndVisibility().getLinkage()))
3600       GV->setSection(".cp.rodata");
3601 
3602     // Check if we a have a const declaration with an initializer, we may be
3603     // able to emit it as available_externally to expose it's value to the
3604     // optimizer.
3605     if (Context.getLangOpts().CPlusPlus && GV->hasExternalLinkage() &&
3606         D->getType().isConstQualified() && !GV->hasInitializer() &&
3607         !D->hasDefinition() && D->hasInit() && !D->hasAttr<DLLImportAttr>()) {
3608       const auto *Record =
3609           Context.getBaseElementType(D->getType())->getAsCXXRecordDecl();
3610       bool HasMutableFields = Record && Record->hasMutableFields();
3611       if (!HasMutableFields) {
3612         const VarDecl *InitDecl;
3613         const Expr *InitExpr = D->getAnyInitializer(InitDecl);
3614         if (InitExpr) {
3615           ConstantEmitter emitter(*this);
3616           llvm::Constant *Init = emitter.tryEmitForInitializer(*InitDecl);
3617           if (Init) {
3618             auto *InitType = Init->getType();
3619             if (GV->getValueType() != InitType) {
3620               // The type of the initializer does not match the definition.
3621               // This happens when an initializer has a different type from
3622               // the type of the global (because of padding at the end of a
3623               // structure for instance).
3624               GV->setName(StringRef());
3625               // Make a new global with the correct type, this is now guaranteed
3626               // to work.
3627               auto *NewGV = cast<llvm::GlobalVariable>(
3628                   GetAddrOfGlobalVar(D, InitType, IsForDefinition)
3629                       ->stripPointerCasts());
3630 
3631               // Erase the old global, since it is no longer used.
3632               GV->eraseFromParent();
3633               GV = NewGV;
3634             } else {
3635               GV->setInitializer(Init);
3636               GV->setConstant(true);
3637               GV->setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
3638             }
3639             emitter.finalize(GV);
3640           }
3641         }
3642       }
3643     }
3644   }
3645 
3646   if (GV->isDeclaration())
3647     getTargetCodeGenInfo().setTargetAttributes(D, GV, *this);
3648 
3649   LangAS ExpectedAS =
3650       D ? D->getType().getAddressSpace()
3651         : (LangOpts.OpenCL ? LangAS::opencl_global : LangAS::Default);
3652   assert(getContext().getTargetAddressSpace(ExpectedAS) ==
3653          Ty->getPointerAddressSpace());
3654   if (AddrSpace != ExpectedAS)
3655     return getTargetCodeGenInfo().performAddrSpaceCast(*this, GV, AddrSpace,
3656                                                        ExpectedAS, Ty);
3657 
3658   return GV;
3659 }
3660 
3661 llvm::Constant *
3662 CodeGenModule::GetAddrOfGlobal(GlobalDecl GD, ForDefinition_t IsForDefinition) {
3663   const Decl *D = GD.getDecl();
3664 
3665   if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D))
3666     return getAddrOfCXXStructor(GD, /*FnInfo=*/nullptr, /*FnType=*/nullptr,
3667                                 /*DontDefer=*/false, IsForDefinition);
3668 
3669   if (isa<CXXMethodDecl>(D)) {
3670     auto FInfo =
3671         &getTypes().arrangeCXXMethodDeclaration(cast<CXXMethodDecl>(D));
3672     auto Ty = getTypes().GetFunctionType(*FInfo);
3673     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
3674                              IsForDefinition);
3675   }
3676 
3677   if (isa<FunctionDecl>(D)) {
3678     const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
3679     llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
3680     return GetAddrOfFunction(GD, Ty, /*ForVTable=*/false, /*DontDefer=*/false,
3681                              IsForDefinition);
3682   }
3683 
3684   return GetAddrOfGlobalVar(cast<VarDecl>(D), /*Ty=*/nullptr, IsForDefinition);
3685 }
3686 
3687 llvm::GlobalVariable *CodeGenModule::CreateOrReplaceCXXRuntimeVariable(
3688     StringRef Name, llvm::Type *Ty, llvm::GlobalValue::LinkageTypes Linkage,
3689     unsigned Alignment) {
3690   llvm::GlobalVariable *GV = getModule().getNamedGlobal(Name);
3691   llvm::GlobalVariable *OldGV = nullptr;
3692 
3693   if (GV) {
3694     // Check if the variable has the right type.
3695     if (GV->getValueType() == Ty)
3696       return GV;
3697 
3698     // Because C++ name mangling, the only way we can end up with an already
3699     // existing global with the same name is if it has been declared extern "C".
3700     assert(GV->isDeclaration() && "Declaration has wrong type!");
3701     OldGV = GV;
3702   }
3703 
3704   // Create a new variable.
3705   GV = new llvm::GlobalVariable(getModule(), Ty, /*isConstant=*/true,
3706                                 Linkage, nullptr, Name);
3707 
3708   if (OldGV) {
3709     // Replace occurrences of the old variable if needed.
3710     GV->takeName(OldGV);
3711 
3712     if (!OldGV->use_empty()) {
3713       llvm::Constant *NewPtrForOldDecl =
3714       llvm::ConstantExpr::getBitCast(GV, OldGV->getType());
3715       OldGV->replaceAllUsesWith(NewPtrForOldDecl);
3716     }
3717 
3718     OldGV->eraseFromParent();
3719   }
3720 
3721   if (supportsCOMDAT() && GV->isWeakForLinker() &&
3722       !GV->hasAvailableExternallyLinkage())
3723     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
3724 
3725   GV->setAlignment(llvm::MaybeAlign(Alignment));
3726 
3727   return GV;
3728 }
3729 
3730 /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
3731 /// given global variable.  If Ty is non-null and if the global doesn't exist,
3732 /// then it will be created with the specified type instead of whatever the
3733 /// normal requested type would be. If IsForDefinition is true, it is guaranteed
3734 /// that an actual global with type Ty will be returned, not conversion of a
3735 /// variable with the same mangled name but some other type.
3736 llvm::Constant *CodeGenModule::GetAddrOfGlobalVar(const VarDecl *D,
3737                                                   llvm::Type *Ty,
3738                                            ForDefinition_t IsForDefinition) {
3739   assert(D->hasGlobalStorage() && "Not a global variable");
3740   QualType ASTTy = D->getType();
3741   if (!Ty)
3742     Ty = getTypes().ConvertTypeForMem(ASTTy);
3743 
3744   llvm::PointerType *PTy =
3745     llvm::PointerType::get(Ty, getContext().getTargetAddressSpace(ASTTy));
3746 
3747   StringRef MangledName = getMangledName(D);
3748   return GetOrCreateLLVMGlobal(MangledName, PTy, D, IsForDefinition);
3749 }
3750 
3751 /// CreateRuntimeVariable - Create a new runtime global variable with the
3752 /// specified type and name.
3753 llvm::Constant *
3754 CodeGenModule::CreateRuntimeVariable(llvm::Type *Ty,
3755                                      StringRef Name) {
3756   auto PtrTy =
3757       getContext().getLangOpts().OpenCL
3758           ? llvm::PointerType::get(
3759                 Ty, getContext().getTargetAddressSpace(LangAS::opencl_global))
3760           : llvm::PointerType::getUnqual(Ty);
3761   auto *Ret = GetOrCreateLLVMGlobal(Name, PtrTy, nullptr);
3762   setDSOLocal(cast<llvm::GlobalValue>(Ret->stripPointerCasts()));
3763   return Ret;
3764 }
3765 
3766 void CodeGenModule::EmitTentativeDefinition(const VarDecl *D) {
3767   assert(!D->getInit() && "Cannot emit definite definitions here!");
3768 
3769   StringRef MangledName = getMangledName(D);
3770   llvm::GlobalValue *GV = GetGlobalValue(MangledName);
3771 
3772   // We already have a definition, not declaration, with the same mangled name.
3773   // Emitting of declaration is not required (and actually overwrites emitted
3774   // definition).
3775   if (GV && !GV->isDeclaration())
3776     return;
3777 
3778   // If we have not seen a reference to this variable yet, place it into the
3779   // deferred declarations table to be emitted if needed later.
3780   if (!MustBeEmitted(D) && !GV) {
3781       DeferredDecls[MangledName] = D;
3782       return;
3783   }
3784 
3785   // The tentative definition is the only definition.
3786   EmitGlobalVarDefinition(D);
3787 }
3788 
3789 void CodeGenModule::EmitExternalDeclaration(const VarDecl *D) {
3790   EmitExternalVarDeclaration(D);
3791 }
3792 
3793 CharUnits CodeGenModule::GetTargetTypeStoreSize(llvm::Type *Ty) const {
3794   return Context.toCharUnitsFromBits(
3795       getDataLayout().getTypeStoreSizeInBits(Ty));
3796 }
3797 
3798 LangAS CodeGenModule::GetGlobalVarAddressSpace(const VarDecl *D) {
3799   LangAS AddrSpace = LangAS::Default;
3800   if (LangOpts.OpenCL) {
3801     AddrSpace = D ? D->getType().getAddressSpace() : LangAS::opencl_global;
3802     assert(AddrSpace == LangAS::opencl_global ||
3803            AddrSpace == LangAS::opencl_global_device ||
3804            AddrSpace == LangAS::opencl_global_host ||
3805            AddrSpace == LangAS::opencl_constant ||
3806            AddrSpace == LangAS::opencl_local ||
3807            AddrSpace >= LangAS::FirstTargetAddressSpace);
3808     return AddrSpace;
3809   }
3810 
3811   if (LangOpts.CUDA && LangOpts.CUDAIsDevice) {
3812     if (D && D->hasAttr<CUDAConstantAttr>())
3813       return LangAS::cuda_constant;
3814     else if (D && D->hasAttr<CUDASharedAttr>())
3815       return LangAS::cuda_shared;
3816     else if (D && D->hasAttr<CUDADeviceAttr>())
3817       return LangAS::cuda_device;
3818     else if (D && D->getType().isConstQualified())
3819       return LangAS::cuda_constant;
3820     else
3821       return LangAS::cuda_device;
3822   }
3823 
3824   if (LangOpts.OpenMP) {
3825     LangAS AS;
3826     if (OpenMPRuntime->hasAllocateAttributeForGlobalVar(D, AS))
3827       return AS;
3828   }
3829   return getTargetCodeGenInfo().getGlobalVarAddressSpace(*this, D);
3830 }
3831 
3832 LangAS CodeGenModule::getStringLiteralAddressSpace() const {
3833   // OpenCL v1.2 s6.5.3: a string literal is in the constant address space.
3834   if (LangOpts.OpenCL)
3835     return LangAS::opencl_constant;
3836   if (auto AS = getTarget().getConstantAddressSpace())
3837     return AS.getValue();
3838   return LangAS::Default;
3839 }
3840 
3841 // In address space agnostic languages, string literals are in default address
3842 // space in AST. However, certain targets (e.g. amdgcn) request them to be
3843 // emitted in constant address space in LLVM IR. To be consistent with other
3844 // parts of AST, string literal global variables in constant address space
3845 // need to be casted to default address space before being put into address
3846 // map and referenced by other part of CodeGen.
3847 // In OpenCL, string literals are in constant address space in AST, therefore
3848 // they should not be casted to default address space.
3849 static llvm::Constant *
3850 castStringLiteralToDefaultAddressSpace(CodeGenModule &CGM,
3851                                        llvm::GlobalVariable *GV) {
3852   llvm::Constant *Cast = GV;
3853   if (!CGM.getLangOpts().OpenCL) {
3854     if (auto AS = CGM.getTarget().getConstantAddressSpace()) {
3855       if (AS != LangAS::Default)
3856         Cast = CGM.getTargetCodeGenInfo().performAddrSpaceCast(
3857             CGM, GV, AS.getValue(), LangAS::Default,
3858             GV->getValueType()->getPointerTo(
3859                 CGM.getContext().getTargetAddressSpace(LangAS::Default)));
3860     }
3861   }
3862   return Cast;
3863 }
3864 
3865 template<typename SomeDecl>
3866 void CodeGenModule::MaybeHandleStaticInExternC(const SomeDecl *D,
3867                                                llvm::GlobalValue *GV) {
3868   if (!getLangOpts().CPlusPlus)
3869     return;
3870 
3871   // Must have 'used' attribute, or else inline assembly can't rely on
3872   // the name existing.
3873   if (!D->template hasAttr<UsedAttr>())
3874     return;
3875 
3876   // Must have internal linkage and an ordinary name.
3877   if (!D->getIdentifier() || D->getFormalLinkage() != InternalLinkage)
3878     return;
3879 
3880   // Must be in an extern "C" context. Entities declared directly within
3881   // a record are not extern "C" even if the record is in such a context.
3882   const SomeDecl *First = D->getFirstDecl();
3883   if (First->getDeclContext()->isRecord() || !First->isInExternCContext())
3884     return;
3885 
3886   // OK, this is an internal linkage entity inside an extern "C" linkage
3887   // specification. Make a note of that so we can give it the "expected"
3888   // mangled name if nothing else is using that name.
3889   std::pair<StaticExternCMap::iterator, bool> R =
3890       StaticExternCValues.insert(std::make_pair(D->getIdentifier(), GV));
3891 
3892   // If we have multiple internal linkage entities with the same name
3893   // in extern "C" regions, none of them gets that name.
3894   if (!R.second)
3895     R.first->second = nullptr;
3896 }
3897 
3898 static bool shouldBeInCOMDAT(CodeGenModule &CGM, const Decl &D) {
3899   if (!CGM.supportsCOMDAT())
3900     return false;
3901 
3902   // Do not set COMDAT attribute for CUDA/HIP stub functions to prevent
3903   // them being "merged" by the COMDAT Folding linker optimization.
3904   if (D.hasAttr<CUDAGlobalAttr>())
3905     return false;
3906 
3907   if (D.hasAttr<SelectAnyAttr>())
3908     return true;
3909 
3910   GVALinkage Linkage;
3911   if (auto *VD = dyn_cast<VarDecl>(&D))
3912     Linkage = CGM.getContext().GetGVALinkageForVariable(VD);
3913   else
3914     Linkage = CGM.getContext().GetGVALinkageForFunction(cast<FunctionDecl>(&D));
3915 
3916   switch (Linkage) {
3917   case GVA_Internal:
3918   case GVA_AvailableExternally:
3919   case GVA_StrongExternal:
3920     return false;
3921   case GVA_DiscardableODR:
3922   case GVA_StrongODR:
3923     return true;
3924   }
3925   llvm_unreachable("No such linkage");
3926 }
3927 
3928 void CodeGenModule::maybeSetTrivialComdat(const Decl &D,
3929                                           llvm::GlobalObject &GO) {
3930   if (!shouldBeInCOMDAT(*this, D))
3931     return;
3932   GO.setComdat(TheModule.getOrInsertComdat(GO.getName()));
3933 }
3934 
3935 /// Pass IsTentative as true if you want to create a tentative definition.
3936 void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D,
3937                                             bool IsTentative) {
3938   // OpenCL global variables of sampler type are translated to function calls,
3939   // therefore no need to be translated.
3940   QualType ASTTy = D->getType();
3941   if (getLangOpts().OpenCL && ASTTy->isSamplerT())
3942     return;
3943 
3944   // If this is OpenMP device, check if it is legal to emit this global
3945   // normally.
3946   if (LangOpts.OpenMPIsDevice && OpenMPRuntime &&
3947       OpenMPRuntime->emitTargetGlobalVariable(D))
3948     return;
3949 
3950   llvm::Constant *Init = nullptr;
3951   bool NeedsGlobalCtor = false;
3952   bool NeedsGlobalDtor =
3953       D->needsDestruction(getContext()) == QualType::DK_cxx_destructor;
3954 
3955   const VarDecl *InitDecl;
3956   const Expr *InitExpr = D->getAnyInitializer(InitDecl);
3957 
3958   Optional<ConstantEmitter> emitter;
3959 
3960   // CUDA E.2.4.1 "__shared__ variables cannot have an initialization
3961   // as part of their declaration."  Sema has already checked for
3962   // error cases, so we just need to set Init to UndefValue.
3963   bool IsCUDASharedVar =
3964       getLangOpts().CUDAIsDevice && D->hasAttr<CUDASharedAttr>();
3965   // Shadows of initialized device-side global variables are also left
3966   // undefined.
3967   bool IsCUDAShadowVar =
3968       !getLangOpts().CUDAIsDevice &&
3969       (D->hasAttr<CUDAConstantAttr>() || D->hasAttr<CUDADeviceAttr>() ||
3970        D->hasAttr<CUDASharedAttr>());
3971   bool IsCUDADeviceShadowVar =
3972       getLangOpts().CUDAIsDevice &&
3973       (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
3974        D->getType()->isCUDADeviceBuiltinTextureType());
3975   // HIP pinned shadow of initialized host-side global variables are also
3976   // left undefined.
3977   if (getLangOpts().CUDA &&
3978       (IsCUDASharedVar || IsCUDAShadowVar || IsCUDADeviceShadowVar))
3979     Init = llvm::UndefValue::get(getTypes().ConvertType(ASTTy));
3980   else if (D->hasAttr<LoaderUninitializedAttr>())
3981     Init = llvm::UndefValue::get(getTypes().ConvertType(ASTTy));
3982   else if (!InitExpr) {
3983     // This is a tentative definition; tentative definitions are
3984     // implicitly initialized with { 0 }.
3985     //
3986     // Note that tentative definitions are only emitted at the end of
3987     // a translation unit, so they should never have incomplete
3988     // type. In addition, EmitTentativeDefinition makes sure that we
3989     // never attempt to emit a tentative definition if a real one
3990     // exists. A use may still exists, however, so we still may need
3991     // to do a RAUW.
3992     assert(!ASTTy->isIncompleteType() && "Unexpected incomplete type");
3993     Init = EmitNullConstant(D->getType());
3994   } else {
3995     initializedGlobalDecl = GlobalDecl(D);
3996     emitter.emplace(*this);
3997     Init = emitter->tryEmitForInitializer(*InitDecl);
3998 
3999     if (!Init) {
4000       QualType T = InitExpr->getType();
4001       if (D->getType()->isReferenceType())
4002         T = D->getType();
4003 
4004       if (getLangOpts().CPlusPlus) {
4005         Init = EmitNullConstant(T);
4006         NeedsGlobalCtor = true;
4007       } else {
4008         ErrorUnsupported(D, "static initializer");
4009         Init = llvm::UndefValue::get(getTypes().ConvertType(T));
4010       }
4011     } else {
4012       // We don't need an initializer, so remove the entry for the delayed
4013       // initializer position (just in case this entry was delayed) if we
4014       // also don't need to register a destructor.
4015       if (getLangOpts().CPlusPlus && !NeedsGlobalDtor)
4016         DelayedCXXInitPosition.erase(D);
4017     }
4018   }
4019 
4020   llvm::Type* InitType = Init->getType();
4021   llvm::Constant *Entry =
4022       GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative));
4023 
4024   // Strip off pointer casts if we got them.
4025   Entry = Entry->stripPointerCasts();
4026 
4027   // Entry is now either a Function or GlobalVariable.
4028   auto *GV = dyn_cast<llvm::GlobalVariable>(Entry);
4029 
4030   // We have a definition after a declaration with the wrong type.
4031   // We must make a new GlobalVariable* and update everything that used OldGV
4032   // (a declaration or tentative definition) with the new GlobalVariable*
4033   // (which will be a definition).
4034   //
4035   // This happens if there is a prototype for a global (e.g.
4036   // "extern int x[];") and then a definition of a different type (e.g.
4037   // "int x[10];"). This also happens when an initializer has a different type
4038   // from the type of the global (this happens with unions).
4039   if (!GV || GV->getValueType() != InitType ||
4040       GV->getType()->getAddressSpace() !=
4041           getContext().getTargetAddressSpace(GetGlobalVarAddressSpace(D))) {
4042 
4043     // Move the old entry aside so that we'll create a new one.
4044     Entry->setName(StringRef());
4045 
4046     // Make a new global with the correct type, this is now guaranteed to work.
4047     GV = cast<llvm::GlobalVariable>(
4048         GetAddrOfGlobalVar(D, InitType, ForDefinition_t(!IsTentative))
4049             ->stripPointerCasts());
4050 
4051     // Replace all uses of the old global with the new global
4052     llvm::Constant *NewPtrForOldDecl =
4053         llvm::ConstantExpr::getBitCast(GV, Entry->getType());
4054     Entry->replaceAllUsesWith(NewPtrForOldDecl);
4055 
4056     // Erase the old global, since it is no longer used.
4057     cast<llvm::GlobalValue>(Entry)->eraseFromParent();
4058   }
4059 
4060   MaybeHandleStaticInExternC(D, GV);
4061 
4062   if (D->hasAttr<AnnotateAttr>())
4063     AddGlobalAnnotations(D, GV);
4064 
4065   // Set the llvm linkage type as appropriate.
4066   llvm::GlobalValue::LinkageTypes Linkage =
4067       getLLVMLinkageVarDefinition(D, GV->isConstant());
4068 
4069   // CUDA B.2.1 "The __device__ qualifier declares a variable that resides on
4070   // the device. [...]"
4071   // CUDA B.2.2 "The __constant__ qualifier, optionally used together with
4072   // __device__, declares a variable that: [...]
4073   // Is accessible from all the threads within the grid and from the host
4074   // through the runtime library (cudaGetSymbolAddress() / cudaGetSymbolSize()
4075   // / cudaMemcpyToSymbol() / cudaMemcpyFromSymbol())."
4076   if (GV && LangOpts.CUDA) {
4077     if (LangOpts.CUDAIsDevice) {
4078       if (Linkage != llvm::GlobalValue::InternalLinkage &&
4079           (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>()))
4080         GV->setExternallyInitialized(true);
4081     } else {
4082       // Host-side shadows of external declarations of device-side
4083       // global variables become internal definitions. These have to
4084       // be internal in order to prevent name conflicts with global
4085       // host variables with the same name in a different TUs.
4086       if (D->hasAttr<CUDADeviceAttr>() || D->hasAttr<CUDAConstantAttr>()) {
4087         Linkage = llvm::GlobalValue::InternalLinkage;
4088         // Shadow variables and their properties must be registered with CUDA
4089         // runtime. Skip Extern global variables, which will be registered in
4090         // the TU where they are defined.
4091         if (!D->hasExternalStorage())
4092           getCUDARuntime().registerDeviceVar(D, *GV, !D->hasDefinition(),
4093                                              D->hasAttr<CUDAConstantAttr>());
4094       } else if (D->hasAttr<CUDASharedAttr>()) {
4095         // __shared__ variables are odd. Shadows do get created, but
4096         // they are not registered with the CUDA runtime, so they
4097         // can't really be used to access their device-side
4098         // counterparts. It's not clear yet whether it's nvcc's bug or
4099         // a feature, but we've got to do the same for compatibility.
4100         Linkage = llvm::GlobalValue::InternalLinkage;
4101       } else if (D->getType()->isCUDADeviceBuiltinSurfaceType() ||
4102                  D->getType()->isCUDADeviceBuiltinTextureType()) {
4103         // Builtin surfaces and textures and their template arguments are
4104         // also registered with CUDA runtime.
4105         Linkage = llvm::GlobalValue::InternalLinkage;
4106         const ClassTemplateSpecializationDecl *TD =
4107             cast<ClassTemplateSpecializationDecl>(
4108                 D->getType()->getAs<RecordType>()->getDecl());
4109         const TemplateArgumentList &Args = TD->getTemplateArgs();
4110         if (TD->hasAttr<CUDADeviceBuiltinSurfaceTypeAttr>()) {
4111           assert(Args.size() == 2 &&
4112                  "Unexpected number of template arguments of CUDA device "
4113                  "builtin surface type.");
4114           auto SurfType = Args[1].getAsIntegral();
4115           if (!D->hasExternalStorage())
4116             getCUDARuntime().registerDeviceSurf(D, *GV, !D->hasDefinition(),
4117                                                 SurfType.getSExtValue());
4118         } else {
4119           assert(Args.size() == 3 &&
4120                  "Unexpected number of template arguments of CUDA device "
4121                  "builtin texture type.");
4122           auto TexType = Args[1].getAsIntegral();
4123           auto Normalized = Args[2].getAsIntegral();
4124           if (!D->hasExternalStorage())
4125             getCUDARuntime().registerDeviceTex(D, *GV, !D->hasDefinition(),
4126                                                TexType.getSExtValue(),
4127                                                Normalized.getZExtValue());
4128         }
4129       }
4130     }
4131   }
4132 
4133   GV->setInitializer(Init);
4134   if (emitter)
4135     emitter->finalize(GV);
4136 
4137   // If it is safe to mark the global 'constant', do so now.
4138   GV->setConstant(!NeedsGlobalCtor && !NeedsGlobalDtor &&
4139                   isTypeConstant(D->getType(), true));
4140 
4141   // If it is in a read-only section, mark it 'constant'.
4142   if (const SectionAttr *SA = D->getAttr<SectionAttr>()) {
4143     const ASTContext::SectionInfo &SI = Context.SectionInfos[SA->getName()];
4144     if ((SI.SectionFlags & ASTContext::PSF_Write) == 0)
4145       GV->setConstant(true);
4146   }
4147 
4148   GV->setAlignment(getContext().getDeclAlign(D).getAsAlign());
4149 
4150   // On Darwin, unlike other Itanium C++ ABI platforms, the thread-wrapper
4151   // function is only defined alongside the variable, not also alongside
4152   // callers. Normally, all accesses to a thread_local go through the
4153   // thread-wrapper in order to ensure initialization has occurred, underlying
4154   // variable will never be used other than the thread-wrapper, so it can be
4155   // converted to internal linkage.
4156   //
4157   // However, if the variable has the 'constinit' attribute, it _can_ be
4158   // referenced directly, without calling the thread-wrapper, so the linkage
4159   // must not be changed.
4160   //
4161   // Additionally, if the variable isn't plain external linkage, e.g. if it's
4162   // weak or linkonce, the de-duplication semantics are important to preserve,
4163   // so we don't change the linkage.
4164   if (D->getTLSKind() == VarDecl::TLS_Dynamic &&
4165       Linkage == llvm::GlobalValue::ExternalLinkage &&
4166       Context.getTargetInfo().getTriple().isOSDarwin() &&
4167       !D->hasAttr<ConstInitAttr>())
4168     Linkage = llvm::GlobalValue::InternalLinkage;
4169 
4170   GV->setLinkage(Linkage);
4171   if (D->hasAttr<DLLImportAttr>())
4172     GV->setDLLStorageClass(llvm::GlobalVariable::DLLImportStorageClass);
4173   else if (D->hasAttr<DLLExportAttr>())
4174     GV->setDLLStorageClass(llvm::GlobalVariable::DLLExportStorageClass);
4175   else
4176     GV->setDLLStorageClass(llvm::GlobalVariable::DefaultStorageClass);
4177 
4178   if (Linkage == llvm::GlobalVariable::CommonLinkage) {
4179     // common vars aren't constant even if declared const.
4180     GV->setConstant(false);
4181     // Tentative definition of global variables may be initialized with
4182     // non-zero null pointers. In this case they should have weak linkage
4183     // since common linkage must have zero initializer and must not have
4184     // explicit section therefore cannot have non-zero initial value.
4185     if (!GV->getInitializer()->isNullValue())
4186       GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
4187   }
4188 
4189   setNonAliasAttributes(D, GV);
4190 
4191   if (D->getTLSKind() && !GV->isThreadLocal()) {
4192     if (D->getTLSKind() == VarDecl::TLS_Dynamic)
4193       CXXThreadLocals.push_back(D);
4194     setTLSMode(GV, *D);
4195   }
4196 
4197   maybeSetTrivialComdat(*D, *GV);
4198 
4199   // Emit the initializer function if necessary.
4200   if (NeedsGlobalCtor || NeedsGlobalDtor)
4201     EmitCXXGlobalVarDeclInitFunc(D, GV, NeedsGlobalCtor);
4202 
4203   SanitizerMD->reportGlobalToASan(GV, *D, NeedsGlobalCtor);
4204 
4205   // Emit global variable debug information.
4206   if (CGDebugInfo *DI = getModuleDebugInfo())
4207     if (getCodeGenOpts().hasReducedDebugInfo())
4208       DI->EmitGlobalVariable(GV, D);
4209 }
4210 
4211 void CodeGenModule::EmitExternalVarDeclaration(const VarDecl *D) {
4212   if (CGDebugInfo *DI = getModuleDebugInfo())
4213     if (getCodeGenOpts().hasReducedDebugInfo()) {
4214       QualType ASTTy = D->getType();
4215       llvm::Type *Ty = getTypes().ConvertTypeForMem(D->getType());
4216       llvm::PointerType *PTy =
4217           llvm::PointerType::get(Ty, getContext().getTargetAddressSpace(ASTTy));
4218       llvm::Constant *GV = GetOrCreateLLVMGlobal(D->getName(), PTy, D);
4219       DI->EmitExternalVariable(
4220           cast<llvm::GlobalVariable>(GV->stripPointerCasts()), D);
4221     }
4222 }
4223 
4224 static bool isVarDeclStrongDefinition(const ASTContext &Context,
4225                                       CodeGenModule &CGM, const VarDecl *D,
4226                                       bool NoCommon) {
4227   // Don't give variables common linkage if -fno-common was specified unless it
4228   // was overridden by a NoCommon attribute.
4229   if ((NoCommon || D->hasAttr<NoCommonAttr>()) && !D->hasAttr<CommonAttr>())
4230     return true;
4231 
4232   // C11 6.9.2/2:
4233   //   A declaration of an identifier for an object that has file scope without
4234   //   an initializer, and without a storage-class specifier or with the
4235   //   storage-class specifier static, constitutes a tentative definition.
4236   if (D->getInit() || D->hasExternalStorage())
4237     return true;
4238 
4239   // A variable cannot be both common and exist in a section.
4240   if (D->hasAttr<SectionAttr>())
4241     return true;
4242 
4243   // A variable cannot be both common and exist in a section.
4244   // We don't try to determine which is the right section in the front-end.
4245   // If no specialized section name is applicable, it will resort to default.
4246   if (D->hasAttr<PragmaClangBSSSectionAttr>() ||
4247       D->hasAttr<PragmaClangDataSectionAttr>() ||
4248       D->hasAttr<PragmaClangRelroSectionAttr>() ||
4249       D->hasAttr<PragmaClangRodataSectionAttr>())
4250     return true;
4251 
4252   // Thread local vars aren't considered common linkage.
4253   if (D->getTLSKind())
4254     return true;
4255 
4256   // Tentative definitions marked with WeakImportAttr are true definitions.
4257   if (D->hasAttr<WeakImportAttr>())
4258     return true;
4259 
4260   // A variable cannot be both common and exist in a comdat.
4261   if (shouldBeInCOMDAT(CGM, *D))
4262     return true;
4263 
4264   // Declarations with a required alignment do not have common linkage in MSVC
4265   // mode.
4266   if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
4267     if (D->hasAttr<AlignedAttr>())
4268       return true;
4269     QualType VarType = D->getType();
4270     if (Context.isAlignmentRequired(VarType))
4271       return true;
4272 
4273     if (const auto *RT = VarType->getAs<RecordType>()) {
4274       const RecordDecl *RD = RT->getDecl();
4275       for (const FieldDecl *FD : RD->fields()) {
4276         if (FD->isBitField())
4277           continue;
4278         if (FD->hasAttr<AlignedAttr>())
4279           return true;
4280         if (Context.isAlignmentRequired(FD->getType()))
4281           return true;
4282       }
4283     }
4284   }
4285 
4286   // Microsoft's link.exe doesn't support alignments greater than 32 bytes for
4287   // common symbols, so symbols with greater alignment requirements cannot be
4288   // common.
4289   // Other COFF linkers (ld.bfd and LLD) support arbitrary power-of-two
4290   // alignments for common symbols via the aligncomm directive, so this
4291   // restriction only applies to MSVC environments.
4292   if (Context.getTargetInfo().getTriple().isKnownWindowsMSVCEnvironment() &&
4293       Context.getTypeAlignIfKnown(D->getType()) >
4294           Context.toBits(CharUnits::fromQuantity(32)))
4295     return true;
4296 
4297   return false;
4298 }
4299 
4300 llvm::GlobalValue::LinkageTypes CodeGenModule::getLLVMLinkageForDeclarator(
4301     const DeclaratorDecl *D, GVALinkage Linkage, bool IsConstantVariable) {
4302   if (Linkage == GVA_Internal)
4303     return llvm::Function::InternalLinkage;
4304 
4305   if (D->hasAttr<WeakAttr>()) {
4306     if (IsConstantVariable)
4307       return llvm::GlobalVariable::WeakODRLinkage;
4308     else
4309       return llvm::GlobalVariable::WeakAnyLinkage;
4310   }
4311 
4312   if (const auto *FD = D->getAsFunction())
4313     if (FD->isMultiVersion() && Linkage == GVA_AvailableExternally)
4314       return llvm::GlobalVariable::LinkOnceAnyLinkage;
4315 
4316   // We are guaranteed to have a strong definition somewhere else,
4317   // so we can use available_externally linkage.
4318   if (Linkage == GVA_AvailableExternally)
4319     return llvm::GlobalValue::AvailableExternallyLinkage;
4320 
4321   // Note that Apple's kernel linker doesn't support symbol
4322   // coalescing, so we need to avoid linkonce and weak linkages there.
4323   // Normally, this means we just map to internal, but for explicit
4324   // instantiations we'll map to external.
4325 
4326   // In C++, the compiler has to emit a definition in every translation unit
4327   // that references the function.  We should use linkonce_odr because
4328   // a) if all references in this translation unit are optimized away, we
4329   // don't need to codegen it.  b) if the function persists, it needs to be
4330   // merged with other definitions. c) C++ has the ODR, so we know the
4331   // definition is dependable.
4332   if (Linkage == GVA_DiscardableODR)
4333     return !Context.getLangOpts().AppleKext ? llvm::Function::LinkOnceODRLinkage
4334                                             : llvm::Function::InternalLinkage;
4335 
4336   // An explicit instantiation of a template has weak linkage, since
4337   // explicit instantiations can occur in multiple translation units
4338   // and must all be equivalent. However, we are not allowed to
4339   // throw away these explicit instantiations.
4340   //
4341   // We don't currently support CUDA device code spread out across multiple TUs,
4342   // so say that CUDA templates are either external (for kernels) or internal.
4343   // This lets llvm perform aggressive inter-procedural optimizations.
4344   if (Linkage == GVA_StrongODR) {
4345     if (Context.getLangOpts().AppleKext)
4346       return llvm::Function::ExternalLinkage;
4347     if (Context.getLangOpts().CUDA && Context.getLangOpts().CUDAIsDevice)
4348       return D->hasAttr<CUDAGlobalAttr>() ? llvm::Function::ExternalLinkage
4349                                           : llvm::Function::InternalLinkage;
4350     return llvm::Function::WeakODRLinkage;
4351   }
4352 
4353   // C++ doesn't have tentative definitions and thus cannot have common
4354   // linkage.
4355   if (!getLangOpts().CPlusPlus && isa<VarDecl>(D) &&
4356       !isVarDeclStrongDefinition(Context, *this, cast<VarDecl>(D),
4357                                  CodeGenOpts.NoCommon))
4358     return llvm::GlobalVariable::CommonLinkage;
4359 
4360   // selectany symbols are externally visible, so use weak instead of
4361   // linkonce.  MSVC optimizes away references to const selectany globals, so
4362   // all definitions should be the same and ODR linkage should be used.
4363   // http://msdn.microsoft.com/en-us/library/5tkz6s71.aspx
4364   if (D->hasAttr<SelectAnyAttr>())
4365     return llvm::GlobalVariable::WeakODRLinkage;
4366 
4367   // Otherwise, we have strong external linkage.
4368   assert(Linkage == GVA_StrongExternal);
4369   return llvm::GlobalVariable::ExternalLinkage;
4370 }
4371 
4372 llvm::GlobalValue::LinkageTypes CodeGenModule::getLLVMLinkageVarDefinition(
4373     const VarDecl *VD, bool IsConstant) {
4374   GVALinkage Linkage = getContext().GetGVALinkageForVariable(VD);
4375   return getLLVMLinkageForDeclarator(VD, Linkage, IsConstant);
4376 }
4377 
4378 /// Replace the uses of a function that was declared with a non-proto type.
4379 /// We want to silently drop extra arguments from call sites
4380 static void replaceUsesOfNonProtoConstant(llvm::Constant *old,
4381                                           llvm::Function *newFn) {
4382   // Fast path.
4383   if (old->use_empty()) return;
4384 
4385   llvm::Type *newRetTy = newFn->getReturnType();
4386   SmallVector<llvm::Value*, 4> newArgs;
4387   SmallVector<llvm::OperandBundleDef, 1> newBundles;
4388 
4389   for (llvm::Value::use_iterator ui = old->use_begin(), ue = old->use_end();
4390          ui != ue; ) {
4391     llvm::Value::use_iterator use = ui++; // Increment before the use is erased.
4392     llvm::User *user = use->getUser();
4393 
4394     // Recognize and replace uses of bitcasts.  Most calls to
4395     // unprototyped functions will use bitcasts.
4396     if (auto *bitcast = dyn_cast<llvm::ConstantExpr>(user)) {
4397       if (bitcast->getOpcode() == llvm::Instruction::BitCast)
4398         replaceUsesOfNonProtoConstant(bitcast, newFn);
4399       continue;
4400     }
4401 
4402     // Recognize calls to the function.
4403     llvm::CallBase *callSite = dyn_cast<llvm::CallBase>(user);
4404     if (!callSite) continue;
4405     if (!callSite->isCallee(&*use))
4406       continue;
4407 
4408     // If the return types don't match exactly, then we can't
4409     // transform this call unless it's dead.
4410     if (callSite->getType() != newRetTy && !callSite->use_empty())
4411       continue;
4412 
4413     // Get the call site's attribute list.
4414     SmallVector<llvm::AttributeSet, 8> newArgAttrs;
4415     llvm::AttributeList oldAttrs = callSite->getAttributes();
4416 
4417     // If the function was passed too few arguments, don't transform.
4418     unsigned newNumArgs = newFn->arg_size();
4419     if (callSite->arg_size() < newNumArgs)
4420       continue;
4421 
4422     // If extra arguments were passed, we silently drop them.
4423     // If any of the types mismatch, we don't transform.
4424     unsigned argNo = 0;
4425     bool dontTransform = false;
4426     for (llvm::Argument &A : newFn->args()) {
4427       if (callSite->getArgOperand(argNo)->getType() != A.getType()) {
4428         dontTransform = true;
4429         break;
4430       }
4431 
4432       // Add any parameter attributes.
4433       newArgAttrs.push_back(oldAttrs.getParamAttributes(argNo));
4434       argNo++;
4435     }
4436     if (dontTransform)
4437       continue;
4438 
4439     // Okay, we can transform this.  Create the new call instruction and copy
4440     // over the required information.
4441     newArgs.append(callSite->arg_begin(), callSite->arg_begin() + argNo);
4442 
4443     // Copy over any operand bundles.
4444     callSite->getOperandBundlesAsDefs(newBundles);
4445 
4446     llvm::CallBase *newCall;
4447     if (dyn_cast<llvm::CallInst>(callSite)) {
4448       newCall =
4449           llvm::CallInst::Create(newFn, newArgs, newBundles, "", callSite);
4450     } else {
4451       auto *oldInvoke = cast<llvm::InvokeInst>(callSite);
4452       newCall = llvm::InvokeInst::Create(newFn, oldInvoke->getNormalDest(),
4453                                          oldInvoke->getUnwindDest(), newArgs,
4454                                          newBundles, "", callSite);
4455     }
4456     newArgs.clear(); // for the next iteration
4457 
4458     if (!newCall->getType()->isVoidTy())
4459       newCall->takeName(callSite);
4460     newCall->setAttributes(llvm::AttributeList::get(
4461         newFn->getContext(), oldAttrs.getFnAttributes(),
4462         oldAttrs.getRetAttributes(), newArgAttrs));
4463     newCall->setCallingConv(callSite->getCallingConv());
4464 
4465     // Finally, remove the old call, replacing any uses with the new one.
4466     if (!callSite->use_empty())
4467       callSite->replaceAllUsesWith(newCall);
4468 
4469     // Copy debug location attached to CI.
4470     if (callSite->getDebugLoc())
4471       newCall->setDebugLoc(callSite->getDebugLoc());
4472 
4473     callSite->eraseFromParent();
4474   }
4475 }
4476 
4477 /// ReplaceUsesOfNonProtoTypeWithRealFunction - This function is called when we
4478 /// implement a function with no prototype, e.g. "int foo() {}".  If there are
4479 /// existing call uses of the old function in the module, this adjusts them to
4480 /// call the new function directly.
4481 ///
4482 /// This is not just a cleanup: the always_inline pass requires direct calls to
4483 /// functions to be able to inline them.  If there is a bitcast in the way, it
4484 /// won't inline them.  Instcombine normally deletes these calls, but it isn't
4485 /// run at -O0.
4486 static void ReplaceUsesOfNonProtoTypeWithRealFunction(llvm::GlobalValue *Old,
4487                                                       llvm::Function *NewFn) {
4488   // If we're redefining a global as a function, don't transform it.
4489   if (!isa<llvm::Function>(Old)) return;
4490 
4491   replaceUsesOfNonProtoConstant(Old, NewFn);
4492 }
4493 
4494 void CodeGenModule::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
4495   auto DK = VD->isThisDeclarationADefinition();
4496   if (DK == VarDecl::Definition && VD->hasAttr<DLLImportAttr>())
4497     return;
4498 
4499   TemplateSpecializationKind TSK = VD->getTemplateSpecializationKind();
4500   // If we have a definition, this might be a deferred decl. If the
4501   // instantiation is explicit, make sure we emit it at the end.
4502   if (VD->getDefinition() && TSK == TSK_ExplicitInstantiationDefinition)
4503     GetAddrOfGlobalVar(VD);
4504 
4505   EmitTopLevelDecl(VD);
4506 }
4507 
4508 void CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
4509                                                  llvm::GlobalValue *GV) {
4510   const auto *D = cast<FunctionDecl>(GD.getDecl());
4511 
4512   // Compute the function info and LLVM type.
4513   const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
4514   llvm::FunctionType *Ty = getTypes().GetFunctionType(FI);
4515 
4516   // Get or create the prototype for the function.
4517   if (!GV || (GV->getValueType() != Ty))
4518     GV = cast<llvm::GlobalValue>(GetAddrOfFunction(GD, Ty, /*ForVTable=*/false,
4519                                                    /*DontDefer=*/true,
4520                                                    ForDefinition));
4521 
4522   // Already emitted.
4523   if (!GV->isDeclaration())
4524     return;
4525 
4526   // We need to set linkage and visibility on the function before
4527   // generating code for it because various parts of IR generation
4528   // want to propagate this information down (e.g. to local static
4529   // declarations).
4530   auto *Fn = cast<llvm::Function>(GV);
4531   setFunctionLinkage(GD, Fn);
4532 
4533   // FIXME: this is redundant with part of setFunctionDefinitionAttributes
4534   setGVProperties(Fn, GD);
4535 
4536   MaybeHandleStaticInExternC(D, Fn);
4537 
4538 
4539   maybeSetTrivialComdat(*D, *Fn);
4540 
4541   CodeGenFunction(*this).GenerateCode(GD, Fn, FI);
4542 
4543   setNonAliasAttributes(GD, Fn);
4544   SetLLVMFunctionAttributesForDefinition(D, Fn);
4545 
4546   if (const ConstructorAttr *CA = D->getAttr<ConstructorAttr>())
4547     AddGlobalCtor(Fn, CA->getPriority());
4548   if (const DestructorAttr *DA = D->getAttr<DestructorAttr>())
4549     AddGlobalDtor(Fn, DA->getPriority());
4550   if (D->hasAttr<AnnotateAttr>())
4551     AddGlobalAnnotations(D, Fn);
4552 }
4553 
4554 void CodeGenModule::EmitAliasDefinition(GlobalDecl GD) {
4555   const auto *D = cast<ValueDecl>(GD.getDecl());
4556   const AliasAttr *AA = D->getAttr<AliasAttr>();
4557   assert(AA && "Not an alias?");
4558 
4559   StringRef MangledName = getMangledName(GD);
4560 
4561   if (AA->getAliasee() == MangledName) {
4562     Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
4563     return;
4564   }
4565 
4566   // If there is a definition in the module, then it wins over the alias.
4567   // This is dubious, but allow it to be safe.  Just ignore the alias.
4568   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4569   if (Entry && !Entry->isDeclaration())
4570     return;
4571 
4572   Aliases.push_back(GD);
4573 
4574   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
4575 
4576   // Create a reference to the named value.  This ensures that it is emitted
4577   // if a deferred decl.
4578   llvm::Constant *Aliasee;
4579   llvm::GlobalValue::LinkageTypes LT;
4580   if (isa<llvm::FunctionType>(DeclTy)) {
4581     Aliasee = GetOrCreateLLVMFunction(AA->getAliasee(), DeclTy, GD,
4582                                       /*ForVTable=*/false);
4583     LT = getFunctionLinkage(GD);
4584   } else {
4585     Aliasee = GetOrCreateLLVMGlobal(AA->getAliasee(),
4586                                     llvm::PointerType::getUnqual(DeclTy),
4587                                     /*D=*/nullptr);
4588     LT = getLLVMLinkageVarDefinition(cast<VarDecl>(GD.getDecl()),
4589                                      D->getType().isConstQualified());
4590   }
4591 
4592   // Create the new alias itself, but don't set a name yet.
4593   unsigned AS = Aliasee->getType()->getPointerAddressSpace();
4594   auto *GA =
4595       llvm::GlobalAlias::create(DeclTy, AS, LT, "", Aliasee, &getModule());
4596 
4597   if (Entry) {
4598     if (GA->getAliasee() == Entry) {
4599       Diags.Report(AA->getLocation(), diag::err_cyclic_alias) << 0;
4600       return;
4601     }
4602 
4603     assert(Entry->isDeclaration());
4604 
4605     // If there is a declaration in the module, then we had an extern followed
4606     // by the alias, as in:
4607     //   extern int test6();
4608     //   ...
4609     //   int test6() __attribute__((alias("test7")));
4610     //
4611     // Remove it and replace uses of it with the alias.
4612     GA->takeName(Entry);
4613 
4614     Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GA,
4615                                                           Entry->getType()));
4616     Entry->eraseFromParent();
4617   } else {
4618     GA->setName(MangledName);
4619   }
4620 
4621   // Set attributes which are particular to an alias; this is a
4622   // specialization of the attributes which may be set on a global
4623   // variable/function.
4624   if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakRefAttr>() ||
4625       D->isWeakImported()) {
4626     GA->setLinkage(llvm::Function::WeakAnyLinkage);
4627   }
4628 
4629   if (const auto *VD = dyn_cast<VarDecl>(D))
4630     if (VD->getTLSKind())
4631       setTLSMode(GA, *VD);
4632 
4633   SetCommonAttributes(GD, GA);
4634 }
4635 
4636 void CodeGenModule::emitIFuncDefinition(GlobalDecl GD) {
4637   const auto *D = cast<ValueDecl>(GD.getDecl());
4638   const IFuncAttr *IFA = D->getAttr<IFuncAttr>();
4639   assert(IFA && "Not an ifunc?");
4640 
4641   StringRef MangledName = getMangledName(GD);
4642 
4643   if (IFA->getResolver() == MangledName) {
4644     Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
4645     return;
4646   }
4647 
4648   // Report an error if some definition overrides ifunc.
4649   llvm::GlobalValue *Entry = GetGlobalValue(MangledName);
4650   if (Entry && !Entry->isDeclaration()) {
4651     GlobalDecl OtherGD;
4652     if (lookupRepresentativeDecl(MangledName, OtherGD) &&
4653         DiagnosedConflictingDefinitions.insert(GD).second) {
4654       Diags.Report(D->getLocation(), diag::err_duplicate_mangled_name)
4655           << MangledName;
4656       Diags.Report(OtherGD.getDecl()->getLocation(),
4657                    diag::note_previous_definition);
4658     }
4659     return;
4660   }
4661 
4662   Aliases.push_back(GD);
4663 
4664   llvm::Type *DeclTy = getTypes().ConvertTypeForMem(D->getType());
4665   llvm::Constant *Resolver =
4666       GetOrCreateLLVMFunction(IFA->getResolver(), DeclTy, GD,
4667                               /*ForVTable=*/false);
4668   llvm::GlobalIFunc *GIF =
4669       llvm::GlobalIFunc::create(DeclTy, 0, llvm::Function::ExternalLinkage,
4670                                 "", Resolver, &getModule());
4671   if (Entry) {
4672     if (GIF->getResolver() == Entry) {
4673       Diags.Report(IFA->getLocation(), diag::err_cyclic_alias) << 1;
4674       return;
4675     }
4676     assert(Entry->isDeclaration());
4677 
4678     // If there is a declaration in the module, then we had an extern followed
4679     // by the ifunc, as in:
4680     //   extern int test();
4681     //   ...
4682     //   int test() __attribute__((ifunc("resolver")));
4683     //
4684     // Remove it and replace uses of it with the ifunc.
4685     GIF->takeName(Entry);
4686 
4687     Entry->replaceAllUsesWith(llvm::ConstantExpr::getBitCast(GIF,
4688                                                           Entry->getType()));
4689     Entry->eraseFromParent();
4690   } else
4691     GIF->setName(MangledName);
4692 
4693   SetCommonAttributes(GD, GIF);
4694 }
4695 
4696 llvm::Function *CodeGenModule::getIntrinsic(unsigned IID,
4697                                             ArrayRef<llvm::Type*> Tys) {
4698   return llvm::Intrinsic::getDeclaration(&getModule(), (llvm::Intrinsic::ID)IID,
4699                                          Tys);
4700 }
4701 
4702 static llvm::StringMapEntry<llvm::GlobalVariable *> &
4703 GetConstantCFStringEntry(llvm::StringMap<llvm::GlobalVariable *> &Map,
4704                          const StringLiteral *Literal, bool TargetIsLSB,
4705                          bool &IsUTF16, unsigned &StringLength) {
4706   StringRef String = Literal->getString();
4707   unsigned NumBytes = String.size();
4708 
4709   // Check for simple case.
4710   if (!Literal->containsNonAsciiOrNull()) {
4711     StringLength = NumBytes;
4712     return *Map.insert(std::make_pair(String, nullptr)).first;
4713   }
4714 
4715   // Otherwise, convert the UTF8 literals into a string of shorts.
4716   IsUTF16 = true;
4717 
4718   SmallVector<llvm::UTF16, 128> ToBuf(NumBytes + 1); // +1 for ending nulls.
4719   const llvm::UTF8 *FromPtr = (const llvm::UTF8 *)String.data();
4720   llvm::UTF16 *ToPtr = &ToBuf[0];
4721 
4722   (void)llvm::ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, &ToPtr,
4723                                  ToPtr + NumBytes, llvm::strictConversion);
4724 
4725   // ConvertUTF8toUTF16 returns the length in ToPtr.
4726   StringLength = ToPtr - &ToBuf[0];
4727 
4728   // Add an explicit null.
4729   *ToPtr = 0;
4730   return *Map.insert(std::make_pair(
4731                          StringRef(reinterpret_cast<const char *>(ToBuf.data()),
4732                                    (StringLength + 1) * 2),
4733                          nullptr)).first;
4734 }
4735 
4736 ConstantAddress
4737 CodeGenModule::GetAddrOfConstantCFString(const StringLiteral *Literal) {
4738   unsigned StringLength = 0;
4739   bool isUTF16 = false;
4740   llvm::StringMapEntry<llvm::GlobalVariable *> &Entry =
4741       GetConstantCFStringEntry(CFConstantStringMap, Literal,
4742                                getDataLayout().isLittleEndian(), isUTF16,
4743                                StringLength);
4744 
4745   if (auto *C = Entry.second)
4746     return ConstantAddress(C, CharUnits::fromQuantity(C->getAlignment()));
4747 
4748   llvm::Constant *Zero = llvm::Constant::getNullValue(Int32Ty);
4749   llvm::Constant *Zeros[] = { Zero, Zero };
4750 
4751   const ASTContext &Context = getContext();
4752   const llvm::Triple &Triple = getTriple();
4753 
4754   const auto CFRuntime = getLangOpts().CFRuntime;
4755   const bool IsSwiftABI =
4756       static_cast<unsigned>(CFRuntime) >=
4757       static_cast<unsigned>(LangOptions::CoreFoundationABI::Swift);
4758   const bool IsSwift4_1 = CFRuntime == LangOptions::CoreFoundationABI::Swift4_1;
4759 
4760   // If we don't already have it, get __CFConstantStringClassReference.
4761   if (!CFConstantStringClassRef) {
4762     const char *CFConstantStringClassName = "__CFConstantStringClassReference";
4763     llvm::Type *Ty = getTypes().ConvertType(getContext().IntTy);
4764     Ty = llvm::ArrayType::get(Ty, 0);
4765 
4766     switch (CFRuntime) {
4767     default: break;
4768     case LangOptions::CoreFoundationABI::Swift: LLVM_FALLTHROUGH;
4769     case LangOptions::CoreFoundationABI::Swift5_0:
4770       CFConstantStringClassName =
4771           Triple.isOSDarwin() ? "$s15SwiftFoundation19_NSCFConstantStringCN"
4772                               : "$s10Foundation19_NSCFConstantStringCN";
4773       Ty = IntPtrTy;
4774       break;
4775     case LangOptions::CoreFoundationABI::Swift4_2:
4776       CFConstantStringClassName =
4777           Triple.isOSDarwin() ? "$S15SwiftFoundation19_NSCFConstantStringCN"
4778                               : "$S10Foundation19_NSCFConstantStringCN";
4779       Ty = IntPtrTy;
4780       break;
4781     case LangOptions::CoreFoundationABI::Swift4_1:
4782       CFConstantStringClassName =
4783           Triple.isOSDarwin() ? "__T015SwiftFoundation19_NSCFConstantStringCN"
4784                               : "__T010Foundation19_NSCFConstantStringCN";
4785       Ty = IntPtrTy;
4786       break;
4787     }
4788 
4789     llvm::Constant *C = CreateRuntimeVariable(Ty, CFConstantStringClassName);
4790 
4791     if (Triple.isOSBinFormatELF() || Triple.isOSBinFormatCOFF()) {
4792       llvm::GlobalValue *GV = nullptr;
4793 
4794       if ((GV = dyn_cast<llvm::GlobalValue>(C))) {
4795         IdentifierInfo &II = Context.Idents.get(GV->getName());
4796         TranslationUnitDecl *TUDecl = Context.getTranslationUnitDecl();
4797         DeclContext *DC = TranslationUnitDecl::castToDeclContext(TUDecl);
4798 
4799         const VarDecl *VD = nullptr;
4800         for (const auto &Result : DC->lookup(&II))
4801           if ((VD = dyn_cast<VarDecl>(Result)))
4802             break;
4803 
4804         if (Triple.isOSBinFormatELF()) {
4805           if (!VD)
4806             GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
4807         } else {
4808           GV->setLinkage(llvm::GlobalValue::ExternalLinkage);
4809           if (!VD || !VD->hasAttr<DLLExportAttr>())
4810             GV->setDLLStorageClass(llvm::GlobalValue::DLLImportStorageClass);
4811           else
4812             GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
4813         }
4814 
4815         setDSOLocal(GV);
4816       }
4817     }
4818 
4819     // Decay array -> ptr
4820     CFConstantStringClassRef =
4821         IsSwiftABI ? llvm::ConstantExpr::getPtrToInt(C, Ty)
4822                    : llvm::ConstantExpr::getGetElementPtr(Ty, C, Zeros);
4823   }
4824 
4825   QualType CFTy = Context.getCFConstantStringType();
4826 
4827   auto *STy = cast<llvm::StructType>(getTypes().ConvertType(CFTy));
4828 
4829   ConstantInitBuilder Builder(*this);
4830   auto Fields = Builder.beginStruct(STy);
4831 
4832   // Class pointer.
4833   Fields.add(cast<llvm::ConstantExpr>(CFConstantStringClassRef));
4834 
4835   // Flags.
4836   if (IsSwiftABI) {
4837     Fields.addInt(IntPtrTy, IsSwift4_1 ? 0x05 : 0x01);
4838     Fields.addInt(Int64Ty, isUTF16 ? 0x07d0 : 0x07c8);
4839   } else {
4840     Fields.addInt(IntTy, isUTF16 ? 0x07d0 : 0x07C8);
4841   }
4842 
4843   // String pointer.
4844   llvm::Constant *C = nullptr;
4845   if (isUTF16) {
4846     auto Arr = llvm::makeArrayRef(
4847         reinterpret_cast<uint16_t *>(const_cast<char *>(Entry.first().data())),
4848         Entry.first().size() / 2);
4849     C = llvm::ConstantDataArray::get(VMContext, Arr);
4850   } else {
4851     C = llvm::ConstantDataArray::getString(VMContext, Entry.first());
4852   }
4853 
4854   // Note: -fwritable-strings doesn't make the backing store strings of
4855   // CFStrings writable. (See <rdar://problem/10657500>)
4856   auto *GV =
4857       new llvm::GlobalVariable(getModule(), C->getType(), /*isConstant=*/true,
4858                                llvm::GlobalValue::PrivateLinkage, C, ".str");
4859   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
4860   // Don't enforce the target's minimum global alignment, since the only use
4861   // of the string is via this class initializer.
4862   CharUnits Align = isUTF16 ? Context.getTypeAlignInChars(Context.ShortTy)
4863                             : Context.getTypeAlignInChars(Context.CharTy);
4864   GV->setAlignment(Align.getAsAlign());
4865 
4866   // FIXME: We set the section explicitly to avoid a bug in ld64 224.1.
4867   // Without it LLVM can merge the string with a non unnamed_addr one during
4868   // LTO.  Doing that changes the section it ends in, which surprises ld64.
4869   if (Triple.isOSBinFormatMachO())
4870     GV->setSection(isUTF16 ? "__TEXT,__ustring"
4871                            : "__TEXT,__cstring,cstring_literals");
4872   // Make sure the literal ends up in .rodata to allow for safe ICF and for
4873   // the static linker to adjust permissions to read-only later on.
4874   else if (Triple.isOSBinFormatELF())
4875     GV->setSection(".rodata");
4876 
4877   // String.
4878   llvm::Constant *Str =
4879       llvm::ConstantExpr::getGetElementPtr(GV->getValueType(), GV, Zeros);
4880 
4881   if (isUTF16)
4882     // Cast the UTF16 string to the correct type.
4883     Str = llvm::ConstantExpr::getBitCast(Str, Int8PtrTy);
4884   Fields.add(Str);
4885 
4886   // String length.
4887   llvm::IntegerType *LengthTy =
4888       llvm::IntegerType::get(getModule().getContext(),
4889                              Context.getTargetInfo().getLongWidth());
4890   if (IsSwiftABI) {
4891     if (CFRuntime == LangOptions::CoreFoundationABI::Swift4_1 ||
4892         CFRuntime == LangOptions::CoreFoundationABI::Swift4_2)
4893       LengthTy = Int32Ty;
4894     else
4895       LengthTy = IntPtrTy;
4896   }
4897   Fields.addInt(LengthTy, StringLength);
4898 
4899   // Swift ABI requires 8-byte alignment to ensure that the _Atomic(uint64_t) is
4900   // properly aligned on 32-bit platforms.
4901   CharUnits Alignment =
4902       IsSwiftABI ? Context.toCharUnitsFromBits(64) : getPointerAlign();
4903 
4904   // The struct.
4905   GV = Fields.finishAndCreateGlobal("_unnamed_cfstring_", Alignment,
4906                                     /*isConstant=*/false,
4907                                     llvm::GlobalVariable::PrivateLinkage);
4908   GV->addAttribute("objc_arc_inert");
4909   switch (Triple.getObjectFormat()) {
4910   case llvm::Triple::UnknownObjectFormat:
4911     llvm_unreachable("unknown file format");
4912   case llvm::Triple::XCOFF:
4913     llvm_unreachable("XCOFF is not yet implemented");
4914   case llvm::Triple::COFF:
4915   case llvm::Triple::ELF:
4916   case llvm::Triple::Wasm:
4917     GV->setSection("cfstring");
4918     break;
4919   case llvm::Triple::MachO:
4920     GV->setSection("__DATA,__cfstring");
4921     break;
4922   }
4923   Entry.second = GV;
4924 
4925   return ConstantAddress(GV, Alignment);
4926 }
4927 
4928 bool CodeGenModule::getExpressionLocationsEnabled() const {
4929   return !CodeGenOpts.EmitCodeView || CodeGenOpts.DebugColumnInfo;
4930 }
4931 
4932 QualType CodeGenModule::getObjCFastEnumerationStateType() {
4933   if (ObjCFastEnumerationStateType.isNull()) {
4934     RecordDecl *D = Context.buildImplicitRecord("__objcFastEnumerationState");
4935     D->startDefinition();
4936 
4937     QualType FieldTypes[] = {
4938       Context.UnsignedLongTy,
4939       Context.getPointerType(Context.getObjCIdType()),
4940       Context.getPointerType(Context.UnsignedLongTy),
4941       Context.getConstantArrayType(Context.UnsignedLongTy,
4942                            llvm::APInt(32, 5), nullptr, ArrayType::Normal, 0)
4943     };
4944 
4945     for (size_t i = 0; i < 4; ++i) {
4946       FieldDecl *Field = FieldDecl::Create(Context,
4947                                            D,
4948                                            SourceLocation(),
4949                                            SourceLocation(), nullptr,
4950                                            FieldTypes[i], /*TInfo=*/nullptr,
4951                                            /*BitWidth=*/nullptr,
4952                                            /*Mutable=*/false,
4953                                            ICIS_NoInit);
4954       Field->setAccess(AS_public);
4955       D->addDecl(Field);
4956     }
4957 
4958     D->completeDefinition();
4959     ObjCFastEnumerationStateType = Context.getTagDeclType(D);
4960   }
4961 
4962   return ObjCFastEnumerationStateType;
4963 }
4964 
4965 llvm::Constant *
4966 CodeGenModule::GetConstantArrayFromStringLiteral(const StringLiteral *E) {
4967   assert(!E->getType()->isPointerType() && "Strings are always arrays");
4968 
4969   // Don't emit it as the address of the string, emit the string data itself
4970   // as an inline array.
4971   if (E->getCharByteWidth() == 1) {
4972     SmallString<64> Str(E->getString());
4973 
4974     // Resize the string to the right size, which is indicated by its type.
4975     const ConstantArrayType *CAT = Context.getAsConstantArrayType(E->getType());
4976     Str.resize(CAT->getSize().getZExtValue());
4977     return llvm::ConstantDataArray::getString(VMContext, Str, false);
4978   }
4979 
4980   auto *AType = cast<llvm::ArrayType>(getTypes().ConvertType(E->getType()));
4981   llvm::Type *ElemTy = AType->getElementType();
4982   unsigned NumElements = AType->getNumElements();
4983 
4984   // Wide strings have either 2-byte or 4-byte elements.
4985   if (ElemTy->getPrimitiveSizeInBits() == 16) {
4986     SmallVector<uint16_t, 32> Elements;
4987     Elements.reserve(NumElements);
4988 
4989     for(unsigned i = 0, e = E->getLength(); i != e; ++i)
4990       Elements.push_back(E->getCodeUnit(i));
4991     Elements.resize(NumElements);
4992     return llvm::ConstantDataArray::get(VMContext, Elements);
4993   }
4994 
4995   assert(ElemTy->getPrimitiveSizeInBits() == 32);
4996   SmallVector<uint32_t, 32> Elements;
4997   Elements.reserve(NumElements);
4998 
4999   for(unsigned i = 0, e = E->getLength(); i != e; ++i)
5000     Elements.push_back(E->getCodeUnit(i));
5001   Elements.resize(NumElements);
5002   return llvm::ConstantDataArray::get(VMContext, Elements);
5003 }
5004 
5005 static llvm::GlobalVariable *
5006 GenerateStringLiteral(llvm::Constant *C, llvm::GlobalValue::LinkageTypes LT,
5007                       CodeGenModule &CGM, StringRef GlobalName,
5008                       CharUnits Alignment) {
5009   unsigned AddrSpace = CGM.getContext().getTargetAddressSpace(
5010       CGM.getStringLiteralAddressSpace());
5011 
5012   llvm::Module &M = CGM.getModule();
5013   // Create a global variable for this string
5014   auto *GV = new llvm::GlobalVariable(
5015       M, C->getType(), !CGM.getLangOpts().WritableStrings, LT, C, GlobalName,
5016       nullptr, llvm::GlobalVariable::NotThreadLocal, AddrSpace);
5017   GV->setAlignment(Alignment.getAsAlign());
5018   GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
5019   if (GV->isWeakForLinker()) {
5020     assert(CGM.supportsCOMDAT() && "Only COFF uses weak string literals");
5021     GV->setComdat(M.getOrInsertComdat(GV->getName()));
5022   }
5023   CGM.setDSOLocal(GV);
5024 
5025   return GV;
5026 }
5027 
5028 /// GetAddrOfConstantStringFromLiteral - Return a pointer to a
5029 /// constant array for the given string literal.
5030 ConstantAddress
5031 CodeGenModule::GetAddrOfConstantStringFromLiteral(const StringLiteral *S,
5032                                                   StringRef Name) {
5033   CharUnits Alignment = getContext().getAlignOfGlobalVarInChars(S->getType());
5034 
5035   llvm::Constant *C = GetConstantArrayFromStringLiteral(S);
5036   llvm::GlobalVariable **Entry = nullptr;
5037   if (!LangOpts.WritableStrings) {
5038     Entry = &ConstantStringMap[C];
5039     if (auto GV = *Entry) {
5040       if (Alignment.getQuantity() > GV->getAlignment())
5041         GV->setAlignment(Alignment.getAsAlign());
5042       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
5043                              Alignment);
5044     }
5045   }
5046 
5047   SmallString<256> MangledNameBuffer;
5048   StringRef GlobalVariableName;
5049   llvm::GlobalValue::LinkageTypes LT;
5050 
5051   // Mangle the string literal if that's how the ABI merges duplicate strings.
5052   // Don't do it if they are writable, since we don't want writes in one TU to
5053   // affect strings in another.
5054   if (getCXXABI().getMangleContext().shouldMangleStringLiteral(S) &&
5055       !LangOpts.WritableStrings) {
5056     llvm::raw_svector_ostream Out(MangledNameBuffer);
5057     getCXXABI().getMangleContext().mangleStringLiteral(S, Out);
5058     LT = llvm::GlobalValue::LinkOnceODRLinkage;
5059     GlobalVariableName = MangledNameBuffer;
5060   } else {
5061     LT = llvm::GlobalValue::PrivateLinkage;
5062     GlobalVariableName = Name;
5063   }
5064 
5065   auto GV = GenerateStringLiteral(C, LT, *this, GlobalVariableName, Alignment);
5066   if (Entry)
5067     *Entry = GV;
5068 
5069   SanitizerMD->reportGlobalToASan(GV, S->getStrTokenLoc(0), "<string literal>",
5070                                   QualType());
5071 
5072   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
5073                          Alignment);
5074 }
5075 
5076 /// GetAddrOfConstantStringFromObjCEncode - Return a pointer to a constant
5077 /// array for the given ObjCEncodeExpr node.
5078 ConstantAddress
5079 CodeGenModule::GetAddrOfConstantStringFromObjCEncode(const ObjCEncodeExpr *E) {
5080   std::string Str;
5081   getContext().getObjCEncodingForType(E->getEncodedType(), Str);
5082 
5083   return GetAddrOfConstantCString(Str);
5084 }
5085 
5086 /// GetAddrOfConstantCString - Returns a pointer to a character array containing
5087 /// the literal and a terminating '\0' character.
5088 /// The result has pointer to array type.
5089 ConstantAddress CodeGenModule::GetAddrOfConstantCString(
5090     const std::string &Str, const char *GlobalName) {
5091   StringRef StrWithNull(Str.c_str(), Str.size() + 1);
5092   CharUnits Alignment =
5093     getContext().getAlignOfGlobalVarInChars(getContext().CharTy);
5094 
5095   llvm::Constant *C =
5096       llvm::ConstantDataArray::getString(getLLVMContext(), StrWithNull, false);
5097 
5098   // Don't share any string literals if strings aren't constant.
5099   llvm::GlobalVariable **Entry = nullptr;
5100   if (!LangOpts.WritableStrings) {
5101     Entry = &ConstantStringMap[C];
5102     if (auto GV = *Entry) {
5103       if (Alignment.getQuantity() > GV->getAlignment())
5104         GV->setAlignment(Alignment.getAsAlign());
5105       return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
5106                              Alignment);
5107     }
5108   }
5109 
5110   // Get the default prefix if a name wasn't specified.
5111   if (!GlobalName)
5112     GlobalName = ".str";
5113   // Create a global variable for this.
5114   auto GV = GenerateStringLiteral(C, llvm::GlobalValue::PrivateLinkage, *this,
5115                                   GlobalName, Alignment);
5116   if (Entry)
5117     *Entry = GV;
5118 
5119   return ConstantAddress(castStringLiteralToDefaultAddressSpace(*this, GV),
5120                          Alignment);
5121 }
5122 
5123 ConstantAddress CodeGenModule::GetAddrOfGlobalTemporary(
5124     const MaterializeTemporaryExpr *E, const Expr *Init) {
5125   assert((E->getStorageDuration() == SD_Static ||
5126           E->getStorageDuration() == SD_Thread) && "not a global temporary");
5127   const auto *VD = cast<VarDecl>(E->getExtendingDecl());
5128 
5129   // If we're not materializing a subobject of the temporary, keep the
5130   // cv-qualifiers from the type of the MaterializeTemporaryExpr.
5131   QualType MaterializedType = Init->getType();
5132   if (Init == E->getSubExpr())
5133     MaterializedType = E->getType();
5134 
5135   CharUnits Align = getContext().getTypeAlignInChars(MaterializedType);
5136 
5137   if (llvm::Constant *Slot = MaterializedGlobalTemporaryMap[E])
5138     return ConstantAddress(Slot, Align);
5139 
5140   // FIXME: If an externally-visible declaration extends multiple temporaries,
5141   // we need to give each temporary the same name in every translation unit (and
5142   // we also need to make the temporaries externally-visible).
5143   SmallString<256> Name;
5144   llvm::raw_svector_ostream Out(Name);
5145   getCXXABI().getMangleContext().mangleReferenceTemporary(
5146       VD, E->getManglingNumber(), Out);
5147 
5148   APValue *Value = nullptr;
5149   if (E->getStorageDuration() == SD_Static && VD && VD->evaluateValue()) {
5150     // If the initializer of the extending declaration is a constant
5151     // initializer, we should have a cached constant initializer for this
5152     // temporary. Note that this might have a different value from the value
5153     // computed by evaluating the initializer if the surrounding constant
5154     // expression modifies the temporary.
5155     Value = E->getOrCreateValue(false);
5156   }
5157 
5158   // Try evaluating it now, it might have a constant initializer.
5159   Expr::EvalResult EvalResult;
5160   if (!Value && Init->EvaluateAsRValue(EvalResult, getContext()) &&
5161       !EvalResult.hasSideEffects())
5162     Value = &EvalResult.Val;
5163 
5164   LangAS AddrSpace =
5165       VD ? GetGlobalVarAddressSpace(VD) : MaterializedType.getAddressSpace();
5166 
5167   Optional<ConstantEmitter> emitter;
5168   llvm::Constant *InitialValue = nullptr;
5169   bool Constant = false;
5170   llvm::Type *Type;
5171   if (Value) {
5172     // The temporary has a constant initializer, use it.
5173     emitter.emplace(*this);
5174     InitialValue = emitter->emitForInitializer(*Value, AddrSpace,
5175                                                MaterializedType);
5176     Constant = isTypeConstant(MaterializedType, /*ExcludeCtor*/Value);
5177     Type = InitialValue->getType();
5178   } else {
5179     // No initializer, the initialization will be provided when we
5180     // initialize the declaration which performed lifetime extension.
5181     Type = getTypes().ConvertTypeForMem(MaterializedType);
5182   }
5183 
5184   // Create a global variable for this lifetime-extended temporary.
5185   llvm::GlobalValue::LinkageTypes Linkage =
5186       getLLVMLinkageVarDefinition(VD, Constant);
5187   if (Linkage == llvm::GlobalVariable::ExternalLinkage) {
5188     const VarDecl *InitVD;
5189     if (VD->isStaticDataMember() && VD->getAnyInitializer(InitVD) &&
5190         isa<CXXRecordDecl>(InitVD->getLexicalDeclContext())) {
5191       // Temporaries defined inside a class get linkonce_odr linkage because the
5192       // class can be defined in multiple translation units.
5193       Linkage = llvm::GlobalVariable::LinkOnceODRLinkage;
5194     } else {
5195       // There is no need for this temporary to have external linkage if the
5196       // VarDecl has external linkage.
5197       Linkage = llvm::GlobalVariable::InternalLinkage;
5198     }
5199   }
5200   auto TargetAS = getContext().getTargetAddressSpace(AddrSpace);
5201   auto *GV = new llvm::GlobalVariable(
5202       getModule(), Type, Constant, Linkage, InitialValue, Name.c_str(),
5203       /*InsertBefore=*/nullptr, llvm::GlobalVariable::NotThreadLocal, TargetAS);
5204   if (emitter) emitter->finalize(GV);
5205   setGVProperties(GV, VD);
5206   GV->setAlignment(Align.getAsAlign());
5207   if (supportsCOMDAT() && GV->isWeakForLinker())
5208     GV->setComdat(TheModule.getOrInsertComdat(GV->getName()));
5209   if (VD->getTLSKind())
5210     setTLSMode(GV, *VD);
5211   llvm::Constant *CV = GV;
5212   if (AddrSpace != LangAS::Default)
5213     CV = getTargetCodeGenInfo().performAddrSpaceCast(
5214         *this, GV, AddrSpace, LangAS::Default,
5215         Type->getPointerTo(
5216             getContext().getTargetAddressSpace(LangAS::Default)));
5217   MaterializedGlobalTemporaryMap[E] = CV;
5218   return ConstantAddress(CV, Align);
5219 }
5220 
5221 /// EmitObjCPropertyImplementations - Emit information for synthesized
5222 /// properties for an implementation.
5223 void CodeGenModule::EmitObjCPropertyImplementations(const
5224                                                     ObjCImplementationDecl *D) {
5225   for (const auto *PID : D->property_impls()) {
5226     // Dynamic is just for type-checking.
5227     if (PID->getPropertyImplementation() == ObjCPropertyImplDecl::Synthesize) {
5228       ObjCPropertyDecl *PD = PID->getPropertyDecl();
5229 
5230       // Determine which methods need to be implemented, some may have
5231       // been overridden. Note that ::isPropertyAccessor is not the method
5232       // we want, that just indicates if the decl came from a
5233       // property. What we want to know is if the method is defined in
5234       // this implementation.
5235       auto *Getter = PID->getGetterMethodDecl();
5236       if (!Getter || Getter->isSynthesizedAccessorStub())
5237         CodeGenFunction(*this).GenerateObjCGetter(
5238             const_cast<ObjCImplementationDecl *>(D), PID);
5239       auto *Setter = PID->getSetterMethodDecl();
5240       if (!PD->isReadOnly() && (!Setter || Setter->isSynthesizedAccessorStub()))
5241         CodeGenFunction(*this).GenerateObjCSetter(
5242                                  const_cast<ObjCImplementationDecl *>(D), PID);
5243     }
5244   }
5245 }
5246 
5247 static bool needsDestructMethod(ObjCImplementationDecl *impl) {
5248   const ObjCInterfaceDecl *iface = impl->getClassInterface();
5249   for (const ObjCIvarDecl *ivar = iface->all_declared_ivar_begin();
5250        ivar; ivar = ivar->getNextIvar())
5251     if (ivar->getType().isDestructedType())
5252       return true;
5253 
5254   return false;
5255 }
5256 
5257 static bool AllTrivialInitializers(CodeGenModule &CGM,
5258                                    ObjCImplementationDecl *D) {
5259   CodeGenFunction CGF(CGM);
5260   for (ObjCImplementationDecl::init_iterator B = D->init_begin(),
5261        E = D->init_end(); B != E; ++B) {
5262     CXXCtorInitializer *CtorInitExp = *B;
5263     Expr *Init = CtorInitExp->getInit();
5264     if (!CGF.isTrivialInitializer(Init))
5265       return false;
5266   }
5267   return true;
5268 }
5269 
5270 /// EmitObjCIvarInitializations - Emit information for ivar initialization
5271 /// for an implementation.
5272 void CodeGenModule::EmitObjCIvarInitializations(ObjCImplementationDecl *D) {
5273   // We might need a .cxx_destruct even if we don't have any ivar initializers.
5274   if (needsDestructMethod(D)) {
5275     IdentifierInfo *II = &getContext().Idents.get(".cxx_destruct");
5276     Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
5277     ObjCMethodDecl *DTORMethod = ObjCMethodDecl::Create(
5278         getContext(), D->getLocation(), D->getLocation(), cxxSelector,
5279         getContext().VoidTy, nullptr, D,
5280         /*isInstance=*/true, /*isVariadic=*/false,
5281         /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
5282         /*isImplicitlyDeclared=*/true,
5283         /*isDefined=*/false, ObjCMethodDecl::Required);
5284     D->addInstanceMethod(DTORMethod);
5285     CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, DTORMethod, false);
5286     D->setHasDestructors(true);
5287   }
5288 
5289   // If the implementation doesn't have any ivar initializers, we don't need
5290   // a .cxx_construct.
5291   if (D->getNumIvarInitializers() == 0 ||
5292       AllTrivialInitializers(*this, D))
5293     return;
5294 
5295   IdentifierInfo *II = &getContext().Idents.get(".cxx_construct");
5296   Selector cxxSelector = getContext().Selectors.getSelector(0, &II);
5297   // The constructor returns 'self'.
5298   ObjCMethodDecl *CTORMethod = ObjCMethodDecl::Create(
5299       getContext(), D->getLocation(), D->getLocation(), cxxSelector,
5300       getContext().getObjCIdType(), nullptr, D, /*isInstance=*/true,
5301       /*isVariadic=*/false,
5302       /*isPropertyAccessor=*/true, /*isSynthesizedAccessorStub=*/false,
5303       /*isImplicitlyDeclared=*/true,
5304       /*isDefined=*/false, ObjCMethodDecl::Required);
5305   D->addInstanceMethod(CTORMethod);
5306   CodeGenFunction(*this).GenerateObjCCtorDtorMethod(D, CTORMethod, true);
5307   D->setHasNonZeroConstructors(true);
5308 }
5309 
5310 // EmitLinkageSpec - Emit all declarations in a linkage spec.
5311 void CodeGenModule::EmitLinkageSpec(const LinkageSpecDecl *LSD) {
5312   if (LSD->getLanguage() != LinkageSpecDecl::lang_c &&
5313       LSD->getLanguage() != LinkageSpecDecl::lang_cxx) {
5314     ErrorUnsupported(LSD, "linkage spec");
5315     return;
5316   }
5317 
5318   EmitDeclContext(LSD);
5319 }
5320 
5321 void CodeGenModule::EmitDeclContext(const DeclContext *DC) {
5322   for (auto *I : DC->decls()) {
5323     // Unlike other DeclContexts, the contents of an ObjCImplDecl at TU scope
5324     // are themselves considered "top-level", so EmitTopLevelDecl on an
5325     // ObjCImplDecl does not recursively visit them. We need to do that in
5326     // case they're nested inside another construct (LinkageSpecDecl /
5327     // ExportDecl) that does stop them from being considered "top-level".
5328     if (auto *OID = dyn_cast<ObjCImplDecl>(I)) {
5329       for (auto *M : OID->methods())
5330         EmitTopLevelDecl(M);
5331     }
5332 
5333     EmitTopLevelDecl(I);
5334   }
5335 }
5336 
5337 /// EmitTopLevelDecl - Emit code for a single top level declaration.
5338 void CodeGenModule::EmitTopLevelDecl(Decl *D) {
5339   // Ignore dependent declarations.
5340   if (D->isTemplated())
5341     return;
5342 
5343   // Consteval function shouldn't be emitted.
5344   if (auto *FD = dyn_cast<FunctionDecl>(D))
5345     if (FD->isConsteval())
5346       return;
5347 
5348   switch (D->getKind()) {
5349   case Decl::CXXConversion:
5350   case Decl::CXXMethod:
5351   case Decl::Function:
5352     EmitGlobal(cast<FunctionDecl>(D));
5353     // Always provide some coverage mapping
5354     // even for the functions that aren't emitted.
5355     AddDeferredUnusedCoverageMapping(D);
5356     break;
5357 
5358   case Decl::CXXDeductionGuide:
5359     // Function-like, but does not result in code emission.
5360     break;
5361 
5362   case Decl::Var:
5363   case Decl::Decomposition:
5364   case Decl::VarTemplateSpecialization:
5365     EmitGlobal(cast<VarDecl>(D));
5366     if (auto *DD = dyn_cast<DecompositionDecl>(D))
5367       for (auto *B : DD->bindings())
5368         if (auto *HD = B->getHoldingVar())
5369           EmitGlobal(HD);
5370     break;
5371 
5372   // Indirect fields from global anonymous structs and unions can be
5373   // ignored; only the actual variable requires IR gen support.
5374   case Decl::IndirectField:
5375     break;
5376 
5377   // C++ Decls
5378   case Decl::Namespace:
5379     EmitDeclContext(cast<NamespaceDecl>(D));
5380     break;
5381   case Decl::ClassTemplateSpecialization: {
5382     const auto *Spec = cast<ClassTemplateSpecializationDecl>(D);
5383     if (CGDebugInfo *DI = getModuleDebugInfo())
5384       if (Spec->getSpecializationKind() ==
5385               TSK_ExplicitInstantiationDefinition &&
5386           Spec->hasDefinition())
5387         DI->completeTemplateDefinition(*Spec);
5388   } LLVM_FALLTHROUGH;
5389   case Decl::CXXRecord:
5390     if (CGDebugInfo *DI = getModuleDebugInfo())
5391       if (auto *ES = D->getASTContext().getExternalSource())
5392         if (ES->hasExternalDefinitions(D) == ExternalASTSource::EK_Never)
5393           DI->completeUnusedClass(cast<CXXRecordDecl>(*D));
5394     // Emit any static data members, they may be definitions.
5395     for (auto *I : cast<CXXRecordDecl>(D)->decls())
5396       if (isa<VarDecl>(I) || isa<CXXRecordDecl>(I))
5397         EmitTopLevelDecl(I);
5398     break;
5399     // No code generation needed.
5400   case Decl::UsingShadow:
5401   case Decl::ClassTemplate:
5402   case Decl::VarTemplate:
5403   case Decl::Concept:
5404   case Decl::VarTemplatePartialSpecialization:
5405   case Decl::FunctionTemplate:
5406   case Decl::TypeAliasTemplate:
5407   case Decl::Block:
5408   case Decl::Empty:
5409   case Decl::Binding:
5410     break;
5411   case Decl::Using:          // using X; [C++]
5412     if (CGDebugInfo *DI = getModuleDebugInfo())
5413         DI->EmitUsingDecl(cast<UsingDecl>(*D));
5414     break;
5415   case Decl::NamespaceAlias:
5416     if (CGDebugInfo *DI = getModuleDebugInfo())
5417         DI->EmitNamespaceAlias(cast<NamespaceAliasDecl>(*D));
5418     break;
5419   case Decl::UsingDirective: // using namespace X; [C++]
5420     if (CGDebugInfo *DI = getModuleDebugInfo())
5421       DI->EmitUsingDirective(cast<UsingDirectiveDecl>(*D));
5422     break;
5423   case Decl::CXXConstructor:
5424     getCXXABI().EmitCXXConstructors(cast<CXXConstructorDecl>(D));
5425     break;
5426   case Decl::CXXDestructor:
5427     getCXXABI().EmitCXXDestructors(cast<CXXDestructorDecl>(D));
5428     break;
5429 
5430   case Decl::StaticAssert:
5431     // Nothing to do.
5432     break;
5433 
5434   // Objective-C Decls
5435 
5436   // Forward declarations, no (immediate) code generation.
5437   case Decl::ObjCInterface:
5438   case Decl::ObjCCategory:
5439     break;
5440 
5441   case Decl::ObjCProtocol: {
5442     auto *Proto = cast<ObjCProtocolDecl>(D);
5443     if (Proto->isThisDeclarationADefinition())
5444       ObjCRuntime->GenerateProtocol(Proto);
5445     break;
5446   }
5447 
5448   case Decl::ObjCCategoryImpl:
5449     // Categories have properties but don't support synthesize so we
5450     // can ignore them here.
5451     ObjCRuntime->GenerateCategory(cast<ObjCCategoryImplDecl>(D));
5452     break;
5453 
5454   case Decl::ObjCImplementation: {
5455     auto *OMD = cast<ObjCImplementationDecl>(D);
5456     EmitObjCPropertyImplementations(OMD);
5457     EmitObjCIvarInitializations(OMD);
5458     ObjCRuntime->GenerateClass(OMD);
5459     // Emit global variable debug information.
5460     if (CGDebugInfo *DI = getModuleDebugInfo())
5461       if (getCodeGenOpts().hasReducedDebugInfo())
5462         DI->getOrCreateInterfaceType(getContext().getObjCInterfaceType(
5463             OMD->getClassInterface()), OMD->getLocation());
5464     break;
5465   }
5466   case Decl::ObjCMethod: {
5467     auto *OMD = cast<ObjCMethodDecl>(D);
5468     // If this is not a prototype, emit the body.
5469     if (OMD->getBody())
5470       CodeGenFunction(*this).GenerateObjCMethod(OMD);
5471     break;
5472   }
5473   case Decl::ObjCCompatibleAlias:
5474     ObjCRuntime->RegisterAlias(cast<ObjCCompatibleAliasDecl>(D));
5475     break;
5476 
5477   case Decl::PragmaComment: {
5478     const auto *PCD = cast<PragmaCommentDecl>(D);
5479     switch (PCD->getCommentKind()) {
5480     case PCK_Unknown:
5481       llvm_unreachable("unexpected pragma comment kind");
5482     case PCK_Linker:
5483       AppendLinkerOptions(PCD->getArg());
5484       break;
5485     case PCK_Lib:
5486         AddDependentLib(PCD->getArg());
5487       break;
5488     case PCK_Compiler:
5489     case PCK_ExeStr:
5490     case PCK_User:
5491       break; // We ignore all of these.
5492     }
5493     break;
5494   }
5495 
5496   case Decl::PragmaDetectMismatch: {
5497     const auto *PDMD = cast<PragmaDetectMismatchDecl>(D);
5498     AddDetectMismatch(PDMD->getName(), PDMD->getValue());
5499     break;
5500   }
5501 
5502   case Decl::LinkageSpec:
5503     EmitLinkageSpec(cast<LinkageSpecDecl>(D));
5504     break;
5505 
5506   case Decl::FileScopeAsm: {
5507     // File-scope asm is ignored during device-side CUDA compilation.
5508     if (LangOpts.CUDA && LangOpts.CUDAIsDevice)
5509       break;
5510     // File-scope asm is ignored during device-side OpenMP compilation.
5511     if (LangOpts.OpenMPIsDevice)
5512       break;
5513     auto *AD = cast<FileScopeAsmDecl>(D);
5514     getModule().appendModuleInlineAsm(AD->getAsmString()->getString());
5515     break;
5516   }
5517 
5518   case Decl::Import: {
5519     auto *Import = cast<ImportDecl>(D);
5520 
5521     // If we've already imported this module, we're done.
5522     if (!ImportedModules.insert(Import->getImportedModule()))
5523       break;
5524 
5525     // Emit debug information for direct imports.
5526     if (!Import->getImportedOwningModule()) {
5527       if (CGDebugInfo *DI = getModuleDebugInfo())
5528         DI->EmitImportDecl(*Import);
5529     }
5530 
5531     // Find all of the submodules and emit the module initializers.
5532     llvm::SmallPtrSet<clang::Module *, 16> Visited;
5533     SmallVector<clang::Module *, 16> Stack;
5534     Visited.insert(Import->getImportedModule());
5535     Stack.push_back(Import->getImportedModule());
5536 
5537     while (!Stack.empty()) {
5538       clang::Module *Mod = Stack.pop_back_val();
5539       if (!EmittedModuleInitializers.insert(Mod).second)
5540         continue;
5541 
5542       for (auto *D : Context.getModuleInitializers(Mod))
5543         EmitTopLevelDecl(D);
5544 
5545       // Visit the submodules of this module.
5546       for (clang::Module::submodule_iterator Sub = Mod->submodule_begin(),
5547                                              SubEnd = Mod->submodule_end();
5548            Sub != SubEnd; ++Sub) {
5549         // Skip explicit children; they need to be explicitly imported to emit
5550         // the initializers.
5551         if ((*Sub)->IsExplicit)
5552           continue;
5553 
5554         if (Visited.insert(*Sub).second)
5555           Stack.push_back(*Sub);
5556       }
5557     }
5558     break;
5559   }
5560 
5561   case Decl::Export:
5562     EmitDeclContext(cast<ExportDecl>(D));
5563     break;
5564 
5565   case Decl::OMPThreadPrivate:
5566     EmitOMPThreadPrivateDecl(cast<OMPThreadPrivateDecl>(D));
5567     break;
5568 
5569   case Decl::OMPAllocate:
5570     break;
5571 
5572   case Decl::OMPDeclareReduction:
5573     EmitOMPDeclareReduction(cast<OMPDeclareReductionDecl>(D));
5574     break;
5575 
5576   case Decl::OMPDeclareMapper:
5577     EmitOMPDeclareMapper(cast<OMPDeclareMapperDecl>(D));
5578     break;
5579 
5580   case Decl::OMPRequires:
5581     EmitOMPRequiresDecl(cast<OMPRequiresDecl>(D));
5582     break;
5583 
5584   default:
5585     // Make sure we handled everything we should, every other kind is a
5586     // non-top-level decl.  FIXME: Would be nice to have an isTopLevelDeclKind
5587     // function. Need to recode Decl::Kind to do that easily.
5588     assert(isa<TypeDecl>(D) && "Unsupported decl kind");
5589     break;
5590   }
5591 }
5592 
5593 void CodeGenModule::AddDeferredUnusedCoverageMapping(Decl *D) {
5594   // Do we need to generate coverage mapping?
5595   if (!CodeGenOpts.CoverageMapping)
5596     return;
5597   switch (D->getKind()) {
5598   case Decl::CXXConversion:
5599   case Decl::CXXMethod:
5600   case Decl::Function:
5601   case Decl::ObjCMethod:
5602   case Decl::CXXConstructor:
5603   case Decl::CXXDestructor: {
5604     if (!cast<FunctionDecl>(D)->doesThisDeclarationHaveABody())
5605       break;
5606     SourceManager &SM = getContext().getSourceManager();
5607     if (LimitedCoverage && SM.getMainFileID() != SM.getFileID(D->getBeginLoc()))
5608       break;
5609     auto I = DeferredEmptyCoverageMappingDecls.find(D);
5610     if (I == DeferredEmptyCoverageMappingDecls.end())
5611       DeferredEmptyCoverageMappingDecls[D] = true;
5612     break;
5613   }
5614   default:
5615     break;
5616   };
5617 }
5618 
5619 void CodeGenModule::ClearUnusedCoverageMapping(const Decl *D) {
5620   // Do we need to generate coverage mapping?
5621   if (!CodeGenOpts.CoverageMapping)
5622     return;
5623   if (const auto *Fn = dyn_cast<FunctionDecl>(D)) {
5624     if (Fn->isTemplateInstantiation())
5625       ClearUnusedCoverageMapping(Fn->getTemplateInstantiationPattern());
5626   }
5627   auto I = DeferredEmptyCoverageMappingDecls.find(D);
5628   if (I == DeferredEmptyCoverageMappingDecls.end())
5629     DeferredEmptyCoverageMappingDecls[D] = false;
5630   else
5631     I->second = false;
5632 }
5633 
5634 void CodeGenModule::EmitDeferredUnusedCoverageMappings() {
5635   // We call takeVector() here to avoid use-after-free.
5636   // FIXME: DeferredEmptyCoverageMappingDecls is getting mutated because
5637   // we deserialize function bodies to emit coverage info for them, and that
5638   // deserializes more declarations. How should we handle that case?
5639   for (const auto &Entry : DeferredEmptyCoverageMappingDecls.takeVector()) {
5640     if (!Entry.second)
5641       continue;
5642     const Decl *D = Entry.first;
5643     switch (D->getKind()) {
5644     case Decl::CXXConversion:
5645     case Decl::CXXMethod:
5646     case Decl::Function:
5647     case Decl::ObjCMethod: {
5648       CodeGenPGO PGO(*this);
5649       GlobalDecl GD(cast<FunctionDecl>(D));
5650       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
5651                                   getFunctionLinkage(GD));
5652       break;
5653     }
5654     case Decl::CXXConstructor: {
5655       CodeGenPGO PGO(*this);
5656       GlobalDecl GD(cast<CXXConstructorDecl>(D), Ctor_Base);
5657       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
5658                                   getFunctionLinkage(GD));
5659       break;
5660     }
5661     case Decl::CXXDestructor: {
5662       CodeGenPGO PGO(*this);
5663       GlobalDecl GD(cast<CXXDestructorDecl>(D), Dtor_Base);
5664       PGO.emitEmptyCounterMapping(D, getMangledName(GD),
5665                                   getFunctionLinkage(GD));
5666       break;
5667     }
5668     default:
5669       break;
5670     };
5671   }
5672 }
5673 
5674 void CodeGenModule::EmitMainVoidAlias() {
5675   // In order to transition away from "__original_main" gracefully, emit an
5676   // alias for "main" in the no-argument case so that libc can detect when
5677   // new-style no-argument main is in used.
5678   if (llvm::Function *F = getModule().getFunction("main")) {
5679     if (!F->isDeclaration() && F->arg_size() == 0 && !F->isVarArg() &&
5680         F->getReturnType()->isIntegerTy(Context.getTargetInfo().getIntWidth()))
5681       addUsedGlobal(llvm::GlobalAlias::create("__main_void", F));
5682   }
5683 }
5684 
5685 /// Turns the given pointer into a constant.
5686 static llvm::Constant *GetPointerConstant(llvm::LLVMContext &Context,
5687                                           const void *Ptr) {
5688   uintptr_t PtrInt = reinterpret_cast<uintptr_t>(Ptr);
5689   llvm::Type *i64 = llvm::Type::getInt64Ty(Context);
5690   return llvm::ConstantInt::get(i64, PtrInt);
5691 }
5692 
5693 static void EmitGlobalDeclMetadata(CodeGenModule &CGM,
5694                                    llvm::NamedMDNode *&GlobalMetadata,
5695                                    GlobalDecl D,
5696                                    llvm::GlobalValue *Addr) {
5697   if (!GlobalMetadata)
5698     GlobalMetadata =
5699       CGM.getModule().getOrInsertNamedMetadata("clang.global.decl.ptrs");
5700 
5701   // TODO: should we report variant information for ctors/dtors?
5702   llvm::Metadata *Ops[] = {llvm::ConstantAsMetadata::get(Addr),
5703                            llvm::ConstantAsMetadata::get(GetPointerConstant(
5704                                CGM.getLLVMContext(), D.getDecl()))};
5705   GlobalMetadata->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
5706 }
5707 
5708 /// For each function which is declared within an extern "C" region and marked
5709 /// as 'used', but has internal linkage, create an alias from the unmangled
5710 /// name to the mangled name if possible. People expect to be able to refer
5711 /// to such functions with an unmangled name from inline assembly within the
5712 /// same translation unit.
5713 void CodeGenModule::EmitStaticExternCAliases() {
5714   if (!getTargetCodeGenInfo().shouldEmitStaticExternCAliases())
5715     return;
5716   for (auto &I : StaticExternCValues) {
5717     IdentifierInfo *Name = I.first;
5718     llvm::GlobalValue *Val = I.second;
5719     if (Val && !getModule().getNamedValue(Name->getName()))
5720       addUsedGlobal(llvm::GlobalAlias::create(Name->getName(), Val));
5721   }
5722 }
5723 
5724 bool CodeGenModule::lookupRepresentativeDecl(StringRef MangledName,
5725                                              GlobalDecl &Result) const {
5726   auto Res = Manglings.find(MangledName);
5727   if (Res == Manglings.end())
5728     return false;
5729   Result = Res->getValue();
5730   return true;
5731 }
5732 
5733 /// Emits metadata nodes associating all the global values in the
5734 /// current module with the Decls they came from.  This is useful for
5735 /// projects using IR gen as a subroutine.
5736 ///
5737 /// Since there's currently no way to associate an MDNode directly
5738 /// with an llvm::GlobalValue, we create a global named metadata
5739 /// with the name 'clang.global.decl.ptrs'.
5740 void CodeGenModule::EmitDeclMetadata() {
5741   llvm::NamedMDNode *GlobalMetadata = nullptr;
5742 
5743   for (auto &I : MangledDeclNames) {
5744     llvm::GlobalValue *Addr = getModule().getNamedValue(I.second);
5745     // Some mangled names don't necessarily have an associated GlobalValue
5746     // in this module, e.g. if we mangled it for DebugInfo.
5747     if (Addr)
5748       EmitGlobalDeclMetadata(*this, GlobalMetadata, I.first, Addr);
5749   }
5750 }
5751 
5752 /// Emits metadata nodes for all the local variables in the current
5753 /// function.
5754 void CodeGenFunction::EmitDeclMetadata() {
5755   if (LocalDeclMap.empty()) return;
5756 
5757   llvm::LLVMContext &Context = getLLVMContext();
5758 
5759   // Find the unique metadata ID for this name.
5760   unsigned DeclPtrKind = Context.getMDKindID("clang.decl.ptr");
5761 
5762   llvm::NamedMDNode *GlobalMetadata = nullptr;
5763 
5764   for (auto &I : LocalDeclMap) {
5765     const Decl *D = I.first;
5766     llvm::Value *Addr = I.second.getPointer();
5767     if (auto *Alloca = dyn_cast<llvm::AllocaInst>(Addr)) {
5768       llvm::Value *DAddr = GetPointerConstant(getLLVMContext(), D);
5769       Alloca->setMetadata(
5770           DeclPtrKind, llvm::MDNode::get(
5771                            Context, llvm::ValueAsMetadata::getConstant(DAddr)));
5772     } else if (auto *GV = dyn_cast<llvm::GlobalValue>(Addr)) {
5773       GlobalDecl GD = GlobalDecl(cast<VarDecl>(D));
5774       EmitGlobalDeclMetadata(CGM, GlobalMetadata, GD, GV);
5775     }
5776   }
5777 }
5778 
5779 void CodeGenModule::EmitVersionIdentMetadata() {
5780   llvm::NamedMDNode *IdentMetadata =
5781     TheModule.getOrInsertNamedMetadata("llvm.ident");
5782   std::string Version = getClangFullVersion();
5783   llvm::LLVMContext &Ctx = TheModule.getContext();
5784 
5785   llvm::Metadata *IdentNode[] = {llvm::MDString::get(Ctx, Version)};
5786   IdentMetadata->addOperand(llvm::MDNode::get(Ctx, IdentNode));
5787 }
5788 
5789 void CodeGenModule::EmitCommandLineMetadata() {
5790   llvm::NamedMDNode *CommandLineMetadata =
5791     TheModule.getOrInsertNamedMetadata("llvm.commandline");
5792   std::string CommandLine = getCodeGenOpts().RecordCommandLine;
5793   llvm::LLVMContext &Ctx = TheModule.getContext();
5794 
5795   llvm::Metadata *CommandLineNode[] = {llvm::MDString::get(Ctx, CommandLine)};
5796   CommandLineMetadata->addOperand(llvm::MDNode::get(Ctx, CommandLineNode));
5797 }
5798 
5799 void CodeGenModule::EmitCoverageFile() {
5800   if (getCodeGenOpts().CoverageDataFile.empty() &&
5801       getCodeGenOpts().CoverageNotesFile.empty())
5802     return;
5803 
5804   llvm::NamedMDNode *CUNode = TheModule.getNamedMetadata("llvm.dbg.cu");
5805   if (!CUNode)
5806     return;
5807 
5808   llvm::NamedMDNode *GCov = TheModule.getOrInsertNamedMetadata("llvm.gcov");
5809   llvm::LLVMContext &Ctx = TheModule.getContext();
5810   auto *CoverageDataFile =
5811       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageDataFile);
5812   auto *CoverageNotesFile =
5813       llvm::MDString::get(Ctx, getCodeGenOpts().CoverageNotesFile);
5814   for (int i = 0, e = CUNode->getNumOperands(); i != e; ++i) {
5815     llvm::MDNode *CU = CUNode->getOperand(i);
5816     llvm::Metadata *Elts[] = {CoverageNotesFile, CoverageDataFile, CU};
5817     GCov->addOperand(llvm::MDNode::get(Ctx, Elts));
5818   }
5819 }
5820 
5821 llvm::Constant *CodeGenModule::GetAddrOfRTTIDescriptor(QualType Ty,
5822                                                        bool ForEH) {
5823   // Return a bogus pointer if RTTI is disabled, unless it's for EH.
5824   // FIXME: should we even be calling this method if RTTI is disabled
5825   // and it's not for EH?
5826   if ((!ForEH && !getLangOpts().RTTI) || getLangOpts().CUDAIsDevice ||
5827       (getLangOpts().OpenMP && getLangOpts().OpenMPIsDevice &&
5828        getTriple().isNVPTX()))
5829     return llvm::Constant::getNullValue(Int8PtrTy);
5830 
5831   if (ForEH && Ty->isObjCObjectPointerType() &&
5832       LangOpts.ObjCRuntime.isGNUFamily())
5833     return ObjCRuntime->GetEHType(Ty);
5834 
5835   return getCXXABI().getAddrOfRTTIDescriptor(Ty);
5836 }
5837 
5838 void CodeGenModule::EmitOMPThreadPrivateDecl(const OMPThreadPrivateDecl *D) {
5839   // Do not emit threadprivates in simd-only mode.
5840   if (LangOpts.OpenMP && LangOpts.OpenMPSimd)
5841     return;
5842   for (auto RefExpr : D->varlists()) {
5843     auto *VD = cast<VarDecl>(cast<DeclRefExpr>(RefExpr)->getDecl());
5844     bool PerformInit =
5845         VD->getAnyInitializer() &&
5846         !VD->getAnyInitializer()->isConstantInitializer(getContext(),
5847                                                         /*ForRef=*/false);
5848 
5849     Address Addr(GetAddrOfGlobalVar(VD), getContext().getDeclAlign(VD));
5850     if (auto InitFunction = getOpenMPRuntime().emitThreadPrivateVarDefinition(
5851             VD, Addr, RefExpr->getBeginLoc(), PerformInit))
5852       CXXGlobalInits.push_back(InitFunction);
5853   }
5854 }
5855 
5856 llvm::Metadata *
5857 CodeGenModule::CreateMetadataIdentifierImpl(QualType T, MetadataTypeMap &Map,
5858                                             StringRef Suffix) {
5859   llvm::Metadata *&InternalId = Map[T.getCanonicalType()];
5860   if (InternalId)
5861     return InternalId;
5862 
5863   if (isExternallyVisible(T->getLinkage())) {
5864     std::string OutName;
5865     llvm::raw_string_ostream Out(OutName);
5866     getCXXABI().getMangleContext().mangleTypeName(T, Out);
5867     Out << Suffix;
5868 
5869     InternalId = llvm::MDString::get(getLLVMContext(), Out.str());
5870   } else {
5871     InternalId = llvm::MDNode::getDistinct(getLLVMContext(),
5872                                            llvm::ArrayRef<llvm::Metadata *>());
5873   }
5874 
5875   return InternalId;
5876 }
5877 
5878 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierForType(QualType T) {
5879   return CreateMetadataIdentifierImpl(T, MetadataIdMap, "");
5880 }
5881 
5882 llvm::Metadata *
5883 CodeGenModule::CreateMetadataIdentifierForVirtualMemPtrType(QualType T) {
5884   return CreateMetadataIdentifierImpl(T, VirtualMetadataIdMap, ".virtual");
5885 }
5886 
5887 // Generalize pointer types to a void pointer with the qualifiers of the
5888 // originally pointed-to type, e.g. 'const char *' and 'char * const *'
5889 // generalize to 'const void *' while 'char *' and 'const char **' generalize to
5890 // 'void *'.
5891 static QualType GeneralizeType(ASTContext &Ctx, QualType Ty) {
5892   if (!Ty->isPointerType())
5893     return Ty;
5894 
5895   return Ctx.getPointerType(
5896       QualType(Ctx.VoidTy).withCVRQualifiers(
5897           Ty->getPointeeType().getCVRQualifiers()));
5898 }
5899 
5900 // Apply type generalization to a FunctionType's return and argument types
5901 static QualType GeneralizeFunctionType(ASTContext &Ctx, QualType Ty) {
5902   if (auto *FnType = Ty->getAs<FunctionProtoType>()) {
5903     SmallVector<QualType, 8> GeneralizedParams;
5904     for (auto &Param : FnType->param_types())
5905       GeneralizedParams.push_back(GeneralizeType(Ctx, Param));
5906 
5907     return Ctx.getFunctionType(
5908         GeneralizeType(Ctx, FnType->getReturnType()),
5909         GeneralizedParams, FnType->getExtProtoInfo());
5910   }
5911 
5912   if (auto *FnType = Ty->getAs<FunctionNoProtoType>())
5913     return Ctx.getFunctionNoProtoType(
5914         GeneralizeType(Ctx, FnType->getReturnType()));
5915 
5916   llvm_unreachable("Encountered unknown FunctionType");
5917 }
5918 
5919 llvm::Metadata *CodeGenModule::CreateMetadataIdentifierGeneralized(QualType T) {
5920   return CreateMetadataIdentifierImpl(GeneralizeFunctionType(getContext(), T),
5921                                       GeneralizedMetadataIdMap, ".generalized");
5922 }
5923 
5924 /// Returns whether this module needs the "all-vtables" type identifier.
5925 bool CodeGenModule::NeedAllVtablesTypeId() const {
5926   // Returns true if at least one of vtable-based CFI checkers is enabled and
5927   // is not in the trapping mode.
5928   return ((LangOpts.Sanitize.has(SanitizerKind::CFIVCall) &&
5929            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIVCall)) ||
5930           (LangOpts.Sanitize.has(SanitizerKind::CFINVCall) &&
5931            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFINVCall)) ||
5932           (LangOpts.Sanitize.has(SanitizerKind::CFIDerivedCast) &&
5933            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIDerivedCast)) ||
5934           (LangOpts.Sanitize.has(SanitizerKind::CFIUnrelatedCast) &&
5935            !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIUnrelatedCast)));
5936 }
5937 
5938 void CodeGenModule::AddVTableTypeMetadata(llvm::GlobalVariable *VTable,
5939                                           CharUnits Offset,
5940                                           const CXXRecordDecl *RD) {
5941   llvm::Metadata *MD =
5942       CreateMetadataIdentifierForType(QualType(RD->getTypeForDecl(), 0));
5943   VTable->addTypeMetadata(Offset.getQuantity(), MD);
5944 
5945   if (CodeGenOpts.SanitizeCfiCrossDso)
5946     if (auto CrossDsoTypeId = CreateCrossDsoCfiTypeId(MD))
5947       VTable->addTypeMetadata(Offset.getQuantity(),
5948                               llvm::ConstantAsMetadata::get(CrossDsoTypeId));
5949 
5950   if (NeedAllVtablesTypeId()) {
5951     llvm::Metadata *MD = llvm::MDString::get(getLLVMContext(), "all-vtables");
5952     VTable->addTypeMetadata(Offset.getQuantity(), MD);
5953   }
5954 }
5955 
5956 llvm::SanitizerStatReport &CodeGenModule::getSanStats() {
5957   if (!SanStats)
5958     SanStats = std::make_unique<llvm::SanitizerStatReport>(&getModule());
5959 
5960   return *SanStats;
5961 }
5962 llvm::Value *
5963 CodeGenModule::createOpenCLIntToSamplerConversion(const Expr *E,
5964                                                   CodeGenFunction &CGF) {
5965   llvm::Constant *C = ConstantEmitter(CGF).emitAbstract(E, E->getType());
5966   auto SamplerT = getOpenCLRuntime().getSamplerType(E->getType().getTypePtr());
5967   auto FTy = llvm::FunctionType::get(SamplerT, {C->getType()}, false);
5968   return CGF.Builder.CreateCall(CreateRuntimeFunction(FTy,
5969                                 "__translate_sampler_initializer"),
5970                                 {C});
5971 }
5972 
5973 CharUnits CodeGenModule::getNaturalPointeeTypeAlignment(
5974     QualType T, LValueBaseInfo *BaseInfo, TBAAAccessInfo *TBAAInfo) {
5975   return getNaturalTypeAlignment(T->getPointeeType(), BaseInfo, TBAAInfo,
5976                                  /* forPointeeType= */ true);
5977 }
5978 
5979 CharUnits CodeGenModule::getNaturalTypeAlignment(QualType T,
5980                                                  LValueBaseInfo *BaseInfo,
5981                                                  TBAAAccessInfo *TBAAInfo,
5982                                                  bool forPointeeType) {
5983   if (TBAAInfo)
5984     *TBAAInfo = getTBAAAccessInfo(T);
5985 
5986   // FIXME: This duplicates logic in ASTContext::getTypeAlignIfKnown. But
5987   // that doesn't return the information we need to compute BaseInfo.
5988 
5989   // Honor alignment typedef attributes even on incomplete types.
5990   // We also honor them straight for C++ class types, even as pointees;
5991   // there's an expressivity gap here.
5992   if (auto TT = T->getAs<TypedefType>()) {
5993     if (auto Align = TT->getDecl()->getMaxAlignment()) {
5994       if (BaseInfo)
5995         *BaseInfo = LValueBaseInfo(AlignmentSource::AttributedType);
5996       return getContext().toCharUnitsFromBits(Align);
5997     }
5998   }
5999 
6000   bool AlignForArray = T->isArrayType();
6001 
6002   // Analyze the base element type, so we don't get confused by incomplete
6003   // array types.
6004   T = getContext().getBaseElementType(T);
6005 
6006   if (T->isIncompleteType()) {
6007     // We could try to replicate the logic from
6008     // ASTContext::getTypeAlignIfKnown, but nothing uses the alignment if the
6009     // type is incomplete, so it's impossible to test. We could try to reuse
6010     // getTypeAlignIfKnown, but that doesn't return the information we need
6011     // to set BaseInfo.  So just ignore the possibility that the alignment is
6012     // greater than one.
6013     if (BaseInfo)
6014       *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
6015     return CharUnits::One();
6016   }
6017 
6018   if (BaseInfo)
6019     *BaseInfo = LValueBaseInfo(AlignmentSource::Type);
6020 
6021   CharUnits Alignment;
6022   // For C++ class pointees, we don't know whether we're pointing at a
6023   // base or a complete object, so we generally need to use the
6024   // non-virtual alignment.
6025   const CXXRecordDecl *RD;
6026   if (forPointeeType && !AlignForArray && (RD = T->getAsCXXRecordDecl())) {
6027     Alignment = getClassPointerAlignment(RD);
6028   } else {
6029     Alignment = getContext().getTypeAlignInChars(T);
6030     if (T.getQualifiers().hasUnaligned())
6031       Alignment = CharUnits::One();
6032   }
6033 
6034   // Cap to the global maximum type alignment unless the alignment
6035   // was somehow explicit on the type.
6036   if (unsigned MaxAlign = getLangOpts().MaxTypeAlign) {
6037     if (Alignment.getQuantity() > MaxAlign &&
6038         !getContext().isAlignmentRequired(T))
6039       Alignment = CharUnits::fromQuantity(MaxAlign);
6040   }
6041   return Alignment;
6042 }
6043 
6044 bool CodeGenModule::stopAutoInit() {
6045   unsigned StopAfter = getContext().getLangOpts().TrivialAutoVarInitStopAfter;
6046   if (StopAfter) {
6047     // This number is positive only when -ftrivial-auto-var-init-stop-after=* is
6048     // used
6049     if (NumAutoVarInit >= StopAfter) {
6050       return true;
6051     }
6052     if (!NumAutoVarInit) {
6053       unsigned DiagID = getDiags().getCustomDiagID(
6054           DiagnosticsEngine::Warning,
6055           "-ftrivial-auto-var-init-stop-after=%0 has been enabled to limit the "
6056           "number of times ftrivial-auto-var-init=%1 gets applied.");
6057       getDiags().Report(DiagID)
6058           << StopAfter
6059           << (getContext().getLangOpts().getTrivialAutoVarInit() ==
6060                       LangOptions::TrivialAutoVarInitKind::Zero
6061                   ? "zero"
6062                   : "pattern");
6063     }
6064     ++NumAutoVarInit;
6065   }
6066   return false;
6067 }
6068