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