clang/lib/CodeGen/CodeGenAction.cpp

   1 //===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
   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 #include "clang/CodeGen/CodeGenAction.h"
  10 #include "BackendConsumer.h"
  11 #include "CGCall.h"
  12 #include "CodeGenModule.h"
  13 #include "CoverageMappingGen.h"
  14 #include "MacroPPCallbacks.h"
  15 #include "clang/AST/ASTConsumer.h"
  16 #include "clang/AST/ASTContext.h"
  17 #include "clang/AST/DeclCXX.h"
  18 #include "clang/AST/DeclGroup.h"
  19 #include "clang/Basic/DiagnosticFrontend.h"
  20 #include "clang/Basic/FileManager.h"
  21 #include "clang/Basic/LangStandard.h"
  22 #include "clang/Basic/SourceManager.h"
  23 #include "clang/Basic/TargetInfo.h"
  24 #include "clang/CodeGen/BackendUtil.h"
  25 #include "clang/CodeGen/ModuleBuilder.h"
  26 #include "clang/Driver/DriverDiagnostic.h"
  27 #include "clang/Frontend/CompilerInstance.h"
  28 #include "clang/Frontend/MultiplexConsumer.h"
  29 #include "clang/Lex/Preprocessor.h"
  30 #include "clang/Serialization/ASTWriter.h"
  31 #include "llvm/ADT/Hashing.h"
  32 #include "llvm/Bitcode/BitcodeReader.h"
  33 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
  34 #include "llvm/Demangle/Demangle.h"
  35 #include "llvm/IR/DebugInfo.h"
  36 #include "llvm/IR/DiagnosticInfo.h"
  37 #include "llvm/IR/DiagnosticPrinter.h"
  38 #include "llvm/IR/GlobalValue.h"
  39 #include "llvm/IR/LLVMContext.h"
  40 #include "llvm/IR/LLVMRemarkStreamer.h"
  41 #include "llvm/IR/Module.h"
  42 #include "llvm/IRReader/IRReader.h"
  43 #include "llvm/LTO/LTOBackend.h"
  44 #include "llvm/Linker/Linker.h"
  45 #include "llvm/Pass.h"
  46 #include "llvm/Support/MemoryBuffer.h"
  47 #include "llvm/Support/SourceMgr.h"
  48 #include "llvm/Support/TimeProfiler.h"
  49 #include "llvm/Support/Timer.h"
  50 #include "llvm/Support/ToolOutputFile.h"
  51 #include "llvm/Transforms/IPO/Internalize.h"
  52 #include "llvm/Transforms/Utils/Cloning.h"
  53
  54 #include <optional>
  55 using namespace clang;
  56 using namespace llvm;
  57
  58 #define DEBUG_TYPE "codegenaction"
  59
  60 namespace clang {
  61 class BackendConsumer;
  62 class ClangDiagnosticHandler final : public DiagnosticHandler {
  63 public:
  64   ClangDiagnosticHandler(const CodeGenOptions &CGOpts, BackendConsumer *BCon)
  65       : CodeGenOpts(CGOpts), BackendCon(BCon) {}
  66
  67   bool handleDiagnostics(const DiagnosticInfo &DI) override;
  68
  69   bool isAnalysisRemarkEnabled(StringRef PassName) const override {
  70     return CodeGenOpts.OptimizationRemarkAnalysis.patternMatches(PassName);
  71   }
  72   bool isMissedOptRemarkEnabled(StringRef PassName) const override {
  73     return CodeGenOpts.OptimizationRemarkMissed.patternMatches(PassName);
  74   }
  75   bool isPassedOptRemarkEnabled(StringRef PassName) const override {
  76     return CodeGenOpts.OptimizationRemark.patternMatches(PassName);
  77   }
  78
  79   bool isAnyRemarkEnabled() const override {
  80     return CodeGenOpts.OptimizationRemarkAnalysis.hasValidPattern() ||
  81            CodeGenOpts.OptimizationRemarkMissed.hasValidPattern() ||
  82            CodeGenOpts.OptimizationRemark.hasValidPattern();
  83   }
  84
  85 private:
  86   const CodeGenOptions &CodeGenOpts;
  87   BackendConsumer *BackendCon;
  88 };
  89
  90 static void reportOptRecordError(Error E, DiagnosticsEngine &Diags,
  91                                  const CodeGenOptions &CodeGenOpts) {
  92   handleAllErrors(
  93       std::move(E),
  94     [&](const LLVMRemarkSetupFileError &E) {
  95         Diags.Report(diag::err_cannot_open_file)
  96             << CodeGenOpts.OptRecordFile << E.message();
  97       },
  98     [&](const LLVMRemarkSetupPatternError &E) {
  99         Diags.Report(diag::err_drv_optimization_remark_pattern)
 100             << E.message() << CodeGenOpts.OptRecordPasses;
 101       },
 102     [&](const LLVMRemarkSetupFormatError &E) {
 103         Diags.Report(diag::err_drv_optimization_remark_format)
 104             << CodeGenOpts.OptRecordFormat;
 105       });
 106 }
 107
 108 BackendConsumer::BackendConsumer(
 109     BackendAction Action, DiagnosticsEngine &Diags,
 110     IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
 111     const HeaderSearchOptions &HeaderSearchOpts,
 112     const PreprocessorOptions &PPOpts, const CodeGenOptions &CodeGenOpts,
 113     const TargetOptions &TargetOpts, const LangOptions &LangOpts,
 114     const std::string &InFile, SmallVector<LinkModule, 4> LinkModules,
 115     std::unique_ptr<raw_pwrite_stream> OS, LLVMContext &C,
 116     CoverageSourceInfo *CoverageInfo)
 117     : Diags(Diags), Action(Action), HeaderSearchOpts(HeaderSearchOpts),
 118       CodeGenOpts(CodeGenOpts), TargetOpts(TargetOpts), LangOpts(LangOpts),
 119       AsmOutStream(std::move(OS)), Context(nullptr), FS(VFS),
 120       LLVMIRGeneration("irgen", "LLVM IR Generation Time"),
 121       LLVMIRGenerationRefCount(0),
 122       Gen(CreateLLVMCodeGen(Diags, InFile, std::move(VFS), HeaderSearchOpts,
 123                             PPOpts, CodeGenOpts, C, CoverageInfo)),
 124       LinkModules(std::move(LinkModules)) {
 125   TimerIsEnabled = CodeGenOpts.TimePasses;
 126   llvm::TimePassesIsEnabled = CodeGenOpts.TimePasses;
 127   llvm::TimePassesPerRun = CodeGenOpts.TimePassesPerRun;
 128 }
 129
 130 // This constructor is used in installing an empty BackendConsumer
 131 // to use the clang diagnostic handler for IR input files. It avoids
 132 // initializing the OS field.
 133 BackendConsumer::BackendConsumer(
 134     BackendAction Action, DiagnosticsEngine &Diags,
 135     IntrusiveRefCntPtr<llvm::vfs::FileSystem> VFS,
 136     const HeaderSearchOptions &HeaderSearchOpts,
 137     const PreprocessorOptions &PPOpts, const CodeGenOptions &CodeGenOpts,
 138     const TargetOptions &TargetOpts, const LangOptions &LangOpts,
 139     llvm::Module *Module, SmallVector<LinkModule, 4> LinkModules,
 140     LLVMContext &C, CoverageSourceInfo *CoverageInfo)
 141     : Diags(Diags), Action(Action), HeaderSearchOpts(HeaderSearchOpts),
 142       CodeGenOpts(CodeGenOpts), TargetOpts(TargetOpts), LangOpts(LangOpts),
 143       Context(nullptr), FS(VFS),
 144       LLVMIRGeneration("irgen", "LLVM IR Generation Time"),
 145       LLVMIRGenerationRefCount(0),
 146       Gen(CreateLLVMCodeGen(Diags, "", std::move(VFS), HeaderSearchOpts, PPOpts,
 147                             CodeGenOpts, C, CoverageInfo)),
 148       LinkModules(std::move(LinkModules)), CurLinkModule(Module) {
 149   TimerIsEnabled = CodeGenOpts.TimePasses;
 150   llvm::TimePassesIsEnabled = CodeGenOpts.TimePasses;
 151   llvm::TimePassesPerRun = CodeGenOpts.TimePassesPerRun;
 152 }
 153
 154 llvm::Module* BackendConsumer::getModule() const {
 155   return Gen->GetModule();
 156 }
 157
 158 std::unique_ptr<llvm::Module> BackendConsumer::takeModule() {
 159   return std::unique_ptr<llvm::Module>(Gen->ReleaseModule());
 160 }
 161
 162 CodeGenerator* BackendConsumer::getCodeGenerator() {
 163   return Gen.get();
 164 }
 165
 166 void BackendConsumer::HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
 167   Gen->HandleCXXStaticMemberVarInstantiation(VD);
 168 }
 169
 170 void BackendConsumer::Initialize(ASTContext &Ctx) {
 171   assert(!Context && "initialized multiple times");
 172
 173   Context = &Ctx;
 174
 175   if (TimerIsEnabled)
 176     LLVMIRGeneration.startTimer();
 177
 178   Gen->Initialize(Ctx);
 179
 180   if (TimerIsEnabled)
 181     LLVMIRGeneration.stopTimer();
 182 }
 183
 184 bool BackendConsumer::HandleTopLevelDecl(DeclGroupRef D) {
 185   PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
 186                                  Context->getSourceManager(),
 187                                  "LLVM IR generation of declaration");
 188
 189   // Recurse.
 190   if (TimerIsEnabled) {
 191     LLVMIRGenerationRefCount += 1;
 192     if (LLVMIRGenerationRefCount == 1)
 193       LLVMIRGeneration.startTimer();
 194   }
 195
 196   Gen->HandleTopLevelDecl(D);
 197
 198   if (TimerIsEnabled) {
 199     LLVMIRGenerationRefCount -= 1;
 200     if (LLVMIRGenerationRefCount == 0)
 201       LLVMIRGeneration.stopTimer();
 202   }
 203
 204   return true;
 205 }
 206
 207 void BackendConsumer::HandleInlineFunctionDefinition(FunctionDecl *D) {
 208   PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
 209                                  Context->getSourceManager(),
 210                                  "LLVM IR generation of inline function");
 211   if (TimerIsEnabled)
 212     LLVMIRGeneration.startTimer();
 213
 214   Gen->HandleInlineFunctionDefinition(D);
 215
 216   if (TimerIsEnabled)
 217     LLVMIRGeneration.stopTimer();
 218 }
 219
 220 void BackendConsumer::HandleInterestingDecl(DeclGroupRef D) {
 221   // Ignore interesting decls from the AST reader after IRGen is finished.
 222   if (!IRGenFinished)
 223     HandleTopLevelDecl(D);
 224 }
 225
 226 // Links each entry in LinkModules into our module. Returns true on error.
 227 bool BackendConsumer::LinkInModules(llvm::Module *M) {
 228   for (auto &LM : LinkModules) {
 229     assert(LM.Module && "LinkModule does not actually have a module");
 230
 231     if (LM.PropagateAttrs)
 232       for (Function &F : *LM.Module) {
 233         // Skip intrinsics. Keep consistent with how intrinsics are created
 234         // in LLVM IR.
 235         if (F.isIntrinsic())
 236           continue;
 237         CodeGen::mergeDefaultFunctionDefinitionAttributes(
 238           F, CodeGenOpts, LangOpts, TargetOpts, LM.Internalize);
 239       }
 240
 241     CurLinkModule = LM.Module.get();
 242     bool Err;
 243
 244     if (LM.Internalize) {
 245       Err = Linker::linkModules(
 246           *M, std::move(LM.Module), LM.LinkFlags,
 247           [](llvm::Module &M, const llvm::StringSet<> &GVS) {
 248             internalizeModule(M, [&GVS](const llvm::GlobalValue &GV) {
 249               return !GV.hasName() || (GVS.count(GV.getName()) == 0);
 250             });
 251           });
 252     } else
 253       Err = Linker::linkModules(*M, std::move(LM.Module), LM.LinkFlags);
 254
 255     if (Err)
 256       return true;
 257   }
 258
 259   LinkModules.clear();
 260   return false; // success
 261 }
 262
 263 void BackendConsumer::HandleTranslationUnit(ASTContext &C) {
 264   {
 265     llvm::TimeTraceScope TimeScope("Frontend");
 266     PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
 267     if (TimerIsEnabled) {
 268       LLVMIRGenerationRefCount += 1;
 269       if (LLVMIRGenerationRefCount == 1)
 270         LLVMIRGeneration.startTimer();
 271     }
 272
 273     Gen->HandleTranslationUnit(C);
 274
 275     if (TimerIsEnabled) {
 276       LLVMIRGenerationRefCount -= 1;
 277       if (LLVMIRGenerationRefCount == 0)
 278         LLVMIRGeneration.stopTimer();
 279     }
 280
 281     IRGenFinished = true;
 282   }
 283
 284   // Silently ignore if we weren't initialized for some reason.
 285   if (!getModule())
 286     return;
 287
 288   LLVMContext &Ctx = getModule()->getContext();
 289   std::unique_ptr<DiagnosticHandler> OldDiagnosticHandler =
 290     Ctx.getDiagnosticHandler();
 291   Ctx.setDiagnosticHandler(std::make_unique<ClangDiagnosticHandler>(
 292       CodeGenOpts, this));
 293
 294   Ctx.setDefaultTargetCPU(TargetOpts.CPU);
 295   Ctx.setDefaultTargetFeatures(llvm::join(TargetOpts.Features, ","));
 296
 297   Expected<std::unique_ptr<llvm::ToolOutputFile>> OptRecordFileOrErr =
 298     setupLLVMOptimizationRemarks(
 299       Ctx, CodeGenOpts.OptRecordFile, CodeGenOpts.OptRecordPasses,
 300       CodeGenOpts.OptRecordFormat, CodeGenOpts.DiagnosticsWithHotness,
 301       CodeGenOpts.DiagnosticsHotnessThreshold);
 302
 303   if (Error E = OptRecordFileOrErr.takeError()) {
 304     reportOptRecordError(std::move(E), Diags, CodeGenOpts);
 305     return;
 306   }
 307
 308   std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
 309     std::move(*OptRecordFileOrErr);
 310
 311   if (OptRecordFile &&
 312       CodeGenOpts.getProfileUse() != CodeGenOptions::ProfileNone)
 313     Ctx.setDiagnosticsHotnessRequested(true);
 314
 315   if (CodeGenOpts.MisExpect) {
 316     Ctx.setMisExpectWarningRequested(true);
 317   }
 318
 319   if (CodeGenOpts.DiagnosticsMisExpectTolerance) {
 320     Ctx.setDiagnosticsMisExpectTolerance(
 321       CodeGenOpts.DiagnosticsMisExpectTolerance);
 322   }
 323
 324   // Link each LinkModule into our module.
 325   if (!CodeGenOpts.LinkBitcodePostopt && LinkInModules(getModule()))
 326     return;
 327
 328   for (auto &F : getModule()->functions()) {
 329     if (const Decl *FD = Gen->GetDeclForMangledName(F.getName())) {
 330       auto Loc = FD->getASTContext().getFullLoc(FD->getLocation());
 331       // TODO: use a fast content hash when available.
 332       auto NameHash = llvm::hash_value(F.getName());
 333       ManglingFullSourceLocs.push_back(std::make_pair(NameHash, Loc));
 334     }
 335   }
 336
 337   if (CodeGenOpts.ClearASTBeforeBackend) {
 338     LLVM_DEBUG(llvm::dbgs() << "Clearing AST...\n");
 339     // Access to the AST is no longer available after this.
 340     // Other things that the ASTContext manages are still available, e.g.
 341     // the SourceManager. It'd be nice if we could separate out all the
 342     // things in ASTContext used after this point and null out the
 343     // ASTContext, but too many various parts of the ASTContext are still
 344     // used in various parts.
 345     C.cleanup();
 346     C.getAllocator().Reset();
 347   }
 348
 349   EmbedBitcode(getModule(), CodeGenOpts, llvm::MemoryBufferRef());
 350
 351   EmitBackendOutput(Diags, HeaderSearchOpts, CodeGenOpts, TargetOpts, LangOpts,
 352                     C.getTargetInfo().getDataLayoutString(), getModule(),
 353                     Action, FS, std::move(AsmOutStream), this);
 354
 355   Ctx.setDiagnosticHandler(std::move(OldDiagnosticHandler));
 356
 357   if (OptRecordFile)
 358     OptRecordFile->keep();
 359 }
 360
 361 void BackendConsumer::HandleTagDeclDefinition(TagDecl *D) {
 362   PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
 363                                  Context->getSourceManager(),
 364                                  "LLVM IR generation of declaration");
 365   Gen->HandleTagDeclDefinition(D);
 366 }
 367
 368 void BackendConsumer::HandleTagDeclRequiredDefinition(const TagDecl *D) {
 369   Gen->HandleTagDeclRequiredDefinition(D);
 370 }
 371
 372 void BackendConsumer::CompleteTentativeDefinition(VarDecl *D) {
 373   Gen->CompleteTentativeDefinition(D);
 374 }
 375
 376 void BackendConsumer::CompleteExternalDeclaration(DeclaratorDecl *D) {
 377   Gen->CompleteExternalDeclaration(D);
 378 }
 379
 380 void BackendConsumer::AssignInheritanceModel(CXXRecordDecl *RD) {
 381   Gen->AssignInheritanceModel(RD);
 382 }
 383
 384 void BackendConsumer::HandleVTable(CXXRecordDecl *RD) {
 385   Gen->HandleVTable(RD);
 386 }
 387
 388 void BackendConsumer::anchor() { }
 389
 390 } // namespace clang
 391
 392 bool ClangDiagnosticHandler::handleDiagnostics(const DiagnosticInfo &DI) {
 393   BackendCon->DiagnosticHandlerImpl(DI);
 394   return true;
 395 }
 396
 397 /// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
 398 /// buffer to be a valid FullSourceLoc.
 399 static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
 400                                             SourceManager &CSM) {
 401   // Get both the clang and llvm source managers.  The location is relative to
 402   // a memory buffer that the LLVM Source Manager is handling, we need to add
 403   // a copy to the Clang source manager.
 404   const llvm::SourceMgr &LSM = *D.getSourceMgr();
 405
 406   // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
 407   // already owns its one and clang::SourceManager wants to own its one.
 408   const MemoryBuffer *LBuf =
 409   LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
 410
 411   // Create the copy and transfer ownership to clang::SourceManager.
 412   // TODO: Avoid copying files into memory.
 413   std::unique_ptr<llvm::MemoryBuffer> CBuf =
 414       llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
 415                                            LBuf->getBufferIdentifier());
 416   // FIXME: Keep a file ID map instead of creating new IDs for each location.
 417   FileID FID = CSM.createFileID(std::move(CBuf));
 418
 419   // Translate the offset into the file.
 420   unsigned Offset = D.getLoc().getPointer() - LBuf->getBufferStart();
 421   SourceLocation NewLoc =
 422   CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
 423   return FullSourceLoc(NewLoc, CSM);
 424 }
 425
 426 #define ComputeDiagID(Severity, GroupName, DiagID)                             \
 427   do {                                                                         \
 428     switch (Severity) {                                                        \
 429     case llvm::DS_Error:                                                       \
 430       DiagID = diag::err_fe_##GroupName;                                       \
 431       break;                                                                   \
 432     case llvm::DS_Warning:                                                     \
 433       DiagID = diag::warn_fe_##GroupName;                                      \
 434       break;                                                                   \
 435     case llvm::DS_Remark:                                                      \
 436       llvm_unreachable("'remark' severity not expected");                      \
 437       break;                                                                   \
 438     case llvm::DS_Note:                                                        \
 439       DiagID = diag::note_fe_##GroupName;                                      \
 440       break;                                                                   \
 441     }                                                                          \
 442   } while (false)
 443
 444 #define ComputeDiagRemarkID(Severity, GroupName, DiagID)                       \
 445   do {                                                                         \
 446     switch (Severity) {                                                        \
 447     case llvm::DS_Error:                                                       \
 448       DiagID = diag::err_fe_##GroupName;                                       \
 449       break;                                                                   \
 450     case llvm::DS_Warning:                                                     \
 451       DiagID = diag::warn_fe_##GroupName;                                      \
 452       break;                                                                   \
 453     case llvm::DS_Remark:                                                      \
 454       DiagID = diag::remark_fe_##GroupName;                                    \
 455       break;                                                                   \
 456     case llvm::DS_Note:                                                        \
 457       DiagID = diag::note_fe_##GroupName;                                      \
 458       break;                                                                   \
 459     }                                                                          \
 460   } while (false)
 461
 462 void BackendConsumer::SrcMgrDiagHandler(const llvm::DiagnosticInfoSrcMgr &DI) {
 463   const llvm::SMDiagnostic &D = DI.getSMDiag();
 464
 465   unsigned DiagID;
 466   if (DI.isInlineAsmDiag())
 467     ComputeDiagID(DI.getSeverity(), inline_asm, DiagID);
 468   else
 469     ComputeDiagID(DI.getSeverity(), source_mgr, DiagID);
 470
 471   // This is for the empty BackendConsumer that uses the clang diagnostic
 472   // handler for IR input files.
 473   if (!Context) {
 474     D.print(nullptr, llvm::errs());
 475     Diags.Report(DiagID).AddString("cannot compile inline asm");
 476     return;
 477   }
 478
 479   // There are a couple of different kinds of errors we could get here.
 480   // First, we re-format the SMDiagnostic in terms of a clang diagnostic.
 481
 482   // Strip "error: " off the start of the message string.
 483   StringRef Message = D.getMessage();
 484   (void)Message.consume_front("error: ");
 485
 486   // If the SMDiagnostic has an inline asm source location, translate it.
 487   FullSourceLoc Loc;
 488   if (D.getLoc() != SMLoc())
 489     Loc = ConvertBackendLocation(D, Context->getSourceManager());
 490
 491   // If this problem has clang-level source location information, report the
 492   // issue in the source with a note showing the instantiated
 493   // code.
 494   if (DI.isInlineAsmDiag()) {
 495     SourceLocation LocCookie =
 496         SourceLocation::getFromRawEncoding(DI.getLocCookie());
 497     if (LocCookie.isValid()) {
 498       Diags.Report(LocCookie, DiagID).AddString(Message);
 499
 500       if (D.getLoc().isValid()) {
 501         DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
 502         // Convert the SMDiagnostic ranges into SourceRange and attach them
 503         // to the diagnostic.
 504         for (const std::pair<unsigned, unsigned> &Range : D.getRanges()) {
 505           unsigned Column = D.getColumnNo();
 506           B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
 507                            Loc.getLocWithOffset(Range.second - Column));
 508         }
 509       }
 510       return;
 511     }
 512   }
 513
 514   // Otherwise, report the backend issue as occurring in the generated .s file.
 515   // If Loc is invalid, we still need to report the issue, it just gets no
 516   // location info.
 517   Diags.Report(Loc, DiagID).AddString(Message);
 518 }
 519
 520 bool
 521 BackendConsumer::InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D) {
 522   unsigned DiagID;
 523   ComputeDiagID(D.getSeverity(), inline_asm, DiagID);
 524   std::string Message = D.getMsgStr().str();
 525
 526   // If this problem has clang-level source location information, report the
 527   // issue as being a problem in the source with a note showing the instantiated
 528   // code.
 529   SourceLocation LocCookie =
 530       SourceLocation::getFromRawEncoding(D.getLocCookie());
 531   if (LocCookie.isValid())
 532     Diags.Report(LocCookie, DiagID).AddString(Message);
 533   else {
 534     // Otherwise, report the backend diagnostic as occurring in the generated
 535     // .s file.
 536     // If Loc is invalid, we still need to report the diagnostic, it just gets
 537     // no location info.
 538     FullSourceLoc Loc;
 539     Diags.Report(Loc, DiagID).AddString(Message);
 540   }
 541   // We handled all the possible severities.
 542   return true;
 543 }
 544
 545 bool
 546 BackendConsumer::StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D) {
 547   if (D.getSeverity() != llvm::DS_Warning)
 548     // For now, the only support we have for StackSize diagnostic is warning.
 549     // We do not know how to format other severities.
 550     return false;
 551
 552   auto Loc = getFunctionSourceLocation(D.getFunction());
 553   if (!Loc)
 554     return false;
 555
 556   Diags.Report(*Loc, diag::warn_fe_frame_larger_than)
 557       << D.getStackSize() << D.getStackLimit()
 558       << llvm::demangle(D.getFunction().getName());
 559   return true;
 560 }
 561
 562 bool BackendConsumer::ResourceLimitDiagHandler(
 563     const llvm::DiagnosticInfoResourceLimit &D) {
 564   auto Loc = getFunctionSourceLocation(D.getFunction());
 565   if (!Loc)
 566     return false;
 567   unsigned DiagID = diag::err_fe_backend_resource_limit;
 568   ComputeDiagID(D.getSeverity(), backend_resource_limit, DiagID);
 569
 570   Diags.Report(*Loc, DiagID)
 571       << D.getResourceName() << D.getResourceSize() << D.getResourceLimit()
 572       << llvm::demangle(D.getFunction().getName());
 573   return true;
 574 }
 575
 576 const FullSourceLoc BackendConsumer::getBestLocationFromDebugLoc(
 577     const llvm::DiagnosticInfoWithLocationBase &D, bool &BadDebugInfo,
 578     StringRef &Filename, unsigned &Line, unsigned &Column) const {
 579   SourceManager &SourceMgr = Context->getSourceManager();
 580   FileManager &FileMgr = SourceMgr.getFileManager();
 581   SourceLocation DILoc;
 582
 583   if (D.isLocationAvailable()) {
 584     D.getLocation(Filename, Line, Column);
 585     if (Line > 0) {
 586       auto FE = FileMgr.getOptionalFileRef(Filename);
 587       if (!FE)
 588         FE = FileMgr.getOptionalFileRef(D.getAbsolutePath());
 589       if (FE) {
 590         // If -gcolumn-info was not used, Column will be 0. This upsets the
 591         // source manager, so pass 1 if Column is not set.
 592         DILoc = SourceMgr.translateFileLineCol(*FE, Line, Column ? Column : 1);
 593       }
 594     }
 595     BadDebugInfo = DILoc.isInvalid();
 596   }
 597
 598   // If a location isn't available, try to approximate it using the associated
 599   // function definition. We use the definition's right brace to differentiate
 600   // from diagnostics that genuinely relate to the function itself.
 601   FullSourceLoc Loc(DILoc, SourceMgr);
 602   if (Loc.isInvalid()) {
 603     if (auto MaybeLoc = getFunctionSourceLocation(D.getFunction()))
 604       Loc = *MaybeLoc;
 605   }
 606
 607   if (DILoc.isInvalid() && D.isLocationAvailable())
 608     // If we were not able to translate the file:line:col information
 609     // back to a SourceLocation, at least emit a note stating that
 610     // we could not translate this location. This can happen in the
 611     // case of #line directives.
 612     Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
 613         << Filename << Line << Column;
 614
 615   return Loc;
 616 }
 617
 618 std::optional<FullSourceLoc>
 619 BackendConsumer::getFunctionSourceLocation(const Function &F) const {
 620   auto Hash = llvm::hash_value(F.getName());
 621   for (const auto &Pair : ManglingFullSourceLocs) {
 622     if (Pair.first == Hash)
 623       return Pair.second;
 624   }
 625   return std::nullopt;
 626 }
 627
 628 void BackendConsumer::UnsupportedDiagHandler(
 629     const llvm::DiagnosticInfoUnsupported &D) {
 630   // We only support warnings or errors.
 631   assert(D.getSeverity() == llvm::DS_Error ||
 632          D.getSeverity() == llvm::DS_Warning);
 633
 634   StringRef Filename;
 635   unsigned Line, Column;
 636   bool BadDebugInfo = false;
 637   FullSourceLoc Loc;
 638   std::string Msg;
 639   raw_string_ostream MsgStream(Msg);
 640
 641   // Context will be nullptr for IR input files, we will construct the diag
 642   // message from llvm::DiagnosticInfoUnsupported.
 643   if (Context != nullptr) {
 644     Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
 645     MsgStream << D.getMessage();
 646   } else {
 647     DiagnosticPrinterRawOStream DP(MsgStream);
 648     D.print(DP);
 649   }
 650
 651   auto DiagType = D.getSeverity() == llvm::DS_Error
 652                       ? diag::err_fe_backend_unsupported
 653                       : diag::warn_fe_backend_unsupported;
 654   Diags.Report(Loc, DiagType) << Msg;
 655
 656   if (BadDebugInfo)
 657     // If we were not able to translate the file:line:col information
 658     // back to a SourceLocation, at least emit a note stating that
 659     // we could not translate this location. This can happen in the
 660     // case of #line directives.
 661     Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
 662         << Filename << Line << Column;
 663 }
 664
 665 void BackendConsumer::EmitOptimizationMessage(
 666     const llvm::DiagnosticInfoOptimizationBase &D, unsigned DiagID) {
 667   // We only support warnings and remarks.
 668   assert(D.getSeverity() == llvm::DS_Remark ||
 669          D.getSeverity() == llvm::DS_Warning);
 670
 671   StringRef Filename;
 672   unsigned Line, Column;
 673   bool BadDebugInfo = false;
 674   FullSourceLoc Loc;
 675   std::string Msg;
 676   raw_string_ostream MsgStream(Msg);
 677
 678   // Context will be nullptr for IR input files, we will construct the remark
 679   // message from llvm::DiagnosticInfoOptimizationBase.
 680   if (Context != nullptr) {
 681     Loc = getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
 682     MsgStream << D.getMsg();
 683   } else {
 684     DiagnosticPrinterRawOStream DP(MsgStream);
 685     D.print(DP);
 686   }
 687
 688   if (D.getHotness())
 689     MsgStream << " (hotness: " << *D.getHotness() << ")";
 690
 691   Diags.Report(Loc, DiagID) << AddFlagValue(D.getPassName()) << Msg;
 692
 693   if (BadDebugInfo)
 694     // If we were not able to translate the file:line:col information
 695     // back to a SourceLocation, at least emit a note stating that
 696     // we could not translate this location. This can happen in the
 697     // case of #line directives.
 698     Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
 699         << Filename << Line << Column;
 700 }
 701
 702 void BackendConsumer::OptimizationRemarkHandler(
 703     const llvm::DiagnosticInfoOptimizationBase &D) {
 704   // Without hotness information, don't show noisy remarks.
 705   if (D.isVerbose() && !D.getHotness())
 706     return;
 707
 708   if (D.isPassed()) {
 709     // Optimization remarks are active only if the -Rpass flag has a regular
 710     // expression that matches the name of the pass name in \p D.
 711     if (CodeGenOpts.OptimizationRemark.patternMatches(D.getPassName()))
 712       EmitOptimizationMessage(D, diag::remark_fe_backend_optimization_remark);
 713   } else if (D.isMissed()) {
 714     // Missed optimization remarks are active only if the -Rpass-missed
 715     // flag has a regular expression that matches the name of the pass
 716     // name in \p D.
 717     if (CodeGenOpts.OptimizationRemarkMissed.patternMatches(D.getPassName()))
 718       EmitOptimizationMessage(
 719           D, diag::remark_fe_backend_optimization_remark_missed);
 720   } else {
 721     assert(D.isAnalysis() && "Unknown remark type");
 722
 723     bool ShouldAlwaysPrint = false;
 724     if (auto *ORA = dyn_cast<llvm::OptimizationRemarkAnalysis>(&D))
 725       ShouldAlwaysPrint = ORA->shouldAlwaysPrint();
 726
 727     if (ShouldAlwaysPrint ||
 728         CodeGenOpts.OptimizationRemarkAnalysis.patternMatches(D.getPassName()))
 729       EmitOptimizationMessage(
 730           D, diag::remark_fe_backend_optimization_remark_analysis);
 731   }
 732 }
 733
 734 void BackendConsumer::OptimizationRemarkHandler(
 735     const llvm::OptimizationRemarkAnalysisFPCommute &D) {
 736   // Optimization analysis remarks are active if the pass name is set to
 737   // llvm::DiagnosticInfo::AlwasyPrint or if the -Rpass-analysis flag has a
 738   // regular expression that matches the name of the pass name in \p D.
 739
 740   if (D.shouldAlwaysPrint() ||
 741       CodeGenOpts.OptimizationRemarkAnalysis.patternMatches(D.getPassName()))
 742     EmitOptimizationMessage(
 743         D, diag::remark_fe_backend_optimization_remark_analysis_fpcommute);
 744 }
 745
 746 void BackendConsumer::OptimizationRemarkHandler(
 747     const llvm::OptimizationRemarkAnalysisAliasing &D) {
 748   // Optimization analysis remarks are active if the pass name is set to
 749   // llvm::DiagnosticInfo::AlwasyPrint or if the -Rpass-analysis flag has a
 750   // regular expression that matches the name of the pass name in \p D.
 751
 752   if (D.shouldAlwaysPrint() ||
 753       CodeGenOpts.OptimizationRemarkAnalysis.patternMatches(D.getPassName()))
 754     EmitOptimizationMessage(
 755         D, diag::remark_fe_backend_optimization_remark_analysis_aliasing);
 756 }
 757
 758 void BackendConsumer::OptimizationFailureHandler(
 759     const llvm::DiagnosticInfoOptimizationFailure &D) {
 760   EmitOptimizationMessage(D, diag::warn_fe_backend_optimization_failure);
 761 }
 762
 763 void BackendConsumer::DontCallDiagHandler(const DiagnosticInfoDontCall &D) {
 764   SourceLocation LocCookie =
 765       SourceLocation::getFromRawEncoding(D.getLocCookie());
 766
 767   // FIXME: we can't yet diagnose indirect calls. When/if we can, we
 768   // should instead assert that LocCookie.isValid().
 769   if (!LocCookie.isValid())
 770     return;
 771
 772   Diags.Report(LocCookie, D.getSeverity() == DiagnosticSeverity::DS_Error
 773                               ? diag::err_fe_backend_error_attr
 774                               : diag::warn_fe_backend_warning_attr)
 775       << llvm::demangle(D.getFunctionName()) << D.getNote();
 776 }
 777
 778 void BackendConsumer::MisExpectDiagHandler(
 779     const llvm::DiagnosticInfoMisExpect &D) {
 780   StringRef Filename;
 781   unsigned Line, Column;
 782   bool BadDebugInfo = false;
 783   FullSourceLoc Loc =
 784       getBestLocationFromDebugLoc(D, BadDebugInfo, Filename, Line, Column);
 785
 786   Diags.Report(Loc, diag::warn_profile_data_misexpect) << D.getMsg().str();
 787
 788   if (BadDebugInfo)
 789     // If we were not able to translate the file:line:col information
 790     // back to a SourceLocation, at least emit a note stating that
 791     // we could not translate this location. This can happen in the
 792     // case of #line directives.
 793     Diags.Report(Loc, diag::note_fe_backend_invalid_loc)
 794         << Filename << Line << Column;
 795 }
 796
 797 /// This function is invoked when the backend needs
 798 /// to report something to the user.
 799 void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
 800   unsigned DiagID = diag::err_fe_inline_asm;
 801   llvm::DiagnosticSeverity Severity = DI.getSeverity();
 802   // Get the diagnostic ID based.
 803   switch (DI.getKind()) {
 804   case llvm::DK_InlineAsm:
 805     if (InlineAsmDiagHandler(cast<DiagnosticInfoInlineAsm>(DI)))
 806       return;
 807     ComputeDiagID(Severity, inline_asm, DiagID);
 808     break;
 809   case llvm::DK_SrcMgr:
 810     SrcMgrDiagHandler(cast<DiagnosticInfoSrcMgr>(DI));
 811     return;
 812   case llvm::DK_StackSize:
 813     if (StackSizeDiagHandler(cast<DiagnosticInfoStackSize>(DI)))
 814       return;
 815     ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
 816     break;
 817   case llvm::DK_ResourceLimit:
 818     if (ResourceLimitDiagHandler(cast<DiagnosticInfoResourceLimit>(DI)))
 819       return;
 820     ComputeDiagID(Severity, backend_resource_limit, DiagID);
 821     break;
 822   case DK_Linker:
 823     ComputeDiagID(Severity, linking_module, DiagID);
 824     break;
 825   case llvm::DK_OptimizationRemark:
 826     // Optimization remarks are always handled completely by this
 827     // handler. There is no generic way of emitting them.
 828     OptimizationRemarkHandler(cast<OptimizationRemark>(DI));
 829     return;
 830   case llvm::DK_OptimizationRemarkMissed:
 831     // Optimization remarks are always handled completely by this
 832     // handler. There is no generic way of emitting them.
 833     OptimizationRemarkHandler(cast<OptimizationRemarkMissed>(DI));
 834     return;
 835   case llvm::DK_OptimizationRemarkAnalysis:
 836     // Optimization remarks are always handled completely by this
 837     // handler. There is no generic way of emitting them.
 838     OptimizationRemarkHandler(cast<OptimizationRemarkAnalysis>(DI));
 839     return;
 840   case llvm::DK_OptimizationRemarkAnalysisFPCommute:
 841     // Optimization remarks are always handled completely by this
 842     // handler. There is no generic way of emitting them.
 843     OptimizationRemarkHandler(cast<OptimizationRemarkAnalysisFPCommute>(DI));
 844     return;
 845   case llvm::DK_OptimizationRemarkAnalysisAliasing:
 846     // Optimization remarks are always handled completely by this
 847     // handler. There is no generic way of emitting them.
 848     OptimizationRemarkHandler(cast<OptimizationRemarkAnalysisAliasing>(DI));
 849     return;
 850   case llvm::DK_MachineOptimizationRemark:
 851     // Optimization remarks are always handled completely by this
 852     // handler. There is no generic way of emitting them.
 853     OptimizationRemarkHandler(cast<MachineOptimizationRemark>(DI));
 854     return;
 855   case llvm::DK_MachineOptimizationRemarkMissed:
 856     // Optimization remarks are always handled completely by this
 857     // handler. There is no generic way of emitting them.
 858     OptimizationRemarkHandler(cast<MachineOptimizationRemarkMissed>(DI));
 859     return;
 860   case llvm::DK_MachineOptimizationRemarkAnalysis:
 861     // Optimization remarks are always handled completely by this
 862     // handler. There is no generic way of emitting them.
 863     OptimizationRemarkHandler(cast<MachineOptimizationRemarkAnalysis>(DI));
 864     return;
 865   case llvm::DK_OptimizationFailure:
 866     // Optimization failures are always handled completely by this
 867     // handler.
 868     OptimizationFailureHandler(cast<DiagnosticInfoOptimizationFailure>(DI));
 869     return;
 870   case llvm::DK_Unsupported:
 871     UnsupportedDiagHandler(cast<DiagnosticInfoUnsupported>(DI));
 872     return;
 873   case llvm::DK_DontCall:
 874     DontCallDiagHandler(cast<DiagnosticInfoDontCall>(DI));
 875     return;
 876   case llvm::DK_MisExpect:
 877     MisExpectDiagHandler(cast<DiagnosticInfoMisExpect>(DI));
 878     return;
 879   default:
 880     // Plugin IDs are not bound to any value as they are set dynamically.
 881     ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
 882     break;
 883   }
 884   std::string MsgStorage;
 885   {
 886     raw_string_ostream Stream(MsgStorage);
 887     DiagnosticPrinterRawOStream DP(Stream);
 888     DI.print(DP);
 889   }
 890
 891   if (DI.getKind() == DK_Linker) {
 892     assert(CurLinkModule && "CurLinkModule must be set for linker diagnostics");
 893     Diags.Report(DiagID) << CurLinkModule->getModuleIdentifier() << MsgStorage;
 894     return;
 895   }
 896
 897   // Report the backend message using the usual diagnostic mechanism.
 898   FullSourceLoc Loc;
 899   Diags.Report(Loc, DiagID).AddString(MsgStorage);
 900 }
 901 #undef ComputeDiagID
 902
 903 CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
 904     : Act(_Act), VMContext(_VMContext ? _VMContext : new LLVMContext),
 905       OwnsVMContext(!_VMContext) {}
 906
 907 CodeGenAction::~CodeGenAction() {
 908   TheModule.reset();
 909   if (OwnsVMContext)
 910     delete VMContext;
 911 }
 912
 913 bool CodeGenAction::loadLinkModules(CompilerInstance &CI) {
 914   if (!LinkModules.empty())
 915     return false;
 916
 917   for (const CodeGenOptions::BitcodeFileToLink &F :
 918        CI.getCodeGenOpts().LinkBitcodeFiles) {
 919     auto BCBuf = CI.getFileManager().getBufferForFile(F.Filename);
 920     if (!BCBuf) {
 921       CI.getDiagnostics().Report(diag::err_cannot_open_file)
 922           << F.Filename << BCBuf.getError().message();
 923       LinkModules.clear();
 924       return true;
 925     }
 926
 927     Expected<std::unique_ptr<llvm::Module>> ModuleOrErr =
 928         getOwningLazyBitcodeModule(std::move(*BCBuf), *VMContext);
 929     if (!ModuleOrErr) {
 930       handleAllErrors(ModuleOrErr.takeError(), [&](ErrorInfoBase &EIB) {
 931         CI.getDiagnostics().Report(diag::err_cannot_open_file)
 932             << F.Filename << EIB.message();
 933       });
 934       LinkModules.clear();
 935       return true;
 936     }
 937     LinkModules.push_back({std::move(ModuleOrErr.get()), F.PropagateAttrs,
 938                            F.Internalize, F.LinkFlags});
 939   }
 940   return false;
 941 }
 942
 943 bool CodeGenAction::hasIRSupport() const { return true; }
 944
 945 void CodeGenAction::EndSourceFileAction() {
 946   // If the consumer creation failed, do nothing.
 947   if (!getCompilerInstance().hasASTConsumer())
 948     return;
 949
 950   // Steal the module from the consumer.
 951   TheModule = BEConsumer->takeModule();
 952 }
 953
 954 std::unique_ptr<llvm::Module> CodeGenAction::takeModule() {
 955   return std::move(TheModule);
 956 }
 957
 958 llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
 959   OwnsVMContext = false;
 960   return VMContext;
 961 }
 962
 963 CodeGenerator *CodeGenAction::getCodeGenerator() const {
 964   return BEConsumer->getCodeGenerator();
 965 }
 966
 967 bool CodeGenAction::BeginSourceFileAction(CompilerInstance &CI) {
 968   if (CI.getFrontendOpts().GenReducedBMI)
 969     CI.getLangOpts().setCompilingModule(LangOptions::CMK_ModuleInterface);
 970   return true;
 971 }
 972
 973 static std::unique_ptr<raw_pwrite_stream>
 974 GetOutputStream(CompilerInstance &CI, StringRef InFile, BackendAction Action) {
 975   switch (Action) {
 976   case Backend_EmitAssembly:
 977     return CI.createDefaultOutputFile(false, InFile, "s");
 978   case Backend_EmitLL:
 979     return CI.createDefaultOutputFile(false, InFile, "ll");
 980   case Backend_EmitBC:
 981     return CI.createDefaultOutputFile(true, InFile, "bc");
 982   case Backend_EmitNothing:
 983     return nullptr;
 984   case Backend_EmitMCNull:
 985     return CI.createNullOutputFile();
 986   case Backend_EmitObj:
 987     return CI.createDefaultOutputFile(true, InFile, "o");
 988   }
 989
 990   llvm_unreachable("Invalid action!");
 991 }
 992
 993 std::unique_ptr<ASTConsumer>
 994 CodeGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
 995   BackendAction BA = static_cast<BackendAction>(Act);
 996   std::unique_ptr<raw_pwrite_stream> OS = CI.takeOutputStream();
 997   if (!OS)
 998     OS = GetOutputStream(CI, InFile, BA);
 999
1000   if (BA != Backend_EmitNothing && !OS)
1001     return nullptr;
1002
1003   // Load bitcode modules to link with, if we need to.
1004   if (loadLinkModules(CI))
1005     return nullptr;
1006
1007   CoverageSourceInfo *CoverageInfo = nullptr;
1008   // Add the preprocessor callback only when the coverage mapping is generated.
1009   if (CI.getCodeGenOpts().CoverageMapping)
1010     CoverageInfo = CodeGen::CoverageMappingModuleGen::setUpCoverageCallbacks(
1011         CI.getPreprocessor());
1012
1013   std::unique_ptr<BackendConsumer> Result(new BackendConsumer(
1014       BA, CI.getDiagnostics(), &CI.getVirtualFileSystem(),
1015       CI.getHeaderSearchOpts(), CI.getPreprocessorOpts(), CI.getCodeGenOpts(),
1016       CI.getTargetOpts(), CI.getLangOpts(), std::string(InFile),
1017       std::move(LinkModules), std::move(OS), *VMContext, CoverageInfo));
1018   BEConsumer = Result.get();
1019
1020   // Enable generating macro debug info only when debug info is not disabled and
1021   // also macro debug info is enabled.
1022   if (CI.getCodeGenOpts().getDebugInfo() != codegenoptions::NoDebugInfo &&
1023       CI.getCodeGenOpts().MacroDebugInfo) {
1024     std::unique_ptr<PPCallbacks> Callbacks =
1025         std::make_unique<MacroPPCallbacks>(BEConsumer->getCodeGenerator(),
1026                                             CI.getPreprocessor());
1027     CI.getPreprocessor().addPPCallbacks(std::move(Callbacks));
1028   }
1029
1030   if (CI.getFrontendOpts().GenReducedBMI &&
1031       !CI.getFrontendOpts().ModuleOutputPath.empty()) {
1032     std::vector<std::unique_ptr<ASTConsumer>> Consumers(2);
1033     Consumers[0] = std::make_unique<ReducedBMIGenerator>(
1034         CI.getPreprocessor(), CI.getModuleCache(),
1035         CI.getFrontendOpts().ModuleOutputPath);
1036     Consumers[1] = std::move(Result);
1037     return std::make_unique<MultiplexConsumer>(std::move(Consumers));
1038   }
1039
1040   return std::move(Result);
1041 }
1042
1043 std::unique_ptr<llvm::Module>
1044 CodeGenAction::loadModule(MemoryBufferRef MBRef) {
1045   CompilerInstance &CI = getCompilerInstance();
1046   SourceManager &SM = CI.getSourceManager();
1047
1048   auto DiagErrors = [&](Error E) -> std::unique_ptr<llvm::Module> {
1049     unsigned DiagID =
1050         CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
1051     handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
1052       CI.getDiagnostics().Report(DiagID) << EIB.message();
1053     });
1054     return {};
1055   };
1056
1057   // For ThinLTO backend invocations, ensure that the context
1058   // merges types based on ODR identifiers. We also need to read
1059   // the correct module out of a multi-module bitcode file.
1060   if (!CI.getCodeGenOpts().ThinLTOIndexFile.empty()) {
1061     VMContext->enableDebugTypeODRUniquing();
1062
1063     Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1064     if (!BMsOrErr)
1065       return DiagErrors(BMsOrErr.takeError());
1066     BitcodeModule *Bm = llvm::lto::findThinLTOModule(*BMsOrErr);
1067     // We have nothing to do if the file contains no ThinLTO module. This is
1068     // possible if ThinLTO compilation was not able to split module. Content of
1069     // the file was already processed by indexing and will be passed to the
1070     // linker using merged object file.
1071     if (!Bm) {
1072       auto M = std::make_unique<llvm::Module>("empty", *VMContext);
1073       M->setTargetTriple(CI.getTargetOpts().Triple);
1074       return M;
1075     }
1076     Expected<std::unique_ptr<llvm::Module>> MOrErr =
1077         Bm->parseModule(*VMContext);
1078     if (!MOrErr)
1079       return DiagErrors(MOrErr.takeError());
1080     return std::move(*MOrErr);
1081   }
1082
1083   // Load bitcode modules to link with, if we need to.
1084   if (loadLinkModules(CI))
1085     return nullptr;
1086
1087   // Handle textual IR and bitcode file with one single module.
1088   llvm::SMDiagnostic Err;
1089   if (std::unique_ptr<llvm::Module> M = parseIR(MBRef, Err, *VMContext))
1090     return M;
1091
1092   // If MBRef is a bitcode with multiple modules (e.g., -fsplit-lto-unit
1093   // output), place the extra modules (actually only one, a regular LTO module)
1094   // into LinkModules as if we are using -mlink-bitcode-file.
1095   Expected<std::vector<BitcodeModule>> BMsOrErr = getBitcodeModuleList(MBRef);
1096   if (BMsOrErr && BMsOrErr->size()) {
1097     std::unique_ptr<llvm::Module> FirstM;
1098     for (auto &BM : *BMsOrErr) {
1099       Expected<std::unique_ptr<llvm::Module>> MOrErr =
1100           BM.parseModule(*VMContext);
1101       if (!MOrErr)
1102         return DiagErrors(MOrErr.takeError());
1103       if (FirstM)
1104         LinkModules.push_back({std::move(*MOrErr), /*PropagateAttrs=*/false,
1105                                /*Internalize=*/false, /*LinkFlags=*/{}});
1106       else
1107         FirstM = std::move(*MOrErr);
1108     }
1109     if (FirstM)
1110       return FirstM;
1111   }
1112   // If BMsOrErr fails, consume the error and use the error message from
1113   // parseIR.
1114   consumeError(BMsOrErr.takeError());
1115
1116   // Translate from the diagnostic info to the SourceManager location if
1117   // available.
1118   // TODO: Unify this with ConvertBackendLocation()
1119   SourceLocation Loc;
1120   if (Err.getLineNo() > 0) {
1121     assert(Err.getColumnNo() >= 0);
1122     Loc = SM.translateFileLineCol(SM.getFileEntryForID(SM.getMainFileID()),
1123                                   Err.getLineNo(), Err.getColumnNo() + 1);
1124   }
1125
1126   // Strip off a leading diagnostic code if there is one.
1127   StringRef Msg = Err.getMessage();
1128   Msg.consume_front("error: ");
1129
1130   unsigned DiagID =
1131       CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
1132
1133   CI.getDiagnostics().Report(Loc, DiagID) << Msg;
1134   return {};
1135 }
1136
1137 void CodeGenAction::ExecuteAction() {
1138   if (getCurrentFileKind().getLanguage() != Language::LLVM_IR) {
1139     this->ASTFrontendAction::ExecuteAction();
1140     return;
1141   }
1142
1143   // If this is an IR file, we have to treat it specially.
1144   BackendAction BA = static_cast<BackendAction>(Act);
1145   CompilerInstance &CI = getCompilerInstance();
1146   auto &CodeGenOpts = CI.getCodeGenOpts();
1147   auto &Diagnostics = CI.getDiagnostics();
1148   std::unique_ptr<raw_pwrite_stream> OS =
1149       GetOutputStream(CI, getCurrentFileOrBufferName(), BA);
1150   if (BA != Backend_EmitNothing && !OS)
1151     return;
1152
1153   SourceManager &SM = CI.getSourceManager();
1154   FileID FID = SM.getMainFileID();
1155   std::optional<MemoryBufferRef> MainFile = SM.getBufferOrNone(FID);
1156   if (!MainFile)
1157     return;
1158
1159   TheModule = loadModule(*MainFile);
1160   if (!TheModule)
1161     return;
1162
1163   const TargetOptions &TargetOpts = CI.getTargetOpts();
1164   if (TheModule->getTargetTriple() != TargetOpts.Triple) {
1165     Diagnostics.Report(SourceLocation(), diag::warn_fe_override_module)
1166         << TargetOpts.Triple;
1167     TheModule->setTargetTriple(TargetOpts.Triple);
1168   }
1169
1170   EmbedObject(TheModule.get(), CodeGenOpts, Diagnostics);
1171   EmbedBitcode(TheModule.get(), CodeGenOpts, *MainFile);
1172
1173   LLVMContext &Ctx = TheModule->getContext();
1174
1175   // Restore any diagnostic handler previously set before returning from this
1176   // function.
1177   struct RAII {
1178     LLVMContext &Ctx;
1179     std::unique_ptr<DiagnosticHandler> PrevHandler = Ctx.getDiagnosticHandler();
1180     ~RAII() { Ctx.setDiagnosticHandler(std::move(PrevHandler)); }
1181   } _{Ctx};
1182
1183   // Set clang diagnostic handler. To do this we need to create a fake
1184   // BackendConsumer.
1185   BackendConsumer Result(BA, CI.getDiagnostics(), &CI.getVirtualFileSystem(),
1186                          CI.getHeaderSearchOpts(), CI.getPreprocessorOpts(),
1187                          CI.getCodeGenOpts(), CI.getTargetOpts(),
1188                          CI.getLangOpts(), TheModule.get(),
1189                          std::move(LinkModules), *VMContext, nullptr);
1190
1191   // Link in each pending link module.
1192   if (!CodeGenOpts.LinkBitcodePostopt && Result.LinkInModules(&*TheModule))
1193     return;
1194
1195   // PR44896: Force DiscardValueNames as false. DiscardValueNames cannot be
1196   // true here because the valued names are needed for reading textual IR.
1197   Ctx.setDiscardValueNames(false);
1198   Ctx.setDiagnosticHandler(
1199       std::make_unique<ClangDiagnosticHandler>(CodeGenOpts, &Result));
1200
1201   Ctx.setDefaultTargetCPU(TargetOpts.CPU);
1202   Ctx.setDefaultTargetFeatures(llvm::join(TargetOpts.Features, ","));
1203
1204   Expected<std::unique_ptr<llvm::ToolOutputFile>> OptRecordFileOrErr =
1205       setupLLVMOptimizationRemarks(
1206           Ctx, CodeGenOpts.OptRecordFile, CodeGenOpts.OptRecordPasses,
1207           CodeGenOpts.OptRecordFormat, CodeGenOpts.DiagnosticsWithHotness,
1208           CodeGenOpts.DiagnosticsHotnessThreshold);
1209
1210   if (Error E = OptRecordFileOrErr.takeError()) {
1211     reportOptRecordError(std::move(E), Diagnostics, CodeGenOpts);
1212     return;
1213   }
1214   std::unique_ptr<llvm::ToolOutputFile> OptRecordFile =
1215       std::move(*OptRecordFileOrErr);
1216
1217   EmitBackendOutput(
1218       Diagnostics, CI.getHeaderSearchOpts(), CodeGenOpts, TargetOpts,
1219       CI.getLangOpts(), CI.getTarget().getDataLayoutString(), TheModule.get(),
1220       BA, CI.getFileManager().getVirtualFileSystemPtr(), std::move(OS));
1221   if (OptRecordFile)
1222     OptRecordFile->keep();
1223 }
1224
1225 //
1226
1227 void EmitAssemblyAction::anchor() { }
1228 EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
1229   : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
1230
1231 void EmitBCAction::anchor() { }
1232 EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
1233   : CodeGenAction(Backend_EmitBC, _VMContext) {}
1234
1235 void EmitLLVMAction::anchor() { }
1236 EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
1237   : CodeGenAction(Backend_EmitLL, _VMContext) {}
1238
1239 void EmitLLVMOnlyAction::anchor() { }
1240 EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
1241   : CodeGenAction(Backend_EmitNothing, _VMContext) {}
1242
1243 void EmitCodeGenOnlyAction::anchor() { }
1244 EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
1245   : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
1246
1247 void EmitObjAction::anchor() { }
1248 EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
1249   : CodeGenAction(Backend_EmitObj, _VMContext) {}