1 //===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "CoverageMappingGen.h"
11 #include "clang/CodeGen/CodeGenAction.h"
12 #include "clang/AST/ASTConsumer.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclGroup.h"
15 #include "clang/AST/DeclCXX.h"
16 #include "clang/Basic/FileManager.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Basic/TargetInfo.h"
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/CodeGen/BackendUtil.h"
21 #include "clang/CodeGen/ModuleBuilder.h"
22 #include "clang/Frontend/CompilerInstance.h"
23 #include "clang/Frontend/FrontendDiagnostic.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/Bitcode/ReaderWriter.h"
26 #include "llvm/IR/DebugInfo.h"
27 #include "llvm/IR/DiagnosticInfo.h"
28 #include "llvm/IR/DiagnosticPrinter.h"
29 #include "llvm/IR/LLVMContext.h"
30 #include "llvm/IR/Module.h"
31 #include "llvm/IRReader/IRReader.h"
32 #include "llvm/Linker/Linker.h"
33 #include "llvm/Pass.h"
34 #include "llvm/Support/MemoryBuffer.h"
35 #include "llvm/Support/SourceMgr.h"
36 #include "llvm/Support/Timer.h"
37 #include <memory>
38 using namespace clang;
39 using namespace llvm;
40 
41 namespace clang {
42   class BackendConsumer : public ASTConsumer {
43     virtual void anchor();
44     DiagnosticsEngine &Diags;
45     BackendAction Action;
46     const CodeGenOptions &CodeGenOpts;
47     const TargetOptions &TargetOpts;
48     const LangOptions &LangOpts;
49     raw_ostream *AsmOutStream;
50     ASTContext *Context;
51 
52     Timer LLVMIRGeneration;
53 
54     std::unique_ptr<CodeGenerator> Gen;
55 
56     std::unique_ptr<llvm::Module> TheModule, LinkModule;
57 
58   public:
59     BackendConsumer(BackendAction action, DiagnosticsEngine &_Diags,
60                     const CodeGenOptions &compopts,
61                     const TargetOptions &targetopts,
62                     const LangOptions &langopts, bool TimePasses,
63                     const std::string &infile, llvm::Module *LinkModule,
64                     raw_ostream *OS, LLVMContext &C,
65                     CoverageSourceInfo *CoverageInfo = nullptr)
66         : Diags(_Diags), Action(action), CodeGenOpts(compopts),
67           TargetOpts(targetopts), LangOpts(langopts), AsmOutStream(OS),
68           Context(), LLVMIRGeneration("LLVM IR Generation Time"),
69           Gen(CreateLLVMCodeGen(Diags, infile, compopts,
70                                 targetopts, C, CoverageInfo)),
71           LinkModule(LinkModule) {
72       llvm::TimePassesIsEnabled = TimePasses;
73     }
74 
75     std::unique_ptr<llvm::Module> takeModule() { return std::move(TheModule); }
76     llvm::Module *takeLinkModule() { return LinkModule.release(); }
77 
78     void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
79       Gen->HandleCXXStaticMemberVarInstantiation(VD);
80     }
81 
82     void Initialize(ASTContext &Ctx) override {
83       Context = &Ctx;
84 
85       if (llvm::TimePassesIsEnabled)
86         LLVMIRGeneration.startTimer();
87 
88       Gen->Initialize(Ctx);
89 
90       TheModule.reset(Gen->GetModule());
91 
92       if (llvm::TimePassesIsEnabled)
93         LLVMIRGeneration.stopTimer();
94     }
95 
96     bool HandleTopLevelDecl(DeclGroupRef D) override {
97       PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
98                                      Context->getSourceManager(),
99                                      "LLVM IR generation of declaration");
100 
101       if (llvm::TimePassesIsEnabled)
102         LLVMIRGeneration.startTimer();
103 
104       Gen->HandleTopLevelDecl(D);
105 
106       if (llvm::TimePassesIsEnabled)
107         LLVMIRGeneration.stopTimer();
108 
109       return true;
110     }
111 
112     void HandleInlineMethodDefinition(CXXMethodDecl *D) override {
113       PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
114                                      Context->getSourceManager(),
115                                      "LLVM IR generation of inline method");
116       if (llvm::TimePassesIsEnabled)
117         LLVMIRGeneration.startTimer();
118 
119       Gen->HandleInlineMethodDefinition(D);
120 
121       if (llvm::TimePassesIsEnabled)
122         LLVMIRGeneration.stopTimer();
123     }
124 
125     void HandleTranslationUnit(ASTContext &C) override {
126       {
127         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
128         if (llvm::TimePassesIsEnabled)
129           LLVMIRGeneration.startTimer();
130 
131         Gen->HandleTranslationUnit(C);
132 
133         if (llvm::TimePassesIsEnabled)
134           LLVMIRGeneration.stopTimer();
135       }
136 
137       // Silently ignore if we weren't initialized for some reason.
138       if (!TheModule)
139         return;
140 
141       // Make sure IR generation is happy with the module. This is released by
142       // the module provider.
143       llvm::Module *M = Gen->ReleaseModule();
144       if (!M) {
145         // The module has been released by IR gen on failures, do not double
146         // free.
147         TheModule.release();
148         return;
149       }
150 
151       assert(TheModule.get() == M &&
152              "Unexpected module change during IR generation");
153 
154       // Link LinkModule into this module if present, preserving its validity.
155       if (LinkModule) {
156         std::string ErrorMsg;
157         if (Linker::LinkModules(M, LinkModule.get(), Linker::PreserveSource,
158                                 &ErrorMsg)) {
159           Diags.Report(diag::err_fe_cannot_link_module)
160             << LinkModule->getModuleIdentifier() << ErrorMsg;
161           return;
162         }
163       }
164 
165       // Install an inline asm handler so that diagnostics get printed through
166       // our diagnostics hooks.
167       LLVMContext &Ctx = TheModule->getContext();
168       LLVMContext::InlineAsmDiagHandlerTy OldHandler =
169         Ctx.getInlineAsmDiagnosticHandler();
170       void *OldContext = Ctx.getInlineAsmDiagnosticContext();
171       Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
172 
173       LLVMContext::DiagnosticHandlerTy OldDiagnosticHandler =
174           Ctx.getDiagnosticHandler();
175       void *OldDiagnosticContext = Ctx.getDiagnosticContext();
176       Ctx.setDiagnosticHandler(DiagnosticHandler, this);
177 
178       EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
179                         C.getTargetInfo().getTargetDescription(),
180                         TheModule.get(), Action, AsmOutStream);
181 
182       Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
183 
184       Ctx.setDiagnosticHandler(OldDiagnosticHandler, OldDiagnosticContext);
185     }
186 
187     void HandleTagDeclDefinition(TagDecl *D) override {
188       PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
189                                      Context->getSourceManager(),
190                                      "LLVM IR generation of declaration");
191       Gen->HandleTagDeclDefinition(D);
192     }
193 
194     void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
195       Gen->HandleTagDeclRequiredDefinition(D);
196     }
197 
198     void CompleteTentativeDefinition(VarDecl *D) override {
199       Gen->CompleteTentativeDefinition(D);
200     }
201 
202     void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) override {
203       Gen->HandleVTable(RD, DefinitionRequired);
204     }
205 
206     void HandleLinkerOptionPragma(llvm::StringRef Opts) override {
207       Gen->HandleLinkerOptionPragma(Opts);
208     }
209 
210     void HandleDetectMismatch(llvm::StringRef Name,
211                                       llvm::StringRef Value) override {
212       Gen->HandleDetectMismatch(Name, Value);
213     }
214 
215     void HandleDependentLibrary(llvm::StringRef Opts) override {
216       Gen->HandleDependentLibrary(Opts);
217     }
218 
219     static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
220                                      unsigned LocCookie) {
221       SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
222       ((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
223     }
224 
225     static void DiagnosticHandler(const llvm::DiagnosticInfo &DI,
226                                   void *Context) {
227       ((BackendConsumer *)Context)->DiagnosticHandlerImpl(DI);
228     }
229 
230     void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
231                                SourceLocation LocCookie);
232 
233     void DiagnosticHandlerImpl(const llvm::DiagnosticInfo &DI);
234     /// \brief Specialized handler for InlineAsm diagnostic.
235     /// \return True if the diagnostic has been successfully reported, false
236     /// otherwise.
237     bool InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D);
238     /// \brief Specialized handler for StackSize diagnostic.
239     /// \return True if the diagnostic has been successfully reported, false
240     /// otherwise.
241     bool StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D);
242     /// \brief Specialized handlers for optimization remarks.
243     /// Note that these handlers only accept remarks and they always handle
244     /// them.
245     void EmitOptimizationMessage(const llvm::DiagnosticInfoOptimizationBase &D,
246                                  unsigned DiagID);
247     void
248     OptimizationRemarkHandler(const llvm::DiagnosticInfoOptimizationRemark &D);
249     void OptimizationRemarkHandler(
250         const llvm::DiagnosticInfoOptimizationRemarkMissed &D);
251     void OptimizationRemarkHandler(
252         const llvm::DiagnosticInfoOptimizationRemarkAnalysis &D);
253     void OptimizationFailureHandler(
254         const llvm::DiagnosticInfoOptimizationFailure &D);
255   };
256 
257   void BackendConsumer::anchor() {}
258 }
259 
260 /// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
261 /// buffer to be a valid FullSourceLoc.
262 static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
263                                             SourceManager &CSM) {
264   // Get both the clang and llvm source managers.  The location is relative to
265   // a memory buffer that the LLVM Source Manager is handling, we need to add
266   // a copy to the Clang source manager.
267   const llvm::SourceMgr &LSM = *D.getSourceMgr();
268 
269   // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
270   // already owns its one and clang::SourceManager wants to own its one.
271   const MemoryBuffer *LBuf =
272   LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
273 
274   // Create the copy and transfer ownership to clang::SourceManager.
275   // TODO: Avoid copying files into memory.
276   std::unique_ptr<llvm::MemoryBuffer> CBuf =
277       llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
278                                            LBuf->getBufferIdentifier());
279   // FIXME: Keep a file ID map instead of creating new IDs for each location.
280   FileID FID = CSM.createFileID(std::move(CBuf));
281 
282   // Translate the offset into the file.
283   unsigned Offset = D.getLoc().getPointer() - LBuf->getBufferStart();
284   SourceLocation NewLoc =
285   CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
286   return FullSourceLoc(NewLoc, CSM);
287 }
288 
289 
290 /// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
291 /// error parsing inline asm.  The SMDiagnostic indicates the error relative to
292 /// the temporary memory buffer that the inline asm parser has set up.
293 void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
294                                             SourceLocation LocCookie) {
295   // There are a couple of different kinds of errors we could get here.  First,
296   // we re-format the SMDiagnostic in terms of a clang diagnostic.
297 
298   // Strip "error: " off the start of the message string.
299   StringRef Message = D.getMessage();
300   if (Message.startswith("error: "))
301     Message = Message.substr(7);
302 
303   // If the SMDiagnostic has an inline asm source location, translate it.
304   FullSourceLoc Loc;
305   if (D.getLoc() != SMLoc())
306     Loc = ConvertBackendLocation(D, Context->getSourceManager());
307 
308   unsigned DiagID;
309   switch (D.getKind()) {
310   case llvm::SourceMgr::DK_Error:
311     DiagID = diag::err_fe_inline_asm;
312     break;
313   case llvm::SourceMgr::DK_Warning:
314     DiagID = diag::warn_fe_inline_asm;
315     break;
316   case llvm::SourceMgr::DK_Note:
317     DiagID = diag::note_fe_inline_asm;
318     break;
319   }
320   // If this problem has clang-level source location information, report the
321   // issue in the source with a note showing the instantiated
322   // code.
323   if (LocCookie.isValid()) {
324     Diags.Report(LocCookie, DiagID).AddString(Message);
325 
326     if (D.getLoc().isValid()) {
327       DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
328       // Convert the SMDiagnostic ranges into SourceRange and attach them
329       // to the diagnostic.
330       for (unsigned i = 0, e = D.getRanges().size(); i != e; ++i) {
331         std::pair<unsigned, unsigned> Range = D.getRanges()[i];
332         unsigned Column = D.getColumnNo();
333         B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
334                          Loc.getLocWithOffset(Range.second - Column));
335       }
336     }
337     return;
338   }
339 
340   // Otherwise, report the backend issue as occurring in the generated .s file.
341   // If Loc is invalid, we still need to report the issue, it just gets no
342   // location info.
343   Diags.Report(Loc, DiagID).AddString(Message);
344 }
345 
346 #define ComputeDiagID(Severity, GroupName, DiagID)                             \
347   do {                                                                         \
348     switch (Severity) {                                                        \
349     case llvm::DS_Error:                                                       \
350       DiagID = diag::err_fe_##GroupName;                                       \
351       break;                                                                   \
352     case llvm::DS_Warning:                                                     \
353       DiagID = diag::warn_fe_##GroupName;                                      \
354       break;                                                                   \
355     case llvm::DS_Remark:                                                      \
356       llvm_unreachable("'remark' severity not expected");                      \
357       break;                                                                   \
358     case llvm::DS_Note:                                                        \
359       DiagID = diag::note_fe_##GroupName;                                      \
360       break;                                                                   \
361     }                                                                          \
362   } while (false)
363 
364 #define ComputeDiagRemarkID(Severity, GroupName, DiagID)                       \
365   do {                                                                         \
366     switch (Severity) {                                                        \
367     case llvm::DS_Error:                                                       \
368       DiagID = diag::err_fe_##GroupName;                                       \
369       break;                                                                   \
370     case llvm::DS_Warning:                                                     \
371       DiagID = diag::warn_fe_##GroupName;                                      \
372       break;                                                                   \
373     case llvm::DS_Remark:                                                      \
374       DiagID = diag::remark_fe_##GroupName;                                    \
375       break;                                                                   \
376     case llvm::DS_Note:                                                        \
377       DiagID = diag::note_fe_##GroupName;                                      \
378       break;                                                                   \
379     }                                                                          \
380   } while (false)
381 
382 bool
383 BackendConsumer::InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D) {
384   unsigned DiagID;
385   ComputeDiagID(D.getSeverity(), inline_asm, DiagID);
386   std::string Message = D.getMsgStr().str();
387 
388   // If this problem has clang-level source location information, report the
389   // issue as being a problem in the source with a note showing the instantiated
390   // code.
391   SourceLocation LocCookie =
392       SourceLocation::getFromRawEncoding(D.getLocCookie());
393   if (LocCookie.isValid())
394     Diags.Report(LocCookie, DiagID).AddString(Message);
395   else {
396     // Otherwise, report the backend diagnostic as occurring in the generated
397     // .s file.
398     // If Loc is invalid, we still need to report the diagnostic, it just gets
399     // no location info.
400     FullSourceLoc Loc;
401     Diags.Report(Loc, DiagID).AddString(Message);
402   }
403   // We handled all the possible severities.
404   return true;
405 }
406 
407 bool
408 BackendConsumer::StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D) {
409   if (D.getSeverity() != llvm::DS_Warning)
410     // For now, the only support we have for StackSize diagnostic is warning.
411     // We do not know how to format other severities.
412     return false;
413 
414   if (const Decl *ND = Gen->GetDeclForMangledName(D.getFunction().getName())) {
415     Diags.Report(ND->getASTContext().getFullLoc(ND->getLocation()),
416                  diag::warn_fe_frame_larger_than)
417         << D.getStackSize() << Decl::castToDeclContext(ND);
418     return true;
419   }
420 
421   return false;
422 }
423 
424 void BackendConsumer::EmitOptimizationMessage(
425     const llvm::DiagnosticInfoOptimizationBase &D, unsigned DiagID) {
426   // We only support warnings and remarks.
427   assert(D.getSeverity() == llvm::DS_Remark ||
428          D.getSeverity() == llvm::DS_Warning);
429 
430   SourceManager &SourceMgr = Context->getSourceManager();
431   FileManager &FileMgr = SourceMgr.getFileManager();
432   StringRef Filename;
433   unsigned Line, Column;
434   D.getLocation(&Filename, &Line, &Column);
435   SourceLocation DILoc;
436   const FileEntry *FE = FileMgr.getFile(Filename);
437   if (FE && Line > 0) {
438     // If -gcolumn-info was not used, Column will be 0. This upsets the
439     // source manager, so pass 1 if Column is not set.
440     DILoc = SourceMgr.translateFileLineCol(FE, Line, Column ? Column : 1);
441   }
442 
443   // If a location isn't available, try to approximate it using the associated
444   // function definition. We use the definition's right brace to differentiate
445   // from diagnostics that genuinely relate to the function itself.
446   FullSourceLoc Loc(DILoc, SourceMgr);
447   if (Loc.isInvalid())
448     if (const Decl *FD = Gen->GetDeclForMangledName(D.getFunction().getName()))
449       Loc = FD->getASTContext().getFullLoc(FD->getBodyRBrace());
450 
451   Diags.Report(Loc, DiagID)
452       << AddFlagValue(D.getPassName() ? D.getPassName() : "")
453       << D.getMsg().str();
454 
455   if (DILoc.isInvalid())
456     // If we were not able to translate the file:line:col information
457     // back to a SourceLocation, at least emit a note stating that
458     // we could not translate this location. This can happen in the
459     // case of #line directives.
460     Diags.Report(Loc, diag::note_fe_backend_optimization_remark_invalid_loc)
461         << Filename << Line << Column;
462 }
463 
464 void BackendConsumer::OptimizationRemarkHandler(
465     const llvm::DiagnosticInfoOptimizationRemark &D) {
466   // Optimization remarks are active only if the -Rpass flag has a regular
467   // expression that matches the name of the pass name in \p D.
468   if (CodeGenOpts.OptimizationRemarkPattern &&
469       CodeGenOpts.OptimizationRemarkPattern->match(D.getPassName()))
470     EmitOptimizationMessage(D, diag::remark_fe_backend_optimization_remark);
471 }
472 
473 void BackendConsumer::OptimizationRemarkHandler(
474     const llvm::DiagnosticInfoOptimizationRemarkMissed &D) {
475   // Missed optimization remarks are active only if the -Rpass-missed
476   // flag has a regular expression that matches the name of the pass
477   // name in \p D.
478   if (CodeGenOpts.OptimizationRemarkMissedPattern &&
479       CodeGenOpts.OptimizationRemarkMissedPattern->match(D.getPassName()))
480     EmitOptimizationMessage(D,
481                             diag::remark_fe_backend_optimization_remark_missed);
482 }
483 
484 void BackendConsumer::OptimizationRemarkHandler(
485     const llvm::DiagnosticInfoOptimizationRemarkAnalysis &D) {
486   // Optimization analysis remarks are active only if the -Rpass-analysis
487   // flag has a regular expression that matches the name of the pass
488   // name in \p D.
489   if (CodeGenOpts.OptimizationRemarkAnalysisPattern &&
490       CodeGenOpts.OptimizationRemarkAnalysisPattern->match(D.getPassName()))
491     EmitOptimizationMessage(
492         D, diag::remark_fe_backend_optimization_remark_analysis);
493 }
494 
495 void BackendConsumer::OptimizationFailureHandler(
496     const llvm::DiagnosticInfoOptimizationFailure &D) {
497   EmitOptimizationMessage(D, diag::warn_fe_backend_optimization_failure);
498 }
499 
500 /// \brief This function is invoked when the backend needs
501 /// to report something to the user.
502 void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
503   unsigned DiagID = diag::err_fe_inline_asm;
504   llvm::DiagnosticSeverity Severity = DI.getSeverity();
505   // Get the diagnostic ID based.
506   switch (DI.getKind()) {
507   case llvm::DK_InlineAsm:
508     if (InlineAsmDiagHandler(cast<DiagnosticInfoInlineAsm>(DI)))
509       return;
510     ComputeDiagID(Severity, inline_asm, DiagID);
511     break;
512   case llvm::DK_StackSize:
513     if (StackSizeDiagHandler(cast<DiagnosticInfoStackSize>(DI)))
514       return;
515     ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
516     break;
517   case llvm::DK_OptimizationRemark:
518     // Optimization remarks are always handled completely by this
519     // handler. There is no generic way of emitting them.
520     OptimizationRemarkHandler(cast<DiagnosticInfoOptimizationRemark>(DI));
521     return;
522   case llvm::DK_OptimizationRemarkMissed:
523     // Optimization remarks are always handled completely by this
524     // handler. There is no generic way of emitting them.
525     OptimizationRemarkHandler(cast<DiagnosticInfoOptimizationRemarkMissed>(DI));
526     return;
527   case llvm::DK_OptimizationRemarkAnalysis:
528     // Optimization remarks are always handled completely by this
529     // handler. There is no generic way of emitting them.
530     OptimizationRemarkHandler(
531         cast<DiagnosticInfoOptimizationRemarkAnalysis>(DI));
532     return;
533   case llvm::DK_OptimizationFailure:
534     // Optimization failures are always handled completely by this
535     // handler.
536     OptimizationFailureHandler(cast<DiagnosticInfoOptimizationFailure>(DI));
537     return;
538   default:
539     // Plugin IDs are not bound to any value as they are set dynamically.
540     ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
541     break;
542   }
543   std::string MsgStorage;
544   {
545     raw_string_ostream Stream(MsgStorage);
546     DiagnosticPrinterRawOStream DP(Stream);
547     DI.print(DP);
548   }
549 
550   // Report the backend message using the usual diagnostic mechanism.
551   FullSourceLoc Loc;
552   Diags.Report(Loc, DiagID).AddString(MsgStorage);
553 }
554 #undef ComputeDiagID
555 
556 CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
557   : Act(_Act), LinkModule(nullptr),
558     VMContext(_VMContext ? _VMContext : new LLVMContext),
559     OwnsVMContext(!_VMContext) {}
560 
561 CodeGenAction::~CodeGenAction() {
562   TheModule.reset();
563   if (OwnsVMContext)
564     delete VMContext;
565 }
566 
567 bool CodeGenAction::hasIRSupport() const { return true; }
568 
569 void CodeGenAction::EndSourceFileAction() {
570   // If the consumer creation failed, do nothing.
571   if (!getCompilerInstance().hasASTConsumer())
572     return;
573 
574   // If we were given a link module, release consumer's ownership of it.
575   if (LinkModule)
576     BEConsumer->takeLinkModule();
577 
578   // Steal the module from the consumer.
579   TheModule = BEConsumer->takeModule();
580 }
581 
582 std::unique_ptr<llvm::Module> CodeGenAction::takeModule() {
583   return std::move(TheModule);
584 }
585 
586 llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
587   OwnsVMContext = false;
588   return VMContext;
589 }
590 
591 static raw_ostream *GetOutputStream(CompilerInstance &CI,
592                                     StringRef InFile,
593                                     BackendAction Action) {
594   switch (Action) {
595   case Backend_EmitAssembly:
596     return CI.createDefaultOutputFile(false, InFile, "s");
597   case Backend_EmitLL:
598     return CI.createDefaultOutputFile(false, InFile, "ll");
599   case Backend_EmitBC:
600     return CI.createDefaultOutputFile(true, InFile, "bc");
601   case Backend_EmitNothing:
602     return nullptr;
603   case Backend_EmitMCNull:
604     return CI.createNullOutputFile();
605   case Backend_EmitObj:
606     return CI.createDefaultOutputFile(true, InFile, "o");
607   }
608 
609   llvm_unreachable("Invalid action!");
610 }
611 
612 std::unique_ptr<ASTConsumer>
613 CodeGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
614   BackendAction BA = static_cast<BackendAction>(Act);
615   std::unique_ptr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
616   if (BA != Backend_EmitNothing && !OS)
617     return nullptr;
618 
619   llvm::Module *LinkModuleToUse = LinkModule;
620 
621   // If we were not given a link module, and the user requested that one be
622   // loaded from bitcode, do so now.
623   const std::string &LinkBCFile = CI.getCodeGenOpts().LinkBitcodeFile;
624   if (!LinkModuleToUse && !LinkBCFile.empty()) {
625     std::string ErrorStr;
626 
627     std::unique_ptr<llvm::MemoryBuffer> BCBuf =
628       CI.getFileManager().getBufferForFile(LinkBCFile, &ErrorStr);
629     if (!BCBuf) {
630       CI.getDiagnostics().Report(diag::err_cannot_open_file)
631         << LinkBCFile << ErrorStr;
632       return nullptr;
633     }
634 
635     ErrorOr<llvm::Module *> ModuleOrErr =
636         getLazyBitcodeModule(std::move(BCBuf), *VMContext);
637     if (std::error_code EC = ModuleOrErr.getError()) {
638       CI.getDiagnostics().Report(diag::err_cannot_open_file)
639         << LinkBCFile << EC.message();
640       return nullptr;
641     }
642     LinkModuleToUse = ModuleOrErr.get();
643   }
644 
645   CoverageSourceInfo *CoverageInfo = nullptr;
646   // Add the preprocessor callback only when the coverage mapping is generated.
647   if (CI.getCodeGenOpts().CoverageMapping) {
648     CoverageInfo = new CoverageSourceInfo;
649     CI.getPreprocessor().addPPCallbacks(
650                                     std::unique_ptr<PPCallbacks>(CoverageInfo));
651   }
652   std::unique_ptr<BackendConsumer> Result(new BackendConsumer(
653       BA, CI.getDiagnostics(), CI.getCodeGenOpts(), CI.getTargetOpts(),
654       CI.getLangOpts(), CI.getFrontendOpts().ShowTimers, InFile,
655       LinkModuleToUse, OS.release(), *VMContext, CoverageInfo));
656   BEConsumer = Result.get();
657   return std::move(Result);
658 }
659 
660 void CodeGenAction::ExecuteAction() {
661   // If this is an IR file, we have to treat it specially.
662   if (getCurrentFileKind() == IK_LLVM_IR) {
663     BackendAction BA = static_cast<BackendAction>(Act);
664     CompilerInstance &CI = getCompilerInstance();
665     raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
666     if (BA != Backend_EmitNothing && !OS)
667       return;
668 
669     bool Invalid;
670     SourceManager &SM = CI.getSourceManager();
671     FileID FID = SM.getMainFileID();
672     llvm::MemoryBuffer *MainFile = SM.getBuffer(FID, &Invalid);
673     if (Invalid)
674       return;
675 
676     llvm::SMDiagnostic Err;
677     TheModule = parseIR(MainFile->getMemBufferRef(), Err, *VMContext);
678     if (!TheModule) {
679       // Translate from the diagnostic info to the SourceManager location if
680       // available.
681       // TODO: Unify this with ConvertBackendLocation()
682       SourceLocation Loc;
683       if (Err.getLineNo() > 0) {
684         assert(Err.getColumnNo() >= 0);
685         Loc = SM.translateFileLineCol(SM.getFileEntryForID(FID),
686                                       Err.getLineNo(), Err.getColumnNo() + 1);
687       }
688 
689       // Strip off a leading diagnostic code if there is one.
690       StringRef Msg = Err.getMessage();
691       if (Msg.startswith("error: "))
692         Msg = Msg.substr(7);
693 
694       unsigned DiagID =
695           CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
696 
697       CI.getDiagnostics().Report(Loc, DiagID) << Msg;
698       return;
699     }
700     const TargetOptions &TargetOpts = CI.getTargetOpts();
701     if (TheModule->getTargetTriple() != TargetOpts.Triple) {
702       unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
703           DiagnosticsEngine::Warning,
704           "overriding the module target triple with %0");
705 
706       CI.getDiagnostics().Report(SourceLocation(), DiagID) << TargetOpts.Triple;
707       TheModule->setTargetTriple(TargetOpts.Triple);
708     }
709 
710     EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(), TargetOpts,
711                       CI.getLangOpts(), CI.getTarget().getTargetDescription(),
712                       TheModule.get(), BA, OS);
713     return;
714   }
715 
716   // Otherwise follow the normal AST path.
717   this->ASTFrontendAction::ExecuteAction();
718 }
719 
720 //
721 
722 void EmitAssemblyAction::anchor() { }
723 EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
724   : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
725 
726 void EmitBCAction::anchor() { }
727 EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
728   : CodeGenAction(Backend_EmitBC, _VMContext) {}
729 
730 void EmitLLVMAction::anchor() { }
731 EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
732   : CodeGenAction(Backend_EmitLL, _VMContext) {}
733 
734 void EmitLLVMOnlyAction::anchor() { }
735 EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
736   : CodeGenAction(Backend_EmitNothing, _VMContext) {}
737 
738 void EmitCodeGenOnlyAction::anchor() { }
739 EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
740   : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
741 
742 void EmitObjAction::anchor() { }
743 EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
744   : CodeGenAction(Backend_EmitObj, _VMContext) {}
745