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      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 "clang/CodeGen/CodeGenAction.h"
     11 #include "clang/AST/ASTConsumer.h"
     12 #include "clang/AST/ASTContext.h"
     13 #include "clang/AST/DeclGroup.h"
     14 #include "clang/Basic/FileManager.h"
     15 #include "clang/Basic/SourceManager.h"
     16 #include "clang/Basic/TargetInfo.h"
     17 #include "clang/CodeGen/BackendUtil.h"
     18 #include "clang/CodeGen/ModuleBuilder.h"
     19 #include "clang/Frontend/CompilerInstance.h"
     20 #include "clang/Frontend/FrontendDiagnostic.h"
     21 #include "llvm/ADT/OwningPtr.h"
     22 #include "llvm/ADT/SmallString.h"
     23 #include "llvm/Bitcode/ReaderWriter.h"
     24 #include "llvm/IR/LLVMContext.h"
     25 #include "llvm/IR/Module.h"
     26 #include "llvm/Linker.h"
     27 #include "llvm/Pass.h"
     28 #include "llvm/Support/IRReader.h"
     29 #include "llvm/Support/MemoryBuffer.h"
     30 #include "llvm/Support/SourceMgr.h"
     31 #include "llvm/Support/Timer.h"
     32 using namespace clang;
     33 using namespace llvm;
     34 
     35 namespace clang {
     36   class BackendConsumer : public ASTConsumer {
     37     virtual void anchor();
     38     DiagnosticsEngine &Diags;
     39     BackendAction Action;
     40     const CodeGenOptions &CodeGenOpts;
     41     const TargetOptions &TargetOpts;
     42     const LangOptions &LangOpts;
     43     raw_ostream *AsmOutStream;
     44     ASTContext *Context;
     45 
     46     Timer LLVMIRGeneration;
     47 
     48     OwningPtr<CodeGenerator> Gen;
     49 
     50     OwningPtr<llvm::Module> TheModule, LinkModule;
     51 
     52   public:
     53     BackendConsumer(BackendAction action, DiagnosticsEngine &_Diags,
     54                     const CodeGenOptions &compopts,
     55                     const TargetOptions &targetopts,
     56                     const LangOptions &langopts,
     57                     bool TimePasses,
     58                     const std::string &infile,
     59                     llvm::Module *LinkModule,
     60                     raw_ostream *OS,
     61                     LLVMContext &C) :
     62       Diags(_Diags),
     63       Action(action),
     64       CodeGenOpts(compopts),
     65       TargetOpts(targetopts),
     66       LangOpts(langopts),
     67       AsmOutStream(OS),
     68       Context(),
     69       LLVMIRGeneration("LLVM IR Generation Time"),
     70       Gen(CreateLLVMCodeGen(Diags, infile, compopts, targetopts, C)),
     71       LinkModule(LinkModule)
     72     {
     73       llvm::TimePassesIsEnabled = TimePasses;
     74     }
     75 
     76     llvm::Module *takeModule() { return TheModule.take(); }
     77     llvm::Module *takeLinkModule() { return LinkModule.take(); }
     78 
     79     virtual void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) {
     80       Gen->HandleCXXStaticMemberVarInstantiation(VD);
     81     }
     82 
     83     virtual void Initialize(ASTContext &Ctx) {
     84       Context = &Ctx;
     85 
     86       if (llvm::TimePassesIsEnabled)
     87         LLVMIRGeneration.startTimer();
     88 
     89       Gen->Initialize(Ctx);
     90 
     91       TheModule.reset(Gen->GetModule());
     92 
     93       if (llvm::TimePassesIsEnabled)
     94         LLVMIRGeneration.stopTimer();
     95     }
     96 
     97     virtual bool HandleTopLevelDecl(DeclGroupRef D) {
     98       PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
     99                                      Context->getSourceManager(),
    100                                      "LLVM IR generation of declaration");
    101 
    102       if (llvm::TimePassesIsEnabled)
    103         LLVMIRGeneration.startTimer();
    104 
    105       Gen->HandleTopLevelDecl(D);
    106 
    107       if (llvm::TimePassesIsEnabled)
    108         LLVMIRGeneration.stopTimer();
    109 
    110       return true;
    111     }
    112 
    113     virtual void HandleTranslationUnit(ASTContext &C) {
    114       {
    115         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
    116         if (llvm::TimePassesIsEnabled)
    117           LLVMIRGeneration.startTimer();
    118 
    119         Gen->HandleTranslationUnit(C);
    120 
    121         if (llvm::TimePassesIsEnabled)
    122           LLVMIRGeneration.stopTimer();
    123       }
    124 
    125       // Silently ignore if we weren't initialized for some reason.
    126       if (!TheModule)
    127         return;
    128 
    129       // Make sure IR generation is happy with the module. This is released by
    130       // the module provider.
    131       llvm::Module *M = Gen->ReleaseModule();
    132       if (!M) {
    133         // The module has been released by IR gen on failures, do not double
    134         // free.
    135         TheModule.take();
    136         return;
    137       }
    138 
    139       assert(TheModule.get() == M &&
    140              "Unexpected module change during IR generation");
    141 
    142       // Link LinkModule into this module if present, preserving its validity.
    143       if (LinkModule) {
    144         std::string ErrorMsg;
    145         if (Linker::LinkModules(M, LinkModule.get(), Linker::PreserveSource,
    146                                 &ErrorMsg)) {
    147           Diags.Report(diag::err_fe_cannot_link_module)
    148             << LinkModule->getModuleIdentifier() << ErrorMsg;
    149           return;
    150         }
    151       }
    152 
    153       // Install an inline asm handler so that diagnostics get printed through
    154       // our diagnostics hooks.
    155       LLVMContext &Ctx = TheModule->getContext();
    156       LLVMContext::InlineAsmDiagHandlerTy OldHandler =
    157         Ctx.getInlineAsmDiagnosticHandler();
    158       void *OldContext = Ctx.getInlineAsmDiagnosticContext();
    159       Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
    160 
    161       EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
    162                         TheModule.get(), Action, AsmOutStream);
    163 
    164       Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
    165     }
    166 
    167     virtual void HandleTagDeclDefinition(TagDecl *D) {
    168       PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
    169                                      Context->getSourceManager(),
    170                                      "LLVM IR generation of declaration");
    171       Gen->HandleTagDeclDefinition(D);
    172     }
    173 
    174     virtual void CompleteTentativeDefinition(VarDecl *D) {
    175       Gen->CompleteTentativeDefinition(D);
    176     }
    177 
    178     virtual void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) {
    179       Gen->HandleVTable(RD, DefinitionRequired);
    180     }
    181 
    182     static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
    183                                      unsigned LocCookie) {
    184       SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
    185       ((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
    186     }
    187 
    188     void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
    189                                SourceLocation LocCookie);
    190   };
    191 
    192   void BackendConsumer::anchor() {}
    193 }
    194 
    195 /// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
    196 /// buffer to be a valid FullSourceLoc.
    197 static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
    198                                             SourceManager &CSM) {
    199   // Get both the clang and llvm source managers.  The location is relative to
    200   // a memory buffer that the LLVM Source Manager is handling, we need to add
    201   // a copy to the Clang source manager.
    202   const llvm::SourceMgr &LSM = *D.getSourceMgr();
    203 
    204   // We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
    205   // already owns its one and clang::SourceManager wants to own its one.
    206   const MemoryBuffer *LBuf =
    207   LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
    208 
    209   // Create the copy and transfer ownership to clang::SourceManager.
    210   llvm::MemoryBuffer *CBuf =
    211   llvm::MemoryBuffer::getMemBufferCopy(LBuf->getBuffer(),
    212                                        LBuf->getBufferIdentifier());
    213   FileID FID = CSM.createFileIDForMemBuffer(CBuf);
    214 
    215   // Translate the offset into the file.
    216   unsigned Offset = D.getLoc().getPointer()  - LBuf->getBufferStart();
    217   SourceLocation NewLoc =
    218   CSM.getLocForStartOfFile(FID).getLocWithOffset(Offset);
    219   return FullSourceLoc(NewLoc, CSM);
    220 }
    221 
    222 
    223 /// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
    224 /// error parsing inline asm.  The SMDiagnostic indicates the error relative to
    225 /// the temporary memory buffer that the inline asm parser has set up.
    226 void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
    227                                             SourceLocation LocCookie) {
    228   // There are a couple of different kinds of errors we could get here.  First,
    229   // we re-format the SMDiagnostic in terms of a clang diagnostic.
    230 
    231   // Strip "error: " off the start of the message string.
    232   StringRef Message = D.getMessage();
    233   if (Message.startswith("error: "))
    234     Message = Message.substr(7);
    235 
    236   // If the SMDiagnostic has an inline asm source location, translate it.
    237   FullSourceLoc Loc;
    238   if (D.getLoc() != SMLoc())
    239     Loc = ConvertBackendLocation(D, Context->getSourceManager());
    240 
    241 
    242   // If this problem has clang-level source location information, report the
    243   // issue as being an error in the source with a note showing the instantiated
    244   // code.
    245   if (LocCookie.isValid()) {
    246     Diags.Report(LocCookie, diag::err_fe_inline_asm).AddString(Message);
    247 
    248     if (D.getLoc().isValid()) {
    249       DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
    250       // Convert the SMDiagnostic ranges into SourceRange and attach them
    251       // to the diagnostic.
    252       for (unsigned i = 0, e = D.getRanges().size(); i != e; ++i) {
    253         std::pair<unsigned, unsigned> Range = D.getRanges()[i];
    254         unsigned Column = D.getColumnNo();
    255         B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
    256                          Loc.getLocWithOffset(Range.second - Column));
    257       }
    258     }
    259     return;
    260   }
    261 
    262   // Otherwise, report the backend error as occurring in the generated .s file.
    263   // If Loc is invalid, we still need to report the error, it just gets no
    264   // location info.
    265   Diags.Report(Loc, diag::err_fe_inline_asm).AddString(Message);
    266 }
    267 
    268 //
    269 
    270 CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
    271   : Act(_Act), LinkModule(0),
    272     VMContext(_VMContext ? _VMContext : new LLVMContext),
    273     OwnsVMContext(!_VMContext) {}
    274 
    275 CodeGenAction::~CodeGenAction() {
    276   TheModule.reset();
    277   if (OwnsVMContext)
    278     delete VMContext;
    279 }
    280 
    281 bool CodeGenAction::hasIRSupport() const { return true; }
    282 
    283 void CodeGenAction::EndSourceFileAction() {
    284   // If the consumer creation failed, do nothing.
    285   if (!getCompilerInstance().hasASTConsumer())
    286     return;
    287 
    288   // If we were given a link module, release consumer's ownership of it.
    289   if (LinkModule)
    290     BEConsumer->takeLinkModule();
    291 
    292   // Steal the module from the consumer.
    293   TheModule.reset(BEConsumer->takeModule());
    294 }
    295 
    296 llvm::Module *CodeGenAction::takeModule() {
    297   return TheModule.take();
    298 }
    299 
    300 llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
    301   OwnsVMContext = false;
    302   return VMContext;
    303 }
    304 
    305 static raw_ostream *GetOutputStream(CompilerInstance &CI,
    306                                     StringRef InFile,
    307                                     BackendAction Action) {
    308   switch (Action) {
    309   case Backend_EmitAssembly:
    310     return CI.createDefaultOutputFile(false, InFile, "s");
    311   case Backend_EmitLL:
    312     return CI.createDefaultOutputFile(false, InFile, "ll");
    313   case Backend_EmitBC:
    314     return CI.createDefaultOutputFile(true, InFile, "bc");
    315   case Backend_EmitNothing:
    316     return 0;
    317   case Backend_EmitMCNull:
    318   case Backend_EmitObj:
    319     return CI.createDefaultOutputFile(true, InFile, "o");
    320   }
    321 
    322   llvm_unreachable("Invalid action!");
    323 }
    324 
    325 ASTConsumer *CodeGenAction::CreateASTConsumer(CompilerInstance &CI,
    326                                               StringRef InFile) {
    327   BackendAction BA = static_cast<BackendAction>(Act);
    328   OwningPtr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
    329   if (BA != Backend_EmitNothing && !OS)
    330     return 0;
    331 
    332   llvm::Module *LinkModuleToUse = LinkModule;
    333 
    334   // If we were not given a link module, and the user requested that one be
    335   // loaded from bitcode, do so now.
    336   const std::string &LinkBCFile = CI.getCodeGenOpts().LinkBitcodeFile;
    337   if (!LinkModuleToUse && !LinkBCFile.empty()) {
    338     std::string ErrorStr;
    339 
    340     llvm::MemoryBuffer *BCBuf =
    341       CI.getFileManager().getBufferForFile(LinkBCFile, &ErrorStr);
    342     if (!BCBuf) {
    343       CI.getDiagnostics().Report(diag::err_cannot_open_file)
    344         << LinkBCFile << ErrorStr;
    345       return 0;
    346     }
    347 
    348     LinkModuleToUse = getLazyBitcodeModule(BCBuf, *VMContext, &ErrorStr);
    349     if (!LinkModuleToUse) {
    350       CI.getDiagnostics().Report(diag::err_cannot_open_file)
    351         << LinkBCFile << ErrorStr;
    352       return 0;
    353     }
    354   }
    355 
    356   BEConsumer =
    357       new BackendConsumer(BA, CI.getDiagnostics(),
    358                           CI.getCodeGenOpts(), CI.getTargetOpts(),
    359                           CI.getLangOpts(),
    360                           CI.getFrontendOpts().ShowTimers, InFile,
    361                           LinkModuleToUse, OS.take(), *VMContext);
    362   return BEConsumer;
    363 }
    364 
    365 void CodeGenAction::ExecuteAction() {
    366   // If this is an IR file, we have to treat it specially.
    367   if (getCurrentFileKind() == IK_LLVM_IR) {
    368     BackendAction BA = static_cast<BackendAction>(Act);
    369     CompilerInstance &CI = getCompilerInstance();
    370     raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
    371     if (BA != Backend_EmitNothing && !OS)
    372       return;
    373 
    374     bool Invalid;
    375     SourceManager &SM = CI.getSourceManager();
    376     const llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(),
    377                                                       &Invalid);
    378     if (Invalid)
    379       return;
    380 
    381     // FIXME: This is stupid, IRReader shouldn't take ownership.
    382     llvm::MemoryBuffer *MainFileCopy =
    383       llvm::MemoryBuffer::getMemBufferCopy(MainFile->getBuffer(),
    384                                            getCurrentFile());
    385 
    386     llvm::SMDiagnostic Err;
    387     TheModule.reset(ParseIR(MainFileCopy, Err, *VMContext));
    388     if (!TheModule) {
    389       // Translate from the diagnostic info to the SourceManager location.
    390       SourceLocation Loc = SM.translateFileLineCol(
    391         SM.getFileEntryForID(SM.getMainFileID()), Err.getLineNo(),
    392         Err.getColumnNo() + 1);
    393 
    394       // Get a custom diagnostic for the error. We strip off a leading
    395       // diagnostic code if there is one.
    396       StringRef Msg = Err.getMessage();
    397       if (Msg.startswith("error: "))
    398         Msg = Msg.substr(7);
    399 
    400       // Escape '%', which is interpreted as a format character.
    401       SmallString<128> EscapedMessage;
    402       for (unsigned i = 0, e = Msg.size(); i != e; ++i) {
    403         if (Msg[i] == '%')
    404           EscapedMessage += '%';
    405         EscapedMessage += Msg[i];
    406       }
    407 
    408       unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
    409           DiagnosticsEngine::Error, EscapedMessage);
    410 
    411       CI.getDiagnostics().Report(Loc, DiagID);
    412       return;
    413     }
    414 
    415     EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(),
    416                       CI.getTargetOpts(), CI.getLangOpts(),
    417                       TheModule.get(),
    418                       BA, OS);
    419     return;
    420   }
    421 
    422   // Otherwise follow the normal AST path.
    423   this->ASTFrontendAction::ExecuteAction();
    424 }
    425 
    426 //
    427 
    428 void EmitAssemblyAction::anchor() { }
    429 EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
    430   : CodeGenAction(Backend_EmitAssembly, _VMContext) {}
    431 
    432 void EmitBCAction::anchor() { }
    433 EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
    434   : CodeGenAction(Backend_EmitBC, _VMContext) {}
    435 
    436 void EmitLLVMAction::anchor() { }
    437 EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
    438   : CodeGenAction(Backend_EmitLL, _VMContext) {}
    439 
    440 void EmitLLVMOnlyAction::anchor() { }
    441 EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
    442   : CodeGenAction(Backend_EmitNothing, _VMContext) {}
    443 
    444 void EmitCodeGenOnlyAction::anchor() { }
    445 EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
    446   : CodeGenAction(Backend_EmitMCNull, _VMContext) {}
    447 
    448 void EmitObjAction::anchor() { }
    449 EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
    450   : CodeGenAction(Backend_EmitObj, _VMContext) {}
    451