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