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//===--- CodeGenAction.cpp - LLVM Code Generation Frontend Action ---------===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "clang/CodeGen/CodeGenAction.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclGroup.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/BackendUtil.h"
#include "clang/CodeGen/ModuleBuilder.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Linker/Linker.h"
#include "llvm/Pass.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/Timer.h"
#include <memory>
using namespace clang;
using namespace llvm;
namespace clang {
class BackendConsumer : public ASTConsumer {
virtual void anchor();
DiagnosticsEngine &Diags;
BackendAction Action;
const CodeGenOptions &CodeGenOpts;
const TargetOptions &TargetOpts;
const LangOptions &LangOpts;
raw_ostream *AsmOutStream;
ASTContext *Context;
Timer LLVMIRGeneration;
std::unique_ptr<CodeGenerator> Gen;
std::unique_ptr<llvm::Module> TheModule, LinkModule;
BackendConsumer(BackendAction action, DiagnosticsEngine &_Diags,
const CodeGenOptions &compopts,
const TargetOptions &targetopts,
const LangOptions &langopts, bool TimePasses,
const std::string &infile, llvm::Module *LinkModule,
raw_ostream *OS, LLVMContext &C)
: Diags(_Diags), Action(action), CodeGenOpts(compopts),
TargetOpts(targetopts), LangOpts(langopts), AsmOutStream(OS),
Context(), LLVMIRGeneration("LLVM IR Generation Time"),
Gen(CreateLLVMCodeGen(Diags, infile, compopts, targetopts, C)),
LinkModule(LinkModule) {
llvm::TimePassesIsEnabled = TimePasses;
llvm::Module *takeModule() { return TheModule.release(); }
llvm::Module *takeLinkModule() { return LinkModule.release(); }
void HandleCXXStaticMemberVarInstantiation(VarDecl *VD) override {
void Initialize(ASTContext &Ctx) override {
Context = &Ctx;
if (llvm::TimePassesIsEnabled)
if (llvm::TimePassesIsEnabled)
bool HandleTopLevelDecl(DeclGroupRef D) override {
PrettyStackTraceDecl CrashInfo(*D.begin(), SourceLocation(),
"LLVM IR generation of declaration");
if (llvm::TimePassesIsEnabled)
if (llvm::TimePassesIsEnabled)
return true;
void HandleTranslationUnit(ASTContext &C) override {
PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
if (llvm::TimePassesIsEnabled)
if (llvm::TimePassesIsEnabled)
// Silently ignore if we weren't initialized for some reason.
if (!TheModule)
// Make sure IR generation is happy with the module. This is released by
// the module provider.
llvm::Module *M = Gen->ReleaseModule();
if (!M) {
// The module has been released by IR gen on failures, do not double
// free.
assert(TheModule.get() == M &&
"Unexpected module change during IR generation");
// Link LinkModule into this module if present, preserving its validity.
if (LinkModule) {
std::string ErrorMsg;
if (Linker::LinkModules(M, LinkModule.get(), Linker::PreserveSource,
&ErrorMsg)) {
<< LinkModule->getModuleIdentifier() << ErrorMsg;
// Install an inline asm handler so that diagnostics get printed through
// our diagnostics hooks.
LLVMContext &Ctx = TheModule->getContext();
LLVMContext::InlineAsmDiagHandlerTy OldHandler =
void *OldContext = Ctx.getInlineAsmDiagnosticContext();
Ctx.setInlineAsmDiagnosticHandler(InlineAsmDiagHandler, this);
LLVMContext::DiagnosticHandlerTy OldDiagnosticHandler =
void *OldDiagnosticContext = Ctx.getDiagnosticContext();
Ctx.setDiagnosticHandler(DiagnosticHandler, this);
EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
TheModule.get(), Action, AsmOutStream);
Ctx.setInlineAsmDiagnosticHandler(OldHandler, OldContext);
Ctx.setDiagnosticHandler(OldDiagnosticHandler, OldDiagnosticContext);
void HandleTagDeclDefinition(TagDecl *D) override {
PrettyStackTraceDecl CrashInfo(D, SourceLocation(),
"LLVM IR generation of declaration");
void HandleTagDeclRequiredDefinition(const TagDecl *D) override {
void CompleteTentativeDefinition(VarDecl *D) override {
void HandleVTable(CXXRecordDecl *RD, bool DefinitionRequired) override {
Gen->HandleVTable(RD, DefinitionRequired);
void HandleLinkerOptionPragma(llvm::StringRef Opts) override {
void HandleDetectMismatch(llvm::StringRef Name,
llvm::StringRef Value) override {
Gen->HandleDetectMismatch(Name, Value);
void HandleDependentLibrary(llvm::StringRef Opts) override {
static void InlineAsmDiagHandler(const llvm::SMDiagnostic &SM,void *Context,
unsigned LocCookie) {
SourceLocation Loc = SourceLocation::getFromRawEncoding(LocCookie);
((BackendConsumer*)Context)->InlineAsmDiagHandler2(SM, Loc);
static void DiagnosticHandler(const llvm::DiagnosticInfo &DI,
void *Context) {
((BackendConsumer *)Context)->DiagnosticHandlerImpl(DI);
void InlineAsmDiagHandler2(const llvm::SMDiagnostic &,
SourceLocation LocCookie);
void DiagnosticHandlerImpl(const llvm::DiagnosticInfo &DI);
/// \brief Specialized handler for InlineAsm diagnostic.
/// \return True if the diagnostic has been successfully reported, false
/// otherwise.
bool InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D);
/// \brief Specialized handler for StackSize diagnostic.
/// \return True if the diagnostic has been successfully reported, false
/// otherwise.
bool StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D);
void BackendConsumer::anchor() {}
/// ConvertBackendLocation - Convert a location in a temporary llvm::SourceMgr
/// buffer to be a valid FullSourceLoc.
static FullSourceLoc ConvertBackendLocation(const llvm::SMDiagnostic &D,
SourceManager &CSM) {
// Get both the clang and llvm source managers. The location is relative to
// a memory buffer that the LLVM Source Manager is handling, we need to add
// a copy to the Clang source manager.
const llvm::SourceMgr &LSM = *D.getSourceMgr();
// We need to copy the underlying LLVM memory buffer because llvm::SourceMgr
// already owns its one and clang::SourceManager wants to own its one.
const MemoryBuffer *LBuf =
// Create the copy and transfer ownership to clang::SourceManager.
llvm::MemoryBuffer *CBuf =
FileID FID = CSM.createFileIDForMemBuffer(CBuf);
// Translate the offset into the file.
unsigned Offset = D.getLoc().getPointer() - LBuf->getBufferStart();
SourceLocation NewLoc =
return FullSourceLoc(NewLoc, CSM);
/// InlineAsmDiagHandler2 - This function is invoked when the backend hits an
/// error parsing inline asm. The SMDiagnostic indicates the error relative to
/// the temporary memory buffer that the inline asm parser has set up.
void BackendConsumer::InlineAsmDiagHandler2(const llvm::SMDiagnostic &D,
SourceLocation LocCookie) {
// There are a couple of different kinds of errors we could get here. First,
// we re-format the SMDiagnostic in terms of a clang diagnostic.
// Strip "error: " off the start of the message string.
StringRef Message = D.getMessage();
if (Message.startswith("error: "))
Message = Message.substr(7);
// If the SMDiagnostic has an inline asm source location, translate it.
FullSourceLoc Loc;
if (D.getLoc() != SMLoc())
Loc = ConvertBackendLocation(D, Context->getSourceManager());
// If this problem has clang-level source location information, report the
// issue as being an error in the source with a note showing the instantiated
// code.
if (LocCookie.isValid()) {
Diags.Report(LocCookie, diag::err_fe_inline_asm).AddString(Message);
if (D.getLoc().isValid()) {
DiagnosticBuilder B = Diags.Report(Loc, diag::note_fe_inline_asm_here);
// Convert the SMDiagnostic ranges into SourceRange and attach them
// to the diagnostic.
for (unsigned i = 0, e = D.getRanges().size(); i != e; ++i) {
std::pair<unsigned, unsigned> Range = D.getRanges()[i];
unsigned Column = D.getColumnNo();
B << SourceRange(Loc.getLocWithOffset(Range.first - Column),
Loc.getLocWithOffset(Range.second - Column));
// Otherwise, report the backend error as occurring in the generated .s file.
// If Loc is invalid, we still need to report the error, it just gets no
// location info.
Diags.Report(Loc, diag::err_fe_inline_asm).AddString(Message);
#define ComputeDiagID(Severity, GroupName, DiagID) \
do { \
switch (Severity) { \
case llvm::DS_Error: \
DiagID = diag::err_fe_##GroupName; \
break; \
case llvm::DS_Warning: \
DiagID = diag::warn_fe_##GroupName; \
break; \
case llvm::DS_Remark: \
llvm_unreachable("'remark' severity not expected"); \
break; \
case llvm::DS_Note: \
DiagID = diag::note_fe_##GroupName; \
break; \
} \
} while (false)
#define ComputeDiagRemarkID(Severity, GroupName, DiagID) \
do { \
switch (Severity) { \
case llvm::DS_Error: \
DiagID = diag::err_fe_##GroupName; \
break; \
case llvm::DS_Warning: \
DiagID = diag::warn_fe_##GroupName; \
break; \
case llvm::DS_Remark: \
DiagID = diag::remark_fe_##GroupName; \
break; \
case llvm::DS_Note: \
DiagID = diag::note_fe_##GroupName; \
break; \
} \
} while (false)
BackendConsumer::InlineAsmDiagHandler(const llvm::DiagnosticInfoInlineAsm &D) {
unsigned DiagID;
ComputeDiagID(D.getSeverity(), inline_asm, DiagID);
std::string Message = D.getMsgStr().str();
// If this problem has clang-level source location information, report the
// issue as being a problem in the source with a note showing the instantiated
// code.
SourceLocation LocCookie =
if (LocCookie.isValid())
Diags.Report(LocCookie, DiagID).AddString(Message);
else {
// Otherwise, report the backend diagnostic as occurring in the generated
// .s file.
// If Loc is invalid, we still need to report the diagnostic, it just gets
// no location info.
FullSourceLoc Loc;
Diags.Report(Loc, DiagID).AddString(Message);
// We handled all the possible severities.
return true;
BackendConsumer::StackSizeDiagHandler(const llvm::DiagnosticInfoStackSize &D) {
if (D.getSeverity() != llvm::DS_Warning)
// For now, the only support we have for StackSize diagnostic is warning.
// We do not know how to format other severities.
return false;
// FIXME: We should demangle the function name.
// FIXME: Is there a way to get a location for that function?
FullSourceLoc Loc;
Diags.Report(Loc, diag::warn_fe_backend_frame_larger_than)
<< D.getStackSize() << D.getFunction().getName();
return true;
/// \brief This function is invoked when the backend needs
/// to report something to the user.
void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
unsigned DiagID = diag::err_fe_inline_asm;
llvm::DiagnosticSeverity Severity = DI.getSeverity();
// Get the diagnostic ID based.
switch (DI.getKind()) {
case llvm::DK_InlineAsm:
if (InlineAsmDiagHandler(cast<DiagnosticInfoInlineAsm>(DI)))
ComputeDiagID(Severity, inline_asm, DiagID);
case llvm::DK_StackSize:
if (StackSizeDiagHandler(cast<DiagnosticInfoStackSize>(DI)))
ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
// Plugin IDs are not bound to any value as they are set dynamically.
ComputeDiagRemarkID(Severity, backend_plugin, DiagID);
std::string MsgStorage;
raw_string_ostream Stream(MsgStorage);
DiagnosticPrinterRawOStream DP(Stream);
// Report the backend message using the usual diagnostic mechanism.
FullSourceLoc Loc;
Diags.Report(Loc, DiagID).AddString(MsgStorage);
#undef ComputeDiagID
CodeGenAction::CodeGenAction(unsigned _Act, LLVMContext *_VMContext)
: Act(_Act), LinkModule(0),
VMContext(_VMContext ? _VMContext : new LLVMContext),
OwnsVMContext(!_VMContext) {}
CodeGenAction::~CodeGenAction() {
if (OwnsVMContext)
delete VMContext;
bool CodeGenAction::hasIRSupport() const { return true; }
void CodeGenAction::EndSourceFileAction() {
// If the consumer creation failed, do nothing.
if (!getCompilerInstance().hasASTConsumer())
// If we were given a link module, release consumer's ownership of it.
if (LinkModule)
// Steal the module from the consumer.
llvm::Module *CodeGenAction::takeModule() { return TheModule.release(); }
llvm::LLVMContext *CodeGenAction::takeLLVMContext() {
OwnsVMContext = false;
return VMContext;
static raw_ostream *GetOutputStream(CompilerInstance &CI,
StringRef InFile,
BackendAction Action) {
switch (Action) {
case Backend_EmitAssembly:
return CI.createDefaultOutputFile(false, InFile, "s");
case Backend_EmitLL:
return CI.createDefaultOutputFile(false, InFile, "ll");
case Backend_EmitBC:
return CI.createDefaultOutputFile(true, InFile, "bc");
case Backend_EmitNothing:
return 0;
case Backend_EmitMCNull:
case Backend_EmitObj:
return CI.createDefaultOutputFile(true, InFile, "o");
llvm_unreachable("Invalid action!");
ASTConsumer *CodeGenAction::CreateASTConsumer(CompilerInstance &CI,
StringRef InFile) {
BackendAction BA = static_cast<BackendAction>(Act);
std::unique_ptr<raw_ostream> OS(GetOutputStream(CI, InFile, BA));
if (BA != Backend_EmitNothing && !OS)
return 0;
llvm::Module *LinkModuleToUse = LinkModule;
// If we were not given a link module, and the user requested that one be
// loaded from bitcode, do so now.
const std::string &LinkBCFile = CI.getCodeGenOpts().LinkBitcodeFile;
if (!LinkModuleToUse && !LinkBCFile.empty()) {
std::string ErrorStr;
llvm::MemoryBuffer *BCBuf =
CI.getFileManager().getBufferForFile(LinkBCFile, &ErrorStr);
if (!BCBuf) {
<< LinkBCFile << ErrorStr;
return 0;
ErrorOr<llvm::Module *> ModuleOrErr =
getLazyBitcodeModule(BCBuf, *VMContext);
if (error_code EC = ModuleOrErr.getError()) {
<< LinkBCFile << EC.message();
return 0;
LinkModuleToUse = ModuleOrErr.get();
BEConsumer = new BackendConsumer(BA, CI.getDiagnostics(), CI.getCodeGenOpts(),
CI.getTargetOpts(), CI.getLangOpts(),
CI.getFrontendOpts().ShowTimers, InFile,
LinkModuleToUse, OS.release(), *VMContext);
return BEConsumer;
void CodeGenAction::ExecuteAction() {
// If this is an IR file, we have to treat it specially.
if (getCurrentFileKind() == IK_LLVM_IR) {
BackendAction BA = static_cast<BackendAction>(Act);
CompilerInstance &CI = getCompilerInstance();
raw_ostream *OS = GetOutputStream(CI, getCurrentFile(), BA);
if (BA != Backend_EmitNothing && !OS)
bool Invalid;
SourceManager &SM = CI.getSourceManager();
const llvm::MemoryBuffer *MainFile = SM.getBuffer(SM.getMainFileID(),
if (Invalid)
// FIXME: This is stupid, IRReader shouldn't take ownership.
llvm::MemoryBuffer *MainFileCopy =
llvm::SMDiagnostic Err;
TheModule.reset(ParseIR(MainFileCopy, Err, *VMContext));
if (!TheModule) {
// Translate from the diagnostic info to the SourceManager location.
SourceLocation Loc = SM.translateFileLineCol(
SM.getFileEntryForID(SM.getMainFileID()), Err.getLineNo(),
Err.getColumnNo() + 1);
// Strip off a leading diagnostic code if there is one.
StringRef Msg = Err.getMessage();
if (Msg.startswith("error: "))
Msg = Msg.substr(7);
unsigned DiagID =
CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
CI.getDiagnostics().Report(Loc, DiagID) << Msg;
const TargetOptions &TargetOpts = CI.getTargetOpts();
if (TheModule->getTargetTriple() != TargetOpts.Triple) {
unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
"overriding the module target triple with %0");
CI.getDiagnostics().Report(SourceLocation(), DiagID) << TargetOpts.Triple;
EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(), TargetOpts,
CI.getLangOpts(), CI.getTarget().getTargetDescription(),
TheModule.get(), BA, OS);
// Otherwise follow the normal AST path.
void EmitAssemblyAction::anchor() { }
EmitAssemblyAction::EmitAssemblyAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitAssembly, _VMContext) {}
void EmitBCAction::anchor() { }
EmitBCAction::EmitBCAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitBC, _VMContext) {}
void EmitLLVMAction::anchor() { }
EmitLLVMAction::EmitLLVMAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitLL, _VMContext) {}
void EmitLLVMOnlyAction::anchor() { }
EmitLLVMOnlyAction::EmitLLVMOnlyAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitNothing, _VMContext) {}
void EmitCodeGenOnlyAction::anchor() { }
EmitCodeGenOnlyAction::EmitCodeGenOnlyAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitMCNull, _VMContext) {}
void EmitObjAction::anchor() { }
EmitObjAction::EmitObjAction(llvm::LLVMContext *_VMContext)
: CodeGenAction(Backend_EmitObj, _VMContext) {}