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//===--- ObjectFilePCHContainerOperations.cpp -----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
#include "CGDebugInfo.h"
#include "CodeGenModule.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/Expr.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/BackendUtil.h"
#include "clang/Frontend/CodeGenOptions.h"
#include "clang/Serialization/ASTWriter.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Bitcode/BitstreamReader.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/TargetRegistry.h"
#include <memory>
using namespace clang;
#define DEBUG_TYPE "pchcontainer"
namespace {
class PCHContainerGenerator : public ASTConsumer {
DiagnosticsEngine &Diags;
const std::string MainFileName;
ASTContext *Ctx;
const HeaderSearchOptions &HeaderSearchOpts;
const PreprocessorOptions &PreprocessorOpts;
CodeGenOptions CodeGenOpts;
const TargetOptions TargetOpts;
const LangOptions LangOpts;
std::unique_ptr<llvm::LLVMContext> VMContext;
std::unique_ptr<llvm::Module> M;
std::unique_ptr<CodeGen::CodeGenModule> Builder;
raw_pwrite_stream *OS;
std::shared_ptr<PCHBuffer> Buffer;
public:
PCHContainerGenerator(DiagnosticsEngine &diags,
const HeaderSearchOptions &HSO,
const PreprocessorOptions &PPO, const TargetOptions &TO,
const LangOptions &LO, const std::string &MainFileName,
const std::string &OutputFileName,
raw_pwrite_stream *OS,
std::shared_ptr<PCHBuffer> Buffer)
: Diags(diags), HeaderSearchOpts(HSO), PreprocessorOpts(PPO),
TargetOpts(TO), LangOpts(LO), OS(OS), Buffer(Buffer) {
// The debug info output isn't affected by CodeModel and
// ThreadModel, but the backend expects them to be nonempty.
CodeGenOpts.CodeModel = "default";
CodeGenOpts.ThreadModel = "single";
CodeGenOpts.setDebugInfo(CodeGenOptions::FullDebugInfo);
CodeGenOpts.SplitDwarfFile = OutputFileName;
}
virtual ~PCHContainerGenerator() {}
void Initialize(ASTContext &Context) override {
Ctx = &Context;
VMContext.reset(new llvm::LLVMContext());
M.reset(new llvm::Module(MainFileName, *VMContext));
M->setDataLayout(Ctx->getTargetInfo().getTargetDescription());
Builder.reset(new CodeGen::CodeGenModule(*Ctx, HeaderSearchOpts,
PreprocessorOpts, CodeGenOpts, *M,
M->getDataLayout(), Diags));
}
/// Emit a container holding the serialized AST.
void HandleTranslationUnit(ASTContext &Ctx) override {
assert(M && VMContext && Builder);
// Delete these on function exit.
std::unique_ptr<llvm::LLVMContext> VMContext = std::move(this->VMContext);
std::unique_ptr<llvm::Module> M = std::move(this->M);
std::unique_ptr<CodeGen::CodeGenModule> Builder = std::move(this->Builder);
if (Diags.hasErrorOccurred())
return;
M->setTargetTriple(Ctx.getTargetInfo().getTriple().getTriple());
M->setDataLayout(Ctx.getTargetInfo().getTargetDescription());
// Finalize the Builder.
if (Builder)
Builder->Release();
// Ensure the target exists.
std::string Error;
auto Triple = Ctx.getTargetInfo().getTriple();
if (!llvm::TargetRegistry::lookupTarget(Triple.getTriple(), Error))
llvm::report_fatal_error(Error);
// Emit the serialized Clang AST into its own section.
assert(Buffer->IsComplete && "serialization did not complete");
auto &SerializedAST = Buffer->Data;
auto Size = SerializedAST.size();
auto Int8Ty = llvm::Type::getInt8Ty(*VMContext);
auto *Ty = llvm::ArrayType::get(Int8Ty, Size);
auto *Data = llvm::ConstantDataArray::getString(
*VMContext, StringRef(SerializedAST.data(), Size),
/*AddNull=*/false);
auto *ASTSym = new llvm::GlobalVariable(
*M, Ty, /*constant*/ true, llvm::GlobalVariable::InternalLinkage, Data,
"__clang_ast");
// The on-disk hashtable needs to be aligned.
ASTSym->setAlignment(8);
// Mach-O also needs a segment name.
if (Triple.isOSBinFormatMachO())
ASTSym->setSection("__CLANG,__clangast");
// COFF has an eight character length limit.
else if (Triple.isOSBinFormatCOFF())
ASTSym->setSection("clangast");
else
ASTSym->setSection("__clangast");
DEBUG({
// Print the IR for the PCH container to the debug output.
llvm::SmallString<0> Buffer;
llvm::raw_svector_ostream OS(Buffer);
clang::EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
Ctx.getTargetInfo().getTargetDescription(),
M.get(), BackendAction::Backend_EmitLL, &OS);
OS.flush();
llvm::dbgs() << Buffer;
});
// Use the LLVM backend to emit the pch container.
clang::EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
Ctx.getTargetInfo().getTargetDescription(),
M.get(), BackendAction::Backend_EmitObj, OS);
// Make sure the pch container hits disk.
OS->flush();
// Free the memory for the temporary buffer.
llvm::SmallVector<char, 0> Empty;
SerializedAST = std::move(Empty);
}
};
} // namespace
std::unique_ptr<ASTConsumer>
ObjectFilePCHContainerWriter::CreatePCHContainerGenerator(
DiagnosticsEngine &Diags, const HeaderSearchOptions &HSO,
const PreprocessorOptions &PPO, const TargetOptions &TO,
const LangOptions &LO, const std::string &MainFileName,
const std::string &OutputFileName, llvm::raw_pwrite_stream *OS,
std::shared_ptr<PCHBuffer> Buffer) const {
return llvm::make_unique<PCHContainerGenerator>(
Diags, HSO, PPO, TO, LO, MainFileName, OutputFileName, OS, Buffer);
}
void ObjectFilePCHContainerReader::ExtractPCH(
llvm::MemoryBufferRef Buffer, llvm::BitstreamReader &StreamFile) const {
if (auto OF = llvm::object::ObjectFile::createObjectFile(Buffer)) {
auto *Obj = OF.get().get();
bool IsCOFF = isa<llvm::object::COFFObjectFile>(Obj);
// Find the clang AST section in the container.
for (auto &Section : OF->get()->sections()) {
StringRef Name;
Section.getName(Name);
if ((!IsCOFF && Name == "__clangast") ||
( IsCOFF && Name == "clangast")) {
StringRef Buf;
Section.getContents(Buf);
StreamFile.init((const unsigned char *)Buf.begin(),
(const unsigned char *)Buf.end());
return;
}
}
}
// As a fallback, treat the buffer as a raw AST.
StreamFile.init((const unsigned char *)Buffer.getBufferStart(),
(const unsigned char *)Buffer.getBufferEnd());
return;
}
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