llvm-project/clang/lib/Frontend/GeneratePCH.cpp

87 lines
2.8 KiB
C++

//===--- GeneratePCH.cpp - AST Consumer for PCH Generation ------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the CreatePCHGenerate function, which creates an
// ASTConsume that generates a PCH file.
//
//===----------------------------------------------------------------------===//
#include "clang/Frontend/ASTConsumers.h"
#include "clang/Frontend/PCHWriter.h"
#include "clang/Sema/SemaConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/FileManager.h"
#include "llvm/Bitcode/BitstreamWriter.h"
#include "llvm/Support/raw_ostream.h"
#include <string>
using namespace clang;
namespace {
class PCHGenerator : public SemaConsumer {
const Preprocessor &PP;
const char *isysroot;
llvm::raw_ostream *Out;
Sema *SemaPtr;
MemorizeStatCalls *StatCalls; // owned by the FileManager
std::vector<unsigned char> Buffer;
llvm::BitstreamWriter Stream;
PCHWriter Writer;
public:
PCHGenerator(const Preprocessor &PP, PCHReader *Chain,
const char *isysroot, llvm::raw_ostream *Out);
virtual void InitializeSema(Sema &S) { SemaPtr = &S; }
virtual void HandleTranslationUnit(ASTContext &Ctx);
};
}
PCHGenerator::PCHGenerator(const Preprocessor &PP,
PCHReader *Chain,
const char *isysroot,
llvm::raw_ostream *OS)
: PP(PP), isysroot(isysroot), Out(OS), SemaPtr(0), StatCalls(0),
Stream(Buffer), Writer(Stream, Chain) {
// Install a stat() listener to keep track of all of the stat()
// calls.
StatCalls = new MemorizeStatCalls;
// If we have a chain, we want new stat calls only, so install the memorizer
// *after* the already installed PCHReader's stat cache.
PP.getFileManager().addStatCache(StatCalls,
/*AtBeginning=*/!Chain);
}
void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
if (PP.getDiagnostics().hasErrorOccurred())
return;
// Emit the PCH file
assert(SemaPtr && "No Sema?");
Writer.WritePCH(*SemaPtr, StatCalls, isysroot);
// Write the generated bitstream to "Out".
Out->write((char *)&Buffer.front(), Buffer.size());
// Make sure it hits disk now.
Out->flush();
// Free up some memory, in case the process is kept alive.
Buffer.clear();
}
ASTConsumer *clang::CreatePCHGenerator(const Preprocessor &PP,
llvm::raw_ostream *OS,
PCHReader *Chain,
const char *isysroot) {
return new PCHGenerator(PP, Chain, isysroot, OS);
}