1 //===--- GeneratePCH.cpp - AST Consumer for PCH Generation ------*- C++ -*-===//
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 //  This file defines the CreatePCHGenerate function, which creates an
11 //  ASTConsumer that generates a PCH file.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/Frontend/ASTConsumers.h"
16 #include "clang/Serialization/ASTWriter.h"
17 #include "clang/Sema/SemaConsumer.h"
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/ASTConsumer.h"
20 #include "clang/Lex/Preprocessor.h"
21 #include "clang/Basic/FileManager.h"
22 #include "clang/Basic/FileSystemStatCache.h"
23 #include "llvm/Bitcode/BitstreamWriter.h"
24 #include "llvm/Support/raw_ostream.h"
25 #include <string>
26 
27 using namespace clang;
28 
29 PCHGenerator::PCHGenerator(const Preprocessor &PP,
30                            const std::string &OutputFile,
31                            bool Chaining,
32                            const char *isysroot,
33                            llvm::raw_ostream *OS)
34   : PP(PP), OutputFile(OutputFile), isysroot(isysroot), Out(OS), SemaPtr(0),
35     StatCalls(0), Stream(Buffer), Writer(Stream), Chaining(Chaining) {
36   // Install a stat() listener to keep track of all of the stat()
37   // calls.
38   StatCalls = new MemorizeStatCalls();
39   // If we have a chain, we want new stat calls only, so install the memorizer
40   // *after* the already installed ASTReader's stat cache.
41   PP.getFileManager().addStatCache(StatCalls,
42     /*AtBeginning=*/!Chaining);
43 }
44 
45 void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
46   if (PP.getDiagnostics().hasErrorOccurred())
47     return;
48 
49   // Set up the serialization listener.
50   Writer.SetSerializationListener(GetASTSerializationListener());
51 
52   // Emit the PCH file
53   assert(SemaPtr && "No Sema?");
54   Writer.WriteAST(*SemaPtr, StatCalls, OutputFile, isysroot);
55 
56   // Write the generated bitstream to "Out".
57   Out->write((char *)&Buffer.front(), Buffer.size());
58 
59   // Make sure it hits disk now.
60   Out->flush();
61 
62   // Free up some memory, in case the process is kept alive.
63   Buffer.clear();
64 }
65 
66 ASTMutationListener *PCHGenerator::GetASTMutationListener() {
67   if (Chaining)
68     return &Writer;
69   return 0;
70 }
71 
72 ASTSerializationListener *PCHGenerator::GetASTSerializationListener() {
73   return 0;
74 }
75 
76 ASTDeserializationListener *PCHGenerator::GetASTDeserializationListener() {
77   return &Writer;
78 }
79