ASTUnit.cpp revision 194613 
1//===--- ASTUnit.cpp - ASTUnit utility ------------------------------------===//
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// ASTUnit Implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Frontend/ASTUnit.h"
15#include "clang/Frontend/PCHReader.h"
16#include "clang/Frontend/TextDiagnosticBuffer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclVisitor.h"
19#include "clang/AST/StmtVisitor.h"
20#include "clang/Lex/HeaderSearch.h"
21#include "clang/Lex/Preprocessor.h"
22#include "clang/Basic/TargetInfo.h"
23#include "clang/Basic/Diagnostic.h"
24#include "llvm/Support/Compiler.h"
25
26using namespace clang;
27
28ASTUnit::ASTUnit() { }
29ASTUnit::~ASTUnit() { }
30
31namespace {
32
33/// \brief Gathers information from PCHReader that will be used to initialize
34/// a Preprocessor.
35class VISIBILITY_HIDDEN PCHInfoCollector : public PCHReaderListener {
36  LangOptions &LangOpt;
37  HeaderSearch &HSI;
38  std::string &TargetTriple;
39  std::string &Predefines;
40  unsigned &Counter;
41
42  unsigned NumHeaderInfos;
43
44public:
45  PCHInfoCollector(LangOptions &LangOpt, HeaderSearch &HSI,
46                   std::string &TargetTriple, std::string &Predefines,
47                   unsigned &Counter)
48    : LangOpt(LangOpt), HSI(HSI), TargetTriple(TargetTriple),
49      Predefines(Predefines), Counter(Counter), NumHeaderInfos(0) {}
50
51  virtual bool ReadLanguageOptions(const LangOptions &LangOpts) {
52    LangOpt = LangOpts;
53    return false;
54  }
55
56  virtual bool ReadTargetTriple(const std::string &Triple) {
57    TargetTriple = Triple;
58    return false;
59  }
60
61  virtual bool ReadPredefinesBuffer(const char *PCHPredef,
62                                    unsigned PCHPredefLen,
63                                    FileID PCHBufferID,
64                                    std::string &SuggestedPredefines) {
65    Predefines = PCHPredef;
66    return false;
67  }
68
69  virtual void ReadHeaderFileInfo(const HeaderFileInfo &HFI) {
70    HSI.setHeaderFileInfoForUID(HFI, NumHeaderInfos++);
71  }
72
73  virtual void ReadCounter(unsigned Value) {
74    Counter = Value;
75  }
76};
77
78} // anonymous namespace
79
80
81ASTUnit *ASTUnit::LoadFromPCHFile(const std::string &Filename,
82                                  FileManager &FileMgr,
83                                  std::string *ErrMsg) {
84
85  llvm::OwningPtr<ASTUnit> AST(new ASTUnit());
86
87  AST->DiagClient.reset(new TextDiagnosticBuffer());
88  AST->Diags.reset(new Diagnostic(AST->DiagClient.get()));
89
90  AST->HeaderInfo.reset(new HeaderSearch(FileMgr));
91  AST->SourceMgr.reset(new SourceManager());
92
93  Diagnostic &Diags = *AST->Diags.get();
94  SourceManager &SourceMgr = *AST->SourceMgr.get();
95
96  // Gather Info for preprocessor construction later on.
97
98  LangOptions LangInfo;
99  HeaderSearch &HeaderInfo = *AST->HeaderInfo.get();
100  std::string TargetTriple;
101  std::string Predefines;
102  unsigned Counter;
103
104  llvm::OwningPtr<PCHReader> Reader;
105  llvm::OwningPtr<ExternalASTSource> Source;
106
107  Reader.reset(new PCHReader(SourceMgr, FileMgr, Diags));
108  Reader->setListener(new PCHInfoCollector(LangInfo, HeaderInfo, TargetTriple,
109                                           Predefines, Counter));
110
111  switch (Reader->ReadPCH(Filename)) {
112  case PCHReader::Success:
113    break;
114
115  case PCHReader::Failure:
116    // Unrecoverable failure: don't even try to process the input
117    // file.
118    if (ErrMsg)
119      *ErrMsg = "Could not load PCH file";
120    return NULL;
121
122  case PCHReader::IgnorePCH:
123    assert(0 && "Is there a validation that should not have happened ?");
124  }
125
126  // PCH loaded successfully. Now create the preprocessor.
127
128  // Get information about the target being compiled for.
129  AST->Target.reset(TargetInfo::CreateTargetInfo(TargetTriple));
130  AST->PP.reset(new Preprocessor(Diags, LangInfo, *AST->Target.get(),
131                                 SourceMgr, HeaderInfo));
132  Preprocessor &PP = *AST->PP.get();
133
134  PP.setPredefines(Predefines);
135  PP.setCounterValue(Counter);
136  Reader->setPreprocessor(PP);
137
138  // Create and initialize the ASTContext.
139
140  AST->Ctx.reset(new ASTContext(LangInfo,
141                                SourceMgr,
142                                *AST->Target.get(),
143                                PP.getIdentifierTable(),
144                                PP.getSelectorTable(),
145                                PP.getBuiltinInfo(),
146                                /* FreeMemory = */ true,
147                                /* size_reserve = */0));
148  ASTContext &Context = *AST->Ctx.get();
149
150  Reader->InitializeContext(Context);
151
152  // Attach the PCH reader to the AST context as an external AST
153  // source, so that declarations will be deserialized from the
154  // PCH file as needed.
155  Source.reset(Reader.take());
156  Context.setExternalSource(Source);
157
158  return AST.take();
159}
160