1//===- ChainedIncludesSource.cpp - Chained PCHs in Memory -------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//  This file defines the ChainedIncludesSource class, which converts headers
10//  to chained PCHs in memory, mainly used for testing.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Basic/Builtins.h"
15#include "clang/Basic/TargetInfo.h"
16#include "clang/Frontend/ASTUnit.h"
17#include "clang/Frontend/CompilerInstance.h"
18#include "clang/Frontend/TextDiagnosticPrinter.h"
19#include "clang/Lex/Preprocessor.h"
20#include "clang/Lex/PreprocessorOptions.h"
21#include "clang/Parse/ParseAST.h"
22#include "clang/Sema/MultiplexExternalSemaSource.h"
23#include "clang/Serialization/ASTReader.h"
24#include "clang/Serialization/ASTWriter.h"
25#include "llvm/Support/MemoryBuffer.h"
26
27using namespace clang;
28
29namespace {
30class ChainedIncludesSourceImpl : public ExternalSemaSource {
31public:
32  ChainedIncludesSourceImpl(std::vector<std::unique_ptr<CompilerInstance>> CIs)
33      : CIs(std::move(CIs)) {}
34
35protected:
36  //===----------------------------------------------------------------------===//
37  // ExternalASTSource interface.
38  //===----------------------------------------------------------------------===//
39
40  /// Return the amount of memory used by memory buffers, breaking down
41  /// by heap-backed versus mmap'ed memory.
42  void getMemoryBufferSizes(MemoryBufferSizes &sizes) const override {
43    for (unsigned i = 0, e = CIs.size(); i != e; ++i) {
44      if (const ExternalASTSource *eSrc =
45          CIs[i]->getASTContext().getExternalSource()) {
46        eSrc->getMemoryBufferSizes(sizes);
47      }
48    }
49  }
50
51private:
52  std::vector<std::unique_ptr<CompilerInstance>> CIs;
53};
54
55/// Members of ChainedIncludesSource, factored out so we can initialize
56/// them before we initialize the ExternalSemaSource base class.
57struct ChainedIncludesSourceMembers {
58  ChainedIncludesSourceMembers(
59      std::vector<std::unique_ptr<CompilerInstance>> CIs,
60      IntrusiveRefCntPtr<ExternalSemaSource> FinalReader)
61      : Impl(std::move(CIs)), FinalReader(std::move(FinalReader)) {}
62  ChainedIncludesSourceImpl Impl;
63  IntrusiveRefCntPtr<ExternalSemaSource> FinalReader;
64};
65
66/// Use MultiplexExternalSemaSource to dispatch all ExternalSemaSource
67/// calls to the final reader.
68class ChainedIncludesSource
69    : private ChainedIncludesSourceMembers,
70      public MultiplexExternalSemaSource {
71public:
72  ChainedIncludesSource(std::vector<std::unique_ptr<CompilerInstance>> CIs,
73                        IntrusiveRefCntPtr<ExternalSemaSource> FinalReader)
74      : ChainedIncludesSourceMembers(std::move(CIs), std::move(FinalReader)),
75        MultiplexExternalSemaSource(Impl, *this->FinalReader) {}
76};
77}
78
79static ASTReader *
80createASTReader(CompilerInstance &CI, StringRef pchFile,
81                SmallVectorImpl<std::unique_ptr<llvm::MemoryBuffer>> &MemBufs,
82                SmallVectorImpl<std::string> &bufNames,
83                ASTDeserializationListener *deserialListener = nullptr) {
84  Preprocessor &PP = CI.getPreprocessor();
85  std::unique_ptr<ASTReader> Reader;
86  Reader.reset(new ASTReader(PP, CI.getModuleCache(), &CI.getASTContext(),
87                             CI.getPCHContainerReader(),
88                             /*Extensions=*/{},
89                             /*isysroot=*/"", /*DisableValidation=*/true));
90  for (unsigned ti = 0; ti < bufNames.size(); ++ti) {
91    StringRef sr(bufNames[ti]);
92    Reader->addInMemoryBuffer(sr, std::move(MemBufs[ti]));
93  }
94  Reader->setDeserializationListener(deserialListener);
95  switch (Reader->ReadAST(pchFile, serialization::MK_PCH, SourceLocation(),
96                          ASTReader::ARR_None)) {
97  case ASTReader::Success:
98    // Set the predefines buffer as suggested by the PCH reader.
99    PP.setPredefines(Reader->getSuggestedPredefines());
100    return Reader.release();
101
102  case ASTReader::Failure:
103  case ASTReader::Missing:
104  case ASTReader::OutOfDate:
105  case ASTReader::VersionMismatch:
106  case ASTReader::ConfigurationMismatch:
107  case ASTReader::HadErrors:
108    break;
109  }
110  return nullptr;
111}
112
113IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
114    CompilerInstance &CI, IntrusiveRefCntPtr<ExternalSemaSource> &Reader) {
115
116  std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
117  assert(!includes.empty() && "No '-chain-include' in options!");
118
119  std::vector<std::unique_ptr<CompilerInstance>> CIs;
120  InputKind IK = CI.getFrontendOpts().Inputs[0].getKind();
121
122  SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> SerialBufs;
123  SmallVector<std::string, 4> serialBufNames;
124
125  for (unsigned i = 0, e = includes.size(); i != e; ++i) {
126    bool firstInclude = (i == 0);
127    std::unique_ptr<CompilerInvocation> CInvok;
128    CInvok.reset(new CompilerInvocation(CI.getInvocation()));
129
130    CInvok->getPreprocessorOpts().ChainedIncludes.clear();
131    CInvok->getPreprocessorOpts().ImplicitPCHInclude.clear();
132    CInvok->getPreprocessorOpts().DisablePCHValidation = true;
133    CInvok->getPreprocessorOpts().Includes.clear();
134    CInvok->getPreprocessorOpts().MacroIncludes.clear();
135    CInvok->getPreprocessorOpts().Macros.clear();
136
137    CInvok->getFrontendOpts().Inputs.clear();
138    FrontendInputFile InputFile(includes[i], IK);
139    CInvok->getFrontendOpts().Inputs.push_back(InputFile);
140
141    TextDiagnosticPrinter *DiagClient =
142      new TextDiagnosticPrinter(llvm::errs(), new DiagnosticOptions());
143    IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
144    IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
145        new DiagnosticsEngine(DiagID, &CI.getDiagnosticOpts(), DiagClient));
146
147    std::unique_ptr<CompilerInstance> Clang(
148        new CompilerInstance(CI.getPCHContainerOperations()));
149    Clang->setInvocation(std::move(CInvok));
150    Clang->setDiagnostics(Diags.get());
151    Clang->setTarget(TargetInfo::CreateTargetInfo(
152        Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
153    Clang->createFileManager();
154    Clang->createSourceManager(Clang->getFileManager());
155    Clang->createPreprocessor(TU_Prefix);
156    Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
157                                                 &Clang->getPreprocessor());
158    Clang->createASTContext();
159
160    auto Buffer = std::make_shared<PCHBuffer>();
161    ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions;
162    auto consumer = std::make_unique<PCHGenerator>(
163        Clang->getPreprocessor(), Clang->getModuleCache(), "-", /*isysroot=*/"",
164        Buffer, Extensions, /*AllowASTWithErrors=*/true);
165    Clang->getASTContext().setASTMutationListener(
166                                            consumer->GetASTMutationListener());
167    Clang->setASTConsumer(std::move(consumer));
168    Clang->createSema(TU_Prefix, nullptr);
169
170    if (firstInclude) {
171      Preprocessor &PP = Clang->getPreprocessor();
172      PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
173                                             PP.getLangOpts());
174    } else {
175      assert(!SerialBufs.empty());
176      SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> Bufs;
177      // TODO: Pass through the existing MemoryBuffer instances instead of
178      // allocating new ones.
179      for (auto &SB : SerialBufs)
180        Bufs.push_back(llvm::MemoryBuffer::getMemBuffer(SB->getBuffer()));
181      std::string pchName = includes[i-1];
182      llvm::raw_string_ostream os(pchName);
183      os << ".pch" << i-1;
184      serialBufNames.push_back(os.str());
185
186      IntrusiveRefCntPtr<ASTReader> Reader;
187      Reader = createASTReader(
188          *Clang, pchName, Bufs, serialBufNames,
189          Clang->getASTConsumer().GetASTDeserializationListener());
190      if (!Reader)
191        return nullptr;
192      Clang->setModuleManager(Reader);
193      Clang->getASTContext().setExternalSource(Reader);
194    }
195
196    if (!Clang->InitializeSourceManager(InputFile))
197      return nullptr;
198
199    ParseAST(Clang->getSema());
200    Clang->getDiagnosticClient().EndSourceFile();
201    assert(Buffer->IsComplete && "serialization did not complete");
202    auto &serialAST = Buffer->Data;
203    SerialBufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
204        StringRef(serialAST.data(), serialAST.size())));
205    serialAST.clear();
206    CIs.push_back(std::move(Clang));
207  }
208
209  assert(!SerialBufs.empty());
210  std::string pchName = includes.back() + ".pch-final";
211  serialBufNames.push_back(pchName);
212  Reader = createASTReader(CI, pchName, SerialBufs, serialBufNames);
213  if (!Reader)
214    return nullptr;
215
216  return IntrusiveRefCntPtr<ChainedIncludesSource>(
217      new ChainedIncludesSource(std::move(CIs), Reader));
218}
219