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 ChainedIncludesSource : public ExternalSemaSource {
31public:
32  ChainedIncludesSource(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} // end anonymous namespace
55
56static ASTReader *
57createASTReader(CompilerInstance &CI, StringRef pchFile,
58                SmallVectorImpl<std::unique_ptr<llvm::MemoryBuffer>> &MemBufs,
59                SmallVectorImpl<std::string> &bufNames,
60                ASTDeserializationListener *deserialListener = nullptr) {
61  Preprocessor &PP = CI.getPreprocessor();
62  std::unique_ptr<ASTReader> Reader;
63  Reader.reset(new ASTReader(
64      PP, CI.getModuleCache(), &CI.getASTContext(), CI.getPCHContainerReader(),
65      /*Extensions=*/{},
66      /*isysroot=*/"", DisableValidationForModuleKind::PCH));
67  for (unsigned ti = 0; ti < bufNames.size(); ++ti) {
68    StringRef sr(bufNames[ti]);
69    Reader->addInMemoryBuffer(sr, std::move(MemBufs[ti]));
70  }
71  Reader->setDeserializationListener(deserialListener);
72  switch (Reader->ReadAST(pchFile, serialization::MK_PCH, SourceLocation(),
73                          ASTReader::ARR_None)) {
74  case ASTReader::Success:
75    // Set the predefines buffer as suggested by the PCH reader.
76    PP.setPredefines(Reader->getSuggestedPredefines());
77    return Reader.release();
78
79  case ASTReader::Failure:
80  case ASTReader::Missing:
81  case ASTReader::OutOfDate:
82  case ASTReader::VersionMismatch:
83  case ASTReader::ConfigurationMismatch:
84  case ASTReader::HadErrors:
85    break;
86  }
87  return nullptr;
88}
89
90IntrusiveRefCntPtr<ExternalSemaSource> clang::createChainedIncludesSource(
91    CompilerInstance &CI, IntrusiveRefCntPtr<ExternalSemaSource> &Reader) {
92
93  std::vector<std::string> &includes = CI.getPreprocessorOpts().ChainedIncludes;
94  assert(!includes.empty() && "No '-chain-include' in options!");
95
96  std::vector<std::unique_ptr<CompilerInstance>> CIs;
97  InputKind IK = CI.getFrontendOpts().Inputs[0].getKind();
98
99  SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> SerialBufs;
100  SmallVector<std::string, 4> serialBufNames;
101
102  for (unsigned i = 0, e = includes.size(); i != e; ++i) {
103    bool firstInclude = (i == 0);
104    std::unique_ptr<CompilerInvocation> CInvok;
105    CInvok.reset(new CompilerInvocation(CI.getInvocation()));
106
107    CInvok->getPreprocessorOpts().ChainedIncludes.clear();
108    CInvok->getPreprocessorOpts().ImplicitPCHInclude.clear();
109    CInvok->getPreprocessorOpts().DisablePCHOrModuleValidation =
110        DisableValidationForModuleKind::PCH;
111    CInvok->getPreprocessorOpts().Includes.clear();
112    CInvok->getPreprocessorOpts().MacroIncludes.clear();
113    CInvok->getPreprocessorOpts().Macros.clear();
114
115    CInvok->getFrontendOpts().Inputs.clear();
116    FrontendInputFile InputFile(includes[i], IK);
117    CInvok->getFrontendOpts().Inputs.push_back(InputFile);
118
119    TextDiagnosticPrinter *DiagClient =
120      new TextDiagnosticPrinter(llvm::errs(), new DiagnosticOptions());
121    IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
122    IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
123        new DiagnosticsEngine(DiagID, &CI.getDiagnosticOpts(), DiagClient));
124
125    std::unique_ptr<CompilerInstance> Clang(
126        new CompilerInstance(CI.getPCHContainerOperations()));
127    Clang->setInvocation(std::move(CInvok));
128    Clang->setDiagnostics(Diags.get());
129    Clang->setTarget(TargetInfo::CreateTargetInfo(
130        Clang->getDiagnostics(), Clang->getInvocation().TargetOpts));
131    Clang->createFileManager();
132    Clang->createSourceManager(Clang->getFileManager());
133    Clang->createPreprocessor(TU_Prefix);
134    Clang->getDiagnosticClient().BeginSourceFile(Clang->getLangOpts(),
135                                                 &Clang->getPreprocessor());
136    Clang->createASTContext();
137
138    auto Buffer = std::make_shared<PCHBuffer>();
139    ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions;
140    auto consumer = std::make_unique<PCHGenerator>(
141        Clang->getPreprocessor(), Clang->getModuleCache(), "-", /*isysroot=*/"",
142        Buffer, Extensions, /*AllowASTWithErrors=*/true);
143    Clang->getASTContext().setASTMutationListener(
144                                            consumer->GetASTMutationListener());
145    Clang->setASTConsumer(std::move(consumer));
146    Clang->createSema(TU_Prefix, nullptr);
147
148    if (firstInclude) {
149      Preprocessor &PP = Clang->getPreprocessor();
150      PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
151                                             PP.getLangOpts());
152    } else {
153      assert(!SerialBufs.empty());
154      SmallVector<std::unique_ptr<llvm::MemoryBuffer>, 4> Bufs;
155      // TODO: Pass through the existing MemoryBuffer instances instead of
156      // allocating new ones.
157      for (auto &SB : SerialBufs)
158        Bufs.push_back(llvm::MemoryBuffer::getMemBuffer(SB->getBuffer()));
159      std::string pchName = includes[i-1];
160      llvm::raw_string_ostream os(pchName);
161      os << ".pch" << i-1;
162      serialBufNames.push_back(os.str());
163
164      IntrusiveRefCntPtr<ASTReader> Reader;
165      Reader = createASTReader(
166          *Clang, pchName, Bufs, serialBufNames,
167          Clang->getASTConsumer().GetASTDeserializationListener());
168      if (!Reader)
169        return nullptr;
170      Clang->setASTReader(Reader);
171      Clang->getASTContext().setExternalSource(Reader);
172    }
173
174    if (!Clang->InitializeSourceManager(InputFile))
175      return nullptr;
176
177    ParseAST(Clang->getSema());
178    Clang->getDiagnosticClient().EndSourceFile();
179    assert(Buffer->IsComplete && "serialization did not complete");
180    auto &serialAST = Buffer->Data;
181    SerialBufs.push_back(llvm::MemoryBuffer::getMemBufferCopy(
182        StringRef(serialAST.data(), serialAST.size())));
183    serialAST.clear();
184    CIs.push_back(std::move(Clang));
185  }
186
187  assert(!SerialBufs.empty());
188  std::string pchName = includes.back() + ".pch-final";
189  serialBufNames.push_back(pchName);
190  Reader = createASTReader(CI, pchName, SerialBufs, serialBufNames);
191  if (!Reader)
192    return nullptr;
193
194  auto ChainedSrc =
195      llvm::makeIntrusiveRefCnt<ChainedIncludesSource>(std::move(CIs));
196  return llvm::makeIntrusiveRefCnt<MultiplexExternalSemaSource>(
197      ChainedSrc.get(), Reader.get());
198}
199