1//===--- GeneratePCH.cpp - Sema Consumer for PCH Generation -----*- 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 PCHGenerator, which as a SemaConsumer that generates
10//  a PCH file.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/AST/ASTContext.h"
15#include "clang/Lex/HeaderSearch.h"
16#include "clang/Lex/Preprocessor.h"
17#include "clang/Sema/SemaConsumer.h"
18#include "clang/Serialization/ASTWriter.h"
19#include "llvm/Bitstream/BitstreamWriter.h"
20
21using namespace clang;
22
23PCHGenerator::PCHGenerator(
24    const Preprocessor &PP, InMemoryModuleCache &ModuleCache,
25    StringRef OutputFile, StringRef isysroot, std::shared_ptr<PCHBuffer> Buffer,
26    ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
27    bool AllowASTWithErrors, bool IncludeTimestamps,
28    bool BuildingImplicitModule, bool ShouldCacheASTInMemory)
29    : PP(PP), OutputFile(OutputFile), isysroot(isysroot.str()),
30      SemaPtr(nullptr), Buffer(std::move(Buffer)), Stream(this->Buffer->Data),
31      Writer(Stream, this->Buffer->Data, ModuleCache, Extensions,
32             IncludeTimestamps, BuildingImplicitModule),
33      AllowASTWithErrors(AllowASTWithErrors),
34      ShouldCacheASTInMemory(ShouldCacheASTInMemory) {
35  this->Buffer->IsComplete = false;
36}
37
38PCHGenerator::~PCHGenerator() {
39}
40
41void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
42  // Don't create a PCH if there were fatal failures during module loading.
43  if (PP.getModuleLoader().HadFatalFailure)
44    return;
45
46  bool hasErrors = PP.getDiagnostics().hasErrorOccurred();
47  if (hasErrors && !AllowASTWithErrors)
48    return;
49
50  Module *Module = nullptr;
51  if (PP.getLangOpts().isCompilingModule()) {
52    Module = PP.getHeaderSearchInfo().lookupModule(
53        PP.getLangOpts().CurrentModule, SourceLocation(),
54        /*AllowSearch*/ false);
55    if (!Module) {
56      assert(hasErrors && "emitting module but current module doesn't exist");
57      return;
58    }
59  }
60
61  // Errors that do not prevent the PCH from being written should not cause the
62  // overall compilation to fail either.
63  if (AllowASTWithErrors)
64    PP.getDiagnostics().getClient()->clear();
65
66  // Emit the PCH file to the Buffer.
67  assert(SemaPtr && "No Sema?");
68  Buffer->Signature = Writer.WriteAST(*SemaPtr, OutputFile, Module, isysroot,
69                                      ShouldCacheASTInMemory);
70
71  Buffer->IsComplete = true;
72}
73
74ASTMutationListener *PCHGenerator::GetASTMutationListener() {
75  return &Writer;
76}
77
78ASTDeserializationListener *PCHGenerator::GetASTDeserializationListener() {
79  return &Writer;
80}
81