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/Basic/DiagnosticFrontend.h"
16#include "clang/Lex/HeaderSearch.h"
17#include "clang/Lex/HeaderSearchOptions.h"
18#include "clang/Lex/Preprocessor.h"
19#include "clang/Sema/SemaConsumer.h"
20#include "clang/Serialization/ASTWriter.h"
21#include "llvm/Bitstream/BitstreamWriter.h"
22
23using namespace clang;
24
25PCHGenerator::PCHGenerator(
26 Preprocessor &PP, ModuleCache &ModCache, StringRef OutputFile,
27 StringRef isysroot, std::shared_ptr<PCHBuffer> Buffer,
28 const CodeGenOptions &CodeGenOpts,
29 ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
30 bool AllowASTWithErrors, bool IncludeTimestamps,
31 bool BuildingImplicitModule, bool ShouldCacheASTInMemory,
32 bool GeneratingReducedBMI)
33 : PP(PP), Subject(&PP), OutputFile(OutputFile), isysroot(isysroot.str()),
34 Buffer(std::move(Buffer)), Stream(this->Buffer->Data),
35 Writer(Stream, this->Buffer->Data, ModCache, CodeGenOpts, Extensions,
36 IncludeTimestamps, BuildingImplicitModule, GeneratingReducedBMI),
37 AllowASTWithErrors(AllowASTWithErrors),
38 ShouldCacheASTInMemory(ShouldCacheASTInMemory) {
39 this->Buffer->IsComplete = false;
40}
41
42PCHGenerator::~PCHGenerator() {
43}
44
45Module *PCHGenerator::getEmittingModule(ASTContext &) {
46 Module *M = nullptr;
47
48 if (PP.getLangOpts().isCompilingModule()) {
49 M = PP.getHeaderSearchInfo().lookupModule(ModuleName: PP.getLangOpts().CurrentModule,
50 ImportLoc: SourceLocation(),
51 /*AllowSearch*/ false);
52 if (!M)
53 assert(PP.getDiagnostics().hasErrorOccurred() &&
54 "emitting module but current module doesn't exist");
55 }
56
57 return M;
58}
59
60DiagnosticsEngine &PCHGenerator::getDiagnostics() const {
61 return PP.getDiagnostics();
62}
63
64void PCHGenerator::InitializeSema(Sema &S) {
65 if (!PP.getHeaderSearchInfo()
66 .getHeaderSearchOpts()
67 .ModulesSerializeOnlyPreprocessor)
68 Subject = &S;
69}
70
71void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
72 // Don't create a PCH if there were fatal failures during module loading.
73 if (PP.getModuleLoader().HadFatalFailure)
74 return;
75
76 bool hasErrors = PP.getDiagnostics().hasErrorOccurred();
77 if (hasErrors && !AllowASTWithErrors)
78 return;
79
80 Module *Module = getEmittingModule(Ctx);
81
82 // Errors that do not prevent the PCH from being written should not cause the
83 // overall compilation to fail either.
84 if (AllowASTWithErrors)
85 PP.getDiagnostics().getClient()->clear();
86
87 Buffer->Signature = Writer.WriteAST(Subject, OutputFile, WritingModule: Module, isysroot,
88 ShouldCacheASTInMemory);
89
90 Buffer->IsComplete = true;
91}
92
93ASTMutationListener *PCHGenerator::GetASTMutationListener() {
94 return &Writer;
95}
96
97ASTDeserializationListener *PCHGenerator::GetASTDeserializationListener() {
98 return &Writer;
99}
100
101void PCHGenerator::anchor() {}
102
103CXX20ModulesGenerator::CXX20ModulesGenerator(Preprocessor &PP,
104 ModuleCache &ModCache,
105 StringRef OutputFile,
106 const CodeGenOptions &CodeGenOpts,
107 bool GeneratingReducedBMI,
108 bool AllowASTWithErrors)
109 : PCHGenerator(
110 PP, ModCache, OutputFile, llvm::StringRef(),
111 std::make_shared<PCHBuffer>(), CodeGenOpts,
112 /*Extensions=*/ArrayRef<std::shared_ptr<ModuleFileExtension>>(),
113 AllowASTWithErrors, /*IncludeTimestamps=*/false,
114 /*BuildingImplicitModule=*/false, /*ShouldCacheASTInMemory=*/false,
115 GeneratingReducedBMI) {}
116
117Module *CXX20ModulesGenerator::getEmittingModule(ASTContext &Ctx) {
118 Module *M = Ctx.getCurrentNamedModule();
119 assert(M && M->isNamedModuleUnit() &&
120 "CXX20ModulesGenerator should only be used with C++20 Named modules.");
121 return M;
122}
123
124void CXX20ModulesGenerator::HandleTranslationUnit(ASTContext &Ctx) {
125 PCHGenerator::HandleTranslationUnit(Ctx);
126
127 if (!isComplete())
128 return;
129
130 std::error_code EC;
131 auto OS = std::make_unique<llvm::raw_fd_ostream>(args: getOutputFile(), args&: EC);
132 if (EC) {
133 getDiagnostics().Report(DiagID: diag::err_fe_unable_to_open_output)
134 << getOutputFile() << EC.message() << "\n";
135 return;
136 }
137
138 *OS << getBufferPtr()->Data;
139 OS->flush();
140}
141
142void CXX20ModulesGenerator::anchor() {}
143
144void ReducedBMIGenerator::anchor() {}
145