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/Bitcode/BitstreamWriter.h"
20 
21 using namespace clang;
22 
23 PCHGenerator::PCHGenerator(
24     const Preprocessor &PP, StringRef OutputFile, StringRef isysroot,
25     std::shared_ptr<PCHBuffer> Buffer,
26     ArrayRef<std::shared_ptr<ModuleFileExtension>> Extensions,
27     bool AllowASTWithErrors, bool IncludeTimestamps)
28     : PP(PP), OutputFile(OutputFile), isysroot(isysroot.str()),
29       SemaPtr(nullptr), Buffer(std::move(Buffer)), Stream(this->Buffer->Data),
30       Writer(Stream, this->Buffer->Data, PP.getPCMCache(), Extensions,
31              IncludeTimestamps),
32       AllowASTWithErrors(AllowASTWithErrors) {
33   this->Buffer->IsComplete = false;
34 }
35 
36 PCHGenerator::~PCHGenerator() {
37 }
38 
39 void PCHGenerator::HandleTranslationUnit(ASTContext &Ctx) {
40   // Don't create a PCH if there were fatal failures during module loading.
41   if (PP.getModuleLoader().HadFatalFailure)
42     return;
43 
44   bool hasErrors = PP.getDiagnostics().hasErrorOccurred();
45   if (hasErrors && !AllowASTWithErrors)
46     return;
47 
48   Module *Module = nullptr;
49   if (PP.getLangOpts().isCompilingModule()) {
50     Module = PP.getHeaderSearchInfo().lookupModule(
51         PP.getLangOpts().CurrentModule, /*AllowSearch*/ false);
52     if (!Module) {
53       assert(hasErrors && "emitting module but current module doesn't exist");
54       return;
55     }
56   }
57 
58   // Emit the PCH file to the Buffer.
59   assert(SemaPtr && "No Sema?");
60   Buffer->Signature =
61       Writer.WriteAST(*SemaPtr, OutputFile, Module, isysroot,
62                       // For serialization we are lenient if the errors were
63                       // only warn-as-error kind.
64                       PP.getDiagnostics().hasUncompilableErrorOccurred());
65 
66   Buffer->IsComplete = true;
67 }
68 
69 ASTMutationListener *PCHGenerator::GetASTMutationListener() {
70   return &Writer;
71 }
72 
73 ASTDeserializationListener *PCHGenerator::GetASTDeserializationListener() {
74   return &Writer;
75 }
76