1 //===- ExternalASTSource.cpp - Abstract External AST Interface ------------===//
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 provides the default implementation of the ExternalASTSource
10 //  interface, which enables construction of AST nodes from some external
11 //  source.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "clang/AST/ExternalASTSource.h"
16 #include "clang/AST/ASTContext.h"
17 #include "clang/AST/DeclarationName.h"
18 #include "clang/Basic/FileManager.h"
19 #include "clang/Basic/IdentifierTable.h"
20 #include "clang/Basic/LLVM.h"
21 #include "clang/Basic/Module.h"
22 #include "clang/Basic/SourceManager.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include <cstdint>
25 #include <optional>
26 
27 using namespace clang;
28 
29 char ExternalASTSource::ID;
30 
31 ExternalASTSource::~ExternalASTSource() = default;
32 
33 std::optional<ASTSourceDescriptor>
34 ExternalASTSource::getSourceDescriptor(unsigned ID) {
35   return std::nullopt;
36 }
37 
38 ExternalASTSource::ExtKind
39 ExternalASTSource::hasExternalDefinitions(const Decl *D) {
40   return EK_ReplyHazy;
41 }
42 
43 void ExternalASTSource::FindFileRegionDecls(FileID File, unsigned Offset,
44                                             unsigned Length,
45                                             SmallVectorImpl<Decl *> &Decls) {}
46 
47 void ExternalASTSource::CompleteRedeclChain(const Decl *D) {}
48 
49 void ExternalASTSource::CompleteType(TagDecl *Tag) {}
50 
51 void ExternalASTSource::CompleteType(ObjCInterfaceDecl *Class) {}
52 
53 void ExternalASTSource::ReadComments() {}
54 
55 void ExternalASTSource::StartedDeserializing() {}
56 
57 void ExternalASTSource::FinishedDeserializing() {}
58 
59 void ExternalASTSource::StartTranslationUnit(ASTConsumer *Consumer) {}
60 
61 void ExternalASTSource::PrintStats() {}
62 
63 bool ExternalASTSource::layoutRecordType(
64     const RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
65     llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
66     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
67     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets) {
68   return false;
69 }
70 
71 Decl *ExternalASTSource::GetExternalDecl(uint32_t ID) {
72   return nullptr;
73 }
74 
75 Selector ExternalASTSource::GetExternalSelector(uint32_t ID) {
76   return Selector();
77 }
78 
79 uint32_t ExternalASTSource::GetNumExternalSelectors() {
80    return 0;
81 }
82 
83 Stmt *ExternalASTSource::GetExternalDeclStmt(uint64_t Offset) {
84   return nullptr;
85 }
86 
87 CXXCtorInitializer **
88 ExternalASTSource::GetExternalCXXCtorInitializers(uint64_t Offset) {
89   return nullptr;
90 }
91 
92 CXXBaseSpecifier *
93 ExternalASTSource::GetExternalCXXBaseSpecifiers(uint64_t Offset) {
94   return nullptr;
95 }
96 
97 bool
98 ExternalASTSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
99                                                   DeclarationName Name) {
100   return false;
101 }
102 
103 void ExternalASTSource::completeVisibleDeclsMap(const DeclContext *DC) {}
104 
105 void ExternalASTSource::FindExternalLexicalDecls(
106     const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant,
107     SmallVectorImpl<Decl *> &Result) {}
108 
109 void ExternalASTSource::getMemoryBufferSizes(MemoryBufferSizes &sizes) const {}
110 
111 uint32_t ExternalASTSource::incrementGeneration(ASTContext &C) {
112   uint32_t OldGeneration = CurrentGeneration;
113 
114   // Make sure the generation of the topmost external source for the context is
115   // incremented. That might not be us.
116   auto *P = C.getExternalSource();
117   if (P && P != this)
118     CurrentGeneration = P->incrementGeneration(C);
119   else {
120     // FIXME: Only bump the generation counter if the current generation number
121     // has been observed?
122     if (!++CurrentGeneration)
123       llvm::report_fatal_error("generation counter overflowed", false);
124   }
125 
126   return OldGeneration;
127 }
128