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      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/ADT/None.h"
     24 #include "llvm/Support/ErrorHandling.h"
     25 #include <cstdint>
     26 
     27 using namespace clang;
     28 
     29 char ExternalASTSource::ID;
     30 
     31 ExternalASTSource::~ExternalASTSource() = default;
     32 
     33 llvm::Optional<ASTSourceDescriptor>
     34 ExternalASTSource::getSourceDescriptor(unsigned ID) {
     35   return None;
     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