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      1 //===- ExternalASTSource.cpp - Abstract External AST Interface --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file provides the default implementation of the ExternalASTSource
     11 //  interface, which enables construction of AST nodes from some external
     12 //  source.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #include "clang/AST/ExternalASTSource.h"
     17 #include "clang/AST/ASTContext.h"
     18 #include "clang/AST/DeclarationName.h"
     19 #include "clang/Basic/Module.h"
     20 #include "llvm/Support/ErrorHandling.h"
     21 
     22 using namespace clang;
     23 
     24 ExternalASTSource::~ExternalASTSource() { }
     25 
     26 llvm::Optional<ExternalASTSource::ASTSourceDescriptor>
     27 ExternalASTSource::getSourceDescriptor(unsigned ID) {
     28   return None;
     29 }
     30 
     31 ExternalASTSource::ASTSourceDescriptor::ASTSourceDescriptor(const Module &M)
     32   : Signature(M.Signature), ClangModule(&M) {
     33   if (M.Directory)
     34     Path = M.Directory->getName();
     35   if (auto *File = M.getASTFile())
     36     ASTFile = File->getName();
     37 }
     38 
     39 std::string ExternalASTSource::ASTSourceDescriptor::getModuleName() const {
     40   if (ClangModule)
     41     return ClangModule->Name;
     42   else
     43     return PCHModuleName;
     44 }
     45 
     46 void ExternalASTSource::FindFileRegionDecls(FileID File, unsigned Offset,
     47                                             unsigned Length,
     48                                             SmallVectorImpl<Decl *> &Decls) {}
     49 
     50 void ExternalASTSource::CompleteRedeclChain(const Decl *D) {}
     51 
     52 void ExternalASTSource::CompleteType(TagDecl *Tag) {}
     53 
     54 void ExternalASTSource::CompleteType(ObjCInterfaceDecl *Class) {}
     55 
     56 void ExternalASTSource::ReadComments() {}
     57 
     58 void ExternalASTSource::StartedDeserializing() {}
     59 
     60 void ExternalASTSource::FinishedDeserializing() {}
     61 
     62 void ExternalASTSource::StartTranslationUnit(ASTConsumer *Consumer) {}
     63 
     64 void ExternalASTSource::PrintStats() { }
     65 
     66 bool ExternalASTSource::layoutRecordType(
     67     const RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
     68     llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
     69     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
     70     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets) {
     71   return false;
     72 }
     73 
     74 Decl *ExternalASTSource::GetExternalDecl(uint32_t ID) {
     75   return nullptr;
     76 }
     77 
     78 Selector ExternalASTSource::GetExternalSelector(uint32_t ID) {
     79   return Selector();
     80 }
     81 
     82 uint32_t ExternalASTSource::GetNumExternalSelectors() {
     83    return 0;
     84 }
     85 
     86 Stmt *ExternalASTSource::GetExternalDeclStmt(uint64_t Offset) {
     87   return nullptr;
     88 }
     89 
     90 CXXCtorInitializer **
     91 ExternalASTSource::GetExternalCXXCtorInitializers(uint64_t Offset) {
     92   return nullptr;
     93 }
     94 
     95 CXXBaseSpecifier *
     96 ExternalASTSource::GetExternalCXXBaseSpecifiers(uint64_t Offset) {
     97   return nullptr;
     98 }
     99 
    100 bool
    101 ExternalASTSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
    102                                                   DeclarationName Name) {
    103   return false;
    104 }
    105 
    106 void ExternalASTSource::completeVisibleDeclsMap(const DeclContext *DC) {}
    107 
    108 void ExternalASTSource::FindExternalLexicalDecls(
    109     const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant,
    110     SmallVectorImpl<Decl *> &Result) {}
    111 
    112 void ExternalASTSource::getMemoryBufferSizes(MemoryBufferSizes &sizes) const {}
    113 
    114 uint32_t ExternalASTSource::incrementGeneration(ASTContext &C) {
    115   uint32_t OldGeneration = CurrentGeneration;
    116 
    117   // Make sure the generation of the topmost external source for the context is
    118   // incremented. That might not be us.
    119   auto *P = C.getExternalSource();
    120   if (P && P != this)
    121     CurrentGeneration = P->incrementGeneration(C);
    122   else {
    123     // FIXME: Only bump the generation counter if the current generation number
    124     // has been observed?
    125     if (!++CurrentGeneration)
    126       llvm::report_fatal_error("generation counter overflowed", false);
    127   }
    128 
    129   return OldGeneration;
    130 }
    131