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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 "llvm/Support/ErrorHandling.h"
     20 
     21 using namespace clang;
     22 
     23 ExternalASTSource::~ExternalASTSource() { }
     24 
     25 void ExternalASTSource::FindFileRegionDecls(FileID File, unsigned Offset,
     26                                             unsigned Length,
     27                                             SmallVectorImpl<Decl *> &Decls) {}
     28 
     29 void ExternalASTSource::CompleteRedeclChain(const Decl *D) {}
     30 
     31 void ExternalASTSource::CompleteType(TagDecl *Tag) {}
     32 
     33 void ExternalASTSource::CompleteType(ObjCInterfaceDecl *Class) {}
     34 
     35 void ExternalASTSource::ReadComments() {}
     36 
     37 void ExternalASTSource::StartedDeserializing() {}
     38 
     39 void ExternalASTSource::FinishedDeserializing() {}
     40 
     41 void ExternalASTSource::StartTranslationUnit(ASTConsumer *Consumer) {}
     42 
     43 void ExternalASTSource::PrintStats() { }
     44 
     45 bool ExternalASTSource::layoutRecordType(
     46     const RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
     47     llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
     48     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
     49     llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets) {
     50   return false;
     51 }
     52 
     53 Decl *ExternalASTSource::GetExternalDecl(uint32_t ID) {
     54   return nullptr;
     55 }
     56 
     57 Selector ExternalASTSource::GetExternalSelector(uint32_t ID) {
     58   return Selector();
     59 }
     60 
     61 uint32_t ExternalASTSource::GetNumExternalSelectors() {
     62    return 0;
     63 }
     64 
     65 Stmt *ExternalASTSource::GetExternalDeclStmt(uint64_t Offset) {
     66   return nullptr;
     67 }
     68 
     69 CXXBaseSpecifier *
     70 ExternalASTSource::GetExternalCXXBaseSpecifiers(uint64_t Offset) {
     71   return nullptr;
     72 }
     73 
     74 bool
     75 ExternalASTSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
     76                                                   DeclarationName Name) {
     77   return false;
     78 }
     79 
     80 void ExternalASTSource::completeVisibleDeclsMap(const DeclContext *DC) {
     81 }
     82 
     83 ExternalLoadResult
     84 ExternalASTSource::FindExternalLexicalDecls(const DeclContext *DC,
     85                                             bool (*isKindWeWant)(Decl::Kind),
     86                                          SmallVectorImpl<Decl*> &Result) {
     87   return ELR_AlreadyLoaded;
     88 }
     89 
     90 void ExternalASTSource::getMemoryBufferSizes(MemoryBufferSizes &sizes) const { }
     91 
     92 uint32_t ExternalASTSource::incrementGeneration(ASTContext &C) {
     93   uint32_t OldGeneration = CurrentGeneration;
     94 
     95   // Make sure the generation of the topmost external source for the context is
     96   // incremented. That might not be us.
     97   auto *P = C.getExternalSource();
     98   if (P && P != this)
     99     CurrentGeneration = P->incrementGeneration(C);
    100   else {
    101     // FIXME: Only bump the generation counter if the current generation number
    102     // has been observed?
    103     if (!++CurrentGeneration)
    104       llvm::report_fatal_error("generation counter overflowed", false);
    105   }
    106 
    107   return OldGeneration;
    108 }
    109