llvm-project/clang/lib/AST/ExternalASTSource.cpp
Raphael Isemann aa4558497f [clang] Improve LLVM-style RTTI support in ExternalASTSource/ExternalSemaSource
Summary:
We currently have some very basic LLVM-style RTTI support in the ExternalASTSource class hierarchy
based on the `SemaSource` bool( to discriminate it form the ExternalSemaSource). As ExternalASTSource
is supposed to be subclassed we should have extendable LLVM-style RTTI in this class hierarchy to make life easier
for projects building on top of Clang.

Most notably the current RTTI implementation forces LLDB to implement RTTI for its
own ExternalASTSource class (ClangExternalASTSourceCommon) by keeping a global set of
ExternalASTSources that are known to be ClangExternalASTSourceCommon. Projects
using Clang currently have to dosimilar workarounds to get RTTI support for their subclasses.

This patch turns this into full-fledged LLVM-style RTTI based on a static `ID` variable similar to
other LLVM class hierarchies. Also removes the friend declaration from ExternalASTSource to
its child class that was only used to grant access to the `SemaSource` member.

Reviewers: aprantl, dblaikie, rjmccall

Reviewed By: aprantl

Subscribers: riccibruno, labath, lhames, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71397
2019-12-15 18:11:01 +01:00

141 lines
4.2 KiB
C++

//===- ExternalASTSource.cpp - Abstract External AST Interface ------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides the default implementation of the ExternalASTSource
// interface, which enables construction of AST nodes from some external
// source.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclarationName.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/Module.h"
#include "llvm/ADT/None.h"
#include "llvm/Support/ErrorHandling.h"
#include <cstdint>
using namespace clang;
char ExternalASTSource::ID;
ExternalASTSource::~ExternalASTSource() = default;
llvm::Optional<ExternalASTSource::ASTSourceDescriptor>
ExternalASTSource::getSourceDescriptor(unsigned ID) {
return None;
}
ExternalASTSource::ExtKind
ExternalASTSource::hasExternalDefinitions(const Decl *D) {
return EK_ReplyHazy;
}
ExternalASTSource::ASTSourceDescriptor::ASTSourceDescriptor(const Module &M)
: Signature(M.Signature), ClangModule(&M) {
if (M.Directory)
Path = M.Directory->getName();
if (auto *File = M.getASTFile())
ASTFile = File->getName();
}
std::string ExternalASTSource::ASTSourceDescriptor::getModuleName() const {
if (ClangModule)
return ClangModule->Name;
else
return PCHModuleName;
}
void ExternalASTSource::FindFileRegionDecls(FileID File, unsigned Offset,
unsigned Length,
SmallVectorImpl<Decl *> &Decls) {}
void ExternalASTSource::CompleteRedeclChain(const Decl *D) {}
void ExternalASTSource::CompleteType(TagDecl *Tag) {}
void ExternalASTSource::CompleteType(ObjCInterfaceDecl *Class) {}
void ExternalASTSource::ReadComments() {}
void ExternalASTSource::StartedDeserializing() {}
void ExternalASTSource::FinishedDeserializing() {}
void ExternalASTSource::StartTranslationUnit(ASTConsumer *Consumer) {}
void ExternalASTSource::PrintStats() {}
bool ExternalASTSource::layoutRecordType(
const RecordDecl *Record, uint64_t &Size, uint64_t &Alignment,
llvm::DenseMap<const FieldDecl *, uint64_t> &FieldOffsets,
llvm::DenseMap<const CXXRecordDecl *, CharUnits> &BaseOffsets,
llvm::DenseMap<const CXXRecordDecl *, CharUnits> &VirtualBaseOffsets) {
return false;
}
Decl *ExternalASTSource::GetExternalDecl(uint32_t ID) {
return nullptr;
}
Selector ExternalASTSource::GetExternalSelector(uint32_t ID) {
return Selector();
}
uint32_t ExternalASTSource::GetNumExternalSelectors() {
return 0;
}
Stmt *ExternalASTSource::GetExternalDeclStmt(uint64_t Offset) {
return nullptr;
}
CXXCtorInitializer **
ExternalASTSource::GetExternalCXXCtorInitializers(uint64_t Offset) {
return nullptr;
}
CXXBaseSpecifier *
ExternalASTSource::GetExternalCXXBaseSpecifiers(uint64_t Offset) {
return nullptr;
}
bool
ExternalASTSource::FindExternalVisibleDeclsByName(const DeclContext *DC,
DeclarationName Name) {
return false;
}
void ExternalASTSource::completeVisibleDeclsMap(const DeclContext *DC) {}
void ExternalASTSource::FindExternalLexicalDecls(
const DeclContext *DC, llvm::function_ref<bool(Decl::Kind)> IsKindWeWant,
SmallVectorImpl<Decl *> &Result) {}
void ExternalASTSource::getMemoryBufferSizes(MemoryBufferSizes &sizes) const {}
uint32_t ExternalASTSource::incrementGeneration(ASTContext &C) {
uint32_t OldGeneration = CurrentGeneration;
// Make sure the generation of the topmost external source for the context is
// incremented. That might not be us.
auto *P = C.getExternalSource();
if (P && P != this)
CurrentGeneration = P->incrementGeneration(C);
else {
// FIXME: Only bump the generation counter if the current generation number
// has been observed?
if (!++CurrentGeneration)
llvm::report_fatal_error("generation counter overflowed", false);
}
return OldGeneration;
}