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//===- IdentifierResolver.cpp - Lexical Scope Name lookup -------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the IdentifierResolver class, which is used for lexical
// scoped lookup, based on declaration names.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/IdentifierResolver.h"
#include "clang/AST/Decl.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Lex/ExternalPreprocessorSource.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Scope.h"
using namespace clang;
//===----------------------------------------------------------------------===//
// IdDeclInfoMap class
//===----------------------------------------------------------------------===//
/// IdDeclInfoMap - Associates IdDeclInfos with declaration names.
/// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each
/// individual IdDeclInfo to heap.
class IdentifierResolver::IdDeclInfoMap {
static const unsigned int POOL_SIZE = 512;
/// We use our own linked-list implementation because it is sadly
/// impossible to add something to a pre-C++0x STL container without
/// a completely unnecessary copy.
struct IdDeclInfoPool {
IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {}
IdDeclInfoPool *Next;
IdDeclInfo Pool[POOL_SIZE];
};
IdDeclInfoPool *CurPool;
unsigned int CurIndex;
public:
IdDeclInfoMap() : CurPool(nullptr), CurIndex(POOL_SIZE) {}
~IdDeclInfoMap() {
IdDeclInfoPool *Cur = CurPool;
while (IdDeclInfoPool *P = Cur) {
Cur = Cur->Next;
delete P;
}
}
/// Returns the IdDeclInfo associated to the DeclarationName.
/// It creates a new IdDeclInfo if one was not created before for this id.
IdDeclInfo &operator[](DeclarationName Name);
};
//===----------------------------------------------------------------------===//
// IdDeclInfo Implementation
//===----------------------------------------------------------------------===//
/// RemoveDecl - Remove the decl from the scope chain.
/// The decl must already be part of the decl chain.
void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
if (D == *(I-1)) {
Decls.erase(I-1);
return;
}
}
llvm_unreachable("Didn't find this decl on its identifier's chain!");
}
//===----------------------------------------------------------------------===//
// IdentifierResolver Implementation
//===----------------------------------------------------------------------===//
IdentifierResolver::IdentifierResolver(Preprocessor &PP)
: LangOpt(PP.getLangOpts()), PP(PP),
IdDeclInfos(new IdDeclInfoMap) {
}
IdentifierResolver::~IdentifierResolver() {
delete IdDeclInfos;
}
/// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
/// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
/// true if 'D' belongs to the given declaration context.
bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S,
bool AllowInlineNamespace) const {
Ctx = Ctx->getRedeclContext();
if (Ctx->isFunctionOrMethod() || (S && S->isFunctionPrototypeScope())) {
// Ignore the scopes associated within transparent declaration contexts.
while (S->getEntity() && S->getEntity()->isTransparentContext())
S = S->getParent();
if (S->isDeclScope(D))
return true;
if (LangOpt.CPlusPlus) {
// C++ 3.3.2p3:
// The name declared in a catch exception-declaration is local to the
// handler and shall not be redeclared in the outermost block of the
// handler.
// C++ 3.3.2p4:
// Names declared in the for-init-statement, and in the condition of if,
// while, for, and switch statements are local to the if, while, for, or
// switch statement (including the controlled statement), and shall not be
// redeclared in a subsequent condition of that statement nor in the
// outermost block (or, for the if statement, any of the outermost blocks)
// of the controlled statement.
//
assert(S->getParent() && "No TUScope?");
if (S->getParent()->getFlags() & Scope::ControlScope) {
S = S->getParent();
if (S->isDeclScope(D))
return true;
}
if (S->getFlags() & Scope::FnTryCatchScope)
return S->getParent()->isDeclScope(D);
}
return false;
}
// FIXME: If D is a local extern declaration, this check doesn't make sense;
// we should be checking its lexical context instead in that case, because
// that is its scope.
DeclContext *DCtx = D->getDeclContext()->getRedeclContext();
return AllowInlineNamespace ? Ctx->InEnclosingNamespaceSetOf(DCtx)
: Ctx->Equals(DCtx);
}
/// AddDecl - Link the decl to its shadowed decl chain.
void IdentifierResolver::AddDecl(NamedDecl *D) {
DeclarationName Name = D->getDeclName();
if (IdentifierInfo *II = Name.getAsIdentifierInfo())
updatingIdentifier(*II);
void *Ptr = Name.getFETokenInfo<void>();
if (!Ptr) {
Name.setFETokenInfo(D);
return;
}
IdDeclInfo *IDI;
if (isDeclPtr(Ptr)) {
Name.setFETokenInfo(nullptr);
IDI = &(*IdDeclInfos)[Name];
NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
IDI->AddDecl(PrevD);
} else
IDI = toIdDeclInfo(Ptr);
IDI->AddDecl(D);
}
void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) {
DeclarationName Name = D->getDeclName();
if (IdentifierInfo *II = Name.getAsIdentifierInfo())
updatingIdentifier(*II);
void *Ptr = Name.getFETokenInfo<void>();
if (!Ptr) {
AddDecl(D);
return;
}
if (isDeclPtr(Ptr)) {
// We only have a single declaration: insert before or after it,
// as appropriate.
if (Pos == iterator()) {
// Add the new declaration before the existing declaration.
NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
RemoveDecl(PrevD);
AddDecl(D);
AddDecl(PrevD);
} else {
// Add new declaration after the existing declaration.
AddDecl(D);
}
return;
}
// General case: insert the declaration at the appropriate point in the
// list, which already has at least two elements.
IdDeclInfo *IDI = toIdDeclInfo(Ptr);
if (Pos.isIterator()) {
IDI->InsertDecl(Pos.getIterator() + 1, D);
} else
IDI->InsertDecl(IDI->decls_begin(), D);
}
/// RemoveDecl - Unlink the decl from its shadowed decl chain.
/// The decl must already be part of the decl chain.
void IdentifierResolver::RemoveDecl(NamedDecl *D) {
assert(D && "null param passed");
DeclarationName Name = D->getDeclName();
if (IdentifierInfo *II = Name.getAsIdentifierInfo())
updatingIdentifier(*II);
void *Ptr = Name.getFETokenInfo<void>();
assert(Ptr && "Didn't find this decl on its identifier's chain!");
if (isDeclPtr(Ptr)) {
assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
Name.setFETokenInfo(nullptr);
return;
}
return toIdDeclInfo(Ptr)->RemoveDecl(D);
}
/// begin - Returns an iterator for decls with name 'Name'.
IdentifierResolver::iterator
IdentifierResolver::begin(DeclarationName Name) {
if (IdentifierInfo *II = Name.getAsIdentifierInfo())
readingIdentifier(*II);
void *Ptr = Name.getFETokenInfo<void>();
if (!Ptr) return end();
if (isDeclPtr(Ptr))
return iterator(static_cast<NamedDecl*>(Ptr));
IdDeclInfo *IDI = toIdDeclInfo(Ptr);
IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
if (I != IDI->decls_begin())
return iterator(I-1);
// No decls found.
return end();
}
namespace {
enum DeclMatchKind {
DMK_Different,
DMK_Replace,
DMK_Ignore
};
}
/// \brief Compare two declarations to see whether they are different or,
/// if they are the same, whether the new declaration should replace the
/// existing declaration.
static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) {
// If the declarations are identical, ignore the new one.
if (Existing == New)
return DMK_Ignore;
// If the declarations have different kinds, they're obviously different.
if (Existing->getKind() != New->getKind())
return DMK_Different;
// If the declarations are redeclarations of each other, keep the newest one.
if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) {
// If we're adding an imported declaration, don't replace another imported
// declaration.
if (Existing->isFromASTFile() && New->isFromASTFile())
return DMK_Different;
// If either of these is the most recent declaration, use it.
Decl *MostRecent = Existing->getMostRecentDecl();
if (Existing == MostRecent)
return DMK_Ignore;
if (New == MostRecent)
return DMK_Replace;
// If the existing declaration is somewhere in the previous declaration
// chain of the new declaration, then prefer the new declaration.
for (auto RD : New->redecls()) {
if (RD == Existing)
return DMK_Replace;
if (RD->isCanonicalDecl())
break;
}
return DMK_Ignore;
}
return DMK_Different;
}
bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){
if (IdentifierInfo *II = Name.getAsIdentifierInfo())
readingIdentifier(*II);
void *Ptr = Name.getFETokenInfo<void>();
if (!Ptr) {
Name.setFETokenInfo(D);
return true;
}
IdDeclInfo *IDI;
if (isDeclPtr(Ptr)) {
NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
switch (compareDeclarations(PrevD, D)) {
case DMK_Different:
break;
case DMK_Ignore:
return false;
case DMK_Replace:
Name.setFETokenInfo(D);
return true;
}
Name.setFETokenInfo(nullptr);
IDI = &(*IdDeclInfos)[Name];
// If the existing declaration is not visible in translation unit scope,
// then add the new top-level declaration first.
if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
IDI->AddDecl(D);
IDI->AddDecl(PrevD);
} else {
IDI->AddDecl(PrevD);
IDI->AddDecl(D);
}
return true;
}
IDI = toIdDeclInfo(Ptr);
// See whether this declaration is identical to any existing declarations.
// If not, find the right place to insert it.
for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(),
IEnd = IDI->decls_end();
I != IEnd; ++I) {
switch (compareDeclarations(*I, D)) {
case DMK_Different:
break;
case DMK_Ignore:
return false;
case DMK_Replace:
*I = D;
return true;
}
if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
// We've found a declaration that is not visible from the translation
// unit (it's in an inner scope). Insert our declaration here.
IDI->InsertDecl(I, D);
return true;
}
}
// Add the declaration to the end.
IDI->AddDecl(D);
return true;
}
void IdentifierResolver::readingIdentifier(IdentifierInfo &II) {
if (II.isOutOfDate())
PP.getExternalSource()->updateOutOfDateIdentifier(II);
}
void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) {
if (II.isOutOfDate())
PP.getExternalSource()->updateOutOfDateIdentifier(II);
if (II.isFromAST())
II.setFETokenInfoChangedSinceDeserialization();
}
//===----------------------------------------------------------------------===//
// IdDeclInfoMap Implementation
//===----------------------------------------------------------------------===//
/// Returns the IdDeclInfo associated to the DeclarationName.
/// It creates a new IdDeclInfo if one was not created before for this id.
IdentifierResolver::IdDeclInfo &
IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) {
void *Ptr = Name.getFETokenInfo<void>();
if (Ptr) return *toIdDeclInfo(Ptr);
if (CurIndex == POOL_SIZE) {
CurPool = new IdDeclInfoPool(CurPool);
CurIndex = 0;
}
IdDeclInfo *IDI = &CurPool->Pool[CurIndex];
Name.setFETokenInfo(reinterpret_cast<void*>(
reinterpret_cast<uintptr_t>(IDI) | 0x1)
);
++CurIndex;
return *IDI;
}
void IdentifierResolver::iterator::incrementSlowCase() {
NamedDecl *D = **this;
void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
BaseIter I = getIterator();
if (I != Info->decls_begin())
*this = iterator(I-1);
else // No more decls.
*this = iterator();
}