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Add VarDecl::isThisDeclarationADefinition(), which properly encapsulates the logic for when a variable declaration is a (possibly tentativ) definition. Add a few functions building on this, and shift C tentative definition handling over to this new functionality. This shift also kills the Sema::TentativeDefinitions map and instead simply stores all declarations in the renamed list. The correct handling for multiple tentative definitions is instead shifted to the final walk of the list. 

llvm-svn: 94968
This commit is contained in:
Sebastian Redl 2010-01-31 22:27:38 +00:00
parent a682427e42
commit 35351a9554
7 changed files with 120 additions and 59 deletions
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28
clang/include/clang/AST/Decl.h
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@ -538,6 +538,7 @@ public:
/// };
/// \endcode
bool isStaticDataMember() const {
// If it wasn't static, it would be a FieldDecl.
return getDeclContext()->isRecord();
}
@ -546,6 +547,26 @@ public:
return const_cast<VarDecl*>(this)->getCanonicalDecl();
}
enum DefinitionKind {
DeclarationOnly, ///< This declaration is only a declaration.
TentativeDefinition, ///< This declaration is a tentative definition.
Definition ///< This declaration is definitely a definition.
};
/// \brief Check whether this declaration is a definition. If this could be
/// a tentative definition (in C), don't check whether there's an overriding
/// definition.
DefinitionKind isThisDeclarationADefinition() const;
/// \brief Get the tentative definition that acts as the real definition in
/// a TU. Returns null if there is a proper definition available.
const VarDecl *getActingDefinition() const;
VarDecl *getActingDefinition();
/// \brief Determine whether this is a tentative definition of a
/// variable in C.
bool isTentativeDefinitionNow() const;
/// \brief Retrieve the definition of this variable, which may come
/// from a previous declaration. Def will be set to the VarDecl that
/// contains the initializer, and the result will be that
@ -579,10 +600,9 @@ public:
return false;
}
/// \brief Determine whether this is a tentative definition of a
/// variable in C.
bool isTentativeDefinition(ASTContext &Context) const;
bool hasInit() const {
return !Init.isNull();
}
const Expr *getInit() const {
if (Init.isNull())
return 0;

88
clang/lib/AST/Decl.cpp
View File

@ -480,6 +480,82 @@ VarDecl *VarDecl::getCanonicalDecl() {
return getFirstDeclaration();
}
VarDecl::DefinitionKind VarDecl::isThisDeclarationADefinition() const {
// C++ [basic.def]p2:
// A declaration is a definition unless [...] it contains the 'extern'
// specifier or a linkage-specification and neither an initializer [...],
// it declares a static data member in a class declaration [...].
// C++ [temp.expl.spec]p15:
// An explicit specialization of a static data member of a template is a
// definition if the declaration includes an initializer; otherwise, it is
// a declaration.
if (isStaticDataMember()) {
if (isOutOfLine() && (hasInit() ||
getTemplateSpecializationKind() != TSK_ExplicitSpecialization))
return Definition;
else
return DeclarationOnly;
}
// C99 6.7p5:
// A definition of an identifier is a declaration for that identifier that
// [...] causes storage to be reserved for that object.
// Note: that applies for all non-file-scope objects.
// C99 6.9.2p1:
// If the declaration of an identifier for an object has file scope and an
// initializer, the declaration is an external definition for the identifier
if (hasInit())
return Definition;
// AST for 'extern "C" int foo;' is annotated with 'extern'.
if (hasExternalStorage())
return DeclarationOnly;
// C99 6.9.2p2:
// A declaration of an object that has file scope without an initializer,
// and without a storage class specifier or the scs 'static', constitutes
// a tentative definition.
// No such thing in C++.
if (!getASTContext().getLangOptions().CPlusPlus && isFileVarDecl())
return TentativeDefinition;
// What's left is (in C, block-scope) declarations without initializers or
// external storage. These are definitions.
return Definition;
}
const VarDecl *VarDecl::getActingDefinition() const {
return const_cast<VarDecl*>(this)->getActingDefinition();
}
VarDecl *VarDecl::getActingDefinition() {
DefinitionKind Kind = isThisDeclarationADefinition();
if (Kind != TentativeDefinition)
return 0;
VarDecl *LastTentative = false;
VarDecl *First = getFirstDeclaration();
for (redecl_iterator I = First->redecls_begin(), E = First->redecls_end();
I != E; ++I) {
Kind = (*I)->isThisDeclarationADefinition();
if (Kind == Definition)
return 0;
else if (Kind == TentativeDefinition)
LastTentative = *I;
}
return LastTentative;
}
bool VarDecl::isTentativeDefinitionNow() const {
DefinitionKind Kind = isThisDeclarationADefinition();
if (Kind != TentativeDefinition)
return false;
for (redecl_iterator I = redecls_begin(), E = redecls_end(); I != E; ++I) {
if ((*I)->isThisDeclarationADefinition() == Definition)
return false;
}
return true;
}
const Expr *VarDecl::getDefinition(const VarDecl *&Def) const {
redecl_iterator I = redecls_begin(), E = redecls_end();
while (I != E && !I->getInit())
@ -521,15 +597,6 @@ VarDecl *VarDecl::getOutOfLineDefinition() {
return 0;
}
bool VarDecl::isTentativeDefinition(ASTContext &Context) const {
if (!isFileVarDecl() || Context.getLangOptions().CPlusPlus)
return false;
const VarDecl *Def = 0;
return (!getDefinition(Def) &&
(getStorageClass() == None || getStorageClass() == Static));
}
void VarDecl::setInit(ASTContext &C, Expr *I) {
if (EvaluatedStmt *Eval = Init.dyn_cast<EvaluatedStmt *>()) {
Eval->~EvaluatedStmt();
@ -547,8 +614,7 @@ VarDecl *VarDecl::getInstantiatedFromStaticDataMember() const {
}
TemplateSpecializationKind VarDecl::getTemplateSpecializationKind() const {
if (MemberSpecializationInfo *MSI
= getASTContext().getInstantiatedFromStaticDataMember(this))
if (MemberSpecializationInfo *MSI = getMemberSpecializationInfo())
return MSI->getTemplateSpecializationKind();
return TSK_Undeclared;

5
clang/lib/Frontend/PCHReader.cpp
View File

@ -2464,11 +2464,10 @@ void PCHReader::InitializeSema(Sema &S) {
PreloadedDecls.clear();
// If there were any tentative definitions, deserialize them and add
// them to Sema's table of tentative definitions.
// them to Sema's list of tentative definitions.
for (unsigned I = 0, N = TentativeDefinitions.size(); I != N; ++I) {
VarDecl *Var = cast<VarDecl>(GetDecl(TentativeDefinitions[I]));
SemaObj->TentativeDefinitions[Var->getDeclName()] = Var;
SemaObj->TentativeDefinitionList.push_back(Var->getDeclName());
SemaObj->TentativeDefinitions.push_back(Var);
}
// If there were any locally-scoped external declarations,

8
clang/lib/Frontend/PCHWriter.cpp
View File

@ -1960,13 +1960,11 @@ void PCHWriter::WritePCH(Sema &SemaRef, MemorizeStatCalls *StatCalls,
}
// Build a record containing all of the tentative definitions in this file, in
// TentativeDefinitionList order. Generally, this record will be empty for
// TentativeDefinitions order. Generally, this record will be empty for
// headers.
RecordData TentativeDefinitions;
for (unsigned i = 0, e = SemaRef.TentativeDefinitionList.size(); i != e; ++i){
VarDecl *VD =
SemaRef.TentativeDefinitions.lookup(SemaRef.TentativeDefinitionList[i]);
if (VD) AddDeclRef(VD, TentativeDefinitions);
for (unsigned i = 0, e = SemaRef.TentativeDefinitions.size(); i != e; ++i) {
AddDeclRef(SemaRef.TentativeDefinitions[i], TentativeDefinitions);
}
// Build a record containing all of the locally-scoped external

13
clang/lib/Sema/Sema.cpp
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@ -15,6 +15,7 @@
#include "Sema.h"
#include "TargetAttributesSema.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/APFloat.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
@ -472,12 +473,14 @@ void Sema::ActOnEndOfTranslationUnit() {
// translation unit contains a file scope declaration of that
// identifier, with the composite type as of the end of the
// translation unit, with an initializer equal to 0.
for (unsigned i = 0, e = TentativeDefinitionList.size(); i != e; ++i) {
VarDecl *VD = TentativeDefinitions.lookup(TentativeDefinitionList[i]);
llvm::SmallSet<VarDecl *, 32> Seen;
for (unsigned i = 0, e = TentativeDefinitions.size(); i != e; ++i) {
VarDecl *VD = TentativeDefinitions[i]->getActingDefinition();
// If the tentative definition was completed, it will be in the list, but
// not the map.
if (VD == 0 || VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
// If the tentative definition was completed, getActingDefinition() returns
// null. If we've already seen this variable before, insert()'s second
// return value is false.
if (VD == 0 || VD->isInvalidDecl() || !Seen.insert(VD))
continue;
if (const IncompleteArrayType *ArrayT

10
clang/lib/Sema/Sema.h
View File

@ -272,14 +272,8 @@ public:
/// not visible.
llvm::DenseMap<DeclarationName, NamedDecl *> LocallyScopedExternalDecls;
/// \brief The set of tentative declarations seen so far in this
/// translation unit for which no definition has been seen.
///
/// The tentative declarations are indexed by the name of the
/// declaration, and only the most recent tentative declaration for
/// a given variable will be recorded here.
llvm::DenseMap<DeclarationName, VarDecl *> TentativeDefinitions;
std::vector<DeclarationName> TentativeDefinitionList;
/// \brief All the tentative definitions encountered in the TU.
std::vector<VarDecl *> TentativeDefinitions;
struct DelayedDiagnostic {
enum DDKind { Deprecation, Access };

27
clang/lib/Sema/SemaDecl.cpp
View File

@ -3570,14 +3570,6 @@ void Sema::AddInitializerToDecl(DeclPtrTy dcl, ExprArg init, bool DirectInit) {
// Attach the initializer to the decl.
VDecl->setInit(Context, Init);
// If the previous declaration of VDecl was a tentative definition,
// remove it from the set of tentative definitions.
if (VDecl->getPreviousDeclaration() &&
VDecl->getPreviousDeclaration()->isTentativeDefinition(Context)) {
bool Deleted = TentativeDefinitions.erase(VDecl->getDeclName());
assert(Deleted && "Unrecorded tentative definition?"); Deleted=Deleted;
}
if (getLangOptions().CPlusPlus) {
// Make sure we mark the destructor as used if necessary.
QualType InitType = VDecl->getType();
@ -3602,20 +3594,8 @@ void Sema::ActOnUninitializedDecl(DeclPtrTy dcl,
QualType Type = Var->getType();
// Record tentative definitions.
if (Var->isTentativeDefinition(Context)) {
std::pair<llvm::DenseMap<DeclarationName, VarDecl *>::iterator, bool>
InsertPair =
TentativeDefinitions.insert(std::make_pair(Var->getDeclName(), Var));
// Keep the latest definition in the map. If we see 'int i; int i;' we
// want the second one in the map.
InsertPair.first->second = Var;
// However, for the list, we don't care about the order, just make sure
// that there are no dupes for a given declaration name.
if (InsertPair.second)
TentativeDefinitionList.push_back(Var->getDeclName());
}
if (Var->isTentativeDefinitionNow())
TentativeDefinitions.push_back(Var);
// C++ [dcl.init.ref]p3:
// The initializer can be omitted for a reference only in a
@ -3794,7 +3774,8 @@ Sema::DeclGroupPtrTy Sema::FinalizeDeclaratorGroup(Scope *S, const DeclSpec &DS,
// storage-class specifier or with the storage-class specifier "static",
// constitutes a tentative definition. Note: A tentative definition with
// external linkage is valid (C99 6.2.2p5).
if (IDecl->isTentativeDefinition(Context) && !IDecl->isInvalidDecl()) {
if (IDecl->isThisDeclarationADefinition() == VarDecl::TentativeDefinition &&
!IDecl->isInvalidDecl()) {
if (const IncompleteArrayType *ArrayT
= Context.getAsIncompleteArrayType(T)) {
if (RequireCompleteType(IDecl->getLocation(),