Function definition may have uninstantiated body
Current implementation of `FunctionDecl::isDefined` does not take into
account redeclarations that do not have bodies, but the bodies can be
instantiated from corresponding templated definition. This behavior does
not allow to detect function redefinition in the cases where friend
functions is defined in class templates. For instance, the code:
```
template<typename T> struct X { friend void f() {} };
X<int> xi;
void f() {}
```
compiles successfully but must fail due to redefinition of `f`. The
declaration of the friend `f` is created when the containing template
`X` is instantiated, but it does not have a body as per 14.5.4p4
because `f` is not odr-used.
With this change the function `Sema::CheckForFunctionRedefinition`
considers functions with uninstantiated bodies as definitions.
Differential Revision: https://reviews.llvm.org/D30170
llvm-svn: 326419
diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
index d87f9db..800956d 100644
--- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -1806,45 +1806,24 @@
// apply to non-template function declarations and definitions also apply
// to these implicit definitions.
if (D->isThisDeclarationADefinition()) {
- // Check for a function body.
- const FunctionDecl *Definition = nullptr;
- if (Function->isDefined(Definition) &&
- Definition->getTemplateSpecializationKind() == TSK_Undeclared) {
- SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
- << Function->getDeclName();
- SemaRef.Diag(Definition->getLocation(), diag::note_previous_definition);
- }
- // Check for redefinitions due to other instantiations of this or
- // a similar friend function.
- else for (auto R : Function->redecls()) {
- if (R == Function)
- continue;
+ SemaRef.CheckForFunctionRedefinition(Function);
+ if (!Function->isInvalidDecl()) {
+ for (auto R : Function->redecls()) {
+ if (R == Function)
+ continue;
- // If some prior declaration of this function has been used, we need
- // to instantiate its definition.
- if (!QueuedInstantiation && R->isUsed(false)) {
- if (MemberSpecializationInfo *MSInfo =
- Function->getMemberSpecializationInfo()) {
- if (MSInfo->getPointOfInstantiation().isInvalid()) {
- SourceLocation Loc = R->getLocation(); // FIXME
- MSInfo->setPointOfInstantiation(Loc);
- SemaRef.PendingLocalImplicitInstantiations.push_back(
- std::make_pair(Function, Loc));
- QueuedInstantiation = true;
- }
- }
- }
-
- // If some prior declaration of this function was a friend with an
- // uninstantiated definition, reject it.
- if (R->getFriendObjectKind()) {
- if (const FunctionDecl *RPattern =
- R->getTemplateInstantiationPattern()) {
- if (RPattern->isDefined(RPattern)) {
- SemaRef.Diag(Function->getLocation(), diag::err_redefinition)
- << Function->getDeclName();
- SemaRef.Diag(R->getLocation(), diag::note_previous_definition);
- break;
+ // If some prior declaration of this function has been used, we need
+ // to instantiate its definition.
+ if (!QueuedInstantiation && R->isUsed(false)) {
+ if (MemberSpecializationInfo *MSInfo =
+ Function->getMemberSpecializationInfo()) {
+ if (MSInfo->getPointOfInstantiation().isInvalid()) {
+ SourceLocation Loc = R->getLocation(); // FIXME
+ MSInfo->setPointOfInstantiation(Loc);
+ SemaRef.PendingLocalImplicitInstantiations.push_back(
+ std::make_pair(Function, Loc));
+ QueuedInstantiation = true;
+ }
}
}
}