Introduce a new expression type, UnresolvedDeclRefExpr, that describes
dependent qualified-ids such as
Fibonacci<N - 1>::value
where N is a template parameter. These references are "unresolved"
because the name is dependent and, therefore, cannot be resolved to a
declaration node (as we would do for a DeclRefExpr or
QualifiedDeclRefExpr). UnresolvedDeclRefExprs instantiate to
DeclRefExprs, QualifiedDeclRefExprs, etc.
Also, be a bit more careful about keeping only a single set of
specializations for a class template, and instantiating from the
definition of that template rather than a previous declaration. In
general, we need a better solution for this for all TagDecls, because
it's too easy to accidentally look at a declaration that isn't the
definition.
We can now process a simple Fibonacci computation described as a
template metaprogram.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@67308 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 7df9941..10f9926 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -625,6 +625,7 @@
OwningExprResult VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E);
OwningExprResult VisitConditionalOperator(ConditionalOperator *E);
OwningExprResult VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E);
+ OwningExprResult VisitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *E);
OwningExprResult VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *E);
OwningExprResult VisitImplicitCastExpr(ImplicitCastExpr *E);
@@ -897,6 +898,26 @@
}
Sema::OwningExprResult
+TemplateExprInstantiator::VisitUnresolvedDeclRefExpr(UnresolvedDeclRefExpr *E) {
+ CXXScopeSpec SS = SemaRef.InstantiateScopeSpecifier(E->begin(), E->size(),
+ E->getQualifierRange(),
+ TemplateArgs,
+ NumTemplateArgs);
+ if (SS.isInvalid() || SS.isEmpty())
+ return SemaRef.ExprError();
+
+ // FIXME: We're passing in a NULL scope, because
+ // ActOnDeclarationNameExpr doesn't actually use the scope when we
+ // give it a non-empty scope specifier. Investigate whether it would
+ // be better to refactor ActOnDeclarationNameExpr.
+ return SemaRef.ActOnDeclarationNameExpr(/*Scope=*/0, E->getLocation(),
+ E->getDeclName(),
+ /*HasTrailingLParen=*/false,
+ &SS,
+ /*FIXME:isAddressOfOperand=*/false);
+}
+
+Sema::OwningExprResult
TemplateExprInstantiator::VisitCXXTemporaryObjectExpr(
CXXTemporaryObjectExpr *E) {
QualType T = E->getType();
@@ -1047,7 +1068,9 @@
// the best template.
ClassTemplateDecl *Template = ClassTemplateSpec->getSpecializedTemplate();
- if (!Template->getTemplatedDecl()->getDefinition(Context)) {
+ RecordDecl *Pattern = cast_or_null<RecordDecl>(
+ Template->getTemplatedDecl()->getDefinition(Context));
+ if (!Pattern) {
Diag(ClassTemplateSpec->getLocation(),
diag::err_template_implicit_instantiate_undefined)
<< Context.getTypeDeclType(ClassTemplateSpec);
@@ -1084,7 +1107,6 @@
// FIXME: Create the injected-class-name for the
// instantiation. Should this be a typedef or something like it?
- RecordDecl *Pattern = Template->getTemplatedDecl();
llvm::SmallVector<DeclTy *, 32> Fields;
for (RecordDecl::decl_iterator Member = Pattern->decls_begin(),
MemberEnd = Pattern->decls_end();
@@ -1118,3 +1140,34 @@
return Invalid;
}
+
+/// \brief Instantiate a sequence of nested-name-specifiers into a
+/// scope specifier.
+CXXScopeSpec
+Sema::InstantiateScopeSpecifier(const NestedNameSpecifier *Components,
+ unsigned NumComponents,
+ SourceRange Range,
+ const TemplateArgument *TemplateArgs,
+ unsigned NumTemplateArgs) {
+ CXXScopeSpec SS;
+ for (unsigned Comp = 0; Comp < NumComponents; ++Comp) {
+ if (Type *T = Components[Comp].getAsType()) {
+ QualType NewT = InstantiateType(QualType(T, 0), TemplateArgs,
+ NumTemplateArgs, Range.getBegin(),
+ DeclarationName());
+ if (NewT.isNull())
+ return SS;
+ NestedNameSpecifier NNS(NewT.getTypePtr());
+ SS.addScopeRep(NNS.getAsOpaquePtr());
+ } else {
+ DeclContext *DC = Components[Comp].getAsDeclContext();
+ // FIXME: injected-class-name might be dependent, and therefore
+ // would need instantiation.
+ NestedNameSpecifier NNS(DC);
+ SS.addScopeRep(NNS.getAsOpaquePtr());
+ }
+ }
+
+ SS.setRange(Range);
+ return SS;
+}