Simplify, and improve the performance of, template instantiation for
declaration references. The key realization is that dependent Decls,
which actually require instantiation, can only refer to the current
instantiation or members thereof. And, since the current context
during instantiation contains all of those members of the current
instantiation, we can simply find the real instantiate that matches up
with the "current instantiation" template.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72486 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/Sema.h b/lib/Sema/Sema.h
index 5b3ea40..3825b7c 100644
--- a/lib/Sema/Sema.h
+++ b/lib/Sema/Sema.h
@@ -2250,8 +2250,7 @@
FunctionDecl *Function);
void InstantiateVariableDefinition(VarDecl *Var);
- NamedDecl *
- InstantiateDeclRef(NamedDecl *D, const TemplateArgumentList &TemplateArgs);
+ NamedDecl *InstantiateCurrentDeclRef(NamedDecl *D);
// Simple function for cloning expressions.
template<typename T>
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 1cc9992..1546e39 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -407,8 +407,8 @@
TemplateTypeInstantiator::InstantiateTypedefType(const TypedefType *T,
unsigned Quals) const {
TypedefDecl *Typedef
- = cast_or_null<TypedefDecl>(SemaRef.InstantiateDeclRef(T->getDecl(),
- TemplateArgs));
+ = cast_or_null<TypedefDecl>(
+ SemaRef.InstantiateCurrentDeclRef(T->getDecl()));
if (!Typedef)
return QualType();
@@ -440,8 +440,7 @@
TemplateTypeInstantiator::InstantiateRecordType(const RecordType *T,
unsigned Quals) const {
RecordDecl *Record
- = cast_or_null<RecordDecl>(SemaRef.InstantiateDeclRef(T->getDecl(),
- TemplateArgs));
+ = cast_or_null<RecordDecl>(SemaRef.InstantiateCurrentDeclRef(T->getDecl()));
if (!Record)
return QualType();
@@ -452,8 +451,7 @@
TemplateTypeInstantiator::InstantiateEnumType(const EnumType *T,
unsigned Quals) const {
EnumDecl *Enum
- = cast_or_null<EnumDecl>(SemaRef.InstantiateDeclRef(T->getDecl(),
- TemplateArgs));
+ = cast_or_null<EnumDecl>(SemaRef.InstantiateCurrentDeclRef(T->getDecl()));
if (!Enum)
return QualType();
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index 41c1944..33eedce 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -671,8 +671,8 @@
return 0;
}
-/// \brief Find the instantiation of the given declaration with the
-/// given template arguments.
+/// \brief Find the instantiation of the given declaration within the
+/// current instantiation.
///
/// This routine is intended to be used when \p D is a declaration
/// referenced from within a template, that needs to mapped into the
@@ -695,10 +695,9 @@
/// In the instantiation of X<int>::getKind(), we need to map the
/// EnumConstantDecl for KnownValue (which refers to
/// X<T>::<Kind>::KnownValue) to its instantiation
-/// (X<int>::<Kind>::KnownValue). InstantiateDeclRef() performs this
-/// mapping, given the template arguments 'int'.
-NamedDecl *
-Sema::InstantiateDeclRef(NamedDecl *D, const TemplateArgumentList &TemplateArgs) {
+/// (X<int>::<Kind>::KnownValue). InstantiateCurrentDeclRef() performs
+/// this mapping from within the instantiation of X<int>.
+NamedDecl * Sema::InstantiateCurrentDeclRef(NamedDecl *D) {
DeclContext *ParentDC = D->getDeclContext();
if (isa<ParmVarDecl>(D) || ParentDC->isFunctionOrMethod()) {
// D is a local of some kind. Look into the map of local
@@ -707,7 +706,7 @@
}
if (NamedDecl *ParentDecl = dyn_cast<NamedDecl>(ParentDC)) {
- ParentDecl = InstantiateDeclRef(ParentDecl, TemplateArgs);
+ ParentDecl = InstantiateCurrentDeclRef(ParentDecl);
if (!ParentDecl)
return 0;
@@ -740,20 +739,27 @@
D = Result;
}
- // D itself might be a class template that we need to instantiate
- // with the given template arguments.
if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
- if (ClassTemplateDecl *ClassTemplate = Record->getDescribedClassTemplate()) {
- QualType InjectedClassName
- = ClassTemplate->getInjectedClassNameType(Context);
- QualType InstantiatedType = InstantiateType(InjectedClassName,
- TemplateArgs,
- Record->getLocation(),
- Record->getDeclName());
- if (InstantiatedType.isNull())
- return 0;
- if (const RecordType *RT = InstantiatedType->getAsRecordType())
- D = RT->getDecl();
+ if (ClassTemplateDecl *ClassTemplate
+ = Record->getDescribedClassTemplate()) {
+ // When the declaration D was parsed, it referred to the current
+ // instantiation. Therefore, look through the current context,
+ // which contains actual instantiations, to find the
+ // instantiation of the "current instantiation" that D refers
+ // to. Alternatively, we could just instantiate the
+ // injected-class-name with the current template arguments, but
+ // such an instantiation is far more expensive.
+ for (DeclContext *DC = CurContext; !DC->isFileContext();
+ DC = DC->getParent()) {
+ if (ClassTemplateSpecializationDecl *Spec
+ = dyn_cast<ClassTemplateSpecializationDecl>(DC))
+ if (Context.getCanonicalDecl(Spec->getSpecializedTemplate())
+ == Context.getCanonicalDecl(ClassTemplate))
+ return Spec;
+ }
+
+ assert(false &&
+ "Unable to find declaration for the current instantiation");
}
return D;
diff --git a/lib/Sema/SemaTemplateInstantiateExpr.cpp b/lib/Sema/SemaTemplateInstantiateExpr.cpp
index 726ac2b..31bb91d 100644
--- a/lib/Sema/SemaTemplateInstantiateExpr.cpp
+++ b/lib/Sema/SemaTemplateInstantiateExpr.cpp
@@ -108,7 +108,6 @@
Sema::OwningExprResult
TemplateExprInstantiator::VisitDeclRefExpr(DeclRefExpr *E) {
- // FIXME: Recast this in terms of Sema::InstantiateDeclRef.
NamedDecl *D = E->getDecl();
if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D)) {
assert(NTTP->getDepth() == 0 && "No nested templates yet");
@@ -141,7 +140,7 @@
}
ValueDecl *NewD
- = dyn_cast_or_null<ValueDecl>(SemaRef.InstantiateDeclRef(D, TemplateArgs));
+ = dyn_cast_or_null<ValueDecl>(SemaRef.InstantiateCurrentDeclRef(D));
if (!NewD)
return SemaRef.ExprError();