Introduce the notion of instantiation dependence into Clang's AST. A
type/expression/template argument/etc. is instantiation-dependent if
it somehow involves a template parameter, even if it doesn't meet the
requirements for the more common kinds of dependence (dependent type,
type-dependent expression, value-dependent expression).
When we see an instantiation-dependent type, we know we always need to
perform substitution into that instantiation-dependent type. This
keeps us from short-circuiting evaluation in places where we
shouldn't, and lets us properly implement C++0x [temp.type]p2.
In theory, this would also allow us to properly mangle
instantiation-dependent-but-not-dependent decltype types per the
Itanium C++ ABI, but we aren't quite there because we still mangle
based on the canonical type in cases like, e.g.,
template<unsigned> struct A { };
template<typename T>
void f(A<sizeof(sizeof(decltype(T() + T())))>) { }
template void f<int>(A<sizeof(sizeof(int))>);
and therefore get the wrong answer.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134225 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/TemplateBase.cpp b/lib/AST/TemplateBase.cpp
index 103da1d..56c6e7b 100644
--- a/lib/AST/TemplateBase.cpp
+++ b/lib/AST/TemplateBase.cpp
@@ -104,6 +104,45 @@
return false;
}
+bool TemplateArgument::isInstantiationDependent() const {
+ switch (getKind()) {
+ case Null:
+ assert(false && "Should not have a NULL template argument");
+ return false;
+
+ case Type:
+ return getAsType()->isInstantiationDependentType();
+
+ case Template:
+ return getAsTemplate().isInstantiationDependent();
+
+ case TemplateExpansion:
+ return true;
+
+ case Declaration:
+ if (DeclContext *DC = dyn_cast<DeclContext>(getAsDecl()))
+ return DC->isDependentContext();
+ return getAsDecl()->getDeclContext()->isDependentContext();
+
+ case Integral:
+ // Never dependent
+ return false;
+
+ case Expression:
+ return getAsExpr()->isInstantiationDependent();
+
+ case Pack:
+ for (pack_iterator P = pack_begin(), PEnd = pack_end(); P != PEnd; ++P) {
+ if (P->isInstantiationDependent())
+ return true;
+ }
+
+ return false;
+ }
+
+ return false;
+}
+
bool TemplateArgument::isPackExpansion() const {
switch (getKind()) {
case Null: