The attached patch improves our handling of value dependent expressions in
attribute((enable_if)), both in the condition expression and at the call
site. Fixes PR20988.
Please review!
Nick
Index: lib/AST/ExprConstant.cpp
===================================================================
--- lib/AST/ExprConstant.cpp (revision 223753)
+++ lib/AST/ExprConstant.cpp (working copy)
@@ -9072,7 +9072,8 @@
ArgVector ArgValues(Args.size());
for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
I != E; ++I) {
- if (!Evaluate(ArgValues[I - Args.begin()], Info, *I))
+ if ((*I)->isValueDependent() ||
+ !Evaluate(ArgValues[I - Args.begin()], Info, *I))
// If evaluation fails, throw away the argument entirely.
ArgValues[I - Args.begin()] = APValue();
if (Info.EvalStatus.HasSideEffects)
Index: lib/Sema/SemaOverload.cpp
===================================================================
--- lib/Sema/SemaOverload.cpp (revision 223753)
+++ lib/Sema/SemaOverload.cpp (working copy)
@@ -5789,6 +5789,7 @@
// Convert the arguments.
SmallVector<Expr *, 16> ConvertedArgs;
bool InitializationFailed = false;
+ bool ContainsValueDependentExpr = false;
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
if (i == 0 && !MissingImplicitThis && isa<CXXMethodDecl>(Function) &&
!cast<CXXMethodDecl>(Function)->isStatic() &&
@@ -5801,6 +5802,7 @@
InitializationFailed = true;
break;
}
+ ContainsValueDependentExpr |= R.get()->isValueDependent();
ConvertedArgs.push_back(R.get());
} else {
ExprResult R =
@@ -5813,6 +5815,7 @@
InitializationFailed = true;
break;
}
+ ContainsValueDependentExpr |= R.get()->isValueDependent();
ConvertedArgs.push_back(R.get());
}
}
@@ -5823,9 +5826,16 @@
for (AttrVec::iterator I = Attrs.begin(); I != E; ++I) {
APValue Result;
EnableIfAttr *EIA = cast<EnableIfAttr>(*I);
+ if (EIA->getCond()->isValueDependent()) {
+ // Don't even try now, we'll examine it after instantiation.
+ continue;
+ }
+
if (!EIA->getCond()->EvaluateWithSubstitution(
- Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)) ||
- !Result.isInt() || !Result.getInt().getBoolValue()) {
+ Result, Context, Function, llvm::makeArrayRef(ConvertedArgs))) {
+ if (!ContainsValueDependentExpr)
+ return EIA;
+ } else if (!Result.isInt() || !Result.getInt().getBoolValue()) {
return EIA;
}
}
Index: test/SemaCXX/enable_if.cpp
===================================================================
--- test/SemaCXX/enable_if.cpp (revision 223753)
+++ test/SemaCXX/enable_if.cpp (working copy)
@@ -77,3 +77,44 @@
typedep(1);
typedep(n); // expected-note{{in instantiation of function template specialization 'typedep<Nothing>' requested here}}
}
+
+template <typename T> class C {
+ void f() __attribute__((enable_if(T::expr == 0, ""))) {}
+ void g() { f(); }
+};
+
+int fn3(bool b) __attribute__((enable_if(b, "")));
+template <class T> void test3() {
+ fn3(sizeof(T) == 1);
+}
+
+// FIXME: issue an error (without instantiation) because h(T()) is not
+// convertible to bool, because return types aren't overloadable.
+void h(int);
+template <typename T> void outer() {
+ void local_function() __attribute__((enable_if(h(T()), "")));
+ local_function();
+};
+
+namespace PR20988 {
+ struct Integer {
+ Integer(int);
+ };
+
+ int fn1(const Integer &) __attribute__((enable_if(true, "")));
+ template <class T> void test1() {
+ int &expr = T::expr();
+ fn1(expr);
+ }
+
+ int fn2(const Integer &) __attribute__((enable_if(false, ""))); // expected-note{{candidate disabled}}
+ template <class T> void test2() {
+ int &expr = T::expr();
+ fn2(expr); // expected-error{{no matching function for call to 'fn2'}}
+ }
+
+ int fn3(bool b) __attribute__((enable_if(b, "")));
+ template <class T> void test3() {
+ fn3(sizeof(T) == 1);
+ }
+}
_______________________________________________
cfe-commits mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
