ldionne added inline comments.
================ Comment at: clang/include/clang/Basic/DiagnosticSemaKinds.td:4683-4686 + "Member '%0' marked with 'exclude_from_explicit_instantiation' attribute is " + "not defined but an explicit template instantiation declaration exists. " + "Reliance on this member being defined by an explicit template instantiation " + "will lead to link errors.">; ---------------- rsmith wrote: > Diagnostics should start with a lowercase letter and not end with a period. > > That said, I'm not sure I see why this diagnostic is correct / useful. If the > entity is never used, then there's no link error. And if it is ever used, > then you should get an implicit instantiation like normal, and we already > have a diagnostic for the case where an entity is implicitly instantiated and > no definition is available. > Diagnostics should start with a lowercase letter and not end with a period. Done. > That said, I'm not sure I see why this diagnostic is correct / useful. If the > entity is never used, then there's no link error. And if it is ever used, > then you should get an implicit instantiation like normal, and we already > have a diagnostic for the case where an entity is implicitly instantiated and > no definition is available. This is not what happens right now. If you don't provide a definition but you try to call the function, an extern call will be produced (and that will result in a link error because any potential explicit instantiation won't provide the function). For example: ``` cat <<EOF | ./install/bin/clang++ -cc1 -stdlib=libc++ -xc++ -emit-llvm -o - - template <class T> struct Foo { __attribute__((exclude_from_explicit_instantiation)) static void static_member_function(); }; extern template struct Foo<int>; int main() { Foo<int>::static_member_function(); } EOF ``` Results in the following LLVM IR: ``` ; Function Attrs: noinline norecurse nounwind optnone define i32 @main() #0 { entry: call void @_ZN3FooIiE22static_member_functionEv() ret i32 0 } declare void @_ZN3FooIiE22static_member_functionEv() #1 ``` I guess we should be getting a warning or an error on the point of implicit instantiation instead, or is this behavior acceptable? ================ Comment at: clang/lib/Sema/SemaTemplateInstantiate.cpp:2581-2582 + if (Function->hasAttr<ExcludeFromExplicitInstantiationAttr>()) { + if (TSK == TSK_ExplicitInstantiationDeclaration && + !Pattern->isDefined()) { + Diag(Function->getLocation(), ---------------- rsmith wrote: > Nit: we prefer to left-align continuation lines (clang-format will do that > for you). Thanks for the heads up. I ran clang-format on all the lines I touched in this file. Repository: rC Clang https://reviews.llvm.org/D51789 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits