On Wed, Apr 29, 2015 at 06:41:22PM +0200, Marek Polacek wrote: > On Tue, Apr 28, 2015 at 09:07:09PM -0600, Martin Sebor wrote: > > The error message in the test cases below isn't quite right. > > The type of the aggregates isn't undefined, it's incomplete. > > Looking at the function, I wonder if the first argument > > should be EXPR rather than than NULL_TREE? Alternatively, > > experimenting with other cases where GCC diagnoses invalid > > uses of incomplete type, I see that it issues: > > > > "invalid application of %qs to incomplete type %qT" > > > > which might work even better here since we could name the > > expression (va_arg). > > Yeah, I haven't concerned myself with the exact wording of the error > message much, and I agree it could be improved. But passing down the > EXPR would mean that the compiler outputs "'ap' has an incomplete type" > and that looks wrong as well. I think I'm going to apply the following > tomorrow if I hear no objections (and it passes testing). Thanks for > noticing.
Committed now. > (And I think c_incomplete_type_error deserves some TLC; I'll post a separate > patch.) > > 2015-04-29 Marek Polacek <pola...@redhat.com> > > * c-typeck.c (c_build_va_arg): Clarify the error message. > > * gcc.dg/pr65901.c (foo): Adjust dg-error. > > diff --git gcc/c/c-typeck.c gcc/c/c-typeck.c > index c58e918..028d2f81 100644 > --- gcc/c/c-typeck.c > +++ gcc/c/c-typeck.c > @@ -12645,14 +12645,17 @@ c_build_qualified_type (tree type, int type_quals) > tree > c_build_va_arg (location_t loc, tree expr, tree type) > { > - if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE) > - warning_at (loc, OPT_Wc___compat, > - "C++ requires promoted type, not enum type, in %<va_arg%>"); > - if (type == error_mark_node || !COMPLETE_TYPE_P (type)) > + if (error_operand_p (type)) > + return error_mark_node; > + else if (!COMPLETE_TYPE_P (type)) > { > - c_incomplete_type_error (NULL_TREE, type); > + error_at (loc, "second argument to %<va_arg%> is of incomplete " > + "type %qT", type); > return error_mark_node; > } > + else if (warn_cxx_compat && TREE_CODE (type) == ENUMERAL_TYPE) > + warning_at (loc, OPT_Wc___compat, > + "C++ requires promoted type, not enum type, in %<va_arg%>"); > return build_va_arg (loc, expr, type); > } > > diff --git gcc/testsuite/gcc.dg/pr65901.c gcc/testsuite/gcc.dg/pr65901.c > index 8708a1e..b40eea3 100644 > --- gcc/testsuite/gcc.dg/pr65901.c > +++ gcc/testsuite/gcc.dg/pr65901.c > @@ -9,8 +9,8 @@ union U; > void > foo (__builtin_va_list ap) > { > - __builtin_va_arg (ap, void); /* { dg-error "invalid use of void > expression" } */ > - __builtin_va_arg (ap, struct S); /* { dg-error "invalid use of undefined > type" } */ > - __builtin_va_arg (ap, enum E); /* { dg-error "invalid use of undefined > type" } */ > - __builtin_va_arg (ap, union U); /* { dg-error "invalid use of undefined > type" } */ > + __builtin_va_arg (ap, void); /* { dg-error "second argument to .va_arg. > is of incomplete type .void." } */ > + __builtin_va_arg (ap, struct S); /* { dg-error "second argument to > .va_arg. is of incomplete type .struct S." } */ > + __builtin_va_arg (ap, enum E); /* { dg-error "second argument to .va_arg. > is of incomplete type .enum E." } */ > + __builtin_va_arg (ap, union U); /* { dg-error "second argument to > .va_arg. is of incomplete type .union U." } */ > } Marek