Consider this source:
extern char *index(const char *,int);
static int index;
"index" is a builtin as well, but because it's a builtin gcc skips the
"previous declaration was here..." despite having *a* previous decl it
could complain about. Note that newlib provides decls for many
builtins (the decl above is from newlib), so this could be a common
case.
So I added a check for !C_DECL_DECLARED_BUILTIN (decl) which seems to
specifically cover this case. Ok to apply?
* c-decl.c (locate_old_decl): If a previous conflicting decl is
both explicit and builtin, print the location of the explicit one.
Index: c-decl.c
===================================================================
--- c-decl.c (revision 204300)
+++ c-decl.c (working copy)
@@ -1630,13 +1630,14 @@ validate_proto_after_old_defn (tree newd
/* Subroutine of diagnose_mismatched_decls. Report the location of DECL,
first in a pair of mismatched declarations, using the diagnostic
function DIAG. */
static void
locate_old_decl (tree decl)
{
- if (TREE_CODE (decl) == FUNCTION_DECL && DECL_BUILT_IN (decl))
+ if (TREE_CODE (decl) == FUNCTION_DECL && DECL_BUILT_IN (decl)
+ && !C_DECL_DECLARED_BUILTIN (decl))
;
else if (DECL_INITIAL (decl))
inform (input_location, "previous definition of %q+D was here", decl);
else if (C_DECL_IMPLICIT (decl))
inform (input_location, "previous implicit declaration of %q+D was here",
decl);
else
