+2011-01-24 Jan Hubicka <jh@suse.cz>
+
+ PR c/21659
+ * doc/extend.texi (weak pragma): Drop claim that it must
+ appear before definition.
+ * varasm.c (merge_weak, declare_weak): Only sanity check
+ that DECL is not output at a time it is declared weak.
+
2011-01-24 Kenneth Zadeck <zadeck@naturalbridge.com>
* machmode.def: Fixed comments.
@cindex pragma, weak
This pragma declares @var{symbol} to be weak, as if the declaration
had the attribute of the same name. The pragma may appear before
-or after the declaration of @var{symbol}, but must appear before
-either its first use or its definition. It is not an error for
+or after the declaration of @var{symbol}. It is not an error for
@var{symbol} to never be defined at all.
@item #pragma weak @var{symbol1} = @var{symbol2}
/* NEWDECL is weak, but OLDDECL is not. */
/* If we already output the OLDDECL, we're in trouble; we can't
- go back and make it weak. This error cannot be caught in
- declare_weak because the NEWDECL and OLDDECL was not yet
- been merged; therefore, TREE_ASM_WRITTEN was not set. */
- if (TREE_ASM_WRITTEN (olddecl))
- error ("weak declaration of %q+D must precede definition",
- newdecl);
+ go back and make it weak. This should never happen in
+ unit-at-a-time compilation. */
+ gcc_assert (!TREE_ASM_WRITTEN (olddecl));
/* If we've already generated rtl referencing OLDDECL, we may
have done so in a way that will not function properly with
- a weak symbol. */
- else if (TREE_USED (olddecl)
- && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (olddecl)))
- warning (0, "weak declaration of %q+D after first use results "
- "in unspecified behavior", newdecl);
+ a weak symbol. Again in unit-at-a-time this should be
+ impossible. */
+ gcc_assert (!TREE_USED (olddecl)
+ || !TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (olddecl)));
if (TARGET_SUPPORTS_WEAK)
{
void
declare_weak (tree decl)
{
+ gcc_assert (TREE_CODE (decl) != FUNCTION_DECL || !TREE_ASM_WRITTEN (decl));
if (! TREE_PUBLIC (decl))
error ("weak declaration of %q+D must be public", decl);
- else if (TREE_CODE (decl) == FUNCTION_DECL && TREE_ASM_WRITTEN (decl))
- error ("weak declaration of %q+D must precede definition", decl);
else if (!TARGET_SUPPORTS_WEAK)
warning (0, "weak declaration of %q+D not supported", decl);