Hi!
We get bogus warning on the -1 and -4 testcases.
The problem is that we accept without warning an __asm rename like:
extern void *baz (void *dest, const void *src, __SIZE_TYPE__ n);
extern __typeof (baz) baz __asm("bazfn");
only if it doesn't have DECL_ASSEMBLER_NAME_SET_P yet, after it is
set we just warn and ignore the rename.
But for #pragma weak, if there are any pending #pragma weak pragmas,
we actually set DECL_ASSEMBLER_NAME right away.
Fixed by computing DECL_ASSEMBLER_NAME for the #pragma weak handling
just temporarily if it hasn't been set yet (yeah, it is duplicate work then,
but hopefully not very common), plus also fixing the early outs
- if a decl matching some #pragma weak is found, that vector entry is
removed from pending_weaks, but we were only testing if pending_weaks is
NULL, which it will never be after it has been allocated once.
Thus, for the most common case (well, most code doesn't use #pragma weak at
all) where you have #pragma weak followed by corresponding prototype or
say a couple of #pragma weak directives followed by corresponding
prototypes, there should be either no or just very small amount of extra
decl_assembler_name invocations.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2014-03-13 Jakub Jelinek <ja...@redhat.com>
PR middle-end/36282
* c-pragma.c (apply_pragma_weak): Only look at
TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)) if
DECL_ASSEMBLER_NAME_SET_P (decl).
(maybe_apply_pending_pragma_weaks): Exit early if
vec_safe_is_empty (pending_weaks) rather than only when
!pending_weaks.
(maybe_apply_pragma_weak): Likewise. If !DECL_ASSEMBLER_NAME_SET_P,
set assembler name back to NULL afterwards.
* c-c++-common/pr36282-1.c: New test.
* c-c++-common/pr36282-2.c: New test.
* c-c++-common/pr36282-3.c: New test.
* c-c++-common/pr36282-4.c: New test.
--- gcc/c-family/c-pragma.c.jj 2014-03-06 13:05:17.000000000 +0100
+++ gcc/c-family/c-pragma.c 2014-03-13 14:39:44.200586561 +0100
@@ -263,6 +263,7 @@ apply_pragma_weak (tree decl, tree value
if (SUPPORTS_WEAK && DECL_EXTERNAL (decl) && TREE_USED (decl)
&& !DECL_WEAK (decl) /* Don't complain about a redundant #pragma. */
+ && DECL_ASSEMBLER_NAME_SET_P (decl)
&& TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
warning (OPT_Wpragmas, "applying #pragma weak %q+D after first use "
"results in unspecified behavior", decl);
@@ -280,7 +281,7 @@ maybe_apply_pragma_weak (tree decl)
/* Avoid asking for DECL_ASSEMBLER_NAME when it's not needed. */
/* No weak symbols pending, take the short-cut. */
- if (!pending_weaks)
+ if (vec_safe_is_empty (pending_weaks))
return;
/* If it's not visible outside this file, it doesn't matter whether
it's weak. */
@@ -292,7 +293,13 @@ maybe_apply_pragma_weak (tree decl)
if (TREE_CODE (decl) != FUNCTION_DECL && TREE_CODE (decl) != VAR_DECL)
return;
- id = DECL_ASSEMBLER_NAME (decl);
+ if (DECL_ASSEMBLER_NAME_SET_P (decl))
+ id = DECL_ASSEMBLER_NAME (decl);
+ else
+ {
+ id = DECL_ASSEMBLER_NAME (decl);
+ SET_DECL_ASSEMBLER_NAME (decl, NULL_TREE);
+ }
FOR_EACH_VEC_ELT (*pending_weaks, i, pe)
if (id == pe->name)
@@ -313,7 +320,7 @@ maybe_apply_pending_pragma_weaks (void)
pending_weak *pe;
symtab_node *target;
- if (!pending_weaks)
+ if (vec_safe_is_empty (pending_weaks))
return;
FOR_EACH_VEC_ELT (*pending_weaks, i, pe)
--- gcc/testsuite/c-c++-common/pr36282-1.c.jj 2014-03-13 14:31:03.752580696
+0100
+++ gcc/testsuite/c-c++-common/pr36282-1.c 2014-03-13 14:31:56.110270219
+0100
@@ -0,0 +1,12 @@
+/* PR middle-end/36282 */
+/* { dg-do compile } */
+
+#pragma weak bar
+
+extern void *baz (void *dest, const void *src, __SIZE_TYPE__ n);
+extern __typeof (baz) baz __asm("bazfn"); /* { dg-bogus "asm declaration
ignored due to conflict with previous rename" } */
+
+void
+foo (void)
+{
+}
--- gcc/testsuite/c-c++-common/pr36282-2.c.jj 2014-03-13 14:31:03.752580696
+0100
+++ gcc/testsuite/c-c++-common/pr36282-2.c 2014-03-13 14:32:01.264247933
+0100
@@ -0,0 +1,10 @@
+/* PR middle-end/36282 */
+/* { dg-do compile } */
+
+extern void *baz (void *dest, const void *src, __SIZE_TYPE__ n);
+extern __typeof (baz) baz __asm("bazfn"); /* { dg-bogus "asm declaration
ignored due to conflict with previous rename" } */
+
+void
+foo (void)
+{
+}
--- gcc/testsuite/c-c++-common/pr36282-3.c.jj 2014-03-13 14:31:03.752580696
+0100
+++ gcc/testsuite/c-c++-common/pr36282-3.c 2014-03-13 14:32:07.243209260
+0100
@@ -0,0 +1,13 @@
+/* PR middle-end/36282 */
+/* { dg-do compile } */
+
+void bar (void);
+#pragma weak bar
+
+extern void *baz (void *dest, const void *src, __SIZE_TYPE__ n);
+extern __typeof (baz) baz __asm("bazfn"); /* { dg-bogus "asm declaration
ignored due to conflict with previous rename" } */
+
+void
+foo (void)
+{
+}
--- gcc/testsuite/c-c++-common/pr36282-4.c.jj 2014-03-13 14:31:03.752580696
+0100
+++ gcc/testsuite/c-c++-common/pr36282-4.c 2014-03-13 14:32:12.831177682
+0100
@@ -0,0 +1,13 @@
+/* PR middle-end/36282 */
+/* { dg-do compile } */
+
+#pragma weak bar
+void bar (void);
+
+extern void *baz (void *dest, const void *src, __SIZE_TYPE__ n);
+extern __typeof (baz) baz __asm("bazfn"); /* { dg-bogus "asm declaration
ignored due to conflict with previous rename" } */
+
+void
+foo (void)
+{
+}
Jakub
