[google 4_7] fix unsat for target w/o atomic builtins

[xur, 2013-01-03 00:58:08]

Hi,

This patch fixes an issue in r194725. The call to atmoic builtin
is emmitted regardless of -fprofile-gen-atomic -- which results
in link unsat for targets without sync builtin support.

Tested with regression test in x86 (with builtin support.) 
and powerpc32 (without builtin support).

Thanks,

-Rong

2013-01-02  Rong Xu  <xur@google.com>

	* gcc/gcov-io.h: Make __atomic_fetch_add weak for these
        target without sync builtin support.

Index: gcc/gcov-io.h
===================================================================
--- gcc/gcov-io.h	(revision 194739)
+++ gcc/gcov-io.h	(working copy)
@@ -308,6 +308,10 @@ typedef unsigned gcov_type_unsigned __attribute__
 #define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_4
 #define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_4
 #endif
+/* Make the atomic builtin weak. Otherwise we get link unsat 
+   if the builtin is not available.  */
+extern gcov_type GCOV_TYPE_ATOMIC_FETCH_ADD_FN
+  (gcov_type*, gcov_type, int) __attribute__ ((weak));
 
 #undef EXTRACT_MODULE_ID_FROM_GLOBAL_ID
 #undef EXTRACT_FUNC_ID_FROM_GLOBAL_ID

--
This patch is available for review at http://codereview.appspot.com/7031051

[davidxl, 2013-01-03 01:10:28]

Ok for google branch, but it might be better to warn this at compile
time (more discussion needed for the trunk version).

David

On Wed, Jan 2, 2013 at 4:58 PM, Rong Xu <xur@google.com> wrote:
> Hi,
>
> This patch fixes an issue in r194725. The call to atmoic builtin
> is emmitted regardless of -fprofile-gen-atomic -- which results
> in link unsat for targets without sync builtin support.
>
> Tested with regression test in x86 (with builtin support.)
> and powerpc32 (without builtin support).
>
> Thanks,
>
> -Rong
>
> 2013-01-02  Rong Xu  <xur@google.com>
>
>         * gcc/gcov-io.h: Make __atomic_fetch_add weak for these
>         target without sync builtin support.
>
> Index: gcc/gcov-io.h
> ===================================================================
> --- gcc/gcov-io.h       (revision 194739)
> +++ gcc/gcov-io.h       (working copy)
> @@ -308,6 +308,10 @@ typedef unsigned gcov_type_unsigned __attribute__
>  #define GCOV_TYPE_ATOMIC_FETCH_ADD_FN __atomic_fetch_add_4
>  #define GCOV_TYPE_ATOMIC_FETCH_ADD BUILT_IN_ATOMIC_FETCH_ADD_4
>  #endif
> +/* Make the atomic builtin weak. Otherwise we get link unsat
> +   if the builtin is not available.  */
> +extern gcov_type GCOV_TYPE_ATOMIC_FETCH_ADD_FN
> +  (gcov_type*, gcov_type, int) __attribute__ ((weak));
>
>  #undef EXTRACT_MODULE_ID_FROM_GLOBAL_ID
>  #undef EXTRACT_FUNC_ID_FROM_GLOBAL_ID
>
> --
> This patch is available for review at http://codereview.appspot.com/7031051