From patchwork Sat Oct  6 15:09:17 2012
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Subject: fix libbacktrace build failure on arm-linux
Date: Sat, 06 Oct 2012 05:09:17 -0000
From: Matthias Klose <doko@ubuntu.com>
X-Patchwork-Id: 189713
Message-Id: <5070499D.2060001@ubuntu.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>

current trunk fails to build on arm-linux with:

In file included from ../../../../src/libbacktrace/backtrace.c:35:0:
../libgcc/unwind.h: In function '_Unwind_decode_typeinfo_ptr':
../libgcc/unwind.h:42:45: error: unused parameter 'base' [-Werror=unused-parameter]
   _Unwind_decode_typeinfo_ptr (_Unwind_Word base, _Unwind_Word ptr)
                                             ^
../libgcc/unwind.h: In function '__gnu_unwind_24bit':
../libgcc/unwind.h:68:41: error: unused parameter 'context'
[-Werror=unused-parameter]
   __gnu_unwind_24bit (_Unwind_Context * context, _uw data, int compact)
                                         ^
../libgcc/unwind.h:68:54: error: unused parameter 'data' [-Werror=unused-parameter]
   __gnu_unwind_24bit (_Unwind_Context * context, _uw data, int compact)
                                                      ^
../libgcc/unwind.h:68:64: error: unused parameter 'compact'
[-Werror=unused-parameter]
   __gnu_unwind_24bit (_Unwind_Context * context, _uw data, int compact)
                                                                ^
cc1: all warnings being treated as errors
make[8]: *** [backtrace.lo] Error 1

the immediate fix is to mark all arguments as unused, however I don't know if
this function should be used by libbacktrace, if it returns _URC_FAILURE
unconditionally.

	* config/arm/unwind-arm.h (__gnu_unwind_24bit): Mark parameters
	as unused.


--- libgcc/config/arm/unwind-arm.h      (revision 192162)
+++ libgcc/config/arm/unwind-arm.h      (working copy)
@@ -64,8 +64,11 @@
       return tmp;
     }

+#define __unused __attribute__((unused))
+
   static inline _Unwind_Reason_Code
-  __gnu_unwind_24bit (_Unwind_Context * context, _uw data, int compact)
+  __gnu_unwind_24bit (_Unwind_Context * context __unused, _uw data __unused,
+                      int compact __unused)
     {
       return _URC_FAILURE;
     }