From patchwork Wed Aug 18 21:07:55 2010
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Subject: [Ada] Change backtrace mechanism for x86/Linux
From: Eric Botcazou <ebotcazou@adacore.com>
X-Patchwork-Id: 62090
Message-Id: <201008182307.55337.ebotcazou@adacore.com>
To: gcc-patches@gcc.gnu.org
Date: Wed, 18 Aug 2010 23:07:55 +0200

This adjusts the backtrace mechanism used on x86/Linux to the default setting
of -fomit-frame-pointer on this platform.

Tested on i586-suse-linux, applied on the mainline.


2010-08-18  Eric Botcazou  <ebotcazou@adacore.com>

	* tracebak.c (i386): Use GCC unwinder on Linux with GCC > 4.5.


Index: tracebak.c
===================================================================
--- tracebak.c	(revision 163220)
+++ tracebak.c	(working copy)
@@ -303,7 +303,14 @@ struct layout
 #define IS_BAD_PTR(ptr) 0
 #endif
 
+/* Starting with GCC 4.6, -fomit-frame-pointer is turned on by default for
+   32-bit x86/Linux as well and DWARF 2 unwind tables are emitted instead.
+   See the x86-64 case below for the drawbacks with this approach.  */
+#if defined (linux) && (__GNUC__ * 10 + __GNUC_MINOR__ > 45)
+#define USE_GCC_UNWINDER
+#else
 #define USE_GENERIC_UNWINDER
+#endif
 
 struct layout
 {