Re: [PATCH] Fix for PR libstdc++/60758

[Alexey Merzlyakov <alexey dot merzlyakov at samsung dot com>]

On 04.04.2014 14:44, Alexey Merzlyakov wrote:
> Hi all,
>
> Here is a patch, that fixes infinite backtraces in __cxa_end_cleanup().
> The Bugzilla entry for 
> this:http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60758
>
> The __cxa_end_cleanup() does not save/restore LR in function 
> header/footer and does not provide any unwind info,
> which causes problems with GDB and other tools (e.g. unwind code in 
> libgcc, libbacktrace, etc.).
>
> Best regards,
> Merzlyakov Alexey
>
> 2014-04-03  Alexey Merzlyakov <alexey.merzlyakov@samsung.com>
>
>     PR libstdc++/60758
>     * libsupc++/eh_arm.cc (__cxa_end_cleanup): Add LR save/restore.
>
> diff --git a/libstdc++-v3/libsupc++/eh_arm.cc 
> b/libstdc++-v3/libsupc++/eh_arm.cc
> index aa453dd..ead1e61 100644
> --- a/libstdc++-v3/libsupc++/eh_arm.cc
> +++ b/libstdc++-v3/libsupc++/eh_arm.cc
> @@ -206,9 +206,9 @@ asm ("  .pushsection .text.__cxa_end_cleanup\n"
>  "    .type __cxa_end_cleanup, \"function\"\n"
>  "    .thumb_func\n"
>  "__cxa_end_cleanup:\n"
> -"    push\t{r1, r2, r3, r4}\n"
> +"    push\t{r1, r2, r3, r4, lr}\n"
>  "    bl\t__gnu_end_cleanup\n"
> -"    pop\t{r1, r2, r3, r4}\n"
> +"    pop\t{r1, r2, r3, r4, lr}\n"
>  "    bl\t_Unwind_Resume @ Never returns\n"
>  "    .popsection\n");
>  #else
> @@ -216,9 +216,9 @@ asm ("  .pushsection .text.__cxa_end_cleanup\n"
>  "    .global __cxa_end_cleanup\n"
>  "    .type __cxa_end_cleanup, \"function\"\n"
>  "__cxa_end_cleanup:\n"
> -"    stmfd\tsp!, {r1, r2, r3, r4}\n"
> +"    stmfd\tsp!, {r1, r2, r3, r4, lr}\n"
>  "    bl\t__gnu_end_cleanup\n"
> -"    ldmfd\tsp!, {r1, r2, r3, r4}\n"
> +"    ldmfd\tsp!, {r1, r2, r3, r4, lr}\n"
>  "    bl\t_Unwind_Resume @ Never returns\n"
>  "    .popsection\n");
>  #endif

Forgot to mention:
the patch has been tested on ARM - no regressions.

Best regards,
Merzlyakov Alexey