Re: PATCH: Add Linux/x32 support to Ada

[Eric Botcazou <ebotcazou at adacore dot com>]

> This patch adds Linux/x32 support to Ada.  It sets LIBGNAT_TARGET_PAIRS
> similar to Linux/x86-64 and replaces system-linux-x86_64.ads with
> system-linux-x86.ads.  It also adds "orl $0x0,(%esp)" check for SIGSEGV
> probe and sets __gnat_default_libgcc_subdir to libx32 for x32.  Tested
> on Linux/x32 with the following Ada test failures:
>
> FAIL: gnat.dg/curr_task.adb execution test
> FAIL: gnat.dg/lto8.adb (test for excess errors)
> FAIL: gnat.dg/requeue1.adb execution test
> FAIL: gnat.dg/test_image.adb execution test
> FAIL: gnat.dg/timer_cancel.adb execution test
> FAIL: gnat.dg/specs/addr1.ads  (test for bogus messages, line 24)
> FAIL: gnat.dg/specs/addr1.ads (test for excess errors)
> FAIL: gnat.dg/specs/atomic1.ads  (test for errors, line 9)
> FAIL: gnat.dg/specs/atomic1.ads  (test for errors, line 13)

Thanks for working on this.

> 2012-03-02  H.J. Lu  <hongjiu.lu@intel.com>
>
> 	* init.c (__gnat_adjust_context_for_raise): Also check
> 	"orq $0x0,(%esp)" for x32.
>
> 	* link.c (__gnat_default_libgcc_subdir): set to libx32 for x32.
>
> 	* gcc-interface/Makefile.in (arch): Set to x32 if MULTISUBDIR
> 	is /x32.
> 	Support x32.

This looks good to me, modulo the following nits:

> --- a/gcc/ada/init.c
> +++ b/gcc/ada/init.c
> @@ -615,9 +615,16 @@ __gnat_adjust_context_for_raise (int signo
> ATTRIBUTE_UNUSED, void *ucontext) if (signo == SIGSEGV && pc && *pc ==
> 0x00240c83)
>      mcontext->gregs[REG_ESP] += 4096 + 4 * sizeof (unsigned long);
>  #elif defined (__x86_64__)
> -  unsigned long *pc = (unsigned long *)mcontext->gregs[REG_RIP];
> -  /* The pattern is "orq $0x0,(%rsp)" for a probe in 64-bit mode.  */
> -  if (signo == SIGSEGV && pc && (*pc & 0xffffffffff) == 0x00240c8348)
> +  unsigned long long *pc = (unsigned long long *)mcontext->gregs[REG_RIP];
> +  if (signo == SIGSEGV && pc
> +      /* The pattern is "orq $0x0,(%rsp)" for a probe in 64-bit mode.  */
> +      && ((*pc & 0xffffffffffLL) == 0x00240c8348LL
> +# ifndef __LP64__
> +      /* The pattern may also be "orl $0x0,(%esp)" for a probe in x32
> +	 mode.  */
> +	  || (*pc & 0xffffffffLL) == 0x00240c83LL
> +# endif
> +	 ))
>      mcontext->gregs[REG_RSP] += 4096 + 4 * sizeof (unsigned long);
>  #elif defined (__ia64__)
>    /* ??? The IA-64 unwinder doesn't compensate for signals.  */

The preprocessor directive is very likely superfluous, let's remove it and just 
add the || thing.

> diff --git a/gcc/ada/link.c b/gcc/ada/link.c
> index 8bcad27..3648878 100644
> --- a/gcc/ada/link.c
> +++ b/gcc/ada/link.c
> @@ -187,7 +187,11 @@ unsigned char __gnat_using_gnu_linker = 1;
>  const char *__gnat_object_library_extension = ".a";
>  unsigned char __gnat_separate_run_path_options = 0;
>  #if defined (__x86_64)
> +# if defined __LP64__
>  const char *__gnat_default_libgcc_subdir = "lib64";
> +# else
> +const char *__gnat_default_libgcc_subdir = "libx32";
> +# endif
>  #else
>  const char *__gnat_default_libgcc_subdir = "lib";
>  #endif

Please follow the existing idiom and write defined (__LP64__) instead.

OK with these changes.

-- 
Eric Botcazou