Re: [PATCH] PR66870 PowerPC64 Enable gold linker with split stack

["Lynn A. Boger" <laboger@linux.vnet.ibm.com>]

Thanks for doing this Alan.  I agree this looks better to me.

I assume by "etc" you mean you did biarch builds for your bootstraps on BE?

On 10/11/2015 08:07 AM, Alan Modra wrote:
> On Sat, Oct 10, 2015 at 11:25:38PM +0200, Andreas Schwab wrote:
>> "Lynn A. Boger" <laboger@linux.vnet.ibm.com> writes:
>>
>>> Index: gcc/config/rs6000/sysv4.h
>>> ===================================================================
>>> --- gcc/config/rs6000/sysv4.h	(revision 228653)
>>> +++ gcc/config/rs6000/sysv4.h	(working copy)
>>> @@ -940,13 +940,15 @@ ncrtn.o%s"
>>>   #undef TARGET_ASAN_SHADOW_OFFSET
>>>   #define TARGET_ASAN_SHADOW_OFFSET rs6000_asan_shadow_offset
>>>   
>>> -/* On ppc64 and ppc64le, split stack is only support for
>>> -   64 bit. */
>>> +/* On ppc64 and ppc64le, split stack is only supported for
>>> +   64 bit targets with a 64 bit compiler. */
>>>   #undef TARGET_CAN_SPLIT_STACK_64BIT
>>> +#if defined (__64BIT__) || defined (__powerpc64__) || defined (__ppc64__)
>> This doesn't make sense.  A target header cannot use host defines.
> Right.  Here's a better fix.  A powerpc-linux biarch compiler can
> default to either -m32 or -m64 so we need to take that into account,
> and notice both -m32 and -m64 on the gccgo command line.  It's also
> possible to build a -m64 only compiler, so in that case we can define
> TARGET_CAN_SPLIT_STACK.
>
> Bootstrapped etc. powerpc64-linux, powerpc-linux and
> powerpc64le-linux.  OK?
>
> gcc/
> 	* config/rs6000/sysv4.h (TARGET_CAN_SPLIT_STACK_64BIT): Don't define.
> 	* config/rs6000/linux64.h (TARGET_CAN_SPLIT_STACK): Define.
> 	(TARGET_CAN_SPLIT_STACK_64BIT): Define.
> gcc/go/
> 	* gospec.c (saw_opt_m32): Rename to..
> 	(is_m64): ..this, initialised by TARGET_CAN_SPLIT_STACK_64BIT.
> 	Update uses.
> 	(lang_specific_driver): Set is_m64 if OPT_m64, clear if OPT_m32.
>
> diff --git a/gcc/config/rs6000/sysv4.h b/gcc/config/rs6000/sysv4.h
> index 7b2f9bd..f48af43 100644
> --- a/gcc/config/rs6000/sysv4.h
> +++ b/gcc/config/rs6000/sysv4.h
> @@ -940,14 +940,6 @@ ncrtn.o%s"
>   #undef TARGET_ASAN_SHADOW_OFFSET
>   #define TARGET_ASAN_SHADOW_OFFSET rs6000_asan_shadow_offset
>
> -/* On ppc64 and ppc64le, split stack is only support for
> -   64 bit. */
> -#undef TARGET_CAN_SPLIT_STACK_64BIT
> -#if TARGET_GLIBC_MAJOR > 2 \
> -  || (TARGET_GLIBC_MAJOR == 2 && TARGET_GLIBC_MINOR >= 18)
> -#define TARGET_CAN_SPLIT_STACK_64BIT
> -#endif
> -
>   /* This target uses the sysv4.opt file.  */
>   #define TARGET_USES_SYSV4_OPT 1
>
> diff --git a/gcc/config/rs6000/linux64.h b/gcc/config/rs6000/linux64.h
> index 9599735..28c83e41 100644
> --- a/gcc/config/rs6000/linux64.h
> +++ b/gcc/config/rs6000/linux64.h
> @@ -245,6 +245,21 @@ extern int dot_symbols;
>   #define MULTILIB_DEFAULTS { "m32" }
>   #endif
>
> +/* Split stack is only supported for 64 bit, and requires glibc >= 2.18.  */
> +#if TARGET_GLIBC_MAJOR * 1000 + TARGET_GLIBC_MINOR >= 2018
> +# ifndef RS6000_BI_ARCH
> +#  define TARGET_CAN_SPLIT_STACK
> +# else
> +#  if DEFAULT_ARCH64_P
> +/* Supported, and the default is -m64  */
> +#   define TARGET_CAN_SPLIT_STACK_64BIT 1
> +#  else
> +/* Supported, and the default is -m32  */
> +#   define TARGET_CAN_SPLIT_STACK_64BIT 0
> +#  endif
> +# endif
> +#endif
> +
>   #ifndef RS6000_BI_ARCH
>
>   /* 64-bit PowerPC Linux always has a TOC.  */
> diff --git a/gcc/go/gospec.c b/gcc/go/gospec.c
> index ca3c2d7..fbb55be 100644
> --- a/gcc/go/gospec.c
> +++ b/gcc/go/gospec.c
> @@ -120,8 +120,10 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
>     /* Whether the -S option was used.  */
>     bool saw_opt_S = false;
>
> -  /* Whether the -m32 option was used. */
> -  bool saw_opt_m32 ATTRIBUTE_UNUSED = false;
> +#ifdef TARGET_CAN_SPLIT_STACK_64BIT
> +  /* Whether the -m64 option is in force. */
> +  bool is_m64 = TARGET_CAN_SPLIT_STACK_64BIT;
> +#endif
>
>     /* The first input file with an extension of .go.  */
>     const char *first_go_file = NULL;
> @@ -160,7 +162,11 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
>
>   #ifdef TARGET_CAN_SPLIT_STACK_64BIT
>   	case OPT_m32:
> -	  saw_opt_m32 = true;
> +	  is_m64 = false;
> +	  break;
> +
> +	case OPT_m64:
> +	  is_m64 = true;
>   	  break;
>   #endif
>
> @@ -253,7 +259,7 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options,
>   #endif
>
>   #ifdef TARGET_CAN_SPLIT_STACK_64BIT
> -  if (!saw_opt_m32)
> +  if (is_m64)
>       supports_split_stack = 1;
>   #endif
>
>
>