Re: [PING, PATCH] libitm: Introduce target macro TARGET_BEGIN_TRANSACTION_ATTRIBUTE.

[Dominik Vogt <vogt at linux dot vnet dot ibm dot com>]

On Mon, Feb 01, 2016 at 02:18:48PM +0100, Dominik Vogt wrote:
> The attached patch adds the a target specific attribute via the
> new target macro TARGET_BEGIN_TRANSACTION_ATTRIBUTE to the
> function begin_transaction().  S/390 uses this to set the
> soft-float target attribute which is needed to fix a crash with
> -m31.
> 
> As there seems to be no place in libitm to document internal macros like
> USE_HTM_FASTPATH or the new macro, I've put the documentation in a
> comment where the macro is used.

Please note that we're waiting for approval of the libitm
maintainer, not for approval of the s390 maintainer.

> libitm/ChangeLog
> 
> 	* config/s390/target.h (TARGET_BEGIN_TRANSACTION_ATTRIBUTE): Define
> 	function attribute to disable floating point in begin_transaction() on
> 	S/390.
> 	* beginend.cc (begin_transaction): Use
> 	TARGET_BEGIN_TRANSACTION_ATTRIBUTE.

> >From a5c8087753ab1f42082b9ab44d443005ed2c53ba Mon Sep 17 00:00:00 2001
> From: Dominik Vogt <vogt@linux.vnet.ibm.com>
> Date: Mon, 1 Feb 2016 14:07:55 +0100
> Subject: [PATCH] libitm: Introduce target macro
>  TARGET_BEGIN_TRANSACTION_ATTRIBUTE.
> 
> The macro can be used to add attributes to the function begin_transaction.  Set
> it for S/390 to switch of harware floating point.
> ---
>  libitm/beginend.cc          | 6 ++++++
>  libitm/config/s390/target.h | 3 +++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/libitm/beginend.cc b/libitm/beginend.cc
> index 1a258ad..20b5547 100644
> --- a/libitm/beginend.cc
> +++ b/libitm/beginend.cc
> @@ -149,6 +149,12 @@ choose_code_path(uint32_t prop, abi_dispatch *disp)
>      return a_runInstrumentedCode;
>  }
>  
> +#ifdef TARGET_BEGIN_TRANSACTION_ATTRIBUTE
> +/* This macro can be used to define target specific attributes for this
> +   function.  For example, S/390 requires floating point to be disabled in
> +   begin_transaction.  */
> +TARGET_BEGIN_TRANSACTION_ATTRIBUTE
> +#endif
>  uint32_t
>  GTM::gtm_thread::begin_transaction (uint32_t prop, const gtm_jmpbuf *jb)
>  {
> diff --git a/libitm/config/s390/target.h b/libitm/config/s390/target.h
> index 44819a4..c9d5203 100644
> --- a/libitm/config/s390/target.h
> +++ b/libitm/config/s390/target.h
> @@ -69,6 +69,9 @@ cpu_relax (void)
>  /* Number of retries for transient failures.  */
>  #define _HTM_ITM_RETRIES 10
>  #define USE_HTM_FASTPATH
> +#define TARGET_BEGIN_TRANSACTION_ATTRIBUTE \
> +  __attribute__ ((target("soft-float")))
> +
>  
>  static inline bool
>  htm_available ()
> -- 
> 2.3.0
> 



Ciao

Dominik ^_^  ^_^

-- 

Dominik Vogt
IBM Germany