[PATCH][GCC][ARM] Implement "arch" GCC pragma and "+<ext>" attributes [Patch (2/3)]

[Kyrill Tkachov]

On 15/11/17 15:59, Tamar Christina wrote:
>
>> -----Original Message-----
>> From: Kyrill Tkachov [mailto:kyrylo.tkachov@foss.arm.com]
>> Sent: Wednesday, November 15, 2017 10:11
>> To: Tamar Christina <Tamar.Christina@arm.com>; Sandra Loosemore
>> <sandra@codesourcery.com>; gcc-patches@gcc.gnu.org
>> Cc: nd <nd@arm.com>; Ramana Radhakrishnan
>> <Ramana.Radhakrishnan@arm.com>; Richard Earnshaw
>> <Richard.Earnshaw@arm.com>; nickc@redhat.com
>> Subject: Re: [PATCH][GCC][ARM] Implement "arch" GCC pragma and
>> "+<ext>" attributes [Patch (2/3)]
>>
>> Hi Tamar,
>>
>> On 10/11/17 10:56, Tamar Christina wrote:
>>> Hi Sandra,
>>>
>>> I've respun the patch with the docs changes you requested.
>>>
>>> Regards,
>>> Tamar
>>>
>>>> -----Original Message-----
>>>> From: Sandra Loosemore [mailto:sandra@codesourcery.com]
>>>> Sent: 07 November 2017 03:38
>>>> To: Tamar Christina; gcc-patches@gcc.gnu.org
>>>> Cc: nd; Ramana Radhakrishnan; Richard Earnshaw; nickc@redhat.com;
>>>> Kyrylo Tkachov
>>>> Subject: Re: [PATCH][GCC][ARM] Implement "arch" GCC pragma and
>>>> "+<ext>" attributes [Patch (2/3)]
>>>>
>>>> On 11/06/2017 09:50 AM, Tamar Christina wrote:
>>>>> Hi All,
>>>>>
>>>>> This patch adds support for the setting the architecture and
>>>>> extensions using the target GCC pragma.
>>>>>
>>>>> #pragma GCC target ("arch=armv8-a+crc")
>>>>>
>>>>> It also supports a short hand where an extension is just added to
>>>>> the current architecture without changing it
>>>>>
>>>>> #pragma GCC target ("+crc")
>>>>>
>>>>> Popping and pushing options also correctly reconfigure the global
>>>>> state as expected.
>>>>>
>>>>> Also supported is using the __attribute__((target("...")))
>>>>> attributes on functions to change the architecture or extension.
>>>>>
>>>>> Regtested on arm-none-eabi and no regressions.
>> This will need a bootstrap and test run on arm-none-linux-gnueabihf (like all
>> arm changes).
>> Your changelog at
>> https://gcc.gnu.org/ml/gcc-patches/2017-11/msg00387.html mentions some
>> arm-c.c changes but I don't see any included in this patch?
>>
>> The other changes look good and in line with what I would expect, but can
>> you please post the arm-c.c changes if there are any?
> Hi Kyrill,
>
> Sorry, I moved this change into another patch that was already committed and forgot
> to remove it from this changelog.
>
> I've also already bootstrapped this and the 3rd patch when you asked for the bootstrap of
> First one.  But I didn't update mail the status to the list.
>
> The correct changelog is
>
> gcc/
> 2017-11-15  Tamar Christina  <tamar.christina@arm.com>
>
> 	PR target/82641
> 	* config/arm/arm.c (arm_valid_target_attribute_rec):
> 	Parse "arch=" and "+<ext>".
> 	(arm_valid_target_attribute_tree): Re-init global options.
> 	(arm_option_override): Make non-static.
> 	(arm_options_perform_arch_sanity_checks): Make errors fatal.
> 	* config/arm/arm_acle.h (__ARM_FEATURE_CRC32): Replace with pragma.
> 	* doc/extend.texi (ARM Function Attributes): Add pragma and target.
>
> gcc/testsuite/
> 2017-11-15  Tamar Christina  <tamar.christina@arm.com>
>
> 	PR target/82641
> 	* gcc.target/arm/pragma_arch_attribute.c: New.
>
> Ok for trunk?

Thanks Tamar.
This is ok for trunk.
Kyrill

> Thanks,
> Tamar
>
>> Thanks,
>> Kyrill
>>
>>>>> Ok for trunk?
>>>>>
>>>>> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index
>>>>>
>> 8aa443f87fb700f7a723d736bdbd53b6c839656d..18d0ffa6820326ce7badf33001
>>>> b1
>>>>> c6a467c95883 100644
>>>>> --- a/gcc/doc/extend.texi
>>>>> +++ b/gcc/doc/extend.texi
>>>>> @@ -3858,6 +3858,42 @@ Specifies the fpu for which to tune the
>>>> performance of this function.
>>>>>   The behavior and permissible arguments are the same as for the
>>>>> @option{-mfpu=}  command-line option.
>>>>>
>>>>> +@item arch=
>>>>> +@cindex @code{arch=} function attribute, ARM Specifies the
>>>>> +architecture version and architectural extensions to use for this
>>>>> +function.  The behavior and permissible arguments are the same as
>>>>> +for the @option{-march=} command-line option.
>>>>> +
>>>>> +The above target attributes can be specified as follows:
>>>>> +
>>>>> +@smallexample
>>>>> +__attribute__((target("@var{attr-string}")))
>>>>> +int
>>>>> +f (int a)
>>>>> +@{
>>>>> +  return a + 5;
>>>>> +@}
>>>>> +@end smallexample
>>>>> +
>>>>> +where @code{@var{attr-string}} is one of the attribute strings.
>>>> This example doesn't illustrate anything useful, and in fact just
>>> confuses
>>>> things by introducing @var{attr-string}.  Please use an actual valid
>>> attribute
>>>> here, something like "arch=armv8-a" or whatever.
>>>>
>>>> Also, either kill the sentence fragment after the example, or be
>>> careful to
>>>> add @noindent before it to indicate it's a continuation of the
>>>> previous paragraph.
>>>>
>>>>> +
>>>>> +Additionally, the architectural extension string may be specified
>>>>> +on its own.  This can be used to turn on and off particular
>>>>> +architectural extensions without having to specify a particular
>>> architecture
>>>> version or core.  Example:
>>>>> +
>>>>> +@smallexample
>>>>> +__attribute__((target("+crc+nocrypto")))
>>>>> +int
>>>>> +foo (int a)
>>>>> +@{
>>>>> +  return a + 5;
>>>>> +@}
>>>>> +@end smallexample
>>>>> +
>>>>> +In this example @code{target("+crc+nocrypto")} enables the
>>>>> +@code{crc} extension and disables the @code{crypto} extension for
>>>>> +the function @code{foo} without modifying an existing
>>>>> +@option{-march=} or
>>>> @option{-mcpu} option.
>>>>> +
>>>>>   @end table
>>>>>
>>>>>   @end table
>>>> -Sandra