On 17/03/15 23:44, Emil Velikov wrote:
> On 17/03/15 01:25, Jonathan Gray wrote:
>> On Mon, Mar 16, 2015 at 08:37:28PM +0000, Emil Velikov wrote:
>>> On 26/02/15 13:49, Jose Fonseca wrote:
>>>> On 26/02/15 13:42, Jose Fonseca wrote:
>>>>> On 26/02/15 03:55, Jonathan Gray wrote:
>>>>>> On Wed, Feb 25, 2015 at 07:09:26PM -0800, Matt Turner wrote:
>>>>>>> On Wed, Feb 25, 2015 at 7:03 PM, Jonathan Gray <j...@jsg.id.au> wrote:
>>>>>>>> On Wed, Feb 25, 2015 at 06:53:14PM -0800, Matt Turner wrote:
>>>>>>>>> On Wed, Feb 25, 2015 at 5:37 PM, Jonathan Gray <j...@jsg.id.au> wrote:
>>>>>>>>>> If it isn't going to be configure checks could someone merge the
>>>>>>>>>> original patch in this thread?
>>>>>>>>>
>>>>>>>>> I committed
>>>>>>>>>
>>>>>>>>> commit 3492e88090d2d0c0bfbc934963b8772b45fc8880
>>>>>>>>> Author: Matt Turner <matts...@gmail.com>
>>>>>>>>> Date: Fri Feb 20 18:46:43 2015 -0800
>>>>>>>>>
>>>>>>>>> gallium/util: Use HAVE___BUILTIN_* macros.
>>>>>>>>>
>>>>>>>>> Reviewed-by: Eric Anholt <e...@anholt.net>
>>>>>>>>> Reviewed-by: Jose Fonseca <jfons...@vmware.com>
>>>>>>>>>
>>>>>>>>> which switched over a bunch of preprocessor checks around __builtin*
>>>>>>>>> calls to use the macros defined by autotools.
>>>>>>>>>
>>>>>>>>> So I think cleaning it up to use __builtin_ffs* first #ifdef
>>>>>>>>> HAVE___BUILTIN_* can go forward now.
>>>>>>>>
>>>>>>>> Yes but there is no HAVE_FFSLL for constructs like
>>>>>>>>
>>>>>>>> #if !defined(HAVE_FFSLL) && defined(HAVE___BUILTIN_FFSLL)
>>>>>>>>
>>>>>>>> or is it ok to always use the builtin?
>>>>>>>
>>>>>>> I think the question is whether it's okay to always use the builtin if
>>>>>>> it's available (as opposed to libc functions). I think the answer to
>>>>>>> that is yes.
>>>>>>
>>>>>> So in that case how about the following? Or is it going to break
>>>>>> the android scons build?
>>>>>>
>>>>>> From cba39ba72115e57d262cb4b099c4e72106f01812 Mon Sep 17 00:00:00 2001
>>>>>> From: Jonathan Gray <j...@jsg.id.au>
>>>>>> Date: Thu, 26 Feb 2015 14:46:45 +1100
>>>>>> Subject: [PATCH] gallium/util: use ffs* builtins if available
>>>>>>
>>>>>> Required to build on OpenBSD which doesn't have ffsll in libc.
>>>>>>
>>>>>> Signed-off-by: Jonathan Gray <j...@jsg.id.au>
>>>>>> ---
>>>>>> src/gallium/auxiliary/util/u_math.h | 11 ++++++++---
>>>>>> 1 file changed, 8 insertions(+), 3 deletions(-)
>>>>>>
>>>>>> diff --git a/src/gallium/auxiliary/util/u_math.h
>>>>>> b/src/gallium/auxiliary/util/u_math.h
>>>>>> index b4a65e4..5bc9b97 100644
>>>>>> --- a/src/gallium/auxiliary/util/u_math.h
>>>>>> +++ b/src/gallium/auxiliary/util/u_math.h
>>>>>> @@ -384,9 +384,6 @@ unsigned ffs( unsigned u )
>>>>>>
>>>>>> return i;
>>>>>> }
>>>>>> -#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID)
>>>>>> -#define ffs __builtin_ffs
>>>>>> -#define ffsll __builtin_ffsll
>>>>>
>>>>> Scons does define HAVE___BUILTIN_FFS for mingw.
>>>>>
>>>>> However `git grep '\<ffs\>` shows ffs is used directly in many other
>>>>> places. So I suspect this change will break them.
>>>>>
>>>>>> #endif
>>>>>>
>>>>>> #endif /* FFS_DEFINED */
>>>>>> @@ -435,7 +432,11 @@ util_last_bit_signed(int i)
>>>>>> static INLINE int
>>>>>> u_bit_scan(unsigned *mask)
>>>>>> {
>>>>>> +#if defined(HAVE___BUILTIN_FFS)
>>>>>> + int i = __builtin_ffs(*mask) - 1;
>>>>>> +#else
>>>>>> int i = ffs(*mask) - 1;
>>>>>> +#endif
>>>>>> *mask &= ~(1 << i);
>>>>>> return i;
>>>>>> }
>>>>>> @@ -444,7 +445,11 @@ u_bit_scan(unsigned *mask)
>>>>>> static INLINE int
>>>>>> u_bit_scan64(uint64_t *mask)
>>>>>> {
>>>>>> +#if defined(HAVE___BUILTIN_FFSLL)
>>>>>> + int i = __builtin_ffsll(*mask) - 1;
>>>>>> +#else
>>>>>> int i = ffsll(*mask) - 1;
>>>>>> +#endif
>>>>>> *mask &= ~(1llu << i);
>>>>>> return i;
>>>>>> }
>>>>>>
>>>>>
>>>>>
>>>>> I think the right thing long term is to provide ffs and ffsll in
>>>>> c99_compat.h or c99_math.h for all platforms. And let the rest of the
>>>>> code just always assume it's available somehow.
>>>>>
>>>>>
>>>>> Otherwise, let's just '#define ffs __builtin_ffs' on OpenBSD too.
>>>>
>>>> In other words, the original patch on this thread
>>>>
>>>> http://lists.freedesktop.org/archives/mesa-dev/2015-February/076071.html
>>>>
>>>> is the only patch I've seen so far that doesn't break Mingw.
>>>>
>>>> If you rather use HAVE___BUILTIN_FFSLL, then just do
>>>>
>>>> diff --git a/src/gallium/auxiliary/util/u_math.h
>>>> b/src/gallium/auxiliary/util/u_math.h
>>>> index 959f76e..d372cfd 100644
>>>> --- a/src/gallium/auxiliary/util/u_math.h
>>>> +++ b/src/gallium/auxiliary/util/u_math.h
>>>> @@ -384,7 +384,7 @@ unsigned ffs( unsigned u )
>>>>
>>>> return i;
>>>> }
>>>> -#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID)
>>>> +#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID) ||
>>>> defined(HAVE___BUILTIN_FFSLL)
>>>> #define ffs __builtin_ffs
>>>> #define ffsll __builtin_ffsll
>>>> #endif
>>>>
>>> Jonathan
>>>
>>> Seems like this has ended up a longer discussion that anticipated :\
>>> Can you please confirm if the above works for you ?
>>>
>>> Thanks
>>> Emil
>>
>> It looks like that diff was mangled by the mail client and doesn't have
>> the newline escaped. It also assumes a ffsll builtin implies a ffs
>> builtin is present. So how about the following instead:
>>
>> diff --git a/src/gallium/auxiliary/util/u_math.h
>> b/src/gallium/auxiliary/util/u_math.h
>> index 8f62cac..89c63d7 100644
>> --- a/src/gallium/auxiliary/util/u_math.h
>> +++ b/src/gallium/auxiliary/util/u_math.h
>> @@ -383,14 +383,28 @@ unsigned ffs( unsigned u )
>>
>> return i;
>> }
>> -#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID)
>> +#elif defined(__MINGW32__) || defined(PIPE_OS_ANDROID) || \
>> + defined(HAVE___BUILTIN_FFS)
>> #define ffs __builtin_ffs
>> -#define ffsll __builtin_ffsll
>> #endif
>>
>> #endif /* FFS_DEFINED */
>>
>> /**
>> + * Find first bit set in long long. Least significant bit is 1.
>> + * Return 0 if no bits set.
>> + */
>> +#ifndef FFSLL_DEFINED
>> +#define FFSLL_DEFINED 1
>> +
>> +#if defined(__MINGW32__) || defined(PIPE_OS_ANDROID) || \
>> + defined(HAVE___BUILTIN_FFSLL)
>> +#define ffsll __builtin_ffsll
>> +#endif
>> +
>> +#endif /* FFSLL_DEFINED */
>> +
>> +/**
>> * Find last bit set in a word. The least significant bit is 1.
>> * Return 0 if no bits are set.
>> */
>>
> Looks ok to me. Afaict splitting out __builtin_ffs and __builtin_ffsll
> is a nice idea, as one does have to imply the other. Haven't seen any
> references behind the FFS_DEFINED guards, although I'd assume that is to
> prevent clashing with the one in classic mesa.
>
> Reviewed-by: Emil Velikov <emil.l.veli...@gmail.com>
>
Fwiw, I will be commiting this in the next few days unless there are any
objections.
-Emil
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