[Mesa-dev] [PATCH] gallium/util: Define ffsll on OpenBSD.

[Jonathan Gray]

On Wed, Feb 25, 2015 at 07:09:26PM -0800, Matt Turner wrote:
> On Wed, Feb 25, 2015 at 7:03 PM, Jonathan Gray <jsg at 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 <jsg at 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 <mattst88 at gmail.com>
> >> Date:   Fri Feb 20 18:46:43 2015 -0800
> >>
> >>     gallium/util: Use HAVE___BUILTIN_* macros.
> >>
> >>     Reviewed-by: Eric Anholt <eric at anholt.net>
> >>     Reviewed-by: Jose Fonseca <jfonseca at 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 <jsg at 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 <jsg at 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
 #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;
 }
-- 
2.3.0