[Mesa-dev] [PATCH] utils/u_math: break dependency on gallium/utils

[Marek Olšák]

I think this will break non-GL gallium state trackers. src/mesa is
only for GL, which is why common gallium code and gallium drivers
can't use code from src/mesa.

Marek

On Sun, Sep 9, 2018 at 2:39 AM, Dylan Baker <dylan at pnwbakers.com> wrote:
> Currently u_math needs gallium utils for cpu detection.  Most of what
> u_math uses out of u_cpu_detection is duplicated in src/mesa/x86
> (surprise!), so I've just reworked it as much as possible to use the
> x86/common_x86_features macros instead of the gallium ones. There is
> one small function that was copied over, as promoting u_cpu_detection is
> itself a fairly hefty undertaking, as it depends on u_debug, and this
> fixes the bug for now.
>
> bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107870
> cc: vlee at freedesktop.org
> ---
>
> I have no idea if this fixes the build on mac, I had this in a branch where I
> started replacing more of imports.{h,c} with utils stuff, and this fixes some
> build problems on Linux. I don't have a mac to test on and I wont until Monday.
> If this works let me know.
>
>  src/util/u_math.c | 43 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 38 insertions(+), 5 deletions(-)
>
> diff --git a/src/util/u_math.c b/src/util/u_math.c
> index c58af911be7..bf0c398eeec 100644
> --- a/src/util/u_math.c
> +++ b/src/util/u_math.c
> @@ -29,7 +29,7 @@
>
>  #include "pipe/p_config.h"
>  #include "util/u_math.h"
> -#include "util/u_cpu_detect.h"
> +#include "x86/common_x86_features.h"
>
>  #if defined(PIPE_ARCH_SSE)
>  #include <xmmintrin.h>
> @@ -90,7 +90,7 @@ util_fpstate_get(void)
>     unsigned mxcsr = 0;
>
>  #if defined(PIPE_ARCH_SSE)
> -   if (util_cpu_caps.has_sse) {
> +   if (cpu_has_xmm) {
>        mxcsr = _mm_getcsr();
>     }
>  #endif
> @@ -98,6 +98,31 @@ util_fpstate_get(void)
>     return mxcsr;
>  }
>
> +/* TODO: this was copied from u_cpu_detection. It's another case of duplication
> + * between gallium and core mesa, and it would be nice to get rid of that
> + * duplication as well.
> + */
> +#if defined(PIPE_ARCH_X86)
> +PIPE_ALIGN_STACK static inline bool sse2_has_daz(void)
> +{
> +   struct {
> +      uint32_t pad1[7];
> +      uint32_t mxcsr_mask;
> +      uint32_t pad2[128-8];
> +   } PIPE_ALIGN_VAR(16) fxarea;
> +
> +   fxarea.mxcsr_mask = 0;
> +#if defined(PIPE_CC_GCC)
> +   __asm __volatile ("fxsave %0" : "+m" (fxarea));
> +#elif defined(PIPE_CC_MSVC) || defined(PIPE_CC_ICL)
> +   _fxsave(&fxarea);
> +#else
> +   fxarea.mxcsr_mask = 0;
> +#endif
> +   return !!(fxarea.mxcsr_mask & (1 << 6));
> +}
> +#endif
> +
>  /**
>   * Make sure that the fp treats the denormalized floating
>   * point numbers as zero.
> @@ -108,13 +133,21 @@ unsigned
>  util_fpstate_set_denorms_to_zero(unsigned current_mxcsr)
>  {
>  #if defined(PIPE_ARCH_SSE)
> -   if (util_cpu_caps.has_sse) {
> +   if (cpu_has_xmm) {
>        /* Enable flush to zero mode */
>        current_mxcsr |= _MM_FLUSH_ZERO_MASK;
> -      if (util_cpu_caps.has_daz) {
> +      /* x86_64 cpus always have daz, as do cpus with sse3 in fact, there's
> +       * basically only a handful of very early pentium 4's that have sse2 but
> +       * not daz.
> +       */
> +# if !defined(PIPE_ARCH_x86_64) && !defined(PIPE_ARCH_SSSE3)
> +      if (sse2_has_daz()) {
> +# endif
>           /* Enable denormals are zero mode */
>           current_mxcsr |= _MM_DENORMALS_ZERO_MASK;
> +# if !defined(PIPE_ARCH_x86_64) && !defined(PIPE_ARCH_SSSE3)
>        }
> +#endif
>        util_fpstate_set(current_mxcsr);
>     }
>  #endif
> @@ -130,7 +163,7 @@ void
>  util_fpstate_set(unsigned mxcsr)
>  {
>  #if defined(PIPE_ARCH_SSE)
> -   if (util_cpu_caps.has_sse) {
> +   if (cpu_has_xmm) {
>        _mm_setcsr(mxcsr);
>     }
>  #endif
> --
> 2.18.0
>
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