[Mesa-dev] Mesa (master): st/mesa: fix incorrect size of UBO declarations

[Michel Dänzer]

On 02.07.2014 00:43, Brian Paul wrote:
> Module: Mesa
> Branch: master
> Commit: f4b0ab7afd83c811329211eae8167c9bf238870c
> URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f4b0ab7afd83c811329211eae8167c9bf238870c
> 
> Author: Brian Paul <brianp at vmware.com>
> Date:   Tue Jul  1 08:17:09 2014 -0600
> 
> st/mesa: fix incorrect size of UBO declarations
> 
> UniformBufferSize is in bytes so we need to divide by 16 to get the
> number of constant buffer slots.  Also, the ureg_DECL_constant2D()
> function takes first..last parameters so we need to subtract one
> for the last value.

This change broke the GLSL uniform_buffer fs/vs/gs-struct-pad piglit
tests with radeonsi:

../../../../src/gallium/auxiliary/gallivm/lp_bld_tgsi.c:306:lp_build_emit_fetch: Assertion `reg->Register.Index <= bld_base->info->file_max[reg->Register.File]' failed.

AFAICT reg->Register.Index is 2, and the new code calls
ureg_DECL_constant2D() with last=1. This is the TGSI code:

FRAG
PROPERTY FS_COLOR0_WRITES_ALL_CBUFS 1
DCL OUT[0], COLOR
DCL CONST[1][0..1]
DCL TEMP[0], LOCAL
IMM[0] UINT32 {0, 16, 32, 0}
  0: MOV TEMP[0].x, CONST[1][0].xxxx
  1: MOV TEMP[0].y, CONST[1][1].xxxx
  2: MOV TEMP[0].z, CONST[1][2].xxxx
  3: MOV TEMP[0].w, CONST[1][2].xxxx
  4: MOV OUT[0], TEMP[0]
  5: END

which results from this GLSL code:

#version 140

struct S1 {
        float r;
};

struct S2 {
        float g;
        float b;
        float a;
};

struct S {
       S1 s1;
       S2 s2;
};

uniform ubo1 {
        S s;
};

void main()
{
        gl_FragColor = vec4(s.s1.r, s.s2.g, s.s2.b, s.s2.a);
}


Something doesn't seem to add up, but I'm not sure where exactly the
problem is or how to fix it.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer