On 07/01/2014 08:43 PM, Michel Dänzer wrote:
On 02.07.2014 00:43, Brian Paul wrote:
Module: Mesa
Branch: master
Commit: f4b0ab7afd83c811329211eae8167c9bf238870c
URL:
https://urldefense.proofpoint.com/v1/url?u=http://cgit.freedesktop.org/mesa/mesa/commit/?id%3Df4b0ab7afd83c811329211eae8167c9bf238870c&k=oIvRg1%2BdGAgOoM1BIlLLqw%3D%3D%0A&r=lGQMzzTgII0I7jefp2FHq7WtZ%2BTLs8wadB%2BiIj9xpBY%3D%0A&m=X5dPXUSLXb%2B60RW5%2FHCgcIkPXz083MgfZAbiRJFVOxc%3D%0A&s=c9766b9e3797ccad30888c534fae5891f9a7313418a228c81c0528230412cf1c
Author: Brian Paul <bri...@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.
I think there's at least a one GLSL compiler bug exposed here.
From the code fragments above, the z and w components of TEMP[0] are
getting the same value when they should not.
I reverted Mesa to before my changes and modified the piglit test to use
different values for the blue/alpha channels and it fails (nvidia
passes). We were just getting lucky before my changes.
I suspect the code which is laying out the floats in the UBO is doing
something wrong, and the size of the UBO is miscalculated as a result.
I'll dig a bit more but I think someone more familiar with the compiler
will need to help.
-Brian
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