From: Brendan Tildesley <mail@brendan.scot>
To: 35575@debbugs.gnu.org
Subject: bug#35575: logo,Some graphical programs borked with Guix on Arch
Date: Sun, 29 Mar 2020 15:00:57 +1100 [thread overview]
Message-ID: <adaf110a-cf9a-4df5-b27a-f119a73f9b95@brendan.scot> (raw)
In-Reply-To: <c276ed96-e5a0-975d-7954-77b8831487c0@brendan.scot>
To follow up on this old bug, I believe the issue may come from here:
https://gitlab.freedesktop.org/mesa/mesa/-/blob/master/src/compiler/glsl/shader_cache.cpp#L144
Mesa calculates a sha1 based on some things they reason affect the
output, but likely it is not truely a function of every parameter than
can make a difference to the shader output. When we updated from llvm6
to lvm7 I'm guessing it changed the shaders somehow, and the llvm
version is not included in the hash. Since I have zero understanding
mesa, I'm not capable of determining the best solution. One thought is
that if we included the mesa /gnu/store path in the calculation, this
would make the hash's truely unique for a given mesa version, but also
cached shaders that /would/ work would be routinely discarded after an
update (i assume?). Would this be sensible or completely break something
else? Should we just add the llvm version, or just start a mesa bug
report asking for input?
The code:
ralloc_asprintf_append(&buf, "tf: %d ", prog->TransformFeedback.BufferMode);
for (unsigned int i = 0; i < prog->TransformFeedback.NumVarying; i++) {
ralloc_asprintf_append(&buf, "%s ",
prog->TransformFeedback.VaryingNames[i]);
}
/* SSO has an effect on the linked program so include this when
generating
* the sha also.
*/
ralloc_asprintf_append(&buf, "sso: %s\n",
prog->SeparateShader ? "T" : "F");
/* A shader might end up producing different output depending on the
glsl
* version supported by the compiler. For example a different path
might be
* taken by the preprocessor, so add the version to the hash input.
*/
ralloc_asprintf_append(&buf, "api: %d glsl: %d fglsl: %d\n",
ctx->API, ctx->Const.GLSLVersion,
ctx->Const.ForceGLSLVersion);
/* We run the preprocessor on shaders after hashing them, so we need to
* add any extension override vars to the hash. If we don't do this the
* preprocessor could result in different output and we could load the
* wrong shader.
*/
char *ext_override = getenv("MESA_EXTENSION_OVERRIDE");
if (ext_override) {
ralloc_asprintf_append(&buf, "ext:%s", ext_override);
}
/* DRI config options may also change the output from the compiler so
* include them as an input to sha1 creation.
*/
char sha1buf[41];
_mesa_sha1_format(sha1buf, ctx->Const.dri_config_options_sha1);
ralloc_strcat(&buf, sha1buf);
for (unsigned i = 0; i < prog->NumShaders; i++) {
struct gl_shader *sh = prog->Shaders[i];
_mesa_sha1_format(sha1buf, sh->sha1);
ralloc_asprintf_append(&buf, "%s: %s\n",
_mesa_shader_stage_to_abbrev(sh->Stage), sha1buf);
next prev parent reply other threads:[~2020-03-30 2:36 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-05 7:58 bug#35575: Some graphical programs borked with Guix on Arch Brendan Tildesley
2019-05-05 10:33 ` Boris A. Dekshteyn
2019-05-07 11:09 ` Brendan Tildesley
2019-05-08 9:42 ` Boris A. Dekshteyn
2020-03-29 4:00 ` Brendan Tildesley [this message]
2020-03-31 14:53 ` bug#35575: logo,Some " Marius Bakke
2021-02-22 8:31 ` bug#35575: closing. bug has not reoccurred since Brendan Tildesley
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