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spirv: Work around the Doom shader bug

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Doom shipped with a broken version of GLSLang which handles samplers as
function arguments in a way that isn't spec-compliant.  In particular,
it creates a temporary local sampler variable and copies the sampler
into it.  While Dave has had a hack patch out for a while that gets it
working, we've never landed it because we've been hoping that a game
update would come out with fixed shaders.  Unfortunately, no game update
appears on to be on the horizon and I've found this issue in yet another
application so I think we're stuck working around it.  Hopefully, we can
delete this code one day.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99467
Cc: "17.1" <mesa-stable@lists.freedesktop.org>
Tested-by: Grazvydas Ignotas <notasas@gmail.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Jason Ekstrand 2017-06-20 09:06:44 -07:00
parent 93055576ae
commit 1bd0acab21
2 changed files with 28 additions and 0 deletions
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14
src/compiler/spirv/vtn_private.h
View file

@ -288,6 +288,20 @@ struct vtn_variable {
nir_variable *var;
nir_variable **members;
/**
* In some early released versions of GLSLang, it implemented all function
* calls by making copies of all parameters into temporary variables and
* passing those variables into the function. It even did so for samplers
* and images which violates the SPIR-V spec. Unfortunately, two games
* (Talos Principle and Doom) shipped with this old version of GLSLang and
* also happen to pass samplers into functions. Talos Principle received
* an update fairly shortly after release with an updated GLSLang. Doom,
* on the other hand, has never received an update so we need to work
* around this GLSLang issue in SPIR-V -> NIR. Hopefully, we can drop this
* hack at some point in the future.
*/
struct vtn_access_chain *copy_prop_sampler;
struct vtn_access_chain chain;
};

14
src/compiler/spirv/vtn_variables.c
View file

@ -96,6 +96,10 @@ rewrite_deref_types(nir_deref *deref, const struct glsl_type *type)
nir_deref_var *
vtn_access_chain_to_deref(struct vtn_builder *b, struct vtn_access_chain *chain)
{
/* Do on-the-fly copy propagation for samplers. */
if (chain->var->copy_prop_sampler)
return vtn_access_chain_to_deref(b, chain->var->copy_prop_sampler);
nir_deref_var *deref_var;
if (chain->var->var) {
deref_var = nir_deref_var_create(b, chain->var->var);
@ -1613,6 +1617,16 @@ vtn_handle_variables(struct vtn_builder *b, SpvOp opcode,
case SpvOpStore: {
struct vtn_access_chain *dest =
vtn_value(b, w[1], vtn_value_type_access_chain)->access_chain;
if (glsl_type_is_sampler(dest->var->type->type)) {
vtn_warn("OpStore of a sampler detected. Doing on-the-fly copy "
"propagation to workaround the problem.");
assert(dest->var->copy_prop_sampler == NULL);
dest->var->copy_prop_sampler =
vtn_value(b, w[2], vtn_value_type_access_chain)->access_chain;
break;
}
struct vtn_ssa_value *src = vtn_ssa_value(b, w[2]);
vtn_variable_store(b, src, dest);
break;