spirv: Work around the Doom shader bug

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" <[email protected]>
Tested-by: Grazvydas Ignotas <[email protected]>
Reviewed-by: Dave Airlie <[email protected]>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/compiler/spirv/vtn_private.h b/src/compiler/spirv/vtn_private.h
index 59fcc94fcda..a377c901446 100644
--- a/src/compiler/spirv/vtn_private.h
+++ b/src/compiler/spirv/vtn_private.h
@@ -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;
 };