From b57c1ec4219f01bfdb98bcab8fca4c44e87bd1a4 Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Fri, 11 Jan 2019 14:17:24 -0600 Subject: spirv: Whack sampler/image pointers to uniform A long time in a galaxy far far away, there was a GLSLang bug with how it handled samplers passed in as function parameters. (The bug can be found here: https://github.com/KhronosGroup/glslang/issues/179.) Unfortunately, that version was shipped in several apps and has been causing heartburn for our SPIR-V parser ever since. Recent changes to NIR uncovered a moderately old bug in how we work around this issue. In particular, we ended up with a deref_cast from uniform to local which is not a no-op cast so nir_opt_deref wasn't getting rid of the cast. The only reason why it worked before was because someone just happened to call nir_fixup_deref_modes which "fixed" the cast (that shouldn't be happening) and then a later round of copy-prop would get rid of it. The fact that the deref_cast survived that long without causing trouble for other parts of NIR is a bit surprising. Just whacking the mode of the pointer seems to fix it fairly unobtrusively. Currently, only apps with this bug will have a local variable containing an image or sampler. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109304 Reviewed-by: Lionel Landwerlin --- src/compiler/spirv/vtn_variables.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'src/compiler') diff --git a/src/compiler/spirv/vtn_variables.c b/src/compiler/spirv/vtn_variables.c index 50cd1b42c69..6036295e61c 100644 --- a/src/compiler/spirv/vtn_variables.c +++ b/src/compiler/spirv/vtn_variables.c @@ -1800,6 +1800,18 @@ vtn_pointer_from_ssa(struct vtn_builder *b, nir_ssa_def *ssa, ptr->type = ptr_type->deref; ptr->ptr_type = ptr_type; + /* To work around https://github.com/KhronosGroup/glslang/issues/179 we + * need to whack the mode because it creates a function parameter with the + * Function storage class even though it's a pointer to a sampler. If we + * don't do this, then NIR won't get rid of the deref_cast for us. + */ + if (ptr->mode == vtn_variable_mode_function && + (ptr->type->base_type == vtn_base_type_sampler || + ptr->type->base_type == vtn_base_type_sampled_image)) { + ptr->mode = vtn_variable_mode_uniform; + nir_mode = nir_var_uniform; + } + if (vtn_pointer_uses_ssa_offset(b, ptr)) { /* This pointer type needs to have actual storage */ vtn_assert(ptr_type->type); -- cgit v1.2.3