Desktop GLSL < 130 and GLSL ES < 300 allow sampler array indexing where
index can contain a loop induction variable. This extra check makes sure
that all these indexes turn in to constant expressions during
compilation/linking.
Signed-off-by: Tapani Pälli <tapani.pa...@intel.com>
Cc: "10.5" and "10.6" <mesa-sta...@lists.freedesktop.org>
---
src/glsl/linker.cpp | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 71 insertions(+)
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index ecdc025..729b27f 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -346,6 +346,39 @@ private:
bool uses_non_zero_stream;
};
+/* Class that finds array derefs and check if indexes are dynamic. */
+class dynamic_sampler_array_indexing_visitor : public ir_hierarchical_visitor
+{
+public:
+ dynamic_sampler_array_indexing_visitor() :
+ dynamic_sampler_array_indexing(false)
+ {
+ }
+
+ ir_visitor_status visit_enter(ir_dereference_array *ir)
+ {
+ if (!ir->variable_referenced())
+ return visit_continue;
+
+ if (!ir->variable_referenced()->type->contains_sampler())
+ return visit_continue;
+
+ if (!ir->array_index->constant_expression_value()) {
+ dynamic_sampler_array_indexing = true;
+ return visit_stop;
+ }
+ return visit_continue;
+ }
+
+ bool uses_dynamic_sampler_array_indexing()
+ {
+ return dynamic_sampler_array_indexing;
+ }
+
+private:
+ bool dynamic_sampler_array_indexing;
+};
+
} /* anonymous namespace */
void
@@ -2736,6 +2769,34 @@ build_program_resource_list(struct gl_context *ctx,
*/
}
+/**
+ * This check is done to make sure we allow only constant expression
+ * indexing and "constant-index-expression" (indexing with an expression
+ * that includes loop induction variable).
+ */
+bool
+validate_sampler_array_indexing(struct gl_shader_program *prog)
+{
+ dynamic_sampler_array_indexing_visitor v;
+ for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+ if (prog->_LinkedShaders[i] == NULL)
+ continue;
+
+ /* Search for array derefs in shader. */
+ v.run(prog->_LinkedShaders[i]->ir);
+
+ if (v.uses_dynamic_sampler_array_indexing()) {
+ linker_error(prog,
+ "sampler arrays indexed with non-constant "
+ "expressions is forbidden in GLSL %s %u",
+ prog->IsES ? "ES" : "", prog->Version);
+ return false;
+ }
+ }
+
+ return true;
+}
+
void
link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
@@ -2948,6 +3009,16 @@ link_shaders(struct gl_context *ctx, struct
gl_shader_program *prog)
lower_const_arrays_to_uniforms(prog->_LinkedShaders[i]->ir);
}
+ /* Validation for special cases where we allow sampler array indexing
+ * with loop induction variable. This makes sure that all such cases
+ * have been turned in to constant expressions.
+ */
+ if ((!prog->IsES && prog->Version < 130) ||
+ (prog->IsES && prog->Version < 300)) {
+ if (!validate_sampler_array_indexing(prog))
+ goto done;
+ }
+
/* Check and validate stream emissions in geometry shaders */
validate_geometry_shader_emissions(ctx, prog);
--
2.1.0
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