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Commit 3fe9fe9c authored by Tapani Pälli's avatar Tapani Pälli Committed by Emil Velikov
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glsl: validate sampler array indexing for 'constant-index-expression'


Desktop GLSL < 130 and GLSL ES < 300 allow sampler array indexing where
index can contain a loop induction variable. This extra check will warn
during linking if some of the indexes could not be turned in to constant
expressions.

v2: warning instead of error for backends that did not enable
    EmitNoIndirectSampler option (have dynamic indexing)

Signed-off-by: default avatarTapani Pälli <tapani.palli@intel.com>
Reviewed-by: default avatarFrancisco Jerez <currojerez@riseup.net>
Cc: "10.5" and "10.6" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit 9350ea69)
parent 1beb6738
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......@@ -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
......@@ -2738,6 +2771,40 @@ 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).
*/
static bool
validate_sampler_array_indexing(struct gl_context *ctx,
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;
bool no_dynamic_indexing =
ctx->Const.ShaderCompilerOptions[i].EmitNoIndirectSampler;
/* Search for array derefs in shader. */
v.run(prog->_LinkedShaders[i]->ir);
if (v.uses_dynamic_sampler_array_indexing()) {
const char *msg = "sampler arrays indexed with non-constant "
"expressions is forbidden in GLSL %s %u";
/* Backend has indicated that it has no dynamic indexing support. */
if (no_dynamic_indexing) {
linker_error(prog, msg, prog->IsES ? "ES" : "", prog->Version);
return false;
} else {
linker_warning(prog, msg, prog->IsES ? "ES" : "", prog->Version);
}
}
}
return true;
}
void
link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
......@@ -2956,6 +3023,16 @@ 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 check emits a warning or error
* depending if backend can handle dynamic indexing.
*/
if ((!prog->IsES && prog->Version < 130) ||
(prog->IsES && prog->Version < 300)) {
if (!validate_sampler_array_indexing(ctx, prog))
goto done;
}
/* Check and validate stream emissions in geometry shaders */
validate_geometry_shader_emissions(ctx, prog);
......
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