glsl: Support the 'invariant(all)' pragma

Previously the 'STDGL invariant(all)' pragma added in GLSL 1.20 was
simply ignored by the compiler.  This adds support for setting all
variable invariant.

In GLSL 1.10 and GLSL ES 1.00 the pragma is ignored, per the specs,
but a warning is generated.

Fixes piglit test glsl-invariant-pragma and bugzilla #31925.

NOTE: This is a candidate for the 7.9 and 7.10 branches.

1 files changed, 17 insertions, 0 deletions

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 80c4ef4314c..a8dcae6e810 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1852,6 +1852,23 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
    else if (qual->flags.q.uniform)
       var->mode = ir_var_uniform;
 
+   if (state->all_invariant && (state->current_function == NULL)) {
+      switch (state->target) {
+      case vertex_shader:
+	 if (var->mode == ir_var_out)
+	    var->invariant = true;
+	 break;
+      case geometry_shader:
+	 if ((var->mode == ir_var_in) || (var->mode == ir_var_out))
+	    var->invariant = true;
+	 break;
+      case fragment_shader:
+	 if (var->mode == ir_var_in)
+	    var->invariant = true;
+	 break;
+      }
+   }
+
    if (qual->flags.q.flat)
       var->interpolation = ir_var_flat;
    else if (qual->flags.q.noperspective)