From cc744a0947e619a4350551f5e9d5e380ac8d9e23 Mon Sep 17 00:00:00 2001
From: Francisco Jerez <currojerez@riseup.net>
Date: Fri, 20 Sep 2013 14:58:03 -0700
Subject: [PATCH] glsl: Add type predicate to check whether a type contains any
 opaque types.

And use it to forbid comparisons of opaque operands.  According to the
GL 4.2 specification:

> Except for array indexing, structure member selection, and
> parentheses, opaque variables are not allowed to be operands in
> expressions.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
---
 src/glsl/ast_to_hir.cpp |  4 ++++
 src/glsl/glsl_types.cpp | 18 ++++++++++++++++++
 src/glsl/glsl_types.h   |  5 +++++
 3 files changed, 27 insertions(+)

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index fa0d8c9..71e57ec 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1238,6 +1238,10 @@ ast_expression::hir(exec_list *instructions,
                  !state->check_version(120, 300, &loc,
                                        "array comparisons forbidden")) {
 	 error_emitted = true;
+      } else if ((op[0]->type->contains_opaque() ||
+                  op[1]->type->contains_opaque())) {
+         _mesa_glsl_error(&loc, state, "opaque type comparisons forbidden");
+         error_emitted = true;
       }
 
       if (error_emitted) {
diff --git a/src/glsl/glsl_types.cpp b/src/glsl/glsl_types.cpp
index 281e690..f740130 100644
--- a/src/glsl/glsl_types.cpp
+++ b/src/glsl/glsl_types.cpp
@@ -168,6 +168,24 @@ glsl_type::contains_integer() const
    }
 }
 
+bool
+glsl_type::contains_opaque() const {
+   switch (base_type) {
+   case GLSL_TYPE_SAMPLER:
+   case GLSL_TYPE_ATOMIC_UINT:
+      return true;
+   case GLSL_TYPE_ARRAY:
+      return element_type()->contains_opaque();
+   case GLSL_TYPE_STRUCT:
+      for (unsigned int i = 0; i < length; i++) {
+         if (fields.structure[i].type->contains_opaque())
+            return true;
+      }
+      return false;
+   default:
+      return false;
+   }
+}
 
 gl_texture_index
 glsl_type::sampler_index() const
diff --git a/src/glsl/glsl_types.h b/src/glsl/glsl_types.h
index 69ad4b8..fdb1f3a 100644
--- a/src/glsl/glsl_types.h
+++ b/src/glsl/glsl_types.h
@@ -463,6 +463,11 @@ struct glsl_type {
    }
 
    /**
+    * Return whether a type contains any opaque types.
+    */
+   bool contains_opaque() const;
+
+   /**
     * Query the full type of a matrix row
     *
     * \return
-- 
2.7.4