[Mesa-dev] [PATCH] glsl: Document and enforce restriction on type values

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Cc: Dave Airlie <airlied at redhat.com>
---
 src/compiler/glsl_types.cpp | 7 +++++++
 src/compiler/glsl_types.h   | 3 +++
 2 files changed, 10 insertions(+)

diff --git a/src/compiler/glsl_types.cpp b/src/compiler/glsl_types.cpp
index 6e107a7..1539f5a 100644
--- a/src/compiler/glsl_types.cpp
+++ b/src/compiler/glsl_types.cpp
@@ -55,6 +55,13 @@ glsl_type::glsl_type(GLenum gl_type,
    vector_elements(vector_elements), matrix_columns(matrix_columns),
    length(0)
 {
+   /* Values of these types must fit in the two bits of
+    * glsl_type::sampled_type.
+    */
+   STATIC_ASSERT((unsigned(GLSL_TYPE_UINT)  & 3) == unsigned(GLSL_TYPE_UINT));
+   STATIC_ASSERT((unsigned(GLSL_TYPE_INT)   & 3) == unsigned(GLSL_TYPE_INT));
+   STATIC_ASSERT((unsigned(GLSL_TYPE_FLOAT) & 3) == unsigned(GLSL_TYPE_FLOAT));
+
    mtx_lock(&glsl_type::mutex);
 
    init_ralloc_type_ctx();
diff --git a/src/compiler/glsl_types.h b/src/compiler/glsl_types.h
index c3a0185..7c4827d 100644
--- a/src/compiler/glsl_types.h
+++ b/src/compiler/glsl_types.h
@@ -47,6 +47,9 @@ _mesa_glsl_release_types(void);
 #endif
 
 enum glsl_base_type {
+   /* Note: GLSL_TYPE_UINT, GLSL_TYPE_INT, and GLSL_TYPE_FLOAT must be 0, 1,
+    * and 2 so that they will fit in the 2 bits of glsl_type::sampled_type.
+    */
    GLSL_TYPE_UINT = 0,
    GLSL_TYPE_INT,
    GLSL_TYPE_FLOAT,
-- 
2.5.5