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authorIan Romanick <ian.d.romanick@intel.com>2010-10-07 17:21:22 -0700
committerIan Romanick <ian.d.romanick@intel.com>2010-10-08 14:21:23 -0700
commit68a4fc9d5a9dd3b61472451d659275531253b67d (patch)
tree2458cf332f819c61cbdc589e637cc0f171328892 /src/glsl/ast_to_hir.cpp
parenteee68d3631813580a14fa51fda6f0c959279256c (diff)
glsl: Add linker support for explicit attribute locations
Diffstat (limited to 'src/glsl/ast_to_hir.cpp')
-rw-r--r--src/glsl/ast_to_hir.cpp18
1 files changed, 15 insertions, 3 deletions
diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 47fe7a32c3c..6e8a1fd1daa 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1668,9 +1668,21 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
string);
} else {
var->explicit_location = true;
- var->location = (state->target == vertex_shader)
- ? (qual->location + VERT_ATTRIB_GENERIC0)
- : (qual->location + FRAG_RESULT_DATA0);
+
+ /* This bit of silliness is needed because invalid explicit locations
+ * are supposed to be flagged during linking. Small negative values
+ * biased by VERT_ATTRIB_GENERIC0 or FRAG_RESULT_DATA0 could alias
+ * built-in values (e.g., -16+VERT_ATTRIB_GENERIC0 = VERT_ATTRIB_POS).
+ * The linker needs to be able to differentiate these cases. This
+ * ensures that negative values stay negative.
+ */
+ if (qual->location >= 0) {
+ var->location = (state->target == vertex_shader)
+ ? (qual->location + VERT_ATTRIB_GENERIC0)
+ : (qual->location + FRAG_RESULT_DATA0);
+ } else {
+ var->location = qual->location;
+ }
}
}