glsl: permit explicit locations on fragment shader outputs, not inputs

From the OpenGL docs for GL_ARB_explicit_attrib_location:

    This extension provides a method to pre-assign attribute locations to
    named vertex shader inputs and color numbers to named fragment shader
    outputs.

This was accidentally implemented for fragment shader inputs.  This
patch fixes it to apply to fragment shader outputs.

Fixes piglit tests
spec/ARB_explicit_attrib_location/1.{10,20}/compiler/layout-{01,03,06,07,08,09,10}.frag

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
NOTE: This is a candidate for the 7.10 and 7.11 branches.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38624

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index 3b87f0d56de8543fd2099e1bba5b0760ce37f0b0..35cb20670604d1b235ce891be7c79eb7ed06cbe9 100644 (file)
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -1940,7 +1940,7 @@ apply_type_qualifier_to_variable(const struct ast_type_qualifier *qual,
         break;
 
       case fragment_shader:
-        if (!global_scope || (var->mode != ir_var_in)) {
+        if (!global_scope || (var->mode != ir_var_out)) {
            fail = true;
            string = "output";
         }