+
+static glsl_interp_qualifier
+interpret_interpolation_qualifier(const struct ast_type_qualifier *qual,
+ ir_variable_mode mode,
+ struct _mesa_glsl_parse_state *state,
+ YYLTYPE *loc)
+{
+ glsl_interp_qualifier interpolation;
+ if (qual->flags.q.flat)
+ interpolation = INTERP_QUALIFIER_FLAT;
+ else if (qual->flags.q.noperspective)
+ interpolation = INTERP_QUALIFIER_NOPERSPECTIVE;
+ else if (qual->flags.q.smooth)
+ interpolation = INTERP_QUALIFIER_SMOOTH;
+ else
+ interpolation = INTERP_QUALIFIER_NONE;
+
+ if (interpolation != INTERP_QUALIFIER_NONE) {
+ if (mode != ir_var_shader_in && mode != ir_var_shader_out) {
+ _mesa_glsl_error(loc, state,
+ "interpolation qualifier `%s' can only be applied to "
+ "shader inputs or outputs.",
+ interpolation_string(interpolation));
+
+ }
+
+ if ((state->stage == MESA_SHADER_VERTEX && mode == ir_var_shader_in) ||
+ (state->stage == MESA_SHADER_FRAGMENT && mode == ir_var_shader_out)) {
+ _mesa_glsl_error(loc, state,
+ "interpolation qualifier `%s' cannot be applied to "
+ "vertex shader inputs or fragment shader outputs",
+ interpolation_string(interpolation));
+ }
+ }
+
+ return interpolation;
+}
+
+
+static void
+validate_explicit_location(const struct ast_type_qualifier *qual,
+ ir_variable *var,
+ struct _mesa_glsl_parse_state *state,
+ YYLTYPE *loc)
+{
+ bool fail = false;
+
+ /* In the vertex shader only shader inputs can be given explicit
+ * locations.
+ *
+ * In the fragment shader only shader outputs can be given explicit
+ * locations.
+ */
+ switch (state->stage) {
+ case MESA_SHADER_VERTEX:
+ if (var->data.mode == ir_var_shader_in) {
+ if (!state->check_explicit_attrib_location_allowed(loc, var))
+ return;
+
+ break;
+ }
+
+ fail = true;
+ break;
+
+ case MESA_SHADER_GEOMETRY:
+ _mesa_glsl_error(loc, state,
+ "geometry shader variables cannot be given "
+ "explicit locations");
+ return;
+
+ case MESA_SHADER_FRAGMENT:
+ if (var->data.mode == ir_var_shader_out) {
+ if (!state->check_explicit_attrib_location_allowed(loc, var))
+ return;
+
+ break;
+ }
+
+ fail = true;
+ break;
+
+ case MESA_SHADER_COMPUTE:
+ _mesa_glsl_error(loc, state,
+ "compute shader variables cannot be given "
+ "explicit locations");
+ return;
+ };
+
+ if (fail) {
+ _mesa_glsl_error(loc, state,
+ "%s cannot be given an explicit location in %s shader",
+ mode_string(var),
+ _mesa_shader_stage_to_string(state->stage));
+ } else {
+ var->data.explicit_location = true;
+
+ /* 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->data.location = (state->stage == MESA_SHADER_VERTEX)
+ ? (qual->location + VERT_ATTRIB_GENERIC0)
+ : (qual->location + FRAG_RESULT_DATA0);
+ } else {
+ var->data.location = qual->location;
+ }
+
+ if (qual->flags.q.explicit_index) {
+ /* From the GLSL 4.30 specification, section 4.4.2 (Output
+ * Layout Qualifiers):
+ *
+ * "It is also a compile-time error if a fragment shader
+ * sets a layout index to less than 0 or greater than 1."
+ *
+ * Older specifications don't mandate a behavior; we take
+ * this as a clarification and always generate the error.
+ */
+ if (qual->index < 0 || qual->index > 1) {
+ _mesa_glsl_error(loc, state,
+ "explicit index may only be 0 or 1");
+ } else {
+ var->data.explicit_index = true;
+ var->data.index = qual->index;
+ }
+ }
+ }
+
+ return;
+}
+