+namespace linker {
+
+bool
+populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
+ hash_table *consumer_inputs,
+ hash_table *consumer_interface_inputs,
+ ir_variable *consumer_inputs_with_locations[VARYING_SLOT_MAX])
+{
+ memset(consumer_inputs_with_locations,
+ 0,
+ sizeof(consumer_inputs_with_locations[0]) * VARYING_SLOT_MAX);
+
+ foreach_list(node, ir) {
+ ir_variable *const input_var = ((ir_instruction *) node)->as_variable();
+
+ if ((input_var != NULL) && (input_var->data.mode == ir_var_shader_in)) {
+ if (input_var->type->is_interface())
+ return false;
+
+ if (input_var->data.explicit_location) {
+ /* assign_varying_locations only cares about finding the
+ * ir_variable at the start of a contiguous location block.
+ *
+ * - For !producer, consumer_inputs_with_locations isn't used.
+ *
+ * - For !consumer, consumer_inputs_with_locations is empty.
+ *
+ * For consumer && producer, if you were trying to set some
+ * ir_variable to the middle of a location block on the other side
+ * of producer/consumer, cross_validate_outputs_to_inputs() should
+ * be link-erroring due to either type mismatch or location
+ * overlaps. If the variables do match up, then they've got a
+ * matching data.location and you only looked at
+ * consumer_inputs_with_locations[var->data.location], not any
+ * following entries for the array/structure.
+ */
+ consumer_inputs_with_locations[input_var->data.location] =
+ input_var;
+ } else if (input_var->get_interface_type() != NULL) {
+ char *const iface_field_name =
+ ralloc_asprintf(mem_ctx, "%s.%s",
+ input_var->get_interface_type()->name,
+ input_var->name);
+ hash_table_insert(consumer_interface_inputs, input_var,
+ iface_field_name);
+ } else {
+ hash_table_insert(consumer_inputs, input_var,
+ ralloc_strdup(mem_ctx, input_var->name));
+ }
+ }
+ }
+
+ return true;
+}
+
+/**
+ * Find a variable from the consumer that "matches" the specified variable
+ *
+ * This function only finds inputs with names that match. There is no
+ * validation (here) that the types, etc. are compatible.
+ */
+ir_variable *
+get_matching_input(void *mem_ctx,
+ const ir_variable *output_var,
+ hash_table *consumer_inputs,
+ hash_table *consumer_interface_inputs,
+ ir_variable *consumer_inputs_with_locations[VARYING_SLOT_MAX])
+{
+ ir_variable *input_var;
+
+ if (output_var->data.explicit_location) {
+ input_var = consumer_inputs_with_locations[output_var->data.location];
+ } else if (output_var->get_interface_type() != NULL) {
+ char *const iface_field_name =
+ ralloc_asprintf(mem_ctx, "%s.%s",
+ output_var->get_interface_type()->name,
+ output_var->name);
+ input_var =
+ (ir_variable *) hash_table_find(consumer_interface_inputs,
+ iface_field_name);
+ } else {
+ input_var =
+ (ir_variable *) hash_table_find(consumer_inputs, output_var->name);
+ }
+
+ return (input_var == NULL || input_var->data.mode != ir_var_shader_in)
+ ? NULL : input_var;
+}
+
+}
+
+static int
+io_variable_cmp(const void *_a, const void *_b)
+{
+ const ir_variable *const a = *(const ir_variable **) _a;
+ const ir_variable *const b = *(const ir_variable **) _b;
+
+ if (a->data.explicit_location && b->data.explicit_location)
+ return b->data.location - a->data.location;
+
+ if (a->data.explicit_location && !b->data.explicit_location)
+ return 1;
+
+ if (!a->data.explicit_location && b->data.explicit_location)
+ return -1;
+
+ return -strcmp(a->name, b->name);
+}
+
+/**
+ * Sort the shader IO variables into canonical order
+ */
+static void
+canonicalize_shader_io(exec_list *ir, enum ir_variable_mode io_mode)
+{
+ ir_variable *var_table[MAX_PROGRAM_OUTPUTS * 4];
+ unsigned num_variables = 0;
+
+ foreach_list(node, ir) {
+ ir_variable *const var = ((ir_instruction *) node)->as_variable();
+
+ if (var == NULL || var->data.mode != io_mode)
+ continue;
+
+ /* If we have already encountered more I/O variables that could
+ * successfully link, bail.
+ */
+ if (num_variables == ARRAY_SIZE(var_table))
+ return;
+
+ var_table[num_variables++] = var;
+ }
+
+ if (num_variables == 0)
+ return;
+
+ /* Sort the list in reverse order (io_variable_cmp handles this). Later
+ * we're going to push the variables on to the IR list as a stack, so we
+ * want the last variable (in canonical order) to be first in the list.
+ */
+ qsort(var_table, num_variables, sizeof(var_table[0]), io_variable_cmp);
+
+ /* Remove the variable from it's current location in the IR, and put it at
+ * the front.
+ */
+ for (unsigned i = 0; i < num_variables; i++) {
+ var_table[i]->remove();
+ ir->push_head(var_table[i]);
+ }
+}
+