/*
 * Copyright © 2013 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "link_uniform_block_active_visitor.h"
#include "program.h"

link_uniform_block_active *
process_block(void *mem_ctx, struct hash_table *ht, ir_variable *var)
{
   const uint32_t h = _mesa_hash_string(var->get_interface_type()->name);
   const hash_entry *const existing_block =
      _mesa_hash_table_search(ht, h, var->get_interface_type()->name);

   const glsl_type *const block_type = var->is_interface_instance()
      ? var->type : var->get_interface_type();


   /* If a block with this block-name has not previously been seen, add it.
    * If a block with this block-name has been seen, it must be identical to
    * the block currently being examined.
    */
   if (existing_block == NULL) {
      link_uniform_block_active *const b =
	 rzalloc(mem_ctx, struct link_uniform_block_active);

      b->type = block_type;
      b->has_instance_name = var->is_interface_instance();

      if (var->data.explicit_binding) {
         b->has_binding = true;
         b->binding = var->data.binding;
      } else {
         b->has_binding = false;
         b->binding = 0;
      }

      _mesa_hash_table_insert(ht, h, var->get_interface_type()->name,
			      (void *) b);
      return b;
   } else {
      link_uniform_block_active *const b =
	 (link_uniform_block_active *) existing_block->data;

      if (b->type != block_type
	  || b->has_instance_name != var->is_interface_instance())
	 return NULL;
      else
	 return b;
   }

   assert(!"Should not get here.");
   return NULL;
}

ir_visitor_status
link_uniform_block_active_visitor::visit_enter(ir_dereference_array *ir)
{
   ir_dereference_variable *const d = ir->array->as_dereference_variable();
   ir_variable *const var = (d == NULL) ? NULL : d->var;

   /* If the r-value being dereferenced is not a variable (e.g., a field of a
    * structure) or is not a uniform block instance, continue.
    *
    * WARNING: It is not enough for the variable to be part of uniform block.
    * It must represent the entire block.  Arrays (or matrices) inside blocks
    * that lack an instance name are handled by the ir_dereference_variable
    * function.
    */
   if (var == NULL
       || !var->is_in_uniform_block()
       || !var->is_interface_instance())
      return visit_continue;

   /* Process the block.  Bail if there was an error.
    */
   link_uniform_block_active *const b =
      process_block(this->mem_ctx, this->ht, var);
   if (b == NULL) {
      linker_error(prog,
		   "uniform block `%s' has mismatching definitions",
		   var->get_interface_type()->name);
      this->success = false;
      return visit_stop;
   }

   /* Block arrays must be declared with an instance name.
    */
   assert(b->has_instance_name);
   assert((b->num_array_elements == 0) == (b->array_elements == NULL));
   assert(b->type != NULL);

   /* Determine whether or not this array index has already been added to the
    * list of active array indices.  At this point all constant folding must
    * have occurred, and the array index must be a constant.
    */
   ir_constant *c = ir->array_index->as_constant();
   assert(c != NULL);

   const unsigned idx = c->get_uint_component(0);

   unsigned i;
   for (i = 0; i < b->num_array_elements; i++) {
      if (b->array_elements[i] == idx)
	 break;
   }

   assert(i <= b->num_array_elements);

   if (i == b->num_array_elements) {
      b->array_elements = reralloc(this->mem_ctx,
				   b->array_elements,
				   unsigned,
				   b->num_array_elements + 1);

      b->array_elements[b->num_array_elements] = idx;

      b->num_array_elements++;
   }

   return visit_continue_with_parent;
}

ir_visitor_status
link_uniform_block_active_visitor::visit(ir_dereference_variable *ir)
{
   ir_variable *var = ir->var;

   if (!var->is_in_uniform_block())
      return visit_continue;

   assert(!var->is_interface_instance() || !var->type->is_array());

   /* Process the block.  Bail if there was an error.
    */
   link_uniform_block_active *const b =
      process_block(this->mem_ctx, this->ht, var);
   if (b == NULL) {
      linker_error(this->prog,
		   "uniform block `%s' has mismatching definitions",
		   var->get_interface_type()->name);
      this->success = false;
      return visit_stop;
   }

   assert(b->num_array_elements == 0);
   assert(b->array_elements == NULL);
   assert(b->type != NULL);

   return visit_continue;
}