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/*

 * Copyright © 2014 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.

 *

 * Authors:

 *    Connor Abbott (cwabbott0@gmail.com)

 *    Jason Ekstrand (jason@jlekstrand.net)

 *

 */

/*

 * This lowering pass converts references to input/output variables with

 * loads/stores to actual input/output intrinsics.

 *

 * NOTE: This pass really only works for scalar backends at the moment due

 * to the way it packes the input/output data.

 */

#include "nir.h"

struct lower_io_state {

   void *mem_ctx;

};

static unsigned

type_size(const struct glsl_type *type)

{

   unsigned int size, i;

   switch (glsl_get_base_type(type)) {

   case GLSL_TYPE_UINT:

   case GLSL_TYPE_INT:

   case GLSL_TYPE_FLOAT:

   case GLSL_TYPE_BOOL:

      return glsl_get_components(type);

   case GLSL_TYPE_ARRAY:

      return type_size(glsl_get_array_element(type)) * glsl_get_length(type);

   case GLSL_TYPE_STRUCT:

      size = 0;

      for (i = 0; i < glsl_get_length(type); i++) {

         size += type_size(glsl_get_struct_field(type, i));

      }

      return size;

   case GLSL_TYPE_SAMPLER:

      return 0;

   case GLSL_TYPE_ATOMIC_UINT:

      return 0;

   case GLSL_TYPE_INTERFACE:

      return 0;

   case GLSL_TYPE_IMAGE:

      return 0;

   case GLSL_TYPE_VOID:

   case GLSL_TYPE_ERROR:

   case GLSL_TYPE_DOUBLE:

      unreachable("not reached");

   }

   return 0;

}

void

nir_assign_var_locations_scalar(struct exec_list *var_list, unsigned *size)

{

   unsigned location = 0;

   foreach_list_typed(nir_variable, var, node, var_list) {

      /*

       * UBO's have their own address spaces, so don't count them towards the

       * number of global uniforms

       */

      if (var->data.mode == nir_var_uniform && var->interface_type != NULL)

         continue;

      var->data.driver_location = location;

      location += type_size(var->type);

   }

   *size = location;

}

static bool

deref_has_indirect(nir_deref_var *deref)

{

   for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {

      if (tail->deref_type == nir_deref_type_array) {

         nir_deref_array *arr = nir_deref_as_array(tail);

         if (arr->deref_array_type == nir_deref_array_type_indirect)

            return true;

      }

   }

   return false;

}

static bool

mark_indirect_uses_block(nir_block *block, void *void_state)

{

   struct set *indirect_set = void_state;

   nir_foreach_instr(block, instr) {

      if (instr->type != nir_instr_type_intrinsic)

         continue;

      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);

      for (unsigned i = 0;

           i < nir_intrinsic_infos[intrin->intrinsic].num_variables; i++) {

         if (deref_has_indirect(intrin->variables[i]))

            _mesa_set_add(indirect_set, intrin->variables[i]->var);

      }

   }

   return true;

}

/* Identical to nir_assign_var_locations_packed except that it assigns

 * locations to the variables that are used 100% directly first and then

 * assigns locations to variables that are used indirectly.

 */

void

nir_assign_var_locations_scalar_direct_first(nir_shader *shader,

                                             struct exec_list *var_list,

                                             unsigned *direct_size,

                                             unsigned *size)

{

   struct set *indirect_set = _mesa_set_create(NULL, _mesa_hash_pointer,

                                               _mesa_key_pointer_equal);

   nir_foreach_overload(shader, overload) {

      if (overload->impl)

         nir_foreach_block(overload->impl, mark_indirect_uses_block,

                           indirect_set);

   }

   unsigned location = 0;

   foreach_list_typed(nir_variable, var, node, var_list) {

      if (var->data.mode == nir_var_uniform && var->interface_type != NULL)

         continue;

      if (_mesa_set_search(indirect_set, var))

         continue;

      var->data.driver_location = location;

      location += type_size(var->type);

   }

   *direct_size = location;

   foreach_list_typed(nir_variable, var, node, var_list) {

      if (var->data.mode == nir_var_uniform && var->interface_type != NULL)

         continue;

      if (!_mesa_set_search(indirect_set, var))

         continue;

      var->data.driver_location = location;

      location += type_size(var->type);

   }

   *size = location;

   _mesa_set_destroy(indirect_set, NULL);

}

static unsigned

get_io_offset(nir_deref_var *deref, nir_instr *instr, nir_src *indirect,

              struct lower_io_state *state)

{

   bool found_indirect = false;

   unsigned base_offset = 0;

   nir_deref *tail = &deref->deref;

   while (tail->child != NULL) {

      const struct glsl_type *parent_type = tail->type;

      tail = tail->child;

      if (tail->deref_type == nir_deref_type_array) {

         nir_deref_array *deref_array = nir_deref_as_array(tail);

         unsigned size = type_size(tail->type);

         base_offset += size * deref_array->base_offset;

         if (deref_array->deref_array_type == nir_deref_array_type_indirect) {

            nir_load_const_instr *load_const =

               nir_load_const_instr_create(state->mem_ctx, 1);

            load_const->value.u[0] = size;

            nir_instr_insert_before(instr, &load_const->instr);

            nir_alu_instr *mul = nir_alu_instr_create(state->mem_ctx,

                                                      nir_op_imul);

            mul->src[0].src.is_ssa = true;

            mul->src[0].src.ssa = &load_const->def;

            nir_src_copy(&mul->src[1].src, &deref_array->indirect,

                         state->mem_ctx);

            mul->dest.write_mask = 1;

            nir_ssa_dest_init(&mul->instr, &mul->dest.dest, 1, NULL);

            nir_instr_insert_before(instr, &mul->instr);

            if (found_indirect) {

               nir_alu_instr *add = nir_alu_instr_create(state->mem_ctx,

                                                         nir_op_iadd);

               add->src[0].src = *indirect;

               add->src[1].src.is_ssa = true;

               add->src[1].src.ssa = &mul->dest.dest.ssa;

               add->dest.write_mask = 1;

               nir_ssa_dest_init(&add->instr, &add->dest.dest, 1, NULL);

               nir_instr_insert_before(instr, &add->instr);

               indirect->is_ssa = true;

               indirect->ssa = &add->dest.dest.ssa;

            } else {

               indirect->is_ssa = true;

               indirect->ssa = &mul->dest.dest.ssa;

               found_indirect = true;

            }

         }

      } else if (tail->deref_type == nir_deref_type_struct) {

         nir_deref_struct *deref_struct = nir_deref_as_struct(tail);

         for (unsigned i = 0; i < deref_struct->index; i++)

            base_offset += type_size(glsl_get_struct_field(parent_type, i));

      }

   }

   return base_offset;

}

static bool

nir_lower_io_block(nir_block *block, void *void_state)

{

   struct lower_io_state *state = void_state;

   nir_foreach_instr_safe(block, instr) {

      if (instr->type != nir_instr_type_intrinsic)

         continue;

      nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);

      switch (intrin->intrinsic) {

      case nir_intrinsic_load_var: {

         nir_variable_mode mode = intrin->variables[0]->var->data.mode;

         if (mode != nir_var_shader_in && mode != nir_var_uniform)

            continue;

         bool has_indirect = deref_has_indirect(intrin->variables[0]);

         /* Figure out the opcode */

         nir_intrinsic_op load_op;

         switch (mode) {

         case nir_var_shader_in:

            load_op = has_indirect ? nir_intrinsic_load_input_indirect :

                                     nir_intrinsic_load_input;

            break;

         case nir_var_uniform:

            load_op = has_indirect ? nir_intrinsic_load_uniform_indirect :

                                     nir_intrinsic_load_uniform;

            break;

         default:

            unreachable("Unknown variable mode");

         }

         nir_intrinsic_instr *load = nir_intrinsic_instr_create(state->mem_ctx,

                                                                load_op);

         load->num_components = intrin->num_components;

         nir_src indirect;

         unsigned offset = get_io_offset(intrin->variables[0],

                                         &intrin->instr, &indirect, state);

         offset += intrin->variables[0]->var->data.driver_location;

         load->const_index[0] = offset;

         load->const_index[1] = 1;

         if (has_indirect)

            load->src[0] = indirect;

         if (intrin->dest.is_ssa) {

            nir_ssa_dest_init(&load->instr, &load->dest,

                              intrin->num_components, NULL);

            nir_ssa_def_rewrite_uses(&intrin->dest.ssa,

                                     nir_src_for_ssa(&load->dest.ssa),

                                     state->mem_ctx);

         } else {

            nir_dest_copy(&load->dest, &intrin->dest, state->mem_ctx);

         }

         nir_instr_insert_before(&intrin->instr, &load->instr);

         nir_instr_remove(&intrin->instr);

         break;

      }

      case nir_intrinsic_store_var: {

         if (intrin->variables[0]->var->data.mode != nir_var_shader_out)

            continue;

         bool has_indirect = deref_has_indirect(intrin->variables[0]);

         nir_intrinsic_op store_op;

         if (has_indirect) {

            store_op = nir_intrinsic_store_output_indirect;

         } else {

            store_op = nir_intrinsic_store_output;

         }

         nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,

                                                                 store_op);

         store->num_components = intrin->num_components;

         nir_src indirect;

         unsigned offset = get_io_offset(intrin->variables[0],

                                         &intrin->instr, &indirect, state);

         offset += intrin->variables[0]->var->data.driver_location;

         store->const_index[0] = offset;

         store->const_index[1] = 1;

         nir_src_copy(&store->src[0], &intrin->src[0], state->mem_ctx);

         if (has_indirect)

            store->src[1] = indirect;

         nir_instr_insert_before(&intrin->instr, &store->instr);

         nir_instr_remove(&intrin->instr);

         break;

      }

      default:

         break;

      }

   }

   return true;

}

static void

nir_lower_io_impl(nir_function_impl *impl)

{

   struct lower_io_state state;

   state.mem_ctx = ralloc_parent(impl);

   nir_foreach_block(impl, nir_lower_io_block, &state);

   nir_metadata_preserve(impl, nir_metadata_block_index |

                               nir_metadata_dominance);

}

void

nir_lower_io(nir_shader *shader)

{

   nir_foreach_overload(shader, overload) {

      if (overload->impl)

         nir_lower_io_impl(overload->impl);

   }

}