src/glsl/nir/nir_lower_io.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Connor Abbott (cwabbott0@gmail.com)
  25  *    Jason Ekstrand (jason@jlekstrand.net)
  26  *
  27  */
  28
  29 /*
  30  * This lowering pass converts references to input/output variables with
  31  * loads/stores to actual input/output intrinsics.
  32  */
  33
  34 #include "nir.h"
  35 #include "nir_builder.h"
  36
  37 struct lower_io_state {
  38    nir_builder builder;
  39    void *mem_ctx;
  40    int (*type_size)(const struct glsl_type *type);
  41    nir_variable_mode mode;
  42 };
  43
  44 void
  45 nir_assign_var_locations(struct exec_list *var_list, unsigned *size,
  46                          int (*type_size)(const struct glsl_type *))
  47 {
  48    unsigned location = 0;
  49
  50    foreach_list_typed(nir_variable, var, node, var_list) {
  51       /*
  52        * UBO's have their own address spaces, so don't count them towards the
  53        * number of global uniforms
  54        */
  55       if ((var->data.mode == nir_var_uniform || var->data.mode == nir_var_shader_storage) &&
  56           var->interface_type != NULL)
  57          continue;
  58
  59       var->data.driver_location = location;
  60       location += type_size(var->type);
  61    }
  62
  63    *size = location;
  64 }
  65
  66 static bool
  67 deref_has_indirect(nir_deref_var *deref)
  68 {
  69    for (nir_deref *tail = deref->deref.child; tail; tail = tail->child) {
  70       if (tail->deref_type == nir_deref_type_array) {
  71          nir_deref_array *arr = nir_deref_as_array(tail);
  72          if (arr->deref_array_type == nir_deref_array_type_indirect)
  73             return true;
  74       }
  75    }
  76
  77    return false;
  78 }
  79
  80 static unsigned
  81 get_io_offset(nir_deref_var *deref, nir_instr *instr, nir_src *indirect,
  82               struct lower_io_state *state)
  83 {
  84    bool found_indirect = false;
  85    unsigned base_offset = 0;
  86
  87    nir_builder *b = &state->builder;
  88    b->cursor = nir_before_instr(instr);
  89
  90    nir_deref *tail = &deref->deref;
  91    while (tail->child != NULL) {
  92       const struct glsl_type *parent_type = tail->type;
  93       tail = tail->child;
  94
  95       if (tail->deref_type == nir_deref_type_array) {
  96          nir_deref_array *deref_array = nir_deref_as_array(tail);
  97          unsigned size = state->type_size(tail->type);
  98
  99          base_offset += size * deref_array->base_offset;
 100
 101          if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
 102             nir_ssa_def *mul =
 103                nir_imul(b, nir_imm_int(b, size),
 104                         nir_ssa_for_src(b, deref_array->indirect, 1));
 105
 106             if (found_indirect) {
 107                indirect->ssa =
 108                   nir_iadd(b, nir_ssa_for_src(b, *indirect, 1), mul);
 109             } else {
 110                indirect->ssa = mul;
 111             }
 112             indirect->is_ssa = true;
 113             found_indirect = true;
 114          }
 115       } else if (tail->deref_type == nir_deref_type_struct) {
 116          nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
 117
 118          for (unsigned i = 0; i < deref_struct->index; i++) {
 119             base_offset +=
 120                state->type_size(glsl_get_struct_field(parent_type, i));
 121          }
 122       }
 123    }
 124
 125    return base_offset;
 126 }
 127
 128 static nir_intrinsic_op
 129 load_op(nir_variable_mode mode, bool has_indirect)
 130 {
 131    nir_intrinsic_op op;
 132    switch (mode) {
 133    case nir_var_shader_in:
 134       op = has_indirect ? nir_intrinsic_load_input_indirect :
 135                           nir_intrinsic_load_input;
 136       break;
 137    case nir_var_uniform:
 138       op = has_indirect ? nir_intrinsic_load_uniform_indirect :
 139                           nir_intrinsic_load_uniform;
 140       break;
 141    default:
 142       unreachable("Unknown variable mode");
 143    }
 144    return op;
 145 }
 146
 147 static bool
 148 nir_lower_io_block(nir_block *block, void *void_state)
 149 {
 150    struct lower_io_state *state = void_state;
 151
 152    nir_foreach_instr_safe(block, instr) {
 153       if (instr->type != nir_instr_type_intrinsic)
 154          continue;
 155
 156       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
 157
 158       if (intrin->intrinsic != nir_intrinsic_load_var &&
 159           intrin->intrinsic != nir_intrinsic_store_var)
 160          continue;
 161
 162       nir_variable_mode mode = intrin->variables[0]->var->data.mode;
 163
 164       if (state->mode != -1 && state->mode != mode)
 165          continue;
 166
 167       switch (intrin->intrinsic) {
 168       case nir_intrinsic_load_var: {
 169          if (mode != nir_var_shader_in && mode != nir_var_uniform)
 170             continue;
 171
 172          bool has_indirect = deref_has_indirect(intrin->variables[0]);
 173
 174          nir_intrinsic_instr *load =
 175             nir_intrinsic_instr_create(state->mem_ctx,
 176                                        load_op(mode, has_indirect));
 177          load->num_components = intrin->num_components;
 178
 179          nir_src indirect;
 180          unsigned offset = get_io_offset(intrin->variables[0],
 181                                          &intrin->instr, &indirect, state);
 182
 183          unsigned location = intrin->variables[0]->var->data.driver_location;
 184          if (mode == nir_var_uniform) {
 185             load->const_index[0] = location;
 186             load->const_index[1] = offset;
 187          } else {
 188             load->const_index[0] = location + offset;
 189          }
 190
 191          if (has_indirect)
 192             load->src[0] = indirect;
 193
 194          if (intrin->dest.is_ssa) {
 195             nir_ssa_dest_init(&load->instr, &load->dest,
 196                               intrin->num_components, NULL);
 197             nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
 198                                      nir_src_for_ssa(&load->dest.ssa));
 199          } else {
 200             nir_dest_copy(&load->dest, &intrin->dest, state->mem_ctx);
 201          }
 202
 203          nir_instr_insert_before(&intrin->instr, &load->instr);
 204          nir_instr_remove(&intrin->instr);
 205          break;
 206       }
 207
 208       case nir_intrinsic_store_var: {
 209          if (intrin->variables[0]->var->data.mode != nir_var_shader_out)
 210             continue;
 211
 212          bool has_indirect = deref_has_indirect(intrin->variables[0]);
 213
 214          nir_intrinsic_op store_op;
 215          if (has_indirect) {
 216             store_op = nir_intrinsic_store_output_indirect;
 217          } else {
 218             store_op = nir_intrinsic_store_output;
 219          }
 220
 221          nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,
 222                                                                  store_op);
 223          store->num_components = intrin->num_components;
 224
 225          nir_src indirect;
 226          unsigned offset = get_io_offset(intrin->variables[0],
 227                                          &intrin->instr, &indirect, state);
 228          offset += intrin->variables[0]->var->data.driver_location;
 229
 230          store->const_index[0] = offset;
 231
 232          nir_src_copy(&store->src[0], &intrin->src[0], store);
 233
 234          if (has_indirect)
 235             store->src[1] = indirect;
 236
 237          nir_instr_insert_before(&intrin->instr, &store->instr);
 238          nir_instr_remove(&intrin->instr);
 239          break;
 240       }
 241
 242       default:
 243          break;
 244       }
 245    }
 246
 247    return true;
 248 }
 249
 250 static void
 251 nir_lower_io_impl(nir_function_impl *impl,
 252                   nir_variable_mode mode,
 253                   int (*type_size)(const struct glsl_type *))
 254 {
 255    struct lower_io_state state;
 256
 257    nir_builder_init(&state.builder, impl);
 258    state.mem_ctx = ralloc_parent(impl);
 259    state.mode = mode;
 260    state.type_size = type_size;
 261
 262    nir_foreach_block(impl, nir_lower_io_block, &state);
 263
 264    nir_metadata_preserve(impl, nir_metadata_block_index |
 265                                nir_metadata_dominance);
 266 }
 267
 268 void
 269 nir_lower_io(nir_shader *shader, nir_variable_mode mode,
 270              int (*type_size)(const struct glsl_type *))
 271 {
 272    nir_foreach_overload(shader, overload) {
 273       if (overload->impl)
 274          nir_lower_io_impl(overload->impl, mode, type_size);
 275    }
 276 }