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    nir_foreach_variable(var, 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 /**
  67  * Returns true if we're processing a stage whose inputs are arrays indexed
  68  * by a vertex number (such as geometry shader inputs).
  69  */
  70 static bool
  71 is_per_vertex_input(struct lower_io_state *state, nir_variable *var)
  72 {
  73    gl_shader_stage stage = state->builder.shader->stage;
  74
  75    return var->data.mode == nir_var_shader_in && !var->data.patch &&
  76           (stage == MESA_SHADER_TESS_CTRL ||
  77            stage == MESA_SHADER_TESS_EVAL ||
  78            stage == MESA_SHADER_GEOMETRY);
  79 }
  80
  81 static bool
  82 is_per_vertex_output(struct lower_io_state *state, nir_variable *var)
  83 {
  84    gl_shader_stage stage = state->builder.shader->stage;
  85    return var->data.mode == nir_var_shader_out && !var->data.patch &&
  86           stage == MESA_SHADER_TESS_CTRL;
  87 }
  88
  89 static unsigned
  90 get_io_offset(nir_deref_var *deref, nir_instr *instr,
  91               nir_ssa_def **vertex_index,
  92               nir_ssa_def **out_indirect,
  93               struct lower_io_state *state)
  94 {
  95    nir_ssa_def *indirect = NULL;
  96    unsigned base_offset = 0;
  97
  98    nir_builder *b = &state->builder;
  99    b->cursor = nir_before_instr(instr);
 100
 101    nir_deref *tail = &deref->deref;
 102
 103    /* For per-vertex input arrays (i.e. geometry shader inputs), keep the
 104     * outermost array index separate.  Process the rest normally.
 105     */
 106    if (vertex_index != NULL) {
 107       tail = tail->child;
 108       assert(tail->deref_type == nir_deref_type_array);
 109       nir_deref_array *deref_array = nir_deref_as_array(tail);
 110
 111       nir_ssa_def *vtx = nir_imm_int(b, deref_array->base_offset);
 112       if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
 113          vtx = nir_iadd(b, vtx, nir_ssa_for_src(b, deref_array->indirect, 1));
 114       }
 115       *vertex_index = vtx;
 116    }
 117
 118    while (tail->child != NULL) {
 119       const struct glsl_type *parent_type = tail->type;
 120       tail = tail->child;
 121
 122       if (tail->deref_type == nir_deref_type_array) {
 123          nir_deref_array *deref_array = nir_deref_as_array(tail);
 124          unsigned size = state->type_size(tail->type);
 125
 126          base_offset += size * deref_array->base_offset;
 127
 128          if (deref_array->deref_array_type == nir_deref_array_type_indirect) {
 129             nir_ssa_def *mul =
 130                nir_imul(b, nir_imm_int(b, size),
 131                         nir_ssa_for_src(b, deref_array->indirect, 1));
 132
 133             indirect = indirect ? nir_iadd(b, indirect, mul) : mul;
 134          }
 135       } else if (tail->deref_type == nir_deref_type_struct) {
 136          nir_deref_struct *deref_struct = nir_deref_as_struct(tail);
 137
 138          for (unsigned i = 0; i < deref_struct->index; i++) {
 139             base_offset +=
 140                state->type_size(glsl_get_struct_field(parent_type, i));
 141          }
 142       }
 143    }
 144
 145    *out_indirect = indirect;
 146    return base_offset;
 147 }
 148
 149 static nir_intrinsic_op
 150 load_op(struct lower_io_state *state,
 151         nir_variable_mode mode, bool per_vertex, bool has_indirect)
 152 {
 153    nir_intrinsic_op op;
 154    switch (mode) {
 155    case nir_var_shader_in:
 156       if (per_vertex) {
 157          op = has_indirect ? nir_intrinsic_load_per_vertex_input_indirect :
 158                              nir_intrinsic_load_per_vertex_input;
 159       } else {
 160          op = has_indirect ? nir_intrinsic_load_input_indirect :
 161                              nir_intrinsic_load_input;
 162       }
 163       break;
 164    case nir_var_shader_out:
 165       if (per_vertex) {
 166          op = has_indirect ? nir_intrinsic_load_per_vertex_output_indirect :
 167                              nir_intrinsic_load_per_vertex_output;
 168       } else {
 169          op = has_indirect ? nir_intrinsic_load_output_indirect :
 170                              nir_intrinsic_load_output;
 171       }
 172       break;
 173    case nir_var_uniform:
 174       op = has_indirect ? nir_intrinsic_load_uniform_indirect :
 175                           nir_intrinsic_load_uniform;
 176       break;
 177    default:
 178       unreachable("Unknown variable mode");
 179    }
 180    return op;
 181 }
 182
 183 static bool
 184 nir_lower_io_block(nir_block *block, void *void_state)
 185 {
 186    struct lower_io_state *state = void_state;
 187
 188    nir_foreach_instr_safe(block, instr) {
 189       if (instr->type != nir_instr_type_intrinsic)
 190          continue;
 191
 192       nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
 193
 194       if (intrin->intrinsic != nir_intrinsic_load_var &&
 195           intrin->intrinsic != nir_intrinsic_store_var)
 196          continue;
 197
 198       nir_variable_mode mode = intrin->variables[0]->var->data.mode;
 199
 200       if (state->mode != nir_var_all && state->mode != mode)
 201          continue;
 202
 203       if (mode != nir_var_shader_in &&
 204           mode != nir_var_shader_out &&
 205           mode != nir_var_uniform)
 206          continue;
 207
 208       switch (intrin->intrinsic) {
 209       case nir_intrinsic_load_var: {
 210          bool per_vertex =
 211             is_per_vertex_input(state, intrin->variables[0]->var) ||
 212             is_per_vertex_output(state, intrin->variables[0]->var);
 213
 214          nir_ssa_def *indirect;
 215          nir_ssa_def *vertex_index;
 216
 217          unsigned offset = get_io_offset(intrin->variables[0], &intrin->instr,
 218                                          per_vertex ? &vertex_index : NULL,
 219                                          &indirect, state);
 220
 221          nir_intrinsic_instr *load =
 222             nir_intrinsic_instr_create(state->mem_ctx,
 223                                        load_op(state, mode, per_vertex,
 224                                                indirect));
 225          load->num_components = intrin->num_components;
 226
 227          unsigned location = intrin->variables[0]->var->data.driver_location;
 228          if (mode == nir_var_uniform) {
 229             load->const_index[0] = location;
 230             load->const_index[1] = offset;
 231          } else {
 232             load->const_index[0] = location + offset;
 233          }
 234
 235          if (per_vertex)
 236             load->src[0] = nir_src_for_ssa(vertex_index);
 237
 238          if (indirect)
 239             load->src[per_vertex ? 1 : 0] = nir_src_for_ssa(indirect);
 240
 241          if (intrin->dest.is_ssa) {
 242             nir_ssa_dest_init(&load->instr, &load->dest,
 243                               intrin->num_components, NULL);
 244             nir_ssa_def_rewrite_uses(&intrin->dest.ssa,
 245                                      nir_src_for_ssa(&load->dest.ssa));
 246          } else {
 247             nir_dest_copy(&load->dest, &intrin->dest, state->mem_ctx);
 248          }
 249
 250          nir_instr_insert_before(&intrin->instr, &load->instr);
 251          nir_instr_remove(&intrin->instr);
 252          break;
 253       }
 254
 255       case nir_intrinsic_store_var: {
 256          assert(mode == nir_var_shader_out);
 257
 258          nir_ssa_def *indirect;
 259          nir_ssa_def *vertex_index;
 260
 261          bool per_vertex =
 262             is_per_vertex_output(state, intrin->variables[0]->var);
 263
 264          unsigned offset = get_io_offset(intrin->variables[0], &intrin->instr,
 265                                          per_vertex ? &vertex_index : NULL,
 266                                          &indirect, state);
 267          offset += intrin->variables[0]->var->data.driver_location;
 268
 269          nir_intrinsic_op store_op;
 270          if (per_vertex) {
 271             store_op = indirect ? nir_intrinsic_store_per_vertex_output_indirect
 272                                 : nir_intrinsic_store_per_vertex_output;
 273          } else {
 274             store_op = indirect ? nir_intrinsic_store_output_indirect
 275                                 : nir_intrinsic_store_output;
 276          }
 277
 278          nir_intrinsic_instr *store = nir_intrinsic_instr_create(state->mem_ctx,
 279                                                                  store_op);
 280          store->num_components = intrin->num_components;
 281          store->const_index[0] = offset;
 282
 283          nir_src_copy(&store->src[0], &intrin->src[0], store);
 284
 285          if (per_vertex)
 286             store->src[1] = nir_src_for_ssa(vertex_index);
 287
 288          if (indirect)
 289             store->src[per_vertex ? 2 : 1] = nir_src_for_ssa(indirect);
 290
 291          nir_instr_insert_before(&intrin->instr, &store->instr);
 292          nir_instr_remove(&intrin->instr);
 293          break;
 294       }
 295
 296       default:
 297          break;
 298       }
 299    }
 300
 301    return true;
 302 }
 303
 304 static void
 305 nir_lower_io_impl(nir_function_impl *impl,
 306                   nir_variable_mode mode,
 307                   int (*type_size)(const struct glsl_type *))
 308 {
 309    struct lower_io_state state;
 310
 311    nir_builder_init(&state.builder, impl);
 312    state.mem_ctx = ralloc_parent(impl);
 313    state.mode = mode;
 314    state.type_size = type_size;
 315
 316    nir_foreach_block(impl, nir_lower_io_block, &state);
 317
 318    nir_metadata_preserve(impl, nir_metadata_block_index |
 319                                nir_metadata_dominance);
 320 }
 321
 322 void
 323 nir_lower_io(nir_shader *shader, nir_variable_mode mode,
 324              int (*type_size)(const struct glsl_type *))
 325 {
 326    nir_foreach_overload(shader, overload) {
 327       if (overload->impl)
 328          nir_lower_io_impl(overload->impl, mode, type_size);
 329    }
 330 }
 331
 332 /**
 333  * Return the indirect source for a load/store indirect intrinsic.
 334  */
 335 nir_src *
 336 nir_get_io_indirect_src(nir_intrinsic_instr *instr)
 337 {
 338    switch (instr->intrinsic) {
 339    case nir_intrinsic_load_input_indirect:
 340    case nir_intrinsic_load_output_indirect:
 341    case nir_intrinsic_load_uniform_indirect:
 342       return &instr->src[0];
 343    case nir_intrinsic_load_per_vertex_input_indirect:
 344    case nir_intrinsic_load_per_vertex_output_indirect:
 345    case nir_intrinsic_store_output_indirect:
 346       return &instr->src[1];
 347    case nir_intrinsic_store_per_vertex_output_indirect:
 348       return &instr->src[2];
 349    default:
 350       return NULL;
 351    }
 352 }
 353
 354 /**
 355  * Return the vertex index source for a load/store per_vertex intrinsic.
 356  */
 357 nir_src *
 358 nir_get_io_vertex_index_src(nir_intrinsic_instr *instr)
 359 {
 360    switch (instr->intrinsic) {
 361    case nir_intrinsic_load_per_vertex_input:
 362    case nir_intrinsic_load_per_vertex_output:
 363    case nir_intrinsic_load_per_vertex_input_indirect:
 364    case nir_intrinsic_load_per_vertex_output_indirect:
 365       return &instr->src[0];
 366    case nir_intrinsic_store_per_vertex_output:
 367    case nir_intrinsic_store_per_vertex_output_indirect:
 368       return &instr->src[1];
 369    default:
 370       return NULL;
 371    }
 372 }