src/compiler/nir/nir_lower_system_values.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  *
  26  */
  27
  28 #include "nir.h"
  29 #include "nir_builder.h"
  30
  31 static bool
  32 convert_block(nir_block *block, nir_builder *b)
  33 {
  34    bool progress = false;
  35
  36    nir_foreach_instr_safe(instr, block) {
  37       if (instr->type != nir_instr_type_intrinsic)
  38          continue;
  39
  40       nir_intrinsic_instr *load_deref = nir_instr_as_intrinsic(instr);
  41       if (load_deref->intrinsic != nir_intrinsic_load_deref)
  42          continue;
  43
  44       nir_variable *var =
  45          nir_deref_instr_get_variable(nir_src_as_deref(load_deref->src[0]));
  46
  47       if (var->data.mode != nir_var_system_value)
  48          continue;
  49
  50       b->cursor = nir_after_instr(&load_deref->instr);
  51
  52       nir_ssa_def *sysval = NULL;
  53       switch (var->data.location) {
  54       case SYSTEM_VALUE_GLOBAL_INVOCATION_ID: {
  55          /* From the GLSL man page for gl_GlobalInvocationID:
  56           *
  57           *    "The value of gl_GlobalInvocationID is equal to
  58           *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID"
  59           */
  60
  61          nir_const_value local_size;
  62          memset(&local_size, 0, sizeof(local_size));
  63          local_size.u32[0] = b->shader->info.cs.local_size[0];
  64          local_size.u32[1] = b->shader->info.cs.local_size[1];
  65          local_size.u32[2] = b->shader->info.cs.local_size[2];
  66
  67          nir_ssa_def *group_id = nir_load_work_group_id(b);
  68          nir_ssa_def *local_id = nir_load_local_invocation_id(b);
  69
  70          sysval = nir_iadd(b, nir_imul(b, group_id,
  71                                        nir_build_imm(b, 3, 32, local_size)),
  72                               local_id);
  73          break;
  74       }
  75
  76       case SYSTEM_VALUE_LOCAL_INVOCATION_INDEX: {
  77          /* If lower_cs_local_index_from_id is true, then we derive the local
  78           * index from the local id.
  79           */
  80          if (!b->shader->options->lower_cs_local_index_from_id)
  81             break;
  82
  83          /* From the GLSL man page for gl_LocalInvocationIndex:
  84           *
  85           *    "The value of gl_LocalInvocationIndex is equal to
  86           *    gl_LocalInvocationID.z * gl_WorkGroupSize.x *
  87           *    gl_WorkGroupSize.y + gl_LocalInvocationID.y *
  88           *    gl_WorkGroupSize.x + gl_LocalInvocationID.x"
  89           */
  90          nir_ssa_def *local_id = nir_load_local_invocation_id(b);
  91
  92          nir_ssa_def *size_x =
  93             nir_imm_int(b, b->shader->info.cs.local_size[0]);
  94          nir_ssa_def *size_y =
  95             nir_imm_int(b, b->shader->info.cs.local_size[1]);
  96
  97          sysval = nir_imul(b, nir_channel(b, local_id, 2),
  98                               nir_imul(b, size_x, size_y));
  99          sysval = nir_iadd(b, sysval,
 100                               nir_imul(b, nir_channel(b, local_id, 1), size_x));
 101          sysval = nir_iadd(b, sysval, nir_channel(b, local_id, 0));
 102          break;
 103       }
 104
 105       case SYSTEM_VALUE_LOCAL_GROUP_SIZE: {
 106          nir_const_value local_size;
 107          memset(&local_size, 0, sizeof(local_size));
 108          local_size.u32[0] = b->shader->info.cs.local_size[0];
 109          local_size.u32[1] = b->shader->info.cs.local_size[1];
 110          local_size.u32[2] = b->shader->info.cs.local_size[2];
 111          sysval = nir_build_imm(b, 3, 32, local_size);
 112          break;
 113       }
 114
 115       case SYSTEM_VALUE_VERTEX_ID:
 116          if (b->shader->options->vertex_id_zero_based) {
 117             sysval = nir_iadd(b,
 118                               nir_load_vertex_id_zero_base(b),
 119                               nir_load_first_vertex(b));
 120          } else {
 121             sysval = nir_load_vertex_id(b);
 122          }
 123          break;
 124
 125       case SYSTEM_VALUE_BASE_VERTEX:
 126          /**
 127           * From the OpenGL 4.6 (11.1.3.9 Shader Inputs) specification:
 128           *
 129           * "gl_BaseVertex holds the integer value passed to the baseVertex
 130           * parameter to the command that resulted in the current shader
 131           * invocation. In the case where the command has no baseVertex
 132           * parameter, the value of gl_BaseVertex is zero."
 133           */
 134          if (b->shader->options->lower_base_vertex)
 135             sysval = nir_iand(b,
 136                               nir_load_is_indexed_draw(b),
 137                               nir_load_first_vertex(b));
 138          break;
 139
 140       case SYSTEM_VALUE_INSTANCE_INDEX:
 141          sysval = nir_iadd(b,
 142                            nir_load_instance_id(b),
 143                            nir_load_base_instance(b));
 144          break;
 145
 146       case SYSTEM_VALUE_SUBGROUP_EQ_MASK:
 147       case SYSTEM_VALUE_SUBGROUP_GE_MASK:
 148       case SYSTEM_VALUE_SUBGROUP_GT_MASK:
 149       case SYSTEM_VALUE_SUBGROUP_LE_MASK:
 150       case SYSTEM_VALUE_SUBGROUP_LT_MASK: {
 151          nir_intrinsic_op op =
 152             nir_intrinsic_from_system_value(var->data.location);
 153          nir_intrinsic_instr *load = nir_intrinsic_instr_create(b->shader, op);
 154          nir_ssa_dest_init_for_type(&load->instr, &load->dest,
 155                                     var->type, NULL);
 156          load->num_components = load->dest.ssa.num_components;
 157          nir_builder_instr_insert(b, &load->instr);
 158          sysval = &load->dest.ssa;
 159          break;
 160       }
 161
 162       case SYSTEM_VALUE_DEVICE_INDEX:
 163          if (b->shader->options->lower_device_index_to_zero)
 164             sysval = nir_imm_int(b, 0);
 165          break;
 166
 167       default:
 168          break;
 169       }
 170
 171       if (sysval == NULL) {
 172          nir_intrinsic_op sysval_op =
 173             nir_intrinsic_from_system_value(var->data.location);
 174          sysval = nir_load_system_value(b, sysval_op, 0);
 175       }
 176
 177       nir_ssa_def_rewrite_uses(&load_deref->dest.ssa, nir_src_for_ssa(sysval));
 178       nir_instr_remove(&load_deref->instr);
 179
 180       progress = true;
 181    }
 182
 183    return progress;
 184 }
 185
 186 static bool
 187 convert_impl(nir_function_impl *impl)
 188 {
 189    bool progress = false;
 190    nir_builder builder;
 191    nir_builder_init(&builder, impl);
 192
 193    nir_foreach_block(block, impl) {
 194       progress |= convert_block(block, &builder);
 195    }
 196
 197    nir_metadata_preserve(impl, nir_metadata_block_index |
 198                                nir_metadata_dominance);
 199    return progress;
 200 }
 201
 202 bool
 203 nir_lower_system_values(nir_shader *shader)
 204 {
 205    bool progress = false;
 206
 207    nir_assert_unlowered_derefs(shader, nir_lower_load_store_derefs);
 208
 209    nir_foreach_function(function, shader) {
 210       if (function->impl)
 211          progress = convert_impl(function->impl) || progress;
 212    }
 213
 214    /* We're going to delete the variables so we need to clean up all those
 215     * derefs we left lying around.
 216     */
 217    nir_remove_dead_derefs(shader);
 218
 219    exec_list_make_empty(&shader->system_values);
 220
 221    return progress;
 222 }