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_var = nir_instr_as_intrinsic(instr);
  41
  42       if (load_var->intrinsic != nir_intrinsic_load_var)
  43          continue;
  44
  45       nir_variable *var = load_var->variables[0]->var;
  46       if (var->data.mode != nir_var_system_value)
  47          continue;
  48
  49       b->cursor = nir_after_instr(&load_var->instr);
  50
  51       nir_ssa_def *sysval = NULL;
  52       switch (var->data.location) {
  53       case SYSTEM_VALUE_GLOBAL_INVOCATION_ID: {
  54          /* From the GLSL man page for gl_GlobalInvocationID:
  55           *
  56           *    "The value of gl_GlobalInvocationID is equal to
  57           *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID"
  58           */
  59
  60          nir_const_value local_size;
  61          local_size.u32[0] = b->shader->info.cs.local_size[0];
  62          local_size.u32[1] = b->shader->info.cs.local_size[1];
  63          local_size.u32[2] = b->shader->info.cs.local_size[2];
  64
  65          nir_ssa_def *group_id =
  66             nir_load_system_value(b, nir_intrinsic_load_work_group_id, 0);
  67          nir_ssa_def *local_id =
  68             nir_load_system_value(b, nir_intrinsic_load_local_invocation_id, 0);
  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 =
  91             nir_load_system_value(b, nir_intrinsic_load_local_invocation_id, 0);
  92
  93          nir_ssa_def *size_x = nir_imm_int(b, b->shader->info.cs.local_size[0]);
  94          nir_ssa_def *size_y = nir_imm_int(b, b->shader->info.cs.local_size[1]);
  95
  96          sysval = nir_imul(b, nir_channel(b, local_id, 2),
  97                               nir_imul(b, size_x, size_y));
  98          sysval = nir_iadd(b, sysval,
  99                               nir_imul(b, nir_channel(b, local_id, 1), size_x));
 100          sysval = nir_iadd(b, sysval, nir_channel(b, local_id, 0));
 101          break;
 102       }
 103
 104       case SYSTEM_VALUE_VERTEX_ID:
 105          if (b->shader->options->vertex_id_zero_based) {
 106             sysval = nir_iadd(b,
 107                nir_load_system_value(b, nir_intrinsic_load_vertex_id_zero_base, 0),
 108                nir_load_system_value(b, nir_intrinsic_load_base_vertex, 0));
 109          } else {
 110             sysval = nir_load_system_value(b, nir_intrinsic_load_vertex_id, 0);
 111          }
 112          break;
 113
 114       case SYSTEM_VALUE_INSTANCE_INDEX:
 115          sysval = nir_iadd(b,
 116             nir_load_system_value(b, nir_intrinsic_load_instance_id, 0),
 117             nir_load_system_value(b, nir_intrinsic_load_base_instance, 0));
 118          break;
 119
 120       default:
 121          break;
 122       }
 123
 124       if (sysval == NULL) {
 125          nir_intrinsic_op sysval_op =
 126             nir_intrinsic_from_system_value(var->data.location);
 127          sysval = nir_load_system_value(b, sysval_op, 0);
 128       }
 129
 130       nir_ssa_def_rewrite_uses(&load_var->dest.ssa, nir_src_for_ssa(sysval));
 131       nir_instr_remove(&load_var->instr);
 132
 133       progress = true;
 134    }
 135
 136    return progress;
 137 }
 138
 139 static bool
 140 convert_impl(nir_function_impl *impl)
 141 {
 142    bool progress = false;
 143    nir_builder builder;
 144    nir_builder_init(&builder, impl);
 145
 146    nir_foreach_block(block, impl) {
 147       progress |= convert_block(block, &builder);
 148    }
 149
 150    nir_metadata_preserve(impl, nir_metadata_block_index |
 151                                nir_metadata_dominance);
 152    return progress;
 153 }
 154
 155 bool
 156 nir_lower_system_values(nir_shader *shader)
 157 {
 158    bool progress = false;
 159
 160    nir_foreach_function(function, shader) {
 161       if (function->impl)
 162          progress = convert_impl(function->impl) || progress;
 163    }
 164
 165    exec_list_make_empty(&shader->system_values);
 166
 167    return progress;
 168 }