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 = nir_load_work_group_id(b);
  66          nir_ssa_def *local_id = nir_load_local_invocation_id(b);
  67
  68          sysval = nir_iadd(b, nir_imul(b, group_id,
  69                                        nir_build_imm(b, 3, 32, local_size)),
  70                               local_id);
  71          break;
  72       }
  73
  74       case SYSTEM_VALUE_LOCAL_INVOCATION_INDEX: {
  75          /* If lower_cs_local_index_from_id is true, then we derive the local
  76           * index from the local id.
  77           */
  78          if (!b->shader->options->lower_cs_local_index_from_id)
  79             break;
  80
  81          /* From the GLSL man page for gl_LocalInvocationIndex:
  82           *
  83           *    "The value of gl_LocalInvocationIndex is equal to
  84           *    gl_LocalInvocationID.z * gl_WorkGroupSize.x *
  85           *    gl_WorkGroupSize.y + gl_LocalInvocationID.y *
  86           *    gl_WorkGroupSize.x + gl_LocalInvocationID.x"
  87           */
  88          nir_ssa_def *local_id = nir_load_local_invocation_id(b);
  89
  90          nir_ssa_def *size_x = nir_imm_int(b, b->shader->info.cs.local_size[0]);
  91          nir_ssa_def *size_y = nir_imm_int(b, b->shader->info.cs.local_size[1]);
  92
  93          sysval = nir_imul(b, nir_channel(b, local_id, 2),
  94                               nir_imul(b, size_x, size_y));
  95          sysval = nir_iadd(b, sysval,
  96                               nir_imul(b, nir_channel(b, local_id, 1), size_x));
  97          sysval = nir_iadd(b, sysval, nir_channel(b, local_id, 0));
  98          break;
  99       }
 100
 101       case SYSTEM_VALUE_VERTEX_ID:
 102          if (b->shader->options->vertex_id_zero_based) {
 103             sysval = nir_iadd(b,
 104                               nir_load_vertex_id_zero_base(b),
 105                               nir_load_base_vertex(b));
 106          } else {
 107             sysval = nir_load_vertex_id(b);
 108          }
 109          break;
 110
 111       case SYSTEM_VALUE_INSTANCE_INDEX:
 112          sysval = nir_iadd(b,
 113                            nir_load_instance_id(b),
 114                            nir_load_base_instance(b));
 115          break;
 116
 117       default:
 118          break;
 119       }
 120
 121       if (sysval == NULL) {
 122          nir_intrinsic_op sysval_op =
 123             nir_intrinsic_from_system_value(var->data.location);
 124          sysval = nir_load_system_value(b, sysval_op, 0);
 125       }
 126
 127       nir_ssa_def_rewrite_uses(&load_var->dest.ssa, nir_src_for_ssa(sysval));
 128       nir_instr_remove(&load_var->instr);
 129
 130       progress = true;
 131    }
 132
 133    return progress;
 134 }
 135
 136 static bool
 137 convert_impl(nir_function_impl *impl)
 138 {
 139    bool progress = false;
 140    nir_builder builder;
 141    nir_builder_init(&builder, impl);
 142
 143    nir_foreach_block(block, impl) {
 144       progress |= convert_block(block, &builder);
 145    }
 146
 147    nir_metadata_preserve(impl, nir_metadata_block_index |
 148                                nir_metadata_dominance);
 149    return progress;
 150 }
 151
 152 bool
 153 nir_lower_system_values(nir_shader *shader)
 154 {
 155    bool progress = false;
 156
 157    nir_foreach_function(function, shader) {
 158       if (function->impl)
 159          progress = convert_impl(function->impl) || progress;
 160    }
 161
 162    exec_list_make_empty(&shader->system_values);
 163
 164    return progress;
 165 }