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
31static bool
32convert_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 =
91            nir_imm_int(b, b->shader->info->cs.local_size[0]);
92         nir_ssa_def *size_y =
93            nir_imm_int(b, b->shader->info->cs.local_size[1]);
94
95         sysval = nir_imul(b, nir_channel(b, local_id, 2),
96                              nir_imul(b, size_x, size_y));
97         sysval = nir_iadd(b, sysval,
98                              nir_imul(b, nir_channel(b, local_id, 1), size_x));
99         sysval = nir_iadd(b, sysval, nir_channel(b, local_id, 0));
100         break;
101      }
102
103      case SYSTEM_VALUE_VERTEX_ID:
104         if (b->shader->options->vertex_id_zero_based) {
105            sysval = nir_iadd(b,
106                              nir_load_vertex_id_zero_base(b),
107                              nir_load_base_vertex(b));
108         } else {
109            sysval = nir_load_vertex_id(b);
110         }
111         break;
112
113      case SYSTEM_VALUE_INSTANCE_INDEX:
114         sysval = nir_iadd(b,
115                           nir_load_instance_id(b),
116                           nir_load_base_instance(b));
117         break;
118
119      default:
120         break;
121      }
122
123      if (sysval == NULL) {
124         nir_intrinsic_op sysval_op =
125            nir_intrinsic_from_system_value(var->data.location);
126         sysval = nir_load_system_value(b, sysval_op, 0);
127      }
128
129      nir_ssa_def_rewrite_uses(&load_var->dest.ssa, nir_src_for_ssa(sysval));
130      nir_instr_remove(&load_var->instr);
131
132      progress = true;
133   }
134
135   return progress;
136}
137
138static bool
139convert_impl(nir_function_impl *impl)
140{
141   bool progress = false;
142   nir_builder builder;
143   nir_builder_init(&builder, impl);
144
145   nir_foreach_block(block, impl) {
146      progress |= convert_block(block, &builder);
147   }
148
149   nir_metadata_preserve(impl, nir_metadata_block_index |
150                               nir_metadata_dominance);
151   return progress;
152}
153
154bool
155nir_lower_system_values(nir_shader *shader)
156{
157   bool progress = false;
158
159   nir_foreach_function(function, shader) {
160      if (function->impl)
161         progress = convert_impl(function->impl) || progress;
162   }
163
164   exec_list_make_empty(&shader->system_values);
165
166   return progress;
167}
168