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 30static void 31add_var_use_intrinsic(nir_intrinsic_instr *instr, struct set *live) 32{ 33 unsigned num_vars = nir_intrinsic_infos[instr->intrinsic].num_variables; 34 35 switch (instr->intrinsic) { 36 case nir_intrinsic_copy_var: 37 _mesa_set_add(live, instr->variables[1]->var); 38 /* Fall through */ 39 case nir_intrinsic_store_var: { 40 /* The first source in both copy_var and store_var is the destination. 41 * If the variable is a local that never escapes the shader, then we 42 * don't mark it as live for just a store. 43 */ 44 nir_variable_mode mode = instr->variables[0]->var->data.mode; 45 if (!(mode & (nir_var_local | nir_var_global | nir_var_shared))) 46 _mesa_set_add(live, instr->variables[0]->var); 47 break; 48 } 49 50 default: 51 for (unsigned i = 0; i < num_vars; i++) { 52 _mesa_set_add(live, instr->variables[i]->var); 53 } 54 break; 55 } 56} 57 58static void 59add_var_use_call(nir_call_instr *instr, struct set *live) 60{ 61 if (instr->return_deref != NULL) { 62 nir_variable *var = instr->return_deref->var; 63 _mesa_set_add(live, var); 64 } 65 66 for (unsigned i = 0; i < instr->num_params; i++) { 67 nir_variable *var = instr->params[i]->var; 68 _mesa_set_add(live, var); 69 } 70} 71 72static void 73add_var_use_tex(nir_tex_instr *instr, struct set *live) 74{ 75 if (instr->texture != NULL) { 76 nir_variable *var = instr->texture->var; 77 _mesa_set_add(live, var); 78 } 79 80 if (instr->sampler != NULL) { 81 nir_variable *var = instr->sampler->var; 82 _mesa_set_add(live, var); 83 } 84} 85 86static void 87add_var_use_shader(nir_shader *shader, struct set *live) 88{ 89 nir_foreach_function(function, shader) { 90 if (function->impl) { 91 nir_foreach_block(block, function->impl) { 92 nir_foreach_instr(instr, block) { 93 switch(instr->type) { 94 case nir_instr_type_intrinsic: 95 add_var_use_intrinsic(nir_instr_as_intrinsic(instr), live); 96 break; 97 98 case nir_instr_type_call: 99 add_var_use_call(nir_instr_as_call(instr), live); 100 break; 101 102 case nir_instr_type_tex: 103 add_var_use_tex(nir_instr_as_tex(instr), live); 104 break; 105 106 default: 107 break; 108 } 109 } 110 } 111 } 112 } 113} 114 115static void 116remove_dead_var_writes(nir_shader *shader, struct set *live) 117{ 118 nir_foreach_function(function, shader) { 119 if (!function->impl) 120 continue; 121 122 nir_foreach_block(block, function->impl) { 123 nir_foreach_instr_safe(instr, block) { 124 if (instr->type != nir_instr_type_intrinsic) 125 continue; 126 127 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); 128 if (intrin->intrinsic != nir_intrinsic_copy_var && 129 intrin->intrinsic != nir_intrinsic_store_var) 130 continue; 131 132 /* Stores to dead variables need to be removed */ 133 if (intrin->variables[0]->var->data.mode == 0) 134 nir_instr_remove(instr); 135 } 136 } 137 } 138} 139 140static bool 141remove_dead_vars(struct exec_list *var_list, struct set *live) 142{ 143 bool progress = false; 144 145 foreach_list_typed_safe(nir_variable, var, node, var_list) { 146 struct set_entry *entry = _mesa_set_search(live, var); 147 if (entry == NULL) { 148 /* Mark this variable as used by setting the mode to 0 */ 149 var->data.mode = 0; 150 exec_node_remove(&var->node); 151 progress = true; 152 } 153 } 154 155 return progress; 156} 157 158bool 159nir_remove_dead_variables(nir_shader *shader, nir_variable_mode modes) 160{ 161 bool progress = false; 162 struct set *live = 163 _mesa_set_create(NULL, _mesa_hash_pointer, _mesa_key_pointer_equal); 164 165 add_var_use_shader(shader, live); 166 167 if (modes & nir_var_uniform) 168 progress = remove_dead_vars(&shader->uniforms, live) || progress; 169 170 if (modes & nir_var_shader_in) 171 progress = remove_dead_vars(&shader->inputs, live) || progress; 172 173 if (modes & nir_var_shader_out) 174 progress = remove_dead_vars(&shader->outputs, live) || progress; 175 176 if (modes & nir_var_global) 177 progress = remove_dead_vars(&shader->globals, live) || progress; 178 179 if (modes & nir_var_system_value) 180 progress = remove_dead_vars(&shader->system_values, live) || progress; 181 182 if (modes & nir_var_shared) 183 progress = remove_dead_vars(&shader->shared, live) || progress; 184 185 if (modes & nir_var_local) { 186 nir_foreach_function(function, shader) { 187 if (function->impl) { 188 if (remove_dead_vars(&function->impl->locals, live)) 189 progress = true; 190 } 191 } 192 } 193 194 if (progress) { 195 remove_dead_var_writes(shader, live); 196 197 nir_foreach_function(function, shader) { 198 if (function->impl) { 199 nir_metadata_preserve(function->impl, nir_metadata_block_index | 200 nir_metadata_dominance); 201 } 202 } 203 } 204 205 _mesa_set_destroy(live, NULL); 206 return progress; 207} 208