src/compiler/nir/nir_lower_variable_initializers.c

   1 /*
   2  * Copyright © 2016 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
  24 #include "nir.h"
  25 #include "nir_builder.h"
  26
  27 static void
  28 build_constant_load(nir_builder *b, nir_deref_instr *deref, nir_constant *c)
  29 {
  30    if (glsl_type_is_vector_or_scalar(deref->type)) {
  31       nir_load_const_instr *load =
  32          nir_load_const_instr_create(b->shader,
  33                                      glsl_get_vector_elements(deref->type),
  34                                      glsl_get_bit_size(deref->type));
  35       memcpy(load->value, c->values, sizeof(*load->value) * load->def.num_components);
  36       nir_builder_instr_insert(b, &load->instr);
  37       nir_store_deref(b, deref, &load->def, ~0);
  38    } else if (glsl_type_is_struct_or_ifc(deref->type)) {
  39       unsigned len = glsl_get_length(deref->type);
  40       for (unsigned i = 0; i < len; i++) {
  41          build_constant_load(b, nir_build_deref_struct(b, deref, i),
  42                              c->elements[i]);
  43       }
  44    } else {
  45       assert(glsl_type_is_array(deref->type) ||
  46              glsl_type_is_matrix(deref->type));
  47       unsigned len = glsl_get_length(deref->type);
  48       for (unsigned i = 0; i < len; i++) {
  49          build_constant_load(b,
  50                              nir_build_deref_array_imm(b, deref, i),
  51                              c->elements[i]);
  52       }
  53    }
  54 }
  55
  56 static bool
  57 lower_const_initializer(struct nir_builder *b, struct exec_list *var_list)
  58 {
  59    bool progress = false;
  60
  61    b->cursor = nir_before_cf_list(&b->impl->body);
  62
  63    nir_foreach_variable(var, var_list) {
  64       if (var->constant_initializer) {
  65          build_constant_load(b, nir_build_deref_var(b, var),
  66                              var->constant_initializer);
  67
  68          progress = true;
  69          var->constant_initializer = NULL;
  70       } else if (var->pointer_initializer) {
  71          nir_deref_instr *src_deref = nir_build_deref_var(b, var->pointer_initializer);
  72          nir_deref_instr *dst_deref = nir_build_deref_var(b, var);
  73
  74          /* Note that this stores a pointer to src into dst */
  75          nir_store_deref(b, dst_deref, &src_deref->dest.ssa, ~0);
  76
  77          progress = true;
  78          var->pointer_initializer = NULL;
  79       }
  80
  81    }
  82
  83    return progress;
  84 }
  85
  86 bool
  87 nir_lower_variable_initializers(nir_shader *shader, nir_variable_mode modes)
  88 {
  89    bool progress = false;
  90
  91    nir_foreach_function(function, shader) {
  92       if (!function->impl)
  93          continue;
  94
  95       bool impl_progress = false;
  96
  97       nir_builder builder;
  98       nir_builder_init(&builder, function->impl);
  99
 100       if ((modes & nir_var_shader_out) && function->is_entrypoint)
 101          impl_progress |= lower_const_initializer(&builder, &shader->outputs);
 102
 103       if ((modes & nir_var_shader_temp) && function->is_entrypoint)
 104          impl_progress |= lower_const_initializer(&builder, &shader->globals);
 105
 106       if ((modes & nir_var_system_value) && function->is_entrypoint)
 107          impl_progress |= lower_const_initializer(&builder, &shader->system_values);
 108
 109       if (modes & nir_var_function_temp)
 110          impl_progress |= lower_const_initializer(&builder, &function->impl->locals);
 111
 112       if (impl_progress) {
 113          progress = true;
 114          nir_metadata_preserve(function->impl, nir_metadata_block_index |
 115                                                nir_metadata_dominance |
 116                                                nir_metadata_live_ssa_defs);
 117       } else {
 118          nir_metadata_preserve(function->impl, nir_metadata_all);
 119       }
 120    }
 121
 122    return progress;
 123 }