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
build_constant_load(nir_builder * b,nir_deref_instr * deref,nir_constant * c)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
lower_const_initializer(struct nir_builder * b,struct exec_list * var_list,nir_variable_mode modes)57 lower_const_initializer(struct nir_builder *b, struct exec_list *var_list,
58 nir_variable_mode modes)
59 {
60 bool progress = false;
61
62 b->cursor = nir_before_cf_list(&b->impl->body);
63
64 nir_foreach_variable_in_list(var, var_list) {
65 if (!(var->data.mode & modes))
66 continue;
67
68 if (var->constant_initializer) {
69 build_constant_load(b, nir_build_deref_var(b, var),
70 var->constant_initializer);
71
72 progress = true;
73 var->constant_initializer = NULL;
74 } else if (var->pointer_initializer) {
75 nir_deref_instr *src_deref = nir_build_deref_var(b, var->pointer_initializer);
76 nir_deref_instr *dst_deref = nir_build_deref_var(b, var);
77
78 /* Note that this stores a pointer to src into dst */
79 nir_store_deref(b, dst_deref, &src_deref->dest.ssa, ~0);
80
81 progress = true;
82 var->pointer_initializer = NULL;
83 }
84
85 }
86
87 return progress;
88 }
89
90 bool
nir_lower_variable_initializers(nir_shader * shader,nir_variable_mode modes)91 nir_lower_variable_initializers(nir_shader *shader, nir_variable_mode modes)
92 {
93 bool progress = false;
94
95 /* Only some variables have initializers that we want to lower. Others
96 * such as uniforms have initializers which are useful later during linking
97 * so we want to skip over those. Restrict to only variable types where
98 * initializers make sense so that callers can use nir_var_all.
99 */
100 modes &= nir_var_shader_out |
101 nir_var_shader_temp |
102 nir_var_function_temp |
103 nir_var_system_value;
104
105 nir_foreach_function(function, shader) {
106 if (!function->impl)
107 continue;
108
109 bool impl_progress = false;
110
111 nir_builder builder;
112 nir_builder_init(&builder, function->impl);
113
114 if ((modes & ~nir_var_function_temp) && function->is_entrypoint) {
115 impl_progress |= lower_const_initializer(&builder,
116 &shader->variables,
117 modes);
118 }
119
120 if (modes & nir_var_function_temp) {
121 impl_progress |= lower_const_initializer(&builder,
122 &function->impl->locals,
123 nir_var_function_temp);
124 }
125
126 if (impl_progress) {
127 progress = true;
128 nir_metadata_preserve(function->impl, nir_metadata_block_index |
129 nir_metadata_dominance |
130 nir_metadata_live_ssa_defs);
131 } else {
132 nir_metadata_preserve(function->impl, nir_metadata_all);
133 }
134 }
135
136 return progress;
137 }
138