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 #include "nir_deref.h"
27
28 static void
29 emit_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
30 nir_deref_instr *parent,
31 nir_deref_instr **deref_arr,
32 nir_def **dest, nir_def *src);
33
34 static void
emit_indirect_load_store_deref(nir_builder * b,nir_intrinsic_instr * orig_instr,nir_deref_instr * parent,nir_deref_instr ** deref_arr,int start,int end,nir_def ** dest,nir_def * src)35 emit_indirect_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
36 nir_deref_instr *parent,
37 nir_deref_instr **deref_arr,
38 int start, int end,
39 nir_def **dest, nir_def *src)
40 {
41 assert(start < end);
42 if (start == end - 1) {
43 emit_load_store_deref(b, orig_instr,
44 nir_build_deref_array_imm(b, parent, start),
45 deref_arr + 1, dest, src);
46 } else {
47 int mid = start + (end - start) / 2;
48
49 nir_def *then_dest, *else_dest;
50
51 nir_deref_instr *deref = *deref_arr;
52 assert(deref->deref_type == nir_deref_type_array);
53
54 nir_push_if(b, nir_ilt_imm(b, deref->arr.index.ssa, mid));
55 emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
56 start, mid, &then_dest, src);
57 nir_push_else(b, NULL);
58 emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
59 mid, end, &else_dest, src);
60 nir_pop_if(b, NULL);
61
62 if (src == NULL)
63 *dest = nir_if_phi(b, then_dest, else_dest);
64 }
65 }
66
67 static void
emit_load_store_deref(nir_builder * b,nir_intrinsic_instr * orig_instr,nir_deref_instr * parent,nir_deref_instr ** deref_arr,nir_def ** dest,nir_def * src)68 emit_load_store_deref(nir_builder *b, nir_intrinsic_instr *orig_instr,
69 nir_deref_instr *parent,
70 nir_deref_instr **deref_arr,
71 nir_def **dest, nir_def *src)
72 {
73 for (; *deref_arr; deref_arr++) {
74 nir_deref_instr *deref = *deref_arr;
75 if (deref->deref_type == nir_deref_type_array &&
76 !nir_src_is_const(deref->arr.index)) {
77 int length = glsl_get_length(parent->type);
78
79 emit_indirect_load_store_deref(b, orig_instr, parent, deref_arr,
80 0, length, dest, src);
81 return;
82 }
83
84 parent = nir_build_deref_follower(b, parent, deref);
85 }
86
87 /* We reached the end of the deref chain. Emit the instruction */
88 assert(*deref_arr == NULL);
89
90 if (src == NULL) {
91 /* This is a load instruction */
92 nir_intrinsic_instr *load =
93 nir_intrinsic_instr_create(b->shader, orig_instr->intrinsic);
94 load->num_components = orig_instr->num_components;
95
96 load->src[0] = nir_src_for_ssa(&parent->def);
97
98 /* Copy over any other sources. This is needed for interp_deref_at */
99 for (unsigned i = 1;
100 i < nir_intrinsic_infos[orig_instr->intrinsic].num_srcs; i++)
101 load->src[i] = nir_src_for_ssa(orig_instr->src[i].ssa);
102
103 nir_def_init(&load->instr, &load->def,
104 orig_instr->def.num_components,
105 orig_instr->def.bit_size);
106 nir_builder_instr_insert(b, &load->instr);
107 *dest = &load->def;
108 } else {
109 assert(orig_instr->intrinsic == nir_intrinsic_store_deref);
110 nir_store_deref(b, parent, src, nir_intrinsic_write_mask(orig_instr));
111 }
112 }
113
114 static bool
lower_indirect_derefs_block(nir_block * block,nir_builder * b,nir_variable_mode modes,const struct set * vars,uint32_t max_lower_array_len)115 lower_indirect_derefs_block(nir_block *block, nir_builder *b,
116 nir_variable_mode modes,
117 const struct set *vars,
118 uint32_t max_lower_array_len)
119 {
120 bool progress = false;
121
122 nir_foreach_instr_safe(instr, block) {
123 if (instr->type != nir_instr_type_intrinsic)
124 continue;
125
126 nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
127 if (intrin->intrinsic != nir_intrinsic_load_deref &&
128 intrin->intrinsic != nir_intrinsic_interp_deref_at_centroid &&
129 intrin->intrinsic != nir_intrinsic_interp_deref_at_sample &&
130 intrin->intrinsic != nir_intrinsic_interp_deref_at_offset &&
131 intrin->intrinsic != nir_intrinsic_interp_deref_at_vertex &&
132 intrin->intrinsic != nir_intrinsic_store_deref)
133 continue;
134
135 nir_deref_instr *deref = nir_src_as_deref(intrin->src[0]);
136
137 /* Walk the deref chain back to the base and look for indirects */
138 uint32_t indirect_array_len = 1;
139 bool has_indirect = false;
140 nir_deref_instr *base = deref;
141 while (base && base->deref_type != nir_deref_type_var) {
142 nir_deref_instr *parent = nir_deref_instr_parent(base);
143 if (base->deref_type == nir_deref_type_array &&
144 !nir_src_is_const(base->arr.index)) {
145 indirect_array_len *= glsl_get_length(parent->type);
146 has_indirect = true;
147 }
148
149 base = parent;
150 }
151
152 if (!has_indirect || !base || indirect_array_len > max_lower_array_len)
153 continue;
154
155 if (glsl_type_is_cmat(base->type))
156 continue;
157
158 /* Only lower variables whose mode is in the mask, or compact
159 * array variables. (We can't handle indirects on tightly packed
160 * scalar arrays, so we need to lower them regardless.)
161 */
162 if (!(modes & base->var->data.mode) && !base->var->data.compact)
163 continue;
164
165 if (vars && !_mesa_set_search(vars, base->var))
166 continue;
167
168 b->cursor = nir_instr_remove(&intrin->instr);
169
170 nir_deref_path path;
171 nir_deref_path_init(&path, deref, NULL);
172 assert(path.path[0] == base);
173
174 if (intrin->intrinsic == nir_intrinsic_store_deref) {
175 emit_load_store_deref(b, intrin, base, &path.path[1],
176 NULL, intrin->src[1].ssa);
177 } else {
178 nir_def *result;
179 emit_load_store_deref(b, intrin, base, &path.path[1],
180 &result, NULL);
181 nir_def_rewrite_uses(&intrin->def, result);
182 }
183
184 nir_deref_path_finish(&path);
185
186 progress = true;
187 }
188
189 return progress;
190 }
191
192 static bool
lower_indirects_impl(nir_function_impl * impl,nir_variable_mode modes,const struct set * vars,uint32_t max_lower_array_len)193 lower_indirects_impl(nir_function_impl *impl, nir_variable_mode modes,
194 const struct set *vars, uint32_t max_lower_array_len)
195 {
196 nir_builder builder = nir_builder_create(impl);
197 bool progress = false;
198
199 nir_foreach_block_safe(block, impl) {
200 progress |= lower_indirect_derefs_block(block, &builder, modes, vars,
201 max_lower_array_len);
202 }
203
204 if (progress)
205 nir_metadata_preserve(impl, nir_metadata_none);
206 else
207 nir_metadata_preserve(impl, nir_metadata_all);
208
209 return progress;
210 }
211
212 /** Lowers indirect variable loads/stores to direct loads/stores.
213 *
214 * The pass works by replacing any indirect load or store with an if-ladder
215 * that does a binary search on the array index.
216 */
217 bool
nir_lower_indirect_derefs(nir_shader * shader,nir_variable_mode modes,uint32_t max_lower_array_len)218 nir_lower_indirect_derefs(nir_shader *shader, nir_variable_mode modes,
219 uint32_t max_lower_array_len)
220 {
221 bool progress = false;
222
223 nir_foreach_function_impl(impl, shader) {
224 progress = lower_indirects_impl(impl, modes, NULL, max_lower_array_len) ||
225 progress;
226 }
227
228 return progress;
229 }
230
231 /** Lowers indirects on any variables in the given set */
232 bool
nir_lower_indirect_var_derefs(nir_shader * shader,const struct set * vars)233 nir_lower_indirect_var_derefs(nir_shader *shader, const struct set *vars)
234 {
235 bool progress = false;
236
237 nir_foreach_function_impl(impl, shader) {
238 progress = lower_indirects_impl(impl, nir_var_uniform, vars, UINT_MAX) ||
239 progress;
240 }
241
242 return progress;
243 }
244