1 /*
2 * Copyright © 2019 Collabora, Ltd.
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 (Collabora):
24 * Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
25 */
26
27 #include "nir.h"
28 #include "nir_builder.h"
29
30 /*
31 * Lowers SSBOs to globals, for hardware that lack native SSBO support. When
32 * lowering, *_ssbo_* instructions will become *_global_* instructions,
33 * augmented with load_ssbo_address.
34 *
35 * DOES NOT PERFORM BOUNDS CHECKING. DO NOT USE IN PRODUCTION ON UNTRUSTED
36 * CONTEXTS INCLUDING WEBGL 2.
37 */
38
39 static nir_intrinsic_op
lower_ssbo_op(nir_intrinsic_op op)40 lower_ssbo_op(nir_intrinsic_op op)
41 {
42 switch (op) {
43 case nir_intrinsic_load_ssbo:
44 return nir_intrinsic_load_global;
45
46 case nir_intrinsic_store_ssbo:
47 return nir_intrinsic_store_global;
48
49 case nir_intrinsic_ssbo_atomic_add:
50 return nir_intrinsic_global_atomic_add;
51 case nir_intrinsic_ssbo_atomic_imin:
52 return nir_intrinsic_global_atomic_imin;
53 case nir_intrinsic_ssbo_atomic_umin:
54 return nir_intrinsic_global_atomic_umin;
55 case nir_intrinsic_ssbo_atomic_imax:
56 return nir_intrinsic_global_atomic_imax;
57 case nir_intrinsic_ssbo_atomic_umax:
58 return nir_intrinsic_global_atomic_umax;
59 case nir_intrinsic_ssbo_atomic_and:
60 return nir_intrinsic_global_atomic_and;
61 case nir_intrinsic_ssbo_atomic_or:
62 return nir_intrinsic_global_atomic_or;
63 case nir_intrinsic_ssbo_atomic_xor:
64 return nir_intrinsic_global_atomic_xor;
65 case nir_intrinsic_ssbo_atomic_exchange:
66 return nir_intrinsic_global_atomic_exchange;
67 case nir_intrinsic_ssbo_atomic_comp_swap:
68 return nir_intrinsic_global_atomic_comp_swap;
69
70 case nir_intrinsic_ssbo_atomic_fadd:
71 return nir_intrinsic_global_atomic_fadd;
72 case nir_intrinsic_ssbo_atomic_fmin:
73 return nir_intrinsic_global_atomic_fmin;
74 case nir_intrinsic_ssbo_atomic_fmax:
75 return nir_intrinsic_global_atomic_fmax;
76 case nir_intrinsic_ssbo_atomic_fcomp_swap:
77 return nir_intrinsic_global_atomic_fcomp_swap;
78
79 default:
80 unreachable("Invalid SSBO op");
81 }
82 }
83
84 /* Like SSBO property sysvals, though SSBO index may be indirect. C.f.
85 * nir_load_system_value */
86
87 static inline nir_ssa_def *
nir_load_ssbo_prop(nir_builder * b,nir_intrinsic_op op,nir_src * idx,unsigned bitsize)88 nir_load_ssbo_prop(nir_builder *b, nir_intrinsic_op op,
89 nir_src *idx, unsigned bitsize)
90 {
91 nir_intrinsic_instr *load = nir_intrinsic_instr_create(b->shader, op);
92 load->num_components = 1;
93 nir_src_copy(&load->src[0], idx);
94 nir_ssa_dest_init(&load->instr, &load->dest, 1, bitsize, NULL);
95 nir_builder_instr_insert(b, &load->instr);
96 return &load->dest.ssa;
97 }
98
99 #define nir_ssbo_prop(b, prop, index, bitsize) \
100 nir_load_ssbo_prop(b, nir_intrinsic_##prop, index, bitsize)
101
102 static nir_ssa_def *
lower_ssbo_instr(nir_builder * b,nir_intrinsic_instr * intr)103 lower_ssbo_instr(nir_builder *b, nir_intrinsic_instr *intr)
104 {
105 nir_intrinsic_op op = lower_ssbo_op(intr->intrinsic);
106 bool is_store = op == nir_intrinsic_store_global;
107 bool is_atomic = !is_store && op != nir_intrinsic_load_global;
108
109 /* We have to calculate the address:
110 *
111 * &(SSBO[offset]) = &SSBO + offset
112 */
113
114 nir_src index = intr->src[is_store ? 1 : 0];
115 nir_src *offset_src = nir_get_io_offset_src(intr);
116 nir_ssa_def *offset = nir_ssa_for_src(b, *offset_src, 1);
117
118 nir_ssa_def *address =
119 nir_iadd(b,
120 nir_ssbo_prop(b, load_ssbo_address, &index, 64),
121 nir_u2u64(b, offset));
122
123 /* Create the replacement intrinsic */
124
125 nir_intrinsic_instr *global =
126 nir_intrinsic_instr_create(b->shader, op);
127
128 global->num_components = intr->num_components;
129 global->src[is_store ? 1 : 0] = nir_src_for_ssa(address);
130
131 if (!is_atomic) {
132 nir_intrinsic_set_align_mul(global, nir_intrinsic_align_mul(intr));
133 nir_intrinsic_set_align_offset(global, nir_intrinsic_align_offset(intr));
134 }
135
136 if (is_store) {
137 nir_src_copy(&global->src[0], &intr->src[0]);
138 nir_intrinsic_set_write_mask(global, nir_intrinsic_write_mask(intr));
139 } else {
140 nir_ssa_dest_init(&global->instr, &global->dest,
141 intr->dest.ssa.num_components,
142 intr->dest.ssa.bit_size, NULL);
143
144 if (is_atomic) {
145 nir_src_copy(&global->src[1], &intr->src[2]);
146 if (nir_intrinsic_infos[op].num_srcs > 2)
147 nir_src_copy(&global->src[2], &intr->src[3]);
148 }
149 }
150
151 nir_builder_instr_insert(b, &global->instr);
152 return is_store ? NULL : &global->dest.ssa;
153 }
154
155 static bool
should_lower_ssbo_instr(const nir_instr * instr)156 should_lower_ssbo_instr(const nir_instr *instr)
157 {
158 if (instr->type != nir_instr_type_intrinsic)
159 return false;
160
161 const nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
162
163 switch (intr->intrinsic) {
164 case nir_intrinsic_load_ssbo:
165 case nir_intrinsic_store_ssbo:
166 case nir_intrinsic_ssbo_atomic_add:
167 case nir_intrinsic_ssbo_atomic_imin:
168 case nir_intrinsic_ssbo_atomic_umin:
169 case nir_intrinsic_ssbo_atomic_imax:
170 case nir_intrinsic_ssbo_atomic_umax:
171 case nir_intrinsic_ssbo_atomic_and:
172 case nir_intrinsic_ssbo_atomic_or:
173 case nir_intrinsic_ssbo_atomic_xor:
174 case nir_intrinsic_ssbo_atomic_exchange:
175 case nir_intrinsic_ssbo_atomic_comp_swap:
176 case nir_intrinsic_ssbo_atomic_fadd:
177 case nir_intrinsic_ssbo_atomic_fmin:
178 case nir_intrinsic_ssbo_atomic_fmax:
179 case nir_intrinsic_ssbo_atomic_fcomp_swap:
180 return true;
181 default:
182 return false;
183 }
184
185 return false;
186 }
187
188 bool
nir_lower_ssbo(nir_shader * shader)189 nir_lower_ssbo(nir_shader *shader)
190 {
191 bool progress = false;
192
193 nir_foreach_function(function, shader) {
194 nir_function_impl *impl = function->impl;
195 nir_builder b;
196 nir_builder_init(&b, impl);
197
198 nir_foreach_block(block, impl) {
199 nir_foreach_instr_safe(instr, block) {
200 if (!should_lower_ssbo_instr(instr)) continue;
201 progress = true;
202 b.cursor = nir_before_instr(instr);
203
204 nir_intrinsic_instr *intr = nir_instr_as_intrinsic(instr);
205 nir_ssa_def *replace = lower_ssbo_instr(&b, intr);
206
207 if (replace) {
208 nir_ssa_def_rewrite_uses(&intr->dest.ssa,
209 replace);
210 }
211
212 nir_instr_remove(instr);
213 }
214 }
215 }
216
217 return progress;
218 }
219