1 /*
2 * Copyright © 2015 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
26 /**
27 * \file nir_sweep.c
28 *
29 * The nir_sweep() pass performs a mark and sweep pass over a nir_shader's associated
30 * memory - anything still connected to the program will be kept, and any dead memory
31 * we dropped on the floor will be freed.
32 *
33 * The expectation is that drivers should call this when finished compiling the shader
34 * (after any optimization, lowering, and so on). However, it's also fine to call it
35 * earlier, and even many times, trading CPU cycles for memory savings.
36 */
37
38 #define steal_list(mem_ctx, type, list) \
39 foreach_list_typed(type, obj, node, list) { \
40 ralloc_steal(mem_ctx, obj); \
41 }
42
43 static void sweep_cf_node(nir_shader *nir, nir_cf_node *cf_node);
44
45 static void
sweep_block(nir_shader * nir,nir_block * block)46 sweep_block(nir_shader *nir, nir_block *block)
47 {
48 ralloc_steal(nir, block);
49
50 /* sweep_impl will mark all metadata invalid. We can safely release all of
51 * this here.
52 */
53 ralloc_free(block->live_in);
54 block->live_in = NULL;
55
56 ralloc_free(block->live_out);
57 block->live_out = NULL;
58
59 nir_foreach_instr(instr, block) {
60 gc_mark_live(nir->gctx, instr);
61
62 switch (instr->type) {
63 case nir_instr_type_tex:
64 gc_mark_live(nir->gctx, nir_instr_as_tex(instr)->src);
65 break;
66 case nir_instr_type_phi:
67 nir_foreach_phi_src(src, nir_instr_as_phi(instr))
68 gc_mark_live(nir->gctx, src);
69 break;
70 default:
71 break;
72 }
73 }
74 }
75
76 static void
sweep_if(nir_shader * nir,nir_if * iff)77 sweep_if(nir_shader *nir, nir_if *iff)
78 {
79 ralloc_steal(nir, iff);
80
81 foreach_list_typed(nir_cf_node, cf_node, node, &iff->then_list) {
82 sweep_cf_node(nir, cf_node);
83 }
84
85 foreach_list_typed(nir_cf_node, cf_node, node, &iff->else_list) {
86 sweep_cf_node(nir, cf_node);
87 }
88 }
89
90 static void
sweep_loop(nir_shader * nir,nir_loop * loop)91 sweep_loop(nir_shader *nir, nir_loop *loop)
92 {
93 assert(!nir_loop_has_continue_construct(loop));
94 ralloc_steal(nir, loop);
95
96 foreach_list_typed(nir_cf_node, cf_node, node, &loop->body) {
97 sweep_cf_node(nir, cf_node);
98 }
99 }
100
101 static void
sweep_cf_node(nir_shader * nir,nir_cf_node * cf_node)102 sweep_cf_node(nir_shader *nir, nir_cf_node *cf_node)
103 {
104 switch (cf_node->type) {
105 case nir_cf_node_block:
106 sweep_block(nir, nir_cf_node_as_block(cf_node));
107 break;
108 case nir_cf_node_if:
109 sweep_if(nir, nir_cf_node_as_if(cf_node));
110 break;
111 case nir_cf_node_loop:
112 sweep_loop(nir, nir_cf_node_as_loop(cf_node));
113 break;
114 default:
115 unreachable("Invalid CF node type");
116 }
117 }
118
119 static void
sweep_impl(nir_shader * nir,nir_function_impl * impl)120 sweep_impl(nir_shader *nir, nir_function_impl *impl)
121 {
122 ralloc_steal(nir, impl);
123
124 steal_list(nir, nir_variable, &impl->locals);
125
126 foreach_list_typed(nir_cf_node, cf_node, node, &impl->body) {
127 sweep_cf_node(nir, cf_node);
128 }
129
130 sweep_block(nir, impl->end_block);
131
132 /* Wipe out all the metadata, if any. */
133 nir_metadata_preserve(impl, nir_metadata_none);
134 }
135
136 static void
sweep_function(nir_shader * nir,nir_function * f)137 sweep_function(nir_shader *nir, nir_function *f)
138 {
139 ralloc_steal(nir, f);
140 ralloc_steal(nir, f->params);
141
142 if (f->impl)
143 sweep_impl(nir, f->impl);
144 }
145
146 void
nir_sweep(nir_shader * nir)147 nir_sweep(nir_shader *nir)
148 {
149 void *rubbish = ralloc_context(NULL);
150
151 struct list_head instr_gc_list;
152 list_inithead(&instr_gc_list);
153
154 /* First, move ownership of all the memory to a temporary context; assume dead. */
155 ralloc_adopt(rubbish, nir);
156
157 /* Start sweeping */
158 gc_sweep_start(nir->gctx);
159
160 ralloc_steal(nir, nir->gctx);
161 ralloc_steal(nir, (char *)nir->info.name);
162 if (nir->info.label)
163 ralloc_steal(nir, (char *)nir->info.label);
164
165 /* Variables are not dead. Steal them back. */
166 steal_list(nir, nir_variable, &nir->variables);
167
168 /* Recurse into functions, stealing their contents back. */
169 foreach_list_typed(nir_function, func, node, &nir->functions) {
170 sweep_function(nir, func);
171 }
172
173 ralloc_steal(nir, nir->constant_data);
174 ralloc_steal(nir, nir->xfb_info);
175 ralloc_steal(nir, nir->printf_info);
176 for (int i = 0; i < nir->printf_info_count; i++) {
177 ralloc_steal(nir, nir->printf_info[i].arg_sizes);
178 ralloc_steal(nir, nir->printf_info[i].strings);
179 }
180
181 /* Free everything we didn't steal back. */
182 gc_sweep_end(nir->gctx);
183 ralloc_free(rubbish);
184 }
185