2 * Copyright © 2014 Intel Corporation
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:
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
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
24 * Connor Abbott (cwabbott0@gmail.com)
31 * Implements the algorithms for computing the dominance tree and the
32 * dominance frontier from "A Simple, Fast Dominance Algorithm" by Cooper,
33 * Harvey, and Kennedy.
37 init_block(nir_block
*block
, nir_function_impl
*impl
)
39 if (block
== nir_start_block(impl
))
40 block
->imm_dom
= block
;
42 block
->imm_dom
= NULL
;
43 block
->num_dom_children
= 0;
45 struct set_entry
*entry
;
46 set_foreach(block
->dom_frontier
, entry
) {
47 _mesa_set_remove(block
->dom_frontier
, entry
);
54 intersect(nir_block
*b1
, nir_block
*b2
)
58 * Note, the comparisons here are the opposite of what the paper says
59 * because we index blocks from beginning -> end (i.e. reverse
60 * post-order) instead of post-order like they assume.
62 while (b1
->index
> b2
->index
)
64 while (b2
->index
> b1
->index
)
72 calc_dominance(nir_block
*block
)
74 nir_block
*new_idom
= NULL
;
75 struct set_entry
*entry
;
76 set_foreach(block
->predecessors
, entry
) {
77 nir_block
*pred
= (nir_block
*) entry
->key
;
81 new_idom
= intersect(pred
, new_idom
);
87 if (block
->imm_dom
!= new_idom
) {
88 block
->imm_dom
= new_idom
;
96 calc_dom_frontier(nir_block
*block
)
98 if (block
->predecessors
->entries
> 1) {
99 struct set_entry
*entry
;
100 set_foreach(block
->predecessors
, entry
) {
101 nir_block
*runner
= (nir_block
*) entry
->key
;
103 /* Skip unreachable predecessors */
104 if (runner
->imm_dom
== NULL
)
107 while (runner
!= block
->imm_dom
) {
108 _mesa_set_add(runner
->dom_frontier
, block
);
109 runner
= runner
->imm_dom
;
118 * Compute each node's children in the dominance tree from the immediate
119 * dominator information. We do this in three stages:
121 * 1. Calculate the number of children each node has
122 * 2. Allocate arrays, setting the number of children to 0 again
123 * 3. For each node, add itself to its parent's list of children, using
124 * num_dom_children as an index - at the end of this step, num_dom_children
125 * for each node will be the same as it was at the end of step #1.
129 calc_dom_children(nir_function_impl
* impl
)
131 void *mem_ctx
= ralloc_parent(impl
);
133 nir_foreach_block(block
, impl
) {
135 block
->imm_dom
->num_dom_children
++;
138 nir_foreach_block(block
, impl
) {
139 block
->dom_children
= ralloc_array(mem_ctx
, nir_block
*,
140 block
->num_dom_children
);
141 block
->num_dom_children
= 0;
144 nir_foreach_block(block
, impl
) {
145 if (block
->imm_dom
) {
146 block
->imm_dom
->dom_children
[block
->imm_dom
->num_dom_children
++]
153 calc_dfs_indicies(nir_block
*block
, unsigned *index
)
155 block
->dom_pre_index
= (*index
)++;
157 for (unsigned i
= 0; i
< block
->num_dom_children
; i
++)
158 calc_dfs_indicies(block
->dom_children
[i
], index
);
160 block
->dom_post_index
= (*index
)++;
164 nir_calc_dominance_impl(nir_function_impl
*impl
)
166 if (impl
->valid_metadata
& nir_metadata_dominance
)
169 nir_metadata_require(impl
, nir_metadata_block_index
);
172 nir_foreach_block(block
, impl
) {
173 init_block(block
, impl
);
176 bool progress
= true;
179 nir_foreach_block(block
, impl
) {
180 if (block
!= nir_start_block(impl
))
181 progress
|= calc_dominance(block
);
185 nir_foreach_block(block
, impl
) {
186 calc_dom_frontier(block
);
189 nir_block
*start_block
= nir_start_block(impl
);
190 start_block
->imm_dom
= NULL
;
192 calc_dom_children(impl
);
194 unsigned dfs_index
= 0;
195 calc_dfs_indicies(start_block
, &dfs_index
);
199 nir_calc_dominance(nir_shader
*shader
)
201 nir_foreach_function(function
, shader
) {
203 nir_calc_dominance_impl(function
->impl
);
208 * Computes the least common anscestor of two blocks. If one of the blocks
209 * is null, the other block is returned.
212 nir_dominance_lca(nir_block
*b1
, nir_block
*b2
)
220 assert(nir_cf_node_get_function(&b1
->cf_node
) ==
221 nir_cf_node_get_function(&b2
->cf_node
));
223 assert(nir_cf_node_get_function(&b1
->cf_node
)->valid_metadata
&
224 nir_metadata_dominance
);
226 return intersect(b1
, b2
);
230 * Returns true if parent dominates child
233 nir_block_dominates(nir_block
*parent
, nir_block
*child
)
235 assert(nir_cf_node_get_function(&parent
->cf_node
) ==
236 nir_cf_node_get_function(&child
->cf_node
));
238 assert(nir_cf_node_get_function(&parent
->cf_node
)->valid_metadata
&
239 nir_metadata_dominance
);
241 return child
->dom_pre_index
>= parent
->dom_pre_index
&&
242 child
->dom_post_index
<= parent
->dom_post_index
;
246 nir_dump_dom_tree_impl(nir_function_impl
*impl
, FILE *fp
)
248 fprintf(fp
, "digraph doms_%s {\n", impl
->function
->name
);
250 nir_foreach_block(block
, impl
) {
252 fprintf(fp
, "\t%u -> %u\n", block
->imm_dom
->index
, block
->index
);
255 fprintf(fp
, "}\n\n");
259 nir_dump_dom_tree(nir_shader
*shader
, FILE *fp
)
261 nir_foreach_function(function
, shader
) {
263 nir_dump_dom_tree_impl(function
->impl
, fp
);
268 nir_dump_dom_frontier_impl(nir_function_impl
*impl
, FILE *fp
)
270 nir_foreach_block(block
, impl
) {
271 fprintf(fp
, "DF(%u) = {", block
->index
);
272 struct set_entry
*entry
;
273 set_foreach(block
->dom_frontier
, entry
) {
274 nir_block
*df
= (nir_block
*) entry
->key
;
275 fprintf(fp
, "%u, ", df
->index
);
282 nir_dump_dom_frontier(nir_shader
*shader
, FILE *fp
)
284 nir_foreach_function(function
, shader
) {
286 nir_dump_dom_frontier_impl(function
->impl
, fp
);
291 nir_dump_cfg_impl(nir_function_impl
*impl
, FILE *fp
)
293 fprintf(fp
, "digraph cfg_%s {\n", impl
->function
->name
);
295 nir_foreach_block(block
, impl
) {
296 if (block
->successors
[0])
297 fprintf(fp
, "\t%u -> %u\n", block
->index
, block
->successors
[0]->index
);
298 if (block
->successors
[1])
299 fprintf(fp
, "\t%u -> %u\n", block
->index
, block
->successors
[1]->index
);
302 fprintf(fp
, "}\n\n");
306 nir_dump_cfg(nir_shader
*shader
, FILE *fp
)
308 nir_foreach_function(function
, shader
) {
310 nir_dump_cfg_impl(function
->impl
, fp
);