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1 /*
2  * Copyright © 2012 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  * Authors:
24  *    Eric Anholt <eric@anholt.net>
25  *
26  */
27 
28 #ifndef BRW_CFG_H
29 #define BRW_CFG_H
30 
31 #include "brw_ir.h"
32 #ifdef __cplusplus
33 #include "brw_ir_analysis.h"
34 #endif
35 
36 struct bblock_t;
37 
38 /**
39  * CFG edge types.
40  *
41  * A logical edge represents a potential control flow path of the original
42  * scalar program, while a physical edge represents a control flow path that
43  * may not have existed in the original program but was introduced during
44  * vectorization in order to implement divergent control flow of different
45  * shader invocations within the same SIMD thread.
46  *
47  * All logical edges in the CFG are considered to be physical edges but not
48  * the other way around -- I.e. the logical CFG is a subset of the physical
49  * one.
50  */
51 enum bblock_link_kind {
52    bblock_link_logical = 0,
53    bblock_link_physical
54 };
55 
56 struct bblock_link {
57 #ifdef __cplusplus
58    DECLARE_RALLOC_CXX_OPERATORS(bblock_link)
59 
bblock_linkbblock_link60    bblock_link(bblock_t *block, enum bblock_link_kind kind)
61       : block(block), kind(kind)
62    {
63    }
64 #endif
65 
66    struct exec_node link;
67    struct bblock_t *block;
68 
69    /* Type of this CFG edge.  Because bblock_link_logical also implies
70     * bblock_link_physical, the proper way to test for membership of edge 'l'
71     * in CFG kind 'k' is 'l.kind <= k'.
72     */
73    enum bblock_link_kind kind;
74 };
75 
76 struct backend_shader;
77 struct cfg_t;
78 
79 struct bblock_t {
80 #ifdef __cplusplus
81    DECLARE_RALLOC_CXX_OPERATORS(bblock_t)
82 
83    explicit bblock_t(cfg_t *cfg);
84 
85    void add_successor(void *mem_ctx, bblock_t *successor,
86                       enum bblock_link_kind kind);
87    bool is_predecessor_of(const bblock_t *block,
88                           enum bblock_link_kind kind) const;
89    bool is_successor_of(const bblock_t *block,
90                         enum bblock_link_kind kind) const;
91    bool can_combine_with(const bblock_t *that) const;
92    void combine_with(bblock_t *that);
93    void dump() const;
94 
95    backend_instruction *start();
96    const backend_instruction *start() const;
97    backend_instruction *end();
98    const backend_instruction *end() const;
99 
100    bblock_t *next();
101    const bblock_t *next() const;
102    bblock_t *prev();
103    const bblock_t *prev() const;
104 
105    bool starts_with_control_flow() const;
106    bool ends_with_control_flow() const;
107 
108    backend_instruction *first_non_control_flow_inst();
109    backend_instruction *last_non_control_flow_inst();
110 #endif
111 
112    struct exec_node link;
113    struct cfg_t *cfg;
114 
115    int start_ip;
116    int end_ip;
117 
118    struct exec_list instructions;
119    struct exec_list parents;
120    struct exec_list children;
121    int num;
122 };
123 
124 static inline struct backend_instruction *
bblock_start(struct bblock_t * block)125 bblock_start(struct bblock_t *block)
126 {
127    return (struct backend_instruction *)exec_list_get_head(&block->instructions);
128 }
129 
130 static inline const struct backend_instruction *
bblock_start_const(const struct bblock_t * block)131 bblock_start_const(const struct bblock_t *block)
132 {
133    return (const struct backend_instruction *)exec_list_get_head_const(&block->instructions);
134 }
135 
136 static inline struct backend_instruction *
bblock_end(struct bblock_t * block)137 bblock_end(struct bblock_t *block)
138 {
139    return (struct backend_instruction *)exec_list_get_tail(&block->instructions);
140 }
141 
142 static inline const struct backend_instruction *
bblock_end_const(const struct bblock_t * block)143 bblock_end_const(const struct bblock_t *block)
144 {
145    return (const struct backend_instruction *)exec_list_get_tail_const(&block->instructions);
146 }
147 
148 static inline struct bblock_t *
bblock_next(struct bblock_t * block)149 bblock_next(struct bblock_t *block)
150 {
151    if (exec_node_is_tail_sentinel(block->link.next))
152       return NULL;
153 
154    return (struct bblock_t *)block->link.next;
155 }
156 
157 static inline const struct bblock_t *
bblock_next_const(const struct bblock_t * block)158 bblock_next_const(const struct bblock_t *block)
159 {
160    if (exec_node_is_tail_sentinel(block->link.next))
161       return NULL;
162 
163    return (const struct bblock_t *)block->link.next;
164 }
165 
166 static inline struct bblock_t *
bblock_prev(struct bblock_t * block)167 bblock_prev(struct bblock_t *block)
168 {
169    if (exec_node_is_head_sentinel(block->link.prev))
170       return NULL;
171 
172    return (struct bblock_t *)block->link.prev;
173 }
174 
175 static inline const struct bblock_t *
bblock_prev_const(const struct bblock_t * block)176 bblock_prev_const(const struct bblock_t *block)
177 {
178    if (exec_node_is_head_sentinel(block->link.prev))
179       return NULL;
180 
181    return (const struct bblock_t *)block->link.prev;
182 }
183 
184 static inline bool
bblock_starts_with_control_flow(const struct bblock_t * block)185 bblock_starts_with_control_flow(const struct bblock_t *block)
186 {
187    enum opcode op = bblock_start_const(block)->opcode;
188    return op == BRW_OPCODE_DO || op == BRW_OPCODE_ENDIF;
189 }
190 
191 static inline bool
bblock_ends_with_control_flow(const struct bblock_t * block)192 bblock_ends_with_control_flow(const struct bblock_t *block)
193 {
194    enum opcode op = bblock_end_const(block)->opcode;
195    return op == BRW_OPCODE_IF ||
196           op == BRW_OPCODE_ELSE ||
197           op == BRW_OPCODE_WHILE ||
198           op == BRW_OPCODE_BREAK ||
199           op == BRW_OPCODE_CONTINUE;
200 }
201 
202 static inline struct backend_instruction *
bblock_first_non_control_flow_inst(struct bblock_t * block)203 bblock_first_non_control_flow_inst(struct bblock_t *block)
204 {
205    struct backend_instruction *inst = bblock_start(block);
206    if (bblock_starts_with_control_flow(block))
207 #ifdef __cplusplus
208       inst = (struct backend_instruction *)inst->next;
209 #else
210       inst = (struct backend_instruction *)inst->link.next;
211 #endif
212    return inst;
213 }
214 
215 static inline struct backend_instruction *
bblock_last_non_control_flow_inst(struct bblock_t * block)216 bblock_last_non_control_flow_inst(struct bblock_t *block)
217 {
218    struct backend_instruction *inst = bblock_end(block);
219    if (bblock_ends_with_control_flow(block))
220 #ifdef __cplusplus
221       inst = (struct backend_instruction *)inst->prev;
222 #else
223       inst = (struct backend_instruction *)inst->link.prev;
224 #endif
225    return inst;
226 }
227 
228 #ifdef __cplusplus
229 inline backend_instruction *
start()230 bblock_t::start()
231 {
232    return bblock_start(this);
233 }
234 
235 inline const backend_instruction *
start()236 bblock_t::start() const
237 {
238    return bblock_start_const(this);
239 }
240 
241 inline backend_instruction *
end()242 bblock_t::end()
243 {
244    return bblock_end(this);
245 }
246 
247 inline const backend_instruction *
end()248 bblock_t::end() const
249 {
250    return bblock_end_const(this);
251 }
252 
253 inline bblock_t *
next()254 bblock_t::next()
255 {
256    return bblock_next(this);
257 }
258 
259 inline const bblock_t *
next()260 bblock_t::next() const
261 {
262    return bblock_next_const(this);
263 }
264 
265 inline bblock_t *
prev()266 bblock_t::prev()
267 {
268    return bblock_prev(this);
269 }
270 
271 inline const bblock_t *
prev()272 bblock_t::prev() const
273 {
274    return bblock_prev_const(this);
275 }
276 
277 inline bool
starts_with_control_flow()278 bblock_t::starts_with_control_flow() const
279 {
280    return bblock_starts_with_control_flow(this);
281 }
282 
283 inline bool
ends_with_control_flow()284 bblock_t::ends_with_control_flow() const
285 {
286    return bblock_ends_with_control_flow(this);
287 }
288 
289 inline backend_instruction *
first_non_control_flow_inst()290 bblock_t::first_non_control_flow_inst()
291 {
292    return bblock_first_non_control_flow_inst(this);
293 }
294 
295 inline backend_instruction *
last_non_control_flow_inst()296 bblock_t::last_non_control_flow_inst()
297 {
298    return bblock_last_non_control_flow_inst(this);
299 }
300 #endif
301 
302 struct cfg_t {
303 #ifdef __cplusplus
304    DECLARE_RALLOC_CXX_OPERATORS(cfg_t)
305 
306    cfg_t(const backend_shader *s, exec_list *instructions);
307    ~cfg_t();
308 
309    void remove_block(bblock_t *block);
310 
311    bblock_t *first_block();
312    const bblock_t *first_block() const;
313    bblock_t *last_block();
314    const bblock_t *last_block() const;
315 
316    bblock_t *new_block();
317    void set_next_block(bblock_t **cur, bblock_t *block, int ip);
318    void make_block_array();
319 
320    void dump();
321    void dump_cfg();
322 #endif
323    const struct backend_shader *s;
324    void *mem_ctx;
325 
326    /** Ordered list (by ip) of basic blocks */
327    struct exec_list block_list;
328    struct bblock_t **blocks;
329    int num_blocks;
330 };
331 
332 static inline struct bblock_t *
cfg_first_block(struct cfg_t * cfg)333 cfg_first_block(struct cfg_t *cfg)
334 {
335    return (struct bblock_t *)exec_list_get_head(&cfg->block_list);
336 }
337 
338 static inline const struct bblock_t *
cfg_first_block_const(const struct cfg_t * cfg)339 cfg_first_block_const(const struct cfg_t *cfg)
340 {
341    return (const struct bblock_t *)exec_list_get_head_const(&cfg->block_list);
342 }
343 
344 static inline struct bblock_t *
cfg_last_block(struct cfg_t * cfg)345 cfg_last_block(struct cfg_t *cfg)
346 {
347    return (struct bblock_t *)exec_list_get_tail(&cfg->block_list);
348 }
349 
350 static inline const struct bblock_t *
cfg_last_block_const(const struct cfg_t * cfg)351 cfg_last_block_const(const struct cfg_t *cfg)
352 {
353    return (const struct bblock_t *)exec_list_get_tail_const(&cfg->block_list);
354 }
355 
356 #ifdef __cplusplus
357 inline bblock_t *
first_block()358 cfg_t::first_block()
359 {
360    return cfg_first_block(this);
361 }
362 
363 const inline bblock_t *
first_block()364 cfg_t::first_block() const
365 {
366    return cfg_first_block_const(this);
367 }
368 
369 inline bblock_t *
last_block()370 cfg_t::last_block()
371 {
372    return cfg_last_block(this);
373 }
374 
375 const inline bblock_t *
last_block()376 cfg_t::last_block() const
377 {
378    return cfg_last_block_const(this);
379 }
380 #endif
381 
382 /* Note that this is implemented with a double for loop -- break will
383  * break from the inner loop only!
384  */
385 #define foreach_block_and_inst(__block, __type, __inst, __cfg) \
386    foreach_block (__block, __cfg)                              \
387       foreach_inst_in_block (__type, __inst, __block)
388 
389 /* Note that this is implemented with a double for loop -- break will
390  * break from the inner loop only!
391  */
392 #define foreach_block_and_inst_safe(__block, __type, __inst, __cfg) \
393    foreach_block_safe (__block, __cfg)                              \
394       foreach_inst_in_block_safe (__type, __inst, __block)
395 
396 #define foreach_block(__block, __cfg)                          \
397    foreach_list_typed (bblock_t, __block, link, &(__cfg)->block_list)
398 
399 #define foreach_block_reverse(__block, __cfg)                  \
400    foreach_list_typed_reverse (bblock_t, __block, link, &(__cfg)->block_list)
401 
402 #define foreach_block_safe(__block, __cfg)                     \
403    foreach_list_typed_safe (bblock_t, __block, link, &(__cfg)->block_list)
404 
405 #define foreach_block_reverse_safe(__block, __cfg)             \
406    foreach_list_typed_reverse_safe (bblock_t, __block, link, &(__cfg)->block_list)
407 
408 #define foreach_inst_in_block(__type, __inst, __block)         \
409    foreach_in_list(__type, __inst, &(__block)->instructions)
410 
411 #define foreach_inst_in_block_safe(__type, __inst, __block)    \
412    for (__type *__inst = (__type *)__block->instructions.head_sentinel.next, \
413                *__next = (__type *)__inst->next;               \
414         __next != NULL;                                        \
415         __inst = __next,                                       \
416         __next = (__type *)__next->next)
417 
418 #define foreach_inst_in_block_reverse(__type, __inst, __block) \
419    foreach_in_list_reverse(__type, __inst, &(__block)->instructions)
420 
421 #define foreach_inst_in_block_reverse_safe(__type, __inst, __block) \
422    foreach_in_list_reverse_safe(__type, __inst, &(__block)->instructions)
423 
424 #define foreach_inst_in_block_starting_from(__type, __scan_inst, __inst) \
425    for (__type *__scan_inst = (__type *)__inst->next;          \
426         !__scan_inst->is_tail_sentinel();                      \
427         __scan_inst = (__type *)__scan_inst->next)
428 
429 #define foreach_inst_in_block_reverse_starting_from(__type, __scan_inst, __inst) \
430    for (__type *__scan_inst = (__type *)__inst->prev;          \
431         !__scan_inst->is_head_sentinel();                      \
432         __scan_inst = (__type *)__scan_inst->prev)
433 
434 #ifdef __cplusplus
435 namespace brw {
436    /**
437     * Immediate dominator tree analysis of a shader.
438     */
439    struct idom_tree {
440       idom_tree(const backend_shader *s);
441       ~idom_tree();
442 
443       bool
validateidom_tree444       validate(const backend_shader *) const
445       {
446          /* FINISHME */
447          return true;
448       }
449 
450       analysis_dependency_class
dependency_classidom_tree451       dependency_class() const
452       {
453          return DEPENDENCY_BLOCKS;
454       }
455 
456       const bblock_t *
parentidom_tree457       parent(const bblock_t *b) const
458       {
459          assert(unsigned(b->num) < num_parents);
460          return parents[b->num];
461       }
462 
463       bblock_t *
parentidom_tree464       parent(bblock_t *b) const
465       {
466          assert(unsigned(b->num) < num_parents);
467          return parents[b->num];
468       }
469 
470       bblock_t *
471       intersect(bblock_t *b1, bblock_t *b2) const;
472 
473       void
474       dump() const;
475 
476    private:
477       unsigned num_parents;
478       bblock_t **parents;
479    };
480 }
481 #endif
482 
483 #endif /* BRW_CFG_H */
484