1 /*
2 * Copyright © 2010 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
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24 /**
25 * \file ir_basic_block.cpp
26 *
27 * Basic block analysis of instruction streams.
28 */
29
30 #include "ir.h"
31 #include "ir_visitor.h"
32 #include "ir_basic_block.h"
33 #include "glsl_types.h"
34
35 /**
36 * Calls a user function for every basic block in the instruction stream.
37 *
38 * Basic block analysis is pretty easy in our IR thanks to the lack of
39 * unstructured control flow. We've got:
40 *
41 * ir_loop (for () {}, while () {}, do {} while ())
42 * ir_loop_jump (
43 * ir_if () {}
44 * ir_return
45 * ir_call()
46 *
47 * Note that the basic blocks returned by this don't encompass all
48 * operations performed by the program -- for example, if conditions
49 * don't get returned, nor do the assignments that will be generated
50 * for ir_call parameters.
51 */
call_for_basic_blocks(exec_list * instructions,void (* callback)(ir_instruction * first,ir_instruction * last,void * data),void * data)52 void call_for_basic_blocks(exec_list *instructions,
53 void (*callback)(ir_instruction *first,
54 ir_instruction *last,
55 void *data),
56 void *data)
57 {
58 ir_instruction *leader = NULL;
59 ir_instruction *last = NULL;
60
61 foreach_iter(exec_list_iterator, iter, *instructions) {
62 ir_instruction *ir = (ir_instruction *)iter.get();
63 ir_if *ir_if;
64 ir_loop *ir_loop;
65 ir_function *ir_function;
66
67 if (!leader)
68 leader = ir;
69
70 if ((ir_if = ir->as_if())) {
71 callback(leader, ir, data);
72 leader = NULL;
73
74 call_for_basic_blocks(&ir_if->then_instructions, callback, data);
75 call_for_basic_blocks(&ir_if->else_instructions, callback, data);
76 } else if ((ir_loop = ir->as_loop())) {
77 callback(leader, ir, data);
78 leader = NULL;
79 call_for_basic_blocks(&ir_loop->body_instructions, callback, data);
80 } else if (ir->as_return() || ir->as_call()) {
81 callback(leader, ir, data);
82 leader = NULL;
83 } else if ((ir_function = ir->as_function())) {
84 /* A function definition doesn't interrupt our basic block
85 * since execution doesn't go into it. We should process the
86 * bodies of its signatures for BBs, though.
87 *
88 * Note that we miss an opportunity for producing more
89 * maximal BBs between the instructions that precede main()
90 * and the body of main(). Perhaps those instructions ought
91 * to live inside of main().
92 */
93 foreach_iter(exec_list_iterator, fun_iter, *ir_function) {
94 ir_function_signature *ir_sig;
95
96 ir_sig = (ir_function_signature *)fun_iter.get();
97
98 call_for_basic_blocks(&ir_sig->body, callback, data);
99 }
100 }
101 last = ir;
102 }
103 if (leader) {
104 callback(leader, last, data);
105 }
106 }
107