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 opt_dead_functions.cpp
26 *
27 * Eliminates unused functions from the linked program.
28 */
29
30 #include "ir.h"
31 #include "ir_visitor.h"
32 #include "ir_expression_flattening.h"
33 #include "glsl_types.h"
34
35 class signature_entry : public exec_node
36 {
37 public:
signature_entry(ir_function_signature * sig)38 signature_entry(ir_function_signature *sig)
39 {
40 this->signature = sig;
41 this->used = false;
42 }
43
44 ir_function_signature *signature;
45 bool used;
46 };
47
48 class ir_dead_functions_visitor : public ir_hierarchical_visitor {
49 public:
ir_dead_functions_visitor()50 ir_dead_functions_visitor()
51 {
52 this->mem_ctx = hieralloc_new(NULL);
53 }
54
~ir_dead_functions_visitor()55 ~ir_dead_functions_visitor()
56 {
57 hieralloc_free(this->mem_ctx);
58 }
59
60 virtual ir_visitor_status visit_enter(ir_function_signature *);
61 virtual ir_visitor_status visit_enter(ir_call *);
62
63 signature_entry *get_signature_entry(ir_function_signature *var);
64
65 bool (*predicate)(ir_instruction *ir);
66
67 /* List of signature_entry */
68 exec_list signature_list;
69 void *mem_ctx;
70 };
71
72
73 signature_entry *
get_signature_entry(ir_function_signature * sig)74 ir_dead_functions_visitor::get_signature_entry(ir_function_signature *sig)
75 {
76 foreach_iter(exec_list_iterator, iter, this->signature_list) {
77 signature_entry *entry = (signature_entry *)iter.get();
78 if (entry->signature == sig)
79 return entry;
80 }
81
82 signature_entry *entry = new(mem_ctx) signature_entry(sig);
83 this->signature_list.push_tail(entry);
84 return entry;
85 }
86
87
88 ir_visitor_status
visit_enter(ir_function_signature * ir)89 ir_dead_functions_visitor::visit_enter(ir_function_signature *ir)
90 {
91 signature_entry *entry = this->get_signature_entry(ir);
92
93 if (strcmp(ir->function_name(), "main") == 0) {
94 entry->used = true;
95 }
96
97 return visit_continue;
98 }
99
100
101 ir_visitor_status
visit_enter(ir_call * ir)102 ir_dead_functions_visitor::visit_enter(ir_call *ir)
103 {
104 signature_entry *entry = this->get_signature_entry(ir->get_callee());
105
106 entry->used = true;
107
108 return visit_continue;
109 }
110
111 bool
do_dead_functions(exec_list * instructions)112 do_dead_functions(exec_list *instructions)
113 {
114 ir_dead_functions_visitor v;
115 bool progress = false;
116
117 visit_list_elements(&v, instructions);
118
119 /* Now that we've figured out which function signatures are used, remove
120 * the unused ones, and remove function definitions that have no more
121 * signatures.
122 */
123 foreach_iter(exec_list_iterator, iter, v.signature_list) {
124 signature_entry *entry = (signature_entry *)iter.get();
125
126 if (!entry->used) {
127 entry->signature->remove();
128 delete entry->signature;
129 progress = true;
130 }
131 delete(entry);
132 }
133
134 /* We don't just do this above when we nuked a signature because of
135 * const pointers.
136 */
137 foreach_iter(exec_list_iterator, iter, *instructions) {
138 ir_instruction *ir = (ir_instruction *)iter.get();
139 ir_function *func = ir->as_function();
140
141 if (func && func->signatures.is_empty()) {
142 /* At this point (post-linking), the symbol table is no
143 * longer in use, so not removing the function from the
144 * symbol table should be OK.
145 */
146 func->remove();
147 delete func;
148 progress = true;
149 }
150 }
151
152 return progress;
153 }
154