1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/*
* Copyright © 2010 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file ir_variable_refcount.cpp
*
* Provides a visitor which produces a list of variables referenced,
* how many times they were referenced and assigned, and whether they
* were defined in the scope.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "ir_variable_refcount.h"
#include "compiler/glsl_types.h"
#include "util/hash_table.h"
ir_variable_refcount_visitor::ir_variable_refcount_visitor()
{
this->mem_ctx = ralloc_context(NULL);
this->ht = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
_mesa_key_pointer_equal);
}
static void
free_entry(struct hash_entry *entry)
{
ir_variable_refcount_entry *ivre = (ir_variable_refcount_entry *) entry->data;
/* Free assignment list */
exec_node *n;
while ((n = ivre->assign_list.pop_head()) != NULL) {
struct assignment_entry *assignment_entry =
exec_node_data(struct assignment_entry, n, link);
free(assignment_entry);
}
delete ivre;
}
ir_variable_refcount_visitor::~ir_variable_refcount_visitor()
{
ralloc_free(this->mem_ctx);
_mesa_hash_table_destroy(this->ht, free_entry);
}
// constructor
ir_variable_refcount_entry::ir_variable_refcount_entry(ir_variable *var)
{
this->var = var;
assigned_count = 0;
declaration = false;
referenced_count = 0;
}
ir_variable_refcount_entry *
ir_variable_refcount_visitor::get_variable_entry(ir_variable *var)
{
assert(var);
struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
if (e)
return (ir_variable_refcount_entry *)e->data;
ir_variable_refcount_entry *entry = new ir_variable_refcount_entry(var);
assert(entry->referenced_count == 0);
_mesa_hash_table_insert(this->ht, var, entry);
return entry;
}
ir_visitor_status
ir_variable_refcount_visitor::visit(ir_variable *ir)
{
ir_variable_refcount_entry *entry = this->get_variable_entry(ir);
if (entry)
entry->declaration = true;
return visit_continue;
}
ir_visitor_status
ir_variable_refcount_visitor::visit(ir_dereference_variable *ir)
{
ir_variable *const var = ir->variable_referenced();
ir_variable_refcount_entry *entry = this->get_variable_entry(var);
if (entry)
entry->referenced_count++;
return visit_continue;
}
ir_visitor_status
ir_variable_refcount_visitor::visit_enter(ir_function_signature *ir)
{
/* We don't want to descend into the function parameters and
* dead-code eliminate them, so just accept the body here.
*/
visit_list_elements(this, &ir->body);
return visit_continue_with_parent;
}
ir_visitor_status
ir_variable_refcount_visitor::visit_leave(ir_assignment *ir)
{
ir_variable_refcount_entry *entry;
entry = this->get_variable_entry(ir->lhs->variable_referenced());
if (entry) {
entry->assigned_count++;
/* Build a list for dead code optimisation. Don't add assignment if it
* was declared out of scope (outside the instruction stream). Also don't
* bother adding any more to the list if there are more references than
* assignments as this means the variable is used and won't be optimised
* out.
*/
assert(entry->referenced_count >= entry->assigned_count);
if (entry->referenced_count == entry->assigned_count) {
struct assignment_entry *assignment_entry =
(struct assignment_entry *)calloc(1, sizeof(*assignment_entry));
assignment_entry->assign = ir;
entry->assign_list.push_head(&assignment_entry->link);
}
}
return visit_continue;
}
|
