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_variable_refcount.cpp
26 *
27 * Provides a visitor which produces a list of variables referenced,
28 * how many times they were referenced and assigned, and whether they
29 * were defined in the scope.
30 */
31
32#include "ir.h"
33#include "ir_visitor.h"
34#include "ir_variable_refcount.h"
35#include "glsl_types.h"
36
37
38// constructor
39ir_variable_refcount_entry::ir_variable_refcount_entry(ir_variable *var)
40{
41   this->var = var;
42   assign = NULL;
43   assigned_count = 0;
44   declaration = false;
45   referenced_count = 0;
46}
47
48
49ir_variable_refcount_entry *
50ir_variable_refcount_visitor::get_variable_entry(ir_variable *var)
51{
52   assert(var);
53   foreach_iter(exec_list_iterator, iter, this->variable_list) {
54      ir_variable_refcount_entry *entry = (ir_variable_refcount_entry *)iter.get();
55      if (entry->var == var)
56	 return entry;
57   }
58
59   ir_variable_refcount_entry *entry = new(mem_ctx) ir_variable_refcount_entry(var);
60   assert(entry->referenced_count == 0);
61   this->variable_list.push_tail(entry);
62   return entry;
63}
64
65
66ir_visitor_status
67ir_variable_refcount_visitor::visit(ir_variable *ir)
68{
69   ir_variable_refcount_entry *entry = this->get_variable_entry(ir);
70   if (entry)
71      entry->declaration = true;
72
73   return visit_continue;
74}
75
76
77ir_visitor_status
78ir_variable_refcount_visitor::visit(ir_dereference_variable *ir)
79{
80   ir_variable *const var = ir->variable_referenced();
81   ir_variable_refcount_entry *entry = this->get_variable_entry(var);
82
83   if (entry)
84      entry->referenced_count++;
85
86   return visit_continue;
87}
88
89
90ir_visitor_status
91ir_variable_refcount_visitor::visit_enter(ir_function_signature *ir)
92{
93   /* We don't want to descend into the function parameters and
94    * dead-code eliminate them, so just accept the body here.
95    */
96   visit_list_elements(this, &ir->body);
97   return visit_continue_with_parent;
98}
99
100
101ir_visitor_status
102ir_variable_refcount_visitor::visit_leave(ir_assignment *ir)
103{
104   ir_variable_refcount_entry *entry;
105   entry = this->get_variable_entry(ir->lhs->variable_referenced());
106   if (entry) {
107      entry->assigned_count++;
108      if (entry->assign == NULL)
109	 entry->assign = ir;
110   }
111
112   return visit_continue;
113}
114