ir_variable_refcount.cpp revision c8b26c63fdad84d311748a24972146b6a371ab31 
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
37variable_entry *
38ir_variable_refcount_visitor::get_variable_entry(ir_variable *var)
39{
40   assert(var);
41   foreach_iter(exec_list_iterator, iter, this->variable_list) {
42      variable_entry *entry = (variable_entry *)iter.get();
43      if (entry->var == var)
44	 return entry;
45   }
46
47   variable_entry *entry = new(mem_ctx) variable_entry(var);
48   assert(entry->referenced_count == 0);
49   this->variable_list.push_tail(entry);
50   return entry;
51}
52
53
54ir_visitor_status
55ir_variable_refcount_visitor::visit(ir_variable *ir)
56{
57   variable_entry *entry = this->get_variable_entry(ir);
58   if (entry)
59      entry->declaration = true;
60
61   return visit_continue;
62}
63
64
65ir_visitor_status
66ir_variable_refcount_visitor::visit(ir_dereference_variable *ir)
67{
68   ir_variable *const var = ir->variable_referenced();
69   variable_entry *entry = this->get_variable_entry(var);
70
71   if (entry)
72      entry->referenced_count++;
73
74   return visit_continue;
75}
76
77
78ir_visitor_status
79ir_variable_refcount_visitor::visit_enter(ir_function_signature *ir)
80{
81   /* We don't want to descend into the function parameters and
82    * dead-code eliminate them, so just accept the body here.
83    */
84   visit_list_elements(this, &ir->body);
85   return visit_continue_with_parent;
86}
87
88
89ir_visitor_status
90ir_variable_refcount_visitor::visit_leave(ir_assignment *ir)
91{
92   variable_entry *entry;
93   entry = this->get_variable_entry(ir->lhs->variable_referenced());
94   if (entry) {
95      entry->assigned_count++;
96      if (entry->assign == NULL)
97	 entry->assign = ir;
98   }
99
100   return visit_continue;
101}
102