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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.h
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 "compiler/glsl_types.h"
35 
36 struct assignment_entry {
37    exec_node link;
38    ir_assignment *assign;
39 };
40 
41 class ir_variable_refcount_entry
42 {
43 public:
44    ir_variable_refcount_entry(ir_variable *var);
45 
46    ir_variable *var; /* The key: the variable's pointer. */
47 
48    /**
49     * List of assignments to the variable, if any.
50     * This is intended to be used for dead code optimisation and may
51     * not be a complete list.
52     */
53    exec_list assign_list;
54 
55    /** Number of times the variable is referenced, including assignments. */
56    unsigned referenced_count;
57 
58    /** Number of times the variable is assigned. */
59    unsigned assigned_count;
60 
61    bool declaration; /* If the variable had a decl in the instruction stream */
62 };
63 
64 class ir_variable_refcount_visitor : public ir_hierarchical_visitor {
65 public:
66    ir_variable_refcount_visitor(void);
67    ~ir_variable_refcount_visitor(void);
68 
69    virtual ir_visitor_status visit(ir_variable *);
70    virtual ir_visitor_status visit(ir_dereference_variable *);
71 
72    virtual ir_visitor_status visit_enter(ir_function_signature *);
73    virtual ir_visitor_status visit_leave(ir_assignment *);
74 
75    /**
76     * Find variable in the hash table, and insert it if not present
77     */
78    ir_variable_refcount_entry *get_variable_entry(ir_variable *var);
79 
80    /**
81     * Hash table mapping ir_variable to ir_variable_refcount_entry.
82     */
83    struct hash_table *ht;
84 
85    void *mem_ctx;
86 };
87