2 * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Memory disambiguator
23 * @author Michael Beck
27 #ifndef FIRM_ANA_IRMEMORY_H
28 #define FIRM_ANA_IRMEMORY_H
30 #include "firm_types.h"
32 /** The alias relation of two memory addresses. */
34 no_alias, /**< No alias. */
35 may_alias, /**< Unknown state, may alias. */
36 sure_alias /**< Sure alias. */
39 /** The state of the address taken flags. */
41 ir_address_taken_not_computed, /**< Address taken flag is not computed. */
42 ir_address_taken_computed /**< Address taken flag is computed. */
43 } ir_address_taken_computed_state;
45 /** Possible options for the memory disambiguator. */
47 aa_opt_no_opt = 0, /**< no options: most conservative */
48 aa_opt_type_based = 1, /**< use type based alias analysis: strict typed source language */
49 aa_opt_byte_type_may_alias = 2, /**< if type based analysis is enabled: bytes types may alias other types */
50 aa_opt_no_alias = 4, /**< two addresses NEVER alias, use with CAUTION (gcc -fno-alias) */
51 aa_opt_inherited = 128 /**< only for implementation: options from a graph are inherited from global */
52 } disambuigator_options;
55 * A source language specific memory disambiguator function.
56 * Called by get_alias_relation().
58 typedef ir_alias_relation (*DISAMBIGUATOR_FUNC)(
60 ir_node *adr1, ir_mode *mode1,
61 ir_node *adr2, ir_mode *mode2);
64 * Determine the alias relation between two addresses.
66 * @param irg The current graph.
67 * @param adr1 The first address.
68 * @param mode1 The mode of the first memory access.
69 * @param adr2 The second address.
70 * @param mode2 The mode of the second memory access.
72 * The memory disambiguator tries to determine the alias state between
73 * two memory addresses. The following rules are used:
75 * - variables from different segments never alias (R1)
76 * - a global variable and a local one never alias (R1 b)
77 * - a global variable and a TLS one never alias (R1 c)
78 * - a local variable and a TLS one never alias (R1 d)
79 * - a local variable and a parameter never alias (R1 e)
80 * - two different variables never alias (R2)
81 * - if one is a variable which address has never taken
82 * there is no alias (R3)
83 * - if two memory addresses have the same base and there offsets
84 * do not describe overlapping regions there is no alias (R4)
85 * - if opt_strong_typed is set and both addresses describe entities,
86 * different types never alias (R5)
88 * If none of these rules apply, the points-to framework must be
89 * interrogated to detect the alias relation.
91 ir_alias_relation get_alias_relation(
93 ir_node *adr1, ir_mode *mode1,
94 ir_node *adr2, ir_mode *mode2);
97 * Set a source language specific memory disambiguator function.
99 * @param func The callback.
101 void set_language_memory_disambiguator(DISAMBIGUATOR_FUNC func);
104 * Initialize the relation cache.
106 void mem_disambig_init(void);
109 * Determine the alias relation between two addresses and
112 * @param irg The current graph.
113 * @param adr1 The first address.
114 * @param mode1 The mode of the first memory access.
115 * @param adr2 The second address.
116 * @param mode2 The mode of the second memory access.
117 * @param options Additional options.
119 * @see get_alias_relation()
121 ir_alias_relation get_alias_relation_ex(
123 ir_node *adr1, ir_mode *mode1,
124 ir_node *adr2, ir_mode *mode2);
127 * Free the relation cache.
129 void mem_disambig_term(void);
132 * Returns the current address taken state of the graph.
134 ir_address_taken_computed_state get_irg_address_taken_state(const ir_graph *irg);
137 * Sets the current address taken state of the graph.
139 * @param irg the graph
140 * @param state the new state
142 void set_irg_address_taken_state(ir_graph *irg, ir_address_taken_computed_state state);
145 * Assure that the address taken flag is computed for the given graph.
147 * This is an intraprocedural analysis that computes the address_taken state
148 * for all local variables.
150 * Note that this is a conservative estimation that by no Firm transformation
151 * can be invalidated, so it's only recomputed if manually triggered by calling
152 * set_irg_address_taken_state(irg, ir_address_taken_not_computed).
153 * Even then the information is not cleaned from the variables, call
154 * assure_irg_address_taken_computed() again for recomputation.
156 void assure_irg_address_taken_computed(ir_graph *irg);
159 * Returns the current address taken state of the globals.
161 ir_address_taken_computed_state get_irp_globals_address_taken_state(void);
164 * Sets the current address taken state of the globals.
166 * @param state the new state
168 void set_irp_globals_address_taken_state(ir_address_taken_computed_state state);
171 * Assure that the address taken flag is computed for the global and TLS entities (variables).
173 * This is an interprocedural analysis that computes the address_taken state
174 * for all global and TLS variables.
176 * Note that this is a conservative estimation that by no Firm transformation
177 * can be invalidated, so it's only recomputed if manually triggered by calling
178 * set_irp_globals_address_taken_state(ir_address_taken_not_computed).
179 * Even then the information is not cleaned from the variables, call
180 * assure_irp_globals_address_taken_computed() again for recomputation.
182 void assure_irp_globals_address_taken_computed(void);
185 * Get the memory disambiguator options for a graph.
187 * @param irg the graph
189 unsigned get_irg_memory_disambiguator_options(ir_graph *irg);
192 * Set the memory disambiguator options for a graph.
194 * @param irg the graph
195 * @param option a set of options
197 void set_irg_memory_disambiguator_options(ir_graph *irg, unsigned options);
200 * Set the global disambiguator options for all graphs not having local options.
202 * @param option a set of options
204 void set_irp_memory_disambiguator_options(unsigned options);
206 #endif /* FIRM_ANA_IRMEMORY_H */