2 * Copyright (C) 1995-2008 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 * Returns a human readable name for an alias relation.
66 const char *get_ir_alias_relation_name(ir_alias_relation rel);
69 * Determine the alias relation between two addresses.
71 * @param irg The current graph.
72 * @param adr1 The first address.
73 * @param mode1 The mode of the first memory access.
74 * @param adr2 The second address.
75 * @param mode2 The mode of the second memory access.
77 * The memory disambiguator tries to determine the alias state between
78 * two memory addresses. The following rules are used:
80 * - variables from different segments never alias (R1)
81 * - a global variable and a local one never alias (R1 b)
82 * - a global variable and a TLS one never alias (R1 c)
83 * - a local variable and a TLS one never alias (R1 d)
84 * - a local variable and a parameter never alias (R1 e)
85 * - two different variables never alias (R2)
86 * - if one is a variable whose address has never been taken
87 * there is no alias (R3)
88 * - if two memory addresses have the same base and their offsets
89 * do not describe overlapping regions there is no alias (R4)
90 * - if opt_strong_typed is set and both addresses describe entities,
91 * different types never alias (R5)
93 * If none of these rules apply, the points-to framework must be
94 * interrogated to detect the alias relation.
96 ir_alias_relation get_alias_relation(
98 ir_node *adr1, ir_mode *mode1,
99 ir_node *adr2, ir_mode *mode2);
102 * Set a source language specific memory disambiguator function.
104 * @param func The callback.
106 void set_language_memory_disambiguator(DISAMBIGUATOR_FUNC func);
109 * Initialize the relation cache.
111 void mem_disambig_init(void);
114 * Determine the alias relation between two addresses and
117 * @param irg The current graph.
118 * @param adr1 The first address.
119 * @param mode1 The mode of the first memory access.
120 * @param adr2 The second address.
121 * @param mode2 The mode of the second memory access.
123 * @see get_alias_relation()
125 ir_alias_relation get_alias_relation_ex(
127 ir_node *adr1, ir_mode *mode1,
128 ir_node *adr2, ir_mode *mode2);
131 * Free the relation cache.
133 void mem_disambig_term(void);
136 * Returns the current address taken state of the graph.
138 ir_address_taken_computed_state get_irg_address_taken_state(const ir_graph *irg);
141 * Sets the current address taken state of the graph.
143 * @param irg the graph
144 * @param state the new state
146 void set_irg_address_taken_state(ir_graph *irg, ir_address_taken_computed_state state);
149 * Assure that the address taken flag is computed for the given graph.
151 * This is an intraprocedural analysis that computes the address_taken state
152 * for all local variables.
154 * Note that this is a conservative estimation that by no Firm transformation
155 * can be invalidated, so it's only recomputed if manually triggered by calling
156 * set_irg_address_taken_state(irg, ir_address_taken_not_computed).
157 * Even then the information is not cleaned from the variables, call
158 * assure_irg_address_taken_computed() again for recomputation.
160 void assure_irg_address_taken_computed(ir_graph *irg);
163 * Returns the current address taken state of the globals.
165 ir_address_taken_computed_state get_irp_globals_address_taken_state(void);
168 * Sets the current address taken state of the globals.
170 * @param state the new state
172 void set_irp_globals_address_taken_state(ir_address_taken_computed_state state);
175 * Assure that the address taken flag is computed for the global and TLS entities (variables).
177 * This is an interprocedural analysis that computes the address_taken state
178 * for all global and TLS variables.
180 * Note that this is a conservative estimation that by no Firm transformation
181 * can be invalidated, so it's only recomputed if manually triggered by calling
182 * set_irp_globals_address_taken_state(ir_address_taken_not_computed).
183 * Even then the information is not cleaned from the variables, call
184 * assure_irp_globals_address_taken_computed() again for recomputation.
186 void assure_irp_globals_address_taken_computed(void);
189 * Get the memory disambiguator options for a graph.
191 * @param irg the graph
193 unsigned get_irg_memory_disambiguator_options(ir_graph *irg);
196 * Set the memory disambiguator options for a graph.
198 * @param irg the graph
199 * @param option a set of options
201 void set_irg_memory_disambiguator_options(ir_graph *irg, unsigned options);
204 * Set the global disambiguator options for all graphs not having local options.
206 * @param option a set of options
208 void set_irp_memory_disambiguator_options(unsigned options);
211 * Mark all private methods, i.e. those of which all call sites are known.
212 * We use a very convervative estimation yet: If the address of a method is
213 * never taken AND its visibility is visibility_local, then it's private.
215 void mark_private_methods(void);
217 #endif /* FIRM_ANA_IRMEMORY_H */