2 * Copyright (C) 1995-2010 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
26 #ifndef FIRM_ANA_IRMEMORY_H
27 #define FIRM_ANA_IRMEMORY_H
29 #include "firm_types.h"
33 * @defgroup ir_memory Memory Disambiguator
35 * A memory disambiguator checks wether 2 given SSA values representing
41 /** The alias relation of two memory addresses. */
42 typedef enum ir_alias_relation {
43 ir_no_alias, /**< No alias. */
44 ir_may_alias, /**< Unknown state, may alias. */
45 ir_sure_alias /**< Sure alias. */
48 /** The state of the entity usage flags. */
49 typedef enum ir_entity_usage_computed_state {
50 ir_entity_usage_not_computed,
51 ir_entity_usage_computed
52 } ir_entity_usage_computed_state;
54 /** Possible options for the memory disambiguator. */
55 typedef enum ir_disambuigator_options {
56 aa_opt_no_opt = 0, /**< no options: most conservative */
57 aa_opt_type_based = 1, /**< use type based alias analysis: strict typed source language */
58 aa_opt_byte_type_may_alias = 2, /**< if type based analysis is enabled: bytes types may alias other types */
59 aa_opt_no_alias_args = 4, /**< arguments do not alias each other but may alias global storage */
60 aa_opt_no_alias_args_global = 8, /**< arguments do not alias global storage */
61 aa_opt_no_alias = 16, /**< two addresses NEVER alias, use with CAUTION (gcc -fno-alias) */
62 aa_opt_inherited = 128 /**< only for implementation: options from a graph are inherited from global */
63 } ir_disambuigator_options;
64 ENUM_BITSET(ir_disambuigator_options)
67 * Classify storage locations.
68 * Except ir_sc_pointer they are all disjoint.
69 * ir_sc_pointer potentially aliases all classes which don't have a
72 typedef enum ir_storage_class_class_t {
73 ir_sc_pointer = 0x0, /**< generic pointer, may be anything */
74 ir_sc_globalvar = 0x1, /**< an address of a global variable */
75 ir_sc_localvar = 0x2, /**< an address of a local variable or method argument */
76 ir_sc_tls = 0x3, /**< an address of a thread local storage variable */
77 ir_sc_malloced = 0x4, /**< an allocated heap address */
78 ir_sc_globaladdr = 0x5, /**< a constant address of something */
80 ir_sc_modifier_nottaken = 0x80, /**< if set, the address of the variable was not taken */
81 ir_sc_modifier_argument = 0x40, /**< if set pointer was a function argument */
82 ir_sc_modifiers = ir_sc_modifier_nottaken | ir_sc_modifier_argument
83 } ir_storage_class_class_t;
84 ENUM_BITSET(ir_storage_class_class_t)
86 /** Get the base storage class (ignore modifier) */
87 FIRM_API ir_storage_class_class_t get_base_sc(ir_storage_class_class_t x);
90 * A source language specific memory disambiguator function.
91 * Called by get_alias_relation().
93 typedef ir_alias_relation (*DISAMBIGUATOR_FUNC)(
94 const ir_node *adr1, const ir_mode *mode1,
95 const ir_node *adr2, const ir_mode *mode2);
98 * Classify a base pointer.
100 * @param irn the node representing the base address
101 * @param ent the base entity of the base address iff any
103 FIRM_API ir_storage_class_class_t classify_pointer(const ir_node *irn,
104 const ir_entity *ent);
107 * Returns a human readable name for an alias relation.
109 FIRM_API const char *get_ir_alias_relation_name(ir_alias_relation rel);
112 * Determine the alias relation between two addresses.
114 * @param adr1 The first address.
115 * @param mode1 The mode of the first memory access.
116 * @param adr2 The second address.
117 * @param mode2 The mode of the second memory access.
119 * The memory disambiguator tries to determine the alias state between
120 * two memory addresses. The following rules are used:
122 * - different variable from the same segment never alias (R1 a)
123 * - variables from different segments never alias when:
124 * - a global variable and a local one never alias (R1 b)
125 * - a global variable and a TLS one never alias (R1 c)
126 * - a local variable and a TLS one never alias (R1 d)
127 * - a local variable and a parameter never alias (R1 e)
128 * - a global variable and the result of a malloc routine never alias (R1 f)
129 * - a local variable and the result of a malloc routine never alias (R1 g)
130 * - a TLS variable and the result of a malloc routine never alias (R1 h)
131 * - a parameter and the result of a malloc routine (obtained in the
132 * same routine as the parameter) never alias (R1 i)
133 * - two different variables never alias (R2)
134 * - if one is a variable whose address has never been taken
135 * there is no alias (R3)
136 * - if two memory addresses have the same base and their offsets
137 * do not describe overlapping regions there is no alias (R4)
138 * - if opt_strong_typed is set and both addresses describe entities,
139 * different types never alias (R5)
141 * If none of these rules apply, the points-to framework must be
142 * interrogated to detect the alias relation.
144 FIRM_API ir_alias_relation get_alias_relation(
145 const ir_node *adr1, const ir_mode *mode1,
146 const ir_node *adr2, const ir_mode *mode2);
149 * Set a source language specific memory disambiguator function.
151 * @param func The callback.
153 FIRM_API void set_language_memory_disambiguator(DISAMBIGUATOR_FUNC func);
156 * Initialize the relation cache.
158 FIRM_API void mem_disambig_init(void);
161 * Determine the alias relation between two addresses and
164 * @param irg The current graph.
165 * @param adr1 The first address.
166 * @param mode1 The mode of the first memory access.
167 * @param adr2 The second address.
168 * @param mode2 The mode of the second memory access.
170 * @see get_alias_relation()
172 FIRM_API ir_alias_relation get_alias_relation_ex(
173 const ir_node *adr1, const ir_mode *mode1,
174 const ir_node *adr2, const ir_mode *mode2);
177 * Free the relation cache.
179 FIRM_API void mem_disambig_term(void);
182 * Assure that the entity usage flags have been computed for the given graph.
184 * This analysis computes the entity usage state for all local variables.
186 * Even then the information is not cleaned from the variables, call
187 * assure_irg_entity_usage_computed() again for recomputation.
189 FIRM_API void assure_irg_entity_usage_computed(ir_graph *irg);
192 * Returns the current address taken state of the globals.
194 FIRM_API ir_entity_usage_computed_state get_irp_globals_entity_usage_state(void);
197 * Sets the current address taken state of the globals.
199 * @param state the new state
201 FIRM_API void set_irp_globals_entity_usage_state(ir_entity_usage_computed_state state);
204 * Assure that the address taken flag is computed for the global and TLS entities (variables).
206 * This is an interprocedural analysis that computes the address_taken state
207 * for all global and TLS variables.
209 * Note that this is a conservative estimation that by no Firm transformation
210 * can be invalidated, so it's only recomputed if manually triggered by calling
211 * set_irp_globals_entity_usage_state(ir_entity_usage_not_computed).
212 * Even then the information is not cleaned from the variables, call
213 * assure_irp_globals_entity_usage_computed() again for recomputation.
215 FIRM_API void assure_irp_globals_entity_usage_computed(void);
218 * Get the memory disambiguator options for a graph.
220 * @param irg the graph
222 FIRM_API unsigned get_irg_memory_disambiguator_options(const ir_graph *irg);
225 * Set the memory disambiguator options for a graph.
227 * @param irg the graph
228 * @param options a set of options
230 FIRM_API void set_irg_memory_disambiguator_options(ir_graph *irg,
234 * Set the global disambiguator options for all graphs not having local options.
236 * @param options a set of options
238 FIRM_API void set_irp_memory_disambiguator_options(unsigned options);
241 * Mark all private methods, i.e. those of which all call sites are known.
242 * We use a very convervative estimation yet: If the address of a method is
243 * never taken AND its visibility is visibility_local, then it's private.
245 FIRM_API void mark_private_methods(void);
248 * Creates an ir_prog pass for mark_private_methods().
250 * @param name the name of this pass or NULL
252 * @return the newly created ir_prog pass
254 FIRM_API ir_prog_pass_t *mark_private_methods_pass(const char *name);