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 ir_no_alias, /**< No alias. */
35 ir_may_alias, /**< Unknown state, may alias. */
36 ir_sure_alias /**< Sure alias. */
39 /** The state of the entity usage flags. */
41 ir_entity_usage_not_computed,
42 ir_entity_usage_computed
43 } ir_entity_usage_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 } ir_disambuigator_options;
55 * Classify storage locations.
56 * Except ir_sc_pointer they are all disjoint.
57 * ir_sc_pointer potentially aliases all classes which don't have a
61 ir_sc_pointer = 0x0, /**< generic pointer, may be anything */
62 ir_sc_globalvar = 0x1, /**< an address of a global variable */
63 ir_sc_localvar = 0x2, /**< an address of a local variable */
64 ir_sc_argument = 0x3, /**< an method argument */
65 ir_sc_tls = 0x4, /**< an address of a thread local storage variable */
66 ir_sc_malloced = 0x5, /**< an allocated heap address */
68 ir_sc_modifier_nottaken = 0x80 /**< if set, the address of the variable was not taken */
69 } ir_storage_class_class_t;
72 * A source language specific memory disambiguator function.
73 * Called by get_alias_relation().
75 typedef ir_alias_relation (*DISAMBIGUATOR_FUNC)(
77 ir_node *adr1, ir_mode *mode1,
78 ir_node *adr2, ir_mode *mode2);
81 * Classify a base pointer.
83 * @param irg the graph of the pointer
84 * @param irn the node representing the base address
85 * @param ent the base entity of the base address iff any
87 ir_storage_class_class_t classify_pointer(ir_graph *irg, ir_node *irn, ir_entity *ent);
90 * Returns a human readable name for an alias relation.
92 const char *get_ir_alias_relation_name(ir_alias_relation rel);
95 * Determine the alias relation between two addresses.
97 * @param irg The current graph.
98 * @param adr1 The first address.
99 * @param mode1 The mode of the first memory access.
100 * @param adr2 The second address.
101 * @param mode2 The mode of the second memory access.
103 * The memory disambiguator tries to determine the alias state between
104 * two memory addresses. The following rules are used:
106 * - different variable from the same segment never alias (R1 a)
107 * - variables from different segments never alias when:
108 * - a global variable and a local one never alias (R1 b)
109 * - a global variable and a TLS one never alias (R1 c)
110 * - a local variable and a TLS one never alias (R1 d)
111 * - a local variable and a parameter never alias (R1 e)
112 * - a global variable and the result of a malloc routine never alias (R1 f)
113 * - a local variable and the result of a malloc routine never alias (R1 g)
114 * - a TLS variable and the result of a malloc routine never alias (R1 h)
115 * - a parameter and the result of a malloc routine (obtained in the
116 * same routine as the parameter) never alias (R1 i)
117 * - two different variables never alias (R2)
118 * - if one is a variable whose address has never been taken
119 * there is no alias (R3)
120 * - if two memory addresses have the same base and their offsets
121 * do not describe overlapping regions there is no alias (R4)
122 * - if opt_strong_typed is set and both addresses describe entities,
123 * different types never alias (R5)
125 * If none of these rules apply, the points-to framework must be
126 * interrogated to detect the alias relation.
128 ir_alias_relation get_alias_relation(
130 ir_node *adr1, ir_mode *mode1,
131 ir_node *adr2, ir_mode *mode2);
134 * Set a source language specific memory disambiguator function.
136 * @param func The callback.
138 void set_language_memory_disambiguator(DISAMBIGUATOR_FUNC func);
141 * Initialize the relation cache.
143 void mem_disambig_init(void);
146 * Determine the alias relation between two addresses and
149 * @param irg The current graph.
150 * @param adr1 The first address.
151 * @param mode1 The mode of the first memory access.
152 * @param adr2 The second address.
153 * @param mode2 The mode of the second memory access.
155 * @see get_alias_relation()
157 ir_alias_relation get_alias_relation_ex(
159 ir_node *adr1, ir_mode *mode1,
160 ir_node *adr2, ir_mode *mode2);
163 * Free the relation cache.
165 void mem_disambig_term(void);
167 ir_entity_usage_computed_state get_irg_entity_usage_state(const ir_graph *irg);
169 void set_irg_entity_usage_state(ir_graph *irg, ir_entity_usage_computed_state state);
172 * Assure that the entity usage flags have been computed for the given graph.
174 * This is an intraprocedural analysis that computes the entity usage state
175 * for all local variables.
177 * Note that this is a conservative estimation that by no Firm transformation
178 * can be invalidated, so it's only recomputed if manually triggered by calling
179 * set_irg_entity_usage_state(irg, ir_entity_usage_not_computed).
180 * Even then the information is not cleaned from the variables, call
181 * assure_irg_entity_usage_computed() again for recomputation.
183 void assure_irg_entity_usage_computed(ir_graph *irg);
186 * Returns the current address taken state of the globals.
188 ir_entity_usage_computed_state get_irp_globals_entity_usage_state(void);
191 * Sets the current address taken state of the globals.
193 * @param state the new state
195 void set_irp_globals_entity_usage_state(ir_entity_usage_computed_state state);
198 * Assure that the address taken flag is computed for the global and TLS entities (variables).
200 * This is an interprocedural analysis that computes the address_taken state
201 * for all global and TLS variables.
203 * Note that this is a conservative estimation that by no Firm transformation
204 * can be invalidated, so it's only recomputed if manually triggered by calling
205 * set_irp_globals_entity_usage_state(ir_entity_usage_not_computed).
206 * Even then the information is not cleaned from the variables, call
207 * assure_irp_globals_entity_usage_computed() again for recomputation.
209 void assure_irp_globals_entity_usage_computed(void);
212 * Get the memory disambiguator options for a graph.
214 * @param irg the graph
216 unsigned get_irg_memory_disambiguator_options(ir_graph *irg);
219 * Set the memory disambiguator options for a graph.
221 * @param irg the graph
222 * @param option a set of options
224 void set_irg_memory_disambiguator_options(ir_graph *irg, unsigned options);
227 * Set the global disambiguator options for all graphs not having local options.
229 * @param option a set of options
231 void set_irp_memory_disambiguator_options(unsigned options);
234 * Mark all private methods, i.e. those of which all call sites are known.
235 * We use a very convervative estimation yet: If the address of a method is
236 * never taken AND its visibility is visibility_local, then it's private.
238 void mark_private_methods(void);
240 #endif /* FIRM_ANA_IRMEMORY_H */