3 * File name: ir/ana/irmemory.c
4 * Purpose: Memory disambiguator
9 * Copyright: (c) 2006-2007 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
19 #include "irgraph_t.h"
29 /** The source language specific language disambiguator function. */
30 static DISAMBIGUATOR_FUNC language_disambuigator = NULL;
32 /** The global memory disambiguator options. */
33 static unsigned global_mem_disamgig_opt = aa_opt_no_opt;
35 /* Get the memory disambiguator options for a graph. */
36 unsigned get_irg_memory_disambiguator_options(ir_graph *irg) {
37 unsigned opt = irg->mem_disambig_opt;
38 if (opt & aa_opt_inherited)
39 return global_mem_disamgig_opt;
41 } /* get_irg_memory_disambiguator_options */
43 /* Set the memory disambiguator options for a graph. */
44 void set_irg_memory_disambiguator_options(ir_graph *irg, unsigned options) {
45 irg->mem_disambig_opt = options & ~aa_opt_inherited;
46 } /* set_irg_memory_disambiguator_options */
48 /* Set the global disambiguator options for all graphs not having local options. */
49 void set_irp_memory_disambiguator_options(unsigned options) {
50 global_mem_disamgig_opt = options;
51 } /* set_irp_memory_disambiguator_options */
54 * Find the base address and entity of an Sel node.
57 * @param pEnt after return points to the base entity.
59 * @return the base address.
61 static ir_node *find_base_adr(ir_node *sel, ir_entity **pEnt) {
62 ir_node *ptr = get_Sel_ptr(sel);
66 ptr = get_Sel_ptr(sel);
68 *pEnt = get_Sel_entity(sel);
73 * Two address expressions have the same base address,
74 * check if there offsets are different.
76 * @param adr1 The first address.
77 * @param adr2 The second address.
79 static ir_alias_relation different_offsets(ir_node *adr1, ir_node *adr2) {
81 } /* different_offsets */
84 * Determine the alias relation by checking if adr1 and adr2 are pointer
87 * @param adr1 The first address.
88 * @param adr2 The second address.
90 static ir_alias_relation different_types(ir_node *adr1, ir_node *adr2)
92 ir_entity *ent1 = NULL, *ent2 = NULL;
94 if (is_SymConst(adr1) && get_SymConst_kind(adr1) == symconst_addr_ent)
95 ent1 = get_SymConst_entity(adr1);
96 else if (is_Sel(adr1))
97 ent1 = get_Sel_entity(adr1);
99 if (is_SymConst(adr2) && get_SymConst_kind(adr2) == symconst_addr_ent)
100 ent2 = get_SymConst_entity(adr2);
101 else if (is_Sel(adr2))
102 ent2 = get_Sel_entity(adr2);
104 if (ent1 != NULL && ent2 != NULL) {
105 ir_type *tp1 = get_entity_type(ent1);
106 ir_type *tp2 = get_entity_type(ent2);
109 if (is_Pointer_type(tp1) && is_Pointer_type(tp2)) {
110 /* do deref until no pointer types are found */
112 tp1 = get_pointer_points_to_type(tp1);
113 tp2 = get_pointer_points_to_type(tp2);
114 } while (is_Pointer_type(tp1) && is_Pointer_type(tp2));
117 if (get_type_tpop(tp1) != get_type_tpop(tp2)) {
118 /* different type structure */
121 if (is_Class_type(tp1)) {
122 /* check class hierarchy */
123 if (! is_SubClass_of(tp1, tp2) &&
124 ! is_SubClass_of(tp2, tp1))
127 /* different types */
133 } /* different_types */
136 * Returns non-zero if a node is a routine parameter.
138 * @param node the node to test
140 static int is_arg_Proj(ir_node *node) {
143 node = get_Proj_pred(node);
146 return pn_Start_T_args == get_Proj_proj(node) && is_Start(get_Proj_pred(node));
150 * Determine the alias relation between two addresses.
152 static ir_alias_relation _get_alias_relation(
154 ir_node *adr1, ir_mode *mode1,
155 ir_node *adr2, ir_mode *mode2)
158 ir_entity *ent1, *ent2;
161 if (! get_opt_alias_analysis())
167 options = get_irg_memory_disambiguator_options(irg);
169 /* The Armageddon switch */
170 if (options & aa_opt_no_alias)
173 /* Two save some code, sort the addresses by its id's. Beware, this
174 might break some things, so better check here. */
175 assert(iro_SymConst < iro_Sel && iro_Sel < iro_Proj && "Code dependence breaked");
176 op1 = get_irn_opcode(adr1);
177 op2 = get_irn_opcode(adr2);
188 if (is_SymConst(adr1) && get_SymConst_kind(adr1) == symconst_addr_ent) {
189 /* first address is a global variable */
191 if (is_SymConst(adr2) && get_SymConst_kind(adr2) == symconst_addr_ent) {
192 /* both addresses are global variables and we know
193 they are different (R1 a) */
194 if (get_SymConst_entity(adr1) != get_SymConst_entity(adr2))
197 /* equal addresses */
202 ir_node *base = find_base_adr(adr2, &ent2);
204 if (is_SymConst(base) && get_SymConst_kind(base) == symconst_addr_ent) {
205 /* base address is a global var (R1 a) */
209 return different_offsets(adr1, adr2);
210 } else if (base == get_irg_frame(irg)) {
211 /* the second one is a local variable so they are always
214 } else if (base == get_irg_tls(irg)) {
215 /* the second one is a TLS variable so they are always
221 /* Here we are: the first is a global var, the second some pointer. */
222 ent1 = get_SymConst_entity(adr1);
223 if (get_entity_address_taken(ent1) == ir_address_not_taken) {
224 /* The address of the global variable was never taken, so
225 the pointer cannot match (R2). */
228 } else if (is_Sel(adr1)) {
229 /* the first address is a Sel */
230 ir_node *base1 = find_base_adr(adr1, &ent1);
232 if (base1 == get_irg_frame(irg)) {
233 /* the first is a local variable */
235 /* the second address is a Sel */
236 ir_node *base2 = find_base_adr(adr2, &ent2);
238 if (base2 == get_irg_frame(irg)) {
239 /* both addresses are local variables and we know
240 they are different (R1 a) */
244 return different_offsets(adr1, adr2);
245 } else if (base2 == get_irg_tls(irg)) {
246 /* the second one is a TLS variable so they are always
249 } else if (is_arg_Proj(base2)) {
250 /* the second one is an offset from a parameter so they are
251 always different (R1 e) */
254 } else if (is_arg_Proj(adr2)) {
255 /* a local variable and a parameter are always different (R1 e) */
258 } else if (base1 == get_irg_tls(irg)) {
259 /* the first is a TLS variable */
261 /* the second address is a Sel */
262 ir_node *base2 = find_base_adr(adr2, &ent2);
264 if (base2 == get_irg_frame(irg)) {
265 /* the second one is a local variable so they are always
268 } else if (base2 == get_irg_tls(irg)) {
269 /* both addresses are TLS variables and we know
270 they are different (R1 a) */
274 return different_offsets(adr1, adr2);
277 } else if (is_arg_Proj(base1)) {
278 /* the first one is an offset from a parameter */
280 /* the second address is a Sel */
281 ir_node *base2 = find_base_adr(adr2, &ent2);
283 if (base2 == get_irg_frame(irg)) {
284 /* the second one is a local variable so they are always
292 if (options & aa_opt_type_based) { /* Type based alias analysis */
293 ir_alias_relation rel;
295 if (options & aa_opt_byte_type_may_alias) {
296 if (get_mode_size_bits(mode1) == 8 || get_mode_size_bits(mode2) == 8) {
297 /* One of the modes address a byte. Assume a may_alias and leave
298 the type based check. */
299 goto leave_type_based_alias;
302 /* cheap check: If the mode sizes did not match, the types MUST be different */
303 if (get_mode_size_bits(mode1) != get_mode_size_bits(mode2))
307 rel = different_types(adr1, adr2);
308 if (rel != may_alias)
310 leave_type_based_alias:;
313 /* do we have a language specific memory disambiguator? */
314 if (language_disambuigator) {
315 ir_alias_relation rel = (*language_disambuigator)(irg, adr1, mode1, adr2, mode2);
316 if (rel != may_alias)
320 /* access points-to information here */
322 } /* _get_alias_relation */
325 * Determine the alias relation between two addresses.
327 ir_alias_relation get_alias_relation(
329 ir_node *adr1, ir_mode *mode1,
330 ir_node *adr2, ir_mode *mode2)
332 ir_alias_relation rel = _get_alias_relation(irg, adr1, mode1, adr2, mode2);
334 } /* get_alias_relation */
336 /* Set a source language specific memory disambiguator function. */
337 void set_language_memory_disambiguator(DISAMBIGUATOR_FUNC func) {
338 language_disambuigator = func;
339 } /* set_language_memory_disambiguator */
341 /** The result cache for the memory disambiguator. */
342 static set *result_cache = NULL;
344 /** An entry in the relation cache. */
345 typedef struct mem_disambig_entry {
346 ir_node *adr1; /**< The first address. */
347 ir_node *adr2; /**< The second address. */
348 ir_alias_relation result; /**< The alias relation result. */
349 } mem_disambig_entry;
351 #define HASH_ENTRY(adr1, adr2) (HASH_PTR(adr1) ^ HASH_PTR(adr2))
354 * Compare two relation cache entries.
356 static int cmp_mem_disambig_entry(const void *elt, const void *key, size_t size) {
357 const mem_disambig_entry *p1 = elt;
358 const mem_disambig_entry *p2 = key;
360 return p1->adr1 == p2->adr1 && p1->adr2 == p2->adr2;
361 } /* cmp_mem_disambig_entry */
364 * Initialize the relation cache.
366 void mem_disambig_init(void) {
367 result_cache = new_set(cmp_mem_disambig_entry, 8);
368 } /* mem_disambig_init */
371 * Determine the alias relation between two addresses.
373 ir_alias_relation get_alias_relation_ex(
375 ir_node *adr1, ir_mode *mode1,
376 ir_node *adr2, ir_mode *mode2)
378 mem_disambig_entry key, *entry;
380 if (! get_opt_alias_analysis())
383 if (get_irn_opcode(adr1) > get_irn_opcode(adr2)) {
391 entry = set_find(result_cache, &key, sizeof(key), HASH_ENTRY(adr1, adr2));
393 return entry->result;
395 key.result = get_alias_relation(irg, adr1, mode1, adr2, mode2);
397 set_insert(result_cache, &key, sizeof(key), HASH_ENTRY(adr1, adr2));
399 } /* get_alias_relation_ex */
401 /* Free the relation cache. */
402 void mem_disambig_term(void) {
404 del_set(result_cache);
407 } /* mem_disambig_term */
410 * Check the mode of a Load/Store with the mode of the entity
412 * If the mode of the entity and the Load/Store mode do not match, we
413 * have the bad reinterpret case:
416 * char b = *(char *)&i;
418 * We do NOT count this as one value and return address_taken
420 * However, we support an often used case. If the mode is two-complement
421 * we allow casts between signed/unsigned.
423 * @param mode the mode of the Load/Store
424 * @param ent_mode the mode of the accessed entity
426 * @return non-zero if the Load/Store is a hidden cast, zero else
428 static int is_hidden_cast(ir_mode *mode, ir_mode *ent_mode) {
429 if (ent_mode != mode) {
430 if (ent_mode == NULL ||
431 get_mode_size_bits(ent_mode) != get_mode_size_bits(mode) ||
432 get_mode_sort(ent_mode) != get_mode_sort(mode) ||
433 get_mode_arithmetic(ent_mode) != irma_twos_complement ||
434 get_mode_arithmetic(mode) != irma_twos_complement)
438 } /* is_hidden_cast */
441 * Determine the address_taken state of a node (or it's successor Sels).
443 * @param irn the node
445 static ir_address_taken_state find_address_taken_state(ir_node *irn) {
447 ir_mode *emode, *mode;
451 for (i = get_irn_n_outs(irn) - 1; i >= 0; --i) {
452 ir_node *succ = get_irn_out(irn, i);
454 switch (get_irn_opcode(succ)) {
456 /* check if this load is not a hidden conversion */
457 mode = get_Load_mode(succ);
458 ent = is_SymConst(irn) ? get_SymConst_entity(irn) : get_Sel_entity(irn);
459 emode = get_type_mode(get_entity_type(ent));
460 if (is_hidden_cast(mode, emode))
461 return ir_address_taken;
465 /* check that the node is not the Store's value */
466 value = get_Store_value(succ);
468 return ir_address_taken;
469 /* check if this Store is not a hidden conversion */
470 mode = get_irn_mode(value);
471 ent = is_SymConst(irn) ? get_SymConst_entity(irn) : get_Sel_entity(irn);
472 emode = get_type_mode(get_entity_type(ent));
473 if (is_hidden_cast(mode, emode))
474 return ir_address_taken;
478 /* Check the successor of irn. */
479 ir_address_taken_state res = find_address_taken_state(succ);
480 if (res != ir_address_not_taken)
486 /* Only the call address is not an address taker but
487 this is an uninteresting case, so we ignore it here. */
488 return ir_address_taken;
491 /* another op, the address may be taken */
492 return ir_address_taken_unknown;
495 /* All successors finished, the address is not taken. */
496 return ir_address_not_taken;
497 } /* find_address_taken_state */
500 * Update the "address taken" flag of all frame entities.
502 static void analyse_irg_address_taken(ir_graph *irg) {
503 ir_type *ft = get_irg_frame_type(irg);
507 /* set initial state to not_taken, as this is the "smallest" state */
508 for (i = get_class_n_members(ft) - 1; i >= 0; --i) {
509 ir_entity *ent = get_class_member(ft, i);
511 set_entity_address_taken(ent, ir_address_not_taken);
514 assure_irg_outs(irg);
516 irg_frame = get_irg_frame(irg);
518 for (i = get_irn_n_outs(irg_frame) - 1; i >= 0; --i) {
519 ir_node *succ = get_irn_out(irg_frame, i);
520 ir_address_taken_state state;
523 ir_entity *ent = get_Sel_entity(succ);
525 if (get_entity_address_taken(ent) == ir_address_taken)
528 state = find_address_taken_state(succ);
529 if (state > get_entity_address_taken(ent))
530 set_entity_address_taken(ent, state);
534 irg->adr_taken_state = ir_address_taken_computed;
535 } /* analyse_address_taken */
537 /* Returns the current address taken state of the graph. */
538 ir_address_taken_computed_state get_irg_address_taken_state(const ir_graph *irg) {
539 return irg->adr_taken_state;
540 } /* get_irg_address_taken_state */
542 /* Sets the current address taken state of the graph. */
543 void set_irg_address_taken_state(ir_graph *irg, ir_address_taken_computed_state state) {
544 irg->adr_taken_state = state;
545 } /* set_irg_address_taken_state */
547 /* Assure that the address taken flag is computed for the given graph. */
548 void assure_irg_address_taken_computed(ir_graph *irg) {
549 if (irg->adr_taken_state == ir_address_taken_not_computed)
550 analyse_irg_address_taken(irg);
551 } /* assure_irg_address_taken_computed */
554 * Initialize the address_taken flag for a global type like type.
556 static void init_taken_flag(ir_type * tp) {
559 /* All external visible entities are at least
560 ir_address_taken_unknown. This is very conservative. */
561 for (i = get_compound_n_members(tp) - 1; i >= 0; --i) {
562 ir_entity *ent = get_compound_member(tp, i);
563 ir_address_taken_state state;
565 state = get_entity_visibility(ent) == visibility_external_visible ?
566 ir_address_taken_unknown : ir_address_not_taken ;
567 set_entity_address_taken(ent, state);
569 } /* init_taken_flag */
573 * Print the address taken state of all entities of a given type for debugging.
575 static void print_address_taken_state(ir_type *tp) {
577 for (i = get_compound_n_members(tp) - 1; i >= 0; --i) {
578 ir_entity *ent = get_compound_member(tp, i);
579 ir_address_taken_state state = get_entity_address_taken(ent);
581 if (state != ir_address_not_taken) {
582 assert(ir_address_not_taken <= state && state <= ir_address_taken);
583 ir_printf("%+F: %s\n", ent, get_address_taken_state_name(state));
586 } /* print_address_taken_state */
590 * Post-walker: check for global entity address
592 static void check_global_address(ir_node *irn, void *env) {
595 ir_address_taken_state state;
597 if (is_SymConst(irn) && get_SymConst_kind(irn) == symconst_addr_ent) {
599 ent = get_SymConst_entity(irn);
600 } else if (is_Sel(irn) && get_Sel_ptr(irn) == tls) {
601 /* A TLS variable. */
602 ent = get_Sel_entity(irn);
606 if (get_entity_address_taken(ent) == ir_address_not_taken) {
607 /* Already at the maximum. */
610 state = find_address_taken_state(irn);
611 if (state > get_entity_address_taken(ent))
612 set_entity_address_taken(ent, state);
613 } /* check_global_address */
616 * Update the "address taken" flag of all global entities.
618 static void analyse_irp_globals_address_taken(void) {
621 init_taken_flag(get_glob_type());
622 init_taken_flag(get_tls_type());
624 for (i = get_irp_n_irgs() - 1; i >= 0; --i) {
625 ir_graph *irg = get_irp_irg(i);
627 assure_irg_outs(irg);
628 irg_walk_graph(irg, NULL, check_global_address, get_irg_tls(irg));
630 //print_address_taken_state(get_glob_type());
631 //print_address_taken_state(get_tls_type());
634 irp->globals_adr_taken_state = ir_address_taken_computed;
635 } /* analyse_irp_globals_address_taken */
637 /* Returns the current address taken state of the globals. */
638 ir_address_taken_computed_state get_irp_globals_address_taken_state(void) {
639 return irp->globals_adr_taken_state;
640 } /* get_irp_globals_address_taken_state */
642 /* Sets the current address taken state of the graph. */
643 void set_irp_globals_address_taken_state(ir_address_taken_computed_state state) {
644 irp->globals_adr_taken_state = state;
645 } /* set_irg_address_taken_state */
647 /* Assure that the address taken flag is computed for the globals. */
648 void assure_irp_globals_address_taken_computed(void) {
649 if (irp->globals_adr_taken_state == ir_address_taken_not_computed)
650 analyse_irp_globals_address_taken();
651 } /* assure_irp_globals_address_taken_computed */