2 * Copyright (C) 1995-2011 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 * File name: ir/opt/escape_ana.c
23 * Purpose: escape analysis and optimization
24 * Author: Michael Beck
28 * Copyright: (c) 1999-2005 Universität Karlsruhe
34 * A fast and simple Escape analysis.
38 #include "iroptimize.h"
40 #include "irgraph_t.h"
45 #include "analyze_irg_args.h"
55 typedef struct walk_env {
56 ir_node *found_allocs; /**< list of all found non-escaped allocs */
57 ir_node *dead_allocs; /**< list of all found dead alloc */
58 check_alloc_entity_func callback; /**< callback that checks a given entity for allocation */
59 unsigned nr_removed; /**< number of removed allocs (placed of frame) */
60 unsigned nr_changed; /**< number of changed allocs (allocated on stack now) */
61 unsigned nr_deads; /**< number of dead allocs */
63 /* these fields are only used in the global escape analysis */
64 ir_graph *irg; /**< the irg for this environment */
65 struct walk_env *next; /**< for linking environments */
70 DEBUG_ONLY(firm_dbg_module_t *dbgHandle;)
73 * checks whether a Raise leaves a method
75 static int is_method_leaving_raise(ir_node *raise)
81 for (i = get_irn_n_outs(raise) - 1; i >= 0; --i) {
82 ir_node *succ = get_irn_out(raise, i);
84 /* there should be only one ProjX node */
85 if (get_Proj_proj(succ) == pn_Raise_X) {
92 /* Hmm: no ProjX from a Raise? This should be a verification
93 * error. For now we just assert and return.
95 panic("No ProjX after Raise found");
98 if (get_irn_n_outs(proj) != 1) {
99 /* Hmm: more than one user of ProjX: This is a verification
102 panic("More than one user of ProjX");
105 n = get_irn_out(proj, 0);
106 assert(is_Block(n) && "Argh: user of ProjX is no block");
108 if (n == get_irg_end_block(get_irn_irg(n)))
111 /* ok, we get here so the raise will not leave the function */
116 * returns an Alloc node if the node adr Select
119 static ir_node *is_depend_alloc(ir_node *adr)
126 /* should be a simple Sel */
127 if (get_Sel_n_indexs(adr) != 0)
130 alloc = skip_Proj(get_Sel_ptr(adr));
131 if (!is_Alloc(alloc))
134 /* hmm, we depend on this Alloc */
135 ir_printf("depend alloc %+F\n", alloc);
141 * determine if a value calculated by n "escape", ie
142 * is stored somewhere we could not track
144 static int can_escape(ir_node *n)
148 /* should always be pointer mode or we made some mistake */
149 assert(mode_is_reference(get_irn_mode(n)));
151 for (i = get_irn_n_outs(n) - 1; i >= 0; --i) {
152 ir_node *succ = get_irn_out(n, i);
154 switch (get_irn_opcode(succ)) {
156 if (get_Store_value(succ) == n) {
157 ir_node *adr = get_Store_ptr(succ);
160 * if this Alloc depends on another one,
163 if (is_depend_alloc(adr))
167 * We are storing n. As long as we do not further
168 * evaluate things, the pointer 'escape' here
176 * Should not happen, but if it does we leave the pointer
177 * path and do not track further
181 case iro_Call: { /* most complicated case */
182 ir_node *ptr = get_Call_ptr(succ);
185 if (is_SymConst_addr_ent(ptr)) {
186 ent = get_SymConst_entity(ptr);
188 /* we know the called entity */
189 for (j = get_Call_n_params(succ) - 1; j >= 0; --j) {
190 if (get_Call_param(succ, j) == n) {
191 /* n is the j'th param of the call */
192 if (get_method_param_access(ent, j) & ptr_access_store)
193 /* n is store in ent */
198 else if (is_Sel(ptr)) {
199 /* go through all possible callees */
200 for (k = get_Call_n_callees(succ) - 1; k >= 0; --k) {
201 ent = get_Call_callee(succ, k);
203 if (ent == unknown_entity) {
204 /* we don't know what will be called, a possible escape */
208 for (j = get_Call_n_params(succ) - 1; j >= 0; --j) {
209 if (get_Call_param(succ, j) == n) {
210 /* n is the j'th param of the call */
211 if (get_method_param_access(ent, j) & ptr_access_store)
212 /* n is store in ent */
218 else /* we don't know want will called */
225 /* Bad: the allocate object is returned */
229 /* Hmm: if we do NOT leave the method, it's local */
230 if (is_method_leaving_raise(succ))
237 /* Bad: trace the tuple backwards */
238 for (j = get_irn_arity(succ) - 1; j >= 0; --j)
239 if (get_irn_n(succ, j) == n)
245 for (k = get_irn_n_outs(succ); k >= 0; --k) {
246 proj = get_irn_out(succ, k);
248 if (get_Proj_proj(proj) == j) {
249 /* we found the right Proj */
256 * If we haven't found the right Proj, succ is still
257 * the Tuple and the search will end here.
267 if (! mode_is_reference(get_irn_mode(succ)))
270 if (can_escape(succ))
277 * walker: search for Alloc nodes and follow the usages
279 static void find_allocations(ir_node *alloc, void *ctx)
281 walk_env_t *env = (walk_env_t*)ctx;
285 if (! is_Alloc(alloc))
288 /* we searching only for heap allocations */
289 if (get_Alloc_where(alloc) != heap_alloc)
293 for (i = get_irn_n_outs(alloc) - 1; i >= 0; --i) {
294 ir_node *proj = get_irn_out(alloc, i);
296 if (get_Proj_proj(proj) == pn_Alloc_res) {
304 * bad: no-one wants the result, should NOT happen but
305 * if it does we could delete it.
307 set_irn_link(alloc, env->dead_allocs);
308 env->dead_allocs = alloc;
313 if (! can_escape(adr)) {
314 set_irn_link(alloc, env->found_allocs);
315 env->found_allocs = alloc;
320 * walker: search for allocation Call nodes and follow the usages
322 static void find_allocation_calls(ir_node *call, void *ctx)
324 walk_env_t *env = (walk_env_t*)ctx;
331 adr = get_Call_ptr(call);
332 if (! is_SymConst_addr_ent(adr))
334 ent = get_SymConst_entity(adr);
335 if (! env->callback(ent))
339 for (i = get_irn_n_outs(call) - 1; i >= 0; --i) {
340 ir_node *res_proj = get_irn_out(call, i);
342 if (get_Proj_proj(res_proj) == pn_Call_T_result) {
343 for (i = get_irn_n_outs(res_proj) - 1; i >= 0; --i) {
344 ir_node *proj = get_irn_out(res_proj, i);
346 if (get_Proj_proj(proj) == 0) {
347 /* found first result */
358 * bad: no-one wants the result, should NOT happen but
359 * if it does we could delete it.
361 set_irn_link(call, env->dead_allocs);
362 env->dead_allocs = call;
367 if (! can_escape(adr)) {
368 set_irn_link(call, env->found_allocs);
369 env->found_allocs = call;
374 * Do the necessary graph transformations to transform
377 static void transform_allocs(ir_graph *irg, walk_env_t *env)
379 ir_node *alloc, *next, *mem, *sel, *size, *blk;
380 ir_type *ftp, *atp, *tp;
386 /* kill all dead allocs */
387 for (alloc = env->dead_allocs; alloc; alloc = next) {
388 next = (ir_node*)get_irn_link(alloc);
390 DBG((dbgHandle, LEVEL_1, "%+F allocation of %+F unused, deleted.\n", irg, alloc));
392 mem = get_Alloc_mem(alloc);
393 blk = get_nodes_block(alloc);
394 turn_into_tuple(alloc, pn_Alloc_max);
395 set_Tuple_pred(alloc, pn_Alloc_M, mem);
396 set_Tuple_pred(alloc, pn_Alloc_X_regular, new_r_Jmp(blk));
397 set_Tuple_pred(alloc, pn_Alloc_X_except, new_r_Bad(irg));
402 /* convert all non-escaped heap allocs into frame variables */
403 ftp = get_irg_frame_type(irg);
404 for (alloc = env->found_allocs; alloc; alloc = next) {
405 next = (ir_node*)get_irn_link(alloc);
406 size = get_Alloc_count(alloc);
407 atp = get_Alloc_type(alloc);
410 if (is_SymConst(size) && get_SymConst_kind(size) == symconst_type_size) {
411 /* if the size is a type size and the types matched */
412 assert(atp == get_SymConst_type(size));
414 } else if (is_Const(size)) {
415 ir_tarval *tv = get_Const_tarval(size);
417 if (tv != tarval_bad && tarval_is_long(tv) &&
418 get_type_state(atp) == layout_fixed &&
419 (unsigned)get_tarval_long(tv) == get_type_size_bytes(atp)) {
420 /* a already lowered type size */
425 if (tp && tp != firm_unknown_type) {
426 /* we could determine the type, so we could place it on the frame */
427 dbg = get_irn_dbg_info(alloc);
428 blk = get_nodes_block(alloc);
430 DBG((dbgHandle, LEVEL_DEFAULT, "%+F allocation of %+F type %+F placed on frame\n", irg, alloc, tp));
432 snprintf(name, sizeof(name), "%s_NE_%u", get_entity_name(get_irg_entity(irg)), nr++);
433 name[sizeof(name) - 1] = '\0';
434 ent = new_d_entity(ftp, new_id_from_str(name), get_Alloc_type(alloc), dbg);
436 sel = new_rd_simpleSel(dbg, get_nodes_block(alloc), get_irg_no_mem(irg), get_irg_frame(irg), ent);
437 mem = get_Alloc_mem(alloc);
439 turn_into_tuple(alloc, pn_Alloc_max);
440 set_Tuple_pred(alloc, pn_Alloc_M, mem);
441 set_Tuple_pred(alloc, pn_Alloc_X_regular, new_r_Jmp(blk));
442 set_Tuple_pred(alloc, pn_Alloc_X_except, new_r_Bad(irg));
443 set_Tuple_pred(alloc, pn_Alloc_res, sel);
449 * We could not determine the type or it is variable size.
450 * At least, we could place it on the stack
452 DBG((dbgHandle, LEVEL_DEFAULT, "%+F allocation of %+F type %+F placed on stack\n", irg, alloc));
453 set_Alloc_where(alloc, stack_alloc);
459 /* if allocs were removed somehow */
460 if (env->nr_removed | env->nr_deads) {
461 set_irg_outs_inconsistent(irg);
464 /* exception control flow might have been changed */
465 set_irg_doms_inconsistent(irg);
471 * Do the necessary graph transformations to transform
474 static void transform_alloc_calls(ir_graph *irg, walk_env_t *env)
476 ir_node *call, *next, *mem, *blk;
479 /* kill all dead allocs */
480 for (call = env->dead_allocs; call; call = next) {
481 next = (ir_node*)get_irn_link(call);
483 DBG((dbgHandle, LEVEL_1, "%+F allocation of %+F unused, deleted.\n", irg, call));
485 mem = get_Call_mem(call);
486 blk = get_nodes_block(call);
487 turn_into_tuple(call, pn_Call_max);
488 set_Tuple_pred(call, pn_Call_M, mem);
489 set_Tuple_pred(call, pn_Call_X_regular, new_r_Jmp(blk));
490 set_Tuple_pred(call, pn_Call_X_except, new_r_Bad(irg));
491 set_Tuple_pred(call, pn_Call_T_result, new_r_Bad(irg));
496 /* convert all non-escaped heap allocs into frame variables */
497 ftp = get_irg_frame_type(irg);
498 for (call = env->found_allocs; call; call = next) {
499 next = (ir_node*)get_irn_link(call);
504 /* Do simple and fast escape analysis for one graph. */
505 void escape_enalysis_irg(ir_graph *irg, check_alloc_entity_func callback)
509 if (get_irg_callee_info_state(irg) != irg_callee_info_consistent) {
510 /* no way yet to calculate this for one irg */
511 assert(! "need callee info");
515 if (get_irg_outs_state(irg) != outs_consistent)
516 compute_irg_outs(irg);
518 env.found_allocs = NULL;
519 env.dead_allocs = NULL;
520 env.callback = callback;
526 /* search for Calls */
527 irg_walk_graph(irg, NULL, find_allocation_calls, &env);
528 transform_alloc_calls(irg, &env);
530 /* search for Alloc nodes */
531 irg_walk_graph(irg, NULL, find_allocations, &env);
532 transform_allocs(irg, &env);
536 /* Do simple and fast escape analysis for all graphs. */
537 void escape_analysis(int run_scalar_replace, check_alloc_entity_func callback)
541 walk_env_t *env, *elist;
542 (void) run_scalar_replace;
544 if (get_irp_callee_info_state() != irg_callee_info_consistent) {
545 assert(! "need callee info");
549 FIRM_DBG_REGISTER(dbgHandle, "firm.opt.escape_ana");
552 * We treat memory for speed: we first collect all info in a
553 * list of environments, than do the transformation.
554 * Doing it this way, no analysis info gets invalid while we run
560 env = OALLOC(&obst, walk_env_t);
561 env->found_allocs = NULL;
562 env->dead_allocs = NULL;
563 env->callback = callback;
565 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
566 ir_graph *irg = get_irp_irg(i);
568 assure_irg_outs(irg);
571 /* search for Calls */
572 irg_walk_graph(irg, NULL, find_allocation_calls, env);
574 /* search for Alloc nodes */
575 irg_walk_graph(irg, NULL, find_allocations, env);
578 if (env->found_allocs || env->dead_allocs) {
586 env = OALLOC(&obst, walk_env_t);
587 env->found_allocs = NULL;
588 env->dead_allocs = NULL;
589 env->callback = callback;
594 for (env = elist; env; env = env->next) {
595 transform_alloc_calls(env->irg, env);
598 for (env = elist; env; env = env->next) {
599 transform_allocs(env->irg, env);
603 obstack_free(&obst, NULL);