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 * @brief Optimization of function calls.
23 * @author Michael Beck
31 #include "irgraph_t.h"
34 #include "dbginfo_t.h"
38 #include "iredges_t.h"
40 #include "iroptimize.h"
41 #include "analyze_irg_args.h"
43 #include "raw_bitset.h"
46 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
49 * The walker environment for updating function calls.
51 typedef struct env_t {
52 size_t n_calls_SymConst;
54 ir_node *float_const_call_list; /**< The list of all floating const function calls that will be changed. */
55 ir_node *nonfloat_const_call_list; /**< The list of all non-floating const function calls that will be changed. */
56 ir_node *pure_call_list; /**< The list of all pure function calls that will be changed. */
57 ir_node *nothrow_call_list; /**< The list of all nothrow function calls that will be changed. */
58 ir_node *proj_list; /**< The list of all potential Proj nodes that must be fixed. */
61 /** Ready IRG's are marked in the ready set. */
62 static unsigned *ready_set;
64 /** IRG's that are in progress are marked here. */
65 static unsigned *busy_set;
68 * We misuse the mtp_property_inherited flag as temporary here.
69 * The is ok, as we cannot set or get it anyway using the
70 * get_addtional_properties API.
72 #define mtp_temporary mtp_property_inherited
75 * Walker: Collect all calls to const and pure functions
76 * to lists. Collect all Proj(Call) nodes into a Proj list.
78 static void collect_const_and_pure_calls(ir_node *node, void *env)
80 env_t *ctx = (env_t*)env;
84 unsigned and_prop, or_prop, prop;
89 /* set the link to NULL for all non-const/pure calls */
90 set_irn_link(call, NULL);
91 ptr = get_Call_ptr(call);
93 ent = get_Global_entity(ptr);
95 prop = get_entity_additional_properties(ent);
96 if ((prop & (mtp_property_const|mtp_property_pure)) == 0)
98 ++ctx->n_calls_SymConst;
99 } else if (get_opt_closed_world() &&
101 get_irg_callee_info_state(get_irn_irg(node)) == irg_callee_info_consistent) {
102 /* If all possible callees are const functions, we can remove the memory edge. */
103 size_t i, n_callees = get_Call_n_callees(call);
104 if (n_callees == 0) {
105 /* This is kind of strange: dying code or a Call that will raise an exception
106 when executed as there is no implementation to call. So better not
111 /* note that const function are a subset of pure ones */
112 and_prop = mtp_property_const | mtp_property_pure;
114 for (i = 0; i < n_callees; ++i) {
115 ent = get_Call_callee(call, i);
116 if (ent == unknown_entity) {
117 /* we don't know which entity is called here */
120 prop = get_entity_additional_properties(ent);
123 if (and_prop == mtp_no_property)
126 prop = and_prop | (or_prop & mtp_property_has_loop);
131 /* ok, if we get here we found a call to a const or a pure function */
132 if (prop & mtp_property_pure) {
133 set_irn_link(call, ctx->pure_call_list);
134 ctx->pure_call_list = call;
136 if (prop & mtp_property_has_loop) {
137 set_irn_link(call, ctx->nonfloat_const_call_list);
138 ctx->nonfloat_const_call_list = call;
140 set_irn_link(call, ctx->float_const_call_list);
141 ctx->float_const_call_list = call;
144 } else if (is_Proj(node)) {
146 * Collect all memory and exception Proj's from
149 call = get_Proj_pred(node);
153 /* collect the Proj's in the Proj list */
154 switch (get_Proj_proj(node)) {
156 case pn_Call_X_except:
157 case pn_Call_X_regular:
158 set_irn_link(node, ctx->proj_list);
159 ctx->proj_list = node;
165 } /* collect_const_and_pure_calls */
168 * Fix the list of collected Calls.
170 * @param irg the graph that contained calls to pure functions
173 static void fix_const_call_lists(ir_graph *irg, env_t *ctx)
175 ir_node *call, *next, *mem, *proj;
178 /* First step: fix all calls by removing their memory input and let
180 * The original memory input is preserved in their link fields. */
181 for (call = ctx->float_const_call_list; call != NULL; call = next) {
182 next = (ir_node*)get_irn_link(call);
183 mem = get_Call_mem(call);
185 set_irn_link(call, mem);
186 set_Call_mem(call, get_irg_no_mem(irg));
189 * Unfortunately we cannot simply set the node to 'float'.
190 * There is a reason for that:
192 * - The call might be inside a loop/if that is NOT entered
193 * and calls a endless function. Setting the call to float
194 * would allow to move it out from the loop/if causing this
195 * function be called even if the loop/if is not entered ...
197 * This could be fixed using post-dominators for calls and Pin nodes
198 * but need some more analyzes to ensure that a call that potential
199 * never returns is not executed before some code that generates
200 * observable states...
203 /* finally, this call can float */
204 set_irn_pinned(call, op_pin_state_floats);
205 hook_func_call(irg, call);
208 /* Last step: fix all Proj's */
209 for (proj = ctx->proj_list; proj != NULL; proj = next) {
210 next = (ir_node*)get_irn_link(proj);
211 call = get_Proj_pred(proj);
212 mem = (ir_node*)get_irn_link(call);
214 /* beware of calls in the pure call list */
215 if (!mem || is_Call(mem))
217 assert(get_irn_mode(mem) == mode_M);
219 switch (get_Proj_proj(proj)) {
221 /* in dead code there might be cycles where proj == mem */
226 case pn_Call_X_except:
228 exchange(proj, new_r_Bad(irg, mode_X));
230 case pn_Call_X_regular: {
231 ir_node *block = get_nodes_block(call);
233 exchange(proj, new_r_Jmp(block));
241 /* changes were done ... */
242 set_irg_loopinfo_state(irg, loopinfo_cf_inconsistent);
245 /* ... including exception edges */
246 set_irg_doms_inconsistent(irg);
248 } /* fix_const_call_list */
251 * Walker: Collect all calls to nothrow functions
252 * to lists. Collect all Proj(Call) nodes into a Proj list.
254 static void collect_nothrow_calls(ir_node *node, void *env)
256 env_t *ctx = (env_t*)env;
264 /* set the link to NULL for all non-const/pure calls */
265 set_irn_link(call, NULL);
266 ptr = get_Call_ptr(call);
267 if (is_Global(ptr)) {
268 ent = get_Global_entity(ptr);
270 prop = get_entity_additional_properties(ent);
271 if ((prop & mtp_property_nothrow) == 0)
273 ++ctx->n_calls_SymConst;
274 } else if (get_opt_closed_world() &&
276 get_irg_callee_info_state(get_irn_irg(node)) == irg_callee_info_consistent) {
277 /* If all possible callees are nothrow functions, we can remove the exception edge. */
278 size_t i, n_callees = get_Call_n_callees(call);
279 if (n_callees == 0) {
280 /* This is kind of strange: dying code or a Call that will raise an exception
281 when executed as there is no implementation to call. So better not
286 /* note that const function are a subset of pure ones */
287 prop = mtp_property_nothrow;
288 for (i = 0; i < n_callees; ++i) {
289 ent = get_Call_callee(call, i);
290 if (ent == unknown_entity) {
291 /* we don't know which entity is called here */
294 prop &= get_entity_additional_properties(ent);
295 if (prop == mtp_no_property)
302 /* ok, if we get here we found a call to a nothrow function */
303 set_irn_link(call, ctx->nothrow_call_list);
304 ctx->nothrow_call_list = call;
305 } else if (is_Proj(node)) {
307 * Collect all memory and exception Proj's from
310 call = get_Proj_pred(node);
314 /* collect the Proj's in the Proj list */
315 switch (get_Proj_proj(node)) {
317 case pn_Call_X_except:
318 case pn_Call_X_regular:
319 set_irn_link(node, ctx->proj_list);
320 ctx->proj_list = node;
326 } /* collect_nothrow_calls */
329 * Fix the list of collected nothrow Calls.
331 * @param irg the graph that contained calls to pure functions
332 * @param call_list the list of all call sites of const functions
333 * @param proj_list the list of all memory/exception Proj's of this call sites
335 static void fix_nothrow_call_list(ir_graph *irg, ir_node *call_list, ir_node *proj_list)
337 ir_node *call, *next, *proj;
340 /* First step: go through the list of calls and mark them. */
341 for (call = call_list; call; call = next) {
342 next = (ir_node*)get_irn_link(call);
344 /* current_ir_graph is in memory anyway, so it's a good marker */
345 set_irn_link(call, ¤t_ir_graph);
346 hook_func_call(irg, call);
349 /* Second step: Remove all exception Proj's */
350 for (proj = proj_list; proj; proj = next) {
351 next = (ir_node*)get_irn_link(proj);
352 call = get_Proj_pred(proj);
354 /* handle only marked calls */
355 if (get_irn_link(call) != ¤t_ir_graph)
358 /* kill any exception flow */
359 switch (get_Proj_proj(proj)) {
360 case pn_Call_X_except:
362 exchange(proj, new_r_Bad(irg, mode_X));
364 case pn_Call_X_regular: {
365 ir_node *block = get_nodes_block(call);
367 exchange(proj, new_r_Jmp(block));
375 /* changes were done ... */
376 set_irg_loopinfo_state(irg, loopinfo_cf_inconsistent);
379 /* ... including exception edges */
380 set_irg_doms_inconsistent(irg);
382 } /* fix_nothrow_call_list */
385 #define SET_IRG_READY(irg) rbitset_set(ready_set, get_irg_idx(irg))
386 #define IS_IRG_READY(irg) rbitset_is_set(ready_set, get_irg_idx(irg))
387 #define SET_IRG_BUSY(irg) rbitset_set(busy_set, get_irg_idx(irg))
388 #define CLEAR_IRG_BUSY(irg) rbitset_clear(busy_set, get_irg_idx(irg))
389 #define IS_IRG_BUSY(irg) rbitset_is_set(busy_set, get_irg_idx(irg))
392 static mtp_additional_properties check_const_or_pure_function(ir_graph *irg, int top);
395 * Calculate the bigger property of two. Handle the temporary flag right.
397 static mtp_additional_properties max_property(mtp_additional_properties a,
398 mtp_additional_properties b)
400 mtp_additional_properties r;
401 mtp_additional_properties t = (a | b) & mtp_temporary;
405 if (a == mtp_no_property || b == mtp_no_property)
406 return mtp_no_property;
412 * Follow the memory chain starting at node and determine
415 * @return mtp_property_const if only calls of const functions are detected
416 * mtp_property_pure if only Loads and const/pure calls detected
417 * mtp_no_property else
419 static mtp_additional_properties follow_mem_(ir_node *node)
421 mtp_additional_properties mode = mtp_property_const;
422 mtp_additional_properties m;
427 if (mode == mtp_no_property)
428 return mtp_no_property;
430 if (irn_visited_else_mark(node))
433 switch (get_irn_opcode(node)) {
435 node = get_Proj_pred(node);
444 /* do a dfs search */
445 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
446 m = follow_mem_(get_irn_n(node, i));
447 mode = max_property(mode, m);
448 if (mode == mtp_no_property)
449 return mtp_no_property;
454 /* Beware volatile Loads are NOT allowed in pure functions. */
455 if (get_Load_volatility(node) == volatility_is_volatile)
456 return mtp_no_property;
457 mode = max_property(mode, mtp_property_pure);
458 node = get_Load_mem(node);
462 /* A call is only tolerable if its either constant or pure. */
463 ptr = get_Call_ptr(node);
464 if (is_SymConst_addr_ent(ptr)) {
465 ir_entity *ent = get_SymConst_entity(ptr);
466 ir_graph *irg = get_entity_irg(ent);
469 m = get_entity_additional_properties(ent) & (mtp_property_const|mtp_property_pure);
470 mode = max_property(mode, m);
472 /* we have a graph, analyze it. */
473 m = check_const_or_pure_function(irg, /*top=*/0);
474 mode = max_property(mode, m);
477 return mtp_no_property;
478 node = get_Call_mem(node);
482 return mtp_no_property;
488 * Follow the memory chain starting at node and determine
491 * @return mtp_property_const if only calls of const functions are detected
492 * mtp_property_pure if only Loads and const/pure calls detected
493 * mtp_no_property else
495 static mtp_additional_properties follow_mem(ir_node *node, mtp_additional_properties mode)
497 mtp_additional_properties m = follow_mem_(node);
498 return max_property(mode, m);
502 * Check if a graph represents a const or a pure function.
504 * @param irg the graph to check
505 * @param top if set, this is the top call
507 static mtp_additional_properties check_const_or_pure_function(ir_graph *irg, int top)
509 ir_node *end, *endbl;
511 mtp_additional_properties prop = get_irg_additional_properties(irg);
513 if (prop & mtp_property_const) {
514 /* already marked as a const function */
515 return mtp_property_const;
517 if (prop & mtp_property_pure) {
518 /* already marked as a pure function */
519 return mtp_property_pure;
522 if (IS_IRG_READY(irg)) {
523 /* already checked */
524 return mtp_no_property;
526 if (IS_IRG_BUSY(irg)) {
527 /* We are still evaluate this method.
528 * The function (indirectly) calls itself and thus may not terminate.
530 return mtp_no_property;
534 end = get_irg_end(irg);
535 endbl = get_nodes_block(end);
536 prop = mtp_property_const;
538 ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
539 inc_irg_visited(irg);
540 /* mark the initial mem: recursion of follow_mem() stops here */
541 mark_irn_visited(get_irg_initial_mem(irg));
543 /* visit every Return */
544 for (j = get_Block_n_cfgpreds(endbl) - 1; j >= 0; --j) {
545 ir_node *node = get_Block_cfgpred(endbl, j);
546 unsigned code = get_irn_opcode(node);
549 /* Bad nodes usually do NOT produce anything, so it's ok */
553 if (code == iro_Return) {
554 mem = get_Return_mem(node);
556 /* Bad nodes usually do NOT produce anything, so it's ok */
560 if (mem != get_irg_initial_mem(irg))
561 prop = max_property(prop, follow_mem(mem, prop));
563 /* Exception found. Cannot be const or pure. */
564 prop = mtp_no_property;
567 if (prop == mtp_no_property)
571 if (prop != mtp_no_property) {
572 /* check, if a keep-alive exists */
573 for (j = get_End_n_keepalives(end) - 1; j >= 0; --j) {
574 ir_node *kept = get_End_keepalive(end, j);
576 if (is_Block(kept)) {
577 prop = mtp_no_property;
581 if (mode_M != get_irn_mode(kept))
584 prop = max_property(prop, follow_mem(kept, prop));
585 if (prop == mtp_no_property)
591 /* Set the property only if we are at top-level. */
592 if (prop != mtp_no_property) {
593 add_irg_additional_properties(irg, prop);
598 ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
600 } /* check_const_or_pure_function */
603 * Handle calls to const functions.
607 static void handle_const_Calls(env_t *ctx)
611 ctx->n_calls_SymConst = 0;
612 ctx->n_calls_Sel = 0;
614 /* all calls of const functions can be transformed */
615 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
616 ir_graph *irg = get_irp_irg(i);
618 ctx->float_const_call_list = NULL;
619 ctx->nonfloat_const_call_list = NULL;
620 ctx->pure_call_list = NULL;
621 ctx->proj_list = NULL;
623 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
624 irg_walk_graph(irg, NULL, collect_const_and_pure_calls, ctx);
626 if (ctx->float_const_call_list != NULL)
627 fix_const_call_lists(irg, ctx);
628 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
630 } /* handle_const_Calls */
633 * Handle calls to nothrow functions.
637 static void handle_nothrow_Calls(env_t *ctx)
641 ctx->n_calls_SymConst = 0;
642 ctx->n_calls_Sel = 0;
644 /* all calls of const functions can be transformed */
645 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
646 ir_graph *irg = get_irp_irg(i);
648 ctx->nothrow_call_list = NULL;
649 ctx->proj_list = NULL;
651 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
652 irg_walk_graph(irg, NULL, collect_nothrow_calls, ctx);
654 if (ctx->nothrow_call_list)
655 fix_nothrow_call_list(irg, ctx->nothrow_call_list, ctx->proj_list);
656 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
661 * Check, whether a given node represents a return value of
662 * a malloc like function (ie, new heap allocated memory).
664 * @param node the node to check
666 static int is_malloc_call_result(const ir_node *node)
668 if (is_Alloc(node) && get_Alloc_where(node) == heap_alloc) {
669 /* Firm style high-level allocation */
672 /* TODO: check mtp_malloc */
677 * Update a property depending on a call property.
679 static mtp_additional_properties update_property(mtp_additional_properties orig_prop, mtp_additional_properties call_prop)
681 mtp_additional_properties t = (orig_prop | call_prop) & mtp_temporary;
682 mtp_additional_properties r = orig_prop & call_prop;
687 * Check if a node is stored.
689 static int is_stored(const ir_node *n)
691 const ir_edge_t *edge;
694 foreach_out_edge(n, edge) {
695 const ir_node *succ = get_edge_src_irn(edge);
697 switch (get_irn_opcode(succ)) {
704 if (get_Store_value(succ) == n)
706 /* ok if its only the address input */
715 ptr = get_Call_ptr(succ);
716 if (is_Global(ptr)) {
717 ir_entity *ent = get_Global_entity(ptr);
720 /* we know the called entity */
721 for (i = get_Call_n_params(succ); i > 0;) {
722 if (get_Call_param(succ, --i) == n) {
723 /* n is the i'th param of the call */
724 if (get_method_param_access(ent, i) & ptr_access_store) {
725 /* n is store in ent */
731 /* unknown call address */
736 /* bad, potential alias */
744 * Check that the return value of an irg is not stored anywhere.
746 * return ~mtp_property_malloc if return values are stored, ~0 else
748 static mtp_additional_properties check_stored_result(ir_graph *irg)
750 ir_node *end_blk = get_irg_end_block(irg);
752 mtp_additional_properties res = ~mtp_no_property;
753 int old_edges = edges_assure_kind(irg, EDGE_KIND_NORMAL);
755 for (i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
756 ir_node *pred = get_Block_cfgpred(end_blk, i);
759 if (! is_Return(pred))
761 for (j = get_Return_n_ress(pred); j > 0;) {
762 const ir_node *irn = get_Return_res(pred, --j);
764 if (is_stored(irn)) {
765 /* bad, might create an alias */
766 res = ~mtp_property_malloc;
773 edges_deactivate_kind(irg, EDGE_KIND_NORMAL);
778 * Check if a graph represents a nothrow or a malloc function.
780 * @param irg the graph to check
781 * @param top if set, this is the top call
783 static mtp_additional_properties check_nothrow_or_malloc(ir_graph *irg, int top)
785 mtp_additional_properties curr_prop = mtp_property_malloc | mtp_property_nothrow;
786 ir_node *end_blk = get_irg_end_block(irg);
791 if (IS_IRG_READY(irg)) {
792 /* already checked */
793 return get_irg_additional_properties(irg);
795 if (IS_IRG_BUSY(irg)) {
796 /* we are still evaluate this method. Be optimistic,
797 return the best possible so far but mark the result as temporary. */
798 return mtp_temporary | mtp_property_malloc | mtp_property_nothrow;
802 ent = get_irg_entity(irg);
803 mtp = get_entity_type(ent);
805 if (get_method_n_ress(mtp) <= 0)
806 curr_prop &= ~mtp_property_malloc;
808 for (i = get_Block_n_cfgpreds(end_blk) - 1; i >= 0; --i) {
809 ir_node *pred = get_Block_cfgpred(end_blk, i);
811 if (is_Return(pred)) {
812 if (curr_prop & mtp_property_malloc) {
815 /* check, if malloc is called here */
816 for (j = get_Return_n_ress(pred); j > 0;) {
817 ir_node *res = get_Return_res(pred, --j);
819 /* skip Confirms and Casts */
820 res = skip_HighLevel_ops(res);
823 res = get_Proj_pred(res);
824 if (is_malloc_call_result(res)) {
825 /* ok, this is a malloc */
826 } else if (is_Call(res)) {
827 ir_node *ptr = get_Call_ptr(res);
829 if (is_Global(ptr)) {
831 ir_entity *ent = get_Global_entity(ptr);
832 ir_graph *callee = get_entity_irg(ent);
835 /* A self-recursive call. The property did not depend on this call. */
836 } else if (callee != NULL) {
837 mtp_additional_properties prop = check_nothrow_or_malloc(callee, /*top=*/0);
838 curr_prop = update_property(curr_prop, prop);
840 curr_prop = update_property(curr_prop, get_entity_additional_properties(ent));
842 } else if (get_opt_closed_world() &&
844 get_irg_callee_info_state(irg) == irg_callee_info_consistent) {
845 /* check if all possible callees are malloc functions. */
846 size_t i, n_callees = get_Call_n_callees(res);
847 if (n_callees == 0) {
848 /* This is kind of strange: dying code or a Call that will raise an exception
849 when executed as there is no implementation to call. So better not
851 curr_prop &= ~mtp_property_malloc;
855 for (i = 0; i < n_callees; ++i) {
856 ir_entity *ent = get_Call_callee(res, i);
857 if (ent == unknown_entity) {
858 /* we don't know which entity is called here */
859 curr_prop &= ~mtp_property_malloc;
862 if ((get_entity_additional_properties(ent) & mtp_property_malloc) == 0) {
863 curr_prop &= ~mtp_property_malloc;
867 /* if we pass the for cycle, malloc is still ok */
870 curr_prop &= ~mtp_property_malloc;
873 /* unknown return value */
874 curr_prop &= ~mtp_property_malloc;
878 } else if (curr_prop & mtp_property_nothrow) {
879 /* exception flow detected */
880 pred = skip_Proj(pred);
883 ir_node *ptr = get_Call_ptr(pred);
885 if (is_Global(ptr)) {
887 ir_entity *ent = get_Global_entity(ptr);
888 ir_graph *callee = get_entity_irg(ent);
891 /* A self-recursive call. The property did not depend on this call. */
892 } else if (callee != NULL) {
893 /* Note: we check here for nothrow only, so do NOT reset the malloc property */
894 mtp_additional_properties prop = check_nothrow_or_malloc(callee, /*top=*/0) | mtp_property_malloc;
895 curr_prop = update_property(curr_prop, prop);
897 if ((get_entity_additional_properties(ent) & mtp_property_nothrow) == 0)
898 curr_prop &= ~mtp_property_nothrow;
900 } else if (get_opt_closed_world() &&
902 get_irg_callee_info_state(irg) == irg_callee_info_consistent) {
903 /* check if all possible callees are nothrow functions. */
904 size_t i, n_callees = get_Call_n_callees(pred);
905 if (n_callees == 0) {
906 /* This is kind of strange: dying code or a Call that will raise an exception
907 when executed as there is no implementation to call. So better not
909 curr_prop &= ~mtp_property_nothrow;
913 for (i = 0; i < n_callees; ++i) {
914 ir_entity *ent = get_Call_callee(pred, i);
915 if (ent == unknown_entity) {
916 /* we don't know which entity is called here */
917 curr_prop &= ~mtp_property_nothrow;
920 if ((get_entity_additional_properties(ent) & mtp_property_nothrow) == 0) {
921 curr_prop &= ~mtp_property_nothrow;
925 /* if we pass the for cycle, nothrow is still ok */
928 curr_prop &= ~mtp_property_nothrow;
931 /* real exception flow possible. */
932 curr_prop &= ~mtp_property_nothrow;
935 if ((curr_prop & ~mtp_temporary) == mtp_no_property) {
936 /* no need to search further */
941 if (curr_prop & mtp_property_malloc) {
943 * Note that the malloc property means not only return newly allocated
944 * memory, but also that this memory is ALIAS FREE.
945 * To ensure that, we do NOT allow that the returned memory is somewhere
948 curr_prop &= check_stored_result(irg);
951 if (curr_prop != mtp_no_property) {
952 if (top || (curr_prop & mtp_temporary) == 0) {
953 /* We use the temporary flag here to mark an optimistic result.
954 Set the property only if we are sure that it does NOT base on
955 temporary results OR if we are at top-level. */
956 add_irg_additional_properties(irg, curr_prop & ~mtp_temporary);
964 } /* check_nothrow_or_malloc */
967 * When a function was detected as "const", it might be moved out of loops.
968 * This might be dangerous if the graph can contain endless loops.
970 static void check_for_possible_endless_loops(ir_graph *irg)
975 root_loop = get_irg_loop(irg);
976 if (root_loop->flags & loop_outer_loop)
977 add_irg_additional_properties(irg, mtp_property_has_loop);
981 * optimize function calls by handling const functions
983 void optimize_funccalls(void)
988 size_t num_const = 0;
990 size_t num_nothrow = 0;
991 size_t num_malloc = 0;
993 /* prepare: mark all graphs as not analyzed */
994 last_idx = get_irp_last_idx();
995 ready_set = rbitset_malloc(last_idx);
996 busy_set = rbitset_malloc(last_idx);
998 /* first step: detect, which functions are nothrow or malloc */
999 DB((dbg, LEVEL_2, "Detecting nothrow and malloc properties ...\n"));
1000 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
1001 ir_graph *irg = get_irp_irg(i);
1002 unsigned prop = check_nothrow_or_malloc(irg, /*top=*/1);
1004 if (prop & mtp_property_nothrow) {
1006 DB((dbg, LEVEL_2, "%+F has the nothrow property\n", irg));
1007 } else if (prop & mtp_property_malloc) {
1009 DB((dbg, LEVEL_2, "%+F has the malloc property\n", irg));
1013 /* second step: remove exception edges: this must be done before the
1014 detection of const and pure functions take place. */
1015 handle_nothrow_Calls(&ctx);
1016 DB((dbg, LEVEL_1, "Detected %zu nothrow graphs, %zu malloc graphs.\n", num_nothrow, num_malloc));
1017 DB((dbg, LEVEL_1, "Optimizes %zu(SymConst) + %zu(Sel) calls to nothrow functions.\n",
1018 ctx.n_calls_SymConst, ctx.n_calls_Sel));
1020 rbitset_clear_all(ready_set, last_idx);
1021 rbitset_clear_all(busy_set, last_idx);
1023 /* third step: detect, which functions are const or pure */
1024 DB((dbg, LEVEL_2, "Detecting const and pure properties ...\n"));
1025 for (i = 0, n = get_irp_n_irgs(); i < n; ++i) {
1026 ir_graph *irg = get_irp_irg(i);
1027 unsigned prop = check_const_or_pure_function(irg, /*top=*/1);
1029 if (prop & mtp_property_const) {
1031 DB((dbg, LEVEL_2, "%+F has the const property\n", irg));
1032 check_for_possible_endless_loops(irg);
1033 } else if (prop & mtp_property_pure) {
1035 DB((dbg, LEVEL_2, "%+F has the pure property\n", irg));
1039 handle_const_Calls(&ctx);
1040 DB((dbg, LEVEL_1, "Detected %zu const graphs, %zu pure graphs.\n", num_const, num_pure));
1041 DB((dbg, LEVEL_1, "Optimizes %u(SymConst) + %u(Sel) calls to const functions.\n",
1042 ctx.n_calls_SymConst, ctx.n_calls_Sel));
1048 /* initialize the funccall optimization */
1049 void firm_init_funccalls(void)
1051 FIRM_DBG_REGISTER(dbg, "firm.opt.funccalls");
1054 /* Creates an ir_prog pass for optimize_funccalls. */
1055 ir_prog_pass_t *optimize_funccalls_pass(const char *name)
1057 return def_prog_pass(name ? name : "funccall", optimize_funccalls);