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 Compute and access out edges (also called def-use edges).
23 * @author Goetz Lindenmaier, Michael Beck
38 #include "irgraph_t.h"
46 /* Note: ir_node.out_valid and ir_graph.n_outs are only present when DEBUG_libfirm is defined */
47 /* Accesses to out_valid and n_outs are fenced out to avoid breakage
48 when compiling with neither DEBUG_libfirm or NDEBUG defined */
49 #endif /* defined DEBUG_libfirm */
51 /*--------------------------------------------------------------------*/
52 /** Accessing the out datastructures **/
53 /*--------------------------------------------------------------------*/
56 /** Clear the outs of a node */
57 static void reset_outs(ir_node *node, void *unused) {
64 int get_irn_outs_computed(const ir_node *node)
66 return node->out != NULL;
69 /* returns the number of successors of the node: */
70 int get_irn_n_outs(const ir_node *node) {
71 assert(node && node->kind == k_ir_node);
73 /* assert(node->out_valid); */
74 #endif /* defined DEBUG_libfirm */
75 /* we misuse the first for the size info of the out array */
76 return node->out[0].pos;
79 /* Access successor n */
80 ir_node *get_irn_out(const ir_node *def, int pos) {
81 assert(pos >= 0 && pos < get_irn_n_outs(def));
83 /* assert(def->out_valid); */
84 #endif /* defined DEBUG_libfirm */
85 return def->out[pos+1].use;
88 /* Access successor n */
89 ir_node *get_irn_out_ex(const ir_node *def, int pos, int *in_pos) {
90 assert(pos >= 0 && pos < get_irn_n_outs(def));
92 /* assert(def->out_valid); */
93 #endif /* defined DEBUG_libfirm */
94 *in_pos = def->out[pos+1].pos;
95 return def->out[pos+1].use;
98 void set_irn_out(ir_node *def, int pos, ir_node *use, int in_pos) {
100 assert(pos >= 0 && pos < get_irn_n_outs(def));
102 def->out_valid = 1; /* assume that this function is used correctly */
103 #endif /* defined DEBUG_libfirm */
104 def->out[pos+1].use = use;
105 def->out[pos+1].pos = in_pos;
108 /* Return the number of control flow successors, ignore keep-alives. */
109 int get_Block_n_cfg_outs(const ir_node *bl) {
110 int i, n_cfg_outs = 0;
111 assert(bl && is_Block(bl));
113 assert(bl->out_valid);
114 #endif /* defined DEBUG_libfirm */
115 for (i = 1; i <= bl->out[0].pos; ++i) {
116 ir_node *succ = bl->out[i].use;
117 if (get_irn_mode(succ) == mode_X && !is_End(succ))
118 n_cfg_outs += succ->out[0].pos;
123 /* Return the number of control flow successors, honor keep-alives. */
124 int get_Block_n_cfg_outs_ka(const ir_node *bl) {
125 int i, n_cfg_outs = 0;
126 assert(bl && is_Block(bl));
128 assert(bl->out_valid);
129 #endif /* defined DEBUG_libfirm */
130 for (i = 1; i <= bl->out[0].pos; ++i) {
131 ir_node *succ = bl->out[i].use;
132 if (get_irn_mode(succ) == mode_X) {
135 /* ignore End if we are in the Endblock */
136 if (get_nodes_block(succ) == bl)
138 else /* count Keep-alive as one */
141 n_cfg_outs += succ->out[0].pos;
147 /* Access predecessor n, ignore keep-alives. */
148 ir_node *get_Block_cfg_out(const ir_node *bl, int pos) {
150 assert(bl && is_Block(bl));
152 assert(bl->out_valid);
153 #endif /* defined DEBUG_libfirm */
154 for (i = 1; i <= bl->out[0].pos; ++i) {
155 ir_node *succ = bl->out[i].use;
156 if (get_irn_mode(succ) == mode_X && !is_End(succ)) {
157 int n_outs = succ->out[0].pos;
159 return succ->out[pos + 1].use;
167 /* Access predecessor n, honor keep-alives. */
168 ir_node *get_Block_cfg_out_ka(const ir_node *bl, int pos) {
170 assert(bl && is_Block(bl));
172 assert (bl->out_valid);
173 #endif /* defined DEBUG_libfirm */
174 for (i = 1; i <= bl->out[0].pos; ++i) {
175 ir_node *succ = bl->out[i].use;
176 if (get_irn_mode(succ) == mode_X) {
178 ir_node *end_bl = get_nodes_block(succ);
180 /* ignore End if we are in the Endblock */
184 /* handle keep-alive here: return the Endblock instead of the End node */
189 n_outs = succ->out[0].pos;
191 return succ->out[pos + 1].use;
200 static void irg_out_walk_2(ir_node *node, irg_walk_func *pre,
201 irg_walk_func *post, void *env) {
206 assert(get_irn_visited(node) < get_irg_visited(current_ir_graph));
208 set_irn_visited(node, get_irg_visited(current_ir_graph));
210 if (pre) pre(node, env);
212 for (i = 0, n = get_irn_n_outs(node); i < n; ++i) {
213 succ = get_irn_out(node, i);
214 if (get_irn_visited(succ) < get_irg_visited(current_ir_graph))
215 irg_out_walk_2(succ, pre, post, env);
218 if (post) post(node, env);
221 void irg_out_walk(ir_node *node,
222 irg_walk_func *pre, irg_walk_func *post,
225 if (get_irg_outs_state(current_ir_graph) != outs_none) {
226 inc_irg_visited (current_ir_graph);
227 irg_out_walk_2(node, pre, post, env);
231 static void irg_out_block_walk2(ir_node *bl,
232 irg_walk_func *pre, irg_walk_func *post,
236 if (!Block_block_visited(bl)) {
237 mark_Block_block_visited(bl);
242 for (i = 0, n = get_Block_n_cfg_outs(bl); i < n; ++i) {
243 /* find the corresponding predecessor block. */
244 ir_node *pred = get_Block_cfg_out(bl, i);
246 irg_out_block_walk2(pred, pre, post, env);
254 /* Walks only over Block nodes in the graph. Has it's own visited
255 flag, so that it can be interleaved with the other walker. */
256 void irg_out_block_walk(ir_node *node,
257 irg_walk_func *pre, irg_walk_func *post,
260 assert(is_Block(node) || (get_irn_mode(node) == mode_X));
262 inc_irg_block_visited(current_ir_graph);
264 if (get_irn_mode(node) == mode_X) {
267 for (i = 0, n = get_irn_n_outs(node); i < n; ++i) {
268 ir_node *succ = get_irn_out(node, i);
269 if (get_irn_visited(succ) < get_irg_visited(current_ir_graph))
270 irg_out_walk_2(succ, pre, post, env);
274 irg_out_block_walk2(node, pre, post, env);
278 /*--------------------------------------------------------------------*/
279 /** Building and Removing the out datastructure **/
281 /** The outs of a graph are allocated in a single, large array. **/
282 /** This allows to allocate and deallocate the memory for the outs **/
283 /** on demand. The large array is separated into many small ones **/
284 /** for each node. Only a single field to reference the out array **/
285 /** is stored in each node and a field referencing the large out **/
286 /** array in irgraph. The 0 field of each out array contains the **/
287 /** size of this array. This saves memory in the irnodes themselves.**/
288 /** The construction does two passes over the graph. The first pass **/
289 /** counts the overall number of outs and the outs of each node. It **/
290 /** stores the outs of each node in the out reference of the node. **/
291 /** Then the large array is allocated. The second iteration chops **/
292 /** the large array into smaller parts, sets the out edges and **/
293 /** recounts the out edges. **/
294 /** Removes Tuple nodes! **/
295 /*--------------------------------------------------------------------*/
298 /** Returns the amount of out edges for not yet visited successors. */
299 static int _count_outs(ir_node *n) {
300 int start, i, res, irn_arity;
303 n->out = INT_TO_PTR(1); /* Space for array size. */
305 start = is_Block(n) ? 0 : -1;
306 irn_arity = get_irn_arity(n);
307 res = irn_arity - start + 1; /* --1 or --0; 1 for array size. */
309 for (i = start; i < irn_arity; ++i) {
310 /* Optimize Tuples. They annoy if walking the cfg. */
311 ir_node *pred = get_irn_n(n, i);
312 ir_node *skipped_pred = skip_Tuple(pred);
314 if (skipped_pred != pred) {
315 set_irn_n(n, i, skipped_pred);
318 /* count Def-Use edges for predecessors */
319 if (!irn_visited(skipped_pred))
320 res += _count_outs(skipped_pred);
322 /*count my Def-Use edges */
323 skipped_pred->out = INT_TO_PTR(PTR_TO_INT(skipped_pred->out) + 1);
329 /** Returns the amount of out edges for not yet visited successors.
330 * This version handles some special nodes like irg_frame, irg_args etc.
332 static int count_outs(ir_graph *irg) {
336 inc_irg_visited(irg);
337 res = _count_outs(get_irg_end(irg));
339 /* Now handle anchored nodes. We need the out count of those
340 even if they are not visible. */
341 for (i = anchor_last - 1; i >= 0; --i) {
342 n = get_irg_anchor(irg, i);
343 if (!irn_visited_else_mark(n)) {
344 n->out = INT_TO_PTR(1);
352 * Enter memory for the outs to a node.
354 * @param use current node
355 * @param free current free address in the chunk allocated for the outs
357 * @return The next free address
359 static ir_def_use_edge *_set_out_edges(ir_node *use, ir_def_use_edge *free) {
360 int n_outs, start, i, irn_arity, pos;
362 mark_irn_visited(use);
364 /* Allocate my array */
365 n_outs = PTR_TO_INT(use->out);
369 #endif /* defined DEBUG_libfirm */
371 /* We count the successors again, the space will be sufficient.
372 We use this counter to remember the position for the next back
376 start = is_Block(use) ? 0 : -1;
377 irn_arity = get_irn_arity(use);
379 for (i = start; i < irn_arity; ++i) {
380 ir_node *def = get_irn_n(use, i);
383 if (!irn_visited(def))
384 free = _set_out_edges(def, free);
386 /* Remember this Def-Use edge */
387 pos = def->out[0].pos + 1;
388 def->out[pos].use = use;
389 def->out[pos].pos = i;
391 /* increase the number of Def-Use edges so far */
392 def->out[0].pos = pos;
398 * Enter memory for the outs to a node. Handles special nodes
400 * @param irg the graph
401 * @param free current free address in the chunk allocated for the outs
403 * @return The next free address
405 static ir_def_use_edge *set_out_edges(ir_graph *irg, ir_def_use_edge *free) {
409 inc_irg_visited(irg);
410 free = _set_out_edges(get_irg_end(irg), free);
412 /* handle anchored nodes */
413 for (i = anchor_last - 1; i >= 0; --i) {
414 n = get_irg_anchor(irg, i);
415 if (!irn_visited_else_mark(n)) {
416 n_outs = PTR_TO_INT(n->out);
420 #endif /* defined DEBUG_libfirm */
430 * We want that the out of ProjX from Start contains the next block at
431 * position 0, the Start block at position 1. This is necessary for
432 * the out block walker.
434 static INLINE void fix_start_proj(ir_graph *irg) {
435 ir_node *startbl = get_irg_start_block(irg);
437 if (get_Block_n_cfg_outs(startbl)) {
438 ir_node *proj = get_irg_initial_exec(irg);
440 int block_pos, other_pos;
442 if (get_irn_n_outs(proj) == 2) {
443 if (get_irn_out_ex(proj, 0, &block_pos) == startbl) {
444 irn = get_irn_out_ex(proj, 1, &other_pos);
445 set_irn_out(proj, 0, irn, other_pos);
446 set_irn_out(proj, 1, startbl, block_pos);
449 assert(get_irg_phase_state(irg) == phase_backend);
454 /* compute the outs for a given graph */
455 void compute_irg_outs(ir_graph *irg) {
456 ir_graph *rem = current_ir_graph;
458 ir_def_use_edge *end = NULL; /* Only for debugging */
460 current_ir_graph = irg;
462 /* Update graph state */
463 assert(get_irg_phase_state(current_ir_graph) != phase_building);
465 if (current_ir_graph->outs_state != outs_none)
466 free_irg_outs(current_ir_graph);
468 /* This first iteration counts the overall number of out edges and the
469 number of out edges for each node. */
470 n_out_edges = count_outs(irg);
472 /* allocate memory for all out edges. */
473 irg->outs = XMALLOCNZ(ir_def_use_edge, n_out_edges);
475 irg->n_outs = n_out_edges;
476 #endif /* defined DEBUG_libfirm */
478 /* The second iteration splits the irg->outs array into smaller arrays
479 for each node and writes the back edges into this array. */
480 end = set_out_edges(irg, irg->outs);
482 /* Check how much memory we have used */
483 assert (end == (irg->outs + n_out_edges));
485 /* We want that the out of ProjX from Start contains the next block at
486 position 0, the Start block at position 1. This is necessary for
487 code placement (place_early() ONLY if started GCSE on graphs with dead blocks) */
490 current_ir_graph->outs_state = outs_consistent;
491 current_ir_graph = rem;
494 void assure_irg_outs(ir_graph *irg) {
495 if (get_irg_outs_state(irg) != outs_consistent)
496 compute_irg_outs(irg);
499 void compute_irp_outs(void) {
501 for (i = get_irp_n_irgs() -1; i >= 0; --i)
502 compute_irg_outs(get_irp_irg(i));
505 void free_irp_outs(void) {
507 for (i = get_irp_n_irgs() -1; i >= 0; --i)
508 free_irg_outs(get_irp_irg(i));
512 /*------------------------------------------------------------*
513 * This computes the outedges for in interprocedural graph. *
514 * There is one quirk: *
515 * The number of the outedges for each node is saved in *
516 * the first member of the ir_node** array. Maybe we should *
517 * change this to make it more portable... *
518 *------------------------------------------------------------*/
521 #ifdef INTERPROCEDURAL_VIEW
523 * Inits the number of outedges for each node
526 static void init_count(ir_node * node, void *env) {
528 node->out = (ir_node **) 1; /* 1 for the array size */
533 * Adjusts the out edge count for its predecessors
534 * and adds the current arity to the overall count,
535 * which is saved in "env"
537 static void node_arity_count(ir_node * node, void * env) {
538 int *anz = (int *) env, arity, n_outs, i, start;
541 arity = get_irn_arity(node);
542 start = (is_Block(node)) ? 0 : -1;
544 n_outs = 1 + arity + (-start); // ((is_Block(node)) ? 0 : 1); // Why + 1??
547 for(i = start; i < arity; i++) {
548 succ = get_irn_n(node, i);
549 succ->out = (ir_node **)INT_TO_PTR(PTR_TO_INT(succ->out) + 1);
554 * Inits all nodes for setting the outedges
555 * Returns the overall count of edges
557 int count_ip_outs(void) {
560 cg_walk(init_count, node_arity_count, &res);
565 static int dummy_count = 0, global_count; /* Only for debugging */
568 * For each node: Sets the pointer to array
569 * in which the outedges are written later.
570 * The current array start is transported in env
572 static void set_array_pointer(ir_node *node, void *env) {
574 ir_node ***free = (ir_node ***) env;
576 /* Allocate my array */
577 n_outs = PTR_TO_INT(node->out); /* We wrote the count here in count_ip_outs */
578 dummy_count += n_outs;
579 assert(dummy_count <= global_count && "More outedges than initially counted!");
581 *free = &((*free)[n_outs]);
582 /* We count the successors again, the space will be sufficient.
583 We use this counter to remember the position for the next back
585 node -> out[0] = (ir_node *) 0;
590 * Adds an outedge from the predecessor to the
593 static void set_out_pointer(ir_node * node, void *env) {
594 int i, arity = get_irn_arity(node);
596 int start = (!is_Block(node)) ? -1 : 0;
599 for (i = start; i < arity; ++i) {
600 succ = get_irn_n(node, i);
601 succ->out[get_irn_n_outs(succ)+1] = node;
602 succ->out[0] = INT_TO_PTR(get_irn_n_outs(succ) + 1);
608 * Sets the outedges for all nodes.
610 void set_ip_outs(void) {
611 ir_node **outedge_array = get_irp_ip_outedges();
612 cg_walk(set_array_pointer, set_out_pointer, (void *) &outedge_array);
618 * Counts the outedges, allocates memory to save the
619 * outedges and fills this outedge array in interprocedural
622 void compute_ip_outs(void) {
626 assert(get_irp_ip_view_state() == ip_view_valid &&
627 "Cannot construct outs for invalid ip view.");
629 if (irp->outs_state != outs_none) {
633 global_count = n_out_edges = count_ip_outs();
634 out_edges = XMALLOCNZ(ir_node*, n_out_edges);
635 set_irp_ip_outedges(out_edges);
639 void free_ip_outs(void) {
640 ir_node **out_edges = get_irp_ip_outedges();
641 if (out_edges != NULL) {
643 set_irp_ip_outedges(NULL);
645 irp->outs_state = outs_none;
650 void free_irg_outs(ir_graph *irg) {
651 /* current_ir_graph->outs_state = outs_none; */
652 irg->outs_state = outs_none;
656 memset(irg->outs, 0, irg->n_outs);
657 #endif /* defined DEBUG_libfirm */
662 #endif /* defined DEBUG_libfirm */
666 /* when debugging, *always* reset all nodes' outs! irg->outs might
667 have been lying to us */
668 irg_walk_graph (irg, reset_outs, NULL, NULL);
669 #endif /* defined DEBUG_libfirm */
672 static void check_out_edges(ir_node *irn, void *env) {
676 int last = is_Block(irn) ? 0 : -1;
678 /* check forward: every input must have an out edge */
679 for (i = get_irn_arity(irn) - 1; i >= last; --i) {
680 ir_node *pred = get_irn_n(irn, i);
682 for (j = get_irn_n_outs(pred) - 1; j >= 0; --j) {
683 ir_node *user = get_irn_out_ex(pred, j, &pos);
685 if (user == irn && pos == i) {
690 ir_fprintf(stderr, "Missing out edge from %+F input %d to %+F", irn, i, pred);
695 /* checking backward */
696 for (i = get_irn_n_outs(irn) - 1; i >= 0; --i) {
697 ir_node *user = get_irn_out_ex(irn, i, &pos);
699 if (get_irn_n(user, pos) != irn) {
700 ir_fprintf(stderr, "Spurious out edge from %+F output %d to %+F", irn, i, user);
707 /* verify outs edges. */
708 void verify_outs(ir_graph *irg) {
710 irg_walk_graph(irg, NULL, check_out_edges, &errors);
712 panic("Out edges are corrupt");