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
34 #include "irgraph_t.h"
42 /* Note: ir_node.out_valid and ir_graph.n_outs are only present when DEBUG_libfirm is defined */
43 /* Accesses to out_valid and n_outs are fenced out to avoid breakage
44 when compiling with neither DEBUG_libfirm or NDEBUG defined */
45 #endif /* defined DEBUG_libfirm */
47 /*--------------------------------------------------------------------*/
48 /** Accessing the out datastructures **/
49 /*--------------------------------------------------------------------*/
52 /** Clear the outs of a node */
53 static void reset_outs(ir_node *node, void *unused) {
60 int get_irn_outs_computed(const ir_node *node)
62 return node->out != NULL;
65 /* returns the number of successors of the node: */
66 int get_irn_n_outs(const ir_node *node) {
67 assert(node && node->kind == k_ir_node);
69 /* assert(node->out_valid); */
70 #endif /* defined DEBUG_libfirm */
71 /* we misuse the first for the size info of the out array */
72 return node->out[0].pos;
75 /* Access successor n */
76 ir_node *get_irn_out(const ir_node *def, int pos) {
77 assert(pos >= 0 && pos < get_irn_n_outs(def));
79 /* assert(def->out_valid); */
80 #endif /* defined DEBUG_libfirm */
81 return def->out[pos+1].use;
84 /* Access successor n */
85 ir_node *get_irn_out_ex(const ir_node *def, int pos, int *in_pos) {
86 assert(pos >= 0 && pos < get_irn_n_outs(def));
88 /* assert(def->out_valid); */
89 #endif /* defined DEBUG_libfirm */
90 *in_pos = def->out[pos+1].pos;
91 return def->out[pos+1].use;
94 void set_irn_out(ir_node *def, int pos, ir_node *use, int in_pos) {
96 assert(pos >= 0 && pos < get_irn_n_outs(def));
98 def->out_valid = 1; /* assume that this function is used correctly */
99 #endif /* defined DEBUG_libfirm */
100 def->out[pos+1].use = use;
101 def->out[pos+1].pos = in_pos;
104 /* Return the number of control flow successors, ignore keep-alives. */
105 int get_Block_n_cfg_outs(const ir_node *bl) {
106 int i, n_cfg_outs = 0;
107 assert(bl && is_Block(bl));
109 assert(bl->out_valid);
110 #endif /* defined DEBUG_libfirm */
111 for (i = 1; i <= bl->out[0].pos; ++i) {
112 ir_node *succ = bl->out[i].use;
113 if (get_irn_mode(succ) == mode_X && !is_End(succ))
114 n_cfg_outs += succ->out[0].pos;
119 /* Return the number of control flow successors, honor keep-alives. */
120 int get_Block_n_cfg_outs_ka(const ir_node *bl) {
121 int i, n_cfg_outs = 0;
122 assert(bl && is_Block(bl));
124 assert(bl->out_valid);
125 #endif /* defined DEBUG_libfirm */
126 for (i = 1; i <= bl->out[0].pos; ++i) {
127 ir_node *succ = bl->out[i].use;
128 if (get_irn_mode(succ) == mode_X) {
131 /* ignore End if we are in the Endblock */
132 if (get_nodes_block(succ) == bl)
134 else /* count Keep-alive as one */
137 n_cfg_outs += succ->out[0].pos;
143 /* Access predecessor n, ignore keep-alives. */
144 ir_node *get_Block_cfg_out(const ir_node *bl, int pos) {
146 assert(bl && is_Block(bl));
148 assert(bl->out_valid);
149 #endif /* defined DEBUG_libfirm */
150 for (i = 1; i <= bl->out[0].pos; ++i) {
151 ir_node *succ = bl->out[i].use;
152 if (get_irn_mode(succ) == mode_X && !is_End(succ)) {
153 int n_outs = succ->out[0].pos;
155 return succ->out[pos + 1].use;
163 /* Access predecessor n, honor keep-alives. */
164 ir_node *get_Block_cfg_out_ka(const ir_node *bl, int pos) {
166 assert(bl && is_Block(bl));
168 assert (bl->out_valid);
169 #endif /* defined DEBUG_libfirm */
170 for (i = 1; i <= bl->out[0].pos; ++i) {
171 ir_node *succ = bl->out[i].use;
172 if (get_irn_mode(succ) == mode_X) {
174 ir_node *end_bl = get_nodes_block(succ);
176 /* ignore End if we are in the Endblock */
180 /* handle keep-alive here: return the Endblock instead of the End node */
185 n_outs = succ->out[0].pos;
187 return succ->out[pos + 1].use;
196 static void irg_out_walk_2(ir_node *node, irg_walk_func *pre,
197 irg_walk_func *post, void *env) {
202 assert(get_irn_visited(node) < get_irg_visited(current_ir_graph));
204 set_irn_visited(node, get_irg_visited(current_ir_graph));
206 if (pre) pre(node, env);
208 for (i = 0, n = get_irn_n_outs(node); i < n; ++i) {
209 succ = get_irn_out(node, i);
210 if (get_irn_visited(succ) < get_irg_visited(current_ir_graph))
211 irg_out_walk_2(succ, pre, post, env);
214 if (post) post(node, env);
217 void irg_out_walk(ir_node *node,
218 irg_walk_func *pre, irg_walk_func *post,
221 if (get_irg_outs_state(current_ir_graph) != outs_none) {
222 inc_irg_visited (current_ir_graph);
223 irg_out_walk_2(node, pre, post, env);
227 static void irg_out_block_walk2(ir_node *bl,
228 irg_walk_func *pre, irg_walk_func *post,
232 if (!Block_block_visited(bl)) {
233 mark_Block_block_visited(bl);
238 for (i = 0, n = get_Block_n_cfg_outs(bl); i < n; ++i) {
239 /* find the corresponding predecessor block. */
240 ir_node *pred = get_Block_cfg_out(bl, i);
242 irg_out_block_walk2(pred, pre, post, env);
250 /* Walks only over Block nodes in the graph. Has it's own visited
251 flag, so that it can be interleaved with the other walker. */
252 void irg_out_block_walk(ir_node *node,
253 irg_walk_func *pre, irg_walk_func *post,
256 assert(is_Block(node) || (get_irn_mode(node) == mode_X));
258 inc_irg_block_visited(current_ir_graph);
260 if (get_irn_mode(node) == mode_X) {
263 for (i = 0, n = get_irn_n_outs(node); i < n; ++i) {
264 ir_node *succ = get_irn_out(node, i);
265 if (get_irn_visited(succ) < get_irg_visited(current_ir_graph))
266 irg_out_walk_2(succ, pre, post, env);
270 irg_out_block_walk2(node, pre, post, env);
274 /*--------------------------------------------------------------------*/
275 /** Building and Removing the out datastructure **/
277 /** The outs of a graph are allocated in a single, large array. **/
278 /** This allows to allocate and deallocate the memory for the outs **/
279 /** on demand. The large array is separated into many small ones **/
280 /** for each node. Only a single field to reference the out array **/
281 /** is stored in each node and a field referencing the large out **/
282 /** array in irgraph. The 0 field of each out array contains the **/
283 /** size of this array. This saves memory in the irnodes themselves.**/
284 /** The construction does two passes over the graph. The first pass **/
285 /** counts the overall number of outs and the outs of each node. It **/
286 /** stores the outs of each node in the out reference of the node. **/
287 /** Then the large array is allocated. The second iteration chops **/
288 /** the large array into smaller parts, sets the out edges and **/
289 /** recounts the out edges. **/
290 /** Removes Tuple nodes! **/
291 /*--------------------------------------------------------------------*/
294 /** Returns the amount of out edges for not yet visited successors. */
295 static int _count_outs(ir_node *n) {
296 int start, i, res, irn_arity;
299 n->out = INT_TO_PTR(1); /* Space for array size. */
301 start = is_Block(n) ? 0 : -1;
302 irn_arity = get_irn_arity(n);
303 res = irn_arity - start + 1; /* --1 or --0; 1 for array size. */
305 for (i = start; i < irn_arity; ++i) {
306 /* Optimize Tuples. They annoy if walking the cfg. */
307 ir_node *pred = get_irn_n(n, i);
308 ir_node *skipped_pred = skip_Tuple(pred);
310 if (skipped_pred != pred) {
311 set_irn_n(n, i, skipped_pred);
314 /* count Def-Use edges for predecessors */
315 if (!irn_visited(skipped_pred))
316 res += _count_outs(skipped_pred);
318 /*count my Def-Use edges */
319 skipped_pred->out = INT_TO_PTR(PTR_TO_INT(skipped_pred->out) + 1);
325 /** Returns the amount of out edges for not yet visited successors.
326 * This version handles some special nodes like irg_frame, irg_args etc.
328 static int count_outs(ir_graph *irg) {
332 inc_irg_visited(irg);
333 res = _count_outs(get_irg_end(irg));
335 /* Now handle anchored nodes. We need the out count of those
336 even if they are not visible. */
337 for (i = anchor_last - 1; i >= 0; --i) {
338 n = get_irg_anchor(irg, i);
339 if (!irn_visited_else_mark(n)) {
340 n->out = INT_TO_PTR(1);
348 * Enter memory for the outs to a node.
350 * @param use current node
351 * @param free current free address in the chunk allocated for the outs
353 * @return The next free address
355 static ir_def_use_edge *_set_out_edges(ir_node *use, ir_def_use_edge *free) {
356 int n_outs, start, i, irn_arity, pos;
358 mark_irn_visited(use);
360 /* Allocate my array */
361 n_outs = PTR_TO_INT(use->out);
365 #endif /* defined DEBUG_libfirm */
367 /* We count the successors again, the space will be sufficient.
368 We use this counter to remember the position for the next back
372 start = is_Block(use) ? 0 : -1;
373 irn_arity = get_irn_arity(use);
375 for (i = start; i < irn_arity; ++i) {
376 ir_node *def = get_irn_n(use, i);
379 if (!irn_visited(def))
380 free = _set_out_edges(def, free);
382 /* Remember this Def-Use edge */
383 pos = def->out[0].pos + 1;
384 def->out[pos].use = use;
385 def->out[pos].pos = i;
387 /* increase the number of Def-Use edges so far */
388 def->out[0].pos = pos;
394 * Enter memory for the outs to a node. Handles special nodes
396 * @param irg the graph
397 * @param free current free address in the chunk allocated for the outs
399 * @return The next free address
401 static ir_def_use_edge *set_out_edges(ir_graph *irg, ir_def_use_edge *free) {
405 inc_irg_visited(irg);
406 free = _set_out_edges(get_irg_end(irg), free);
408 /* handle anchored nodes */
409 for (i = anchor_last - 1; i >= 0; --i) {
410 n = get_irg_anchor(irg, i);
411 if (!irn_visited_else_mark(n)) {
412 n_outs = PTR_TO_INT(n->out);
416 #endif /* defined DEBUG_libfirm */
426 * We want that the out of ProjX from Start contains the next block at
427 * position 0, the Start block at position 1. This is necessary for
428 * the out block walker.
430 static inline void fix_start_proj(ir_graph *irg) {
431 ir_node *startbl = get_irg_start_block(irg);
433 if (get_Block_n_cfg_outs(startbl)) {
434 ir_node *proj = get_irg_initial_exec(irg);
436 int block_pos, other_pos;
438 if (get_irn_n_outs(proj) == 2) {
439 if (get_irn_out_ex(proj, 0, &block_pos) == startbl) {
440 irn = get_irn_out_ex(proj, 1, &other_pos);
441 set_irn_out(proj, 0, irn, other_pos);
442 set_irn_out(proj, 1, startbl, block_pos);
445 assert(get_irg_phase_state(irg) == phase_backend);
450 /* compute the outs for a given graph */
451 void compute_irg_outs(ir_graph *irg) {
452 ir_graph *rem = current_ir_graph;
454 ir_def_use_edge *end = NULL; /* Only for debugging */
456 current_ir_graph = irg;
458 /* Update graph state */
459 assert(get_irg_phase_state(current_ir_graph) != phase_building);
461 if (current_ir_graph->outs_state != outs_none)
462 free_irg_outs(current_ir_graph);
464 /* This first iteration counts the overall number of out edges and the
465 number of out edges for each node. */
466 n_out_edges = count_outs(irg);
468 /* allocate memory for all out edges. */
469 irg->outs = XMALLOCNZ(ir_def_use_edge, n_out_edges);
471 irg->n_outs = n_out_edges;
472 #endif /* defined DEBUG_libfirm */
474 /* The second iteration splits the irg->outs array into smaller arrays
475 for each node and writes the back edges into this array. */
476 end = set_out_edges(irg, irg->outs);
478 /* Check how much memory we have used */
479 assert (end == (irg->outs + n_out_edges));
481 /* We want that the out of ProjX from Start contains the next block at
482 position 0, the Start block at position 1. This is necessary for
483 code placement (place_early() ONLY if started GCSE on graphs with dead blocks) */
486 current_ir_graph->outs_state = outs_consistent;
487 current_ir_graph = rem;
490 void assure_irg_outs(ir_graph *irg) {
491 if (get_irg_outs_state(irg) != outs_consistent)
492 compute_irg_outs(irg);
495 void compute_irp_outs(void) {
497 for (i = get_irp_n_irgs() -1; i >= 0; --i)
498 compute_irg_outs(get_irp_irg(i));
501 void free_irp_outs(void) {
503 for (i = get_irp_n_irgs() -1; i >= 0; --i)
504 free_irg_outs(get_irp_irg(i));
508 /*------------------------------------------------------------*
509 * This computes the outedges for in interprocedural graph. *
510 * There is one quirk: *
511 * The number of the outedges for each node is saved in *
512 * the first member of the ir_node** array. Maybe we should *
513 * change this to make it more portable... *
514 *------------------------------------------------------------*/
517 #ifdef INTERPROCEDURAL_VIEW
519 * Inits the number of outedges for each node
522 static void init_count(ir_node * node, void *env) {
524 node->out = (ir_node **) 1; /* 1 for the array size */
529 * Adjusts the out edge count for its predecessors
530 * and adds the current arity to the overall count,
531 * which is saved in "env"
533 static void node_arity_count(ir_node * node, void * env) {
534 int *anz = (int *) env, arity, n_outs, i, start;
537 arity = get_irn_arity(node);
538 start = (is_Block(node)) ? 0 : -1;
540 n_outs = 1 + arity + (-start); // ((is_Block(node)) ? 0 : 1); // Why + 1??
543 for(i = start; i < arity; i++) {
544 succ = get_irn_n(node, i);
545 succ->out = (ir_node **)INT_TO_PTR(PTR_TO_INT(succ->out) + 1);
550 * Inits all nodes for setting the outedges
551 * Returns the overall count of edges
553 int count_ip_outs(void) {
556 cg_walk(init_count, node_arity_count, &res);
561 static int dummy_count = 0, global_count; /* Only for debugging */
564 * For each node: Sets the pointer to array
565 * in which the outedges are written later.
566 * The current array start is transported in env
568 static void set_array_pointer(ir_node *node, void *env) {
570 ir_node ***free = (ir_node ***) env;
572 /* Allocate my array */
573 n_outs = PTR_TO_INT(node->out); /* We wrote the count here in count_ip_outs */
574 dummy_count += n_outs;
575 assert(dummy_count <= global_count && "More outedges than initially counted!");
577 *free = &((*free)[n_outs]);
578 /* We count the successors again, the space will be sufficient.
579 We use this counter to remember the position for the next back
581 node -> out[0] = (ir_node *) 0;
586 * Adds an outedge from the predecessor to the
589 static void set_out_pointer(ir_node * node, void *env) {
590 int i, arity = get_irn_arity(node);
592 int start = (!is_Block(node)) ? -1 : 0;
595 for (i = start; i < arity; ++i) {
596 succ = get_irn_n(node, i);
597 succ->out[get_irn_n_outs(succ)+1] = node;
598 succ->out[0] = INT_TO_PTR(get_irn_n_outs(succ) + 1);
604 * Sets the outedges for all nodes.
606 void set_ip_outs(void) {
607 ir_node **outedge_array = get_irp_ip_outedges();
608 cg_walk(set_array_pointer, set_out_pointer, (void *) &outedge_array);
614 * Counts the outedges, allocates memory to save the
615 * outedges and fills this outedge array in interprocedural
618 void compute_ip_outs(void) {
622 assert(get_irp_ip_view_state() == ip_view_valid &&
623 "Cannot construct outs for invalid ip view.");
625 if (irp->outs_state != outs_none) {
629 global_count = n_out_edges = count_ip_outs();
630 out_edges = XMALLOCNZ(ir_node*, n_out_edges);
631 set_irp_ip_outedges(out_edges);
635 void free_ip_outs(void) {
636 ir_node **out_edges = get_irp_ip_outedges();
637 if (out_edges != NULL) {
639 set_irp_ip_outedges(NULL);
641 irp->outs_state = outs_none;
646 void free_irg_outs(ir_graph *irg) {
647 /* current_ir_graph->outs_state = outs_none; */
648 irg->outs_state = outs_none;
652 memset(irg->outs, 0, irg->n_outs);
653 #endif /* defined DEBUG_libfirm */
658 #endif /* defined DEBUG_libfirm */
662 /* when debugging, *always* reset all nodes' outs! irg->outs might
663 have been lying to us */
664 irg_walk_graph (irg, reset_outs, NULL, NULL);
665 #endif /* defined DEBUG_libfirm */
668 static void check_out_edges(ir_node *irn, void *env) {
672 int last = is_Block(irn) ? 0 : -1;
674 /* check forward: every input must have an out edge */
675 for (i = get_irn_arity(irn) - 1; i >= last; --i) {
676 ir_node *pred = get_irn_n(irn, i);
678 for (j = get_irn_n_outs(pred) - 1; j >= 0; --j) {
679 ir_node *user = get_irn_out_ex(pred, j, &pos);
681 if (user == irn && pos == i) {
686 ir_fprintf(stderr, "Missing out edge from %+F input %d to %+F", irn, i, pred);
691 /* checking backward */
692 for (i = get_irn_n_outs(irn) - 1; i >= 0; --i) {
693 ir_node *user = get_irn_out_ex(irn, i, &pos);
695 if (get_irn_n(user, pos) != irn) {
696 ir_fprintf(stderr, "Spurious out edge from %+F output %d to %+F", irn, i, user);
703 /* verify outs edges. */
704 void verify_outs(ir_graph *irg) {
706 irg_walk_graph(irg, NULL, check_out_edges, &errors);
708 panic("Out edges are corrupt");