-/* Copyright (C) 2002 by Universitaet Karlsruhe
-** All rights reserved.
-**
-** Authors: Goetz Lindenmaier
-**
-** irdom.c --- Dominator tree.
-**
-*/
+/*
+ * Project: libFIRM
+ * File name: ir/ana/irdom.c
+ * Purpose: Construct and access dominator tree.
+ * Author: Goetz Lindenmaier
+ * Modified by:
+ * Created: 2.2002
+ * CVS-ID: $Id$
+ * Copyright: (c) 2002-2003 Universität Karlsruhe
+ * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
-/* $Id$ */
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
#include "irouts.h"
+#include "xmalloc.h"
+#include "irgwalk.h"
#include "irdom_t.h"
#include "irgraph_t.h" /* To access state field. */
#include "irnode_t.h"
+#include "ircons_t.h"
-/**********************************************************************/
-/** Accessing the dominator datastructures **/
-/**********************************************************************/
+#define get_dom_info(bl) (&(bl)->attr.block.dom)
-ir_node *get_Block_idom(ir_node *bl) {
- assert(get_irn_op(bl) == op_Block);
- return bl->attr.block.dom.idom;
+
+/*--------------------------------------------------------------------*/
+/** Accessing the dominator data structures **/
+/*--------------------------------------------------------------------*/
+
+ir_node *get_Block_idom(const ir_node *bl) {
+ assert(is_Block(bl));
+ if (get_Block_dom_depth(bl) == -1) {
+ /* This block is not reachable from Start */
+ return new_Bad();
+ }
+ return get_dom_info(bl)->idom;
}
void set_Block_idom(ir_node *bl, ir_node *n) {
+ dom_info *bli = get_dom_info(bl);
+
assert(get_irn_op(bl) == op_Block);
- bl->attr.block.dom.idom = n;
+
+ /* Set the immediate dominator of bl to n */
+ bli->idom = n;
+
+ /*
+ * If we don't set the root of the dominator tree
+ * Append bl to the dominates queue of n.
+ */
+ if(n != NULL) {
+ dom_info *ni = get_dom_info(n);
+
+ bli->next = ni->first;
+ ni->first = bl;
+ }
}
-int get_Block_pre_num(ir_node *bl) {
+int get_Block_pre_num(const ir_node *bl) {
assert(get_irn_op(bl) == op_Block);
return bl->attr.block.dom.pre_num;
}
bl->attr.block.dom.pre_num = num;
}
-int get_Block_dom_depth(ir_node *bl) {
+int get_Block_dom_depth(const ir_node *bl) {
assert(get_irn_op(bl) == op_Block);
return bl->attr.block.dom.dom_depth;
}
bl->attr.block.dom.dom_depth = depth;
}
+unsigned get_Block_dom_tree_pre_num(const ir_node *bl)
+{
+ assert(is_Block(bl));
+ return get_dom_info(bl)->tree_pre_num;
+}
+
+unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl)
+{
+ assert(is_Block(bl));
+ return get_dom_info(bl)->max_subtree_pre_num;
+}
+
+int block_dominates(const ir_node *a, const ir_node *b)
+{
+ const dom_info *ai, *bi;
+
+ assert(is_Block(a) && is_Block(b));
+ ai = get_dom_info(a);
+ bi = get_dom_info(b);
+ return bi->tree_pre_num - ai->tree_pre_num
+ <= ai->max_subtree_pre_num - ai->tree_pre_num;
+}
+
+ir_node *get_Block_dominated_first(const ir_node *bl)
+{
+ assert(is_Block(bl));
+ return get_dom_info(bl)->first;
+}
+
+ir_node *get_Block_dominated_next(const ir_node *bl)
+{
+ assert(is_Block(bl));
+ return get_dom_info(bl)->next;
+}
+
+void dom_tree_walk(ir_node *bl, irg_walk_func *pre,
+ irg_walk_func *post, void *env)
+{
+ ir_node *p;
+
+ if(pre)
+ pre(bl, env);
+
+ dominates_for_each(bl, p) {
+ dom_tree_walk(p, pre, post, env);
+ }
+
+ if(post)
+ post(bl, env);
+}
+
+void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
+ irg_walk_func *post, void *env)
+{
+ /* The root of the dominator tree should be the start node. */
+ ir_node *root = get_irg_start_block(irg);
+
+ assert(irg->dom_state == dom_consistent
+ && "The dominators of the irg must be consistent");
+ assert(root && "The start block of the graph is NULL?");
+ assert(get_dom_info(root)->idom == NULL
+ && "The start node in the graph must be the root of the dominator tree");
+ dom_tree_walk(root, pre, post, env);
+}
+
+static void assign_tree_pre_order(ir_node *bl, void *data)
+{
+ unsigned *num = data;
+ dom_info *bi = get_dom_info(bl);
+ bi->tree_pre_num = (*num)++;
+}
-/**********************************************************************/
-/** Building and Removing the dominator datasturcture **/
-/** **/
-/** **/
-/** **/
-/** **/
-/** **/
-/** **/
-/** **/
-/** .**/
-/** **/
-/** **/
-/** **/
-/** **/
-/** **/
-/** **/
-/**********************************************************************/
-
-void count_and_init_blocks(ir_node *bl, void *env) {
+static void assign_tree_pre_order_max(ir_node *bl, void *data)
+{
+ dom_info *bi = get_dom_info(bl);
+ ir_node *p;
+ unsigned max = 0;
+ unsigned children = 0;
+
+ for(p = bi->first; p; p = get_dom_info(p)->next) {
+ unsigned max_p = get_dom_info(p)->max_subtree_pre_num;
+ max = max > max_p ? max : max_p;
+ children++;
+ }
+
+ bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
+ assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
+}
+
+/*--------------------------------------------------------------------*/
+/* Building and Removing the dominator datastructure */
+/*--------------------------------------------------------------------*/
+
+static void count_and_init_blocks(ir_node *bl, void *env) {
int *n_blocks = (int *) env;
(*n_blocks) ++;
+ memset(get_dom_info(bl), 0, sizeof(dom_info));
set_Block_idom(bl, NULL);
set_Block_pre_num(bl, -1);
set_Block_dom_depth(bl, -1);
} dom_env;
-void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent, tmp_dom_info *tdi_list, int* used) {
+
+/* Walks Blocks along the out datastructure. If recursion started with
+ Start block misses control dead blocks. */
+static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
+ tmp_dom_info *tdi_list, int* used) {
tmp_dom_info *tdi;
int i;
assert(get_irn_op(bl) == op_Block);
- if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl)) return;
+ if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
+ return;
mark_Block_block_visited(bl);
set_Block_pre_num(bl, *used);
- //printf(" used: %d ", *used); DDMN(bl);
-
tdi = &tdi_list[*used];
++(*used);
}
}
-
static void
dom_compress (tmp_dom_info *v)
{
/* if V is a root, return v, else return the vertex u, not being the
root, with minimum u->semi on the path from v to its root. */
-inline static tmp_dom_info*
+INLINE static tmp_dom_info*
dom_eval (tmp_dom_info *v)
{
if (!v->ancestor) return v;
}
/* make V W's ancestor */
-inline static void
+INLINE static void
dom_link (tmp_dom_info *v, tmp_dom_info *w)
{
w->ancestor = v;
ir_graph *rem = current_ir_graph;
int n_blocks, used, i, j;
tmp_dom_info *tdi_list; /* Ein Golf? */
- dom_env de;
current_ir_graph = irg;
n_blocks = 0;
irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks, NULL, &n_blocks);
- //printf("n_blocks is %d\n", n_blocks);
-
/* Memory for temporary information. */
- tdi_list = (tmp_dom_info *) calloc(n_blocks, sizeof(tmp_dom_info));
+ tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
/* We need the out datastructure. */
if (current_ir_graph->outs_state != outs_consistent)
compute_outs(current_ir_graph);
- /** Initialize the temporary information, add link to parent. We don't do
- this with a standard walker as passing the parent to the sons isn't
- simple. **/
+ /* this with a standard walker as passing the parent to the sons isn't
+ simple. */
used = 0;
inc_irg_block_visited(current_ir_graph);
init_tmp_dom_info(get_irg_start_block(current_ir_graph), NULL, tdi_list, &used);
/* If not all blocks are reachable from Start by out edges this assertion
- fails. */
- //assert(used == n_blocks && "Precondition for dom construction violated");
+ fails.
+ assert(used == n_blocks && "Precondition for dom construction violated"); */
n_blocks = used;
- //printf("used is %d\n", used);
-
for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
+ int irn_arity;
tmp_dom_info *w = &tdi_list[i];
tmp_dom_info *v;
- //printf(" cfgpreds: %d ", get_Block_n_cfgpreds(w->block)); DDMN(w->block);
-
/* Step 2 */
- for (j = 0; j < get_irn_arity(w->block); j++) {
- ir_node *pred = get_nodes_Block(get_Block_cfgpred(w->block, j));
+ irn_arity = get_irn_arity(w->block);
+ for (j = 0; j < irn_arity; j++) {
+ ir_node *cf_op = get_Block_cfgpred(w->block, j);
+ ir_node *pred = get_nodes_block(cf_op);
tmp_dom_info *u;
- if ((is_Bad(pred)) || (get_Block_pre_num (pred) == -1))
+ if ((is_Bad(cf_op)) || (is_Bad(pred)) ||
+ (get_Block_pre_num (pred) == -1))
continue; /* control-dead */
u = dom_eval (&tdi_list[get_Block_pre_num(pred)]);
}
/* clean up */
- free(tdi_list);
+ /* free(tdi_list); @@@ does not work !!?? */
current_ir_graph = rem;
+
+ /* Do a walk over the tree and assign the tree pre orders. */
+ {
+ unsigned tree_pre_order = 0;
+ dom_tree_walk_irg(irg, assign_tree_pre_order,
+ assign_tree_pre_order_max, &tree_pre_order);
+ }
}
void free_dom_and_peace(ir_graph *irg) {
/* Update graph state */
assert(get_irg_phase_state(current_ir_graph) != phase_building);
- current_ir_graph->dom_state = no_dom;
+ current_ir_graph->dom_state = dom_none;
- /* @@@ free */
+ /* With the implementation right now there is nothing to free,
+ but better call it anyways... */
}
-
-
-#if 0
-/* Dominator Tree */
-
-/* temporary type used while constructing the dominator tree. */
-typedef struct tmp_dom_info tmp_dom_info;
-struct tmp_dom_info {
- ir_node *region;
-
- tmp_dom_info *semi; /* semidominator */
- tmp_dom_info *parent;
- tmp_dom_info *label; /* used for LINK and EVAL */
- tmp_dom_info *ancestor; /* used for LINK and EVAL */
- tmp_dom_info *dom; /* After step 3, if the semidominator
- of w is its immediate dominator, then w->dom is the immediate
- dominator of w. Otherwise w->dom is a vertex v whose number is
- smaller than w and whose immediate dominator is also w's immediate
- dominator. After step 4, w->dom is the immediate dominator of w. */
- tmp_dom_info *bucket; /* set of vertices with same semidominator */
-};
-
-static int
-dom_count_regions (ir_node *n)
-{
- int i, count = 1;
-
- n->visit = ir_visited;
-
- for (i = IR_ARITY (n); i > 0; --i) {
- ir_node *pr = prev_region (n, i);
- if (pr && pr->visit != ir_visited) {
- count += dom_count_regions (pr);
- }
- }
- return count;
-}
-
-struct dt_desc { tmp_dom_info *dt; int used;};
-
-static void
-dom_setup (ir_node *n, tmp_dom_info *parent, struct dt_desc *dt_desc)
-{
- tmp_dom_info *dt = &dt_desc->dt[dt_desc->used];
- int i;
-
- if (n->visit == ir_visited) return;
- n->visit = ir_visited;
-
- assert (IR_CFG_NODE (n));
-
- n->data.r.pre_num = dt_desc->used;
- dt->semi = dt;
- dt->label = dt;
- dt->ancestor = NULL;
- dt->bucket = NULL;
- dt->parent = parent;
- dt->region = n;
- ++(dt_desc->used);
-
- for (i = 0; i < n->data.r.cfg_outs; ++i) {
- dom_setup (n->data.r.cfg_out[i], dt, dt_desc);
- }
-}
-
-static void
-dom_compress (tmp_dom_info *v)
-{
- assert (v->ancestor);
- if (v->ancestor->ancestor) {
- dom_compress (v->ancestor);
- if (v->ancestor->label->semi < v->label->semi) {
- v->label = v->ancestor->label;
- }
- v->ancestor = v->ancestor->ancestor;
- }
-}
-
-/* if V is a root, return v, else return the vertex u, not being the
- root, with minimum u->semi on the path from v to its root. */
-static tmp_dom_info*
-dom_eval (tmp_dom_info *v)
-{
- if (!v->ancestor) return v;
- dom_compress (v);
- return v->label;
-}
-
-/* make V W's ancestor */
-static void
-dom_link (tmp_dom_info *v, tmp_dom_info *w)
-{
- w->ancestor = v;
-}
-
-void
-irg_gen_idom (ir_graph *irg)
-{
- int regions, i;
- tmp_dom_info *dt;
- struct dt_desc dt_desc;
-
- if (!(irg->state & irgs_has_CFG)) irg_gen_out (irg);
-
- ++ir_visited;
- regions = 0;
- /* walk all the artificially kept alive parts of the CFG instead of
- the CFG beginning from the Start just for fun and safety */
- keep_alives_in_arr (irg);
- for (i = ARR_LEN (irg->keep.alive) - 1; i >= 0; --i)
- if ( IR_CFG_NODE (irg->keep.alive[i])
- && irg->keep.alive[i]->visit != ir_visited)
- regions += dom_count_regions (irg->keep.alive[i]);
-
- dt = alloca ((regions+1) * sizeof (tmp_dom_info));
- memset (dt, 0, (regions+1) * sizeof (tmp_dom_info));
-
- /* Step 1 */
- dt_desc.dt = dt;
- dt_desc.used = 1;
- ++ir_visited;
- dom_setup (irg->start, NULL, &dt_desc);
-
- /* This assert will fail, if not all Regions are reachable by
- walking the CFG starting from Start, that is when there is
- [control] dead code, violating the single entry precondition of
- this algorithm. */
- assert (dt_desc.used == regions + 1);
-
- for (i = regions; i > 1; --i) {
- tmp_dom_info *w = &dt[i];
- tmp_dom_info *v;
- int j, r_ins;
-
- /* Step 2 */
- r_ins = IR_ARITY (w->region);
- for (j = 1; j <= r_ins; ++j) {
- ir_node *prev = prev_region (w->region, j);
- tmp_dom_info *u;
-
- if (!prev) continue; /* control-dead */
-
- u = dom_eval (&dt[prev->data.r.pre_num]);
- if (u->semi < w->semi) w->semi = u->semi;
- }
- /* Add w to w->semi's bucket. w is in exactly one bucket, so
- buckets can ben implemented as linked lists. */
- w->bucket = w->semi->bucket;
- w->semi->bucket = w;
-
- dom_link (w->parent, w);
-
- /* Step 3 */
- while ((v = w->parent->bucket)) {
- tmp_dom_info *u;
- /* remove v from w->parent->bucket */
- w->parent->bucket = v->bucket;
- v->bucket = NULL;
-
- u = dom_eval (v);
- v->dom = u->semi < v->semi ? u : w->parent;
- }
- }
- /* Step 4 */
- dt[1].dom = NULL;
- dt[1].region->data.r.idom = NULL;
- dt[1].region->data.r.dom_depth = 1;
- for (i = 2; i <= regions; ++i) {
- tmp_dom_info *w = &dt[i];
-
- if (w->dom != w->semi) w->dom = w->dom->dom;
- w->region->data.r.idom = w->dom->region;
- w->region->data.r.dom_depth = w->dom->region->data.r.dom_depth + 1;
- }
- current_ir_graph = sirg;
-}
-
-#endif
projects / libfirm / blobdiff