X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firdom.c;h=cf47222367d49e0aa6222ec67df1148744b7a250;hb=d0d85962ef52c14950db90e5981a7bea36023ab3;hp=607821c27fd5137bb2e291c1505c200870abaa71;hpb=dced6fdc8948497e65093b3de3b818f1ecc59c6a;p=libfirm

diff --git a/ir/ana/irdom.c b/ir/ana/irdom.c
index 607821c27..cf4722236 100644
--- a/ir/ana/irdom.c
+++ b/ir/ana/irdom.c
@@ -14,6 +14,12 @@
 #include "config.h"
 #endif
 
+#ifdef HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
 #ifdef HAVE_STRING_H
 #include <string.h>
 #endif
@@ -26,6 +32,8 @@
 #include "irgraph_t.h"   /* To access state field. */
 #include "irnode_t.h"
 #include "ircons_t.h"
+#include "array.h"
+#include "iredges.h"
 
 
 #define get_dom_info(bl)  (&(bl)->attr.block.dom)
@@ -173,6 +181,92 @@ int block_dominates(const ir_node *a, const ir_node *b)
 	return 0;
 }
 
+/* Returns the smallest common dominator block of two nodes. */
+ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b)
+{
+	ir_node *bl_a   = is_Block(a) ? a : get_nodes_block(a);
+	ir_node *bl_b   = is_Block(b) ? b : get_nodes_block(b);
+	ir_node *dom_bl = NULL;
+
+	/* Check if block of a dominates block of b */
+	if (block_dominates(bl_a, bl_b))
+		dom_bl = bl_a;
+	/* Check if block of b dominates block of a */
+	else if (block_dominates(bl_b, bl_a))
+		dom_bl = bl_b;
+	else {
+		/* walk up dominator tree and search for first block dominating a and b */
+		while (! dom_bl) {
+			bl_a = get_Block_idom(bl_a);
+
+			assert(! is_Bad(bl_a) && "block is dead?");
+
+			if (block_dominates(bl_a, bl_b))
+				dom_bl = bl_a;
+		}
+	}
+
+	return dom_bl;
+}
+
+/* Returns the smallest common dominator block of all users of a node. */
+ir_node *node_users_smallest_common_dominator(ir_node *irn, int handle_phi)
+{
+	int n, j, i = 0, success;
+	ir_node **user_blocks, *dom_bl;
+	const ir_edge_t *edge;
+
+	assert(! is_Block(irn) && "WRONG USAGE of node_users_smallest_common_dominator");
+	assert(edges_activated(get_irn_irg(irn)) && "need edges activated");
+
+	n = get_irn_n_edges(irn);
+
+	/* get array to hold all block of the node users */
+	NEW_ARR_A(ir_node *, user_blocks, n);
+	foreach_out_edge(irn, edge) {
+		ir_node *src = get_edge_src_irn(edge);
+
+		if (is_Phi(src) && handle_phi) {
+			/* get the corresponding cfg predecessor block if phi handling requested */
+			j  = get_edge_src_pos(edge);
+			assert(j >= 0 && "kaputt");
+			user_blocks[i++] = get_Block_cfgpred_block(get_nodes_block(src), j);
+		}
+		else
+			user_blocks[i++] = is_Block(src) ? src : get_nodes_block(src);
+	}
+
+	assert(i == n && "get_irn_n_edges probably broken");
+
+	/* in case of only one user: return the block of the user */
+	if (n == 1)
+		return user_blocks[0];
+
+	i = 0;
+	/* search the smallest block dominating all user blocks */
+	do {
+		dom_bl  = node_smallest_common_dominator(user_blocks[i], user_blocks[i + 1]);
+		success = 1;
+
+		/* check if this block dominates all remaining blocks as well */
+		for (j = i + 2; j < n; j++) {
+			if (! block_dominates(dom_bl, user_blocks[j]))
+				success = 0;
+		}
+
+		if (success)
+			break;
+
+		/* inherit the dominator block of the first (i + 1) users */
+		user_blocks[++i] = dom_bl;
+	} while (i < n - 1);
+
+	assert(success && "no block found dominating all users");
+
+	return dom_bl;
+}
+
+
 /* Get the first node in the list of nodes dominated by a given block. */
 ir_node *get_Block_dominated_first(const ir_node *bl)
 {
@@ -274,7 +368,7 @@ void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
 	/* The root of the dominator tree should be the End block. */
 	ir_node *root = get_irg_end_block(irg);
 
-  assert(irg->pdom_state == dom_consistent
+	assert(irg->pdom_state == dom_consistent
 			&& "The dominators of the irg must be consistent");
 	assert(root && "The end block of the graph is NULL?");
 	assert(get_pdom_info(root)->idom == NULL
@@ -334,33 +428,20 @@ static void assign_tree_postdom_pre_order_max(ir_node *bl, void *data)
 }
 
 /*--------------------------------------------------------------------*/
-/*  Building and Removing the dominator datastructure                 */
+/*  Building and Removing the dominator data structure                */
 /*--------------------------------------------------------------------*/
 
-/**
- * count the number of blocks and clears the dominance info
- */
-static void count_and_init_blocks_dom(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_dom_pre_num(bl, -1);
-  set_Block_dom_depth(bl, -1);
-}
-
 /**
  * count the number of blocks and clears the post dominance info
  */
 static void count_and_init_blocks_pdom(ir_node *bl, void *env) {
-  int *n_blocks = (int *) env;
-  (*n_blocks) ++;
+	int *n_blocks = (int *) env;
+	(*n_blocks) ++;
 
 	memset(get_pdom_info(bl), 0, sizeof(dom_info));
-  set_Block_ipostdom(bl, NULL);
-  set_Block_postdom_pre_num(bl, -1);
-  set_Block_postdom_depth(bl, -1);
+	set_Block_ipostdom(bl, NULL);
+	set_Block_postdom_pre_num(bl, -1);
+	set_Block_postdom_depth(bl, -1);
 }
 
 /** temporary type used while constructing the dominator / post dominator tree. */
@@ -389,35 +470,36 @@ typedef struct {
 
 
 /**
- * Walks Blocks along the out datastructure.  If recursion started with
+ * Walks Blocks along the out data structure.  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_list, int *used, int n_blocks) {
   tmp_dom_info *tdi;
   int i;
 
-  assert(get_irn_op(bl) == op_Block);
+  assert(is_Block(bl));
   if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
     return;
   mark_Block_block_visited(bl);
   set_Block_dom_pre_num(bl, *used);
 
+  assert(*used < n_blocks);
   tdi = &tdi_list[*used];
   ++(*used);
 
-  tdi->semi = tdi;
-  tdi->label = tdi;
+  tdi->semi     = tdi;
+  tdi->label    = tdi;
   tdi->ancestor = NULL;
-  tdi->bucket = NULL;
-  tdi->parent = parent;
-  tdi->block = bl;
+  tdi->bucket   = NULL;
+  tdi->parent   = parent;
+  tdi->block    = bl;
 
   /* Iterate */
-  for(i = 0; i < get_Block_n_cfg_outs(bl); i++) {
-    ir_node *pred = get_Block_cfg_out(bl, i);
-    assert(get_irn_opcode(pred) == iro_Block);
-    init_tmp_dom_info(pred, tdi, tdi_list, used);
+  for (i = get_Block_n_cfg_outs_ka(bl) - 1; i >= 0; --i) {
+    ir_node *pred = get_Block_cfg_out_ka(bl, i);
+    assert(is_Block(pred));
+    init_tmp_dom_info(pred, tdi, tdi_list, used, n_blocks);
   }
 }
 
@@ -426,16 +508,17 @@ static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
  * End block misses blocks in endless loops.
  */
 static void init_tmp_pdom_info(ir_node *bl, tmp_dom_info *parent,
-			      tmp_dom_info *tdi_list, int* used) {
+                               tmp_dom_info *tdi_list, int* used, int n_blocks) {
   tmp_dom_info *tdi;
   int i;
 
-  assert(get_irn_op(bl) == op_Block);
+  assert(is_Block(bl));
   if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
     return;
   mark_Block_block_visited(bl);
   set_Block_postdom_pre_num(bl, *used);
 
+  assert(*used < n_blocks);
   tdi = &tdi_list[*used];
   ++(*used);
 
@@ -447,12 +530,28 @@ static void init_tmp_pdom_info(ir_node *bl, tmp_dom_info *parent,
   tdi->block = bl;
 
   /* Iterate */
-  for(i = 0; i < get_Block_n_cfgpreds(bl); i++) {
+  for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i) {
     ir_node *pred = get_Block_cfgpred_block(bl, i);
     if (is_Bad(pred))
       continue;
     assert(is_Block(pred));
-    init_tmp_pdom_info(pred, tdi, tdi_list, used);
+    init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
+  }
+
+  /* Handle keep-alives. Note that the preprocessing
+     in init_construction() had already killed all
+     phantom keep-alive edges. All remaining block keep-alives
+     are really edges to endless loops.
+   */
+  if (bl == get_irg_end_block(current_ir_graph)) {
+    ir_node *end = get_irg_end(current_ir_graph);
+
+    for (i = get_irn_arity(end) - 1; i >= 0; --i) {
+      ir_node *pred = get_irn_n(end, i);
+
+      if (is_Block(pred))
+        init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
+    }
   }
 }
 
@@ -485,6 +584,75 @@ INLINE static void dom_link(tmp_dom_info *v, tmp_dom_info *w)
   w->ancestor = v;
 }
 
+/**
+ * Walker: count the number of blocks and clears the dominance info
+ */
+static void count_and_init_blocks_dom(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_dom_pre_num(bl, -1);
+  set_Block_dom_depth(bl, -1);
+}
+
+/**
+ * Initialize the dominance/postdominance construction:
+ *
+ * - count the number of blocks
+ * - clear the dominance info
+ * - remove Block-keepalives of live blocks to reduce
+ *   the number of "phantom" block edges
+ *
+ * @param irg  the graph
+ * @param pre  a walker function that will be called for every block in the graph
+ */
+static int init_construction(ir_graph *irg, irg_walk_func *pre) {
+  ir_graph *rem = current_ir_graph;
+  ir_node *end;
+  int arity;
+  int n_blocks = 0;
+
+  current_ir_graph = irg;
+
+  /* this visits only the reachable blocks */
+  irg_block_walk(get_irg_end_block(irg), pre, NULL, &n_blocks);
+
+  /* now visit the unreachable (from End) Blocks and remove unnecessary keep-alives */
+  end   = get_irg_end(irg);
+  arity = get_End_n_keepalives(end);
+  if (arity) {    /* we have keep-alives */
+    ir_node **in;
+    int i, j;
+
+    NEW_ARR_A(ir_node *, in, arity);
+    for (i = j = 0; i < arity; i++) {
+      ir_node *pred = get_End_keepalive(end, i);
+
+      if (get_irn_op(pred) == op_Block) {
+        if (Block_not_block_visited(pred)) {
+          /* we found a endless loop */
+          dec_irg_block_visited(irg);
+          irg_block_walk(pred, pre, NULL, &n_blocks);
+        }
+        else
+          continue;
+      }
+      in[j++] = pred;
+    }
+    if (j != arity) {
+      /* we kill some Block keep-alives */
+      set_End_keepalives(end, j, in);
+      set_irg_outs_inconsistent(irg);
+    }
+  }
+
+  current_ir_graph = rem;
+  return n_blocks;
+}
+
+
 /* Computes the dominator trees.  Sets a flag in irg to "dom_consistent".
    If the control flow of the graph is changed this flag must be set to
    "dom_inconsistent".  */
@@ -496,28 +664,27 @@ void compute_doms(ir_graph *irg) {
   current_ir_graph = irg;
 
   /* Update graph state */
-  assert(get_irg_phase_state(current_ir_graph) != phase_building);
-  current_ir_graph->dom_state = dom_consistent;
+  assert(get_irg_phase_state(irg) != phase_building);
+  irg->dom_state = dom_consistent;
 
   /* Count the number of blocks in the graph. */
-  n_blocks = 0;
-  irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks_dom, NULL, &n_blocks);
+  n_blocks = init_construction(irg, count_and_init_blocks_dom);
 
   /* Memory for temporary information. */
   tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
 
-  /* We need the out datastructure. */
-  if (current_ir_graph->outs_state != outs_consistent)
-    compute_irg_outs(current_ir_graph);
+  /* We need the out data structure. */
+  assure_irg_outs(irg);
 
   /* 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);
+  inc_irg_block_visited(irg);
+  init_tmp_dom_info(get_irg_start_block(irg), NULL, tdi_list, &used, n_blocks);
   /* If not all blocks are reachable from Start by out edges this assertion
      fails.
      assert(used == n_blocks && "Precondition for dom construction violated"); */
+  assert(used <= n_blocks && "Precondition for dom construction violated");
   n_blocks = used;
 
 
@@ -528,7 +695,7 @@ void compute_doms(ir_graph *irg) {
 
     /* Step 2 */
     irn_arity = get_irn_arity(w->block);
-    for (j = 0;  j < irn_arity;  j++) {
+    for (j = 0; j < irn_arity;  j++) {
       ir_node *pred = get_Block_cfgpred_block(w->block, j);
       tmp_dom_info *u;
 
@@ -538,8 +705,26 @@ void compute_doms(ir_graph *irg) {
       u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
       if (u->semi < w->semi) w->semi = u->semi;
     }
+
+    /* handle keep-alives if we are at the end block */
+    if (w->block == get_irg_end_block(irg)) {
+      ir_node *end = get_irg_end(irg);
+
+      irn_arity = get_irn_arity(end);
+      for (j = 0; j < irn_arity;  j++) {
+        ir_node *pred = get_irn_n(end, j);
+        tmp_dom_info *u;
+
+        if (is_no_Block(pred) || get_Block_dom_pre_num(pred) == -1)
+          continue;	/* control-dead */
+
+        u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
+        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. */
+       buckets can been implemented as linked lists. */
     w->bucket = w->semi->bucket;
     w->semi->bucket = w;
 
@@ -564,17 +749,25 @@ void compute_doms(ir_graph *irg) {
   tdi_list[0].dom = NULL;
   set_Block_idom(tdi_list[0].block, NULL);
   set_Block_dom_depth(tdi_list[0].block, 1);
-  for (i = 1;  i < n_blocks;  i++) {
+  for (i = 1; i < n_blocks;  i++) {
     tmp_dom_info *w = &tdi_list[i];
+    int depth;
+
+    if (! w->dom)
+      continue; /* control dead */
 
     if (w->dom != w->semi) w->dom = w->dom->dom;
     set_Block_idom(w->block, w->dom->block);
-    set_Block_dom_depth(w->block, get_Block_dom_depth(w->dom->block) + 1);
+
+    /* blocks dominated by dead one's are still dead */
+    depth = get_Block_dom_depth(w->dom->block);
+    if (depth > 0)
+      ++depth;
+    set_Block_dom_depth(w->block, depth);
   }
 
   /* clean up */
   free(tdi_list);
-  current_ir_graph = rem;
 
   /* Do a walk over the tree and assign the tree pre orders. */
   {
@@ -582,6 +775,12 @@ void compute_doms(ir_graph *irg) {
     dom_tree_walk_irg(irg, assign_tree_dom_pre_order,
       assign_tree_dom_pre_order_max, &tree_pre_order);
   }
+  current_ir_graph = rem;
+}
+
+void assure_doms(ir_graph *irg) {
+  if (get_irg_dom_state(irg) != dom_consistent)
+    compute_doms(irg);
 }
 
 void free_dom(ir_graph *irg) {
@@ -604,25 +803,23 @@ void compute_postdoms(ir_graph *irg) {
   current_ir_graph = irg;
 
   /* Update graph state */
-  assert(get_irg_phase_state(current_ir_graph) != phase_building);
-  current_ir_graph->pdom_state = dom_consistent;
+  assert(get_irg_phase_state(irg) != phase_building);
+  irg->pdom_state = dom_consistent;
 
   /* Count the number of blocks in the graph. */
-  n_blocks = 0;
-  irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks_pdom, NULL, &n_blocks);
+  n_blocks = init_construction(irg, count_and_init_blocks_pdom);
 
   /* Memory for temporary information. */
   tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
 
-  /* We need the out datastructure. */
-  if (current_ir_graph->outs_state != outs_consistent)
-    compute_irg_outs(current_ir_graph);
+  /* We need the out data structure. */
+  assure_irg_outs(irg);
 
   /* 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_pdom_info(get_irg_end_block(current_ir_graph), NULL, tdi_list, &used);
+  inc_irg_block_visited(irg);
+  init_tmp_pdom_info(get_irg_end_block(irg), NULL, tdi_list, &used, n_blocks);
   /* If not all blocks are reachable from End by cfg edges this assertion
      fails.
      assert(used == n_blocks && "Precondition for dom construction violated"); */
@@ -635,9 +832,9 @@ void compute_postdoms(ir_graph *irg) {
     tmp_dom_info *v;
 
     /* Step 2 */
-    irn_arity = get_Block_n_cfg_outs(w->block);
+    irn_arity = get_Block_n_cfg_outs_ka(w->block);
     for (j = 0;  j < irn_arity;  j++) {
-      ir_node *succ = get_Block_cfg_out(w->block, j);
+      ir_node *succ = get_Block_cfg_out_ka(w->block, j);
       tmp_dom_info *u;
 
       if (get_Block_postdom_pre_num (succ) == -1)
@@ -682,7 +879,6 @@ void compute_postdoms(ir_graph *irg) {
 
   /* clean up */
   free(tdi_list);
-  current_ir_graph = rem;
 
   /* Do a walk over the tree and assign the tree pre orders. */
   {
@@ -690,6 +886,12 @@ void compute_postdoms(ir_graph *irg) {
     postdom_tree_walk_irg(irg, assign_tree_postdom_pre_order,
       assign_tree_postdom_pre_order_max, &tree_pre_order);
   }
+  current_ir_graph = rem;
+}
+
+void assure_postdoms(ir_graph *irg) {
+  if (get_irg_postdom_state(irg) != dom_consistent)
+    compute_postdoms(irg);
 }
 
 void free_postdom(ir_graph *irg) {