X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fir%2Firgwalk.c;h=cf111f3fbe2d00ea131060d1330d6bfd8bdfee10;hb=94af5ee1dc6e88b9a97d2d0b2985d64025881617;hp=740758fc24e1cf8c5597f6207c755d92a57ce46f;hpb=79df37c097fe8cfb7d8e56d30b658f7ce8f6655d;p=libfirm

diff --git a/ir/ir/irgwalk.c b/ir/ir/irgwalk.c
index 740758fc2..cf111f3fb 100644
--- a/ir/ir/irgwalk.c
+++ b/ir/ir/irgwalk.c
@@ -1,83 +1,412 @@
-/* Copyright (C) 1998 - 2000 by Universitaet Karlsruhe
-** All rights reserved.
-**
-** Author: Boris Boesler
-**
-** traverse an ir graph
-** - execute the pre function before recursion
-** - execute the post function after recursion
+/*
+ * Project:     libFIRM
+ * File name:   ir/ir/irgwalk.c
+ * Purpose:
+ * Author:      Boris Boesler
+ * Modified by: Goetz Lindenmaier
+ * Created:
+ * CVS-ID:      $Id$
+ * Copyright:   (c) 1999-2003 Universität Karlsruhe
+ * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ */
+
+/**
+* traverse an ir graph
+* - execute the pre function before recursion
+* - execute the post function after recursion
 */
 
-# include "irnode.h"
-# include "irgraph.h" /* visited flag */
 
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
 
-void irg_walk_2(ir_node *node,
-	      void (pre)(ir_node*, void*), void (post)(ir_node*, void*),
-	      void *env)
-{
+#include <stdlib.h>
+
+#include "irnode_t.h"
+#include "irgraph_t.h" /* visited flag */
+#include "irprog.h"
+#include "irgwalk.h"
+#include "typewalk.h"
+#include "firmstat.h"
+#include "ircgcons.h"
+
+#include "eset.h"
+#include "array.h"
+
+/* walk over an interprocedural graph (callgraph). Visits only graphs in irg_set. */
+static void irg_walk_cg(ir_node * node, int visited, eset * irg_set,
+                        irg_walk_func *pre, irg_walk_func *post, void * env) {
   int i;
+  ir_graph * rem = current_ir_graph;
+  ir_node * pred;
 
-  assert(node);
-  if(get_irn_visited(node) < get_irg_visited(current_ir_graph)) {
-    set_irn_visited(node, get_irg_visited(current_ir_graph));
-    if(pre) {
-      pre(node, env);
+  assert(node && node->kind == k_ir_node);
+  if (get_irn_visited(node) >= visited) return;
+
+  set_irn_visited(node, visited);
+
+  if (pre) pre(node, env);
+
+  pred = skip_Proj(node);
+  if (get_irn_op(pred) == op_CallBegin
+      || get_irn_op(pred) == op_EndReg
+      || get_irn_op(pred) == op_EndExcept) {
+    current_ir_graph = get_irn_irg(pred);
+  }
+
+  if (is_no_Block(node)) { /* not block */
+    irg_walk_cg(get_nodes_block(node), visited, irg_set, pre, post, env);
+  }
+
+  if (get_irn_op(node) == op_Block) { /* block */
+    for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+      ir_node * exec = get_irn_n(node, i);
+      ir_node * pred = skip_Proj(exec);
+      if ((get_irn_op(pred) != op_CallBegin
+           && get_irn_op(pred) != op_EndReg
+           && get_irn_op(pred) != op_EndExcept)
+          || eset_contains(irg_set, get_irn_irg(pred))) {
+        irg_walk_cg(exec, visited, irg_set, pre, post, env);
+      }
     }
+  } else if (get_irn_op(node) == op_Filter) { /* filter */
+    for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+      ir_node * pred = get_irn_n(node, i);
+      if (get_irn_op(pred) == op_Unknown || get_irn_op(pred) == op_Bad) {
+        irg_walk_cg(pred, visited, irg_set, pre, post, env);
+      } else {
+        ir_node * exec;
+        exec = skip_Proj(get_Block_cfgpred(get_nodes_block(node), i));
 
-    if (is_no_Block(node))
-      irg_walk_2(get_nodes_Block(node), pre, post, env);
-    for(i = get_irn_arity(node) - 1; i >= 0; --i) {
-      irg_walk_2(get_irn_n(node, i), pre, post, env);
+        if (op_Bad == get_irn_op (exec)) {
+          continue;
+        }
+
+        assert(get_irn_op(exec) == op_CallBegin
+               || get_irn_op(exec) == op_EndReg
+               || get_irn_op(exec) == op_EndExcept);
+        if (eset_contains(irg_set, get_irn_irg(exec))) {
+          current_ir_graph = get_irn_irg(exec);
+          irg_walk_cg(pred, visited, irg_set, pre, post, env);
+          current_ir_graph = rem;
+        }
+      }
+    }
+  } else {                      /* everything else */
+    for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+      irg_walk_cg(get_irn_n(node, i), visited, irg_set, pre, post, env);
+    }
+  }
+
+  if (post) post(node, env);
+
+  current_ir_graph = rem;
+}
+
+
+/* Insert all ir_graphs in irg_set, that are (transitive) reachable. */
+static void collect_irgs(ir_node * node, eset * irg_set) {
+  if (get_irn_op(node) == op_Call) {
+    int i;
+    for (i = get_Call_n_callees(node) - 1; i >= 0; --i) {
+      entity * ent = get_Call_callee(node, i);
+      ir_graph * irg = ent ? get_entity_irg(ent) : NULL;
+      if (irg && !eset_contains(irg_set, irg)) {
+        eset_insert(irg_set, irg);
+        irg_walk_graph(irg, (irg_walk_func *) collect_irgs, NULL, irg_set);
+      }
     }
+  }
+}
+
+/**
+ * specialized version of irg_walk_2, called if only pre callback exists
+ */
+static void
+irg_walk_2_pre(ir_node *node, irg_walk_func *pre, void * env) {
+  int i;
+  set_irn_visited(node, current_ir_graph->visited);
+
+  pre(node, env);
+
+  if (node->op != op_Block) {
+    ir_node *pred = get_irn_n(node, -1);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_pre(pred, pre, env);
+  }
+  for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+    ir_node *pred = get_irn_n(node, i);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_pre(pred, pre, env);
+  }
+}
+
+/**
+ * specialized version of irg_walk_2, called if only post callback exists
+ */
+static void
+irg_walk_2_post(ir_node *node, irg_walk_func *post, void * env) {
+  int i;
+  set_irn_visited(node, current_ir_graph->visited);
+
+  if (node->op != op_Block) {
+    ir_node *pred = get_irn_n(node, -1);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_post(pred, post, env);
+  }
+  for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+    ir_node *pred = get_irn_n(node, i);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_post(pred, post, env);
+  }
+
+  post(node, env);
+}
+
+/**
+ * specialized version of irg_walk_2, called if pre and post callbacks exist
+ */
+static void
+irg_walk_2_both(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env) {
+  int i;
+  set_irn_visited(node, current_ir_graph->visited);
+
+  pre(node, env);
+
+  if (node->op != op_Block) {
+    ir_node *pred = get_irn_n(node, -1);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_both(pred, pre, post, env);
+  }
+  for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+    ir_node *pred = get_irn_n(node, i);
+    if (pred->visited < current_ir_graph->visited)
+      irg_walk_2_both(pred, pre, post, env);
+  }
+
+  post(node, env);
+}
+
+/**
+ * Intraprozedural graph walker.
+ */
+static void
+irg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
+{
+  if (node->visited < current_ir_graph->visited) {
+    if      (!post) irg_walk_2_pre (node, pre, env);
+    else if (!pre)  irg_walk_2_post(node, post, env);
+    else            irg_walk_2_both(node, pre, post, env);
+  }
+}
+
+/*
+ * generic graph walker
+ */
+void irg_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
+{
+  assert(node  && node->kind==k_ir_node);
 
-    if(post)
-      post(node, env);
+  if (interprocedural_view) {
+    eset * irg_set = eset_create();
+    int visited;
+    ir_graph * irg;
+    assert(get_irp_ip_view_state() == ip_view_valid);
+
+    interprocedural_view = false;
+    eset_insert(irg_set, current_ir_graph);
+    irg_walk(node, (irg_walk_func *) collect_irgs, NULL, irg_set);
+    interprocedural_view = true;
+    visited = get_max_irg_visited() + 1;
+    for (irg = eset_first(irg_set); irg; irg = eset_next(irg_set)) {
+      set_irg_visited(irg, visited);
+    }
+    irg_walk_cg(node, visited, irg_set, pre, post, env);
+    eset_destroy(irg_set);
+  } else {
+    inc_irg_visited(current_ir_graph);
+    irg_walk_2(node, pre, post, env);
   }
   return;
 }
 
 
-void irg_walk(ir_node *node,
-	      void (pre)(ir_node*, void*), void (post)(ir_node*, void*),
-	      void *env)
+void irg_walk_graph(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env) {
+  ir_graph * rem = current_ir_graph;
+
+  stat_irg_walk(irg, (void *)pre, (void *)post);
+  current_ir_graph = irg;
+  irg_walk(get_irg_end(irg), pre, post, env);
+  current_ir_graph = rem;
+}
+
+/* Executes irg_walk(end, pre, post, env) for all irgraphs in irprog.
+   Sets current_ir_graph properly for each walk.  Conserves current
+   current_ir_graph. */
+void all_irg_walk(irg_walk_func *pre, irg_walk_func *post, void *env) {
+  int i;
+  ir_graph *irg, *rem;
+
+  rem = current_ir_graph;
+
+  for (i = 0; i < get_irp_n_irgs(); i++) {
+    irg = get_irp_irg(i);
+    current_ir_graph = irg;
+    irg_walk(get_irg_end(irg), pre, post, env);
+  }
+  current_ir_graph = rem;
+}
+
+/***************************************************************************/
+
+/* Returns current_ir_graph and sets it to the irg of predecessor index
+   of node n. */
+static INLINE ir_graph *
+switch_irg (ir_node *n, int index) {
+  ir_graph *old_current = current_ir_graph;
+
+  if (interprocedural_view) {
+    /* Only Filter and Block nodes can have predecessors in other graphs. */
+    if (get_irn_op(n) == op_Filter)
+      n = get_nodes_block(n);
+    if (get_irn_op(n) == op_Block) {
+      ir_node *cfop = skip_Proj(get_Block_cfgpred(n, index));
+      if (is_ip_cfop(cfop)) {
+    current_ir_graph = get_irn_irg(cfop);
+      }
+    }
+  }
+
+  return old_current;
+}
+
+static void
+cg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
 {
+  int i;
+  ir_graph *rem = NULL;
   assert(node);
-  inc_irg_visited (current_ir_graph);
-  irg_walk_2(node, pre, post, env);
+
+  if (get_irn_visited(node) < get_irg_visited(current_ir_graph)) {
+    set_irn_visited(node, get_irg_visited(current_ir_graph));
+
+    if (pre) pre(node, env);
+
+    if (is_no_Block(node))
+      cg_walk_2(get_nodes_block(node), pre, post, env);
+    for (i = get_irn_arity(node) - 1; i >= 0; --i) {
+      rem = switch_irg(node, i);  /* @@@ AS: Is this wrong? We do have to
+                                             switch to the irg of the predecessor, don't we? */
+      cg_walk_2(get_irn_n(node, i), pre, post, env);
+      current_ir_graph = rem;
+    }
+
+    if (post) post(node, env);
+  }
   return;
 }
 
+
+/* Walks all irgs in interprocedural view.  Visits each node only once. */
+void cg_walk(irg_walk_func *pre, irg_walk_func *post, void *env) {
+  int i;
+  ir_graph *rem = current_ir_graph;
+  int rem_view = interprocedural_view;
+
+  interprocedural_view = true;
+
+  inc_max_irg_visited();
+  /* Fix all irg_visited flags */
+  for (i = 0; i < get_irp_n_irgs(); i++)
+    set_irg_visited(get_irp_irg(i), get_max_irg_visited());
+
+  /* Walk starting at unreachable procedures. Only these
+   * have End blocks visible in interprocedural view. */
+  for (i = 0; i < get_irp_n_irgs(); i++) {
+    ir_node *sb;
+    current_ir_graph = get_irp_irg(i);
+
+    sb = get_irg_start_block(current_ir_graph);
+
+    if ((get_Block_n_cfgpreds(sb) > 1) ||
+    (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue;
+
+    cg_walk_2(get_irg_end(current_ir_graph), pre, post, env);
+  }
+
+  /* Check whether we walked all procedures: there could be procedures
+     with cyclic calls but no call from the outside. */
+  for (i = 0; i < get_irp_n_irgs(); i++) {
+    ir_node *sb;
+    current_ir_graph = get_irp_irg(i);
+
+    /* Test start block: if inner procedure end and end block are not
+     * visible and therefore not marked. */
+    sb = get_irg_start_block(current_ir_graph);
+    if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) {
+      cg_walk_2(sb, pre, post, env);
+    }
+  }
+
+  /* Walk all endless loops in inner procedures.
+   * We recognize an inner procedure if the End node is not visited. */
+  for (i = 0; i < get_irp_n_irgs(); i++) {
+    ir_node *e;
+    current_ir_graph = get_irp_irg(i);
+    e = get_irg_end(current_ir_graph);
+    if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) {
+      int j;
+      /* Don't visit the End node. */
+      for (j = 0; j < get_End_n_keepalives(e); j++)
+    cg_walk_2(get_End_keepalive(e, j), pre, post, env);
+    }
+  }
+
+  interprocedural_view = rem_view;
+  current_ir_graph = rem;
+}
+
+
 /***************************************************************************/
-void irg_block_walk_2(ir_node *node, void (pre)(ir_node*, void*),
-		      void (post)(ir_node*, void*), void *env)
+
+/* Walks back from n until it finds a real cf op. */
+static ir_node *get_cf_op(ir_node *n) {
+  ir_node *pred;
+
+  n = skip_nop(n);
+  n = skip_Tuple(n);
+  pred = skip_Proj(n);
+  if (!(is_cfop(pred) || is_fragile_op(pred) ||
+    (get_irn_op(pred) == op_Bad)))
+    n = get_cf_op(n);
+
+  return skip_Proj(n);
+}
+
+static void irg_block_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 {
   int i;
 
-  assert(get_irn_opcode(node) == iro_Block);
+  if(get_Block_block_visited(node) < get_irg_block_visited(current_ir_graph)) {
+    set_Block_block_visited(node, get_irg_block_visited(current_ir_graph));
 
-  if(get_Block_block_visit(node) < get_irg_block_visited(current_ir_graph)) {
-    set_Block_block_visit(node, get_irg_block_visited(current_ir_graph));
-
-    if(pre)
-      pre(node, env);
+    if(pre) pre(node, env);
 
     for(i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
-
       /* find the corresponding predecessor block. */
-      ir_node *pred = skip_Proj(get_Block_cfgpred(node, i));
-      /* GL: I'm not sure whether this assert must go through.  There
-         could be Id chains?? */
-      assert(is_cfop(pred) || is_fragile_op(pred));
-      pred = get_nodes_Block(pred);
-      assert(get_irn_opcode(pred) == iro_Block);
-
-      /* recursion */
-      irg_block_walk_2(pred, pre, post, env);
+      ir_node *pred = get_cf_op(get_Block_cfgpred(node, i));
+      pred = get_nodes_block(pred);
+      if(get_irn_opcode(pred) == iro_Block) {
+    /* recursion */
+    irg_block_walk_2(pred, pre, post, env);
+      }
+      else {
+    assert(get_irn_opcode(pred) == iro_Bad);
+      }
     }
 
-    if(post)
-      post(node, env);
+    if(post) post(node, env);
   }
   return;
 }
@@ -85,14 +414,332 @@ void irg_block_walk_2(ir_node *node, void (pre)(ir_node*, void*),
 
 /* walks only over Block nodes in the graph.  Has it's own visited
    flag, so that it can be interleaved with the other walker.         */
-void irg_block_walk(ir_node *node,
-		    void (pre)(ir_node*, void*), void (post)(ir_node*, void*),
-		    void *env)
+void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 {
+  ir_node *block, *pred;
+  int i;
+
+  stat_irg_block_walk(current_ir_graph, node, (void *)pre, (void *)post);
+
   assert(node);
+  assert(!interprocedural_view);   /* interprocedural_view not implemented, because it
+                    * interleaves with irg_walk */
   inc_irg_block_visited(current_ir_graph);
-  if (is_no_Block(node)) node = get_nodes_Block(node);
-  assert(get_irn_opcode(node)  == iro_Block);
-  irg_block_walk_2(node, pre, post, env);
+  if (is_no_Block(node)) block = get_nodes_block(node); else block = node;
+  assert(get_irn_opcode(block)  == iro_Block);
+  irg_block_walk_2(block, pre, post, env);
+  /* keepalive: the endless loops ... */
+  if (get_irn_op(node) == op_End) {
+    int arity = get_irn_arity(node);
+    for (i = 0; i < arity; i++) {
+      pred = get_irn_n(node, i);
+      if (get_irn_op(pred) == op_Block)
+        irg_block_walk_2(pred, pre, post, env);
+    }
+  }
+
   return;
 }
+
+
+void irg_block_walk_graph(ir_graph *irg, irg_walk_func *pre,
+              irg_walk_func *post, void *env) {
+  ir_graph * rem = current_ir_graph;
+  current_ir_graph = irg;
+  irg_block_walk(get_irg_end(irg), pre, post, env);
+  current_ir_graph = rem;
+}
+
+/********************************************************************/
+
+typedef struct walk_env {
+  irg_walk_func *pre;
+  irg_walk_func *post;
+  void *env;
+} walk_env;
+
+/* Walk to all constant expressions in this entity. */
+static void walk_entity(entity *ent, void *env)
+{
+  walk_env *my_env = (walk_env *)env;
+
+  if (get_entity_variability(ent) != variability_uninitialized) {
+    if (is_atomic_entity(ent)) {
+      irg_walk(get_atomic_ent_value(ent), my_env->pre, my_env->post, my_env->env);
+    }
+    else {
+      int i, n = get_compound_ent_n_values(ent);
+
+      for (i = 0; i < n; i++)
+        irg_walk(get_compound_ent_value(ent, i), my_env->pre, my_env->post, my_env->env);
+    }
+  }
+}
+
+/* Walks over all code in const_code_irg. */
+void walk_const_code(irg_walk_func *pre, irg_walk_func *post, void *env) {
+  int i, j;
+  walk_env my_env;
+
+  ir_graph *rem = current_ir_graph;
+  current_ir_graph = get_const_code_irg();
+  inc_irg_visited(current_ir_graph);
+
+  my_env.pre = pre;
+  my_env.post = post;
+  my_env.env = env;
+
+  /* Walk all types that can contain constant entities.  */
+  walk_types_entities(get_glob_type(), &walk_entity, &my_env);
+  for (i = 0; i < get_irp_n_types(); i++)
+    walk_types_entities(get_irp_type(i), &walk_entity, &my_env);
+  for (i = 0; i < get_irp_n_irgs(); i++)
+    walk_types_entities(get_irg_frame_type(get_irp_irg(i)), &walk_entity, &my_env);
+
+  /* Walk constant array bounds. */
+  for (i = 0; i < get_irp_n_types(); i++) {
+    type *tp = get_irp_type(i);
+    if (is_array_type(tp)) {
+      for (j = 0; j < get_array_n_dimensions(tp); j++) {
+    ir_node *n;
+    n = get_array_lower_bound(tp, j);
+    if (n) irg_walk(n, pre, post, env);
+    n = get_array_upper_bound(tp, j);
+    if (n) irg_walk(n, pre, post, env);
+      }
+    }
+  }
+
+  current_ir_graph = rem;
+}
+
+
+/********************************************************************/
+/** Walking support for interprocedural analysis                   **/
+/**                                                                **/
+/** @@@ Don't use, not operational yet, doesn't grok recursions!!  **/
+/** @@@ Header for irgwalk.h, here until it works. **/
+/**                                                                **/
+/** Interprocedural walking should not walk all predecessors of    **/
+/** all nodes.  When leaving a procedure the walker should only    **/
+/** follow the edge corresponding to the most recent entry of the  **/
+/** procedure.  The following functions use an internal stack to   **/
+/** remember the current call site of a procedure.                 **/
+/** They also set current_ir_graph correctly.                      **/
+/**                                                                **/
+/** Usage example:                                                 **/
+/**                                                                **/
+/** void init_ip_walk ();                                          **/
+/** work_on_graph(some_end_node);                                  **/
+/** void finish_ip_walk();                                         **/
+/**                                                                **/
+/** work_on_graph(ir_node *n) {                                    **/
+/**   for (i = 0; i < get_irn_arity(n); i++) {                     **/
+/**     if (...) continue;                                         **/
+/**     ir_node *m = get_irn_ip_pred(n, i);                        **/
+/**     if !m continue;                                            **/
+/**     work_on_graph(m);                                          **/
+/**     return_recur(n, i);                                        **/
+/**   }                                                            **/
+/** }                                                              **/
+/********************************************************************/
+
+/* Call for i in {0|-1 ... get_irn_arity(n)}.
+   If n is a conventional node returns the same node as get_irn_n(n, i).
+   If the predecessors of n are in the callee of the procedure n belongs
+   to, returns get_irn_n(n, i) if this node is in the callee on the top
+   of the stack, else returns NULL.
+   If the predecessors of n are in a procedure called by the procedure n
+   belongs to pushes the caller on the caller stack in the callee.
+   Sets current_ir_graph to the graph the node returned is in. */
+ir_node *get_irn_ip_pred(ir_node *n, int pos);
+
+/* If get_irn_ip_pred() returned a node (not NULL) this must be
+   called to clear up the stacks.
+   Sets current_ir_graph to the graph n is in. */
+void return_recur(ir_node *n, int pos);
+
+
+/********************************************************************/
+/** Walking support for interprocedural analysis                   **/
+/********************************************************************/
+
+#define MIN_STACK_SIZE 40
+
+typedef struct callsite_stack {
+  int tos;
+  ir_node **s;
+} callsite_stack;
+
+/* Access the stack in the irg **************************************/
+
+static INLINE void
+set_irg_callsite_stack(ir_graph *g, callsite_stack *s) {
+  set_irg_link(g, s);
+}
+
+static INLINE callsite_stack *
+get_irg_callsite_stack(ir_graph *g) {
+  return (callsite_stack *) get_irg_link(g);
+}
+
+/* A stack of callsites *********************************************/
+
+/* @@@ eventually change the implementation so the new_ only sets the field
+   to NULL, and the stack is only allocated if used.  Saves Memory! */
+static INLINE callsite_stack *
+new_callsite_stack(ir_graph *g) {
+  callsite_stack *res = (callsite_stack *)malloc(sizeof(callsite_stack));
+  res->tos = 0;
+  res->s = NEW_ARR_F (ir_node *, MIN_STACK_SIZE);
+  set_irg_callsite_stack(g, res);
+  return(res);
+}
+
+static INLINE void
+free_callsite_stack(ir_graph *g) {
+  callsite_stack *s = get_irg_callsite_stack(g);
+  DEL_ARR_F(s->s);
+  free(s);
+}
+
+static INLINE void
+push_callsite(ir_graph *callee, ir_node *callsite) {
+  callsite_stack *s = get_irg_callsite_stack(callee);
+  if (s->tos == ARR_LEN(s->s)) {
+    int nlen = ARR_LEN (s->s) * 2;
+    ARR_RESIZE (ir_node *, s->s, nlen);
+  }
+  s->s[s->tos] = callsite;
+  s->tos++;
+}
+
+static INLINE ir_node *
+get_top_of_callsite_stack(ir_graph *callee) {
+  callsite_stack *s = get_irg_callsite_stack(callee);
+  return (s->s[s->tos-1]);
+}
+
+static INLINE
+ir_node * pop_callsite(ir_graph *callee) {
+  callsite_stack *s = get_irg_callsite_stack(callee);
+  s->tos--;
+  return (s->s[s->tos]);
+}
+
+
+/* Initialization routines ******************************************/
+
+void init_ip_walk (void) {
+  int i;
+  for (i = 0; i < get_irp_n_irgs(); i++)
+    new_callsite_stack(get_irp_irg(i));
+}
+
+void finish_ip_walk(void) {
+  int i;
+  for (i = 0; i < get_irp_n_irgs(); i++)
+    free_callsite_stack(get_irp_irg(i));
+  set_irg_link(get_irp_irg(i), NULL);
+}
+
+/* walker routines **************************************************/
+
+/* cf_pred is End* */
+static INLINE void
+enter_procedure(ir_node *block, ir_node *cf_pred, int pos) {
+  ir_node *callbegin;
+  ir_graph *irg = get_irn_irg(cf_pred);
+
+  assert(interprocedural_view);
+
+  interprocedural_view = 0;
+  callbegin = skip_Proj(get_irn_n(block, 0));
+  assert(get_irn_op(callbegin) == op_CallBegin);
+  interprocedural_view = 1;
+
+  push_callsite(irg, callbegin);
+  current_ir_graph = irg;
+}
+
+/* cf_pred is CallBegin */
+static INLINE bool
+leave_procedure(ir_node *block, ir_node *cf_pred, int pos) {
+  ir_node *tos = get_top_of_callsite_stack(current_ir_graph);
+
+  assert(get_irn_op(cf_pred) == op_CallBegin);
+
+  if (tos == cf_pred) {
+    /* We entered this procedure by the call pred pos refers to. */
+    pop_callsite(current_ir_graph);
+    current_ir_graph = get_CallBegin_irg(cf_pred);
+    return true;
+  } else {
+    /* We won't walk. */
+    return false;
+  }
+}
+
+ir_node *get_irn_ip_pred(ir_node *n, int pos) {
+
+  if (interprocedural_view) {
+
+    /* Find the cf_pred refering to pos. */
+    ir_node *block = n;
+    ir_node *cf_pred;
+    if (get_irn_opcode(n) == iro_Filter) block = get_nodes_block(n);
+    cf_pred = skip_Proj(get_irn_n(block, pos));
+
+    /* Check whether we enter or leave a procedure and act according. */
+    if ((get_irn_op(cf_pred) == op_EndReg) ||
+    (get_irn_op(cf_pred) == op_EndExcept))
+      enter_procedure(block, cf_pred, pos);
+    if (get_irn_op(cf_pred) == op_CallBegin)
+      if (!leave_procedure(block, cf_pred, pos)) return NULL;
+  }
+
+  return get_irn_n(n, pos);
+}
+
+static INLINE void
+re_enter_procedure(ir_node *block, ir_node *cf_pred, int pos) {
+  ir_node *callbegin = pop_callsite(current_ir_graph);
+  assert(interprocedural_view);
+  current_ir_graph = get_CallBegin_irg(callbegin);
+}
+
+static INLINE void
+re_leave_procedure(ir_node *block, ir_node *cf_pred, int pos) {
+  ir_node *proj;
+  ir_graph *callee;
+
+  assert(get_irn_op(cf_pred) == op_CallBegin);
+
+  /* Find the irg block is in. */
+  proj = get_Block_cg_cfgpred(block, pos);
+  assert(is_Proj(proj));
+  callee = get_entity_irg(get_Call_callee(get_CallBegin_call(cf_pred),
+                      get_Proj_proj(proj)));
+  current_ir_graph = callee;
+  push_callsite(callee, cf_pred);
+}
+
+void
+return_recur(ir_node *n, int pos) {
+  ir_node *block;
+  ir_node *cf_pred;
+
+  if (!interprocedural_view) return;
+
+  /* Find the cf_pred refering to pos. */
+  block = n;
+  if (get_irn_opcode(n) == iro_Filter) block = get_nodes_block(n);
+  cf_pred = skip_Proj(get_irn_n(block, pos));
+
+  /* Check whether we re_enter or re_leave a procedure and act according. */
+  if ((get_irn_op(cf_pred) == op_EndReg) ||
+      (get_irn_op(cf_pred) == op_EndExcept))
+    re_enter_procedure(block, cf_pred, pos);
+  if (get_irn_op(cf_pred) == op_CallBegin)
+    re_leave_procedure(block, cf_pred, pos);
+}