src/hotspot/share/opto/replacednodes.cpp
changeset 47216 71c04702a3d5
parent 43963 6845bb645be5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/opto/replacednodes.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "memory/resourceArea.hpp"
+#include "opto/cfgnode.hpp"
+#include "opto/phaseX.hpp"
+#include "opto/replacednodes.hpp"
+
+void ReplacedNodes::allocate_if_necessary() {
+  if (_replaced_nodes == NULL) {
+    _replaced_nodes = new GrowableArray<ReplacedNode>();
+  }
+}
+
+bool ReplacedNodes::is_empty() const {
+  return _replaced_nodes == NULL || _replaced_nodes->length() == 0;
+}
+
+bool ReplacedNodes::has_node(const ReplacedNode& r) const {
+  return _replaced_nodes->find(r) != -1;
+}
+
+bool ReplacedNodes::has_target_node(Node* n) const {
+  for (int i = 0; i < _replaced_nodes->length(); i++) {
+    if (_replaced_nodes->at(i).improved() == n) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// Record replaced node if not seen before
+void ReplacedNodes::record(Node* initial, Node* improved) {
+  allocate_if_necessary();
+  ReplacedNode r(initial, improved);
+  if (!has_node(r)) {
+    _replaced_nodes->push(r);
+  }
+}
+
+// Copy replaced nodes from one map to another. idx is used to
+// identify nodes that are too new to be of interest in the target
+// node list.
+void ReplacedNodes::transfer_from(const ReplacedNodes& other, uint idx) {
+  if (other.is_empty()) {
+    return;
+  }
+  allocate_if_necessary();
+  for (int i = 0; i < other._replaced_nodes->length(); i++) {
+    ReplacedNode replaced = other._replaced_nodes->at(i);
+    // Only transfer the nodes that can actually be useful
+    if (!has_node(replaced) && (replaced.initial()->_idx < idx || has_target_node(replaced.initial()))) {
+      _replaced_nodes->push(replaced);
+    }
+  }
+}
+
+void ReplacedNodes::clone() {
+  if (_replaced_nodes != NULL) {
+    GrowableArray<ReplacedNode>* replaced_nodes_clone = new GrowableArray<ReplacedNode>();
+    replaced_nodes_clone->appendAll(_replaced_nodes);
+    _replaced_nodes = replaced_nodes_clone;
+  }
+}
+
+void ReplacedNodes::reset() {
+  if (_replaced_nodes != NULL) {
+    _replaced_nodes->clear();
+  }
+}
+
+// Perfom node replacement (used when returning to caller)
+void ReplacedNodes::apply(Node* n, uint idx) {
+  if (is_empty()) {
+    return;
+  }
+  for (int i = 0; i < _replaced_nodes->length(); i++) {
+    ReplacedNode replaced = _replaced_nodes->at(i);
+    // Only apply if improved node was created in a callee to avoid
+    // issues with irreducible loops in the caller
+    if (replaced.improved()->_idx >= idx) {
+      n->replace_edge(replaced.initial(), replaced.improved());
+    }
+  }
+}
+
+static void enqueue_use(Node* n, Node* use, Unique_Node_List& work) {
+  if (use->is_Phi()) {
+    Node* r = use->in(0);
+    assert(r->is_Region(), "Phi should have Region");
+    for (uint i = 1; i < use->req(); i++) {
+      if (use->in(i) == n) {
+        work.push(r->in(i));
+      }
+    }
+  } else {
+    work.push(use);
+  }
+}
+
+// Perfom node replacement following late inlining
+void ReplacedNodes::apply(Compile* C, Node* ctl) {
+  // ctl is the control on exit of the method that was late inlined
+  if (is_empty()) {
+    return;
+  }
+  for (int i = 0; i < _replaced_nodes->length(); i++) {
+    ReplacedNode replaced = _replaced_nodes->at(i);
+    Node* initial = replaced.initial();
+    Node* improved = replaced.improved();
+    assert (ctl != NULL && !ctl->is_top(), "replaced node should have actual control");
+
+    ResourceMark rm;
+    Unique_Node_List work;
+    // Go over all the uses of the node that is considered for replacement...
+    for (DUIterator j = initial->outs(); initial->has_out(j); j++) {
+      Node* use = initial->out(j);
+
+      if (use == improved || use->outcnt() == 0) {
+        continue;
+      }
+      work.clear();
+      enqueue_use(initial, use, work);
+      bool replace = true;
+      // Check that this use is dominated by ctl. Go ahead with the
+      // replacement if it is.
+      while (work.size() != 0 && replace) {
+        Node* n = work.pop();
+        if (use->outcnt() == 0) {
+          continue;
+        }
+        if (n->is_CFG() || (n->in(0) != NULL && !n->in(0)->is_top())) {
+          int depth = 0;
+          Node *m = n;
+          if (!n->is_CFG()) {
+            n = n->in(0);
+          }
+          assert(n->is_CFG(), "should be CFG now");
+          while(n != ctl) {
+            n = IfNode::up_one_dom(n);
+            depth++;
+            // limit search depth
+            if (depth >= 100 || n == NULL) {
+              replace = false;
+              break;
+            }
+          }
+        } else {
+          for (DUIterator k = n->outs(); n->has_out(k); k++) {
+            enqueue_use(n, n->out(k), work);
+          }
+        }
+      }
+      if (replace) {
+        bool is_in_table = C->initial_gvn()->hash_delete(use);
+        int replaced = use->replace_edge(initial, improved);
+        if (is_in_table) {
+          C->initial_gvn()->hash_find_insert(use);
+        }
+        C->record_for_igvn(use);
+
+        assert(replaced > 0, "inconsistent");
+        --j;
+      }
+    }
+  }
+}
+
+void ReplacedNodes::dump(outputStream *st) const {
+  if (!is_empty()) {
+    st->print("replaced nodes: ");
+    for (int i = 0; i < _replaced_nodes->length(); i++) {
+      st->print("%d->%d", _replaced_nodes->at(i).initial()->_idx, _replaced_nodes->at(i).improved()->_idx);
+      if (i < _replaced_nodes->length()-1) {
+        st->print(",");
+      }
+    }
+  }
+}
+
+// Merge 2 list of replaced node at a point where control flow paths merge
+void ReplacedNodes::merge_with(const ReplacedNodes& other) {
+  if (is_empty()) {
+    return;
+  }
+  if (other.is_empty()) {
+    reset();
+    return;
+  }
+  int shift = 0;
+  int len = _replaced_nodes->length();
+  for (int i = 0; i < len; i++) {
+    if (!other.has_node(_replaced_nodes->at(i))) {
+      shift++;
+    } else if (shift > 0) {
+      _replaced_nodes->at_put(i-shift, _replaced_nodes->at(i));
+    }
+  }
+  if (shift > 0) {
+    _replaced_nodes->trunc_to(len - shift);
+  }
+}