roland@7041: /*
roland@7041:  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
roland@7041:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
roland@7041:  *
roland@7041:  * This code is free software; you can redistribute it and/or modify it
roland@7041:  * under the terms of the GNU General Public License version 2 only, as
roland@7041:  * published by the Free Software Foundation.
roland@7041:  *
roland@7041:  * This code is distributed in the hope that it will be useful, but WITHOUT
roland@7041:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
roland@7041:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
roland@7041:  * version 2 for more details (a copy is included in the LICENSE file that
roland@7041:  * accompanied this code).
roland@7041:  *
roland@7041:  * You should have received a copy of the GNU General Public License version
roland@7041:  * 2 along with this work; if not, write to the Free Software Foundation,
roland@7041:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
roland@7041:  *
roland@7041:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
roland@7041:  * or visit www.oracle.com if you need additional information or have any
roland@7041:  * questions.
roland@7041:  *
roland@7041:  */
roland@7041: 
roland@7041: #include "precompiled.hpp"
roland@7041: #include "opto/cfgnode.hpp"
roland@7041: #include "opto/phaseX.hpp"
roland@7041: #include "opto/replacednodes.hpp"
roland@7041: 
roland@7041: void ReplacedNodes::allocate_if_necessary() {
roland@7041:   if (_replaced_nodes == NULL) {
roland@7041:     _replaced_nodes = new GrowableArray<ReplacedNode>();
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: bool ReplacedNodes::is_empty() const {
roland@7041:   return _replaced_nodes == NULL || _replaced_nodes->length() == 0;
roland@7041: }
roland@7041: 
roland@7041: bool ReplacedNodes::has_node(const ReplacedNode& r) const {
roland@7041:   return _replaced_nodes->find(r) != -1;
roland@7041: }
roland@7041: 
roland@7041: bool ReplacedNodes::has_target_node(Node* n) const {
roland@7041:   for (int i = 0; i < _replaced_nodes->length(); i++) {
roland@7041:     if (_replaced_nodes->at(i).improved() == n) {
roland@7041:       return true;
roland@7041:     }
roland@7041:   }
roland@7041:   return false;
roland@7041: }
roland@7041: 
roland@7041: // Record replaced node if not seen before
roland@7041: void ReplacedNodes::record(Node* initial, Node* improved) {
roland@7041:   allocate_if_necessary();
roland@7041:   ReplacedNode r(initial, improved);
roland@7041:   if (!has_node(r)) {
roland@7041:     _replaced_nodes->push(r);
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: // Copy replaced nodes from one map to another. idx is used to
roland@7041: // identify nodes that are too new to be of interest in the target
roland@7041: // node list.
roland@7041: void ReplacedNodes::transfer_from(const ReplacedNodes& other, uint idx) {
roland@7041:   if (other.is_empty()) {
roland@7041:     return;
roland@7041:   }
roland@7041:   allocate_if_necessary();
roland@7041:   for (int i = 0; i < other._replaced_nodes->length(); i++) {
roland@7041:     ReplacedNode replaced = other._replaced_nodes->at(i);
roland@7041:     // Only transfer the nodes that can actually be useful
roland@7041:     if (!has_node(replaced) && (replaced.initial()->_idx < idx || has_target_node(replaced.initial()))) {
roland@7041:       _replaced_nodes->push(replaced);
roland@7041:     }
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: void ReplacedNodes::clone() {
roland@7041:   if (_replaced_nodes != NULL) {
roland@7041:     GrowableArray<ReplacedNode>* replaced_nodes_clone = new GrowableArray<ReplacedNode>();
roland@7041:     replaced_nodes_clone->appendAll(_replaced_nodes);
roland@7041:     _replaced_nodes = replaced_nodes_clone;
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: void ReplacedNodes::reset() {
roland@7041:   if (_replaced_nodes != NULL) {
roland@7041:     _replaced_nodes->clear();
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: // Perfom node replacement (used when returning to caller)
roland@7041: void ReplacedNodes::apply(Node* n) {
roland@7041:   if (is_empty()) {
roland@7041:     return;
roland@7041:   }
roland@7041:   for (int i = 0; i < _replaced_nodes->length(); i++) {
roland@7041:     ReplacedNode replaced = _replaced_nodes->at(i);
roland@7041:     n->replace_edge(replaced.initial(), replaced.improved());
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: static void enqueue_use(Node* n, Node* use, Unique_Node_List& work) {
roland@7041:   if (use->is_Phi()) {
roland@7041:     Node* r = use->in(0);
roland@7041:     assert(r->is_Region(), "Phi should have Region");
roland@7041:     for (uint i = 1; i < use->req(); i++) {
roland@7041:       if (use->in(i) == n) {
roland@7041:         work.push(r->in(i));
roland@7041:       }
roland@7041:     }
roland@7041:   } else {
roland@7041:     work.push(use);
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: // Perfom node replacement following late inlining
roland@7041: void ReplacedNodes::apply(Compile* C, Node* ctl) {
roland@7041:   // ctl is the control on exit of the method that was late inlined
roland@7041:   if (is_empty()) {
roland@7041:     return;
roland@7041:   }
roland@7041:   for (int i = 0; i < _replaced_nodes->length(); i++) {
roland@7041:     ReplacedNode replaced = _replaced_nodes->at(i);
roland@7041:     Node* initial = replaced.initial();
roland@7041:     Node* improved = replaced.improved();
roland@7041:     assert (ctl != NULL && !ctl->is_top(), "replaced node should have actual control");
roland@7041: 
roland@7041:     ResourceMark rm;
roland@7041:     Unique_Node_List work;
roland@7041:     // Go over all the uses of the node that is considered for replacement...
roland@7041:     for (DUIterator j = initial->outs(); initial->has_out(j); j++) {
roland@7041:       Node* use = initial->out(j);
roland@7041: 
roland@7041:       if (use == improved || use->outcnt() == 0) {
roland@7041:         continue;
roland@7041:       }
roland@7041:       work.clear();
roland@7041:       enqueue_use(initial, use, work);
roland@7041:       bool replace = true;
roland@7041:       // Check that this use is dominated by ctl. Go ahead with the
roland@7041:       // replacement if it is.
roland@7041:       while (work.size() != 0 && replace) {
roland@7041:         Node* n = work.pop();
roland@7041:         if (use->outcnt() == 0) {
roland@7041:           continue;
roland@7041:         }
roland@7041:         if (n->is_CFG() || (n->in(0) != NULL && !n->in(0)->is_top())) {
roland@7041:           int depth = 0;
roland@7041:           Node *m = n;
roland@7041:           if (!n->is_CFG()) {
roland@7041:             n = n->in(0);
roland@7041:           }
roland@7041:           assert(n->is_CFG(), "should be CFG now");
roland@7041:           while(n != ctl) {
roland@7041:             n = IfNode::up_one_dom(n);
roland@7041:             depth++;
roland@7041:             // limit search depth
roland@7041:             if (depth >= 100 || n == NULL) {
roland@7041:               replace = false;
roland@7041:               break;
roland@7041:             }
roland@7041:           }
roland@7041:         } else {
roland@7041:           for (DUIterator k = n->outs(); n->has_out(k); k++) {
roland@7041:             enqueue_use(n, n->out(k), work);
roland@7041:           }
roland@7041:         }
roland@7041:       }
roland@7041:       if (replace) {
roland@7041:         bool is_in_table = C->initial_gvn()->hash_delete(use);
roland@7041:         int replaced = use->replace_edge(initial, improved);
roland@7041:         if (is_in_table) {
roland@7041:           C->initial_gvn()->hash_find_insert(use);
roland@7041:         }
roland@7041:         C->record_for_igvn(use);
roland@7041: 
roland@7041:         assert(replaced > 0, "inconsistent");
roland@7041:         --j;
roland@7041:       }
roland@7041:     }
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: void ReplacedNodes::dump(outputStream *st) const {
roland@7041:   if (!is_empty()) {
roland@7041:     tty->print("replaced nodes: ");
roland@7041:     for (int i = 0; i < _replaced_nodes->length(); i++) {
roland@7041:       tty->print("%d->%d", _replaced_nodes->at(i).initial()->_idx, _replaced_nodes->at(i).improved()->_idx);
roland@7041:       if (i < _replaced_nodes->length()-1) {
roland@7041:         tty->print(",");
roland@7041:       }
roland@7041:     }
roland@7041:   }
roland@7041: }
roland@7041: 
roland@7041: // Merge 2 list of replaced node at a point where control flow paths merge
roland@7041: void ReplacedNodes::merge_with(const ReplacedNodes& other) {
roland@7041:   if (is_empty()) {
roland@7041:     return;
roland@7041:   }
roland@7041:   if (other.is_empty()) {
roland@7041:     reset();
roland@7041:     return;
roland@7041:   }
roland@7041:   int shift = 0;
roland@7041:   int len = _replaced_nodes->length();
roland@7041:   for (int i = 0; i < len; i++) {
roland@7041:     if (!other.has_node(_replaced_nodes->at(i))) {
roland@7041:       shift++;
roland@7041:     } else if (shift > 0) {
roland@7041:       _replaced_nodes->at_put(i-shift, _replaced_nodes->at(i));
roland@7041:     }
roland@7041:   }
roland@7041:   if (shift > 0) {
roland@7041:     _replaced_nodes->trunc_to(len - shift);
roland@7041:   }
roland@7041: }