1/*
2 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "memory/allocation.inline.hpp"
27#include "opto/callnode.hpp"
28#include "opto/cfgnode.hpp"
29#include "opto/phaseX.hpp"
30#include "opto/regmask.hpp"
31#include "opto/rootnode.hpp"
32#include "opto/subnode.hpp"
33#include "opto/type.hpp"
34
35//------------------------------Ideal------------------------------------------
36// Remove dead inputs
37Node *RootNode::Ideal(PhaseGVN *phase, bool can_reshape) {
38  bool modified = false;
39  for( uint i = 1; i < req(); i++ ) { // For all inputs
40    // Check for and remove dead inputs
41    if( phase->type(in(i)) == Type::TOP ) {
42      del_req(i--);             // Delete TOP inputs
43      modified = true;
44    }
45  }
46
47  // I used to do tail-splitting in the Ideal graph here, but it does not
48  // work.  The tail-splitting forces values live into the Return to be
49  // ready at a point which dominates the split returns.  This forces Stores
50  // to be hoisted high.  The "proper" fix would be to split Stores down
51  // each path, but this makes the split unprofitable.  If we want to do this
52  // optimization, it needs to be done after allocation so we can count all
53  // the instructions needing to be cloned in the cost metric.
54
55  // There used to be a spoof here for caffeine marks which completely
56  // eliminated very simple self-recursion recursions, but it's not worth it.
57  // Deep inlining of self-calls gets nearly all of the same benefits.
58  // If we want to get the rest of the win later, we should pattern match
59  // simple recursive call trees to closed-form solutions.
60
61  return modified ? this : NULL;
62}
63
64//=============================================================================
65HaltNode::HaltNode( Node *ctrl, Node *frameptr ) : Node(TypeFunc::Parms) {
66  Node* top = Compile::current()->top();
67  init_req(TypeFunc::Control,  ctrl        );
68  init_req(TypeFunc::I_O,      top);
69  init_req(TypeFunc::Memory,   top);
70  init_req(TypeFunc::FramePtr, frameptr    );
71  init_req(TypeFunc::ReturnAdr,top);
72}
73
74const Type *HaltNode::bottom_type() const { return Type::BOTTOM; }
75
76//------------------------------Ideal------------------------------------------
77Node *HaltNode::Ideal(PhaseGVN *phase, bool can_reshape) {
78  return remove_dead_region(phase, can_reshape) ? this : NULL;
79}
80
81//------------------------------Value------------------------------------------
82const Type* HaltNode::Value(PhaseGVN* phase) const {
83  return ( phase->type(in(TypeFunc::Control)) == Type::TOP)
84    ? Type::TOP
85    : Type::BOTTOM;
86}
87
88const RegMask &HaltNode::out_RegMask() const {
89  return RegMask::Empty;
90}
91
92#ifndef PRODUCT
93//-----------------------------related-----------------------------------------
94// Include all control inputs in the related set, and also the input data
95// boundary. In compact mode, include all inputs till level 2. Also include
96// all outputs at level 1.
97void HaltNode::related(GrowableArray<Node*> *in_rel, GrowableArray<Node*> *out_rel, bool compact) const {
98  if (compact) {
99    this->collect_nodes(in_rel, 2, false, false);
100  } else {
101    this->collect_nodes_in_all_ctrl(in_rel, true);
102  }
103  this->collect_nodes(out_rel, -1, false, false);
104}
105#endif
106