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comparison src/share/vm/opto/locknode.cpp @ 4777:e9a5e0a812c8

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7125896: Eliminate nested locks Summary: Nested locks elimination done before lock nodes expansion by looking for outer locks of the same object. Reviewed-by: never, twisti
author kvn
date Sat, 07 Jan 2012 13:26:43 -0800
parents f95d63e2154a
children 35acf8f0a2e4
comparison
equal deleted inserted replaced
4776:5da7201222d5 4777:e9a5e0a812c8
47 _inmask.Insert(reg); 47 _inmask.Insert(reg);
48 } 48 }
49 49
50 //-----------------------------hash-------------------------------------------- 50 //-----------------------------hash--------------------------------------------
51 uint BoxLockNode::hash() const { 51 uint BoxLockNode::hash() const {
52 if (EliminateNestedLocks)
53 return NO_HASH; // Each locked region has own BoxLock node
52 return Node::hash() + _slot + (_is_eliminated ? Compile::current()->fixed_slots() : 0); 54 return Node::hash() + _slot + (_is_eliminated ? Compile::current()->fixed_slots() : 0);
53 } 55 }
54 56
55 //------------------------------cmp-------------------------------------------- 57 //------------------------------cmp--------------------------------------------
56 uint BoxLockNode::cmp( const Node &n ) const { 58 uint BoxLockNode::cmp( const Node &n ) const {
59 if (EliminateNestedLocks)
60 return (&n == this); // Always fail except on self
57 const BoxLockNode &bn = (const BoxLockNode &)n; 61 const BoxLockNode &bn = (const BoxLockNode &)n;
58 return bn._slot == _slot && bn._is_eliminated == _is_eliminated; 62 return bn._slot == _slot && bn._is_eliminated == _is_eliminated;
59 } 63 }
60 64
61 OptoReg::Name BoxLockNode::stack_slot(Node* box_node) { 65 BoxLockNode* BoxLockNode::box_node(Node* box) {
62 // Chase down the BoxNode 66 // Chase down the BoxNode
63 while (!box_node->is_BoxLock()) { 67 while (!box->is_BoxLock()) {
64 // if (box_node->is_SpillCopy()) { 68 // if (box_node->is_SpillCopy()) {
65 // Node *m = box_node->in(1); 69 // Node *m = box_node->in(1);
66 // if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_StoreP) { 70 // if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_StoreP) {
67 // box_node = m->in(m->as_Mach()->operand_index(2)); 71 // box_node = m->in(m->as_Mach()->operand_index(2));
68 // continue; 72 // continue;
69 // } 73 // }
70 // } 74 // }
71 assert(box_node->is_SpillCopy() || box_node->is_Phi(), "Bad spill of Lock."); 75 assert(box->is_SpillCopy() || box->is_Phi(), "Bad spill of Lock.");
72 box_node = box_node->in(1); 76 // Only BoxLock nodes with the same stack slot are merged.
73 } 77 // So it is enough to trace one path to find the slot value.
74 return box_node->in_RegMask(0).find_first_elem(); 78 box = box->in(1);
79 }
80 return box->as_BoxLock();
81 }
82
83 OptoReg::Name BoxLockNode::reg(Node* box) {
84 return box_node(box)->in_RegMask(0).find_first_elem();
85 }
86
87 bool BoxLockNode::same_slot(Node* box1, Node* box2) {
88 return box_node(box1)->_slot == box_node(box2)->_slot;
89 }
90
91 // Is BoxLock node used for one simple lock region (same box and obj)?
92 bool BoxLockNode::is_simple_lock_region(LockNode** unique_lock, Node* obj) {
93 LockNode* lock = NULL;
94 bool has_one_lock = false;
95 for (uint i = 0; i < this->outcnt(); i++) {
96 Node* n = this->raw_out(i);
97 if (n->is_Phi())
98 return false; // Merged regions
99 if (n->is_AbstractLock()) {
100 AbstractLockNode* alock = n->as_AbstractLock();
101 // Check lock's box since box could be referenced by Lock's debug info.
102 if (alock->box_node() == this) {
103 if (alock->obj_node() == obj) {
104 if ((unique_lock != NULL) && alock->is_Lock()) {
105 if (lock == NULL) {
106 lock = alock->as_Lock();
107 has_one_lock = true;
108 } else if (lock != alock->as_Lock()) {
109 has_one_lock = false;
110 }
111 }
112 } else {
113 return false; // Different objects
114 }
115 }
116 }
117 }
118 #ifdef ASSERT
119 // Verify that FastLock and Safepoint reference only this lock region.
120 for (uint i = 0; i < this->outcnt(); i++) {
121 Node* n = this->raw_out(i);
122 if (n->is_FastLock()) {
123 FastLockNode* flock = n->as_FastLock();
124 assert((flock->box_node() == this) && (flock->obj_node() == obj),"");
125 }
126 if (n->is_SafePoint() && n->as_SafePoint()->jvms()) {
127 SafePointNode* sfn = n->as_SafePoint();
128 JVMState* youngest_jvms = sfn->jvms();
129 int max_depth = youngest_jvms->depth();
130 for (int depth = 1; depth <= max_depth; depth++) {
131 JVMState* jvms = youngest_jvms->of_depth(depth);
132 int num_mon = jvms->nof_monitors();
133 // Loop over monitors
134 for (int idx = 0; idx < num_mon; idx++) {
135 Node* obj_node = sfn->monitor_obj(jvms, idx);
136 Node* box_node = sfn->monitor_box(jvms, idx);
137 if (box_node == this) {
138 assert(obj_node == obj,"");
139 }
140 }
141 }
142 }
143 }
144 #endif
145 if (unique_lock != NULL && has_one_lock) {
146 *unique_lock = lock;
147 }
148 return true;
75 } 149 }
76 150
77 //============================================================================= 151 //=============================================================================
78 //-----------------------------hash-------------------------------------------- 152 //-----------------------------hash--------------------------------------------
79 uint FastLockNode::hash() const { return NO_HASH; } 153 uint FastLockNode::hash() const { return NO_HASH; }