Mercurial > hg > truffle
diff src/share/vm/opto/locknode.cpp @ 4777:e9a5e0a812c8
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 |
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--- a/src/share/vm/opto/locknode.cpp Sat Jan 07 10:39:23 2012 -0800 +++ b/src/share/vm/opto/locknode.cpp Sat Jan 07 13:26:43 2012 -0800 @@ -49,18 +49,22 @@ //-----------------------------hash-------------------------------------------- uint BoxLockNode::hash() const { + if (EliminateNestedLocks) + return NO_HASH; // Each locked region has own BoxLock node return Node::hash() + _slot + (_is_eliminated ? Compile::current()->fixed_slots() : 0); } //------------------------------cmp-------------------------------------------- uint BoxLockNode::cmp( const Node &n ) const { + if (EliminateNestedLocks) + return (&n == this); // Always fail except on self const BoxLockNode &bn = (const BoxLockNode &)n; return bn._slot == _slot && bn._is_eliminated == _is_eliminated; } -OptoReg::Name BoxLockNode::stack_slot(Node* box_node) { +BoxLockNode* BoxLockNode::box_node(Node* box) { // Chase down the BoxNode - while (!box_node->is_BoxLock()) { + while (!box->is_BoxLock()) { // if (box_node->is_SpillCopy()) { // Node *m = box_node->in(1); // if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_StoreP) { @@ -68,10 +72,80 @@ // continue; // } // } - assert(box_node->is_SpillCopy() || box_node->is_Phi(), "Bad spill of Lock."); - box_node = box_node->in(1); + assert(box->is_SpillCopy() || box->is_Phi(), "Bad spill of Lock."); + // Only BoxLock nodes with the same stack slot are merged. + // So it is enough to trace one path to find the slot value. + box = box->in(1); } - return box_node->in_RegMask(0).find_first_elem(); + return box->as_BoxLock(); +} + +OptoReg::Name BoxLockNode::reg(Node* box) { + return box_node(box)->in_RegMask(0).find_first_elem(); +} + +bool BoxLockNode::same_slot(Node* box1, Node* box2) { + return box_node(box1)->_slot == box_node(box2)->_slot; +} + +// Is BoxLock node used for one simple lock region (same box and obj)? +bool BoxLockNode::is_simple_lock_region(LockNode** unique_lock, Node* obj) { + LockNode* lock = NULL; + bool has_one_lock = false; + for (uint i = 0; i < this->outcnt(); i++) { + Node* n = this->raw_out(i); + if (n->is_Phi()) + return false; // Merged regions + if (n->is_AbstractLock()) { + AbstractLockNode* alock = n->as_AbstractLock(); + // Check lock's box since box could be referenced by Lock's debug info. + if (alock->box_node() == this) { + if (alock->obj_node() == obj) { + if ((unique_lock != NULL) && alock->is_Lock()) { + if (lock == NULL) { + lock = alock->as_Lock(); + has_one_lock = true; + } else if (lock != alock->as_Lock()) { + has_one_lock = false; + } + } + } else { + return false; // Different objects + } + } + } + } +#ifdef ASSERT + // Verify that FastLock and Safepoint reference only this lock region. + for (uint i = 0; i < this->outcnt(); i++) { + Node* n = this->raw_out(i); + if (n->is_FastLock()) { + FastLockNode* flock = n->as_FastLock(); + assert((flock->box_node() == this) && (flock->obj_node() == obj),""); + } + if (n->is_SafePoint() && n->as_SafePoint()->jvms()) { + SafePointNode* sfn = n->as_SafePoint(); + JVMState* youngest_jvms = sfn->jvms(); + int max_depth = youngest_jvms->depth(); + for (int depth = 1; depth <= max_depth; depth++) { + JVMState* jvms = youngest_jvms->of_depth(depth); + int num_mon = jvms->nof_monitors(); + // Loop over monitors + for (int idx = 0; idx < num_mon; idx++) { + Node* obj_node = sfn->monitor_obj(jvms, idx); + Node* box_node = sfn->monitor_box(jvms, idx); + if (box_node == this) { + assert(obj_node == obj,""); + } + } + } + } + } +#endif + if (unique_lock != NULL && has_one_lock) { + *unique_lock = lock; + } + return true; } //=============================================================================