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7059039: EA: don't change non-escaping state of NULL pointer

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NULL pointers do not escape but escape state propagation may change it leading to worser results.

Reviewed-by: never
This commit is contained in:
Vladimir Kozlov 2011-10-25 12:51:13 -07:00
parent 160ad3376d
commit 952f0b9b81
1 changed files with 23 additions and 11 deletions
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34
hotspot/src/share/vm/opto/escape.cpp
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@ -108,14 +108,16 @@ ConnectionGraph::ConnectionGraph(Compile * C, PhaseIterGVN *igvn) :
// Add ConP(#NULL) and ConN(#NULL) nodes.
Node* oop_null = igvn->zerocon(T_OBJECT);
_oop_null = oop_null->_idx;
assert(_oop_null < C->unique(), "should be created already");
assert(_oop_null < nodes_size(), "should be created already");
add_node(oop_null, PointsToNode::JavaObject, PointsToNode::NoEscape, true);
if (UseCompressedOops) {
Node* noop_null = igvn->zerocon(T_NARROWOOP);
_noop_null = noop_null->_idx;
assert(_noop_null < C->unique(), "should be created already");
assert(_noop_null < nodes_size(), "should be created already");
add_node(noop_null, PointsToNode::JavaObject, PointsToNode::NoEscape, true);
} else {
_noop_null = _oop_null; // Should be initialized
}
}
@ -174,6 +176,9 @@ void ConnectionGraph::add_field_edge(uint from_i, uint to_i, int offset) {
}
void ConnectionGraph::set_escape_state(uint ni, PointsToNode::EscapeState es) {
// Don't change non-escaping state of NULL pointer.
if (ni == _noop_null || ni == _oop_null)
return;
PointsToNode *npt = ptnode_adr(ni);
PointsToNode::EscapeState old_es = npt->escape_state();
if (es > old_es)
@ -231,8 +236,8 @@ PointsToNode::EscapeState ConnectionGraph::escape_state(Node *n) {
}
if (orig_es != es) {
// cache the computed escape state
assert(es != PointsToNode::UnknownEscape, "should have computed an escape state");
ptnode_adr(idx)->set_escape_state(es);
assert(es > orig_es, "should have computed an escape state");
set_escape_state(idx, es);
} // orig_es could be PointsToNode::UnknownEscape
return es;
}
@ -334,7 +339,7 @@ void ConnectionGraph::remove_deferred(uint ni, GrowableArray<uint>* deferred_edg
add_pointsto_edge(ni, etgt);
if(etgt == _phantom_object) {
// Special case - field set outside (globally escaping).
ptn->set_escape_state(PointsToNode::GlobalEscape);
set_escape_state(ni, PointsToNode::GlobalEscape);
}
} else if (et == PointsToNode::DeferredEdge) {
deferred_edges->append(etgt);
@ -1686,7 +1691,7 @@ bool ConnectionGraph::compute_escape() {
uint npi = ptn->edge_target(ei);
PointsToNode *np = ptnode_adr(npi);
if (np->escape_state() < PointsToNode::GlobalEscape) {
np->set_escape_state(PointsToNode::GlobalEscape);
set_escape_state(npi, PointsToNode::GlobalEscape);
worklist.push(npi);
}
}
@ -1708,7 +1713,7 @@ bool ConnectionGraph::compute_escape() {
uint npi = ptn->edge_target(ei);
PointsToNode *np = ptnode_adr(npi);
if (np->escape_state() < PointsToNode::ArgEscape) {
np->set_escape_state(PointsToNode::ArgEscape);
set_escape_state(npi, PointsToNode::ArgEscape);
worklist.push(npi);
}
}
@ -1724,9 +1729,11 @@ bool ConnectionGraph::compute_escape() {
}
// mark all nodes reachable from NoEscape nodes
while(worklist.length() > 0) {
PointsToNode* ptn = ptnode_adr(worklist.pop());
if (ptn->node_type() == PointsToNode::JavaObject)
has_non_escaping_obj = true; // Non GlobalEscape
uint nk = worklist.pop();
PointsToNode* ptn = ptnode_adr(nk);
if (ptn->node_type() == PointsToNode::JavaObject &&
!(nk == _noop_null || nk == _oop_null))
has_non_escaping_obj = true; // Non Escape
Node* n = ptn->_node;
if (n->is_Allocate() && ptn->_scalar_replaceable ) {
// Push scalar replaceable allocations on alloc_worklist
@ -1738,7 +1745,7 @@ bool ConnectionGraph::compute_escape() {
uint npi = ptn->edge_target(ei);
PointsToNode *np = ptnode_adr(npi);
if (np->escape_state() < PointsToNode::NoEscape) {
np->set_escape_state(PointsToNode::NoEscape);
set_escape_state(npi, PointsToNode::NoEscape);
worklist.push(npi);
}
}
@ -1747,6 +1754,11 @@ bool ConnectionGraph::compute_escape() {
_collecting = false;
assert(C->unique() == nodes_size(), "there should be no new ideal nodes during ConnectionGraph build");
assert(ptnode_adr(_oop_null)->escape_state() == PointsToNode::NoEscape, "sanity");
if (UseCompressedOops) {
assert(ptnode_adr(_noop_null)->escape_state() == PointsToNode::NoEscape, "sanity");
}
if (EliminateLocks) {
// Mark locks before changing ideal graph.
int cnt = C->macro_count();