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8027388: JVM crashes with SIGSEGV (0xb) at pc=0x00000001077cbbf6

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Make object non-scalarizable if it has field with multiple bases one of which is null

Reviewed-by: kvn, twisti
This commit is contained in:
Igor Veresov 2013-12-26 21:00:23 -08:00
parent 2eb5e0e89d
commit cfefd04320
1 changed files with 15 additions and 4 deletions
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19
hotspot/src/share/vm/opto/escape.cpp
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@ -1579,9 +1579,20 @@ void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
jobj->set_scalar_replaceable(false);
return;
}
// 2. An object is not scalar replaceable if the field into which it is
// stored has multiple bases one of which is null.
if (field->base_count() > 1) {
for (BaseIterator i(field); i.has_next(); i.next()) {
PointsToNode* base = i.get();
if (base == null_obj) {
jobj->set_scalar_replaceable(false);
return;
}
}
}
}
assert(use->is_Field() || use->is_LocalVar(), "sanity");
// 2. An object is not scalar replaceable if it is merged with other objects.
// 3. An object is not scalar replaceable if it is merged with other objects.
for (EdgeIterator j(use); j.has_next(); j.next()) {
PointsToNode* ptn = j.get();
if (ptn->is_JavaObject() && ptn != jobj) {
@ -1600,13 +1611,13 @@ void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
FieldNode* field = j.get()->as_Field();
int offset = field->as_Field()->offset();
// 3. An object is not scalar replaceable if it has a field with unknown
// 4. An object is not scalar replaceable if it has a field with unknown
// offset (array's element is accessed in loop).
if (offset == Type::OffsetBot) {
jobj->set_scalar_replaceable(false);
return;
}
// 4. Currently an object is not scalar replaceable if a LoadStore node
// 5. Currently an object is not scalar replaceable if a LoadStore node
// access its field since the field value is unknown after it.
//
Node* n = field->ideal_node();
@ -1617,7 +1628,7 @@ void ConnectionGraph::adjust_scalar_replaceable_state(JavaObjectNode* jobj) {
}
}
// 5. Or the address may point to more then one object. This may produce
// 6. Or the address may point to more then one object. This may produce
// the false positive result (set not scalar replaceable)
// since the flow-insensitive escape analysis can't separate
// the case when stores overwrite the field's value from the case