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6696264: assert("narrow oop can never be zero") for GCBasher & ParNewGC

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Decouple set_klass() with zeroing the gap when compressed.

Reviewed-by: kvn, ysr, jrose
This commit is contained in:
Coleen Phillimore 2008-05-28 21:06:24 -07:00
parent 1f9e095ee3
commit 646ceb4a45
12 changed files with 67 additions and 20 deletions
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25
hotspot/src/share/vm/oops/oop.inline.hpp
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@ -36,7 +36,15 @@ inline markOop oopDesc::cas_set_mark(markOop new_mark, markOop old_mark) {
inline klassOop oopDesc::klass() const {
if (UseCompressedOops) {
return (klassOop)decode_heap_oop_not_null(_metadata._compressed_klass);
// can be NULL in CMS, but isn't supported on CMS yet.
} else {
return _metadata._klass;
}
}
inline klassOop oopDesc::klass_or_null() const volatile {
// can be NULL in CMS
if (UseCompressedOops) {
return (klassOop)decode_heap_oop(_metadata._compressed_klass);
} else {
return _metadata._klass;
}
@ -64,15 +72,22 @@ inline void oopDesc::set_klass(klassOop k) {
assert(Universe::is_bootstrapping() || k != NULL, "must be a real klassOop");
assert(Universe::is_bootstrapping() || k->is_klass(), "not a klassOop");
if (UseCompressedOops) {
// zero the gap when the klass is set, by zeroing the pointer sized
// part of the union.
_metadata._klass = NULL;
oop_store_without_check(compressed_klass_addr(), (oop)k);
} else {
oop_store_without_check(klass_addr(), (oop) k);
}
}
inline int oopDesc::klass_gap() const {
return *(int*)(((intptr_t)this) + klass_gap_offset_in_bytes());
}
inline void oopDesc::set_klass_gap(int v) {
if (UseCompressedOops) {
*(int*)(((intptr_t)this) + klass_gap_offset_in_bytes()) = v;
}
}
inline void oopDesc::set_klass_to_list_ptr(oop k) {
// This is only to be used during GC, for from-space objects, so no
// barrier is needed.
@ -505,7 +520,7 @@ inline bool oopDesc::is_oop(bool ignore_mark_word) const {
// try to find metaclass cycle safely without seg faulting on bad input
// we should reach klassKlassObj by following klass link at most 3 times
for (int i = 0; i < 3; i++) {
obj = obj->klass();
obj = obj->klass_or_null();
// klass should be aligned and in permspace
if (!check_obj_alignment(obj)) return false;
if (!Universe::heap()->is_in_permanent(obj)) return false;