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6918185: Remove unused code for lost card-marking optimization in BacktraceBuilder

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Removed dead code

Reviewed-by: ysr, coleenp, dholmes
This commit is contained in:
Bengt Rutisson 2011-06-13 13:48:18 +02:00
parent 9ca97e4c78
commit c0d64ac595
1 changed files with 1 additions and 28 deletions
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29
hotspot/src/share/vm/classfile/javaClasses.cpp
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@ -1258,7 +1258,6 @@ class BacktraceBuilder: public StackObj {
objArrayOop _methods;
typeArrayOop _bcis;
int _index;
bool _dirty;
No_Safepoint_Verifier _nsv;
public:
@ -1272,37 +1271,13 @@ class BacktraceBuilder: public StackObj {
};
// constructor for new backtrace
BacktraceBuilder(TRAPS): _methods(NULL), _bcis(NULL), _head(NULL), _dirty(false) {
BacktraceBuilder(TRAPS): _methods(NULL), _bcis(NULL), _head(NULL) {
expand(CHECK);
_backtrace = _head;
_index = 0;
}
void flush() {
// The following appears to have been an optimization to save from
// doing a barrier for each individual store into the _methods array,
// but rather to do it for the entire array after the series of writes.
// That optimization seems to have been lost when compressed oops was
// implemented. However, the extra card-marks below was left in place,
// but is now redundant because the individual stores into the
// _methods array already execute the barrier code. CR 6918185 has
// been filed so the original code may be restored by deferring the
// barriers until after the entire sequence of stores, thus re-enabling
// the intent of the original optimization. In the meantime the redundant
// card mark below is now disabled.
if (_dirty && _methods != NULL) {
#if 0
BarrierSet* bs = Universe::heap()->barrier_set();
assert(bs->has_write_ref_array_opt(), "Barrier set must have ref array opt");
bs->write_ref_array((HeapWord*)_methods->base(), _methods->length());
#endif
_dirty = false;
}
}
void expand(TRAPS) {
flush();
objArrayHandle old_head(THREAD, _head);
Pause_No_Safepoint_Verifier pnsv(&_nsv);
@ -1328,7 +1303,6 @@ class BacktraceBuilder: public StackObj {
}
oop backtrace() {
flush();
return _backtrace();
}
@ -1342,7 +1316,6 @@ class BacktraceBuilder: public StackObj {
_methods->obj_at_put(_index, method);
_bcis->ushort_at_put(_index, bci);
_index++;
_dirty = true;
}
methodOop current_method() {