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7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error

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A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.

Reviewed-by: kvn, iveresov, never, tonyp, dholmes
This commit is contained in:
John Cuthbertson 2011-04-07 09:53:20 -07:00
parent aac4647e6e
commit a08e1ce906
41 changed files with 1423 additions and 268 deletions
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65
hotspot/src/share/vm/opto/graphKit.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -1457,19 +1457,22 @@ Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,
}
void GraphKit::pre_barrier(Node* ctl,
void GraphKit::pre_barrier(bool do_load,
Node* ctl,
Node* obj,
Node* adr,
uint adr_idx,
Node* val,
const TypeOopPtr* val_type,
Node* pre_val,
BasicType bt) {
BarrierSet* bs = Universe::heap()->barrier_set();
set_control(ctl);
switch (bs->kind()) {
case BarrierSet::G1SATBCT:
case BarrierSet::G1SATBCTLogging:
g1_write_barrier_pre(obj, adr, adr_idx, val, val_type, bt);
g1_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
break;
case BarrierSet::CardTableModRef:
@ -1532,7 +1535,11 @@ Node* GraphKit::store_oop(Node* ctl,
uint adr_idx = C->get_alias_index(adr_type);
assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
pre_barrier(control(), obj, adr, adr_idx, val, val_type, bt);
pre_barrier(true /* do_load */,
control(), obj, adr, adr_idx, val, val_type,
NULL /* pre_val */,
bt);
Node* store = store_to_memory(control(), adr, val, bt, adr_idx);
post_barrier(control(), store, obj, adr, adr_idx, val, bt, use_precise);
return store;
@ -3465,12 +3472,31 @@ void GraphKit::write_barrier_post(Node* oop_store,
}
// G1 pre/post barriers
void GraphKit::g1_write_barrier_pre(Node* obj,
void GraphKit::g1_write_barrier_pre(bool do_load,
Node* obj,
Node* adr,
uint alias_idx,
Node* val,
const TypeOopPtr* val_type,
Node* pre_val,
BasicType bt) {
// Some sanity checks
// Note: val is unused in this routine.
if (do_load) {
// We need to generate the load of the previous value
assert(obj != NULL, "must have a base");
assert(adr != NULL, "where are loading from?");
assert(pre_val == NULL, "loaded already?");
assert(val_type != NULL, "need a type");
} else {
// In this case both val_type and alias_idx are unused.
assert(pre_val != NULL, "must be loaded already");
assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
}
assert(bt == T_OBJECT, "or we shouldn't be here");
IdealKit ideal(gvn(), control(), merged_memory(), true);
Node* tls = __ thread(); // ThreadLocalStorage
@ -3492,32 +3518,28 @@ void GraphKit::g1_write_barrier_pre(Node* obj,
PtrQueue::byte_offset_of_index());
const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
PtrQueue::byte_offset_of_buf());
// Now the actual pointers into the thread
// set_control( ctl);
Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
// Now some of the values
Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
// if (!marking)
__ if_then(marking, BoolTest::ne, zero); {
Node* index = __ load(__ ctrl(), index_adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw);
const Type* t1 = adr->bottom_type();
const Type* t2 = val->bottom_type();
Node* orig = __ load(no_ctrl, adr, val_type, bt, alias_idx);
// if (orig != NULL)
__ if_then(orig, BoolTest::ne, null()); {
Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
if (do_load) {
// load original value
// alias_idx correct??
pre_val = __ load(no_ctrl, adr, val_type, bt, alias_idx);
}
// if (pre_val != NULL)
__ if_then(pre_val, BoolTest::ne, null()); {
Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
// is the queue for this thread full?
__ if_then(index, BoolTest::ne, zero, likely); {
@ -3531,10 +3553,9 @@ void GraphKit::g1_write_barrier_pre(Node* obj,
next_indexX = _gvn.transform( new (C, 2) ConvI2LNode(next_index, TypeLong::make(0, max_jlong, Type::WidenMax)) );
#endif
// Now get the buffer location we will log the original value into and store it
// Now get the buffer location we will log the previous value into and store it
Node *log_addr = __ AddP(no_base, buffer, next_indexX);
__ store(__ ctrl(), log_addr, orig, T_OBJECT, Compile::AliasIdxRaw);
__ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw);
// update the index
__ store(__ ctrl(), index_adr, next_index, T_INT, Compile::AliasIdxRaw);
@ -3542,9 +3563,9 @@ void GraphKit::g1_write_barrier_pre(Node* obj,
// logging buffer is full, call the runtime
const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
__ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", orig, tls);
__ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
} __ end_if(); // (!index)
} __ end_if(); // (orig != NULL)
} __ end_if(); // (pre_val != NULL)
} __ end_if(); // (!marking)
// Final sync IdealKit and GraphKit.