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7121140: Allocation paths require explicit memory synchronization operations for RMO systems

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Adds store store barrier after initialization of header and body of objects.

Reviewed-by: never, kvn
This commit is contained in:
Roland Westrelin 2011-12-20 16:56:50 +01:00
parent e057d60ca1
commit 97439fb4ff
13 changed files with 196 additions and 7 deletions
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62
hotspot/src/share/vm/opto/macro.cpp
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@ -1088,6 +1088,12 @@ void PhaseMacroExpand::expand_allocate_common(
Node* klass_node = alloc->in(AllocateNode::KlassNode);
Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
Node* storestore = alloc->storestore();
if (storestore != NULL) {
// Break this link that is no longer useful and confuses register allocation
storestore->set_req(MemBarNode::Precedent, top());
}
assert(ctrl != NULL, "must have control");
// We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
// they will not be used if "always_slow" is set
@ -1289,10 +1295,66 @@ void PhaseMacroExpand::expand_allocate_common(
0, new_alloc_bytes, T_LONG);
}
InitializeNode* init = alloc->initialization();
fast_oop_rawmem = initialize_object(alloc,
fast_oop_ctrl, fast_oop_rawmem, fast_oop,
klass_node, length, size_in_bytes);
// If initialization is performed by an array copy, any required
// MemBarStoreStore was already added. If the object does not
// escape no need for a MemBarStoreStore. Otherwise we need a
// MemBarStoreStore so that stores that initialize this object
// can't be reordered with a subsequent store that makes this
// object accessible by other threads.
if (init == NULL || (!init->is_complete_with_arraycopy() && !init->does_not_escape())) {
if (init == NULL || init->req() < InitializeNode::RawStores) {
// No InitializeNode or no stores captured by zeroing
// elimination. Simply add the MemBarStoreStore after object
// initialization.
MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot, fast_oop_rawmem);
transform_later(mb);
mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
mb->init_req(TypeFunc::Control, fast_oop_ctrl);
fast_oop_ctrl = new (C, 1) ProjNode(mb,TypeFunc::Control);
transform_later(fast_oop_ctrl);
fast_oop_rawmem = new (C, 1) ProjNode(mb,TypeFunc::Memory);
transform_later(fast_oop_rawmem);
} else {
// Add the MemBarStoreStore after the InitializeNode so that
// all stores performing the initialization that were moved
// before the InitializeNode happen before the storestore
// barrier.
Node* init_ctrl = init->proj_out(TypeFunc::Control);
Node* init_mem = init->proj_out(TypeFunc::Memory);
MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
transform_later(mb);
Node* ctrl = new (C, 1) ProjNode(init,TypeFunc::Control);
transform_later(ctrl);
Node* mem = new (C, 1) ProjNode(init,TypeFunc::Memory);
transform_later(mem);
// The MemBarStoreStore depends on control and memory coming
// from the InitializeNode
mb->init_req(TypeFunc::Memory, mem);
mb->init_req(TypeFunc::Control, ctrl);
ctrl = new (C, 1) ProjNode(mb,TypeFunc::Control);
transform_later(ctrl);
mem = new (C, 1) ProjNode(mb,TypeFunc::Memory);
transform_later(mem);
// All nodes that depended on the InitializeNode for control
// and memory must now depend on the MemBarNode that itself
// depends on the InitializeNode
_igvn.replace_node(init_ctrl, ctrl);
_igvn.replace_node(init_mem, mem);
}
}
if (C->env()->dtrace_extended_probes()) {
// Slow-path call
int size = TypeFunc::Parms + 2;