1.1 --- a/src/share/vm/opto/memnode.cpp Tue Dec 08 16:27:21 2009 -0800
1.2 +++ b/src/share/vm/opto/memnode.cpp Wed Dec 09 16:40:45 2009 -0800
1.3 @@ -123,6 +123,13 @@
1.4 } else {
1.5 assert(false, "unexpected projection");
1.6 }
1.7 + } else if (result->is_ClearArray()) {
1.8 + if (!ClearArrayNode::step_through(&result, instance_id, phase)) {
1.9 + // Can not bypass initialization of the instance
1.10 + // we are looking for.
1.11 + break;
1.12 + }
1.13 + // Otherwise skip it (the call updated 'result' value).
1.14 } else if (result->is_MergeMem()) {
1.15 result = step_through_mergemem(phase, result->as_MergeMem(), t_adr, NULL, tty);
1.16 }
1.17 @@ -537,6 +544,15 @@
1.18 } else if (mem->is_Proj() && mem->in(0)->is_MemBar()) {
1.19 mem = mem->in(0)->in(TypeFunc::Memory);
1.20 continue; // (a) advance through independent MemBar memory
1.21 + } else if (mem->is_ClearArray()) {
1.22 + if (ClearArrayNode::step_through(&mem, (uint)addr_t->instance_id(), phase)) {
1.23 + // (the call updated 'mem' value)
1.24 + continue; // (a) advance through independent allocation memory
1.25 + } else {
1.26 + // Can not bypass initialization of the instance
1.27 + // we are looking for.
1.28 + return mem;
1.29 + }
1.30 } else if (mem->is_MergeMem()) {
1.31 int alias_idx = phase->C->get_alias_index(adr_type());
1.32 mem = mem->as_MergeMem()->memory_at(alias_idx);
1.33 @@ -2454,6 +2470,31 @@
1.34 return mem;
1.35 }
1.36
1.37 +//----------------------------step_through----------------------------------
1.38 +// Return allocation input memory edge if it is different instance
1.39 +// or itself if it is the one we are looking for.
1.40 +bool ClearArrayNode::step_through(Node** np, uint instance_id, PhaseTransform* phase) {
1.41 + Node* n = *np;
1.42 + assert(n->is_ClearArray(), "sanity");
1.43 + intptr_t offset;
1.44 + AllocateNode* alloc = AllocateNode::Ideal_allocation(n->in(3), phase, offset);
1.45 + // This method is called only before Allocate nodes are expanded during
1.46 + // macro nodes expansion. Before that ClearArray nodes are only generated
1.47 + // in LibraryCallKit::generate_arraycopy() which follows allocations.
1.48 + assert(alloc != NULL, "should have allocation");
1.49 + if (alloc->_idx == instance_id) {
1.50 + // Can not bypass initialization of the instance we are looking for.
1.51 + return false;
1.52 + }
1.53 + // Otherwise skip it.
1.54 + InitializeNode* init = alloc->initialization();
1.55 + if (init != NULL)
1.56 + *np = init->in(TypeFunc::Memory);
1.57 + else
1.58 + *np = alloc->in(TypeFunc::Memory);
1.59 + return true;
1.60 +}
1.61 +
1.62 //----------------------------clear_memory-------------------------------------
1.63 // Generate code to initialize object storage to zero.
1.64 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
1.65 @@ -2627,7 +2668,30 @@
1.66 // Return a node which is more "ideal" than the current node. Strip out
1.67 // control copies
1.68 Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1.69 - return remove_dead_region(phase, can_reshape) ? this : NULL;
1.70 + if (remove_dead_region(phase, can_reshape)) return this;
1.71 +
1.72 + // Eliminate volatile MemBars for scalar replaced objects.
1.73 + if (can_reshape && req() == (Precedent+1) &&
1.74 + (Opcode() == Op_MemBarAcquire || Opcode() == Op_MemBarVolatile)) {
1.75 + // Volatile field loads and stores.
1.76 + Node* my_mem = in(MemBarNode::Precedent);
1.77 + if (my_mem != NULL && my_mem->is_Mem()) {
1.78 + const TypeOopPtr* t_oop = my_mem->in(MemNode::Address)->bottom_type()->isa_oopptr();
1.79 + // Check for scalar replaced object reference.
1.80 + if( t_oop != NULL && t_oop->is_known_instance_field() &&
1.81 + t_oop->offset() != Type::OffsetBot &&
1.82 + t_oop->offset() != Type::OffsetTop) {
1.83 + // Replace MemBar projections by its inputs.
1.84 + PhaseIterGVN* igvn = phase->is_IterGVN();
1.85 + igvn->replace_node(proj_out(TypeFunc::Memory), in(TypeFunc::Memory));
1.86 + igvn->replace_node(proj_out(TypeFunc::Control), in(TypeFunc::Control));
1.87 + // Must return either the original node (now dead) or a new node
1.88 + // (Do not return a top here, since that would break the uniqueness of top.)
1.89 + return new (phase->C, 1) ConINode(TypeInt::ZERO);
1.90 + }
1.91 + }
1.92 + }
1.93 + return NULL;
1.94 }
1.95
1.96 //------------------------------Value------------------------------------------
