--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/opto/memnode.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,3222 @@
+/*
+ * Copyright 1997-2007 Sun Microsystems, Inc. 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+// Portions of code courtesy of Clifford Click
+
+// Optimization - Graph Style
+
+#include "incls/_precompiled.incl"
+#include "incls/_memnode.cpp.incl"
+
+//=============================================================================
+uint MemNode::size_of() const { return sizeof(*this); }
+
+const TypePtr *MemNode::adr_type() const {
+ Node* adr = in(Address);
+ const TypePtr* cross_check = NULL;
+ DEBUG_ONLY(cross_check = _adr_type);
+ return calculate_adr_type(adr->bottom_type(), cross_check);
+}
+
+#ifndef PRODUCT
+void MemNode::dump_spec(outputStream *st) const {
+ if (in(Address) == NULL) return; // node is dead
+#ifndef ASSERT
+ // fake the missing field
+ const TypePtr* _adr_type = NULL;
+ if (in(Address) != NULL)
+ _adr_type = in(Address)->bottom_type()->isa_ptr();
+#endif
+ dump_adr_type(this, _adr_type, st);
+
+ Compile* C = Compile::current();
+ if( C->alias_type(_adr_type)->is_volatile() )
+ st->print(" Volatile!");
+}
+
+void MemNode::dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st) {
+ st->print(" @");
+ if (adr_type == NULL) {
+ st->print("NULL");
+ } else {
+ adr_type->dump_on(st);
+ Compile* C = Compile::current();
+ Compile::AliasType* atp = NULL;
+ if (C->have_alias_type(adr_type)) atp = C->alias_type(adr_type);
+ if (atp == NULL)
+ st->print(", idx=?\?;");
+ else if (atp->index() == Compile::AliasIdxBot)
+ st->print(", idx=Bot;");
+ else if (atp->index() == Compile::AliasIdxTop)
+ st->print(", idx=Top;");
+ else if (atp->index() == Compile::AliasIdxRaw)
+ st->print(", idx=Raw;");
+ else {
+ ciField* field = atp->field();
+ if (field) {
+ st->print(", name=");
+ field->print_name_on(st);
+ }
+ st->print(", idx=%d;", atp->index());
+ }
+ }
+}
+
+extern void print_alias_types();
+
+#endif
+
+//--------------------------Ideal_common---------------------------------------
+// Look for degenerate control and memory inputs. Bypass MergeMem inputs.
+// Unhook non-raw memories from complete (macro-expanded) initializations.
+Node *MemNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
+ // If our control input is a dead region, kill all below the region
+ Node *ctl = in(MemNode::Control);
+ if (ctl && remove_dead_region(phase, can_reshape))
+ return this;
+
+ // Ignore if memory is dead, or self-loop
+ Node *mem = in(MemNode::Memory);
+ if( phase->type( mem ) == Type::TOP ) return NodeSentinel; // caller will return NULL
+ assert( mem != this, "dead loop in MemNode::Ideal" );
+
+ Node *address = in(MemNode::Address);
+ const Type *t_adr = phase->type( address );
+ if( t_adr == Type::TOP ) return NodeSentinel; // caller will return NULL
+
+ // Avoid independent memory operations
+ Node* old_mem = mem;
+
+ if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
+ InitializeNode* init = mem->in(0)->as_Initialize();
+ if (init->is_complete()) { // i.e., after macro expansion
+ const TypePtr* tp = t_adr->is_ptr();
+ uint alias_idx = phase->C->get_alias_index(tp);
+ // Free this slice from the init. It was hooked, temporarily,
+ // by GraphKit::set_output_for_allocation.
+ if (alias_idx > Compile::AliasIdxRaw) {
+ mem = init->memory(alias_idx);
+ // ...but not with the raw-pointer slice.
+ }
+ }
+ }
+
+ if (mem->is_MergeMem()) {
+ MergeMemNode* mmem = mem->as_MergeMem();
+ const TypePtr *tp = t_adr->is_ptr();
+ uint alias_idx = phase->C->get_alias_index(tp);
+#ifdef ASSERT
+ {
+ // Check that current type is consistent with the alias index used during graph construction
+ assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx");
+ const TypePtr *adr_t = adr_type();
+ bool consistent = adr_t == NULL || adr_t->empty() || phase->C->must_alias(adr_t, alias_idx );
+ // Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
+ if( !consistent && adr_t != NULL && !adr_t->empty() &&
+ tp->isa_aryptr() && tp->offset() == Type::OffsetBot &&
+ adr_t->isa_aryptr() && adr_t->offset() != Type::OffsetBot &&
+ ( adr_t->offset() == arrayOopDesc::length_offset_in_bytes() ||
+ adr_t->offset() == oopDesc::klass_offset_in_bytes() ||
+ adr_t->offset() == oopDesc::mark_offset_in_bytes() ) ) {
+ // don't assert if it is dead code.
+ consistent = true;
+ }
+ if( !consistent ) {
+ tty->print("alias_idx==%d, adr_type()==", alias_idx); if( adr_t == NULL ) { tty->print("NULL"); } else { adr_t->dump(); }
+ tty->cr();
+ print_alias_types();
+ assert(consistent, "adr_type must match alias idx");
+ }
+ }
+#endif
+ // TypeInstPtr::NOTNULL+any is an OOP with unknown offset - generally
+ // means an array I have not precisely typed yet. Do not do any
+ // alias stuff with it any time soon.
+ const TypeInstPtr *tinst = tp->isa_instptr();
+ if( tp->base() != Type::AnyPtr &&
+ !(tinst &&
+ tinst->klass()->is_java_lang_Object() &&
+ tinst->offset() == Type::OffsetBot) ) {
+ // compress paths and change unreachable cycles to TOP
+ // If not, we can update the input infinitely along a MergeMem cycle
+ // Equivalent code in PhiNode::Ideal
+ Node* m = phase->transform(mmem);
+ // If tranformed to a MergeMem, get the desired slice
+ // Otherwise the returned node represents memory for every slice
+ mem = (m->is_MergeMem())? m->as_MergeMem()->memory_at(alias_idx) : m;
+ // Update input if it is progress over what we have now
+ }
+ }
+
+ if (mem != old_mem) {
+ set_req(MemNode::Memory, mem);
+ return this;
+ }
+
+ // let the subclass continue analyzing...
+ return NULL;
+}
+
+// Helper function for proving some simple control dominations.
+// Attempt to prove that control input 'dom' dominates (or equals) 'sub'.
+// Already assumes that 'dom' is available at 'sub', and that 'sub'
+// is not a constant (dominated by the method's StartNode).
+// Used by MemNode::find_previous_store to prove that the
+// control input of a memory operation predates (dominates)
+// an allocation it wants to look past.
+bool MemNode::detect_dominating_control(Node* dom, Node* sub) {
+ if (dom == NULL) return false;
+ if (dom->is_Proj()) dom = dom->in(0);
+ if (dom->is_Start()) return true; // anything inside the method
+ if (dom->is_Root()) return true; // dom 'controls' a constant
+ int cnt = 20; // detect cycle or too much effort
+ while (sub != NULL) { // walk 'sub' up the chain to 'dom'
+ if (--cnt < 0) return false; // in a cycle or too complex
+ if (sub == dom) return true;
+ if (sub->is_Start()) return false;
+ if (sub->is_Root()) return false;
+ Node* up = sub->in(0);
+ if (sub == up && sub->is_Region()) {
+ for (uint i = 1; i < sub->req(); i++) {
+ Node* in = sub->in(i);
+ if (in != NULL && !in->is_top() && in != sub) {
+ up = in; break; // take any path on the way up to 'dom'
+ }
+ }
+ }
+ if (sub == up) return false; // some kind of tight cycle
+ sub = up;
+ }
+ return false;
+}
+
+//---------------------detect_ptr_independence---------------------------------
+// Used by MemNode::find_previous_store to prove that two base
+// pointers are never equal.
+// The pointers are accompanied by their associated allocations,
+// if any, which have been previously discovered by the caller.
+bool MemNode::detect_ptr_independence(Node* p1, AllocateNode* a1,
+ Node* p2, AllocateNode* a2,
+ PhaseTransform* phase) {
+ // Attempt to prove that these two pointers cannot be aliased.
+ // They may both manifestly be allocations, and they should differ.
+ // Or, if they are not both allocations, they can be distinct constants.
+ // Otherwise, one is an allocation and the other a pre-existing value.
+ if (a1 == NULL && a2 == NULL) { // neither an allocation
+ return (p1 != p2) && p1->is_Con() && p2->is_Con();
+ } else if (a1 != NULL && a2 != NULL) { // both allocations
+ return (a1 != a2);
+ } else if (a1 != NULL) { // one allocation a1
+ // (Note: p2->is_Con implies p2->in(0)->is_Root, which dominates.)
+ return detect_dominating_control(p2->in(0), a1->in(0));
+ } else { //(a2 != NULL) // one allocation a2
+ return detect_dominating_control(p1->in(0), a2->in(0));
+ }
+ return false;
+}
+
+
+// The logic for reordering loads and stores uses four steps:
+// (a) Walk carefully past stores and initializations which we
+// can prove are independent of this load.
+// (b) Observe that the next memory state makes an exact match
+// with self (load or store), and locate the relevant store.
+// (c) Ensure that, if we were to wire self directly to the store,
+// the optimizer would fold it up somehow.
+// (d) Do the rewiring, and return, depending on some other part of
+// the optimizer to fold up the load.
+// This routine handles steps (a) and (b). Steps (c) and (d) are
+// specific to loads and stores, so they are handled by the callers.
+// (Currently, only LoadNode::Ideal has steps (c), (d). More later.)
+//
+Node* MemNode::find_previous_store(PhaseTransform* phase) {
+ Node* ctrl = in(MemNode::Control);
+ Node* adr = in(MemNode::Address);
+ intptr_t offset = 0;
+ Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+ AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
+
+ if (offset == Type::OffsetBot)
+ return NULL; // cannot unalias unless there are precise offsets
+
+ intptr_t size_in_bytes = memory_size();
+
+ Node* mem = in(MemNode::Memory); // start searching here...
+
+ int cnt = 50; // Cycle limiter
+ for (;;) { // While we can dance past unrelated stores...
+ if (--cnt < 0) break; // Caught in cycle or a complicated dance?
+
+ if (mem->is_Store()) {
+ Node* st_adr = mem->in(MemNode::Address);
+ intptr_t st_offset = 0;
+ Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
+ if (st_base == NULL)
+ break; // inscrutable pointer
+ if (st_offset != offset && st_offset != Type::OffsetBot) {
+ const int MAX_STORE = BytesPerLong;
+ if (st_offset >= offset + size_in_bytes ||
+ st_offset <= offset - MAX_STORE ||
+ st_offset <= offset - mem->as_Store()->memory_size()) {
+ // Success: The offsets are provably independent.
+ // (You may ask, why not just test st_offset != offset and be done?
+ // The answer is that stores of different sizes can co-exist
+ // in the same sequence of RawMem effects. We sometimes initialize
+ // a whole 'tile' of array elements with a single jint or jlong.)
+ mem = mem->in(MemNode::Memory);
+ continue; // (a) advance through independent store memory
+ }
+ }
+ if (st_base != base &&
+ detect_ptr_independence(base, alloc,
+ st_base,
+ AllocateNode::Ideal_allocation(st_base, phase),
+ phase)) {
+ // Success: The bases are provably independent.
+ mem = mem->in(MemNode::Memory);
+ continue; // (a) advance through independent store memory
+ }
+
+ // (b) At this point, if the bases or offsets do not agree, we lose,
+ // since we have not managed to prove 'this' and 'mem' independent.
+ if (st_base == base && st_offset == offset) {
+ return mem; // let caller handle steps (c), (d)
+ }
+
+ } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
+ InitializeNode* st_init = mem->in(0)->as_Initialize();
+ AllocateNode* st_alloc = st_init->allocation();
+ if (st_alloc == NULL)
+ break; // something degenerated
+ bool known_identical = false;
+ bool known_independent = false;
+ if (alloc == st_alloc)
+ known_identical = true;
+ else if (alloc != NULL)
+ known_independent = true;
+ else if (ctrl != NULL &&
+ detect_dominating_control(ctrl, st_alloc->in(0)))
+ known_independent = true;
+
+ if (known_independent) {
+ // The bases are provably independent: Either they are
+ // manifestly distinct allocations, or else the control
+ // of this load dominates the store's allocation.
+ int alias_idx = phase->C->get_alias_index(adr_type());
+ if (alias_idx == Compile::AliasIdxRaw) {
+ mem = st_alloc->in(TypeFunc::Memory);
+ } else {
+ mem = st_init->memory(alias_idx);
+ }
+ continue; // (a) advance through independent store memory
+ }
+
+ // (b) at this point, if we are not looking at a store initializing
+ // the same allocation we are loading from, we lose.
+ if (known_identical) {
+ // From caller, can_see_stored_value will consult find_captured_store.
+ return mem; // let caller handle steps (c), (d)
+ }
+
+ }
+
+ // Unless there is an explicit 'continue', we must bail out here,
+ // because 'mem' is an inscrutable memory state (e.g., a call).
+ break;
+ }
+
+ return NULL; // bail out
+}
+
+//----------------------calculate_adr_type-------------------------------------
+// Helper function. Notices when the given type of address hits top or bottom.
+// Also, asserts a cross-check of the type against the expected address type.
+const TypePtr* MemNode::calculate_adr_type(const Type* t, const TypePtr* cross_check) {
+ if (t == Type::TOP) return NULL; // does not touch memory any more?
+ #ifdef PRODUCT
+ cross_check = NULL;
+ #else
+ if (!VerifyAliases || is_error_reported() || Node::in_dump()) cross_check = NULL;
+ #endif
+ const TypePtr* tp = t->isa_ptr();
+ if (tp == NULL) {
+ assert(cross_check == NULL || cross_check == TypePtr::BOTTOM, "expected memory type must be wide");
+ return TypePtr::BOTTOM; // touches lots of memory
+ } else {
+ #ifdef ASSERT
+ // %%%% [phh] We don't check the alias index if cross_check is
+ // TypeRawPtr::BOTTOM. Needs to be investigated.
+ if (cross_check != NULL &&
+ cross_check != TypePtr::BOTTOM &&
+ cross_check != TypeRawPtr::BOTTOM) {
+ // Recheck the alias index, to see if it has changed (due to a bug).
+ Compile* C = Compile::current();
+ assert(C->get_alias_index(cross_check) == C->get_alias_index(tp),
+ "must stay in the original alias category");
+ // The type of the address must be contained in the adr_type,
+ // disregarding "null"-ness.
+ // (We make an exception for TypeRawPtr::BOTTOM, which is a bit bucket.)
+ const TypePtr* tp_notnull = tp->join(TypePtr::NOTNULL)->is_ptr();
+ assert(cross_check->meet(tp_notnull) == cross_check,
+ "real address must not escape from expected memory type");
+ }
+ #endif
+ return tp;
+ }
+}
+
+//------------------------adr_phi_is_loop_invariant----------------------------
+// A helper function for Ideal_DU_postCCP to check if a Phi in a counted
+// loop is loop invariant. Make a quick traversal of Phi and associated
+// CastPP nodes, looking to see if they are a closed group within the loop.
+bool MemNode::adr_phi_is_loop_invariant(Node* adr_phi, Node* cast) {
+ // The idea is that the phi-nest must boil down to only CastPP nodes
+ // with the same data. This implies that any path into the loop already
+ // includes such a CastPP, and so the original cast, whatever its input,
+ // must be covered by an equivalent cast, with an earlier control input.
+ ResourceMark rm;
+
+ // The loop entry input of the phi should be the unique dominating
+ // node for every Phi/CastPP in the loop.
+ Unique_Node_List closure;
+ closure.push(adr_phi->in(LoopNode::EntryControl));
+
+ // Add the phi node and the cast to the worklist.
+ Unique_Node_List worklist;
+ worklist.push(adr_phi);
+ if( cast != NULL ){
+ if( !cast->is_ConstraintCast() ) return false;
+ worklist.push(cast);
+ }
+
+ // Begin recursive walk of phi nodes.
+ while( worklist.size() ){
+ // Take a node off the worklist
+ Node *n = worklist.pop();
+ if( !closure.member(n) ){
+ // Add it to the closure.
+ closure.push(n);
+ // Make a sanity check to ensure we don't waste too much time here.
+ if( closure.size() > 20) return false;
+ // This node is OK if:
+ // - it is a cast of an identical value
+ // - or it is a phi node (then we add its inputs to the worklist)
+ // Otherwise, the node is not OK, and we presume the cast is not invariant
+ if( n->is_ConstraintCast() ){
+ worklist.push(n->in(1));
+ } else if( n->is_Phi() ) {
+ for( uint i = 1; i < n->req(); i++ ) {
+ worklist.push(n->in(i));
+ }
+ } else {
+ return false;
+ }
+ }
+ }
+
+ // Quit when the worklist is empty, and we've found no offending nodes.
+ return true;
+}
+
+//------------------------------Ideal_DU_postCCP-------------------------------
+// Find any cast-away of null-ness and keep its control. Null cast-aways are
+// going away in this pass and we need to make this memory op depend on the
+// gating null check.
+
+// I tried to leave the CastPP's in. This makes the graph more accurate in
+// some sense; we get to keep around the knowledge that an oop is not-null
+// after some test. Alas, the CastPP's interfere with GVN (some values are
+// the regular oop, some are the CastPP of the oop, all merge at Phi's which
+// cannot collapse, etc). This cost us 10% on SpecJVM, even when I removed
+// some of the more trivial cases in the optimizer. Removing more useless
+// Phi's started allowing Loads to illegally float above null checks. I gave
+// up on this approach. CNC 10/20/2000
+Node *MemNode::Ideal_DU_postCCP( PhaseCCP *ccp ) {
+ Node *ctr = in(MemNode::Control);
+ Node *mem = in(MemNode::Memory);
+ Node *adr = in(MemNode::Address);
+ Node *skipped_cast = NULL;
+ // Need a null check? Regular static accesses do not because they are
+ // from constant addresses. Array ops are gated by the range check (which
+ // always includes a NULL check). Just check field ops.
+ if( !ctr ) {
+ // Scan upwards for the highest location we can place this memory op.
+ while( true ) {
+ switch( adr->Opcode() ) {
+
+ case Op_AddP: // No change to NULL-ness, so peek thru AddP's
+ adr = adr->in(AddPNode::Base);
+ continue;
+
+ case Op_CastPP:
+ // If the CastPP is useless, just peek on through it.
+ if( ccp->type(adr) == ccp->type(adr->in(1)) ) {
+ // Remember the cast that we've peeked though. If we peek
+ // through more than one, then we end up remembering the highest
+ // one, that is, if in a loop, the one closest to the top.
+ skipped_cast = adr;
+ adr = adr->in(1);
+ continue;
+ }
+ // CastPP is going away in this pass! We need this memory op to be
+ // control-dependent on the test that is guarding the CastPP.
+ ccp->hash_delete(this);
+ set_req(MemNode::Control, adr->in(0));
+ ccp->hash_insert(this);
+ return this;
+
+ case Op_Phi:
+ // Attempt to float above a Phi to some dominating point.
+ if (adr->in(0) != NULL && adr->in(0)->is_CountedLoop()) {
+ // If we've already peeked through a Cast (which could have set the
+ // control), we can't float above a Phi, because the skipped Cast
+ // may not be loop invariant.
+ if (adr_phi_is_loop_invariant(adr, skipped_cast)) {
+ adr = adr->in(1);
+ continue;
+ }
+ }
+
+ // Intentional fallthrough!
+
+ // No obvious dominating point. The mem op is pinned below the Phi
+ // by the Phi itself. If the Phi goes away (no true value is merged)
+ // then the mem op can float, but not indefinitely. It must be pinned
+ // behind the controls leading to the Phi.
+ case Op_CheckCastPP:
+ // These usually stick around to change address type, however a
+ // useless one can be elided and we still need to pick up a control edge
+ if (adr->in(0) == NULL) {
+ // This CheckCastPP node has NO control and is likely useless. But we
+ // need check further up the ancestor chain for a control input to keep
+ // the node in place. 4959717.
+ skipped_cast = adr;
+ adr = adr->in(1);
+ continue;
+ }
+ ccp->hash_delete(this);
+ set_req(MemNode::Control, adr->in(0));
+ ccp->hash_insert(this);
+ return this;
+
+ // List of "safe" opcodes; those that implicitly block the memory
+ // op below any null check.
+ case Op_CastX2P: // no null checks on native pointers
+ case Op_Parm: // 'this' pointer is not null
+ case Op_LoadP: // Loading from within a klass
+ case Op_LoadKlass: // Loading from within a klass
+ case Op_ConP: // Loading from a klass
+ case Op_CreateEx: // Sucking up the guts of an exception oop
+ case Op_Con: // Reading from TLS
+ case Op_CMoveP: // CMoveP is pinned
+ break; // No progress
+
+ case Op_Proj: // Direct call to an allocation routine
+ case Op_SCMemProj: // Memory state from store conditional ops
+#ifdef ASSERT
+ {
+ assert(adr->as_Proj()->_con == TypeFunc::Parms, "must be return value");
+ const Node* call = adr->in(0);
+ if (call->is_CallStaticJava()) {
+ const CallStaticJavaNode* call_java = call->as_CallStaticJava();
+ assert(call_java && call_java->method() == NULL, "must be runtime call");
+ // We further presume that this is one of
+ // new_instance_Java, new_array_Java, or
+ // the like, but do not assert for this.
+ } else if (call->is_Allocate()) {
+ // similar case to new_instance_Java, etc.
+ } else if (!call->is_CallLeaf()) {
+ // Projections from fetch_oop (OSR) are allowed as well.
+ ShouldNotReachHere();
+ }
+ }
+#endif
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+ break;
+ }
+ }
+
+ return NULL; // No progress
+}
+
+
+//=============================================================================
+uint LoadNode::size_of() const { return sizeof(*this); }
+uint LoadNode::cmp( const Node &n ) const
+{ return !Type::cmp( _type, ((LoadNode&)n)._type ); }
+const Type *LoadNode::bottom_type() const { return _type; }
+uint LoadNode::ideal_reg() const {
+ return Matcher::base2reg[_type->base()];
+}
+
+#ifndef PRODUCT
+void LoadNode::dump_spec(outputStream *st) const {
+ MemNode::dump_spec(st);
+ if( !Verbose && !WizardMode ) {
+ // standard dump does this in Verbose and WizardMode
+ st->print(" #"); _type->dump_on(st);
+ }
+}
+#endif
+
+
+//----------------------------LoadNode::make-----------------------------------
+// Polymorphic factory method:
+LoadNode *LoadNode::make( Compile *C, Node *ctl, Node *mem, Node *adr, const TypePtr* adr_type, const Type *rt, BasicType bt ) {
+ // sanity check the alias category against the created node type
+ assert(!(adr_type->isa_oopptr() &&
+ adr_type->offset() == oopDesc::klass_offset_in_bytes()),
+ "use LoadKlassNode instead");
+ assert(!(adr_type->isa_aryptr() &&
+ adr_type->offset() == arrayOopDesc::length_offset_in_bytes()),
+ "use LoadRangeNode instead");
+ switch (bt) {
+ case T_BOOLEAN:
+ case T_BYTE: return new (C, 3) LoadBNode(ctl, mem, adr, adr_type, rt->is_int() );
+ case T_INT: return new (C, 3) LoadINode(ctl, mem, adr, adr_type, rt->is_int() );
+ case T_CHAR: return new (C, 3) LoadCNode(ctl, mem, adr, adr_type, rt->is_int() );
+ case T_SHORT: return new (C, 3) LoadSNode(ctl, mem, adr, adr_type, rt->is_int() );
+ case T_LONG: return new (C, 3) LoadLNode(ctl, mem, adr, adr_type, rt->is_long() );
+ case T_FLOAT: return new (C, 3) LoadFNode(ctl, mem, adr, adr_type, rt );
+ case T_DOUBLE: return new (C, 3) LoadDNode(ctl, mem, adr, adr_type, rt );
+ case T_ADDRESS: return new (C, 3) LoadPNode(ctl, mem, adr, adr_type, rt->is_ptr() );
+ case T_OBJECT: return new (C, 3) LoadPNode(ctl, mem, adr, adr_type, rt->is_oopptr());
+ }
+ ShouldNotReachHere();
+ return (LoadNode*)NULL;
+}
+
+LoadLNode* LoadLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt) {
+ bool require_atomic = true;
+ return new (C, 3) LoadLNode(ctl, mem, adr, adr_type, rt->is_long(), require_atomic);
+}
+
+
+
+
+//------------------------------hash-------------------------------------------
+uint LoadNode::hash() const {
+ // unroll addition of interesting fields
+ return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address);
+}
+
+//---------------------------can_see_stored_value------------------------------
+// This routine exists to make sure this set of tests is done the same
+// everywhere. We need to make a coordinated change: first LoadNode::Ideal
+// will change the graph shape in a way which makes memory alive twice at the
+// same time (uses the Oracle model of aliasing), then some
+// LoadXNode::Identity will fold things back to the equivalence-class model
+// of aliasing.
+Node* MemNode::can_see_stored_value(Node* st, PhaseTransform* phase) const {
+ Node* ld_adr = in(MemNode::Address);
+
+ // Loop around twice in the case Load -> Initialize -> Store.
+ // (See PhaseIterGVN::add_users_to_worklist, which knows about this case.)
+ for (int trip = 0; trip <= 1; trip++) {
+
+ if (st->is_Store()) {
+ Node* st_adr = st->in(MemNode::Address);
+ if (!phase->eqv(st_adr, ld_adr)) {
+ // Try harder before giving up... Match raw and non-raw pointers.
+ intptr_t st_off = 0;
+ AllocateNode* alloc = AllocateNode::Ideal_allocation(st_adr, phase, st_off);
+ if (alloc == NULL) return NULL;
+ intptr_t ld_off = 0;
+ AllocateNode* allo2 = AllocateNode::Ideal_allocation(ld_adr, phase, ld_off);
+ if (alloc != allo2) return NULL;
+ if (ld_off != st_off) return NULL;
+ // At this point we have proven something like this setup:
+ // A = Allocate(...)
+ // L = LoadQ(, AddP(CastPP(, A.Parm),, #Off))
+ // S = StoreQ(, AddP(, A.Parm , #Off), V)
+ // (Actually, we haven't yet proven the Q's are the same.)
+ // In other words, we are loading from a casted version of
+ // the same pointer-and-offset that we stored to.
+ // Thus, we are able to replace L by V.
+ }
+ // Now prove that we have a LoadQ matched to a StoreQ, for some Q.
+ if (store_Opcode() != st->Opcode())
+ return NULL;
+ return st->in(MemNode::ValueIn);
+ }
+
+ intptr_t offset = 0; // scratch
+
+ // A load from a freshly-created object always returns zero.
+ // (This can happen after LoadNode::Ideal resets the load's memory input
+ // to find_captured_store, which returned InitializeNode::zero_memory.)
+ if (st->is_Proj() && st->in(0)->is_Allocate() &&
+ st->in(0) == AllocateNode::Ideal_allocation(ld_adr, phase, offset) &&
+ offset >= st->in(0)->as_Allocate()->minimum_header_size()) {
+ // return a zero value for the load's basic type
+ // (This is one of the few places where a generic PhaseTransform
+ // can create new nodes. Think of it as lazily manifesting
+ // virtually pre-existing constants.)
+ return phase->zerocon(memory_type());
+ }
+
+ // A load from an initialization barrier can match a captured store.
+ if (st->is_Proj() && st->in(0)->is_Initialize()) {
+ InitializeNode* init = st->in(0)->as_Initialize();
+ AllocateNode* alloc = init->allocation();
+ if (alloc != NULL &&
+ alloc == AllocateNode::Ideal_allocation(ld_adr, phase, offset)) {
+ // examine a captured store value
+ st = init->find_captured_store(offset, memory_size(), phase);
+ if (st != NULL)
+ continue; // take one more trip around
+ }
+ }
+
+ break;
+ }
+
+ return NULL;
+}
+
+//------------------------------Identity---------------------------------------
+// Loads are identity if previous store is to same address
+Node *LoadNode::Identity( PhaseTransform *phase ) {
+ // If the previous store-maker is the right kind of Store, and the store is
+ // to the same address, then we are equal to the value stored.
+ Node* mem = in(MemNode::Memory);
+ Node* value = can_see_stored_value(mem, phase);
+ if( value ) {
+ // byte, short & char stores truncate naturally.
+ // A load has to load the truncated value which requires
+ // some sort of masking operation and that requires an
+ // Ideal call instead of an Identity call.
+ if (memory_size() < BytesPerInt) {
+ // If the input to the store does not fit with the load's result type,
+ // it must be truncated via an Ideal call.
+ if (!phase->type(value)->higher_equal(phase->type(this)))
+ return this;
+ }
+ // (This works even when value is a Con, but LoadNode::Value
+ // usually runs first, producing the singleton type of the Con.)
+ return value;
+ }
+ return this;
+}
+
+//------------------------------Ideal------------------------------------------
+// If the load is from Field memory and the pointer is non-null, we can
+// zero out the control input.
+// If the offset is constant and the base is an object allocation,
+// try to hook me up to the exact initializing store.
+Node *LoadNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ Node* p = MemNode::Ideal_common(phase, can_reshape);
+ if (p) return (p == NodeSentinel) ? NULL : p;
+
+ Node* ctrl = in(MemNode::Control);
+ Node* address = in(MemNode::Address);
+
+ // Skip up past a SafePoint control. Cannot do this for Stores because
+ // pointer stores & cardmarks must stay on the same side of a SafePoint.
+ if( ctrl != NULL && ctrl->Opcode() == Op_SafePoint &&
+ phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw ) {
+ ctrl = ctrl->in(0);
+ set_req(MemNode::Control,ctrl);
+ }
+
+ // Check for useless control edge in some common special cases
+ if (in(MemNode::Control) != NULL) {
+ intptr_t ignore = 0;
+ Node* base = AddPNode::Ideal_base_and_offset(address, phase, ignore);
+ if (base != NULL
+ && phase->type(base)->higher_equal(TypePtr::NOTNULL)
+ && detect_dominating_control(base->in(0), phase->C->start())) {
+ // A method-invariant, non-null address (constant or 'this' argument).
+ set_req(MemNode::Control, NULL);
+ }
+ }
+
+ // Check for prior store with a different base or offset; make Load
+ // independent. Skip through any number of them. Bail out if the stores
+ // are in an endless dead cycle and report no progress. This is a key
+ // transform for Reflection. However, if after skipping through the Stores
+ // we can't then fold up against a prior store do NOT do the transform as
+ // this amounts to using the 'Oracle' model of aliasing. It leaves the same
+ // array memory alive twice: once for the hoisted Load and again after the
+ // bypassed Store. This situation only works if EVERYBODY who does
+ // anti-dependence work knows how to bypass. I.e. we need all
+ // anti-dependence checks to ask the same Oracle. Right now, that Oracle is
+ // the alias index stuff. So instead, peek through Stores and IFF we can
+ // fold up, do so.
+ Node* prev_mem = find_previous_store(phase);
+ // Steps (a), (b): Walk past independent stores to find an exact match.
+ if (prev_mem != NULL && prev_mem != in(MemNode::Memory)) {
+ // (c) See if we can fold up on the spot, but don't fold up here.
+ // Fold-up might require truncation (for LoadB/LoadS/LoadC) or
+ // just return a prior value, which is done by Identity calls.
+ if (can_see_stored_value(prev_mem, phase)) {
+ // Make ready for step (d):
+ set_req(MemNode::Memory, prev_mem);
+ return this;
+ }
+ }
+
+ return NULL; // No further progress
+}
+
+// Helper to recognize certain Klass fields which are invariant across
+// some group of array types (e.g., int[] or all T[] where T < Object).
+const Type*
+LoadNode::load_array_final_field(const TypeKlassPtr *tkls,
+ ciKlass* klass) const {
+ if (tkls->offset() == Klass::modifier_flags_offset_in_bytes() + (int)sizeof(oopDesc)) {
+ // The field is Klass::_modifier_flags. Return its (constant) value.
+ // (Folds up the 2nd indirection in aClassConstant.getModifiers().)
+ assert(this->Opcode() == Op_LoadI, "must load an int from _modifier_flags");
+ return TypeInt::make(klass->modifier_flags());
+ }
+ if (tkls->offset() == Klass::access_flags_offset_in_bytes() + (int)sizeof(oopDesc)) {
+ // The field is Klass::_access_flags. Return its (constant) value.
+ // (Folds up the 2nd indirection in Reflection.getClassAccessFlags(aClassConstant).)
+ assert(this->Opcode() == Op_LoadI, "must load an int from _access_flags");
+ return TypeInt::make(klass->access_flags());
+ }
+ if (tkls->offset() == Klass::layout_helper_offset_in_bytes() + (int)sizeof(oopDesc)) {
+ // The field is Klass::_layout_helper. Return its constant value if known.
+ assert(this->Opcode() == Op_LoadI, "must load an int from _layout_helper");
+ return TypeInt::make(klass->layout_helper());
+ }
+
+ // No match.
+ return NULL;
+}
+
+//------------------------------Value-----------------------------------------
+const Type *LoadNode::Value( PhaseTransform *phase ) const {
+ // Either input is TOP ==> the result is TOP
+ Node* mem = in(MemNode::Memory);
+ const Type *t1 = phase->type(mem);
+ if (t1 == Type::TOP) return Type::TOP;
+ Node* adr = in(MemNode::Address);
+ const TypePtr* tp = phase->type(adr)->isa_ptr();
+ if (tp == NULL || tp->empty()) return Type::TOP;
+ int off = tp->offset();
+ assert(off != Type::OffsetTop, "case covered by TypePtr::empty");
+
+ // Try to guess loaded type from pointer type
+ if (tp->base() == Type::AryPtr) {
+ const Type *t = tp->is_aryptr()->elem();
+ // Don't do this for integer types. There is only potential profit if
+ // the element type t is lower than _type; that is, for int types, if _type is
+ // more restrictive than t. This only happens here if one is short and the other
+ // char (both 16 bits), and in those cases we've made an intentional decision
+ // to use one kind of load over the other. See AndINode::Ideal and 4965907.
+ // Also, do not try to narrow the type for a LoadKlass, regardless of offset.
+ //
+ // Yes, it is possible to encounter an expression like (LoadKlass p1:(AddP x x 8))
+ // where the _gvn.type of the AddP is wider than 8. This occurs when an earlier
+ // copy p0 of (AddP x x 8) has been proven equal to p1, and the p0 has been
+ // subsumed by p1. If p1 is on the worklist but has not yet been re-transformed,
+ // it is possible that p1 will have a type like Foo*[int+]:NotNull*+any.
+ // In fact, that could have been the original type of p1, and p1 could have
+ // had an original form like p1:(AddP x x (LShiftL quux 3)), where the
+ // expression (LShiftL quux 3) independently optimized to the constant 8.
+ if ((t->isa_int() == NULL) && (t->isa_long() == NULL)
+ && Opcode() != Op_LoadKlass) {
+ // t might actually be lower than _type, if _type is a unique
+ // concrete subclass of abstract class t.
+ // Make sure the reference is not into the header, by comparing
+ // the offset against the offset of the start of the array's data.
+ // Different array types begin at slightly different offsets (12 vs. 16).
+ // We choose T_BYTE as an example base type that is least restrictive
+ // as to alignment, which will therefore produce the smallest
+ // possible base offset.
+ const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE);
+ if ((uint)off >= (uint)min_base_off) { // is the offset beyond the header?
+ const Type* jt = t->join(_type);
+ // In any case, do not allow the join, per se, to empty out the type.
+ if (jt->empty() && !t->empty()) {
+ // This can happen if a interface-typed array narrows to a class type.
+ jt = _type;
+ }
+ return jt;
+ }
+ }
+ } else if (tp->base() == Type::InstPtr) {
+ assert( off != Type::OffsetBot ||
+ // arrays can be cast to Objects
+ tp->is_oopptr()->klass()->is_java_lang_Object() ||
+ // unsafe field access may not have a constant offset
+ phase->C->has_unsafe_access(),
+ "Field accesses must be precise" );
+ // For oop loads, we expect the _type to be precise
+ } else if (tp->base() == Type::KlassPtr) {
+ assert( off != Type::OffsetBot ||
+ // arrays can be cast to Objects
+ tp->is_klassptr()->klass()->is_java_lang_Object() ||
+ // also allow array-loading from the primary supertype
+ // array during subtype checks
+ Opcode() == Op_LoadKlass,
+ "Field accesses must be precise" );
+ // For klass/static loads, we expect the _type to be precise
+ }
+
+ const TypeKlassPtr *tkls = tp->isa_klassptr();
+ if (tkls != NULL && !StressReflectiveCode) {
+ ciKlass* klass = tkls->klass();
+ if (klass->is_loaded() && tkls->klass_is_exact()) {
+ // We are loading a field from a Klass metaobject whose identity
+ // is known at compile time (the type is "exact" or "precise").
+ // Check for fields we know are maintained as constants by the VM.
+ if (tkls->offset() == Klass::super_check_offset_offset_in_bytes() + (int)sizeof(oopDesc)) {
+ // The field is Klass::_super_check_offset. Return its (constant) value.
+ // (Folds up type checking code.)
+ assert(Opcode() == Op_LoadI, "must load an int from _super_check_offset");
+ return TypeInt::make(klass->super_check_offset());
+ }
+ // Compute index into primary_supers array
+ juint depth = (tkls->offset() - (Klass::primary_supers_offset_in_bytes() + (int)sizeof(oopDesc))) / sizeof(klassOop);
+ // Check for overflowing; use unsigned compare to handle the negative case.
+ if( depth < ciKlass::primary_super_limit() ) {
+ // The field is an element of Klass::_primary_supers. Return its (constant) value.
+ // (Folds up type checking code.)
+ assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
+ ciKlass *ss = klass->super_of_depth(depth);
+ return ss ? TypeKlassPtr::make(ss) : TypePtr::NULL_PTR;
+ }
+ const Type* aift = load_array_final_field(tkls, klass);
+ if (aift != NULL) return aift;
+ if (tkls->offset() == in_bytes(arrayKlass::component_mirror_offset()) + (int)sizeof(oopDesc)
+ && klass->is_array_klass()) {
+ // The field is arrayKlass::_component_mirror. Return its (constant) value.
+ // (Folds up aClassConstant.getComponentType, common in Arrays.copyOf.)
+ assert(Opcode() == Op_LoadP, "must load an oop from _component_mirror");
+ return TypeInstPtr::make(klass->as_array_klass()->component_mirror());
+ }
+ if (tkls->offset() == Klass::java_mirror_offset_in_bytes() + (int)sizeof(oopDesc)) {
+ // The field is Klass::_java_mirror. Return its (constant) value.
+ // (Folds up the 2nd indirection in anObjConstant.getClass().)
+ assert(Opcode() == Op_LoadP, "must load an oop from _java_mirror");
+ return TypeInstPtr::make(klass->java_mirror());
+ }
+ }
+
+ // We can still check if we are loading from the primary_supers array at a
+ // shallow enough depth. Even though the klass is not exact, entries less
+ // than or equal to its super depth are correct.
+ if (klass->is_loaded() ) {
+ ciType *inner = klass->klass();
+ while( inner->is_obj_array_klass() )
+ inner = inner->as_obj_array_klass()->base_element_type();
+ if( inner->is_instance_klass() &&
+ !inner->as_instance_klass()->flags().is_interface() ) {
+ // Compute index into primary_supers array
+ juint depth = (tkls->offset() - (Klass::primary_supers_offset_in_bytes() + (int)sizeof(oopDesc))) / sizeof(klassOop);
+ // Check for overflowing; use unsigned compare to handle the negative case.
+ if( depth < ciKlass::primary_super_limit() &&
+ depth <= klass->super_depth() ) { // allow self-depth checks to handle self-check case
+ // The field is an element of Klass::_primary_supers. Return its (constant) value.
+ // (Folds up type checking code.)
+ assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
+ ciKlass *ss = klass->super_of_depth(depth);
+ return ss ? TypeKlassPtr::make(ss) : TypePtr::NULL_PTR;
+ }
+ }
+ }
+
+ // If the type is enough to determine that the thing is not an array,
+ // we can give the layout_helper a positive interval type.
+ // This will help short-circuit some reflective code.
+ if (tkls->offset() == Klass::layout_helper_offset_in_bytes() + (int)sizeof(oopDesc)
+ && !klass->is_array_klass() // not directly typed as an array
+ && !klass->is_interface() // specifically not Serializable & Cloneable
+ && !klass->is_java_lang_Object() // not the supertype of all T[]
+ ) {
+ // Note: When interfaces are reliable, we can narrow the interface
+ // test to (klass != Serializable && klass != Cloneable).
+ assert(Opcode() == Op_LoadI, "must load an int from _layout_helper");
+ jint min_size = Klass::instance_layout_helper(oopDesc::header_size(), false);
+ // The key property of this type is that it folds up tests
+ // for array-ness, since it proves that the layout_helper is positive.
+ // Thus, a generic value like the basic object layout helper works fine.
+ return TypeInt::make(min_size, max_jint, Type::WidenMin);
+ }
+ }
+
+ // If we are loading from a freshly-allocated object, produce a zero,
+ // if the load is provably beyond the header of the object.
+ // (Also allow a variable load from a fresh array to produce zero.)
+ if (ReduceFieldZeroing) {
+ Node* value = can_see_stored_value(mem,phase);
+ if (value != NULL && value->is_Con())
+ return value->bottom_type();
+ }
+
+ return _type;
+}
+
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not? Match only the address.
+uint LoadNode::match_edge(uint idx) const {
+ return idx == MemNode::Address;
+}
+
+//--------------------------LoadBNode::Ideal--------------------------------------
+//
+// If the previous store is to the same address as this load,
+// and the value stored was larger than a byte, replace this load
+// with the value stored truncated to a byte. If no truncation is
+// needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadBNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ Node* mem = in(MemNode::Memory);
+ Node* value = can_see_stored_value(mem,phase);
+ if( value && !phase->type(value)->higher_equal( _type ) ) {
+ Node *result = phase->transform( new (phase->C, 3) LShiftINode(value, phase->intcon(24)) );
+ return new (phase->C, 3) RShiftINode(result, phase->intcon(24));
+ }
+ // Identity call will handle the case where truncation is not needed.
+ return LoadNode::Ideal(phase, can_reshape);
+}
+
+//--------------------------LoadCNode::Ideal--------------------------------------
+//
+// If the previous store is to the same address as this load,
+// and the value stored was larger than a char, replace this load
+// with the value stored truncated to a char. If no truncation is
+// needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadCNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ Node* mem = in(MemNode::Memory);
+ Node* value = can_see_stored_value(mem,phase);
+ if( value && !phase->type(value)->higher_equal( _type ) )
+ return new (phase->C, 3) AndINode(value,phase->intcon(0xFFFF));
+ // Identity call will handle the case where truncation is not needed.
+ return LoadNode::Ideal(phase, can_reshape);
+}
+
+//--------------------------LoadSNode::Ideal--------------------------------------
+//
+// If the previous store is to the same address as this load,
+// and the value stored was larger than a short, replace this load
+// with the value stored truncated to a short. If no truncation is
+// needed, the replacement is done in LoadNode::Identity().
+//
+Node *LoadSNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ Node* mem = in(MemNode::Memory);
+ Node* value = can_see_stored_value(mem,phase);
+ if( value && !phase->type(value)->higher_equal( _type ) ) {
+ Node *result = phase->transform( new (phase->C, 3) LShiftINode(value, phase->intcon(16)) );
+ return new (phase->C, 3) RShiftINode(result, phase->intcon(16));
+ }
+ // Identity call will handle the case where truncation is not needed.
+ return LoadNode::Ideal(phase, can_reshape);
+}
+
+//=============================================================================
+//------------------------------Value------------------------------------------
+const Type *LoadKlassNode::Value( PhaseTransform *phase ) const {
+ // Either input is TOP ==> the result is TOP
+ const Type *t1 = phase->type( in(MemNode::Memory) );
+ if (t1 == Type::TOP) return Type::TOP;
+ Node *adr = in(MemNode::Address);
+ const Type *t2 = phase->type( adr );
+ if (t2 == Type::TOP) return Type::TOP;
+ const TypePtr *tp = t2->is_ptr();
+ if (TypePtr::above_centerline(tp->ptr()) ||
+ tp->ptr() == TypePtr::Null) return Type::TOP;
+
+ // Return a more precise klass, if possible
+ const TypeInstPtr *tinst = tp->isa_instptr();
+ if (tinst != NULL) {
+ ciInstanceKlass* ik = tinst->klass()->as_instance_klass();
+ int offset = tinst->offset();
+ if (ik == phase->C->env()->Class_klass()
+ && (offset == java_lang_Class::klass_offset_in_bytes() ||
+ offset == java_lang_Class::array_klass_offset_in_bytes())) {
+ // We are loading a special hidden field from a Class mirror object,
+ // the field which points to the VM's Klass metaobject.
+ ciType* t = tinst->java_mirror_type();
+ // java_mirror_type returns non-null for compile-time Class constants.
+ if (t != NULL) {
+ // constant oop => constant klass
+ if (offset == java_lang_Class::array_klass_offset_in_bytes()) {
+ return TypeKlassPtr::make(ciArrayKlass::make(t));
+ }
+ if (!t->is_klass()) {
+ // a primitive Class (e.g., int.class) has NULL for a klass field
+ return TypePtr::NULL_PTR;
+ }
+ // (Folds up the 1st indirection in aClassConstant.getModifiers().)
+ return TypeKlassPtr::make(t->as_klass());
+ }
+ // non-constant mirror, so we can't tell what's going on
+ }
+ if( !ik->is_loaded() )
+ return _type; // Bail out if not loaded
+ if (offset == oopDesc::klass_offset_in_bytes()) {
+ if (tinst->klass_is_exact()) {
+ return TypeKlassPtr::make(ik);
+ }
+ // See if we can become precise: no subklasses and no interface
+ // (Note: We need to support verified interfaces.)
+ if (!ik->is_interface() && !ik->has_subklass()) {
+ //assert(!UseExactTypes, "this code should be useless with exact types");
+ // Add a dependence; if any subclass added we need to recompile
+ if (!ik->is_final()) {
+ // %%% should use stronger assert_unique_concrete_subtype instead
+ phase->C->dependencies()->assert_leaf_type(ik);
+ }
+ // Return precise klass
+ return TypeKlassPtr::make(ik);
+ }
+
+ // Return root of possible klass
+ return TypeKlassPtr::make(TypePtr::NotNull, ik, 0/*offset*/);
+ }
+ }
+
+ // Check for loading klass from an array
+ const TypeAryPtr *tary = tp->isa_aryptr();
+ if( tary != NULL ) {
+ ciKlass *tary_klass = tary->klass();
+ if (tary_klass != NULL // can be NULL when at BOTTOM or TOP
+ && tary->offset() == oopDesc::klass_offset_in_bytes()) {
+ if (tary->klass_is_exact()) {
+ return TypeKlassPtr::make(tary_klass);
+ }
+ ciArrayKlass *ak = tary->klass()->as_array_klass();
+ // If the klass is an object array, we defer the question to the
+ // array component klass.
+ if( ak->is_obj_array_klass() ) {
+ assert( ak->is_loaded(), "" );
+ ciKlass *base_k = ak->as_obj_array_klass()->base_element_klass();
+ if( base_k->is_loaded() && base_k->is_instance_klass() ) {
+ ciInstanceKlass* ik = base_k->as_instance_klass();
+ // See if we can become precise: no subklasses and no interface
+ if (!ik->is_interface() && !ik->has_subklass()) {
+ //assert(!UseExactTypes, "this code should be useless with exact types");
+ // Add a dependence; if any subclass added we need to recompile
+ if (!ik->is_final()) {
+ phase->C->dependencies()->assert_leaf_type(ik);
+ }
+ // Return precise array klass
+ return TypeKlassPtr::make(ak);
+ }
+ }
+ return TypeKlassPtr::make(TypePtr::NotNull, ak, 0/*offset*/);
+ } else { // Found a type-array?
+ //assert(!UseExactTypes, "this code should be useless with exact types");
+ assert( ak->is_type_array_klass(), "" );
+ return TypeKlassPtr::make(ak); // These are always precise
+ }
+ }
+ }
+
+ // Check for loading klass from an array klass
+ const TypeKlassPtr *tkls = tp->isa_klassptr();
+ if (tkls != NULL && !StressReflectiveCode) {
+ ciKlass* klass = tkls->klass();
+ if( !klass->is_loaded() )
+ return _type; // Bail out if not loaded
+ if( klass->is_obj_array_klass() &&
+ (uint)tkls->offset() == objArrayKlass::element_klass_offset_in_bytes() + sizeof(oopDesc)) {
+ ciKlass* elem = klass->as_obj_array_klass()->element_klass();
+ // // Always returning precise element type is incorrect,
+ // // e.g., element type could be object and array may contain strings
+ // return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
+
+ // The array's TypeKlassPtr was declared 'precise' or 'not precise'
+ // according to the element type's subclassing.
+ return TypeKlassPtr::make(tkls->ptr(), elem, 0/*offset*/);
+ }
+ if( klass->is_instance_klass() && tkls->klass_is_exact() &&
+ (uint)tkls->offset() == Klass::super_offset_in_bytes() + sizeof(oopDesc)) {
+ ciKlass* sup = klass->as_instance_klass()->super();
+ // The field is Klass::_super. Return its (constant) value.
+ // (Folds up the 2nd indirection in aClassConstant.getSuperClass().)
+ return sup ? TypeKlassPtr::make(sup) : TypePtr::NULL_PTR;
+ }
+ }
+
+ // Bailout case
+ return LoadNode::Value(phase);
+}
+
+//------------------------------Identity---------------------------------------
+// To clean up reflective code, simplify k.java_mirror.as_klass to plain k.
+// Also feed through the klass in Allocate(...klass...)._klass.
+Node* LoadKlassNode::Identity( PhaseTransform *phase ) {
+ Node* x = LoadNode::Identity(phase);
+ if (x != this) return x;
+
+ // Take apart the address into an oop and and offset.
+ // Return 'this' if we cannot.
+ Node* adr = in(MemNode::Address);
+ intptr_t offset = 0;
+ Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+ if (base == NULL) return this;
+ const TypeOopPtr* toop = phase->type(adr)->isa_oopptr();
+ if (toop == NULL) return this;
+
+ // We can fetch the klass directly through an AllocateNode.
+ // This works even if the klass is not constant (clone or newArray).
+ if (offset == oopDesc::klass_offset_in_bytes()) {
+ Node* allocated_klass = AllocateNode::Ideal_klass(base, phase);
+ if (allocated_klass != NULL) {
+ return allocated_klass;
+ }
+ }
+
+ // Simplify k.java_mirror.as_klass to plain k, where k is a klassOop.
+ // Simplify ak.component_mirror.array_klass to plain ak, ak an arrayKlass.
+ // See inline_native_Class_query for occurrences of these patterns.
+ // Java Example: x.getClass().isAssignableFrom(y)
+ // Java Example: Array.newInstance(x.getClass().getComponentType(), n)
+ //
+ // This improves reflective code, often making the Class
+ // mirror go completely dead. (Current exception: Class
+ // mirrors may appear in debug info, but we could clean them out by
+ // introducing a new debug info operator for klassOop.java_mirror).
+ if (toop->isa_instptr() && toop->klass() == phase->C->env()->Class_klass()
+ && (offset == java_lang_Class::klass_offset_in_bytes() ||
+ offset == java_lang_Class::array_klass_offset_in_bytes())) {
+ // We are loading a special hidden field from a Class mirror,
+ // the field which points to its Klass or arrayKlass metaobject.
+ if (base->is_Load()) {
+ Node* adr2 = base->in(MemNode::Address);
+ const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr();
+ if (tkls != NULL && !tkls->empty()
+ && (tkls->klass()->is_instance_klass() ||
+ tkls->klass()->is_array_klass())
+ && adr2->is_AddP()
+ ) {
+ int mirror_field = Klass::java_mirror_offset_in_bytes();
+ if (offset == java_lang_Class::array_klass_offset_in_bytes()) {
+ mirror_field = in_bytes(arrayKlass::component_mirror_offset());
+ }
+ if (tkls->offset() == mirror_field + (int)sizeof(oopDesc)) {
+ return adr2->in(AddPNode::Base);
+ }
+ }
+ }
+ }
+
+ return this;
+}
+
+//------------------------------Value-----------------------------------------
+const Type *LoadRangeNode::Value( PhaseTransform *phase ) const {
+ // Either input is TOP ==> the result is TOP
+ const Type *t1 = phase->type( in(MemNode::Memory) );
+ if( t1 == Type::TOP ) return Type::TOP;
+ Node *adr = in(MemNode::Address);
+ const Type *t2 = phase->type( adr );
+ if( t2 == Type::TOP ) return Type::TOP;
+ const TypePtr *tp = t2->is_ptr();
+ if (TypePtr::above_centerline(tp->ptr())) return Type::TOP;
+ const TypeAryPtr *tap = tp->isa_aryptr();
+ if( !tap ) return _type;
+ return tap->size();
+}
+
+//------------------------------Identity---------------------------------------
+// Feed through the length in AllocateArray(...length...)._length.
+Node* LoadRangeNode::Identity( PhaseTransform *phase ) {
+ Node* x = LoadINode::Identity(phase);
+ if (x != this) return x;
+
+ // Take apart the address into an oop and and offset.
+ // Return 'this' if we cannot.
+ Node* adr = in(MemNode::Address);
+ intptr_t offset = 0;
+ Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
+ if (base == NULL) return this;
+ const TypeAryPtr* tary = phase->type(adr)->isa_aryptr();
+ if (tary == NULL) return this;
+
+ // We can fetch the length directly through an AllocateArrayNode.
+ // This works even if the length is not constant (clone or newArray).
+ if (offset == arrayOopDesc::length_offset_in_bytes()) {
+ Node* allocated_length = AllocateArrayNode::Ideal_length(base, phase);
+ if (allocated_length != NULL) {
+ return allocated_length;
+ }
+ }
+
+ return this;
+
+}
+//=============================================================================
+//---------------------------StoreNode::make-----------------------------------
+// Polymorphic factory method:
+StoreNode* StoreNode::make( Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, BasicType bt ) {
+ switch (bt) {
+ case T_BOOLEAN:
+ case T_BYTE: return new (C, 4) StoreBNode(ctl, mem, adr, adr_type, val);
+ case T_INT: return new (C, 4) StoreINode(ctl, mem, adr, adr_type, val);
+ case T_CHAR:
+ case T_SHORT: return new (C, 4) StoreCNode(ctl, mem, adr, adr_type, val);
+ case T_LONG: return new (C, 4) StoreLNode(ctl, mem, adr, adr_type, val);
+ case T_FLOAT: return new (C, 4) StoreFNode(ctl, mem, adr, adr_type, val);
+ case T_DOUBLE: return new (C, 4) StoreDNode(ctl, mem, adr, adr_type, val);
+ case T_ADDRESS:
+ case T_OBJECT: return new (C, 4) StorePNode(ctl, mem, adr, adr_type, val);
+ }
+ ShouldNotReachHere();
+ return (StoreNode*)NULL;
+}
+
+StoreLNode* StoreLNode::make_atomic(Compile *C, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val) {
+ bool require_atomic = true;
+ return new (C, 4) StoreLNode(ctl, mem, adr, adr_type, val, require_atomic);
+}
+
+
+//--------------------------bottom_type----------------------------------------
+const Type *StoreNode::bottom_type() const {
+ return Type::MEMORY;
+}
+
+//------------------------------hash-------------------------------------------
+uint StoreNode::hash() const {
+ // unroll addition of interesting fields
+ //return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address) + (uintptr_t)in(ValueIn);
+
+ // Since they are not commoned, do not hash them:
+ return NO_HASH;
+}
+
+//------------------------------Ideal------------------------------------------
+// Change back-to-back Store(, p, x) -> Store(m, p, y) to Store(m, p, x).
+// When a store immediately follows a relevant allocation/initialization,
+// try to capture it into the initialization, or hoist it above.
+Node *StoreNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ Node* p = MemNode::Ideal_common(phase, can_reshape);
+ if (p) return (p == NodeSentinel) ? NULL : p;
+
+ Node* mem = in(MemNode::Memory);
+ Node* address = in(MemNode::Address);
+
+ // Back-to-back stores to same address? Fold em up.
+ // Generally unsafe if I have intervening uses...
+ if (mem->is_Store() && phase->eqv_uncast(mem->in(MemNode::Address), address)) {
+ // Looking at a dead closed cycle of memory?
+ assert(mem != mem->in(MemNode::Memory), "dead loop in StoreNode::Ideal");
+
+ assert(Opcode() == mem->Opcode() ||
+ phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw,
+ "no mismatched stores, except on raw memory");
+
+ if (mem->outcnt() == 1 && // check for intervening uses
+ mem->as_Store()->memory_size() <= this->memory_size()) {
+ // If anybody other than 'this' uses 'mem', we cannot fold 'mem' away.
+ // For example, 'mem' might be the final state at a conditional return.
+ // Or, 'mem' might be used by some node which is live at the same time
+ // 'this' is live, which might be unschedulable. So, require exactly
+ // ONE user, the 'this' store, until such time as we clone 'mem' for
+ // each of 'mem's uses (thus making the exactly-1-user-rule hold true).
+ if (can_reshape) { // (%%% is this an anachronism?)
+ set_req_X(MemNode::Memory, mem->in(MemNode::Memory),
+ phase->is_IterGVN());
+ } else {
+ // It's OK to do this in the parser, since DU info is always accurate,
+ // and the parser always refers to nodes via SafePointNode maps.
+ set_req(MemNode::Memory, mem->in(MemNode::Memory));
+ }
+ return this;
+ }
+ }
+
+ // Capture an unaliased, unconditional, simple store into an initializer.
+ // Or, if it is independent of the allocation, hoist it above the allocation.
+ if (ReduceFieldZeroing && /*can_reshape &&*/
+ mem->is_Proj() && mem->in(0)->is_Initialize()) {
+ InitializeNode* init = mem->in(0)->as_Initialize();
+ intptr_t offset = init->can_capture_store(this, phase);
+ if (offset > 0) {
+ Node* moved = init->capture_store(this, offset, phase);
+ // If the InitializeNode captured me, it made a raw copy of me,
+ // and I need to disappear.
+ if (moved != NULL) {
+ // %%% hack to ensure that Ideal returns a new node:
+ mem = MergeMemNode::make(phase->C, mem);
+ return mem; // fold me away
+ }
+ }
+ }
+
+ return NULL; // No further progress
+}
+
+//------------------------------Value-----------------------------------------
+const Type *StoreNode::Value( PhaseTransform *phase ) const {
+ // Either input is TOP ==> the result is TOP
+ const Type *t1 = phase->type( in(MemNode::Memory) );
+ if( t1 == Type::TOP ) return Type::TOP;
+ const Type *t2 = phase->type( in(MemNode::Address) );
+ if( t2 == Type::TOP ) return Type::TOP;
+ const Type *t3 = phase->type( in(MemNode::ValueIn) );
+ if( t3 == Type::TOP ) return Type::TOP;
+ return Type::MEMORY;
+}
+
+//------------------------------Identity---------------------------------------
+// Remove redundant stores:
+// Store(m, p, Load(m, p)) changes to m.
+// Store(, p, x) -> Store(m, p, x) changes to Store(m, p, x).
+Node *StoreNode::Identity( PhaseTransform *phase ) {
+ Node* mem = in(MemNode::Memory);
+ Node* adr = in(MemNode::Address);
+ Node* val = in(MemNode::ValueIn);
+
+ // Load then Store? Then the Store is useless
+ if (val->is_Load() &&
+ phase->eqv_uncast( val->in(MemNode::Address), adr ) &&
+ phase->eqv_uncast( val->in(MemNode::Memory ), mem ) &&
+ val->as_Load()->store_Opcode() == Opcode()) {
+ return mem;
+ }
+
+ // Two stores in a row of the same value?
+ if (mem->is_Store() &&
+ phase->eqv_uncast( mem->in(MemNode::Address), adr ) &&
+ phase->eqv_uncast( mem->in(MemNode::ValueIn), val ) &&
+ mem->Opcode() == Opcode()) {
+ return mem;
+ }
+
+ // Store of zero anywhere into a freshly-allocated object?
+ // Then the store is useless.
+ // (It must already have been captured by the InitializeNode.)
+ if (ReduceFieldZeroing && phase->type(val)->is_zero_type()) {
+ // a newly allocated object is already all-zeroes everywhere
+ if (mem->is_Proj() && mem->in(0)->is_Allocate()) {
+ return mem;
+ }
+
+ // the store may also apply to zero-bits in an earlier object
+ Node* prev_mem = find_previous_store(phase);
+ // Steps (a), (b): Walk past independent stores to find an exact match.
+ if (prev_mem != NULL) {
+ Node* prev_val = can_see_stored_value(prev_mem, phase);
+ if (prev_val != NULL && phase->eqv(prev_val, val)) {
+ // prev_val and val might differ by a cast; it would be good
+ // to keep the more informative of the two.
+ return mem;
+ }
+ }
+ }
+
+ return this;
+}
+
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not? Match only memory & value
+uint StoreNode::match_edge(uint idx) const {
+ return idx == MemNode::Address || idx == MemNode::ValueIn;
+}
+
+//------------------------------cmp--------------------------------------------
+// Do not common stores up together. They generally have to be split
+// back up anyways, so do not bother.
+uint StoreNode::cmp( const Node &n ) const {
+ return (&n == this); // Always fail except on self
+}
+
+//------------------------------Ideal_masked_input-----------------------------
+// Check for a useless mask before a partial-word store
+// (StoreB ... (AndI valIn conIa) )
+// If (conIa & mask == mask) this simplifies to
+// (StoreB ... (valIn) )
+Node *StoreNode::Ideal_masked_input(PhaseGVN *phase, uint mask) {
+ Node *val = in(MemNode::ValueIn);
+ if( val->Opcode() == Op_AndI ) {
+ const TypeInt *t = phase->type( val->in(2) )->isa_int();
+ if( t && t->is_con() && (t->get_con() & mask) == mask ) {
+ set_req(MemNode::ValueIn, val->in(1));
+ return this;
+ }
+ }
+ return NULL;
+}
+
+
+//------------------------------Ideal_sign_extended_input----------------------
+// Check for useless sign-extension before a partial-word store
+// (StoreB ... (RShiftI _ (LShiftI _ valIn conIL ) conIR) )
+// If (conIL == conIR && conIR <= num_bits) this simplifies to
+// (StoreB ... (valIn) )
+Node *StoreNode::Ideal_sign_extended_input(PhaseGVN *phase, int num_bits) {
+ Node *val = in(MemNode::ValueIn);
+ if( val->Opcode() == Op_RShiftI ) {
+ const TypeInt *t = phase->type( val->in(2) )->isa_int();
+ if( t && t->is_con() && (t->get_con() <= num_bits) ) {
+ Node *shl = val->in(1);
+ if( shl->Opcode() == Op_LShiftI ) {
+ const TypeInt *t2 = phase->type( shl->in(2) )->isa_int();
+ if( t2 && t2->is_con() && (t2->get_con() == t->get_con()) ) {
+ set_req(MemNode::ValueIn, shl->in(1));
+ return this;
+ }
+ }
+ }
+ }
+ return NULL;
+}
+
+//------------------------------value_never_loaded-----------------------------------
+// Determine whether there are any possible loads of the value stored.
+// For simplicity, we actually check if there are any loads from the
+// address stored to, not just for loads of the value stored by this node.
+//
+bool StoreNode::value_never_loaded( PhaseTransform *phase) const {
+ Node *adr = in(Address);
+ const TypeOopPtr *adr_oop = phase->type(adr)->isa_oopptr();
+ if (adr_oop == NULL)
+ return false;
+ if (!adr_oop->is_instance())
+ return false; // if not a distinct instance, there may be aliases of the address
+ for (DUIterator_Fast imax, i = adr->fast_outs(imax); i < imax; i++) {
+ Node *use = adr->fast_out(i);
+ int opc = use->Opcode();
+ if (use->is_Load() || use->is_LoadStore()) {
+ return false;
+ }
+ }
+ return true;
+}
+
+//=============================================================================
+//------------------------------Ideal------------------------------------------
+// If the store is from an AND mask that leaves the low bits untouched, then
+// we can skip the AND operation. If the store is from a sign-extension
+// (a left shift, then right shift) we can skip both.
+Node *StoreBNode::Ideal(PhaseGVN *phase, bool can_reshape){
+ Node *progress = StoreNode::Ideal_masked_input(phase, 0xFF);
+ if( progress != NULL ) return progress;
+
+ progress = StoreNode::Ideal_sign_extended_input(phase, 24);
+ if( progress != NULL ) return progress;
+
+ // Finally check the default case
+ return StoreNode::Ideal(phase, can_reshape);
+}
+
+//=============================================================================
+//------------------------------Ideal------------------------------------------
+// If the store is from an AND mask that leaves the low bits untouched, then
+// we can skip the AND operation
+Node *StoreCNode::Ideal(PhaseGVN *phase, bool can_reshape){
+ Node *progress = StoreNode::Ideal_masked_input(phase, 0xFFFF);
+ if( progress != NULL ) return progress;
+
+ progress = StoreNode::Ideal_sign_extended_input(phase, 16);
+ if( progress != NULL ) return progress;
+
+ // Finally check the default case
+ return StoreNode::Ideal(phase, can_reshape);
+}
+
+//=============================================================================
+//------------------------------Identity---------------------------------------
+Node *StoreCMNode::Identity( PhaseTransform *phase ) {
+ // No need to card mark when storing a null ptr
+ Node* my_store = in(MemNode::OopStore);
+ if (my_store->is_Store()) {
+ const Type *t1 = phase->type( my_store->in(MemNode::ValueIn) );
+ if( t1 == TypePtr::NULL_PTR ) {
+ return in(MemNode::Memory);
+ }
+ }
+ return this;
+}
+
+//------------------------------Value-----------------------------------------
+const Type *StoreCMNode::Value( PhaseTransform *phase ) const {
+ // If extra input is TOP ==> the result is TOP
+ const Type *t1 = phase->type( in(MemNode::OopStore) );
+ if( t1 == Type::TOP ) return Type::TOP;
+
+ return StoreNode::Value( phase );
+}
+
+
+//=============================================================================
+//----------------------------------SCMemProjNode------------------------------
+const Type * SCMemProjNode::Value( PhaseTransform *phase ) const
+{
+ return bottom_type();
+}
+
+//=============================================================================
+LoadStoreNode::LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex ) : Node(5) {
+ init_req(MemNode::Control, c );
+ init_req(MemNode::Memory , mem);
+ init_req(MemNode::Address, adr);
+ init_req(MemNode::ValueIn, val);
+ init_req( ExpectedIn, ex );
+ init_class_id(Class_LoadStore);
+
+}
+
+//=============================================================================
+//-------------------------------adr_type--------------------------------------
+// Do we Match on this edge index or not? Do not match memory
+const TypePtr* ClearArrayNode::adr_type() const {
+ Node *adr = in(3);
+ return MemNode::calculate_adr_type(adr->bottom_type());
+}
+
+//------------------------------match_edge-------------------------------------
+// Do we Match on this edge index or not? Do not match memory
+uint ClearArrayNode::match_edge(uint idx) const {
+ return idx > 1;
+}
+
+//------------------------------Identity---------------------------------------
+// Clearing a zero length array does nothing
+Node *ClearArrayNode::Identity( PhaseTransform *phase ) {
+ return phase->type(in(2))->higher_equal(TypeInt::ZERO) ? in(1) : this;
+}
+
+//------------------------------Idealize---------------------------------------
+// Clearing a short array is faster with stores
+Node *ClearArrayNode::Ideal(PhaseGVN *phase, bool can_reshape){
+ const int unit = BytesPerLong;
+ const TypeX* t = phase->type(in(2))->isa_intptr_t();
+ if (!t) return NULL;
+ if (!t->is_con()) return NULL;
+ intptr_t raw_count = t->get_con();
+ intptr_t size = raw_count;
+ if (!Matcher::init_array_count_is_in_bytes) size *= unit;
+ // Clearing nothing uses the Identity call.
+ // Negative clears are possible on dead ClearArrays
+ // (see jck test stmt114.stmt11402.val).
+ if (size <= 0 || size % unit != 0) return NULL;
+ intptr_t count = size / unit;
+ // Length too long; use fast hardware clear
+ if (size > Matcher::init_array_short_size) return NULL;
+ Node *mem = in(1);
+ if( phase->type(mem)==Type::TOP ) return NULL;
+ Node *adr = in(3);
+ const Type* at = phase->type(adr);
+ if( at==Type::TOP ) return NULL;
+ const TypePtr* atp = at->isa_ptr();
+ // adjust atp to be the correct array element address type
+ if (atp == NULL) atp = TypePtr::BOTTOM;
+ else atp = atp->add_offset(Type::OffsetBot);
+ // Get base for derived pointer purposes
+ if( adr->Opcode() != Op_AddP ) Unimplemented();
+ Node *base = adr->in(1);
+
+ Node *zero = phase->makecon(TypeLong::ZERO);
+ Node *off = phase->MakeConX(BytesPerLong);
+ mem = new (phase->C, 4) StoreLNode(in(0),mem,adr,atp,zero);
+ count--;
+ while( count-- ) {
+ mem = phase->transform(mem);
+ adr = phase->transform(new (phase->C, 4) AddPNode(base,adr,off));
+ mem = new (phase->C, 4) StoreLNode(in(0),mem,adr,atp,zero);
+ }
+ return mem;
+}
+
+//----------------------------clear_memory-------------------------------------
+// Generate code to initialize object storage to zero.
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+ intptr_t start_offset,
+ Node* end_offset,
+ PhaseGVN* phase) {
+ Compile* C = phase->C;
+ intptr_t offset = start_offset;
+
+ int unit = BytesPerLong;
+ if ((offset % unit) != 0) {
+ Node* adr = new (C, 4) AddPNode(dest, dest, phase->MakeConX(offset));
+ adr = phase->transform(adr);
+ const TypePtr* atp = TypeRawPtr::BOTTOM;
+ mem = StoreNode::make(C, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT);
+ mem = phase->transform(mem);
+ offset += BytesPerInt;
+ }
+ assert((offset % unit) == 0, "");
+
+ // Initialize the remaining stuff, if any, with a ClearArray.
+ return clear_memory(ctl, mem, dest, phase->MakeConX(offset), end_offset, phase);
+}
+
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+ Node* start_offset,
+ Node* end_offset,
+ PhaseGVN* phase) {
+ Compile* C = phase->C;
+ int unit = BytesPerLong;
+ Node* zbase = start_offset;
+ Node* zend = end_offset;
+
+ // Scale to the unit required by the CPU:
+ if (!Matcher::init_array_count_is_in_bytes) {
+ Node* shift = phase->intcon(exact_log2(unit));
+ zbase = phase->transform( new(C,3) URShiftXNode(zbase, shift) );
+ zend = phase->transform( new(C,3) URShiftXNode(zend, shift) );
+ }
+
+ Node* zsize = phase->transform( new(C,3) SubXNode(zend, zbase) );
+ Node* zinit = phase->zerocon((unit == BytesPerLong) ? T_LONG : T_INT);
+
+ // Bulk clear double-words
+ Node* adr = phase->transform( new(C,4) AddPNode(dest, dest, start_offset) );
+ mem = new (C, 4) ClearArrayNode(ctl, mem, zsize, adr);
+ return phase->transform(mem);
+}
+
+Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
+ intptr_t start_offset,
+ intptr_t end_offset,
+ PhaseGVN* phase) {
+ Compile* C = phase->C;
+ assert((end_offset % BytesPerInt) == 0, "odd end offset");
+ intptr_t done_offset = end_offset;
+ if ((done_offset % BytesPerLong) != 0) {
+ done_offset -= BytesPerInt;
+ }
+ if (done_offset > start_offset) {
+ mem = clear_memory(ctl, mem, dest,
+ start_offset, phase->MakeConX(done_offset), phase);
+ }
+ if (done_offset < end_offset) { // emit the final 32-bit store
+ Node* adr = new (C, 4) AddPNode(dest, dest, phase->MakeConX(done_offset));
+ adr = phase->transform(adr);
+ const TypePtr* atp = TypeRawPtr::BOTTOM;
+ mem = StoreNode::make(C, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT);
+ mem = phase->transform(mem);
+ done_offset += BytesPerInt;
+ }
+ assert(done_offset == end_offset, "");
+ return mem;
+}
+
+//=============================================================================
+// Do we match on this edge? No memory edges
+uint StrCompNode::match_edge(uint idx) const {
+ return idx == 5 || idx == 6;
+}
+
+//------------------------------Ideal------------------------------------------
+// Return a node which is more "ideal" than the current node. Strip out
+// control copies
+Node *StrCompNode::Ideal(PhaseGVN *phase, bool can_reshape){
+ return remove_dead_region(phase, can_reshape) ? this : NULL;
+}
+
+
+//=============================================================================
+MemBarNode::MemBarNode(Compile* C, int alias_idx, Node* precedent)
+ : MultiNode(TypeFunc::Parms + (precedent == NULL? 0: 1)),
+ _adr_type(C->get_adr_type(alias_idx))
+{
+ init_class_id(Class_MemBar);
+ Node* top = C->top();
+ init_req(TypeFunc::I_O,top);
+ init_req(TypeFunc::FramePtr,top);
+ init_req(TypeFunc::ReturnAdr,top);
+ if (precedent != NULL)
+ init_req(TypeFunc::Parms, precedent);
+}
+
+//------------------------------cmp--------------------------------------------
+uint MemBarNode::hash() const { return NO_HASH; }
+uint MemBarNode::cmp( const Node &n ) const {
+ return (&n == this); // Always fail except on self
+}
+
+//------------------------------make-------------------------------------------
+MemBarNode* MemBarNode::make(Compile* C, int opcode, int atp, Node* pn) {
+ int len = Precedent + (pn == NULL? 0: 1);
+ switch (opcode) {
+ case Op_MemBarAcquire: return new(C, len) MemBarAcquireNode(C, atp, pn);
+ case Op_MemBarRelease: return new(C, len) MemBarReleaseNode(C, atp, pn);
+ case Op_MemBarVolatile: return new(C, len) MemBarVolatileNode(C, atp, pn);
+ case Op_MemBarCPUOrder: return new(C, len) MemBarCPUOrderNode(C, atp, pn);
+ case Op_Initialize: return new(C, len) InitializeNode(C, atp, pn);
+ default: ShouldNotReachHere(); return NULL;
+ }
+}
+
+//------------------------------Ideal------------------------------------------
+// Return a node which is more "ideal" than the current node. Strip out
+// control copies
+Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ if (remove_dead_region(phase, can_reshape)) return this;
+ return NULL;
+}
+
+//------------------------------Value------------------------------------------
+const Type *MemBarNode::Value( PhaseTransform *phase ) const {
+ if( !in(0) ) return Type::TOP;
+ if( phase->type(in(0)) == Type::TOP )
+ return Type::TOP;
+ return TypeTuple::MEMBAR;
+}
+
+//------------------------------match------------------------------------------
+// Construct projections for memory.
+Node *MemBarNode::match( const ProjNode *proj, const Matcher *m ) {
+ switch (proj->_con) {
+ case TypeFunc::Control:
+ case TypeFunc::Memory:
+ return new (m->C, 1) MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
+ }
+ ShouldNotReachHere();
+ return NULL;
+}
+
+//===========================InitializeNode====================================
+// SUMMARY:
+// This node acts as a memory barrier on raw memory, after some raw stores.
+// The 'cooked' oop value feeds from the Initialize, not the Allocation.
+// The Initialize can 'capture' suitably constrained stores as raw inits.
+// It can coalesce related raw stores into larger units (called 'tiles').
+// It can avoid zeroing new storage for memory units which have raw inits.
+// At macro-expansion, it is marked 'complete', and does not optimize further.
+//
+// EXAMPLE:
+// The object 'new short[2]' occupies 16 bytes in a 32-bit machine.
+// ctl = incoming control; mem* = incoming memory
+// (Note: A star * on a memory edge denotes I/O and other standard edges.)
+// First allocate uninitialized memory and fill in the header:
+// alloc = (Allocate ctl mem* 16 #short[].klass ...)
+// ctl := alloc.Control; mem* := alloc.Memory*
+// rawmem = alloc.Memory; rawoop = alloc.RawAddress
+// Then initialize to zero the non-header parts of the raw memory block:
+// init = (Initialize alloc.Control alloc.Memory* alloc.RawAddress)
+// ctl := init.Control; mem.SLICE(#short[*]) := init.Memory
+// After the initialize node executes, the object is ready for service:
+// oop := (CheckCastPP init.Control alloc.RawAddress #short[])
+// Suppose its body is immediately initialized as {1,2}:
+// store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
+// store2 = (StoreC init.Control store1 (+ oop 14) 2)
+// mem.SLICE(#short[*]) := store2
+//
+// DETAILS:
+// An InitializeNode collects and isolates object initialization after
+// an AllocateNode and before the next possible safepoint. As a
+// memory barrier (MemBarNode), it keeps critical stores from drifting
+// down past any safepoint or any publication of the allocation.
+// Before this barrier, a newly-allocated object may have uninitialized bits.
+// After this barrier, it may be treated as a real oop, and GC is allowed.
+//
+// The semantics of the InitializeNode include an implicit zeroing of
+// the new object from object header to the end of the object.
+// (The object header and end are determined by the AllocateNode.)
+//
+// Certain stores may be added as direct inputs to the InitializeNode.
+// These stores must update raw memory, and they must be to addresses
+// derived from the raw address produced by AllocateNode, and with
+// a constant offset. They must be ordered by increasing offset.
+// The first one is at in(RawStores), the last at in(req()-1).
+// Unlike most memory operations, they are not linked in a chain,
+// but are displayed in parallel as users of the rawmem output of
+// the allocation.
+//
+// (See comments in InitializeNode::capture_store, which continue
+// the example given above.)
+//
+// When the associated Allocate is macro-expanded, the InitializeNode
+// may be rewritten to optimize collected stores. A ClearArrayNode
+// may also be created at that point to represent any required zeroing.
+// The InitializeNode is then marked 'complete', prohibiting further
+// capturing of nearby memory operations.
+//
+// During macro-expansion, all captured initializations which store
+// constant values of 32 bits or smaller are coalesced (if advantagous)
+// into larger 'tiles' 32 or 64 bits. This allows an object to be
+// initialized in fewer memory operations. Memory words which are
+// covered by neither tiles nor non-constant stores are pre-zeroed
+// by explicit stores of zero. (The code shape happens to do all
+// zeroing first, then all other stores, with both sequences occurring
+// in order of ascending offsets.)
+//
+// Alternatively, code may be inserted between an AllocateNode and its
+// InitializeNode, to perform arbitrary initialization of the new object.
+// E.g., the object copying intrinsics insert complex data transfers here.
+// The initialization must then be marked as 'complete' disable the
+// built-in zeroing semantics and the collection of initializing stores.
+//
+// While an InitializeNode is incomplete, reads from the memory state
+// produced by it are optimizable if they match the control edge and
+// new oop address associated with the allocation/initialization.
+// They return a stored value (if the offset matches) or else zero.
+// A write to the memory state, if it matches control and address,
+// and if it is to a constant offset, may be 'captured' by the
+// InitializeNode. It is cloned as a raw memory operation and rewired
+// inside the initialization, to the raw oop produced by the allocation.
+// Operations on addresses which are provably distinct (e.g., to
+// other AllocateNodes) are allowed to bypass the initialization.
+//
+// The effect of all this is to consolidate object initialization
+// (both arrays and non-arrays, both piecewise and bulk) into a
+// single location, where it can be optimized as a unit.
+//
+// Only stores with an offset less than TrackedInitializationLimit words
+// will be considered for capture by an InitializeNode. This puts a
+// reasonable limit on the complexity of optimized initializations.
+
+//---------------------------InitializeNode------------------------------------
+InitializeNode::InitializeNode(Compile* C, int adr_type, Node* rawoop)
+ : _is_complete(false),
+ MemBarNode(C, adr_type, rawoop)
+{
+ init_class_id(Class_Initialize);
+
+ assert(adr_type == Compile::AliasIdxRaw, "only valid atp");
+ assert(in(RawAddress) == rawoop, "proper init");
+ // Note: allocation() can be NULL, for secondary initialization barriers
+}
+
+// Since this node is not matched, it will be processed by the
+// register allocator. Declare that there are no constraints
+// on the allocation of the RawAddress edge.
+const RegMask &InitializeNode::in_RegMask(uint idx) const {
+ // This edge should be set to top, by the set_complete. But be conservative.
+ if (idx == InitializeNode::RawAddress)
+ return *(Compile::current()->matcher()->idealreg2spillmask[in(idx)->ideal_reg()]);
+ return RegMask::Empty;
+}
+
+Node* InitializeNode::memory(uint alias_idx) {
+ Node* mem = in(Memory);
+ if (mem->is_MergeMem()) {
+ return mem->as_MergeMem()->memory_at(alias_idx);
+ } else {
+ // incoming raw memory is not split
+ return mem;
+ }
+}
+
+bool InitializeNode::is_non_zero() {
+ if (is_complete()) return false;
+ remove_extra_zeroes();
+ return (req() > RawStores);
+}
+
+void InitializeNode::set_complete(PhaseGVN* phase) {
+ assert(!is_complete(), "caller responsibility");
+ _is_complete = true;
+
+ // After this node is complete, it contains a bunch of
+ // raw-memory initializations. There is no need for
+ // it to have anything to do with non-raw memory effects.
+ // Therefore, tell all non-raw users to re-optimize themselves,
+ // after skipping the memory effects of this initialization.
+ PhaseIterGVN* igvn = phase->is_IterGVN();
+ if (igvn) igvn->add_users_to_worklist(this);
+}
+
+// convenience function
+// return false if the init contains any stores already
+bool AllocateNode::maybe_set_complete(PhaseGVN* phase) {
+ InitializeNode* init = initialization();
+ if (init == NULL || init->is_complete()) return false;
+ init->remove_extra_zeroes();
+ // for now, if this allocation has already collected any inits, bail:
+ if (init->is_non_zero()) return false;
+ init->set_complete(phase);
+ return true;
+}
+
+void InitializeNode::remove_extra_zeroes() {
+ if (req() == RawStores) return;
+ Node* zmem = zero_memory();
+ uint fill = RawStores;
+ for (uint i = fill; i < req(); i++) {
+ Node* n = in(i);
+ if (n->is_top() || n == zmem) continue; // skip
+ if (fill < i) set_req(fill, n); // compact
+ ++fill;
+ }
+ // delete any empty spaces created:
+ while (fill < req()) {
+ del_req(fill);
+ }
+}
+
+// Helper for remembering which stores go with which offsets.
+intptr_t InitializeNode::get_store_offset(Node* st, PhaseTransform* phase) {
+ if (!st->is_Store()) return -1; // can happen to dead code via subsume_node
+ intptr_t offset = -1;
+ Node* base = AddPNode::Ideal_base_and_offset(st->in(MemNode::Address),
+ phase, offset);
+ if (base == NULL) return -1; // something is dead,
+ if (offset < 0) return -1; // dead, dead
+ return offset;
+}
+
+// Helper for proving that an initialization expression is
+// "simple enough" to be folded into an object initialization.
+// Attempts to prove that a store's initial value 'n' can be captured
+// within the initialization without creating a vicious cycle, such as:
+// { Foo p = new Foo(); p.next = p; }
+// True for constants and parameters and small combinations thereof.
+bool InitializeNode::detect_init_independence(Node* n,
+ bool st_is_pinned,
+ int& count) {
+ if (n == NULL) return true; // (can this really happen?)
+ if (n->is_Proj()) n = n->in(0);
+ if (n == this) return false; // found a cycle
+ if (n->is_Con()) return true;
+ if (n->is_Start()) return true; // params, etc., are OK
+ if (n->is_Root()) return true; // even better
+
+ Node* ctl = n->in(0);
+ if (ctl != NULL && !ctl->is_top()) {
+ if (ctl->is_Proj()) ctl = ctl->in(0);
+ if (ctl == this) return false;
+
+ // If we already know that the enclosing memory op is pinned right after
+ // the init, then any control flow that the store has picked up
+ // must have preceded the init, or else be equal to the init.
+ // Even after loop optimizations (which might change control edges)
+ // a store is never pinned *before* the availability of its inputs.
+ if (!MemNode::detect_dominating_control(ctl, this->in(0)))
+ return false; // failed to prove a good control
+
+ }
+
+ // Check data edges for possible dependencies on 'this'.
+ if ((count += 1) > 20) return false; // complexity limit
+ for (uint i = 1; i < n->req(); i++) {
+ Node* m = n->in(i);
+ if (m == NULL || m == n || m->is_top()) continue;
+ uint first_i = n->find_edge(m);
+ if (i != first_i) continue; // process duplicate edge just once
+ if (!detect_init_independence(m, st_is_pinned, count)) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+// Here are all the checks a Store must pass before it can be moved into
+// an initialization. Returns zero if a check fails.
+// On success, returns the (constant) offset to which the store applies,
+// within the initialized memory.
+intptr_t InitializeNode::can_capture_store(StoreNode* st, PhaseTransform* phase) {
+ const int FAIL = 0;
+ if (st->req() != MemNode::ValueIn + 1)
+ return FAIL; // an inscrutable StoreNode (card mark?)
+ Node* ctl = st->in(MemNode::Control);
+ if (!(ctl != NULL && ctl->is_Proj() && ctl->in(0) == this))
+ return FAIL; // must be unconditional after the initialization
+ Node* mem = st->in(MemNode::Memory);
+ if (!(mem->is_Proj() && mem->in(0) == this))
+ return FAIL; // must not be preceded by other stores
+ Node* adr = st->in(MemNode::Address);
+ intptr_t offset;
+ AllocateNode* alloc = AllocateNode::Ideal_allocation(adr, phase, offset);
+ if (alloc == NULL)
+ return FAIL; // inscrutable address
+ if (alloc != allocation())
+ return FAIL; // wrong allocation! (store needs to float up)
+ Node* val = st->in(MemNode::ValueIn);
+ int complexity_count = 0;
+ if (!detect_init_independence(val, true, complexity_count))
+ return FAIL; // stored value must be 'simple enough'
+
+ return offset; // success
+}
+
+// Find the captured store in(i) which corresponds to the range
+// [start..start+size) in the initialized object.
+// If there is one, return its index i. If there isn't, return the
+// negative of the index where it should be inserted.
+// Return 0 if the queried range overlaps an initialization boundary
+// or if dead code is encountered.
+// If size_in_bytes is zero, do not bother with overlap checks.
+int InitializeNode::captured_store_insertion_point(intptr_t start,
+ int size_in_bytes,
+ PhaseTransform* phase) {
+ const int FAIL = 0, MAX_STORE = BytesPerLong;
+
+ if (is_complete())
+ return FAIL; // arraycopy got here first; punt
+
+ assert(allocation() != NULL, "must be present");
+
+ // no negatives, no header fields:
+ if (start < (intptr_t) sizeof(oopDesc)) return FAIL;
+ if (start < (intptr_t) sizeof(arrayOopDesc) &&
+ start < (intptr_t) allocation()->minimum_header_size()) return FAIL;
+
+ // after a certain size, we bail out on tracking all the stores:
+ intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
+ if (start >= ti_limit) return FAIL;
+
+ for (uint i = InitializeNode::RawStores, limit = req(); ; ) {
+ if (i >= limit) return -(int)i; // not found; here is where to put it
+
+ Node* st = in(i);
+ intptr_t st_off = get_store_offset(st, phase);
+ if (st_off < 0) {
+ if (st != zero_memory()) {
+ return FAIL; // bail out if there is dead garbage
+ }
+ } else if (st_off > start) {
+ // ...we are done, since stores are ordered
+ if (st_off < start + size_in_bytes) {
+ return FAIL; // the next store overlaps
+ }
+ return -(int)i; // not found; here is where to put it
+ } else if (st_off < start) {
+ if (size_in_bytes != 0 &&
+ start < st_off + MAX_STORE &&
+ start < st_off + st->as_Store()->memory_size()) {
+ return FAIL; // the previous store overlaps
+ }
+ } else {
+ if (size_in_bytes != 0 &&
+ st->as_Store()->memory_size() != size_in_bytes) {
+ return FAIL; // mismatched store size
+ }
+ return i;
+ }
+
+ ++i;
+ }
+}
+
+// Look for a captured store which initializes at the offset 'start'
+// with the given size. If there is no such store, and no other
+// initialization interferes, then return zero_memory (the memory
+// projection of the AllocateNode).
+Node* InitializeNode::find_captured_store(intptr_t start, int size_in_bytes,
+ PhaseTransform* phase) {
+ assert(stores_are_sane(phase), "");
+ int i = captured_store_insertion_point(start, size_in_bytes, phase);
+ if (i == 0) {
+ return NULL; // something is dead
+ } else if (i < 0) {
+ return zero_memory(); // just primordial zero bits here
+ } else {
+ Node* st = in(i); // here is the store at this position
+ assert(get_store_offset(st->as_Store(), phase) == start, "sanity");
+ return st;
+ }
+}
+
+// Create, as a raw pointer, an address within my new object at 'offset'.
+Node* InitializeNode::make_raw_address(intptr_t offset,
+ PhaseTransform* phase) {
+ Node* addr = in(RawAddress);
+ if (offset != 0) {
+ Compile* C = phase->C;
+ addr = phase->transform( new (C, 4) AddPNode(C->top(), addr,
+ phase->MakeConX(offset)) );
+ }
+ return addr;
+}
+
+// Clone the given store, converting it into a raw store
+// initializing a field or element of my new object.
+// Caller is responsible for retiring the original store,
+// with subsume_node or the like.
+//
+// From the example above InitializeNode::InitializeNode,
+// here are the old stores to be captured:
+// store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
+// store2 = (StoreC init.Control store1 (+ oop 14) 2)
+//
+// Here is the changed code; note the extra edges on init:
+// alloc = (Allocate ...)
+// rawoop = alloc.RawAddress
+// rawstore1 = (StoreC alloc.Control alloc.Memory (+ rawoop 12) 1)
+// rawstore2 = (StoreC alloc.Control alloc.Memory (+ rawoop 14) 2)
+// init = (Initialize alloc.Control alloc.Memory rawoop
+// rawstore1 rawstore2)
+//
+Node* InitializeNode::capture_store(StoreNode* st, intptr_t start,
+ PhaseTransform* phase) {
+ assert(stores_are_sane(phase), "");
+
+ if (start < 0) return NULL;
+ assert(can_capture_store(st, phase) == start, "sanity");
+
+ Compile* C = phase->C;
+ int size_in_bytes = st->memory_size();
+ int i = captured_store_insertion_point(start, size_in_bytes, phase);
+ if (i == 0) return NULL; // bail out
+ Node* prev_mem = NULL; // raw memory for the captured store
+ if (i > 0) {
+ prev_mem = in(i); // there is a pre-existing store under this one
+ set_req(i, C->top()); // temporarily disconnect it
+ // See StoreNode::Ideal 'st->outcnt() == 1' for the reason to disconnect.
+ } else {
+ i = -i; // no pre-existing store
+ prev_mem = zero_memory(); // a slice of the newly allocated object
+ if (i > InitializeNode::RawStores && in(i-1) == prev_mem)
+ set_req(--i, C->top()); // reuse this edge; it has been folded away
+ else
+ ins_req(i, C->top()); // build a new edge
+ }
+ Node* new_st = st->clone();
+ new_st->set_req(MemNode::Control, in(Control));
+ new_st->set_req(MemNode::Memory, prev_mem);
+ new_st->set_req(MemNode::Address, make_raw_address(start, phase));
+ new_st = phase->transform(new_st);
+
+ // At this point, new_st might have swallowed a pre-existing store
+ // at the same offset, or perhaps new_st might have disappeared,
+ // if it redundantly stored the same value (or zero to fresh memory).
+
+ // In any case, wire it in:
+ set_req(i, new_st);
+
+ // The caller may now kill the old guy.
+ DEBUG_ONLY(Node* check_st = find_captured_store(start, size_in_bytes, phase));
+ assert(check_st == new_st || check_st == NULL, "must be findable");
+ assert(!is_complete(), "");
+ return new_st;
+}
+
+static bool store_constant(jlong* tiles, int num_tiles,
+ intptr_t st_off, int st_size,
+ jlong con) {
+ if ((st_off & (st_size-1)) != 0)
+ return false; // strange store offset (assume size==2**N)
+ address addr = (address)tiles + st_off;
+ assert(st_off >= 0 && addr+st_size <= (address)&tiles[num_tiles], "oob");
+ switch (st_size) {
+ case sizeof(jbyte): *(jbyte*) addr = (jbyte) con; break;
+ case sizeof(jchar): *(jchar*) addr = (jchar) con; break;
+ case sizeof(jint): *(jint*) addr = (jint) con; break;
+ case sizeof(jlong): *(jlong*) addr = (jlong) con; break;
+ default: return false; // strange store size (detect size!=2**N here)
+ }
+ return true; // return success to caller
+}
+
+// Coalesce subword constants into int constants and possibly
+// into long constants. The goal, if the CPU permits,
+// is to initialize the object with a small number of 64-bit tiles.
+// Also, convert floating-point constants to bit patterns.
+// Non-constants are not relevant to this pass.
+//
+// In terms of the running example on InitializeNode::InitializeNode
+// and InitializeNode::capture_store, here is the transformation
+// of rawstore1 and rawstore2 into rawstore12:
+// alloc = (Allocate ...)
+// rawoop = alloc.RawAddress
+// tile12 = 0x00010002
+// rawstore12 = (StoreI alloc.Control alloc.Memory (+ rawoop 12) tile12)
+// init = (Initialize alloc.Control alloc.Memory rawoop rawstore12)
+//
+void
+InitializeNode::coalesce_subword_stores(intptr_t header_size,
+ Node* size_in_bytes,
+ PhaseGVN* phase) {
+ Compile* C = phase->C;
+
+ assert(stores_are_sane(phase), "");
+ // Note: After this pass, they are not completely sane,
+ // since there may be some overlaps.
+
+ int old_subword = 0, old_long = 0, new_int = 0, new_long = 0;
+
+ intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
+ intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, ti_limit);
+ size_limit = MIN2(size_limit, ti_limit);
+ size_limit = align_size_up(size_limit, BytesPerLong);
+ int num_tiles = size_limit / BytesPerLong;
+
+ // allocate space for the tile map:
+ const int small_len = DEBUG_ONLY(true ? 3 :) 30; // keep stack frames small
+ jlong tiles_buf[small_len];
+ Node* nodes_buf[small_len];
+ jlong inits_buf[small_len];
+ jlong* tiles = ((num_tiles <= small_len) ? &tiles_buf[0]
+ : NEW_RESOURCE_ARRAY(jlong, num_tiles));
+ Node** nodes = ((num_tiles <= small_len) ? &nodes_buf[0]
+ : NEW_RESOURCE_ARRAY(Node*, num_tiles));
+ jlong* inits = ((num_tiles <= small_len) ? &inits_buf[0]
+ : NEW_RESOURCE_ARRAY(jlong, num_tiles));
+ // tiles: exact bitwise model of all primitive constants
+ // nodes: last constant-storing node subsumed into the tiles model
+ // inits: which bytes (in each tile) are touched by any initializations
+
+ //// Pass A: Fill in the tile model with any relevant stores.
+
+ Copy::zero_to_bytes(tiles, sizeof(tiles[0]) * num_tiles);
+ Copy::zero_to_bytes(nodes, sizeof(nodes[0]) * num_tiles);
+ Copy::zero_to_bytes(inits, sizeof(inits[0]) * num_tiles);
+ Node* zmem = zero_memory(); // initially zero memory state
+ for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
+ Node* st = in(i);
+ intptr_t st_off = get_store_offset(st, phase);
+
+ // Figure out the store's offset and constant value:
+ if (st_off < header_size) continue; //skip (ignore header)
+ if (st->in(MemNode::Memory) != zmem) continue; //skip (odd store chain)
+ int st_size = st->as_Store()->memory_size();
+ if (st_off + st_size > size_limit) break;
+
+ // Record which bytes are touched, whether by constant or not.
+ if (!store_constant(inits, num_tiles, st_off, st_size, (jlong) -1))
+ continue; // skip (strange store size)
+
+ const Type* val = phase->type(st->in(MemNode::ValueIn));
+ if (!val->singleton()) continue; //skip (non-con store)
+ BasicType type = val->basic_type();
+
+ jlong con = 0;
+ switch (type) {
+ case T_INT: con = val->is_int()->get_con(); break;
+ case T_LONG: con = val->is_long()->get_con(); break;
+ case T_FLOAT: con = jint_cast(val->getf()); break;
+ case T_DOUBLE: con = jlong_cast(val->getd()); break;
+ default: continue; //skip (odd store type)
+ }
+
+ if (type == T_LONG && Matcher::isSimpleConstant64(con) &&
+ st->Opcode() == Op_StoreL) {
+ continue; // This StoreL is already optimal.
+ }
+
+ // Store down the constant.
+ store_constant(tiles, num_tiles, st_off, st_size, con);
+
+ intptr_t j = st_off >> LogBytesPerLong;
+
+ if (type == T_INT && st_size == BytesPerInt
+ && (st_off & BytesPerInt) == BytesPerInt) {
+ jlong lcon = tiles[j];
+ if (!Matcher::isSimpleConstant64(lcon) &&
+ st->Opcode() == Op_StoreI) {
+ // This StoreI is already optimal by itself.
+ jint* intcon = (jint*) &tiles[j];
+ intcon[1] = 0; // undo the store_constant()
+
+ // If the previous store is also optimal by itself, back up and
+ // undo the action of the previous loop iteration... if we can.
+ // But if we can't, just let the previous half take care of itself.
+ st = nodes[j];
+ st_off -= BytesPerInt;
+ con = intcon[0];
+ if (con != 0 && st != NULL && st->Opcode() == Op_StoreI) {
+ assert(st_off >= header_size, "still ignoring header");
+ assert(get_store_offset(st, phase) == st_off, "must be");
+ assert(in(i-1) == zmem, "must be");
+ DEBUG_ONLY(const Type* tcon = phase->type(st->in(MemNode::ValueIn)));
+ assert(con == tcon->is_int()->get_con(), "must be");
+ // Undo the effects of the previous loop trip, which swallowed st:
+ intcon[0] = 0; // undo store_constant()
+ set_req(i-1, st); // undo set_req(i, zmem)
+ nodes[j] = NULL; // undo nodes[j] = st
+ --old_subword; // undo ++old_subword
+ }
+ continue; // This StoreI is already optimal.
+ }
+ }
+
+ // This store is not needed.
+ set_req(i, zmem);
+ nodes[j] = st; // record for the moment
+ if (st_size < BytesPerLong) // something has changed
+ ++old_subword; // includes int/float, but who's counting...
+ else ++old_long;
+ }
+
+ if ((old_subword + old_long) == 0)
+ return; // nothing more to do
+
+ //// Pass B: Convert any non-zero tiles into optimal constant stores.
+ // Be sure to insert them before overlapping non-constant stores.
+ // (E.g., byte[] x = { 1,2,y,4 } => x[int 0] = 0x01020004, x[2]=y.)
+ for (int j = 0; j < num_tiles; j++) {
+ jlong con = tiles[j];
+ jlong init = inits[j];
+ if (con == 0) continue;
+ jint con0, con1; // split the constant, address-wise
+ jint init0, init1; // split the init map, address-wise
+ { union { jlong con; jint intcon[2]; } u;
+ u.con = con;
+ con0 = u.intcon[0];
+ con1 = u.intcon[1];
+ u.con = init;
+ init0 = u.intcon[0];
+ init1 = u.intcon[1];
+ }
+
+ Node* old = nodes[j];
+ assert(old != NULL, "need the prior store");
+ intptr_t offset = (j * BytesPerLong);
+
+ bool split = !Matcher::isSimpleConstant64(con);
+
+ if (offset < header_size) {
+ assert(offset + BytesPerInt >= header_size, "second int counts");
+ assert(*(jint*)&tiles[j] == 0, "junk in header");
+ split = true; // only the second word counts
+ // Example: int a[] = { 42 ... }
+ } else if (con0 == 0 && init0 == -1) {
+ split = true; // first word is covered by full inits
+ // Example: int a[] = { ... foo(), 42 ... }
+ } else if (con1 == 0 && init1 == -1) {
+ split = true; // second word is covered by full inits
+ // Example: int a[] = { ... 42, foo() ... }
+ }
+
+ // Here's a case where init0 is neither 0 nor -1:
+ // byte a[] = { ... 0,0,foo(),0, 0,0,0,42 ... }
+ // Assuming big-endian memory, init0, init1 are 0x0000FF00, 0x000000FF.
+ // In this case the tile is not split; it is (jlong)42.
+ // The big tile is stored down, and then the foo() value is inserted.
+ // (If there were foo(),foo() instead of foo(),0, init0 would be -1.)
+
+ Node* ctl = old->in(MemNode::Control);
+ Node* adr = make_raw_address(offset, phase);
+ const TypePtr* atp = TypeRawPtr::BOTTOM;
+
+ // One or two coalesced stores to plop down.
+ Node* st[2];
+ intptr_t off[2];
+ int nst = 0;
+ if (!split) {
+ ++new_long;
+ off[nst] = offset;
+ st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+ phase->longcon(con), T_LONG);
+ } else {
+ // Omit either if it is a zero.
+ if (con0 != 0) {
+ ++new_int;
+ off[nst] = offset;
+ st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+ phase->intcon(con0), T_INT);
+ }
+ if (con1 != 0) {
+ ++new_int;
+ offset += BytesPerInt;
+ adr = make_raw_address(offset, phase);
+ off[nst] = offset;
+ st[nst++] = StoreNode::make(C, ctl, zmem, adr, atp,
+ phase->intcon(con1), T_INT);
+ }
+ }
+
+ // Insert second store first, then the first before the second.
+ // Insert each one just before any overlapping non-constant stores.
+ while (nst > 0) {
+ Node* st1 = st[--nst];
+ C->copy_node_notes_to(st1, old);
+ st1 = phase->transform(st1);
+ offset = off[nst];
+ assert(offset >= header_size, "do not smash header");
+ int ins_idx = captured_store_insertion_point(offset, /*size:*/0, phase);
+ guarantee(ins_idx != 0, "must re-insert constant store");
+ if (ins_idx < 0) ins_idx = -ins_idx; // never overlap
+ if (ins_idx > InitializeNode::RawStores && in(ins_idx-1) == zmem)
+ set_req(--ins_idx, st1);
+ else
+ ins_req(ins_idx, st1);
+ }
+ }
+
+ if (PrintCompilation && WizardMode)
+ tty->print_cr("Changed %d/%d subword/long constants into %d/%d int/long",
+ old_subword, old_long, new_int, new_long);
+ if (C->log() != NULL)
+ C->log()->elem("comment that='%d/%d subword/long to %d/%d int/long'",
+ old_subword, old_long, new_int, new_long);
+
+ // Clean up any remaining occurrences of zmem:
+ remove_extra_zeroes();
+}
+
+// Explore forward from in(start) to find the first fully initialized
+// word, and return its offset. Skip groups of subword stores which
+// together initialize full words. If in(start) is itself part of a
+// fully initialized word, return the offset of in(start). If there
+// are no following full-word stores, or if something is fishy, return
+// a negative value.
+intptr_t InitializeNode::find_next_fullword_store(uint start, PhaseGVN* phase) {
+ int int_map = 0;
+ intptr_t int_map_off = 0;
+ const int FULL_MAP = right_n_bits(BytesPerInt); // the int_map we hope for
+
+ for (uint i = start, limit = req(); i < limit; i++) {
+ Node* st = in(i);
+
+ intptr_t st_off = get_store_offset(st, phase);
+ if (st_off < 0) break; // return conservative answer
+
+ int st_size = st->as_Store()->memory_size();
+ if (st_size >= BytesPerInt && (st_off % BytesPerInt) == 0) {
+ return st_off; // we found a complete word init
+ }
+
+ // update the map:
+
+ intptr_t this_int_off = align_size_down(st_off, BytesPerInt);
+ if (this_int_off != int_map_off) {
+ // reset the map:
+ int_map = 0;
+ int_map_off = this_int_off;
+ }
+
+ int subword_off = st_off - this_int_off;
+ int_map |= right_n_bits(st_size) << subword_off;
+ if ((int_map & FULL_MAP) == FULL_MAP) {
+ return this_int_off; // we found a complete word init
+ }
+
+ // Did this store hit or cross the word boundary?
+ intptr_t next_int_off = align_size_down(st_off + st_size, BytesPerInt);
+ if (next_int_off == this_int_off + BytesPerInt) {
+ // We passed the current int, without fully initializing it.
+ int_map_off = next_int_off;
+ int_map >>= BytesPerInt;
+ } else if (next_int_off > this_int_off + BytesPerInt) {
+ // We passed the current and next int.
+ return this_int_off + BytesPerInt;
+ }
+ }
+
+ return -1;
+}
+
+
+// Called when the associated AllocateNode is expanded into CFG.
+// At this point, we may perform additional optimizations.
+// Linearize the stores by ascending offset, to make memory
+// activity as coherent as possible.
+Node* InitializeNode::complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
+ intptr_t header_size,
+ Node* size_in_bytes,
+ PhaseGVN* phase) {
+ assert(!is_complete(), "not already complete");
+ assert(stores_are_sane(phase), "");
+ assert(allocation() != NULL, "must be present");
+
+ remove_extra_zeroes();
+
+ if (ReduceFieldZeroing || ReduceBulkZeroing)
+ // reduce instruction count for common initialization patterns
+ coalesce_subword_stores(header_size, size_in_bytes, phase);
+
+ Node* zmem = zero_memory(); // initially zero memory state
+ Node* inits = zmem; // accumulating a linearized chain of inits
+ #ifdef ASSERT
+ intptr_t last_init_off = sizeof(oopDesc); // previous init offset
+ intptr_t last_init_end = sizeof(oopDesc); // previous init offset+size
+ intptr_t last_tile_end = sizeof(oopDesc); // previous tile offset+size
+ #endif
+ intptr_t zeroes_done = header_size;
+
+ bool do_zeroing = true; // we might give up if inits are very sparse
+ int big_init_gaps = 0; // how many large gaps have we seen?
+
+ if (ZeroTLAB) do_zeroing = false;
+ if (!ReduceFieldZeroing && !ReduceBulkZeroing) do_zeroing = false;
+
+ for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
+ Node* st = in(i);
+ intptr_t st_off = get_store_offset(st, phase);
+ if (st_off < 0)
+ break; // unknown junk in the inits
+ if (st->in(MemNode::Memory) != zmem)
+ break; // complicated store chains somehow in list
+
+ int st_size = st->as_Store()->memory_size();
+ intptr_t next_init_off = st_off + st_size;
+
+ if (do_zeroing && zeroes_done < next_init_off) {
+ // See if this store needs a zero before it or under it.
+ intptr_t zeroes_needed = st_off;
+
+ if (st_size < BytesPerInt) {
+ // Look for subword stores which only partially initialize words.
+ // If we find some, we must lay down some word-level zeroes first,
+ // underneath the subword stores.
+ //
+ // Examples:
+ // byte[] a = { p,q,r,s } => a[0]=p,a[1]=q,a[2]=r,a[3]=s
+ // byte[] a = { x,y,0,0 } => a[0..3] = 0, a[0]=x,a[1]=y
+ // byte[] a = { 0,0,z,0 } => a[0..3] = 0, a[2]=z
+ //
+ // Note: coalesce_subword_stores may have already done this,
+ // if it was prompted by constant non-zero subword initializers.
+ // But this case can still arise with non-constant stores.
+
+ intptr_t next_full_store = find_next_fullword_store(i, phase);
+
+ // In the examples above:
+ // in(i) p q r s x y z
+ // st_off 12 13 14 15 12 13 14
+ // st_size 1 1 1 1 1 1 1
+ // next_full_s. 12 16 16 16 16 16 16
+ // z's_done 12 16 16 16 12 16 12
+ // z's_needed 12 16 16 16 16 16 16
+ // zsize 0 0 0 0 4 0 4
+ if (next_full_store < 0) {
+ // Conservative tack: Zero to end of current word.
+ zeroes_needed = align_size_up(zeroes_needed, BytesPerInt);
+ } else {
+ // Zero to beginning of next fully initialized word.
+ // Or, don't zero at all, if we are already in that word.
+ assert(next_full_store >= zeroes_needed, "must go forward");
+ assert((next_full_store & (BytesPerInt-1)) == 0, "even boundary");
+ zeroes_needed = next_full_store;
+ }
+ }
+
+ if (zeroes_needed > zeroes_done) {
+ intptr_t zsize = zeroes_needed - zeroes_done;
+ // Do some incremental zeroing on rawmem, in parallel with inits.
+ zeroes_done = align_size_down(zeroes_done, BytesPerInt);
+ rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
+ zeroes_done, zeroes_needed,
+ phase);
+ zeroes_done = zeroes_needed;
+ if (zsize > Matcher::init_array_short_size && ++big_init_gaps > 2)
+ do_zeroing = false; // leave the hole, next time
+ }
+ }
+
+ // Collect the store and move on:
+ st->set_req(MemNode::Memory, inits);
+ inits = st; // put it on the linearized chain
+ set_req(i, zmem); // unhook from previous position
+
+ if (zeroes_done == st_off)
+ zeroes_done = next_init_off;
+
+ assert(!do_zeroing || zeroes_done >= next_init_off, "don't miss any");
+
+ #ifdef ASSERT
+ // Various order invariants. Weaker than stores_are_sane because
+ // a large constant tile can be filled in by smaller non-constant stores.
+ assert(st_off >= last_init_off, "inits do not reverse");
+ last_init_off = st_off;
+ const Type* val = NULL;
+ if (st_size >= BytesPerInt &&
+ (val = phase->type(st->in(MemNode::ValueIn)))->singleton() &&
+ (int)val->basic_type() < (int)T_OBJECT) {
+ assert(st_off >= last_tile_end, "tiles do not overlap");
+ assert(st_off >= last_init_end, "tiles do not overwrite inits");
+ last_tile_end = MAX2(last_tile_end, next_init_off);
+ } else {
+ intptr_t st_tile_end = align_size_up(next_init_off, BytesPerLong);
+ assert(st_tile_end >= last_tile_end, "inits stay with tiles");
+ assert(st_off >= last_init_end, "inits do not overlap");
+ last_init_end = next_init_off; // it's a non-tile
+ }
+ #endif //ASSERT
+ }
+
+ remove_extra_zeroes(); // clear out all the zmems left over
+ add_req(inits);
+
+ if (!ZeroTLAB) {
+ // If anything remains to be zeroed, zero it all now.
+ zeroes_done = align_size_down(zeroes_done, BytesPerInt);
+ // if it is the last unused 4 bytes of an instance, forget about it
+ intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, max_jint);
+ if (zeroes_done + BytesPerLong >= size_limit) {
+ assert(allocation() != NULL, "");
+ Node* klass_node = allocation()->in(AllocateNode::KlassNode);
+ ciKlass* k = phase->type(klass_node)->is_klassptr()->klass();
+ if (zeroes_done == k->layout_helper())
+ zeroes_done = size_limit;
+ }
+ if (zeroes_done < size_limit) {
+ rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
+ zeroes_done, size_in_bytes, phase);
+ }
+ }
+
+ set_complete(phase);
+ return rawmem;
+}
+
+
+#ifdef ASSERT
+bool InitializeNode::stores_are_sane(PhaseTransform* phase) {
+ if (is_complete())
+ return true; // stores could be anything at this point
+ intptr_t last_off = sizeof(oopDesc);
+ for (uint i = InitializeNode::RawStores; i < req(); i++) {
+ Node* st = in(i);
+ intptr_t st_off = get_store_offset(st, phase);
+ if (st_off < 0) continue; // ignore dead garbage
+ if (last_off > st_off) {
+ tty->print_cr("*** bad store offset at %d: %d > %d", i, last_off, st_off);
+ this->dump(2);
+ assert(false, "ascending store offsets");
+ return false;
+ }
+ last_off = st_off + st->as_Store()->memory_size();
+ }
+ return true;
+}
+#endif //ASSERT
+
+
+
+
+//============================MergeMemNode=====================================
+//
+// SEMANTICS OF MEMORY MERGES: A MergeMem is a memory state assembled from several
+// contributing store or call operations. Each contributor provides the memory
+// state for a particular "alias type" (see Compile::alias_type). For example,
+// if a MergeMem has an input X for alias category #6, then any memory reference
+// to alias category #6 may use X as its memory state input, as an exact equivalent
+// to using the MergeMem as a whole.
+// Load<6>( MergeMem(<6>: X, ...), p ) <==> Load<6>(X,p)
+//
+// (Here, the <N> notation gives the index of the relevant adr_type.)
+//
+// In one special case (and more cases in the future), alias categories overlap.
+// The special alias category "Bot" (Compile::AliasIdxBot) includes all memory
+// states. Therefore, if a MergeMem has only one contributing input W for Bot,
+// it is exactly equivalent to that state W:
+// MergeMem(<Bot>: W) <==> W
+//
+// Usually, the merge has more than one input. In that case, where inputs
+// overlap (i.e., one is Bot), the narrower alias type determines the memory
+// state for that type, and the wider alias type (Bot) fills in everywhere else:
+// Load<5>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<5>(W,p)
+// Load<6>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<6>(X,p)
+//
+// A merge can take a "wide" memory state as one of its narrow inputs.
+// This simply means that the merge observes out only the relevant parts of
+// the wide input. That is, wide memory states arriving at narrow merge inputs
+// are implicitly "filtered" or "sliced" as necessary. (This is rare.)
+//
+// These rules imply that MergeMem nodes may cascade (via their <Bot> links),
+// and that memory slices "leak through":
+// MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y)) <==> MergeMem(<Bot>: W, <7>: Y)
+//
+// But, in such a cascade, repeated memory slices can "block the leak":
+// MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y), <7>: Y') <==> MergeMem(<Bot>: W, <7>: Y')
+//
+// In the last example, Y is not part of the combined memory state of the
+// outermost MergeMem. The system must, of course, prevent unschedulable
+// memory states from arising, so you can be sure that the state Y is somehow
+// a precursor to state Y'.
+//
+//
+// REPRESENTATION OF MEMORY MERGES: The indexes used to address the Node::in array
+// of each MergeMemNode array are exactly the numerical alias indexes, including
+// but not limited to AliasIdxTop, AliasIdxBot, and AliasIdxRaw. The functions
+// Compile::alias_type (and kin) produce and manage these indexes.
+//
+// By convention, the value of in(AliasIdxTop) (i.e., in(1)) is always the top node.
+// (Note that this provides quick access to the top node inside MergeMem methods,
+// without the need to reach out via TLS to Compile::current.)
+//
+// As a consequence of what was just described, a MergeMem that represents a full
+// memory state has an edge in(AliasIdxBot) which is a "wide" memory state,
+// containing all alias categories.
+//
+// MergeMem nodes never (?) have control inputs, so in(0) is NULL.
+//
+// All other edges in(N) (including in(AliasIdxRaw), which is in(3)) are either
+// a memory state for the alias type <N>, or else the top node, meaning that
+// there is no particular input for that alias type. Note that the length of
+// a MergeMem is variable, and may be extended at any time to accommodate new
+// memory states at larger alias indexes. When merges grow, they are of course
+// filled with "top" in the unused in() positions.
+//
+// This use of top is named "empty_memory()", or "empty_mem" (no-memory) as a variable.
+// (Top was chosen because it works smoothly with passes like GCM.)
+//
+// For convenience, we hardwire the alias index for TypeRawPtr::BOTTOM. (It is
+// the type of random VM bits like TLS references.) Since it is always the
+// first non-Bot memory slice, some low-level loops use it to initialize an
+// index variable: for (i = AliasIdxRaw; i < req(); i++).
+//
+//
+// ACCESSORS: There is a special accessor MergeMemNode::base_memory which returns
+// the distinguished "wide" state. The accessor MergeMemNode::memory_at(N) returns
+// the memory state for alias type <N>, or (if there is no particular slice at <N>,
+// it returns the base memory. To prevent bugs, memory_at does not accept <Top>
+// or <Bot> indexes. The iterator MergeMemStream provides robust iteration over
+// MergeMem nodes or pairs of such nodes, ensuring that the non-top edges are visited.
+//
+// %%%% We may get rid of base_memory as a separate accessor at some point; it isn't
+// really that different from the other memory inputs. An abbreviation called
+// "bot_memory()" for "memory_at(AliasIdxBot)" would keep code tidy.
+//
+//
+// PARTIAL MEMORY STATES: During optimization, MergeMem nodes may arise that represent
+// partial memory states. When a Phi splits through a MergeMem, the copy of the Phi
+// that "emerges though" the base memory will be marked as excluding the alias types
+// of the other (narrow-memory) copies which "emerged through" the narrow edges:
+//
+// Phi<Bot>(U, MergeMem(<Bot>: W, <8>: Y))
+// ==Ideal=> MergeMem(<Bot>: Phi<Bot-8>(U, W), Phi<8>(U, Y))
+//
+// This strange "subtraction" effect is necessary to ensure IGVN convergence.
+// (It is currently unimplemented.) As you can see, the resulting merge is
+// actually a disjoint union of memory states, rather than an overlay.
+//
+
+//------------------------------MergeMemNode-----------------------------------
+Node* MergeMemNode::make_empty_memory() {
+ Node* empty_memory = (Node*) Compile::current()->top();
+ assert(empty_memory->is_top(), "correct sentinel identity");
+ return empty_memory;
+}
+
+MergeMemNode::MergeMemNode(Node *new_base) : Node(1+Compile::AliasIdxRaw) {
+ init_class_id(Class_MergeMem);
+ // all inputs are nullified in Node::Node(int)
+ // set_input(0, NULL); // no control input
+
+ // Initialize the edges uniformly to top, for starters.
+ Node* empty_mem = make_empty_memory();
+ for (uint i = Compile::AliasIdxTop; i < req(); i++) {
+ init_req(i,empty_mem);
+ }
+ assert(empty_memory() == empty_mem, "");
+
+ if( new_base != NULL && new_base->is_MergeMem() ) {
+ MergeMemNode* mdef = new_base->as_MergeMem();
+ assert(mdef->empty_memory() == empty_mem, "consistent sentinels");
+ for (MergeMemStream mms(this, mdef); mms.next_non_empty2(); ) {
+ mms.set_memory(mms.memory2());
+ }
+ assert(base_memory() == mdef->base_memory(), "");
+ } else {
+ set_base_memory(new_base);
+ }
+}
+
+// Make a new, untransformed MergeMem with the same base as 'mem'.
+// If mem is itself a MergeMem, populate the result with the same edges.
+MergeMemNode* MergeMemNode::make(Compile* C, Node* mem) {
+ return new(C, 1+Compile::AliasIdxRaw) MergeMemNode(mem);
+}
+
+//------------------------------cmp--------------------------------------------
+uint MergeMemNode::hash() const { return NO_HASH; }
+uint MergeMemNode::cmp( const Node &n ) const {
+ return (&n == this); // Always fail except on self
+}
+
+//------------------------------Identity---------------------------------------
+Node* MergeMemNode::Identity(PhaseTransform *phase) {
+ // Identity if this merge point does not record any interesting memory
+ // disambiguations.
+ Node* base_mem = base_memory();
+ Node* empty_mem = empty_memory();
+ if (base_mem != empty_mem) { // Memory path is not dead?
+ for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+ Node* mem = in(i);
+ if (mem != empty_mem && mem != base_mem) {
+ return this; // Many memory splits; no change
+ }
+ }
+ }
+ return base_mem; // No memory splits; ID on the one true input
+}
+
+//------------------------------Ideal------------------------------------------
+// This method is invoked recursively on chains of MergeMem nodes
+Node *MergeMemNode::Ideal(PhaseGVN *phase, bool can_reshape) {
+ // Remove chain'd MergeMems
+ //
+ // This is delicate, because the each "in(i)" (i >= Raw) is interpreted
+ // relative to the "in(Bot)". Since we are patching both at the same time,
+ // we have to be careful to read each "in(i)" relative to the old "in(Bot)",
+ // but rewrite each "in(i)" relative to the new "in(Bot)".
+ Node *progress = NULL;
+
+
+ Node* old_base = base_memory();
+ Node* empty_mem = empty_memory();
+ if (old_base == empty_mem)
+ return NULL; // Dead memory path.
+
+ MergeMemNode* old_mbase;
+ if (old_base != NULL && old_base->is_MergeMem())
+ old_mbase = old_base->as_MergeMem();
+ else
+ old_mbase = NULL;
+ Node* new_base = old_base;
+
+ // simplify stacked MergeMems in base memory
+ if (old_mbase) new_base = old_mbase->base_memory();
+
+ // the base memory might contribute new slices beyond my req()
+ if (old_mbase) grow_to_match(old_mbase);
+
+ // Look carefully at the base node if it is a phi.
+ PhiNode* phi_base;
+ if (new_base != NULL && new_base->is_Phi())
+ phi_base = new_base->as_Phi();
+ else
+ phi_base = NULL;
+
+ Node* phi_reg = NULL;
+ uint phi_len = (uint)-1;
+ if (phi_base != NULL && !phi_base->is_copy()) {
+ // do not examine phi if degraded to a copy
+ phi_reg = phi_base->region();
+ phi_len = phi_base->req();
+ // see if the phi is unfinished
+ for (uint i = 1; i < phi_len; i++) {
+ if (phi_base->in(i) == NULL) {
+ // incomplete phi; do not look at it yet!
+ phi_reg = NULL;
+ phi_len = (uint)-1;
+ break;
+ }
+ }
+ }
+
+ // Note: We do not call verify_sparse on entry, because inputs
+ // can normalize to the base_memory via subsume_node or similar
+ // mechanisms. This method repairs that damage.
+
+ assert(!old_mbase || old_mbase->is_empty_memory(empty_mem), "consistent sentinels");
+
+ // Look at each slice.
+ for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+ Node* old_in = in(i);
+ // calculate the old memory value
+ Node* old_mem = old_in;
+ if (old_mem == empty_mem) old_mem = old_base;
+ assert(old_mem == memory_at(i), "");
+
+ // maybe update (reslice) the old memory value
+
+ // simplify stacked MergeMems
+ Node* new_mem = old_mem;
+ MergeMemNode* old_mmem;
+ if (old_mem != NULL && old_mem->is_MergeMem())
+ old_mmem = old_mem->as_MergeMem();
+ else
+ old_mmem = NULL;
+ if (old_mmem == this) {
+ // This can happen if loops break up and safepoints disappear.
+ // A merge of BotPtr (default) with a RawPtr memory derived from a
+ // safepoint can be rewritten to a merge of the same BotPtr with
+ // the BotPtr phi coming into the loop. If that phi disappears
+ // also, we can end up with a self-loop of the mergemem.
+ // In general, if loops degenerate and memory effects disappear,
+ // a mergemem can be left looking at itself. This simply means
+ // that the mergemem's default should be used, since there is
+ // no longer any apparent effect on this slice.
+ // Note: If a memory slice is a MergeMem cycle, it is unreachable
+ // from start. Update the input to TOP.
+ new_mem = (new_base == this || new_base == empty_mem)? empty_mem : new_base;
+ }
+ else if (old_mmem != NULL) {
+ new_mem = old_mmem->memory_at(i);
+ }
+ // else preceeding memory was not a MergeMem
+
+ // replace equivalent phis (unfortunately, they do not GVN together)
+ if (new_mem != NULL && new_mem != new_base &&
+ new_mem->req() == phi_len && new_mem->in(0) == phi_reg) {
+ if (new_mem->is_Phi()) {
+ PhiNode* phi_mem = new_mem->as_Phi();
+ for (uint i = 1; i < phi_len; i++) {
+ if (phi_base->in(i) != phi_mem->in(i)) {
+ phi_mem = NULL;
+ break;
+ }
+ }
+ if (phi_mem != NULL) {
+ // equivalent phi nodes; revert to the def
+ new_mem = new_base;
+ }
+ }
+ }
+
+ // maybe store down a new value
+ Node* new_in = new_mem;
+ if (new_in == new_base) new_in = empty_mem;
+
+ if (new_in != old_in) {
+ // Warning: Do not combine this "if" with the previous "if"
+ // A memory slice might have be be rewritten even if it is semantically
+ // unchanged, if the base_memory value has changed.
+ set_req(i, new_in);
+ progress = this; // Report progress
+ }
+ }
+
+ if (new_base != old_base) {
+ set_req(Compile::AliasIdxBot, new_base);
+ // Don't use set_base_memory(new_base), because we need to update du.
+ assert(base_memory() == new_base, "");
+ progress = this;
+ }
+
+ if( base_memory() == this ) {
+ // a self cycle indicates this memory path is dead
+ set_req(Compile::AliasIdxBot, empty_mem);
+ }
+
+ // Resolve external cycles by calling Ideal on a MergeMem base_memory
+ // Recursion must occur after the self cycle check above
+ if( base_memory()->is_MergeMem() ) {
+ MergeMemNode *new_mbase = base_memory()->as_MergeMem();
+ Node *m = phase->transform(new_mbase); // Rollup any cycles
+ if( m != NULL && (m->is_top() ||
+ m->is_MergeMem() && m->as_MergeMem()->base_memory() == empty_mem) ) {
+ // propagate rollup of dead cycle to self
+ set_req(Compile::AliasIdxBot, empty_mem);
+ }
+ }
+
+ if( base_memory() == empty_mem ) {
+ progress = this;
+ // Cut inputs during Parse phase only.
+ // During Optimize phase a dead MergeMem node will be subsumed by Top.
+ if( !can_reshape ) {
+ for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+ if( in(i) != empty_mem ) { set_req(i, empty_mem); }
+ }
+ }
+ }
+
+ if( !progress && base_memory()->is_Phi() && can_reshape ) {
+ // Check if PhiNode::Ideal's "Split phis through memory merges"
+ // transform should be attempted. Look for this->phi->this cycle.
+ uint merge_width = req();
+ if (merge_width > Compile::AliasIdxRaw) {
+ PhiNode* phi = base_memory()->as_Phi();
+ for( uint i = 1; i < phi->req(); ++i ) {// For all paths in
+ if (phi->in(i) == this) {
+ phase->is_IterGVN()->_worklist.push(phi);
+ break;
+ }
+ }
+ }
+ }
+
+ assert(verify_sparse(), "please, no dups of base");
+ return progress;
+}
+
+//-------------------------set_base_memory-------------------------------------
+void MergeMemNode::set_base_memory(Node *new_base) {
+ Node* empty_mem = empty_memory();
+ set_req(Compile::AliasIdxBot, new_base);
+ assert(memory_at(req()) == new_base, "must set default memory");
+ // Clear out other occurrences of new_base:
+ if (new_base != empty_mem) {
+ for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+ if (in(i) == new_base) set_req(i, empty_mem);
+ }
+ }
+}
+
+//------------------------------out_RegMask------------------------------------
+const RegMask &MergeMemNode::out_RegMask() const {
+ return RegMask::Empty;
+}
+
+//------------------------------dump_spec--------------------------------------
+#ifndef PRODUCT
+void MergeMemNode::dump_spec(outputStream *st) const {
+ st->print(" {");
+ Node* base_mem = base_memory();
+ for( uint i = Compile::AliasIdxRaw; i < req(); i++ ) {
+ Node* mem = memory_at(i);
+ if (mem == base_mem) { st->print(" -"); continue; }
+ st->print( " N%d:", mem->_idx );
+ Compile::current()->get_adr_type(i)->dump_on(st);
+ }
+ st->print(" }");
+}
+#endif // !PRODUCT
+
+
+#ifdef ASSERT
+static bool might_be_same(Node* a, Node* b) {
+ if (a == b) return true;
+ if (!(a->is_Phi() || b->is_Phi())) return false;
+ // phis shift around during optimization
+ return true; // pretty stupid...
+}
+
+// verify a narrow slice (either incoming or outgoing)
+static void verify_memory_slice(const MergeMemNode* m, int alias_idx, Node* n) {
+ if (!VerifyAliases) return; // don't bother to verify unless requested
+ if (is_error_reported()) return; // muzzle asserts when debugging an error
+ if (Node::in_dump()) return; // muzzle asserts when printing
+ assert(alias_idx >= Compile::AliasIdxRaw, "must not disturb base_memory or sentinel");
+ assert(n != NULL, "");
+ // Elide intervening MergeMem's
+ while (n->is_MergeMem()) {
+ n = n->as_MergeMem()->memory_at(alias_idx);
+ }
+ Compile* C = Compile::current();
+ const TypePtr* n_adr_type = n->adr_type();
+ if (n == m->empty_memory()) {
+ // Implicit copy of base_memory()
+ } else if (n_adr_type != TypePtr::BOTTOM) {
+ assert(n_adr_type != NULL, "new memory must have a well-defined adr_type");
+ assert(C->must_alias(n_adr_type, alias_idx), "new memory must match selected slice");
+ } else {
+ // A few places like make_runtime_call "know" that VM calls are narrow,
+ // and can be used to update only the VM bits stored as TypeRawPtr::BOTTOM.
+ bool expected_wide_mem = false;
+ if (n == m->base_memory()) {
+ expected_wide_mem = true;
+ } else if (alias_idx == Compile::AliasIdxRaw ||
+ n == m->memory_at(Compile::AliasIdxRaw)) {
+ expected_wide_mem = true;
+ } else if (!C->alias_type(alias_idx)->is_rewritable()) {
+ // memory can "leak through" calls on channels that
+ // are write-once. Allow this also.
+ expected_wide_mem = true;
+ }
+ assert(expected_wide_mem, "expected narrow slice replacement");
+ }
+}
+#else // !ASSERT
+#define verify_memory_slice(m,i,n) (0) // PRODUCT version is no-op
+#endif
+
+
+//-----------------------------memory_at---------------------------------------
+Node* MergeMemNode::memory_at(uint alias_idx) const {
+ assert(alias_idx >= Compile::AliasIdxRaw ||
+ alias_idx == Compile::AliasIdxBot && Compile::current()->AliasLevel() == 0,
+ "must avoid base_memory and AliasIdxTop");
+
+ // Otherwise, it is a narrow slice.
+ Node* n = alias_idx < req() ? in(alias_idx) : empty_memory();
+ Compile *C = Compile::current();
+ if (is_empty_memory(n)) {
+ // the array is sparse; empty slots are the "top" node
+ n = base_memory();
+ assert(Node::in_dump()
+ || n == NULL || n->bottom_type() == Type::TOP
+ || n->adr_type() == TypePtr::BOTTOM
+ || n->adr_type() == TypeRawPtr::BOTTOM
+ || Compile::current()->AliasLevel() == 0,
+ "must be a wide memory");
+ // AliasLevel == 0 if we are organizing the memory states manually.
+ // See verify_memory_slice for comments on TypeRawPtr::BOTTOM.
+ } else {
+ // make sure the stored slice is sane
+ #ifdef ASSERT
+ if (is_error_reported() || Node::in_dump()) {
+ } else if (might_be_same(n, base_memory())) {
+ // Give it a pass: It is a mostly harmless repetition of the base.
+ // This can arise normally from node subsumption during optimization.
+ } else {
+ verify_memory_slice(this, alias_idx, n);
+ }
+ #endif
+ }
+ return n;
+}
+
+//---------------------------set_memory_at-------------------------------------
+void MergeMemNode::set_memory_at(uint alias_idx, Node *n) {
+ verify_memory_slice(this, alias_idx, n);
+ Node* empty_mem = empty_memory();
+ if (n == base_memory()) n = empty_mem; // collapse default
+ uint need_req = alias_idx+1;
+ if (req() < need_req) {
+ if (n == empty_mem) return; // already the default, so do not grow me
+ // grow the sparse array
+ do {
+ add_req(empty_mem);
+ } while (req() < need_req);
+ }
+ set_req( alias_idx, n );
+}
+
+
+
+//--------------------------iteration_setup------------------------------------
+void MergeMemNode::iteration_setup(const MergeMemNode* other) {
+ if (other != NULL) {
+ grow_to_match(other);
+ // invariant: the finite support of mm2 is within mm->req()
+ #ifdef ASSERT
+ for (uint i = req(); i < other->req(); i++) {
+ assert(other->is_empty_memory(other->in(i)), "slice left uncovered");
+ }
+ #endif
+ }
+ // Replace spurious copies of base_memory by top.
+ Node* base_mem = base_memory();
+ if (base_mem != NULL && !base_mem->is_top()) {
+ for (uint i = Compile::AliasIdxBot+1, imax = req(); i < imax; i++) {
+ if (in(i) == base_mem)
+ set_req(i, empty_memory());
+ }
+ }
+}
+
+//---------------------------grow_to_match-------------------------------------
+void MergeMemNode::grow_to_match(const MergeMemNode* other) {
+ Node* empty_mem = empty_memory();
+ assert(other->is_empty_memory(empty_mem), "consistent sentinels");
+ // look for the finite support of the other memory
+ for (uint i = other->req(); --i >= req(); ) {
+ if (other->in(i) != empty_mem) {
+ uint new_len = i+1;
+ while (req() < new_len) add_req(empty_mem);
+ break;
+ }
+ }
+}
+
+//---------------------------verify_sparse-------------------------------------
+#ifndef PRODUCT
+bool MergeMemNode::verify_sparse() const {
+ assert(is_empty_memory(make_empty_memory()), "sane sentinel");
+ Node* base_mem = base_memory();
+ // The following can happen in degenerate cases, since empty==top.
+ if (is_empty_memory(base_mem)) return true;
+ for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
+ assert(in(i) != NULL, "sane slice");
+ if (in(i) == base_mem) return false; // should have been the sentinel value!
+ }
+ return true;
+}
+
+bool MergeMemStream::match_memory(Node* mem, const MergeMemNode* mm, int idx) {
+ Node* n;
+ n = mm->in(idx);
+ if (mem == n) return true; // might be empty_memory()
+ n = (idx == Compile::AliasIdxBot)? mm->base_memory(): mm->memory_at(idx);
+ if (mem == n) return true;
+ while (n->is_Phi() && (n = n->as_Phi()->is_copy()) != NULL) {
+ if (mem == n) return true;
+ if (n == NULL) break;
+ }
+ return false;
+}
+#endif // !PRODUCT