| /* |
| * 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; |
| |
| // The code which unhooks non-raw memories from complete (macro-expanded) |
| // initializations was removed. After macro-expansion all stores catched |
| // by Initialize node became raw stores and there is no information |
| // which memory slices they modify. So it is unsafe to move any memory |
| // operation above these stores. Also in most cases hooked non-raw memories |
| // were already unhooked by using information from detect_ptr_independence() |
| // and find_previous_store(). |
| |
| 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); |
| |
| const TypeInstPtr* tp = phase->type(ld_adr)->isa_instptr(); |
| Compile::AliasType* atp = tp != NULL ? phase->C->alias_type(tp) : NULL; |
| if (EliminateAutoBox && atp != NULL && atp->index() >= Compile::AliasIdxRaw && |
| atp->field() != NULL && !atp->field()->is_volatile()) { |
| uint alias_idx = atp->index(); |
| bool final = atp->field()->is_final(); |
| Node* result = NULL; |
| Node* current = st; |
| // Skip through chains of MemBarNodes checking the MergeMems for |
| // new states for the slice of this load. Stop once any other |
| // kind of node is encountered. Loads from final memory can skip |
| // through any kind of MemBar but normal loads shouldn't skip |
| // through MemBarAcquire since the could allow them to move out of |
| // a synchronized region. |
| while (current->is_Proj()) { |
| int opc = current->in(0)->Opcode(); |
| if ((final && opc == Op_MemBarAcquire) || |
| opc == Op_MemBarRelease || opc == Op_MemBarCPUOrder) { |
| Node* mem = current->in(0)->in(TypeFunc::Memory); |
| if (mem->is_MergeMem()) { |
| MergeMemNode* merge = mem->as_MergeMem(); |
| Node* new_st = merge->memory_at(alias_idx); |
| if (new_st == merge->base_memory()) { |
| // Keep searching |
| current = merge->base_memory(); |
| continue; |
| } |
| // Save the new memory state for the slice and fall through |
| // to exit. |
| result = new_st; |
| } |
| } |
| break; |
| } |
| if (result != NULL) { |
| st = result; |
| } |
| } |
| |
| |
| // 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; |
| } |
| |
| |
| // Returns true if the AliasType refers to the field that holds the |
| // cached box array. Currently only handles the IntegerCache case. |
| static bool is_autobox_cache(Compile::AliasType* atp) { |
| if (atp != NULL && atp->field() != NULL) { |
| ciField* field = atp->field(); |
| ciSymbol* klass = field->holder()->name(); |
| if (field->name() == ciSymbol::cache_field_name() && |
| field->holder()->uses_default_loader() && |
| klass == ciSymbol::java_lang_Integer_IntegerCache()) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Fetch the base value in the autobox array |
| static bool fetch_autobox_base(Compile::AliasType* atp, int& cache_offset) { |
| if (atp != NULL && atp->field() != NULL) { |
| ciField* field = atp->field(); |
| ciSymbol* klass = field->holder()->name(); |
| if (field->name() == ciSymbol::cache_field_name() && |
| field->holder()->uses_default_loader() && |
| klass == ciSymbol::java_lang_Integer_IntegerCache()) { |
| assert(field->is_constant(), "what?"); |
| ciObjArray* array = field->constant_value().as_object()->as_obj_array(); |
| // Fetch the box object at the base of the array and get its value |
| ciInstance* box = array->obj_at(0)->as_instance(); |
| ciInstanceKlass* ik = box->klass()->as_instance_klass(); |
| if (ik->nof_nonstatic_fields() == 1) { |
| // This should be true nonstatic_field_at requires calling |
| // nof_nonstatic_fields so check it anyway |
| ciConstant c = box->field_value(ik->nonstatic_field_at(0)); |
| cache_offset = c.as_int(); |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Returns true if the AliasType refers to the value field of an |
| // autobox object. Currently only handles Integer. |
| static bool is_autobox_object(Compile::AliasType* atp) { |
| if (atp != NULL && atp->field() != NULL) { |
| ciField* field = atp->field(); |
| ciSymbol* klass = field->holder()->name(); |
| if (field->name() == ciSymbol::value_name() && |
| field->holder()->uses_default_loader() && |
| klass == ciSymbol::java_lang_Integer()) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| |
| // We're loading from an object which has autobox behaviour. |
| // If this object is result of a valueOf call we'll have a phi |
| // merging a newly allocated object and a load from the cache. |
| // We want to replace this load with the original incoming |
| // argument to the valueOf call. |
| Node* LoadNode::eliminate_autobox(PhaseGVN* phase) { |
| Node* base = in(Address)->in(AddPNode::Base); |
| if (base->is_Phi() && base->req() == 3) { |
| AllocateNode* allocation = NULL; |
| int allocation_index = -1; |
| int load_index = -1; |
| for (uint i = 1; i < base->req(); i++) { |
| allocation = AllocateNode::Ideal_allocation(base->in(i), phase); |
| if (allocation != NULL) { |
| allocation_index = i; |
| load_index = 3 - allocation_index; |
| break; |
| } |
| } |
| LoadNode* load = NULL; |
| if (allocation != NULL && base->in(load_index)->is_Load()) { |
| load = base->in(load_index)->as_Load(); |
| } |
| if (load != NULL && in(Memory)->is_Phi() && in(Memory)->in(0) == base->in(0)) { |
| // Push the loads from the phi that comes from valueOf up |
| // through it to allow elimination of the loads and the recovery |
| // of the original value. |
| Node* mem_phi = in(Memory); |
| Node* offset = in(Address)->in(AddPNode::Offset); |
| |
| Node* in1 = clone(); |
| Node* in1_addr = in1->in(Address)->clone(); |
| in1_addr->set_req(AddPNode::Base, base->in(allocation_index)); |
| in1_addr->set_req(AddPNode::Address, base->in(allocation_index)); |
| in1_addr->set_req(AddPNode::Offset, offset); |
| in1->set_req(0, base->in(allocation_index)); |
| in1->set_req(Address, in1_addr); |
| in1->set_req(Memory, mem_phi->in(allocation_index)); |
| |
| Node* in2 = clone(); |
| Node* in2_addr = in2->in(Address)->clone(); |
| in2_addr->set_req(AddPNode::Base, base->in(load_index)); |
| in2_addr->set_req(AddPNode::Address, base->in(load_index)); |
| in2_addr->set_req(AddPNode::Offset, offset); |
| in2->set_req(0, base->in(load_index)); |
| in2->set_req(Address, in2_addr); |
| in2->set_req(Memory, mem_phi->in(load_index)); |
| |
| in1_addr = phase->transform(in1_addr); |
| in1 = phase->transform(in1); |
| in2_addr = phase->transform(in2_addr); |
| in2 = phase->transform(in2); |
| |
| PhiNode* result = PhiNode::make_blank(base->in(0), this); |
| result->set_req(allocation_index, in1); |
| result->set_req(load_index, in2); |
| return result; |
| } |
| } else if (base->is_Load()) { |
| // Eliminate the load of Integer.value for integers from the cache |
| // array by deriving the value from the index into the array. |
| // Capture the offset of the load and then reverse the computation. |
| Node* load_base = base->in(Address)->in(AddPNode::Base); |
| if (load_base != NULL) { |
| Compile::AliasType* atp = phase->C->alias_type(load_base->adr_type()); |
| intptr_t cache_offset; |
| int shift = -1; |
| Node* cache = NULL; |
| if (is_autobox_cache(atp)) { |
| shift = exact_log2(type2aelembytes(T_OBJECT)); |
| cache = AddPNode::Ideal_base_and_offset(load_base->in(Address), phase, cache_offset); |
| } |
| if (cache != NULL && base->in(Address)->is_AddP()) { |
| Node* elements[4]; |
| int count = base->in(Address)->as_AddP()->unpack_offsets(elements, ARRAY_SIZE(elements)); |
| int cache_low; |
| if (count > 0 && fetch_autobox_base(atp, cache_low)) { |
| int offset = arrayOopDesc::base_offset_in_bytes(memory_type()) - (cache_low << shift); |
| // Add up all the offsets making of the address of the load |
| Node* result = elements[0]; |
| for (int i = 1; i < count; i++) { |
| result = phase->transform(new (phase->C, 3) AddXNode(result, elements[i])); |
| } |
| // Remove the constant offset from the address and then |
| // remove the scaling of the offset to recover the original index. |
| result = phase->transform(new (phase->C, 3) AddXNode(result, phase->MakeConX(-offset))); |
| if (result->Opcode() == Op_LShiftX && result->in(2) == phase->intcon(shift)) { |
| // Peel the shift off directly but wrap it in a dummy node |
| // since Ideal can't return existing nodes |
| result = new (phase->C, 3) RShiftXNode(result->in(1), phase->intcon(0)); |
| } else { |
| result = new (phase->C, 3) RShiftXNode(result, phase->intcon(shift)); |
| } |
| #ifdef _LP64 |
| result = new (phase->C, 2) ConvL2INode(phase->transform(result)); |
| #endif |
| return result; |
| } |
| } |
| } |
| } |
| return NULL; |
| } |
| |
| |
| //------------------------------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); |
| } |
| } |
| |
| if (EliminateAutoBox && can_reshape && in(Address)->is_AddP()) { |
| Node* base = in(Address)->in(AddPNode::Base); |
| if (base != NULL) { |
| Compile::AliasType* atp = phase->C->alias_type(adr_type()); |
| if (is_autobox_object(atp)) { |
| Node* result = eliminate_autobox(phase); |
| if (result != NULL) return result; |
| } |
| } |
| } |
| |
| // 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; |
| } |
| |
| if (EliminateAutoBox) { |
| // The pointers in the autobox arrays are always non-null |
| Node* base = in(Address)->in(AddPNode::Base); |
| if (base != NULL) { |
| Compile::AliasType* atp = phase->C->alias_type(base->adr_type()); |
| if (is_autobox_cache(atp)) { |
| return jt->join(TypePtr::NOTNULL)->is_ptr(); |
| } |
| } |
| } |
| 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 { |
| // Either input is TOP ==> the result is TOP |
| const Type *t = phase->type( in(MemNode::Memory) ); |
| if( t == Type::TOP ) return Type::TOP; |
| t = phase->type( in(MemNode::Address) ); |
| if( t == Type::TOP ) return Type::TOP; |
| t = phase->type( in(MemNode::ValueIn) ); |
| if( t == Type::TOP ) return Type::TOP; |
| // If extra input is TOP ==> the result is TOP |
| t = phase->type( in(MemNode::OopStore) ); |
| if( t == 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 |