|
/*
* Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "compiler/compileLog.hpp"
#include "gc/shared/collectedHeap.inline.hpp"
#include "gc/shared/tlab_globals.hpp"
#include "libadt/vectset.hpp"
#include "memory/universe.hpp"
#include "opto/addnode.hpp"
#include "opto/arraycopynode.hpp"
#include "opto/callnode.hpp"
#include "opto/castnode.hpp"
#include "opto/cfgnode.hpp"
#include "opto/compile.hpp"
#include "opto/convertnode.hpp"
#include "opto/graphKit.hpp"
#include "opto/intrinsicnode.hpp"
#include "opto/locknode.hpp"
#include "opto/loopnode.hpp"
#include "opto/macro.hpp"
#include "opto/memnode.hpp"
#include "opto/narrowptrnode.hpp"
#include "opto/node.hpp"
#include "opto/opaquenode.hpp"
#include "opto/phaseX.hpp"
#include "opto/rootnode.hpp"
#include "opto/runtime.hpp"
#include "opto/subnode.hpp"
#include "opto/subtypenode.hpp"
#include "opto/type.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/continuation.hpp"
#include "runtime/sharedRuntime.hpp"
#include "utilities/macros.hpp"
#include "utilities/powerOfTwo.hpp"
#if INCLUDE_G1GC
#include "gc/g1/g1ThreadLocalData.hpp"
#endif // INCLUDE_G1GC
//
// Replace any references to "oldref" in inputs to "use" with "newref".
// Returns the number of replacements made.
//
int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
int nreplacements = 0;
uint req = use->req();
for (uint j = 0; j < use->len(); j++) {
Node *uin = use->in(j);
if (uin == oldref) {
if (j < req)
use->set_req(j, newref);
else
use->set_prec(j, newref);
nreplacements++;
} else if (j >= req && uin == NULL) {
break;
}
}
return nreplacements;
}
void PhaseMacroExpand::migrate_outs(Node *old, Node *target) {
assert(old != NULL, "sanity");
for (DUIterator_Fast imax, i = old->fast_outs(imax); i < imax; i++) {
Node* use = old->fast_out(i);
_igvn.rehash_node_delayed(use);
imax -= replace_input(use, old, target);
// back up iterator
--i;
}
assert(old->outcnt() == 0, "all uses must be deleted");
}
Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word, int mask, int bits, bool return_fast_path) {
Node* cmp;
if (mask != 0) {
Node* and_node = transform_later(new AndXNode(word, MakeConX(mask)));
cmp = transform_later(new CmpXNode(and_node, MakeConX(bits)));
} else {
cmp = word;
}
Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
transform_later(iff);
// Fast path taken.
Node *fast_taken = transform_later(new IfFalseNode(iff));
// Fast path not-taken, i.e. slow path
Node *slow_taken = transform_later(new IfTrueNode(iff));
if (return_fast_path) {
region->init_req(edge, slow_taken); // Capture slow-control
return fast_taken;
} else {
region->init_req(edge, fast_taken); // Capture fast-control
return slow_taken;
}
}
//--------------------copy_predefined_input_for_runtime_call--------------------
void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
// Set fixed predefined input arguments
call->init_req( TypeFunc::Control, ctrl );
call->init_req( TypeFunc::I_O , oldcall->in( TypeFunc::I_O) );
call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
}
//------------------------------make_slow_call---------------------------------
CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
address slow_call, const char* leaf_name, Node* slow_path,
Node* parm0, Node* parm1, Node* parm2) {
// Slow-path call
CallNode *call = leaf_name
? (CallNode*)new CallLeafNode ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
: (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
// Slow path call has no side-effects, uses few values
copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
if (parm0 != NULL) call->init_req(TypeFunc::Parms+0, parm0);
if (parm1 != NULL) call->init_req(TypeFunc::Parms+1, parm1);
if (parm2 != NULL) call->init_req(TypeFunc::Parms+2, parm2);
call->copy_call_debug_info(&_igvn, oldcall);
call->set_cnt(PROB_UNLIKELY_MAG(4)); // Same effect as RC_UNCOMMON.
_igvn.replace_node(oldcall, call);
transform_later(call);
return call;
}
void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
bs->eliminate_gc_barrier(this, p2x);
#ifndef PRODUCT
if (PrintOptoStatistics) {
Atomic::inc(&PhaseMacroExpand::_GC_barriers_removed_counter);
}
#endif
}
// Search for a memory operation for the specified memory slice.
static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
Node *orig_mem = mem;
Node *alloc_mem = alloc->in(TypeFunc::Memory);
const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
while (true) {
if (mem == alloc_mem || mem == start_mem ) {
return mem; // hit one of our sentinels
} else if (mem->is_MergeMem()) {
mem = mem->as_MergeMem()->memory_at(alias_idx);
} else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
Node *in = mem->in(0);
// we can safely skip over safepoints, calls, locks and membars because we
// already know that the object is safe to eliminate.
if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
return in;
} else if (in->is_Call()) {
CallNode *call = in->as_Call();
if (call->may_modify(tinst, phase)) {
assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
return in;
}
}
mem = in->in(TypeFunc::Memory);
} else if (in->is_MemBar()) {
ArrayCopyNode* ac = NULL;
if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
if (ac != NULL) {
assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
return ac;
}
}
mem = in->in(TypeFunc::Memory);
} else {
#ifdef ASSERT
in->dump();
mem->dump();
assert(false, "unexpected projection");
#endif
}
} else if (mem->is_Store()) {
const TypePtr* atype = mem->as_Store()->adr_type();
int adr_idx = phase->C->get_alias_index(atype);
if (adr_idx == alias_idx) {
assert(atype->isa_oopptr(), "address type must be oopptr");
int adr_offset = atype->offset();
uint adr_iid = atype->is_oopptr()->instance_id();
// Array elements references have the same alias_idx
// but different offset and different instance_id.
if (adr_offset == offset && adr_iid == alloc->_idx) {
return mem;
}
} else {
assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
}
mem = mem->in(MemNode::Memory);
} else if (mem->is_ClearArray()) {
if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
// Can not bypass initialization of the instance
// we are looking.
debug_only(intptr_t offset;)
assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
InitializeNode* init = alloc->as_Allocate()->initialization();
// We are looking for stored value, return Initialize node
// or memory edge from Allocate node.
if (init != NULL) {
return init;
} else {
return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
}
}
// Otherwise skip it (the call updated 'mem' value).
} else if (mem->Opcode() == Op_SCMemProj) {
mem = mem->in(0);
Node* adr = NULL;
if (mem->is_LoadStore()) {
adr = mem->in(MemNode::Address);
} else {
assert(mem->Opcode() == Op_EncodeISOArray ||
mem->Opcode() == Op_StrCompressedCopy, "sanity");
adr = mem->in(3); // Destination array
}
const TypePtr* atype = adr->bottom_type()->is_ptr();
int adr_idx = phase->C->get_alias_index(atype);
if (adr_idx == alias_idx) {
DEBUG_ONLY(mem->dump();)
assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
return NULL;
}
mem = mem->in(MemNode::Memory);
} else if (mem->Opcode() == Op_StrInflatedCopy) {
Node* adr = mem->in(3); // Destination array
const TypePtr* atype = adr->bottom_type()->is_ptr();
int adr_idx = phase->C->get_alias_index(atype);
if (adr_idx == alias_idx) {
DEBUG_ONLY(mem->dump();)
assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
return NULL;
}
mem = mem->in(MemNode::Memory);
} else {
return mem;
}
assert(mem != orig_mem, "dead memory loop");
}
}
// Generate loads from source of the arraycopy for fields of
// destination needed at a deoptimization point
Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type *ftype, AllocateNode *alloc) {
BasicType bt = ft;
const Type *type = ftype;
if (ft == T_NARROWOOP) {
bt = T_OBJECT;
type = ftype->make_oopptr();
}
Node* res = NULL;
if (ac->is_clonebasic()) {
assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
Node* base = ac->in(ArrayCopyNode::Src);
Node* adr = _igvn.transform(new AddPNode(base, base, MakeConX(offset)));
const TypePtr* adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
} else {
if (ac->modifies(offset, offset, &_igvn, true)) {
assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
uint shift = exact_log2(type2aelembytes(bt));
Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
Node* adr = NULL;
const TypePtr* adr_type = NULL;
if (src_pos_t->is_con() && dest_pos_t->is_con()) {
intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
Node* base = ac->in(ArrayCopyNode::Src);
adr = _igvn.transform(new AddPNode(base, base, MakeConX(off)));
adr_type = _igvn.type(base)->is_ptr()->add_offset(off);
if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
// Don't emit a new load from src if src == dst but try to get the value from memory instead
return value_from_mem(ac->in(TypeFunc::Memory), ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
}
} else {
Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
#ifdef _LP64
diff = _igvn.transform(new ConvI2LNode(diff));
#endif
diff = _igvn.transform(new LShiftXNode(diff, intcon(shift)));
Node* off = _igvn.transform(new AddXNode(MakeConX(offset), diff));
Node* base = ac->in(ArrayCopyNode::Src);
adr = _igvn.transform(new AddPNode(base, base, off));
adr_type = _igvn.type(base)->is_ptr()->add_offset(Type::OffsetBot);
if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
// Non constant offset in the array: we can't statically
// determine the value
return NULL;
}
}
MergeMemNode* mergemen = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemen, adr, adr_type, type, bt);
}
}
if (res != NULL) {
if (ftype->isa_narrowoop()) {
// PhaseMacroExpand::scalar_replacement adds DecodeN nodes
res = _igvn.transform(new EncodePNode(res, ftype));
}
return res;
}
return NULL;
}
//
// Given a Memory Phi, compute a value Phi containing the values from stores
// on the input paths.
// Note: this function is recursive, its depth is limited by the "level" argument
// Returns the computed Phi, or NULL if it cannot compute it.
Node *PhaseMacroExpand::value_from_mem_phi(Node *mem, BasicType ft, const Type *phi_type, const TypeOopPtr *adr_t, AllocateNode *alloc, Node_Stack *value_phis, int level) {
assert(mem->is_Phi(), "sanity");
int alias_idx = C->get_alias_index(adr_t);
int offset = adr_t->offset();
int instance_id = adr_t->instance_id();
// Check if an appropriate value phi already exists.
Node* region = mem->in(0);
for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
Node* phi = region->fast_out(k);
if (phi->is_Phi() && phi != mem &&
phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
return phi;
}
}
// Check if an appropriate new value phi already exists.
Node* new_phi = value_phis->find(mem->_idx);
if (new_phi != NULL)
return new_phi;
if (level <= 0) {
return NULL; // Give up: phi tree too deep
}
Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
Node *alloc_mem = alloc->in(TypeFunc::Memory);
uint length = mem->req();
GrowableArray <Node *> values(length, length, NULL);
// create a new Phi for the value
PhiNode *phi = new PhiNode(mem->in(0), phi_type, NULL, mem->_idx, instance_id, alias_idx, offset);
transform_later(phi);
value_phis->push(phi, mem->_idx);
for (uint j = 1; j < length; j++) {
Node *in = mem->in(j);
if (in == NULL || in->is_top()) {
values.at_put(j, in);
} else {
Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
if (val == start_mem || val == alloc_mem) {
// hit a sentinel, return appropriate 0 value
values.at_put(j, _igvn.zerocon(ft));
continue;
}
if (val->is_Initialize()) {
val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
}
if (val == NULL) {
return NULL; // can't find a value on this path
}
if (val == mem) {
values.at_put(j, mem);
} else if (val->is_Store()) {
Node* n = val->in(MemNode::ValueIn);
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
n = bs->step_over_gc_barrier(n);
if (is_subword_type(ft)) {
n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
}
values.at_put(j, n);
} else if(val->is_Proj() && val->in(0) == alloc) {
values.at_put(j, _igvn.zerocon(ft));
} else if (val->is_Phi()) {
val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
if (val == NULL) {
return NULL;
}
values.at_put(j, val);
} else if (val->Opcode() == Op_SCMemProj) {
assert(val->in(0)->is_LoadStore() ||
val->in(0)->Opcode() == Op_EncodeISOArray ||
val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
return NULL;
} else if (val->is_ArrayCopy()) {
Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
if (res == NULL) {
return NULL;
}
values.at_put(j, res);
} else {
DEBUG_ONLY( val->dump(); )
assert(false, "unknown node on this path");
return NULL; // unknown node on this path
}
}
}
// Set Phi's inputs
for (uint j = 1; j < length; j++) {
if (values.at(j) == mem) {
phi->init_req(j, phi);
} else {
phi->init_req(j, values.at(j));
}
}
return phi;
}
// Search the last value stored into the object's field.
Node *PhaseMacroExpand::value_from_mem(Node *sfpt_mem, Node *sfpt_ctl, BasicType ft, const Type *ftype, const TypeOopPtr *adr_t, AllocateNode *alloc) {
assert(adr_t->is_known_instance_field(), "instance required");
int instance_id = adr_t->instance_id();
assert((uint)instance_id == alloc->_idx, "wrong allocation");
int alias_idx = C->get_alias_index(adr_t);
int offset = adr_t->offset();
Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
Node *alloc_ctrl = alloc->in(TypeFunc::Control);
Node *alloc_mem = alloc->in(TypeFunc::Memory);
VectorSet visited;
bool done = sfpt_mem == alloc_mem;
Node *mem = sfpt_mem;
while (!done) {
if (visited.test_set(mem->_idx)) {
return NULL; // found a loop, give up
}
mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
if (mem == start_mem || mem == alloc_mem) {
done = true; // hit a sentinel, return appropriate 0 value
} else if (mem->is_Initialize()) {
mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
if (mem == NULL) {
done = true; // Something go wrong.
} else if (mem->is_Store()) {
const TypePtr* atype = mem->as_Store()->adr_type();
assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
done = true;
}
} else if (mem->is_Store()) {
const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
assert(atype != NULL, "address type must be oopptr");
assert(C->get_alias_index(atype) == alias_idx &&
atype->is_known_instance_field() && atype->offset() == offset &&
atype->instance_id() == instance_id, "store is correct memory slice");
done = true;
} else if (mem->is_Phi()) {
// try to find a phi's unique input
Node *unique_input = NULL;
Node *top = C->top();
for (uint i = 1; i < mem->req(); i++) {
Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
if (n == NULL || n == top || n == mem) {
continue;
} else if (unique_input == NULL) {
unique_input = n;
} else if (unique_input != n) {
unique_input = top;
break;
}
}
if (unique_input != NULL && unique_input != top) {
mem = unique_input;
} else {
done = true;
}
} else if (mem->is_ArrayCopy()) {
done = true;
} else {
DEBUG_ONLY( mem->dump(); )
assert(false, "unexpected node");
}
}
if (mem != NULL) {
if (mem == start_mem || mem == alloc_mem) {
// hit a sentinel, return appropriate 0 value
return _igvn.zerocon(ft);
} else if (mem->is_Store()) {
Node* n = mem->in(MemNode::ValueIn);
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
n = bs->step_over_gc_barrier(n);
return n;
} else if (mem->is_Phi()) {
// attempt to produce a Phi reflecting the values on the input paths of the Phi
Node_Stack value_phis(8);
Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
if (phi != NULL) {
return phi;
} else {
// Kill all new Phis
while(value_phis.is_nonempty()) {
Node* n = value_phis.node();
_igvn.replace_node(n, C->top());
value_phis.pop();
}
}
} else if (mem->is_ArrayCopy()) {
Node* ctl = mem->in(0);
Node* m = mem->in(TypeFunc::Memory);
if (sfpt_ctl->is_Proj() && sfpt_ctl->as_Proj()->is_uncommon_trap_proj(Deoptimization::Reason_none)) {
// pin the loads in the uncommon trap path
ctl = sfpt_ctl;
m = sfpt_mem;
}
return make_arraycopy_load(mem->as_ArrayCopy(), offset, ctl, m, ft, ftype, alloc);
}
}
// Something go wrong.
return NULL;
}
// Check the possibility of scalar replacement.
bool PhaseMacroExpand::can_eliminate_allocation(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
// Scan the uses of the allocation to check for anything that would
// prevent us from eliminating it.
NOT_PRODUCT( const char* fail_eliminate = NULL; )
DEBUG_ONLY( Node* disq_node = NULL; )
bool can_eliminate = true;
Node* res = alloc->result_cast();
const TypeOopPtr* res_type = NULL;
if (res == NULL) {
// All users were eliminated.
} else if (!res->is_CheckCastPP()) {
NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
can_eliminate = false;
} else {
res_type = _igvn.type(res)->isa_oopptr();
if (res_type == NULL) {
NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
can_eliminate = false;
} else if (res_type->isa_aryptr()) {
int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
if (length < 0) {
NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
can_eliminate = false;
}
}
}
if (can_eliminate && res != NULL) {
BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
for (DUIterator_Fast jmax, j = res->fast_outs(jmax);
j < jmax && can_eliminate; j++) {
Node* use = res->fast_out(j);
if (use->is_AddP()) {
const TypePtr* addp_type = _igvn.type(use)->is_ptr();
int offset = addp_type->offset();
if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
NOT_PRODUCT(fail_eliminate = "Undefined field reference";)
can_eliminate = false;
break;
}
for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
k < kmax && can_eliminate; k++) {
Node* n = use->fast_out(k);
if (!n->is_Store() && n->Opcode() != Op_CastP2X && !bs->is_gc_pre_barrier_node(n)) {
DEBUG_ONLY(disq_node = n;)
if (n->is_Load() || n->is_LoadStore()) {
NOT_PRODUCT(fail_eliminate = "Field load";)
} else {
NOT_PRODUCT(fail_eliminate = "Not store field reference";)
}
can_eliminate = false;
}
}
} else if (use->is_ArrayCopy() &&
(use->as_ArrayCopy()->is_clonebasic() ||
use->as_ArrayCopy()->is_arraycopy_validated() ||
use->as_ArrayCopy()->is_copyof_validated() ||
use->as_ArrayCopy()->is_copyofrange_validated()) &&
use->in(ArrayCopyNode::Dest) == res) {
// ok to eliminate
} else if (use->is_SafePoint()) {
SafePointNode* sfpt = use->as_SafePoint();
if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
// Object is passed as argument.
DEBUG_ONLY(disq_node = use;)
NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
can_eliminate = false;
}
Node* sfptMem = sfpt->memory();
if (sfptMem == NULL || sfptMem->is_top()) {
DEBUG_ONLY(disq_node = use;)
NOT_PRODUCT(fail_eliminate = "NULL or TOP memory";)
can_eliminate = false;
} else {
safepoints.append_if_missing(sfpt);
}
} else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
if (use->is_Phi()) {
if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
NOT_PRODUCT(fail_eliminate = "Object is return value";)
} else {
NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
}
DEBUG_ONLY(disq_node = use;)
} else {
if (use->Opcode() == Op_Return) {
NOT_PRODUCT(fail_eliminate = "Object is return value";)
}else {
NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
}
DEBUG_ONLY(disq_node = use;)
}
can_eliminate = false;
}
}
}
#ifndef PRODUCT
if (PrintEliminateAllocations) {
if (can_eliminate) {
tty->print("Scalar ");
if (res == NULL)
alloc->dump();
else
res->dump();
} else if (alloc->_is_scalar_replaceable) {
tty->print("NotScalar (%s)", fail_eliminate);
if (res == NULL)
alloc->dump();
else
res->dump();
#ifdef ASSERT
if (disq_node != NULL) {
tty->print(" >>>> ");
disq_node->dump();
}
#endif /*ASSERT*/
}
}
#endif
return can_eliminate;
}
// Do scalar replacement.
bool PhaseMacroExpand::scalar_replacement(AllocateNode *alloc, GrowableArray <SafePointNode *>& safepoints) {
GrowableArray <SafePointNode *> safepoints_done;
ciInstanceKlass* iklass = NULL;
int nfields = 0;
int array_base = 0;
int element_size = 0;
BasicType basic_elem_type = T_ILLEGAL;
const Type* field_type = NULL;
Node* res = alloc->result_cast();
assert(res == NULL || res->is_CheckCastPP(), "unexpected AllocateNode result");
const TypeOopPtr* res_type = NULL;
if (res != NULL) { // Could be NULL when there are no users
res_type = _igvn.type(res)->isa_oopptr();
}
if (res != NULL) {
if (res_type->isa_instptr()) {
// find the fields of the class which will be needed for safepoint debug information
iklass = res_type->is_instptr()->instance_klass();
nfields = iklass->nof_nonstatic_fields();
} else {
// find the array's elements which will be needed for safepoint debug information
nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
assert(nfields >= 0, "must be an array klass.");
basic_elem_type = res_type->is_aryptr()->elem()->array_element_basic_type();
array_base = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
element_size = type2aelembytes(basic_elem_type);
field_type = res_type->is_aryptr()->elem();
}
}
//
// Process the safepoint uses
//
while (safepoints.length() > 0) {
SafePointNode* sfpt = safepoints.pop();
Node* mem = sfpt->memory();
Node* ctl = sfpt->control();
assert(sfpt->jvms() != NULL, "missed JVMS");
// Fields of scalar objs are referenced only at the end
// of regular debuginfo at the last (youngest) JVMS.
// Record relative start index.
uint first_ind = (sfpt->req() - sfpt->jvms()->scloff());
SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type,
#ifdef ASSERT
alloc,
#endif
first_ind, nfields);
sobj->init_req(0, C->root());
transform_later(sobj);
// Scan object's fields adding an input to the safepoint for each field.
for (int j = 0; j < nfields; j++) {
intptr_t offset;
ciField* field = NULL;
if (iklass != NULL) {
field = iklass->nonstatic_field_at(j);
offset = field->offset();
ciType* elem_type = field->type();
basic_elem_type = field->layout_type();
// The next code is taken from Parse::do_get_xxx().
if (is_reference_type(basic_elem_type)) {
if (!elem_type->is_loaded()) {
field_type = TypeInstPtr::BOTTOM;
} else if (field != NULL && field->is_static_constant()) {
ciObject* con = field->constant_value().as_object();
// Do not "join" in the previous type; it doesn't add value,
// and may yield a vacuous result if the field is of interface type.
field_type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
assert(field_type != NULL, "field singleton type must be consistent");
} else {
field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
}
if (UseCompressedOops) {
field_type = field_type->make_narrowoop();
basic_elem_type = T_NARROWOOP;
}
} else {
field_type = Type::get_const_basic_type(basic_elem_type);
}
} else {
offset = array_base + j * (intptr_t)element_size;
}
const TypeOopPtr *field_addr_type = res_type->add_offset(offset)->isa_oopptr();
Node *field_val = value_from_mem(mem, ctl, basic_elem_type, field_type, field_addr_type, alloc);
if (field_val == NULL) {
// We weren't able to find a value for this field,
// give up on eliminating this allocation.
// Remove any extra entries we added to the safepoint.
uint last = sfpt->req() - 1;
for (int k = 0; k < j; k++) {
sfpt->del_req(last--);
}
_igvn._worklist.push(sfpt);
// rollback processed safepoints
while (safepoints_done.length() > 0) {
SafePointNode* sfpt_done = safepoints_done.pop();
// remove any extra entries we added to the safepoint
last = sfpt_done->req() - 1;
for (int k = 0; k < nfields; k++) {
sfpt_done->del_req(last--);
}
JVMState *jvms = sfpt_done->jvms();
jvms->set_endoff(sfpt_done->req());
// Now make a pass over the debug information replacing any references
// to SafePointScalarObjectNode with the allocated object.
int start = jvms->debug_start();
int end = jvms->debug_end();
for (int i = start; i < end; i++) {
if (sfpt_done->in(i)->is_SafePointScalarObject()) {
SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
if (scobj->first_index(jvms) == sfpt_done->req() &&
scobj->n_fields() == (uint)nfields) {
assert(scobj->alloc() == alloc, "sanity");
sfpt_done->set_req(i, res);
}
}
}
_igvn._worklist.push(sfpt_done);
}
#ifndef PRODUCT
if (PrintEliminateAllocations) {
if (field != NULL) {
tty->print("=== At SafePoint node %d can't find value of Field: ",
sfpt->_idx);
field->print();
int field_idx = C->get_alias_index(field_addr_type);
tty->print(" (alias_idx=%d)", field_idx);
} else { // Array's element
tty->print("=== At SafePoint node %d can't find value of array element [%d]",
sfpt->_idx, j);
}
tty->print(", which prevents elimination of: ");
if (res == NULL)
alloc->dump();
else
res->dump();
}
#endif
return false;
}
if (UseCompressedOops && field_type->isa_narrowoop()) {
// Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
// to be able scalar replace the allocation.
if (field_val->is_EncodeP()) {
field_val = field_val->in(1);
} else {
field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
}
}
sfpt->add_req(field_val);
}
JVMState *jvms = sfpt->jvms();
jvms->set_endoff(sfpt->req());
// Now make a pass over the debug information replacing any references
// to the allocated object with "sobj"
int start = jvms->debug_start();
int end = jvms->debug_end();
sfpt->replace_edges_in_range(res, sobj, start, end, &_igvn);
_igvn._worklist.push(sfpt);
safepoints_done.append_if_missing(sfpt); // keep it for rollback
}
return true;
}
static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
if (ctl_proj != NULL) {
igvn.replace_node(ctl_proj, n->in(0));
}
if (mem_proj != NULL) {
igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
}
}
// Process users of eliminated allocation.
void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc) {
Node* res = alloc->result_cast();
if (res != NULL) {
for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
Node *use = res->last_out(j);
uint oc1 = res->outcnt();
if (use->is_AddP()) {
for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
Node *n = use->last_out(k);
uint oc2 = use->outcnt();
if (n->is_Store()) {
#ifdef ASSERT
// Verify that there is no dependent MemBarVolatile nodes,
// they should be removed during IGVN, see MemBarNode::Ideal().
for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
p < pmax; p++) {
Node* mb = n->fast_out(p);
assert(mb->is_Initialize() || !mb->is_MemBar() ||
mb->req() <= MemBarNode::Precedent ||
mb->in(MemBarNode::Precedent) != n,
"MemBarVolatile should be eliminated for non-escaping object");
}
#endif
_igvn.replace_node(n, n->in(MemNode::Memory));
} else {
eliminate_gc_barrier(n);
}
k -= (oc2 - use->outcnt());
}
_igvn.remove_dead_node(use);
} else if (use->is_ArrayCopy()) {
// Disconnect ArrayCopy node
ArrayCopyNode* ac = use->as_ArrayCopy();
if (ac->is_clonebasic()) {
Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
disconnect_projections(ac, _igvn);
assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
disconnect_projections(membar_before->as_MemBar(), _igvn);
if (membar_after->is_MemBar()) {
disconnect_projections(membar_after->as_MemBar(), _igvn);
}
} else {
assert(ac->is_arraycopy_validated() ||
ac->is_copyof_validated() ||
ac->is_copyofrange_validated(), "unsupported");
CallProjections callprojs;
ac->extract_projections(&callprojs, true);
_igvn.replace_node(callprojs.fallthrough_ioproj, ac->in(TypeFunc::I_O));
_igvn.replace_node(callprojs.fallthrough_memproj, ac->in(TypeFunc::Memory));
_igvn.replace_node(callprojs.fallthrough_catchproj, ac->in(TypeFunc::Control));
// Set control to top. IGVN will remove the remaining projections
ac->set_req(0, top());
ac->replace_edge(res, top(), &_igvn);
// Disconnect src right away: it can help find new
// opportunities for allocation elimination
Node* src = ac->in(ArrayCopyNode::Src);
ac->replace_edge(src, top(), &_igvn);
// src can be top at this point if src and dest of the
// arraycopy were the same
if (src->outcnt() == 0 && !src->is_top()) {
_igvn.remove_dead_node(src);
}
}
_igvn._worklist.push(ac);
} else {
eliminate_gc_barrier(use);
}
j -= (oc1 - res->outcnt());
}
assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
_igvn.remove_dead_node(res);
}
//
// Process other users of allocation's projections
//
if (_callprojs.resproj != NULL && _callprojs.resproj->outcnt() != 0) {
// First disconnect stores captured by Initialize node.
// If Initialize node is eliminated first in the following code,
// it will kill such stores and DUIterator_Last will assert.
for (DUIterator_Fast jmax, j = _callprojs.resproj->fast_outs(jmax); j < jmax; j++) {
Node* use = _callprojs.resproj->fast_out(j);
if (use->is_AddP()) {
// raw memory addresses used only by the initialization
_igvn.replace_node(use, C->top());
--j; --jmax;
}
}
for (DUIterator_Last jmin, j = _callprojs.resproj->last_outs(jmin); j >= jmin; ) {
Node* use = _callprojs.resproj->last_out(j);
uint oc1 = _callprojs.resproj->outcnt();
if (use->is_Initialize()) {
// Eliminate Initialize node.
InitializeNode *init = use->as_Initialize();
assert(init->outcnt() <= 2, "only a control and memory projection expected");
Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
if (ctrl_proj != NULL) {
_igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
#ifdef ASSERT
// If the InitializeNode has no memory out, it will die, and tmp will become NULL
Node* tmp = init->in(TypeFunc::Control);
assert(tmp == NULL || tmp == _callprojs.fallthrough_catchproj, "allocation control projection");
#endif
}
Node *mem_proj = init->proj_out_or_null(TypeFunc::Memory);
if (mem_proj != NULL) {
Node *mem = init->in(TypeFunc::Memory);
#ifdef ASSERT
if (mem->is_MergeMem()) {
assert(mem->in(TypeFunc::Memory) == _callprojs.fallthrough_memproj, "allocation memory projection");
} else {
assert(mem == _callprojs.fallthrough_memproj, "allocation memory projection");
}
#endif
_igvn.replace_node(mem_proj, mem);
}
} else {
assert(false, "only Initialize or AddP expected");
}
j -= (oc1 - _callprojs.resproj->outcnt());
}
}
if (_callprojs.fallthrough_catchproj != NULL) {
_igvn.replace_node(_callprojs.fallthrough_catchproj, alloc->in(TypeFunc::Control));
}
if (_callprojs.fallthrough_memproj != NULL) {
_igvn.replace_node(_callprojs.fallthrough_memproj, alloc->in(TypeFunc::Memory));
}
if (_callprojs.catchall_memproj != NULL) {
_igvn.replace_node(_callprojs.catchall_memproj, C->top());
}
if (_callprojs.fallthrough_ioproj != NULL) {
_igvn.replace_node(_callprojs.fallthrough_ioproj, alloc->in(TypeFunc::I_O));
}
if (_callprojs.catchall_ioproj != NULL) {
_igvn.replace_node(_callprojs.catchall_ioproj, C->top());
}
if (_callprojs.catchall_catchproj != NULL) {
_igvn.replace_node(_callprojs.catchall_catchproj, C->top());
}
}
bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
// If reallocation fails during deoptimization we'll pop all
// interpreter frames for this compiled frame and that won't play
// nice with JVMTI popframe.
// We avoid this issue by eager reallocation when the popframe request
// is received.
if (!EliminateAllocations || !alloc->_is_non_escaping) {
return false;
}
Node* klass = alloc->in(AllocateNode::KlassNode);
const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
Node* res = alloc->result_cast();
// Eliminate boxing allocations which are not used
// regardless scalar replaceable status.
bool boxing_alloc = C->eliminate_boxing() &&
tklass->isa_instklassptr() &&
tklass->is_instklassptr()->instance_klass()->is_box_klass();
if (!alloc->_is_scalar_replaceable && (!boxing_alloc || (res != NULL))) {
return false;
}
alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
GrowableArray <SafePointNode *> safepoints;
if (!can_eliminate_allocation(alloc, safepoints)) {
return false;
}
if (!alloc->_is_scalar_replaceable) {
assert(res == NULL, "sanity");
// We can only eliminate allocation if all debug info references
// are already replaced with SafePointScalarObject because
// we can't search for a fields value without instance_id.
if (safepoints.length() > 0) {
return false;
}
}
if (!scalar_replacement(alloc, safepoints)) {
return false;
}
CompileLog* log = C->log();
if (log != NULL) {
log->head("eliminate_allocation type='%d'",
log->identify(tklass->exact_klass()));
JVMState* p = alloc->jvms();
while (p != NULL) {
log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
p = p->caller();
}
log->tail("eliminate_allocation");
}
process_users_of_allocation(alloc);
#ifndef PRODUCT
if (PrintEliminateAllocations) {
if (alloc->is_AllocateArray())
tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
else
tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
}
#endif
return true;
}
bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
// EA should remove all uses of non-escaping boxing node.
if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != NULL) {
return false;
}
assert(boxing->result_cast() == NULL, "unexpected boxing node result");
boxing->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
const TypeTuple* r = boxing->tf()->range();
assert(r->cnt() > TypeFunc::Parms, "sanity");
const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
assert(t != NULL, "sanity");
CompileLog* log = C->log();
if (log != NULL) {
log->head("eliminate_boxing type='%d'",
log->identify(t->instance_klass()));
JVMState* p = boxing->jvms();
while (p != NULL) {
log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
p = p->caller();
}
log->tail("eliminate_boxing");
}
process_users_of_allocation(boxing);
#ifndef PRODUCT
if (PrintEliminateAllocations) {
tty->print("++++ Eliminated: %d ", boxing->_idx);
boxing->method()->print_short_name(tty);
tty->cr();
}
#endif
return true;
}
Node* PhaseMacroExpand::make_load(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
Node* adr = basic_plus_adr(base, offset);
const TypePtr* adr_type = adr->bottom_type()->is_ptr();
Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
transform_later(value);
return value;
}
Node* PhaseMacroExpand::make_store(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
Node* adr = basic_plus_adr(base, offset);
mem = StoreNode::make(_igvn, ctl, mem, adr, NULL, value, bt, MemNode::unordered);
transform_later(mem);
return mem;
}
//=============================================================================
//
// A L L O C A T I O N
//
// Allocation attempts to be fast in the case of frequent small objects.
// It breaks down like this:
//
// 1) Size in doublewords is computed. This is a constant for objects and
// variable for most arrays. Doubleword units are used to avoid size
// overflow of huge doubleword arrays. We need doublewords in the end for
// rounding.
//
// 2) Size is checked for being 'too large'. Too-large allocations will go
// the slow path into the VM. The slow path can throw any required
// exceptions, and does all the special checks for very large arrays. The
// size test can constant-fold away for objects. For objects with
// finalizers it constant-folds the otherway: you always go slow with
// finalizers.
//
// 3) If NOT using TLABs, this is the contended loop-back point.
// Load-Locked the heap top. If using TLABs normal-load the heap top.
//
// 4) Check that heap top + size*8 < max. If we fail go the slow ` route.
// NOTE: "top+size*8" cannot wrap the 4Gig line! Here's why: for largish
// "size*8" we always enter the VM, where "largish" is a constant picked small
// enough that there's always space between the eden max and 4Gig (old space is
// there so it's quite large) and large enough that the cost of entering the VM
// is dwarfed by the cost to initialize the space.
//
// 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
// down. If contended, repeat at step 3. If using TLABs normal-store
// adjusted heap top back down; there is no contention.
//
// 6) If !ZeroTLAB then Bulk-clear the object/array. Fill in klass & mark
// fields.
//
// 7) Merge with the slow-path; cast the raw memory pointer to the correct
// oop flavor.
//
//=============================================================================
// FastAllocateSizeLimit value is in DOUBLEWORDS.
// Allocations bigger than this always go the slow route.
// This value must be small enough that allocation attempts that need to
// trigger exceptions go the slow route. Also, it must be small enough so
// that heap_top + size_in_bytes does not wrap around the 4Gig limit.
//=============================================================================j//
// %%% Here is an old comment from parseHelper.cpp; is it outdated?
// The allocator will coalesce int->oop copies away. See comment in
// coalesce.cpp about how this works. It depends critically on the exact
// code shape produced here, so if you are changing this code shape
// make sure the GC info for the heap-top is correct in and around the
// slow-path call.
//
void PhaseMacroExpand::expand_allocate_common(
AllocateNode* alloc, // allocation node to be expanded
Node* length, // array length for an array allocation
const TypeFunc* slow_call_type, // Type of slow call
address slow_call_address, // Address of slow call
Node* valid_length_test // whether length is valid or not
)
{
Node* ctrl = alloc->in(TypeFunc::Control);
Node* mem = alloc->in(TypeFunc::Memory);
Node* i_o = alloc->in(TypeFunc::I_O);
Node* size_in_bytes = alloc->in(AllocateNode::AllocSize);
Node* klass_node = alloc->in(AllocateNode::KlassNode);
Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
assert(ctrl != NULL, "must have control");
// We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
// they will not be used if "always_slow" is set
enum { slow_result_path = 1, fast_result_path = 2 };
Node *result_region = NULL;
Node *result_phi_rawmem = NULL;
Node *result_phi_rawoop = NULL;
Node *result_phi_i_o = NULL;
// The initial slow comparison is a size check, the comparison
// we want to do is a BoolTest::gt
bool expand_fast_path = true;
int tv = _igvn.find_int_con(initial_slow_test, -1);
if (tv >= 0) {
// InitialTest has constant result
// 0 - can fit in TLAB
// 1 - always too big or negative
assert(tv <= 1, "0 or 1 if a constant");
expand_fast_path = (tv == 0);
initial_slow_test = NULL;
} else {
initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
}
if (!UseTLAB) {
// Force slow-path allocation
expand_fast_path = false;
initial_slow_test = NULL;
}
bool allocation_has_use = (alloc->result_cast() != NULL);
if (!allocation_has_use) {
InitializeNode* init = alloc->initialization();
if (init != NULL) {
init->remove(&_igvn);
}
if (expand_fast_path && (initial_slow_test == NULL)) {
// Remove allocation node and return.
// Size is a non-negative constant -> no initial check needed -> directly to fast path.
// Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
#ifndef PRODUCT
if (PrintEliminateAllocations) {
tty->print("NotUsed ");
Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
if (res != NULL) {
res->dump();
} else {
alloc->dump();
}
}
#endif
yank_alloc_node(alloc);
return;
}
}
enum { too_big_or_final_path = 1, need_gc_path = 2 };
Node *slow_region = NULL;
Node *toobig_false = ctrl;
// generate the initial test if necessary
if (initial_slow_test != NULL ) {
assert (expand_fast_path, "Only need test if there is a fast path");
slow_region = new RegionNode(3);
// Now make the initial failure test. Usually a too-big test but
// might be a TRUE for finalizers or a fancy class check for
// newInstance0.
IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
transform_later(toobig_iff);
// Plug the failing-too-big test into the slow-path region
Node *toobig_true = new IfTrueNode( toobig_iff );
transform_later(toobig_true);
slow_region ->init_req( too_big_or_final_path, toobig_true );
toobig_false = new IfFalseNode( toobig_iff );
transform_later(toobig_false);
} else {
// No initial test, just fall into next case
assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
toobig_false = ctrl;
debug_only(slow_region = NodeSentinel);
}
// If we are here there are several possibilities
// - expand_fast_path is false - then only a slow path is expanded. That's it.
// no_initial_check means a constant allocation.
// - If check always evaluates to false -> expand_fast_path is false (see above)
// - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
// if !allocation_has_use the fast path is empty
// if !allocation_has_use && no_initial_check
// - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
// removed by yank_alloc_node above.
Node *slow_mem = mem; // save the current memory state for slow path
// generate the fast allocation code unless we know that the initial test will always go slow
if (expand_fast_path) {
// Fast path modifies only raw memory.
if (mem->is_MergeMem()) {
mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
}
// allocate the Region and Phi nodes for the result
result_region = new RegionNode(3);
result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
result_phi_i_o = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
// Grab regular I/O before optional prefetch may change it.
// Slow-path does no I/O so just set it to the original I/O.
result_phi_i_o->init_req(slow_result_path, i_o);
// Name successful fast-path variables
Node* fast_oop_ctrl;
Node* fast_oop_rawmem;
if (allocation_has_use) {
Node* needgc_ctrl = NULL;
result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
intx prefetch_lines = length != NULL ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
fast_oop_ctrl, fast_oop_rawmem,
prefetch_lines);
if (initial_slow_test != NULL) {
// This completes all paths into the slow merge point
slow_region->init_req(need_gc_path, needgc_ctrl);
transform_later(slow_region);
} else {
// No initial slow path needed!
// Just fall from the need-GC path straight into the VM call.
slow_region = needgc_ctrl;
}
InitializeNode* init = alloc->initialization();
fast_oop_rawmem = initialize_object(alloc,
fast_oop_ctrl, fast_oop_rawmem, fast_oop,
klass_node, length, size_in_bytes);
expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
result_phi_rawoop->init_req(fast_result_path, fast_oop);
} else {
assert (initial_slow_test != NULL, "sanity");
fast_oop_ctrl = toobig_false;
fast_oop_rawmem = mem;
transform_later(slow_region);
}
// Plug in the successful fast-path into the result merge point
result_region ->init_req(fast_result_path, fast_oop_ctrl);
result_phi_i_o ->init_req(fast_result_path, i_o);
result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
} else {
slow_region = ctrl;
result_phi_i_o = i_o; // Rename it to use in the following code.
}
// Generate slow-path call
CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
OptoRuntime::stub_name(slow_call_address),
TypePtr::BOTTOM);
call->init_req(TypeFunc::Control, slow_region);
call->init_req(TypeFunc::I_O, top()); // does no i/o
call->init_req(TypeFunc::Memory, slow_mem); // may gc ptrs
call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
call->init_req(TypeFunc::Parms+0, klass_node);
if (length != NULL) {
call->init_req(TypeFunc::Parms+1, length);
}
// Copy debug information and adjust JVMState information, then replace
// allocate node with the call
call->copy_call_debug_info(&_igvn, alloc);
// For array allocations, copy the valid length check to the call node so Compile::final_graph_reshaping() can verify
// that the call has the expected number of CatchProj nodes (in case the allocation always fails and the fallthrough
// path dies).
if (valid_length_test != NULL) {
call->add_req(valid_length_test);
}
if (expand_fast_path) {
call->set_cnt(PROB_UNLIKELY_MAG(4)); // Same effect as RC_UNCOMMON.
} else {
// Hook i_o projection to avoid its elimination during allocation
// replacement (when only a slow call is generated).
call->set_req(TypeFunc::I_O, result_phi_i_o);
}
_igvn.replace_node(alloc, call);
transform_later(call);
// Identify the output projections from the allocate node and
// adjust any references to them.
// The control and io projections look like:
//
// v---Proj(ctrl) <-----+ v---CatchProj(ctrl)
// Allocate Catch
// ^---Proj(io) <-------+ ^---CatchProj(io)
//
// We are interested in the CatchProj nodes.
//
call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
// An allocate node has separate memory projections for the uses on
// the control and i_o paths. Replace the control memory projection with
// result_phi_rawmem (unless we are only generating a slow call when
// both memory projections are combined)
if (expand_fast_path && _callprojs.fallthrough_memproj != NULL) {
migrate_outs(_callprojs.fallthrough_memproj, result_phi_rawmem);
}
// Now change uses of catchall_memproj to use fallthrough_memproj and delete
// catchall_memproj so we end up with a call that has only 1 memory projection.
if (_callprojs.catchall_memproj != NULL ) {
if (_callprojs.fallthrough_memproj == NULL) {
_callprojs.fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
transform_later(_callprojs.fallthrough_memproj);
}
migrate_outs(_callprojs.catchall_memproj, _callprojs.fallthrough_memproj);
_igvn.remove_dead_node(_callprojs.catchall_memproj);
}
// An allocate node has separate i_o projections for the uses on the control
// and i_o paths. Always replace the control i_o projection with result i_o
// otherwise incoming i_o become dead when only a slow call is generated
// (it is different from memory projections where both projections are
// combined in such case).
if (_callprojs.fallthrough_ioproj != NULL) {
migrate_outs(_callprojs.fallthrough_ioproj, result_phi_i_o);
}
// Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
// catchall_ioproj so we end up with a call that has only 1 i_o projection.
if (_callprojs.catchall_ioproj != NULL ) {
if (_callprojs.fallthrough_ioproj == NULL) {
_callprojs.fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
transform_later(_callprojs.fallthrough_ioproj);
}
migrate_outs(_callprojs.catchall_ioproj, _callprojs.fallthrough_ioproj);
_igvn.remove_dead_node(_callprojs.catchall_ioproj);
}
// if we generated only a slow call, we are done
if (!expand_fast_path) {
// Now we can unhook i_o.
if (result_phi_i_o->outcnt() > 1) {
call->set_req(TypeFunc::I_O, top());
} else {
assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
// Case of new array with negative size known during compilation.
// AllocateArrayNode::Ideal() optimization disconnect unreachable
// following code since call to runtime will throw exception.
// As result there will be no users of i_o after the call.
// Leave i_o attached to this call to avoid problems in preceding graph.
}
return;
}
if (_callprojs.fallthrough_catchproj != NULL) {
ctrl = _callprojs.fallthrough_catchproj->clone();
transform_later(ctrl);
_igvn.replace_node(_callprojs.fallthrough_catchproj, result_region);
} else {
ctrl = top();
}
Node *slow_result;
if (_callprojs.resproj == NULL) {
// no uses of the allocation result
slow_result = top();
} else {
slow_result = _callprojs.resproj->clone();
transform_later(slow_result);
_igvn.replace_node(_callprojs.resproj, result_phi_rawoop);
}
// Plug slow-path into result merge point
result_region->init_req( slow_result_path, ctrl);
transform_later(result_region);
if (allocation_has_use) {
result_phi_rawoop->init_req(slow_result_path, slow_result);
transform_later(result_phi_rawoop);
}
result_phi_rawmem->init_req(slow_result_path, _callprojs.fallthrough_memproj);
transform_later(result_phi_rawmem);
transform_later(result_phi_i_o);
// This completes all paths into the result merge point
}
// Remove alloc node that has no uses.
void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
Node* ctrl = alloc->in(TypeFunc::Control);
Node* mem = alloc->in(TypeFunc::Memory);
Node* i_o = alloc->in(TypeFunc::I_O);
alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
if (_callprojs.resproj != NULL) {
for (DUIterator_Fast imax, i = _callprojs.resproj->fast_outs(imax); i < imax; i++) {
Node* use = _callprojs.resproj->fast_out(i);
use->isa_MemBar()->remove(&_igvn);
--imax;
--i; // back up iterator
}
assert(_callprojs.resproj->outcnt() == 0, "all uses must be deleted");
_igvn.remove_dead_node(_callprojs.resproj);
}
if (_callprojs.fallthrough_catchproj != NULL) {
migrate_outs(_callprojs.fallthrough_catchproj, ctrl);
_igvn.remove_dead_node(_callprojs.fallthrough_catchproj);
}
if (_callprojs.catchall_catchproj != NULL) {
_igvn.rehash_node_delayed(_callprojs.catchall_catchproj);
_callprojs.catchall_catchproj->set_req(0, top());
}
if (_callprojs.fallthrough_proj != NULL) {
Node* catchnode = _callprojs.fallthrough_proj->unique_ctrl_out();
_igvn.remove_dead_node(catchnode);
_igvn.remove_dead_node(_callprojs.fallthrough_proj);
}
if (_callprojs.fallthrough_memproj != NULL) {
migrate_outs(_callprojs.fallthrough_memproj, mem);
_igvn.remove_dead_node(_callprojs.fallthrough_memproj);
}
if (_callprojs.fallthrough_ioproj != NULL) {
migrate_outs(_callprojs.fallthrough_ioproj, i_o);
_igvn.remove_dead_node(_callprojs.fallthrough_ioproj);
}
if (_callprojs.catchall_memproj != NULL) {
_igvn.rehash_node_delayed(_callprojs.catchall_memproj);
_callprojs.catchall_memproj->set_req(0, top());
}
if (_callprojs.catchall_ioproj != NULL) {
_igvn.rehash_node_delayed(_callprojs.catchall_ioproj);
_callprojs.catchall_ioproj->set_req(0, top());
}
#ifndef PRODUCT
if (PrintEliminateAllocations) {
if (alloc->is_AllocateArray()) {
tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
} else {
tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
}
}
#endif
_igvn.remove_dead_node(alloc);
}
void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
// If initialization is performed by an array copy, any required
// MemBarStoreStore was already added. If the object does not
// escape no need for a MemBarStoreStore. If the object does not
// escape in its initializer and memory barrier (MemBarStoreStore or
// stronger) is already added at exit of initializer, also no need
// for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
// so that stores that initialize this object can't be reordered
// with a subsequent store that makes this object accessible by
// other threads.
// Other threads include java threads and JVM internal threads
// (for example concurrent GC threads). Current concurrent GC
// implementation: G1 will not scan newly created object,
// so it's safe to skip storestore barrier when allocation does
// not escape.
if (!alloc->does_not_escape_thread() &&
!alloc->is_allocation_MemBar_redundant() &&
(init == NULL || !init->is_complete_with_arraycopy())) {
if (init == NULL || init->req() < InitializeNode::RawStores) {
// No InitializeNode or no stores captured by zeroing
// elimination. Simply add the MemBarStoreStore after object
// initialization.
MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
transform_later(mb);
mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
mb->init_req(TypeFunc::Control, fast_oop_ctrl);
fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
transform_later(fast_oop_ctrl);
fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
transform_later(fast_oop_rawmem);
} else {
// Add the MemBarStoreStore after the InitializeNode so that
// all stores performing the initialization that were moved
// before the InitializeNode happen before the storestore
// barrier.
Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
Node* init_mem = init->proj_out_or_null(TypeFunc::Memory);
MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxBot);
transform_later(mb);
Node* ctrl = new ProjNode(init, TypeFunc::Control);
transform_later(ctrl);
Node* mem = new ProjNode(init, TypeFunc::Memory);
transform_later(mem);
// The MemBarStoreStore depends on control and memory coming
// from the InitializeNode
mb->init_req(TypeFunc::Memory, mem);
mb->init_req(TypeFunc::Control, ctrl);
ctrl = new ProjNode(mb, TypeFunc::Control);
transform_later(ctrl);
mem = new ProjNode(mb, TypeFunc::Memory);
transform_later(mem);
// All nodes that depended on the InitializeNode for control
// and memory must now depend on the MemBarNode that itself
// depends on the InitializeNode
if (init_ctrl != NULL) {
_igvn.replace_node(init_ctrl, ctrl);
}
if (init_mem != NULL) {
_igvn.replace_node(init_mem, mem);
}
}
}
}
void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
Node*& ctrl, Node*& rawmem) {
if (C->env()->dtrace_alloc_probes()) {
// Slow-path call
int size = TypeFunc::Parms + 2;
CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
CAST_FROM_FN_PTR(address,
static_cast<int (*)(JavaThread*, oopDesc*)>(SharedRuntime::dtrace_object_alloc)),
"dtrace_object_alloc",
TypeRawPtr::BOTTOM);
// Get base of thread-local storage area
Node* thread = new ThreadLocalNode();
transform_later(thread);
call->init_req(TypeFunc::Parms + 0, thread);
call->init_req(TypeFunc::Parms + 1, oop);
call->init_req(TypeFunc::Control, ctrl);
--> --------------------
--> maximum size reached
--> --------------------
¤ Dauer der Verarbeitung: 0.57 Sekunden
(vorverarbeitet)
¤
|
Haftungshinweis
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung ist noch experimentell.
|
