8218874: C2: Unsafe to access PhaseIdealLoop outside of constructors
Reviewed-by: thartmann, kvn
/*
* Copyright (c) 2015, 2019, 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.
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*/
#include "precompiled.hpp"
#include "opto/compile.hpp"
#include "opto/castnode.hpp"
#include "opto/escape.hpp"
#include "opto/graphKit.hpp"
#include "opto/idealKit.hpp"
#include "opto/loopnode.hpp"
#include "opto/macro.hpp"
#include "opto/node.hpp"
#include "opto/type.hpp"
#include "utilities/macros.hpp"
#include "gc/z/zBarrierSet.hpp"
#include "gc/z/c2/zBarrierSetC2.hpp"
#include "gc/z/zThreadLocalData.hpp"
#include "gc/z/zBarrierSetRuntime.hpp"
ZBarrierSetC2State::ZBarrierSetC2State(Arena* comp_arena) :
_load_barrier_nodes(new (comp_arena) GrowableArray<LoadBarrierNode*>(comp_arena, 8, 0, NULL)) {}
int ZBarrierSetC2State::load_barrier_count() const {
return _load_barrier_nodes->length();
}
void ZBarrierSetC2State::add_load_barrier_node(LoadBarrierNode * n) {
assert(!_load_barrier_nodes->contains(n), " duplicate entry in expand list");
_load_barrier_nodes->append(n);
}
void ZBarrierSetC2State::remove_load_barrier_node(LoadBarrierNode * n) {
// this function may be called twice for a node so check
// that the node is in the array before attempting to remove it
if (_load_barrier_nodes->contains(n)) {
_load_barrier_nodes->remove(n);
}
}
LoadBarrierNode* ZBarrierSetC2State::load_barrier_node(int idx) const {
return _load_barrier_nodes->at(idx);
}
void* ZBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
return new(comp_arena) ZBarrierSetC2State(comp_arena);
}
ZBarrierSetC2State* ZBarrierSetC2::state() const {
return reinterpret_cast<ZBarrierSetC2State*>(Compile::current()->barrier_set_state());
}
bool ZBarrierSetC2::is_gc_barrier_node(Node* node) const {
// 1. This step follows potential oop projections of a load barrier before expansion
if (node->is_Proj()) {
node = node->in(0);
}
// 2. This step checks for unexpanded load barriers
if (node->is_LoadBarrier()) {
return true;
}
// 3. This step checks for the phi corresponding to an optimized load barrier expansion
if (node->is_Phi()) {
PhiNode* phi = node->as_Phi();
Node* n = phi->in(1);
if (n != NULL && (n->is_LoadBarrierSlowReg() || n->is_LoadBarrierWeakSlowReg())) {
return true;
}
}
return false;
}
void ZBarrierSetC2::register_potential_barrier_node(Node* node) const {
if (node->is_LoadBarrier()) {
state()->add_load_barrier_node(node->as_LoadBarrier());
}
}
void ZBarrierSetC2::unregister_potential_barrier_node(Node* node) const {
if (node->is_LoadBarrier()) {
state()->remove_load_barrier_node(node->as_LoadBarrier());
}
}
void ZBarrierSetC2::eliminate_useless_gc_barriers(Unique_Node_List &useful, Compile* C) const {
// Remove useless LoadBarrier nodes
ZBarrierSetC2State* s = state();
for (int i = s->load_barrier_count()-1; i >= 0; i--) {
LoadBarrierNode* n = s->load_barrier_node(i);
if (!useful.member(n)) {
unregister_potential_barrier_node(n);
}
}
}
void ZBarrierSetC2::enqueue_useful_gc_barrier(PhaseIterGVN* igvn, Node* node) const {
if (node->is_LoadBarrier() && !node->as_LoadBarrier()->has_true_uses()) {
igvn->_worklist.push(node);
}
}
void ZBarrierSetC2::find_dominating_barriers(PhaseIterGVN& igvn) {
// Look for dominating barriers on the same address only once all
// other loop opts are over. Loop opts may cause a safepoint to be
// inserted between a barrier and its dominating barrier.
Compile* C = Compile::current();
ZBarrierSetC2* bs = (ZBarrierSetC2*)BarrierSet::barrier_set()->barrier_set_c2();
ZBarrierSetC2State* s = bs->state();
if (s->load_barrier_count() >= 2) {
Compile::TracePhase tp("idealLoop", &C->timers[Phase::_t_idealLoop]);
PhaseIdealLoop::optimize(igvn, LoopOptsLastRound);
if (C->major_progress()) C->print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
}
}
void ZBarrierSetC2::add_users_to_worklist(Unique_Node_List* worklist) const {
// Permanent temporary workaround
// Loadbarriers may have non-obvious dead uses keeping them alive during parsing. The use is
// removed by RemoveUseless (after parsing, before optimize) but the barriers won't be added to
// the worklist. Unless we add them explicitly they are not guaranteed to end up there.
ZBarrierSetC2State* s = state();
for (int i = 0; i < s->load_barrier_count(); i++) {
LoadBarrierNode* n = s->load_barrier_node(i);
worklist->push(n);
}
}
const TypeFunc* ZBarrierSetC2::load_barrier_Type() const {
const Type** fields;
// Create input types (domain)
fields = TypeTuple::fields(2);
fields[TypeFunc::Parms+0] = TypeInstPtr::NOTNULL;
fields[TypeFunc::Parms+1] = TypeOopPtr::BOTTOM;
const TypeTuple *domain = TypeTuple::make(TypeFunc::Parms+2, fields);
// Create result type (range)
fields = TypeTuple::fields(1);
fields[TypeFunc::Parms+0] = TypeInstPtr::BOTTOM;
const TypeTuple *range = TypeTuple::make(TypeFunc::Parms+1, fields);
return TypeFunc::make(domain, range);
}
// == LoadBarrierNode ==
LoadBarrierNode::LoadBarrierNode(Compile* C,
Node* c,
Node* mem,
Node* val,
Node* adr,
bool weak,
bool writeback,
bool oop_reload_allowed) :
MultiNode(Number_of_Inputs),
_weak(weak),
_writeback(writeback),
_oop_reload_allowed(oop_reload_allowed) {
init_req(Control, c);
init_req(Memory, mem);
init_req(Oop, val);
init_req(Address, adr);
init_req(Similar, C->top());
init_class_id(Class_LoadBarrier);
BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
bs->register_potential_barrier_node(this);
}
uint LoadBarrierNode::size_of() const {
return sizeof(*this);
}
uint LoadBarrierNode::cmp(const Node& n) const {
ShouldNotReachHere();
return 0;
}
const Type *LoadBarrierNode::bottom_type() const {
const Type** floadbarrier = (const Type **)(Compile::current()->type_arena()->Amalloc_4((Number_of_Outputs)*sizeof(Type*)));
Node* in_oop = in(Oop);
floadbarrier[Control] = Type::CONTROL;
floadbarrier[Memory] = Type::MEMORY;
floadbarrier[Oop] = in_oop == NULL ? Type::TOP : in_oop->bottom_type();
return TypeTuple::make(Number_of_Outputs, floadbarrier);
}
const TypePtr* LoadBarrierNode::adr_type() const {
ShouldNotReachHere();
return NULL;
}
const Type *LoadBarrierNode::Value(PhaseGVN *phase) const {
const Type** floadbarrier = (const Type **)(phase->C->type_arena()->Amalloc_4((Number_of_Outputs)*sizeof(Type*)));
const Type* val_t = phase->type(in(Oop));
floadbarrier[Control] = Type::CONTROL;
floadbarrier[Memory] = Type::MEMORY;
floadbarrier[Oop] = val_t;
return TypeTuple::make(Number_of_Outputs, floadbarrier);
}
bool LoadBarrierNode::is_dominator(PhaseIdealLoop* phase, bool linear_only, Node *d, Node *n) {
if (phase != NULL) {
return phase->is_dominator(d, n);
}
for (int i = 0; i < 10 && n != NULL; i++) {
n = IfNode::up_one_dom(n, linear_only);
if (n == d) {
return true;
}
}
return false;
}
LoadBarrierNode* LoadBarrierNode::has_dominating_barrier(PhaseIdealLoop* phase, bool linear_only, bool look_for_similar) {
Node* val = in(LoadBarrierNode::Oop);
if (in(Similar)->is_Proj() && in(Similar)->in(0)->is_LoadBarrier()) {
LoadBarrierNode* lb = in(Similar)->in(0)->as_LoadBarrier();
assert(lb->in(Address) == in(Address), "");
// Load barrier on Similar edge dominates so if it now has the Oop field it can replace this barrier.
if (lb->in(Oop) == in(Oop)) {
return lb;
}
// Follow chain of load barrier through Similar edges
while (!lb->in(Similar)->is_top()) {
lb = lb->in(Similar)->in(0)->as_LoadBarrier();
assert(lb->in(Address) == in(Address), "");
}
if (lb != in(Similar)->in(0)) {
return lb;
}
}
for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
Node* u = val->fast_out(i);
if (u != this && u->is_LoadBarrier() && u->in(Oop) == val && u->as_LoadBarrier()->has_true_uses()) {
Node* this_ctrl = in(LoadBarrierNode::Control);
Node* other_ctrl = u->in(LoadBarrierNode::Control);
if (is_dominator(phase, linear_only, other_ctrl, this_ctrl)) {
return u->as_LoadBarrier();
}
}
}
if (ZVerifyLoadBarriers || can_be_eliminated()) {
return NULL;
}
if (!look_for_similar) {
return NULL;
}
Node* addr = in(LoadBarrierNode::Address);
for (DUIterator_Fast imax, i = addr->fast_outs(imax); i < imax; i++) {
Node* u = addr->fast_out(i);
if (u != this && u->is_LoadBarrier() && u->as_LoadBarrier()->has_true_uses()) {
Node* this_ctrl = in(LoadBarrierNode::Control);
Node* other_ctrl = u->in(LoadBarrierNode::Control);
if (is_dominator(phase, linear_only, other_ctrl, this_ctrl)) {
ResourceMark rm;
Unique_Node_List wq;
wq.push(in(LoadBarrierNode::Control));
bool ok = true;
bool dom_found = false;
for (uint next = 0; next < wq.size(); ++next) {
Node *n = wq.at(next);
if (n->is_top()) {
return NULL;
}
assert(n->is_CFG(), "");
if (n->is_SafePoint()) {
ok = false;
break;
}
if (n == u) {
dom_found = true;
continue;
}
if (n->is_Region()) {
for (uint i = 1; i < n->req(); i++) {
Node* m = n->in(i);
if (m != NULL) {
wq.push(m);
}
}
} else {
Node* m = n->in(0);
if (m != NULL) {
wq.push(m);
}
}
}
if (ok) {
assert(dom_found, "");
return u->as_LoadBarrier();;
}
break;
}
}
}
return NULL;
}
void LoadBarrierNode::push_dominated_barriers(PhaseIterGVN* igvn) const {
// Change to that barrier may affect a dominated barrier so re-push those
Node* val = in(LoadBarrierNode::Oop);
for (DUIterator_Fast imax, i = val->fast_outs(imax); i < imax; i++) {
Node* u = val->fast_out(i);
if (u != this && u->is_LoadBarrier() && u->in(Oop) == val) {
Node* this_ctrl = in(Control);
Node* other_ctrl = u->in(Control);
if (is_dominator(NULL, false, this_ctrl, other_ctrl)) {
igvn->_worklist.push(u);
}
}
Node* addr = in(LoadBarrierNode::Address);
for (DUIterator_Fast imax, i = addr->fast_outs(imax); i < imax; i++) {
Node* u = addr->fast_out(i);
if (u != this && u->is_LoadBarrier() && u->in(Similar)->is_top()) {
Node* this_ctrl = in(Control);
Node* other_ctrl = u->in(Control);
if (is_dominator(NULL, false, this_ctrl, other_ctrl)) {
igvn->_worklist.push(u);
}
}
}
}
}
Node *LoadBarrierNode::Identity(PhaseGVN *phase) {
if (!phase->C->directive()->ZOptimizeLoadBarriersOption) {
return this;
}
bool redundant_addr = false;
LoadBarrierNode* dominating_barrier = has_dominating_barrier(NULL, true, false);
if (dominating_barrier != NULL) {
assert(dominating_barrier->in(Oop) == in(Oop), "");
return dominating_barrier;
}
return this;
}
Node *LoadBarrierNode::Ideal(PhaseGVN *phase, bool can_reshape) {
if (remove_dead_region(phase, can_reshape)) {
return this;
}
Node* val = in(Oop);
Node* mem = in(Memory);
Node* ctrl = in(Control);
Node* adr = in(Address);
assert(val->Opcode() != Op_LoadN, "");
if (mem->is_MergeMem()) {
Node* new_mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
set_req(Memory, new_mem);
if (mem->outcnt() == 0 && can_reshape) {
phase->is_IterGVN()->_worklist.push(mem);
}
return this;
}
bool optimizeLoadBarriers = phase->C->directive()->ZOptimizeLoadBarriersOption;
LoadBarrierNode* dominating_barrier = optimizeLoadBarriers ? has_dominating_barrier(NULL, !can_reshape, !phase->C->major_progress()) : NULL;
if (dominating_barrier != NULL && dominating_barrier->in(Oop) != in(Oop)) {
assert(in(Address) == dominating_barrier->in(Address), "");
set_req(Similar, dominating_barrier->proj_out(Oop));
return this;
}
bool eliminate = (optimizeLoadBarriers && !(val->is_Phi() || val->Opcode() == Op_LoadP || val->Opcode() == Op_GetAndSetP || val->is_DecodeN())) ||
(can_reshape && (dominating_barrier != NULL || !has_true_uses()));
if (eliminate) {
if (can_reshape) {
PhaseIterGVN* igvn = phase->is_IterGVN();
Node* out_ctrl = proj_out_or_null(Control);
Node* out_res = proj_out_or_null(Oop);
if (out_ctrl != NULL) {
igvn->replace_node(out_ctrl, ctrl);
}
// That transformation may cause the Similar edge on the load barrier to be invalid
fix_similar_in_uses(igvn);
if (out_res != NULL) {
if (dominating_barrier != NULL) {
igvn->replace_node(out_res, dominating_barrier->proj_out(Oop));
} else {
igvn->replace_node(out_res, val);
}
}
}
return new ConINode(TypeInt::ZERO);
}
// If the Similar edge is no longer a load barrier, clear it
Node* similar = in(Similar);
if (!similar->is_top() && !(similar->is_Proj() && similar->in(0)->is_LoadBarrier())) {
set_req(Similar, phase->C->top());
return this;
}
if (can_reshape) {
// If this barrier is linked through the Similar edge by a
// dominated barrier and both barriers have the same Oop field,
// the dominated barrier can go away, so push it for reprocessing.
// We also want to avoid a barrier to depend on another dominating
// barrier through its Similar edge that itself depend on another
// barrier through its Similar edge and rather have the first
// depend on the third.
PhaseIterGVN* igvn = phase->is_IterGVN();
Node* out_res = proj_out(Oop);
for (DUIterator_Fast imax, i = out_res->fast_outs(imax); i < imax; i++) {
Node* u = out_res->fast_out(i);
if (u->is_LoadBarrier() && u->in(Similar) == out_res &&
(u->in(Oop) == val || !u->in(Similar)->is_top())) {
igvn->_worklist.push(u);
}
}
push_dominated_barriers(igvn);
}
return NULL;
}
uint LoadBarrierNode::match_edge(uint idx) const {
ShouldNotReachHere();
return 0;
}
void LoadBarrierNode::fix_similar_in_uses(PhaseIterGVN* igvn) {
Node* out_res = proj_out_or_null(Oop);
if (out_res == NULL) {
return;
}
for (DUIterator_Fast imax, i = out_res->fast_outs(imax); i < imax; i++) {
Node* u = out_res->fast_out(i);
if (u->is_LoadBarrier() && u->in(Similar) == out_res) {
igvn->replace_input_of(u, Similar, igvn->C->top());
--i;
--imax;
}
}
}
bool LoadBarrierNode::has_true_uses() const {
Node* out_res = proj_out_or_null(Oop);
if (out_res == NULL) {
return false;
}
for (DUIterator_Fast imax, i = out_res->fast_outs(imax); i < imax; i++) {
Node* u = out_res->fast_out(i);
if (!u->is_LoadBarrier() || u->in(Similar) != out_res) {
return true;
}
}
return false;
}
// == Accesses ==
Node* ZBarrierSetC2::make_cas_loadbarrier(C2AtomicParseAccess& access) const {
assert(!UseCompressedOops, "Not allowed");
CompareAndSwapNode* cas = (CompareAndSwapNode*)access.raw_access();
PhaseGVN& gvn = access.gvn();
Compile* C = Compile::current();
GraphKit* kit = access.kit();
Node* in_ctrl = cas->in(MemNode::Control);
Node* in_mem = cas->in(MemNode::Memory);
Node* in_adr = cas->in(MemNode::Address);
Node* in_val = cas->in(MemNode::ValueIn);
Node* in_expected = cas->in(LoadStoreConditionalNode::ExpectedIn);
float likely = PROB_LIKELY(0.999);
const TypePtr *adr_type = gvn.type(in_adr)->isa_ptr();
Compile::AliasType* alias_type = C->alias_type(adr_type);
int alias_idx = C->get_alias_index(adr_type);
// Outer check - true: continue, false: load and check
Node* region = new RegionNode(3);
Node* phi = new PhiNode(region, TypeInt::BOOL);
Node* phi_mem = new PhiNode(region, Type::MEMORY, adr_type);
// Inner check - is the healed ref equal to the expected
Node* region2 = new RegionNode(3);
Node* phi2 = new PhiNode(region2, TypeInt::BOOL);
Node* phi_mem2 = new PhiNode(region2, Type::MEMORY, adr_type);
// CAS node returns 0 or 1
Node* cmp = gvn.transform(new CmpINode(cas, kit->intcon(0)));
Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::ne))->as_Bool();
IfNode* iff = gvn.transform(new IfNode(in_ctrl, bol, likely, COUNT_UNKNOWN))->as_If();
Node* then = gvn.transform(new IfTrueNode(iff));
Node* elsen = gvn.transform(new IfFalseNode(iff));
Node* scmemproj1 = gvn.transform(new SCMemProjNode(cas));
kit->set_memory(scmemproj1, alias_idx);
phi_mem->init_req(1, scmemproj1);
phi_mem2->init_req(2, scmemproj1);
// CAS fail - reload and heal oop
Node* reload = kit->make_load(elsen, in_adr, TypeOopPtr::BOTTOM, T_OBJECT, MemNode::unordered);
Node* barrier = gvn.transform(new LoadBarrierNode(C, elsen, scmemproj1, reload, in_adr, false, true, false));
Node* barrierctrl = gvn.transform(new ProjNode(barrier, LoadBarrierNode::Control));
Node* barrierdata = gvn.transform(new ProjNode(barrier, LoadBarrierNode::Oop));
// Check load
Node* tmpX = gvn.transform(new CastP2XNode(NULL, barrierdata));
Node* in_expX = gvn.transform(new CastP2XNode(NULL, in_expected));
Node* cmp2 = gvn.transform(new CmpXNode(tmpX, in_expX));
Node *bol2 = gvn.transform(new BoolNode(cmp2, BoolTest::ne))->as_Bool();
IfNode* iff2 = gvn.transform(new IfNode(barrierctrl, bol2, likely, COUNT_UNKNOWN))->as_If();
Node* then2 = gvn.transform(new IfTrueNode(iff2));
Node* elsen2 = gvn.transform(new IfFalseNode(iff2));
// redo CAS
Node* cas2 = gvn.transform(new CompareAndSwapPNode(elsen2, kit->memory(alias_idx), in_adr, in_val, in_expected, cas->order()));
Node* scmemproj2 = gvn.transform(new SCMemProjNode(cas2));
kit->set_control(elsen2);
kit->set_memory(scmemproj2, alias_idx);
// Merge inner flow - check if healed oop was equal too expected.
region2->set_req(1, kit->control());
region2->set_req(2, then2);
phi2->set_req(1, cas2);
phi2->set_req(2, kit->intcon(0));
phi_mem2->init_req(1, scmemproj2);
kit->set_memory(phi_mem2, alias_idx);
// Merge outer flow - then check if first CAS succeeded
region->set_req(1, then);
region->set_req(2, region2);
phi->set_req(1, kit->intcon(1));
phi->set_req(2, phi2);
phi_mem->init_req(2, phi_mem2);
kit->set_memory(phi_mem, alias_idx);
gvn.transform(region2);
gvn.transform(phi2);
gvn.transform(phi_mem2);
gvn.transform(region);
gvn.transform(phi);
gvn.transform(phi_mem);
kit->set_control(region);
kit->insert_mem_bar(Op_MemBarCPUOrder);
return phi;
}
Node* ZBarrierSetC2::make_cmpx_loadbarrier(C2AtomicParseAccess& access) const {
CompareAndExchangePNode* cmpx = (CompareAndExchangePNode*)access.raw_access();
GraphKit* kit = access.kit();
PhaseGVN& gvn = kit->gvn();
Compile* C = Compile::current();
Node* in_ctrl = cmpx->in(MemNode::Control);
Node* in_mem = cmpx->in(MemNode::Memory);
Node* in_adr = cmpx->in(MemNode::Address);
Node* in_val = cmpx->in(MemNode::ValueIn);
Node* in_expected = cmpx->in(LoadStoreConditionalNode::ExpectedIn);
float likely = PROB_LIKELY(0.999);
const TypePtr *adr_type = cmpx->get_ptr_type();
Compile::AliasType* alias_type = C->alias_type(adr_type);
int alias_idx = C->get_alias_index(adr_type);
// Outer check - true: continue, false: load and check
Node* region = new RegionNode(3);
Node* phi = new PhiNode(region, adr_type);
// Inner check - is the healed ref equal to the expected
Node* region2 = new RegionNode(3);
Node* phi2 = new PhiNode(region2, adr_type);
// Check if cmpx succeeded
Node* cmp = gvn.transform(new CmpPNode(cmpx, in_expected));
Node* bol = gvn.transform(new BoolNode(cmp, BoolTest::eq))->as_Bool();
IfNode* iff = gvn.transform(new IfNode(in_ctrl, bol, likely, COUNT_UNKNOWN))->as_If();
Node* then = gvn.transform(new IfTrueNode(iff));
Node* elsen = gvn.transform(new IfFalseNode(iff));
Node* scmemproj1 = gvn.transform(new SCMemProjNode(cmpx));
kit->set_memory(scmemproj1, alias_idx);
// CAS fail - reload and heal oop
Node* reload = kit->make_load(elsen, in_adr, TypeOopPtr::BOTTOM, T_OBJECT, MemNode::unordered);
Node* barrier = gvn.transform(new LoadBarrierNode(C, elsen, scmemproj1, reload, in_adr, false, true, false));
Node* barrierctrl = gvn.transform(new ProjNode(barrier, LoadBarrierNode::Control));
Node* barrierdata = gvn.transform(new ProjNode(barrier, LoadBarrierNode::Oop));
// Check load
Node* tmpX = gvn.transform(new CastP2XNode(NULL, barrierdata));
Node* in_expX = gvn.transform(new CastP2XNode(NULL, in_expected));
Node* cmp2 = gvn.transform(new CmpXNode(tmpX, in_expX));
Node *bol2 = gvn.transform(new BoolNode(cmp2, BoolTest::ne))->as_Bool();
IfNode* iff2 = gvn.transform(new IfNode(barrierctrl, bol2, likely, COUNT_UNKNOWN))->as_If();
Node* then2 = gvn.transform(new IfTrueNode(iff2));
Node* elsen2 = gvn.transform(new IfFalseNode(iff2));
// Redo CAS
Node* cmpx2 = gvn.transform(new CompareAndExchangePNode(elsen2, kit->memory(alias_idx), in_adr, in_val, in_expected, adr_type, cmpx->get_ptr_type(), cmpx->order()));
Node* scmemproj2 = gvn.transform(new SCMemProjNode(cmpx2));
kit->set_control(elsen2);
kit->set_memory(scmemproj2, alias_idx);
// Merge inner flow - check if healed oop was equal too expected.
region2->set_req(1, kit->control());
region2->set_req(2, then2);
phi2->set_req(1, cmpx2);
phi2->set_req(2, barrierdata);
// Merge outer flow - then check if first cas succeeded
region->set_req(1, then);
region->set_req(2, region2);
phi->set_req(1, cmpx);
phi->set_req(2, phi2);
gvn.transform(region2);
gvn.transform(phi2);
gvn.transform(region);
gvn.transform(phi);
kit->set_control(region);
kit->set_memory(in_mem, alias_idx);
kit->insert_mem_bar(Op_MemBarCPUOrder);
return phi;
}
Node* ZBarrierSetC2::load_barrier(GraphKit* kit, Node* val, Node* adr, bool weak, bool writeback, bool oop_reload_allowed) const {
PhaseGVN& gvn = kit->gvn();
Node* barrier = new LoadBarrierNode(Compile::current(), kit->control(), kit->memory(TypeRawPtr::BOTTOM), val, adr, weak, writeback, oop_reload_allowed);
Node* transformed_barrier = gvn.transform(barrier);
if (transformed_barrier->is_LoadBarrier()) {
if (barrier == transformed_barrier) {
kit->set_control(gvn.transform(new ProjNode(barrier, LoadBarrierNode::Control)));
}
Node* result = gvn.transform(new ProjNode(transformed_barrier, LoadBarrierNode::Oop));
return result;
} else {
return val;
}
}
static bool barrier_needed(C2Access& access) {
return ZBarrierSet::barrier_needed(access.decorators(), access.type());
}
Node* ZBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
Node* p = BarrierSetC2::load_at_resolved(access, val_type);
if (!barrier_needed(access)) {
return p;
}
bool weak = (access.decorators() & ON_WEAK_OOP_REF) != 0;
assert(access.is_parse_access(), "entry not supported at optimization time");
C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
GraphKit* kit = parse_access.kit();
PhaseGVN& gvn = kit->gvn();
Node* adr = access.addr().node();
Node* heap_base_oop = access.base();
bool unsafe = (access.decorators() & C2_UNSAFE_ACCESS) != 0;
if (unsafe) {
if (!ZVerifyLoadBarriers) {
p = load_barrier(kit, p, adr);
} else {
if (!TypePtr::NULL_PTR->higher_equal(gvn.type(heap_base_oop))) {
p = load_barrier(kit, p, adr);
} else {
IdealKit ideal(kit);
IdealVariable res(ideal);
#define __ ideal.
__ declarations_done();
__ set(res, p);
__ if_then(heap_base_oop, BoolTest::ne, kit->null(), PROB_UNLIKELY(0.999)); {
kit->sync_kit(ideal);
p = load_barrier(kit, p, adr);
__ set(res, p);
__ sync_kit(kit);
} __ end_if();
kit->final_sync(ideal);
p = __ value(res);
#undef __
}
}
return p;
} else {
return load_barrier(parse_access.kit(), p, access.addr().node(), weak, true, true);
}
}
Node* ZBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
Node* new_val, const Type* val_type) const {
Node* result = BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, val_type);
if (!barrier_needed(access)) {
return result;
}
access.set_needs_pinning(false);
return make_cmpx_loadbarrier(access);
}
Node* ZBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
Node* new_val, const Type* value_type) const {
Node* result = BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
if (!barrier_needed(access)) {
return result;
}
Node* load_store = access.raw_access();
bool weak_cas = (access.decorators() & C2_WEAK_CMPXCHG) != 0;
bool expected_is_null = (expected_val->get_ptr_type() == TypePtr::NULL_PTR);
if (!expected_is_null) {
if (weak_cas) {
access.set_needs_pinning(false);
load_store = make_cas_loadbarrier(access);
} else {
access.set_needs_pinning(false);
load_store = make_cas_loadbarrier(access);
}
}
return load_store;
}
Node* ZBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const {
Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, new_val, val_type);
if (!barrier_needed(access)) {
return result;
}
Node* load_store = access.raw_access();
Node* adr = access.addr().node();
assert(access.is_parse_access(), "entry not supported at optimization time");
C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
return load_barrier(parse_access.kit(), load_store, adr, false, false, false);
}
// == Macro Expansion ==
void ZBarrierSetC2::expand_loadbarrier_node(PhaseMacroExpand* phase, LoadBarrierNode* barrier) const {
Node* in_ctrl = barrier->in(LoadBarrierNode::Control);
Node* in_mem = barrier->in(LoadBarrierNode::Memory);
Node* in_val = barrier->in(LoadBarrierNode::Oop);
Node* in_adr = barrier->in(LoadBarrierNode::Address);
Node* out_ctrl = barrier->proj_out(LoadBarrierNode::Control);
Node* out_res = barrier->proj_out(LoadBarrierNode::Oop);
PhaseIterGVN &igvn = phase->igvn();
if (ZVerifyLoadBarriers) {
igvn.replace_node(out_res, in_val);
igvn.replace_node(out_ctrl, in_ctrl);
return;
}
if (barrier->can_be_eliminated()) {
// Clone and pin the load for this barrier below the dominating
// barrier: the load cannot be allowed to float above the
// dominating barrier
Node* load = in_val;
if (load->is_Load()) {
Node* new_load = load->clone();
Node* addp = new_load->in(MemNode::Address);
assert(addp->is_AddP() || addp->is_Phi() || addp->is_Load(), "bad address");
Node* cast = new CastPPNode(addp, igvn.type(addp), true);
Node* ctrl = NULL;
Node* similar = barrier->in(LoadBarrierNode::Similar);
if (similar->is_Phi()) {
// already expanded
ctrl = similar->in(0);
} else {
assert(similar->is_Proj() && similar->in(0)->is_LoadBarrier(), "unexpected graph shape");
ctrl = similar->in(0)->as_LoadBarrier()->proj_out(LoadBarrierNode::Control);
}
assert(ctrl != NULL, "bad control");
cast->set_req(0, ctrl);
igvn.transform(cast);
new_load->set_req(MemNode::Address, cast);
igvn.transform(new_load);
igvn.replace_node(out_res, new_load);
igvn.replace_node(out_ctrl, in_ctrl);
return;
}
// cannot eliminate
}
// There are two cases that require the basic loadbarrier
// 1) When the writeback of a healed oop must be avoided (swap)
// 2) When we must guarantee that no reload of is done (swap, cas, cmpx)
if (!barrier->is_writeback()) {
assert(!barrier->oop_reload_allowed(), "writeback barriers should be marked as requires oop");
}
if (!barrier->oop_reload_allowed()) {
expand_loadbarrier_basic(phase, barrier);
} else {
expand_loadbarrier_optimized(phase, barrier);
}
}
// Basic loadbarrier using conventional argument passing
void ZBarrierSetC2::expand_loadbarrier_basic(PhaseMacroExpand* phase, LoadBarrierNode *barrier) const {
PhaseIterGVN &igvn = phase->igvn();
Node* in_ctrl = barrier->in(LoadBarrierNode::Control);
Node* in_mem = barrier->in(LoadBarrierNode::Memory);
Node* in_val = barrier->in(LoadBarrierNode::Oop);
Node* in_adr = barrier->in(LoadBarrierNode::Address);
Node* out_ctrl = barrier->proj_out(LoadBarrierNode::Control);
Node* out_res = barrier->proj_out(LoadBarrierNode::Oop);
float unlikely = PROB_UNLIKELY(0.999);
const Type* in_val_maybe_null_t = igvn.type(in_val);
Node* jthread = igvn.transform(new ThreadLocalNode());
Node* adr = phase->basic_plus_adr(jthread, in_bytes(ZThreadLocalData::address_bad_mask_offset()));
Node* bad_mask = igvn.transform(LoadNode::make(igvn, in_ctrl, in_mem, adr, TypeRawPtr::BOTTOM, TypeX_X, TypeX_X->basic_type(), MemNode::unordered));
Node* cast = igvn.transform(new CastP2XNode(in_ctrl, in_val));
Node* obj_masked = igvn.transform(new AndXNode(cast, bad_mask));
Node* cmp = igvn.transform(new CmpXNode(obj_masked, igvn.zerocon(TypeX_X->basic_type())));
Node *bol = igvn.transform(new BoolNode(cmp, BoolTest::ne))->as_Bool();
IfNode* iff = igvn.transform(new IfNode(in_ctrl, bol, unlikely, COUNT_UNKNOWN))->as_If();
Node* then = igvn.transform(new IfTrueNode(iff));
Node* elsen = igvn.transform(new IfFalseNode(iff));
Node* result_region;
Node* result_val;
result_region = new RegionNode(3);
result_val = new PhiNode(result_region, TypeInstPtr::BOTTOM);
result_region->set_req(1, elsen);
Node* res = igvn.transform(new CastPPNode(in_val, in_val_maybe_null_t));
res->init_req(0, elsen);
result_val->set_req(1, res);
const TypeFunc *tf = load_barrier_Type();
Node* call;
if (barrier->is_weak()) {
call = new CallLeafNode(tf,
ZBarrierSetRuntime::load_barrier_on_weak_oop_field_preloaded_addr(),
"ZBarrierSetRuntime::load_barrier_on_weak_oop_field_preloaded",
TypeRawPtr::BOTTOM);
} else {
call = new CallLeafNode(tf,
ZBarrierSetRuntime::load_barrier_on_oop_field_preloaded_addr(),
"ZBarrierSetRuntime::load_barrier_on_oop_field_preloaded",
TypeRawPtr::BOTTOM);
}
call->init_req(TypeFunc::Control, then);
call->init_req(TypeFunc::I_O , phase->top());
call->init_req(TypeFunc::Memory , in_mem);
call->init_req(TypeFunc::FramePtr, phase->top());
call->init_req(TypeFunc::ReturnAdr, phase->top());
call->init_req(TypeFunc::Parms+0, in_val);
if (barrier->is_writeback()) {
call->init_req(TypeFunc::Parms+1, in_adr);
} else {
// When slow path is called with a null address, the healed oop will not be written back
call->init_req(TypeFunc::Parms+1, igvn.zerocon(T_OBJECT));
}
call = igvn.transform(call);
Node* ctrl = igvn.transform(new ProjNode(call, TypeFunc::Control));
res = igvn.transform(new ProjNode(call, TypeFunc::Parms));
res = igvn.transform(new CheckCastPPNode(ctrl, res, in_val_maybe_null_t));
result_region->set_req(2, ctrl);
result_val->set_req(2, res);
result_region = igvn.transform(result_region);
result_val = igvn.transform(result_val);
if (out_ctrl != NULL) { // Added if cond
igvn.replace_node(out_ctrl, result_region);
}
igvn.replace_node(out_res, result_val);
}
// Optimized, low spill, loadbarrier variant using stub specialized on register used
void ZBarrierSetC2::expand_loadbarrier_optimized(PhaseMacroExpand* phase, LoadBarrierNode *barrier) const {
PhaseIterGVN &igvn = phase->igvn();
#ifdef PRINT_NODE_TRAVERSALS
Node* preceding_barrier_node = barrier->in(LoadBarrierNode::Oop);
#endif
Node* in_ctrl = barrier->in(LoadBarrierNode::Control);
Node* in_mem = barrier->in(LoadBarrierNode::Memory);
Node* in_val = barrier->in(LoadBarrierNode::Oop);
Node* in_adr = barrier->in(LoadBarrierNode::Address);
Node* out_ctrl = barrier->proj_out(LoadBarrierNode::Control);
Node* out_res = barrier->proj_out(LoadBarrierNode::Oop);
assert(barrier->in(LoadBarrierNode::Oop) != NULL, "oop to loadbarrier node cannot be null");
#ifdef PRINT_NODE_TRAVERSALS
tty->print("\n\n\nBefore barrier optimization:\n");
traverse(barrier, out_ctrl, out_res, -1);
tty->print("\nBefore barrier optimization: preceding_barrier_node\n");
traverse(preceding_barrier_node, out_ctrl, out_res, -1);
#endif
float unlikely = PROB_UNLIKELY(0.999);
Node* jthread = igvn.transform(new ThreadLocalNode());
Node* adr = phase->basic_plus_adr(jthread, in_bytes(ZThreadLocalData::address_bad_mask_offset()));
Node* bad_mask = igvn.transform(LoadNode::make(igvn, in_ctrl, in_mem, adr,
TypeRawPtr::BOTTOM, TypeX_X, TypeX_X->basic_type(),
MemNode::unordered));
Node* cast = igvn.transform(new CastP2XNode(in_ctrl, in_val));
Node* obj_masked = igvn.transform(new AndXNode(cast, bad_mask));
Node* cmp = igvn.transform(new CmpXNode(obj_masked, igvn.zerocon(TypeX_X->basic_type())));
Node *bol = igvn.transform(new BoolNode(cmp, BoolTest::ne))->as_Bool();
IfNode* iff = igvn.transform(new IfNode(in_ctrl, bol, unlikely, COUNT_UNKNOWN))->as_If();
Node* then = igvn.transform(new IfTrueNode(iff));
Node* elsen = igvn.transform(new IfFalseNode(iff));
Node* slow_path_surrogate;
if (!barrier->is_weak()) {
slow_path_surrogate = igvn.transform(new LoadBarrierSlowRegNode(then, in_mem, in_adr, in_val->adr_type(),
(const TypePtr*) in_val->bottom_type(), MemNode::unordered));
} else {
slow_path_surrogate = igvn.transform(new LoadBarrierWeakSlowRegNode(then, in_mem, in_adr, in_val->adr_type(),
(const TypePtr*) in_val->bottom_type(), MemNode::unordered));
}
Node *new_loadp;
new_loadp = slow_path_surrogate;
// Create the final region/phi pair to converge cntl/data paths to downstream code
Node* result_region = igvn.transform(new RegionNode(3));
result_region->set_req(1, then);
result_region->set_req(2, elsen);
Node* result_phi = igvn.transform(new PhiNode(result_region, TypeInstPtr::BOTTOM));
result_phi->set_req(1, new_loadp);
result_phi->set_req(2, barrier->in(LoadBarrierNode::Oop));
// Finally, connect the original outputs to the barrier region and phi to complete the expansion/substitution
// igvn.replace_node(out_ctrl, result_region);
if (out_ctrl != NULL) { // added if cond
igvn.replace_node(out_ctrl, result_region);
}
igvn.replace_node(out_res, result_phi);
assert(barrier->outcnt() == 0,"LoadBarrier macro node has non-null outputs after expansion!");
#ifdef PRINT_NODE_TRAVERSALS
tty->print("\nAfter barrier optimization: old out_ctrl\n");
traverse(out_ctrl, out_ctrl, out_res, -1);
tty->print("\nAfter barrier optimization: old out_res\n");
traverse(out_res, out_ctrl, out_res, -1);
tty->print("\nAfter barrier optimization: old barrier\n");
traverse(barrier, out_ctrl, out_res, -1);
tty->print("\nAfter barrier optimization: preceding_barrier_node\n");
traverse(preceding_barrier_node, result_region, result_phi, -1);
#endif
assert(is_gc_barrier_node(result_phi), "sanity");
assert(step_over_gc_barrier(result_phi) == in_val, "sanity");
}
bool ZBarrierSetC2::expand_barriers(Compile* C, PhaseIterGVN& igvn) const {
ZBarrierSetC2State* s = state();
if (s->load_barrier_count() > 0) {
PhaseMacroExpand macro(igvn);
#ifdef ASSERT
verify_gc_barriers(false);
#endif
int skipped = 0;
while (s->load_barrier_count() > skipped) {
int load_barrier_count = s->load_barrier_count();
LoadBarrierNode * n = s->load_barrier_node(load_barrier_count-1-skipped);
if (igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())) {
// Node is unreachable, so don't try to expand it
s->remove_load_barrier_node(n);
continue;
}
if (!n->can_be_eliminated()) {
skipped++;
continue;
}
expand_loadbarrier_node(¯o, n);
assert(s->load_barrier_count() < load_barrier_count, "must have deleted a node from load barrier list");
if (C->failing()) {
return true;
}
}
while (s->load_barrier_count() > 0) {
int load_barrier_count = s->load_barrier_count();
LoadBarrierNode* n = s->load_barrier_node(load_barrier_count - 1);
assert(!(igvn.type(n) == Type::TOP || (n->in(0) != NULL && n->in(0)->is_top())), "should have been processed already");
assert(!n->can_be_eliminated(), "should have been processed already");
expand_loadbarrier_node(¯o, n);
assert(s->load_barrier_count() < load_barrier_count, "must have deleted a node from load barrier list");
if (C->failing()) {
return true;
}
}
igvn.set_delay_transform(false);
igvn.optimize();
if (C->failing()) {
return true;
}
}
return false;
}
// == Loop optimization ==
static bool replace_with_dominating_barrier(PhaseIdealLoop* phase, LoadBarrierNode* lb, bool last_round) {
PhaseIterGVN &igvn = phase->igvn();
Compile* C = Compile::current();
LoadBarrierNode* lb2 = lb->has_dominating_barrier(phase, false, last_round);
if (lb2 == NULL) {
return false;
}
if (lb->in(LoadBarrierNode::Oop) != lb2->in(LoadBarrierNode::Oop)) {
assert(lb->in(LoadBarrierNode::Address) == lb2->in(LoadBarrierNode::Address), "Invalid address");
igvn.replace_input_of(lb, LoadBarrierNode::Similar, lb2->proj_out(LoadBarrierNode::Oop));
C->set_major_progress();
return false;
}
// That transformation may cause the Similar edge on dominated load barriers to be invalid
lb->fix_similar_in_uses(&igvn);
Node* val = lb->proj_out(LoadBarrierNode::Oop);
assert(lb2->has_true_uses(), "Invalid uses");
assert(lb2->in(LoadBarrierNode::Oop) == lb->in(LoadBarrierNode::Oop), "Invalid oop");
phase->lazy_update(lb, lb->in(LoadBarrierNode::Control));
phase->lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
igvn.replace_node(val, lb2->proj_out(LoadBarrierNode::Oop));
return true;
}
static Node* find_dominating_memory(PhaseIdealLoop* phase, Node* mem, Node* dom, int i) {
assert(dom->is_Region() || i == -1, "");
Node* m = mem;
while(phase->is_dominator(dom, phase->has_ctrl(m) ? phase->get_ctrl(m) : m->in(0))) {
if (m->is_Mem()) {
assert(m->as_Mem()->adr_type() == TypeRawPtr::BOTTOM, "");
m = m->in(MemNode::Memory);
} else if (m->is_MergeMem()) {
m = m->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
} else if (m->is_Phi()) {
if (m->in(0) == dom && i != -1) {
m = m->in(i);
break;
} else {
m = m->in(LoopNode::EntryControl);
}
} else if (m->is_Proj()) {
m = m->in(0);
} else if (m->is_SafePoint() || m->is_MemBar()) {
m = m->in(TypeFunc::Memory);
} else {
#ifdef ASSERT
m->dump();
#endif
ShouldNotReachHere();
}
}
return m;
}
static LoadBarrierNode* clone_load_barrier(PhaseIdealLoop* phase, LoadBarrierNode* lb, Node* ctl, Node* mem, Node* oop_in) {
PhaseIterGVN &igvn = phase->igvn();
Compile* C = Compile::current();
Node* the_clone = lb->clone();
the_clone->set_req(LoadBarrierNode::Control, ctl);
the_clone->set_req(LoadBarrierNode::Memory, mem);
if (oop_in != NULL) {
the_clone->set_req(LoadBarrierNode::Oop, oop_in);
}
LoadBarrierNode* new_lb = the_clone->as_LoadBarrier();
igvn.register_new_node_with_optimizer(new_lb);
IdealLoopTree *loop = phase->get_loop(new_lb->in(0));
phase->set_ctrl(new_lb, new_lb->in(0));
phase->set_loop(new_lb, loop);
phase->set_idom(new_lb, new_lb->in(0), phase->dom_depth(new_lb->in(0))+1);
if (!loop->_child) {
loop->_body.push(new_lb);
}
Node* proj_ctl = new ProjNode(new_lb, LoadBarrierNode::Control);
igvn.register_new_node_with_optimizer(proj_ctl);
phase->set_ctrl(proj_ctl, proj_ctl->in(0));
phase->set_loop(proj_ctl, loop);
phase->set_idom(proj_ctl, new_lb, phase->dom_depth(new_lb)+1);
if (!loop->_child) {
loop->_body.push(proj_ctl);
}
Node* proj_oop = new ProjNode(new_lb, LoadBarrierNode::Oop);
phase->register_new_node(proj_oop, new_lb);
if (!new_lb->in(LoadBarrierNode::Similar)->is_top()) {
LoadBarrierNode* similar = new_lb->in(LoadBarrierNode::Similar)->in(0)->as_LoadBarrier();
if (!phase->is_dominator(similar, ctl)) {
igvn.replace_input_of(new_lb, LoadBarrierNode::Similar, C->top());
}
}
return new_lb;
}
static void replace_barrier(PhaseIdealLoop* phase, LoadBarrierNode* lb, Node* new_val) {
PhaseIterGVN &igvn = phase->igvn();
Node* val = lb->proj_out(LoadBarrierNode::Oop);
igvn.replace_node(val, new_val);
phase->lazy_update(lb, lb->in(LoadBarrierNode::Control));
phase->lazy_replace(lb->proj_out(LoadBarrierNode::Control), lb->in(LoadBarrierNode::Control));
}
static bool split_barrier_thru_phi(PhaseIdealLoop* phase, LoadBarrierNode* lb) {
PhaseIterGVN &igvn = phase->igvn();
Compile* C = Compile::current();
if (lb->in(LoadBarrierNode::Oop)->is_Phi()) {
Node* oop_phi = lb->in(LoadBarrierNode::Oop);
if ((oop_phi->req() != 3) || (oop_phi->in(2) == oop_phi)) {
// Ignore phis with only one input
return false;
}
if (phase->is_dominator(phase->get_ctrl(lb->in(LoadBarrierNode::Address)),
oop_phi->in(0)) && phase->get_ctrl(lb->in(LoadBarrierNode::Address)) != oop_phi->in(0)) {
// That transformation may cause the Similar edge on dominated load barriers to be invalid
lb->fix_similar_in_uses(&igvn);
RegionNode* region = oop_phi->in(0)->as_Region();
int backedge = LoopNode::LoopBackControl;
if (region->is_Loop() && region->in(backedge)->is_Proj() && region->in(backedge)->in(0)->is_If()) {
Node* c = region->in(backedge)->in(0)->in(0);
assert(c->unique_ctrl_out() == region->in(backedge)->in(0), "");
Node* oop = lb->in(LoadBarrierNode::Oop)->in(backedge);
Node* oop_c = phase->has_ctrl(oop) ? phase->get_ctrl(oop) : oop;
if (!phase->is_dominator(oop_c, c)) {
return false;
}
}
// If the node on the backedge above the phi is the node itself - we have a self loop.
// Don't clone - this will be folded later.
if (oop_phi->in(LoopNode::LoopBackControl) == lb->proj_out(LoadBarrierNode::Oop)) {
return false;
}
bool is_strip_mined = region->is_CountedLoop() && region->as_CountedLoop()->is_strip_mined();
Node *phi = oop_phi->clone();
for (uint i = 1; i < region->req(); i++) {
Node* ctrl = region->in(i);
if (ctrl != C->top()) {
assert(!phase->is_dominator(ctrl, region) || region->is_Loop(), "");
Node* mem = lb->in(LoadBarrierNode::Memory);
Node* m = find_dominating_memory(phase, mem, region, i);
if (region->is_Loop() && i == LoopNode::LoopBackControl && ctrl->is_Proj() && ctrl->in(0)->is_If()) {
ctrl = ctrl->in(0)->in(0);
} else if (region->is_Loop() && is_strip_mined) {
// If this is a strip mined loop, control must move above OuterStripMinedLoop
assert(i == LoopNode::EntryControl, "check");
assert(ctrl->is_OuterStripMinedLoop(), "sanity");
ctrl = ctrl->as_OuterStripMinedLoop()->in(LoopNode::EntryControl);
}
LoadBarrierNode* new_lb = clone_load_barrier(phase, lb, ctrl, m, lb->in(LoadBarrierNode::Oop)->in(i));
Node* out_ctrl = new_lb->proj_out(LoadBarrierNode::Control);
if (is_strip_mined && (i == LoopNode::EntryControl)) {
assert(region->in(i)->is_OuterStripMinedLoop(), "");
igvn.replace_input_of(region->in(i), i, out_ctrl);
phase->set_idom(region->in(i), out_ctrl, phase->dom_depth(out_ctrl));
} else if (ctrl == region->in(i)) {
igvn.replace_input_of(region, i, out_ctrl);
// Only update the idom if is the loop entry we are updating
// - A loop backedge doesn't change the idom
if (region->is_Loop() && i == LoopNode::EntryControl) {
phase->set_idom(region, out_ctrl, phase->dom_depth(out_ctrl));
}
} else {
Node* iff = region->in(i)->in(0);
igvn.replace_input_of(iff, 0, out_ctrl);
phase->set_idom(iff, out_ctrl, phase->dom_depth(out_ctrl)+1);
}
phi->set_req(i, new_lb->proj_out(LoadBarrierNode::Oop));
}
}
phase->register_new_node(phi, region);
replace_barrier(phase, lb, phi);
if (region->is_Loop()) {
// Load barrier moved to the back edge of the Loop may now
// have a safepoint on the path to the barrier on the Similar
// edge
igvn.replace_input_of(phi->in(LoopNode::LoopBackControl)->in(0), LoadBarrierNode::Similar, C->top());
Node* head = region->in(LoopNode::EntryControl);
phase->set_idom(region, head, phase->dom_depth(head)+1);
phase->recompute_dom_depth();
if (head->is_CountedLoop() && head->as_CountedLoop()->is_main_loop()) {
head->as_CountedLoop()->set_normal_loop();
}
}
return true;
}
}
return false;
}
static bool move_out_of_loop(PhaseIdealLoop* phase, LoadBarrierNode* lb) {
PhaseIterGVN &igvn = phase->igvn();
IdealLoopTree *lb_loop = phase->get_loop(lb->in(0));
if (lb_loop != phase->ltree_root() && !lb_loop->_irreducible) {
Node* oop_ctrl = phase->get_ctrl(lb->in(LoadBarrierNode::Oop));
IdealLoopTree *oop_loop = phase->get_loop(oop_ctrl);
IdealLoopTree* adr_loop = phase->get_loop(phase->get_ctrl(lb->in(LoadBarrierNode::Address)));
if (!lb_loop->is_member(oop_loop) && !lb_loop->is_member(adr_loop)) {
// That transformation may cause the Similar edge on dominated load barriers to be invalid
lb->fix_similar_in_uses(&igvn);
Node* head = lb_loop->_head;
assert(head->is_Loop(), "");
if (phase->is_dominator(head, oop_ctrl)) {
assert(oop_ctrl->Opcode() == Op_CProj && oop_ctrl->in(0)->Opcode() == Op_NeverBranch, "");
assert(lb_loop->is_member(phase->get_loop(oop_ctrl->in(0)->in(0))), "");
return false;
}
if (head->is_CountedLoop()) {
CountedLoopNode* cloop = head->as_CountedLoop();
if (cloop->is_main_loop()) {
cloop->set_normal_loop();
}
// When we are moving barrier out of a counted loop,
// make sure we move it all the way out of the strip mined outer loop.
if (cloop->is_strip_mined()) {
head = cloop->outer_loop();
}
}
Node* mem = lb->in(LoadBarrierNode::Memory);
Node* m = find_dominating_memory(phase, mem, head, -1);
LoadBarrierNode* new_lb = clone_load_barrier(phase, lb, head->in(LoopNode::EntryControl), m, NULL);
assert(phase->idom(head) == head->in(LoopNode::EntryControl), "");
Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
igvn.replace_input_of(head, LoopNode::EntryControl, proj_ctl);
phase->set_idom(head, proj_ctl, phase->dom_depth(proj_ctl) + 1);
replace_barrier(phase, lb, new_lb->proj_out(LoadBarrierNode::Oop));
phase->recompute_dom_depth();
return true;
}
}
return false;
}
static bool common_barriers(PhaseIdealLoop* phase, LoadBarrierNode* lb) {
PhaseIterGVN &igvn = phase->igvn();
Node* in_val = lb->in(LoadBarrierNode::Oop);
for (DUIterator_Fast imax, i = in_val->fast_outs(imax); i < imax; i++) {
Node* u = in_val->fast_out(i);
if (u != lb && u->is_LoadBarrier() && u->as_LoadBarrier()->has_true_uses()) {
Node* this_ctrl = lb->in(LoadBarrierNode::Control);
Node* other_ctrl = u->in(LoadBarrierNode::Control);
Node* lca = phase->dom_lca(this_ctrl, other_ctrl);
bool ok = true;
Node* proj1 = NULL;
Node* proj2 = NULL;
while (this_ctrl != lca && ok) {
if (this_ctrl->in(0) != NULL &&
this_ctrl->in(0)->is_MultiBranch()) {
if (this_ctrl->in(0)->in(0) == lca) {
assert(proj1 == NULL, "");
assert(this_ctrl->is_Proj(), "");
proj1 = this_ctrl;
} else if (!(this_ctrl->in(0)->is_If() && this_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
ok = false;
}
}
this_ctrl = phase->idom(this_ctrl);
}
while (other_ctrl != lca && ok) {
if (other_ctrl->in(0) != NULL &&
other_ctrl->in(0)->is_MultiBranch()) {
if (other_ctrl->in(0)->in(0) == lca) {
assert(other_ctrl->is_Proj(), "");
assert(proj2 == NULL, "");
proj2 = other_ctrl;
} else if (!(other_ctrl->in(0)->is_If() && other_ctrl->as_Proj()->is_uncommon_trap_if_pattern(Deoptimization::Reason_none))) {
ok = false;
}
}
other_ctrl = phase->idom(other_ctrl);
}
assert(proj1 == NULL || proj2 == NULL || proj1->in(0) == proj2->in(0), "");
if (ok && proj1 && proj2 && proj1 != proj2 && proj1->in(0)->is_If()) {
// That transformation may cause the Similar edge on dominated load barriers to be invalid
lb->fix_similar_in_uses(&igvn);
u->as_LoadBarrier()->fix_similar_in_uses(&igvn);
Node* split = lca->unique_ctrl_out();
assert(split->in(0) == lca, "");
Node* mem = lb->in(LoadBarrierNode::Memory);
Node* m = find_dominating_memory(phase, mem, split, -1);
LoadBarrierNode* new_lb = clone_load_barrier(phase, lb, lca, m, NULL);
Node* proj_ctl = new_lb->proj_out(LoadBarrierNode::Control);
igvn.replace_input_of(split, 0, new_lb->proj_out(LoadBarrierNode::Control));
phase->set_idom(split, proj_ctl, phase->dom_depth(proj_ctl)+1);
Node* proj_oop = new_lb->proj_out(LoadBarrierNode::Oop);
replace_barrier(phase, lb, proj_oop);
replace_barrier(phase, u->as_LoadBarrier(), proj_oop);
phase->recompute_dom_depth();
return true;
}
}
}
return false;
}
void ZBarrierSetC2::loop_optimize_gc_barrier(PhaseIdealLoop* phase, Node* node, bool last_round) {
if (!Compile::current()->directive()->ZOptimizeLoadBarriersOption) {
return;
}
if (!node->is_LoadBarrier()) {
return;
}
if (!node->as_LoadBarrier()->has_true_uses()) {
return;
}
if (replace_with_dominating_barrier(phase, node->as_LoadBarrier(), last_round)) {
return;
}
if (split_barrier_thru_phi(phase, node->as_LoadBarrier())) {
return;
}
if (move_out_of_loop(phase, node->as_LoadBarrier())) {
return;
}
if (common_barriers(phase, node->as_LoadBarrier())) {
return;
}
}
Node* ZBarrierSetC2::step_over_gc_barrier(Node* c) const {
Node* node = c;
// 1. This step follows potential oop projections of a load barrier before expansion
if (node->is_Proj()) {
node = node->in(0);
}
// 2. This step checks for unexpanded load barriers
if (node->is_LoadBarrier()) {
return node->in(LoadBarrierNode::Oop);
}
// 3. This step checks for the phi corresponding to an optimized load barrier expansion
if (node->is_Phi()) {
PhiNode* phi = node->as_Phi();
Node* n = phi->in(1);
if (n != NULL && (n->is_LoadBarrierSlowReg() || n->is_LoadBarrierWeakSlowReg())) {
assert(c == node, "projections from step 1 should only be seen before macro expansion");
return phi->in(2);
}
}
return c;
}
bool ZBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type, bool is_clone, ArrayCopyPhase phase) const {
return type == T_OBJECT || type == T_ARRAY;
}
bool ZBarrierSetC2::final_graph_reshaping(Compile* compile, Node* n, uint opcode) const {
if (opcode != Op_LoadBarrierSlowReg &&
opcode != Op_LoadBarrierWeakSlowReg) {
return false;
}
#ifdef ASSERT
if (VerifyOptoOopOffsets) {
MemNode* mem = n->as_Mem();
// Check to see if address types have grounded out somehow.
const TypeInstPtr* tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
ciInstanceKlass* k = tp->klass()->as_instance_klass();
bool oop_offset_is_sane = k->contains_field_offset(tp->offset());
assert(!tp || oop_offset_is_sane, "");
}
#endif
return true;
}
bool ZBarrierSetC2::matcher_find_shared_visit(Matcher* matcher, Matcher::MStack& mstack, Node* n, uint opcode, bool& mem_op, int& mem_addr_idx) const {
if (opcode == Op_CallLeaf &&
(n->as_Call()->entry_point() == ZBarrierSetRuntime::load_barrier_on_oop_field_preloaded_addr() ||
n->as_Call()->entry_point() == ZBarrierSetRuntime::load_barrier_on_weak_oop_field_preloaded_addr())) {
mem_op = true;
mem_addr_idx = TypeFunc::Parms + 1;
return true;
}
return false;
}
// == Verification ==
#ifdef ASSERT
static bool look_for_barrier(Node* n, bool post_parse, VectorSet& visited) {
if (visited.test_set(n->_idx)) {
return true;
}
for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
Node* u = n->fast_out(i);
if (u->is_LoadBarrier()) {
} else if ((u->is_Phi() || u->is_CMove()) && !post_parse) {
if (!look_for_barrier(u, post_parse, visited)) {
return false;
}
} else if (u->Opcode() == Op_EncodeP || u->Opcode() == Op_DecodeN) {
if (!look_for_barrier(u, post_parse, visited)) {
return false;
}
} else if (u->Opcode() != Op_SCMemProj) {
tty->print("bad use"); u->dump();
return false;
}
}
return true;
}
void ZBarrierSetC2::verify_gc_barriers(Compile* compile, CompilePhase phase) const {
if (phase == BarrierSetC2::BeforeCodeGen) return;
bool post_parse = phase == BarrierSetC2::BeforeOptimize;
verify_gc_barriers(post_parse);
}
void ZBarrierSetC2::verify_gc_barriers(bool post_parse) const {
ZBarrierSetC2State* s = state();
Compile* C = Compile::current();
ResourceMark rm;
VectorSet visited(Thread::current()->resource_area());
for (int i = 0; i < s->load_barrier_count(); i++) {
LoadBarrierNode* n = s->load_barrier_node(i);
// The dominating barrier on the same address if it exists and
// this barrier must not be applied on the value from the same
// load otherwise the value is not reloaded before it's used the
// second time.
assert(n->in(LoadBarrierNode::Similar)->is_top() ||
(n->in(LoadBarrierNode::Similar)->in(0)->is_LoadBarrier() &&
n->in(LoadBarrierNode::Similar)->in(0)->in(LoadBarrierNode::Address) == n->in(LoadBarrierNode::Address) &&
n->in(LoadBarrierNode::Similar)->in(0)->in(LoadBarrierNode::Oop) != n->in(LoadBarrierNode::Oop)),
"broken similar edge");
assert(post_parse || n->as_LoadBarrier()->has_true_uses(),
"found unneeded load barrier");
// Several load barrier nodes chained through their Similar edge
// break the code that remove the barriers in final graph reshape.
assert(n->in(LoadBarrierNode::Similar)->is_top() ||
(n->in(LoadBarrierNode::Similar)->in(0)->is_LoadBarrier() &&
n->in(LoadBarrierNode::Similar)->in(0)->in(LoadBarrierNode::Similar)->is_top()),
"chain of Similar load barriers");
if (!n->in(LoadBarrierNode::Similar)->is_top()) {
ResourceMark rm;
Unique_Node_List wq;
Node* other = n->in(LoadBarrierNode::Similar)->in(0);
wq.push(n);
bool ok = true;
bool dom_found = false;
for (uint next = 0; next < wq.size(); ++next) {
Node *n = wq.at(next);
assert(n->is_CFG(), "");
assert(!n->is_SafePoint(), "");
if (n == other) {
continue;
}
if (n->is_Region()) {
for (uint i = 1; i < n->req(); i++) {
Node* m = n->in(i);
if (m != NULL) {
wq.push(m);
}
}
} else {
Node* m = n->in(0);
if (m != NULL) {
wq.push(m);
}
}
}
}
if (ZVerifyLoadBarriers) {
if ((n->is_Load() || n->is_LoadStore()) && n->bottom_type()->make_oopptr() != NULL) {
visited.Clear();
bool found = look_for_barrier(n, post_parse, visited);
if (!found) {
n->dump(1);
n->dump(-3);
stringStream ss;
C->method()->print_short_name(&ss);
tty->print_cr("-%s-", ss.as_string());
assert(found, "");
}
}
}
}
}
#endif
bool ZBarrierSetC2::escape_add_to_con_graph(ConnectionGraph* conn_graph, PhaseGVN* gvn, Unique_Node_List* delayed_worklist, Node* n, uint opcode) const {
switch (opcode) {
case Op_LoadBarrierSlowReg:
case Op_LoadBarrierWeakSlowReg:
conn_graph->add_objload_to_connection_graph(n, delayed_worklist);
return true;
case Op_Proj:
if (n->as_Proj()->_con != LoadBarrierNode::Oop || !n->in(0)->is_LoadBarrier()) {
return false;
}
conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0)->in(LoadBarrierNode::Oop), delayed_worklist);
return true;
}
return false;
}
bool ZBarrierSetC2::escape_add_final_edges(ConnectionGraph* conn_graph, PhaseGVN* gvn, Node* n, uint opcode) const {
switch (opcode) {
case Op_LoadBarrierSlowReg:
case Op_LoadBarrierWeakSlowReg:
if (gvn->type(n)->make_ptr() == NULL) {
return false;
}
conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(MemNode::Address), NULL);
return true;
case Op_Proj:
if (n->as_Proj()->_con != LoadBarrierNode::Oop || !n->in(0)->is_LoadBarrier()) {
return false;
}
conn_graph->add_local_var_and_edge(n, PointsToNode::NoEscape, n->in(0)->in(LoadBarrierNode::Oop), NULL);
return true;
}
return false;
}