1 /*
2 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "compiler/compileLog.hpp"
28 #include "gc/shared/barrierSet.hpp"
29 #include "gc/shared/c2/barrierSetC2.hpp"
30 #include "gc/shared/tlab_globals.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/objArrayKlass.hpp"
34 #include "opto/addnode.hpp"
35 #include "opto/arraycopynode.hpp"
36 #include "opto/cfgnode.hpp"
37 #include "opto/regalloc.hpp"
38 #include "opto/compile.hpp"
39 #include "opto/connode.hpp"
40 #include "opto/convertnode.hpp"
41 #include "opto/loopnode.hpp"
42 #include "opto/machnode.hpp"
43 #include "opto/matcher.hpp"
44 #include "opto/memnode.hpp"
45 #include "opto/mulnode.hpp"
46 #include "opto/narrowptrnode.hpp"
47 #include "opto/phaseX.hpp"
48 #include "opto/regmask.hpp"
49 #include "opto/rootnode.hpp"
50 #include "opto/vectornode.hpp"
51 #include "utilities/align.hpp"
52 #include "utilities/copy.hpp"
53 #include "utilities/macros.hpp"
54 #include "utilities/powerOfTwo.hpp"
55 #include "utilities/vmError.hpp"
56
57 // Portions of code courtesy of Clifford Click
58
59 // Optimization - Graph Style
60
61 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st);
62
63 //=============================================================================
64 uint MemNode::size_of() const { return sizeof(*this); }
65
66 const TypePtr *MemNode::adr_type() const {
67 Node* adr = in(Address);
68 if (adr == nullptr) return nullptr; // node is dead
69 const TypePtr* cross_check = nullptr;
70 DEBUG_ONLY(cross_check = _adr_type);
71 return calculate_adr_type(adr->bottom_type(), cross_check);
72 }
73
74 bool MemNode::check_if_adr_maybe_raw(Node* adr) {
75 if (adr != nullptr) {
76 if (adr->bottom_type()->base() == Type::RawPtr || adr->bottom_type()->base() == Type::AnyPtr) {
77 return true;
78 }
79 }
80 return false;
81 }
82
83 #ifndef PRODUCT
84 void MemNode::dump_spec(outputStream *st) const {
85 if (in(Address) == nullptr) return; // node is dead
86 #ifndef ASSERT
87 // fake the missing field
88 const TypePtr* _adr_type = nullptr;
89 if (in(Address) != nullptr)
90 _adr_type = in(Address)->bottom_type()->isa_ptr();
91 #endif
92 dump_adr_type(this, _adr_type, st);
93
94 Compile* C = Compile::current();
95 if (C->alias_type(_adr_type)->is_volatile()) {
96 st->print(" Volatile!");
97 }
98 if (_unaligned_access) {
99 st->print(" unaligned");
100 }
101 if (_mismatched_access) {
102 st->print(" mismatched");
103 }
104 if (_unsafe_access) {
105 st->print(" unsafe");
106 }
107 }
108
109 void MemNode::dump_adr_type(const Node* mem, const TypePtr* adr_type, outputStream *st) {
110 st->print(" @");
111 if (adr_type == nullptr) {
112 st->print("null");
113 } else {
114 adr_type->dump_on(st);
115 Compile* C = Compile::current();
116 Compile::AliasType* atp = nullptr;
117 if (C->have_alias_type(adr_type)) atp = C->alias_type(adr_type);
118 if (atp == nullptr)
119 st->print(", idx=?\?;");
120 else if (atp->index() == Compile::AliasIdxBot)
121 st->print(", idx=Bot;");
122 else if (atp->index() == Compile::AliasIdxTop)
123 st->print(", idx=Top;");
124 else if (atp->index() == Compile::AliasIdxRaw)
125 st->print(", idx=Raw;");
126 else {
127 ciField* field = atp->field();
128 if (field) {
129 st->print(", name=");
130 field->print_name_on(st);
131 }
132 st->print(", idx=%d;", atp->index());
133 }
134 }
135 }
136
137 extern void print_alias_types();
138
139 #endif
140
141 Node *MemNode::optimize_simple_memory_chain(Node *mchain, const TypeOopPtr *t_oop, Node *load, PhaseGVN *phase) {
142 assert((t_oop != nullptr), "sanity");
143 bool is_instance = t_oop->is_known_instance_field();
144 bool is_boxed_value_load = t_oop->is_ptr_to_boxed_value() &&
145 (load != nullptr) && load->is_Load() &&
146 (phase->is_IterGVN() != nullptr);
147 if (!(is_instance || is_boxed_value_load))
148 return mchain; // don't try to optimize non-instance types
149 uint instance_id = t_oop->instance_id();
150 Node *start_mem = phase->C->start()->proj_out_or_null(TypeFunc::Memory);
151 Node *prev = nullptr;
152 Node *result = mchain;
153 while (prev != result) {
154 prev = result;
155 if (result == start_mem)
156 break; // hit one of our sentinels
157 // skip over a call which does not affect this memory slice
158 if (result->is_Proj() && result->as_Proj()->_con == TypeFunc::Memory) {
159 Node *proj_in = result->in(0);
160 if (proj_in->is_Allocate() && proj_in->_idx == instance_id) {
161 break; // hit one of our sentinels
162 } else if (proj_in->is_Call()) {
163 // ArrayCopyNodes processed here as well
164 CallNode *call = proj_in->as_Call();
165 if (!call->may_modify(t_oop, phase)) { // returns false for instances
166 result = call->in(TypeFunc::Memory);
167 }
168 } else if (proj_in->is_Initialize()) {
169 AllocateNode* alloc = proj_in->as_Initialize()->allocation();
170 // Stop if this is the initialization for the object instance which
171 // contains this memory slice, otherwise skip over it.
172 if ((alloc == nullptr) || (alloc->_idx == instance_id)) {
173 break;
174 }
175 if (is_instance) {
176 result = proj_in->in(TypeFunc::Memory);
177 } else if (is_boxed_value_load) {
178 Node* klass = alloc->in(AllocateNode::KlassNode);
179 const TypeKlassPtr* tklass = phase->type(klass)->is_klassptr();
180 if (tklass->klass_is_exact() && !tklass->exact_klass()->equals(t_oop->is_instptr()->exact_klass())) {
181 result = proj_in->in(TypeFunc::Memory); // not related allocation
182 }
183 }
184 } else if (proj_in->is_MemBar()) {
185 ArrayCopyNode* ac = nullptr;
186 if (ArrayCopyNode::may_modify(t_oop, proj_in->as_MemBar(), phase, ac)) {
187 break;
188 }
189 result = proj_in->in(TypeFunc::Memory);
190 } else if (proj_in->is_top()) {
191 break; // dead code
192 } else {
193 assert(false, "unexpected projection");
194 }
195 } else if (result->is_ClearArray()) {
196 if (!is_instance || !ClearArrayNode::step_through(&result, instance_id, phase)) {
197 // Can not bypass initialization of the instance
198 // we are looking for.
199 break;
200 }
201 // Otherwise skip it (the call updated 'result' value).
202 } else if (result->is_MergeMem()) {
203 result = step_through_mergemem(phase, result->as_MergeMem(), t_oop, nullptr, tty);
204 }
205 }
206 return result;
207 }
208
209 Node *MemNode::optimize_memory_chain(Node *mchain, const TypePtr *t_adr, Node *load, PhaseGVN *phase) {
210 const TypeOopPtr* t_oop = t_adr->isa_oopptr();
211 if (t_oop == nullptr)
212 return mchain; // don't try to optimize non-oop types
213 Node* result = optimize_simple_memory_chain(mchain, t_oop, load, phase);
214 bool is_instance = t_oop->is_known_instance_field();
215 PhaseIterGVN *igvn = phase->is_IterGVN();
216 if (is_instance && igvn != nullptr && result->is_Phi()) {
217 PhiNode *mphi = result->as_Phi();
218 assert(mphi->bottom_type() == Type::MEMORY, "memory phi required");
219 const TypePtr *t = mphi->adr_type();
220 bool do_split = false;
221 // In the following cases, Load memory input can be further optimized based on
222 // its precise address type
223 if (t == TypePtr::BOTTOM || t == TypeRawPtr::BOTTOM ) {
224 do_split = true;
225 } else if (t->isa_oopptr() && !t->is_oopptr()->is_known_instance()) {
226 const TypeOopPtr* mem_t =
227 t->is_oopptr()->cast_to_exactness(true)
228 ->is_oopptr()->cast_to_ptr_type(t_oop->ptr())
229 ->is_oopptr()->cast_to_instance_id(t_oop->instance_id());
230 if (t_oop->is_aryptr()) {
231 mem_t = mem_t->is_aryptr()
232 ->cast_to_stable(t_oop->is_aryptr()->is_stable())
233 ->cast_to_size(t_oop->is_aryptr()->size())
234 ->with_offset(t_oop->is_aryptr()->offset())
235 ->is_aryptr();
236 }
237 do_split = mem_t == t_oop;
238 }
239 if (do_split) {
240 // clone the Phi with our address type
241 result = mphi->split_out_instance(t_adr, igvn);
242 } else {
243 assert(phase->C->get_alias_index(t) == phase->C->get_alias_index(t_adr), "correct memory chain");
244 }
245 }
246 return result;
247 }
248
249 static Node *step_through_mergemem(PhaseGVN *phase, MergeMemNode *mmem, const TypePtr *tp, const TypePtr *adr_check, outputStream *st) {
250 uint alias_idx = phase->C->get_alias_index(tp);
251 Node *mem = mmem;
252 #ifdef ASSERT
253 {
254 // Check that current type is consistent with the alias index used during graph construction
255 assert(alias_idx >= Compile::AliasIdxRaw, "must not be a bad alias_idx");
256 bool consistent = adr_check == nullptr || adr_check->empty() ||
257 phase->C->must_alias(adr_check, alias_idx );
258 // Sometimes dead array references collapse to a[-1], a[-2], or a[-3]
259 if( !consistent && adr_check != nullptr && !adr_check->empty() &&
260 tp->isa_aryptr() && tp->offset() == Type::OffsetBot &&
261 adr_check->isa_aryptr() && adr_check->offset() != Type::OffsetBot &&
262 ( adr_check->offset() == arrayOopDesc::length_offset_in_bytes() ||
263 adr_check->offset() == oopDesc::klass_offset_in_bytes() ||
264 adr_check->offset() == oopDesc::mark_offset_in_bytes() ) ) {
265 // don't assert if it is dead code.
266 consistent = true;
267 }
268 if( !consistent ) {
269 st->print("alias_idx==%d, adr_check==", alias_idx);
270 if( adr_check == nullptr ) {
271 st->print("null");
272 } else {
273 adr_check->dump();
274 }
275 st->cr();
276 print_alias_types();
277 assert(consistent, "adr_check must match alias idx");
278 }
279 }
280 #endif
281 // TypeOopPtr::NOTNULL+any is an OOP with unknown offset - generally
282 // means an array I have not precisely typed yet. Do not do any
283 // alias stuff with it any time soon.
284 const TypeOopPtr *toop = tp->isa_oopptr();
285 if (tp->base() != Type::AnyPtr &&
286 !(toop &&
287 toop->isa_instptr() &&
288 toop->is_instptr()->instance_klass()->is_java_lang_Object() &&
289 toop->offset() == Type::OffsetBot)) {
290 // compress paths and change unreachable cycles to TOP
291 // If not, we can update the input infinitely along a MergeMem cycle
292 // Equivalent code in PhiNode::Ideal
293 Node* m = phase->transform(mmem);
294 // If transformed to a MergeMem, get the desired slice
295 // Otherwise the returned node represents memory for every slice
296 mem = (m->is_MergeMem())? m->as_MergeMem()->memory_at(alias_idx) : m;
297 // Update input if it is progress over what we have now
298 }
299 return mem;
300 }
301
302 //--------------------------Ideal_common---------------------------------------
303 // Look for degenerate control and memory inputs. Bypass MergeMem inputs.
304 // Unhook non-raw memories from complete (macro-expanded) initializations.
305 Node *MemNode::Ideal_common(PhaseGVN *phase, bool can_reshape) {
306 // If our control input is a dead region, kill all below the region
307 Node *ctl = in(MemNode::Control);
308 if (ctl && remove_dead_region(phase, can_reshape))
309 return this;
310 ctl = in(MemNode::Control);
311 // Don't bother trying to transform a dead node
312 if (ctl && ctl->is_top()) return NodeSentinel;
313
314 PhaseIterGVN *igvn = phase->is_IterGVN();
315 // Wait if control on the worklist.
316 if (ctl && can_reshape && igvn != nullptr) {
317 Node* bol = nullptr;
318 Node* cmp = nullptr;
319 if (ctl->in(0)->is_If()) {
320 assert(ctl->is_IfTrue() || ctl->is_IfFalse(), "sanity");
321 bol = ctl->in(0)->in(1);
322 if (bol->is_Bool())
323 cmp = ctl->in(0)->in(1)->in(1);
324 }
325 if (igvn->_worklist.member(ctl) ||
326 (bol != nullptr && igvn->_worklist.member(bol)) ||
327 (cmp != nullptr && igvn->_worklist.member(cmp)) ) {
328 // This control path may be dead.
329 // Delay this memory node transformation until the control is processed.
330 igvn->_worklist.push(this);
331 return NodeSentinel; // caller will return null
332 }
333 }
334 // Ignore if memory is dead, or self-loop
335 Node *mem = in(MemNode::Memory);
336 if (phase->type( mem ) == Type::TOP) return NodeSentinel; // caller will return null
337 assert(mem != this, "dead loop in MemNode::Ideal");
338
339 if (can_reshape && igvn != nullptr && igvn->_worklist.member(mem)) {
340 // This memory slice may be dead.
341 // Delay this mem node transformation until the memory is processed.
342 igvn->_worklist.push(this);
343 return NodeSentinel; // caller will return null
344 }
345
346 Node *address = in(MemNode::Address);
347 const Type *t_adr = phase->type(address);
348 if (t_adr == Type::TOP) return NodeSentinel; // caller will return null
349
350 if (can_reshape && is_unsafe_access() && (t_adr == TypePtr::NULL_PTR)) {
351 // Unsafe off-heap access with zero address. Remove access and other control users
352 // to not confuse optimizations and add a HaltNode to fail if this is ever executed.
353 assert(ctl != nullptr, "unsafe accesses should be control dependent");
354 for (DUIterator_Fast imax, i = ctl->fast_outs(imax); i < imax; i++) {
355 Node* u = ctl->fast_out(i);
356 if (u != ctl) {
357 igvn->rehash_node_delayed(u);
358 int nb = u->replace_edge(ctl, phase->C->top(), igvn);
359 --i, imax -= nb;
360 }
361 }
362 Node* frame = igvn->transform(new ParmNode(phase->C->start(), TypeFunc::FramePtr));
363 Node* halt = igvn->transform(new HaltNode(ctl, frame, "unsafe off-heap access with zero address"));
364 phase->C->root()->add_req(halt);
365 return this;
366 }
367
368 if (can_reshape && igvn != nullptr &&
369 (igvn->_worklist.member(address) ||
370 (igvn->_worklist.size() > 0 && t_adr != adr_type())) ) {
371 // The address's base and type may change when the address is processed.
372 // Delay this mem node transformation until the address is processed.
373 igvn->_worklist.push(this);
374 return NodeSentinel; // caller will return null
375 }
376
377 // Do NOT remove or optimize the next lines: ensure a new alias index
378 // is allocated for an oop pointer type before Escape Analysis.
379 // Note: C++ will not remove it since the call has side effect.
380 if (t_adr->isa_oopptr()) {
381 int alias_idx = phase->C->get_alias_index(t_adr->is_ptr());
382 }
383
384 Node* base = nullptr;
385 if (address->is_AddP()) {
386 base = address->in(AddPNode::Base);
387 }
388 if (base != nullptr && phase->type(base)->higher_equal(TypePtr::NULL_PTR) &&
389 !t_adr->isa_rawptr()) {
390 // Note: raw address has TOP base and top->higher_equal(TypePtr::NULL_PTR) is true.
391 // Skip this node optimization if its address has TOP base.
392 return NodeSentinel; // caller will return null
393 }
394
395 // Avoid independent memory operations
396 Node* old_mem = mem;
397
398 // The code which unhooks non-raw memories from complete (macro-expanded)
399 // initializations was removed. After macro-expansion all stores caught
400 // by Initialize node became raw stores and there is no information
401 // which memory slices they modify. So it is unsafe to move any memory
402 // operation above these stores. Also in most cases hooked non-raw memories
403 // were already unhooked by using information from detect_ptr_independence()
404 // and find_previous_store().
405
406 if (mem->is_MergeMem()) {
407 MergeMemNode* mmem = mem->as_MergeMem();
408 const TypePtr *tp = t_adr->is_ptr();
409
410 mem = step_through_mergemem(phase, mmem, tp, adr_type(), tty);
411 }
412
413 if (mem != old_mem) {
414 set_req_X(MemNode::Memory, mem, phase);
415 if (phase->type(mem) == Type::TOP) return NodeSentinel;
416 return this;
417 }
418
419 // let the subclass continue analyzing...
420 return nullptr;
421 }
422
423 // Helper function for proving some simple control dominations.
424 // Attempt to prove that all control inputs of 'dom' dominate 'sub'.
425 // Already assumes that 'dom' is available at 'sub', and that 'sub'
426 // is not a constant (dominated by the method's StartNode).
427 // Used by MemNode::find_previous_store to prove that the
428 // control input of a memory operation predates (dominates)
429 // an allocation it wants to look past.
430 bool MemNode::all_controls_dominate(Node* dom, Node* sub) {
431 if (dom == nullptr || dom->is_top() || sub == nullptr || sub->is_top())
432 return false; // Conservative answer for dead code
433
434 // Check 'dom'. Skip Proj and CatchProj nodes.
435 dom = dom->find_exact_control(dom);
436 if (dom == nullptr || dom->is_top())
437 return false; // Conservative answer for dead code
438
439 if (dom == sub) {
440 // For the case when, for example, 'sub' is Initialize and the original
441 // 'dom' is Proj node of the 'sub'.
442 return false;
443 }
444
445 if (dom->is_Con() || dom->is_Start() || dom->is_Root() || dom == sub)
446 return true;
447
448 // 'dom' dominates 'sub' if its control edge and control edges
449 // of all its inputs dominate or equal to sub's control edge.
450
451 // Currently 'sub' is either Allocate, Initialize or Start nodes.
452 // Or Region for the check in LoadNode::Ideal();
453 // 'sub' should have sub->in(0) != nullptr.
454 assert(sub->is_Allocate() || sub->is_Initialize() || sub->is_Start() ||
455 sub->is_Region() || sub->is_Call(), "expecting only these nodes");
456
457 // Get control edge of 'sub'.
458 Node* orig_sub = sub;
459 sub = sub->find_exact_control(sub->in(0));
460 if (sub == nullptr || sub->is_top())
461 return false; // Conservative answer for dead code
462
463 assert(sub->is_CFG(), "expecting control");
464
465 if (sub == dom)
466 return true;
467
468 if (sub->is_Start() || sub->is_Root())
469 return false;
470
471 {
472 // Check all control edges of 'dom'.
473
474 ResourceMark rm;
475 Node_List nlist;
476 Unique_Node_List dom_list;
477
478 dom_list.push(dom);
479 bool only_dominating_controls = false;
480
481 for (uint next = 0; next < dom_list.size(); next++) {
482 Node* n = dom_list.at(next);
483 if (n == orig_sub)
484 return false; // One of dom's inputs dominated by sub.
485 if (!n->is_CFG() && n->pinned()) {
486 // Check only own control edge for pinned non-control nodes.
487 n = n->find_exact_control(n->in(0));
488 if (n == nullptr || n->is_top())
489 return false; // Conservative answer for dead code
490 assert(n->is_CFG(), "expecting control");
491 dom_list.push(n);
492 } else if (n->is_Con() || n->is_Start() || n->is_Root()) {
493 only_dominating_controls = true;
494 } else if (n->is_CFG()) {
495 if (n->dominates(sub, nlist))
496 only_dominating_controls = true;
497 else
498 return false;
499 } else {
500 // First, own control edge.
501 Node* m = n->find_exact_control(n->in(0));
502 if (m != nullptr) {
503 if (m->is_top())
504 return false; // Conservative answer for dead code
505 dom_list.push(m);
506 }
507 // Now, the rest of edges.
508 uint cnt = n->req();
509 for (uint i = 1; i < cnt; i++) {
510 m = n->find_exact_control(n->in(i));
511 if (m == nullptr || m->is_top())
512 continue;
513 dom_list.push(m);
514 }
515 }
516 }
517 return only_dominating_controls;
518 }
519 }
520
521 //---------------------detect_ptr_independence---------------------------------
522 // Used by MemNode::find_previous_store to prove that two base
523 // pointers are never equal.
524 // The pointers are accompanied by their associated allocations,
525 // if any, which have been previously discovered by the caller.
526 bool MemNode::detect_ptr_independence(Node* p1, AllocateNode* a1,
527 Node* p2, AllocateNode* a2,
528 PhaseTransform* phase) {
529 // Attempt to prove that these two pointers cannot be aliased.
530 // They may both manifestly be allocations, and they should differ.
531 // Or, if they are not both allocations, they can be distinct constants.
532 // Otherwise, one is an allocation and the other a pre-existing value.
533 if (a1 == nullptr && a2 == nullptr) { // neither an allocation
534 return (p1 != p2) && p1->is_Con() && p2->is_Con();
535 } else if (a1 != nullptr && a2 != nullptr) { // both allocations
536 return (a1 != a2);
537 } else if (a1 != nullptr) { // one allocation a1
538 // (Note: p2->is_Con implies p2->in(0)->is_Root, which dominates.)
539 return all_controls_dominate(p2, a1);
540 } else { //(a2 != null) // one allocation a2
541 return all_controls_dominate(p1, a2);
542 }
543 return false;
544 }
545
546
547 // Find an arraycopy ac that produces the memory state represented by parameter mem.
548 // Return ac if
549 // (a) can_see_stored_value=true and ac must have set the value for this load or if
550 // (b) can_see_stored_value=false and ac could have set the value for this load or if
551 // (c) can_see_stored_value=false and ac cannot have set the value for this load.
552 // In case (c) change the parameter mem to the memory input of ac to skip it
553 // when searching stored value.
554 // Otherwise return null.
555 Node* LoadNode::find_previous_arraycopy(PhaseValues* phase, Node* ld_alloc, Node*& mem, bool can_see_stored_value) const {
556 ArrayCopyNode* ac = find_array_copy_clone(phase, ld_alloc, mem);
557 if (ac != nullptr) {
558 Node* ld_addp = in(MemNode::Address);
559 Node* src = ac->in(ArrayCopyNode::Src);
560 const TypeAryPtr* ary_t = phase->type(src)->isa_aryptr();
561
562 // This is a load from a cloned array. The corresponding arraycopy ac must
563 // have set the value for the load and we can return ac but only if the load
564 // is known to be within bounds. This is checked below.
565 if (ary_t != nullptr && ld_addp->is_AddP()) {
566 Node* ld_offs = ld_addp->in(AddPNode::Offset);
567 BasicType ary_elem = ary_t->elem()->array_element_basic_type();
568 jlong header = arrayOopDesc::base_offset_in_bytes(ary_elem);
569 jlong elemsize = type2aelembytes(ary_elem);
570
571 const TypeX* ld_offs_t = phase->type(ld_offs)->isa_intptr_t();
572 const TypeInt* sizetype = ary_t->size();
573
574 if (ld_offs_t->_lo >= header && ld_offs_t->_hi < (sizetype->_lo * elemsize + header)) {
575 // The load is known to be within bounds. It receives its value from ac.
576 return ac;
577 }
578 // The load is known to be out-of-bounds.
579 }
580 // The load could be out-of-bounds. It must not be hoisted but must remain
581 // dependent on the runtime range check. This is achieved by returning null.
582 } else if (mem->is_Proj() && mem->in(0) != nullptr && mem->in(0)->is_ArrayCopy()) {
583 ArrayCopyNode* ac = mem->in(0)->as_ArrayCopy();
584
585 if (ac->is_arraycopy_validated() ||
586 ac->is_copyof_validated() ||
587 ac->is_copyofrange_validated()) {
588 Node* ld_addp = in(MemNode::Address);
589 if (ld_addp->is_AddP()) {
590 Node* ld_base = ld_addp->in(AddPNode::Address);
591 Node* ld_offs = ld_addp->in(AddPNode::Offset);
592
593 Node* dest = ac->in(ArrayCopyNode::Dest);
594
595 if (dest == ld_base) {
596 const TypeX* ld_offs_t = phase->type(ld_offs)->isa_intptr_t();
597 assert(!ld_offs_t->empty(), "dead reference should be checked already");
598 // Take into account vector or unsafe access size
599 jlong ld_size_in_bytes = (jlong)memory_size();
600 jlong offset_hi = ld_offs_t->_hi + ld_size_in_bytes - 1;
601 offset_hi = MIN2(offset_hi, (jlong)(TypeX::MAX->_hi)); // Take care for overflow in 32-bit VM
602 if (ac->modifies(ld_offs_t->_lo, (intptr_t)offset_hi, phase, can_see_stored_value)) {
603 return ac;
604 }
605 if (!can_see_stored_value) {
606 mem = ac->in(TypeFunc::Memory);
607 return ac;
608 }
609 }
610 }
611 }
612 }
613 return nullptr;
614 }
615
616 ArrayCopyNode* MemNode::find_array_copy_clone(PhaseValues* phase, Node* ld_alloc, Node* mem) const {
617 if (mem->is_Proj() && mem->in(0) != nullptr && (mem->in(0)->Opcode() == Op_MemBarStoreStore ||
618 mem->in(0)->Opcode() == Op_MemBarCPUOrder)) {
619 if (ld_alloc != nullptr) {
620 // Check if there is an array copy for a clone
621 Node* mb = mem->in(0);
622 ArrayCopyNode* ac = nullptr;
623 if (mb->in(0) != nullptr && mb->in(0)->is_Proj() &&
624 mb->in(0)->in(0) != nullptr && mb->in(0)->in(0)->is_ArrayCopy()) {
625 ac = mb->in(0)->in(0)->as_ArrayCopy();
626 } else {
627 // Step over GC barrier when ReduceInitialCardMarks is disabled
628 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
629 Node* control_proj_ac = bs->step_over_gc_barrier(mb->in(0));
630
631 if (control_proj_ac->is_Proj() && control_proj_ac->in(0)->is_ArrayCopy()) {
632 ac = control_proj_ac->in(0)->as_ArrayCopy();
633 }
634 }
635
636 if (ac != nullptr && ac->is_clonebasic()) {
637 AllocateNode* alloc = AllocateNode::Ideal_allocation(ac->in(ArrayCopyNode::Dest), phase);
638 if (alloc != nullptr && alloc == ld_alloc) {
639 return ac;
640 }
641 }
642 }
643 }
644 return nullptr;
645 }
646
647 // The logic for reordering loads and stores uses four steps:
648 // (a) Walk carefully past stores and initializations which we
649 // can prove are independent of this load.
650 // (b) Observe that the next memory state makes an exact match
651 // with self (load or store), and locate the relevant store.
652 // (c) Ensure that, if we were to wire self directly to the store,
653 // the optimizer would fold it up somehow.
654 // (d) Do the rewiring, and return, depending on some other part of
655 // the optimizer to fold up the load.
656 // This routine handles steps (a) and (b). Steps (c) and (d) are
657 // specific to loads and stores, so they are handled by the callers.
658 // (Currently, only LoadNode::Ideal has steps (c), (d). More later.)
659 //
660 Node* MemNode::find_previous_store(PhaseValues* phase) {
661 Node* ctrl = in(MemNode::Control);
662 Node* adr = in(MemNode::Address);
663 intptr_t offset = 0;
664 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
665 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
666
667 if (offset == Type::OffsetBot)
668 return nullptr; // cannot unalias unless there are precise offsets
669
670 const bool adr_maybe_raw = check_if_adr_maybe_raw(adr);
671 const TypeOopPtr *addr_t = adr->bottom_type()->isa_oopptr();
672
673 intptr_t size_in_bytes = memory_size();
674
675 Node* mem = in(MemNode::Memory); // start searching here...
676
677 int cnt = 50; // Cycle limiter
678 for (;;) { // While we can dance past unrelated stores...
679 if (--cnt < 0) break; // Caught in cycle or a complicated dance?
680
681 Node* prev = mem;
682 if (mem->is_Store()) {
683 Node* st_adr = mem->in(MemNode::Address);
684 intptr_t st_offset = 0;
685 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
686 if (st_base == nullptr)
687 break; // inscrutable pointer
688
689 // For raw accesses it's not enough to prove that constant offsets don't intersect.
690 // We need the bases to be the equal in order for the offset check to make sense.
691 if ((adr_maybe_raw || check_if_adr_maybe_raw(st_adr)) && st_base != base) {
692 break;
693 }
694
695 if (st_offset != offset && st_offset != Type::OffsetBot) {
696 const int MAX_STORE = MAX2(BytesPerLong, (int)MaxVectorSize);
697 assert(mem->as_Store()->memory_size() <= MAX_STORE, "");
698 if (st_offset >= offset + size_in_bytes ||
699 st_offset <= offset - MAX_STORE ||
700 st_offset <= offset - mem->as_Store()->memory_size()) {
701 // Success: The offsets are provably independent.
702 // (You may ask, why not just test st_offset != offset and be done?
703 // The answer is that stores of different sizes can co-exist
704 // in the same sequence of RawMem effects. We sometimes initialize
705 // a whole 'tile' of array elements with a single jint or jlong.)
706 mem = mem->in(MemNode::Memory);
707 continue; // (a) advance through independent store memory
708 }
709 }
710 if (st_base != base &&
711 detect_ptr_independence(base, alloc,
712 st_base,
713 AllocateNode::Ideal_allocation(st_base, phase),
714 phase)) {
715 // Success: The bases are provably independent.
716 mem = mem->in(MemNode::Memory);
717 continue; // (a) advance through independent store memory
718 }
719
720 // (b) At this point, if the bases or offsets do not agree, we lose,
721 // since we have not managed to prove 'this' and 'mem' independent.
722 if (st_base == base && st_offset == offset) {
723 return mem; // let caller handle steps (c), (d)
724 }
725
726 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
727 InitializeNode* st_init = mem->in(0)->as_Initialize();
728 AllocateNode* st_alloc = st_init->allocation();
729 if (st_alloc == nullptr)
730 break; // something degenerated
731 bool known_identical = false;
732 bool known_independent = false;
733 if (alloc == st_alloc)
734 known_identical = true;
735 else if (alloc != nullptr)
736 known_independent = true;
737 else if (all_controls_dominate(this, st_alloc))
738 known_independent = true;
739
740 if (known_independent) {
741 // The bases are provably independent: Either they are
742 // manifestly distinct allocations, or else the control
743 // of this load dominates the store's allocation.
744 int alias_idx = phase->C->get_alias_index(adr_type());
745 if (alias_idx == Compile::AliasIdxRaw) {
746 mem = st_alloc->in(TypeFunc::Memory);
747 } else {
748 mem = st_init->memory(alias_idx);
749 }
750 continue; // (a) advance through independent store memory
751 }
752
753 // (b) at this point, if we are not looking at a store initializing
754 // the same allocation we are loading from, we lose.
755 if (known_identical) {
756 // From caller, can_see_stored_value will consult find_captured_store.
757 return mem; // let caller handle steps (c), (d)
758 }
759
760 } else if (find_previous_arraycopy(phase, alloc, mem, false) != nullptr) {
761 if (prev != mem) {
762 // Found an arraycopy but it doesn't affect that load
763 continue;
764 }
765 // Found an arraycopy that may affect that load
766 return mem;
767 } else if (addr_t != nullptr && addr_t->is_known_instance_field()) {
768 // Can't use optimize_simple_memory_chain() since it needs PhaseGVN.
769 if (mem->is_Proj() && mem->in(0)->is_Call()) {
770 // ArrayCopyNodes processed here as well.
771 CallNode *call = mem->in(0)->as_Call();
772 if (!call->may_modify(addr_t, phase)) {
773 mem = call->in(TypeFunc::Memory);
774 continue; // (a) advance through independent call memory
775 }
776 } else if (mem->is_Proj() && mem->in(0)->is_MemBar()) {
777 ArrayCopyNode* ac = nullptr;
778 if (ArrayCopyNode::may_modify(addr_t, mem->in(0)->as_MemBar(), phase, ac)) {
779 break;
780 }
781 mem = mem->in(0)->in(TypeFunc::Memory);
782 continue; // (a) advance through independent MemBar memory
783 } else if (mem->is_ClearArray()) {
784 if (ClearArrayNode::step_through(&mem, (uint)addr_t->instance_id(), phase)) {
785 // (the call updated 'mem' value)
786 continue; // (a) advance through independent allocation memory
787 } else {
788 // Can not bypass initialization of the instance
789 // we are looking for.
790 return mem;
791 }
792 } else if (mem->is_MergeMem()) {
793 int alias_idx = phase->C->get_alias_index(adr_type());
794 mem = mem->as_MergeMem()->memory_at(alias_idx);
795 continue; // (a) advance through independent MergeMem memory
796 }
797 }
798
799 // Unless there is an explicit 'continue', we must bail out here,
800 // because 'mem' is an inscrutable memory state (e.g., a call).
801 break;
802 }
803
804 return nullptr; // bail out
805 }
806
807 //----------------------calculate_adr_type-------------------------------------
808 // Helper function. Notices when the given type of address hits top or bottom.
809 // Also, asserts a cross-check of the type against the expected address type.
810 const TypePtr* MemNode::calculate_adr_type(const Type* t, const TypePtr* cross_check) {
811 if (t == Type::TOP) return nullptr; // does not touch memory any more?
812 #ifdef ASSERT
813 if (!VerifyAliases || VMError::is_error_reported() || Node::in_dump()) cross_check = nullptr;
814 #endif
815 const TypePtr* tp = t->isa_ptr();
816 if (tp == nullptr) {
817 assert(cross_check == nullptr || cross_check == TypePtr::BOTTOM, "expected memory type must be wide");
818 return TypePtr::BOTTOM; // touches lots of memory
819 } else {
820 #ifdef ASSERT
821 // %%%% [phh] We don't check the alias index if cross_check is
822 // TypeRawPtr::BOTTOM. Needs to be investigated.
823 if (cross_check != nullptr &&
824 cross_check != TypePtr::BOTTOM &&
825 cross_check != TypeRawPtr::BOTTOM) {
826 // Recheck the alias index, to see if it has changed (due to a bug).
827 Compile* C = Compile::current();
828 assert(C->get_alias_index(cross_check) == C->get_alias_index(tp),
829 "must stay in the original alias category");
830 // The type of the address must be contained in the adr_type,
831 // disregarding "null"-ness.
832 // (We make an exception for TypeRawPtr::BOTTOM, which is a bit bucket.)
833 const TypePtr* tp_notnull = tp->join(TypePtr::NOTNULL)->is_ptr();
834 assert(cross_check->meet(tp_notnull) == cross_check->remove_speculative(),
835 "real address must not escape from expected memory type");
836 }
837 #endif
838 return tp;
839 }
840 }
841
842 //=============================================================================
843 // Should LoadNode::Ideal() attempt to remove control edges?
844 bool LoadNode::can_remove_control() const {
845 return !has_pinned_control_dependency();
846 }
847 uint LoadNode::size_of() const { return sizeof(*this); }
848 bool LoadNode::cmp( const Node &n ) const
849 { return !Type::cmp( _type, ((LoadNode&)n)._type ); }
850 const Type *LoadNode::bottom_type() const { return _type; }
851 uint LoadNode::ideal_reg() const {
852 return _type->ideal_reg();
853 }
854
855 #ifndef PRODUCT
856 void LoadNode::dump_spec(outputStream *st) const {
857 MemNode::dump_spec(st);
858 if( !Verbose && !WizardMode ) {
859 // standard dump does this in Verbose and WizardMode
860 st->print(" #"); _type->dump_on(st);
861 }
862 if (!depends_only_on_test()) {
863 st->print(" (does not depend only on test, ");
864 if (control_dependency() == UnknownControl) {
865 st->print("unknown control");
866 } else if (control_dependency() == Pinned) {
867 st->print("pinned");
868 } else if (adr_type() == TypeRawPtr::BOTTOM) {
869 st->print("raw access");
870 } else {
871 st->print("unknown reason");
872 }
873 st->print(")");
874 }
875 }
876 #endif
877
878 #ifdef ASSERT
879 //----------------------------is_immutable_value-------------------------------
880 // Helper function to allow a raw load without control edge for some cases
881 bool LoadNode::is_immutable_value(Node* adr) {
882 if (adr->is_AddP() && adr->in(AddPNode::Base)->is_top() &&
883 adr->in(AddPNode::Address)->Opcode() == Op_ThreadLocal) {
884
885 jlong offset = adr->in(AddPNode::Offset)->find_intptr_t_con(-1);
886 int offsets[] = {
887 in_bytes(JavaThread::osthread_offset()),
888 in_bytes(JavaThread::threadObj_offset()),
889 in_bytes(JavaThread::vthread_offset()),
890 in_bytes(JavaThread::scopedValueCache_offset()),
891 };
892
893 for (size_t i = 0; i < sizeof offsets / sizeof offsets[0]; i++) {
894 if (offset == offsets[i]) {
895 return true;
896 }
897 }
898 }
899
900 return false;
901 }
902 #endif
903
904 //----------------------------LoadNode::make-----------------------------------
905 // Polymorphic factory method:
906 Node* LoadNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, const Type* rt, BasicType bt, MemOrd mo,
907 ControlDependency control_dependency, bool require_atomic_access, bool unaligned, bool mismatched, bool unsafe, uint8_t barrier_data) {
908 Compile* C = gvn.C;
909
910 // sanity check the alias category against the created node type
911 assert(!(adr_type->isa_oopptr() &&
912 adr_type->offset() == oopDesc::klass_offset_in_bytes()),
913 "use LoadKlassNode instead");
914 assert(!(adr_type->isa_aryptr() &&
915 adr_type->offset() == arrayOopDesc::length_offset_in_bytes()),
916 "use LoadRangeNode instead");
917 // Check control edge of raw loads
918 assert( ctl != nullptr || C->get_alias_index(adr_type) != Compile::AliasIdxRaw ||
919 // oop will be recorded in oop map if load crosses safepoint
920 rt->isa_oopptr() || is_immutable_value(adr),
921 "raw memory operations should have control edge");
922 LoadNode* load = nullptr;
923 switch (bt) {
924 case T_BOOLEAN: load = new LoadUBNode(ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break;
925 case T_BYTE: load = new LoadBNode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break;
926 case T_INT: load = new LoadINode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break;
927 case T_CHAR: load = new LoadUSNode(ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break;
928 case T_SHORT: load = new LoadSNode (ctl, mem, adr, adr_type, rt->is_int(), mo, control_dependency); break;
929 case T_LONG: load = new LoadLNode (ctl, mem, adr, adr_type, rt->is_long(), mo, control_dependency, require_atomic_access); break;
930 case T_FLOAT: load = new LoadFNode (ctl, mem, adr, adr_type, rt, mo, control_dependency); break;
931 case T_DOUBLE: load = new LoadDNode (ctl, mem, adr, adr_type, rt, mo, control_dependency, require_atomic_access); break;
932 case T_ADDRESS: load = new LoadPNode (ctl, mem, adr, adr_type, rt->is_ptr(), mo, control_dependency); break;
933 case T_OBJECT:
934 #ifdef _LP64
935 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
936 load = new LoadNNode(ctl, mem, adr, adr_type, rt->make_narrowoop(), mo, control_dependency);
937 } else
938 #endif
939 {
940 assert(!adr->bottom_type()->is_ptr_to_narrowoop() && !adr->bottom_type()->is_ptr_to_narrowklass(), "should have got back a narrow oop");
941 load = new LoadPNode(ctl, mem, adr, adr_type, rt->is_ptr(), mo, control_dependency);
942 }
943 break;
944 default:
945 ShouldNotReachHere();
946 break;
947 }
948 assert(load != nullptr, "LoadNode should have been created");
949 if (unaligned) {
950 load->set_unaligned_access();
951 }
952 if (mismatched) {
953 load->set_mismatched_access();
954 }
955 if (unsafe) {
956 load->set_unsafe_access();
957 }
958 load->set_barrier_data(barrier_data);
959 if (load->Opcode() == Op_LoadN) {
960 Node* ld = gvn.transform(load);
961 return new DecodeNNode(ld, ld->bottom_type()->make_ptr());
962 }
963
964 return load;
965 }
966
967 //------------------------------hash-------------------------------------------
968 uint LoadNode::hash() const {
969 // unroll addition of interesting fields
970 return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address);
971 }
972
973 static bool skip_through_membars(Compile::AliasType* atp, const TypeInstPtr* tp, bool eliminate_boxing) {
974 if ((atp != nullptr) && (atp->index() >= Compile::AliasIdxRaw)) {
975 bool non_volatile = (atp->field() != nullptr) && !atp->field()->is_volatile();
976 bool is_stable_ary = FoldStableValues &&
977 (tp != nullptr) && (tp->isa_aryptr() != nullptr) &&
978 tp->isa_aryptr()->is_stable();
979
980 return (eliminate_boxing && non_volatile) || is_stable_ary;
981 }
982
983 return false;
984 }
985
986 // Is the value loaded previously stored by an arraycopy? If so return
987 // a load node that reads from the source array so we may be able to
988 // optimize out the ArrayCopy node later.
989 Node* LoadNode::can_see_arraycopy_value(Node* st, PhaseGVN* phase) const {
990 Node* ld_adr = in(MemNode::Address);
991 intptr_t ld_off = 0;
992 AllocateNode* ld_alloc = AllocateNode::Ideal_allocation(ld_adr, phase, ld_off);
993 Node* ac = find_previous_arraycopy(phase, ld_alloc, st, true);
994 if (ac != nullptr) {
995 assert(ac->is_ArrayCopy(), "what kind of node can this be?");
996
997 Node* mem = ac->in(TypeFunc::Memory);
998 Node* ctl = ac->in(0);
999 Node* src = ac->in(ArrayCopyNode::Src);
1000
1001 if (!ac->as_ArrayCopy()->is_clonebasic() && !phase->type(src)->isa_aryptr()) {
1002 return nullptr;
1003 }
1004
1005 LoadNode* ld = clone()->as_Load();
1006 Node* addp = in(MemNode::Address)->clone();
1007 if (ac->as_ArrayCopy()->is_clonebasic()) {
1008 assert(ld_alloc != nullptr, "need an alloc");
1009 assert(addp->is_AddP(), "address must be addp");
1010 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1011 assert(bs->step_over_gc_barrier(addp->in(AddPNode::Base)) == bs->step_over_gc_barrier(ac->in(ArrayCopyNode::Dest)), "strange pattern");
1012 assert(bs->step_over_gc_barrier(addp->in(AddPNode::Address)) == bs->step_over_gc_barrier(ac->in(ArrayCopyNode::Dest)), "strange pattern");
1013 addp->set_req(AddPNode::Base, src);
1014 addp->set_req(AddPNode::Address, src);
1015 } else {
1016 assert(ac->as_ArrayCopy()->is_arraycopy_validated() ||
1017 ac->as_ArrayCopy()->is_copyof_validated() ||
1018 ac->as_ArrayCopy()->is_copyofrange_validated(), "only supported cases");
1019 assert(addp->in(AddPNode::Base) == addp->in(AddPNode::Address), "should be");
1020 addp->set_req(AddPNode::Base, src);
1021 addp->set_req(AddPNode::Address, src);
1022
1023 const TypeAryPtr* ary_t = phase->type(in(MemNode::Address))->isa_aryptr();
1024 BasicType ary_elem = ary_t->isa_aryptr()->elem()->array_element_basic_type();
1025 if (is_reference_type(ary_elem, true)) ary_elem = T_OBJECT;
1026
1027 uint header = arrayOopDesc::base_offset_in_bytes(ary_elem);
1028 uint shift = exact_log2(type2aelembytes(ary_elem));
1029
1030 Node* diff = phase->transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
1031 #ifdef _LP64
1032 diff = phase->transform(new ConvI2LNode(diff));
1033 #endif
1034 diff = phase->transform(new LShiftXNode(diff, phase->intcon(shift)));
1035
1036 Node* offset = phase->transform(new AddXNode(addp->in(AddPNode::Offset), diff));
1037 addp->set_req(AddPNode::Offset, offset);
1038 }
1039 addp = phase->transform(addp);
1040 #ifdef ASSERT
1041 const TypePtr* adr_type = phase->type(addp)->is_ptr();
1042 ld->_adr_type = adr_type;
1043 #endif
1044 ld->set_req(MemNode::Address, addp);
1045 ld->set_req(0, ctl);
1046 ld->set_req(MemNode::Memory, mem);
1047 // load depends on the tests that validate the arraycopy
1048 ld->_control_dependency = UnknownControl;
1049 return ld;
1050 }
1051 return nullptr;
1052 }
1053
1054
1055 //---------------------------can_see_stored_value------------------------------
1056 // This routine exists to make sure this set of tests is done the same
1057 // everywhere. We need to make a coordinated change: first LoadNode::Ideal
1058 // will change the graph shape in a way which makes memory alive twice at the
1059 // same time (uses the Oracle model of aliasing), then some
1060 // LoadXNode::Identity will fold things back to the equivalence-class model
1061 // of aliasing.
1062 Node* MemNode::can_see_stored_value(Node* st, PhaseValues* phase) const {
1063 Node* ld_adr = in(MemNode::Address);
1064 intptr_t ld_off = 0;
1065 Node* ld_base = AddPNode::Ideal_base_and_offset(ld_adr, phase, ld_off);
1066 Node* ld_alloc = AllocateNode::Ideal_allocation(ld_base, phase);
1067 const TypeInstPtr* tp = phase->type(ld_adr)->isa_instptr();
1068 Compile::AliasType* atp = (tp != nullptr) ? phase->C->alias_type(tp) : nullptr;
1069 // This is more general than load from boxing objects.
1070 if (skip_through_membars(atp, tp, phase->C->eliminate_boxing())) {
1071 uint alias_idx = atp->index();
1072 Node* result = nullptr;
1073 Node* current = st;
1074 // Skip through chains of MemBarNodes checking the MergeMems for
1075 // new states for the slice of this load. Stop once any other
1076 // kind of node is encountered. Loads from final memory can skip
1077 // through any kind of MemBar but normal loads shouldn't skip
1078 // through MemBarAcquire since the could allow them to move out of
1079 // a synchronized region. It is not safe to step over MemBarCPUOrder,
1080 // because alias info above them may be inaccurate (e.g., due to
1081 // mixed/mismatched unsafe accesses).
1082 bool is_final_mem = !atp->is_rewritable();
1083 while (current->is_Proj()) {
1084 int opc = current->in(0)->Opcode();
1085 if ((is_final_mem && (opc == Op_MemBarAcquire ||
1086 opc == Op_MemBarAcquireLock ||
1087 opc == Op_LoadFence)) ||
1088 opc == Op_MemBarRelease ||
1089 opc == Op_StoreFence ||
1090 opc == Op_MemBarReleaseLock ||
1091 opc == Op_MemBarStoreStore ||
1092 opc == Op_StoreStoreFence) {
1093 Node* mem = current->in(0)->in(TypeFunc::Memory);
1094 if (mem->is_MergeMem()) {
1095 MergeMemNode* merge = mem->as_MergeMem();
1096 Node* new_st = merge->memory_at(alias_idx);
1097 if (new_st == merge->base_memory()) {
1098 // Keep searching
1099 current = new_st;
1100 continue;
1101 }
1102 // Save the new memory state for the slice and fall through
1103 // to exit.
1104 result = new_st;
1105 }
1106 }
1107 break;
1108 }
1109 if (result != nullptr) {
1110 st = result;
1111 }
1112 }
1113
1114 // Loop around twice in the case Load -> Initialize -> Store.
1115 // (See PhaseIterGVN::add_users_to_worklist, which knows about this case.)
1116 for (int trip = 0; trip <= 1; trip++) {
1117
1118 if (st->is_Store()) {
1119 Node* st_adr = st->in(MemNode::Address);
1120 if (st_adr != ld_adr) {
1121 // Try harder before giving up. Unify base pointers with casts (e.g., raw/non-raw pointers).
1122 intptr_t st_off = 0;
1123 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_off);
1124 if (ld_base == nullptr) return nullptr;
1125 if (st_base == nullptr) return nullptr;
1126 if (!ld_base->eqv_uncast(st_base, /*keep_deps=*/true)) return nullptr;
1127 if (ld_off != st_off) return nullptr;
1128 if (ld_off == Type::OffsetBot) return nullptr;
1129 // Same base, same offset.
1130 // Possible improvement for arrays: check index value instead of absolute offset.
1131
1132 // At this point we have proven something like this setup:
1133 // B = << base >>
1134 // L = LoadQ(AddP(Check/CastPP(B), #Off))
1135 // S = StoreQ(AddP( B , #Off), V)
1136 // (Actually, we haven't yet proven the Q's are the same.)
1137 // In other words, we are loading from a casted version of
1138 // the same pointer-and-offset that we stored to.
1139 // Casted version may carry a dependency and it is respected.
1140 // Thus, we are able to replace L by V.
1141 }
1142 // Now prove that we have a LoadQ matched to a StoreQ, for some Q.
1143 if (store_Opcode() != st->Opcode()) {
1144 return nullptr;
1145 }
1146 // LoadVector/StoreVector needs additional check to ensure the types match.
1147 if (st->is_StoreVector()) {
1148 const TypeVect* in_vt = st->as_StoreVector()->vect_type();
1149 const TypeVect* out_vt = as_LoadVector()->vect_type();
1150 if (in_vt != out_vt) {
1151 return nullptr;
1152 }
1153 }
1154 return st->in(MemNode::ValueIn);
1155 }
1156
1157 // A load from a freshly-created object always returns zero.
1158 // (This can happen after LoadNode::Ideal resets the load's memory input
1159 // to find_captured_store, which returned InitializeNode::zero_memory.)
1160 if (st->is_Proj() && st->in(0)->is_Allocate() &&
1161 (st->in(0) == ld_alloc) &&
1162 (ld_off >= st->in(0)->as_Allocate()->minimum_header_size())) {
1163 // return a zero value for the load's basic type
1164 // (This is one of the few places where a generic PhaseTransform
1165 // can create new nodes. Think of it as lazily manifesting
1166 // virtually pre-existing constants.)
1167 if (memory_type() != T_VOID) {
1168 if (ReduceBulkZeroing || find_array_copy_clone(phase, ld_alloc, in(MemNode::Memory)) == nullptr) {
1169 // If ReduceBulkZeroing is disabled, we need to check if the allocation does not belong to an
1170 // ArrayCopyNode clone. If it does, then we cannot assume zero since the initialization is done
1171 // by the ArrayCopyNode.
1172 return phase->zerocon(memory_type());
1173 }
1174 } else {
1175 // TODO: materialize all-zero vector constant
1176 assert(!isa_Load() || as_Load()->type()->isa_vect(), "");
1177 }
1178 }
1179
1180 // A load from an initialization barrier can match a captured store.
1181 if (st->is_Proj() && st->in(0)->is_Initialize()) {
1182 InitializeNode* init = st->in(0)->as_Initialize();
1183 AllocateNode* alloc = init->allocation();
1184 if ((alloc != nullptr) && (alloc == ld_alloc)) {
1185 // examine a captured store value
1186 st = init->find_captured_store(ld_off, memory_size(), phase);
1187 if (st != nullptr) {
1188 continue; // take one more trip around
1189 }
1190 }
1191 }
1192
1193 // Load boxed value from result of valueOf() call is input parameter.
1194 if (this->is_Load() && ld_adr->is_AddP() &&
1195 (tp != nullptr) && tp->is_ptr_to_boxed_value()) {
1196 intptr_t ignore = 0;
1197 Node* base = AddPNode::Ideal_base_and_offset(ld_adr, phase, ignore);
1198 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1199 base = bs->step_over_gc_barrier(base);
1200 if (base != nullptr && base->is_Proj() &&
1201 base->as_Proj()->_con == TypeFunc::Parms &&
1202 base->in(0)->is_CallStaticJava() &&
1203 base->in(0)->as_CallStaticJava()->is_boxing_method()) {
1204 return base->in(0)->in(TypeFunc::Parms);
1205 }
1206 }
1207
1208 break;
1209 }
1210
1211 return nullptr;
1212 }
1213
1214 //----------------------is_instance_field_load_with_local_phi------------------
1215 bool LoadNode::is_instance_field_load_with_local_phi(Node* ctrl) {
1216 if( in(Memory)->is_Phi() && in(Memory)->in(0) == ctrl &&
1217 in(Address)->is_AddP() ) {
1218 const TypeOopPtr* t_oop = in(Address)->bottom_type()->isa_oopptr();
1219 // Only instances and boxed values.
1220 if( t_oop != nullptr &&
1221 (t_oop->is_ptr_to_boxed_value() ||
1222 t_oop->is_known_instance_field()) &&
1223 t_oop->offset() != Type::OffsetBot &&
1224 t_oop->offset() != Type::OffsetTop) {
1225 return true;
1226 }
1227 }
1228 return false;
1229 }
1230
1231 //------------------------------Identity---------------------------------------
1232 // Loads are identity if previous store is to same address
1233 Node* LoadNode::Identity(PhaseGVN* phase) {
1234 // If the previous store-maker is the right kind of Store, and the store is
1235 // to the same address, then we are equal to the value stored.
1236 Node* mem = in(Memory);
1237 Node* value = can_see_stored_value(mem, phase);
1238 if( value ) {
1239 // byte, short & char stores truncate naturally.
1240 // A load has to load the truncated value which requires
1241 // some sort of masking operation and that requires an
1242 // Ideal call instead of an Identity call.
1243 if (memory_size() < BytesPerInt) {
1244 // If the input to the store does not fit with the load's result type,
1245 // it must be truncated via an Ideal call.
1246 if (!phase->type(value)->higher_equal(phase->type(this)))
1247 return this;
1248 }
1249 // (This works even when value is a Con, but LoadNode::Value
1250 // usually runs first, producing the singleton type of the Con.)
1251 if (!has_pinned_control_dependency() || value->is_Con()) {
1252 return value;
1253 } else {
1254 return this;
1255 }
1256 }
1257
1258 if (has_pinned_control_dependency()) {
1259 return this;
1260 }
1261 // Search for an existing data phi which was generated before for the same
1262 // instance's field to avoid infinite generation of phis in a loop.
1263 Node *region = mem->in(0);
1264 if (is_instance_field_load_with_local_phi(region)) {
1265 const TypeOopPtr *addr_t = in(Address)->bottom_type()->isa_oopptr();
1266 int this_index = phase->C->get_alias_index(addr_t);
1267 int this_offset = addr_t->offset();
1268 int this_iid = addr_t->instance_id();
1269 if (!addr_t->is_known_instance() &&
1270 addr_t->is_ptr_to_boxed_value()) {
1271 // Use _idx of address base (could be Phi node) for boxed values.
1272 intptr_t ignore = 0;
1273 Node* base = AddPNode::Ideal_base_and_offset(in(Address), phase, ignore);
1274 if (base == nullptr) {
1275 return this;
1276 }
1277 this_iid = base->_idx;
1278 }
1279 const Type* this_type = bottom_type();
1280 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1281 Node* phi = region->fast_out(i);
1282 if (phi->is_Phi() && phi != mem &&
1283 phi->as_Phi()->is_same_inst_field(this_type, (int)mem->_idx, this_iid, this_index, this_offset)) {
1284 return phi;
1285 }
1286 }
1287 }
1288
1289 return this;
1290 }
1291
1292 // Construct an equivalent unsigned load.
1293 Node* LoadNode::convert_to_unsigned_load(PhaseGVN& gvn) {
1294 BasicType bt = T_ILLEGAL;
1295 const Type* rt = nullptr;
1296 switch (Opcode()) {
1297 case Op_LoadUB: return this;
1298 case Op_LoadUS: return this;
1299 case Op_LoadB: bt = T_BOOLEAN; rt = TypeInt::UBYTE; break;
1300 case Op_LoadS: bt = T_CHAR; rt = TypeInt::CHAR; break;
1301 default:
1302 assert(false, "no unsigned variant: %s", Name());
1303 return nullptr;
1304 }
1305 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address),
1306 raw_adr_type(), rt, bt, _mo, _control_dependency,
1307 false /*require_atomic_access*/, is_unaligned_access(), is_mismatched_access());
1308 }
1309
1310 // Construct an equivalent signed load.
1311 Node* LoadNode::convert_to_signed_load(PhaseGVN& gvn) {
1312 BasicType bt = T_ILLEGAL;
1313 const Type* rt = nullptr;
1314 switch (Opcode()) {
1315 case Op_LoadUB: bt = T_BYTE; rt = TypeInt::BYTE; break;
1316 case Op_LoadUS: bt = T_SHORT; rt = TypeInt::SHORT; break;
1317 case Op_LoadB: // fall through
1318 case Op_LoadS: // fall through
1319 case Op_LoadI: // fall through
1320 case Op_LoadL: return this;
1321 default:
1322 assert(false, "no signed variant: %s", Name());
1323 return nullptr;
1324 }
1325 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address),
1326 raw_adr_type(), rt, bt, _mo, _control_dependency,
1327 false /*require_atomic_access*/, is_unaligned_access(), is_mismatched_access());
1328 }
1329
1330 bool LoadNode::has_reinterpret_variant(const Type* rt) {
1331 BasicType bt = rt->basic_type();
1332 switch (Opcode()) {
1333 case Op_LoadI: return (bt == T_FLOAT);
1334 case Op_LoadL: return (bt == T_DOUBLE);
1335 case Op_LoadF: return (bt == T_INT);
1336 case Op_LoadD: return (bt == T_LONG);
1337
1338 default: return false;
1339 }
1340 }
1341
1342 Node* LoadNode::convert_to_reinterpret_load(PhaseGVN& gvn, const Type* rt) {
1343 BasicType bt = rt->basic_type();
1344 assert(has_reinterpret_variant(rt), "no reinterpret variant: %s %s", Name(), type2name(bt));
1345 bool is_mismatched = is_mismatched_access();
1346 const TypeRawPtr* raw_type = gvn.type(in(MemNode::Memory))->isa_rawptr();
1347 if (raw_type == nullptr) {
1348 is_mismatched = true; // conservatively match all non-raw accesses as mismatched
1349 }
1350 const int op = Opcode();
1351 bool require_atomic_access = (op == Op_LoadL && ((LoadLNode*)this)->require_atomic_access()) ||
1352 (op == Op_LoadD && ((LoadDNode*)this)->require_atomic_access());
1353 return LoadNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address),
1354 raw_adr_type(), rt, bt, _mo, _control_dependency,
1355 require_atomic_access, is_unaligned_access(), is_mismatched);
1356 }
1357
1358 bool StoreNode::has_reinterpret_variant(const Type* vt) {
1359 BasicType bt = vt->basic_type();
1360 switch (Opcode()) {
1361 case Op_StoreI: return (bt == T_FLOAT);
1362 case Op_StoreL: return (bt == T_DOUBLE);
1363 case Op_StoreF: return (bt == T_INT);
1364 case Op_StoreD: return (bt == T_LONG);
1365
1366 default: return false;
1367 }
1368 }
1369
1370 Node* StoreNode::convert_to_reinterpret_store(PhaseGVN& gvn, Node* val, const Type* vt) {
1371 BasicType bt = vt->basic_type();
1372 assert(has_reinterpret_variant(vt), "no reinterpret variant: %s %s", Name(), type2name(bt));
1373 const int op = Opcode();
1374 bool require_atomic_access = (op == Op_StoreL && ((StoreLNode*)this)->require_atomic_access()) ||
1375 (op == Op_StoreD && ((StoreDNode*)this)->require_atomic_access());
1376 StoreNode* st = StoreNode::make(gvn, in(MemNode::Control), in(MemNode::Memory), in(MemNode::Address),
1377 raw_adr_type(), val, bt, _mo, require_atomic_access);
1378
1379 bool is_mismatched = is_mismatched_access();
1380 const TypeRawPtr* raw_type = gvn.type(in(MemNode::Memory))->isa_rawptr();
1381 if (raw_type == nullptr) {
1382 is_mismatched = true; // conservatively match all non-raw accesses as mismatched
1383 }
1384 if (is_mismatched) {
1385 st->set_mismatched_access();
1386 }
1387 return st;
1388 }
1389
1390 // We're loading from an object which has autobox behaviour.
1391 // If this object is result of a valueOf call we'll have a phi
1392 // merging a newly allocated object and a load from the cache.
1393 // We want to replace this load with the original incoming
1394 // argument to the valueOf call.
1395 Node* LoadNode::eliminate_autobox(PhaseIterGVN* igvn) {
1396 assert(igvn->C->eliminate_boxing(), "sanity");
1397 intptr_t ignore = 0;
1398 Node* base = AddPNode::Ideal_base_and_offset(in(Address), igvn, ignore);
1399 if ((base == nullptr) || base->is_Phi()) {
1400 // Push the loads from the phi that comes from valueOf up
1401 // through it to allow elimination of the loads and the recovery
1402 // of the original value. It is done in split_through_phi().
1403 return nullptr;
1404 } else if (base->is_Load() ||
1405 (base->is_DecodeN() && base->in(1)->is_Load())) {
1406 // Eliminate the load of boxed value for integer types from the cache
1407 // array by deriving the value from the index into the array.
1408 // Capture the offset of the load and then reverse the computation.
1409
1410 // Get LoadN node which loads a boxing object from 'cache' array.
1411 if (base->is_DecodeN()) {
1412 base = base->in(1);
1413 }
1414 if (!base->in(Address)->is_AddP()) {
1415 return nullptr; // Complex address
1416 }
1417 AddPNode* address = base->in(Address)->as_AddP();
1418 Node* cache_base = address->in(AddPNode::Base);
1419 if ((cache_base != nullptr) && cache_base->is_DecodeN()) {
1420 // Get ConP node which is static 'cache' field.
1421 cache_base = cache_base->in(1);
1422 }
1423 if ((cache_base != nullptr) && cache_base->is_Con()) {
1424 const TypeAryPtr* base_type = cache_base->bottom_type()->isa_aryptr();
1425 if ((base_type != nullptr) && base_type->is_autobox_cache()) {
1426 Node* elements[4];
1427 int shift = exact_log2(type2aelembytes(T_OBJECT));
1428 int count = address->unpack_offsets(elements, ARRAY_SIZE(elements));
1429 if (count > 0 && elements[0]->is_Con() &&
1430 (count == 1 ||
1431 (count == 2 && elements[1]->Opcode() == Op_LShiftX &&
1432 elements[1]->in(2) == igvn->intcon(shift)))) {
1433 ciObjArray* array = base_type->const_oop()->as_obj_array();
1434 // Fetch the box object cache[0] at the base of the array and get its value
1435 ciInstance* box = array->obj_at(0)->as_instance();
1436 ciInstanceKlass* ik = box->klass()->as_instance_klass();
1437 assert(ik->is_box_klass(), "sanity");
1438 assert(ik->nof_nonstatic_fields() == 1, "change following code");
1439 if (ik->nof_nonstatic_fields() == 1) {
1440 // This should be true nonstatic_field_at requires calling
1441 // nof_nonstatic_fields so check it anyway
1442 ciConstant c = box->field_value(ik->nonstatic_field_at(0));
1443 BasicType bt = c.basic_type();
1444 // Only integer types have boxing cache.
1445 assert(bt == T_BOOLEAN || bt == T_CHAR ||
1446 bt == T_BYTE || bt == T_SHORT ||
1447 bt == T_INT || bt == T_LONG, "wrong type = %s", type2name(bt));
1448 jlong cache_low = (bt == T_LONG) ? c.as_long() : c.as_int();
1449 if (cache_low != (int)cache_low) {
1450 return nullptr; // should not happen since cache is array indexed by value
1451 }
1452 jlong offset = arrayOopDesc::base_offset_in_bytes(T_OBJECT) - (cache_low << shift);
1453 if (offset != (int)offset) {
1454 return nullptr; // should not happen since cache is array indexed by value
1455 }
1456 // Add up all the offsets making of the address of the load
1457 Node* result = elements[0];
1458 for (int i = 1; i < count; i++) {
1459 result = igvn->transform(new AddXNode(result, elements[i]));
1460 }
1461 // Remove the constant offset from the address and then
1462 result = igvn->transform(new AddXNode(result, igvn->MakeConX(-(int)offset)));
1463 // remove the scaling of the offset to recover the original index.
1464 if (result->Opcode() == Op_LShiftX && result->in(2) == igvn->intcon(shift)) {
1465 // Peel the shift off directly but wrap it in a dummy node
1466 // since Ideal can't return existing nodes
1467 igvn->_worklist.push(result); // remove dead node later
1468 result = new RShiftXNode(result->in(1), igvn->intcon(0));
1469 } else if (result->is_Add() && result->in(2)->is_Con() &&
1470 result->in(1)->Opcode() == Op_LShiftX &&
1471 result->in(1)->in(2) == igvn->intcon(shift)) {
1472 // We can't do general optimization: ((X<<Z) + Y) >> Z ==> X + (Y>>Z)
1473 // but for boxing cache access we know that X<<Z will not overflow
1474 // (there is range check) so we do this optimizatrion by hand here.
1475 igvn->_worklist.push(result); // remove dead node later
1476 Node* add_con = new RShiftXNode(result->in(2), igvn->intcon(shift));
1477 result = new AddXNode(result->in(1)->in(1), igvn->transform(add_con));
1478 } else {
1479 result = new RShiftXNode(result, igvn->intcon(shift));
1480 }
1481 #ifdef _LP64
1482 if (bt != T_LONG) {
1483 result = new ConvL2INode(igvn->transform(result));
1484 }
1485 #else
1486 if (bt == T_LONG) {
1487 result = new ConvI2LNode(igvn->transform(result));
1488 }
1489 #endif
1490 // Boxing/unboxing can be done from signed & unsigned loads (e.g. LoadUB -> ... -> LoadB pair).
1491 // Need to preserve unboxing load type if it is unsigned.
1492 switch(this->Opcode()) {
1493 case Op_LoadUB:
1494 result = new AndINode(igvn->transform(result), igvn->intcon(0xFF));
1495 break;
1496 case Op_LoadUS:
1497 result = new AndINode(igvn->transform(result), igvn->intcon(0xFFFF));
1498 break;
1499 }
1500 return result;
1501 }
1502 }
1503 }
1504 }
1505 }
1506 return nullptr;
1507 }
1508
1509 static bool stable_phi(PhiNode* phi, PhaseGVN *phase) {
1510 Node* region = phi->in(0);
1511 if (region == nullptr) {
1512 return false; // Wait stable graph
1513 }
1514 uint cnt = phi->req();
1515 for (uint i = 1; i < cnt; i++) {
1516 Node* rc = region->in(i);
1517 if (rc == nullptr || phase->type(rc) == Type::TOP)
1518 return false; // Wait stable graph
1519 Node* in = phi->in(i);
1520 if (in == nullptr || phase->type(in) == Type::TOP)
1521 return false; // Wait stable graph
1522 }
1523 return true;
1524 }
1525 //------------------------------split_through_phi------------------------------
1526 // Split instance or boxed field load through Phi.
1527 Node* LoadNode::split_through_phi(PhaseGVN* phase) {
1528 if (req() > 3) {
1529 assert(is_LoadVector() && Opcode() != Op_LoadVector, "load has too many inputs");
1530 // LoadVector subclasses such as LoadVectorMasked have extra inputs that the logic below doesn't take into account
1531 return nullptr;
1532 }
1533 Node* mem = in(Memory);
1534 Node* address = in(Address);
1535 const TypeOopPtr *t_oop = phase->type(address)->isa_oopptr();
1536
1537 assert((t_oop != nullptr) &&
1538 (t_oop->is_known_instance_field() ||
1539 t_oop->is_ptr_to_boxed_value()), "invalid conditions");
1540
1541 Compile* C = phase->C;
1542 intptr_t ignore = 0;
1543 Node* base = AddPNode::Ideal_base_and_offset(address, phase, ignore);
1544 bool base_is_phi = (base != nullptr) && base->is_Phi();
1545 bool load_boxed_values = t_oop->is_ptr_to_boxed_value() && C->aggressive_unboxing() &&
1546 (base != nullptr) && (base == address->in(AddPNode::Base)) &&
1547 phase->type(base)->higher_equal(TypePtr::NOTNULL);
1548
1549 if (!((mem->is_Phi() || base_is_phi) &&
1550 (load_boxed_values || t_oop->is_known_instance_field()))) {
1551 return nullptr; // memory is not Phi
1552 }
1553
1554 if (mem->is_Phi()) {
1555 if (!stable_phi(mem->as_Phi(), phase)) {
1556 return nullptr; // Wait stable graph
1557 }
1558 uint cnt = mem->req();
1559 // Check for loop invariant memory.
1560 if (cnt == 3) {
1561 for (uint i = 1; i < cnt; i++) {
1562 Node* in = mem->in(i);
1563 Node* m = optimize_memory_chain(in, t_oop, this, phase);
1564 if (m == mem) {
1565 if (i == 1) {
1566 // if the first edge was a loop, check second edge too.
1567 // If both are replaceable - we are in an infinite loop
1568 Node *n = optimize_memory_chain(mem->in(2), t_oop, this, phase);
1569 if (n == mem) {
1570 break;
1571 }
1572 }
1573 set_req(Memory, mem->in(cnt - i));
1574 return this; // made change
1575 }
1576 }
1577 }
1578 }
1579 if (base_is_phi) {
1580 if (!stable_phi(base->as_Phi(), phase)) {
1581 return nullptr; // Wait stable graph
1582 }
1583 uint cnt = base->req();
1584 // Check for loop invariant memory.
1585 if (cnt == 3) {
1586 for (uint i = 1; i < cnt; i++) {
1587 if (base->in(i) == base) {
1588 return nullptr; // Wait stable graph
1589 }
1590 }
1591 }
1592 }
1593
1594 // Split through Phi (see original code in loopopts.cpp).
1595 assert(C->have_alias_type(t_oop), "instance should have alias type");
1596
1597 // Do nothing here if Identity will find a value
1598 // (to avoid infinite chain of value phis generation).
1599 if (this != Identity(phase)) {
1600 return nullptr;
1601 }
1602
1603 // Select Region to split through.
1604 Node* region;
1605 if (!base_is_phi) {
1606 assert(mem->is_Phi(), "sanity");
1607 region = mem->in(0);
1608 // Skip if the region dominates some control edge of the address.
1609 if (!MemNode::all_controls_dominate(address, region))
1610 return nullptr;
1611 } else if (!mem->is_Phi()) {
1612 assert(base_is_phi, "sanity");
1613 region = base->in(0);
1614 // Skip if the region dominates some control edge of the memory.
1615 if (!MemNode::all_controls_dominate(mem, region))
1616 return nullptr;
1617 } else if (base->in(0) != mem->in(0)) {
1618 assert(base_is_phi && mem->is_Phi(), "sanity");
1619 if (MemNode::all_controls_dominate(mem, base->in(0))) {
1620 region = base->in(0);
1621 } else if (MemNode::all_controls_dominate(address, mem->in(0))) {
1622 region = mem->in(0);
1623 } else {
1624 return nullptr; // complex graph
1625 }
1626 } else {
1627 assert(base->in(0) == mem->in(0), "sanity");
1628 region = mem->in(0);
1629 }
1630
1631 const Type* this_type = this->bottom_type();
1632 int this_index = C->get_alias_index(t_oop);
1633 int this_offset = t_oop->offset();
1634 int this_iid = t_oop->instance_id();
1635 if (!t_oop->is_known_instance() && load_boxed_values) {
1636 // Use _idx of address base for boxed values.
1637 this_iid = base->_idx;
1638 }
1639 PhaseIterGVN* igvn = phase->is_IterGVN();
1640 Node* phi = new PhiNode(region, this_type, nullptr, mem->_idx, this_iid, this_index, this_offset);
1641 for (uint i = 1; i < region->req(); i++) {
1642 Node* x;
1643 Node* the_clone = nullptr;
1644 Node* in = region->in(i);
1645 if (region->is_CountedLoop() && region->as_Loop()->is_strip_mined() && i == LoopNode::EntryControl &&
1646 in != nullptr && in->is_OuterStripMinedLoop()) {
1647 // No node should go in the outer strip mined loop
1648 in = in->in(LoopNode::EntryControl);
1649 }
1650 if (in == nullptr || in == C->top()) {
1651 x = C->top(); // Dead path? Use a dead data op
1652 } else {
1653 x = this->clone(); // Else clone up the data op
1654 the_clone = x; // Remember for possible deletion.
1655 // Alter data node to use pre-phi inputs
1656 if (this->in(0) == region) {
1657 x->set_req(0, in);
1658 } else {
1659 x->set_req(0, nullptr);
1660 }
1661 if (mem->is_Phi() && (mem->in(0) == region)) {
1662 x->set_req(Memory, mem->in(i)); // Use pre-Phi input for the clone.
1663 }
1664 if (address->is_Phi() && address->in(0) == region) {
1665 x->set_req(Address, address->in(i)); // Use pre-Phi input for the clone
1666 }
1667 if (base_is_phi && (base->in(0) == region)) {
1668 Node* base_x = base->in(i); // Clone address for loads from boxed objects.
1669 Node* adr_x = phase->transform(new AddPNode(base_x,base_x,address->in(AddPNode::Offset)));
1670 x->set_req(Address, adr_x);
1671 }
1672 }
1673 // Check for a 'win' on some paths
1674 const Type *t = x->Value(igvn);
1675
1676 bool singleton = t->singleton();
1677
1678 // See comments in PhaseIdealLoop::split_thru_phi().
1679 if (singleton && t == Type::TOP) {
1680 singleton &= region->is_Loop() && (i != LoopNode::EntryControl);
1681 }
1682
1683 if (singleton) {
1684 x = igvn->makecon(t);
1685 } else {
1686 // We now call Identity to try to simplify the cloned node.
1687 // Note that some Identity methods call phase->type(this).
1688 // Make sure that the type array is big enough for
1689 // our new node, even though we may throw the node away.
1690 // (This tweaking with igvn only works because x is a new node.)
1691 igvn->set_type(x, t);
1692 // If x is a TypeNode, capture any more-precise type permanently into Node
1693 // otherwise it will be not updated during igvn->transform since
1694 // igvn->type(x) is set to x->Value() already.
1695 x->raise_bottom_type(t);
1696 Node* y = x->Identity(igvn);
1697 if (y != x) {
1698 x = y;
1699 } else {
1700 y = igvn->hash_find_insert(x);
1701 if (y) {
1702 x = y;
1703 } else {
1704 // Else x is a new node we are keeping
1705 // We do not need register_new_node_with_optimizer
1706 // because set_type has already been called.
1707 igvn->_worklist.push(x);
1708 }
1709 }
1710 }
1711 if (x != the_clone && the_clone != nullptr) {
1712 igvn->remove_dead_node(the_clone);
1713 }
1714 phi->set_req(i, x);
1715 }
1716 // Record Phi
1717 igvn->register_new_node_with_optimizer(phi);
1718 return phi;
1719 }
1720
1721 AllocateNode* LoadNode::is_new_object_mark_load(PhaseGVN *phase) const {
1722 if (Opcode() == Op_LoadX) {
1723 Node* address = in(MemNode::Address);
1724 AllocateNode* alloc = AllocateNode::Ideal_allocation(address, phase);
1725 Node* mem = in(MemNode::Memory);
1726 if (alloc != nullptr && mem->is_Proj() &&
1727 mem->in(0) != nullptr &&
1728 mem->in(0) == alloc->initialization() &&
1729 alloc->initialization()->proj_out_or_null(0) != nullptr) {
1730 return alloc;
1731 }
1732 }
1733 return nullptr;
1734 }
1735
1736
1737 //------------------------------Ideal------------------------------------------
1738 // If the load is from Field memory and the pointer is non-null, it might be possible to
1739 // zero out the control input.
1740 // If the offset is constant and the base is an object allocation,
1741 // try to hook me up to the exact initializing store.
1742 Node *LoadNode::Ideal(PhaseGVN *phase, bool can_reshape) {
1743 if (has_pinned_control_dependency()) {
1744 return nullptr;
1745 }
1746 Node* p = MemNode::Ideal_common(phase, can_reshape);
1747 if (p) return (p == NodeSentinel) ? nullptr : p;
1748
1749 Node* ctrl = in(MemNode::Control);
1750 Node* address = in(MemNode::Address);
1751 bool progress = false;
1752
1753 bool addr_mark = ((phase->type(address)->isa_oopptr() || phase->type(address)->isa_narrowoop()) &&
1754 phase->type(address)->is_ptr()->offset() == oopDesc::mark_offset_in_bytes());
1755
1756 // Skip up past a SafePoint control. Cannot do this for Stores because
1757 // pointer stores & cardmarks must stay on the same side of a SafePoint.
1758 if( ctrl != nullptr && ctrl->Opcode() == Op_SafePoint &&
1759 phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw &&
1760 !addr_mark &&
1761 (depends_only_on_test() || has_unknown_control_dependency())) {
1762 ctrl = ctrl->in(0);
1763 set_req(MemNode::Control,ctrl);
1764 progress = true;
1765 }
1766
1767 intptr_t ignore = 0;
1768 Node* base = AddPNode::Ideal_base_and_offset(address, phase, ignore);
1769 if (base != nullptr
1770 && phase->C->get_alias_index(phase->type(address)->is_ptr()) != Compile::AliasIdxRaw) {
1771 // Check for useless control edge in some common special cases
1772 if (in(MemNode::Control) != nullptr
1773 && can_remove_control()
1774 && phase->type(base)->higher_equal(TypePtr::NOTNULL)
1775 && all_controls_dominate(base, phase->C->start())) {
1776 // A method-invariant, non-null address (constant or 'this' argument).
1777 set_req(MemNode::Control, nullptr);
1778 progress = true;
1779 }
1780 }
1781
1782 Node* mem = in(MemNode::Memory);
1783 const TypePtr *addr_t = phase->type(address)->isa_ptr();
1784
1785 if (can_reshape && (addr_t != nullptr)) {
1786 // try to optimize our memory input
1787 Node* opt_mem = MemNode::optimize_memory_chain(mem, addr_t, this, phase);
1788 if (opt_mem != mem) {
1789 set_req_X(MemNode::Memory, opt_mem, phase);
1790 if (phase->type( opt_mem ) == Type::TOP) return nullptr;
1791 return this;
1792 }
1793 const TypeOopPtr *t_oop = addr_t->isa_oopptr();
1794 if ((t_oop != nullptr) &&
1795 (t_oop->is_known_instance_field() ||
1796 t_oop->is_ptr_to_boxed_value())) {
1797 PhaseIterGVN *igvn = phase->is_IterGVN();
1798 assert(igvn != nullptr, "must be PhaseIterGVN when can_reshape is true");
1799 if (igvn->_worklist.member(opt_mem)) {
1800 // Delay this transformation until memory Phi is processed.
1801 igvn->_worklist.push(this);
1802 return nullptr;
1803 }
1804 // Split instance field load through Phi.
1805 Node* result = split_through_phi(phase);
1806 if (result != nullptr) return result;
1807
1808 if (t_oop->is_ptr_to_boxed_value()) {
1809 Node* result = eliminate_autobox(igvn);
1810 if (result != nullptr) return result;
1811 }
1812 }
1813 }
1814
1815 // Is there a dominating load that loads the same value? Leave
1816 // anything that is not a load of a field/array element (like
1817 // barriers etc.) alone
1818 if (in(0) != nullptr && !adr_type()->isa_rawptr() && can_reshape) {
1819 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) {
1820 Node *use = mem->fast_out(i);
1821 if (use != this &&
1822 use->Opcode() == Opcode() &&
1823 use->in(0) != nullptr &&
1824 use->in(0) != in(0) &&
1825 use->in(Address) == in(Address)) {
1826 Node* ctl = in(0);
1827 for (int i = 0; i < 10 && ctl != nullptr; i++) {
1828 ctl = IfNode::up_one_dom(ctl);
1829 if (ctl == use->in(0)) {
1830 set_req(0, use->in(0));
1831 return this;
1832 }
1833 }
1834 }
1835 }
1836 }
1837
1838 // Check for prior store with a different base or offset; make Load
1839 // independent. Skip through any number of them. Bail out if the stores
1840 // are in an endless dead cycle and report no progress. This is a key
1841 // transform for Reflection. However, if after skipping through the Stores
1842 // we can't then fold up against a prior store do NOT do the transform as
1843 // this amounts to using the 'Oracle' model of aliasing. It leaves the same
1844 // array memory alive twice: once for the hoisted Load and again after the
1845 // bypassed Store. This situation only works if EVERYBODY who does
1846 // anti-dependence work knows how to bypass. I.e. we need all
1847 // anti-dependence checks to ask the same Oracle. Right now, that Oracle is
1848 // the alias index stuff. So instead, peek through Stores and IFF we can
1849 // fold up, do so.
1850 Node* prev_mem = find_previous_store(phase);
1851 if (prev_mem != nullptr) {
1852 Node* value = can_see_arraycopy_value(prev_mem, phase);
1853 if (value != nullptr) {
1854 return value;
1855 }
1856 }
1857 // Steps (a), (b): Walk past independent stores to find an exact match.
1858 if (prev_mem != nullptr && prev_mem != in(MemNode::Memory)) {
1859 // (c) See if we can fold up on the spot, but don't fold up here.
1860 // Fold-up might require truncation (for LoadB/LoadS/LoadUS) or
1861 // just return a prior value, which is done by Identity calls.
1862 if (can_see_stored_value(prev_mem, phase)) {
1863 // Make ready for step (d):
1864 set_req_X(MemNode::Memory, prev_mem, phase);
1865 return this;
1866 }
1867 }
1868
1869 return progress ? this : nullptr;
1870 }
1871
1872 // Helper to recognize certain Klass fields which are invariant across
1873 // some group of array types (e.g., int[] or all T[] where T < Object).
1874 const Type*
1875 LoadNode::load_array_final_field(const TypeKlassPtr *tkls,
1876 ciKlass* klass) const {
1877 if (tkls->offset() == in_bytes(Klass::modifier_flags_offset())) {
1878 // The field is Klass::_modifier_flags. Return its (constant) value.
1879 // (Folds up the 2nd indirection in aClassConstant.getModifiers().)
1880 assert(this->Opcode() == Op_LoadI, "must load an int from _modifier_flags");
1881 return TypeInt::make(klass->modifier_flags());
1882 }
1883 if (tkls->offset() == in_bytes(Klass::access_flags_offset())) {
1884 // The field is Klass::_access_flags. Return its (constant) value.
1885 // (Folds up the 2nd indirection in Reflection.getClassAccessFlags(aClassConstant).)
1886 assert(this->Opcode() == Op_LoadI, "must load an int from _access_flags");
1887 return TypeInt::make(klass->access_flags());
1888 }
1889 if (tkls->offset() == in_bytes(Klass::layout_helper_offset())) {
1890 // The field is Klass::_layout_helper. Return its constant value if known.
1891 assert(this->Opcode() == Op_LoadI, "must load an int from _layout_helper");
1892 return TypeInt::make(klass->layout_helper());
1893 }
1894
1895 // No match.
1896 return nullptr;
1897 }
1898
1899 //------------------------------Value-----------------------------------------
1900 const Type* LoadNode::Value(PhaseGVN* phase) const {
1901 // Either input is TOP ==> the result is TOP
1902 Node* mem = in(MemNode::Memory);
1903 const Type *t1 = phase->type(mem);
1904 if (t1 == Type::TOP) return Type::TOP;
1905 Node* adr = in(MemNode::Address);
1906 const TypePtr* tp = phase->type(adr)->isa_ptr();
1907 if (tp == nullptr || tp->empty()) return Type::TOP;
1908 int off = tp->offset();
1909 assert(off != Type::OffsetTop, "case covered by TypePtr::empty");
1910 Compile* C = phase->C;
1911
1912 // Try to guess loaded type from pointer type
1913 if (tp->isa_aryptr()) {
1914 const TypeAryPtr* ary = tp->is_aryptr();
1915 const Type* t = ary->elem();
1916
1917 // Determine whether the reference is beyond the header or not, by comparing
1918 // the offset against the offset of the start of the array's data.
1919 // Different array types begin at slightly different offsets (12 vs. 16).
1920 // We choose T_BYTE as an example base type that is least restrictive
1921 // as to alignment, which will therefore produce the smallest
1922 // possible base offset.
1923 const int min_base_off = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1924 const bool off_beyond_header = (off >= min_base_off);
1925
1926 // Try to constant-fold a stable array element.
1927 if (FoldStableValues && !is_mismatched_access() && ary->is_stable()) {
1928 // Make sure the reference is not into the header and the offset is constant
1929 ciObject* aobj = ary->const_oop();
1930 if (aobj != nullptr && off_beyond_header && adr->is_AddP() && off != Type::OffsetBot) {
1931 int stable_dimension = (ary->stable_dimension() > 0 ? ary->stable_dimension() - 1 : 0);
1932 const Type* con_type = Type::make_constant_from_array_element(aobj->as_array(), off,
1933 stable_dimension,
1934 memory_type(), is_unsigned());
1935 if (con_type != nullptr) {
1936 return con_type;
1937 }
1938 }
1939 }
1940
1941 // Don't do this for integer types. There is only potential profit if
1942 // the element type t is lower than _type; that is, for int types, if _type is
1943 // more restrictive than t. This only happens here if one is short and the other
1944 // char (both 16 bits), and in those cases we've made an intentional decision
1945 // to use one kind of load over the other. See AndINode::Ideal and 4965907.
1946 // Also, do not try to narrow the type for a LoadKlass, regardless of offset.
1947 //
1948 // Yes, it is possible to encounter an expression like (LoadKlass p1:(AddP x x 8))
1949 // where the _gvn.type of the AddP is wider than 8. This occurs when an earlier
1950 // copy p0 of (AddP x x 8) has been proven equal to p1, and the p0 has been
1951 // subsumed by p1. If p1 is on the worklist but has not yet been re-transformed,
1952 // it is possible that p1 will have a type like Foo*[int+]:NotNull*+any.
1953 // In fact, that could have been the original type of p1, and p1 could have
1954 // had an original form like p1:(AddP x x (LShiftL quux 3)), where the
1955 // expression (LShiftL quux 3) independently optimized to the constant 8.
1956 if ((t->isa_int() == nullptr) && (t->isa_long() == nullptr)
1957 && (_type->isa_vect() == nullptr)
1958 && Opcode() != Op_LoadKlass && Opcode() != Op_LoadNKlass) {
1959 // t might actually be lower than _type, if _type is a unique
1960 // concrete subclass of abstract class t.
1961 if (off_beyond_header || off == Type::OffsetBot) { // is the offset beyond the header?
1962 const Type* jt = t->join_speculative(_type);
1963 // In any case, do not allow the join, per se, to empty out the type.
1964 if (jt->empty() && !t->empty()) {
1965 // This can happen if a interface-typed array narrows to a class type.
1966 jt = _type;
1967 }
1968 #ifdef ASSERT
1969 if (phase->C->eliminate_boxing() && adr->is_AddP()) {
1970 // The pointers in the autobox arrays are always non-null
1971 Node* base = adr->in(AddPNode::Base);
1972 if ((base != nullptr) && base->is_DecodeN()) {
1973 // Get LoadN node which loads IntegerCache.cache field
1974 base = base->in(1);
1975 }
1976 if ((base != nullptr) && base->is_Con()) {
1977 const TypeAryPtr* base_type = base->bottom_type()->isa_aryptr();
1978 if ((base_type != nullptr) && base_type->is_autobox_cache()) {
1979 // It could be narrow oop
1980 assert(jt->make_ptr()->ptr() == TypePtr::NotNull,"sanity");
1981 }
1982 }
1983 }
1984 #endif
1985 return jt;
1986 }
1987 }
1988 } else if (tp->base() == Type::InstPtr) {
1989 assert( off != Type::OffsetBot ||
1990 // arrays can be cast to Objects
1991 !tp->isa_instptr() ||
1992 tp->is_instptr()->instance_klass()->is_java_lang_Object() ||
1993 // unsafe field access may not have a constant offset
1994 C->has_unsafe_access(),
1995 "Field accesses must be precise" );
1996 // For oop loads, we expect the _type to be precise.
1997
1998 // Optimize loads from constant fields.
1999 const TypeInstPtr* tinst = tp->is_instptr();
2000 ciObject* const_oop = tinst->const_oop();
2001 if (!is_mismatched_access() && off != Type::OffsetBot && const_oop != nullptr && const_oop->is_instance()) {
2002 const Type* con_type = Type::make_constant_from_field(const_oop->as_instance(), off, is_unsigned(), memory_type());
2003 if (con_type != nullptr) {
2004 return con_type;
2005 }
2006 }
2007 } else if (tp->base() == Type::KlassPtr || tp->base() == Type::InstKlassPtr || tp->base() == Type::AryKlassPtr) {
2008 assert(off != Type::OffsetBot ||
2009 !tp->isa_instklassptr() ||
2010 // arrays can be cast to Objects
2011 tp->isa_instklassptr()->instance_klass()->is_java_lang_Object() ||
2012 // also allow array-loading from the primary supertype
2013 // array during subtype checks
2014 Opcode() == Op_LoadKlass,
2015 "Field accesses must be precise");
2016 // For klass/static loads, we expect the _type to be precise
2017 } else if (tp->base() == Type::RawPtr && adr->is_Load() && off == 0) {
2018 /* With mirrors being an indirect in the Klass*
2019 * the VM is now using two loads. LoadKlass(LoadP(LoadP(Klass, mirror_offset), zero_offset))
2020 * The LoadP from the Klass has a RawPtr type (see LibraryCallKit::load_mirror_from_klass).
2021 *
2022 * So check the type and klass of the node before the LoadP.
2023 */
2024 Node* adr2 = adr->in(MemNode::Address);
2025 const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr();
2026 if (tkls != nullptr && !StressReflectiveCode) {
2027 if (tkls->is_loaded() && tkls->klass_is_exact() && tkls->offset() == in_bytes(Klass::java_mirror_offset())) {
2028 ciKlass* klass = tkls->exact_klass();
2029 assert(adr->Opcode() == Op_LoadP, "must load an oop from _java_mirror");
2030 assert(Opcode() == Op_LoadP, "must load an oop from _java_mirror");
2031 return TypeInstPtr::make(klass->java_mirror());
2032 }
2033 }
2034 }
2035
2036 const TypeKlassPtr *tkls = tp->isa_klassptr();
2037 if (tkls != nullptr) {
2038 if (tkls->is_loaded() && tkls->klass_is_exact()) {
2039 ciKlass* klass = tkls->exact_klass();
2040 // We are loading a field from a Klass metaobject whose identity
2041 // is known at compile time (the type is "exact" or "precise").
2042 // Check for fields we know are maintained as constants by the VM.
2043 if (tkls->offset() == in_bytes(Klass::super_check_offset_offset())) {
2044 // The field is Klass::_super_check_offset. Return its (constant) value.
2045 // (Folds up type checking code.)
2046 assert(Opcode() == Op_LoadI, "must load an int from _super_check_offset");
2047 return TypeInt::make(klass->super_check_offset());
2048 }
2049 // Compute index into primary_supers array
2050 juint depth = (tkls->offset() - in_bytes(Klass::primary_supers_offset())) / sizeof(Klass*);
2051 // Check for overflowing; use unsigned compare to handle the negative case.
2052 if( depth < ciKlass::primary_super_limit() ) {
2053 // The field is an element of Klass::_primary_supers. Return its (constant) value.
2054 // (Folds up type checking code.)
2055 assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
2056 ciKlass *ss = klass->super_of_depth(depth);
2057 return ss ? TypeKlassPtr::make(ss, Type::trust_interfaces) : TypePtr::NULL_PTR;
2058 }
2059 const Type* aift = load_array_final_field(tkls, klass);
2060 if (aift != nullptr) return aift;
2061 }
2062
2063 // We can still check if we are loading from the primary_supers array at a
2064 // shallow enough depth. Even though the klass is not exact, entries less
2065 // than or equal to its super depth are correct.
2066 if (tkls->is_loaded()) {
2067 ciKlass* klass = nullptr;
2068 if (tkls->isa_instklassptr()) {
2069 klass = tkls->is_instklassptr()->instance_klass();
2070 } else {
2071 int dims;
2072 const Type* inner = tkls->is_aryklassptr()->base_element_type(dims);
2073 if (inner->isa_instklassptr()) {
2074 klass = inner->is_instklassptr()->instance_klass();
2075 klass = ciObjArrayKlass::make(klass, dims);
2076 }
2077 }
2078 if (klass != nullptr) {
2079 // Compute index into primary_supers array
2080 juint depth = (tkls->offset() - in_bytes(Klass::primary_supers_offset())) / sizeof(Klass*);
2081 // Check for overflowing; use unsigned compare to handle the negative case.
2082 if (depth < ciKlass::primary_super_limit() &&
2083 depth <= klass->super_depth()) { // allow self-depth checks to handle self-check case
2084 // The field is an element of Klass::_primary_supers. Return its (constant) value.
2085 // (Folds up type checking code.)
2086 assert(Opcode() == Op_LoadKlass, "must load a klass from _primary_supers");
2087 ciKlass *ss = klass->super_of_depth(depth);
2088 return ss ? TypeKlassPtr::make(ss, Type::trust_interfaces) : TypePtr::NULL_PTR;
2089 }
2090 }
2091 }
2092
2093 // If the type is enough to determine that the thing is not an array,
2094 // we can give the layout_helper a positive interval type.
2095 // This will help short-circuit some reflective code.
2096 if (tkls->offset() == in_bytes(Klass::layout_helper_offset()) &&
2097 tkls->isa_instklassptr() && // not directly typed as an array
2098 !tkls->is_instklassptr()->instance_klass()->is_java_lang_Object() // not the supertype of all T[] and specifically not Serializable & Cloneable
2099 ) {
2100 // Note: When interfaces are reliable, we can narrow the interface
2101 // test to (klass != Serializable && klass != Cloneable).
2102 assert(Opcode() == Op_LoadI, "must load an int from _layout_helper");
2103 jint min_size = Klass::instance_layout_helper(oopDesc::header_size(), false);
2104 // The key property of this type is that it folds up tests
2105 // for array-ness, since it proves that the layout_helper is positive.
2106 // Thus, a generic value like the basic object layout helper works fine.
2107 return TypeInt::make(min_size, max_jint, Type::WidenMin);
2108 }
2109 }
2110
2111 // If we are loading from a freshly-allocated object, produce a zero,
2112 // if the load is provably beyond the header of the object.
2113 // (Also allow a variable load from a fresh array to produce zero.)
2114 const TypeOopPtr *tinst = tp->isa_oopptr();
2115 bool is_instance = (tinst != nullptr) && tinst->is_known_instance_field();
2116 bool is_boxed_value = (tinst != nullptr) && tinst->is_ptr_to_boxed_value();
2117 if (ReduceFieldZeroing || is_instance || is_boxed_value) {
2118 Node* value = can_see_stored_value(mem,phase);
2119 if (value != nullptr && value->is_Con()) {
2120 assert(value->bottom_type()->higher_equal(_type),"sanity");
2121 return value->bottom_type();
2122 }
2123 }
2124
2125 bool is_vect = (_type->isa_vect() != nullptr);
2126 if (is_instance && !is_vect) {
2127 // If we have an instance type and our memory input is the
2128 // programs's initial memory state, there is no matching store,
2129 // so just return a zero of the appropriate type -
2130 // except if it is vectorized - then we have no zero constant.
2131 Node *mem = in(MemNode::Memory);
2132 if (mem->is_Parm() && mem->in(0)->is_Start()) {
2133 assert(mem->as_Parm()->_con == TypeFunc::Memory, "must be memory Parm");
2134 return Type::get_zero_type(_type->basic_type());
2135 }
2136 }
2137
2138 Node* alloc = is_new_object_mark_load(phase);
2139 if (alloc != nullptr) {
2140 return TypeX::make(markWord::prototype().value());
2141 }
2142
2143 return _type;
2144 }
2145
2146 //------------------------------match_edge-------------------------------------
2147 // Do we Match on this edge index or not? Match only the address.
2148 uint LoadNode::match_edge(uint idx) const {
2149 return idx == MemNode::Address;
2150 }
2151
2152 //--------------------------LoadBNode::Ideal--------------------------------------
2153 //
2154 // If the previous store is to the same address as this load,
2155 // and the value stored was larger than a byte, replace this load
2156 // with the value stored truncated to a byte. If no truncation is
2157 // needed, the replacement is done in LoadNode::Identity().
2158 //
2159 Node* LoadBNode::Ideal(PhaseGVN* phase, bool can_reshape) {
2160 Node* mem = in(MemNode::Memory);
2161 Node* value = can_see_stored_value(mem,phase);
2162 if (value != nullptr) {
2163 Node* narrow = Compile::narrow_value(T_BYTE, value, _type, phase, false);
2164 if (narrow != value) {
2165 return narrow;
2166 }
2167 }
2168 // Identity call will handle the case where truncation is not needed.
2169 return LoadNode::Ideal(phase, can_reshape);
2170 }
2171
2172 const Type* LoadBNode::Value(PhaseGVN* phase) const {
2173 Node* mem = in(MemNode::Memory);
2174 Node* value = can_see_stored_value(mem,phase);
2175 if (value != nullptr && value->is_Con() &&
2176 !value->bottom_type()->higher_equal(_type)) {
2177 // If the input to the store does not fit with the load's result type,
2178 // it must be truncated. We can't delay until Ideal call since
2179 // a singleton Value is needed for split_thru_phi optimization.
2180 int con = value->get_int();
2181 return TypeInt::make((con << 24) >> 24);
2182 }
2183 return LoadNode::Value(phase);
2184 }
2185
2186 //--------------------------LoadUBNode::Ideal-------------------------------------
2187 //
2188 // If the previous store is to the same address as this load,
2189 // and the value stored was larger than a byte, replace this load
2190 // with the value stored truncated to a byte. If no truncation is
2191 // needed, the replacement is done in LoadNode::Identity().
2192 //
2193 Node* LoadUBNode::Ideal(PhaseGVN* phase, bool can_reshape) {
2194 Node* mem = in(MemNode::Memory);
2195 Node* value = can_see_stored_value(mem, phase);
2196 if (value != nullptr) {
2197 Node* narrow = Compile::narrow_value(T_BOOLEAN, value, _type, phase, false);
2198 if (narrow != value) {
2199 return narrow;
2200 }
2201 }
2202 // Identity call will handle the case where truncation is not needed.
2203 return LoadNode::Ideal(phase, can_reshape);
2204 }
2205
2206 const Type* LoadUBNode::Value(PhaseGVN* phase) const {
2207 Node* mem = in(MemNode::Memory);
2208 Node* value = can_see_stored_value(mem,phase);
2209 if (value != nullptr && value->is_Con() &&
2210 !value->bottom_type()->higher_equal(_type)) {
2211 // If the input to the store does not fit with the load's result type,
2212 // it must be truncated. We can't delay until Ideal call since
2213 // a singleton Value is needed for split_thru_phi optimization.
2214 int con = value->get_int();
2215 return TypeInt::make(con & 0xFF);
2216 }
2217 return LoadNode::Value(phase);
2218 }
2219
2220 //--------------------------LoadUSNode::Ideal-------------------------------------
2221 //
2222 // If the previous store is to the same address as this load,
2223 // and the value stored was larger than a char, replace this load
2224 // with the value stored truncated to a char. If no truncation is
2225 // needed, the replacement is done in LoadNode::Identity().
2226 //
2227 Node* LoadUSNode::Ideal(PhaseGVN* phase, bool can_reshape) {
2228 Node* mem = in(MemNode::Memory);
2229 Node* value = can_see_stored_value(mem,phase);
2230 if (value != nullptr) {
2231 Node* narrow = Compile::narrow_value(T_CHAR, value, _type, phase, false);
2232 if (narrow != value) {
2233 return narrow;
2234 }
2235 }
2236 // Identity call will handle the case where truncation is not needed.
2237 return LoadNode::Ideal(phase, can_reshape);
2238 }
2239
2240 const Type* LoadUSNode::Value(PhaseGVN* phase) const {
2241 Node* mem = in(MemNode::Memory);
2242 Node* value = can_see_stored_value(mem,phase);
2243 if (value != nullptr && value->is_Con() &&
2244 !value->bottom_type()->higher_equal(_type)) {
2245 // If the input to the store does not fit with the load's result type,
2246 // it must be truncated. We can't delay until Ideal call since
2247 // a singleton Value is needed for split_thru_phi optimization.
2248 int con = value->get_int();
2249 return TypeInt::make(con & 0xFFFF);
2250 }
2251 return LoadNode::Value(phase);
2252 }
2253
2254 //--------------------------LoadSNode::Ideal--------------------------------------
2255 //
2256 // If the previous store is to the same address as this load,
2257 // and the value stored was larger than a short, replace this load
2258 // with the value stored truncated to a short. If no truncation is
2259 // needed, the replacement is done in LoadNode::Identity().
2260 //
2261 Node* LoadSNode::Ideal(PhaseGVN* phase, bool can_reshape) {
2262 Node* mem = in(MemNode::Memory);
2263 Node* value = can_see_stored_value(mem,phase);
2264 if (value != nullptr) {
2265 Node* narrow = Compile::narrow_value(T_SHORT, value, _type, phase, false);
2266 if (narrow != value) {
2267 return narrow;
2268 }
2269 }
2270 // Identity call will handle the case where truncation is not needed.
2271 return LoadNode::Ideal(phase, can_reshape);
2272 }
2273
2274 const Type* LoadSNode::Value(PhaseGVN* phase) const {
2275 Node* mem = in(MemNode::Memory);
2276 Node* value = can_see_stored_value(mem,phase);
2277 if (value != nullptr && value->is_Con() &&
2278 !value->bottom_type()->higher_equal(_type)) {
2279 // If the input to the store does not fit with the load's result type,
2280 // it must be truncated. We can't delay until Ideal call since
2281 // a singleton Value is needed for split_thru_phi optimization.
2282 int con = value->get_int();
2283 return TypeInt::make((con << 16) >> 16);
2284 }
2285 return LoadNode::Value(phase);
2286 }
2287
2288 //=============================================================================
2289 //----------------------------LoadKlassNode::make------------------------------
2290 // Polymorphic factory method:
2291 Node* LoadKlassNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* at, const TypeKlassPtr* tk) {
2292 // sanity check the alias category against the created node type
2293 const TypePtr *adr_type = adr->bottom_type()->isa_ptr();
2294 assert(adr_type != nullptr, "expecting TypeKlassPtr");
2295 #ifdef _LP64
2296 if (adr_type->is_ptr_to_narrowklass()) {
2297 assert(UseCompressedClassPointers, "no compressed klasses");
2298 Node* load_klass = gvn.transform(new LoadNKlassNode(ctl, mem, adr, at, tk->make_narrowklass(), MemNode::unordered));
2299 return new DecodeNKlassNode(load_klass, load_klass->bottom_type()->make_ptr());
2300 }
2301 #endif
2302 assert(!adr_type->is_ptr_to_narrowklass() && !adr_type->is_ptr_to_narrowoop(), "should have got back a narrow oop");
2303 return new LoadKlassNode(ctl, mem, adr, at, tk, MemNode::unordered);
2304 }
2305
2306 //------------------------------Value------------------------------------------
2307 const Type* LoadKlassNode::Value(PhaseGVN* phase) const {
2308 return klass_value_common(phase);
2309 }
2310
2311 // In most cases, LoadKlassNode does not have the control input set. If the control
2312 // input is set, it must not be removed (by LoadNode::Ideal()).
2313 bool LoadKlassNode::can_remove_control() const {
2314 return false;
2315 }
2316
2317 const Type* LoadNode::klass_value_common(PhaseGVN* phase) const {
2318 // Either input is TOP ==> the result is TOP
2319 const Type *t1 = phase->type( in(MemNode::Memory) );
2320 if (t1 == Type::TOP) return Type::TOP;
2321 Node *adr = in(MemNode::Address);
2322 const Type *t2 = phase->type( adr );
2323 if (t2 == Type::TOP) return Type::TOP;
2324 const TypePtr *tp = t2->is_ptr();
2325 if (TypePtr::above_centerline(tp->ptr()) ||
2326 tp->ptr() == TypePtr::Null) return Type::TOP;
2327
2328 // Return a more precise klass, if possible
2329 const TypeInstPtr *tinst = tp->isa_instptr();
2330 if (tinst != nullptr) {
2331 ciInstanceKlass* ik = tinst->instance_klass();
2332 int offset = tinst->offset();
2333 if (ik == phase->C->env()->Class_klass()
2334 && (offset == java_lang_Class::klass_offset() ||
2335 offset == java_lang_Class::array_klass_offset())) {
2336 // We are loading a special hidden field from a Class mirror object,
2337 // the field which points to the VM's Klass metaobject.
2338 ciType* t = tinst->java_mirror_type();
2339 // java_mirror_type returns non-null for compile-time Class constants.
2340 if (t != nullptr) {
2341 // constant oop => constant klass
2342 if (offset == java_lang_Class::array_klass_offset()) {
2343 if (t->is_void()) {
2344 // We cannot create a void array. Since void is a primitive type return null
2345 // klass. Users of this result need to do a null check on the returned klass.
2346 return TypePtr::NULL_PTR;
2347 }
2348 return TypeKlassPtr::make(ciArrayKlass::make(t), Type::trust_interfaces);
2349 }
2350 if (!t->is_klass()) {
2351 // a primitive Class (e.g., int.class) has null for a klass field
2352 return TypePtr::NULL_PTR;
2353 }
2354 // (Folds up the 1st indirection in aClassConstant.getModifiers().)
2355 return TypeKlassPtr::make(t->as_klass(), Type::trust_interfaces);
2356 }
2357 // non-constant mirror, so we can't tell what's going on
2358 }
2359 if (!tinst->is_loaded())
2360 return _type; // Bail out if not loaded
2361 if (offset == oopDesc::klass_offset_in_bytes()) {
2362 return tinst->as_klass_type(true);
2363 }
2364 }
2365
2366 // Check for loading klass from an array
2367 const TypeAryPtr *tary = tp->isa_aryptr();
2368 if (tary != nullptr &&
2369 tary->offset() == oopDesc::klass_offset_in_bytes()) {
2370 return tary->as_klass_type(true);
2371 }
2372
2373 // Check for loading klass from an array klass
2374 const TypeKlassPtr *tkls = tp->isa_klassptr();
2375 if (tkls != nullptr && !StressReflectiveCode) {
2376 if (!tkls->is_loaded())
2377 return _type; // Bail out if not loaded
2378 if (tkls->isa_aryklassptr() && tkls->is_aryklassptr()->elem()->isa_klassptr() &&
2379 tkls->offset() == in_bytes(ObjArrayKlass::element_klass_offset())) {
2380 // // Always returning precise element type is incorrect,
2381 // // e.g., element type could be object and array may contain strings
2382 // return TypeKlassPtr::make(TypePtr::Constant, elem, 0);
2383
2384 // The array's TypeKlassPtr was declared 'precise' or 'not precise'
2385 // according to the element type's subclassing.
2386 return tkls->is_aryklassptr()->elem()->isa_klassptr()->cast_to_exactness(tkls->klass_is_exact());
2387 }
2388 if (tkls->isa_instklassptr() != nullptr && tkls->klass_is_exact() &&
2389 tkls->offset() == in_bytes(Klass::super_offset())) {
2390 ciKlass* sup = tkls->is_instklassptr()->instance_klass()->super();
2391 // The field is Klass::_super. Return its (constant) value.
2392 // (Folds up the 2nd indirection in aClassConstant.getSuperClass().)
2393 return sup ? TypeKlassPtr::make(sup, Type::trust_interfaces) : TypePtr::NULL_PTR;
2394 }
2395 }
2396
2397 // Bailout case
2398 return LoadNode::Value(phase);
2399 }
2400
2401 //------------------------------Identity---------------------------------------
2402 // To clean up reflective code, simplify k.java_mirror.as_klass to plain k.
2403 // Also feed through the klass in Allocate(...klass...)._klass.
2404 Node* LoadKlassNode::Identity(PhaseGVN* phase) {
2405 return klass_identity_common(phase);
2406 }
2407
2408 Node* LoadNode::klass_identity_common(PhaseGVN* phase) {
2409 Node* x = LoadNode::Identity(phase);
2410 if (x != this) return x;
2411
2412 // Take apart the address into an oop and offset.
2413 // Return 'this' if we cannot.
2414 Node* adr = in(MemNode::Address);
2415 intptr_t offset = 0;
2416 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
2417 if (base == nullptr) return this;
2418 const TypeOopPtr* toop = phase->type(adr)->isa_oopptr();
2419 if (toop == nullptr) return this;
2420
2421 // Step over potential GC barrier for OopHandle resolve
2422 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
2423 if (bs->is_gc_barrier_node(base)) {
2424 base = bs->step_over_gc_barrier(base);
2425 }
2426
2427 // We can fetch the klass directly through an AllocateNode.
2428 // This works even if the klass is not constant (clone or newArray).
2429 if (offset == oopDesc::klass_offset_in_bytes()) {
2430 Node* allocated_klass = AllocateNode::Ideal_klass(base, phase);
2431 if (allocated_klass != nullptr) {
2432 return allocated_klass;
2433 }
2434 }
2435
2436 // Simplify k.java_mirror.as_klass to plain k, where k is a Klass*.
2437 // See inline_native_Class_query for occurrences of these patterns.
2438 // Java Example: x.getClass().isAssignableFrom(y)
2439 //
2440 // This improves reflective code, often making the Class
2441 // mirror go completely dead. (Current exception: Class
2442 // mirrors may appear in debug info, but we could clean them out by
2443 // introducing a new debug info operator for Klass.java_mirror).
2444
2445 if (toop->isa_instptr() && toop->is_instptr()->instance_klass() == phase->C->env()->Class_klass()
2446 && offset == java_lang_Class::klass_offset()) {
2447 if (base->is_Load()) {
2448 Node* base2 = base->in(MemNode::Address);
2449 if (base2->is_Load()) { /* direct load of a load which is the OopHandle */
2450 Node* adr2 = base2->in(MemNode::Address);
2451 const TypeKlassPtr* tkls = phase->type(adr2)->isa_klassptr();
2452 if (tkls != nullptr && !tkls->empty()
2453 && (tkls->isa_instklassptr() || tkls->isa_aryklassptr())
2454 && adr2->is_AddP()
2455 ) {
2456 int mirror_field = in_bytes(Klass::java_mirror_offset());
2457 if (tkls->offset() == mirror_field) {
2458 return adr2->in(AddPNode::Base);
2459 }
2460 }
2461 }
2462 }
2463 }
2464
2465 return this;
2466 }
2467
2468
2469 //------------------------------Value------------------------------------------
2470 const Type* LoadNKlassNode::Value(PhaseGVN* phase) const {
2471 const Type *t = klass_value_common(phase);
2472 if (t == Type::TOP)
2473 return t;
2474
2475 return t->make_narrowklass();
2476 }
2477
2478 //------------------------------Identity---------------------------------------
2479 // To clean up reflective code, simplify k.java_mirror.as_klass to narrow k.
2480 // Also feed through the klass in Allocate(...klass...)._klass.
2481 Node* LoadNKlassNode::Identity(PhaseGVN* phase) {
2482 Node *x = klass_identity_common(phase);
2483
2484 const Type *t = phase->type( x );
2485 if( t == Type::TOP ) return x;
2486 if( t->isa_narrowklass()) return x;
2487 assert (!t->isa_narrowoop(), "no narrow oop here");
2488
2489 return phase->transform(new EncodePKlassNode(x, t->make_narrowklass()));
2490 }
2491
2492 //------------------------------Value-----------------------------------------
2493 const Type* LoadRangeNode::Value(PhaseGVN* phase) const {
2494 // Either input is TOP ==> the result is TOP
2495 const Type *t1 = phase->type( in(MemNode::Memory) );
2496 if( t1 == Type::TOP ) return Type::TOP;
2497 Node *adr = in(MemNode::Address);
2498 const Type *t2 = phase->type( adr );
2499 if( t2 == Type::TOP ) return Type::TOP;
2500 const TypePtr *tp = t2->is_ptr();
2501 if (TypePtr::above_centerline(tp->ptr())) return Type::TOP;
2502 const TypeAryPtr *tap = tp->isa_aryptr();
2503 if( !tap ) return _type;
2504 return tap->size();
2505 }
2506
2507 //-------------------------------Ideal---------------------------------------
2508 // Feed through the length in AllocateArray(...length...)._length.
2509 Node *LoadRangeNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2510 Node* p = MemNode::Ideal_common(phase, can_reshape);
2511 if (p) return (p == NodeSentinel) ? nullptr : p;
2512
2513 // Take apart the address into an oop and offset.
2514 // Return 'this' if we cannot.
2515 Node* adr = in(MemNode::Address);
2516 intptr_t offset = 0;
2517 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
2518 if (base == nullptr) return nullptr;
2519 const TypeAryPtr* tary = phase->type(adr)->isa_aryptr();
2520 if (tary == nullptr) return nullptr;
2521
2522 // We can fetch the length directly through an AllocateArrayNode.
2523 // This works even if the length is not constant (clone or newArray).
2524 if (offset == arrayOopDesc::length_offset_in_bytes()) {
2525 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(base, phase);
2526 if (alloc != nullptr) {
2527 Node* allocated_length = alloc->Ideal_length();
2528 Node* len = alloc->make_ideal_length(tary, phase);
2529 if (allocated_length != len) {
2530 // New CastII improves on this.
2531 return len;
2532 }
2533 }
2534 }
2535
2536 return nullptr;
2537 }
2538
2539 //------------------------------Identity---------------------------------------
2540 // Feed through the length in AllocateArray(...length...)._length.
2541 Node* LoadRangeNode::Identity(PhaseGVN* phase) {
2542 Node* x = LoadINode::Identity(phase);
2543 if (x != this) return x;
2544
2545 // Take apart the address into an oop and offset.
2546 // Return 'this' if we cannot.
2547 Node* adr = in(MemNode::Address);
2548 intptr_t offset = 0;
2549 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
2550 if (base == nullptr) return this;
2551 const TypeAryPtr* tary = phase->type(adr)->isa_aryptr();
2552 if (tary == nullptr) return this;
2553
2554 // We can fetch the length directly through an AllocateArrayNode.
2555 // This works even if the length is not constant (clone or newArray).
2556 if (offset == arrayOopDesc::length_offset_in_bytes()) {
2557 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(base, phase);
2558 if (alloc != nullptr) {
2559 Node* allocated_length = alloc->Ideal_length();
2560 // Do not allow make_ideal_length to allocate a CastII node.
2561 Node* len = alloc->make_ideal_length(tary, phase, false);
2562 if (allocated_length == len) {
2563 // Return allocated_length only if it would not be improved by a CastII.
2564 return allocated_length;
2565 }
2566 }
2567 }
2568
2569 return this;
2570
2571 }
2572
2573 //=============================================================================
2574 //---------------------------StoreNode::make-----------------------------------
2575 // Polymorphic factory method:
2576 StoreNode* StoreNode::make(PhaseGVN& gvn, Node* ctl, Node* mem, Node* adr, const TypePtr* adr_type, Node* val, BasicType bt, MemOrd mo, bool require_atomic_access) {
2577 assert((mo == unordered || mo == release), "unexpected");
2578 Compile* C = gvn.C;
2579 assert(C->get_alias_index(adr_type) != Compile::AliasIdxRaw ||
2580 ctl != nullptr, "raw memory operations should have control edge");
2581
2582 switch (bt) {
2583 case T_BOOLEAN: val = gvn.transform(new AndINode(val, gvn.intcon(0x1))); // Fall through to T_BYTE case
2584 case T_BYTE: return new StoreBNode(ctl, mem, adr, adr_type, val, mo);
2585 case T_INT: return new StoreINode(ctl, mem, adr, adr_type, val, mo);
2586 case T_CHAR:
2587 case T_SHORT: return new StoreCNode(ctl, mem, adr, adr_type, val, mo);
2588 case T_LONG: return new StoreLNode(ctl, mem, adr, adr_type, val, mo, require_atomic_access);
2589 case T_FLOAT: return new StoreFNode(ctl, mem, adr, adr_type, val, mo);
2590 case T_DOUBLE: return new StoreDNode(ctl, mem, adr, adr_type, val, mo, require_atomic_access);
2591 case T_METADATA:
2592 case T_ADDRESS:
2593 case T_OBJECT:
2594 #ifdef _LP64
2595 if (adr->bottom_type()->is_ptr_to_narrowoop()) {
2596 val = gvn.transform(new EncodePNode(val, val->bottom_type()->make_narrowoop()));
2597 return new StoreNNode(ctl, mem, adr, adr_type, val, mo);
2598 } else if (adr->bottom_type()->is_ptr_to_narrowklass() ||
2599 (UseCompressedClassPointers && val->bottom_type()->isa_klassptr() &&
2600 adr->bottom_type()->isa_rawptr())) {
2601 val = gvn.transform(new EncodePKlassNode(val, val->bottom_type()->make_narrowklass()));
2602 return new StoreNKlassNode(ctl, mem, adr, adr_type, val, mo);
2603 }
2604 #endif
2605 {
2606 return new StorePNode(ctl, mem, adr, adr_type, val, mo);
2607 }
2608 default:
2609 ShouldNotReachHere();
2610 return (StoreNode*)nullptr;
2611 }
2612 }
2613
2614 //--------------------------bottom_type----------------------------------------
2615 const Type *StoreNode::bottom_type() const {
2616 return Type::MEMORY;
2617 }
2618
2619 //------------------------------hash-------------------------------------------
2620 uint StoreNode::hash() const {
2621 // unroll addition of interesting fields
2622 //return (uintptr_t)in(Control) + (uintptr_t)in(Memory) + (uintptr_t)in(Address) + (uintptr_t)in(ValueIn);
2623
2624 // Since they are not commoned, do not hash them:
2625 return NO_HASH;
2626 }
2627
2628 //------------------------------Ideal------------------------------------------
2629 // Change back-to-back Store(, p, x) -> Store(m, p, y) to Store(m, p, x).
2630 // When a store immediately follows a relevant allocation/initialization,
2631 // try to capture it into the initialization, or hoist it above.
2632 Node *StoreNode::Ideal(PhaseGVN *phase, bool can_reshape) {
2633 Node* p = MemNode::Ideal_common(phase, can_reshape);
2634 if (p) return (p == NodeSentinel) ? nullptr : p;
2635
2636 Node* mem = in(MemNode::Memory);
2637 Node* address = in(MemNode::Address);
2638 Node* value = in(MemNode::ValueIn);
2639 // Back-to-back stores to same address? Fold em up. Generally
2640 // unsafe if I have intervening uses... Also disallowed for StoreCM
2641 // since they must follow each StoreP operation. Redundant StoreCMs
2642 // are eliminated just before matching in final_graph_reshape.
2643 {
2644 Node* st = mem;
2645 // If Store 'st' has more than one use, we cannot fold 'st' away.
2646 // For example, 'st' might be the final state at a conditional
2647 // return. Or, 'st' might be used by some node which is live at
2648 // the same time 'st' is live, which might be unschedulable. So,
2649 // require exactly ONE user until such time as we clone 'mem' for
2650 // each of 'mem's uses (thus making the exactly-1-user-rule hold
2651 // true).
2652 while (st->is_Store() && st->outcnt() == 1 && st->Opcode() != Op_StoreCM) {
2653 // Looking at a dead closed cycle of memory?
2654 assert(st != st->in(MemNode::Memory), "dead loop in StoreNode::Ideal");
2655 assert(Opcode() == st->Opcode() ||
2656 st->Opcode() == Op_StoreVector ||
2657 Opcode() == Op_StoreVector ||
2658 st->Opcode() == Op_StoreVectorScatter ||
2659 Opcode() == Op_StoreVectorScatter ||
2660 phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw ||
2661 (Opcode() == Op_StoreL && st->Opcode() == Op_StoreI) || // expanded ClearArrayNode
2662 (Opcode() == Op_StoreI && st->Opcode() == Op_StoreL) || // initialization by arraycopy
2663 (is_mismatched_access() || st->as_Store()->is_mismatched_access()),
2664 "no mismatched stores, except on raw memory: %s %s", NodeClassNames[Opcode()], NodeClassNames[st->Opcode()]);
2665
2666 if (st->in(MemNode::Address)->eqv_uncast(address) &&
2667 st->as_Store()->memory_size() <= this->memory_size()) {
2668 Node* use = st->raw_out(0);
2669 if (phase->is_IterGVN()) {
2670 phase->is_IterGVN()->rehash_node_delayed(use);
2671 }
2672 // It's OK to do this in the parser, since DU info is always accurate,
2673 // and the parser always refers to nodes via SafePointNode maps.
2674 use->set_req_X(MemNode::Memory, st->in(MemNode::Memory), phase);
2675 return this;
2676 }
2677 st = st->in(MemNode::Memory);
2678 }
2679 }
2680
2681
2682 // Capture an unaliased, unconditional, simple store into an initializer.
2683 // Or, if it is independent of the allocation, hoist it above the allocation.
2684 if (ReduceFieldZeroing && /*can_reshape &&*/
2685 mem->is_Proj() && mem->in(0)->is_Initialize()) {
2686 InitializeNode* init = mem->in(0)->as_Initialize();
2687 intptr_t offset = init->can_capture_store(this, phase, can_reshape);
2688 if (offset > 0) {
2689 Node* moved = init->capture_store(this, offset, phase, can_reshape);
2690 // If the InitializeNode captured me, it made a raw copy of me,
2691 // and I need to disappear.
2692 if (moved != nullptr) {
2693 // %%% hack to ensure that Ideal returns a new node:
2694 mem = MergeMemNode::make(mem);
2695 return mem; // fold me away
2696 }
2697 }
2698 }
2699
2700 // Fold reinterpret cast into memory operation:
2701 // StoreX mem (MoveY2X v) => StoreY mem v
2702 if (value->is_Move()) {
2703 const Type* vt = value->in(1)->bottom_type();
2704 if (has_reinterpret_variant(vt)) {
2705 if (phase->C->post_loop_opts_phase()) {
2706 return convert_to_reinterpret_store(*phase, value->in(1), vt);
2707 } else {
2708 phase->C->record_for_post_loop_opts_igvn(this); // attempt the transformation once loop opts are over
2709 }
2710 }
2711 }
2712
2713 return nullptr; // No further progress
2714 }
2715
2716 //------------------------------Value-----------------------------------------
2717 const Type* StoreNode::Value(PhaseGVN* phase) const {
2718 // Either input is TOP ==> the result is TOP
2719 const Type *t1 = phase->type( in(MemNode::Memory) );
2720 if( t1 == Type::TOP ) return Type::TOP;
2721 const Type *t2 = phase->type( in(MemNode::Address) );
2722 if( t2 == Type::TOP ) return Type::TOP;
2723 const Type *t3 = phase->type( in(MemNode::ValueIn) );
2724 if( t3 == Type::TOP ) return Type::TOP;
2725 return Type::MEMORY;
2726 }
2727
2728 //------------------------------Identity---------------------------------------
2729 // Remove redundant stores:
2730 // Store(m, p, Load(m, p)) changes to m.
2731 // Store(, p, x) -> Store(m, p, x) changes to Store(m, p, x).
2732 Node* StoreNode::Identity(PhaseGVN* phase) {
2733 Node* mem = in(MemNode::Memory);
2734 Node* adr = in(MemNode::Address);
2735 Node* val = in(MemNode::ValueIn);
2736
2737 Node* result = this;
2738
2739 // Load then Store? Then the Store is useless
2740 if (val->is_Load() &&
2741 val->in(MemNode::Address)->eqv_uncast(adr) &&
2742 val->in(MemNode::Memory )->eqv_uncast(mem) &&
2743 val->as_Load()->store_Opcode() == Opcode()) {
2744 result = mem;
2745 }
2746
2747 // Two stores in a row of the same value?
2748 if (result == this &&
2749 mem->is_Store() &&
2750 mem->in(MemNode::Address)->eqv_uncast(adr) &&
2751 mem->in(MemNode::ValueIn)->eqv_uncast(val) &&
2752 mem->Opcode() == Opcode()) {
2753 result = mem;
2754 }
2755
2756 // Store of zero anywhere into a freshly-allocated object?
2757 // Then the store is useless.
2758 // (It must already have been captured by the InitializeNode.)
2759 if (result == this &&
2760 ReduceFieldZeroing && phase->type(val)->is_zero_type()) {
2761 // a newly allocated object is already all-zeroes everywhere
2762 if (mem->is_Proj() && mem->in(0)->is_Allocate()) {
2763 result = mem;
2764 }
2765
2766 if (result == this) {
2767 // the store may also apply to zero-bits in an earlier object
2768 Node* prev_mem = find_previous_store(phase);
2769 // Steps (a), (b): Walk past independent stores to find an exact match.
2770 if (prev_mem != nullptr) {
2771 Node* prev_val = can_see_stored_value(prev_mem, phase);
2772 if (prev_val != nullptr && prev_val == val) {
2773 // prev_val and val might differ by a cast; it would be good
2774 // to keep the more informative of the two.
2775 result = mem;
2776 }
2777 }
2778 }
2779 }
2780
2781 PhaseIterGVN* igvn = phase->is_IterGVN();
2782 if (result != this && igvn != nullptr) {
2783 MemBarNode* trailing = trailing_membar();
2784 if (trailing != nullptr) {
2785 #ifdef ASSERT
2786 const TypeOopPtr* t_oop = phase->type(in(Address))->isa_oopptr();
2787 assert(t_oop == nullptr || t_oop->is_known_instance_field(), "only for non escaping objects");
2788 #endif
2789 trailing->remove(igvn);
2790 }
2791 }
2792
2793 return result;
2794 }
2795
2796 //------------------------------match_edge-------------------------------------
2797 // Do we Match on this edge index or not? Match only memory & value
2798 uint StoreNode::match_edge(uint idx) const {
2799 return idx == MemNode::Address || idx == MemNode::ValueIn;
2800 }
2801
2802 //------------------------------cmp--------------------------------------------
2803 // Do not common stores up together. They generally have to be split
2804 // back up anyways, so do not bother.
2805 bool StoreNode::cmp( const Node &n ) const {
2806 return (&n == this); // Always fail except on self
2807 }
2808
2809 //------------------------------Ideal_masked_input-----------------------------
2810 // Check for a useless mask before a partial-word store
2811 // (StoreB ... (AndI valIn conIa) )
2812 // If (conIa & mask == mask) this simplifies to
2813 // (StoreB ... (valIn) )
2814 Node *StoreNode::Ideal_masked_input(PhaseGVN *phase, uint mask) {
2815 Node *val = in(MemNode::ValueIn);
2816 if( val->Opcode() == Op_AndI ) {
2817 const TypeInt *t = phase->type( val->in(2) )->isa_int();
2818 if( t && t->is_con() && (t->get_con() & mask) == mask ) {
2819 set_req_X(MemNode::ValueIn, val->in(1), phase);
2820 return this;
2821 }
2822 }
2823 return nullptr;
2824 }
2825
2826
2827 //------------------------------Ideal_sign_extended_input----------------------
2828 // Check for useless sign-extension before a partial-word store
2829 // (StoreB ... (RShiftI _ (LShiftI _ valIn conIL ) conIR) )
2830 // If (conIL == conIR && conIR <= num_bits) this simplifies to
2831 // (StoreB ... (valIn) )
2832 Node *StoreNode::Ideal_sign_extended_input(PhaseGVN *phase, int num_bits) {
2833 Node *val = in(MemNode::ValueIn);
2834 if( val->Opcode() == Op_RShiftI ) {
2835 const TypeInt *t = phase->type( val->in(2) )->isa_int();
2836 if( t && t->is_con() && (t->get_con() <= num_bits) ) {
2837 Node *shl = val->in(1);
2838 if( shl->Opcode() == Op_LShiftI ) {
2839 const TypeInt *t2 = phase->type( shl->in(2) )->isa_int();
2840 if( t2 && t2->is_con() && (t2->get_con() == t->get_con()) ) {
2841 set_req_X(MemNode::ValueIn, shl->in(1), phase);
2842 return this;
2843 }
2844 }
2845 }
2846 }
2847 return nullptr;
2848 }
2849
2850 //------------------------------value_never_loaded-----------------------------------
2851 // Determine whether there are any possible loads of the value stored.
2852 // For simplicity, we actually check if there are any loads from the
2853 // address stored to, not just for loads of the value stored by this node.
2854 //
2855 bool StoreNode::value_never_loaded(PhaseValues* phase) const {
2856 Node *adr = in(Address);
2857 const TypeOopPtr *adr_oop = phase->type(adr)->isa_oopptr();
2858 if (adr_oop == nullptr)
2859 return false;
2860 if (!adr_oop->is_known_instance_field())
2861 return false; // if not a distinct instance, there may be aliases of the address
2862 for (DUIterator_Fast imax, i = adr->fast_outs(imax); i < imax; i++) {
2863 Node *use = adr->fast_out(i);
2864 if (use->is_Load() || use->is_LoadStore()) {
2865 return false;
2866 }
2867 }
2868 return true;
2869 }
2870
2871 MemBarNode* StoreNode::trailing_membar() const {
2872 if (is_release()) {
2873 MemBarNode* trailing_mb = nullptr;
2874 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
2875 Node* u = fast_out(i);
2876 if (u->is_MemBar()) {
2877 if (u->as_MemBar()->trailing_store()) {
2878 assert(u->Opcode() == Op_MemBarVolatile, "");
2879 assert(trailing_mb == nullptr, "only one");
2880 trailing_mb = u->as_MemBar();
2881 #ifdef ASSERT
2882 Node* leading = u->as_MemBar()->leading_membar();
2883 assert(leading->Opcode() == Op_MemBarRelease, "incorrect membar");
2884 assert(leading->as_MemBar()->leading_store(), "incorrect membar pair");
2885 assert(leading->as_MemBar()->trailing_membar() == u, "incorrect membar pair");
2886 #endif
2887 } else {
2888 assert(u->as_MemBar()->standalone(), "");
2889 }
2890 }
2891 }
2892 return trailing_mb;
2893 }
2894 return nullptr;
2895 }
2896
2897
2898 //=============================================================================
2899 //------------------------------Ideal------------------------------------------
2900 // If the store is from an AND mask that leaves the low bits untouched, then
2901 // we can skip the AND operation. If the store is from a sign-extension
2902 // (a left shift, then right shift) we can skip both.
2903 Node *StoreBNode::Ideal(PhaseGVN *phase, bool can_reshape){
2904 Node *progress = StoreNode::Ideal_masked_input(phase, 0xFF);
2905 if( progress != nullptr ) return progress;
2906
2907 progress = StoreNode::Ideal_sign_extended_input(phase, 24);
2908 if( progress != nullptr ) return progress;
2909
2910 // Finally check the default case
2911 return StoreNode::Ideal(phase, can_reshape);
2912 }
2913
2914 //=============================================================================
2915 //------------------------------Ideal------------------------------------------
2916 // If the store is from an AND mask that leaves the low bits untouched, then
2917 // we can skip the AND operation
2918 Node *StoreCNode::Ideal(PhaseGVN *phase, bool can_reshape){
2919 Node *progress = StoreNode::Ideal_masked_input(phase, 0xFFFF);
2920 if( progress != nullptr ) return progress;
2921
2922 progress = StoreNode::Ideal_sign_extended_input(phase, 16);
2923 if( progress != nullptr ) return progress;
2924
2925 // Finally check the default case
2926 return StoreNode::Ideal(phase, can_reshape);
2927 }
2928
2929 //=============================================================================
2930 //------------------------------Identity---------------------------------------
2931 Node* StoreCMNode::Identity(PhaseGVN* phase) {
2932 // No need to card mark when storing a null ptr
2933 Node* my_store = in(MemNode::OopStore);
2934 if (my_store->is_Store()) {
2935 const Type *t1 = phase->type( my_store->in(MemNode::ValueIn) );
2936 if( t1 == TypePtr::NULL_PTR ) {
2937 return in(MemNode::Memory);
2938 }
2939 }
2940 return this;
2941 }
2942
2943 //=============================================================================
2944 //------------------------------Ideal---------------------------------------
2945 Node *StoreCMNode::Ideal(PhaseGVN *phase, bool can_reshape){
2946 Node* progress = StoreNode::Ideal(phase, can_reshape);
2947 if (progress != nullptr) return progress;
2948
2949 Node* my_store = in(MemNode::OopStore);
2950 if (my_store->is_MergeMem()) {
2951 Node* mem = my_store->as_MergeMem()->memory_at(oop_alias_idx());
2952 set_req_X(MemNode::OopStore, mem, phase);
2953 return this;
2954 }
2955
2956 return nullptr;
2957 }
2958
2959 //------------------------------Value-----------------------------------------
2960 const Type* StoreCMNode::Value(PhaseGVN* phase) const {
2961 // Either input is TOP ==> the result is TOP (checked in StoreNode::Value).
2962 // If extra input is TOP ==> the result is TOP
2963 const Type* t = phase->type(in(MemNode::OopStore));
2964 if (t == Type::TOP) {
2965 return Type::TOP;
2966 }
2967 return StoreNode::Value(phase);
2968 }
2969
2970
2971 //=============================================================================
2972 //----------------------------------SCMemProjNode------------------------------
2973 const Type* SCMemProjNode::Value(PhaseGVN* phase) const
2974 {
2975 if (in(0) == nullptr || phase->type(in(0)) == Type::TOP) {
2976 return Type::TOP;
2977 }
2978 return bottom_type();
2979 }
2980
2981 //=============================================================================
2982 //----------------------------------LoadStoreNode------------------------------
2983 LoadStoreNode::LoadStoreNode( Node *c, Node *mem, Node *adr, Node *val, const TypePtr* at, const Type* rt, uint required )
2984 : Node(required),
2985 _type(rt),
2986 _adr_type(at),
2987 _barrier_data(0)
2988 {
2989 init_req(MemNode::Control, c );
2990 init_req(MemNode::Memory , mem);
2991 init_req(MemNode::Address, adr);
2992 init_req(MemNode::ValueIn, val);
2993 init_class_id(Class_LoadStore);
2994 }
2995
2996 //------------------------------Value-----------------------------------------
2997 const Type* LoadStoreNode::Value(PhaseGVN* phase) const {
2998 // Either input is TOP ==> the result is TOP
2999 if (!in(MemNode::Control) || phase->type(in(MemNode::Control)) == Type::TOP) {
3000 return Type::TOP;
3001 }
3002 const Type* t = phase->type(in(MemNode::Memory));
3003 if (t == Type::TOP) {
3004 return Type::TOP;
3005 }
3006 t = phase->type(in(MemNode::Address));
3007 if (t == Type::TOP) {
3008 return Type::TOP;
3009 }
3010 t = phase->type(in(MemNode::ValueIn));
3011 if (t == Type::TOP) {
3012 return Type::TOP;
3013 }
3014 return bottom_type();
3015 }
3016
3017 uint LoadStoreNode::ideal_reg() const {
3018 return _type->ideal_reg();
3019 }
3020
3021 bool LoadStoreNode::result_not_used() const {
3022 for( DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++ ) {
3023 Node *x = fast_out(i);
3024 if (x->Opcode() == Op_SCMemProj) continue;
3025 return false;
3026 }
3027 return true;
3028 }
3029
3030 MemBarNode* LoadStoreNode::trailing_membar() const {
3031 MemBarNode* trailing = nullptr;
3032 for (DUIterator_Fast imax, i = fast_outs(imax); i < imax; i++) {
3033 Node* u = fast_out(i);
3034 if (u->is_MemBar()) {
3035 if (u->as_MemBar()->trailing_load_store()) {
3036 assert(u->Opcode() == Op_MemBarAcquire, "");
3037 assert(trailing == nullptr, "only one");
3038 trailing = u->as_MemBar();
3039 #ifdef ASSERT
3040 Node* leading = trailing->leading_membar();
3041 assert(support_IRIW_for_not_multiple_copy_atomic_cpu || leading->Opcode() == Op_MemBarRelease, "incorrect membar");
3042 assert(leading->as_MemBar()->leading_load_store(), "incorrect membar pair");
3043 assert(leading->as_MemBar()->trailing_membar() == trailing, "incorrect membar pair");
3044 #endif
3045 } else {
3046 assert(u->as_MemBar()->standalone(), "wrong barrier kind");
3047 }
3048 }
3049 }
3050
3051 return trailing;
3052 }
3053
3054 uint LoadStoreNode::size_of() const { return sizeof(*this); }
3055
3056 //=============================================================================
3057 //----------------------------------LoadStoreConditionalNode--------------------
3058 LoadStoreConditionalNode::LoadStoreConditionalNode( Node *c, Node *mem, Node *adr, Node *val, Node *ex ) : LoadStoreNode(c, mem, adr, val, nullptr, TypeInt::BOOL, 5) {
3059 init_req(ExpectedIn, ex );
3060 }
3061
3062 const Type* LoadStoreConditionalNode::Value(PhaseGVN* phase) const {
3063 // Either input is TOP ==> the result is TOP
3064 const Type* t = phase->type(in(ExpectedIn));
3065 if (t == Type::TOP) {
3066 return Type::TOP;
3067 }
3068 return LoadStoreNode::Value(phase);
3069 }
3070
3071 //=============================================================================
3072 //-------------------------------adr_type--------------------------------------
3073 const TypePtr* ClearArrayNode::adr_type() const {
3074 Node *adr = in(3);
3075 if (adr == nullptr) return nullptr; // node is dead
3076 return MemNode::calculate_adr_type(adr->bottom_type());
3077 }
3078
3079 //------------------------------match_edge-------------------------------------
3080 // Do we Match on this edge index or not? Do not match memory
3081 uint ClearArrayNode::match_edge(uint idx) const {
3082 return idx > 1;
3083 }
3084
3085 //------------------------------Identity---------------------------------------
3086 // Clearing a zero length array does nothing
3087 Node* ClearArrayNode::Identity(PhaseGVN* phase) {
3088 return phase->type(in(2))->higher_equal(TypeX::ZERO) ? in(1) : this;
3089 }
3090
3091 //------------------------------Idealize---------------------------------------
3092 // Clearing a short array is faster with stores
3093 Node *ClearArrayNode::Ideal(PhaseGVN *phase, bool can_reshape) {
3094 // Already know this is a large node, do not try to ideal it
3095 if (_is_large) return nullptr;
3096
3097 const int unit = BytesPerLong;
3098 const TypeX* t = phase->type(in(2))->isa_intptr_t();
3099 if (!t) return nullptr;
3100 if (!t->is_con()) return nullptr;
3101 intptr_t raw_count = t->get_con();
3102 intptr_t size = raw_count;
3103 if (!Matcher::init_array_count_is_in_bytes) size *= unit;
3104 // Clearing nothing uses the Identity call.
3105 // Negative clears are possible on dead ClearArrays
3106 // (see jck test stmt114.stmt11402.val).
3107 if (size <= 0 || size % unit != 0) return nullptr;
3108 intptr_t count = size / unit;
3109 // Length too long; communicate this to matchers and assemblers.
3110 // Assemblers are responsible to produce fast hardware clears for it.
3111 if (size > InitArrayShortSize) {
3112 return new ClearArrayNode(in(0), in(1), in(2), in(3), true);
3113 } else if (size > 2 && Matcher::match_rule_supported_vector(Op_ClearArray, 4, T_LONG)) {
3114 return nullptr;
3115 }
3116 if (!IdealizeClearArrayNode) return nullptr;
3117 Node *mem = in(1);
3118 if( phase->type(mem)==Type::TOP ) return nullptr;
3119 Node *adr = in(3);
3120 const Type* at = phase->type(adr);
3121 if( at==Type::TOP ) return nullptr;
3122 const TypePtr* atp = at->isa_ptr();
3123 // adjust atp to be the correct array element address type
3124 if (atp == nullptr) atp = TypePtr::BOTTOM;
3125 else atp = atp->add_offset(Type::OffsetBot);
3126 // Get base for derived pointer purposes
3127 if( adr->Opcode() != Op_AddP ) Unimplemented();
3128 Node *base = adr->in(1);
3129
3130 Node *zero = phase->makecon(TypeLong::ZERO);
3131 Node *off = phase->MakeConX(BytesPerLong);
3132 mem = new StoreLNode(in(0),mem,adr,atp,zero,MemNode::unordered,false);
3133 count--;
3134 while( count-- ) {
3135 mem = phase->transform(mem);
3136 adr = phase->transform(new AddPNode(base,adr,off));
3137 mem = new StoreLNode(in(0),mem,adr,atp,zero,MemNode::unordered,false);
3138 }
3139 return mem;
3140 }
3141
3142 //----------------------------step_through----------------------------------
3143 // Return allocation input memory edge if it is different instance
3144 // or itself if it is the one we are looking for.
3145 bool ClearArrayNode::step_through(Node** np, uint instance_id, PhaseValues* phase) {
3146 Node* n = *np;
3147 assert(n->is_ClearArray(), "sanity");
3148 intptr_t offset;
3149 AllocateNode* alloc = AllocateNode::Ideal_allocation(n->in(3), phase, offset);
3150 // This method is called only before Allocate nodes are expanded
3151 // during macro nodes expansion. Before that ClearArray nodes are
3152 // only generated in PhaseMacroExpand::generate_arraycopy() (before
3153 // Allocate nodes are expanded) which follows allocations.
3154 assert(alloc != nullptr, "should have allocation");
3155 if (alloc->_idx == instance_id) {
3156 // Can not bypass initialization of the instance we are looking for.
3157 return false;
3158 }
3159 // Otherwise skip it.
3160 InitializeNode* init = alloc->initialization();
3161 if (init != nullptr)
3162 *np = init->in(TypeFunc::Memory);
3163 else
3164 *np = alloc->in(TypeFunc::Memory);
3165 return true;
3166 }
3167
3168 //----------------------------clear_memory-------------------------------------
3169 // Generate code to initialize object storage to zero.
3170 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
3171 intptr_t start_offset,
3172 Node* end_offset,
3173 PhaseGVN* phase) {
3174 intptr_t offset = start_offset;
3175
3176 int unit = BytesPerLong;
3177 if ((offset % unit) != 0) {
3178 Node* adr = new AddPNode(dest, dest, phase->MakeConX(offset));
3179 adr = phase->transform(adr);
3180 const TypePtr* atp = TypeRawPtr::BOTTOM;
3181 mem = StoreNode::make(*phase, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT, MemNode::unordered);
3182 mem = phase->transform(mem);
3183 offset += BytesPerInt;
3184 }
3185 assert((offset % unit) == 0, "");
3186
3187 // Initialize the remaining stuff, if any, with a ClearArray.
3188 return clear_memory(ctl, mem, dest, phase->MakeConX(offset), end_offset, phase);
3189 }
3190
3191 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
3192 Node* start_offset,
3193 Node* end_offset,
3194 PhaseGVN* phase) {
3195 if (start_offset == end_offset) {
3196 // nothing to do
3197 return mem;
3198 }
3199
3200 int unit = BytesPerLong;
3201 Node* zbase = start_offset;
3202 Node* zend = end_offset;
3203
3204 // Scale to the unit required by the CPU:
3205 if (!Matcher::init_array_count_is_in_bytes) {
3206 Node* shift = phase->intcon(exact_log2(unit));
3207 zbase = phase->transform(new URShiftXNode(zbase, shift) );
3208 zend = phase->transform(new URShiftXNode(zend, shift) );
3209 }
3210
3211 // Bulk clear double-words
3212 Node* zsize = phase->transform(new SubXNode(zend, zbase) );
3213 Node* adr = phase->transform(new AddPNode(dest, dest, start_offset) );
3214 mem = new ClearArrayNode(ctl, mem, zsize, adr, false);
3215 return phase->transform(mem);
3216 }
3217
3218 Node* ClearArrayNode::clear_memory(Node* ctl, Node* mem, Node* dest,
3219 intptr_t start_offset,
3220 intptr_t end_offset,
3221 PhaseGVN* phase) {
3222 if (start_offset == end_offset) {
3223 // nothing to do
3224 return mem;
3225 }
3226
3227 assert((end_offset % BytesPerInt) == 0, "odd end offset");
3228 intptr_t done_offset = end_offset;
3229 if ((done_offset % BytesPerLong) != 0) {
3230 done_offset -= BytesPerInt;
3231 }
3232 if (done_offset > start_offset) {
3233 mem = clear_memory(ctl, mem, dest,
3234 start_offset, phase->MakeConX(done_offset), phase);
3235 }
3236 if (done_offset < end_offset) { // emit the final 32-bit store
3237 Node* adr = new AddPNode(dest, dest, phase->MakeConX(done_offset));
3238 adr = phase->transform(adr);
3239 const TypePtr* atp = TypeRawPtr::BOTTOM;
3240 mem = StoreNode::make(*phase, ctl, mem, adr, atp, phase->zerocon(T_INT), T_INT, MemNode::unordered);
3241 mem = phase->transform(mem);
3242 done_offset += BytesPerInt;
3243 }
3244 assert(done_offset == end_offset, "");
3245 return mem;
3246 }
3247
3248 //=============================================================================
3249 MemBarNode::MemBarNode(Compile* C, int alias_idx, Node* precedent)
3250 : MultiNode(TypeFunc::Parms + (precedent == nullptr? 0: 1)),
3251 _adr_type(C->get_adr_type(alias_idx)), _kind(Standalone)
3252 #ifdef ASSERT
3253 , _pair_idx(0)
3254 #endif
3255 {
3256 init_class_id(Class_MemBar);
3257 Node* top = C->top();
3258 init_req(TypeFunc::I_O,top);
3259 init_req(TypeFunc::FramePtr,top);
3260 init_req(TypeFunc::ReturnAdr,top);
3261 if (precedent != nullptr)
3262 init_req(TypeFunc::Parms, precedent);
3263 }
3264
3265 //------------------------------cmp--------------------------------------------
3266 uint MemBarNode::hash() const { return NO_HASH; }
3267 bool MemBarNode::cmp( const Node &n ) const {
3268 return (&n == this); // Always fail except on self
3269 }
3270
3271 //------------------------------make-------------------------------------------
3272 MemBarNode* MemBarNode::make(Compile* C, int opcode, int atp, Node* pn) {
3273 switch (opcode) {
3274 case Op_MemBarAcquire: return new MemBarAcquireNode(C, atp, pn);
3275 case Op_LoadFence: return new LoadFenceNode(C, atp, pn);
3276 case Op_MemBarRelease: return new MemBarReleaseNode(C, atp, pn);
3277 case Op_StoreFence: return new StoreFenceNode(C, atp, pn);
3278 case Op_MemBarStoreStore: return new MemBarStoreStoreNode(C, atp, pn);
3279 case Op_StoreStoreFence: return new StoreStoreFenceNode(C, atp, pn);
3280 case Op_MemBarAcquireLock: return new MemBarAcquireLockNode(C, atp, pn);
3281 case Op_MemBarReleaseLock: return new MemBarReleaseLockNode(C, atp, pn);
3282 case Op_MemBarVolatile: return new MemBarVolatileNode(C, atp, pn);
3283 case Op_MemBarCPUOrder: return new MemBarCPUOrderNode(C, atp, pn);
3284 case Op_OnSpinWait: return new OnSpinWaitNode(C, atp, pn);
3285 case Op_Initialize: return new InitializeNode(C, atp, pn);
3286 default: ShouldNotReachHere(); return nullptr;
3287 }
3288 }
3289
3290 void MemBarNode::remove(PhaseIterGVN *igvn) {
3291 if (outcnt() != 2) {
3292 assert(Opcode() == Op_Initialize, "Only seen when there are no use of init memory");
3293 assert(outcnt() == 1, "Only control then");
3294 }
3295 if (trailing_store() || trailing_load_store()) {
3296 MemBarNode* leading = leading_membar();
3297 if (leading != nullptr) {
3298 assert(leading->trailing_membar() == this, "inconsistent leading/trailing membars");
3299 leading->remove(igvn);
3300 }
3301 }
3302 if (proj_out_or_null(TypeFunc::Memory) != nullptr) {
3303 igvn->replace_node(proj_out(TypeFunc::Memory), in(TypeFunc::Memory));
3304 }
3305 if (proj_out_or_null(TypeFunc::Control) != nullptr) {
3306 igvn->replace_node(proj_out(TypeFunc::Control), in(TypeFunc::Control));
3307 }
3308 }
3309
3310 //------------------------------Ideal------------------------------------------
3311 // Return a node which is more "ideal" than the current node. Strip out
3312 // control copies
3313 Node *MemBarNode::Ideal(PhaseGVN *phase, bool can_reshape) {
3314 if (remove_dead_region(phase, can_reshape)) return this;
3315 // Don't bother trying to transform a dead node
3316 if (in(0) && in(0)->is_top()) {
3317 return nullptr;
3318 }
3319
3320 bool progress = false;
3321 // Eliminate volatile MemBars for scalar replaced objects.
3322 if (can_reshape && req() == (Precedent+1)) {
3323 bool eliminate = false;
3324 int opc = Opcode();
3325 if ((opc == Op_MemBarAcquire || opc == Op_MemBarVolatile)) {
3326 // Volatile field loads and stores.
3327 Node* my_mem = in(MemBarNode::Precedent);
3328 // The MembarAquire may keep an unused LoadNode alive through the Precedent edge
3329 if ((my_mem != nullptr) && (opc == Op_MemBarAcquire) && (my_mem->outcnt() == 1)) {
3330 // if the Precedent is a decodeN and its input (a Load) is used at more than one place,
3331 // replace this Precedent (decodeN) with the Load instead.
3332 if ((my_mem->Opcode() == Op_DecodeN) && (my_mem->in(1)->outcnt() > 1)) {
3333 Node* load_node = my_mem->in(1);
3334 set_req(MemBarNode::Precedent, load_node);
3335 phase->is_IterGVN()->_worklist.push(my_mem);
3336 my_mem = load_node;
3337 } else {
3338 assert(my_mem->unique_out() == this, "sanity");
3339 del_req(Precedent);
3340 phase->is_IterGVN()->_worklist.push(my_mem); // remove dead node later
3341 my_mem = nullptr;
3342 }
3343 progress = true;
3344 }
3345 if (my_mem != nullptr && my_mem->is_Mem()) {
3346 const TypeOopPtr* t_oop = my_mem->in(MemNode::Address)->bottom_type()->isa_oopptr();
3347 // Check for scalar replaced object reference.
3348 if( t_oop != nullptr && t_oop->is_known_instance_field() &&
3349 t_oop->offset() != Type::OffsetBot &&
3350 t_oop->offset() != Type::OffsetTop) {
3351 eliminate = true;
3352 }
3353 }
3354 } else if (opc == Op_MemBarRelease) {
3355 // Final field stores.
3356 Node* alloc = AllocateNode::Ideal_allocation(in(MemBarNode::Precedent), phase);
3357 if ((alloc != nullptr) && alloc->is_Allocate() &&
3358 alloc->as_Allocate()->does_not_escape_thread()) {
3359 // The allocated object does not escape.
3360 eliminate = true;
3361 }
3362 }
3363 if (eliminate) {
3364 // Replace MemBar projections by its inputs.
3365 PhaseIterGVN* igvn = phase->is_IterGVN();
3366 remove(igvn);
3367 // Must return either the original node (now dead) or a new node
3368 // (Do not return a top here, since that would break the uniqueness of top.)
3369 return new ConINode(TypeInt::ZERO);
3370 }
3371 }
3372 return progress ? this : nullptr;
3373 }
3374
3375 //------------------------------Value------------------------------------------
3376 const Type* MemBarNode::Value(PhaseGVN* phase) const {
3377 if( !in(0) ) return Type::TOP;
3378 if( phase->type(in(0)) == Type::TOP )
3379 return Type::TOP;
3380 return TypeTuple::MEMBAR;
3381 }
3382
3383 //------------------------------match------------------------------------------
3384 // Construct projections for memory.
3385 Node *MemBarNode::match( const ProjNode *proj, const Matcher *m ) {
3386 switch (proj->_con) {
3387 case TypeFunc::Control:
3388 case TypeFunc::Memory:
3389 return new MachProjNode(this,proj->_con,RegMask::Empty,MachProjNode::unmatched_proj);
3390 }
3391 ShouldNotReachHere();
3392 return nullptr;
3393 }
3394
3395 void MemBarNode::set_store_pair(MemBarNode* leading, MemBarNode* trailing) {
3396 trailing->_kind = TrailingStore;
3397 leading->_kind = LeadingStore;
3398 #ifdef ASSERT
3399 trailing->_pair_idx = leading->_idx;
3400 leading->_pair_idx = leading->_idx;
3401 #endif
3402 }
3403
3404 void MemBarNode::set_load_store_pair(MemBarNode* leading, MemBarNode* trailing) {
3405 trailing->_kind = TrailingLoadStore;
3406 leading->_kind = LeadingLoadStore;
3407 #ifdef ASSERT
3408 trailing->_pair_idx = leading->_idx;
3409 leading->_pair_idx = leading->_idx;
3410 #endif
3411 }
3412
3413 MemBarNode* MemBarNode::trailing_membar() const {
3414 ResourceMark rm;
3415 Node* trailing = (Node*)this;
3416 VectorSet seen;
3417 Node_Stack multis(0);
3418 do {
3419 Node* c = trailing;
3420 uint i = 0;
3421 do {
3422 trailing = nullptr;
3423 for (; i < c->outcnt(); i++) {
3424 Node* next = c->raw_out(i);
3425 if (next != c && next->is_CFG()) {
3426 if (c->is_MultiBranch()) {
3427 if (multis.node() == c) {
3428 multis.set_index(i+1);
3429 } else {
3430 multis.push(c, i+1);
3431 }
3432 }
3433 trailing = next;
3434 break;
3435 }
3436 }
3437 if (trailing != nullptr && !seen.test_set(trailing->_idx)) {
3438 break;
3439 }
3440 while (multis.size() > 0) {
3441 c = multis.node();
3442 i = multis.index();
3443 if (i < c->req()) {
3444 break;
3445 }
3446 multis.pop();
3447 }
3448 } while (multis.size() > 0);
3449 } while (!trailing->is_MemBar() || !trailing->as_MemBar()->trailing());
3450
3451 MemBarNode* mb = trailing->as_MemBar();
3452 assert((mb->_kind == TrailingStore && _kind == LeadingStore) ||
3453 (mb->_kind == TrailingLoadStore && _kind == LeadingLoadStore), "bad trailing membar");
3454 assert(mb->_pair_idx == _pair_idx, "bad trailing membar");
3455 return mb;
3456 }
3457
3458 MemBarNode* MemBarNode::leading_membar() const {
3459 ResourceMark rm;
3460 VectorSet seen;
3461 Node_Stack regions(0);
3462 Node* leading = in(0);
3463 while (leading != nullptr && (!leading->is_MemBar() || !leading->as_MemBar()->leading())) {
3464 while (leading == nullptr || leading->is_top() || seen.test_set(leading->_idx)) {
3465 leading = nullptr;
3466 while (regions.size() > 0 && leading == nullptr) {
3467 Node* r = regions.node();
3468 uint i = regions.index();
3469 if (i < r->req()) {
3470 leading = r->in(i);
3471 regions.set_index(i+1);
3472 } else {
3473 regions.pop();
3474 }
3475 }
3476 if (leading == nullptr) {
3477 assert(regions.size() == 0, "all paths should have been tried");
3478 return nullptr;
3479 }
3480 }
3481 if (leading->is_Region()) {
3482 regions.push(leading, 2);
3483 leading = leading->in(1);
3484 } else {
3485 leading = leading->in(0);
3486 }
3487 }
3488 #ifdef ASSERT
3489 Unique_Node_List wq;
3490 wq.push((Node*)this);
3491 uint found = 0;
3492 for (uint i = 0; i < wq.size(); i++) {
3493 Node* n = wq.at(i);
3494 if (n->is_Region()) {
3495 for (uint j = 1; j < n->req(); j++) {
3496 Node* in = n->in(j);
3497 if (in != nullptr && !in->is_top()) {
3498 wq.push(in);
3499 }
3500 }
3501 } else {
3502 if (n->is_MemBar() && n->as_MemBar()->leading()) {
3503 assert(n == leading, "consistency check failed");
3504 found++;
3505 } else {
3506 Node* in = n->in(0);
3507 if (in != nullptr && !in->is_top()) {
3508 wq.push(in);
3509 }
3510 }
3511 }
3512 }
3513 assert(found == 1 || (found == 0 && leading == nullptr), "consistency check failed");
3514 #endif
3515 if (leading == nullptr) {
3516 return nullptr;
3517 }
3518 MemBarNode* mb = leading->as_MemBar();
3519 assert((mb->_kind == LeadingStore && _kind == TrailingStore) ||
3520 (mb->_kind == LeadingLoadStore && _kind == TrailingLoadStore), "bad leading membar");
3521 assert(mb->_pair_idx == _pair_idx, "bad leading membar");
3522 return mb;
3523 }
3524
3525
3526 //===========================InitializeNode====================================
3527 // SUMMARY:
3528 // This node acts as a memory barrier on raw memory, after some raw stores.
3529 // The 'cooked' oop value feeds from the Initialize, not the Allocation.
3530 // The Initialize can 'capture' suitably constrained stores as raw inits.
3531 // It can coalesce related raw stores into larger units (called 'tiles').
3532 // It can avoid zeroing new storage for memory units which have raw inits.
3533 // At macro-expansion, it is marked 'complete', and does not optimize further.
3534 //
3535 // EXAMPLE:
3536 // The object 'new short[2]' occupies 16 bytes in a 32-bit machine.
3537 // ctl = incoming control; mem* = incoming memory
3538 // (Note: A star * on a memory edge denotes I/O and other standard edges.)
3539 // First allocate uninitialized memory and fill in the header:
3540 // alloc = (Allocate ctl mem* 16 #short[].klass ...)
3541 // ctl := alloc.Control; mem* := alloc.Memory*
3542 // rawmem = alloc.Memory; rawoop = alloc.RawAddress
3543 // Then initialize to zero the non-header parts of the raw memory block:
3544 // init = (Initialize alloc.Control alloc.Memory* alloc.RawAddress)
3545 // ctl := init.Control; mem.SLICE(#short[*]) := init.Memory
3546 // After the initialize node executes, the object is ready for service:
3547 // oop := (CheckCastPP init.Control alloc.RawAddress #short[])
3548 // Suppose its body is immediately initialized as {1,2}:
3549 // store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
3550 // store2 = (StoreC init.Control store1 (+ oop 14) 2)
3551 // mem.SLICE(#short[*]) := store2
3552 //
3553 // DETAILS:
3554 // An InitializeNode collects and isolates object initialization after
3555 // an AllocateNode and before the next possible safepoint. As a
3556 // memory barrier (MemBarNode), it keeps critical stores from drifting
3557 // down past any safepoint or any publication of the allocation.
3558 // Before this barrier, a newly-allocated object may have uninitialized bits.
3559 // After this barrier, it may be treated as a real oop, and GC is allowed.
3560 //
3561 // The semantics of the InitializeNode include an implicit zeroing of
3562 // the new object from object header to the end of the object.
3563 // (The object header and end are determined by the AllocateNode.)
3564 //
3565 // Certain stores may be added as direct inputs to the InitializeNode.
3566 // These stores must update raw memory, and they must be to addresses
3567 // derived from the raw address produced by AllocateNode, and with
3568 // a constant offset. They must be ordered by increasing offset.
3569 // The first one is at in(RawStores), the last at in(req()-1).
3570 // Unlike most memory operations, they are not linked in a chain,
3571 // but are displayed in parallel as users of the rawmem output of
3572 // the allocation.
3573 //
3574 // (See comments in InitializeNode::capture_store, which continue
3575 // the example given above.)
3576 //
3577 // When the associated Allocate is macro-expanded, the InitializeNode
3578 // may be rewritten to optimize collected stores. A ClearArrayNode
3579 // may also be created at that point to represent any required zeroing.
3580 // The InitializeNode is then marked 'complete', prohibiting further
3581 // capturing of nearby memory operations.
3582 //
3583 // During macro-expansion, all captured initializations which store
3584 // constant values of 32 bits or smaller are coalesced (if advantageous)
3585 // into larger 'tiles' 32 or 64 bits. This allows an object to be
3586 // initialized in fewer memory operations. Memory words which are
3587 // covered by neither tiles nor non-constant stores are pre-zeroed
3588 // by explicit stores of zero. (The code shape happens to do all
3589 // zeroing first, then all other stores, with both sequences occurring
3590 // in order of ascending offsets.)
3591 //
3592 // Alternatively, code may be inserted between an AllocateNode and its
3593 // InitializeNode, to perform arbitrary initialization of the new object.
3594 // E.g., the object copying intrinsics insert complex data transfers here.
3595 // The initialization must then be marked as 'complete' disable the
3596 // built-in zeroing semantics and the collection of initializing stores.
3597 //
3598 // While an InitializeNode is incomplete, reads from the memory state
3599 // produced by it are optimizable if they match the control edge and
3600 // new oop address associated with the allocation/initialization.
3601 // They return a stored value (if the offset matches) or else zero.
3602 // A write to the memory state, if it matches control and address,
3603 // and if it is to a constant offset, may be 'captured' by the
3604 // InitializeNode. It is cloned as a raw memory operation and rewired
3605 // inside the initialization, to the raw oop produced by the allocation.
3606 // Operations on addresses which are provably distinct (e.g., to
3607 // other AllocateNodes) are allowed to bypass the initialization.
3608 //
3609 // The effect of all this is to consolidate object initialization
3610 // (both arrays and non-arrays, both piecewise and bulk) into a
3611 // single location, where it can be optimized as a unit.
3612 //
3613 // Only stores with an offset less than TrackedInitializationLimit words
3614 // will be considered for capture by an InitializeNode. This puts a
3615 // reasonable limit on the complexity of optimized initializations.
3616
3617 //---------------------------InitializeNode------------------------------------
3618 InitializeNode::InitializeNode(Compile* C, int adr_type, Node* rawoop)
3619 : MemBarNode(C, adr_type, rawoop),
3620 _is_complete(Incomplete), _does_not_escape(false)
3621 {
3622 init_class_id(Class_Initialize);
3623
3624 assert(adr_type == Compile::AliasIdxRaw, "only valid atp");
3625 assert(in(RawAddress) == rawoop, "proper init");
3626 // Note: allocation() can be null, for secondary initialization barriers
3627 }
3628
3629 // Since this node is not matched, it will be processed by the
3630 // register allocator. Declare that there are no constraints
3631 // on the allocation of the RawAddress edge.
3632 const RegMask &InitializeNode::in_RegMask(uint idx) const {
3633 // This edge should be set to top, by the set_complete. But be conservative.
3634 if (idx == InitializeNode::RawAddress)
3635 return *(Compile::current()->matcher()->idealreg2spillmask[in(idx)->ideal_reg()]);
3636 return RegMask::Empty;
3637 }
3638
3639 Node* InitializeNode::memory(uint alias_idx) {
3640 Node* mem = in(Memory);
3641 if (mem->is_MergeMem()) {
3642 return mem->as_MergeMem()->memory_at(alias_idx);
3643 } else {
3644 // incoming raw memory is not split
3645 return mem;
3646 }
3647 }
3648
3649 bool InitializeNode::is_non_zero() {
3650 if (is_complete()) return false;
3651 remove_extra_zeroes();
3652 return (req() > RawStores);
3653 }
3654
3655 void InitializeNode::set_complete(PhaseGVN* phase) {
3656 assert(!is_complete(), "caller responsibility");
3657 _is_complete = Complete;
3658
3659 // After this node is complete, it contains a bunch of
3660 // raw-memory initializations. There is no need for
3661 // it to have anything to do with non-raw memory effects.
3662 // Therefore, tell all non-raw users to re-optimize themselves,
3663 // after skipping the memory effects of this initialization.
3664 PhaseIterGVN* igvn = phase->is_IterGVN();
3665 if (igvn) igvn->add_users_to_worklist(this);
3666 }
3667
3668 // convenience function
3669 // return false if the init contains any stores already
3670 bool AllocateNode::maybe_set_complete(PhaseGVN* phase) {
3671 InitializeNode* init = initialization();
3672 if (init == nullptr || init->is_complete()) return false;
3673 init->remove_extra_zeroes();
3674 // for now, if this allocation has already collected any inits, bail:
3675 if (init->is_non_zero()) return false;
3676 init->set_complete(phase);
3677 return true;
3678 }
3679
3680 void InitializeNode::remove_extra_zeroes() {
3681 if (req() == RawStores) return;
3682 Node* zmem = zero_memory();
3683 uint fill = RawStores;
3684 for (uint i = fill; i < req(); i++) {
3685 Node* n = in(i);
3686 if (n->is_top() || n == zmem) continue; // skip
3687 if (fill < i) set_req(fill, n); // compact
3688 ++fill;
3689 }
3690 // delete any empty spaces created:
3691 while (fill < req()) {
3692 del_req(fill);
3693 }
3694 }
3695
3696 // Helper for remembering which stores go with which offsets.
3697 intptr_t InitializeNode::get_store_offset(Node* st, PhaseValues* phase) {
3698 if (!st->is_Store()) return -1; // can happen to dead code via subsume_node
3699 intptr_t offset = -1;
3700 Node* base = AddPNode::Ideal_base_and_offset(st->in(MemNode::Address),
3701 phase, offset);
3702 if (base == nullptr) return -1; // something is dead,
3703 if (offset < 0) return -1; // dead, dead
3704 return offset;
3705 }
3706
3707 // Helper for proving that an initialization expression is
3708 // "simple enough" to be folded into an object initialization.
3709 // Attempts to prove that a store's initial value 'n' can be captured
3710 // within the initialization without creating a vicious cycle, such as:
3711 // { Foo p = new Foo(); p.next = p; }
3712 // True for constants and parameters and small combinations thereof.
3713 bool InitializeNode::detect_init_independence(Node* value, PhaseGVN* phase) {
3714 ResourceMark rm;
3715 Unique_Node_List worklist;
3716 worklist.push(value);
3717
3718 uint complexity_limit = 20;
3719 for (uint j = 0; j < worklist.size(); j++) {
3720 if (j >= complexity_limit) {
3721 return false; // Bail out if processed too many nodes
3722 }
3723
3724 Node* n = worklist.at(j);
3725 if (n == nullptr) continue; // (can this really happen?)
3726 if (n->is_Proj()) n = n->in(0);
3727 if (n == this) return false; // found a cycle
3728 if (n->is_Con()) continue;
3729 if (n->is_Start()) continue; // params, etc., are OK
3730 if (n->is_Root()) continue; // even better
3731
3732 // There cannot be any dependency if 'n' is a CFG node that dominates the current allocation
3733 if (n->is_CFG() && phase->is_dominator(n, allocation())) {
3734 continue;
3735 }
3736
3737 Node* ctl = n->in(0);
3738 if (ctl != nullptr && !ctl->is_top()) {
3739 if (ctl->is_Proj()) ctl = ctl->in(0);
3740 if (ctl == this) return false;
3741
3742 // If we already know that the enclosing memory op is pinned right after
3743 // the init, then any control flow that the store has picked up
3744 // must have preceded the init, or else be equal to the init.
3745 // Even after loop optimizations (which might change control edges)
3746 // a store is never pinned *before* the availability of its inputs.
3747 if (!MemNode::all_controls_dominate(n, this))
3748 return false; // failed to prove a good control
3749 }
3750
3751 // Check data edges for possible dependencies on 'this'.
3752 for (uint i = 1; i < n->req(); i++) {
3753 Node* m = n->in(i);
3754 if (m == nullptr || m == n || m->is_top()) continue;
3755
3756 // Only process data inputs once
3757 worklist.push(m);
3758 }
3759 }
3760
3761 return true;
3762 }
3763
3764 // Here are all the checks a Store must pass before it can be moved into
3765 // an initialization. Returns zero if a check fails.
3766 // On success, returns the (constant) offset to which the store applies,
3767 // within the initialized memory.
3768 intptr_t InitializeNode::can_capture_store(StoreNode* st, PhaseGVN* phase, bool can_reshape) {
3769 const int FAIL = 0;
3770 if (st->req() != MemNode::ValueIn + 1)
3771 return FAIL; // an inscrutable StoreNode (card mark?)
3772 Node* ctl = st->in(MemNode::Control);
3773 if (!(ctl != nullptr && ctl->is_Proj() && ctl->in(0) == this))
3774 return FAIL; // must be unconditional after the initialization
3775 Node* mem = st->in(MemNode::Memory);
3776 if (!(mem->is_Proj() && mem->in(0) == this))
3777 return FAIL; // must not be preceded by other stores
3778 Node* adr = st->in(MemNode::Address);
3779 intptr_t offset;
3780 AllocateNode* alloc = AllocateNode::Ideal_allocation(adr, phase, offset);
3781 if (alloc == nullptr)
3782 return FAIL; // inscrutable address
3783 if (alloc != allocation())
3784 return FAIL; // wrong allocation! (store needs to float up)
3785 int size_in_bytes = st->memory_size();
3786 if ((size_in_bytes != 0) && (offset % size_in_bytes) != 0) {
3787 return FAIL; // mismatched access
3788 }
3789 Node* val = st->in(MemNode::ValueIn);
3790
3791 if (!detect_init_independence(val, phase))
3792 return FAIL; // stored value must be 'simple enough'
3793
3794 // The Store can be captured only if nothing after the allocation
3795 // and before the Store is using the memory location that the store
3796 // overwrites.
3797 bool failed = false;
3798 // If is_complete_with_arraycopy() is true the shape of the graph is
3799 // well defined and is safe so no need for extra checks.
3800 if (!is_complete_with_arraycopy()) {
3801 // We are going to look at each use of the memory state following
3802 // the allocation to make sure nothing reads the memory that the
3803 // Store writes.
3804 const TypePtr* t_adr = phase->type(adr)->isa_ptr();
3805 int alias_idx = phase->C->get_alias_index(t_adr);
3806 ResourceMark rm;
3807 Unique_Node_List mems;
3808 mems.push(mem);
3809 Node* unique_merge = nullptr;
3810 for (uint next = 0; next < mems.size(); ++next) {
3811 Node *m = mems.at(next);
3812 for (DUIterator_Fast jmax, j = m->fast_outs(jmax); j < jmax; j++) {
3813 Node *n = m->fast_out(j);
3814 if (n->outcnt() == 0) {
3815 continue;
3816 }
3817 if (n == st) {
3818 continue;
3819 } else if (n->in(0) != nullptr && n->in(0) != ctl) {
3820 // If the control of this use is different from the control
3821 // of the Store which is right after the InitializeNode then
3822 // this node cannot be between the InitializeNode and the
3823 // Store.
3824 continue;
3825 } else if (n->is_MergeMem()) {
3826 if (n->as_MergeMem()->memory_at(alias_idx) == m) {
3827 // We can hit a MergeMemNode (that will likely go away
3828 // later) that is a direct use of the memory state
3829 // following the InitializeNode on the same slice as the
3830 // store node that we'd like to capture. We need to check
3831 // the uses of the MergeMemNode.
3832 mems.push(n);
3833 }
3834 } else if (n->is_Mem()) {
3835 Node* other_adr = n->in(MemNode::Address);
3836 if (other_adr == adr) {
3837 failed = true;
3838 break;
3839 } else {
3840 const TypePtr* other_t_adr = phase->type(other_adr)->isa_ptr();
3841 if (other_t_adr != nullptr) {
3842 int other_alias_idx = phase->C->get_alias_index(other_t_adr);
3843 if (other_alias_idx == alias_idx) {
3844 // A load from the same memory slice as the store right
3845 // after the InitializeNode. We check the control of the
3846 // object/array that is loaded from. If it's the same as
3847 // the store control then we cannot capture the store.
3848 assert(!n->is_Store(), "2 stores to same slice on same control?");
3849 Node* base = other_adr;
3850 assert(base->is_AddP(), "should be addp but is %s", base->Name());
3851 base = base->in(AddPNode::Base);
3852 if (base != nullptr) {
3853 base = base->uncast();
3854 if (base->is_Proj() && base->in(0) == alloc) {
3855 failed = true;
3856 break;
3857 }
3858 }
3859 }
3860 }
3861 }
3862 } else {
3863 failed = true;
3864 break;
3865 }
3866 }
3867 }
3868 }
3869 if (failed) {
3870 if (!can_reshape) {
3871 // We decided we couldn't capture the store during parsing. We
3872 // should try again during the next IGVN once the graph is
3873 // cleaner.
3874 phase->C->record_for_igvn(st);
3875 }
3876 return FAIL;
3877 }
3878
3879 return offset; // success
3880 }
3881
3882 // Find the captured store in(i) which corresponds to the range
3883 // [start..start+size) in the initialized object.
3884 // If there is one, return its index i. If there isn't, return the
3885 // negative of the index where it should be inserted.
3886 // Return 0 if the queried range overlaps an initialization boundary
3887 // or if dead code is encountered.
3888 // If size_in_bytes is zero, do not bother with overlap checks.
3889 int InitializeNode::captured_store_insertion_point(intptr_t start,
3890 int size_in_bytes,
3891 PhaseValues* phase) {
3892 const int FAIL = 0, MAX_STORE = MAX2(BytesPerLong, (int)MaxVectorSize);
3893
3894 if (is_complete())
3895 return FAIL; // arraycopy got here first; punt
3896
3897 assert(allocation() != nullptr, "must be present");
3898
3899 // no negatives, no header fields:
3900 if (start < (intptr_t) allocation()->minimum_header_size()) return FAIL;
3901
3902 // after a certain size, we bail out on tracking all the stores:
3903 intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
3904 if (start >= ti_limit) return FAIL;
3905
3906 for (uint i = InitializeNode::RawStores, limit = req(); ; ) {
3907 if (i >= limit) return -(int)i; // not found; here is where to put it
3908
3909 Node* st = in(i);
3910 intptr_t st_off = get_store_offset(st, phase);
3911 if (st_off < 0) {
3912 if (st != zero_memory()) {
3913 return FAIL; // bail out if there is dead garbage
3914 }
3915 } else if (st_off > start) {
3916 // ...we are done, since stores are ordered
3917 if (st_off < start + size_in_bytes) {
3918 return FAIL; // the next store overlaps
3919 }
3920 return -(int)i; // not found; here is where to put it
3921 } else if (st_off < start) {
3922 assert(st->as_Store()->memory_size() <= MAX_STORE, "");
3923 if (size_in_bytes != 0 &&
3924 start < st_off + MAX_STORE &&
3925 start < st_off + st->as_Store()->memory_size()) {
3926 return FAIL; // the previous store overlaps
3927 }
3928 } else {
3929 if (size_in_bytes != 0 &&
3930 st->as_Store()->memory_size() != size_in_bytes) {
3931 return FAIL; // mismatched store size
3932 }
3933 return i;
3934 }
3935
3936 ++i;
3937 }
3938 }
3939
3940 // Look for a captured store which initializes at the offset 'start'
3941 // with the given size. If there is no such store, and no other
3942 // initialization interferes, then return zero_memory (the memory
3943 // projection of the AllocateNode).
3944 Node* InitializeNode::find_captured_store(intptr_t start, int size_in_bytes,
3945 PhaseValues* phase) {
3946 assert(stores_are_sane(phase), "");
3947 int i = captured_store_insertion_point(start, size_in_bytes, phase);
3948 if (i == 0) {
3949 return nullptr; // something is dead
3950 } else if (i < 0) {
3951 return zero_memory(); // just primordial zero bits here
3952 } else {
3953 Node* st = in(i); // here is the store at this position
3954 assert(get_store_offset(st->as_Store(), phase) == start, "sanity");
3955 return st;
3956 }
3957 }
3958
3959 // Create, as a raw pointer, an address within my new object at 'offset'.
3960 Node* InitializeNode::make_raw_address(intptr_t offset,
3961 PhaseGVN* phase) {
3962 Node* addr = in(RawAddress);
3963 if (offset != 0) {
3964 Compile* C = phase->C;
3965 addr = phase->transform( new AddPNode(C->top(), addr,
3966 phase->MakeConX(offset)) );
3967 }
3968 return addr;
3969 }
3970
3971 // Clone the given store, converting it into a raw store
3972 // initializing a field or element of my new object.
3973 // Caller is responsible for retiring the original store,
3974 // with subsume_node or the like.
3975 //
3976 // From the example above InitializeNode::InitializeNode,
3977 // here are the old stores to be captured:
3978 // store1 = (StoreC init.Control init.Memory (+ oop 12) 1)
3979 // store2 = (StoreC init.Control store1 (+ oop 14) 2)
3980 //
3981 // Here is the changed code; note the extra edges on init:
3982 // alloc = (Allocate ...)
3983 // rawoop = alloc.RawAddress
3984 // rawstore1 = (StoreC alloc.Control alloc.Memory (+ rawoop 12) 1)
3985 // rawstore2 = (StoreC alloc.Control alloc.Memory (+ rawoop 14) 2)
3986 // init = (Initialize alloc.Control alloc.Memory rawoop
3987 // rawstore1 rawstore2)
3988 //
3989 Node* InitializeNode::capture_store(StoreNode* st, intptr_t start,
3990 PhaseGVN* phase, bool can_reshape) {
3991 assert(stores_are_sane(phase), "");
3992
3993 if (start < 0) return nullptr;
3994 assert(can_capture_store(st, phase, can_reshape) == start, "sanity");
3995
3996 Compile* C = phase->C;
3997 int size_in_bytes = st->memory_size();
3998 int i = captured_store_insertion_point(start, size_in_bytes, phase);
3999 if (i == 0) return nullptr; // bail out
4000 Node* prev_mem = nullptr; // raw memory for the captured store
4001 if (i > 0) {
4002 prev_mem = in(i); // there is a pre-existing store under this one
4003 set_req(i, C->top()); // temporarily disconnect it
4004 // See StoreNode::Ideal 'st->outcnt() == 1' for the reason to disconnect.
4005 } else {
4006 i = -i; // no pre-existing store
4007 prev_mem = zero_memory(); // a slice of the newly allocated object
4008 if (i > InitializeNode::RawStores && in(i-1) == prev_mem)
4009 set_req(--i, C->top()); // reuse this edge; it has been folded away
4010 else
4011 ins_req(i, C->top()); // build a new edge
4012 }
4013 Node* new_st = st->clone();
4014 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
4015 new_st->set_req(MemNode::Control, in(Control));
4016 new_st->set_req(MemNode::Memory, prev_mem);
4017 new_st->set_req(MemNode::Address, make_raw_address(start, phase));
4018 bs->eliminate_gc_barrier_data(new_st);
4019 new_st = phase->transform(new_st);
4020
4021 // At this point, new_st might have swallowed a pre-existing store
4022 // at the same offset, or perhaps new_st might have disappeared,
4023 // if it redundantly stored the same value (or zero to fresh memory).
4024
4025 // In any case, wire it in:
4026 PhaseIterGVN* igvn = phase->is_IterGVN();
4027 if (igvn) {
4028 igvn->rehash_node_delayed(this);
4029 }
4030 set_req(i, new_st);
4031
4032 // The caller may now kill the old guy.
4033 DEBUG_ONLY(Node* check_st = find_captured_store(start, size_in_bytes, phase));
4034 assert(check_st == new_st || check_st == nullptr, "must be findable");
4035 assert(!is_complete(), "");
4036 return new_st;
4037 }
4038
4039 static bool store_constant(jlong* tiles, int num_tiles,
4040 intptr_t st_off, int st_size,
4041 jlong con) {
4042 if ((st_off & (st_size-1)) != 0)
4043 return false; // strange store offset (assume size==2**N)
4044 address addr = (address)tiles + st_off;
4045 assert(st_off >= 0 && addr+st_size <= (address)&tiles[num_tiles], "oob");
4046 switch (st_size) {
4047 case sizeof(jbyte): *(jbyte*) addr = (jbyte) con; break;
4048 case sizeof(jchar): *(jchar*) addr = (jchar) con; break;
4049 case sizeof(jint): *(jint*) addr = (jint) con; break;
4050 case sizeof(jlong): *(jlong*) addr = (jlong) con; break;
4051 default: return false; // strange store size (detect size!=2**N here)
4052 }
4053 return true; // return success to caller
4054 }
4055
4056 // Coalesce subword constants into int constants and possibly
4057 // into long constants. The goal, if the CPU permits,
4058 // is to initialize the object with a small number of 64-bit tiles.
4059 // Also, convert floating-point constants to bit patterns.
4060 // Non-constants are not relevant to this pass.
4061 //
4062 // In terms of the running example on InitializeNode::InitializeNode
4063 // and InitializeNode::capture_store, here is the transformation
4064 // of rawstore1 and rawstore2 into rawstore12:
4065 // alloc = (Allocate ...)
4066 // rawoop = alloc.RawAddress
4067 // tile12 = 0x00010002
4068 // rawstore12 = (StoreI alloc.Control alloc.Memory (+ rawoop 12) tile12)
4069 // init = (Initialize alloc.Control alloc.Memory rawoop rawstore12)
4070 //
4071 void
4072 InitializeNode::coalesce_subword_stores(intptr_t header_size,
4073 Node* size_in_bytes,
4074 PhaseGVN* phase) {
4075 Compile* C = phase->C;
4076
4077 assert(stores_are_sane(phase), "");
4078 // Note: After this pass, they are not completely sane,
4079 // since there may be some overlaps.
4080
4081 int old_subword = 0, old_long = 0, new_int = 0, new_long = 0;
4082
4083 intptr_t ti_limit = (TrackedInitializationLimit * HeapWordSize);
4084 intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, ti_limit);
4085 size_limit = MIN2(size_limit, ti_limit);
4086 size_limit = align_up(size_limit, BytesPerLong);
4087 int num_tiles = size_limit / BytesPerLong;
4088
4089 // allocate space for the tile map:
4090 const int small_len = DEBUG_ONLY(true ? 3 :) 30; // keep stack frames small
4091 jlong tiles_buf[small_len];
4092 Node* nodes_buf[small_len];
4093 jlong inits_buf[small_len];
4094 jlong* tiles = ((num_tiles <= small_len) ? &tiles_buf[0]
4095 : NEW_RESOURCE_ARRAY(jlong, num_tiles));
4096 Node** nodes = ((num_tiles <= small_len) ? &nodes_buf[0]
4097 : NEW_RESOURCE_ARRAY(Node*, num_tiles));
4098 jlong* inits = ((num_tiles <= small_len) ? &inits_buf[0]
4099 : NEW_RESOURCE_ARRAY(jlong, num_tiles));
4100 // tiles: exact bitwise model of all primitive constants
4101 // nodes: last constant-storing node subsumed into the tiles model
4102 // inits: which bytes (in each tile) are touched by any initializations
4103
4104 //// Pass A: Fill in the tile model with any relevant stores.
4105
4106 Copy::zero_to_bytes(tiles, sizeof(tiles[0]) * num_tiles);
4107 Copy::zero_to_bytes(nodes, sizeof(nodes[0]) * num_tiles);
4108 Copy::zero_to_bytes(inits, sizeof(inits[0]) * num_tiles);
4109 Node* zmem = zero_memory(); // initially zero memory state
4110 for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
4111 Node* st = in(i);
4112 intptr_t st_off = get_store_offset(st, phase);
4113
4114 // Figure out the store's offset and constant value:
4115 if (st_off < header_size) continue; //skip (ignore header)
4116 if (st->in(MemNode::Memory) != zmem) continue; //skip (odd store chain)
4117 int st_size = st->as_Store()->memory_size();
4118 if (st_off + st_size > size_limit) break;
4119
4120 // Record which bytes are touched, whether by constant or not.
4121 if (!store_constant(inits, num_tiles, st_off, st_size, (jlong) -1))
4122 continue; // skip (strange store size)
4123
4124 const Type* val = phase->type(st->in(MemNode::ValueIn));
4125 if (!val->singleton()) continue; //skip (non-con store)
4126 BasicType type = val->basic_type();
4127
4128 jlong con = 0;
4129 switch (type) {
4130 case T_INT: con = val->is_int()->get_con(); break;
4131 case T_LONG: con = val->is_long()->get_con(); break;
4132 case T_FLOAT: con = jint_cast(val->getf()); break;
4133 case T_DOUBLE: con = jlong_cast(val->getd()); break;
4134 default: continue; //skip (odd store type)
4135 }
4136
4137 if (type == T_LONG && Matcher::isSimpleConstant64(con) &&
4138 st->Opcode() == Op_StoreL) {
4139 continue; // This StoreL is already optimal.
4140 }
4141
4142 // Store down the constant.
4143 store_constant(tiles, num_tiles, st_off, st_size, con);
4144
4145 intptr_t j = st_off >> LogBytesPerLong;
4146
4147 if (type == T_INT && st_size == BytesPerInt
4148 && (st_off & BytesPerInt) == BytesPerInt) {
4149 jlong lcon = tiles[j];
4150 if (!Matcher::isSimpleConstant64(lcon) &&
4151 st->Opcode() == Op_StoreI) {
4152 // This StoreI is already optimal by itself.
4153 jint* intcon = (jint*) &tiles[j];
4154 intcon[1] = 0; // undo the store_constant()
4155
4156 // If the previous store is also optimal by itself, back up and
4157 // undo the action of the previous loop iteration... if we can.
4158 // But if we can't, just let the previous half take care of itself.
4159 st = nodes[j];
4160 st_off -= BytesPerInt;
4161 con = intcon[0];
4162 if (con != 0 && st != nullptr && st->Opcode() == Op_StoreI) {
4163 assert(st_off >= header_size, "still ignoring header");
4164 assert(get_store_offset(st, phase) == st_off, "must be");
4165 assert(in(i-1) == zmem, "must be");
4166 DEBUG_ONLY(const Type* tcon = phase->type(st->in(MemNode::ValueIn)));
4167 assert(con == tcon->is_int()->get_con(), "must be");
4168 // Undo the effects of the previous loop trip, which swallowed st:
4169 intcon[0] = 0; // undo store_constant()
4170 set_req(i-1, st); // undo set_req(i, zmem)
4171 nodes[j] = nullptr; // undo nodes[j] = st
4172 --old_subword; // undo ++old_subword
4173 }
4174 continue; // This StoreI is already optimal.
4175 }
4176 }
4177
4178 // This store is not needed.
4179 set_req(i, zmem);
4180 nodes[j] = st; // record for the moment
4181 if (st_size < BytesPerLong) // something has changed
4182 ++old_subword; // includes int/float, but who's counting...
4183 else ++old_long;
4184 }
4185
4186 if ((old_subword + old_long) == 0)
4187 return; // nothing more to do
4188
4189 //// Pass B: Convert any non-zero tiles into optimal constant stores.
4190 // Be sure to insert them before overlapping non-constant stores.
4191 // (E.g., byte[] x = { 1,2,y,4 } => x[int 0] = 0x01020004, x[2]=y.)
4192 for (int j = 0; j < num_tiles; j++) {
4193 jlong con = tiles[j];
4194 jlong init = inits[j];
4195 if (con == 0) continue;
4196 jint con0, con1; // split the constant, address-wise
4197 jint init0, init1; // split the init map, address-wise
4198 { union { jlong con; jint intcon[2]; } u;
4199 u.con = con;
4200 con0 = u.intcon[0];
4201 con1 = u.intcon[1];
4202 u.con = init;
4203 init0 = u.intcon[0];
4204 init1 = u.intcon[1];
4205 }
4206
4207 Node* old = nodes[j];
4208 assert(old != nullptr, "need the prior store");
4209 intptr_t offset = (j * BytesPerLong);
4210
4211 bool split = !Matcher::isSimpleConstant64(con);
4212
4213 if (offset < header_size) {
4214 assert(offset + BytesPerInt >= header_size, "second int counts");
4215 assert(*(jint*)&tiles[j] == 0, "junk in header");
4216 split = true; // only the second word counts
4217 // Example: int a[] = { 42 ... }
4218 } else if (con0 == 0 && init0 == -1) {
4219 split = true; // first word is covered by full inits
4220 // Example: int a[] = { ... foo(), 42 ... }
4221 } else if (con1 == 0 && init1 == -1) {
4222 split = true; // second word is covered by full inits
4223 // Example: int a[] = { ... 42, foo() ... }
4224 }
4225
4226 // Here's a case where init0 is neither 0 nor -1:
4227 // byte a[] = { ... 0,0,foo(),0, 0,0,0,42 ... }
4228 // Assuming big-endian memory, init0, init1 are 0x0000FF00, 0x000000FF.
4229 // In this case the tile is not split; it is (jlong)42.
4230 // The big tile is stored down, and then the foo() value is inserted.
4231 // (If there were foo(),foo() instead of foo(),0, init0 would be -1.)
4232
4233 Node* ctl = old->in(MemNode::Control);
4234 Node* adr = make_raw_address(offset, phase);
4235 const TypePtr* atp = TypeRawPtr::BOTTOM;
4236
4237 // One or two coalesced stores to plop down.
4238 Node* st[2];
4239 intptr_t off[2];
4240 int nst = 0;
4241 if (!split) {
4242 ++new_long;
4243 off[nst] = offset;
4244 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp,
4245 phase->longcon(con), T_LONG, MemNode::unordered);
4246 } else {
4247 // Omit either if it is a zero.
4248 if (con0 != 0) {
4249 ++new_int;
4250 off[nst] = offset;
4251 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp,
4252 phase->intcon(con0), T_INT, MemNode::unordered);
4253 }
4254 if (con1 != 0) {
4255 ++new_int;
4256 offset += BytesPerInt;
4257 adr = make_raw_address(offset, phase);
4258 off[nst] = offset;
4259 st[nst++] = StoreNode::make(*phase, ctl, zmem, adr, atp,
4260 phase->intcon(con1), T_INT, MemNode::unordered);
4261 }
4262 }
4263
4264 // Insert second store first, then the first before the second.
4265 // Insert each one just before any overlapping non-constant stores.
4266 while (nst > 0) {
4267 Node* st1 = st[--nst];
4268 C->copy_node_notes_to(st1, old);
4269 st1 = phase->transform(st1);
4270 offset = off[nst];
4271 assert(offset >= header_size, "do not smash header");
4272 int ins_idx = captured_store_insertion_point(offset, /*size:*/0, phase);
4273 guarantee(ins_idx != 0, "must re-insert constant store");
4274 if (ins_idx < 0) ins_idx = -ins_idx; // never overlap
4275 if (ins_idx > InitializeNode::RawStores && in(ins_idx-1) == zmem)
4276 set_req(--ins_idx, st1);
4277 else
4278 ins_req(ins_idx, st1);
4279 }
4280 }
4281
4282 if (PrintCompilation && WizardMode)
4283 tty->print_cr("Changed %d/%d subword/long constants into %d/%d int/long",
4284 old_subword, old_long, new_int, new_long);
4285 if (C->log() != nullptr)
4286 C->log()->elem("comment that='%d/%d subword/long to %d/%d int/long'",
4287 old_subword, old_long, new_int, new_long);
4288
4289 // Clean up any remaining occurrences of zmem:
4290 remove_extra_zeroes();
4291 }
4292
4293 // Explore forward from in(start) to find the first fully initialized
4294 // word, and return its offset. Skip groups of subword stores which
4295 // together initialize full words. If in(start) is itself part of a
4296 // fully initialized word, return the offset of in(start). If there
4297 // are no following full-word stores, or if something is fishy, return
4298 // a negative value.
4299 intptr_t InitializeNode::find_next_fullword_store(uint start, PhaseGVN* phase) {
4300 int int_map = 0;
4301 intptr_t int_map_off = 0;
4302 const int FULL_MAP = right_n_bits(BytesPerInt); // the int_map we hope for
4303
4304 for (uint i = start, limit = req(); i < limit; i++) {
4305 Node* st = in(i);
4306
4307 intptr_t st_off = get_store_offset(st, phase);
4308 if (st_off < 0) break; // return conservative answer
4309
4310 int st_size = st->as_Store()->memory_size();
4311 if (st_size >= BytesPerInt && (st_off % BytesPerInt) == 0) {
4312 return st_off; // we found a complete word init
4313 }
4314
4315 // update the map:
4316
4317 intptr_t this_int_off = align_down(st_off, BytesPerInt);
4318 if (this_int_off != int_map_off) {
4319 // reset the map:
4320 int_map = 0;
4321 int_map_off = this_int_off;
4322 }
4323
4324 int subword_off = st_off - this_int_off;
4325 int_map |= right_n_bits(st_size) << subword_off;
4326 if ((int_map & FULL_MAP) == FULL_MAP) {
4327 return this_int_off; // we found a complete word init
4328 }
4329
4330 // Did this store hit or cross the word boundary?
4331 intptr_t next_int_off = align_down(st_off + st_size, BytesPerInt);
4332 if (next_int_off == this_int_off + BytesPerInt) {
4333 // We passed the current int, without fully initializing it.
4334 int_map_off = next_int_off;
4335 int_map >>= BytesPerInt;
4336 } else if (next_int_off > this_int_off + BytesPerInt) {
4337 // We passed the current and next int.
4338 return this_int_off + BytesPerInt;
4339 }
4340 }
4341
4342 return -1;
4343 }
4344
4345
4346 // Called when the associated AllocateNode is expanded into CFG.
4347 // At this point, we may perform additional optimizations.
4348 // Linearize the stores by ascending offset, to make memory
4349 // activity as coherent as possible.
4350 Node* InitializeNode::complete_stores(Node* rawctl, Node* rawmem, Node* rawptr,
4351 intptr_t header_size,
4352 Node* size_in_bytes,
4353 PhaseIterGVN* phase) {
4354 assert(!is_complete(), "not already complete");
4355 assert(stores_are_sane(phase), "");
4356 assert(allocation() != nullptr, "must be present");
4357
4358 remove_extra_zeroes();
4359
4360 if (ReduceFieldZeroing || ReduceBulkZeroing)
4361 // reduce instruction count for common initialization patterns
4362 coalesce_subword_stores(header_size, size_in_bytes, phase);
4363
4364 Node* zmem = zero_memory(); // initially zero memory state
4365 Node* inits = zmem; // accumulating a linearized chain of inits
4366 #ifdef ASSERT
4367 intptr_t first_offset = allocation()->minimum_header_size();
4368 intptr_t last_init_off = first_offset; // previous init offset
4369 intptr_t last_init_end = first_offset; // previous init offset+size
4370 intptr_t last_tile_end = first_offset; // previous tile offset+size
4371 #endif
4372 intptr_t zeroes_done = header_size;
4373
4374 bool do_zeroing = true; // we might give up if inits are very sparse
4375 int big_init_gaps = 0; // how many large gaps have we seen?
4376
4377 if (UseTLAB && ZeroTLAB) do_zeroing = false;
4378 if (!ReduceFieldZeroing && !ReduceBulkZeroing) do_zeroing = false;
4379
4380 for (uint i = InitializeNode::RawStores, limit = req(); i < limit; i++) {
4381 Node* st = in(i);
4382 intptr_t st_off = get_store_offset(st, phase);
4383 if (st_off < 0)
4384 break; // unknown junk in the inits
4385 if (st->in(MemNode::Memory) != zmem)
4386 break; // complicated store chains somehow in list
4387
4388 int st_size = st->as_Store()->memory_size();
4389 intptr_t next_init_off = st_off + st_size;
4390
4391 if (do_zeroing && zeroes_done < next_init_off) {
4392 // See if this store needs a zero before it or under it.
4393 intptr_t zeroes_needed = st_off;
4394
4395 if (st_size < BytesPerInt) {
4396 // Look for subword stores which only partially initialize words.
4397 // If we find some, we must lay down some word-level zeroes first,
4398 // underneath the subword stores.
4399 //
4400 // Examples:
4401 // byte[] a = { p,q,r,s } => a[0]=p,a[1]=q,a[2]=r,a[3]=s
4402 // byte[] a = { x,y,0,0 } => a[0..3] = 0, a[0]=x,a[1]=y
4403 // byte[] a = { 0,0,z,0 } => a[0..3] = 0, a[2]=z
4404 //
4405 // Note: coalesce_subword_stores may have already done this,
4406 // if it was prompted by constant non-zero subword initializers.
4407 // But this case can still arise with non-constant stores.
4408
4409 intptr_t next_full_store = find_next_fullword_store(i, phase);
4410
4411 // In the examples above:
4412 // in(i) p q r s x y z
4413 // st_off 12 13 14 15 12 13 14
4414 // st_size 1 1 1 1 1 1 1
4415 // next_full_s. 12 16 16 16 16 16 16
4416 // z's_done 12 16 16 16 12 16 12
4417 // z's_needed 12 16 16 16 16 16 16
4418 // zsize 0 0 0 0 4 0 4
4419 if (next_full_store < 0) {
4420 // Conservative tack: Zero to end of current word.
4421 zeroes_needed = align_up(zeroes_needed, BytesPerInt);
4422 } else {
4423 // Zero to beginning of next fully initialized word.
4424 // Or, don't zero at all, if we are already in that word.
4425 assert(next_full_store >= zeroes_needed, "must go forward");
4426 assert((next_full_store & (BytesPerInt-1)) == 0, "even boundary");
4427 zeroes_needed = next_full_store;
4428 }
4429 }
4430
4431 if (zeroes_needed > zeroes_done) {
4432 intptr_t zsize = zeroes_needed - zeroes_done;
4433 // Do some incremental zeroing on rawmem, in parallel with inits.
4434 zeroes_done = align_down(zeroes_done, BytesPerInt);
4435 rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
4436 zeroes_done, zeroes_needed,
4437 phase);
4438 zeroes_done = zeroes_needed;
4439 if (zsize > InitArrayShortSize && ++big_init_gaps > 2)
4440 do_zeroing = false; // leave the hole, next time
4441 }
4442 }
4443
4444 // Collect the store and move on:
4445 phase->replace_input_of(st, MemNode::Memory, inits);
4446 inits = st; // put it on the linearized chain
4447 set_req(i, zmem); // unhook from previous position
4448
4449 if (zeroes_done == st_off)
4450 zeroes_done = next_init_off;
4451
4452 assert(!do_zeroing || zeroes_done >= next_init_off, "don't miss any");
4453
4454 #ifdef ASSERT
4455 // Various order invariants. Weaker than stores_are_sane because
4456 // a large constant tile can be filled in by smaller non-constant stores.
4457 assert(st_off >= last_init_off, "inits do not reverse");
4458 last_init_off = st_off;
4459 const Type* val = nullptr;
4460 if (st_size >= BytesPerInt &&
4461 (val = phase->type(st->in(MemNode::ValueIn)))->singleton() &&
4462 (int)val->basic_type() < (int)T_OBJECT) {
4463 assert(st_off >= last_tile_end, "tiles do not overlap");
4464 assert(st_off >= last_init_end, "tiles do not overwrite inits");
4465 last_tile_end = MAX2(last_tile_end, next_init_off);
4466 } else {
4467 intptr_t st_tile_end = align_up(next_init_off, BytesPerLong);
4468 assert(st_tile_end >= last_tile_end, "inits stay with tiles");
4469 assert(st_off >= last_init_end, "inits do not overlap");
4470 last_init_end = next_init_off; // it's a non-tile
4471 }
4472 #endif //ASSERT
4473 }
4474
4475 remove_extra_zeroes(); // clear out all the zmems left over
4476 add_req(inits);
4477
4478 if (!(UseTLAB && ZeroTLAB)) {
4479 // If anything remains to be zeroed, zero it all now.
4480 zeroes_done = align_down(zeroes_done, BytesPerInt);
4481 // if it is the last unused 4 bytes of an instance, forget about it
4482 intptr_t size_limit = phase->find_intptr_t_con(size_in_bytes, max_jint);
4483 if (zeroes_done + BytesPerLong >= size_limit) {
4484 AllocateNode* alloc = allocation();
4485 assert(alloc != nullptr, "must be present");
4486 if (alloc != nullptr && alloc->Opcode() == Op_Allocate) {
4487 Node* klass_node = alloc->in(AllocateNode::KlassNode);
4488 ciKlass* k = phase->type(klass_node)->is_instklassptr()->instance_klass();
4489 if (zeroes_done == k->layout_helper())
4490 zeroes_done = size_limit;
4491 }
4492 }
4493 if (zeroes_done < size_limit) {
4494 rawmem = ClearArrayNode::clear_memory(rawctl, rawmem, rawptr,
4495 zeroes_done, size_in_bytes, phase);
4496 }
4497 }
4498
4499 set_complete(phase);
4500 return rawmem;
4501 }
4502
4503
4504 #ifdef ASSERT
4505 bool InitializeNode::stores_are_sane(PhaseValues* phase) {
4506 if (is_complete())
4507 return true; // stores could be anything at this point
4508 assert(allocation() != nullptr, "must be present");
4509 intptr_t last_off = allocation()->minimum_header_size();
4510 for (uint i = InitializeNode::RawStores; i < req(); i++) {
4511 Node* st = in(i);
4512 intptr_t st_off = get_store_offset(st, phase);
4513 if (st_off < 0) continue; // ignore dead garbage
4514 if (last_off > st_off) {
4515 tty->print_cr("*** bad store offset at %d: " INTX_FORMAT " > " INTX_FORMAT, i, last_off, st_off);
4516 this->dump(2);
4517 assert(false, "ascending store offsets");
4518 return false;
4519 }
4520 last_off = st_off + st->as_Store()->memory_size();
4521 }
4522 return true;
4523 }
4524 #endif //ASSERT
4525
4526
4527
4528
4529 //============================MergeMemNode=====================================
4530 //
4531 // SEMANTICS OF MEMORY MERGES: A MergeMem is a memory state assembled from several
4532 // contributing store or call operations. Each contributor provides the memory
4533 // state for a particular "alias type" (see Compile::alias_type). For example,
4534 // if a MergeMem has an input X for alias category #6, then any memory reference
4535 // to alias category #6 may use X as its memory state input, as an exact equivalent
4536 // to using the MergeMem as a whole.
4537 // Load<6>( MergeMem(<6>: X, ...), p ) <==> Load<6>(X,p)
4538 //
4539 // (Here, the <N> notation gives the index of the relevant adr_type.)
4540 //
4541 // In one special case (and more cases in the future), alias categories overlap.
4542 // The special alias category "Bot" (Compile::AliasIdxBot) includes all memory
4543 // states. Therefore, if a MergeMem has only one contributing input W for Bot,
4544 // it is exactly equivalent to that state W:
4545 // MergeMem(<Bot>: W) <==> W
4546 //
4547 // Usually, the merge has more than one input. In that case, where inputs
4548 // overlap (i.e., one is Bot), the narrower alias type determines the memory
4549 // state for that type, and the wider alias type (Bot) fills in everywhere else:
4550 // Load<5>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<5>(W,p)
4551 // Load<6>( MergeMem(<Bot>: W, <6>: X), p ) <==> Load<6>(X,p)
4552 //
4553 // A merge can take a "wide" memory state as one of its narrow inputs.
4554 // This simply means that the merge observes out only the relevant parts of
4555 // the wide input. That is, wide memory states arriving at narrow merge inputs
4556 // are implicitly "filtered" or "sliced" as necessary. (This is rare.)
4557 //
4558 // These rules imply that MergeMem nodes may cascade (via their <Bot> links),
4559 // and that memory slices "leak through":
4560 // MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y)) <==> MergeMem(<Bot>: W, <7>: Y)
4561 //
4562 // But, in such a cascade, repeated memory slices can "block the leak":
4563 // MergeMem(<Bot>: MergeMem(<Bot>: W, <7>: Y), <7>: Y') <==> MergeMem(<Bot>: W, <7>: Y')
4564 //
4565 // In the last example, Y is not part of the combined memory state of the
4566 // outermost MergeMem. The system must, of course, prevent unschedulable
4567 // memory states from arising, so you can be sure that the state Y is somehow
4568 // a precursor to state Y'.
4569 //
4570 //
4571 // REPRESENTATION OF MEMORY MERGES: The indexes used to address the Node::in array
4572 // of each MergeMemNode array are exactly the numerical alias indexes, including
4573 // but not limited to AliasIdxTop, AliasIdxBot, and AliasIdxRaw. The functions
4574 // Compile::alias_type (and kin) produce and manage these indexes.
4575 //
4576 // By convention, the value of in(AliasIdxTop) (i.e., in(1)) is always the top node.
4577 // (Note that this provides quick access to the top node inside MergeMem methods,
4578 // without the need to reach out via TLS to Compile::current.)
4579 //
4580 // As a consequence of what was just described, a MergeMem that represents a full
4581 // memory state has an edge in(AliasIdxBot) which is a "wide" memory state,
4582 // containing all alias categories.
4583 //
4584 // MergeMem nodes never (?) have control inputs, so in(0) is null.
4585 //
4586 // All other edges in(N) (including in(AliasIdxRaw), which is in(3)) are either
4587 // a memory state for the alias type <N>, or else the top node, meaning that
4588 // there is no particular input for that alias type. Note that the length of
4589 // a MergeMem is variable, and may be extended at any time to accommodate new
4590 // memory states at larger alias indexes. When merges grow, they are of course
4591 // filled with "top" in the unused in() positions.
4592 //
4593 // This use of top is named "empty_memory()", or "empty_mem" (no-memory) as a variable.
4594 // (Top was chosen because it works smoothly with passes like GCM.)
4595 //
4596 // For convenience, we hardwire the alias index for TypeRawPtr::BOTTOM. (It is
4597 // the type of random VM bits like TLS references.) Since it is always the
4598 // first non-Bot memory slice, some low-level loops use it to initialize an
4599 // index variable: for (i = AliasIdxRaw; i < req(); i++).
4600 //
4601 //
4602 // ACCESSORS: There is a special accessor MergeMemNode::base_memory which returns
4603 // the distinguished "wide" state. The accessor MergeMemNode::memory_at(N) returns
4604 // the memory state for alias type <N>, or (if there is no particular slice at <N>,
4605 // it returns the base memory. To prevent bugs, memory_at does not accept <Top>
4606 // or <Bot> indexes. The iterator MergeMemStream provides robust iteration over
4607 // MergeMem nodes or pairs of such nodes, ensuring that the non-top edges are visited.
4608 //
4609 // %%%% We may get rid of base_memory as a separate accessor at some point; it isn't
4610 // really that different from the other memory inputs. An abbreviation called
4611 // "bot_memory()" for "memory_at(AliasIdxBot)" would keep code tidy.
4612 //
4613 //
4614 // PARTIAL MEMORY STATES: During optimization, MergeMem nodes may arise that represent
4615 // partial memory states. When a Phi splits through a MergeMem, the copy of the Phi
4616 // that "emerges though" the base memory will be marked as excluding the alias types
4617 // of the other (narrow-memory) copies which "emerged through" the narrow edges:
4618 //
4619 // Phi<Bot>(U, MergeMem(<Bot>: W, <8>: Y))
4620 // ==Ideal=> MergeMem(<Bot>: Phi<Bot-8>(U, W), Phi<8>(U, Y))
4621 //
4622 // This strange "subtraction" effect is necessary to ensure IGVN convergence.
4623 // (It is currently unimplemented.) As you can see, the resulting merge is
4624 // actually a disjoint union of memory states, rather than an overlay.
4625 //
4626
4627 //------------------------------MergeMemNode-----------------------------------
4628 Node* MergeMemNode::make_empty_memory() {
4629 Node* empty_memory = (Node*) Compile::current()->top();
4630 assert(empty_memory->is_top(), "correct sentinel identity");
4631 return empty_memory;
4632 }
4633
4634 MergeMemNode::MergeMemNode(Node *new_base) : Node(1+Compile::AliasIdxRaw) {
4635 init_class_id(Class_MergeMem);
4636 // all inputs are nullified in Node::Node(int)
4637 // set_input(0, nullptr); // no control input
4638
4639 // Initialize the edges uniformly to top, for starters.
4640 Node* empty_mem = make_empty_memory();
4641 for (uint i = Compile::AliasIdxTop; i < req(); i++) {
4642 init_req(i,empty_mem);
4643 }
4644 assert(empty_memory() == empty_mem, "");
4645
4646 if( new_base != nullptr && new_base->is_MergeMem() ) {
4647 MergeMemNode* mdef = new_base->as_MergeMem();
4648 assert(mdef->empty_memory() == empty_mem, "consistent sentinels");
4649 for (MergeMemStream mms(this, mdef); mms.next_non_empty2(); ) {
4650 mms.set_memory(mms.memory2());
4651 }
4652 assert(base_memory() == mdef->base_memory(), "");
4653 } else {
4654 set_base_memory(new_base);
4655 }
4656 }
4657
4658 // Make a new, untransformed MergeMem with the same base as 'mem'.
4659 // If mem is itself a MergeMem, populate the result with the same edges.
4660 MergeMemNode* MergeMemNode::make(Node* mem) {
4661 return new MergeMemNode(mem);
4662 }
4663
4664 //------------------------------cmp--------------------------------------------
4665 uint MergeMemNode::hash() const { return NO_HASH; }
4666 bool MergeMemNode::cmp( const Node &n ) const {
4667 return (&n == this); // Always fail except on self
4668 }
4669
4670 //------------------------------Identity---------------------------------------
4671 Node* MergeMemNode::Identity(PhaseGVN* phase) {
4672 // Identity if this merge point does not record any interesting memory
4673 // disambiguations.
4674 Node* base_mem = base_memory();
4675 Node* empty_mem = empty_memory();
4676 if (base_mem != empty_mem) { // Memory path is not dead?
4677 for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
4678 Node* mem = in(i);
4679 if (mem != empty_mem && mem != base_mem) {
4680 return this; // Many memory splits; no change
4681 }
4682 }
4683 }
4684 return base_mem; // No memory splits; ID on the one true input
4685 }
4686
4687 //------------------------------Ideal------------------------------------------
4688 // This method is invoked recursively on chains of MergeMem nodes
4689 Node *MergeMemNode::Ideal(PhaseGVN *phase, bool can_reshape) {
4690 // Remove chain'd MergeMems
4691 //
4692 // This is delicate, because the each "in(i)" (i >= Raw) is interpreted
4693 // relative to the "in(Bot)". Since we are patching both at the same time,
4694 // we have to be careful to read each "in(i)" relative to the old "in(Bot)",
4695 // but rewrite each "in(i)" relative to the new "in(Bot)".
4696 Node *progress = nullptr;
4697
4698
4699 Node* old_base = base_memory();
4700 Node* empty_mem = empty_memory();
4701 if (old_base == empty_mem)
4702 return nullptr; // Dead memory path.
4703
4704 MergeMemNode* old_mbase;
4705 if (old_base != nullptr && old_base->is_MergeMem())
4706 old_mbase = old_base->as_MergeMem();
4707 else
4708 old_mbase = nullptr;
4709 Node* new_base = old_base;
4710
4711 // simplify stacked MergeMems in base memory
4712 if (old_mbase) new_base = old_mbase->base_memory();
4713
4714 // the base memory might contribute new slices beyond my req()
4715 if (old_mbase) grow_to_match(old_mbase);
4716
4717 // Note: We do not call verify_sparse on entry, because inputs
4718 // can normalize to the base_memory via subsume_node or similar
4719 // mechanisms. This method repairs that damage.
4720
4721 assert(!old_mbase || old_mbase->is_empty_memory(empty_mem), "consistent sentinels");
4722
4723 // Look at each slice.
4724 for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
4725 Node* old_in = in(i);
4726 // calculate the old memory value
4727 Node* old_mem = old_in;
4728 if (old_mem == empty_mem) old_mem = old_base;
4729 assert(old_mem == memory_at(i), "");
4730
4731 // maybe update (reslice) the old memory value
4732
4733 // simplify stacked MergeMems
4734 Node* new_mem = old_mem;
4735 MergeMemNode* old_mmem;
4736 if (old_mem != nullptr && old_mem->is_MergeMem())
4737 old_mmem = old_mem->as_MergeMem();
4738 else
4739 old_mmem = nullptr;
4740 if (old_mmem == this) {
4741 // This can happen if loops break up and safepoints disappear.
4742 // A merge of BotPtr (default) with a RawPtr memory derived from a
4743 // safepoint can be rewritten to a merge of the same BotPtr with
4744 // the BotPtr phi coming into the loop. If that phi disappears
4745 // also, we can end up with a self-loop of the mergemem.
4746 // In general, if loops degenerate and memory effects disappear,
4747 // a mergemem can be left looking at itself. This simply means
4748 // that the mergemem's default should be used, since there is
4749 // no longer any apparent effect on this slice.
4750 // Note: If a memory slice is a MergeMem cycle, it is unreachable
4751 // from start. Update the input to TOP.
4752 new_mem = (new_base == this || new_base == empty_mem)? empty_mem : new_base;
4753 }
4754 else if (old_mmem != nullptr) {
4755 new_mem = old_mmem->memory_at(i);
4756 }
4757 // else preceding memory was not a MergeMem
4758
4759 // maybe store down a new value
4760 Node* new_in = new_mem;
4761 if (new_in == new_base) new_in = empty_mem;
4762
4763 if (new_in != old_in) {
4764 // Warning: Do not combine this "if" with the previous "if"
4765 // A memory slice might have be be rewritten even if it is semantically
4766 // unchanged, if the base_memory value has changed.
4767 set_req_X(i, new_in, phase);
4768 progress = this; // Report progress
4769 }
4770 }
4771
4772 if (new_base != old_base) {
4773 set_req_X(Compile::AliasIdxBot, new_base, phase);
4774 // Don't use set_base_memory(new_base), because we need to update du.
4775 assert(base_memory() == new_base, "");
4776 progress = this;
4777 }
4778
4779 if( base_memory() == this ) {
4780 // a self cycle indicates this memory path is dead
4781 set_req(Compile::AliasIdxBot, empty_mem);
4782 }
4783
4784 // Resolve external cycles by calling Ideal on a MergeMem base_memory
4785 // Recursion must occur after the self cycle check above
4786 if( base_memory()->is_MergeMem() ) {
4787 MergeMemNode *new_mbase = base_memory()->as_MergeMem();
4788 Node *m = phase->transform(new_mbase); // Rollup any cycles
4789 if( m != nullptr &&
4790 (m->is_top() ||
4791 (m->is_MergeMem() && m->as_MergeMem()->base_memory() == empty_mem)) ) {
4792 // propagate rollup of dead cycle to self
4793 set_req(Compile::AliasIdxBot, empty_mem);
4794 }
4795 }
4796
4797 if( base_memory() == empty_mem ) {
4798 progress = this;
4799 // Cut inputs during Parse phase only.
4800 // During Optimize phase a dead MergeMem node will be subsumed by Top.
4801 if( !can_reshape ) {
4802 for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
4803 if( in(i) != empty_mem ) { set_req(i, empty_mem); }
4804 }
4805 }
4806 }
4807
4808 if( !progress && base_memory()->is_Phi() && can_reshape ) {
4809 // Check if PhiNode::Ideal's "Split phis through memory merges"
4810 // transform should be attempted. Look for this->phi->this cycle.
4811 uint merge_width = req();
4812 if (merge_width > Compile::AliasIdxRaw) {
4813 PhiNode* phi = base_memory()->as_Phi();
4814 for( uint i = 1; i < phi->req(); ++i ) {// For all paths in
4815 if (phi->in(i) == this) {
4816 phase->is_IterGVN()->_worklist.push(phi);
4817 break;
4818 }
4819 }
4820 }
4821 }
4822
4823 assert(progress || verify_sparse(), "please, no dups of base");
4824 return progress;
4825 }
4826
4827 //-------------------------set_base_memory-------------------------------------
4828 void MergeMemNode::set_base_memory(Node *new_base) {
4829 Node* empty_mem = empty_memory();
4830 set_req(Compile::AliasIdxBot, new_base);
4831 assert(memory_at(req()) == new_base, "must set default memory");
4832 // Clear out other occurrences of new_base:
4833 if (new_base != empty_mem) {
4834 for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
4835 if (in(i) == new_base) set_req(i, empty_mem);
4836 }
4837 }
4838 }
4839
4840 //------------------------------out_RegMask------------------------------------
4841 const RegMask &MergeMemNode::out_RegMask() const {
4842 return RegMask::Empty;
4843 }
4844
4845 //------------------------------dump_spec--------------------------------------
4846 #ifndef PRODUCT
4847 void MergeMemNode::dump_spec(outputStream *st) const {
4848 st->print(" {");
4849 Node* base_mem = base_memory();
4850 for( uint i = Compile::AliasIdxRaw; i < req(); i++ ) {
4851 Node* mem = (in(i) != nullptr) ? memory_at(i) : base_mem;
4852 if (mem == base_mem) { st->print(" -"); continue; }
4853 st->print( " N%d:", mem->_idx );
4854 Compile::current()->get_adr_type(i)->dump_on(st);
4855 }
4856 st->print(" }");
4857 }
4858 #endif // !PRODUCT
4859
4860
4861 #ifdef ASSERT
4862 static bool might_be_same(Node* a, Node* b) {
4863 if (a == b) return true;
4864 if (!(a->is_Phi() || b->is_Phi())) return false;
4865 // phis shift around during optimization
4866 return true; // pretty stupid...
4867 }
4868
4869 // verify a narrow slice (either incoming or outgoing)
4870 static void verify_memory_slice(const MergeMemNode* m, int alias_idx, Node* n) {
4871 if (!VerifyAliases) return; // don't bother to verify unless requested
4872 if (VMError::is_error_reported()) return; // muzzle asserts when debugging an error
4873 if (Node::in_dump()) return; // muzzle asserts when printing
4874 assert(alias_idx >= Compile::AliasIdxRaw, "must not disturb base_memory or sentinel");
4875 assert(n != nullptr, "");
4876 // Elide intervening MergeMem's
4877 while (n->is_MergeMem()) {
4878 n = n->as_MergeMem()->memory_at(alias_idx);
4879 }
4880 Compile* C = Compile::current();
4881 const TypePtr* n_adr_type = n->adr_type();
4882 if (n == m->empty_memory()) {
4883 // Implicit copy of base_memory()
4884 } else if (n_adr_type != TypePtr::BOTTOM) {
4885 assert(n_adr_type != nullptr, "new memory must have a well-defined adr_type");
4886 assert(C->must_alias(n_adr_type, alias_idx), "new memory must match selected slice");
4887 } else {
4888 // A few places like make_runtime_call "know" that VM calls are narrow,
4889 // and can be used to update only the VM bits stored as TypeRawPtr::BOTTOM.
4890 bool expected_wide_mem = false;
4891 if (n == m->base_memory()) {
4892 expected_wide_mem = true;
4893 } else if (alias_idx == Compile::AliasIdxRaw ||
4894 n == m->memory_at(Compile::AliasIdxRaw)) {
4895 expected_wide_mem = true;
4896 } else if (!C->alias_type(alias_idx)->is_rewritable()) {
4897 // memory can "leak through" calls on channels that
4898 // are write-once. Allow this also.
4899 expected_wide_mem = true;
4900 }
4901 assert(expected_wide_mem, "expected narrow slice replacement");
4902 }
4903 }
4904 #else // !ASSERT
4905 #define verify_memory_slice(m,i,n) (void)(0) // PRODUCT version is no-op
4906 #endif
4907
4908
4909 //-----------------------------memory_at---------------------------------------
4910 Node* MergeMemNode::memory_at(uint alias_idx) const {
4911 assert(alias_idx >= Compile::AliasIdxRaw ||
4912 alias_idx == Compile::AliasIdxBot && !Compile::current()->do_aliasing(),
4913 "must avoid base_memory and AliasIdxTop");
4914
4915 // Otherwise, it is a narrow slice.
4916 Node* n = alias_idx < req() ? in(alias_idx) : empty_memory();
4917 if (is_empty_memory(n)) {
4918 // the array is sparse; empty slots are the "top" node
4919 n = base_memory();
4920 assert(Node::in_dump()
4921 || n == nullptr || n->bottom_type() == Type::TOP
4922 || n->adr_type() == nullptr // address is TOP
4923 || n->adr_type() == TypePtr::BOTTOM
4924 || n->adr_type() == TypeRawPtr::BOTTOM
4925 || !Compile::current()->do_aliasing(),
4926 "must be a wide memory");
4927 // do_aliasing == false if we are organizing the memory states manually.
4928 // See verify_memory_slice for comments on TypeRawPtr::BOTTOM.
4929 } else {
4930 // make sure the stored slice is sane
4931 #ifdef ASSERT
4932 if (VMError::is_error_reported() || Node::in_dump()) {
4933 } else if (might_be_same(n, base_memory())) {
4934 // Give it a pass: It is a mostly harmless repetition of the base.
4935 // This can arise normally from node subsumption during optimization.
4936 } else {
4937 verify_memory_slice(this, alias_idx, n);
4938 }
4939 #endif
4940 }
4941 return n;
4942 }
4943
4944 //---------------------------set_memory_at-------------------------------------
4945 void MergeMemNode::set_memory_at(uint alias_idx, Node *n) {
4946 verify_memory_slice(this, alias_idx, n);
4947 Node* empty_mem = empty_memory();
4948 if (n == base_memory()) n = empty_mem; // collapse default
4949 uint need_req = alias_idx+1;
4950 if (req() < need_req) {
4951 if (n == empty_mem) return; // already the default, so do not grow me
4952 // grow the sparse array
4953 do {
4954 add_req(empty_mem);
4955 } while (req() < need_req);
4956 }
4957 set_req( alias_idx, n );
4958 }
4959
4960
4961
4962 //--------------------------iteration_setup------------------------------------
4963 void MergeMemNode::iteration_setup(const MergeMemNode* other) {
4964 if (other != nullptr) {
4965 grow_to_match(other);
4966 // invariant: the finite support of mm2 is within mm->req()
4967 #ifdef ASSERT
4968 for (uint i = req(); i < other->req(); i++) {
4969 assert(other->is_empty_memory(other->in(i)), "slice left uncovered");
4970 }
4971 #endif
4972 }
4973 // Replace spurious copies of base_memory by top.
4974 Node* base_mem = base_memory();
4975 if (base_mem != nullptr && !base_mem->is_top()) {
4976 for (uint i = Compile::AliasIdxBot+1, imax = req(); i < imax; i++) {
4977 if (in(i) == base_mem)
4978 set_req(i, empty_memory());
4979 }
4980 }
4981 }
4982
4983 //---------------------------grow_to_match-------------------------------------
4984 void MergeMemNode::grow_to_match(const MergeMemNode* other) {
4985 Node* empty_mem = empty_memory();
4986 assert(other->is_empty_memory(empty_mem), "consistent sentinels");
4987 // look for the finite support of the other memory
4988 for (uint i = other->req(); --i >= req(); ) {
4989 if (other->in(i) != empty_mem) {
4990 uint new_len = i+1;
4991 while (req() < new_len) add_req(empty_mem);
4992 break;
4993 }
4994 }
4995 }
4996
4997 //---------------------------verify_sparse-------------------------------------
4998 #ifndef PRODUCT
4999 bool MergeMemNode::verify_sparse() const {
5000 assert(is_empty_memory(make_empty_memory()), "sane sentinel");
5001 Node* base_mem = base_memory();
5002 // The following can happen in degenerate cases, since empty==top.
5003 if (is_empty_memory(base_mem)) return true;
5004 for (uint i = Compile::AliasIdxRaw; i < req(); i++) {
5005 assert(in(i) != nullptr, "sane slice");
5006 if (in(i) == base_mem) return false; // should have been the sentinel value!
5007 }
5008 return true;
5009 }
5010
5011 bool MergeMemStream::match_memory(Node* mem, const MergeMemNode* mm, int idx) {
5012 Node* n;
5013 n = mm->in(idx);
5014 if (mem == n) return true; // might be empty_memory()
5015 n = (idx == Compile::AliasIdxBot)? mm->base_memory(): mm->memory_at(idx);
5016 if (mem == n) return true;
5017 return false;
5018 }
5019 #endif // !PRODUCT