1 /*
2 * Copyright (c) 2005, 2026, 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.
18 *
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.
22 *
23 */
24
25 #include "compiler/compileLog.hpp"
26 #include "gc/shared/collectedHeap.inline.hpp"
27 #include "gc/shared/tlab_globals.hpp"
28 #include "libadt/vectset.hpp"
29 #include "memory/universe.hpp"
30 #include "opto/addnode.hpp"
31 #include "opto/arraycopynode.hpp"
32 #include "opto/callnode.hpp"
33 #include "opto/castnode.hpp"
34 #include "opto/cfgnode.hpp"
35 #include "opto/compile.hpp"
36 #include "opto/convertnode.hpp"
37 #include "opto/graphKit.hpp"
38 #include "opto/intrinsicnode.hpp"
39 #include "opto/locknode.hpp"
40 #include "opto/loopnode.hpp"
41 #include "opto/macro.hpp"
42 #include "opto/memnode.hpp"
43 #include "opto/narrowptrnode.hpp"
44 #include "opto/node.hpp"
45 #include "opto/opaquenode.hpp"
46 #include "opto/phaseX.hpp"
47 #include "opto/reachability.hpp"
48 #include "opto/rootnode.hpp"
49 #include "opto/runtime.hpp"
50 #include "opto/subnode.hpp"
51 #include "opto/subtypenode.hpp"
52 #include "opto/type.hpp"
53 #include "prims/jvmtiExport.hpp"
54 #include "runtime/continuation.hpp"
55 #include "runtime/sharedRuntime.hpp"
56 #include "utilities/globalDefinitions.hpp"
57 #include "utilities/macros.hpp"
58 #include "utilities/powerOfTwo.hpp"
59 #if INCLUDE_G1GC
60 #include "gc/g1/g1ThreadLocalData.hpp"
61 #endif // INCLUDE_G1GC
62
63
64 //
65 // Replace any references to "oldref" in inputs to "use" with "newref".
66 // Returns the number of replacements made.
67 //
68 int PhaseMacroExpand::replace_input(Node *use, Node *oldref, Node *newref) {
69 int nreplacements = 0;
70 uint req = use->req();
71 for (uint j = 0; j < use->len(); j++) {
72 Node *uin = use->in(j);
73 if (uin == oldref) {
74 if (j < req)
75 use->set_req(j, newref);
76 else
77 use->set_prec(j, newref);
78 nreplacements++;
79 } else if (j >= req && uin == nullptr) {
80 break;
81 }
82 }
83 return nreplacements;
84 }
85
86 void PhaseMacroExpand::migrate_outs(Node *old, Node *target) {
87 assert(old != nullptr, "sanity");
88 for (DUIterator_Fast imax, i = old->fast_outs(imax); i < imax; i++) {
89 Node* use = old->fast_out(i);
90 _igvn.rehash_node_delayed(use);
91 imax -= replace_input(use, old, target);
92 // back up iterator
93 --i;
94 }
95 assert(old->outcnt() == 0, "all uses must be deleted");
96 }
97
98 Node* PhaseMacroExpand::opt_bits_test(Node* ctrl, Node* region, int edge, Node* word) {
99 Node* cmp = word;
100 Node* bol = transform_later(new BoolNode(cmp, BoolTest::ne));
101 IfNode* iff = new IfNode( ctrl, bol, PROB_MIN, COUNT_UNKNOWN );
102 transform_later(iff);
103
104 // Fast path taken.
105 Node *fast_taken = transform_later(new IfFalseNode(iff));
106
107 // Fast path not-taken, i.e. slow path
108 Node *slow_taken = transform_later(new IfTrueNode(iff));
109
110 region->init_req(edge, fast_taken); // Capture fast-control
111 return slow_taken;
112 }
113
114 //--------------------copy_predefined_input_for_runtime_call--------------------
115 void PhaseMacroExpand::copy_predefined_input_for_runtime_call(Node * ctrl, CallNode* oldcall, CallNode* call) {
116 // Set fixed predefined input arguments
117 call->init_req( TypeFunc::Control, ctrl );
118 call->init_req( TypeFunc::I_O , oldcall->in( TypeFunc::I_O) );
119 call->init_req( TypeFunc::Memory , oldcall->in( TypeFunc::Memory ) ); // ?????
120 call->init_req( TypeFunc::ReturnAdr, oldcall->in( TypeFunc::ReturnAdr ) );
121 call->init_req( TypeFunc::FramePtr, oldcall->in( TypeFunc::FramePtr ) );
122 }
123
124 //------------------------------make_slow_call---------------------------------
125 CallNode* PhaseMacroExpand::make_slow_call(CallNode *oldcall, const TypeFunc* slow_call_type,
126 address slow_call, const char* leaf_name, Node* slow_path,
127 Node* parm0, Node* parm1, Node* parm2) {
128
129 // Slow-path call
130 CallNode *call = leaf_name
131 ? (CallNode*)new CallLeafNode ( slow_call_type, slow_call, leaf_name, TypeRawPtr::BOTTOM )
132 : (CallNode*)new CallStaticJavaNode( slow_call_type, slow_call, OptoRuntime::stub_name(slow_call), TypeRawPtr::BOTTOM );
133
134 // Slow path call has no side-effects, uses few values
135 copy_predefined_input_for_runtime_call(slow_path, oldcall, call );
136 if (parm0 != nullptr) call->init_req(TypeFunc::Parms+0, parm0);
137 if (parm1 != nullptr) call->init_req(TypeFunc::Parms+1, parm1);
138 if (parm2 != nullptr) call->init_req(TypeFunc::Parms+2, parm2);
139 call->copy_call_debug_info(&_igvn, oldcall);
140 call->set_cnt(PROB_UNLIKELY_MAG(4)); // Same effect as RC_UNCOMMON.
141 _igvn.replace_node(oldcall, call);
142 transform_later(call);
143
144 return call;
145 }
146
147 void PhaseMacroExpand::eliminate_gc_barrier(Node* p2x) {
148 BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
149 bs->eliminate_gc_barrier(this, p2x);
150 #ifndef PRODUCT
151 if (PrintOptoStatistics) {
152 AtomicAccess::inc(&PhaseMacroExpand::_GC_barriers_removed_counter);
153 }
154 #endif
155 }
156
157 // Search for a memory operation for the specified memory slice.
158 static Node *scan_mem_chain(Node *mem, int alias_idx, int offset, Node *start_mem, Node *alloc, PhaseGVN *phase) {
159 Node *orig_mem = mem;
160 Node *alloc_mem = alloc->as_Allocate()->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
161 assert(alloc_mem != nullptr, "Allocation without a memory projection.");
162 const TypeOopPtr *tinst = phase->C->get_adr_type(alias_idx)->isa_oopptr();
163 while (true) {
164 if (mem == alloc_mem || mem == start_mem ) {
165 return mem; // hit one of our sentinels
166 } else if (mem->is_MergeMem()) {
167 mem = mem->as_MergeMem()->memory_at(alias_idx);
168 } else if (mem->is_Proj() && mem->as_Proj()->_con == TypeFunc::Memory) {
169 Node *in = mem->in(0);
170 // we can safely skip over safepoints, calls, locks and membars because we
171 // already know that the object is safe to eliminate.
172 if (in->is_Initialize() && in->as_Initialize()->allocation() == alloc) {
173 return in;
174 } else if (in->is_Call()) {
175 CallNode *call = in->as_Call();
176 if (call->may_modify(tinst, phase)) {
177 assert(call->is_ArrayCopy(), "ArrayCopy is the only call node that doesn't make allocation escape");
178 if (call->as_ArrayCopy()->modifies(offset, offset, phase, false)) {
179 return in;
180 }
181 }
182 mem = in->in(TypeFunc::Memory);
183 } else if (in->is_MemBar()) {
184 ArrayCopyNode* ac = nullptr;
185 if (ArrayCopyNode::may_modify(tinst, in->as_MemBar(), phase, ac)) {
186 if (ac != nullptr) {
187 assert(ac->is_clonebasic(), "Only basic clone is a non escaping clone");
188 return ac;
189 }
190 }
191 mem = in->in(TypeFunc::Memory);
192 } else {
193 #ifdef ASSERT
194 in->dump();
195 mem->dump();
196 assert(false, "unexpected projection");
197 #endif
198 }
199 } else if (mem->is_Store()) {
200 const TypePtr* atype = mem->as_Store()->adr_type();
201 int adr_idx = phase->C->get_alias_index(atype);
202 if (adr_idx == alias_idx) {
203 assert(atype->isa_oopptr(), "address type must be oopptr");
204 int adr_offset = atype->offset();
205 uint adr_iid = atype->is_oopptr()->instance_id();
206 // Array elements references have the same alias_idx
207 // but different offset and different instance_id.
208 if (adr_offset == offset && adr_iid == alloc->_idx) {
209 return mem;
210 }
211 } else {
212 assert(adr_idx == Compile::AliasIdxRaw, "address must match or be raw");
213 }
214 mem = mem->in(MemNode::Memory);
215 } else if (mem->is_ClearArray()) {
216 if (!ClearArrayNode::step_through(&mem, alloc->_idx, phase)) {
217 // Can not bypass initialization of the instance
218 // we are looking.
219 DEBUG_ONLY(intptr_t offset;)
220 assert(alloc == AllocateNode::Ideal_allocation(mem->in(3), phase, offset), "sanity");
221 InitializeNode* init = alloc->as_Allocate()->initialization();
222 // We are looking for stored value, return Initialize node
223 // or memory edge from Allocate node.
224 if (init != nullptr) {
225 return init;
226 } else {
227 return alloc->in(TypeFunc::Memory); // It will produce zero value (see callers).
228 }
229 }
230 // Otherwise skip it (the call updated 'mem' value).
231 } else if (mem->Opcode() == Op_SCMemProj) {
232 mem = mem->in(0);
233 Node* adr = nullptr;
234 if (mem->is_LoadStore()) {
235 adr = mem->in(MemNode::Address);
236 } else {
237 assert(mem->Opcode() == Op_EncodeISOArray ||
238 mem->Opcode() == Op_StrCompressedCopy, "sanity");
239 adr = mem->in(3); // Destination array
240 }
241 const TypePtr* atype = adr->bottom_type()->is_ptr();
242 int adr_idx = phase->C->get_alias_index(atype);
243 if (adr_idx == alias_idx) {
244 DEBUG_ONLY(mem->dump();)
245 assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
246 return nullptr;
247 }
248 mem = mem->in(MemNode::Memory);
249 } else if (mem->Opcode() == Op_StrInflatedCopy) {
250 Node* adr = mem->in(3); // Destination array
251 const TypePtr* atype = adr->bottom_type()->is_ptr();
252 int adr_idx = phase->C->get_alias_index(atype);
253 if (adr_idx == alias_idx) {
254 DEBUG_ONLY(mem->dump();)
255 assert(false, "Object is not scalar replaceable if a StrInflatedCopy node accesses its field");
256 return nullptr;
257 }
258 mem = mem->in(MemNode::Memory);
259 } else {
260 return mem;
261 }
262 assert(mem != orig_mem, "dead memory loop");
263 }
264 }
265
266 // Determine if there is an interfering store between a rematerialization load and an arraycopy that is in the process
267 // of being elided. Starting from the given rematerialization load this method starts a BFS traversal upwards through
268 // the memory graph towards the provided ArrayCopyNode. For every node encountered on the traversal, check that it is
269 // independent from the provided rematerialization. Returns false if every node on the traversal is independent and
270 // true otherwise.
271 bool has_interfering_store(const ArrayCopyNode* ac, LoadNode* load, PhaseGVN* phase) {
272 assert(ac != nullptr && load != nullptr, "sanity");
273 AccessAnalyzer acc(phase, load);
274 ResourceMark rm;
275 Unique_Node_List to_visit;
276 to_visit.push(load->in(MemNode::Memory));
277
278 for (uint worklist_idx = 0; worklist_idx < to_visit.size(); worklist_idx++) {
279 Node* mem = to_visit.at(worklist_idx);
280
281 if (mem->is_Proj() && mem->in(0) == ac) {
282 // Reached the target, so visit what is left on the worklist.
283 continue;
284 }
285
286 if (mem->is_Phi()) {
287 assert(mem->bottom_type() == Type::MEMORY, "do not leave memory graph");
288 // Add all non-control inputs of phis to be visited.
289 for (uint phi_in = 1; phi_in < mem->len(); phi_in++) {
290 Node* input = mem->in(phi_in);
291 if (input != nullptr) {
292 to_visit.push(input);
293 }
294 }
295 continue;
296 }
297
298 AccessAnalyzer::AccessIndependence ind = acc.detect_access_independence(mem);
299 if (ind.independent) {
300 to_visit.push(ind.mem);
301 } else {
302 return true;
303 }
304 }
305 // Did not find modification of source element in memory graph.
306 return false;
307 }
308
309 // Generate loads from source of the arraycopy for fields of destination needed at a deoptimization point.
310 // Returns nullptr if the load cannot be created because the arraycopy is not suitable for elimination
311 // (e.g. copy inside the array with non-constant offsets) or the inputs do not match our assumptions (e.g.
312 // the arraycopy does not actually write something at the provided offset).
313 Node* PhaseMacroExpand::make_arraycopy_load(ArrayCopyNode* ac, intptr_t offset, Node* ctl, Node* mem, BasicType ft, const Type* ftype, AllocateNode* alloc) {
314 assert((ctl == ac->control() && mem == ac->memory()) != (mem != ac->memory() && ctl->is_Proj() && ctl->as_Proj()->is_uncommon_trap_proj()),
315 "Either the control and memory are the same as for the arraycopy or they are pinned in an uncommon trap.");
316 BasicType bt = ft;
317 const Type *type = ftype;
318 if (ft == T_NARROWOOP) {
319 bt = T_OBJECT;
320 type = ftype->make_oopptr();
321 }
322 Node* base = ac->in(ArrayCopyNode::Src);
323 Node* adr = nullptr;
324 const TypePtr* adr_type = nullptr;
325
326 if (ac->is_clonebasic()) {
327 assert(ac->in(ArrayCopyNode::Src) != ac->in(ArrayCopyNode::Dest), "clone source equals destination");
328 adr = _igvn.transform(AddPNode::make_with_base(base, _igvn.MakeConX(offset)));
329 adr_type = _igvn.type(base)->is_ptr()->add_offset(offset);
330 } else {
331 if (!ac->modifies(offset, offset, &_igvn, true)) {
332 // If the arraycopy does not copy to this offset, we cannot generate a rematerialization load for it.
333 return nullptr;
334 }
335 assert(ac->in(ArrayCopyNode::Dest) == alloc->result_cast(), "arraycopy destination should be allocation's result");
336 uint shift = exact_log2(type2aelembytes(bt));
337 Node* src_pos = ac->in(ArrayCopyNode::SrcPos);
338 Node* dest_pos = ac->in(ArrayCopyNode::DestPos);
339 const TypeInt* src_pos_t = _igvn.type(src_pos)->is_int();
340 const TypeInt* dest_pos_t = _igvn.type(dest_pos)->is_int();
341
342 if (src_pos_t->is_con() && dest_pos_t->is_con()) {
343 intptr_t off = ((src_pos_t->get_con() - dest_pos_t->get_con()) << shift) + offset;
344 adr = _igvn.transform(AddPNode::make_with_base(base, _igvn.MakeConX(off)));
345 adr_type = _igvn.type(base)->is_ptr()->add_offset(off);
346 if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
347 // Don't emit a new load from src if src == dst but try to get the value from memory instead
348 return value_from_mem(ac, ctl, ft, ftype, adr_type->isa_oopptr(), alloc);
349 }
350 } else {
351 Node* diff = _igvn.transform(new SubINode(ac->in(ArrayCopyNode::SrcPos), ac->in(ArrayCopyNode::DestPos)));
352 #ifdef _LP64
353 diff = _igvn.transform(new ConvI2LNode(diff));
354 #endif
355 diff = _igvn.transform(new LShiftXNode(diff, _igvn.intcon(shift)));
356
357 Node* off = _igvn.transform(new AddXNode(_igvn.MakeConX(offset), diff));
358 adr = _igvn.transform(AddPNode::make_with_base(base, off));
359 adr_type = _igvn.type(base)->is_ptr()->add_offset(Type::OffsetBot);
360 if (ac->in(ArrayCopyNode::Src) == ac->in(ArrayCopyNode::Dest)) {
361 // Non constant offset in the array: we can't statically
362 // determine the value
363 return nullptr;
364 }
365 }
366 }
367 assert(adr != nullptr && adr_type != nullptr, "sanity");
368
369 // Create the rematerialization load ...
370 MergeMemNode* mergemem = _igvn.transform(MergeMemNode::make(mem))->as_MergeMem();
371 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
372 Node* res = ArrayCopyNode::load(bs, &_igvn, ctl, mergemem, adr, adr_type, type, bt);
373 assert(res != nullptr, "load should have been created");
374
375 // ... and ensure that pinning the rematerialization load inside the uncommon path is safe.
376 if (mem != ac->memory() && ctl->is_Proj() && ctl->as_Proj()->is_uncommon_trap_proj() && res->is_Load() &&
377 has_interfering_store(ac, res->as_Load(), &_igvn)) {
378 // Not safe: use control and memory from the arraycopy to ensure correct memory state.
379 _igvn.remove_dead_node(res, PhaseIterGVN::NodeOrigin::Graph); // Clean up the unusable rematerialization load.
380 return make_arraycopy_load(ac, offset, ac->control(), ac->memory(), ft, ftype, alloc);
381 }
382
383 if (ftype->isa_narrowoop()) {
384 // PhaseMacroExpand::scalar_replacement adds DecodeN nodes
385 res = _igvn.transform(new EncodePNode(res, ftype));
386 }
387 return res;
388 }
389
390 //
391 // Given a Memory Phi, compute a value Phi containing the values from stores
392 // on the input paths.
393 // Note: this function is recursive, its depth is limited by the "level" argument
394 // Returns the computed Phi, or null if it cannot compute it.
395 Node *PhaseMacroExpand::value_from_mem_phi(Node *mem, BasicType ft, const Type *phi_type, const TypeOopPtr *adr_t, AllocateNode *alloc, Node_Stack *value_phis, int level) {
396 assert(mem->is_Phi(), "sanity");
397 int alias_idx = C->get_alias_index(adr_t);
398 int offset = adr_t->offset();
399 int instance_id = adr_t->instance_id();
400
401 // Check if an appropriate value phi already exists.
402 Node* region = mem->in(0);
403 for (DUIterator_Fast kmax, k = region->fast_outs(kmax); k < kmax; k++) {
404 Node* phi = region->fast_out(k);
405 if (phi->is_Phi() && phi != mem &&
406 phi->as_Phi()->is_same_inst_field(phi_type, (int)mem->_idx, instance_id, alias_idx, offset)) {
407 return phi;
408 }
409 }
410 // Check if an appropriate new value phi already exists.
411 Node* new_phi = value_phis->find(mem->_idx);
412 if (new_phi != nullptr)
413 return new_phi;
414
415 if (level <= 0) {
416 return nullptr; // Give up: phi tree too deep
417 }
418 Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
419 Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
420 assert(alloc_mem != nullptr, "Allocation without a memory projection.");
421
422 uint length = mem->req();
423 GrowableArray <Node *> values(length, length, nullptr);
424
425 // create a new Phi for the value
426 PhiNode *phi = new PhiNode(mem->in(0), phi_type, nullptr, mem->_idx, instance_id, alias_idx, offset);
427 transform_later(phi);
428 value_phis->push(phi, mem->_idx);
429
430 for (uint j = 1; j < length; j++) {
431 Node *in = mem->in(j);
432 if (in == nullptr || in->is_top()) {
433 values.at_put(j, in);
434 } else {
435 Node *val = scan_mem_chain(in, alias_idx, offset, start_mem, alloc, &_igvn);
436 if (val == start_mem || val == alloc_mem) {
437 // hit a sentinel, return appropriate 0 value
438 values.at_put(j, _igvn.zerocon(ft));
439 continue;
440 }
441 if (val->is_Initialize()) {
442 val = val->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
443 }
444 if (val == nullptr) {
445 return nullptr; // can't find a value on this path
446 }
447 if (val == mem) {
448 values.at_put(j, mem);
449 } else if (val->is_Store()) {
450 Node* n = val->in(MemNode::ValueIn);
451 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
452 n = bs->step_over_gc_barrier(n);
453 if (is_subword_type(ft)) {
454 n = Compile::narrow_value(ft, n, phi_type, &_igvn, true);
455 }
456 values.at_put(j, n);
457 } else if(val->is_Proj() && val->in(0) == alloc) {
458 values.at_put(j, _igvn.zerocon(ft));
459 } else if (val->is_Phi()) {
460 val = value_from_mem_phi(val, ft, phi_type, adr_t, alloc, value_phis, level-1);
461 if (val == nullptr) {
462 return nullptr;
463 }
464 values.at_put(j, val);
465 } else if (val->Opcode() == Op_SCMemProj) {
466 assert(val->in(0)->is_LoadStore() ||
467 val->in(0)->Opcode() == Op_EncodeISOArray ||
468 val->in(0)->Opcode() == Op_StrCompressedCopy, "sanity");
469 assert(false, "Object is not scalar replaceable if a LoadStore node accesses its field");
470 return nullptr;
471 } else if (val->is_ArrayCopy()) {
472 Node* res = make_arraycopy_load(val->as_ArrayCopy(), offset, val->in(0), val->in(TypeFunc::Memory), ft, phi_type, alloc);
473 if (res == nullptr) {
474 return nullptr;
475 }
476 values.at_put(j, res);
477 } else if (val->is_top()) {
478 // This indicates that this path into the phi is dead. Top will eventually also propagate into the Region.
479 // IGVN will clean this up later.
480 values.at_put(j, val);
481 } else {
482 DEBUG_ONLY( val->dump(); )
483 assert(false, "unknown node on this path");
484 return nullptr; // unknown node on this path
485 }
486 }
487 }
488 // Set Phi's inputs
489 for (uint j = 1; j < length; j++) {
490 if (values.at(j) == mem) {
491 phi->init_req(j, phi);
492 } else {
493 phi->init_req(j, values.at(j));
494 }
495 }
496 return phi;
497 }
498
499 // Search the last value stored into the object's field.
500 Node* PhaseMacroExpand::value_from_mem(Node* origin, Node* ctl, BasicType ft, const Type* ftype, const TypeOopPtr* adr_t, AllocateNode* alloc) {
501 assert(adr_t->is_known_instance_field(), "instance required");
502 int instance_id = adr_t->instance_id();
503 assert((uint)instance_id == alloc->_idx, "wrong allocation");
504
505 int alias_idx = C->get_alias_index(adr_t);
506 int offset = adr_t->offset();
507 Node* orig_mem = origin->in(TypeFunc::Memory);
508 Node *start_mem = C->start()->proj_out_or_null(TypeFunc::Memory);
509 Node *alloc_ctrl = alloc->in(TypeFunc::Control);
510 Node *alloc_mem = alloc->proj_out_or_null(TypeFunc::Memory, /*io_use:*/false);
511 assert(alloc_mem != nullptr, "Allocation without a memory projection.");
512 VectorSet visited;
513
514 bool done = orig_mem == alloc_mem;
515 Node *mem = orig_mem;
516 while (!done) {
517 if (visited.test_set(mem->_idx)) {
518 return nullptr; // found a loop, give up
519 }
520 mem = scan_mem_chain(mem, alias_idx, offset, start_mem, alloc, &_igvn);
521 if (mem == start_mem || mem == alloc_mem) {
522 done = true; // hit a sentinel, return appropriate 0 value
523 } else if (mem->is_Initialize()) {
524 mem = mem->as_Initialize()->find_captured_store(offset, type2aelembytes(ft), &_igvn);
525 if (mem == nullptr) {
526 done = true; // Something go wrong.
527 } else if (mem->is_Store()) {
528 const TypePtr* atype = mem->as_Store()->adr_type();
529 assert(C->get_alias_index(atype) == Compile::AliasIdxRaw, "store is correct memory slice");
530 done = true;
531 }
532 } else if (mem->is_Store()) {
533 const TypeOopPtr* atype = mem->as_Store()->adr_type()->isa_oopptr();
534 assert(atype != nullptr, "address type must be oopptr");
535 assert(C->get_alias_index(atype) == alias_idx &&
536 atype->is_known_instance_field() && atype->offset() == offset &&
537 atype->instance_id() == instance_id, "store is correct memory slice");
538 done = true;
539 } else if (mem->is_Phi()) {
540 // try to find a phi's unique input
541 Node *unique_input = nullptr;
542 Node *top = C->top();
543 for (uint i = 1; i < mem->req(); i++) {
544 Node *n = scan_mem_chain(mem->in(i), alias_idx, offset, start_mem, alloc, &_igvn);
545 if (n == nullptr || n == top || n == mem) {
546 continue;
547 } else if (unique_input == nullptr) {
548 unique_input = n;
549 } else if (unique_input != n) {
550 unique_input = top;
551 break;
552 }
553 }
554 if (unique_input != nullptr && unique_input != top) {
555 mem = unique_input;
556 } else {
557 done = true;
558 }
559 } else if (mem->is_ArrayCopy()) {
560 done = true;
561 } else if (mem->is_top()) {
562 // The slice is on a dead path. Returning nullptr would lead to elimination
563 // bailout, but we want to prevent that. Just forwarding the top is also legal,
564 // and IGVN can just clean things up, and remove whatever receives top.
565 return mem;
566 } else {
567 DEBUG_ONLY( mem->dump(); )
568 assert(false, "unexpected node");
569 }
570 }
571 if (mem != nullptr) {
572 if (mem == start_mem || mem == alloc_mem) {
573 // hit a sentinel, return appropriate 0 value
574 return _igvn.zerocon(ft);
575 } else if (mem->is_Store()) {
576 Node* n = mem->in(MemNode::ValueIn);
577 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
578 n = bs->step_over_gc_barrier(n);
579 return n;
580 } else if (mem->is_Phi()) {
581 // attempt to produce a Phi reflecting the values on the input paths of the Phi
582 Node_Stack value_phis(8);
583 Node* phi = value_from_mem_phi(mem, ft, ftype, adr_t, alloc, &value_phis, ValueSearchLimit);
584 if (phi != nullptr) {
585 return phi;
586 } else {
587 // Kill all new Phis
588 while(value_phis.is_nonempty()) {
589 Node* n = value_phis.node();
590 _igvn.replace_node(n, C->top());
591 value_phis.pop();
592 }
593 }
594 } else if (mem->is_ArrayCopy()) {
595 // Rematerialize the scalar-replaced array. If possible, pin the loads to the uncommon path of the uncommon trap.
596 // Check for each element of the source array, whether it was modified. If not, pin both memory and control to
597 // the uncommon path. Otherwise, use the control and memory state of the arraycopy. Control and memory state must
598 // come from the same source to prevent anti-dependence problems in the backend.
599 ArrayCopyNode* ac = mem->as_ArrayCopy();
600 Node* ac_ctl = ac->control();
601 Node* ac_mem = ac->memory();
602 if (ctl->is_Proj() && ctl->as_Proj()->is_uncommon_trap_proj()) {
603 // pin the loads in the uncommon trap path
604 ac_ctl = ctl;
605 ac_mem = orig_mem;
606 }
607 return make_arraycopy_load(ac, offset, ac_ctl, ac_mem, ft, ftype, alloc);
608 }
609 }
610 // Something went wrong.
611 return nullptr;
612 }
613
614 // Check the possibility of scalar replacement.
615 bool PhaseMacroExpand::can_eliminate_allocation(PhaseIterGVN* igvn, AllocateNode *alloc, GrowableArray <SafePointNode *>* safepoints) {
616 // Scan the uses of the allocation to check for anything that would
617 // prevent us from eliminating it.
618 NOT_PRODUCT( const char* fail_eliminate = nullptr; )
619 DEBUG_ONLY( Node* disq_node = nullptr; )
620 bool can_eliminate = true;
621 bool reduce_merge_precheck = (safepoints == nullptr);
622
623 Node* res = alloc->result_cast();
624 const TypeOopPtr* res_type = nullptr;
625 if (res == nullptr) {
626 // All users were eliminated.
627 } else if (!res->is_CheckCastPP()) {
628 NOT_PRODUCT(fail_eliminate = "Allocation does not have unique CheckCastPP";)
629 can_eliminate = false;
630 } else {
631 res_type = igvn->type(res)->isa_oopptr();
632 if (res_type == nullptr) {
633 NOT_PRODUCT(fail_eliminate = "Neither instance or array allocation";)
634 can_eliminate = false;
635 } else if (!res_type->klass_is_exact()) {
636 NOT_PRODUCT(fail_eliminate = "Not an exact type.";)
637 can_eliminate = false;
638 } else if (res_type->isa_aryptr()) {
639 int length = alloc->in(AllocateNode::ALength)->find_int_con(-1);
640 if (length < 0) {
641 NOT_PRODUCT(fail_eliminate = "Array's size is not constant";)
642 can_eliminate = false;
643 }
644 }
645 }
646
647 if (can_eliminate && res != nullptr) {
648 BarrierSetC2 *bs = BarrierSet::barrier_set()->barrier_set_c2();
649 for (DUIterator_Fast jmax, j = res->fast_outs(jmax);
650 j < jmax && can_eliminate; j++) {
651 Node* use = res->fast_out(j);
652
653 if (use->is_AddP()) {
654 const TypePtr* addp_type = igvn->type(use)->is_ptr();
655 int offset = addp_type->offset();
656
657 if (offset == Type::OffsetTop || offset == Type::OffsetBot) {
658 NOT_PRODUCT(fail_eliminate = "Undefined field reference";)
659 can_eliminate = false;
660 break;
661 }
662 for (DUIterator_Fast kmax, k = use->fast_outs(kmax);
663 k < kmax && can_eliminate; k++) {
664 Node* n = use->fast_out(k);
665 if (n->is_Mem() && n->as_Mem()->is_mismatched_access()) {
666 DEBUG_ONLY(disq_node = n);
667 NOT_PRODUCT(fail_eliminate = "Mismatched access");
668 can_eliminate = false;
669 }
670 if (!n->is_Store() && n->Opcode() != Op_CastP2X && !bs->is_gc_pre_barrier_node(n) && !reduce_merge_precheck) {
671 DEBUG_ONLY(disq_node = n;)
672 if (n->is_Load() || n->is_LoadStore()) {
673 NOT_PRODUCT(fail_eliminate = "Field load";)
674 } else {
675 NOT_PRODUCT(fail_eliminate = "Not store field reference";)
676 }
677 can_eliminate = false;
678 }
679 }
680 } else if (use->is_ArrayCopy() &&
681 (use->as_ArrayCopy()->is_clonebasic() ||
682 use->as_ArrayCopy()->is_arraycopy_validated() ||
683 use->as_ArrayCopy()->is_copyof_validated() ||
684 use->as_ArrayCopy()->is_copyofrange_validated()) &&
685 use->in(ArrayCopyNode::Dest) == res) {
686 // ok to eliminate
687 } else if (use->is_ReachabilityFence() && OptimizeReachabilityFences) {
688 // ok to eliminate
689 } else if (use->is_SafePoint()) {
690 SafePointNode* sfpt = use->as_SafePoint();
691 if (sfpt->is_Call() && sfpt->as_Call()->has_non_debug_use(res)) {
692 // Object is passed as argument.
693 DEBUG_ONLY(disq_node = use;)
694 NOT_PRODUCT(fail_eliminate = "Object is passed as argument";)
695 can_eliminate = false;
696 }
697 Node* sfptMem = sfpt->memory();
698 if (sfptMem == nullptr || sfptMem->is_top()) {
699 DEBUG_ONLY(disq_node = use;)
700 NOT_PRODUCT(fail_eliminate = "null or TOP memory";)
701 can_eliminate = false;
702 } else if (!reduce_merge_precheck) {
703 safepoints->append_if_missing(sfpt);
704 }
705 } else if (reduce_merge_precheck &&
706 (use->is_Phi() || use->is_EncodeP() ||
707 use->Opcode() == Op_MemBarRelease ||
708 (UseStoreStoreForCtor && use->Opcode() == Op_MemBarStoreStore))) {
709 // Nothing to do
710 } else if (use->Opcode() != Op_CastP2X) { // CastP2X is used by card mark
711 if (use->is_Phi()) {
712 if (use->outcnt() == 1 && use->unique_out()->Opcode() == Op_Return) {
713 NOT_PRODUCT(fail_eliminate = "Object is return value";)
714 } else {
715 NOT_PRODUCT(fail_eliminate = "Object is referenced by Phi";)
716 }
717 DEBUG_ONLY(disq_node = use;)
718 } else {
719 if (use->Opcode() == Op_Return) {
720 NOT_PRODUCT(fail_eliminate = "Object is return value";)
721 } else {
722 NOT_PRODUCT(fail_eliminate = "Object is referenced by node";)
723 }
724 DEBUG_ONLY(disq_node = use;)
725 }
726 can_eliminate = false;
727 }
728 }
729 }
730
731 #ifndef PRODUCT
732 if (PrintEliminateAllocations && safepoints != nullptr) {
733 if (can_eliminate) {
734 tty->print("Scalar ");
735 if (res == nullptr)
736 alloc->dump();
737 else
738 res->dump();
739 } else if (alloc->_is_scalar_replaceable) {
740 tty->print("NotScalar (%s)", fail_eliminate);
741 if (res == nullptr)
742 alloc->dump();
743 else
744 res->dump();
745 #ifdef ASSERT
746 if (disq_node != nullptr) {
747 tty->print(" >>>> ");
748 disq_node->dump();
749 }
750 #endif /*ASSERT*/
751 }
752 }
753
754 if (TraceReduceAllocationMerges && !can_eliminate && reduce_merge_precheck) {
755 tty->print_cr("\tCan't eliminate allocation because '%s': ", fail_eliminate != nullptr ? fail_eliminate : "");
756 DEBUG_ONLY(if (disq_node != nullptr) disq_node->dump();)
757 }
758 #endif
759 return can_eliminate;
760 }
761
762 void PhaseMacroExpand::undo_previous_scalarizations(GrowableArray <SafePointNode *> safepoints_done, AllocateNode* alloc) {
763 Node* res = alloc->result_cast();
764 int nfields = 0;
765 assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
766
767 if (res != nullptr) {
768 const TypeOopPtr* res_type = _igvn.type(res)->isa_oopptr();
769
770 if (res_type->isa_instptr()) {
771 // find the fields of the class which will be needed for safepoint debug information
772 ciInstanceKlass* iklass = res_type->is_instptr()->instance_klass();
773 nfields = iklass->nof_nonstatic_fields();
774 } else {
775 // find the array's elements which will be needed for safepoint debug information
776 nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
777 assert(nfields >= 0, "must be an array klass.");
778 }
779 }
780
781 // rollback processed safepoints
782 while (safepoints_done.length() > 0) {
783 SafePointNode* sfpt_done = safepoints_done.pop();
784
785 SafePointNode::NodeEdgeTempStorage non_debug_edges_worklist(igvn());
786
787 sfpt_done->remove_non_debug_edges(non_debug_edges_worklist);
788
789 // remove any extra entries we added to the safepoint
790 assert(sfpt_done->jvms()->endoff() == sfpt_done->req(), "no extra edges past debug info allowed");
791 uint last = sfpt_done->req() - 1;
792 for (int k = 0; k < nfields; k++) {
793 sfpt_done->del_req(last--);
794 }
795 JVMState *jvms = sfpt_done->jvms();
796 jvms->set_endoff(sfpt_done->req());
797 // Now make a pass over the debug information replacing any references
798 // to SafePointScalarObjectNode with the allocated object.
799 int start = jvms->debug_start();
800 int end = jvms->debug_end();
801 for (int i = start; i < end; i++) {
802 if (sfpt_done->in(i)->is_SafePointScalarObject()) {
803 SafePointScalarObjectNode* scobj = sfpt_done->in(i)->as_SafePointScalarObject();
804 if (scobj->first_index(jvms) == sfpt_done->req() &&
805 scobj->n_fields() == (uint)nfields) {
806 assert(scobj->alloc() == alloc, "sanity");
807 sfpt_done->set_req(i, res);
808 }
809 }
810 }
811
812 sfpt_done->restore_non_debug_edges(non_debug_edges_worklist);
813
814 _igvn._worklist.push(sfpt_done);
815 }
816 }
817
818 #ifdef ASSERT
819 // Verify if a value can be written into a field.
820 void verify_type_compatability(const Type* value_type, const Type* field_type) {
821 BasicType value_bt = value_type->basic_type();
822 BasicType field_bt = field_type->basic_type();
823
824 // Primitive types must match.
825 if (is_java_primitive(value_bt) && value_bt == field_bt) { return; }
826
827 // I have been struggling to make a similar assert for non-primitive
828 // types. I we can add one in the future. For now, I just let them
829 // pass without checks.
830 // In particular, I was struggling with a value that came from a call,
831 // and had only a non-null check CastPP. There was also a checkcast
832 // in the graph to verify the interface, but the corresponding
833 // CheckCastPP result was not updated in the stack slot, and so
834 // we ended up using the CastPP. That means that the field knows
835 // that it should get an oop from an interface, but the value lost
836 // that information, and so it is not a subtype.
837 // There may be other issues, feel free to investigate further!
838 if (!is_java_primitive(value_bt)) { return; }
839
840 tty->print_cr("value not compatible for field: %s vs %s",
841 type2name(value_bt),
842 type2name(field_bt));
843 tty->print("value_type: ");
844 value_type->dump();
845 tty->cr();
846 tty->print("field_type: ");
847 field_type->dump();
848 tty->cr();
849 assert(false, "value_type does not fit field_type");
850 }
851 #endif
852
853 SafePointScalarObjectNode* PhaseMacroExpand::create_scalarized_object_description(AllocateNode *alloc, SafePointNode* sfpt) {
854 assert(sfpt->jvms()->endoff() == sfpt->req(), "no extra edges past debug info allowed");
855
856 // Fields of scalar objs are referenced only at the end
857 // of regular debuginfo at the last (youngest) JVMS.
858 // Record relative start index.
859 ciInstanceKlass* iklass = nullptr;
860 BasicType basic_elem_type = T_ILLEGAL;
861 const Type* field_type = nullptr;
862 const TypeOopPtr* res_type = nullptr;
863 int nfields = 0;
864 int array_base = 0;
865 int element_size = 0;
866 uint first_ind = (sfpt->req() - sfpt->jvms()->scloff());
867 Node* res = alloc->result_cast();
868
869 assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
870 assert(sfpt->jvms() != nullptr, "missed JVMS");
871
872 if (res != nullptr) { // Could be null when there are no users
873 res_type = _igvn.type(res)->isa_oopptr();
874
875 if (res_type->isa_instptr()) {
876 // find the fields of the class which will be needed for safepoint debug information
877 iklass = res_type->is_instptr()->instance_klass();
878 nfields = iklass->nof_nonstatic_fields();
879 } else {
880 // find the array's elements which will be needed for safepoint debug information
881 nfields = alloc->in(AllocateNode::ALength)->find_int_con(-1);
882 assert(nfields >= 0, "must be an array klass.");
883 basic_elem_type = res_type->is_aryptr()->elem()->array_element_basic_type();
884 array_base = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
885 element_size = type2aelembytes(basic_elem_type);
886 field_type = res_type->is_aryptr()->elem();
887 }
888 }
889
890 SafePointScalarObjectNode* sobj = new SafePointScalarObjectNode(res_type, alloc, first_ind, sfpt->jvms()->depth(), nfields);
891 sobj->init_req(0, C->root());
892 transform_later(sobj);
893
894 // Scan object's fields adding an input to the safepoint for each field.
895 for (int j = 0; j < nfields; j++) {
896 intptr_t offset;
897 ciField* field = nullptr;
898 if (iklass != nullptr) {
899 field = iklass->nonstatic_field_at(j);
900 offset = field->offset_in_bytes();
901 ciType* elem_type = field->type();
902 basic_elem_type = field->layout_type();
903
904 // The next code is taken from Parse::do_get_xxx().
905 if (is_reference_type(basic_elem_type)) {
906 if (!elem_type->is_loaded()) {
907 field_type = TypeInstPtr::BOTTOM;
908 } else if (field != nullptr && field->is_static_constant()) {
909 ciObject* con = field->constant_value().as_object();
910 // Do not "join" in the previous type; it doesn't add value,
911 // and may yield a vacuous result if the field is of interface type.
912 field_type = TypeOopPtr::make_from_constant(con)->isa_oopptr();
913 assert(field_type != nullptr, "field singleton type must be consistent");
914 } else {
915 field_type = TypeOopPtr::make_from_klass(elem_type->as_klass());
916 }
917 if (UseCompressedOops) {
918 field_type = field_type->make_narrowoop();
919 basic_elem_type = T_NARROWOOP;
920 }
921 } else {
922 field_type = Type::get_const_basic_type(basic_elem_type);
923 }
924 } else {
925 offset = array_base + j * (intptr_t)element_size;
926 }
927
928 const TypeOopPtr *field_addr_type = res_type->add_offset(offset)->isa_oopptr();
929
930 Node* field_val = value_from_mem(sfpt, sfpt->control(), basic_elem_type, field_type, field_addr_type, alloc);
931
932 // We weren't able to find a value for this field,
933 // give up on eliminating this allocation.
934 if (field_val == nullptr) {
935 uint last = sfpt->req() - 1;
936 for (int k = 0; k < j; k++) {
937 sfpt->del_req(last--);
938 }
939 _igvn._worklist.push(sfpt);
940
941 #ifndef PRODUCT
942 if (PrintEliminateAllocations) {
943 if (field != nullptr) {
944 tty->print("=== At SafePoint node %d can't find value of field: ", sfpt->_idx);
945 field->print();
946 int field_idx = C->get_alias_index(field_addr_type);
947 tty->print(" (alias_idx=%d)", field_idx);
948 } else { // Array's element
949 tty->print("=== At SafePoint node %d can't find value of array element [%d]", sfpt->_idx, j);
950 }
951 tty->print(", which prevents elimination of: ");
952 if (res == nullptr)
953 alloc->dump();
954 else
955 res->dump();
956 }
957 #endif
958
959 return nullptr;
960 }
961
962 if (UseCompressedOops && field_type->isa_narrowoop()) {
963 // Enable "DecodeN(EncodeP(Allocate)) --> Allocate" transformation
964 // to be able scalar replace the allocation.
965 if (field_val->is_EncodeP()) {
966 field_val = field_val->in(1);
967 } else {
968 field_val = transform_later(new DecodeNNode(field_val, field_val->get_ptr_type()));
969 }
970 }
971 DEBUG_ONLY(verify_type_compatability(field_val->bottom_type(), field_type);)
972 sfpt->add_req(field_val);
973 }
974
975 sfpt->jvms()->set_endoff(sfpt->req());
976
977 return sobj;
978 }
979
980 // Do scalar replacement.
981 bool PhaseMacroExpand::scalar_replacement(AllocateNode* alloc, GrowableArray<SafePointNode*>& safepoints) {
982 GrowableArray<SafePointNode*> safepoints_done;
983 Node* res = alloc->result_cast();
984 assert(res == nullptr || res->is_CheckCastPP(), "unexpected AllocateNode result");
985
986 // Process the safepoint uses
987 while (safepoints.length() > 0) {
988 SafePointNode* sfpt = safepoints.pop();
989
990 SafePointNode::NodeEdgeTempStorage non_debug_edges_worklist(igvn());
991
992 // All sfpt inputs are implicitly included into debug info during the scalarization process below.
993 // Keep non-debug inputs separately, so they stay non-debug.
994 sfpt->remove_non_debug_edges(non_debug_edges_worklist);
995
996 SafePointScalarObjectNode* sobj = create_scalarized_object_description(alloc, sfpt);
997
998 if (sobj == nullptr) {
999 sfpt->restore_non_debug_edges(non_debug_edges_worklist);
1000 undo_previous_scalarizations(safepoints_done, alloc);
1001 return false;
1002 }
1003
1004 // Now make a pass over the debug information replacing any references
1005 // to the allocated object with "sobj"
1006 JVMState *jvms = sfpt->jvms();
1007 sfpt->replace_edges_in_range(res, sobj, jvms->debug_start(), jvms->debug_end(), &_igvn);
1008 non_debug_edges_worklist.remove_edge_if_present(res); // drop scalarized input from non-debug info
1009 sfpt->restore_non_debug_edges(non_debug_edges_worklist);
1010 _igvn._worklist.push(sfpt);
1011
1012 // keep it for rollback
1013 safepoints_done.append_if_missing(sfpt);
1014 }
1015
1016 return true;
1017 }
1018
1019 static void disconnect_projections(MultiNode* n, PhaseIterGVN& igvn) {
1020 Node* ctl_proj = n->proj_out_or_null(TypeFunc::Control);
1021 Node* mem_proj = n->proj_out_or_null(TypeFunc::Memory);
1022 if (ctl_proj != nullptr) {
1023 igvn.replace_node(ctl_proj, n->in(0));
1024 }
1025 if (mem_proj != nullptr) {
1026 igvn.replace_node(mem_proj, n->in(TypeFunc::Memory));
1027 }
1028 }
1029
1030 // Process users of eliminated allocation.
1031 void PhaseMacroExpand::process_users_of_allocation(CallNode *alloc) {
1032 Node* res = alloc->result_cast();
1033 if (res != nullptr) {
1034 for (DUIterator_Last jmin, j = res->last_outs(jmin); j >= jmin; ) {
1035 Node *use = res->last_out(j);
1036 uint oc1 = res->outcnt();
1037
1038 if (use->is_AddP()) {
1039 for (DUIterator_Last kmin, k = use->last_outs(kmin); k >= kmin; ) {
1040 Node *n = use->last_out(k);
1041 uint oc2 = use->outcnt();
1042 if (n->is_Store()) {
1043 #ifdef ASSERT
1044 // Verify that there is no dependent MemBarVolatile nodes,
1045 // they should be removed during IGVN, see MemBarNode::Ideal().
1046 for (DUIterator_Fast pmax, p = n->fast_outs(pmax);
1047 p < pmax; p++) {
1048 Node* mb = n->fast_out(p);
1049 assert(mb->is_Initialize() || !mb->is_MemBar() ||
1050 mb->req() <= MemBarNode::Precedent ||
1051 mb->in(MemBarNode::Precedent) != n,
1052 "MemBarVolatile should be eliminated for non-escaping object");
1053 }
1054 #endif
1055 _igvn.replace_node(n, n->in(MemNode::Memory));
1056 } else {
1057 eliminate_gc_barrier(n);
1058 }
1059 k -= (oc2 - use->outcnt());
1060 }
1061 _igvn.remove_dead_node(use, PhaseIterGVN::NodeOrigin::Graph);
1062 } else if (use->is_ArrayCopy()) {
1063 // Disconnect ArrayCopy node
1064 ArrayCopyNode* ac = use->as_ArrayCopy();
1065 if (ac->is_clonebasic()) {
1066 Node* membar_after = ac->proj_out(TypeFunc::Control)->unique_ctrl_out();
1067 disconnect_projections(ac, _igvn);
1068 assert(alloc->in(TypeFunc::Memory)->is_Proj() && alloc->in(TypeFunc::Memory)->in(0)->Opcode() == Op_MemBarCPUOrder, "mem barrier expected before allocation");
1069 Node* membar_before = alloc->in(TypeFunc::Memory)->in(0);
1070 disconnect_projections(membar_before->as_MemBar(), _igvn);
1071 if (membar_after->is_MemBar()) {
1072 disconnect_projections(membar_after->as_MemBar(), _igvn);
1073 }
1074 } else {
1075 assert(ac->is_arraycopy_validated() ||
1076 ac->is_copyof_validated() ||
1077 ac->is_copyofrange_validated(), "unsupported");
1078 CallProjections callprojs;
1079 ac->extract_projections(&callprojs, true);
1080
1081 _igvn.replace_node(callprojs.fallthrough_ioproj, ac->in(TypeFunc::I_O));
1082 _igvn.replace_node(callprojs.fallthrough_memproj, ac->in(TypeFunc::Memory));
1083 _igvn.replace_node(callprojs.fallthrough_catchproj, ac->in(TypeFunc::Control));
1084
1085 // Set control to top. IGVN will remove the remaining projections
1086 ac->set_req(0, top());
1087 ac->replace_edge(res, top(), &_igvn);
1088
1089 // Disconnect src right away: it can help find new
1090 // opportunities for allocation elimination
1091 Node* src = ac->in(ArrayCopyNode::Src);
1092 ac->replace_edge(src, top(), &_igvn);
1093 // src can be top at this point if src and dest of the
1094 // arraycopy were the same
1095 if (src->outcnt() == 0 && !src->is_top()) {
1096 _igvn.remove_dead_node(src, PhaseIterGVN::NodeOrigin::Graph);
1097 }
1098 }
1099 _igvn._worklist.push(ac);
1100 } else if (use->is_ReachabilityFence() && OptimizeReachabilityFences) {
1101 use->as_ReachabilityFence()->clear_referent(_igvn); // redundant fence; will be removed during IGVN
1102 } else {
1103 eliminate_gc_barrier(use);
1104 }
1105 j -= (oc1 - res->outcnt());
1106 }
1107 assert(res->outcnt() == 0, "all uses of allocated objects must be deleted");
1108 _igvn.remove_dead_node(res, PhaseIterGVN::NodeOrigin::Graph);
1109 }
1110
1111 //
1112 // Process other users of allocation's projections
1113 //
1114 if (_callprojs.resproj != nullptr && _callprojs.resproj->outcnt() != 0) {
1115 // First disconnect stores captured by Initialize node.
1116 // If Initialize node is eliminated first in the following code,
1117 // it will kill such stores and DUIterator_Last will assert.
1118 for (DUIterator_Fast jmax, j = _callprojs.resproj->fast_outs(jmax); j < jmax; j++) {
1119 Node* use = _callprojs.resproj->fast_out(j);
1120 if (use->is_AddP()) {
1121 // raw memory addresses used only by the initialization
1122 _igvn.replace_node(use, C->top());
1123 --j; --jmax;
1124 }
1125 }
1126 for (DUIterator_Last jmin, j = _callprojs.resproj->last_outs(jmin); j >= jmin; ) {
1127 Node* use = _callprojs.resproj->last_out(j);
1128 uint oc1 = _callprojs.resproj->outcnt();
1129 if (use->is_Initialize()) {
1130 // Eliminate Initialize node.
1131 InitializeNode *init = use->as_Initialize();
1132 Node *ctrl_proj = init->proj_out_or_null(TypeFunc::Control);
1133 if (ctrl_proj != nullptr) {
1134 _igvn.replace_node(ctrl_proj, init->in(TypeFunc::Control));
1135 #ifdef ASSERT
1136 // If the InitializeNode has no memory out, it will die, and tmp will become null
1137 Node* tmp = init->in(TypeFunc::Control);
1138 assert(tmp == nullptr || tmp == _callprojs.fallthrough_catchproj, "allocation control projection");
1139 #endif
1140 }
1141 Node* mem = init->in(TypeFunc::Memory);
1142 #ifdef ASSERT
1143 if (init->number_of_projs(TypeFunc::Memory) > 0) {
1144 if (mem->is_MergeMem()) {
1145 assert(mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw) == _callprojs.fallthrough_memproj, "allocation memory projection");
1146 } else {
1147 assert(mem == _callprojs.fallthrough_memproj, "allocation memory projection");
1148 }
1149 }
1150 #endif
1151 init->replace_mem_projs_by(mem, &_igvn);
1152 assert(init->outcnt() == 0, "should only have had a control and some memory projections, and we removed them");
1153 } else {
1154 assert(false, "only Initialize or AddP expected");
1155 }
1156 j -= (oc1 - _callprojs.resproj->outcnt());
1157 }
1158 }
1159 if (_callprojs.fallthrough_catchproj != nullptr) {
1160 _igvn.replace_node(_callprojs.fallthrough_catchproj, alloc->in(TypeFunc::Control));
1161 }
1162 if (_callprojs.fallthrough_memproj != nullptr) {
1163 _igvn.replace_node(_callprojs.fallthrough_memproj, alloc->in(TypeFunc::Memory));
1164 }
1165 if (_callprojs.catchall_memproj != nullptr) {
1166 _igvn.replace_node(_callprojs.catchall_memproj, C->top());
1167 }
1168 if (_callprojs.fallthrough_ioproj != nullptr) {
1169 _igvn.replace_node(_callprojs.fallthrough_ioproj, alloc->in(TypeFunc::I_O));
1170 }
1171 if (_callprojs.catchall_ioproj != nullptr) {
1172 _igvn.replace_node(_callprojs.catchall_ioproj, C->top());
1173 }
1174 if (_callprojs.catchall_catchproj != nullptr) {
1175 _igvn.replace_node(_callprojs.catchall_catchproj, C->top());
1176 }
1177 }
1178
1179 bool PhaseMacroExpand::eliminate_allocate_node(AllocateNode *alloc) {
1180 // If reallocation fails during deoptimization we'll pop all
1181 // interpreter frames for this compiled frame and that won't play
1182 // nice with JVMTI popframe.
1183 // We avoid this issue by eager reallocation when the popframe request
1184 // is received.
1185 if (!EliminateAllocations || !alloc->_is_non_escaping) {
1186 return false;
1187 }
1188 Node* klass = alloc->in(AllocateNode::KlassNode);
1189 const TypeKlassPtr* tklass = _igvn.type(klass)->is_klassptr();
1190 Node* res = alloc->result_cast();
1191 // Eliminate boxing allocations which are not used
1192 // regardless scalar replaceable status.
1193 bool boxing_alloc = C->eliminate_boxing() &&
1194 tklass->isa_instklassptr() &&
1195 tklass->is_instklassptr()->instance_klass()->is_box_klass();
1196 if (!alloc->_is_scalar_replaceable && (!boxing_alloc || (res != nullptr))) {
1197 return false;
1198 }
1199
1200 alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1201
1202 GrowableArray <SafePointNode *> safepoints;
1203 if (!can_eliminate_allocation(&_igvn, alloc, &safepoints)) {
1204 return false;
1205 }
1206
1207 if (!alloc->_is_scalar_replaceable) {
1208 assert(res == nullptr, "sanity");
1209 // We can only eliminate allocation if all debug info references
1210 // are already replaced with SafePointScalarObject because
1211 // we can't search for a fields value without instance_id.
1212 if (safepoints.length() > 0) {
1213 return false;
1214 }
1215 }
1216
1217 if (!scalar_replacement(alloc, safepoints)) {
1218 return false;
1219 }
1220
1221 CompileLog* log = C->log();
1222 if (log != nullptr) {
1223 log->head("eliminate_allocation type='%d'",
1224 log->identify(tklass->exact_klass()));
1225 JVMState* p = alloc->jvms();
1226 while (p != nullptr) {
1227 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1228 p = p->caller();
1229 }
1230 log->tail("eliminate_allocation");
1231 }
1232
1233 process_users_of_allocation(alloc);
1234
1235 #ifndef PRODUCT
1236 if (PrintEliminateAllocations) {
1237 if (alloc->is_AllocateArray())
1238 tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1239 else
1240 tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1241 }
1242 #endif
1243
1244 return true;
1245 }
1246
1247 bool PhaseMacroExpand::eliminate_boxing_node(CallStaticJavaNode *boxing) {
1248 // EA should remove all uses of non-escaping boxing node.
1249 if (!C->eliminate_boxing() || boxing->proj_out_or_null(TypeFunc::Parms) != nullptr) {
1250 return false;
1251 }
1252
1253 assert(boxing->result_cast() == nullptr, "unexpected boxing node result");
1254
1255 boxing->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1256
1257 const TypeTuple* r = boxing->tf()->range();
1258 assert(r->cnt() > TypeFunc::Parms, "sanity");
1259 const TypeInstPtr* t = r->field_at(TypeFunc::Parms)->isa_instptr();
1260 assert(t != nullptr, "sanity");
1261
1262 CompileLog* log = C->log();
1263 if (log != nullptr) {
1264 log->head("eliminate_boxing type='%d'",
1265 log->identify(t->instance_klass()));
1266 JVMState* p = boxing->jvms();
1267 while (p != nullptr) {
1268 log->elem("jvms bci='%d' method='%d'", p->bci(), log->identify(p->method()));
1269 p = p->caller();
1270 }
1271 log->tail("eliminate_boxing");
1272 }
1273
1274 process_users_of_allocation(boxing);
1275
1276 #ifndef PRODUCT
1277 if (PrintEliminateAllocations) {
1278 tty->print("++++ Eliminated: %d ", boxing->_idx);
1279 boxing->method()->print_short_name(tty);
1280 tty->cr();
1281 }
1282 #endif
1283
1284 return true;
1285 }
1286
1287
1288 Node* PhaseMacroExpand::make_load_raw(Node* ctl, Node* mem, Node* base, int offset, const Type* value_type, BasicType bt) {
1289 Node* adr = off_heap_plus_addr(base, offset);
1290 const TypePtr* adr_type = adr->bottom_type()->is_ptr();
1291 Node* value = LoadNode::make(_igvn, ctl, mem, adr, adr_type, value_type, bt, MemNode::unordered);
1292 transform_later(value);
1293 return value;
1294 }
1295
1296
1297 Node* PhaseMacroExpand::make_store_raw(Node* ctl, Node* mem, Node* base, int offset, Node* value, BasicType bt) {
1298 Node* adr = off_heap_plus_addr(base, offset);
1299 mem = StoreNode::make(_igvn, ctl, mem, adr, nullptr, value, bt, MemNode::unordered);
1300 transform_later(mem);
1301 return mem;
1302 }
1303
1304 //=============================================================================
1305 //
1306 // A L L O C A T I O N
1307 //
1308 // Allocation attempts to be fast in the case of frequent small objects.
1309 // It breaks down like this:
1310 //
1311 // 1) Size in doublewords is computed. This is a constant for objects and
1312 // variable for most arrays. Doubleword units are used to avoid size
1313 // overflow of huge doubleword arrays. We need doublewords in the end for
1314 // rounding.
1315 //
1316 // 2) Size is checked for being 'too large'. Too-large allocations will go
1317 // the slow path into the VM. The slow path can throw any required
1318 // exceptions, and does all the special checks for very large arrays. The
1319 // size test can constant-fold away for objects. For objects with
1320 // finalizers it constant-folds the otherway: you always go slow with
1321 // finalizers.
1322 //
1323 // 3) If NOT using TLABs, this is the contended loop-back point.
1324 // Load-Locked the heap top. If using TLABs normal-load the heap top.
1325 //
1326 // 4) Check that heap top + size*8 < max. If we fail go the slow ` route.
1327 // NOTE: "top+size*8" cannot wrap the 4Gig line! Here's why: for largish
1328 // "size*8" we always enter the VM, where "largish" is a constant picked small
1329 // enough that there's always space between the eden max and 4Gig (old space is
1330 // there so it's quite large) and large enough that the cost of entering the VM
1331 // is dwarfed by the cost to initialize the space.
1332 //
1333 // 5) If NOT using TLABs, Store-Conditional the adjusted heap top back
1334 // down. If contended, repeat at step 3. If using TLABs normal-store
1335 // adjusted heap top back down; there is no contention.
1336 //
1337 // 6) If !ZeroTLAB then Bulk-clear the object/array. Fill in klass & mark
1338 // fields.
1339 //
1340 // 7) Merge with the slow-path; cast the raw memory pointer to the correct
1341 // oop flavor.
1342 //
1343 //=============================================================================
1344 // FastAllocateSizeLimit value is in DOUBLEWORDS.
1345 // Allocations bigger than this always go the slow route.
1346 // This value must be small enough that allocation attempts that need to
1347 // trigger exceptions go the slow route. Also, it must be small enough so
1348 // that heap_top + size_in_bytes does not wrap around the 4Gig limit.
1349 //=============================================================================j//
1350 // %%% Here is an old comment from parseHelper.cpp; is it outdated?
1351 // The allocator will coalesce int->oop copies away. See comment in
1352 // coalesce.cpp about how this works. It depends critically on the exact
1353 // code shape produced here, so if you are changing this code shape
1354 // make sure the GC info for the heap-top is correct in and around the
1355 // slow-path call.
1356 //
1357
1358 void PhaseMacroExpand::expand_allocate_common(
1359 AllocateNode* alloc, // allocation node to be expanded
1360 Node* length, // array length for an array allocation
1361 const TypeFunc* slow_call_type, // Type of slow call
1362 address slow_call_address, // Address of slow call
1363 Node* valid_length_test // whether length is valid or not
1364 )
1365 {
1366 Node* ctrl = alloc->in(TypeFunc::Control);
1367 Node* mem = alloc->in(TypeFunc::Memory);
1368 Node* i_o = alloc->in(TypeFunc::I_O);
1369 Node* size_in_bytes = alloc->in(AllocateNode::AllocSize);
1370 Node* klass_node = alloc->in(AllocateNode::KlassNode);
1371 Node* initial_slow_test = alloc->in(AllocateNode::InitialTest);
1372 assert(ctrl != nullptr, "must have control");
1373
1374 // We need a Region and corresponding Phi's to merge the slow-path and fast-path results.
1375 // they will not be used if "always_slow" is set
1376 enum { slow_result_path = 1, fast_result_path = 2 };
1377 Node *result_region = nullptr;
1378 Node *result_phi_rawmem = nullptr;
1379 Node *result_phi_rawoop = nullptr;
1380 Node *result_phi_i_o = nullptr;
1381
1382 // The initial slow comparison is a size check, the comparison
1383 // we want to do is a BoolTest::gt
1384 bool expand_fast_path = true;
1385 int tv = _igvn.find_int_con(initial_slow_test, -1);
1386 if (tv >= 0) {
1387 // InitialTest has constant result
1388 // 0 - can fit in TLAB
1389 // 1 - always too big or negative
1390 assert(tv <= 1, "0 or 1 if a constant");
1391 expand_fast_path = (tv == 0);
1392 initial_slow_test = nullptr;
1393 } else {
1394 initial_slow_test = BoolNode::make_predicate(initial_slow_test, &_igvn);
1395 }
1396
1397 if (!UseTLAB) {
1398 // Force slow-path allocation
1399 expand_fast_path = false;
1400 initial_slow_test = nullptr;
1401 }
1402
1403 // ArrayCopyNode right after an allocation operates on the raw result projection for the Allocate node so it's not
1404 // safe to remove such an allocation even if it has no result cast.
1405 bool allocation_has_use = (alloc->result_cast() != nullptr) || (alloc->initialization() != nullptr && alloc->initialization()->is_complete_with_arraycopy());
1406 if (!allocation_has_use) {
1407 InitializeNode* init = alloc->initialization();
1408 if (init != nullptr) {
1409 init->remove(&_igvn);
1410 }
1411 if (expand_fast_path && (initial_slow_test == nullptr)) {
1412 // Remove allocation node and return.
1413 // Size is a non-negative constant -> no initial check needed -> directly to fast path.
1414 // Also, no usages -> empty fast path -> no fall out to slow path -> nothing left.
1415 #ifndef PRODUCT
1416 if (PrintEliminateAllocations) {
1417 tty->print("NotUsed ");
1418 Node* res = alloc->proj_out_or_null(TypeFunc::Parms);
1419 if (res != nullptr) {
1420 res->dump();
1421 } else {
1422 alloc->dump();
1423 }
1424 }
1425 #endif
1426 yank_alloc_node(alloc);
1427 return;
1428 }
1429 }
1430
1431 enum { too_big_or_final_path = 1, need_gc_path = 2 };
1432 Node *slow_region = nullptr;
1433 Node *toobig_false = ctrl;
1434
1435 // generate the initial test if necessary
1436 if (initial_slow_test != nullptr ) {
1437 assert (expand_fast_path, "Only need test if there is a fast path");
1438 slow_region = new RegionNode(3);
1439
1440 // Now make the initial failure test. Usually a too-big test but
1441 // might be a TRUE for finalizers.
1442 IfNode *toobig_iff = new IfNode(ctrl, initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
1443 transform_later(toobig_iff);
1444 // Plug the failing-too-big test into the slow-path region
1445 Node *toobig_true = new IfTrueNode( toobig_iff );
1446 transform_later(toobig_true);
1447 slow_region ->init_req( too_big_or_final_path, toobig_true );
1448 toobig_false = new IfFalseNode( toobig_iff );
1449 transform_later(toobig_false);
1450 } else {
1451 // No initial test, just fall into next case
1452 assert(allocation_has_use || !expand_fast_path, "Should already have been handled");
1453 toobig_false = ctrl;
1454 DEBUG_ONLY(slow_region = NodeSentinel);
1455 }
1456
1457 // If we are here there are several possibilities
1458 // - expand_fast_path is false - then only a slow path is expanded. That's it.
1459 // no_initial_check means a constant allocation.
1460 // - If check always evaluates to false -> expand_fast_path is false (see above)
1461 // - If check always evaluates to true -> directly into fast path (but may bailout to slowpath)
1462 // if !allocation_has_use the fast path is empty
1463 // if !allocation_has_use && no_initial_check
1464 // - Then there are no fastpath that can fall out to slowpath -> no allocation code at all.
1465 // removed by yank_alloc_node above.
1466
1467 Node *slow_mem = mem; // save the current memory state for slow path
1468 // generate the fast allocation code unless we know that the initial test will always go slow
1469 if (expand_fast_path) {
1470 // Fast path modifies only raw memory.
1471 if (mem->is_MergeMem()) {
1472 mem = mem->as_MergeMem()->memory_at(Compile::AliasIdxRaw);
1473 }
1474
1475 // allocate the Region and Phi nodes for the result
1476 result_region = new RegionNode(3);
1477 result_phi_rawmem = new PhiNode(result_region, Type::MEMORY, TypeRawPtr::BOTTOM);
1478 result_phi_i_o = new PhiNode(result_region, Type::ABIO); // I/O is used for Prefetch
1479
1480 // Grab regular I/O before optional prefetch may change it.
1481 // Slow-path does no I/O so just set it to the original I/O.
1482 result_phi_i_o->init_req(slow_result_path, i_o);
1483
1484 // Name successful fast-path variables
1485 Node* fast_oop_ctrl;
1486 Node* fast_oop_rawmem;
1487 if (allocation_has_use) {
1488 Node* needgc_ctrl = nullptr;
1489 result_phi_rawoop = new PhiNode(result_region, TypeRawPtr::BOTTOM);
1490
1491 intx prefetch_lines = length != nullptr ? AllocatePrefetchLines : AllocateInstancePrefetchLines;
1492 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1493 Node* fast_oop = bs->obj_allocate(this, mem, toobig_false, size_in_bytes, i_o, needgc_ctrl,
1494 fast_oop_ctrl, fast_oop_rawmem,
1495 prefetch_lines);
1496
1497 if (initial_slow_test != nullptr) {
1498 // This completes all paths into the slow merge point
1499 slow_region->init_req(need_gc_path, needgc_ctrl);
1500 transform_later(slow_region);
1501 } else {
1502 // No initial slow path needed!
1503 // Just fall from the need-GC path straight into the VM call.
1504 slow_region = needgc_ctrl;
1505 }
1506
1507 InitializeNode* init = alloc->initialization();
1508 fast_oop_rawmem = initialize_object(alloc,
1509 fast_oop_ctrl, fast_oop_rawmem, fast_oop,
1510 klass_node, length, size_in_bytes);
1511 expand_initialize_membar(alloc, init, fast_oop_ctrl, fast_oop_rawmem);
1512 expand_dtrace_alloc_probe(alloc, fast_oop, fast_oop_ctrl, fast_oop_rawmem);
1513
1514 result_phi_rawoop->init_req(fast_result_path, fast_oop);
1515 } else {
1516 assert (initial_slow_test != nullptr, "sanity");
1517 fast_oop_ctrl = toobig_false;
1518 fast_oop_rawmem = mem;
1519 transform_later(slow_region);
1520 }
1521
1522 // Plug in the successful fast-path into the result merge point
1523 result_region ->init_req(fast_result_path, fast_oop_ctrl);
1524 result_phi_i_o ->init_req(fast_result_path, i_o);
1525 result_phi_rawmem->init_req(fast_result_path, fast_oop_rawmem);
1526 } else {
1527 slow_region = ctrl;
1528 result_phi_i_o = i_o; // Rename it to use in the following code.
1529 }
1530
1531 // Generate slow-path call
1532 CallNode *call = new CallStaticJavaNode(slow_call_type, slow_call_address,
1533 OptoRuntime::stub_name(slow_call_address),
1534 TypePtr::BOTTOM);
1535 call->init_req(TypeFunc::Control, slow_region);
1536 call->init_req(TypeFunc::I_O, top()); // does no i/o
1537 call->init_req(TypeFunc::Memory, slow_mem); // may gc ptrs
1538 call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1539 call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
1540
1541 call->init_req(TypeFunc::Parms+0, klass_node);
1542 if (length != nullptr) {
1543 call->init_req(TypeFunc::Parms+1, length);
1544 }
1545
1546 // Copy debug information and adjust JVMState information, then replace
1547 // allocate node with the call
1548 call->copy_call_debug_info(&_igvn, alloc);
1549 // For array allocations, copy the valid length check to the call node so Compile::final_graph_reshaping() can verify
1550 // that the call has the expected number of CatchProj nodes (in case the allocation always fails and the fallthrough
1551 // path dies).
1552 if (valid_length_test != nullptr) {
1553 call->add_req(valid_length_test);
1554 }
1555 if (expand_fast_path) {
1556 call->set_cnt(PROB_UNLIKELY_MAG(4)); // Same effect as RC_UNCOMMON.
1557 } else {
1558 // Hook i_o projection to avoid its elimination during allocation
1559 // replacement (when only a slow call is generated).
1560 call->set_req(TypeFunc::I_O, result_phi_i_o);
1561 }
1562 _igvn.replace_node(alloc, call);
1563 transform_later(call);
1564
1565 // Identify the output projections from the allocate node and
1566 // adjust any references to them.
1567 // The control and io projections look like:
1568 //
1569 // v---Proj(ctrl) <-----+ v---CatchProj(ctrl)
1570 // Allocate Catch
1571 // ^---Proj(io) <-------+ ^---CatchProj(io)
1572 //
1573 // We are interested in the CatchProj nodes.
1574 //
1575 call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1576
1577 // An allocate node has separate memory projections for the uses on
1578 // the control and i_o paths. Replace the control memory projection with
1579 // result_phi_rawmem (unless we are only generating a slow call when
1580 // both memory projections are combined)
1581 if (expand_fast_path && _callprojs.fallthrough_memproj != nullptr) {
1582 migrate_outs(_callprojs.fallthrough_memproj, result_phi_rawmem);
1583 }
1584 // Now change uses of catchall_memproj to use fallthrough_memproj and delete
1585 // catchall_memproj so we end up with a call that has only 1 memory projection.
1586 if (_callprojs.catchall_memproj != nullptr ) {
1587 if (_callprojs.fallthrough_memproj == nullptr) {
1588 _callprojs.fallthrough_memproj = new ProjNode(call, TypeFunc::Memory);
1589 transform_later(_callprojs.fallthrough_memproj);
1590 }
1591 migrate_outs(_callprojs.catchall_memproj, _callprojs.fallthrough_memproj);
1592 _igvn.remove_dead_node(_callprojs.catchall_memproj, PhaseIterGVN::NodeOrigin::Graph);
1593 }
1594
1595 // An allocate node has separate i_o projections for the uses on the control
1596 // and i_o paths. Always replace the control i_o projection with result i_o
1597 // otherwise incoming i_o become dead when only a slow call is generated
1598 // (it is different from memory projections where both projections are
1599 // combined in such case).
1600 if (_callprojs.fallthrough_ioproj != nullptr) {
1601 migrate_outs(_callprojs.fallthrough_ioproj, result_phi_i_o);
1602 }
1603 // Now change uses of catchall_ioproj to use fallthrough_ioproj and delete
1604 // catchall_ioproj so we end up with a call that has only 1 i_o projection.
1605 if (_callprojs.catchall_ioproj != nullptr ) {
1606 if (_callprojs.fallthrough_ioproj == nullptr) {
1607 _callprojs.fallthrough_ioproj = new ProjNode(call, TypeFunc::I_O);
1608 transform_later(_callprojs.fallthrough_ioproj);
1609 }
1610 migrate_outs(_callprojs.catchall_ioproj, _callprojs.fallthrough_ioproj);
1611 _igvn.remove_dead_node(_callprojs.catchall_ioproj, PhaseIterGVN::NodeOrigin::Graph);
1612 }
1613
1614 // if we generated only a slow call, we are done
1615 if (!expand_fast_path) {
1616 // Now we can unhook i_o.
1617 if (result_phi_i_o->outcnt() > 1) {
1618 call->set_req(TypeFunc::I_O, top());
1619 } else {
1620 assert(result_phi_i_o->unique_ctrl_out() == call, "sanity");
1621 // Case of new array with negative size known during compilation.
1622 // AllocateArrayNode::Ideal() optimization disconnect unreachable
1623 // following code since call to runtime will throw exception.
1624 // As result there will be no users of i_o after the call.
1625 // Leave i_o attached to this call to avoid problems in preceding graph.
1626 }
1627 return;
1628 }
1629
1630 if (_callprojs.fallthrough_catchproj != nullptr) {
1631 ctrl = _callprojs.fallthrough_catchproj->clone();
1632 transform_later(ctrl);
1633 _igvn.replace_node(_callprojs.fallthrough_catchproj, result_region);
1634 } else {
1635 ctrl = top();
1636 }
1637 Node *slow_result;
1638 if (_callprojs.resproj == nullptr) {
1639 // no uses of the allocation result
1640 slow_result = top();
1641 } else {
1642 slow_result = _callprojs.resproj->clone();
1643 transform_later(slow_result);
1644 _igvn.replace_node(_callprojs.resproj, result_phi_rawoop);
1645 }
1646
1647 // Plug slow-path into result merge point
1648 result_region->init_req( slow_result_path, ctrl);
1649 transform_later(result_region);
1650 if (allocation_has_use) {
1651 result_phi_rawoop->init_req(slow_result_path, slow_result);
1652 transform_later(result_phi_rawoop);
1653 }
1654 result_phi_rawmem->init_req(slow_result_path, _callprojs.fallthrough_memproj);
1655 transform_later(result_phi_rawmem);
1656 transform_later(result_phi_i_o);
1657 // This completes all paths into the result merge point
1658 }
1659
1660 // Remove alloc node that has no uses.
1661 void PhaseMacroExpand::yank_alloc_node(AllocateNode* alloc) {
1662 Node* ctrl = alloc->in(TypeFunc::Control);
1663 Node* mem = alloc->in(TypeFunc::Memory);
1664 Node* i_o = alloc->in(TypeFunc::I_O);
1665
1666 alloc->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
1667 if (_callprojs.resproj != nullptr) {
1668 for (DUIterator_Fast imax, i = _callprojs.resproj->fast_outs(imax); i < imax; i++) {
1669 Node* use = _callprojs.resproj->fast_out(i);
1670 use->isa_MemBar()->remove(&_igvn);
1671 --imax;
1672 --i; // back up iterator
1673 }
1674 assert(_callprojs.resproj->outcnt() == 0, "all uses must be deleted");
1675 _igvn.remove_dead_node(_callprojs.resproj, PhaseIterGVN::NodeOrigin::Graph);
1676 }
1677 if (_callprojs.fallthrough_catchproj != nullptr) {
1678 migrate_outs(_callprojs.fallthrough_catchproj, ctrl);
1679 _igvn.remove_dead_node(_callprojs.fallthrough_catchproj, PhaseIterGVN::NodeOrigin::Graph);
1680 }
1681 if (_callprojs.catchall_catchproj != nullptr) {
1682 _igvn.rehash_node_delayed(_callprojs.catchall_catchproj);
1683 _callprojs.catchall_catchproj->set_req(0, top());
1684 }
1685 if (_callprojs.fallthrough_proj != nullptr) {
1686 Node* catchnode = _callprojs.fallthrough_proj->unique_ctrl_out();
1687 _igvn.remove_dead_node(catchnode, PhaseIterGVN::NodeOrigin::Graph);
1688 _igvn.remove_dead_node(_callprojs.fallthrough_proj, PhaseIterGVN::NodeOrigin::Graph);
1689 }
1690 if (_callprojs.fallthrough_memproj != nullptr) {
1691 migrate_outs(_callprojs.fallthrough_memproj, mem);
1692 _igvn.remove_dead_node(_callprojs.fallthrough_memproj, PhaseIterGVN::NodeOrigin::Graph);
1693 }
1694 if (_callprojs.fallthrough_ioproj != nullptr) {
1695 migrate_outs(_callprojs.fallthrough_ioproj, i_o);
1696 _igvn.remove_dead_node(_callprojs.fallthrough_ioproj, PhaseIterGVN::NodeOrigin::Graph);
1697 }
1698 if (_callprojs.catchall_memproj != nullptr) {
1699 _igvn.rehash_node_delayed(_callprojs.catchall_memproj);
1700 _callprojs.catchall_memproj->set_req(0, top());
1701 }
1702 if (_callprojs.catchall_ioproj != nullptr) {
1703 _igvn.rehash_node_delayed(_callprojs.catchall_ioproj);
1704 _callprojs.catchall_ioproj->set_req(0, top());
1705 }
1706 #ifndef PRODUCT
1707 if (PrintEliminateAllocations) {
1708 if (alloc->is_AllocateArray()) {
1709 tty->print_cr("++++ Eliminated: %d AllocateArray", alloc->_idx);
1710 } else {
1711 tty->print_cr("++++ Eliminated: %d Allocate", alloc->_idx);
1712 }
1713 }
1714 #endif
1715 _igvn.remove_dead_node(alloc, PhaseIterGVN::NodeOrigin::Graph);
1716 }
1717
1718 void PhaseMacroExpand::expand_initialize_membar(AllocateNode* alloc, InitializeNode* init,
1719 Node*& fast_oop_ctrl, Node*& fast_oop_rawmem) {
1720 // If initialization is performed by an array copy, any required
1721 // MemBarStoreStore was already added. If the object does not
1722 // escape no need for a MemBarStoreStore. If the object does not
1723 // escape in its initializer and memory barrier (MemBarStoreStore or
1724 // stronger) is already added at exit of initializer, also no need
1725 // for a MemBarStoreStore. Otherwise we need a MemBarStoreStore
1726 // so that stores that initialize this object can't be reordered
1727 // with a subsequent store that makes this object accessible by
1728 // other threads.
1729 // Other threads include java threads and JVM internal threads
1730 // (for example concurrent GC threads). Current concurrent GC
1731 // implementation: G1 will not scan newly created object,
1732 // so it's safe to skip storestore barrier when allocation does
1733 // not escape.
1734 if (!alloc->does_not_escape_thread() &&
1735 !alloc->is_allocation_MemBar_redundant() &&
1736 (init == nullptr || !init->is_complete_with_arraycopy())) {
1737 if (init == nullptr || init->req() < InitializeNode::RawStores) {
1738 // No InitializeNode or no stores captured by zeroing
1739 // elimination. Simply add the MemBarStoreStore after object
1740 // initialization.
1741 // What we want is to prevent the compiler and the CPU from re-ordering the stores that initialize this object
1742 // with subsequent stores to any slice. As a consequence, this MemBar should capture the entire memory state at
1743 // this point in the IR and produce a new memory state that should cover all slices. However, the Initialize node
1744 // only captures/produces a partial memory state making it complicated to insert such a MemBar. Because
1745 // re-ordering by the compiler can't happen by construction (a later Store that publishes the just allocated
1746 // object reference is indirectly control dependent on the Initialize node), preventing reordering by the CPU is
1747 // sufficient. For that a MemBar on the raw memory slice is good enough.
1748 // If init is null, this allocation does have an InitializeNode but this logic can't locate it (see comment in
1749 // PhaseMacroExpand::initialize_object()).
1750 MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxRaw);
1751 transform_later(mb);
1752
1753 mb->init_req(TypeFunc::Memory, fast_oop_rawmem);
1754 mb->init_req(TypeFunc::Control, fast_oop_ctrl);
1755 fast_oop_ctrl = new ProjNode(mb, TypeFunc::Control);
1756 transform_later(fast_oop_ctrl);
1757 fast_oop_rawmem = new ProjNode(mb, TypeFunc::Memory);
1758 transform_later(fast_oop_rawmem);
1759 } else {
1760 // Add the MemBarStoreStore after the InitializeNode so that
1761 // all stores performing the initialization that were moved
1762 // before the InitializeNode happen before the storestore
1763 // barrier.
1764
1765 Node* init_ctrl = init->proj_out_or_null(TypeFunc::Control);
1766
1767 // See comment above that explains why a raw memory MemBar is good enough.
1768 MemBarNode* mb = MemBarNode::make(C, Op_MemBarStoreStore, Compile::AliasIdxRaw);
1769 transform_later(mb);
1770
1771 Node* ctrl = new ProjNode(init, TypeFunc::Control);
1772 transform_later(ctrl);
1773 Node* old_raw_mem_proj = nullptr;
1774 auto find_raw_mem = [&](ProjNode* proj) {
1775 if (C->get_alias_index(proj->adr_type()) == Compile::AliasIdxRaw) {
1776 assert(old_raw_mem_proj == nullptr, "only one expected");
1777 old_raw_mem_proj = proj;
1778 }
1779 };
1780 init->for_each_proj(find_raw_mem, TypeFunc::Memory);
1781 assert(old_raw_mem_proj != nullptr, "should have found raw mem Proj");
1782 Node* raw_mem_proj = new ProjNode(init, TypeFunc::Memory);
1783 transform_later(raw_mem_proj);
1784
1785 // The MemBarStoreStore depends on control and memory coming
1786 // from the InitializeNode
1787 mb->init_req(TypeFunc::Memory, raw_mem_proj);
1788 mb->init_req(TypeFunc::Control, ctrl);
1789
1790 ctrl = new ProjNode(mb, TypeFunc::Control);
1791 transform_later(ctrl);
1792 Node* mem = new ProjNode(mb, TypeFunc::Memory);
1793 transform_later(mem);
1794
1795 // All nodes that depended on the InitializeNode for control
1796 // and memory must now depend on the MemBarNode that itself
1797 // depends on the InitializeNode
1798 if (init_ctrl != nullptr) {
1799 _igvn.replace_node(init_ctrl, ctrl);
1800 }
1801 _igvn.replace_node(old_raw_mem_proj, mem);
1802 }
1803 }
1804 }
1805
1806 void PhaseMacroExpand::expand_dtrace_alloc_probe(AllocateNode* alloc, Node* oop,
1807 Node*& ctrl, Node*& rawmem) {
1808 if (C->env()->dtrace_alloc_probes()) {
1809 // Slow-path call
1810 int size = TypeFunc::Parms + 2;
1811 CallLeafNode *call = new CallLeafNode(OptoRuntime::dtrace_object_alloc_Type(),
1812 CAST_FROM_FN_PTR(address,
1813 static_cast<int (*)(JavaThread*, oopDesc*)>(SharedRuntime::dtrace_object_alloc)),
1814 "dtrace_object_alloc",
1815 TypeRawPtr::BOTTOM);
1816
1817 // Get base of thread-local storage area
1818 Node* thread = new ThreadLocalNode();
1819 transform_later(thread);
1820
1821 call->init_req(TypeFunc::Parms + 0, thread);
1822 call->init_req(TypeFunc::Parms + 1, oop);
1823 call->init_req(TypeFunc::Control, ctrl);
1824 call->init_req(TypeFunc::I_O , top()); // does no i/o
1825 call->init_req(TypeFunc::Memory , rawmem);
1826 call->init_req(TypeFunc::ReturnAdr, alloc->in(TypeFunc::ReturnAdr));
1827 call->init_req(TypeFunc::FramePtr, alloc->in(TypeFunc::FramePtr));
1828 transform_later(call);
1829 ctrl = new ProjNode(call, TypeFunc::Control);
1830 transform_later(ctrl);
1831 rawmem = new ProjNode(call, TypeFunc::Memory);
1832 transform_later(rawmem);
1833 }
1834 }
1835
1836 // Helper for PhaseMacroExpand::expand_allocate_common.
1837 // Initializes the newly-allocated storage.
1838 Node*
1839 PhaseMacroExpand::initialize_object(AllocateNode* alloc,
1840 Node* control, Node* rawmem, Node* object,
1841 Node* klass_node, Node* length,
1842 Node* size_in_bytes) {
1843 InitializeNode* init = alloc->initialization();
1844 // Store the klass & mark bits
1845 Node* mark_node = alloc->make_ideal_mark(&_igvn, control, rawmem);
1846 if (!mark_node->is_Con()) {
1847 transform_later(mark_node);
1848 }
1849 rawmem = make_store_raw(control, rawmem, object, oopDesc::mark_offset_in_bytes(), mark_node, TypeX_X->basic_type());
1850
1851 if (!UseCompactObjectHeaders) {
1852 rawmem = make_store_raw(control, rawmem, object, oopDesc::klass_offset_in_bytes(), klass_node, T_METADATA);
1853 }
1854 int header_size = alloc->minimum_header_size(); // conservatively small
1855
1856 // Array length
1857 if (length != nullptr) { // Arrays need length field
1858 rawmem = make_store_raw(control, rawmem, object, arrayOopDesc::length_offset_in_bytes(), length, T_INT);
1859 // conservatively small header size:
1860 header_size = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1861 if (_igvn.type(klass_node)->isa_aryklassptr()) { // we know the exact header size in most cases:
1862 BasicType elem = _igvn.type(klass_node)->is_klassptr()->as_instance_type()->isa_aryptr()->elem()->array_element_basic_type();
1863 if (is_reference_type(elem, true)) {
1864 elem = T_OBJECT;
1865 }
1866 header_size = Klass::layout_helper_header_size(Klass::array_layout_helper(elem));
1867 }
1868 }
1869
1870 // Clear the object body, if necessary.
1871 if (init == nullptr) {
1872 // The init has somehow disappeared; be cautious and clear everything.
1873 //
1874 // This can happen if a node is allocated but an uncommon trap occurs
1875 // immediately. In this case, the Initialize gets associated with the
1876 // trap, and may be placed in a different (outer) loop, if the Allocate
1877 // is in a loop. If (this is rare) the inner loop gets unrolled, then
1878 // there can be two Allocates to one Initialize. The answer in all these
1879 // edge cases is safety first. It is always safe to clear immediately
1880 // within an Allocate, and then (maybe or maybe not) clear some more later.
1881 if (!(UseTLAB && ZeroTLAB)) {
1882 rawmem = ClearArrayNode::clear_memory(control, rawmem, object,
1883 header_size, size_in_bytes,
1884 true,
1885 &_igvn);
1886 }
1887 } else {
1888 if (!init->is_complete()) {
1889 // Try to win by zeroing only what the init does not store.
1890 // We can also try to do some peephole optimizations,
1891 // such as combining some adjacent subword stores.
1892 rawmem = init->complete_stores(control, rawmem, object,
1893 header_size, size_in_bytes, &_igvn);
1894 }
1895 // We have no more use for this link, since the AllocateNode goes away:
1896 init->set_req(InitializeNode::RawAddress, top());
1897 // (If we keep the link, it just confuses the register allocator,
1898 // who thinks he sees a real use of the address by the membar.)
1899 }
1900
1901 return rawmem;
1902 }
1903
1904 // Generate prefetch instructions for next allocations.
1905 Node* PhaseMacroExpand::prefetch_allocation(Node* i_o, Node*& needgc_false,
1906 Node*& contended_phi_rawmem,
1907 Node* old_eden_top, Node* new_eden_top,
1908 intx lines) {
1909 enum { fall_in_path = 1, pf_path = 2 };
1910 if (UseTLAB && AllocatePrefetchStyle == 2) {
1911 // Generate prefetch allocation with watermark check.
1912 // As an allocation hits the watermark, we will prefetch starting
1913 // at a "distance" away from watermark.
1914
1915 Node* pf_region = new RegionNode(3);
1916 Node* pf_phi_rawmem = new PhiNode(pf_region, Type::MEMORY,
1917 TypeRawPtr::BOTTOM);
1918 // I/O is used for Prefetch
1919 Node* pf_phi_abio = new PhiNode(pf_region, Type::ABIO);
1920
1921 Node* thread = new ThreadLocalNode();
1922 transform_later(thread);
1923
1924 Node* eden_pf_adr = AddPNode::make_off_heap(thread,
1925 _igvn.MakeConX(in_bytes(JavaThread::tlab_pf_top_offset())));
1926 transform_later(eden_pf_adr);
1927
1928 Node* old_pf_wm = new LoadPNode(needgc_false,
1929 contended_phi_rawmem, eden_pf_adr,
1930 TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,
1931 MemNode::unordered);
1932 transform_later(old_pf_wm);
1933
1934 // check against new_eden_top
1935 Node* need_pf_cmp = new CmpPNode(new_eden_top, old_pf_wm);
1936 transform_later(need_pf_cmp);
1937 Node* need_pf_bol = new BoolNode(need_pf_cmp, BoolTest::ge);
1938 transform_later(need_pf_bol);
1939 IfNode* need_pf_iff = new IfNode(needgc_false, need_pf_bol,
1940 PROB_UNLIKELY_MAG(4), COUNT_UNKNOWN);
1941 transform_later(need_pf_iff);
1942
1943 // true node, add prefetchdistance
1944 Node* need_pf_true = new IfTrueNode(need_pf_iff);
1945 transform_later(need_pf_true);
1946
1947 Node* need_pf_false = new IfFalseNode(need_pf_iff);
1948 transform_later(need_pf_false);
1949
1950 Node* new_pf_wmt = AddPNode::make_off_heap(old_pf_wm,
1951 _igvn.MakeConX(AllocatePrefetchDistance));
1952 transform_later(new_pf_wmt);
1953 new_pf_wmt->set_req(0, need_pf_true);
1954
1955 Node* store_new_wmt = new StorePNode(need_pf_true,
1956 contended_phi_rawmem, eden_pf_adr,
1957 TypeRawPtr::BOTTOM, new_pf_wmt,
1958 MemNode::unordered);
1959 transform_later(store_new_wmt);
1960
1961 // adding prefetches
1962 pf_phi_abio->init_req(fall_in_path, i_o);
1963
1964 Node* prefetch_adr;
1965 Node* prefetch;
1966 uint step_size = AllocatePrefetchStepSize;
1967 uint distance = 0;
1968
1969 for (intx i = 0; i < lines; i++) {
1970 prefetch_adr = AddPNode::make_off_heap(new_pf_wmt,
1971 _igvn.MakeConX(distance));
1972 transform_later(prefetch_adr);
1973 prefetch = new PrefetchAllocationNode(i_o, prefetch_adr);
1974 transform_later(prefetch);
1975 distance += step_size;
1976 i_o = prefetch;
1977 }
1978 pf_phi_abio->set_req(pf_path, i_o);
1979
1980 pf_region->init_req(fall_in_path, need_pf_false);
1981 pf_region->init_req(pf_path, need_pf_true);
1982
1983 pf_phi_rawmem->init_req(fall_in_path, contended_phi_rawmem);
1984 pf_phi_rawmem->init_req(pf_path, store_new_wmt);
1985
1986 transform_later(pf_region);
1987 transform_later(pf_phi_rawmem);
1988 transform_later(pf_phi_abio);
1989
1990 needgc_false = pf_region;
1991 contended_phi_rawmem = pf_phi_rawmem;
1992 i_o = pf_phi_abio;
1993 } else if (UseTLAB && AllocatePrefetchStyle == 3) {
1994 // Insert a prefetch instruction for each allocation.
1995 // This code is used to generate 1 prefetch instruction per cache line.
1996
1997 // Generate several prefetch instructions.
1998 uint step_size = AllocatePrefetchStepSize;
1999 uint distance = AllocatePrefetchDistance;
2000
2001 // Next cache address.
2002 Node* cache_adr = AddPNode::make_off_heap(old_eden_top,
2003 _igvn.MakeConX(step_size + distance));
2004 transform_later(cache_adr);
2005 cache_adr = new CastP2XNode(needgc_false, cache_adr);
2006 transform_later(cache_adr);
2007 // Address is aligned to execute prefetch to the beginning of cache line size.
2008 Node* mask = _igvn.MakeConX(~(intptr_t)(step_size-1));
2009 cache_adr = new AndXNode(cache_adr, mask);
2010 transform_later(cache_adr);
2011 cache_adr = new CastX2PNode(cache_adr);
2012 transform_later(cache_adr);
2013
2014 // Prefetch
2015 Node* prefetch = new PrefetchAllocationNode(contended_phi_rawmem, cache_adr);
2016 prefetch->set_req(0, needgc_false);
2017 transform_later(prefetch);
2018 contended_phi_rawmem = prefetch;
2019 Node* prefetch_adr;
2020 distance = step_size;
2021 for (intx i = 1; i < lines; i++) {
2022 prefetch_adr = AddPNode::make_off_heap(cache_adr,
2023 _igvn.MakeConX(distance));
2024 transform_later(prefetch_adr);
2025 prefetch = new PrefetchAllocationNode(contended_phi_rawmem, prefetch_adr);
2026 transform_later(prefetch);
2027 distance += step_size;
2028 contended_phi_rawmem = prefetch;
2029 }
2030 } else if (AllocatePrefetchStyle > 0) {
2031 // Insert a prefetch for each allocation only on the fast-path
2032 Node* prefetch_adr;
2033 Node* prefetch;
2034 // Generate several prefetch instructions.
2035 uint step_size = AllocatePrefetchStepSize;
2036 uint distance = AllocatePrefetchDistance;
2037 for (intx i = 0; i < lines; i++) {
2038 prefetch_adr = AddPNode::make_off_heap(new_eden_top,
2039 _igvn.MakeConX(distance));
2040 transform_later(prefetch_adr);
2041 prefetch = new PrefetchAllocationNode(i_o, prefetch_adr);
2042 // Do not let it float too high, since if eden_top == eden_end,
2043 // both might be null.
2044 if (i == 0) { // Set control for first prefetch, next follows it
2045 prefetch->init_req(0, needgc_false);
2046 }
2047 transform_later(prefetch);
2048 distance += step_size;
2049 i_o = prefetch;
2050 }
2051 }
2052 return i_o;
2053 }
2054
2055
2056 void PhaseMacroExpand::expand_allocate(AllocateNode *alloc) {
2057 expand_allocate_common(alloc, nullptr,
2058 OptoRuntime::new_instance_Type(),
2059 OptoRuntime::new_instance_Java(), nullptr);
2060 }
2061
2062 void PhaseMacroExpand::expand_allocate_array(AllocateArrayNode *alloc) {
2063 Node* length = alloc->in(AllocateNode::ALength);
2064 Node* valid_length_test = alloc->in(AllocateNode::ValidLengthTest);
2065 InitializeNode* init = alloc->initialization();
2066 Node* klass_node = alloc->in(AllocateNode::KlassNode);
2067 const TypeAryKlassPtr* ary_klass_t = _igvn.type(klass_node)->isa_aryklassptr();
2068 address slow_call_address; // Address of slow call
2069 if (init != nullptr && init->is_complete_with_arraycopy() &&
2070 ary_klass_t && ary_klass_t->elem()->isa_klassptr() == nullptr) {
2071 // Don't zero type array during slow allocation in VM since
2072 // it will be initialized later by arraycopy in compiled code.
2073 slow_call_address = OptoRuntime::new_array_nozero_Java();
2074 } else {
2075 slow_call_address = OptoRuntime::new_array_Java();
2076 }
2077 expand_allocate_common(alloc, length,
2078 OptoRuntime::new_array_Type(),
2079 slow_call_address, valid_length_test);
2080 }
2081
2082 //-------------------mark_eliminated_box----------------------------------
2083 //
2084 // During EA obj may point to several objects but after few ideal graph
2085 // transformations (CCP) it may point to only one non escaping object
2086 // (but still using phi), corresponding locks and unlocks will be marked
2087 // for elimination. Later obj could be replaced with a new node (new phi)
2088 // and which does not have escape information. And later after some graph
2089 // reshape other locks and unlocks (which were not marked for elimination
2090 // before) are connected to this new obj (phi) but they still will not be
2091 // marked for elimination since new obj has no escape information.
2092 // Mark all associated (same box and obj) lock and unlock nodes for
2093 // elimination if some of them marked already.
2094 void PhaseMacroExpand::mark_eliminated_box(Node* box, Node* obj) {
2095 BoxLockNode* oldbox = box->as_BoxLock();
2096 if (oldbox->is_eliminated()) {
2097 return; // This BoxLock node was processed already.
2098 }
2099 assert(!oldbox->is_unbalanced(), "this should not be called for unbalanced region");
2100 // New implementation (EliminateNestedLocks) has separate BoxLock
2101 // node for each locked region so mark all associated locks/unlocks as
2102 // eliminated even if different objects are referenced in one locked region
2103 // (for example, OSR compilation of nested loop inside locked scope).
2104 if (EliminateNestedLocks ||
2105 oldbox->as_BoxLock()->is_simple_lock_region(nullptr, obj, nullptr)) {
2106 // Box is used only in one lock region. Mark this box as eliminated.
2107 oldbox->set_local(); // This verifies correct state of BoxLock
2108 _igvn.hash_delete(oldbox);
2109 oldbox->set_eliminated(); // This changes box's hash value
2110 _igvn.hash_insert(oldbox);
2111
2112 for (uint i = 0; i < oldbox->outcnt(); i++) {
2113 Node* u = oldbox->raw_out(i);
2114 if (u->is_AbstractLock() && !u->as_AbstractLock()->is_non_esc_obj()) {
2115 AbstractLockNode* alock = u->as_AbstractLock();
2116 // Check lock's box since box could be referenced by Lock's debug info.
2117 if (alock->box_node() == oldbox) {
2118 // Mark eliminated all related locks and unlocks.
2119 #ifdef ASSERT
2120 alock->log_lock_optimization(C, "eliminate_lock_set_non_esc4");
2121 #endif
2122 alock->set_non_esc_obj();
2123 }
2124 }
2125 }
2126 return;
2127 }
2128
2129 // Create new "eliminated" BoxLock node and use it in monitor debug info
2130 // instead of oldbox for the same object.
2131 BoxLockNode* newbox = oldbox->clone()->as_BoxLock();
2132
2133 // Note: BoxLock node is marked eliminated only here and it is used
2134 // to indicate that all associated lock and unlock nodes are marked
2135 // for elimination.
2136 newbox->set_local(); // This verifies correct state of BoxLock
2137 newbox->set_eliminated();
2138 transform_later(newbox);
2139
2140 // Replace old box node with new box for all users of the same object.
2141 for (uint i = 0; i < oldbox->outcnt();) {
2142 bool next_edge = true;
2143
2144 Node* u = oldbox->raw_out(i);
2145 if (u->is_AbstractLock()) {
2146 AbstractLockNode* alock = u->as_AbstractLock();
2147 if (alock->box_node() == oldbox && alock->obj_node()->eqv_uncast(obj)) {
2148 // Replace Box and mark eliminated all related locks and unlocks.
2149 #ifdef ASSERT
2150 alock->log_lock_optimization(C, "eliminate_lock_set_non_esc5");
2151 #endif
2152 alock->set_non_esc_obj();
2153 _igvn.rehash_node_delayed(alock);
2154 alock->set_box_node(newbox);
2155 next_edge = false;
2156 }
2157 }
2158 if (u->is_FastLock() && u->as_FastLock()->obj_node()->eqv_uncast(obj)) {
2159 FastLockNode* flock = u->as_FastLock();
2160 assert(flock->box_node() == oldbox, "sanity");
2161 _igvn.rehash_node_delayed(flock);
2162 flock->set_box_node(newbox);
2163 next_edge = false;
2164 }
2165
2166 // Replace old box in monitor debug info.
2167 if (u->is_SafePoint() && u->as_SafePoint()->jvms()) {
2168 SafePointNode* sfn = u->as_SafePoint();
2169 JVMState* youngest_jvms = sfn->jvms();
2170 int max_depth = youngest_jvms->depth();
2171 for (int depth = 1; depth <= max_depth; depth++) {
2172 JVMState* jvms = youngest_jvms->of_depth(depth);
2173 int num_mon = jvms->nof_monitors();
2174 // Loop over monitors
2175 for (int idx = 0; idx < num_mon; idx++) {
2176 Node* obj_node = sfn->monitor_obj(jvms, idx);
2177 Node* box_node = sfn->monitor_box(jvms, idx);
2178 if (box_node == oldbox && obj_node->eqv_uncast(obj)) {
2179 int j = jvms->monitor_box_offset(idx);
2180 _igvn.replace_input_of(u, j, newbox);
2181 next_edge = false;
2182 }
2183 }
2184 }
2185 }
2186 if (next_edge) i++;
2187 }
2188 }
2189
2190 //-----------------------mark_eliminated_locking_nodes-----------------------
2191 void PhaseMacroExpand::mark_eliminated_locking_nodes(AbstractLockNode *alock) {
2192 if (!alock->is_balanced()) {
2193 return; // Can't do any more elimination for this locking region
2194 }
2195 if (EliminateNestedLocks) {
2196 if (alock->is_nested()) {
2197 assert(alock->box_node()->as_BoxLock()->is_eliminated(), "sanity");
2198 return;
2199 } else if (!alock->is_non_esc_obj()) { // Not eliminated or coarsened
2200 // Only Lock node has JVMState needed here.
2201 // Not that preceding claim is documented anywhere else.
2202 if (alock->jvms() != nullptr) {
2203 if (alock->as_Lock()->is_nested_lock_region()) {
2204 // Mark eliminated related nested locks and unlocks.
2205 Node* obj = alock->obj_node();
2206 BoxLockNode* box_node = alock->box_node()->as_BoxLock();
2207 assert(!box_node->is_eliminated(), "should not be marked yet");
2208 // Note: BoxLock node is marked eliminated only here
2209 // and it is used to indicate that all associated lock
2210 // and unlock nodes are marked for elimination.
2211 box_node->set_eliminated(); // Box's hash is always NO_HASH here
2212 for (uint i = 0; i < box_node->outcnt(); i++) {
2213 Node* u = box_node->raw_out(i);
2214 if (u->is_AbstractLock()) {
2215 alock = u->as_AbstractLock();
2216 if (alock->box_node() == box_node) {
2217 // Verify that this Box is referenced only by related locks.
2218 assert(alock->obj_node()->eqv_uncast(obj), "");
2219 // Mark all related locks and unlocks.
2220 #ifdef ASSERT
2221 alock->log_lock_optimization(C, "eliminate_lock_set_nested");
2222 #endif
2223 alock->set_nested();
2224 }
2225 }
2226 }
2227 } else {
2228 #ifdef ASSERT
2229 alock->log_lock_optimization(C, "eliminate_lock_NOT_nested_lock_region");
2230 if (C->log() != nullptr)
2231 alock->as_Lock()->is_nested_lock_region(C); // rerun for debugging output
2232 #endif
2233 }
2234 }
2235 return;
2236 }
2237 // Process locks for non escaping object
2238 assert(alock->is_non_esc_obj(), "");
2239 } // EliminateNestedLocks
2240
2241 if (alock->is_non_esc_obj()) { // Lock is used for non escaping object
2242 // Look for all locks of this object and mark them and
2243 // corresponding BoxLock nodes as eliminated.
2244 Node* obj = alock->obj_node();
2245 for (uint j = 0; j < obj->outcnt(); j++) {
2246 Node* o = obj->raw_out(j);
2247 if (o->is_AbstractLock() &&
2248 o->as_AbstractLock()->obj_node()->eqv_uncast(obj)) {
2249 alock = o->as_AbstractLock();
2250 Node* box = alock->box_node();
2251 // Replace old box node with new eliminated box for all users
2252 // of the same object and mark related locks as eliminated.
2253 mark_eliminated_box(box, obj);
2254 }
2255 }
2256 }
2257 }
2258
2259 // we have determined that this lock/unlock can be eliminated, we simply
2260 // eliminate the node without expanding it.
2261 //
2262 // Note: The membar's associated with the lock/unlock are currently not
2263 // eliminated. This should be investigated as a future enhancement.
2264 //
2265 bool PhaseMacroExpand::eliminate_locking_node(AbstractLockNode *alock) {
2266
2267 if (!alock->is_eliminated()) {
2268 return false;
2269 }
2270 #ifdef ASSERT
2271 if (!alock->is_coarsened()) {
2272 // Check that new "eliminated" BoxLock node is created.
2273 BoxLockNode* oldbox = alock->box_node()->as_BoxLock();
2274 assert(oldbox->is_eliminated(), "should be done already");
2275 }
2276 #endif
2277
2278 alock->log_lock_optimization(C, "eliminate_lock");
2279
2280 #ifndef PRODUCT
2281 if (PrintEliminateLocks) {
2282 tty->print_cr("++++ Eliminated: %d %s '%s'", alock->_idx, (alock->is_Lock() ? "Lock" : "Unlock"), alock->kind_as_string());
2283 }
2284 #endif
2285
2286 Node* mem = alock->in(TypeFunc::Memory);
2287 Node* ctrl = alock->in(TypeFunc::Control);
2288 guarantee(ctrl != nullptr, "missing control projection, cannot replace_node() with null");
2289
2290 alock->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2291 // There are 2 projections from the lock. The lock node will
2292 // be deleted when its last use is subsumed below.
2293 assert(alock->outcnt() == 2 &&
2294 _callprojs.fallthrough_proj != nullptr &&
2295 _callprojs.fallthrough_memproj != nullptr,
2296 "Unexpected projections from Lock/Unlock");
2297
2298 Node* fallthroughproj = _callprojs.fallthrough_proj;
2299 Node* memproj_fallthrough = _callprojs.fallthrough_memproj;
2300
2301 // The memory projection from a lock/unlock is RawMem
2302 // The input to a Lock is merged memory, so extract its RawMem input
2303 // (unless the MergeMem has been optimized away.)
2304 if (alock->is_Lock()) {
2305 // Search for MemBarAcquireLock node and delete it also.
2306 MemBarNode* membar = fallthroughproj->unique_ctrl_out()->as_MemBar();
2307 assert(membar != nullptr && membar->Opcode() == Op_MemBarAcquireLock, "");
2308 Node* ctrlproj = membar->proj_out(TypeFunc::Control);
2309 Node* memproj = membar->proj_out(TypeFunc::Memory);
2310 _igvn.replace_node(ctrlproj, fallthroughproj);
2311 _igvn.replace_node(memproj, memproj_fallthrough);
2312
2313 // Delete FastLock node also if this Lock node is unique user
2314 // (a loop peeling may clone a Lock node).
2315 Node* flock = alock->as_Lock()->fastlock_node();
2316 if (flock->outcnt() == 1) {
2317 assert(flock->unique_out() == alock, "sanity");
2318 _igvn.replace_node(flock, top());
2319 }
2320 }
2321
2322 // Search for MemBarReleaseLock node and delete it also.
2323 if (alock->is_Unlock() && ctrl->is_Proj() && ctrl->in(0)->is_MemBar()) {
2324 MemBarNode* membar = ctrl->in(0)->as_MemBar();
2325 assert(membar->Opcode() == Op_MemBarReleaseLock &&
2326 mem->is_Proj() && membar == mem->in(0), "");
2327 _igvn.replace_node(fallthroughproj, ctrl);
2328 _igvn.replace_node(memproj_fallthrough, mem);
2329 fallthroughproj = ctrl;
2330 memproj_fallthrough = mem;
2331 ctrl = membar->in(TypeFunc::Control);
2332 mem = membar->in(TypeFunc::Memory);
2333 }
2334
2335 _igvn.replace_node(fallthroughproj, ctrl);
2336 _igvn.replace_node(memproj_fallthrough, mem);
2337 return true;
2338 }
2339
2340
2341 //------------------------------expand_lock_node----------------------
2342 void PhaseMacroExpand::expand_lock_node(LockNode *lock) {
2343
2344 Node* ctrl = lock->in(TypeFunc::Control);
2345 Node* mem = lock->in(TypeFunc::Memory);
2346 Node* obj = lock->obj_node();
2347 Node* box = lock->box_node();
2348 Node* flock = lock->fastlock_node();
2349
2350 assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2351
2352 // Make the merge point
2353 Node *region;
2354 Node *mem_phi;
2355 Node *slow_path;
2356
2357 region = new RegionNode(3);
2358 // create a Phi for the memory state
2359 mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2360
2361 // Optimize test; set region slot 2
2362 slow_path = opt_bits_test(ctrl, region, 2, flock);
2363 mem_phi->init_req(2, mem);
2364
2365 // Make slow path call
2366 CallNode* call = make_slow_call(lock, OptoRuntime::complete_monitor_enter_Type(),
2367 OptoRuntime::complete_monitor_locking_Java(), nullptr, slow_path,
2368 obj, box, nullptr);
2369
2370 call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2371
2372 // Slow path can only throw asynchronous exceptions, which are always
2373 // de-opted. So the compiler thinks the slow-call can never throw an
2374 // exception. If it DOES throw an exception we would need the debug
2375 // info removed first (since if it throws there is no monitor).
2376 assert(_callprojs.fallthrough_ioproj == nullptr && _callprojs.catchall_ioproj == nullptr &&
2377 _callprojs.catchall_memproj == nullptr && _callprojs.catchall_catchproj == nullptr, "Unexpected projection from Lock");
2378
2379 // Capture slow path
2380 // disconnect fall-through projection from call and create a new one
2381 // hook up users of fall-through projection to region
2382 Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2383 transform_later(slow_ctrl);
2384 _igvn.hash_delete(_callprojs.fallthrough_proj);
2385 _callprojs.fallthrough_proj->disconnect_inputs(C);
2386 region->init_req(1, slow_ctrl);
2387 // region inputs are now complete
2388 transform_later(region);
2389 _igvn.replace_node(_callprojs.fallthrough_proj, region);
2390
2391 Node *memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2392
2393 mem_phi->init_req(1, memproj);
2394
2395 transform_later(mem_phi);
2396
2397 _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2398 }
2399
2400 //------------------------------expand_unlock_node----------------------
2401 void PhaseMacroExpand::expand_unlock_node(UnlockNode *unlock) {
2402
2403 Node* ctrl = unlock->in(TypeFunc::Control);
2404 Node* mem = unlock->in(TypeFunc::Memory);
2405 Node* obj = unlock->obj_node();
2406 Node* box = unlock->box_node();
2407
2408 assert(!box->as_BoxLock()->is_eliminated(), "sanity");
2409
2410 // No need for a null check on unlock
2411
2412 // Make the merge point
2413 Node* region = new RegionNode(3);
2414
2415 FastUnlockNode *funlock = new FastUnlockNode( ctrl, obj, box );
2416 funlock = transform_later( funlock )->as_FastUnlock();
2417 // Optimize test; set region slot 2
2418 Node *slow_path = opt_bits_test(ctrl, region, 2, funlock);
2419 Node *thread = transform_later(new ThreadLocalNode());
2420
2421 CallNode *call = make_slow_call((CallNode *) unlock, OptoRuntime::complete_monitor_exit_Type(),
2422 CAST_FROM_FN_PTR(address, SharedRuntime::complete_monitor_unlocking_C),
2423 "complete_monitor_unlocking_C", slow_path, obj, box, thread);
2424
2425 call->extract_projections(&_callprojs, false /*separate_io_proj*/, false /*do_asserts*/);
2426 assert(_callprojs.fallthrough_ioproj == nullptr && _callprojs.catchall_ioproj == nullptr &&
2427 _callprojs.catchall_memproj == nullptr && _callprojs.catchall_catchproj == nullptr, "Unexpected projection from Lock");
2428
2429 // No exceptions for unlocking
2430 // Capture slow path
2431 // disconnect fall-through projection from call and create a new one
2432 // hook up users of fall-through projection to region
2433 Node *slow_ctrl = _callprojs.fallthrough_proj->clone();
2434 transform_later(slow_ctrl);
2435 _igvn.hash_delete(_callprojs.fallthrough_proj);
2436 _callprojs.fallthrough_proj->disconnect_inputs(C);
2437 region->init_req(1, slow_ctrl);
2438 // region inputs are now complete
2439 transform_later(region);
2440 _igvn.replace_node(_callprojs.fallthrough_proj, region);
2441
2442 if (_callprojs.fallthrough_memproj != nullptr) {
2443 // create a Phi for the memory state
2444 Node* mem_phi = new PhiNode( region, Type::MEMORY, TypeRawPtr::BOTTOM);
2445 Node* memproj = transform_later(new ProjNode(call, TypeFunc::Memory));
2446 mem_phi->init_req(1, memproj);
2447 mem_phi->init_req(2, mem);
2448 transform_later(mem_phi);
2449 _igvn.replace_node(_callprojs.fallthrough_memproj, mem_phi);
2450 }
2451 }
2452
2453 void PhaseMacroExpand::expand_subtypecheck_node(SubTypeCheckNode *check) {
2454 assert(check->in(SubTypeCheckNode::Control) == nullptr, "should be pinned");
2455 Node* bol = check->unique_out();
2456 Node* obj_or_subklass = check->in(SubTypeCheckNode::ObjOrSubKlass);
2457 Node* superklass = check->in(SubTypeCheckNode::SuperKlass);
2458 assert(bol->is_Bool() && bol->as_Bool()->_test._test == BoolTest::ne, "unexpected bool node");
2459
2460 for (DUIterator_Last imin, i = bol->last_outs(imin); i >= imin; --i) {
2461 Node* iff = bol->last_out(i);
2462 assert(iff->is_If(), "where's the if?");
2463
2464 if (iff->in(0)->is_top()) {
2465 _igvn.replace_input_of(iff, 1, C->top());
2466 continue;
2467 }
2468
2469 IfTrueNode* iftrue = iff->as_If()->true_proj();
2470 IfFalseNode* iffalse = iff->as_If()->false_proj();
2471 Node* ctrl = iff->in(0);
2472
2473 Node* subklass = nullptr;
2474 if (_igvn.type(obj_or_subklass)->isa_klassptr()) {
2475 subklass = obj_or_subklass;
2476 } else {
2477 Node* k_adr = basic_plus_adr(obj_or_subklass, oopDesc::klass_offset_in_bytes());
2478 subklass = _igvn.transform(LoadKlassNode::make(_igvn, C->immutable_memory(), k_adr, TypeInstPtr::KLASS));
2479 }
2480
2481 Node* not_subtype_ctrl = Phase::gen_subtype_check(subklass, superklass, &ctrl, nullptr, _igvn, check->method(), check->bci());
2482
2483 _igvn.replace_input_of(iff, 0, C->top());
2484 _igvn.replace_node(iftrue, not_subtype_ctrl);
2485 _igvn.replace_node(iffalse, ctrl);
2486 }
2487 _igvn.replace_node(check, C->top());
2488 }
2489
2490 // Perform refining of strip mined loop nodes in the macro nodes list.
2491 void PhaseMacroExpand::refine_strip_mined_loop_macro_nodes() {
2492 for (int i = C->macro_count(); i > 0; i--) {
2493 Node* n = C->macro_node(i - 1);
2494 if (n->is_OuterStripMinedLoop()) {
2495 n->as_OuterStripMinedLoop()->adjust_strip_mined_loop(&_igvn);
2496 }
2497 }
2498 }
2499
2500 //---------------------------eliminate_macro_nodes----------------------
2501 // Eliminate scalar replaced allocations and associated locks.
2502 void PhaseMacroExpand::eliminate_macro_nodes() {
2503 if (C->macro_count() == 0)
2504 return;
2505
2506 if (StressMacroElimination) {
2507 C->shuffle_macro_nodes();
2508 }
2509 NOT_PRODUCT(int membar_before = count_MemBar(C);)
2510
2511 // Before elimination may re-mark (change to Nested or NonEscObj)
2512 // all associated (same box and obj) lock and unlock nodes.
2513 int cnt = C->macro_count();
2514 for (int i=0; i < cnt; i++) {
2515 Node *n = C->macro_node(i);
2516 if (n->is_AbstractLock()) { // Lock and Unlock nodes
2517 mark_eliminated_locking_nodes(n->as_AbstractLock());
2518 }
2519 }
2520 // Re-marking may break consistency of Coarsened locks.
2521 if (!C->coarsened_locks_consistent()) {
2522 return; // recompile without Coarsened locks if broken
2523 } else {
2524 // After coarsened locks are eliminated locking regions
2525 // become unbalanced. We should not execute any more
2526 // locks elimination optimizations on them.
2527 C->mark_unbalanced_boxes();
2528 }
2529
2530 // First, attempt to eliminate locks
2531 bool progress = true;
2532 while (progress) {
2533 progress = false;
2534 for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2535 Node* n = C->macro_node(i - 1);
2536 bool success = false;
2537 DEBUG_ONLY(int old_macro_count = C->macro_count();)
2538 if (n->is_AbstractLock()) {
2539 success = eliminate_locking_node(n->as_AbstractLock());
2540 #ifndef PRODUCT
2541 if (success && PrintOptoStatistics) {
2542 AtomicAccess::inc(&PhaseMacroExpand::_monitor_objects_removed_counter);
2543 }
2544 #endif
2545 }
2546 assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2547 progress = progress || success;
2548 if (success) {
2549 C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2550 }
2551 }
2552 }
2553 // Next, attempt to eliminate allocations
2554 progress = true;
2555 while (progress) {
2556 progress = false;
2557 for (int i = C->macro_count(); i > 0; i = MIN2(i - 1, C->macro_count())) { // more than 1 element can be eliminated at once
2558 Node* n = C->macro_node(i - 1);
2559 bool success = false;
2560 DEBUG_ONLY(int old_macro_count = C->macro_count();)
2561 switch (n->class_id()) {
2562 case Node::Class_Allocate:
2563 case Node::Class_AllocateArray:
2564 success = eliminate_allocate_node(n->as_Allocate());
2565 #ifndef PRODUCT
2566 if (success && PrintOptoStatistics) {
2567 AtomicAccess::inc(&PhaseMacroExpand::_objs_scalar_replaced_counter);
2568 }
2569 #endif
2570 break;
2571 case Node::Class_CallStaticJava:
2572 success = eliminate_boxing_node(n->as_CallStaticJava());
2573 break;
2574 case Node::Class_Lock:
2575 case Node::Class_Unlock:
2576 assert(!n->as_AbstractLock()->is_eliminated(), "sanity");
2577 break;
2578 case Node::Class_ArrayCopy:
2579 break;
2580 case Node::Class_OuterStripMinedLoop:
2581 break;
2582 case Node::Class_SubTypeCheck:
2583 break;
2584 case Node::Class_Opaque1:
2585 break;
2586 default:
2587 assert(n->Opcode() == Op_LoopLimit ||
2588 n->Opcode() == Op_ModD ||
2589 n->Opcode() == Op_ModF ||
2590 n->Opcode() == Op_PowD ||
2591 n->is_OpaqueConstantBool() ||
2592 n->is_OpaqueInitializedAssertionPredicate() ||
2593 n->Opcode() == Op_MaxL ||
2594 n->Opcode() == Op_MinL ||
2595 BarrierSet::barrier_set()->barrier_set_c2()->is_gc_barrier_node(n),
2596 "unknown node type in macro list");
2597 }
2598 assert(success == (C->macro_count() < old_macro_count), "elimination reduces macro count");
2599 progress = progress || success;
2600 if (success) {
2601 C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2602 }
2603 }
2604 }
2605 #ifndef PRODUCT
2606 if (PrintOptoStatistics) {
2607 int membar_after = count_MemBar(C);
2608 AtomicAccess::add(&PhaseMacroExpand::_memory_barriers_removed_counter, membar_before - membar_after);
2609 }
2610 #endif
2611 }
2612
2613 void PhaseMacroExpand::eliminate_opaque_looplimit_macro_nodes() {
2614 if (C->macro_count() == 0) {
2615 return;
2616 }
2617 refine_strip_mined_loop_macro_nodes();
2618 // Eliminate Opaque and LoopLimit nodes. Do it after all loop optimizations.
2619 bool progress = true;
2620 while (progress) {
2621 progress = false;
2622 for (int i = C->macro_count(); i > 0; i--) {
2623 Node* n = C->macro_node(i-1);
2624 bool success = false;
2625 DEBUG_ONLY(int old_macro_count = C->macro_count();)
2626 if (n->Opcode() == Op_LoopLimit) {
2627 // Remove it from macro list and put on IGVN worklist to optimize.
2628 C->remove_macro_node(n);
2629 _igvn._worklist.push(n);
2630 success = true;
2631 } else if (n->Opcode() == Op_CallStaticJava) {
2632 // Remove it from macro list and put on IGVN worklist to optimize.
2633 C->remove_macro_node(n);
2634 _igvn._worklist.push(n);
2635 success = true;
2636 } else if (n->is_Opaque1()) {
2637 _igvn.replace_node(n, n->in(1));
2638 success = true;
2639 } else if (n->is_OpaqueConstantBool()) {
2640 // Tests with OpaqueConstantBool nodes are implicitly known. Replace the node with true/false. In debug builds,
2641 // we leave the test in the graph to have an additional sanity check at runtime. If the test fails (i.e. a bug),
2642 // we will execute a Halt node.
2643 #ifdef ASSERT
2644 _igvn.replace_node(n, n->in(1));
2645 #else
2646 _igvn.replace_node(n, _igvn.intcon(n->as_OpaqueConstantBool()->constant()));
2647 #endif
2648 success = true;
2649 } else if (n->is_OpaqueInitializedAssertionPredicate()) {
2650 // Initialized Assertion Predicates must always evaluate to true. Therefore, we get rid of them in product
2651 // builds as they are useless. In debug builds we keep them as additional verification code. Even though
2652 // loop opts are already over, we want to keep Initialized Assertion Predicates alive as long as possible to
2653 // enable folding of dead control paths within which cast nodes become top after due to impossible types -
2654 // even after loop opts are over. Therefore, we delay the removal of these opaque nodes until now.
2655 #ifdef ASSERT
2656 _igvn.replace_node(n, n->in(1));
2657 #else
2658 _igvn.replace_node(n, _igvn.intcon(1));
2659 #endif // ASSERT
2660 } else if (n->Opcode() == Op_OuterStripMinedLoop) {
2661 C->remove_macro_node(n);
2662 success = true;
2663 } else if (n->Opcode() == Op_MaxL) {
2664 // Since MaxL and MinL are not implemented in the backend, we expand them to
2665 // a CMoveL construct now. At least until here, the type could be computed
2666 // precisely. CMoveL is not so smart, but we can give it at least the best
2667 // type we know abouot n now.
2668 Node* repl = MinMaxNode::signed_max(n->in(1), n->in(2), _igvn.type(n), _igvn);
2669 _igvn.replace_node(n, repl);
2670 success = true;
2671 } else if (n->Opcode() == Op_MinL) {
2672 Node* repl = MinMaxNode::signed_min(n->in(1), n->in(2), _igvn.type(n), _igvn);
2673 _igvn.replace_node(n, repl);
2674 success = true;
2675 }
2676 assert(!success || (C->macro_count() == (old_macro_count - 1)), "elimination must have deleted one node from macro list");
2677 progress = progress || success;
2678 if (success) {
2679 C->print_method(PHASE_AFTER_MACRO_ELIMINATION_STEP, 5, n);
2680 }
2681 }
2682 }
2683 }
2684
2685 //------------------------------expand_macro_nodes----------------------
2686 // Returns true if a failure occurred.
2687 bool PhaseMacroExpand::expand_macro_nodes() {
2688 if (StressMacroExpansion) {
2689 C->shuffle_macro_nodes();
2690 }
2691
2692 // Clean up the graph so we're less likely to hit the maximum node
2693 // limit
2694 _igvn.set_delay_transform(false);
2695 _igvn.optimize();
2696 if (C->failing()) return true;
2697 _igvn.set_delay_transform(true);
2698
2699
2700 // Because we run IGVN after each expansion, some macro nodes may go
2701 // dead and be removed from the list as we iterate over it. Move
2702 // Allocate nodes (processed in a second pass) at the beginning of
2703 // the list and then iterate from the last element of the list until
2704 // an Allocate node is seen. This is robust to random deletion in
2705 // the list due to nodes going dead.
2706 C->sort_macro_nodes();
2707
2708 // expand arraycopy "macro" nodes first
2709 // For ReduceBulkZeroing, we must first process all arraycopy nodes
2710 // before the allocate nodes are expanded.
2711 while (C->macro_count() > 0) {
2712 int macro_count = C->macro_count();
2713 Node * n = C->macro_node(macro_count-1);
2714 assert(n->is_macro(), "only macro nodes expected here");
2715 if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
2716 // node is unreachable, so don't try to expand it
2717 C->remove_macro_node(n);
2718 continue;
2719 }
2720 if (n->is_Allocate()) {
2721 break;
2722 }
2723 // Make sure expansion will not cause node limit to be exceeded.
2724 // Worst case is a macro node gets expanded into about 200 nodes.
2725 // Allow 50% more for optimization.
2726 if (C->check_node_count(300, "out of nodes before macro expansion")) {
2727 return true;
2728 }
2729
2730 DEBUG_ONLY(int old_macro_count = C->macro_count();)
2731 switch (n->class_id()) {
2732 case Node::Class_Lock:
2733 expand_lock_node(n->as_Lock());
2734 break;
2735 case Node::Class_Unlock:
2736 expand_unlock_node(n->as_Unlock());
2737 break;
2738 case Node::Class_ArrayCopy:
2739 expand_arraycopy_node(n->as_ArrayCopy());
2740 break;
2741 case Node::Class_SubTypeCheck:
2742 expand_subtypecheck_node(n->as_SubTypeCheck());
2743 break;
2744 default:
2745 switch (n->Opcode()) {
2746 case Op_ModD:
2747 case Op_ModF:
2748 case Op_PowD: {
2749 CallLeafPureNode* call_macro = n->as_CallLeafPure();
2750 CallLeafPureNode* call = call_macro->inline_call_leaf_pure_node();
2751 _igvn.replace_node(call_macro, call);
2752 transform_later(call);
2753 break;
2754 }
2755 default:
2756 assert(false, "unknown node type in macro list");
2757 }
2758 }
2759 assert(C->macro_count() == (old_macro_count - 1), "expansion must have deleted one node from macro list");
2760 if (C->failing()) return true;
2761 C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
2762
2763 // Clean up the graph so we're less likely to hit the maximum node
2764 // limit
2765 _igvn.set_delay_transform(false);
2766 _igvn.optimize();
2767 if (C->failing()) return true;
2768 _igvn.set_delay_transform(true);
2769 }
2770
2771 // All nodes except Allocate nodes are expanded now. There could be
2772 // new optimization opportunities (such as folding newly created
2773 // load from a just allocated object). Run IGVN.
2774
2775 // expand "macro" nodes
2776 // nodes are removed from the macro list as they are processed
2777 while (C->macro_count() > 0) {
2778 int macro_count = C->macro_count();
2779 Node * n = C->macro_node(macro_count-1);
2780 assert(n->is_macro(), "only macro nodes expected here");
2781 if (_igvn.type(n) == Type::TOP || (n->in(0) != nullptr && n->in(0)->is_top())) {
2782 // node is unreachable, so don't try to expand it
2783 C->remove_macro_node(n);
2784 continue;
2785 }
2786 // Make sure expansion will not cause node limit to be exceeded.
2787 // Worst case is a macro node gets expanded into about 200 nodes.
2788 // Allow 50% more for optimization.
2789 if (C->check_node_count(300, "out of nodes before macro expansion")) {
2790 return true;
2791 }
2792 switch (n->class_id()) {
2793 case Node::Class_Allocate:
2794 expand_allocate(n->as_Allocate());
2795 break;
2796 case Node::Class_AllocateArray:
2797 expand_allocate_array(n->as_AllocateArray());
2798 break;
2799 default:
2800 assert(false, "unknown node type in macro list");
2801 }
2802 assert(C->macro_count() < macro_count, "must have deleted a node from macro list");
2803 if (C->failing()) return true;
2804 C->print_method(PHASE_AFTER_MACRO_EXPANSION_STEP, 5, n);
2805
2806 // Clean up the graph so we're less likely to hit the maximum node
2807 // limit
2808 _igvn.set_delay_transform(false);
2809 _igvn.optimize();
2810 if (C->failing()) return true;
2811 _igvn.set_delay_transform(true);
2812 }
2813
2814 _igvn.set_delay_transform(false);
2815 return false;
2816 }
2817
2818 #ifndef PRODUCT
2819 int PhaseMacroExpand::_objs_scalar_replaced_counter = 0;
2820 int PhaseMacroExpand::_monitor_objects_removed_counter = 0;
2821 int PhaseMacroExpand::_GC_barriers_removed_counter = 0;
2822 int PhaseMacroExpand::_memory_barriers_removed_counter = 0;
2823
2824 void PhaseMacroExpand::print_statistics() {
2825 tty->print("Objects scalar replaced = %d, ", AtomicAccess::load(&_objs_scalar_replaced_counter));
2826 tty->print("Monitor objects removed = %d, ", AtomicAccess::load(&_monitor_objects_removed_counter));
2827 tty->print("GC barriers removed = %d, ", AtomicAccess::load(&_GC_barriers_removed_counter));
2828 tty->print_cr("Memory barriers removed = %d", AtomicAccess::load(&_memory_barriers_removed_counter));
2829 }
2830
2831 int PhaseMacroExpand::count_MemBar(Compile *C) {
2832 if (!PrintOptoStatistics) {
2833 return 0;
2834 }
2835 Unique_Node_List ideal_nodes;
2836 int total = 0;
2837 ideal_nodes.map(C->live_nodes(), nullptr);
2838 ideal_nodes.push(C->root());
2839 for (uint next = 0; next < ideal_nodes.size(); ++next) {
2840 Node* n = ideal_nodes.at(next);
2841 if (n->is_MemBar()) {
2842 total++;
2843 }
2844 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2845 Node* m = n->fast_out(i);
2846 ideal_nodes.push(m);
2847 }
2848 }
2849 return total;
2850 }
2851 #endif