1 /*
2 * Copyright (c) 2015, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright (C) 2022 THL A29 Limited, a Tencent company. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27
28 #include "classfile/javaClasses.hpp"
29 #include "gc/shenandoah/c2/shenandoahSupport.hpp"
30 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
31 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
32 #include "gc/shenandoah/shenandoahForwarding.hpp"
33 #include "gc/shenandoah/shenandoahHeap.hpp"
34 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
35 #include "gc/shenandoah/shenandoahRuntime.hpp"
36 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
37 #include "opto/arraycopynode.hpp"
38 #include "opto/block.hpp"
39 #include "opto/callnode.hpp"
40 #include "opto/castnode.hpp"
41 #include "opto/movenode.hpp"
42 #include "opto/phaseX.hpp"
43 #include "opto/rootnode.hpp"
44 #include "opto/runtime.hpp"
45 #include "opto/subnode.hpp"
46
47 bool ShenandoahBarrierC2Support::expand(Compile* C, PhaseIterGVN& igvn) {
48 ShenandoahBarrierSetC2State* state = ShenandoahBarrierSetC2::bsc2()->state();
49 if (state->load_reference_barriers_count() > 0) {
50 assert(C->post_loop_opts_phase(), "no loop opts allowed");
51 C->reset_post_loop_opts_phase(); // ... but we know what we are doing
52 C->clear_major_progress();
53 PhaseIdealLoop::optimize(igvn, LoopOptsShenandoahExpand);
54 if (C->failing()) return false;
55
56 C->set_major_progress();
57 if (!C->optimize_loops(igvn, LoopOptsShenandoahPostExpand)) {
58 return false;
59 }
60 C->clear_major_progress();
61 C->process_for_post_loop_opts_igvn(igvn);
62 if (C->failing()) return false;
63
64 C->set_post_loop_opts_phase(); // now for real!
65 }
66 return true;
67 }
68
69 bool ShenandoahBarrierC2Support::is_gc_state_test(Node* iff, int mask) {
70 if (!UseShenandoahGC) {
71 return false;
72 }
73 assert(iff->is_If(), "bad input");
74 if (iff->Opcode() != Op_If) {
75 return false;
76 }
77 Node* bol = iff->in(1);
78 if (!bol->is_Bool() || bol->as_Bool()->_test._test != BoolTest::ne) {
79 return false;
80 }
81 Node* cmp = bol->in(1);
82 if (cmp->Opcode() != Op_CmpI) {
83 return false;
84 }
85 Node* in1 = cmp->in(1);
86 Node* in2 = cmp->in(2);
87 if (in2->find_int_con(-1) != 0) {
88 return false;
89 }
90 if (in1->Opcode() != Op_AndI) {
91 return false;
92 }
93 in2 = in1->in(2);
94 if (in2->find_int_con(-1) != mask) {
95 return false;
96 }
97 in1 = in1->in(1);
98
99 return is_gc_state_load(in1);
100 }
101
102 bool ShenandoahBarrierC2Support::is_heap_stable_test(Node* iff) {
103 return is_gc_state_test(iff, ShenandoahHeap::HAS_FORWARDED);
104 }
105
106 bool ShenandoahBarrierC2Support::is_gc_state_load(Node *n) {
107 if (!UseShenandoahGC) {
108 return false;
109 }
110 if (n->Opcode() != Op_LoadB && n->Opcode() != Op_LoadUB) {
111 return false;
112 }
113 Node* addp = n->in(MemNode::Address);
114 if (!addp->is_AddP()) {
115 return false;
116 }
117 Node* base = addp->in(AddPNode::Address);
118 Node* off = addp->in(AddPNode::Offset);
119 if (base->Opcode() != Op_ThreadLocal) {
120 return false;
121 }
122 if (off->find_intptr_t_con(-1) != in_bytes(ShenandoahThreadLocalData::gc_state_offset())) {
123 return false;
124 }
125 return true;
126 }
127
128 bool ShenandoahBarrierC2Support::has_safepoint_between(Node* start, Node* stop, PhaseIdealLoop *phase) {
129 assert(phase->is_dominator(stop, start), "bad inputs");
130 ResourceMark rm;
131 Unique_Node_List wq;
132 wq.push(start);
133 for (uint next = 0; next < wq.size(); next++) {
134 Node *m = wq.at(next);
135 if (m == stop) {
136 continue;
137 }
138 if (m->is_SafePoint() && !m->is_CallLeaf()) {
139 return true;
140 }
141 if (m->is_Region()) {
142 for (uint i = 1; i < m->req(); i++) {
143 wq.push(m->in(i));
144 }
145 } else {
146 wq.push(m->in(0));
147 }
148 }
149 return false;
150 }
151
152 #ifdef ASSERT
153 bool ShenandoahBarrierC2Support::verify_helper(Node* in, Node_Stack& phis, VectorSet& visited, verify_type t, bool trace, Unique_Node_List& barriers_used) {
154 assert(phis.size() == 0, "");
155
156 while (true) {
157 if (in->bottom_type() == TypePtr::NULL_PTR) {
158 if (trace) {tty->print_cr("null");}
159 } else if (!in->bottom_type()->make_ptr()->make_oopptr()) {
160 if (trace) {tty->print_cr("Non oop");}
161 } else {
162 if (in->is_ConstraintCast()) {
163 in = in->in(1);
164 continue;
165 } else if (in->is_AddP()) {
166 assert(!in->in(AddPNode::Address)->is_top(), "no raw memory access");
167 in = in->in(AddPNode::Address);
168 continue;
169 } else if (in->is_Con()) {
170 if (trace) {
171 tty->print("Found constant");
172 in->dump();
173 }
174 } else if (in->Opcode() == Op_Parm) {
175 if (trace) {
176 tty->print("Found argument");
177 }
178 } else if (in->Opcode() == Op_CreateEx) {
179 if (trace) {
180 tty->print("Found create-exception");
181 }
182 } else if (in->Opcode() == Op_LoadP && in->adr_type() == TypeRawPtr::BOTTOM) {
183 if (trace) {
184 tty->print("Found raw LoadP (OSR argument?)");
185 }
186 } else if (in->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
187 if (t == ShenandoahOopStore) {
188 return false;
189 }
190 barriers_used.push(in);
191 if (trace) {tty->print("Found barrier"); in->dump();}
192 } else if (in->is_Proj() && in->in(0)->is_Allocate()) {
193 if (trace) {
194 tty->print("Found alloc");
195 in->in(0)->dump();
196 }
197 } else if (in->is_Proj() && (in->in(0)->Opcode() == Op_CallStaticJava || in->in(0)->Opcode() == Op_CallDynamicJava)) {
198 if (trace) {
199 tty->print("Found Java call");
200 }
201 } else if (in->is_Phi()) {
202 if (!visited.test_set(in->_idx)) {
203 if (trace) {tty->print("Pushed phi:"); in->dump();}
204 phis.push(in, 2);
205 in = in->in(1);
206 continue;
207 }
208 if (trace) {tty->print("Already seen phi:"); in->dump();}
209 } else if (in->Opcode() == Op_CMoveP || in->Opcode() == Op_CMoveN) {
210 if (!visited.test_set(in->_idx)) {
211 if (trace) {tty->print("Pushed cmovep:"); in->dump();}
212 phis.push(in, CMoveNode::IfTrue);
213 in = in->in(CMoveNode::IfFalse);
214 continue;
215 }
216 if (trace) {tty->print("Already seen cmovep:"); in->dump();}
217 } else if (in->Opcode() == Op_EncodeP || in->Opcode() == Op_DecodeN) {
218 in = in->in(1);
219 continue;
220 } else {
221 return false;
222 }
223 }
224 bool cont = false;
225 while (phis.is_nonempty()) {
226 uint idx = phis.index();
227 Node* phi = phis.node();
228 if (idx >= phi->req()) {
229 if (trace) {tty->print("Popped phi:"); phi->dump();}
230 phis.pop();
231 continue;
232 }
233 if (trace) {tty->print("Next entry(%d) for phi:", idx); phi->dump();}
234 in = phi->in(idx);
235 phis.set_index(idx+1);
236 cont = true;
237 break;
238 }
239 if (!cont) {
240 break;
241 }
242 }
243 return true;
244 }
245
246 void ShenandoahBarrierC2Support::report_verify_failure(const char* msg, Node* n1, Node* n2) {
247 if (n1 != nullptr) {
248 n1->dump(+10);
249 }
250 if (n2 != nullptr) {
251 n2->dump(+10);
252 }
253 fatal("%s", msg);
254 }
255
256 void ShenandoahBarrierC2Support::verify(RootNode* root) {
257 ResourceMark rm;
258 Unique_Node_List wq;
259 GrowableArray<Node*> barriers;
260 Unique_Node_List barriers_used;
261 Node_Stack phis(0);
262 VectorSet visited;
263 const bool trace = false;
264 const bool verify_no_useless_barrier = false;
265
266 wq.push(root);
267 for (uint next = 0; next < wq.size(); next++) {
268 Node *n = wq.at(next);
269 if (n->is_Load()) {
270 const bool trace = false;
271 if (trace) {tty->print("Verifying"); n->dump();}
272 if (n->Opcode() == Op_LoadRange || n->Opcode() == Op_LoadKlass || n->Opcode() == Op_LoadNKlass) {
273 if (trace) {tty->print_cr("Load range/klass");}
274 } else {
275 const TypePtr* adr_type = n->as_Load()->adr_type();
276
277 if (adr_type->isa_oopptr() && adr_type->is_oopptr()->offset() == oopDesc::mark_offset_in_bytes()) {
278 if (trace) {tty->print_cr("Mark load");}
279 } else if (adr_type->isa_instptr() &&
280 adr_type->is_instptr()->instance_klass()->is_subtype_of(Compile::current()->env()->Reference_klass()) &&
281 adr_type->is_instptr()->offset() == java_lang_ref_Reference::referent_offset()) {
282 if (trace) {tty->print_cr("Reference.get()");}
283 } else if (!verify_helper(n->in(MemNode::Address), phis, visited, ShenandoahLoad, trace, barriers_used)) {
284 report_verify_failure("Shenandoah verification: Load should have barriers", n);
285 }
286 }
287 } else if (n->is_Store()) {
288 const bool trace = false;
289
290 if (trace) {tty->print("Verifying"); n->dump();}
291 if (n->in(MemNode::ValueIn)->bottom_type()->make_oopptr()) {
292 Node* adr = n->in(MemNode::Address);
293 bool verify = true;
294
295 if (adr->is_AddP() && adr->in(AddPNode::Base)->is_top()) {
296 adr = adr->in(AddPNode::Address);
297 if (adr->is_AddP()) {
298 assert(adr->in(AddPNode::Base)->is_top(), "");
299 adr = adr->in(AddPNode::Address);
300 if (adr->Opcode() == Op_LoadP &&
301 adr->in(MemNode::Address)->in(AddPNode::Base)->is_top() &&
302 adr->in(MemNode::Address)->in(AddPNode::Address)->Opcode() == Op_ThreadLocal &&
303 adr->in(MemNode::Address)->in(AddPNode::Offset)->find_intptr_t_con(-1) == in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset())) {
304 if (trace) {tty->print_cr("SATB prebarrier");}
305 verify = false;
306 }
307 }
308 }
309
310 if (verify && !verify_helper(n->in(MemNode::ValueIn), phis, visited, ShenandoahValue, trace, barriers_used)) {
311 report_verify_failure("Shenandoah verification: Store should have barriers", n);
312 }
313 }
314 if (!verify_helper(n->in(MemNode::Address), phis, visited, ShenandoahStore, trace, barriers_used)) {
315 report_verify_failure("Shenandoah verification: Store (address) should have barriers", n);
316 }
317 } else if (n->Opcode() == Op_CmpP) {
318 const bool trace = false;
319
320 Node* in1 = n->in(1);
321 Node* in2 = n->in(2);
322 if (in1->bottom_type()->isa_oopptr()) {
323 if (trace) {tty->print("Verifying"); n->dump();}
324
325 bool mark_inputs = false;
326 if (in1->bottom_type() == TypePtr::NULL_PTR || in2->bottom_type() == TypePtr::NULL_PTR ||
327 (in1->is_Con() || in2->is_Con())) {
328 if (trace) {tty->print_cr("Comparison against a constant");}
329 mark_inputs = true;
330 } else if ((in1->is_CheckCastPP() && in1->in(1)->is_Proj() && in1->in(1)->in(0)->is_Allocate()) ||
331 (in2->is_CheckCastPP() && in2->in(1)->is_Proj() && in2->in(1)->in(0)->is_Allocate())) {
332 if (trace) {tty->print_cr("Comparison with newly alloc'ed object");}
333 mark_inputs = true;
334 } else {
335 assert(in2->bottom_type()->isa_oopptr(), "");
336
337 if (!verify_helper(in1, phis, visited, ShenandoahStore, trace, barriers_used) ||
338 !verify_helper(in2, phis, visited, ShenandoahStore, trace, barriers_used)) {
339 report_verify_failure("Shenandoah verification: Cmp should have barriers", n);
340 }
341 }
342 if (verify_no_useless_barrier &&
343 mark_inputs &&
344 (!verify_helper(in1, phis, visited, ShenandoahValue, trace, barriers_used) ||
345 !verify_helper(in2, phis, visited, ShenandoahValue, trace, barriers_used))) {
346 phis.clear();
347 visited.reset();
348 }
349 }
350 } else if (n->is_LoadStore()) {
351 if (n->in(MemNode::ValueIn)->bottom_type()->make_ptr() &&
352 !verify_helper(n->in(MemNode::ValueIn), phis, visited, ShenandoahValue, trace, barriers_used)) {
353 report_verify_failure("Shenandoah verification: LoadStore (value) should have barriers", n);
354 }
355
356 if (n->in(MemNode::Address)->bottom_type()->make_oopptr() && !verify_helper(n->in(MemNode::Address), phis, visited, ShenandoahStore, trace, barriers_used)) {
357 report_verify_failure("Shenandoah verification: LoadStore (address) should have barriers", n);
358 }
359 } else if (n->Opcode() == Op_CallLeafNoFP || n->Opcode() == Op_CallLeaf) {
360 CallNode* call = n->as_Call();
361
362 static struct {
363 const char* name;
364 struct {
365 int pos;
366 verify_type t;
367 } args[6];
368 } calls[] = {
369 "array_partition_stub",
370 { { TypeFunc::Parms, ShenandoahStore }, { TypeFunc::Parms+4, ShenandoahStore }, { -1, ShenandoahNone },
371 { -1, ShenandoahNone }, { -1, ShenandoahNone }, { -1, ShenandoahNone } },
372 "arraysort_stub",
373 { { TypeFunc::Parms, ShenandoahStore }, { -1, ShenandoahNone }, { -1, ShenandoahNone },
374 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
375 "aescrypt_encryptBlock",
376 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad },
377 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
378 "aescrypt_decryptBlock",
379 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad },
380 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
381 "multiplyToLen",
382 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+2, ShenandoahLoad }, { TypeFunc::Parms+4, ShenandoahStore },
383 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
384 "squareToLen",
385 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+2, ShenandoahLoad }, { -1, ShenandoahNone},
386 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
387 "montgomery_multiply",
388 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahLoad }, { TypeFunc::Parms+2, ShenandoahLoad },
389 { TypeFunc::Parms+6, ShenandoahStore }, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
390 "montgomery_square",
391 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahLoad }, { TypeFunc::Parms+5, ShenandoahStore },
392 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
393 "mulAdd",
394 { { TypeFunc::Parms, ShenandoahStore }, { TypeFunc::Parms+1, ShenandoahLoad }, { -1, ShenandoahNone},
395 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
396 "vectorizedMismatch",
397 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahLoad }, { -1, ShenandoahNone},
398 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
399 "updateBytesCRC32",
400 { { TypeFunc::Parms+1, ShenandoahLoad }, { -1, ShenandoahNone}, { -1, ShenandoahNone},
401 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
402 "updateBytesAdler32",
403 { { TypeFunc::Parms+1, ShenandoahLoad }, { -1, ShenandoahNone}, { -1, ShenandoahNone},
404 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
405 "updateBytesCRC32C",
406 { { TypeFunc::Parms+1, ShenandoahLoad }, { TypeFunc::Parms+3, ShenandoahLoad}, { -1, ShenandoahNone},
407 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
408 "counterMode_AESCrypt",
409 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad },
410 { TypeFunc::Parms+3, ShenandoahStore }, { TypeFunc::Parms+5, ShenandoahStore }, { TypeFunc::Parms+6, ShenandoahStore } },
411 "cipherBlockChaining_encryptAESCrypt",
412 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad },
413 { TypeFunc::Parms+3, ShenandoahLoad }, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
414 "cipherBlockChaining_decryptAESCrypt",
415 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad },
416 { TypeFunc::Parms+3, ShenandoahLoad }, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
417 "shenandoah_clone",
418 { { TypeFunc::Parms, ShenandoahLoad }, { -1, ShenandoahNone}, { -1, ShenandoahNone},
419 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
420 "ghash_processBlocks",
421 { { TypeFunc::Parms, ShenandoahStore }, { TypeFunc::Parms+1, ShenandoahLoad }, { TypeFunc::Parms+2, ShenandoahLoad },
422 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
423 "sha1_implCompress",
424 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
425 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
426 "sha256_implCompress",
427 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
428 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
429 "sha512_implCompress",
430 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
431 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
432 "sha1_implCompressMB",
433 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
434 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
435 "sha256_implCompressMB",
436 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
437 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
438 "sha512_implCompressMB",
439 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahStore }, { -1, ShenandoahNone },
440 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
441 "encodeBlock",
442 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+3, ShenandoahStore }, { -1, ShenandoahNone },
443 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
444 "decodeBlock",
445 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+3, ShenandoahStore }, { -1, ShenandoahNone },
446 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
447 "intpoly_montgomeryMult_P256",
448 { { TypeFunc::Parms, ShenandoahLoad }, { TypeFunc::Parms+1, ShenandoahLoad }, { TypeFunc::Parms+2, ShenandoahStore },
449 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
450 "intpoly_assign",
451 { { TypeFunc::Parms+1, ShenandoahStore }, { TypeFunc::Parms+2, ShenandoahLoad }, { -1, ShenandoahNone },
452 { -1, ShenandoahNone}, { -1, ShenandoahNone}, { -1, ShenandoahNone} },
453 };
454
455 if (call->is_call_to_arraycopystub()) {
456 Node* dest = nullptr;
457 const TypeTuple* args = n->as_Call()->_tf->domain();
458 for (uint i = TypeFunc::Parms, j = 0; i < args->cnt(); i++) {
459 if (args->field_at(i)->isa_ptr()) {
460 j++;
461 if (j == 2) {
462 dest = n->in(i);
463 break;
464 }
465 }
466 }
467 if (!verify_helper(n->in(TypeFunc::Parms), phis, visited, ShenandoahLoad, trace, barriers_used) ||
468 !verify_helper(dest, phis, visited, ShenandoahStore, trace, barriers_used)) {
469 report_verify_failure("Shenandoah verification: ArrayCopy should have barriers", n);
470 }
471 } else if (strlen(call->_name) > 5 &&
472 !strcmp(call->_name + strlen(call->_name) - 5, "_fill")) {
473 if (!verify_helper(n->in(TypeFunc::Parms), phis, visited, ShenandoahStore, trace, barriers_used)) {
474 report_verify_failure("Shenandoah verification: _fill should have barriers", n);
475 }
476 } else if (!strcmp(call->_name, "shenandoah_wb_pre")) {
477 // skip
478 } else {
479 const int calls_len = sizeof(calls) / sizeof(calls[0]);
480 int i = 0;
481 for (; i < calls_len; i++) {
482 if (!strcmp(calls[i].name, call->_name)) {
483 break;
484 }
485 }
486 if (i != calls_len) {
487 const uint args_len = sizeof(calls[0].args) / sizeof(calls[0].args[0]);
488 for (uint j = 0; j < args_len; j++) {
489 int pos = calls[i].args[j].pos;
490 if (pos == -1) {
491 break;
492 }
493 if (!verify_helper(call->in(pos), phis, visited, calls[i].args[j].t, trace, barriers_used)) {
494 report_verify_failure("Shenandoah verification: intrinsic calls should have barriers", n);
495 }
496 }
497 for (uint j = TypeFunc::Parms; j < call->req(); j++) {
498 if (call->in(j)->bottom_type()->make_ptr() &&
499 call->in(j)->bottom_type()->make_ptr()->isa_oopptr()) {
500 uint k = 0;
501 for (; k < args_len && calls[i].args[k].pos != (int)j; k++);
502 if (k == args_len) {
503 fatal("arg %d for call %s not covered", j, call->_name);
504 }
505 }
506 }
507 } else {
508 for (uint j = TypeFunc::Parms; j < call->req(); j++) {
509 if (call->in(j)->bottom_type()->make_ptr() &&
510 call->in(j)->bottom_type()->make_ptr()->isa_oopptr()) {
511 fatal("%s not covered", call->_name);
512 }
513 }
514 }
515 }
516 } else if (n->Opcode() == Op_ShenandoahLoadReferenceBarrier) {
517 // skip
518 } else if (n->is_AddP()
519 || n->is_Phi()
520 || n->is_ConstraintCast()
521 || n->Opcode() == Op_Return
522 || n->Opcode() == Op_CMoveP
523 || n->Opcode() == Op_CMoveN
524 || n->Opcode() == Op_Rethrow
525 || n->is_MemBar()
526 || n->Opcode() == Op_Conv2B
527 || n->Opcode() == Op_SafePoint
528 || n->is_CallJava()
529 || n->Opcode() == Op_Unlock
530 || n->Opcode() == Op_EncodeP
531 || n->Opcode() == Op_DecodeN) {
532 // nothing to do
533 } else {
534 static struct {
535 int opcode;
536 struct {
537 int pos;
538 verify_type t;
539 } inputs[2];
540 } others[] = {
541 Op_FastLock,
542 { { 1, ShenandoahLoad }, { -1, ShenandoahNone} },
543 Op_Lock,
544 { { TypeFunc::Parms, ShenandoahLoad }, { -1, ShenandoahNone} },
545 Op_ArrayCopy,
546 { { ArrayCopyNode::Src, ShenandoahLoad }, { ArrayCopyNode::Dest, ShenandoahStore } },
547 Op_StrCompressedCopy,
548 { { 2, ShenandoahLoad }, { 3, ShenandoahStore } },
549 Op_StrInflatedCopy,
550 { { 2, ShenandoahLoad }, { 3, ShenandoahStore } },
551 Op_AryEq,
552 { { 2, ShenandoahLoad }, { 3, ShenandoahLoad } },
553 Op_StrIndexOf,
554 { { 2, ShenandoahLoad }, { 4, ShenandoahLoad } },
555 Op_StrComp,
556 { { 2, ShenandoahLoad }, { 4, ShenandoahLoad } },
557 Op_StrEquals,
558 { { 2, ShenandoahLoad }, { 3, ShenandoahLoad } },
559 Op_VectorizedHashCode,
560 { { 2, ShenandoahLoad }, { -1, ShenandoahNone } },
561 Op_EncodeISOArray,
562 { { 2, ShenandoahLoad }, { 3, ShenandoahStore } },
563 Op_CountPositives,
564 { { 2, ShenandoahLoad }, { -1, ShenandoahNone} },
565 Op_CastP2X,
566 { { 1, ShenandoahLoad }, { -1, ShenandoahNone} },
567 Op_StrIndexOfChar,
568 { { 2, ShenandoahLoad }, { -1, ShenandoahNone } },
569 };
570
571 const int others_len = sizeof(others) / sizeof(others[0]);
572 int i = 0;
573 for (; i < others_len; i++) {
574 if (others[i].opcode == n->Opcode()) {
575 break;
576 }
577 }
578 uint stop = n->is_Call() ? n->as_Call()->tf()->domain()->cnt() : n->req();
579 if (i != others_len) {
580 const uint inputs_len = sizeof(others[0].inputs) / sizeof(others[0].inputs[0]);
581 for (uint j = 0; j < inputs_len; j++) {
582 int pos = others[i].inputs[j].pos;
583 if (pos == -1) {
584 break;
585 }
586 if (!verify_helper(n->in(pos), phis, visited, others[i].inputs[j].t, trace, barriers_used)) {
587 report_verify_failure("Shenandoah verification: intrinsic calls should have barriers", n);
588 }
589 }
590 for (uint j = 1; j < stop; j++) {
591 if (n->in(j) != nullptr && n->in(j)->bottom_type()->make_ptr() &&
592 n->in(j)->bottom_type()->make_ptr()->make_oopptr()) {
593 uint k = 0;
594 for (; k < inputs_len && others[i].inputs[k].pos != (int)j; k++);
595 if (k == inputs_len) {
596 fatal("arg %d for node %s not covered", j, n->Name());
597 }
598 }
599 }
600 } else {
601 for (uint j = 1; j < stop; j++) {
602 if (n->in(j) != nullptr && n->in(j)->bottom_type()->make_ptr() &&
603 n->in(j)->bottom_type()->make_ptr()->make_oopptr()) {
604 fatal("%s not covered", n->Name());
605 }
606 }
607 }
608 }
609
610 if (n->is_SafePoint()) {
611 SafePointNode* sfpt = n->as_SafePoint();
612 if (verify_no_useless_barrier && sfpt->jvms() != nullptr) {
613 for (uint i = sfpt->jvms()->scloff(); i < sfpt->jvms()->endoff(); i++) {
614 if (!verify_helper(sfpt->in(i), phis, visited, ShenandoahLoad, trace, barriers_used)) {
615 phis.clear();
616 visited.reset();
617 }
618 }
619 }
620 }
621 }
622
623 if (verify_no_useless_barrier) {
624 for (int i = 0; i < barriers.length(); i++) {
625 Node* n = barriers.at(i);
626 if (!barriers_used.member(n)) {
627 tty->print("XXX useless barrier"); n->dump(-2);
628 ShouldNotReachHere();
629 }
630 }
631 }
632 }
633 #endif
634
635 bool ShenandoahBarrierC2Support::is_dominator_same_ctrl(Node* c, Node* d, Node* n, PhaseIdealLoop* phase) {
636 // That both nodes have the same control is not sufficient to prove
637 // domination, verify that there's no path from d to n
638 ResourceMark rm;
639 Unique_Node_List wq;
640 wq.push(d);
641 for (uint next = 0; next < wq.size(); next++) {
642 Node *m = wq.at(next);
643 if (m == n) {
644 return false;
645 }
646 if (m->is_Phi() && m->in(0)->is_Loop()) {
647 assert(phase->ctrl_or_self(m->in(LoopNode::EntryControl)) != c, "following loop entry should lead to new control");
648 } else {
649 if (m->is_Store() || m->is_LoadStore()) {
650 // Take anti-dependencies into account
651 Node* mem = m->in(MemNode::Memory);
652 for (DUIterator_Fast imax, i = mem->fast_outs(imax); i < imax; i++) {
653 Node* u = mem->fast_out(i);
654 if (u->is_Load() && phase->C->can_alias(m->adr_type(), phase->C->get_alias_index(u->adr_type())) &&
655 phase->ctrl_or_self(u) == c) {
656 wq.push(u);
657 }
658 }
659 }
660 for (uint i = 0; i < m->req(); i++) {
661 if (m->in(i) != nullptr && phase->ctrl_or_self(m->in(i)) == c) {
662 wq.push(m->in(i));
663 }
664 }
665 }
666 }
667 return true;
668 }
669
670 bool ShenandoahBarrierC2Support::is_dominator(Node* d_c, Node* n_c, Node* d, Node* n, PhaseIdealLoop* phase) {
671 if (d_c != n_c) {
672 return phase->is_dominator(d_c, n_c);
673 }
674 return is_dominator_same_ctrl(d_c, d, n, phase);
675 }
676
677 Node* next_mem(Node* mem, int alias) {
678 Node* res = nullptr;
679 if (mem->is_Proj()) {
680 res = mem->in(0);
681 } else if (mem->is_SafePoint() || mem->is_MemBar()) {
682 res = mem->in(TypeFunc::Memory);
683 } else if (mem->is_Phi()) {
684 res = mem->in(1);
685 } else if (mem->is_MergeMem()) {
686 res = mem->as_MergeMem()->memory_at(alias);
687 } else if (mem->is_Store() || mem->is_LoadStore() || mem->is_ClearArray()) {
688 assert(alias == Compile::AliasIdxRaw, "following raw memory can't lead to a barrier");
689 res = mem->in(MemNode::Memory);
690 } else {
691 #ifdef ASSERT
692 mem->dump();
693 #endif
694 ShouldNotReachHere();
695 }
696 return res;
697 }
698
699 Node* ShenandoahBarrierC2Support::no_branches(Node* c, Node* dom, bool allow_one_proj, PhaseIdealLoop* phase) {
700 Node* iffproj = nullptr;
701 while (c != dom) {
702 Node* next = phase->idom(c);
703 assert(next->unique_ctrl_out_or_null() == c || c->is_Proj() || c->is_Region(), "multiple control flow out but no proj or region?");
704 if (c->is_Region()) {
705 ResourceMark rm;
706 Unique_Node_List wq;
707 wq.push(c);
708 for (uint i = 0; i < wq.size(); i++) {
709 Node *n = wq.at(i);
710 if (n == next) {
711 continue;
712 }
713 if (n->is_Region()) {
714 for (uint j = 1; j < n->req(); j++) {
715 wq.push(n->in(j));
716 }
717 } else {
718 wq.push(n->in(0));
719 }
720 }
721 for (uint i = 0; i < wq.size(); i++) {
722 Node *n = wq.at(i);
723 assert(n->is_CFG(), "");
724 if (n->is_Multi()) {
725 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++) {
726 Node* u = n->fast_out(j);
727 if (u->is_CFG()) {
728 if (!wq.member(u) && !u->as_Proj()->is_uncommon_trap_proj()) {
729 return NodeSentinel;
730 }
731 }
732 }
733 }
734 }
735 } else if (c->is_Proj()) {
736 if (c->is_IfProj()) {
737 if (c->as_Proj()->is_uncommon_trap_if_pattern() != nullptr) {
738 // continue;
739 } else {
740 if (!allow_one_proj) {
741 return NodeSentinel;
742 }
743 if (iffproj == nullptr) {
744 iffproj = c;
745 } else {
746 return NodeSentinel;
747 }
748 }
749 } else if (c->Opcode() == Op_JumpProj) {
750 return NodeSentinel; // unsupported
751 } else if (c->Opcode() == Op_CatchProj) {
752 return NodeSentinel; // unsupported
753 } else if (c->Opcode() == Op_CProj && next->is_NeverBranch()) {
754 return NodeSentinel; // unsupported
755 } else {
756 assert(next->unique_ctrl_out() == c, "unsupported branch pattern");
757 }
758 }
759 c = next;
760 }
761 return iffproj;
762 }
763
764 Node* ShenandoahBarrierC2Support::dom_mem(Node* mem, Node* ctrl, int alias, Node*& mem_ctrl, PhaseIdealLoop* phase) {
765 ResourceMark rm;
766 VectorSet wq;
767 wq.set(mem->_idx);
768 mem_ctrl = phase->ctrl_or_self(mem);
769 while (!phase->is_dominator(mem_ctrl, ctrl) || mem_ctrl == ctrl) {
770 mem = next_mem(mem, alias);
771 if (wq.test_set(mem->_idx)) {
772 return nullptr;
773 }
774 mem_ctrl = phase->ctrl_or_self(mem);
775 }
776 if (mem->is_MergeMem()) {
777 mem = mem->as_MergeMem()->memory_at(alias);
778 mem_ctrl = phase->ctrl_or_self(mem);
779 }
780 return mem;
781 }
782
783 Node* ShenandoahBarrierC2Support::find_bottom_mem(Node* ctrl, PhaseIdealLoop* phase) {
784 Node* mem = nullptr;
785 Node* c = ctrl;
786 do {
787 if (c->is_Region()) {
788 for (DUIterator_Fast imax, i = c->fast_outs(imax); i < imax && mem == nullptr; i++) {
789 Node* u = c->fast_out(i);
790 if (u->is_Phi() && u->bottom_type() == Type::MEMORY) {
791 if (u->adr_type() == TypePtr::BOTTOM) {
792 mem = u;
793 }
794 }
795 }
796 } else {
797 if (c->is_Call() && c->as_Call()->adr_type() != nullptr) {
798 CallProjections projs;
799 c->as_Call()->extract_projections(&projs, true, false);
800 if (projs.fallthrough_memproj != nullptr) {
801 if (projs.fallthrough_memproj->adr_type() == TypePtr::BOTTOM) {
802 if (projs.catchall_memproj == nullptr) {
803 mem = projs.fallthrough_memproj;
804 } else {
805 if (phase->is_dominator(projs.fallthrough_catchproj, ctrl)) {
806 mem = projs.fallthrough_memproj;
807 } else {
808 assert(phase->is_dominator(projs.catchall_catchproj, ctrl), "one proj must dominate barrier");
809 mem = projs.catchall_memproj;
810 }
811 }
812 }
813 } else {
814 Node* proj = c->as_Call()->proj_out(TypeFunc::Memory);
815 if (proj != nullptr &&
816 proj->adr_type() == TypePtr::BOTTOM) {
817 mem = proj;
818 }
819 }
820 } else {
821 for (DUIterator_Fast imax, i = c->fast_outs(imax); i < imax; i++) {
822 Node* u = c->fast_out(i);
823 if (u->is_Proj() &&
824 u->bottom_type() == Type::MEMORY &&
825 u->adr_type() == TypePtr::BOTTOM) {
826 assert(c->is_SafePoint() || c->is_MemBar() || c->is_Start(), "");
827 assert(mem == nullptr, "only one proj");
828 mem = u;
829 }
830 }
831 assert(!c->is_Call() || c->as_Call()->adr_type() != nullptr || mem == nullptr, "no mem projection expected");
832 }
833 }
834 c = phase->idom(c);
835 } while (mem == nullptr);
836 return mem;
837 }
838
839 void ShenandoahBarrierC2Support::follow_barrier_uses(Node* n, Node* ctrl, Unique_Node_List& uses, PhaseIdealLoop* phase) {
840 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
841 Node* u = n->fast_out(i);
842 if (!u->is_CFG() && phase->get_ctrl(u) == ctrl && (!u->is_Phi() || !u->in(0)->is_Loop() || u->in(LoopNode::LoopBackControl) != n)) {
843 uses.push(u);
844 }
845 }
846 }
847
848 static void hide_strip_mined_loop(OuterStripMinedLoopNode* outer, CountedLoopNode* inner, PhaseIdealLoop* phase) {
849 OuterStripMinedLoopEndNode* le = inner->outer_loop_end();
850 Node* new_outer = new LoopNode(outer->in(LoopNode::EntryControl), outer->in(LoopNode::LoopBackControl));
851 phase->register_control(new_outer, phase->get_loop(outer), outer->in(LoopNode::EntryControl));
852 Node* new_le = new IfNode(le->in(0), le->in(1), le->_prob, le->_fcnt);
853 phase->register_control(new_le, phase->get_loop(le), le->in(0));
854 phase->lazy_replace(outer, new_outer);
855 phase->lazy_replace(le, new_le);
856 inner->clear_strip_mined();
857 }
858
859 void ShenandoahBarrierC2Support::test_gc_state(Node*& ctrl, Node* raw_mem, Node*& test_fail_ctrl,
860 PhaseIdealLoop* phase, int flags) {
861 PhaseIterGVN& igvn = phase->igvn();
862 Node* old_ctrl = ctrl;
863
864 Node* thread = new ThreadLocalNode();
865 Node* gc_state_offset = igvn.MakeConX(in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
866 Node* gc_state_addr = new AddPNode(phase->C->top(), thread, gc_state_offset);
867 Node* gc_state = new LoadBNode(old_ctrl, raw_mem, gc_state_addr,
868 DEBUG_ONLY(phase->C->get_adr_type(Compile::AliasIdxRaw)) NOT_DEBUG(nullptr),
869 TypeInt::BYTE, MemNode::unordered);
870 Node* gc_state_and = new AndINode(gc_state, igvn.intcon(flags));
871 Node* gc_state_cmp = new CmpINode(gc_state_and, igvn.zerocon(T_INT));
872 Node* gc_state_bool = new BoolNode(gc_state_cmp, BoolTest::ne);
873
874 IfNode* gc_state_iff = new IfNode(old_ctrl, gc_state_bool, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
875 ctrl = new IfTrueNode(gc_state_iff);
876 test_fail_ctrl = new IfFalseNode(gc_state_iff);
877
878 IdealLoopTree* loop = phase->get_loop(old_ctrl);
879 phase->register_control(gc_state_iff, loop, old_ctrl);
880 phase->register_control(ctrl, loop, gc_state_iff);
881 phase->register_control(test_fail_ctrl, loop, gc_state_iff);
882
883 phase->register_new_node(thread, old_ctrl);
884 phase->register_new_node(gc_state_addr, old_ctrl);
885 phase->register_new_node(gc_state, old_ctrl);
886 phase->register_new_node(gc_state_and, old_ctrl);
887 phase->register_new_node(gc_state_cmp, old_ctrl);
888 phase->register_new_node(gc_state_bool, old_ctrl);
889
890 phase->set_ctrl(gc_state_offset, phase->C->root());
891
892 assert(is_gc_state_test(gc_state_iff, flags), "Should match the shape");
893 }
894
895 void ShenandoahBarrierC2Support::test_null(Node*& ctrl, Node* val, Node*& null_ctrl, PhaseIdealLoop* phase) {
896 Node* old_ctrl = ctrl;
897 PhaseIterGVN& igvn = phase->igvn();
898
899 const Type* val_t = igvn.type(val);
900 if (val_t->meet(TypePtr::NULL_PTR) == val_t) {
901 Node* null_cmp = new CmpPNode(val, igvn.zerocon(T_OBJECT));
902 Node* null_test = new BoolNode(null_cmp, BoolTest::ne);
903
904 IfNode* null_iff = new IfNode(old_ctrl, null_test, PROB_LIKELY(0.999), COUNT_UNKNOWN);
905 ctrl = new IfTrueNode(null_iff);
906 null_ctrl = new IfFalseNode(null_iff);
907
908 IdealLoopTree* loop = phase->get_loop(old_ctrl);
909 phase->register_control(null_iff, loop, old_ctrl);
910 phase->register_control(ctrl, loop, null_iff);
911 phase->register_control(null_ctrl, loop, null_iff);
912
913 phase->register_new_node(null_cmp, old_ctrl);
914 phase->register_new_node(null_test, old_ctrl);
915 }
916 }
917
918 void ShenandoahBarrierC2Support::test_in_cset(Node*& ctrl, Node*& not_cset_ctrl, Node* val, Node* raw_mem, PhaseIdealLoop* phase) {
919 Node* old_ctrl = ctrl;
920 PhaseIterGVN& igvn = phase->igvn();
921
922 Node* raw_val = new CastP2XNode(old_ctrl, val);
923 Node* cset_idx = new URShiftXNode(raw_val, igvn.intcon(ShenandoahHeapRegion::region_size_bytes_shift_jint()));
924
925 // Figure out the target cset address with raw pointer math.
926 // This avoids matching AddP+LoadB that would emit inefficient code.
927 // See JDK-8245465.
928 Node* cset_addr_ptr = igvn.makecon(TypeRawPtr::make(ShenandoahHeap::in_cset_fast_test_addr()));
929 Node* cset_addr = new CastP2XNode(old_ctrl, cset_addr_ptr);
930 Node* cset_load_addr = new AddXNode(cset_addr, cset_idx);
931 Node* cset_load_ptr = new CastX2PNode(cset_load_addr);
932
933 Node* cset_load = new LoadBNode(old_ctrl, raw_mem, cset_load_ptr,
934 DEBUG_ONLY(phase->C->get_adr_type(Compile::AliasIdxRaw)) NOT_DEBUG(nullptr),
935 TypeInt::BYTE, MemNode::unordered);
936 Node* cset_cmp = new CmpINode(cset_load, igvn.zerocon(T_INT));
937 Node* cset_bool = new BoolNode(cset_cmp, BoolTest::ne);
938
939 IfNode* cset_iff = new IfNode(old_ctrl, cset_bool, PROB_UNLIKELY(0.999), COUNT_UNKNOWN);
940 ctrl = new IfTrueNode(cset_iff);
941 not_cset_ctrl = new IfFalseNode(cset_iff);
942
943 IdealLoopTree *loop = phase->get_loop(old_ctrl);
944 phase->register_control(cset_iff, loop, old_ctrl);
945 phase->register_control(ctrl, loop, cset_iff);
946 phase->register_control(not_cset_ctrl, loop, cset_iff);
947
948 phase->set_ctrl(cset_addr_ptr, phase->C->root());
949
950 phase->register_new_node(raw_val, old_ctrl);
951 phase->register_new_node(cset_idx, old_ctrl);
952 phase->register_new_node(cset_addr, old_ctrl);
953 phase->register_new_node(cset_load_addr, old_ctrl);
954 phase->register_new_node(cset_load_ptr, old_ctrl);
955 phase->register_new_node(cset_load, old_ctrl);
956 phase->register_new_node(cset_cmp, old_ctrl);
957 phase->register_new_node(cset_bool, old_ctrl);
958 }
959
960 void ShenandoahBarrierC2Support::call_lrb_stub(Node*& ctrl, Node*& val, Node* load_addr,
961 DecoratorSet decorators, PhaseIdealLoop* phase) {
962 IdealLoopTree*loop = phase->get_loop(ctrl);
963 const TypePtr* obj_type = phase->igvn().type(val)->is_oopptr();
964
965 address calladdr = nullptr;
966 const char* name = nullptr;
967 bool is_strong = ShenandoahBarrierSet::is_strong_access(decorators);
968 bool is_weak = ShenandoahBarrierSet::is_weak_access(decorators);
969 bool is_phantom = ShenandoahBarrierSet::is_phantom_access(decorators);
970 bool is_native = ShenandoahBarrierSet::is_native_access(decorators);
971 bool is_narrow = UseCompressedOops && !is_native;
972 if (is_strong) {
973 if (is_narrow) {
974 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong_narrow);
975 name = "load_reference_barrier_strong_narrow";
976 } else {
977 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_strong);
978 name = "load_reference_barrier_strong";
979 }
980 } else if (is_weak) {
981 if (is_narrow) {
982 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak_narrow);
983 name = "load_reference_barrier_weak_narrow";
984 } else {
985 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_weak);
986 name = "load_reference_barrier_weak";
987 }
988 } else {
989 assert(is_phantom, "only remaining strength");
990 if (is_narrow) {
991 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom_narrow);
992 name = "load_reference_barrier_phantom_narrow";
993 } else {
994 calladdr = CAST_FROM_FN_PTR(address, ShenandoahRuntime::load_reference_barrier_phantom);
995 name = "load_reference_barrier_phantom";
996 }
997 }
998 Node* call = new CallLeafNode(ShenandoahBarrierSetC2::load_reference_barrier_Type(), calladdr, name, TypeRawPtr::BOTTOM);
999
1000 call->init_req(TypeFunc::Control, ctrl);
1001 call->init_req(TypeFunc::I_O, phase->C->top());
1002 call->init_req(TypeFunc::Memory, phase->C->top());
1003 call->init_req(TypeFunc::FramePtr, phase->C->top());
1004 call->init_req(TypeFunc::ReturnAdr, phase->C->top());
1005 call->init_req(TypeFunc::Parms, val);
1006 call->init_req(TypeFunc::Parms+1, load_addr);
1007 phase->register_control(call, loop, ctrl);
1008 ctrl = new ProjNode(call, TypeFunc::Control);
1009 phase->register_control(ctrl, loop, call);
1010 val = new ProjNode(call, TypeFunc::Parms);
1011 phase->register_new_node(val, call);
1012 val = new CheckCastPPNode(ctrl, val, obj_type);
1013 phase->register_new_node(val, ctrl);
1014 }
1015
1016 void ShenandoahBarrierC2Support::fix_ctrl(Node* barrier, Node* region, const MemoryGraphFixer& fixer, Unique_Node_List& uses, Unique_Node_List& uses_to_ignore, uint last, PhaseIdealLoop* phase) {
1017 Node* ctrl = phase->get_ctrl(barrier);
1018 Node* init_raw_mem = fixer.find_mem(ctrl, barrier);
1019
1020 // Update the control of all nodes that should be after the
1021 // barrier control flow
1022 uses.clear();
1023 // Every node that is control dependent on the barrier's input
1024 // control will be after the expanded barrier. The raw memory (if
1025 // its memory is control dependent on the barrier's input control)
1026 // must stay above the barrier.
1027 uses_to_ignore.clear();
1028 if (phase->has_ctrl(init_raw_mem) && phase->get_ctrl(init_raw_mem) == ctrl && !init_raw_mem->is_Phi()) {
1029 uses_to_ignore.push(init_raw_mem);
1030 }
1031 for (uint next = 0; next < uses_to_ignore.size(); next++) {
1032 Node *n = uses_to_ignore.at(next);
1033 for (uint i = 0; i < n->req(); i++) {
1034 Node* in = n->in(i);
1035 if (in != nullptr && phase->has_ctrl(in) && phase->get_ctrl(in) == ctrl) {
1036 uses_to_ignore.push(in);
1037 }
1038 }
1039 }
1040 for (DUIterator_Fast imax, i = ctrl->fast_outs(imax); i < imax; i++) {
1041 Node* u = ctrl->fast_out(i);
1042 if (u->_idx < last &&
1043 u != barrier &&
1044 !u->depends_only_on_test() && // preserve dependency on test
1045 !uses_to_ignore.member(u) &&
1046 (u->in(0) != ctrl || (!u->is_Region() && !u->is_Phi())) &&
1047 (ctrl->Opcode() != Op_CatchProj || u->Opcode() != Op_CreateEx)) {
1048 Node* old_c = phase->ctrl_or_self(u);
1049 Node* c = old_c;
1050 if (c != ctrl ||
1051 is_dominator_same_ctrl(old_c, barrier, u, phase) ||
1052 ShenandoahBarrierSetC2::is_shenandoah_state_load(u)) {
1053 phase->igvn().rehash_node_delayed(u);
1054 int nb = u->replace_edge(ctrl, region, &phase->igvn());
1055 if (u->is_CFG()) {
1056 if (phase->idom(u) == ctrl) {
1057 phase->set_idom(u, region, phase->dom_depth(region));
1058 }
1059 } else if (phase->get_ctrl(u) == ctrl) {
1060 assert(u != init_raw_mem, "should leave input raw mem above the barrier");
1061 uses.push(u);
1062 }
1063 assert(nb == 1, "more than 1 ctrl input?");
1064 --i, imax -= nb;
1065 }
1066 }
1067 }
1068 }
1069
1070 static Node* create_phis_on_call_return(Node* ctrl, Node* c, Node* n, Node* n_clone, const CallProjections& projs, PhaseIdealLoop* phase) {
1071 Node* region = nullptr;
1072 while (c != ctrl) {
1073 if (c->is_Region()) {
1074 region = c;
1075 }
1076 c = phase->idom(c);
1077 }
1078 assert(region != nullptr, "");
1079 Node* phi = new PhiNode(region, n->bottom_type());
1080 for (uint j = 1; j < region->req(); j++) {
1081 Node* in = region->in(j);
1082 if (phase->is_dominator(projs.fallthrough_catchproj, in)) {
1083 phi->init_req(j, n);
1084 } else if (phase->is_dominator(projs.catchall_catchproj, in)) {
1085 phi->init_req(j, n_clone);
1086 } else {
1087 phi->init_req(j, create_phis_on_call_return(ctrl, in, n, n_clone, projs, phase));
1088 }
1089 }
1090 phase->register_new_node(phi, region);
1091 return phi;
1092 }
1093
1094 void ShenandoahBarrierC2Support::pin_and_expand(PhaseIdealLoop* phase) {
1095 ShenandoahBarrierSetC2State* state = ShenandoahBarrierSetC2::bsc2()->state();
1096
1097 Unique_Node_List uses;
1098 Node_Stack stack(0);
1099 Node_List clones;
1100 for (int i = state->load_reference_barriers_count() - 1; i >= 0; i--) {
1101 ShenandoahLoadReferenceBarrierNode* lrb = state->load_reference_barrier(i);
1102
1103 Node* ctrl = phase->get_ctrl(lrb);
1104 Node* val = lrb->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
1105
1106 CallStaticJavaNode* unc = nullptr;
1107 Node* unc_ctrl = nullptr;
1108 Node* uncasted_val = val;
1109
1110 for (DUIterator_Fast imax, i = lrb->fast_outs(imax); i < imax; i++) {
1111 Node* u = lrb->fast_out(i);
1112 if (u->Opcode() == Op_CastPP &&
1113 u->in(0) != nullptr &&
1114 phase->is_dominator(u->in(0), ctrl)) {
1115 const Type* u_t = phase->igvn().type(u);
1116
1117 if (u_t->meet(TypePtr::NULL_PTR) != u_t &&
1118 u->in(0)->Opcode() == Op_IfTrue &&
1119 u->in(0)->as_Proj()->is_uncommon_trap_if_pattern() &&
1120 u->in(0)->in(0)->is_If() &&
1121 u->in(0)->in(0)->in(1)->Opcode() == Op_Bool &&
1122 u->in(0)->in(0)->in(1)->as_Bool()->_test._test == BoolTest::ne &&
1123 u->in(0)->in(0)->in(1)->in(1)->Opcode() == Op_CmpP &&
1124 u->in(0)->in(0)->in(1)->in(1)->in(1) == val &&
1125 u->in(0)->in(0)->in(1)->in(1)->in(2)->bottom_type() == TypePtr::NULL_PTR) {
1126 IdealLoopTree* loop = phase->get_loop(ctrl);
1127 IdealLoopTree* unc_loop = phase->get_loop(u->in(0));
1128
1129 if (!unc_loop->is_member(loop)) {
1130 continue;
1131 }
1132
1133 Node* branch = no_branches(ctrl, u->in(0), false, phase);
1134 assert(branch == nullptr || branch == NodeSentinel, "was not looking for a branch");
1135 if (branch == NodeSentinel) {
1136 continue;
1137 }
1138
1139 Node* iff = u->in(0)->in(0);
1140 Node* bol = iff->in(1)->clone();
1141 Node* cmp = bol->in(1)->clone();
1142 cmp->set_req(1, lrb);
1143 bol->set_req(1, cmp);
1144 phase->igvn().replace_input_of(iff, 1, bol);
1145 phase->set_ctrl(lrb, iff->in(0));
1146 phase->register_new_node(cmp, iff->in(0));
1147 phase->register_new_node(bol, iff->in(0));
1148 break;
1149 }
1150 }
1151 }
1152 if ((ctrl->is_Proj() && ctrl->in(0)->is_CallJava()) || ctrl->is_CallJava()) {
1153 CallNode* call = ctrl->is_Proj() ? ctrl->in(0)->as_CallJava() : ctrl->as_CallJava();
1154 if (call->entry_point() == OptoRuntime::rethrow_stub()) {
1155 // The rethrow call may have too many projections to be
1156 // properly handled here. Given there's no reason for a
1157 // barrier to depend on the call, move it above the call
1158 stack.push(lrb, 0);
1159 do {
1160 Node* n = stack.node();
1161 uint idx = stack.index();
1162 if (idx < n->req()) {
1163 Node* in = n->in(idx);
1164 stack.set_index(idx+1);
1165 if (in != nullptr) {
1166 if (phase->has_ctrl(in)) {
1167 if (phase->is_dominator(call, phase->get_ctrl(in))) {
1168 #ifdef ASSERT
1169 for (uint i = 0; i < stack.size(); i++) {
1170 assert(stack.node_at(i) != in, "node shouldn't have been seen yet");
1171 }
1172 #endif
1173 stack.push(in, 0);
1174 }
1175 } else {
1176 assert(phase->is_dominator(in, call->in(0)), "no dependency on the call");
1177 }
1178 }
1179 } else {
1180 phase->set_ctrl(n, call->in(0));
1181 stack.pop();
1182 }
1183 } while(stack.size() > 0);
1184 continue;
1185 }
1186 CallProjections projs;
1187 call->extract_projections(&projs, false, false);
1188
1189 #ifdef ASSERT
1190 VectorSet cloned;
1191 #endif
1192 Node* lrb_clone = lrb->clone();
1193 phase->register_new_node(lrb_clone, projs.catchall_catchproj);
1194 phase->set_ctrl(lrb, projs.fallthrough_catchproj);
1195
1196 stack.push(lrb, 0);
1197 clones.push(lrb_clone);
1198
1199 do {
1200 assert(stack.size() == clones.size(), "");
1201 Node* n = stack.node();
1202 #ifdef ASSERT
1203 if (n->is_Load()) {
1204 Node* mem = n->in(MemNode::Memory);
1205 for (DUIterator_Fast jmax, j = mem->fast_outs(jmax); j < jmax; j++) {
1206 Node* u = mem->fast_out(j);
1207 assert(!u->is_Store() || !u->is_LoadStore() || phase->get_ctrl(u) != ctrl, "anti dependent store?");
1208 }
1209 }
1210 #endif
1211 uint idx = stack.index();
1212 Node* n_clone = clones.at(clones.size()-1);
1213 if (idx < n->outcnt()) {
1214 Node* u = n->raw_out(idx);
1215 Node* c = phase->ctrl_or_self(u);
1216 if (phase->is_dominator(call, c) && phase->is_dominator(c, projs.fallthrough_proj)) {
1217 stack.set_index(idx+1);
1218 assert(!u->is_CFG(), "");
1219 stack.push(u, 0);
1220 assert(!cloned.test_set(u->_idx), "only one clone");
1221 Node* u_clone = u->clone();
1222 int nb = u_clone->replace_edge(n, n_clone, &phase->igvn());
1223 assert(nb > 0, "should have replaced some uses");
1224 phase->register_new_node(u_clone, projs.catchall_catchproj);
1225 clones.push(u_clone);
1226 phase->set_ctrl(u, projs.fallthrough_catchproj);
1227 } else {
1228 bool replaced = false;
1229 if (u->is_Phi()) {
1230 for (uint k = 1; k < u->req(); k++) {
1231 if (u->in(k) == n) {
1232 if (phase->is_dominator(projs.catchall_catchproj, u->in(0)->in(k))) {
1233 phase->igvn().replace_input_of(u, k, n_clone);
1234 replaced = true;
1235 } else if (!phase->is_dominator(projs.fallthrough_catchproj, u->in(0)->in(k))) {
1236 phase->igvn().replace_input_of(u, k, create_phis_on_call_return(ctrl, u->in(0)->in(k), n, n_clone, projs, phase));
1237 replaced = true;
1238 }
1239 }
1240 }
1241 } else {
1242 if (phase->is_dominator(projs.catchall_catchproj, c)) {
1243 phase->igvn().rehash_node_delayed(u);
1244 int nb = u->replace_edge(n, n_clone, &phase->igvn());
1245 assert(nb > 0, "should have replaced some uses");
1246 replaced = true;
1247 } else if (!phase->is_dominator(projs.fallthrough_catchproj, c)) {
1248 if (u->is_If()) {
1249 // Can't break If/Bool/Cmp chain
1250 assert(n->is_Bool(), "unexpected If shape");
1251 assert(stack.node_at(stack.size()-2)->is_Cmp(), "unexpected If shape");
1252 assert(n_clone->is_Bool(), "unexpected clone");
1253 assert(clones.at(clones.size()-2)->is_Cmp(), "unexpected clone");
1254 Node* bol_clone = n->clone();
1255 Node* cmp_clone = stack.node_at(stack.size()-2)->clone();
1256 bol_clone->set_req(1, cmp_clone);
1257
1258 Node* nn = stack.node_at(stack.size()-3);
1259 Node* nn_clone = clones.at(clones.size()-3);
1260 assert(nn->Opcode() == nn_clone->Opcode(), "mismatch");
1261
1262 int nb = cmp_clone->replace_edge(nn, create_phis_on_call_return(ctrl, c, nn, nn_clone, projs, phase),
1263 &phase->igvn());
1264 assert(nb > 0, "should have replaced some uses");
1265
1266 phase->register_new_node(bol_clone, u->in(0));
1267 phase->register_new_node(cmp_clone, u->in(0));
1268
1269 phase->igvn().replace_input_of(u, 1, bol_clone);
1270
1271 } else {
1272 phase->igvn().rehash_node_delayed(u);
1273 int nb = u->replace_edge(n, create_phis_on_call_return(ctrl, c, n, n_clone, projs, phase), &phase->igvn());
1274 assert(nb > 0, "should have replaced some uses");
1275 }
1276 replaced = true;
1277 }
1278 }
1279 if (!replaced) {
1280 stack.set_index(idx+1);
1281 }
1282 }
1283 } else {
1284 stack.pop();
1285 clones.pop();
1286 }
1287 } while (stack.size() > 0);
1288 assert(stack.size() == 0 && clones.size() == 0, "");
1289 }
1290 }
1291
1292 for (int i = 0; i < state->load_reference_barriers_count(); i++) {
1293 ShenandoahLoadReferenceBarrierNode* lrb = state->load_reference_barrier(i);
1294 Node* ctrl = phase->get_ctrl(lrb);
1295 IdealLoopTree* loop = phase->get_loop(ctrl);
1296 Node* head = loop->head();
1297 if (head->is_OuterStripMinedLoop()) {
1298 // Expanding a barrier here will break loop strip mining
1299 // verification. Transform the loop so the loop nest doesn't
1300 // appear as strip mined.
1301 OuterStripMinedLoopNode* outer = head->as_OuterStripMinedLoop();
1302 hide_strip_mined_loop(outer, outer->unique_ctrl_out()->as_CountedLoop(), phase);
1303 }
1304 if (head->is_BaseCountedLoop() && ctrl->is_IfProj() && ctrl->in(0)->is_BaseCountedLoopEnd() &&
1305 head->as_BaseCountedLoop()->loopexit() == ctrl->in(0)) {
1306 Node* entry = head->in(LoopNode::EntryControl);
1307 Node* backedge = head->in(LoopNode::LoopBackControl);
1308 Node* new_head = new LoopNode(entry, backedge);
1309 phase->register_control(new_head, phase->get_loop(entry), entry);
1310 phase->lazy_replace(head, new_head);
1311 }
1312 }
1313
1314 // Expand load-reference-barriers
1315 MemoryGraphFixer fixer(Compile::AliasIdxRaw, true, phase);
1316 Unique_Node_List uses_to_ignore;
1317 for (int i = state->load_reference_barriers_count() - 1; i >= 0; i--) {
1318 ShenandoahLoadReferenceBarrierNode* lrb = state->load_reference_barrier(i);
1319 uint last = phase->C->unique();
1320 Node* ctrl = phase->get_ctrl(lrb);
1321 Node* val = lrb->in(ShenandoahLoadReferenceBarrierNode::ValueIn);
1322
1323 Node* orig_ctrl = ctrl;
1324
1325 Node* raw_mem = fixer.find_mem(ctrl, lrb);
1326 Node* raw_mem_for_ctrl = fixer.find_mem(ctrl, nullptr);
1327
1328 IdealLoopTree *loop = phase->get_loop(ctrl);
1329
1330 Node* heap_stable_ctrl = nullptr;
1331 Node* null_ctrl = nullptr;
1332
1333 assert(val->bottom_type()->make_oopptr(), "need oop");
1334 assert(val->bottom_type()->make_oopptr()->const_oop() == nullptr, "expect non-constant");
1335
1336 enum { _heap_stable = 1, _evac_path, _not_cset, PATH_LIMIT };
1337 Node* region = new RegionNode(PATH_LIMIT);
1338 Node* val_phi = new PhiNode(region, val->bottom_type()->is_oopptr());
1339
1340 // Stable path.
1341 int flags = ShenandoahHeap::HAS_FORWARDED;
1342 if (!ShenandoahBarrierSet::is_strong_access(lrb->decorators())) {
1343 flags |= ShenandoahHeap::WEAK_ROOTS;
1344 }
1345 test_gc_state(ctrl, raw_mem, heap_stable_ctrl, phase, flags);
1346 IfNode* heap_stable_iff = heap_stable_ctrl->in(0)->as_If();
1347
1348 // Heap stable case
1349 region->init_req(_heap_stable, heap_stable_ctrl);
1350 val_phi->init_req(_heap_stable, val);
1351
1352 // Test for in-cset, unless it's a native-LRB. Native LRBs need to return null
1353 // even for non-cset objects to prevent resurrection of such objects.
1354 // Wires !in_cset(obj) to slot 2 of region and phis
1355 Node* not_cset_ctrl = nullptr;
1356 if (ShenandoahBarrierSet::is_strong_access(lrb->decorators())) {
1357 test_in_cset(ctrl, not_cset_ctrl, val, raw_mem, phase);
1358 }
1359 if (not_cset_ctrl != nullptr) {
1360 region->init_req(_not_cset, not_cset_ctrl);
1361 val_phi->init_req(_not_cset, val);
1362 } else {
1363 region->del_req(_not_cset);
1364 val_phi->del_req(_not_cset);
1365 }
1366
1367 // Resolve object when orig-value is in cset.
1368 // Make the unconditional resolve for fwdptr.
1369
1370 // Call lrb-stub and wire up that path in slots 4
1371 Node* result_mem = nullptr;
1372
1373 Node* addr;
1374 {
1375 VectorSet visited;
1376 addr = get_load_addr(phase, visited, lrb);
1377 }
1378 if (addr->Opcode() == Op_AddP) {
1379 Node* orig_base = addr->in(AddPNode::Base);
1380 Node* base = new CheckCastPPNode(ctrl, orig_base, orig_base->bottom_type(), ConstraintCastNode::StrongDependency);
1381 phase->register_new_node(base, ctrl);
1382 if (addr->in(AddPNode::Base) == addr->in((AddPNode::Address))) {
1383 // Field access
1384 addr = addr->clone();
1385 addr->set_req(AddPNode::Base, base);
1386 addr->set_req(AddPNode::Address, base);
1387 phase->register_new_node(addr, ctrl);
1388 } else {
1389 Node* addr2 = addr->in(AddPNode::Address);
1390 if (addr2->Opcode() == Op_AddP && addr2->in(AddPNode::Base) == addr2->in(AddPNode::Address) &&
1391 addr2->in(AddPNode::Base) == orig_base) {
1392 addr2 = addr2->clone();
1393 addr2->set_req(AddPNode::Base, base);
1394 addr2->set_req(AddPNode::Address, base);
1395 phase->register_new_node(addr2, ctrl);
1396 addr = addr->clone();
1397 addr->set_req(AddPNode::Base, base);
1398 addr->set_req(AddPNode::Address, addr2);
1399 phase->register_new_node(addr, ctrl);
1400 }
1401 }
1402 }
1403 call_lrb_stub(ctrl, val, addr, lrb->decorators(), phase);
1404 region->init_req(_evac_path, ctrl);
1405 val_phi->init_req(_evac_path, val);
1406
1407 phase->register_control(region, loop, heap_stable_iff);
1408 Node* out_val = val_phi;
1409 phase->register_new_node(val_phi, region);
1410
1411 fix_ctrl(lrb, region, fixer, uses, uses_to_ignore, last, phase);
1412
1413 ctrl = orig_ctrl;
1414
1415 phase->igvn().replace_node(lrb, out_val);
1416
1417 follow_barrier_uses(out_val, ctrl, uses, phase);
1418
1419 for(uint next = 0; next < uses.size(); next++ ) {
1420 Node *n = uses.at(next);
1421 assert(phase->get_ctrl(n) == ctrl, "bad control");
1422 assert(n != raw_mem, "should leave input raw mem above the barrier");
1423 phase->set_ctrl(n, region);
1424 follow_barrier_uses(n, ctrl, uses, phase);
1425 }
1426 fixer.record_new_ctrl(ctrl, region, raw_mem, raw_mem_for_ctrl);
1427 }
1428 // Done expanding load-reference-barriers.
1429 assert(ShenandoahBarrierSetC2::bsc2()->state()->load_reference_barriers_count() == 0, "all load reference barrier nodes should have been replaced");
1430 }
1431
1432 Node* ShenandoahBarrierC2Support::get_load_addr(PhaseIdealLoop* phase, VectorSet& visited, Node* in) {
1433 if (visited.test_set(in->_idx)) {
1434 return nullptr;
1435 }
1436 switch (in->Opcode()) {
1437 case Op_Proj:
1438 return get_load_addr(phase, visited, in->in(0));
1439 case Op_CastPP:
1440 case Op_CheckCastPP:
1441 case Op_DecodeN:
1442 case Op_EncodeP:
1443 return get_load_addr(phase, visited, in->in(1));
1444 case Op_LoadN:
1445 case Op_LoadP:
1446 return in->in(MemNode::Address);
1447 case Op_CompareAndExchangeN:
1448 case Op_CompareAndExchangeP:
1449 case Op_GetAndSetN:
1450 case Op_GetAndSetP:
1451 case Op_ShenandoahCompareAndExchangeP:
1452 case Op_ShenandoahCompareAndExchangeN:
1453 // Those instructions would just have stored a different
1454 // value into the field. No use to attempt to fix it at this point.
1455 return phase->igvn().zerocon(T_OBJECT);
1456 case Op_CMoveP:
1457 case Op_CMoveN: {
1458 Node* t = get_load_addr(phase, visited, in->in(CMoveNode::IfTrue));
1459 Node* f = get_load_addr(phase, visited, in->in(CMoveNode::IfFalse));
1460 // Handle unambiguous cases: single address reported on both branches.
1461 if (t != nullptr && f == nullptr) return t;
1462 if (t == nullptr && f != nullptr) return f;
1463 if (t != nullptr && t == f) return t;
1464 // Ambiguity.
1465 return phase->igvn().zerocon(T_OBJECT);
1466 }
1467 case Op_Phi: {
1468 Node* addr = nullptr;
1469 for (uint i = 1; i < in->req(); i++) {
1470 Node* addr1 = get_load_addr(phase, visited, in->in(i));
1471 if (addr == nullptr) {
1472 addr = addr1;
1473 }
1474 if (addr != addr1) {
1475 return phase->igvn().zerocon(T_OBJECT);
1476 }
1477 }
1478 return addr;
1479 }
1480 case Op_ShenandoahLoadReferenceBarrier:
1481 return get_load_addr(phase, visited, in->in(ShenandoahLoadReferenceBarrierNode::ValueIn));
1482 case Op_CallDynamicJava:
1483 case Op_CallLeaf:
1484 case Op_CallStaticJava:
1485 case Op_ConN:
1486 case Op_ConP:
1487 case Op_Parm:
1488 case Op_CreateEx:
1489 return phase->igvn().zerocon(T_OBJECT);
1490 default:
1491 #ifdef ASSERT
1492 fatal("Unknown node in get_load_addr: %s", NodeClassNames[in->Opcode()]);
1493 #endif
1494 return phase->igvn().zerocon(T_OBJECT);
1495 }
1496
1497 }
1498
1499 void ShenandoahBarrierC2Support::move_gc_state_test_out_of_loop(IfNode* iff, PhaseIdealLoop* phase) {
1500 IdealLoopTree *loop = phase->get_loop(iff);
1501 Node* loop_head = loop->_head;
1502 Node* entry_c = loop_head->in(LoopNode::EntryControl);
1503
1504 Node* bol = iff->in(1);
1505 Node* cmp = bol->in(1);
1506 Node* andi = cmp->in(1);
1507 Node* load = andi->in(1);
1508
1509 assert(is_gc_state_load(load), "broken");
1510 if (!phase->is_dominator(load->in(0), entry_c)) {
1511 Node* mem_ctrl = nullptr;
1512 Node* mem = dom_mem(load->in(MemNode::Memory), loop_head, Compile::AliasIdxRaw, mem_ctrl, phase);
1513 load = load->clone();
1514 load->set_req(MemNode::Memory, mem);
1515 load->set_req(0, entry_c);
1516 phase->register_new_node(load, entry_c);
1517 andi = andi->clone();
1518 andi->set_req(1, load);
1519 phase->register_new_node(andi, entry_c);
1520 cmp = cmp->clone();
1521 cmp->set_req(1, andi);
1522 phase->register_new_node(cmp, entry_c);
1523 bol = bol->clone();
1524 bol->set_req(1, cmp);
1525 phase->register_new_node(bol, entry_c);
1526
1527 phase->igvn().replace_input_of(iff, 1, bol);
1528 }
1529 }
1530
1531 bool ShenandoahBarrierC2Support::identical_backtoback_ifs(Node* n, PhaseIdealLoop* phase) {
1532 if (!n->is_If() || n->is_CountedLoopEnd()) {
1533 return false;
1534 }
1535 Node* region = n->in(0);
1536
1537 if (!region->is_Region()) {
1538 return false;
1539 }
1540 Node* dom = phase->idom(region);
1541 if (!dom->is_If()) {
1542 return false;
1543 }
1544
1545 if (!is_heap_stable_test(n) || !is_heap_stable_test(dom)) {
1546 return false;
1547 }
1548
1549 IfNode* dom_if = dom->as_If();
1550 Node* proj_true = dom_if->proj_out(1);
1551 Node* proj_false = dom_if->proj_out(0);
1552
1553 for (uint i = 1; i < region->req(); i++) {
1554 if (phase->is_dominator(proj_true, region->in(i))) {
1555 continue;
1556 }
1557 if (phase->is_dominator(proj_false, region->in(i))) {
1558 continue;
1559 }
1560 return false;
1561 }
1562
1563 return true;
1564 }
1565
1566 bool ShenandoahBarrierC2Support::merge_point_safe(Node* region) {
1567 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
1568 Node* n = region->fast_out(i);
1569 if (n->is_LoadStore()) {
1570 // Splitting a LoadStore node through phi, causes it to lose its SCMemProj: the split if code doesn't have support
1571 // for a LoadStore at the region the if is split through because that's not expected to happen (LoadStore nodes
1572 // should be between barrier nodes). It does however happen with Shenandoah though because barriers can get
1573 // expanded around a LoadStore node.
1574 return false;
1575 }
1576 }
1577 return true;
1578 }
1579
1580
1581 void ShenandoahBarrierC2Support::merge_back_to_back_tests(Node* n, PhaseIdealLoop* phase) {
1582 assert(is_heap_stable_test(n), "no other tests");
1583 if (identical_backtoback_ifs(n, phase)) {
1584 Node* n_ctrl = n->in(0);
1585 if (phase->can_split_if(n_ctrl) && merge_point_safe(n_ctrl)) {
1586 IfNode* dom_if = phase->idom(n_ctrl)->as_If();
1587 if (is_heap_stable_test(n)) {
1588 Node* gc_state_load = n->in(1)->in(1)->in(1)->in(1);
1589 assert(is_gc_state_load(gc_state_load), "broken");
1590 Node* dom_gc_state_load = dom_if->in(1)->in(1)->in(1)->in(1);
1591 assert(is_gc_state_load(dom_gc_state_load), "broken");
1592 if (gc_state_load != dom_gc_state_load) {
1593 phase->igvn().replace_node(gc_state_load, dom_gc_state_load);
1594 }
1595 }
1596 PhiNode* bolphi = PhiNode::make_blank(n_ctrl, n->in(1));
1597 Node* proj_true = dom_if->proj_out(1);
1598 Node* proj_false = dom_if->proj_out(0);
1599 Node* con_true = phase->igvn().makecon(TypeInt::ONE);
1600 Node* con_false = phase->igvn().makecon(TypeInt::ZERO);
1601
1602 for (uint i = 1; i < n_ctrl->req(); i++) {
1603 if (phase->is_dominator(proj_true, n_ctrl->in(i))) {
1604 bolphi->init_req(i, con_true);
1605 } else {
1606 assert(phase->is_dominator(proj_false, n_ctrl->in(i)), "bad if");
1607 bolphi->init_req(i, con_false);
1608 }
1609 }
1610 phase->register_new_node(bolphi, n_ctrl);
1611 phase->igvn().replace_input_of(n, 1, bolphi);
1612 phase->do_split_if(n);
1613 }
1614 }
1615 }
1616
1617 IfNode* ShenandoahBarrierC2Support::find_unswitching_candidate(const IdealLoopTree* loop, PhaseIdealLoop* phase) {
1618 // Find first invariant test that doesn't exit the loop
1619 LoopNode *head = loop->_head->as_Loop();
1620 IfNode* unswitch_iff = nullptr;
1621 Node* n = head->in(LoopNode::LoopBackControl);
1622 int loop_has_sfpts = -1;
1623 while (n != head) {
1624 Node* n_dom = phase->idom(n);
1625 if (n->is_Region()) {
1626 if (n_dom->is_If()) {
1627 IfNode* iff = n_dom->as_If();
1628 if (iff->in(1)->is_Bool()) {
1629 BoolNode* bol = iff->in(1)->as_Bool();
1630 if (bol->in(1)->is_Cmp()) {
1631 // If condition is invariant and not a loop exit,
1632 // then found reason to unswitch.
1633 if (is_heap_stable_test(iff) &&
1634 (loop_has_sfpts == -1 || loop_has_sfpts == 0)) {
1635 assert(!loop->is_loop_exit(iff), "both branches should be in the loop");
1636 if (loop_has_sfpts == -1) {
1637 for(uint i = 0; i < loop->_body.size(); i++) {
1638 Node *m = loop->_body[i];
1639 if (m->is_SafePoint() && !m->is_CallLeaf()) {
1640 loop_has_sfpts = 1;
1641 break;
1642 }
1643 }
1644 if (loop_has_sfpts == -1) {
1645 loop_has_sfpts = 0;
1646 }
1647 }
1648 if (!loop_has_sfpts) {
1649 unswitch_iff = iff;
1650 }
1651 }
1652 }
1653 }
1654 }
1655 }
1656 n = n_dom;
1657 }
1658 return unswitch_iff;
1659 }
1660
1661
1662 void ShenandoahBarrierC2Support::optimize_after_expansion(VectorSet &visited, Node_Stack &stack, Node_List &old_new, PhaseIdealLoop* phase) {
1663 Node_List heap_stable_tests;
1664 stack.push(phase->C->start(), 0);
1665 do {
1666 Node* n = stack.node();
1667 uint i = stack.index();
1668
1669 if (i < n->outcnt()) {
1670 Node* u = n->raw_out(i);
1671 stack.set_index(i+1);
1672 if (!visited.test_set(u->_idx)) {
1673 stack.push(u, 0);
1674 }
1675 } else {
1676 stack.pop();
1677 if (n->is_If() && is_heap_stable_test(n)) {
1678 heap_stable_tests.push(n);
1679 }
1680 }
1681 } while (stack.size() > 0);
1682
1683 for (uint i = 0; i < heap_stable_tests.size(); i++) {
1684 Node* n = heap_stable_tests.at(i);
1685 assert(is_heap_stable_test(n), "only evacuation test");
1686 merge_back_to_back_tests(n, phase);
1687 }
1688
1689 if (!phase->C->major_progress()) {
1690 VectorSet seen;
1691 for (uint i = 0; i < heap_stable_tests.size(); i++) {
1692 Node* n = heap_stable_tests.at(i);
1693 IdealLoopTree* loop = phase->get_loop(n);
1694 if (loop != phase->ltree_root() &&
1695 loop->_child == nullptr &&
1696 !loop->_irreducible) {
1697 Node* head = loop->_head;
1698 if (head->is_Loop() &&
1699 (!head->is_CountedLoop() || head->as_CountedLoop()->is_main_loop() || head->as_CountedLoop()->is_normal_loop()) &&
1700 !seen.test_set(head->_idx)) {
1701 IfNode* iff = find_unswitching_candidate(loop, phase);
1702 if (iff != nullptr) {
1703 Node* bol = iff->in(1);
1704 if (head->as_Loop()->is_strip_mined()) {
1705 head->as_Loop()->verify_strip_mined(0);
1706 }
1707 move_gc_state_test_out_of_loop(iff, phase);
1708
1709 AutoNodeBudget node_budget(phase);
1710
1711 if (loop->policy_unswitching(phase)) {
1712 if (head->as_Loop()->is_strip_mined()) {
1713 OuterStripMinedLoopNode* outer = head->as_CountedLoop()->outer_loop();
1714 hide_strip_mined_loop(outer, head->as_CountedLoop(), phase);
1715 }
1716 phase->do_unswitching(loop, old_new);
1717 } else {
1718 // Not proceeding with unswitching. Move load back in
1719 // the loop.
1720 phase->igvn().replace_input_of(iff, 1, bol);
1721 }
1722 }
1723 }
1724 }
1725 }
1726 }
1727 }
1728
1729 #ifdef ASSERT
1730 static bool has_never_branch(Node* root) {
1731 for (uint i = 1; i < root->req(); i++) {
1732 Node* in = root->in(i);
1733 if (in != nullptr && in->Opcode() == Op_Halt && in->in(0)->is_Proj() && in->in(0)->in(0)->is_NeverBranch()) {
1734 return true;
1735 }
1736 }
1737 return false;
1738 }
1739 #endif
1740
1741 void MemoryGraphFixer::collect_memory_nodes() {
1742 Node_Stack stack(0);
1743 VectorSet visited;
1744 Node_List regions;
1745
1746 // Walk the raw memory graph and create a mapping from CFG node to
1747 // memory node. Exclude phis for now.
1748 stack.push(_phase->C->root(), 1);
1749 do {
1750 Node* n = stack.node();
1751 int opc = n->Opcode();
1752 uint i = stack.index();
1753 if (i < n->req()) {
1754 Node* mem = nullptr;
1755 if (opc == Op_Root) {
1756 Node* in = n->in(i);
1757 int in_opc = in->Opcode();
1758 if (in_opc == Op_Return || in_opc == Op_Rethrow) {
1759 mem = in->in(TypeFunc::Memory);
1760 } else if (in_opc == Op_Halt) {
1761 if (in->in(0)->is_Region()) {
1762 Node* r = in->in(0);
1763 for (uint j = 1; j < r->req(); j++) {
1764 assert(!r->in(j)->is_NeverBranch(), "");
1765 }
1766 } else {
1767 Node* proj = in->in(0);
1768 assert(proj->is_Proj(), "");
1769 Node* in = proj->in(0);
1770 assert(in->is_CallStaticJava() || in->is_NeverBranch() || in->Opcode() == Op_Catch || proj->is_IfProj(), "");
1771 if (in->is_CallStaticJava()) {
1772 mem = in->in(TypeFunc::Memory);
1773 } else if (in->Opcode() == Op_Catch) {
1774 Node* call = in->in(0)->in(0);
1775 assert(call->is_Call(), "");
1776 mem = call->in(TypeFunc::Memory);
1777 } else if (in->is_NeverBranch()) {
1778 mem = collect_memory_for_infinite_loop(in);
1779 }
1780 }
1781 } else {
1782 #ifdef ASSERT
1783 n->dump();
1784 in->dump();
1785 #endif
1786 ShouldNotReachHere();
1787 }
1788 } else {
1789 assert(n->is_Phi() && n->bottom_type() == Type::MEMORY, "");
1790 assert(n->adr_type() == TypePtr::BOTTOM || _phase->C->get_alias_index(n->adr_type()) == _alias, "");
1791 mem = n->in(i);
1792 }
1793 i++;
1794 stack.set_index(i);
1795 if (mem == nullptr) {
1796 continue;
1797 }
1798 for (;;) {
1799 if (visited.test_set(mem->_idx) || mem->is_Start()) {
1800 break;
1801 }
1802 if (mem->is_Phi()) {
1803 stack.push(mem, 2);
1804 mem = mem->in(1);
1805 } else if (mem->is_Proj()) {
1806 stack.push(mem, mem->req());
1807 mem = mem->in(0);
1808 } else if (mem->is_SafePoint() || mem->is_MemBar()) {
1809 mem = mem->in(TypeFunc::Memory);
1810 } else if (mem->is_MergeMem()) {
1811 MergeMemNode* mm = mem->as_MergeMem();
1812 mem = mm->memory_at(_alias);
1813 } else if (mem->is_Store() || mem->is_LoadStore() || mem->is_ClearArray()) {
1814 assert(_alias == Compile::AliasIdxRaw, "");
1815 stack.push(mem, mem->req());
1816 mem = mem->in(MemNode::Memory);
1817 } else {
1818 #ifdef ASSERT
1819 mem->dump();
1820 #endif
1821 ShouldNotReachHere();
1822 }
1823 }
1824 } else {
1825 if (n->is_Phi()) {
1826 // Nothing
1827 } else if (!n->is_Root()) {
1828 Node* c = get_ctrl(n);
1829 _memory_nodes.map(c->_idx, n);
1830 }
1831 stack.pop();
1832 }
1833 } while(stack.is_nonempty());
1834
1835 // Iterate over CFG nodes in rpo and propagate memory state to
1836 // compute memory state at regions, creating new phis if needed.
1837 Node_List rpo_list;
1838 visited.clear();
1839 _phase->rpo(_phase->C->root(), stack, visited, rpo_list);
1840 Node* root = rpo_list.pop();
1841 assert(root == _phase->C->root(), "");
1842
1843 const bool trace = false;
1844 #ifdef ASSERT
1845 if (trace) {
1846 for (int i = rpo_list.size() - 1; i >= 0; i--) {
1847 Node* c = rpo_list.at(i);
1848 if (_memory_nodes[c->_idx] != nullptr) {
1849 tty->print("X %d", c->_idx); _memory_nodes[c->_idx]->dump();
1850 }
1851 }
1852 }
1853 #endif
1854 uint last = _phase->C->unique();
1855
1856 #ifdef ASSERT
1857 uint16_t max_depth = 0;
1858 for (LoopTreeIterator iter(_phase->ltree_root()); !iter.done(); iter.next()) {
1859 IdealLoopTree* lpt = iter.current();
1860 max_depth = MAX2(max_depth, lpt->_nest);
1861 }
1862 #endif
1863
1864 bool progress = true;
1865 int iteration = 0;
1866 Node_List dead_phis;
1867 while (progress) {
1868 progress = false;
1869 iteration++;
1870 assert(iteration <= 2+max_depth || _phase->C->has_irreducible_loop() || has_never_branch(_phase->C->root()), "");
1871 if (trace) { tty->print_cr("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"); }
1872
1873 for (int i = rpo_list.size() - 1; i >= 0; i--) {
1874 Node* c = rpo_list.at(i);
1875
1876 Node* prev_mem = _memory_nodes[c->_idx];
1877 if (c->is_Region() && (_include_lsm || !c->is_OuterStripMinedLoop())) {
1878 Node* prev_region = regions[c->_idx];
1879 Node* unique = nullptr;
1880 for (uint j = 1; j < c->req() && unique != NodeSentinel; j++) {
1881 Node* m = _memory_nodes[c->in(j)->_idx];
1882 assert(m != nullptr || (c->is_Loop() && j == LoopNode::LoopBackControl && iteration == 1) || _phase->C->has_irreducible_loop() || has_never_branch(_phase->C->root()), "expect memory state");
1883 if (m != nullptr) {
1884 if (m == prev_region && ((c->is_Loop() && j == LoopNode::LoopBackControl) || (prev_region->is_Phi() && prev_region->in(0) == c))) {
1885 assert((c->is_Loop() && j == LoopNode::LoopBackControl) || _phase->C->has_irreducible_loop() || has_never_branch(_phase->C->root()), "");
1886 // continue
1887 } else if (unique == nullptr) {
1888 unique = m;
1889 } else if (m == unique) {
1890 // continue
1891 } else {
1892 unique = NodeSentinel;
1893 }
1894 }
1895 }
1896 assert(unique != nullptr, "empty phi???");
1897 if (unique != NodeSentinel) {
1898 if (prev_region != nullptr && prev_region->is_Phi() && prev_region->in(0) == c) {
1899 dead_phis.push(prev_region);
1900 }
1901 regions.map(c->_idx, unique);
1902 } else {
1903 Node* phi = nullptr;
1904 if (prev_region != nullptr && prev_region->is_Phi() && prev_region->in(0) == c && prev_region->_idx >= last) {
1905 phi = prev_region;
1906 for (uint k = 1; k < c->req(); k++) {
1907 Node* m = _memory_nodes[c->in(k)->_idx];
1908 assert(m != nullptr, "expect memory state");
1909 phi->set_req(k, m);
1910 }
1911 } else {
1912 for (DUIterator_Fast jmax, j = c->fast_outs(jmax); j < jmax && phi == nullptr; j++) {
1913 Node* u = c->fast_out(j);
1914 if (u->is_Phi() && u->bottom_type() == Type::MEMORY &&
1915 (u->adr_type() == TypePtr::BOTTOM || _phase->C->get_alias_index(u->adr_type()) == _alias)) {
1916 phi = u;
1917 for (uint k = 1; k < c->req() && phi != nullptr; k++) {
1918 Node* m = _memory_nodes[c->in(k)->_idx];
1919 assert(m != nullptr, "expect memory state");
1920 if (u->in(k) != m) {
1921 phi = NodeSentinel;
1922 }
1923 }
1924 }
1925 }
1926 if (phi == NodeSentinel) {
1927 phi = new PhiNode(c, Type::MEMORY, _phase->C->get_adr_type(_alias));
1928 for (uint k = 1; k < c->req(); k++) {
1929 Node* m = _memory_nodes[c->in(k)->_idx];
1930 assert(m != nullptr, "expect memory state");
1931 phi->init_req(k, m);
1932 }
1933 }
1934 }
1935 if (phi != nullptr) {
1936 regions.map(c->_idx, phi);
1937 } else {
1938 assert(c->unique_ctrl_out()->Opcode() == Op_Halt, "expected memory state");
1939 }
1940 }
1941 Node* current_region = regions[c->_idx];
1942 if (current_region != prev_region) {
1943 progress = true;
1944 if (prev_region == prev_mem) {
1945 _memory_nodes.map(c->_idx, current_region);
1946 }
1947 }
1948 } else if (prev_mem == nullptr || prev_mem->is_Phi() || ctrl_or_self(prev_mem) != c) {
1949 Node* m = _memory_nodes[_phase->idom(c)->_idx];
1950 assert(m != nullptr || c->Opcode() == Op_Halt, "expect memory state");
1951 if (m != prev_mem) {
1952 _memory_nodes.map(c->_idx, m);
1953 progress = true;
1954 }
1955 }
1956 #ifdef ASSERT
1957 if (trace) { tty->print("X %d", c->_idx); _memory_nodes[c->_idx]->dump(); }
1958 #endif
1959 }
1960 }
1961
1962 // Replace existing phi with computed memory state for that region
1963 // if different (could be a new phi or a dominating memory node if
1964 // that phi was found to be useless).
1965 while (dead_phis.size() > 0) {
1966 Node* n = dead_phis.pop();
1967 n->replace_by(_phase->C->top());
1968 n->destruct(&_phase->igvn());
1969 }
1970 for (int i = rpo_list.size() - 1; i >= 0; i--) {
1971 Node* c = rpo_list.at(i);
1972 if (c->is_Region() && (_include_lsm || !c->is_OuterStripMinedLoop())) {
1973 Node* n = regions[c->_idx];
1974 assert(n != nullptr || c->unique_ctrl_out()->Opcode() == Op_Halt, "expected memory state");
1975 if (n != nullptr && n->is_Phi() && n->_idx >= last && n->in(0) == c) {
1976 _phase->register_new_node(n, c);
1977 }
1978 }
1979 }
1980 for (int i = rpo_list.size() - 1; i >= 0; i--) {
1981 Node* c = rpo_list.at(i);
1982 if (c->is_Region() && (_include_lsm || !c->is_OuterStripMinedLoop())) {
1983 Node* n = regions[c->_idx];
1984 assert(n != nullptr || c->unique_ctrl_out()->Opcode() == Op_Halt, "expected memory state");
1985 for (DUIterator_Fast imax, i = c->fast_outs(imax); i < imax; i++) {
1986 Node* u = c->fast_out(i);
1987 if (u->is_Phi() && u->bottom_type() == Type::MEMORY &&
1988 u != n) {
1989 assert(c->unique_ctrl_out()->Opcode() != Op_Halt, "expected memory state");
1990 if (u->adr_type() == TypePtr::BOTTOM) {
1991 fix_memory_uses(u, n, n, c);
1992 } else if (_phase->C->get_alias_index(u->adr_type()) == _alias) {
1993 _phase->lazy_replace(u, n);
1994 --i; --imax;
1995 }
1996 }
1997 }
1998 }
1999 }
2000 }
2001
2002 Node* MemoryGraphFixer::collect_memory_for_infinite_loop(const Node* in) {
2003 Node* mem = nullptr;
2004 Node* head = in->in(0);
2005 assert(head->is_Region(), "unexpected infinite loop graph shape");
2006
2007 Node* phi_mem = nullptr;
2008 for (DUIterator_Fast jmax, j = head->fast_outs(jmax); j < jmax; j++) {
2009 Node* u = head->fast_out(j);
2010 if (u->is_Phi() && u->bottom_type() == Type::MEMORY) {
2011 if (_phase->C->get_alias_index(u->adr_type()) == _alias) {
2012 assert(phi_mem == nullptr || phi_mem->adr_type() == TypePtr::BOTTOM, "");
2013 phi_mem = u;
2014 } else if (u->adr_type() == TypePtr::BOTTOM) {
2015 assert(phi_mem == nullptr || _phase->C->get_alias_index(phi_mem->adr_type()) == _alias, "");
2016 if (phi_mem == nullptr) {
2017 phi_mem = u;
2018 }
2019 }
2020 }
2021 }
2022 if (phi_mem == nullptr) {
2023 ResourceMark rm;
2024 Node_Stack stack(0);
2025 stack.push(head, 1);
2026 do {
2027 Node* n = stack.node();
2028 uint i = stack.index();
2029 if (i >= n->req()) {
2030 stack.pop();
2031 } else {
2032 stack.set_index(i + 1);
2033 Node* c = n->in(i);
2034 assert(c != head, "should have found a safepoint on the way");
2035 if (stack.size() != 1 || _phase->is_dominator(head, c)) {
2036 for (;;) {
2037 if (c->is_Region()) {
2038 stack.push(c, 1);
2039 break;
2040 } else if (c->is_SafePoint() && !c->is_CallLeaf()) {
2041 Node* m = c->in(TypeFunc::Memory);
2042 if (m->is_MergeMem()) {
2043 m = m->as_MergeMem()->memory_at(_alias);
2044 }
2045 assert(mem == nullptr || mem == m, "several memory states");
2046 mem = m;
2047 break;
2048 } else {
2049 assert(c != c->in(0), "");
2050 c = c->in(0);
2051 }
2052 }
2053 }
2054 }
2055 } while (stack.size() > 0);
2056 assert(mem != nullptr, "should have found safepoint");
2057 } else {
2058 mem = phi_mem;
2059 }
2060 return mem;
2061 }
2062
2063 Node* MemoryGraphFixer::get_ctrl(Node* n) const {
2064 Node* c = _phase->get_ctrl(n);
2065 if (n->is_Proj() && n->in(0) != nullptr && n->in(0)->is_Call()) {
2066 assert(c == n->in(0), "");
2067 CallNode* call = c->as_Call();
2068 CallProjections projs;
2069 call->extract_projections(&projs, true, false);
2070 if (projs.catchall_memproj != nullptr) {
2071 if (projs.fallthrough_memproj == n) {
2072 c = projs.fallthrough_catchproj;
2073 } else {
2074 assert(projs.catchall_memproj == n, "");
2075 c = projs.catchall_catchproj;
2076 }
2077 }
2078 }
2079 return c;
2080 }
2081
2082 Node* MemoryGraphFixer::ctrl_or_self(Node* n) const {
2083 if (_phase->has_ctrl(n))
2084 return get_ctrl(n);
2085 else {
2086 assert (n->is_CFG(), "must be a CFG node");
2087 return n;
2088 }
2089 }
2090
2091 bool MemoryGraphFixer::mem_is_valid(Node* m, Node* c) const {
2092 return m != nullptr && get_ctrl(m) == c;
2093 }
2094
2095 Node* MemoryGraphFixer::find_mem(Node* ctrl, Node* n) const {
2096 assert(n == nullptr || _phase->ctrl_or_self(n) == ctrl, "");
2097 assert(!ctrl->is_Call() || ctrl == n, "projection expected");
2098 #ifdef ASSERT
2099 if ((ctrl->is_Proj() && ctrl->in(0)->is_Call()) ||
2100 (ctrl->is_Catch() && ctrl->in(0)->in(0)->is_Call())) {
2101 CallNode* call = ctrl->is_Proj() ? ctrl->in(0)->as_Call() : ctrl->in(0)->in(0)->as_Call();
2102 int mems = 0;
2103 for (DUIterator_Fast imax, i = call->fast_outs(imax); i < imax; i++) {
2104 Node* u = call->fast_out(i);
2105 if (u->bottom_type() == Type::MEMORY) {
2106 mems++;
2107 }
2108 }
2109 assert(mems <= 1, "No node right after call if multiple mem projections");
2110 }
2111 #endif
2112 Node* mem = _memory_nodes[ctrl->_idx];
2113 Node* c = ctrl;
2114 while (!mem_is_valid(mem, c) &&
2115 (!c->is_CatchProj() || mem == nullptr || c->in(0)->in(0)->in(0) != get_ctrl(mem))) {
2116 c = _phase->idom(c);
2117 mem = _memory_nodes[c->_idx];
2118 }
2119 if (n != nullptr && mem_is_valid(mem, c)) {
2120 while (!ShenandoahBarrierC2Support::is_dominator_same_ctrl(c, mem, n, _phase) && _phase->ctrl_or_self(mem) == ctrl) {
2121 mem = next_mem(mem, _alias);
2122 }
2123 if (mem->is_MergeMem()) {
2124 mem = mem->as_MergeMem()->memory_at(_alias);
2125 }
2126 if (!mem_is_valid(mem, c)) {
2127 do {
2128 c = _phase->idom(c);
2129 mem = _memory_nodes[c->_idx];
2130 } while (!mem_is_valid(mem, c) &&
2131 (!c->is_CatchProj() || mem == nullptr || c->in(0)->in(0)->in(0) != get_ctrl(mem)));
2132 }
2133 }
2134 assert(mem->bottom_type() == Type::MEMORY, "");
2135 return mem;
2136 }
2137
2138 bool MemoryGraphFixer::has_mem_phi(Node* region) const {
2139 for (DUIterator_Fast imax, i = region->fast_outs(imax); i < imax; i++) {
2140 Node* use = region->fast_out(i);
2141 if (use->is_Phi() && use->bottom_type() == Type::MEMORY &&
2142 (_phase->C->get_alias_index(use->adr_type()) == _alias)) {
2143 return true;
2144 }
2145 }
2146 return false;
2147 }
2148
2149 void MemoryGraphFixer::fix_mem(Node* ctrl, Node* new_ctrl, Node* mem, Node* mem_for_ctrl, Node* new_mem, Unique_Node_List& uses) {
2150 assert(_phase->ctrl_or_self(new_mem) == new_ctrl, "");
2151 const bool trace = false;
2152 DEBUG_ONLY(if (trace) { tty->print("ZZZ control is"); ctrl->dump(); });
2153 DEBUG_ONLY(if (trace) { tty->print("ZZZ mem is"); mem->dump(); });
2154 GrowableArray<Node*> phis;
2155 if (mem_for_ctrl != mem) {
2156 Node* old = mem_for_ctrl;
2157 Node* prev = nullptr;
2158 while (old != mem) {
2159 prev = old;
2160 if (old->is_Store() || old->is_ClearArray() || old->is_LoadStore()) {
2161 assert(_alias == Compile::AliasIdxRaw, "");
2162 old = old->in(MemNode::Memory);
2163 } else if (old->Opcode() == Op_SCMemProj) {
2164 assert(_alias == Compile::AliasIdxRaw, "");
2165 old = old->in(0);
2166 } else {
2167 ShouldNotReachHere();
2168 }
2169 }
2170 assert(prev != nullptr, "");
2171 if (new_ctrl != ctrl) {
2172 _memory_nodes.map(ctrl->_idx, mem);
2173 _memory_nodes.map(new_ctrl->_idx, mem_for_ctrl);
2174 }
2175 uint input = (uint)MemNode::Memory;
2176 _phase->igvn().replace_input_of(prev, input, new_mem);
2177 } else {
2178 uses.clear();
2179 _memory_nodes.map(new_ctrl->_idx, new_mem);
2180 uses.push(new_ctrl);
2181 for(uint next = 0; next < uses.size(); next++ ) {
2182 Node *n = uses.at(next);
2183 assert(n->is_CFG(), "");
2184 DEBUG_ONLY(if (trace) { tty->print("ZZZ ctrl"); n->dump(); });
2185 for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2186 Node* u = n->fast_out(i);
2187 if (!u->is_Root() && u->is_CFG() && u != n) {
2188 Node* m = _memory_nodes[u->_idx];
2189 if (u->is_Region() && (!u->is_OuterStripMinedLoop() || _include_lsm) &&
2190 !has_mem_phi(u) &&
2191 u->unique_ctrl_out()->Opcode() != Op_Halt) {
2192 DEBUG_ONLY(if (trace) { tty->print("ZZZ region"); u->dump(); });
2193 DEBUG_ONLY(if (trace && m != nullptr) { tty->print("ZZZ mem"); m->dump(); });
2194
2195 if (!mem_is_valid(m, u) || !m->is_Phi()) {
2196 bool push = true;
2197 bool create_phi = true;
2198 if (_phase->is_dominator(new_ctrl, u)) {
2199 create_phi = false;
2200 }
2201 if (create_phi) {
2202 Node* phi = new PhiNode(u, Type::MEMORY, _phase->C->get_adr_type(_alias));
2203 _phase->register_new_node(phi, u);
2204 phis.push(phi);
2205 DEBUG_ONLY(if (trace) { tty->print("ZZZ new phi"); phi->dump(); });
2206 if (!mem_is_valid(m, u)) {
2207 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting mem"); phi->dump(); });
2208 _memory_nodes.map(u->_idx, phi);
2209 } else {
2210 DEBUG_ONLY(if (trace) { tty->print("ZZZ NOT setting mem"); m->dump(); });
2211 for (;;) {
2212 assert(m->is_Mem() || m->is_LoadStore() || m->is_Proj(), "");
2213 Node* next = nullptr;
2214 if (m->is_Proj()) {
2215 next = m->in(0);
2216 } else {
2217 assert(m->is_Mem() || m->is_LoadStore(), "");
2218 assert(_alias == Compile::AliasIdxRaw, "");
2219 next = m->in(MemNode::Memory);
2220 }
2221 if (_phase->get_ctrl(next) != u) {
2222 break;
2223 }
2224 if (next->is_MergeMem()) {
2225 assert(_phase->get_ctrl(next->as_MergeMem()->memory_at(_alias)) != u, "");
2226 break;
2227 }
2228 if (next->is_Phi()) {
2229 assert(next->adr_type() == TypePtr::BOTTOM && next->in(0) == u, "");
2230 break;
2231 }
2232 m = next;
2233 }
2234
2235 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting to phi"); m->dump(); });
2236 assert(m->is_Mem() || m->is_LoadStore(), "");
2237 uint input = (uint)MemNode::Memory;
2238 _phase->igvn().replace_input_of(m, input, phi);
2239 push = false;
2240 }
2241 } else {
2242 DEBUG_ONLY(if (trace) { tty->print("ZZZ skipping region"); u->dump(); });
2243 }
2244 if (push) {
2245 uses.push(u);
2246 }
2247 }
2248 } else if (!mem_is_valid(m, u) &&
2249 !(u->Opcode() == Op_CProj && u->in(0)->is_NeverBranch() && u->as_Proj()->_con == 1)) {
2250 uses.push(u);
2251 }
2252 }
2253 }
2254 }
2255 for (int i = 0; i < phis.length(); i++) {
2256 Node* n = phis.at(i);
2257 Node* r = n->in(0);
2258 DEBUG_ONLY(if (trace) { tty->print("ZZZ fixing new phi"); n->dump(); });
2259 for (uint j = 1; j < n->req(); j++) {
2260 Node* m = find_mem(r->in(j), nullptr);
2261 _phase->igvn().replace_input_of(n, j, m);
2262 DEBUG_ONLY(if (trace) { tty->print("ZZZ fixing new phi: %d", j); m->dump(); });
2263 }
2264 }
2265 }
2266 uint last = _phase->C->unique();
2267 MergeMemNode* mm = nullptr;
2268 int alias = _alias;
2269 DEBUG_ONLY(if (trace) { tty->print("ZZZ raw mem is"); mem->dump(); });
2270 // Process loads first to not miss an anti-dependency: if the memory
2271 // edge of a store is updated before a load is processed then an
2272 // anti-dependency may be missed.
2273 for (DUIterator i = mem->outs(); mem->has_out(i); i++) {
2274 Node* u = mem->out(i);
2275 if (u->_idx < last && u->is_Load() && _phase->C->get_alias_index(u->adr_type()) == alias) {
2276 Node* m = find_mem(_phase->get_ctrl(u), u);
2277 if (m != mem) {
2278 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of use"); u->dump(); });
2279 _phase->igvn().replace_input_of(u, MemNode::Memory, m);
2280 --i;
2281 }
2282 }
2283 }
2284 for (DUIterator i = mem->outs(); mem->has_out(i); i++) {
2285 Node* u = mem->out(i);
2286 if (u->_idx < last) {
2287 if (u->is_Mem()) {
2288 if (_phase->C->get_alias_index(u->adr_type()) == alias) {
2289 Node* m = find_mem(_phase->get_ctrl(u), u);
2290 if (m != mem) {
2291 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of use"); u->dump(); });
2292 _phase->igvn().replace_input_of(u, MemNode::Memory, m);
2293 --i;
2294 }
2295 }
2296 } else if (u->is_MergeMem()) {
2297 MergeMemNode* u_mm = u->as_MergeMem();
2298 if (u_mm->memory_at(alias) == mem) {
2299 MergeMemNode* newmm = nullptr;
2300 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) {
2301 Node* uu = u->fast_out(j);
2302 assert(!uu->is_MergeMem(), "chain of MergeMems?");
2303 if (uu->is_Phi()) {
2304 assert(uu->adr_type() == TypePtr::BOTTOM, "");
2305 Node* region = uu->in(0);
2306 int nb = 0;
2307 for (uint k = 1; k < uu->req(); k++) {
2308 if (uu->in(k) == u) {
2309 Node* m = find_mem(region->in(k), nullptr);
2310 if (m != mem) {
2311 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of phi %d", k); uu->dump(); });
2312 newmm = clone_merge_mem(u, mem, m, _phase->ctrl_or_self(m), i);
2313 if (newmm != u) {
2314 _phase->igvn().replace_input_of(uu, k, newmm);
2315 nb++;
2316 --jmax;
2317 }
2318 }
2319 }
2320 }
2321 if (nb > 0) {
2322 --j;
2323 }
2324 } else {
2325 Node* m = find_mem(_phase->ctrl_or_self(uu), uu);
2326 if (m != mem) {
2327 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of use"); uu->dump(); });
2328 newmm = clone_merge_mem(u, mem, m, _phase->ctrl_or_self(m), i);
2329 if (newmm != u) {
2330 _phase->igvn().replace_input_of(uu, uu->find_edge(u), newmm);
2331 --j, --jmax;
2332 }
2333 }
2334 }
2335 }
2336 }
2337 } else if (u->is_Phi()) {
2338 assert(u->bottom_type() == Type::MEMORY, "what else?");
2339 if (_phase->C->get_alias_index(u->adr_type()) == alias || u->adr_type() == TypePtr::BOTTOM) {
2340 Node* region = u->in(0);
2341 bool replaced = false;
2342 for (uint j = 1; j < u->req(); j++) {
2343 if (u->in(j) == mem) {
2344 Node* m = find_mem(region->in(j), nullptr);
2345 Node* nnew = m;
2346 if (m != mem) {
2347 if (u->adr_type() == TypePtr::BOTTOM) {
2348 mm = allocate_merge_mem(mem, m, _phase->ctrl_or_self(m));
2349 nnew = mm;
2350 }
2351 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of phi %d", j); u->dump(); });
2352 _phase->igvn().replace_input_of(u, j, nnew);
2353 replaced = true;
2354 }
2355 }
2356 }
2357 if (replaced) {
2358 --i;
2359 }
2360 }
2361 } else if ((u->adr_type() == TypePtr::BOTTOM && u->Opcode() != Op_StrInflatedCopy) ||
2362 u->adr_type() == nullptr) {
2363 assert(u->adr_type() != nullptr ||
2364 u->Opcode() == Op_Rethrow ||
2365 u->Opcode() == Op_Return ||
2366 u->Opcode() == Op_SafePoint ||
2367 (u->is_CallStaticJava() && u->as_CallStaticJava()->uncommon_trap_request() != 0) ||
2368 (u->is_CallStaticJava() && u->as_CallStaticJava()->_entry_point == OptoRuntime::rethrow_stub()) ||
2369 u->Opcode() == Op_CallLeaf, "");
2370 Node* m = find_mem(_phase->ctrl_or_self(u), u);
2371 if (m != mem) {
2372 mm = allocate_merge_mem(mem, m, _phase->get_ctrl(m));
2373 _phase->igvn().replace_input_of(u, u->find_edge(mem), mm);
2374 --i;
2375 }
2376 } else if (_phase->C->get_alias_index(u->adr_type()) == alias) {
2377 Node* m = find_mem(_phase->ctrl_or_self(u), u);
2378 if (m != mem) {
2379 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of use"); u->dump(); });
2380 _phase->igvn().replace_input_of(u, u->find_edge(mem), m);
2381 --i;
2382 }
2383 } else if (u->adr_type() != TypePtr::BOTTOM &&
2384 _memory_nodes[_phase->ctrl_or_self(u)->_idx] == u) {
2385 Node* m = find_mem(_phase->ctrl_or_self(u), u);
2386 assert(m != mem, "");
2387 // u is on the wrong slice...
2388 assert(u->is_ClearArray(), "");
2389 DEBUG_ONLY(if (trace) { tty->print("ZZZ setting memory of use"); u->dump(); });
2390 _phase->igvn().replace_input_of(u, u->find_edge(mem), m);
2391 --i;
2392 }
2393 }
2394 }
2395 #ifdef ASSERT
2396 assert(new_mem->outcnt() > 0, "");
2397 for (int i = 0; i < phis.length(); i++) {
2398 Node* n = phis.at(i);
2399 assert(n->outcnt() > 0, "new phi must have uses now");
2400 }
2401 #endif
2402 }
2403
2404 void MemoryGraphFixer::record_new_ctrl(Node* ctrl, Node* new_ctrl, Node* mem, Node* mem_for_ctrl) {
2405 if (mem_for_ctrl != mem && new_ctrl != ctrl) {
2406 _memory_nodes.map(ctrl->_idx, mem);
2407 _memory_nodes.map(new_ctrl->_idx, mem_for_ctrl);
2408 }
2409 }
2410
2411 MergeMemNode* MemoryGraphFixer::allocate_merge_mem(Node* mem, Node* rep_proj, Node* rep_ctrl) const {
2412 MergeMemNode* mm = MergeMemNode::make(mem);
2413 mm->set_memory_at(_alias, rep_proj);
2414 _phase->register_new_node(mm, rep_ctrl);
2415 return mm;
2416 }
2417
2418 MergeMemNode* MemoryGraphFixer::clone_merge_mem(Node* u, Node* mem, Node* rep_proj, Node* rep_ctrl, DUIterator& i) const {
2419 MergeMemNode* newmm = nullptr;
2420 MergeMemNode* u_mm = u->as_MergeMem();
2421 Node* c = _phase->get_ctrl(u);
2422 if (_phase->is_dominator(c, rep_ctrl)) {
2423 c = rep_ctrl;
2424 } else {
2425 assert(_phase->is_dominator(rep_ctrl, c), "one must dominate the other");
2426 }
2427 if (u->outcnt() == 1) {
2428 if (u->req() > (uint)_alias && u->in(_alias) == mem) {
2429 _phase->igvn().replace_input_of(u, _alias, rep_proj);
2430 --i;
2431 } else {
2432 _phase->igvn().rehash_node_delayed(u);
2433 u_mm->set_memory_at(_alias, rep_proj);
2434 }
2435 newmm = u_mm;
2436 _phase->set_ctrl_and_loop(u, c);
2437 } else {
2438 // can't simply clone u and then change one of its input because
2439 // it adds and then removes an edge which messes with the
2440 // DUIterator
2441 newmm = MergeMemNode::make(u_mm->base_memory());
2442 for (uint j = 0; j < u->req(); j++) {
2443 if (j < newmm->req()) {
2444 if (j == (uint)_alias) {
2445 newmm->set_req(j, rep_proj);
2446 } else if (newmm->in(j) != u->in(j)) {
2447 newmm->set_req(j, u->in(j));
2448 }
2449 } else if (j == (uint)_alias) {
2450 newmm->add_req(rep_proj);
2451 } else {
2452 newmm->add_req(u->in(j));
2453 }
2454 }
2455 if ((uint)_alias >= u->req()) {
2456 newmm->set_memory_at(_alias, rep_proj);
2457 }
2458 _phase->register_new_node(newmm, c);
2459 }
2460 return newmm;
2461 }
2462
2463 bool MemoryGraphFixer::should_process_phi(Node* phi) const {
2464 if (phi->adr_type() == TypePtr::BOTTOM) {
2465 Node* region = phi->in(0);
2466 for (DUIterator_Fast jmax, j = region->fast_outs(jmax); j < jmax; j++) {
2467 Node* uu = region->fast_out(j);
2468 if (uu->is_Phi() && uu != phi && uu->bottom_type() == Type::MEMORY && _phase->C->get_alias_index(uu->adr_type()) == _alias) {
2469 return false;
2470 }
2471 }
2472 return true;
2473 }
2474 return _phase->C->get_alias_index(phi->adr_type()) == _alias;
2475 }
2476
2477 void MemoryGraphFixer::fix_memory_uses(Node* mem, Node* replacement, Node* rep_proj, Node* rep_ctrl) const {
2478 uint last = _phase-> C->unique();
2479 MergeMemNode* mm = nullptr;
2480 assert(mem->bottom_type() == Type::MEMORY, "");
2481 for (DUIterator i = mem->outs(); mem->has_out(i); i++) {
2482 Node* u = mem->out(i);
2483 if (u != replacement && u->_idx < last) {
2484 if (u->is_MergeMem()) {
2485 MergeMemNode* u_mm = u->as_MergeMem();
2486 if (u_mm->memory_at(_alias) == mem) {
2487 MergeMemNode* newmm = nullptr;
2488 for (DUIterator_Fast jmax, j = u->fast_outs(jmax); j < jmax; j++) {
2489 Node* uu = u->fast_out(j);
2490 assert(!uu->is_MergeMem(), "chain of MergeMems?");
2491 if (uu->is_Phi()) {
2492 if (should_process_phi(uu)) {
2493 Node* region = uu->in(0);
2494 int nb = 0;
2495 for (uint k = 1; k < uu->req(); k++) {
2496 if (uu->in(k) == u && _phase->is_dominator(rep_ctrl, region->in(k))) {
2497 if (newmm == nullptr) {
2498 newmm = clone_merge_mem(u, mem, rep_proj, rep_ctrl, i);
2499 }
2500 if (newmm != u) {
2501 _phase->igvn().replace_input_of(uu, k, newmm);
2502 nb++;
2503 --jmax;
2504 }
2505 }
2506 }
2507 if (nb > 0) {
2508 --j;
2509 }
2510 }
2511 } else {
2512 if (rep_ctrl != uu && ShenandoahBarrierC2Support::is_dominator(rep_ctrl, _phase->ctrl_or_self(uu), replacement, uu, _phase)) {
2513 if (newmm == nullptr) {
2514 newmm = clone_merge_mem(u, mem, rep_proj, rep_ctrl, i);
2515 }
2516 if (newmm != u) {
2517 _phase->igvn().replace_input_of(uu, uu->find_edge(u), newmm);
2518 --j, --jmax;
2519 }
2520 }
2521 }
2522 }
2523 }
2524 } else if (u->is_Phi()) {
2525 assert(u->bottom_type() == Type::MEMORY, "what else?");
2526 Node* region = u->in(0);
2527 if (should_process_phi(u)) {
2528 bool replaced = false;
2529 for (uint j = 1; j < u->req(); j++) {
2530 if (u->in(j) == mem && _phase->is_dominator(rep_ctrl, region->in(j))) {
2531 Node* nnew = rep_proj;
2532 if (u->adr_type() == TypePtr::BOTTOM) {
2533 if (mm == nullptr) {
2534 mm = allocate_merge_mem(mem, rep_proj, rep_ctrl);
2535 }
2536 nnew = mm;
2537 }
2538 _phase->igvn().replace_input_of(u, j, nnew);
2539 replaced = true;
2540 }
2541 }
2542 if (replaced) {
2543 --i;
2544 }
2545
2546 }
2547 } else if ((u->adr_type() == TypePtr::BOTTOM && u->Opcode() != Op_StrInflatedCopy) ||
2548 u->adr_type() == nullptr) {
2549 assert(u->adr_type() != nullptr ||
2550 u->Opcode() == Op_Rethrow ||
2551 u->Opcode() == Op_Return ||
2552 u->Opcode() == Op_SafePoint ||
2553 (u->is_CallStaticJava() && u->as_CallStaticJava()->uncommon_trap_request() != 0) ||
2554 (u->is_CallStaticJava() && u->as_CallStaticJava()->_entry_point == OptoRuntime::rethrow_stub()) ||
2555 u->Opcode() == Op_CallLeaf, "%s", u->Name());
2556 if (ShenandoahBarrierC2Support::is_dominator(rep_ctrl, _phase->ctrl_or_self(u), replacement, u, _phase)) {
2557 if (mm == nullptr) {
2558 mm = allocate_merge_mem(mem, rep_proj, rep_ctrl);
2559 }
2560 _phase->igvn().replace_input_of(u, u->find_edge(mem), mm);
2561 --i;
2562 }
2563 } else if (_phase->C->get_alias_index(u->adr_type()) == _alias) {
2564 if (ShenandoahBarrierC2Support::is_dominator(rep_ctrl, _phase->ctrl_or_self(u), replacement, u, _phase)) {
2565 _phase->igvn().replace_input_of(u, u->find_edge(mem), rep_proj);
2566 --i;
2567 }
2568 }
2569 }
2570 }
2571 }
2572
2573 ShenandoahLoadReferenceBarrierNode::ShenandoahLoadReferenceBarrierNode(Node* ctrl, Node* obj, DecoratorSet decorators)
2574 : Node(ctrl, obj), _decorators(decorators) {
2575 ShenandoahBarrierSetC2::bsc2()->state()->add_load_reference_barrier(this);
2576 }
2577
2578 DecoratorSet ShenandoahLoadReferenceBarrierNode::decorators() const {
2579 return _decorators;
2580 }
2581
2582 uint ShenandoahLoadReferenceBarrierNode::size_of() const {
2583 return sizeof(*this);
2584 }
2585
2586 static DecoratorSet mask_decorators(DecoratorSet decorators) {
2587 return decorators & (ON_STRONG_OOP_REF | ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF | ON_UNKNOWN_OOP_REF | IN_NATIVE);
2588 }
2589
2590 uint ShenandoahLoadReferenceBarrierNode::hash() const {
2591 uint hash = Node::hash();
2592 hash += mask_decorators(_decorators);
2593 return hash;
2594 }
2595
2596 bool ShenandoahLoadReferenceBarrierNode::cmp( const Node &n ) const {
2597 return Node::cmp(n) && n.Opcode() == Op_ShenandoahLoadReferenceBarrier &&
2598 mask_decorators(_decorators) == mask_decorators(((const ShenandoahLoadReferenceBarrierNode&)n)._decorators);
2599 }
2600
2601 const Type* ShenandoahLoadReferenceBarrierNode::bottom_type() const {
2602 if (in(ValueIn) == nullptr || in(ValueIn)->is_top()) {
2603 return Type::TOP;
2604 }
2605 const Type* t = in(ValueIn)->bottom_type();
2606 if (t == TypePtr::NULL_PTR) {
2607 return t;
2608 }
2609
2610 if (ShenandoahBarrierSet::is_strong_access(decorators())) {
2611 return t;
2612 }
2613
2614 return t->meet(TypePtr::NULL_PTR);
2615 }
2616
2617 const Type* ShenandoahLoadReferenceBarrierNode::Value(PhaseGVN* phase) const {
2618 // Either input is TOP ==> the result is TOP
2619 const Type *t2 = phase->type(in(ValueIn));
2620 if( t2 == Type::TOP ) return Type::TOP;
2621
2622 if (t2 == TypePtr::NULL_PTR) {
2623 return t2;
2624 }
2625
2626 if (ShenandoahBarrierSet::is_strong_access(decorators())) {
2627 return t2;
2628 }
2629
2630 return t2->meet(TypePtr::NULL_PTR);
2631 }
2632
2633 Node* ShenandoahLoadReferenceBarrierNode::Identity(PhaseGVN* phase) {
2634 Node* value = in(ValueIn);
2635 if (!needs_barrier(phase, value)) {
2636 return value;
2637 }
2638 return this;
2639 }
2640
2641 bool ShenandoahLoadReferenceBarrierNode::needs_barrier(PhaseGVN* phase, Node* n) {
2642 Unique_Node_List visited;
2643 return needs_barrier_impl(phase, n, visited);
2644 }
2645
2646 bool ShenandoahLoadReferenceBarrierNode::needs_barrier_impl(PhaseGVN* phase, Node* n, Unique_Node_List &visited) {
2647 if (n == nullptr) return false;
2648 if (visited.member(n)) {
2649 return false; // Been there.
2650 }
2651 visited.push(n);
2652
2653 if (n->is_Allocate()) {
2654 // tty->print_cr("optimize barrier on alloc");
2655 return false;
2656 }
2657 if (n->is_Call()) {
2658 // tty->print_cr("optimize barrier on call");
2659 return false;
2660 }
2661
2662 const Type* type = phase->type(n);
2663 if (type == Type::TOP) {
2664 return false;
2665 }
2666 if (type->make_ptr()->higher_equal(TypePtr::NULL_PTR)) {
2667 // tty->print_cr("optimize barrier on null");
2668 return false;
2669 }
2670 if (type->make_oopptr() && type->make_oopptr()->const_oop() != nullptr) {
2671 // tty->print_cr("optimize barrier on constant");
2672 return false;
2673 }
2674
2675 switch (n->Opcode()) {
2676 case Op_AddP:
2677 return true; // TODO: Can refine?
2678 case Op_LoadP:
2679 case Op_ShenandoahCompareAndExchangeN:
2680 case Op_ShenandoahCompareAndExchangeP:
2681 case Op_CompareAndExchangeN:
2682 case Op_CompareAndExchangeP:
2683 case Op_GetAndSetN:
2684 case Op_GetAndSetP:
2685 return true;
2686 case Op_Phi: {
2687 for (uint i = 1; i < n->req(); i++) {
2688 if (needs_barrier_impl(phase, n->in(i), visited)) return true;
2689 }
2690 return false;
2691 }
2692 case Op_CheckCastPP:
2693 case Op_CastPP:
2694 return needs_barrier_impl(phase, n->in(1), visited);
2695 case Op_Proj:
2696 return needs_barrier_impl(phase, n->in(0), visited);
2697 case Op_ShenandoahLoadReferenceBarrier:
2698 // tty->print_cr("optimize barrier on barrier");
2699 return false;
2700 case Op_Parm:
2701 // tty->print_cr("optimize barrier on input arg");
2702 return false;
2703 case Op_DecodeN:
2704 case Op_EncodeP:
2705 return needs_barrier_impl(phase, n->in(1), visited);
2706 case Op_LoadN:
2707 return true;
2708 case Op_CMoveN:
2709 case Op_CMoveP:
2710 return needs_barrier_impl(phase, n->in(2), visited) ||
2711 needs_barrier_impl(phase, n->in(3), visited);
2712 case Op_CreateEx:
2713 return false;
2714 default:
2715 break;
2716 }
2717 #ifdef ASSERT
2718 tty->print("need barrier on?: ");
2719 tty->print_cr("ins:");
2720 n->dump(2);
2721 tty->print_cr("outs:");
2722 n->dump(-2);
2723 ShouldNotReachHere();
2724 #endif
2725 return true;
2726 }