1 /*
2 * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 #include "precompiled.hpp"
25 #include "classfile/javaClasses.hpp"
26 #include "gc/z/c2/zBarrierSetC2.hpp"
27 #include "gc/z/zBarrierSet.hpp"
28 #include "gc/z/zBarrierSetAssembler.hpp"
29 #include "gc/z/zBarrierSetRuntime.hpp"
30 #include "opto/arraycopynode.hpp"
31 #include "opto/addnode.hpp"
32 #include "opto/block.hpp"
33 #include "opto/compile.hpp"
34 #include "opto/graphKit.hpp"
35 #include "opto/machnode.hpp"
36 #include "opto/macro.hpp"
37 #include "opto/memnode.hpp"
38 #include "opto/node.hpp"
39 #include "opto/output.hpp"
40 #include "opto/regalloc.hpp"
41 #include "opto/rootnode.hpp"
42 #include "opto/runtime.hpp"
43 #include "opto/type.hpp"
44 #include "utilities/growableArray.hpp"
45 #include "utilities/macros.hpp"
46
47 class ZBarrierSetC2State : public ResourceObj {
48 private:
49 GrowableArray<ZLoadBarrierStubC2*>* _stubs;
50 Node_Array _live;
51
52 public:
53 ZBarrierSetC2State(Arena* arena) :
54 _stubs(new (arena) GrowableArray<ZLoadBarrierStubC2*>(arena, 8, 0, NULL)),
55 _live(arena) {}
56
57 GrowableArray<ZLoadBarrierStubC2*>* stubs() {
58 return _stubs;
59 }
60
61 RegMask* live(const Node* node) {
62 if (!node->is_Mach()) {
63 // Don't need liveness for non-MachNodes
64 return NULL;
65 }
66
67 const MachNode* const mach = node->as_Mach();
68 if (mach->barrier_data() == ZLoadBarrierElided) {
69 // Don't need liveness data for nodes without barriers
70 return NULL;
71 }
72
73 RegMask* live = (RegMask*)_live[node->_idx];
74 if (live == NULL) {
75 live = new (Compile::current()->comp_arena()->Amalloc_D(sizeof(RegMask))) RegMask();
76 _live.map(node->_idx, (Node*)live);
77 }
78
79 return live;
80 }
81 };
82
83 static ZBarrierSetC2State* barrier_set_state() {
84 return reinterpret_cast<ZBarrierSetC2State*>(Compile::current()->barrier_set_state());
85 }
86
87 ZLoadBarrierStubC2* ZLoadBarrierStubC2::create(const MachNode* node, Address ref_addr, Register ref, Register tmp, uint8_t barrier_data) {
88 ZLoadBarrierStubC2* const stub = new (Compile::current()->comp_arena()) ZLoadBarrierStubC2(node, ref_addr, ref, tmp, barrier_data);
89 if (!Compile::current()->output()->in_scratch_emit_size()) {
90 barrier_set_state()->stubs()->append(stub);
91 }
92
93 return stub;
94 }
95
96 ZLoadBarrierStubC2::ZLoadBarrierStubC2(const MachNode* node, Address ref_addr, Register ref, Register tmp, uint8_t barrier_data) :
97 _node(node),
98 _ref_addr(ref_addr),
99 _ref(ref),
100 _tmp(tmp),
101 _barrier_data(barrier_data),
102 _entry(),
103 _continuation() {
104 assert_different_registers(ref, ref_addr.base());
105 assert_different_registers(ref, ref_addr.index());
106 }
107
108 Address ZLoadBarrierStubC2::ref_addr() const {
109 return _ref_addr;
110 }
111
112 Register ZLoadBarrierStubC2::ref() const {
113 return _ref;
114 }
115
116 Register ZLoadBarrierStubC2::tmp() const {
117 return _tmp;
118 }
119
120 address ZLoadBarrierStubC2::slow_path() const {
121 DecoratorSet decorators = DECORATORS_NONE;
122 if (_barrier_data & ZLoadBarrierStrong) {
123 decorators |= ON_STRONG_OOP_REF;
124 }
125 if (_barrier_data & ZLoadBarrierWeak) {
126 decorators |= ON_WEAK_OOP_REF;
127 }
128 if (_barrier_data & ZLoadBarrierPhantom) {
129 decorators |= ON_PHANTOM_OOP_REF;
130 }
131 if (_barrier_data & ZLoadBarrierNoKeepalive) {
132 decorators |= AS_NO_KEEPALIVE;
133 }
134 return ZBarrierSetRuntime::load_barrier_on_oop_field_preloaded_addr(decorators);
135 }
136
137 RegMask& ZLoadBarrierStubC2::live() const {
138 return *barrier_set_state()->live(_node);
139 }
140
141 Label* ZLoadBarrierStubC2::entry() {
142 // The _entry will never be bound when in_scratch_emit_size() is true.
143 // However, we still need to return a label that is not bound now, but
144 // will eventually be bound. Any lable will do, as it will only act as
145 // a placeholder, so we return the _continuation label.
146 return Compile::current()->output()->in_scratch_emit_size() ? &_continuation : &_entry;
147 }
148
149 Label* ZLoadBarrierStubC2::continuation() {
150 return &_continuation;
151 }
152
153 void* ZBarrierSetC2::create_barrier_state(Arena* comp_arena) const {
154 return new (comp_arena) ZBarrierSetC2State(comp_arena);
155 }
156
157 void ZBarrierSetC2::late_barrier_analysis() const {
158 analyze_dominating_barriers();
159 compute_liveness_at_stubs();
160 }
161
162 void ZBarrierSetC2::emit_stubs(CodeBuffer& cb) const {
163 MacroAssembler masm(&cb);
164 GrowableArray<ZLoadBarrierStubC2*>* const stubs = barrier_set_state()->stubs();
165
166 for (int i = 0; i < stubs->length(); i++) {
167 // Make sure there is enough space in the code buffer
168 if (cb.insts()->maybe_expand_to_ensure_remaining(PhaseOutput::MAX_inst_size) && cb.blob() == NULL) {
169 ciEnv::current()->record_failure("CodeCache is full");
170 return;
171 }
172
173 ZBarrierSet::assembler()->generate_c2_load_barrier_stub(&masm, stubs->at(i));
174 }
175
176 masm.flush();
177 }
178
179 int ZBarrierSetC2::estimate_stub_size() const {
180 Compile* const C = Compile::current();
181 BufferBlob* const blob = C->output()->scratch_buffer_blob();
182 GrowableArray<ZLoadBarrierStubC2*>* const stubs = barrier_set_state()->stubs();
183 int size = 0;
184
185 for (int i = 0; i < stubs->length(); i++) {
186 CodeBuffer cb(blob->content_begin(), (address)C->output()->scratch_locs_memory() - blob->content_begin());
187 MacroAssembler masm(&cb);
188 ZBarrierSet::assembler()->generate_c2_load_barrier_stub(&masm, stubs->at(i));
189 size += cb.insts_size();
190 }
191
192 return size;
193 }
194
195 static void set_barrier_data(C2Access& access) {
196 if (ZBarrierSet::barrier_needed(access.decorators(), access.type())) {
197 uint8_t barrier_data = 0;
198
199 if (access.decorators() & ON_PHANTOM_OOP_REF) {
200 barrier_data |= ZLoadBarrierPhantom;
201 } else if (access.decorators() & ON_WEAK_OOP_REF) {
202 barrier_data |= ZLoadBarrierWeak;
203 } else {
204 barrier_data |= ZLoadBarrierStrong;
205 }
206
207 if (access.decorators() & AS_NO_KEEPALIVE) {
208 barrier_data |= ZLoadBarrierNoKeepalive;
209 }
210
211 access.set_barrier_data(barrier_data);
212 }
213 }
214
215 Node* ZBarrierSetC2::load_at_resolved(C2Access& access, const Type* val_type) const {
216 set_barrier_data(access);
217 return BarrierSetC2::load_at_resolved(access, val_type);
218 }
219
220 Node* ZBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
221 Node* new_val, const Type* val_type) const {
222 set_barrier_data(access);
223 return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, val_type);
224 }
225
226 Node* ZBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
227 Node* new_val, const Type* value_type) const {
228 set_barrier_data(access);
229 return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
230 }
231
232 Node* ZBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* val_type) const {
233 set_barrier_data(access);
234 return BarrierSetC2::atomic_xchg_at_resolved(access, new_val, val_type);
235 }
236
237 bool ZBarrierSetC2::array_copy_requires_gc_barriers(bool tightly_coupled_alloc, BasicType type,
238 bool is_clone, bool is_clone_instance,
239 ArrayCopyPhase phase) const {
240 if (phase == ArrayCopyPhase::Parsing) {
241 return false;
242 }
243 if (phase == ArrayCopyPhase::Optimization) {
244 return is_clone_instance;
245 }
246 // else ArrayCopyPhase::Expansion
247 return type == T_OBJECT || type == T_ARRAY;
248 }
249
250 // This TypeFunc assumes a 64bit system
251 static const TypeFunc* clone_type() {
252 // Create input type (domain)
253 const Type** domain_fields = TypeTuple::fields(4);
254 domain_fields[TypeFunc::Parms + 0] = TypeInstPtr::NOTNULL; // src
255 domain_fields[TypeFunc::Parms + 1] = TypeInstPtr::NOTNULL; // dst
256 domain_fields[TypeFunc::Parms + 2] = TypeLong::LONG; // size lower
257 domain_fields[TypeFunc::Parms + 3] = Type::HALF; // size upper
258 const TypeTuple* domain = TypeTuple::make(TypeFunc::Parms + 4, domain_fields);
259
260 // Create result type (range)
261 const Type** range_fields = TypeTuple::fields(0);
262 const TypeTuple* range = TypeTuple::make(TypeFunc::Parms + 0, range_fields);
263
264 return TypeFunc::make(domain, range);
265 }
266
267 #define XTOP LP64_ONLY(COMMA phase->top())
268
269 void ZBarrierSetC2::clone_at_expansion(PhaseMacroExpand* phase, ArrayCopyNode* ac) const {
270 Node* const src = ac->in(ArrayCopyNode::Src);
271 const TypeAryPtr* ary_ptr = src->get_ptr_type()->isa_aryptr();
272
273 if (ac->is_clone_array() && ary_ptr != NULL) {
274 BasicType bt = ary_ptr->elem()->array_element_basic_type();
275 if (is_reference_type(bt)) {
276 // Clone object array
277 bt = T_OBJECT;
278 } else {
279 // Clone primitive array
280 bt = T_LONG;
281 }
282
283 Node* ctrl = ac->in(TypeFunc::Control);
284 Node* mem = ac->in(TypeFunc::Memory);
285 Node* src = ac->in(ArrayCopyNode::Src);
286 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
287 Node* dest = ac->in(ArrayCopyNode::Dest);
288 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
289 Node* length = ac->in(ArrayCopyNode::Length);
290
291 if (bt == T_OBJECT) {
292 // BarrierSetC2::clone sets the offsets via BarrierSetC2::arraycopy_payload_base_offset
293 // which 8-byte aligns them to allow for word size copies. Make sure the offsets point
294 // to the first element in the array when cloning object arrays. Otherwise, load
295 // barriers are applied to parts of the header. Also adjust the length accordingly.
296 assert(src_offset == dest_offset, "should be equal");
297 jlong offset = src_offset->get_long();
298 if (offset != arrayOopDesc::base_offset_in_bytes(T_OBJECT)) {
299 assert(!UseCompressedClassPointers || UseCompactObjectHeaders, "should only happen without compressed class pointers or with compact object headers");
300 assert((arrayOopDesc::base_offset_in_bytes(T_OBJECT) - offset) == BytesPerLong, "unexpected offset");
301 length = phase->transform_later(new SubLNode(length, phase->longcon(1))); // Size is in longs
302 src_offset = phase->longcon(arrayOopDesc::base_offset_in_bytes(T_OBJECT));
303 dest_offset = src_offset;
304 }
305 }
306 Node* payload_src = phase->basic_plus_adr(src, src_offset);
307 Node* payload_dst = phase->basic_plus_adr(dest, dest_offset);
308
309 const char* copyfunc_name = "arraycopy";
310 address copyfunc_addr = phase->basictype2arraycopy(bt, NULL, NULL, true, copyfunc_name, true);
311
312 const TypePtr* raw_adr_type = TypeRawPtr::BOTTOM;
313 const TypeFunc* call_type = OptoRuntime::fast_arraycopy_Type();
314
315 Node* call = phase->make_leaf_call(ctrl, mem, call_type, copyfunc_addr, copyfunc_name, raw_adr_type, payload_src, payload_dst, length XTOP);
316 phase->transform_later(call);
317
318 phase->igvn().replace_node(ac, call);
319 return;
320 }
321
322 // Clone instance
323 Node* const ctrl = ac->in(TypeFunc::Control);
324 Node* const mem = ac->in(TypeFunc::Memory);
325 Node* const dst = ac->in(ArrayCopyNode::Dest);
326 Node* const size = ac->in(ArrayCopyNode::Length);
327
328 assert(size->bottom_type()->is_long(), "Should be long");
329
330 // The native clone we are calling here expects the instance size in words
331 // Add header/offset size to payload size to get instance size.
332 Node* const base_offset = phase->longcon(arraycopy_payload_base_offset(ac->is_clone_array()) >> LogBytesPerLong);
333 Node* const full_size = phase->transform_later(new AddLNode(size, base_offset));
334
335 Node* const call = phase->make_leaf_call(ctrl,
336 mem,
337 clone_type(),
338 ZBarrierSetRuntime::clone_addr(),
339 "ZBarrierSetRuntime::clone",
340 TypeRawPtr::BOTTOM,
341 src,
342 dst,
343 full_size,
344 phase->top());
345 phase->transform_later(call);
346 phase->igvn().replace_node(ac, call);
347 }
348
349 #undef XTOP
350
351 // == Dominating barrier elision ==
352
353 static bool block_has_safepoint(const Block* block, uint from, uint to) {
354 for (uint i = from; i < to; i++) {
355 if (block->get_node(i)->is_MachSafePoint()) {
356 // Safepoint found
357 return true;
358 }
359 }
360
361 // Safepoint not found
362 return false;
363 }
364
365 static bool block_has_safepoint(const Block* block) {
366 return block_has_safepoint(block, 0, block->number_of_nodes());
367 }
368
369 static uint block_index(const Block* block, const Node* node) {
370 for (uint j = 0; j < block->number_of_nodes(); ++j) {
371 if (block->get_node(j) == node) {
372 return j;
373 }
374 }
375 ShouldNotReachHere();
376 return 0;
377 }
378
379 void ZBarrierSetC2::analyze_dominating_barriers() const {
380 ResourceMark rm;
381 Compile* const C = Compile::current();
382 PhaseCFG* const cfg = C->cfg();
383 Block_List worklist;
384 Node_List mem_ops;
385 Node_List barrier_loads;
386
387 // Step 1 - Find accesses, and track them in lists
388 for (uint i = 0; i < cfg->number_of_blocks(); ++i) {
389 const Block* const block = cfg->get_block(i);
390 for (uint j = 0; j < block->number_of_nodes(); ++j) {
391 const Node* const node = block->get_node(j);
392 if (!node->is_Mach()) {
393 continue;
394 }
395
396 MachNode* const mach = node->as_Mach();
397 switch (mach->ideal_Opcode()) {
398 case Op_LoadP:
399 if ((mach->barrier_data() & ZLoadBarrierStrong) != 0) {
400 barrier_loads.push(mach);
401 }
402 if ((mach->barrier_data() & (ZLoadBarrierStrong | ZLoadBarrierNoKeepalive)) ==
403 ZLoadBarrierStrong) {
404 mem_ops.push(mach);
405 }
406 break;
407 case Op_CompareAndExchangeP:
408 case Op_CompareAndSwapP:
409 case Op_GetAndSetP:
410 if ((mach->barrier_data() & ZLoadBarrierStrong) != 0) {
411 barrier_loads.push(mach);
412 }
413 case Op_StoreP:
414 mem_ops.push(mach);
415 break;
416
417 default:
418 break;
419 }
420 }
421 }
422
423 // Step 2 - Find dominating accesses for each load
424 for (uint i = 0; i < barrier_loads.size(); i++) {
425 MachNode* const load = barrier_loads.at(i)->as_Mach();
426 const TypePtr* load_adr_type = NULL;
427 intptr_t load_offset = 0;
428 const Node* const load_obj = load->get_base_and_disp(load_offset, load_adr_type);
429 Block* const load_block = cfg->get_block_for_node(load);
430 const uint load_index = block_index(load_block, load);
431
432 for (uint j = 0; j < mem_ops.size(); j++) {
433 MachNode* mem = mem_ops.at(j)->as_Mach();
434 const TypePtr* mem_adr_type = NULL;
435 intptr_t mem_offset = 0;
436 const Node* mem_obj = mem->get_base_and_disp(mem_offset, mem_adr_type);
437 Block* mem_block = cfg->get_block_for_node(mem);
438 uint mem_index = block_index(mem_block, mem);
439
440 if (load_obj == NodeSentinel || mem_obj == NodeSentinel ||
441 load_obj == NULL || mem_obj == NULL ||
442 load_offset < 0 || mem_offset < 0) {
443 continue;
444 }
445
446 if (mem_obj != load_obj || mem_offset != load_offset) {
447 // Not the same addresses, not a candidate
448 continue;
449 }
450
451 if (load_block == mem_block) {
452 // Earlier accesses in the same block
453 if (mem_index < load_index && !block_has_safepoint(mem_block, mem_index + 1, load_index)) {
454 load->set_barrier_data(ZLoadBarrierElided);
455 }
456 } else if (mem_block->dominates(load_block)) {
457 // Dominating block? Look around for safepoints
458 ResourceMark rm;
459 Block_List stack;
460 VectorSet visited;
461 stack.push(load_block);
462 bool safepoint_found = block_has_safepoint(load_block);
463 while (!safepoint_found && stack.size() > 0) {
464 Block* block = stack.pop();
465 if (visited.test_set(block->_pre_order)) {
466 continue;
467 }
468 if (block_has_safepoint(block)) {
469 safepoint_found = true;
470 break;
471 }
472 if (block == mem_block) {
473 continue;
474 }
475
476 // Push predecessor blocks
477 for (uint p = 1; p < block->num_preds(); ++p) {
478 Block* pred = cfg->get_block_for_node(block->pred(p));
479 stack.push(pred);
480 }
481 }
482
483 if (!safepoint_found) {
484 load->set_barrier_data(ZLoadBarrierElided);
485 }
486 }
487 }
488 }
489 }
490
491 // == Reduced spilling optimization ==
492
493 void ZBarrierSetC2::compute_liveness_at_stubs() const {
494 ResourceMark rm;
495 Compile* const C = Compile::current();
496 Arena* const A = Thread::current()->resource_area();
497 PhaseCFG* const cfg = C->cfg();
498 PhaseRegAlloc* const regalloc = C->regalloc();
499 RegMask* const live = NEW_ARENA_ARRAY(A, RegMask, cfg->number_of_blocks() * sizeof(RegMask));
500 ZBarrierSetAssembler* const bs = ZBarrierSet::assembler();
501 Block_List worklist;
502
503 for (uint i = 0; i < cfg->number_of_blocks(); ++i) {
504 new ((void*)(live + i)) RegMask();
505 worklist.push(cfg->get_block(i));
506 }
507
508 while (worklist.size() > 0) {
509 const Block* const block = worklist.pop();
510 RegMask& old_live = live[block->_pre_order];
511 RegMask new_live;
512
513 // Initialize to union of successors
514 for (uint i = 0; i < block->_num_succs; i++) {
515 const uint succ_id = block->_succs[i]->_pre_order;
516 new_live.OR(live[succ_id]);
517 }
518
519 // Walk block backwards, computing liveness
520 for (int i = block->number_of_nodes() - 1; i >= 0; --i) {
521 const Node* const node = block->get_node(i);
522
523 // Remove def bits
524 const OptoReg::Name first = bs->refine_register(node, regalloc->get_reg_first(node));
525 const OptoReg::Name second = bs->refine_register(node, regalloc->get_reg_second(node));
526 if (first != OptoReg::Bad) {
527 new_live.Remove(first);
528 }
529 if (second != OptoReg::Bad) {
530 new_live.Remove(second);
531 }
532
533 // Add use bits
534 for (uint j = 1; j < node->req(); ++j) {
535 const Node* const use = node->in(j);
536 const OptoReg::Name first = bs->refine_register(use, regalloc->get_reg_first(use));
537 const OptoReg::Name second = bs->refine_register(use, regalloc->get_reg_second(use));
538 if (first != OptoReg::Bad) {
539 new_live.Insert(first);
540 }
541 if (second != OptoReg::Bad) {
542 new_live.Insert(second);
543 }
544 }
545
546 // If this node tracks liveness, update it
547 RegMask* const regs = barrier_set_state()->live(node);
548 if (regs != NULL) {
549 regs->OR(new_live);
550 }
551 }
552
553 // Now at block top, see if we have any changes
554 new_live.SUBTRACT(old_live);
555 if (new_live.is_NotEmpty()) {
556 // Liveness has refined, update and propagate to prior blocks
557 old_live.OR(new_live);
558 for (uint i = 1; i < block->num_preds(); ++i) {
559 Block* const pred = cfg->get_block_for_node(block->pred(i));
560 worklist.push(pred);
561 }
562 }
563 }
564 }