1 /*
2 * Copyright (c) 2012, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "ci/ciFlatArrayKlass.hpp"
27 #include "gc/shared/barrierSet.hpp"
28 #include "gc/shared/tlab_globals.hpp"
29 #include "opto/arraycopynode.hpp"
30 #include "oops/objArrayKlass.hpp"
31 #include "opto/convertnode.hpp"
32 #include "opto/vectornode.hpp"
33 #include "opto/graphKit.hpp"
34 #include "opto/macro.hpp"
35 #include "opto/runtime.hpp"
36 #include "opto/castnode.hpp"
37 #include "runtime/stubRoutines.hpp"
38 #include "utilities/align.hpp"
39 #include "utilities/powerOfTwo.hpp"
40
41 void PhaseMacroExpand::insert_mem_bar(Node** ctrl, Node** mem, int opcode, Node* precedent) {
42 MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);
43 mb->init_req(TypeFunc::Control, *ctrl);
44 mb->init_req(TypeFunc::Memory, *mem);
45 transform_later(mb);
46 *ctrl = new ProjNode(mb,TypeFunc::Control);
47 transform_later(*ctrl);
48 Node* mem_proj = new ProjNode(mb,TypeFunc::Memory);
49 transform_later(mem_proj);
50 *mem = mem_proj;
51 }
52
53 Node* PhaseMacroExpand::array_element_address(Node* ary, Node* idx, BasicType elembt) {
54 uint shift = exact_log2(type2aelembytes(elembt));
55 uint header = arrayOopDesc::base_offset_in_bytes(elembt);
56 Node* base = basic_plus_adr(ary, header);
57 #ifdef _LP64
58 // see comment in GraphKit::array_element_address
59 int index_max = max_jint - 1; // array size is max_jint, index is one less
60 const TypeLong* lidxtype = TypeLong::make(CONST64(0), index_max, Type::WidenMax);
61 idx = transform_later( new ConvI2LNode(idx, lidxtype) );
62 #endif
63 Node* scale = new LShiftXNode(idx, intcon(shift));
64 transform_later(scale);
65 return basic_plus_adr(ary, base, scale);
66 }
67
68 Node* PhaseMacroExpand::ConvI2L(Node* offset) {
69 return transform_later(new ConvI2LNode(offset));
70 }
71
72 Node* PhaseMacroExpand::make_leaf_call(Node* ctrl, Node* mem,
73 const TypeFunc* call_type, address call_addr,
74 const char* call_name,
75 const TypePtr* adr_type,
76 Node* parm0, Node* parm1,
77 Node* parm2, Node* parm3,
78 Node* parm4, Node* parm5,
79 Node* parm6, Node* parm7) {
80 Node* call = new CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);
81 call->init_req(TypeFunc::Control, ctrl);
82 call->init_req(TypeFunc::I_O , top());
83 call->init_req(TypeFunc::Memory , mem);
84 call->init_req(TypeFunc::ReturnAdr, top());
85 call->init_req(TypeFunc::FramePtr, top());
86
87 // Hook each parm in order. Stop looking at the first NULL.
88 if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);
89 if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);
90 if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);
91 if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);
92 if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);
93 if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);
94 if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);
95 if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);
96 /* close each nested if ===> */ } } } } } } } }
97 assert(call->in(call->req()-1) != NULL, "must initialize all parms");
98
99 return call;
100 }
101
102
103 //------------------------------generate_guard---------------------------
104 // Helper function for generating guarded fast-slow graph structures.
105 // The given 'test', if true, guards a slow path. If the test fails
106 // then a fast path can be taken. (We generally hope it fails.)
107 // In all cases, GraphKit::control() is updated to the fast path.
108 // The returned value represents the control for the slow path.
109 // The return value is never 'top'; it is either a valid control
110 // or NULL if it is obvious that the slow path can never be taken.
111 // Also, if region and the slow control are not NULL, the slow edge
112 // is appended to the region.
113 Node* PhaseMacroExpand::generate_guard(Node** ctrl, Node* test, RegionNode* region, float true_prob) {
114 if ((*ctrl)->is_top()) {
115 // Already short circuited.
116 return NULL;
117 }
118 // Build an if node and its projections.
119 // If test is true we take the slow path, which we assume is uncommon.
120 if (_igvn.type(test) == TypeInt::ZERO) {
121 // The slow branch is never taken. No need to build this guard.
122 return NULL;
123 }
124
125 IfNode* iff = new IfNode(*ctrl, test, true_prob, COUNT_UNKNOWN);
126 transform_later(iff);
127
128 Node* if_slow = new IfTrueNode(iff);
129 transform_later(if_slow);
130
131 if (region != NULL) {
132 region->add_req(if_slow);
133 }
134
135 Node* if_fast = new IfFalseNode(iff);
136 transform_later(if_fast);
137
138 *ctrl = if_fast;
139
140 return if_slow;
141 }
142
143 Node* PhaseMacroExpand::generate_slow_guard(Node** ctrl, Node* test, RegionNode* region) {
144 return generate_guard(ctrl, test, region, PROB_UNLIKELY_MAG(3));
145 }
146
147 inline Node* PhaseMacroExpand::generate_fair_guard(Node** ctrl, Node* test, RegionNode* region) {
148 return generate_guard(ctrl, test, region, PROB_FAIR);
149 }
150
151 void PhaseMacroExpand::generate_negative_guard(Node** ctrl, Node* index, RegionNode* region) {
152 if ((*ctrl)->is_top())
153 return; // already stopped
154 if (_igvn.type(index)->higher_equal(TypeInt::POS)) // [0,maxint]
155 return; // index is already adequately typed
156 Node* cmp_lt = new CmpINode(index, intcon(0));
157 transform_later(cmp_lt);
158 Node* bol_lt = new BoolNode(cmp_lt, BoolTest::lt);
159 transform_later(bol_lt);
160 generate_guard(ctrl, bol_lt, region, PROB_MIN);
161 }
162
163 void PhaseMacroExpand::generate_limit_guard(Node** ctrl, Node* offset, Node* subseq_length, Node* array_length, RegionNode* region) {
164 if ((*ctrl)->is_top())
165 return; // already stopped
166 bool zero_offset = _igvn.type(offset) == TypeInt::ZERO;
167 if (zero_offset && subseq_length->eqv_uncast(array_length))
168 return; // common case of whole-array copy
169 Node* last = subseq_length;
170 if (!zero_offset) { // last += offset
171 last = new AddINode(last, offset);
172 transform_later(last);
173 }
174 Node* cmp_lt = new CmpUNode(array_length, last);
175 transform_later(cmp_lt);
176 Node* bol_lt = new BoolNode(cmp_lt, BoolTest::lt);
177 transform_later(bol_lt);
178 generate_guard(ctrl, bol_lt, region, PROB_MIN);
179 }
180
181 //
182 // Partial in-lining handling for smaller conjoint/disjoint array copies having
183 // length(in bytes) less than ArrayOperationPartialInlineSize.
184 // if (length <= ArrayOperationPartialInlineSize) {
185 // partial_inlining_block:
186 // mask = Mask_Gen
187 // vload = LoadVectorMasked src , mask
188 // StoreVectorMasked dst, mask, vload
189 // } else {
190 // stub_block:
191 // callstub array_copy
192 // }
193 // exit_block:
194 // Phi = label partial_inlining_block:mem , label stub_block:mem (filled by caller)
195 // mem = MergeMem (Phi)
196 // control = stub_block
197 //
198 // Exit_block and associated phi(memory) are partially initialized for partial_in-lining_block
199 // edges. Remaining edges for exit_block coming from stub_block are connected by the caller
200 // post stub nodes creation.
201 //
202
203 void PhaseMacroExpand::generate_partial_inlining_block(Node** ctrl, MergeMemNode** mem, const TypePtr* adr_type,
204 RegionNode** exit_block, Node** result_memory, Node* length,
205 Node* src_start, Node* dst_start, BasicType type) {
206 const TypePtr *src_adr_type = _igvn.type(src_start)->isa_ptr();
207 Node* inline_block = NULL;
208 Node* stub_block = NULL;
209
210 int const_len = -1;
211 const TypeInt* lty = NULL;
212 uint shift = exact_log2(type2aelembytes(type));
213 if (length->Opcode() == Op_ConvI2L) {
214 lty = _igvn.type(length->in(1))->isa_int();
215 } else {
216 lty = _igvn.type(length)->isa_int();
217 }
218 if (lty && lty->is_con()) {
219 const_len = lty->get_con() << shift;
220 }
221
222 // Return if copy length is greater than partial inline size limit or
223 // target does not supports masked load/stores.
224 int lane_count = ArrayCopyNode::get_partial_inline_vector_lane_count(type, const_len);
225 if ( const_len > ArrayOperationPartialInlineSize ||
226 !Matcher::match_rule_supported_vector(Op_LoadVectorMasked, lane_count, type) ||
227 !Matcher::match_rule_supported_vector(Op_StoreVectorMasked, lane_count, type) ||
228 !Matcher::match_rule_supported_vector(Op_VectorMaskGen, lane_count, type)) {
229 return;
230 }
231
232 int inline_limit = ArrayOperationPartialInlineSize / type2aelembytes(type);
233 Node* casted_length = new CastLLNode(*ctrl, length, TypeLong::make(0, inline_limit, Type::WidenMin));
234 transform_later(casted_length);
235 Node* copy_bytes = new LShiftXNode(length, intcon(shift));
236 transform_later(copy_bytes);
237
238 Node* cmp_le = new CmpULNode(copy_bytes, longcon(ArrayOperationPartialInlineSize));
239 transform_later(cmp_le);
240 Node* bol_le = new BoolNode(cmp_le, BoolTest::le);
241 transform_later(bol_le);
242 inline_block = generate_guard(ctrl, bol_le, NULL, PROB_FAIR);
243 stub_block = *ctrl;
244
245 Node* mask_gen = VectorMaskGenNode::make(casted_length, type);
246 transform_later(mask_gen);
247
248 unsigned vec_size = lane_count * type2aelembytes(type);
249 if (C->max_vector_size() < vec_size) {
250 C->set_max_vector_size(vec_size);
251 }
252
253 const TypeVect * vt = TypeVect::make(type, lane_count);
254 Node* mm = (*mem)->memory_at(C->get_alias_index(src_adr_type));
255 Node* masked_load = new LoadVectorMaskedNode(inline_block, mm, src_start,
256 src_adr_type, vt, mask_gen);
257 transform_later(masked_load);
258
259 mm = (*mem)->memory_at(C->get_alias_index(adr_type));
260 Node* masked_store = new StoreVectorMaskedNode(inline_block, mm, dst_start,
261 masked_load, adr_type, mask_gen);
262 transform_later(masked_store);
263
264 // Convergence region for inline_block and stub_block.
265 *exit_block = new RegionNode(3);
266 transform_later(*exit_block);
267 (*exit_block)->init_req(1, inline_block);
268 *result_memory = new PhiNode(*exit_block, Type::MEMORY, adr_type);
269 transform_later(*result_memory);
270 (*result_memory)->init_req(1, masked_store);
271
272 *ctrl = stub_block;
273 }
274
275
276 Node* PhaseMacroExpand::generate_nonpositive_guard(Node** ctrl, Node* index, bool never_negative) {
277 if ((*ctrl)->is_top()) return NULL;
278
279 if (_igvn.type(index)->higher_equal(TypeInt::POS1)) // [1,maxint]
280 return NULL; // index is already adequately typed
281 Node* cmp_le = new CmpINode(index, intcon(0));
282 transform_later(cmp_le);
283 BoolTest::mask le_or_eq = (never_negative ? BoolTest::eq : BoolTest::le);
284 Node* bol_le = new BoolNode(cmp_le, le_or_eq);
285 transform_later(bol_le);
286 Node* is_notp = generate_guard(ctrl, bol_le, NULL, PROB_MIN);
287
288 return is_notp;
289 }
290
291 Node* PhaseMacroExpand::array_lh_test(Node* array, jint mask) {
292 Node* klass_adr = basic_plus_adr(array, oopDesc::klass_offset_in_bytes());
293 Node* klass = transform_later(LoadKlassNode::make(_igvn, NULL, C->immutable_memory(), klass_adr, TypeInstPtr::KLASS, TypeInstKlassPtr::OBJECT));
294 Node* lh_addr = basic_plus_adr(klass, in_bytes(Klass::layout_helper_offset()));
295 Node* lh_val = _igvn.transform(LoadNode::make(_igvn, NULL, C->immutable_memory(), lh_addr, lh_addr->bottom_type()->is_ptr(), TypeInt::INT, T_INT, MemNode::unordered));
296 Node* masked = transform_later(new AndINode(lh_val, intcon(mask)));
297 Node* cmp = transform_later(new CmpINode(masked, intcon(0)));
298 return transform_later(new BoolNode(cmp, BoolTest::ne));
299 }
300
301 Node* PhaseMacroExpand::generate_flat_array_guard(Node** ctrl, Node* array, RegionNode* region) {
302 assert(UseFlatArray, "can never be flattened");
303 return generate_fair_guard(ctrl, array_lh_test(array, Klass::_lh_array_tag_flat_value_bit_inplace), region);
304 }
305
306 Node* PhaseMacroExpand::generate_null_free_array_guard(Node** ctrl, Node* array, RegionNode* region) {
307 assert(EnableValhalla, "can never be null free");
308 return generate_fair_guard(ctrl, array_lh_test(array, Klass::_lh_null_free_array_bit_inplace), region);
309 }
310
311 void PhaseMacroExpand::finish_arraycopy_call(Node* call, Node** ctrl, MergeMemNode** mem, const TypePtr* adr_type) {
312 transform_later(call);
313
314 *ctrl = new ProjNode(call,TypeFunc::Control);
315 transform_later(*ctrl);
316 Node* newmem = new ProjNode(call, TypeFunc::Memory);
317 transform_later(newmem);
318
319 uint alias_idx = C->get_alias_index(adr_type);
320 if (alias_idx != Compile::AliasIdxBot) {
321 *mem = MergeMemNode::make(*mem);
322 (*mem)->set_memory_at(alias_idx, newmem);
323 } else {
324 *mem = MergeMemNode::make(newmem);
325 }
326 transform_later(*mem);
327 }
328
329 address PhaseMacroExpand::basictype2arraycopy(BasicType t,
330 Node* src_offset,
331 Node* dest_offset,
332 bool disjoint_bases,
333 const char* &name,
334 bool dest_uninitialized) {
335 const TypeInt* src_offset_inttype = _igvn.find_int_type(src_offset);
336 const TypeInt* dest_offset_inttype = _igvn.find_int_type(dest_offset);
337
338 bool aligned = false;
339 bool disjoint = disjoint_bases;
340
341 // if the offsets are the same, we can treat the memory regions as
342 // disjoint, because either the memory regions are in different arrays,
343 // or they are identical (which we can treat as disjoint.) We can also
344 // treat a copy with a destination index less that the source index
345 // as disjoint since a low->high copy will work correctly in this case.
346 if (src_offset_inttype != NULL && src_offset_inttype->is_con() &&
347 dest_offset_inttype != NULL && dest_offset_inttype->is_con()) {
348 // both indices are constants
349 int s_offs = src_offset_inttype->get_con();
350 int d_offs = dest_offset_inttype->get_con();
351 int element_size = type2aelembytes(t);
352 aligned = ((arrayOopDesc::base_offset_in_bytes(t) + s_offs * element_size) % HeapWordSize == 0) &&
353 ((arrayOopDesc::base_offset_in_bytes(t) + d_offs * element_size) % HeapWordSize == 0);
354 if (s_offs >= d_offs) disjoint = true;
355 } else if (src_offset == dest_offset && src_offset != NULL) {
356 // This can occur if the offsets are identical non-constants.
357 disjoint = true;
358 }
359
360 return StubRoutines::select_arraycopy_function(t, aligned, disjoint, name, dest_uninitialized);
361 }
362
363 #define XTOP LP64_ONLY(COMMA top())
364
365 // Generate an optimized call to arraycopy.
366 // Caller must guard against non-arrays.
367 // Caller must determine a common array basic-type for both arrays.
368 // Caller must validate offsets against array bounds.
369 // The slow_region has already collected guard failure paths
370 // (such as out of bounds length or non-conformable array types).
371 // The generated code has this shape, in general:
372 //
373 // if (length == 0) return // via zero_path
374 // slowval = -1
375 // if (types unknown) {
376 // slowval = call generic copy loop
377 // if (slowval == 0) return // via checked_path
378 // } else if (indexes in bounds) {
379 // if ((is object array) && !(array type check)) {
380 // slowval = call checked copy loop
381 // if (slowval == 0) return // via checked_path
382 // } else {
383 // call bulk copy loop
384 // return // via fast_path
385 // }
386 // }
387 // // adjust params for remaining work:
388 // if (slowval != -1) {
389 // n = -1^slowval; src_offset += n; dest_offset += n; length -= n
390 // }
391 // slow_region:
392 // call slow arraycopy(src, src_offset, dest, dest_offset, length)
393 // return // via slow_call_path
394 //
395 // This routine is used from several intrinsics: System.arraycopy,
396 // Object.clone (the array subcase), and Arrays.copyOf[Range].
397 //
398 Node* PhaseMacroExpand::generate_arraycopy(ArrayCopyNode *ac, AllocateArrayNode* alloc,
399 Node** ctrl, MergeMemNode* mem, Node** io,
400 const TypePtr* adr_type,
401 BasicType basic_elem_type,
402 Node* src, Node* src_offset,
403 Node* dest, Node* dest_offset,
404 Node* copy_length,
405 Node* dest_length,
406 bool disjoint_bases,
407 bool length_never_negative,
408 RegionNode* slow_region) {
409 if (slow_region == NULL) {
410 slow_region = new RegionNode(1);
411 transform_later(slow_region);
412 }
413
414 Node* original_dest = dest;
415 bool dest_needs_zeroing = false;
416 bool acopy_to_uninitialized = false;
417 Node* default_value = NULL;
418 Node* raw_default_value = NULL;
419
420 // See if this is the initialization of a newly-allocated array.
421 // If so, we will take responsibility here for initializing it to zero.
422 // (Note: Because tightly_coupled_allocation performs checks on the
423 // out-edges of the dest, we need to avoid making derived pointers
424 // from it until we have checked its uses.)
425 if (ReduceBulkZeroing
426 && !(UseTLAB && ZeroTLAB) // pointless if already zeroed
427 && basic_elem_type != T_CONFLICT // avoid corner case
428 && !src->eqv_uncast(dest)
429 && alloc != NULL
430 && _igvn.find_int_con(alloc->in(AllocateNode::ALength), 1) > 0) {
431 assert(ac->is_alloc_tightly_coupled(), "sanity");
432 // acopy to uninitialized tightly coupled allocations
433 // needs zeroing outside the copy range
434 // and the acopy itself will be to uninitialized memory
435 acopy_to_uninitialized = true;
436 if (alloc->maybe_set_complete(&_igvn)) {
437 // "You break it, you buy it."
438 InitializeNode* init = alloc->initialization();
439 assert(init->is_complete(), "we just did this");
440 init->set_complete_with_arraycopy();
441 assert(dest->is_CheckCastPP(), "sanity");
442 assert(dest->in(0)->in(0) == init, "dest pinned");
443 adr_type = TypeRawPtr::BOTTOM; // all initializations are into raw memory
444 // From this point on, every exit path is responsible for
445 // initializing any non-copied parts of the object to zero.
446 // Also, if this flag is set we make sure that arraycopy interacts properly
447 // with G1, eliding pre-barriers. See CR 6627983.
448 dest_needs_zeroing = true;
449 default_value = alloc->in(AllocateNode::DefaultValue);
450 raw_default_value = alloc->in(AllocateNode::RawDefaultValue);
451 } else {
452 // dest_need_zeroing = false;
453 }
454 } else {
455 // No zeroing elimination needed here.
456 alloc = NULL;
457 acopy_to_uninitialized = false;
458 //original_dest = dest;
459 //dest_needs_zeroing = false;
460 }
461
462 uint alias_idx = C->get_alias_index(adr_type);
463
464 // Results are placed here:
465 enum { fast_path = 1, // normal void-returning assembly stub
466 checked_path = 2, // special assembly stub with cleanup
467 slow_call_path = 3, // something went wrong; call the VM
468 zero_path = 4, // bypass when length of copy is zero
469 bcopy_path = 5, // copy primitive array by 64-bit blocks
470 PATH_LIMIT = 6
471 };
472 RegionNode* result_region = new RegionNode(PATH_LIMIT);
473 PhiNode* result_i_o = new PhiNode(result_region, Type::ABIO);
474 PhiNode* result_memory = new PhiNode(result_region, Type::MEMORY, adr_type);
475 assert(adr_type != TypePtr::BOTTOM, "must be RawMem or a T[] slice");
476 transform_later(result_region);
477 transform_later(result_i_o);
478 transform_later(result_memory);
479
480 // The slow_control path:
481 Node* slow_control;
482 Node* slow_i_o = *io;
483 Node* slow_mem = mem->memory_at(alias_idx);
484 DEBUG_ONLY(slow_control = (Node*) badAddress);
485
486 // Checked control path:
487 Node* checked_control = top();
488 Node* checked_mem = NULL;
489 Node* checked_i_o = NULL;
490 Node* checked_value = NULL;
491
492 if (basic_elem_type == T_CONFLICT) {
493 assert(!dest_needs_zeroing, "");
494 Node* cv = generate_generic_arraycopy(ctrl, &mem,
495 adr_type,
496 src, src_offset, dest, dest_offset,
497 copy_length, acopy_to_uninitialized);
498 if (cv == NULL) cv = intcon(-1); // failure (no stub available)
499 checked_control = *ctrl;
500 checked_i_o = *io;
501 checked_mem = mem->memory_at(alias_idx);
502 checked_value = cv;
503 *ctrl = top();
504 }
505
506 Node* not_pos = generate_nonpositive_guard(ctrl, copy_length, length_never_negative);
507 if (not_pos != NULL) {
508 Node* local_ctrl = not_pos, *local_io = *io;
509 MergeMemNode* local_mem = MergeMemNode::make(mem);
510 transform_later(local_mem);
511
512 // (6) length must not be negative.
513 if (!length_never_negative) {
514 generate_negative_guard(&local_ctrl, copy_length, slow_region);
515 }
516
517 // copy_length is 0.
518 if (dest_needs_zeroing) {
519 assert(!local_ctrl->is_top(), "no ctrl?");
520 if (copy_length->eqv_uncast(dest_length)
521 || _igvn.find_int_con(dest_length, 1) <= 0) {
522 // There is no zeroing to do. No need for a secondary raw memory barrier.
523 } else {
524 // Clear the whole thing since there are no source elements to copy.
525 generate_clear_array(local_ctrl, local_mem,
526 adr_type, dest,
527 default_value, raw_default_value,
528 basic_elem_type,
529 intcon(0), NULL,
530 alloc->in(AllocateNode::AllocSize));
531 // Use a secondary InitializeNode as raw memory barrier.
532 // Currently it is needed only on this path since other
533 // paths have stub or runtime calls as raw memory barriers.
534 MemBarNode* mb = MemBarNode::make(C, Op_Initialize,
535 Compile::AliasIdxRaw,
536 top());
537 transform_later(mb);
538 mb->set_req(TypeFunc::Control,local_ctrl);
539 mb->set_req(TypeFunc::Memory, local_mem->memory_at(Compile::AliasIdxRaw));
540 local_ctrl = transform_later(new ProjNode(mb, TypeFunc::Control));
541 local_mem->set_memory_at(Compile::AliasIdxRaw, transform_later(new ProjNode(mb, TypeFunc::Memory)));
542
543 InitializeNode* init = mb->as_Initialize();
544 init->set_complete(&_igvn); // (there is no corresponding AllocateNode)
545 }
546 }
547
548 // Present the results of the fast call.
549 result_region->init_req(zero_path, local_ctrl);
550 result_i_o ->init_req(zero_path, local_io);
551 result_memory->init_req(zero_path, local_mem->memory_at(alias_idx));
552 }
553
554 if (!(*ctrl)->is_top() && dest_needs_zeroing) {
555 // We have to initialize the *uncopied* part of the array to zero.
556 // The copy destination is the slice dest[off..off+len]. The other slices
557 // are dest_head = dest[0..off] and dest_tail = dest[off+len..dest.length].
558 Node* dest_size = alloc->in(AllocateNode::AllocSize);
559 Node* dest_tail = transform_later( new AddINode(dest_offset, copy_length));
560
561 // If there is a head section that needs zeroing, do it now.
562 if (_igvn.find_int_con(dest_offset, -1) != 0) {
563 generate_clear_array(*ctrl, mem,
564 adr_type, dest,
565 default_value, raw_default_value,
566 basic_elem_type,
567 intcon(0), dest_offset,
568 NULL);
569 }
570
571 // Next, perform a dynamic check on the tail length.
572 // It is often zero, and we can win big if we prove this.
573 // There are two wins: Avoid generating the ClearArray
574 // with its attendant messy index arithmetic, and upgrade
575 // the copy to a more hardware-friendly word size of 64 bits.
576 Node* tail_ctl = NULL;
577 if (!(*ctrl)->is_top() && !dest_tail->eqv_uncast(dest_length)) {
578 Node* cmp_lt = transform_later( new CmpINode(dest_tail, dest_length) );
579 Node* bol_lt = transform_later( new BoolNode(cmp_lt, BoolTest::lt) );
580 tail_ctl = generate_slow_guard(ctrl, bol_lt, NULL);
581 assert(tail_ctl != NULL || !(*ctrl)->is_top(), "must be an outcome");
582 }
583
584 // At this point, let's assume there is no tail.
585 if (!(*ctrl)->is_top() && alloc != NULL && basic_elem_type != T_OBJECT) {
586 // There is no tail. Try an upgrade to a 64-bit copy.
587 bool didit = false;
588 {
589 Node* local_ctrl = *ctrl, *local_io = *io;
590 MergeMemNode* local_mem = MergeMemNode::make(mem);
591 transform_later(local_mem);
592
593 didit = generate_block_arraycopy(&local_ctrl, &local_mem, local_io,
594 adr_type, basic_elem_type, alloc,
595 src, src_offset, dest, dest_offset,
596 dest_size, acopy_to_uninitialized);
597 if (didit) {
598 // Present the results of the block-copying fast call.
599 result_region->init_req(bcopy_path, local_ctrl);
600 result_i_o ->init_req(bcopy_path, local_io);
601 result_memory->init_req(bcopy_path, local_mem->memory_at(alias_idx));
602 }
603 }
604 if (didit) {
605 *ctrl = top(); // no regular fast path
606 }
607 }
608
609 // Clear the tail, if any.
610 if (tail_ctl != NULL) {
611 Node* notail_ctl = (*ctrl)->is_top() ? NULL : *ctrl;
612 *ctrl = tail_ctl;
613 if (notail_ctl == NULL) {
614 generate_clear_array(*ctrl, mem,
615 adr_type, dest,
616 default_value, raw_default_value,
617 basic_elem_type,
618 dest_tail, NULL,
619 dest_size);
620 } else {
621 // Make a local merge.
622 Node* done_ctl = transform_later(new RegionNode(3));
623 Node* done_mem = transform_later(new PhiNode(done_ctl, Type::MEMORY, adr_type));
624 done_ctl->init_req(1, notail_ctl);
625 done_mem->init_req(1, mem->memory_at(alias_idx));
626 generate_clear_array(*ctrl, mem,
627 adr_type, dest,
628 default_value, raw_default_value,
629 basic_elem_type,
630 dest_tail, NULL,
631 dest_size);
632 done_ctl->init_req(2, *ctrl);
633 done_mem->init_req(2, mem->memory_at(alias_idx));
634 *ctrl = done_ctl;
635 mem->set_memory_at(alias_idx, done_mem);
636 }
637 }
638 }
639
640 BasicType copy_type = basic_elem_type;
641 assert(basic_elem_type != T_ARRAY, "caller must fix this");
642 if (!(*ctrl)->is_top() && copy_type == T_OBJECT) {
643 // If src and dest have compatible element types, we can copy bits.
644 // Types S[] and D[] are compatible if D is a supertype of S.
645 //
646 // If they are not, we will use checked_oop_disjoint_arraycopy,
647 // which performs a fast optimistic per-oop check, and backs off
648 // further to JVM_ArrayCopy on the first per-oop check that fails.
649 // (Actually, we don't move raw bits only; the GC requires card marks.)
650
651 // We don't need a subtype check for validated copies and Object[].clone()
652 bool skip_subtype_check = ac->is_arraycopy_validated() || ac->is_copyof_validated() ||
653 ac->is_copyofrange_validated() || ac->is_clone_oop_array();
654 if (!skip_subtype_check) {
655 // Get the klass* for both src and dest
656 Node* src_klass = ac->in(ArrayCopyNode::SrcKlass);
657 Node* dest_klass = ac->in(ArrayCopyNode::DestKlass);
658
659 assert(src_klass != NULL && dest_klass != NULL, "should have klasses");
660
661 // Generate the subtype check.
662 // This might fold up statically, or then again it might not.
663 //
664 // Non-static example: Copying List<String>.elements to a new String[].
665 // The backing store for a List<String> is always an Object[],
666 // but its elements are always type String, if the generic types
667 // are correct at the source level.
668 //
669 // Test S[] against D[], not S against D, because (probably)
670 // the secondary supertype cache is less busy for S[] than S.
671 // This usually only matters when D is an interface.
672 Node* not_subtype_ctrl = Phase::gen_subtype_check(src_klass, dest_klass, ctrl, mem, _igvn);
673 // Plug failing path into checked_oop_disjoint_arraycopy
674 if (not_subtype_ctrl != top()) {
675 Node* local_ctrl = not_subtype_ctrl;
676 MergeMemNode* local_mem = MergeMemNode::make(mem);
677 transform_later(local_mem);
678
679 // (At this point we can assume disjoint_bases, since types differ.)
680 int ek_offset = in_bytes(ObjArrayKlass::element_klass_offset());
681 Node* p1 = basic_plus_adr(dest_klass, ek_offset);
682 Node* n1 = LoadKlassNode::make(_igvn, NULL, C->immutable_memory(), p1, TypeRawPtr::BOTTOM);
683 Node* dest_elem_klass = transform_later(n1);
684 Node* cv = generate_checkcast_arraycopy(&local_ctrl, &local_mem,
685 adr_type,
686 dest_elem_klass,
687 src, src_offset, dest, dest_offset,
688 ConvI2X(copy_length), acopy_to_uninitialized);
689 if (cv == NULL) cv = intcon(-1); // failure (no stub available)
690 checked_control = local_ctrl;
691 checked_i_o = *io;
692 checked_mem = local_mem->memory_at(alias_idx);
693 checked_value = cv;
694 }
695 }
696 // At this point we know we do not need type checks on oop stores.
697
698 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
699 if (!bs->array_copy_requires_gc_barriers(alloc != NULL, copy_type, false, false, BarrierSetC2::Expansion)) {
700 // If we do not need gc barriers, copy using the jint or jlong stub.
701 copy_type = LP64_ONLY(UseCompressedOops ? T_INT : T_LONG) NOT_LP64(T_INT);
702 assert(type2aelembytes(basic_elem_type) == type2aelembytes(copy_type),
703 "sizes agree");
704 }
705 }
706
707 bool is_partial_array_copy = false;
708 if (!(*ctrl)->is_top()) {
709 // Generate the fast path, if possible.
710 Node* local_ctrl = *ctrl;
711 MergeMemNode* local_mem = MergeMemNode::make(mem);
712 transform_later(local_mem);
713 is_partial_array_copy = generate_unchecked_arraycopy(&local_ctrl, &local_mem,
714 adr_type, copy_type, disjoint_bases,
715 src, src_offset, dest, dest_offset,
716 ConvI2X(copy_length), acopy_to_uninitialized);
717
718 // Present the results of the fast call.
719 result_region->init_req(fast_path, local_ctrl);
720 result_i_o ->init_req(fast_path, *io);
721 result_memory->init_req(fast_path, local_mem->memory_at(alias_idx));
722 }
723
724 // Here are all the slow paths up to this point, in one bundle:
725 assert(slow_region != NULL, "allocated on entry");
726 slow_control = slow_region;
727 DEBUG_ONLY(slow_region = (RegionNode*)badAddress);
728
729 *ctrl = checked_control;
730 if (!(*ctrl)->is_top()) {
731 // Clean up after the checked call.
732 // The returned value is either 0 or -1^K,
733 // where K = number of partially transferred array elements.
734 Node* cmp = new CmpINode(checked_value, intcon(0));
735 transform_later(cmp);
736 Node* bol = new BoolNode(cmp, BoolTest::eq);
737 transform_later(bol);
738 IfNode* iff = new IfNode(*ctrl, bol, PROB_MAX, COUNT_UNKNOWN);
739 transform_later(iff);
740
741 // If it is 0, we are done, so transfer to the end.
742 Node* checks_done = new IfTrueNode(iff);
743 transform_later(checks_done);
744 result_region->init_req(checked_path, checks_done);
745 result_i_o ->init_req(checked_path, checked_i_o);
746 result_memory->init_req(checked_path, checked_mem);
747
748 // If it is not zero, merge into the slow call.
749 *ctrl = new IfFalseNode(iff);
750 transform_later(*ctrl);
751 RegionNode* slow_reg2 = new RegionNode(3);
752 PhiNode* slow_i_o2 = new PhiNode(slow_reg2, Type::ABIO);
753 PhiNode* slow_mem2 = new PhiNode(slow_reg2, Type::MEMORY, adr_type);
754 transform_later(slow_reg2);
755 transform_later(slow_i_o2);
756 transform_later(slow_mem2);
757 slow_reg2 ->init_req(1, slow_control);
758 slow_i_o2 ->init_req(1, slow_i_o);
759 slow_mem2 ->init_req(1, slow_mem);
760 slow_reg2 ->init_req(2, *ctrl);
761 slow_i_o2 ->init_req(2, checked_i_o);
762 slow_mem2 ->init_req(2, checked_mem);
763
764 slow_control = slow_reg2;
765 slow_i_o = slow_i_o2;
766 slow_mem = slow_mem2;
767
768 if (alloc != NULL) {
769 // We'll restart from the very beginning, after zeroing the whole thing.
770 // This can cause double writes, but that's OK since dest is brand new.
771 // So we ignore the low 31 bits of the value returned from the stub.
772 } else {
773 // We must continue the copy exactly where it failed, or else
774 // another thread might see the wrong number of writes to dest.
775 Node* checked_offset = new XorINode(checked_value, intcon(-1));
776 Node* slow_offset = new PhiNode(slow_reg2, TypeInt::INT);
777 transform_later(checked_offset);
778 transform_later(slow_offset);
779 slow_offset->init_req(1, intcon(0));
780 slow_offset->init_req(2, checked_offset);
781
782 // Adjust the arguments by the conditionally incoming offset.
783 Node* src_off_plus = new AddINode(src_offset, slow_offset);
784 transform_later(src_off_plus);
785 Node* dest_off_plus = new AddINode(dest_offset, slow_offset);
786 transform_later(dest_off_plus);
787 Node* length_minus = new SubINode(copy_length, slow_offset);
788 transform_later(length_minus);
789
790 // Tweak the node variables to adjust the code produced below:
791 src_offset = src_off_plus;
792 dest_offset = dest_off_plus;
793 copy_length = length_minus;
794 }
795 }
796 *ctrl = slow_control;
797 if (!(*ctrl)->is_top()) {
798 Node* local_ctrl = *ctrl, *local_io = slow_i_o;
799 MergeMemNode* local_mem = MergeMemNode::make(mem);
800 transform_later(local_mem);
801
802 // Generate the slow path, if needed.
803 local_mem->set_memory_at(alias_idx, slow_mem);
804
805 if (dest_needs_zeroing) {
806 generate_clear_array(local_ctrl, local_mem,
807 adr_type, dest,
808 default_value, raw_default_value,
809 basic_elem_type,
810 intcon(0), NULL,
811 alloc->in(AllocateNode::AllocSize));
812 }
813
814 local_mem = generate_slow_arraycopy(ac,
815 &local_ctrl, local_mem, &local_io,
816 adr_type,
817 src, src_offset, dest, dest_offset,
818 copy_length, /*dest_uninitialized*/false);
819
820 result_region->init_req(slow_call_path, local_ctrl);
821 result_i_o ->init_req(slow_call_path, local_io);
822 result_memory->init_req(slow_call_path, local_mem->memory_at(alias_idx));
823 } else {
824 ShouldNotReachHere(); // no call to generate_slow_arraycopy:
825 // projections were not extracted
826 }
827
828 // Remove unused edges.
829 for (uint i = 1; i < result_region->req(); i++) {
830 if (result_region->in(i) == NULL) {
831 result_region->init_req(i, top());
832 }
833 }
834
835 // Finished; return the combined state.
836 *ctrl = result_region;
837 *io = result_i_o;
838 mem->set_memory_at(alias_idx, result_memory);
839
840 // mem no longer guaranteed to stay a MergeMemNode
841 Node* out_mem = mem;
842 DEBUG_ONLY(mem = NULL);
843
844 // The memory edges above are precise in order to model effects around
845 // array copies accurately to allow value numbering of field loads around
846 // arraycopy. Such field loads, both before and after, are common in Java
847 // collections and similar classes involving header/array data structures.
848 //
849 // But with low number of register or when some registers are used or killed
850 // by arraycopy calls it causes registers spilling on stack. See 6544710.
851 // The next memory barrier is added to avoid it. If the arraycopy can be
852 // optimized away (which it can, sometimes) then we can manually remove
853 // the membar also.
854 //
855 // Do not let reads from the cloned object float above the arraycopy.
856 if (alloc != NULL && !alloc->initialization()->does_not_escape()) {
857 // Do not let stores that initialize this object be reordered with
858 // a subsequent store that would make this object accessible by
859 // other threads.
860 insert_mem_bar(ctrl, &out_mem, Op_MemBarStoreStore);
861 } else {
862 insert_mem_bar(ctrl, &out_mem, Op_MemBarCPUOrder);
863 }
864
865 if (is_partial_array_copy) {
866 assert((*ctrl)->is_Proj(), "MemBar control projection");
867 assert((*ctrl)->in(0)->isa_MemBar(), "MemBar node");
868 (*ctrl)->in(0)->isa_MemBar()->set_trailing_partial_array_copy();
869 }
870
871 _igvn.replace_node(_callprojs->fallthrough_memproj, out_mem);
872 if (_callprojs->fallthrough_ioproj != NULL) {
873 _igvn.replace_node(_callprojs->fallthrough_ioproj, *io);
874 }
875 _igvn.replace_node(_callprojs->fallthrough_catchproj, *ctrl);
876
877 #ifdef ASSERT
878 const TypeOopPtr* dest_t = _igvn.type(dest)->is_oopptr();
879 if (dest_t->is_known_instance() && !is_partial_array_copy) {
880 ArrayCopyNode* ac = NULL;
881 assert(ArrayCopyNode::may_modify(dest_t, (*ctrl)->in(0)->as_MemBar(), &_igvn, ac), "dependency on arraycopy lost");
882 assert(ac == NULL, "no arraycopy anymore");
883 }
884 #endif
885
886 return out_mem;
887 }
888
889 // Helper for initialization of arrays, creating a ClearArray.
890 // It writes zero bits in [start..end), within the body of an array object.
891 // The memory effects are all chained onto the 'adr_type' alias category.
892 //
893 // Since the object is otherwise uninitialized, we are free
894 // to put a little "slop" around the edges of the cleared area,
895 // as long as it does not go back into the array's header,
896 // or beyond the array end within the heap.
897 //
898 // The lower edge can be rounded down to the nearest jint and the
899 // upper edge can be rounded up to the nearest MinObjAlignmentInBytes.
900 //
901 // Arguments:
902 // adr_type memory slice where writes are generated
903 // dest oop of the destination array
904 // basic_elem_type element type of the destination
905 // slice_idx array index of first element to store
906 // slice_len number of elements to store (or NULL)
907 // dest_size total size in bytes of the array object
908 //
909 // Exactly one of slice_len or dest_size must be non-NULL.
910 // If dest_size is non-NULL, zeroing extends to the end of the object.
911 // If slice_len is non-NULL, the slice_idx value must be a constant.
912 void PhaseMacroExpand::generate_clear_array(Node* ctrl, MergeMemNode* merge_mem,
913 const TypePtr* adr_type,
914 Node* dest,
915 Node* val,
916 Node* raw_val,
917 BasicType basic_elem_type,
918 Node* slice_idx,
919 Node* slice_len,
920 Node* dest_size) {
921 // one or the other but not both of slice_len and dest_size:
922 assert((slice_len != NULL? 1: 0) + (dest_size != NULL? 1: 0) == 1, "");
923 if (slice_len == NULL) slice_len = top();
924 if (dest_size == NULL) dest_size = top();
925
926 uint alias_idx = C->get_alias_index(adr_type);
927
928 // operate on this memory slice:
929 Node* mem = merge_mem->memory_at(alias_idx); // memory slice to operate on
930
931 // scaling and rounding of indexes:
932 assert(basic_elem_type != T_PRIMITIVE_OBJECT, "should have been converted to a basic type copy");
933 int scale = exact_log2(type2aelembytes(basic_elem_type));
934 int abase = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
935 int clear_low = (-1 << scale) & (BytesPerInt - 1);
936 int bump_bit = (-1 << scale) & BytesPerInt;
937
938 // determine constant starts and ends
939 const intptr_t BIG_NEG = -128;
940 assert(BIG_NEG + 2*abase < 0, "neg enough");
941 intptr_t slice_idx_con = (intptr_t) _igvn.find_int_con(slice_idx, BIG_NEG);
942 intptr_t slice_len_con = (intptr_t) _igvn.find_int_con(slice_len, BIG_NEG);
943 if (slice_len_con == 0) {
944 return; // nothing to do here
945 }
946 intptr_t start_con = (abase + (slice_idx_con << scale)) & ~clear_low;
947 intptr_t end_con = _igvn.find_intptr_t_con(dest_size, -1);
948 if (slice_idx_con >= 0 && slice_len_con >= 0) {
949 assert(end_con < 0, "not two cons");
950 end_con = align_up(abase + ((slice_idx_con + slice_len_con) << scale),
951 BytesPerLong);
952 }
953
954 if (start_con >= 0 && end_con >= 0) {
955 // Constant start and end. Simple.
956 mem = ClearArrayNode::clear_memory(ctrl, mem, dest, val, raw_val,
957 start_con, end_con, &_igvn);
958 } else if (start_con >= 0 && dest_size != top()) {
959 // Constant start, pre-rounded end after the tail of the array.
960 Node* end = dest_size;
961 mem = ClearArrayNode::clear_memory(ctrl, mem, dest, val, raw_val,
962 start_con, end, &_igvn);
963 } else if (start_con >= 0 && slice_len != top()) {
964 // Constant start, non-constant end. End needs rounding up.
965 // End offset = round_up(abase + ((slice_idx_con + slice_len) << scale), 8)
966 intptr_t end_base = abase + (slice_idx_con << scale);
967 int end_round = (-1 << scale) & (BytesPerLong - 1);
968 Node* end = ConvI2X(slice_len);
969 if (scale != 0)
970 end = transform_later(new LShiftXNode(end, intcon(scale) ));
971 end_base += end_round;
972 end = transform_later(new AddXNode(end, MakeConX(end_base)) );
973 end = transform_later(new AndXNode(end, MakeConX(~end_round)) );
974 mem = ClearArrayNode::clear_memory(ctrl, mem, dest, val, raw_val,
975 start_con, end, &_igvn);
976 } else if (start_con < 0 && dest_size != top()) {
977 // Non-constant start, pre-rounded end after the tail of the array.
978 // This is almost certainly a "round-to-end" operation.
979 Node* start = slice_idx;
980 start = ConvI2X(start);
981 if (scale != 0)
982 start = transform_later(new LShiftXNode( start, intcon(scale) ));
983 start = transform_later(new AddXNode(start, MakeConX(abase)) );
984 if ((bump_bit | clear_low) != 0) {
985 int to_clear = (bump_bit | clear_low);
986 // Align up mod 8, then store a jint zero unconditionally
987 // just before the mod-8 boundary.
988 if (((abase + bump_bit) & ~to_clear) - bump_bit
989 < arrayOopDesc::length_offset_in_bytes() + BytesPerInt) {
990 bump_bit = 0;
991 assert((abase & to_clear) == 0, "array base must be long-aligned");
992 } else {
993 // Bump 'start' up to (or past) the next jint boundary:
994 start = transform_later( new AddXNode(start, MakeConX(bump_bit)) );
995 assert((abase & clear_low) == 0, "array base must be int-aligned");
996 }
997 // Round bumped 'start' down to jlong boundary in body of array.
998 start = transform_later(new AndXNode(start, MakeConX(~to_clear)) );
999 if (bump_bit != 0) {
1000 // Store a zero to the immediately preceding jint:
1001 Node* x1 = transform_later(new AddXNode(start, MakeConX(-bump_bit)) );
1002 Node* p1 = basic_plus_adr(dest, x1);
1003 if (val == NULL) {
1004 assert(raw_val == NULL, "val may not be null");
1005 mem = StoreNode::make(_igvn, ctrl, mem, p1, adr_type, intcon(0), T_INT, MemNode::unordered);
1006 } else {
1007 assert(_igvn.type(val)->isa_narrowoop(), "should be narrow oop");
1008 mem = new StoreNNode(ctrl, mem, p1, adr_type, val, MemNode::unordered);
1009 }
1010 mem = transform_later(mem);
1011 }
1012 }
1013 Node* end = dest_size; // pre-rounded
1014 mem = ClearArrayNode::clear_memory(ctrl, mem, dest, raw_val,
1015 start, end, &_igvn);
1016 } else {
1017 // Non-constant start, unrounded non-constant end.
1018 // (Nobody zeroes a random midsection of an array using this routine.)
1019 ShouldNotReachHere(); // fix caller
1020 }
1021
1022 // Done.
1023 merge_mem->set_memory_at(alias_idx, mem);
1024 }
1025
1026 bool PhaseMacroExpand::generate_block_arraycopy(Node** ctrl, MergeMemNode** mem, Node* io,
1027 const TypePtr* adr_type,
1028 BasicType basic_elem_type,
1029 AllocateNode* alloc,
1030 Node* src, Node* src_offset,
1031 Node* dest, Node* dest_offset,
1032 Node* dest_size, bool dest_uninitialized) {
1033 // See if there is an advantage from block transfer.
1034 int scale = exact_log2(type2aelembytes(basic_elem_type));
1035 if (scale >= LogBytesPerLong)
1036 return false; // it is already a block transfer
1037
1038 // Look at the alignment of the starting offsets.
1039 int abase = arrayOopDesc::base_offset_in_bytes(basic_elem_type);
1040
1041 intptr_t src_off_con = (intptr_t) _igvn.find_int_con(src_offset, -1);
1042 intptr_t dest_off_con = (intptr_t) _igvn.find_int_con(dest_offset, -1);
1043 if (src_off_con < 0 || dest_off_con < 0) {
1044 // At present, we can only understand constants.
1045 return false;
1046 }
1047
1048 intptr_t src_off = abase + (src_off_con << scale);
1049 intptr_t dest_off = abase + (dest_off_con << scale);
1050
1051 if (((src_off | dest_off) & (BytesPerLong-1)) != 0) {
1052 // Non-aligned; too bad.
1053 // One more chance: Pick off an initial 32-bit word.
1054 // This is a common case, since abase can be odd mod 8.
1055 if (((src_off | dest_off) & (BytesPerLong-1)) == BytesPerInt &&
1056 ((src_off ^ dest_off) & (BytesPerLong-1)) == 0) {
1057 Node* sptr = basic_plus_adr(src, src_off);
1058 Node* dptr = basic_plus_adr(dest, dest_off);
1059 const TypePtr* s_adr_type = _igvn.type(sptr)->is_ptr();
1060 assert(s_adr_type->isa_aryptr(), "impossible slice");
1061 uint s_alias_idx = C->get_alias_index(s_adr_type);
1062 uint d_alias_idx = C->get_alias_index(adr_type);
1063 bool is_mismatched = (basic_elem_type != T_INT);
1064 Node* sval = transform_later(
1065 LoadNode::make(_igvn, *ctrl, (*mem)->memory_at(s_alias_idx), sptr, s_adr_type,
1066 TypeInt::INT, T_INT, MemNode::unordered, LoadNode::DependsOnlyOnTest,
1067 false /*require_atomic_access*/, false /*unaligned*/, is_mismatched));
1068 Node* st = transform_later(
1069 StoreNode::make(_igvn, *ctrl, (*mem)->memory_at(d_alias_idx), dptr, adr_type,
1070 sval, T_INT, MemNode::unordered));
1071 if (is_mismatched) {
1072 st->as_Store()->set_mismatched_access();
1073 }
1074 (*mem)->set_memory_at(d_alias_idx, st);
1075 src_off += BytesPerInt;
1076 dest_off += BytesPerInt;
1077 } else {
1078 return false;
1079 }
1080 }
1081 assert(src_off % BytesPerLong == 0, "");
1082 assert(dest_off % BytesPerLong == 0, "");
1083
1084 // Do this copy by giant steps.
1085 Node* sptr = basic_plus_adr(src, src_off);
1086 Node* dptr = basic_plus_adr(dest, dest_off);
1087 Node* countx = dest_size;
1088 countx = transform_later(new SubXNode(countx, MakeConX(dest_off)));
1089 countx = transform_later(new URShiftXNode(countx, intcon(LogBytesPerLong)));
1090
1091 bool disjoint_bases = true; // since alloc != NULL
1092 generate_unchecked_arraycopy(ctrl, mem,
1093 adr_type, T_LONG, disjoint_bases,
1094 sptr, NULL, dptr, NULL, countx, dest_uninitialized);
1095
1096 return true;
1097 }
1098
1099 // Helper function; generates code for the slow case.
1100 // We make a call to a runtime method which emulates the native method,
1101 // but without the native wrapper overhead.
1102 MergeMemNode* PhaseMacroExpand::generate_slow_arraycopy(ArrayCopyNode *ac,
1103 Node** ctrl, Node* mem, Node** io,
1104 const TypePtr* adr_type,
1105 Node* src, Node* src_offset,
1106 Node* dest, Node* dest_offset,
1107 Node* copy_length, bool dest_uninitialized) {
1108 assert(!dest_uninitialized, "Invariant");
1109
1110 const TypeFunc* call_type = OptoRuntime::slow_arraycopy_Type();
1111 CallNode* call = new CallStaticJavaNode(call_type, OptoRuntime::slow_arraycopy_Java(),
1112 "slow_arraycopy", TypePtr::BOTTOM);
1113
1114 call->init_req(TypeFunc::Control, *ctrl);
1115 call->init_req(TypeFunc::I_O , *io);
1116 call->init_req(TypeFunc::Memory , mem);
1117 call->init_req(TypeFunc::ReturnAdr, top());
1118 call->init_req(TypeFunc::FramePtr, top());
1119 call->init_req(TypeFunc::Parms+0, src);
1120 call->init_req(TypeFunc::Parms+1, src_offset);
1121 call->init_req(TypeFunc::Parms+2, dest);
1122 call->init_req(TypeFunc::Parms+3, dest_offset);
1123 call->init_req(TypeFunc::Parms+4, copy_length);
1124 call->copy_call_debug_info(&_igvn, ac);
1125
1126 call->set_cnt(PROB_UNLIKELY_MAG(4)); // Same effect as RC_UNCOMMON.
1127 _igvn.replace_node(ac, call);
1128 transform_later(call);
1129
1130 _callprojs = call->extract_projections(false /*separate_io_proj*/, false /*do_asserts*/);
1131 *ctrl = _callprojs->fallthrough_catchproj->clone();
1132 transform_later(*ctrl);
1133
1134 Node* m = _callprojs->fallthrough_memproj->clone();
1135 transform_later(m);
1136
1137 uint alias_idx = C->get_alias_index(adr_type);
1138 MergeMemNode* out_mem;
1139 if (alias_idx != Compile::AliasIdxBot) {
1140 out_mem = MergeMemNode::make(mem);
1141 out_mem->set_memory_at(alias_idx, m);
1142 } else {
1143 out_mem = MergeMemNode::make(m);
1144 }
1145 transform_later(out_mem);
1146
1147 // When src is negative and arraycopy is before an infinite loop,_callprojs.fallthrough_ioproj
1148 // could be NULL. Skip clone and update NULL fallthrough_ioproj.
1149 if (_callprojs->fallthrough_ioproj != NULL) {
1150 *io = _callprojs->fallthrough_ioproj->clone();
1151 transform_later(*io);
1152 } else {
1153 *io = NULL;
1154 }
1155
1156 return out_mem;
1157 }
1158
1159 // Helper function; generates code for cases requiring runtime checks.
1160 Node* PhaseMacroExpand::generate_checkcast_arraycopy(Node** ctrl, MergeMemNode** mem,
1161 const TypePtr* adr_type,
1162 Node* dest_elem_klass,
1163 Node* src, Node* src_offset,
1164 Node* dest, Node* dest_offset,
1165 Node* copy_length, bool dest_uninitialized) {
1166 if ((*ctrl)->is_top()) return NULL;
1167
1168 address copyfunc_addr = StubRoutines::checkcast_arraycopy(dest_uninitialized);
1169 if (copyfunc_addr == NULL) { // Stub was not generated, go slow path.
1170 return NULL;
1171 }
1172
1173 // Pick out the parameters required to perform a store-check
1174 // for the target array. This is an optimistic check. It will
1175 // look in each non-null element's class, at the desired klass's
1176 // super_check_offset, for the desired klass.
1177 int sco_offset = in_bytes(Klass::super_check_offset_offset());
1178 Node* p3 = basic_plus_adr(dest_elem_klass, sco_offset);
1179 Node* n3 = new LoadINode(NULL, *mem /*memory(p3)*/, p3, _igvn.type(p3)->is_ptr(), TypeInt::INT, MemNode::unordered);
1180 Node* check_offset = ConvI2X(transform_later(n3));
1181 Node* check_value = dest_elem_klass;
1182
1183 Node* src_start = array_element_address(src, src_offset, T_OBJECT);
1184 Node* dest_start = array_element_address(dest, dest_offset, T_OBJECT);
1185
1186 const TypeFunc* call_type = OptoRuntime::checkcast_arraycopy_Type();
1187 Node* call = make_leaf_call(*ctrl, *mem, call_type, copyfunc_addr, "checkcast_arraycopy", adr_type,
1188 src_start, dest_start, copy_length XTOP, check_offset XTOP, check_value);
1189
1190 finish_arraycopy_call(call, ctrl, mem, adr_type);
1191
1192 Node* proj = new ProjNode(call, TypeFunc::Parms);
1193 transform_later(proj);
1194
1195 return proj;
1196 }
1197
1198 // Helper function; generates code for cases requiring runtime checks.
1199 Node* PhaseMacroExpand::generate_generic_arraycopy(Node** ctrl, MergeMemNode** mem,
1200 const TypePtr* adr_type,
1201 Node* src, Node* src_offset,
1202 Node* dest, Node* dest_offset,
1203 Node* copy_length, bool dest_uninitialized) {
1204 if ((*ctrl)->is_top()) return NULL;
1205 assert(!dest_uninitialized, "Invariant");
1206
1207 address copyfunc_addr = StubRoutines::generic_arraycopy();
1208 if (copyfunc_addr == NULL) { // Stub was not generated, go slow path.
1209 return NULL;
1210 }
1211
1212 const TypeFunc* call_type = OptoRuntime::generic_arraycopy_Type();
1213 Node* call = make_leaf_call(*ctrl, *mem, call_type, copyfunc_addr, "generic_arraycopy", adr_type,
1214 src, src_offset, dest, dest_offset, copy_length);
1215
1216 finish_arraycopy_call(call, ctrl, mem, adr_type);
1217
1218 Node* proj = new ProjNode(call, TypeFunc::Parms);
1219 transform_later(proj);
1220
1221 return proj;
1222 }
1223
1224 // Helper function; generates the fast out-of-line call to an arraycopy stub.
1225 bool PhaseMacroExpand::generate_unchecked_arraycopy(Node** ctrl, MergeMemNode** mem,
1226 const TypePtr* adr_type,
1227 BasicType basic_elem_type,
1228 bool disjoint_bases,
1229 Node* src, Node* src_offset,
1230 Node* dest, Node* dest_offset,
1231 Node* copy_length, bool dest_uninitialized) {
1232 if ((*ctrl)->is_top()) return false;
1233
1234 Node* src_start = src;
1235 Node* dest_start = dest;
1236 if (src_offset != NULL || dest_offset != NULL) {
1237 src_start = array_element_address(src, src_offset, basic_elem_type);
1238 dest_start = array_element_address(dest, dest_offset, basic_elem_type);
1239 }
1240
1241 // Figure out which arraycopy runtime method to call.
1242 const char* copyfunc_name = "arraycopy";
1243 address copyfunc_addr =
1244 basictype2arraycopy(basic_elem_type, src_offset, dest_offset,
1245 disjoint_bases, copyfunc_name, dest_uninitialized);
1246
1247 Node* result_memory = NULL;
1248 RegionNode* exit_block = NULL;
1249 if (ArrayOperationPartialInlineSize > 0 && is_subword_type(basic_elem_type) &&
1250 Matcher::vector_width_in_bytes(basic_elem_type) >= 16) {
1251 generate_partial_inlining_block(ctrl, mem, adr_type, &exit_block, &result_memory,
1252 copy_length, src_start, dest_start, basic_elem_type);
1253 }
1254
1255 const TypeFunc* call_type = OptoRuntime::fast_arraycopy_Type();
1256 Node* call = make_leaf_call(*ctrl, *mem, call_type, copyfunc_addr, copyfunc_name, adr_type,
1257 src_start, dest_start, copy_length XTOP);
1258
1259 finish_arraycopy_call(call, ctrl, mem, adr_type);
1260
1261 // Connecting remaining edges for exit_block coming from stub_block.
1262 if (exit_block) {
1263 exit_block->init_req(2, *ctrl);
1264
1265 // Memory edge corresponding to stub_region.
1266 result_memory->init_req(2, *mem);
1267
1268 uint alias_idx = C->get_alias_index(adr_type);
1269 if (alias_idx != Compile::AliasIdxBot) {
1270 *mem = MergeMemNode::make(*mem);
1271 (*mem)->set_memory_at(alias_idx, result_memory);
1272 } else {
1273 *mem = MergeMemNode::make(result_memory);
1274 }
1275 transform_later(*mem);
1276 *ctrl = exit_block;
1277 return true;
1278 }
1279 return false;
1280 }
1281
1282 const TypePtr* PhaseMacroExpand::adjust_for_flat_array(const TypeAryPtr* top_dest, Node*& src_offset,
1283 Node*& dest_offset, Node*& length, BasicType& dest_elem,
1284 Node*& dest_length) {
1285 #ifdef ASSERT
1286 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1287 bool needs_barriers = top_dest->elem()->inline_klass()->contains_oops() &&
1288 bs->array_copy_requires_gc_barriers(dest_length != NULL, T_OBJECT, false, false, BarrierSetC2::Optimization);
1289 assert(!needs_barriers || StressReflectiveCode, "Flat arracopy would require GC barriers");
1290 #endif
1291 int elem_size = top_dest->flat_elem_size();
1292 if (elem_size >= 8) {
1293 if (elem_size > 8) {
1294 // treat as array of long but scale length, src offset and dest offset
1295 assert((elem_size % 8) == 0, "not a power of 2?");
1296 int factor = elem_size / 8;
1297 length = transform_later(new MulINode(length, intcon(factor)));
1298 src_offset = transform_later(new MulINode(src_offset, intcon(factor)));
1299 dest_offset = transform_later(new MulINode(dest_offset, intcon(factor)));
1300 if (dest_length != NULL) {
1301 dest_length = transform_later(new MulINode(dest_length, intcon(factor)));
1302 }
1303 elem_size = 8;
1304 }
1305 dest_elem = T_LONG;
1306 } else if (elem_size == 4) {
1307 dest_elem = T_INT;
1308 } else if (elem_size == 2) {
1309 dest_elem = T_CHAR;
1310 } else if (elem_size == 1) {
1311 dest_elem = T_BYTE;
1312 } else {
1313 ShouldNotReachHere();
1314 }
1315 return TypeRawPtr::BOTTOM;
1316 }
1317
1318 #undef XTOP
1319
1320 void PhaseMacroExpand::expand_arraycopy_node(ArrayCopyNode *ac) {
1321 Node* ctrl = ac->in(TypeFunc::Control);
1322 Node* io = ac->in(TypeFunc::I_O);
1323 Node* src = ac->in(ArrayCopyNode::Src);
1324 Node* src_offset = ac->in(ArrayCopyNode::SrcPos);
1325 Node* dest = ac->in(ArrayCopyNode::Dest);
1326 Node* dest_offset = ac->in(ArrayCopyNode::DestPos);
1327 Node* length = ac->in(ArrayCopyNode::Length);
1328 MergeMemNode* merge_mem = NULL;
1329
1330 if (ac->is_clonebasic()) {
1331 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1332 bs->clone_at_expansion(this, ac);
1333 return;
1334 } else if (ac->is_copyof() || ac->is_copyofrange() || ac->is_clone_oop_array()) {
1335 const Type* src_type = _igvn.type(src);
1336 const Type* dest_type = _igvn.type(dest);
1337 const TypeAryPtr* top_src = src_type->isa_aryptr();
1338 const TypeAryPtr* top_dest = dest_type->isa_aryptr();
1339 BasicType dest_elem = T_OBJECT;
1340 if (top_dest != NULL && top_dest->elem() != Type::BOTTOM) {
1341 dest_elem = top_dest->elem()->array_element_basic_type();
1342 }
1343 if (is_reference_type(dest_elem, true)) dest_elem = T_OBJECT;
1344
1345 if (top_src != NULL && top_src->is_flat()) {
1346 // If src is flat, dest is guaranteed to be flat as well
1347 top_dest = top_src;
1348 }
1349
1350 AllocateArrayNode* alloc = NULL;
1351 Node* dest_length = NULL;
1352 if (ac->is_alloc_tightly_coupled()) {
1353 alloc = AllocateArrayNode::Ideal_array_allocation(dest, &_igvn);
1354 assert(alloc != NULL, "expect alloc");
1355 dest_length = alloc->in(AllocateNode::ALength);
1356 }
1357
1358 Node* mem = ac->in(TypeFunc::Memory);
1359 const TypePtr* adr_type = NULL;
1360 if (top_dest->is_flat()) {
1361 assert(dest_length != NULL || StressReflectiveCode, "must be tightly coupled");
1362 // Copy to a flat array modifies multiple memory slices. Conservatively insert a barrier
1363 // on all slices to prevent writes into the source from floating below the arraycopy.
1364 insert_mem_bar(&ctrl, &mem, Op_MemBarCPUOrder);
1365 adr_type = adjust_for_flat_array(top_dest, src_offset, dest_offset, length, dest_elem, dest_length);
1366 } else {
1367 adr_type = dest_type->is_oopptr()->add_offset(Type::OffsetBot);
1368 if (ac->_dest_type != TypeOopPtr::BOTTOM) {
1369 adr_type = ac->_dest_type->add_offset(Type::OffsetBot)->is_ptr();
1370 }
1371 if (ac->_src_type != ac->_dest_type) {
1372 adr_type = TypeRawPtr::BOTTOM;
1373 }
1374 }
1375 merge_mem = MergeMemNode::make(mem);
1376 transform_later(merge_mem);
1377
1378 generate_arraycopy(ac, alloc, &ctrl, merge_mem, &io,
1379 adr_type, dest_elem,
1380 src, src_offset, dest, dest_offset, length,
1381 dest_length,
1382 true, !ac->is_copyofrange());
1383 return;
1384 }
1385
1386 AllocateArrayNode* alloc = NULL;
1387 if (ac->is_alloc_tightly_coupled()) {
1388 alloc = AllocateArrayNode::Ideal_array_allocation(dest, &_igvn);
1389 assert(alloc != NULL, "expect alloc");
1390 }
1391
1392 assert(ac->is_arraycopy() || ac->is_arraycopy_validated(), "should be an arraycopy");
1393
1394 // Compile time checks. If any of these checks cannot be verified at compile time,
1395 // we do not make a fast path for this call. Instead, we let the call remain as it
1396 // is. The checks we choose to mandate at compile time are:
1397 //
1398 // (1) src and dest are arrays.
1399 const Type* src_type = src->Value(&_igvn);
1400 const Type* dest_type = dest->Value(&_igvn);
1401 const TypeAryPtr* top_src = src_type->isa_aryptr();
1402 const TypeAryPtr* top_dest = dest_type->isa_aryptr();
1403
1404 BasicType src_elem = T_CONFLICT;
1405 BasicType dest_elem = T_CONFLICT;
1406
1407 if (top_src != NULL && top_src->elem() != Type::BOTTOM) {
1408 src_elem = top_src->elem()->array_element_basic_type();
1409 }
1410 if (top_dest != NULL && top_dest->elem() != Type::BOTTOM) {
1411 dest_elem = top_dest->elem()->array_element_basic_type();
1412 }
1413 if (is_reference_type(src_elem, true)) src_elem = T_OBJECT;
1414 if (is_reference_type(dest_elem, true)) dest_elem = T_OBJECT;
1415
1416 if (ac->is_arraycopy_validated() && dest_elem != T_CONFLICT && src_elem == T_CONFLICT) {
1417 src_elem = dest_elem;
1418 }
1419
1420 if (src_elem == T_CONFLICT || dest_elem == T_CONFLICT) {
1421 // Conservatively insert a memory barrier on all memory slices.
1422 // Do not let writes into the source float below the arraycopy.
1423 {
1424 Node* mem = ac->in(TypeFunc::Memory);
1425 insert_mem_bar(&ctrl, &mem, Op_MemBarCPUOrder);
1426
1427 merge_mem = MergeMemNode::make(mem);
1428 transform_later(merge_mem);
1429 }
1430
1431 // Call StubRoutines::generic_arraycopy stub.
1432 Node* mem = generate_arraycopy(ac, NULL, &ctrl, merge_mem, &io,
1433 TypeRawPtr::BOTTOM, T_CONFLICT,
1434 src, src_offset, dest, dest_offset, length,
1435 NULL,
1436 // If a negative length guard was generated for the ArrayCopyNode,
1437 // the length of the array can never be negative.
1438 false, ac->has_negative_length_guard());
1439 return;
1440 }
1441
1442 assert(!ac->is_arraycopy_validated() || (src_elem == dest_elem && dest_elem != T_VOID), "validated but different basic types");
1443
1444 // (2) src and dest arrays must have elements of the same BasicType
1445 // Figure out the size and type of the elements we will be copying.
1446 //
1447 // We have no stub to copy flattened inline type arrays with oop
1448 // fields if we need to emit write barriers.
1449 //
1450 BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1451 if (src_elem != dest_elem || top_src->is_flat() != top_dest->is_flat() || dest_elem == T_VOID ||
1452 (top_src->is_flat() && top_dest->elem()->inline_klass()->contains_oops() &&
1453 bs->array_copy_requires_gc_barriers(alloc != NULL, T_OBJECT, false, false, BarrierSetC2::Optimization))) {
1454 // The component types are not the same or are not recognized. Punt.
1455 // (But, avoid the native method wrapper to JVM_ArrayCopy.)
1456 {
1457 Node* mem = ac->in(TypeFunc::Memory);
1458 merge_mem = generate_slow_arraycopy(ac, &ctrl, mem, &io, TypePtr::BOTTOM, src, src_offset, dest, dest_offset, length, false);
1459 }
1460
1461 _igvn.replace_node(_callprojs->fallthrough_memproj, merge_mem);
1462 if (_callprojs->fallthrough_ioproj != NULL) {
1463 _igvn.replace_node(_callprojs->fallthrough_ioproj, io);
1464 }
1465 _igvn.replace_node(_callprojs->fallthrough_catchproj, ctrl);
1466 return;
1467 }
1468
1469 //---------------------------------------------------------------------------
1470 // We will make a fast path for this call to arraycopy.
1471
1472 // We have the following tests left to perform:
1473 //
1474 // (3) src and dest must not be null.
1475 // (4) src_offset must not be negative.
1476 // (5) dest_offset must not be negative.
1477 // (6) length must not be negative.
1478 // (7) src_offset + length must not exceed length of src.
1479 // (8) dest_offset + length must not exceed length of dest.
1480 // (9) each element of an oop array must be assignable
1481
1482 Node* mem = ac->in(TypeFunc::Memory);
1483 if (top_dest->is_flat()) {
1484 // Copy to a flat array modifies multiple memory slices. Conservatively insert a barrier
1485 // on all slices to prevent writes into the source from floating below the arraycopy.
1486 insert_mem_bar(&ctrl, &mem, Op_MemBarCPUOrder);
1487 }
1488 merge_mem = MergeMemNode::make(mem);
1489 transform_later(merge_mem);
1490
1491 RegionNode* slow_region = new RegionNode(1);
1492 transform_later(slow_region);
1493
1494 if (!ac->is_arraycopy_validated()) {
1495 // (3) operands must not be null
1496 // We currently perform our null checks with the null_check routine.
1497 // This means that the null exceptions will be reported in the caller
1498 // rather than (correctly) reported inside of the native arraycopy call.
1499 // This should be corrected, given time. We do our null check with the
1500 // stack pointer restored.
1501 // null checks done library_call.cpp
1502
1503 // (4) src_offset must not be negative.
1504 generate_negative_guard(&ctrl, src_offset, slow_region);
1505
1506 // (5) dest_offset must not be negative.
1507 generate_negative_guard(&ctrl, dest_offset, slow_region);
1508
1509 // (6) length must not be negative (moved to generate_arraycopy()).
1510 // generate_negative_guard(length, slow_region);
1511
1512 // (7) src_offset + length must not exceed length of src.
1513 Node* alen = ac->in(ArrayCopyNode::SrcLen);
1514 assert(alen != NULL, "need src len");
1515 generate_limit_guard(&ctrl,
1516 src_offset, length,
1517 alen,
1518 slow_region);
1519
1520 // (8) dest_offset + length must not exceed length of dest.
1521 alen = ac->in(ArrayCopyNode::DestLen);
1522 assert(alen != NULL, "need dest len");
1523 generate_limit_guard(&ctrl,
1524 dest_offset, length,
1525 alen,
1526 slow_region);
1527
1528 // (9) each element of an oop array must be assignable
1529 // The generate_arraycopy subroutine checks this.
1530
1531 // Handle inline type arrays
1532 if (!top_src->is_flat()) {
1533 if (UseFlatArray && !top_src->is_not_flat()) {
1534 // Src might be flat and dest might not be flat. Go to the slow path if src is flat.
1535 generate_flat_array_guard(&ctrl, src, slow_region);
1536 }
1537 if (EnableValhalla) {
1538 // No validation. The subtype check emitted at macro expansion time will not go to the slow
1539 // path but call checkcast_arraycopy which can not handle flat/null-free inline type arrays.
1540 generate_null_free_array_guard(&ctrl, dest, slow_region);
1541 }
1542 } else {
1543 assert(top_dest->is_flat(), "dest array must be flat");
1544 }
1545 }
1546
1547 // This is where the memory effects are placed:
1548 const TypePtr* adr_type = NULL;
1549 Node* dest_length = (alloc != NULL) ? alloc->in(AllocateNode::ALength) : NULL;
1550
1551 if (top_dest->is_flat()) {
1552 adr_type = adjust_for_flat_array(top_dest, src_offset, dest_offset, length, dest_elem, dest_length);
1553 } else if (ac->_dest_type != TypeOopPtr::BOTTOM) {
1554 adr_type = ac->_dest_type->add_offset(Type::OffsetBot)->is_ptr();
1555 } else {
1556 adr_type = TypeAryPtr::get_array_body_type(dest_elem);
1557 }
1558
1559 generate_arraycopy(ac, alloc, &ctrl, merge_mem, &io,
1560 adr_type, dest_elem,
1561 src, src_offset, dest, dest_offset, length,
1562 dest_length,
1563 // If a negative length guard was generated for the ArrayCopyNode,
1564 // the length of the array can never be negative.
1565 false, ac->has_negative_length_guard(),
1566 slow_region);
1567 }