1 /*
2 * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "asm/codeBuffer.hpp"
26 #include "code/aotCodeCache.hpp"
27 #include "code/compiledIC.hpp"
28 #include "code/oopRecorder.inline.hpp"
29 #include "compiler/disassembler.hpp"
30 #include "logging/log.hpp"
31 #include "oops/klass.inline.hpp"
32 #include "oops/methodCounters.hpp"
33 #include "oops/methodData.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "runtime/safepointVerifiers.hpp"
36 #include "utilities/align.hpp"
37 #include "utilities/copy.hpp"
38 #include "utilities/powerOfTwo.hpp"
39 #include "utilities/xmlstream.hpp"
40
41 // The structure of a CodeSection:
42 //
43 // _start -> +----------------+
44 // | machine code...|
45 // _end -> |----------------|
46 // | |
47 // | (empty) |
48 // | |
49 // | |
50 // +----------------+
51 // _limit -> | |
52 //
53 // _locs_start -> +----------------+
54 // |reloc records...|
55 // |----------------|
56 // _locs_end -> | |
57 // | |
58 // | (empty) |
59 // | |
60 // | |
61 // +----------------+
62 // _locs_limit -> | |
63 // The _end (resp. _limit) pointer refers to the first
64 // unused (resp. unallocated) byte.
65
66 // The structure of the CodeBuffer while code is being accumulated:
67 //
68 // _total_start -> \
69 // _consts._start -> +----------------+
70 // | |
71 // | Constants |
72 // | |
73 // _insts._start -> |----------------|
74 // | |
75 // | Code |
76 // | |
77 // _stubs._start -> |----------------|
78 // | |
79 // | Stubs | (also handlers for deopt/exception)
80 // | |
81 // +----------------+
82 // + _total_size -> | |
83 //
84 // When the code and relocations are copied to the code cache,
85 // the empty parts of each section are removed, and everything
86 // is copied into contiguous locations.
87
88 typedef CodeBuffer::csize_t csize_t; // file-local definition
89
90 // External buffer, in a predefined CodeBlob.
91 // Important: The code_start must be taken exactly, and not realigned.
92 CodeBuffer::CodeBuffer(const CodeBlob* blob) DEBUG_ONLY(: Scrubber(this, sizeof(*this))) {
93 // Provide code buffer with meaningful name
94 initialize_misc(blob->name());
95 initialize(blob->content_begin(), blob->content_size());
96 DEBUG_ONLY(verify_section_allocation();)
97 }
98
99 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
100 MACOS_AARCH64_ONLY(os::thread_wx_enable_write());
101
102 // Always allow for empty slop around each section.
103 int slop = (int) CodeSection::end_slop();
104
105 assert(SECT_LIMIT == 3, "total_size explicitly lists all section alignments");
106 int total_size = code_size + _consts.alignment() + _insts.alignment() + _stubs.alignment() + SECT_LIMIT * slop;
107
108 assert(blob() == nullptr, "only once");
109 set_blob(BufferBlob::create(_name, total_size));
110 if (blob() == nullptr) {
111 // The assembler constructor will throw a fatal on an empty CodeBuffer.
112 return; // caller must test this
113 }
114
115 // Set up various pointers into the blob.
116 initialize(_total_start, _total_size);
117
118 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
119
120 pd_initialize();
121
122 if (locs_size != 0) {
123 _insts.initialize_locs(locs_size / sizeof(relocInfo));
124 }
125
126 DEBUG_ONLY(verify_section_allocation();)
127 }
128
129
130 CodeBuffer::~CodeBuffer() {
131 verify_section_allocation();
132
133 // If we allocated our code buffer from the CodeCache via a BufferBlob, and
134 // it's not permanent, then free the BufferBlob. The rest of the memory
135 // will be freed when the ResourceObj is released.
136 for (CodeBuffer* cb = this; cb != nullptr; cb = cb->before_expand()) {
137 // Previous incarnations of this buffer are held live, so that internal
138 // addresses constructed before expansions will not be confused.
139 cb->free_blob();
140 }
141 if (_overflow_arena != nullptr) {
142 // free any overflow storage
143 delete _overflow_arena;
144 }
145 if (_shared_trampoline_requests != nullptr) {
146 delete _shared_trampoline_requests;
147 }
148
149 NOT_PRODUCT(clear_strings());
150 }
151
152 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
153 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
154 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen
155 _oop_recorder = r;
156 }
157
158 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
159 assert(cs != &_insts, "insts is the memory provider, not the consumer");
160 csize_t slop = CodeSection::end_slop(); // margin between sections
161 int align = cs->alignment();
162 assert(is_power_of_2(align), "sanity");
163 address start = _insts._start;
164 address limit = _insts._limit;
165 address middle = limit - size;
166 middle -= (intptr_t)middle & (align-1); // align the division point downward
167 guarantee(middle - slop > start, "need enough space to divide up");
168 _insts._limit = middle - slop; // subtract desired space, plus slop
169 cs->initialize(middle, limit - middle);
170 assert(cs->start() == middle, "sanity");
171 assert(cs->limit() == limit, "sanity");
172 // give it some relocations to start with, if the main section has them
173 if (_insts.has_locs()) cs->initialize_locs(1);
174 }
175
176 void CodeBuffer::set_blob(BufferBlob* blob) {
177 _blob = blob;
178 if (blob != nullptr) {
179 address start = blob->content_begin();
180 address end = blob->content_end();
181 // Round up the starting address.
182 int align = _insts.alignment();
183 start += (-(intptr_t)start) & (align-1);
184 _total_start = start;
185 _total_size = end - start;
186 } else {
187 #ifdef ASSERT
188 // Clean out dangling pointers.
189 _total_start = badAddress;
190 _consts._start = _consts._end = badAddress;
191 _insts._start = _insts._end = badAddress;
192 _stubs._start = _stubs._end = badAddress;
193 #endif //ASSERT
194 }
195 }
196
197 void CodeBuffer::free_blob() {
198 if (_blob != nullptr) {
199 BufferBlob::free(_blob);
200 set_blob(nullptr);
201 }
202 }
203
204 const char* CodeBuffer::code_section_name(int n) {
205 #ifdef PRODUCT
206 return nullptr;
207 #else //PRODUCT
208 switch (n) {
209 case SECT_CONSTS: return "consts";
210 case SECT_INSTS: return "insts";
211 case SECT_STUBS: return "stubs";
212 default: return nullptr;
213 }
214 #endif //PRODUCT
215 }
216
217 int CodeBuffer::section_index_of(address addr) const {
218 for (int n = 0; n < (int)SECT_LIMIT; n++) {
219 const CodeSection* cs = code_section(n);
220 if (cs->allocates(addr)) return n;
221 }
222 return SECT_NONE;
223 }
224
225 int CodeBuffer::locator(address addr) const {
226 for (int n = 0; n < (int)SECT_LIMIT; n++) {
227 const CodeSection* cs = code_section(n);
228 if (cs->allocates(addr)) {
229 return locator(addr - cs->start(), n);
230 }
231 }
232 return -1;
233 }
234
235
236 bool CodeBuffer::is_backward_branch(Label& L) {
237 return L.is_bound() && insts_end() <= locator_address(L.loc());
238 }
239
240 #ifndef PRODUCT
241 address CodeBuffer::decode_begin() {
242 address begin = _insts.start();
243 if (_decode_begin != nullptr && _decode_begin > begin)
244 begin = _decode_begin;
245 return begin;
246 }
247 #endif // !PRODUCT
248
249 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
250 if (_overflow_arena == nullptr) {
251 _overflow_arena = new (mtCode) Arena(mtCode);
252 }
253 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
254 }
255
256
257 // Helper function for managing labels and their target addresses.
258 // Returns a sensible address, and if it is not the label's final
259 // address, notes the dependency (at 'branch_pc') on the label.
260 address CodeSection::target(Label& L, address branch_pc) {
261 if (L.is_bound()) {
262 int loc = L.loc();
263 if (index() == CodeBuffer::locator_sect(loc)) {
264 return start() + CodeBuffer::locator_pos(loc);
265 } else {
266 return outer()->locator_address(loc);
267 }
268 } else {
269 assert(allocates2(branch_pc), "sanity");
270 address base = start();
271 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
272 L.add_patch_at(outer(), patch_loc);
273
274 // Need to return a pc, doesn't matter what it is since it will be
275 // replaced during resolution later.
276 // Don't return null or badAddress, since branches shouldn't overflow.
277 // Don't return base either because that could overflow displacements
278 // for shorter branches. It will get checked when bound.
279 return branch_pc;
280 }
281 }
282
283 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) {
284 RelocationHolder rh;
285 switch (rtype) {
286 case relocInfo::none: return;
287 case relocInfo::opt_virtual_call_type: {
288 rh = opt_virtual_call_Relocation::spec(method_index);
289 break;
290 }
291 case relocInfo::static_call_type: {
292 rh = static_call_Relocation::spec(method_index);
293 break;
294 }
295 case relocInfo::virtual_call_type: {
296 assert(method_index == 0, "resolved method overriding is not supported");
297 rh = Relocation::spec_simple(rtype);
298 break;
299 }
300 default: {
301 rh = Relocation::spec_simple(rtype);
302 break;
303 }
304 }
305 relocate(at, rh, format);
306 }
307
308 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
309 // Do not relocate in scratch buffers.
310 if (scratch_emit()) { return; }
311 Relocation* reloc = spec.reloc();
312 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
313 if (rtype == relocInfo::none) return;
314
315 // The assertion below has been adjusted, to also work for
316 // relocation for fixup. Sometimes we want to put relocation
317 // information for the next instruction, since it will be patched
318 // with a call.
319 assert(start() <= at && at <= end()+1,
320 "cannot relocate data outside code boundaries");
321
322 if (!has_locs()) {
323 // no space for relocation information provided => code cannot be
324 // relocated. Make sure that relocate is only called with rtypes
325 // that can be ignored for this kind of code.
326 assert(rtype == relocInfo::none ||
327 rtype == relocInfo::runtime_call_type ||
328 rtype == relocInfo::internal_word_type||
329 rtype == relocInfo::section_word_type ||
330 rtype == relocInfo::external_word_type||
331 rtype == relocInfo::barrier_type ||
332 rtype == relocInfo::patchable_barrier_type,
333 "code needs relocation information");
334 // leave behind an indication that we attempted a relocation
335 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
336 return;
337 }
338
339 // Advance the point, noting the offset we'll have to record.
340 csize_t offset = at - locs_point();
341 set_locs_point(at);
342
343 // Test for a couple of overflow conditions; maybe expand the buffer.
344 relocInfo* end = locs_end();
345 relocInfo* req = end + relocInfo::length_limit;
346 // Check for (potential) overflow
347 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
348 req += (uint)offset / (uint)relocInfo::offset_limit();
349 if (req >= locs_limit()) {
350 // Allocate or reallocate.
351 expand_locs(locs_count() + (req - end));
352 // reload pointer
353 end = locs_end();
354 }
355 }
356
357 // If the offset is giant, emit filler relocs, of type 'none', but
358 // each carrying the largest possible offset, to advance the locs_point.
359 while (offset >= relocInfo::offset_limit()) {
360 assert(end < locs_limit(), "adjust previous paragraph of code");
361 *end++ = relocInfo::filler_info();
362 offset -= relocInfo::filler_info().addr_offset();
363 }
364
365 // If it's a simple reloc with no data, we'll just write (rtype | offset).
366 (*end) = relocInfo(rtype, offset, format);
367
368 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
369 end->initialize(this, reloc);
370 }
371
372 void CodeSection::initialize_locs(int locs_capacity) {
373 assert(_locs_start == nullptr, "only one locs init step, please");
374 // Apply a priori lower limits to relocation size:
375 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
376 if (locs_capacity < min_locs) locs_capacity = min_locs;
377 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
378 _locs_start = locs_start;
379 _locs_end = locs_start;
380 _locs_limit = locs_start + locs_capacity;
381 _locs_own = true;
382 }
383
384 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
385 assert(_locs_start == nullptr, "do this before locs are allocated");
386 // Internal invariant: locs buf must be fully aligned.
387 // See copy_relocations_to() below.
388 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
389 ++buf; --length;
390 }
391 if (length > 0) {
392 _locs_start = buf;
393 _locs_end = buf;
394 _locs_limit = buf + length;
395 _locs_own = false;
396 }
397 }
398
399 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
400 int lcount = source_cs->locs_count();
401 if (lcount != 0) {
402 initialize_shared_locs(source_cs->locs_start(), lcount);
403 _locs_end = _locs_limit = _locs_start + lcount;
404 assert(is_allocated(), "must have copied code already");
405 set_locs_point(start() + source_cs->locs_point_off());
406 }
407 assert(this->locs_count() == source_cs->locs_count(), "sanity");
408 }
409
410 void CodeSection::expand_locs(int new_capacity) {
411 if (_locs_start == nullptr) {
412 initialize_locs(new_capacity);
413 return;
414 } else {
415 int old_count = locs_count();
416 int old_capacity = locs_capacity();
417 if (new_capacity < old_capacity * 2)
418 new_capacity = old_capacity * 2;
419 relocInfo* locs_start;
420 if (_locs_own) {
421 locs_start = REALLOC_RESOURCE_ARRAY(_locs_start, old_capacity, new_capacity);
422 } else {
423 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
424 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
425 _locs_own = true;
426 }
427 _locs_start = locs_start;
428 _locs_end = locs_start + old_count;
429 _locs_limit = locs_start + new_capacity;
430 }
431 }
432
433 int CodeSection::alignment() const {
434 if (_index == CodeBuffer::SECT_CONSTS) {
435 // CodeBuffer controls the alignment of the constants section
436 return _outer->_const_section_alignment;
437 }
438 if (_index == CodeBuffer::SECT_INSTS) {
439 return (int) CodeEntryAlignment;
440 }
441 if (_index == CodeBuffer::SECT_STUBS) {
442 // CodeBuffer installer expects sections to be HeapWordSize aligned
443 return HeapWordSize;
444 }
445 ShouldNotReachHere();
446 return 0;
447 }
448
449 /// Support for emitting the code to its final location.
450 /// The pattern is the same for all functions.
451 /// We iterate over all the sections, padding each to alignment.
452
453 csize_t CodeBuffer::total_content_size() const {
454 csize_t size_so_far = 0;
455 for (int n = 0; n < (int)SECT_LIMIT; n++) {
456 const CodeSection* cs = code_section(n);
457 if (cs->is_empty()) continue; // skip trivial section
458 size_so_far = cs->align_at_start(size_so_far);
459 size_so_far += cs->size();
460 }
461 return size_so_far;
462 }
463
464 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
465 address buf = dest->_total_start;
466 csize_t buf_offset = 0;
467 assert(dest->_total_size >= total_content_size(), "must be big enough");
468 assert(!_finalize_stubs, "non-finalized stubs");
469
470 {
471 assert( (dest->_total_start - _insts.start()) % CodeEntryAlignment == 0, "copy must preserve alignment");
472 }
473
474 const CodeSection* prev_cs = nullptr;
475 CodeSection* prev_dest_cs = nullptr;
476
477 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
478 // figure compact layout of each section
479 const CodeSection* cs = code_section(n);
480 csize_t csize = cs->size();
481
482 CodeSection* dest_cs = dest->code_section(n);
483 if (!cs->is_empty()) {
484 // Compute initial padding; assign it to the previous non-empty guy.
485 // Cf. figure_expanded_capacities.
486 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
487 if (prev_dest_cs != nullptr) {
488 if (padding != 0) {
489 buf_offset += padding;
490 prev_dest_cs->_limit += padding;
491 }
492 } else {
493 guarantee(padding == 0, "In first iteration no padding should be needed.");
494 }
495 prev_dest_cs = dest_cs;
496 prev_cs = cs;
497 }
498
499 DEBUG_ONLY(dest_cs->_start = nullptr); // defeat double-initialization assert
500 dest_cs->initialize(buf+buf_offset, csize);
501 dest_cs->set_end(buf+buf_offset+csize);
502 assert(dest_cs->is_allocated(), "must always be allocated");
503 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
504
505 buf_offset += csize;
506 }
507
508 // Done calculating sections; did it come out to the right end?
509 assert(buf_offset == total_content_size(), "sanity");
510 DEBUG_ONLY(dest->verify_section_allocation();)
511 }
512
513 // Append an oop reference that keeps the class alive.
514 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) {
515 oop cl = k->klass_holder();
516 if (cl != nullptr && !oops->contains(cl)) {
517 oops->append(cl);
518 }
519 }
520
521 void CodeBuffer::finalize_oop_references(const methodHandle& mh) {
522 NoSafepointVerifier nsv;
523
524 GrowableArray<oop> oops;
525
526 // Make sure that immediate metadata records something in the OopRecorder
527 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
528 // pull code out of each section
529 CodeSection* cs = code_section(n);
530 if (cs->is_empty() || (cs->locs_count() == 0)) continue; // skip trivial section
531 RelocIterator iter(cs);
532 while (iter.next()) {
533 if (iter.type() == relocInfo::metadata_type) {
534 metadata_Relocation* md = iter.metadata_reloc();
535 if (md->metadata_is_immediate()) {
536 Metadata* m = md->metadata_value();
537 if (oop_recorder()->is_real(m)) {
538 if (m->is_methodData()) {
539 m = ((MethodData*)m)->method();
540 }
541 if (m->is_methodCounters()) {
542 m = ((MethodCounters*)m)->method();
543 }
544 if (m->is_method()) {
545 m = ((Method*)m)->method_holder();
546 }
547 if (m->is_klass()) {
548 append_oop_references(&oops, (Klass*)m);
549 } else {
550 // XXX This will currently occur for MDO which don't
551 // have a backpointer. This has to be fixed later.
552 m->print();
553 ShouldNotReachHere();
554 }
555 }
556 }
557 }
558 }
559 }
560
561 if (!oop_recorder()->is_unused()) {
562 for (int i = 0; i < oop_recorder()->metadata_count(); i++) {
563 Metadata* m = oop_recorder()->metadata_at(i);
564 if (oop_recorder()->is_real(m)) {
565 if (m->is_methodData()) {
566 m = ((MethodData*)m)->method();
567 }
568 if (m->is_methodCounters()) {
569 m = ((MethodCounters*)m)->method();
570 }
571 if (m->is_method()) {
572 m = ((Method*)m)->method_holder();
573 }
574 if (m->is_klass()) {
575 append_oop_references(&oops, (Klass*)m);
576 } else {
577 m->print();
578 ShouldNotReachHere();
579 }
580 }
581 }
582
583 }
584
585 // Add the class loader of Method* for the nmethod itself
586 append_oop_references(&oops, mh->method_holder());
587
588 // Add any oops that we've found
589 Thread* thread = Thread::current();
590 for (int i = 0; i < oops.length(); i++) {
591 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i)));
592 }
593 }
594
595
596
597 csize_t CodeBuffer::total_offset_of(const CodeSection* cs) const {
598 csize_t size_so_far = 0;
599 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
600 const CodeSection* cur_cs = code_section(n);
601 if (!cur_cs->is_empty()) {
602 size_so_far = cur_cs->align_at_start(size_so_far);
603 }
604 if (cur_cs->index() == cs->index()) {
605 return size_so_far;
606 }
607 size_so_far += cur_cs->size();
608 }
609 ShouldNotReachHere();
610 return -1;
611 }
612
613 int CodeBuffer::total_skipped_instructions_size() const {
614 int total_skipped_size = 0;
615 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
616 const CodeSection* cur_cs = code_section(n);
617 if (!cur_cs->is_empty()) {
618 total_skipped_size += cur_cs->_skipped_instructions_size;
619 }
620 }
621 return total_skipped_size;
622 }
623
624 csize_t CodeBuffer::total_relocation_size() const {
625 csize_t total = copy_relocations_to(nullptr); // dry run only
626 return (csize_t) align_up(total, HeapWordSize);
627 }
628
629 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit) const {
630 csize_t buf_offset = 0;
631 csize_t code_end_so_far = 0;
632 csize_t code_point_so_far = 0;
633
634 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
635 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
636
637 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
638 // pull relocs out of each section
639 const CodeSection* cs = code_section(n);
640 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
641 if (cs->is_empty()) continue; // skip trivial section
642 relocInfo* lstart = cs->locs_start();
643 relocInfo* lend = cs->locs_end();
644 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
645 csize_t csize = cs->size();
646 code_end_so_far = cs->align_at_start(code_end_so_far);
647
648 if (lsize > 0) {
649 // Figure out how to advance the combined relocation point
650 // first to the beginning of this section.
651 // We'll insert one or more filler relocs to span that gap.
652 // (Don't bother to improve this by editing the first reloc's offset.)
653 csize_t new_code_point = code_end_so_far;
654 for (csize_t jump;
655 code_point_so_far < new_code_point;
656 code_point_so_far += jump) {
657 jump = new_code_point - code_point_so_far;
658 relocInfo filler = relocInfo::filler_info();
659 if (jump >= filler.addr_offset()) {
660 jump = filler.addr_offset();
661 } else { // else shrink the filler to fit
662 filler = relocInfo(relocInfo::none, jump);
663 }
664 if (buf != nullptr) {
665 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
666 *(relocInfo*)(buf+buf_offset) = filler;
667 }
668 buf_offset += sizeof(filler);
669 }
670
671 // Update code point and end to skip past this section:
672 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
673 assert(code_point_so_far <= last_code_point, "sanity");
674 code_point_so_far = last_code_point; // advance past this guy's relocs
675 }
676 code_end_so_far += csize; // advance past this guy's instructions too
677
678 // Done with filler; emit the real relocations:
679 if (buf != nullptr && lsize != 0) {
680 assert(buf_offset + lsize <= buf_limit, "target in bounds");
681 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
682 if (buf_offset % HeapWordSize == 0) {
683 // Use wordwise copies if possible:
684 Copy::disjoint_words((HeapWord*)lstart,
685 (HeapWord*)(buf+buf_offset),
686 (lsize + HeapWordSize-1) / HeapWordSize);
687 } else {
688 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
689 }
690 }
691 buf_offset += lsize;
692 }
693
694 // Align end of relocation info in target.
695 while (buf_offset % HeapWordSize != 0) {
696 if (buf != nullptr) {
697 relocInfo padding = relocInfo(relocInfo::none, 0);
698 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
699 *(relocInfo*)(buf+buf_offset) = padding;
700 }
701 buf_offset += sizeof(relocInfo);
702 }
703
704 assert(code_end_so_far == total_content_size(), "sanity");
705
706 return buf_offset;
707 }
708
709 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
710 address buf = nullptr;
711 csize_t buf_offset = 0;
712 csize_t buf_limit = 0;
713
714 if (dest != nullptr) {
715 buf = (address)dest->relocation_begin();
716 buf_limit = (address)dest->relocation_end() - buf;
717 }
718 // if dest is null, this is just the sizing pass
719 //
720 buf_offset = copy_relocations_to(buf, buf_limit);
721
722 return buf_offset;
723 }
724
725 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
726 #ifndef PRODUCT
727 if (PrintNMethods && (WizardMode || Verbose)) {
728 tty->print("done with CodeBuffer:");
729 ((CodeBuffer*)this)->print_on(tty);
730 }
731 #endif //PRODUCT
732
733 CodeBuffer dest(dest_blob);
734 assert(dest_blob->content_size() >= total_content_size(), "good sizing");
735 this->compute_final_layout(&dest);
736
737 // Set beginning of constant table before relocating.
738 dest_blob->set_ctable_begin(dest.consts()->start());
739
740 relocate_code_to(&dest);
741
742 // Share assembly remarks and debug strings with the blob.
743 NOT_PRODUCT(dest_blob->use_remarks(_asm_remarks));
744 NOT_PRODUCT(dest_blob->use_strings(_dbg_strings));
745
746 // Done moving code bytes; were they the right size?
747 assert((int)align_up(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity");
748 }
749
750 // Move all my code into another code buffer. Consult applicable
751 // relocs to repair embedded addresses. The layout in the destination
752 // CodeBuffer is different to the source CodeBuffer: the destination
753 // CodeBuffer gets the final layout (consts, insts, stubs in order of
754 // ascending address).
755 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
756 address dest_end = dest->_total_start + dest->_total_size;
757 address dest_filled = nullptr;
758 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
759 // pull code out of each section
760 const CodeSection* cs = code_section(n);
761 if (cs->is_empty()) continue; // skip trivial section
762 CodeSection* dest_cs = dest->code_section(n);
763 assert(cs->size() == dest_cs->size(), "sanity");
764 csize_t usize = dest_cs->size();
765 csize_t wsize = align_up(usize, HeapWordSize);
766 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
767 // Copy the code as aligned machine words.
768 // This may also include an uninitialized partial word at the end.
769 Copy::disjoint_words((HeapWord*)cs->start(),
770 (HeapWord*)dest_cs->start(),
771 wsize / HeapWordSize);
772
773 if (dest->blob() == nullptr) {
774 // Destination is a final resting place, not just another buffer.
775 // Normalize uninitialized bytes in the final padding.
776 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
777 Assembler::code_fill_byte());
778 }
779 // Keep track of the highest filled address
780 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining());
781
782 assert(cs->locs_start() != (relocInfo*)badAddress,
783 "this section carries no reloc storage, but reloc was attempted");
784
785 // Make the new code copy use the old copy's relocations:
786 dest_cs->initialize_locs_from(cs);
787 }
788
789 // Do relocation after all sections are copied.
790 // This is necessary if the code uses constants in stubs, which are
791 // relocated when the corresponding instruction in the code (e.g., a
792 // call) is relocated. Stubs are placed behind the main code
793 // section, so that section has to be copied before relocating.
794 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
795 CodeSection* dest_cs = dest->code_section(n);
796 if (dest_cs->is_empty() || (dest_cs->locs_count() == 0)) continue; // skip trivial section
797 { // Repair the pc relative information in the code after the move
798 RelocIterator iter(dest_cs);
799 while (iter.next()) {
800 iter.reloc()->fix_relocation_after_move(this, dest);
801 }
802 }
803 }
804
805 if (dest->blob() == nullptr && dest_filled != nullptr) {
806 // Destination is a final resting place, not just another buffer.
807 // Normalize uninitialized bytes in the final padding.
808 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,
809 Assembler::code_fill_byte());
810
811 }
812 }
813
814 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
815 csize_t amount,
816 csize_t* new_capacity) {
817 csize_t new_total_cap = 0;
818
819 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
820 const CodeSection* sect = code_section(n);
821
822 if (!sect->is_empty()) {
823 // Compute initial padding; assign it to the previous section,
824 // even if it's empty (e.g. consts section can be empty).
825 // Cf. compute_final_layout
826 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
827 if (padding != 0) {
828 new_total_cap += padding;
829 assert(n - 1 >= SECT_FIRST, "sanity");
830 new_capacity[n - 1] += padding;
831 }
832 }
833
834 csize_t exp = sect->size(); // 100% increase
835 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
836 if (sect == which_cs) {
837 if (exp < amount) exp = amount;
838 if (StressCodeBuffers) exp = amount; // expand only slightly
839 } else if (n == SECT_INSTS) {
840 // scale down inst increases to a more modest 25%
841 exp = 4*K + ((exp - 4*K) >> 2);
842 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
843 } else if (sect->is_empty()) {
844 // do not grow an empty secondary section
845 exp = 0;
846 }
847 // Allow for inter-section slop:
848 exp += CodeSection::end_slop();
849 csize_t new_cap = sect->size() + exp;
850 if (new_cap < sect->capacity()) {
851 // No need to expand after all.
852 new_cap = sect->capacity();
853 }
854 new_capacity[n] = new_cap;
855 new_total_cap += new_cap;
856 }
857
858 return new_total_cap;
859 }
860
861 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
862 #ifdef ASSERT
863 // The code below copies contents across temp buffers. The following
864 // sizes relate to buffer contents, and should not be changed by buffer
865 // expansion.
866 int old_total_skipped = total_skipped_instructions_size();
867 #endif
868
869 #ifndef PRODUCT
870 if (PrintNMethods && (WizardMode || Verbose)) {
871 tty->print("expanding CodeBuffer:");
872 this->print_on(tty);
873 }
874
875 if (StressCodeBuffers && blob() != nullptr) {
876 static int expand_count = 0;
877 if (expand_count >= 0) expand_count += 1;
878 if (expand_count > 100 && is_power_of_2(expand_count)) {
879 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
880 // simulate an occasional allocation failure:
881 free_blob();
882 }
883 }
884 #endif //PRODUCT
885
886 // Resizing must be allowed
887 {
888 if (blob() == nullptr) return; // caller must check if blob is null
889 }
890
891 // Figure new capacity for each section.
892 csize_t new_capacity[SECT_LIMIT];
893 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT);
894 csize_t new_total_cap
895 = figure_expanded_capacities(which_cs, amount, new_capacity);
896
897 // Create a new (temporary) code buffer to hold all the new data
898 CodeBuffer cb(name(), new_total_cap, 0);
899 cb.set_const_section_alignment(_const_section_alignment);
900 if (cb.blob() == nullptr) {
901 // Failed to allocate in code cache.
902 free_blob();
903 return;
904 }
905
906 // Create an old code buffer to remember which addresses used to go where.
907 // This will be useful when we do final assembly into the code cache,
908 // because we will need to know how to warp any internal address that
909 // has been created at any time in this CodeBuffer's past.
910 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
911 bxp->take_over_code_from(this); // remember the old undersized blob
912 DEBUG_ONLY(this->_blob = nullptr); // silence a later assert
913 bxp->_before_expand = this->_before_expand;
914 this->_before_expand = bxp;
915
916 // Give each section its required (expanded) capacity.
917 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) {
918 CodeSection* cb_sect = cb.code_section(n);
919 CodeSection* this_sect = code_section(n);
920 if (new_capacity[n] == 0) continue; // already nulled out
921 if (n != SECT_INSTS) {
922 cb.initialize_section_size(cb_sect, new_capacity[n]);
923 }
924 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
925 address cb_start = cb_sect->start();
926 cb_sect->set_end(cb_start + this_sect->size());
927 cb_sect->register_skipped(this_sect->_skipped_instructions_size);
928 if (this_sect->mark() == nullptr) {
929 cb_sect->clear_mark();
930 } else {
931 cb_sect->set_mark(cb_start + this_sect->mark_off());
932 }
933 }
934
935 // Needs to be initialized when calling fix_relocation_after_move.
936 cb.blob()->set_ctable_begin(cb.consts()->start());
937
938 // Move all the code and relocations to the new blob:
939 relocate_code_to(&cb);
940
941 // some internal addresses, _last_merge_candidate and _last_label, are used during
942 // code emission, adjust them in expansion
943 adjust_internal_address(insts_begin(), cb.insts_begin());
944
945 // Copy the temporary code buffer into the current code buffer.
946 // Basically, do {*this = cb}, except for some control information.
947 this->take_over_code_from(&cb);
948 cb.set_blob(nullptr);
949
950 // Zap the old code buffer contents, to avoid mistakenly using them.
951 DEBUG_ONLY(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
952 badCodeHeapFreeVal);)
953
954 // Make certain that the new sections are all snugly inside the new blob.
955 DEBUG_ONLY(verify_section_allocation();)
956
957 #ifndef PRODUCT
958 _decode_begin = nullptr; // sanity
959 if (PrintNMethods && (WizardMode || Verbose)) {
960 tty->print("expanded CodeBuffer:");
961 this->print_on(tty);
962 }
963 #endif //PRODUCT
964
965 assert(old_total_skipped == total_skipped_instructions_size(),
966 "Should match: %d == %d", old_total_skipped, total_skipped_instructions_size());
967 }
968
969 void CodeBuffer::adjust_internal_address(address from, address to) {
970 if (_last_merge_candidate != nullptr) {
971 _last_merge_candidate += to - from;
972 }
973 if (_last_label != nullptr) {
974 _last_label += to - from;
975 }
976 }
977
978 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
979 // Must already have disposed of the old blob somehow.
980 assert(blob() == nullptr, "must be empty");
981 // Take the new blob away from cb.
982 set_blob(cb->blob());
983 // Take over all the section pointers.
984 for (int n = 0; n < (int)SECT_LIMIT; n++) {
985 CodeSection* cb_sect = cb->code_section(n);
986 CodeSection* this_sect = code_section(n);
987 this_sect->take_over_code_from(cb_sect);
988 }
989 // Make sure the old cb won't try to use it or free it.
990 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
991 }
992
993 void CodeBuffer::verify_section_allocation() {
994 address tstart = _total_start;
995 if (tstart == nullptr) return; // ignore not fully initialized buffer
996 if (tstart == badAddress) return; // smashed by set_blob(nullptr)
997 address tend = tstart + _total_size;
998 if (_blob != nullptr) {
999 guarantee(tstart >= _blob->content_begin(), "sanity");
1000 guarantee(tend <= _blob->content_end(), "sanity");
1001 }
1002 // Verify disjointness.
1003 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
1004 CodeSection* sect = code_section(n);
1005 if (!sect->is_allocated() || sect->is_empty()) {
1006 continue;
1007 }
1008 guarantee(_blob == nullptr || is_aligned(sect->start(), sect->alignment()),
1009 "start is aligned");
1010 for (int m = n + 1; m < (int) SECT_LIMIT; m++) {
1011 CodeSection* other = code_section(m);
1012 if (!other->is_allocated() || other == sect) {
1013 continue;
1014 }
1015 guarantee(other->disjoint(sect), "sanity");
1016 }
1017 guarantee(sect->end() <= tend, "sanity");
1018 guarantee(sect->end() <= sect->limit(), "sanity");
1019 }
1020 }
1021
1022 void CodeBuffer::log_section_sizes(const char* name) {
1023 if (xtty != nullptr) {
1024 ttyLocker ttyl;
1025 // log info about buffer usage
1026 xtty->print_cr("<blob name='%s' total_size='%d'>", name, _total_size);
1027 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
1028 CodeSection* sect = code_section(n);
1029 if (!sect->is_allocated() || sect->is_empty()) continue;
1030 xtty->print_cr("<sect index='%d' capacity='%d' size='%d' remaining='%d'/>",
1031 n, sect->capacity(), sect->size(), sect->remaining());
1032 }
1033 xtty->print_cr("</blob>");
1034 }
1035 }
1036
1037 bool CodeBuffer::finalize_stubs() {
1038 if (_finalize_stubs && !pd_finalize_stubs()) {
1039 // stub allocation failure
1040 return false;
1041 }
1042 _finalize_stubs = false;
1043 return true;
1044 }
1045
1046 void CodeBuffer::shared_stub_to_interp_for(ciMethod* callee, csize_t call_offset) {
1047 if (_shared_stub_to_interp_requests == nullptr) {
1048 _shared_stub_to_interp_requests = new SharedStubToInterpRequests(8);
1049 }
1050 SharedStubToInterpRequest request(callee, call_offset);
1051 _shared_stub_to_interp_requests->push(request);
1052 _finalize_stubs = true;
1053 }
1054
1055 #ifndef PRODUCT
1056 void CodeBuffer::block_comment(ptrdiff_t offset, const char* comment) {
1057 if (insts()->scratch_emit()) {
1058 return;
1059 }
1060 if (_collect_comments) {
1061 const char* str = _asm_remarks.insert(offset, comment);
1062 postcond(str != comment);
1063 }
1064 }
1065
1066 const char* CodeBuffer::code_string(const char* str) {
1067 if (insts()->scratch_emit()) {
1068 return str;
1069 }
1070 const char* tmp = _dbg_strings.insert(str);
1071 postcond(tmp != str);
1072 return tmp;
1073 }
1074
1075 void CodeBuffer::decode() {
1076 ttyLocker ttyl;
1077 Disassembler::decode(decode_begin(), insts_end(), tty NOT_PRODUCT(COMMA &asm_remarks()));
1078 _decode_begin = insts_end();
1079 }
1080
1081 void CodeSection::print_on(outputStream* st, const char* name) {
1082 csize_t locs_size = locs_end() - locs_start();
1083 st->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)",
1084 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity());
1085 st->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1086 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off());
1087 if (PrintRelocations && (locs_size != 0)) {
1088 RelocIterator iter(this);
1089 iter.print_on(st);
1090 }
1091 }
1092
1093 void CodeBuffer::print_on(outputStream* st) {
1094 st->print_cr("CodeBuffer:%s", name());
1095 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1096 // print each section
1097 CodeSection* cs = code_section(n);
1098 cs->print_on(st, code_section_name(n));
1099 }
1100 }
1101
1102 CHeapString::~CHeapString() {
1103 os::free((void*)_string);
1104 _string = nullptr;
1105 }
1106
1107 // ----- AsmRemarks ------------------------------------------------------------
1108 //
1109 // Acting as interface to reference counted mapping [offset -> remark], where
1110 // offset is a byte offset into an instruction stream (CodeBuffer, CodeBlob or
1111 // other memory buffer) and remark is a string (comment).
1112 //
1113 AsmRemarks::AsmRemarks() {
1114 init();
1115 assert(_remarks != nullptr, "Allocation failure!");
1116 }
1117
1118 AsmRemarks::~AsmRemarks() {
1119 assert(_remarks == nullptr, "Must 'clear()' before deleting!");
1120 }
1121
1122 void AsmRemarks::init() {
1123 _remarks = new AsmRemarkCollection();
1124 }
1125
1126 const char* AsmRemarks::insert(uint offset, const char* remstr) {
1127 precond(remstr != nullptr);
1128 return _remarks->insert(offset, remstr);
1129 }
1130
1131 bool AsmRemarks::is_empty() const {
1132 return _remarks->is_empty();
1133 }
1134
1135 void AsmRemarks::share(const AsmRemarks &src) {
1136 precond(_remarks == nullptr || is_empty());
1137 clear();
1138 _remarks = src._remarks->reuse();
1139 }
1140
1141 void AsmRemarks::clear() {
1142 if (_remarks != nullptr && _remarks->clear() == 0) {
1143 delete _remarks;
1144 }
1145 _remarks = nullptr;
1146 }
1147
1148 uint AsmRemarks::print(uint offset, outputStream* strm) const {
1149 uint count = 0;
1150 const char* prefix = " ;; ";
1151 const char* remstr = (_remarks ? _remarks->lookup(offset) : nullptr);
1152 while (remstr != nullptr) {
1153 strm->bol();
1154 strm->print("%s", prefix);
1155 // Don't interpret as format strings since it could contain '%'.
1156 strm->print_raw(remstr);
1157 // Advance to next line iff string didn't contain a cr() at the end.
1158 strm->bol();
1159 remstr = _remarks->next(offset);
1160 count++;
1161 }
1162 return count;
1163 }
1164
1165 // ----- DbgStrings ------------------------------------------------------------
1166 //
1167 // Acting as interface to reference counted collection of (debug) strings used
1168 // in the code generated, and thus requiring a fixed address.
1169 //
1170 DbgStrings::DbgStrings() {
1171 init();
1172 assert(_strings != nullptr, "Allocation failure!");
1173 }
1174
1175 DbgStrings::~DbgStrings() {
1176 assert(_strings == nullptr, "Must 'clear()' before deleting!");
1177 }
1178
1179 void DbgStrings::init() {
1180 _strings = new DbgStringCollection();
1181 }
1182
1183 const char* DbgStrings::insert(const char* dbgstr) {
1184 const char* str = _strings->lookup(dbgstr);
1185 return str != nullptr ? str : _strings->insert(dbgstr);
1186 }
1187
1188 bool DbgStrings::is_empty() const {
1189 return _strings->is_empty();
1190 }
1191
1192 void DbgStrings::share(const DbgStrings &src) {
1193 precond(_strings == nullptr || is_empty());
1194 clear();
1195 _strings = src._strings->reuse();
1196 }
1197
1198 void DbgStrings::clear() {
1199 if (_strings != nullptr && _strings->clear() == 0) {
1200 delete _strings;
1201 }
1202 _strings = nullptr;
1203 }
1204
1205 // ----- AsmRemarkCollection ---------------------------------------------------
1206
1207 const char* AsmRemarkCollection::insert(uint offset, const char* remstr) {
1208 precond(remstr != nullptr);
1209 Cell* cell = new Cell { remstr, offset };
1210 if (is_empty()) {
1211 cell->prev = cell;
1212 cell->next = cell;
1213 _remarks = cell;
1214 } else {
1215 _remarks->push_back(cell);
1216 }
1217 return cell->string();
1218 }
1219
1220 const char* AsmRemarkCollection::lookup(uint offset) const {
1221 _next = _remarks;
1222 return next(offset);
1223 }
1224
1225 const char* AsmRemarkCollection::next(uint offset) const {
1226 if (_next != nullptr) {
1227 Cell* i = _next;
1228 do {
1229 if (i->offset == offset) {
1230 _next = i->next == _remarks ? nullptr : i->next;
1231 return i->string();
1232 }
1233 i = i->next;
1234 } while (i != _remarks);
1235 _next = nullptr;
1236 }
1237 return nullptr;
1238 }
1239
1240 uint AsmRemarkCollection::clear() {
1241 precond(_ref_cnt > 0);
1242 if (--_ref_cnt > 0) {
1243 return _ref_cnt;
1244 }
1245 if (!is_empty()) {
1246 uint count = 0;
1247 Cell* i = _remarks;
1248 do {
1249 Cell* next = i->next;
1250 delete i;
1251 i = next;
1252 count++;
1253 } while (i != _remarks);
1254
1255 log_debug(codestrings)("Clear %u asm-remark%s.", count, count == 1 ? "" : "s");
1256 _remarks = nullptr;
1257 }
1258 return 0; // i.e. _ref_cnt == 0
1259 }
1260
1261 // ----- DbgStringCollection ---------------------------------------------------
1262
1263 const char* DbgStringCollection::insert(const char* dbgstr) {
1264 precond(dbgstr != nullptr);
1265 Cell* cell = new Cell { dbgstr };
1266
1267 if (is_empty()) {
1268 cell->prev = cell;
1269 cell->next = cell;
1270 _strings = cell;
1271 } else {
1272 _strings->push_back(cell);
1273 }
1274 return cell->string();
1275 }
1276
1277 const char* DbgStringCollection::lookup(const char* dbgstr) const {
1278 precond(dbgstr != nullptr);
1279 if (_strings != nullptr) {
1280 Cell* i = _strings;
1281 do {
1282 if (strcmp(i->string(), dbgstr) == 0) {
1283 return i->string();
1284 }
1285 i = i->next;
1286 } while (i != _strings);
1287 }
1288 return nullptr;
1289 }
1290
1291 uint DbgStringCollection::clear() {
1292 precond(_ref_cnt > 0);
1293 if (--_ref_cnt > 0) {
1294 return _ref_cnt;
1295 }
1296 if (!is_empty()) {
1297 uint count = 0;
1298 Cell* i = _strings;
1299 do {
1300 Cell* next = i->next;
1301 delete i;
1302 i = next;
1303 count++;
1304 } while (i != _strings);
1305
1306 log_debug(codestrings)("Clear %u dbg-string%s.", count, count == 1 ? "" : "s");
1307 _strings = nullptr;
1308 }
1309 return 0; // i.e. _ref_cnt == 0
1310 }
1311
1312 #endif // not PRODUCT