1 /*
2 * Copyright (c) 1997, 2023, 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 "asm/codeBuffer.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/methodData.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "runtime/icache.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(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 // Always allow for empty slop around each section.
101 int slop = (int) CodeSection::end_slop();
102
103 assert(SECT_LIMIT == 3, "total_size explicitly lists all section alignments");
104 int total_size = code_size + _consts.alignment() + _insts.alignment() + _stubs.alignment() + SECT_LIMIT * slop;
105
106 assert(blob() == nullptr, "only once");
107 set_blob(BufferBlob::create(_name, total_size));
108 if (blob() == nullptr) {
109 // The assembler constructor will throw a fatal on an empty CodeBuffer.
110 return; // caller must test this
111 }
112
113 // Set up various pointers into the blob.
114 initialize(_total_start, _total_size);
115
116 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
117
118 pd_initialize();
119
120 if (locs_size != 0) {
121 _insts.initialize_locs(locs_size / sizeof(relocInfo));
122 }
123
124 debug_only(verify_section_allocation();)
125 }
126
127
128 CodeBuffer::~CodeBuffer() {
129 verify_section_allocation();
130
131 // If we allocated our code buffer from the CodeCache via a BufferBlob, and
132 // it's not permanent, then free the BufferBlob. The rest of the memory
133 // will be freed when the ResourceObj is released.
134 for (CodeBuffer* cb = this; cb != nullptr; cb = cb->before_expand()) {
135 // Previous incarnations of this buffer are held live, so that internal
136 // addresses constructed before expansions will not be confused.
137 cb->free_blob();
138 // free any overflow storage
139 delete cb->_overflow_arena;
140 }
141
142 if (_shared_trampoline_requests != nullptr) {
143 delete _shared_trampoline_requests;
144 }
145
146 NOT_PRODUCT(clear_strings());
147 }
148
149 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
150 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
151 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen
152 _oop_recorder = r;
153 }
154
155 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
156 assert(cs != &_insts, "insts is the memory provider, not the consumer");
157 csize_t slop = CodeSection::end_slop(); // margin between sections
158 int align = cs->alignment();
159 assert(is_power_of_2(align), "sanity");
160 address start = _insts._start;
161 address limit = _insts._limit;
162 address middle = limit - size;
163 middle -= (intptr_t)middle & (align-1); // align the division point downward
164 guarantee(middle - slop > start, "need enough space to divide up");
165 _insts._limit = middle - slop; // subtract desired space, plus slop
166 cs->initialize(middle, limit - middle);
167 assert(cs->start() == middle, "sanity");
168 assert(cs->limit() == limit, "sanity");
169 // give it some relocations to start with, if the main section has them
170 if (_insts.has_locs()) cs->initialize_locs(1);
171 }
172
173 void CodeBuffer::set_blob(BufferBlob* blob) {
174 _blob = blob;
175 if (blob != nullptr) {
176 address start = blob->content_begin();
177 address end = blob->content_end();
178 // Round up the starting address.
179 int align = _insts.alignment();
180 start += (-(intptr_t)start) & (align-1);
181 _total_start = start;
182 _total_size = end - start;
183 } else {
184 #ifdef ASSERT
185 // Clean out dangling pointers.
186 _total_start = badAddress;
187 _consts._start = _consts._end = badAddress;
188 _insts._start = _insts._end = badAddress;
189 _stubs._start = _stubs._end = badAddress;
190 #endif //ASSERT
191 }
192 }
193
194 void CodeBuffer::free_blob() {
195 if (_blob != nullptr) {
196 BufferBlob::free(_blob);
197 set_blob(nullptr);
198 }
199 }
200
201 const char* CodeBuffer::code_section_name(int n) {
202 #ifdef PRODUCT
203 return nullptr;
204 #else //PRODUCT
205 switch (n) {
206 case SECT_CONSTS: return "consts";
207 case SECT_INSTS: return "insts";
208 case SECT_STUBS: return "stubs";
209 default: return nullptr;
210 }
211 #endif //PRODUCT
212 }
213
214 int CodeBuffer::section_index_of(address addr) const {
215 for (int n = 0; n < (int)SECT_LIMIT; n++) {
216 const CodeSection* cs = code_section(n);
217 if (cs->allocates(addr)) return n;
218 }
219 return SECT_NONE;
220 }
221
222 int CodeBuffer::locator(address addr) const {
223 for (int n = 0; n < (int)SECT_LIMIT; n++) {
224 const CodeSection* cs = code_section(n);
225 if (cs->allocates(addr)) {
226 return locator(addr - cs->start(), n);
227 }
228 }
229 return -1;
230 }
231
232
233 bool CodeBuffer::is_backward_branch(Label& L) {
234 return L.is_bound() && insts_end() <= locator_address(L.loc());
235 }
236
237 #ifndef PRODUCT
238 address CodeBuffer::decode_begin() {
239 address begin = _insts.start();
240 if (_decode_begin != nullptr && _decode_begin > begin)
241 begin = _decode_begin;
242 return begin;
243 }
244 #endif // !PRODUCT
245
246 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
247 if (_overflow_arena == nullptr) {
248 _overflow_arena = new (mtCode) Arena(mtCode);
249 }
250 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
251 }
252
253
254 // Helper function for managing labels and their target addresses.
255 // Returns a sensible address, and if it is not the label's final
256 // address, notes the dependency (at 'branch_pc') on the label.
257 address CodeSection::target(Label& L, address branch_pc) {
258 if (L.is_bound()) {
259 int loc = L.loc();
260 if (index() == CodeBuffer::locator_sect(loc)) {
261 return start() + CodeBuffer::locator_pos(loc);
262 } else {
263 return outer()->locator_address(loc);
264 }
265 } else {
266 assert(allocates2(branch_pc), "sanity");
267 address base = start();
268 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
269 L.add_patch_at(outer(), patch_loc);
270
271 // Need to return a pc, doesn't matter what it is since it will be
272 // replaced during resolution later.
273 // Don't return null or badAddress, since branches shouldn't overflow.
274 // Don't return base either because that could overflow displacements
275 // for shorter branches. It will get checked when bound.
276 return branch_pc;
277 }
278 }
279
280 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) {
281 RelocationHolder rh;
282 switch (rtype) {
283 case relocInfo::none: return;
284 case relocInfo::opt_virtual_call_type: {
285 rh = opt_virtual_call_Relocation::spec(method_index);
286 break;
287 }
288 case relocInfo::static_call_type: {
289 rh = static_call_Relocation::spec(method_index);
290 break;
291 }
292 case relocInfo::virtual_call_type: {
293 assert(method_index == 0, "resolved method overriding is not supported");
294 rh = Relocation::spec_simple(rtype);
295 break;
296 }
297 default: {
298 rh = Relocation::spec_simple(rtype);
299 break;
300 }
301 }
302 relocate(at, rh, format);
303 }
304
305 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
306 // Do not relocate in scratch buffers.
307 if (scratch_emit()) { return; }
308 Relocation* reloc = spec.reloc();
309 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
310 if (rtype == relocInfo::none) return;
311
312 // The assertion below has been adjusted, to also work for
313 // relocation for fixup. Sometimes we want to put relocation
314 // information for the next instruction, since it will be patched
315 // with a call.
316 assert(start() <= at && at <= end()+1,
317 "cannot relocate data outside code boundaries");
318
319 if (!has_locs()) {
320 // no space for relocation information provided => code cannot be
321 // relocated. Make sure that relocate is only called with rtypes
322 // that can be ignored for this kind of code.
323 assert(rtype == relocInfo::none ||
324 rtype == relocInfo::runtime_call_type ||
325 rtype == relocInfo::internal_word_type||
326 rtype == relocInfo::section_word_type ||
327 rtype == relocInfo::external_word_type||
328 rtype == relocInfo::barrier_type,
329 "code needs relocation information");
330 // leave behind an indication that we attempted a relocation
331 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
332 return;
333 }
334
335 // Advance the point, noting the offset we'll have to record.
336 csize_t offset = at - locs_point();
337 set_locs_point(at);
338
339 // Test for a couple of overflow conditions; maybe expand the buffer.
340 relocInfo* end = locs_end();
341 relocInfo* req = end + relocInfo::length_limit;
342 // Check for (potential) overflow
343 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
344 req += (uint)offset / (uint)relocInfo::offset_limit();
345 if (req >= locs_limit()) {
346 // Allocate or reallocate.
347 expand_locs(locs_count() + (req - end));
348 // reload pointer
349 end = locs_end();
350 }
351 }
352
353 // If the offset is giant, emit filler relocs, of type 'none', but
354 // each carrying the largest possible offset, to advance the locs_point.
355 while (offset >= relocInfo::offset_limit()) {
356 assert(end < locs_limit(), "adjust previous paragraph of code");
357 *end++ = relocInfo::filler_info();
358 offset -= relocInfo::filler_info().addr_offset();
359 }
360
361 // If it's a simple reloc with no data, we'll just write (rtype | offset).
362 (*end) = relocInfo(rtype, offset, format);
363
364 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
365 end->initialize(this, reloc);
366 }
367
368 void CodeSection::initialize_locs(int locs_capacity) {
369 assert(_locs_start == nullptr, "only one locs init step, please");
370 // Apply a priori lower limits to relocation size:
371 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
372 if (locs_capacity < min_locs) locs_capacity = min_locs;
373 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
374 _locs_start = locs_start;
375 _locs_end = locs_start;
376 _locs_limit = locs_start + locs_capacity;
377 _locs_own = true;
378 }
379
380 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
381 assert(_locs_start == nullptr, "do this before locs are allocated");
382 // Internal invariant: locs buf must be fully aligned.
383 // See copy_relocations_to() below.
384 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
385 ++buf; --length;
386 }
387 if (length > 0) {
388 _locs_start = buf;
389 _locs_end = buf;
390 _locs_limit = buf + length;
391 _locs_own = false;
392 }
393 }
394
395 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
396 int lcount = source_cs->locs_count();
397 if (lcount != 0) {
398 initialize_shared_locs(source_cs->locs_start(), lcount);
399 _locs_end = _locs_limit = _locs_start + lcount;
400 assert(is_allocated(), "must have copied code already");
401 set_locs_point(start() + source_cs->locs_point_off());
402 }
403 assert(this->locs_count() == source_cs->locs_count(), "sanity");
404 }
405
406 void CodeSection::expand_locs(int new_capacity) {
407 if (_locs_start == nullptr) {
408 initialize_locs(new_capacity);
409 return;
410 } else {
411 int old_count = locs_count();
412 int old_capacity = locs_capacity();
413 if (new_capacity < old_capacity * 2)
414 new_capacity = old_capacity * 2;
415 relocInfo* locs_start;
416 if (_locs_own) {
417 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
418 } else {
419 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
420 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
421 _locs_own = true;
422 }
423 _locs_start = locs_start;
424 _locs_end = locs_start + old_count;
425 _locs_limit = locs_start + new_capacity;
426 }
427 }
428
429 int CodeSection::alignment() const {
430 if (_index == CodeBuffer::SECT_CONSTS) {
431 // CodeBuffer controls the alignment of the constants section
432 return _outer->_const_section_alignment;
433 }
434 if (_index == CodeBuffer::SECT_INSTS) {
435 return (int) CodeEntryAlignment;
436 }
437 if (_index == CodeBuffer::SECT_STUBS) {
438 // CodeBuffer installer expects sections to be HeapWordSize aligned
439 return HeapWordSize;
440 }
441 ShouldNotReachHere();
442 return 0;
443 }
444
445 /// Support for emitting the code to its final location.
446 /// The pattern is the same for all functions.
447 /// We iterate over all the sections, padding each to alignment.
448
449 csize_t CodeBuffer::total_content_size() const {
450 csize_t size_so_far = 0;
451 for (int n = 0; n < (int)SECT_LIMIT; n++) {
452 const CodeSection* cs = code_section(n);
453 if (cs->is_empty()) continue; // skip trivial section
454 size_so_far = cs->align_at_start(size_so_far);
455 size_so_far += cs->size();
456 }
457 return size_so_far;
458 }
459
460 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
461 address buf = dest->_total_start;
462 csize_t buf_offset = 0;
463 assert(dest->_total_size >= total_content_size(), "must be big enough");
464 assert(!_finalize_stubs, "non-finalized stubs");
465
466 {
467 // not sure why this is here, but why not...
468 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
469 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
470 }
471
472 const CodeSection* prev_cs = nullptr;
473 CodeSection* prev_dest_cs = nullptr;
474
475 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
476 // figure compact layout of each section
477 const CodeSection* cs = code_section(n);
478 csize_t csize = cs->size();
479
480 CodeSection* dest_cs = dest->code_section(n);
481 if (!cs->is_empty()) {
482 // Compute initial padding; assign it to the previous non-empty guy.
483 // Cf. figure_expanded_capacities.
484 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
485 if (prev_dest_cs != nullptr) {
486 if (padding != 0) {
487 buf_offset += padding;
488 prev_dest_cs->_limit += padding;
489 }
490 } else {
491 guarantee(padding == 0, "In first iteration no padding should be needed.");
492 }
493 prev_dest_cs = dest_cs;
494 prev_cs = cs;
495 }
496
497 debug_only(dest_cs->_start = nullptr); // defeat double-initialization assert
498 dest_cs->initialize(buf+buf_offset, csize);
499 dest_cs->set_end(buf+buf_offset+csize);
500 assert(dest_cs->is_allocated(), "must always be allocated");
501 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
502
503 buf_offset += csize;
504 }
505
506 // Done calculating sections; did it come out to the right end?
507 assert(buf_offset == total_content_size(), "sanity");
508 debug_only(dest->verify_section_allocation();)
509 }
510
511 // Append an oop reference that keeps the class alive.
512 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) {
513 oop cl = k->klass_holder();
514 if (cl != nullptr && !oops->contains(cl)) {
515 oops->append(cl);
516 }
517 }
518
519 void CodeBuffer::finalize_oop_references(const methodHandle& mh) {
520 NoSafepointVerifier nsv;
521
522 GrowableArray<oop> oops;
523
524 // Make sure that immediate metadata records something in the OopRecorder
525 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
526 // pull code out of each section
527 CodeSection* cs = code_section(n);
528 if (cs->is_empty() || !cs->has_locs()) continue; // skip trivial section
529 RelocIterator iter(cs);
530 while (iter.next()) {
531 if (iter.type() == relocInfo::metadata_type) {
532 metadata_Relocation* md = iter.metadata_reloc();
533 if (md->metadata_is_immediate()) {
534 Metadata* m = md->metadata_value();
535 if (oop_recorder()->is_real(m)) {
536 if (m->is_methodData()) {
537 m = ((MethodData*)m)->method();
538 }
539 if (m->is_method()) {
540 m = ((Method*)m)->method_holder();
541 }
542 if (m->is_klass()) {
543 append_oop_references(&oops, (Klass*)m);
544 } else {
545 // XXX This will currently occur for MDO which don't
546 // have a backpointer. This has to be fixed later.
547 m->print();
548 ShouldNotReachHere();
549 }
550 }
551 }
552 }
553 }
554 }
555
556 if (!oop_recorder()->is_unused()) {
557 for (int i = 0; i < oop_recorder()->metadata_count(); i++) {
558 Metadata* m = oop_recorder()->metadata_at(i);
559 if (oop_recorder()->is_real(m)) {
560 if (m->is_methodData()) {
561 m = ((MethodData*)m)->method();
562 }
563 if (m->is_method()) {
564 m = ((Method*)m)->method_holder();
565 }
566 if (m->is_klass()) {
567 append_oop_references(&oops, (Klass*)m);
568 } else {
569 m->print();
570 ShouldNotReachHere();
571 }
572 }
573 }
574
575 }
576
577 // Add the class loader of Method* for the nmethod itself
578 append_oop_references(&oops, mh->method_holder());
579
580 // Add any oops that we've found
581 Thread* thread = Thread::current();
582 for (int i = 0; i < oops.length(); i++) {
583 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i)));
584 }
585 }
586
587
588
589 csize_t CodeBuffer::total_offset_of(const CodeSection* cs) const {
590 csize_t size_so_far = 0;
591 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
592 const CodeSection* cur_cs = code_section(n);
593 if (!cur_cs->is_empty()) {
594 size_so_far = cur_cs->align_at_start(size_so_far);
595 }
596 if (cur_cs->index() == cs->index()) {
597 return size_so_far;
598 }
599 size_so_far += cur_cs->size();
600 }
601 ShouldNotReachHere();
602 return -1;
603 }
604
605 int CodeBuffer::total_skipped_instructions_size() const {
606 int total_skipped_size = 0;
607 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
608 const CodeSection* cur_cs = code_section(n);
609 if (!cur_cs->is_empty()) {
610 total_skipped_size += cur_cs->_skipped_instructions_size;
611 }
612 }
613 return total_skipped_size;
614 }
615
616 csize_t CodeBuffer::total_relocation_size() const {
617 csize_t total = copy_relocations_to(nullptr); // dry run only
618 return (csize_t) align_up(total, HeapWordSize);
619 }
620
621 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const {
622 csize_t buf_offset = 0;
623 csize_t code_end_so_far = 0;
624 csize_t code_point_so_far = 0;
625
626 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
627 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
628
629 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
630 if (only_inst && (n != (int)SECT_INSTS)) {
631 // Need only relocation info for code.
632 continue;
633 }
634 // pull relocs out of each section
635 const CodeSection* cs = code_section(n);
636 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
637 if (cs->is_empty()) continue; // skip trivial section
638 relocInfo* lstart = cs->locs_start();
639 relocInfo* lend = cs->locs_end();
640 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
641 csize_t csize = cs->size();
642 code_end_so_far = cs->align_at_start(code_end_so_far);
643
644 if (lsize > 0) {
645 // Figure out how to advance the combined relocation point
646 // first to the beginning of this section.
647 // We'll insert one or more filler relocs to span that gap.
648 // (Don't bother to improve this by editing the first reloc's offset.)
649 csize_t new_code_point = code_end_so_far;
650 for (csize_t jump;
651 code_point_so_far < new_code_point;
652 code_point_so_far += jump) {
653 jump = new_code_point - code_point_so_far;
654 relocInfo filler = relocInfo::filler_info();
655 if (jump >= filler.addr_offset()) {
656 jump = filler.addr_offset();
657 } else { // else shrink the filler to fit
658 filler = relocInfo(relocInfo::none, jump);
659 }
660 if (buf != nullptr) {
661 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
662 *(relocInfo*)(buf+buf_offset) = filler;
663 }
664 buf_offset += sizeof(filler);
665 }
666
667 // Update code point and end to skip past this section:
668 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
669 assert(code_point_so_far <= last_code_point, "sanity");
670 code_point_so_far = last_code_point; // advance past this guy's relocs
671 }
672 code_end_so_far += csize; // advance past this guy's instructions too
673
674 // Done with filler; emit the real relocations:
675 if (buf != nullptr && lsize != 0) {
676 assert(buf_offset + lsize <= buf_limit, "target in bounds");
677 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
678 if (buf_offset % HeapWordSize == 0) {
679 // Use wordwise copies if possible:
680 Copy::disjoint_words((HeapWord*)lstart,
681 (HeapWord*)(buf+buf_offset),
682 (lsize + HeapWordSize-1) / HeapWordSize);
683 } else {
684 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
685 }
686 }
687 buf_offset += lsize;
688 }
689
690 // Align end of relocation info in target.
691 while (buf_offset % HeapWordSize != 0) {
692 if (buf != nullptr) {
693 relocInfo padding = relocInfo(relocInfo::none, 0);
694 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
695 *(relocInfo*)(buf+buf_offset) = padding;
696 }
697 buf_offset += sizeof(relocInfo);
698 }
699
700 assert(only_inst || code_end_so_far == total_content_size(), "sanity");
701
702 return buf_offset;
703 }
704
705 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
706 address buf = nullptr;
707 csize_t buf_offset = 0;
708 csize_t buf_limit = 0;
709
710 if (dest != nullptr) {
711 buf = (address)dest->relocation_begin();
712 buf_limit = (address)dest->relocation_end() - buf;
713 }
714 // if dest is null, this is just the sizing pass
715 //
716 buf_offset = copy_relocations_to(buf, buf_limit, false);
717
718 return buf_offset;
719 }
720
721 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
722 #ifndef PRODUCT
723 if (PrintNMethods && (WizardMode || Verbose)) {
724 tty->print("done with CodeBuffer:");
725 ((CodeBuffer*)this)->print();
726 }
727 #endif //PRODUCT
728
729 CodeBuffer dest(dest_blob);
730 assert(dest_blob->content_size() >= total_content_size(), "good sizing");
731 this->compute_final_layout(&dest);
732
733 // Set beginning of constant table before relocating.
734 dest_blob->set_ctable_begin(dest.consts()->start());
735
736 relocate_code_to(&dest);
737
738 // Share assembly remarks and debug strings with the blob.
739 NOT_PRODUCT(dest_blob->use_remarks(_asm_remarks));
740 NOT_PRODUCT(dest_blob->use_strings(_dbg_strings));
741
742 // Done moving code bytes; were they the right size?
743 assert((int)align_up(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity");
744
745 // Flush generated code
746 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size());
747 }
748
749 // Move all my code into another code buffer. Consult applicable
750 // relocs to repair embedded addresses. The layout in the destination
751 // CodeBuffer is different to the source CodeBuffer: the destination
752 // CodeBuffer gets the final layout (consts, insts, stubs in order of
753 // ascending address).
754 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
755 address dest_end = dest->_total_start + dest->_total_size;
756 address dest_filled = nullptr;
757 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
758 // pull code out of each section
759 const CodeSection* cs = code_section(n);
760 if (cs->is_empty()) continue; // skip trivial section
761 CodeSection* dest_cs = dest->code_section(n);
762 assert(cs->size() == dest_cs->size(), "sanity");
763 csize_t usize = dest_cs->size();
764 csize_t wsize = align_up(usize, HeapWordSize);
765 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
766 // Copy the code as aligned machine words.
767 // This may also include an uninitialized partial word at the end.
768 Copy::disjoint_words((HeapWord*)cs->start(),
769 (HeapWord*)dest_cs->start(),
770 wsize / HeapWordSize);
771
772 if (dest->blob() == nullptr) {
773 // Destination is a final resting place, not just another buffer.
774 // Normalize uninitialized bytes in the final padding.
775 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
776 Assembler::code_fill_byte());
777 }
778 // Keep track of the highest filled address
779 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining());
780
781 assert(cs->locs_start() != (relocInfo*)badAddress,
782 "this section carries no reloc storage, but reloc was attempted");
783
784 // Make the new code copy use the old copy's relocations:
785 dest_cs->initialize_locs_from(cs);
786 }
787
788 // Do relocation after all sections are copied.
789 // This is necessary if the code uses constants in stubs, which are
790 // relocated when the corresponding instruction in the code (e.g., a
791 // call) is relocated. Stubs are placed behind the main code
792 // section, so that section has to be copied before relocating.
793 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
794 // pull code out of each section
795 const CodeSection* cs = code_section(n);
796 if (cs->is_empty() || !cs->has_locs()) continue; // skip trivial section
797 CodeSection* dest_cs = dest->code_section(n);
798 { // Repair the pc relative information in the code after the move
799 RelocIterator iter(dest_cs);
800 while (iter.next()) {
801 iter.reloc()->fix_relocation_after_move(this, dest);
802 }
803 }
804 }
805
806 if (dest->blob() == nullptr && dest_filled != nullptr) {
807 // Destination is a final resting place, not just another buffer.
808 // Normalize uninitialized bytes in the final padding.
809 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,
810 Assembler::code_fill_byte());
811
812 }
813 }
814
815 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
816 csize_t amount,
817 csize_t* new_capacity) {
818 csize_t new_total_cap = 0;
819
820 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
821 const CodeSection* sect = code_section(n);
822
823 if (!sect->is_empty()) {
824 // Compute initial padding; assign it to the previous section,
825 // even if it's empty (e.g. consts section can be empty).
826 // Cf. compute_final_layout
827 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
828 if (padding != 0) {
829 new_total_cap += padding;
830 assert(n - 1 >= SECT_FIRST, "sanity");
831 new_capacity[n - 1] += padding;
832 }
833 }
834
835 csize_t exp = sect->size(); // 100% increase
836 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
837 if (sect == which_cs) {
838 if (exp < amount) exp = amount;
839 if (StressCodeBuffers) exp = amount; // expand only slightly
840 } else if (n == SECT_INSTS) {
841 // scale down inst increases to a more modest 25%
842 exp = 4*K + ((exp - 4*K) >> 2);
843 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
844 } else if (sect->is_empty()) {
845 // do not grow an empty secondary section
846 exp = 0;
847 }
848 // Allow for inter-section slop:
849 exp += CodeSection::end_slop();
850 csize_t new_cap = sect->size() + exp;
851 if (new_cap < sect->capacity()) {
852 // No need to expand after all.
853 new_cap = sect->capacity();
854 }
855 new_capacity[n] = new_cap;
856 new_total_cap += new_cap;
857 }
858
859 return new_total_cap;
860 }
861
862 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
863 #ifndef PRODUCT
864 if (PrintNMethods && (WizardMode || Verbose)) {
865 tty->print("expanding CodeBuffer:");
866 this->print();
867 }
868
869 if (StressCodeBuffers && blob() != nullptr) {
870 static int expand_count = 0;
871 if (expand_count >= 0) expand_count += 1;
872 if (expand_count > 100 && is_power_of_2(expand_count)) {
873 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
874 // simulate an occasional allocation failure:
875 free_blob();
876 }
877 }
878 #endif //PRODUCT
879
880 // Resizing must be allowed
881 {
882 if (blob() == nullptr) return; // caller must check if blob is null
883 }
884
885 // Figure new capacity for each section.
886 csize_t new_capacity[SECT_LIMIT];
887 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT);
888 csize_t new_total_cap
889 = figure_expanded_capacities(which_cs, amount, new_capacity);
890
891 // Create a new (temporary) code buffer to hold all the new data
892 CodeBuffer cb(name(), new_total_cap, 0);
893 if (cb.blob() == nullptr) {
894 // Failed to allocate in code cache.
895 free_blob();
896 return;
897 }
898
899 // Create an old code buffer to remember which addresses used to go where.
900 // This will be useful when we do final assembly into the code cache,
901 // because we will need to know how to warp any internal address that
902 // has been created at any time in this CodeBuffer's past.
903 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
904 bxp->take_over_code_from(this); // remember the old undersized blob
905 DEBUG_ONLY(this->_blob = nullptr); // silence a later assert
906 bxp->_before_expand = this->_before_expand;
907 this->_before_expand = bxp;
908
909 // Give each section its required (expanded) capacity.
910 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) {
911 CodeSection* cb_sect = cb.code_section(n);
912 CodeSection* this_sect = code_section(n);
913 if (new_capacity[n] == 0) continue; // already nulled out
914 if (n != SECT_INSTS) {
915 cb.initialize_section_size(cb_sect, new_capacity[n]);
916 }
917 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
918 address cb_start = cb_sect->start();
919 cb_sect->set_end(cb_start + this_sect->size());
920 if (this_sect->mark() == nullptr) {
921 cb_sect->clear_mark();
922 } else {
923 cb_sect->set_mark(cb_start + this_sect->mark_off());
924 }
925 }
926
927 // Needs to be initialized when calling fix_relocation_after_move.
928 cb.blob()->set_ctable_begin(cb.consts()->start());
929
930 // Move all the code and relocations to the new blob:
931 relocate_code_to(&cb);
932
933 // Copy the temporary code buffer into the current code buffer.
934 // Basically, do {*this = cb}, except for some control information.
935 this->take_over_code_from(&cb);
936 cb.set_blob(nullptr);
937
938 // Zap the old code buffer contents, to avoid mistakenly using them.
939 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
940 badCodeHeapFreeVal);)
941
942 // Make certain that the new sections are all snugly inside the new blob.
943 debug_only(verify_section_allocation();)
944
945 #ifndef PRODUCT
946 _decode_begin = nullptr; // sanity
947 if (PrintNMethods && (WizardMode || Verbose)) {
948 tty->print("expanded CodeBuffer:");
949 this->print();
950 }
951 #endif //PRODUCT
952 }
953
954 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
955 // Must already have disposed of the old blob somehow.
956 assert(blob() == nullptr, "must be empty");
957 // Take the new blob away from cb.
958 set_blob(cb->blob());
959 // Take over all the section pointers.
960 for (int n = 0; n < (int)SECT_LIMIT; n++) {
961 CodeSection* cb_sect = cb->code_section(n);
962 CodeSection* this_sect = code_section(n);
963 this_sect->take_over_code_from(cb_sect);
964 }
965 _overflow_arena = cb->_overflow_arena;
966 cb->_overflow_arena = nullptr;
967 // Make sure the old cb won't try to use it or free it.
968 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
969 }
970
971 void CodeBuffer::verify_section_allocation() {
972 address tstart = _total_start;
973 if (tstart == badAddress) return; // smashed by set_blob(nullptr)
974 address tend = tstart + _total_size;
975 if (_blob != nullptr) {
976 guarantee(tstart >= _blob->content_begin(), "sanity");
977 guarantee(tend <= _blob->content_end(), "sanity");
978 }
979 // Verify disjointness.
980 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
981 CodeSection* sect = code_section(n);
982 if (!sect->is_allocated() || sect->is_empty()) {
983 continue;
984 }
985 guarantee(_blob == nullptr || is_aligned(sect->start(), sect->alignment()),
986 "start is aligned");
987 for (int m = n + 1; m < (int) SECT_LIMIT; m++) {
988 CodeSection* other = code_section(m);
989 if (!other->is_allocated() || other == sect) {
990 continue;
991 }
992 guarantee(other->disjoint(sect), "sanity");
993 }
994 guarantee(sect->end() <= tend, "sanity");
995 guarantee(sect->end() <= sect->limit(), "sanity");
996 }
997 }
998
999 void CodeBuffer::log_section_sizes(const char* name) {
1000 if (xtty != nullptr) {
1001 ttyLocker ttyl;
1002 // log info about buffer usage
1003 xtty->print_cr("<blob name='%s' total_size='%d'>", name, _total_size);
1004 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
1005 CodeSection* sect = code_section(n);
1006 if (!sect->is_allocated() || sect->is_empty()) continue;
1007 xtty->print_cr("<sect index='%d' capacity='%d' size='%d' remaining='%d'/>",
1008 n, sect->capacity(), sect->size(), sect->remaining());
1009 }
1010 xtty->print_cr("</blob>");
1011 }
1012 }
1013
1014 bool CodeBuffer::finalize_stubs() {
1015 // Record size of code before we generate stubs in instructions section
1016 _main_code_size = _insts.size();
1017 if (_finalize_stubs && !pd_finalize_stubs()) {
1018 // stub allocation failure
1019 return false;
1020 }
1021 _finalize_stubs = false;
1022 return true;
1023 }
1024
1025 void CodeBuffer::shared_stub_to_interp_for(ciMethod* callee, csize_t call_offset) {
1026 if (_shared_stub_to_interp_requests == nullptr) {
1027 _shared_stub_to_interp_requests = new SharedStubToInterpRequests(8);
1028 }
1029 SharedStubToInterpRequest request(callee, call_offset);
1030 _shared_stub_to_interp_requests->push(request);
1031 _finalize_stubs = true;
1032 }
1033
1034 #ifndef PRODUCT
1035 void CodeBuffer::block_comment(ptrdiff_t offset, const char* comment) {
1036 if (_collect_comments) {
1037 const char* str = _asm_remarks.insert(offset, comment);
1038 postcond(str != comment);
1039 }
1040 }
1041
1042 const char* CodeBuffer::code_string(const char* str) {
1043 const char* tmp = _dbg_strings.insert(str);
1044 postcond(tmp != str);
1045 return tmp;
1046 }
1047
1048 void CodeBuffer::decode() {
1049 ttyLocker ttyl;
1050 Disassembler::decode(decode_begin(), insts_end(), tty NOT_PRODUCT(COMMA &asm_remarks()));
1051 _decode_begin = insts_end();
1052 }
1053
1054 void CodeSection::print(const char* name) {
1055 csize_t locs_size = locs_end() - locs_start();
1056 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)",
1057 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity());
1058 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1059 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off());
1060 if (PrintRelocations) {
1061 RelocIterator iter(this);
1062 iter.print();
1063 }
1064 }
1065
1066 void CodeBuffer::print() {
1067 tty->print_cr("CodeBuffer:");
1068 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1069 // print each section
1070 CodeSection* cs = code_section(n);
1071 cs->print(code_section_name(n));
1072 }
1073 }
1074
1075 // ----- CHeapString -----------------------------------------------------------
1076
1077 class CHeapString : public CHeapObj<mtCode> {
1078 public:
1079 CHeapString(const char* str) : _string(os::strdup(str)) {}
1080 ~CHeapString() {
1081 os::free((void*)_string);
1082 _string = nullptr;
1083 }
1084 const char* string() const { return _string; }
1085
1086 private:
1087 const char* _string;
1088 };
1089
1090 // ----- AsmRemarkCollection ---------------------------------------------------
1091
1092 class AsmRemarkCollection : public CHeapObj<mtCode> {
1093 public:
1094 AsmRemarkCollection() : _ref_cnt(1), _remarks(nullptr), _next(nullptr) {}
1095 ~AsmRemarkCollection() {
1096 assert(is_empty(), "Must 'clear()' before deleting!");
1097 assert(_ref_cnt == 0, "No uses must remain when deleting!");
1098 }
1099 AsmRemarkCollection* reuse() {
1100 precond(_ref_cnt > 0);
1101 return _ref_cnt++, this;
1102 }
1103
1104 const char* insert(uint offset, const char* remark);
1105 const char* lookup(uint offset) const;
1106 const char* next(uint offset) const;
1107
1108 bool is_empty() const { return _remarks == nullptr; }
1109 uint clear();
1110
1111 private:
1112 struct Cell : CHeapString {
1113 Cell(const char* remark, uint offset) :
1114 CHeapString(remark), offset(offset), prev(nullptr), next(nullptr) {}
1115 void push_back(Cell* cell) {
1116 Cell* head = this;
1117 Cell* tail = prev;
1118 tail->next = cell;
1119 cell->next = head;
1120 cell->prev = tail;
1121 prev = cell;
1122 }
1123 uint offset;
1124 Cell* prev;
1125 Cell* next;
1126 };
1127 uint _ref_cnt;
1128 Cell* _remarks;
1129 // Using a 'mutable' iteration pointer to allow 'const' on lookup/next (that
1130 // does not change the state of the list per se), supportig a simplistic
1131 // iteration scheme.
1132 mutable Cell* _next;
1133 };
1134
1135 // ----- DbgStringCollection ---------------------------------------------------
1136
1137 class DbgStringCollection : public CHeapObj<mtCode> {
1138 public:
1139 DbgStringCollection() : _ref_cnt(1), _strings(nullptr) {}
1140 ~DbgStringCollection() {
1141 assert(is_empty(), "Must 'clear()' before deleting!");
1142 assert(_ref_cnt == 0, "No uses must remain when deleting!");
1143 }
1144 DbgStringCollection* reuse() {
1145 precond(_ref_cnt > 0);
1146 return _ref_cnt++, this;
1147 }
1148
1149 const char* insert(const char* str);
1150 const char* lookup(const char* str) const;
1151
1152 bool is_empty() const { return _strings == nullptr; }
1153 uint clear();
1154
1155 private:
1156 struct Cell : CHeapString {
1157 Cell(const char* dbgstr) :
1158 CHeapString(dbgstr), prev(nullptr), next(nullptr) {}
1159 void push_back(Cell* cell) {
1160 Cell* head = this;
1161 Cell* tail = prev;
1162 tail->next = cell;
1163 cell->next = head;
1164 cell->prev = tail;
1165 prev = cell;
1166 }
1167 Cell* prev;
1168 Cell* next;
1169 };
1170 uint _ref_cnt;
1171 Cell* _strings;
1172 };
1173
1174 // ----- AsmRemarks ------------------------------------------------------------
1175 //
1176 // Acting as interface to reference counted mapping [offset -> remark], where
1177 // offset is a byte offset into an instruction stream (CodeBuffer, CodeBlob or
1178 // other memory buffer) and remark is a string (comment).
1179 //
1180 AsmRemarks::AsmRemarks() : _remarks(new AsmRemarkCollection()) {
1181 assert(_remarks != nullptr, "Allocation failure!");
1182 }
1183
1184 AsmRemarks::~AsmRemarks() {
1185 assert(_remarks == nullptr, "Must 'clear()' before deleting!");
1186 }
1187
1188 const char* AsmRemarks::insert(uint offset, const char* remstr) {
1189 precond(remstr != nullptr);
1190 return _remarks->insert(offset, remstr);
1191 }
1192
1193 bool AsmRemarks::is_empty() const {
1194 return _remarks->is_empty();
1195 }
1196
1197 void AsmRemarks::share(const AsmRemarks &src) {
1198 precond(is_empty());
1199 clear();
1200 _remarks = src._remarks->reuse();
1201 }
1202
1203 void AsmRemarks::clear() {
1204 if (_remarks->clear() == 0) {
1205 delete _remarks;
1206 }
1207 _remarks = nullptr;
1208 }
1209
1210 uint AsmRemarks::print(uint offset, outputStream* strm) const {
1211 uint count = 0;
1212 const char* prefix = " ;; ";
1213 const char* remstr = _remarks->lookup(offset);
1214 while (remstr != nullptr) {
1215 strm->bol();
1216 strm->print("%s", prefix);
1217 // Don't interpret as format strings since it could contain '%'.
1218 strm->print_raw(remstr);
1219 // Advance to next line iff string didn't contain a cr() at the end.
1220 strm->bol();
1221 remstr = _remarks->next(offset);
1222 count++;
1223 }
1224 return count;
1225 }
1226
1227 // ----- DbgStrings ------------------------------------------------------------
1228 //
1229 // Acting as interface to reference counted collection of (debug) strings used
1230 // in the code generated, and thus requiring a fixed address.
1231 //
1232 DbgStrings::DbgStrings() : _strings(new DbgStringCollection()) {
1233 assert(_strings != nullptr, "Allocation failure!");
1234 }
1235
1236 DbgStrings::~DbgStrings() {
1237 assert(_strings == nullptr, "Must 'clear()' before deleting!");
1238 }
1239
1240 const char* DbgStrings::insert(const char* dbgstr) {
1241 const char* str = _strings->lookup(dbgstr);
1242 return str != nullptr ? str : _strings->insert(dbgstr);
1243 }
1244
1245 bool DbgStrings::is_empty() const {
1246 return _strings->is_empty();
1247 }
1248
1249 void DbgStrings::share(const DbgStrings &src) {
1250 precond(is_empty());
1251 clear();
1252 _strings = src._strings->reuse();
1253 }
1254
1255 void DbgStrings::clear() {
1256 if (_strings->clear() == 0) {
1257 delete _strings;
1258 }
1259 _strings = nullptr;
1260 }
1261
1262 // ----- AsmRemarkCollection ---------------------------------------------------
1263
1264 const char* AsmRemarkCollection::insert(uint offset, const char* remstr) {
1265 precond(remstr != nullptr);
1266 Cell* cell = new Cell { remstr, offset };
1267 if (is_empty()) {
1268 cell->prev = cell;
1269 cell->next = cell;
1270 _remarks = cell;
1271 } else {
1272 _remarks->push_back(cell);
1273 }
1274 return cell->string();
1275 }
1276
1277 const char* AsmRemarkCollection::lookup(uint offset) const {
1278 _next = _remarks;
1279 return next(offset);
1280 }
1281
1282 const char* AsmRemarkCollection::next(uint offset) const {
1283 if (_next != nullptr) {
1284 Cell* i = _next;
1285 do {
1286 if (i->offset == offset) {
1287 _next = i->next == _remarks ? nullptr : i->next;
1288 return i->string();
1289 }
1290 i = i->next;
1291 } while (i != _remarks);
1292 _next = nullptr;
1293 }
1294 return nullptr;
1295 }
1296
1297 uint AsmRemarkCollection::clear() {
1298 precond(_ref_cnt > 0);
1299 if (--_ref_cnt > 0) {
1300 return _ref_cnt;
1301 }
1302 if (!is_empty()) {
1303 uint count = 0;
1304 Cell* i = _remarks;
1305 do {
1306 Cell* next = i->next;
1307 delete i;
1308 i = next;
1309 count++;
1310 } while (i != _remarks);
1311
1312 log_debug(codestrings)("Clear %u asm-remark%s.", count, count == 1 ? "" : "s");
1313 _remarks = nullptr;
1314 }
1315 return 0; // i.e. _ref_cnt == 0
1316 }
1317
1318 // ----- DbgStringCollection ---------------------------------------------------
1319
1320 const char* DbgStringCollection::insert(const char* dbgstr) {
1321 precond(dbgstr != nullptr);
1322 Cell* cell = new Cell { dbgstr };
1323
1324 if (is_empty()) {
1325 cell->prev = cell;
1326 cell->next = cell;
1327 _strings = cell;
1328 } else {
1329 _strings->push_back(cell);
1330 }
1331 return cell->string();
1332 }
1333
1334 const char* DbgStringCollection::lookup(const char* dbgstr) const {
1335 precond(dbgstr != nullptr);
1336 if (_strings != nullptr) {
1337 Cell* i = _strings;
1338 do {
1339 if (strcmp(i->string(), dbgstr) == 0) {
1340 return i->string();
1341 }
1342 i = i->next;
1343 } while (i != _strings);
1344 }
1345 return nullptr;
1346 }
1347
1348 uint DbgStringCollection::clear() {
1349 precond(_ref_cnt > 0);
1350 if (--_ref_cnt > 0) {
1351 return _ref_cnt;
1352 }
1353 if (!is_empty()) {
1354 uint count = 0;
1355 Cell* i = _strings;
1356 do {
1357 Cell* next = i->next;
1358 delete i;
1359 i = next;
1360 count++;
1361 } while (i != _strings);
1362
1363 log_debug(codestrings)("Clear %u dbg-string%s.", count, count == 1 ? "" : "s");
1364 _strings = nullptr;
1365 }
1366 return 0; // i.e. _ref_cnt == 0
1367 }
1368
1369 #endif // not PRODUCT