1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "asm/codeBuffer.hpp"
27 #include "code/oopRecorder.inline.hpp"
28 #include "compiler/disassembler.hpp"
29 #include "oops/methodData.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/icache.hpp"
32 #include "runtime/safepointVerifiers.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/copy.hpp"
35 #include "utilities/xmlstream.hpp"
36
37 // The structure of a CodeSection:
38 //
39 // _start -> +----------------+
40 // | machine code...|
41 // _end -> |----------------|
42 // | |
43 // | (empty) |
44 // | |
45 // | |
46 // +----------------+
47 // _limit -> | |
48 //
49 // _locs_start -> +----------------+
50 // |reloc records...|
51 // |----------------|
52 // _locs_end -> | |
53 // | |
54 // | (empty) |
55 // | |
56 // | |
57 // +----------------+
58 // _locs_limit -> | |
59 // The _end (resp. _limit) pointer refers to the first
60 // unused (resp. unallocated) byte.
61
62 // The structure of the CodeBuffer while code is being accumulated:
63 //
64 // _total_start -> \
65 // _insts._start -> +----------------+
66 // | |
67 // | Code |
68 // | |
69 // _stubs._start -> |----------------|
70 // | |
71 // | Stubs | (also handlers for deopt/exception)
72 // | |
73 // _consts._start -> |----------------|
74 // | |
75 // | Constants |
76 // | |
77 // +----------------+
78 // + _total_size -> | |
79 //
80 // When the code and relocations are copied to the code cache,
81 // the empty parts of each section are removed, and everything
82 // is copied into contiguous locations.
83
84 typedef CodeBuffer::csize_t csize_t; // file-local definition
85
86 // External buffer, in a predefined CodeBlob.
87 // Important: The code_start must be taken exactly, and not realigned.
88 CodeBuffer::CodeBuffer(CodeBlob* blob) {
89 initialize_misc("static buffer");
90 initialize(blob->content_begin(), blob->content_size());
91 verify_section_allocation();
92 }
93
94 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
95 // Compute maximal alignment.
96 int align = _insts.alignment();
97 // Always allow for empty slop around each section.
98 int slop = (int) CodeSection::end_slop();
99
100 assert(blob() == NULL, "only once");
101 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1)));
102 if (blob() == NULL) {
103 // The assembler constructor will throw a fatal on an empty CodeBuffer.
104 return; // caller must test this
105 }
106
107 // Set up various pointers into the blob.
108 initialize(_total_start, _total_size);
109
110 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
111
112 pd_initialize();
113
114 if (locs_size != 0) {
115 _insts.initialize_locs(locs_size / sizeof(relocInfo));
116 }
117
118 verify_section_allocation();
119 }
120
121
122 CodeBuffer::~CodeBuffer() {
123 verify_section_allocation();
124
125 // If we allocate our code buffer from the CodeCache
126 // via a BufferBlob, and it's not permanent, then
127 // free the BufferBlob.
128 // The rest of the memory will be freed when the ResourceObj
129 // is released.
130 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) {
131 // Previous incarnations of this buffer are held live, so that internal
132 // addresses constructed before expansions will not be confused.
133 cb->free_blob();
134 }
135
136 // free any overflow storage
137 delete _overflow_arena;
138
139 // Claim is that stack allocation ensures resources are cleaned up.
140 // This is resource clean up, let's hope that all were properly copied out.
141 free_strings();
142
143 #ifdef ASSERT
144 // Save allocation type to execute assert in ~ResourceObj()
145 // which is called after this destructor.
146 assert(_default_oop_recorder.allocated_on_stack(), "should be embedded object");
147 ResourceObj::allocation_type at = _default_oop_recorder.get_allocation_type();
148 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue);
149 ResourceObj::set_allocation_type((address)(&_default_oop_recorder), at);
150 #endif
151 }
152
153 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
154 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
155 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen
156 _oop_recorder = r;
157 }
158
159 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
160 assert(cs != &_insts, "insts is the memory provider, not the consumer");
161 csize_t slop = CodeSection::end_slop(); // margin between sections
162 int align = cs->alignment();
163 assert(is_power_of_2(align), "sanity");
164 address start = _insts._start;
165 address limit = _insts._limit;
166 address middle = limit - size;
167 middle -= (intptr_t)middle & (align-1); // align the division point downward
168 guarantee(middle - slop > start, "need enough space to divide up");
169 _insts._limit = middle - slop; // subtract desired space, plus slop
170 cs->initialize(middle, limit - middle);
171 assert(cs->start() == middle, "sanity");
172 assert(cs->limit() == limit, "sanity");
173 // give it some relocations to start with, if the main section has them
174 if (_insts.has_locs()) cs->initialize_locs(1);
175 }
176
177 void CodeBuffer::freeze_section(CodeSection* cs) {
178 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1);
179 csize_t frozen_size = cs->size();
180 if (next_cs != NULL) {
181 frozen_size = next_cs->align_at_start(frozen_size);
182 }
183 address old_limit = cs->limit();
184 address new_limit = cs->start() + frozen_size;
185 relocInfo* old_locs_limit = cs->locs_limit();
186 relocInfo* new_locs_limit = cs->locs_end();
187 // Patch the limits.
188 cs->_limit = new_limit;
189 cs->_locs_limit = new_locs_limit;
190 cs->_frozen = true;
191 if (next_cs != NULL && !next_cs->is_allocated() && !next_cs->is_frozen()) {
192 // Give remaining buffer space to the following section.
193 next_cs->initialize(new_limit, old_limit - new_limit);
194 next_cs->initialize_shared_locs(new_locs_limit,
195 old_locs_limit - new_locs_limit);
196 }
197 }
198
199 void CodeBuffer::set_blob(BufferBlob* blob) {
200 _blob = blob;
201 if (blob != NULL) {
202 address start = blob->content_begin();
203 address end = blob->content_end();
204 // Round up the starting address.
205 int align = _insts.alignment();
206 start += (-(intptr_t)start) & (align-1);
207 _total_start = start;
208 _total_size = end - start;
209 } else {
210 #ifdef ASSERT
211 // Clean out dangling pointers.
212 _total_start = badAddress;
213 _consts._start = _consts._end = badAddress;
214 _insts._start = _insts._end = badAddress;
215 _stubs._start = _stubs._end = badAddress;
216 #endif //ASSERT
217 }
218 }
219
220 void CodeBuffer::free_blob() {
221 if (_blob != NULL) {
222 BufferBlob::free(_blob);
223 set_blob(NULL);
224 }
225 }
226
227 const char* CodeBuffer::code_section_name(int n) {
228 #ifdef PRODUCT
229 return NULL;
230 #else //PRODUCT
231 switch (n) {
232 case SECT_CONSTS: return "consts";
233 case SECT_INSTS: return "insts";
234 case SECT_STUBS: return "stubs";
235 default: return NULL;
236 }
237 #endif //PRODUCT
238 }
239
240 int CodeBuffer::section_index_of(address addr) const {
241 for (int n = 0; n < (int)SECT_LIMIT; n++) {
242 const CodeSection* cs = code_section(n);
243 if (cs->allocates(addr)) return n;
244 }
245 return SECT_NONE;
246 }
247
248 int CodeBuffer::locator(address addr) const {
249 for (int n = 0; n < (int)SECT_LIMIT; n++) {
250 const CodeSection* cs = code_section(n);
251 if (cs->allocates(addr)) {
252 return locator(addr - cs->start(), n);
253 }
254 }
255 return -1;
256 }
257
258 address CodeBuffer::locator_address(int locator) const {
259 if (locator < 0) return NULL;
260 address start = code_section(locator_sect(locator))->start();
261 return start + locator_pos(locator);
262 }
263
264 bool CodeBuffer::is_backward_branch(Label& L) {
265 return L.is_bound() && insts_end() <= locator_address(L.loc());
266 }
267
268 address CodeBuffer::decode_begin() {
269 address begin = _insts.start();
270 if (_decode_begin != NULL && _decode_begin > begin)
271 begin = _decode_begin;
272 return begin;
273 }
274
275
276 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
277 if (_overflow_arena == NULL) {
278 _overflow_arena = new (mtCode) Arena(mtCode);
279 }
280 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
281 }
282
283
284 // Helper function for managing labels and their target addresses.
285 // Returns a sensible address, and if it is not the label's final
286 // address, notes the dependency (at 'branch_pc') on the label.
287 address CodeSection::target(Label& L, address branch_pc) {
288 if (L.is_bound()) {
289 int loc = L.loc();
290 if (index() == CodeBuffer::locator_sect(loc)) {
291 return start() + CodeBuffer::locator_pos(loc);
292 } else {
293 return outer()->locator_address(loc);
294 }
295 } else {
296 assert(allocates2(branch_pc), "sanity");
297 address base = start();
298 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
299 L.add_patch_at(outer(), patch_loc);
300
301 // Need to return a pc, doesn't matter what it is since it will be
302 // replaced during resolution later.
303 // Don't return NULL or badAddress, since branches shouldn't overflow.
304 // Don't return base either because that could overflow displacements
305 // for shorter branches. It will get checked when bound.
306 return branch_pc;
307 }
308 }
309
310 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) {
311 RelocationHolder rh;
312 switch (rtype) {
313 case relocInfo::none: return;
314 case relocInfo::opt_virtual_call_type: {
315 rh = opt_virtual_call_Relocation::spec(method_index);
316 break;
317 }
318 case relocInfo::static_call_type: {
319 rh = static_call_Relocation::spec(method_index);
320 break;
321 }
322 case relocInfo::virtual_call_type: {
323 assert(method_index == 0, "resolved method overriding is not supported");
324 rh = Relocation::spec_simple(rtype);
325 break;
326 }
327 default: {
328 rh = Relocation::spec_simple(rtype);
329 break;
330 }
331 }
332 relocate(at, rh, format);
333 }
334
335 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
336 // Do not relocate in scratch buffers.
337 if (scratch_emit()) { return; }
338 Relocation* reloc = spec.reloc();
339 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
340 if (rtype == relocInfo::none) return;
341
342 // The assertion below has been adjusted, to also work for
343 // relocation for fixup. Sometimes we want to put relocation
344 // information for the next instruction, since it will be patched
345 // with a call.
346 assert(start() <= at && at <= end()+1,
347 "cannot relocate data outside code boundaries");
348
349 if (!has_locs()) {
350 // no space for relocation information provided => code cannot be
351 // relocated. Make sure that relocate is only called with rtypes
352 // that can be ignored for this kind of code.
353 assert(rtype == relocInfo::none ||
354 rtype == relocInfo::runtime_call_type ||
355 rtype == relocInfo::internal_word_type||
356 rtype == relocInfo::section_word_type ||
357 rtype == relocInfo::external_word_type,
358 "code needs relocation information");
359 // leave behind an indication that we attempted a relocation
360 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
361 return;
362 }
363
364 // Advance the point, noting the offset we'll have to record.
365 csize_t offset = at - locs_point();
366 set_locs_point(at);
367
368 // Test for a couple of overflow conditions; maybe expand the buffer.
369 relocInfo* end = locs_end();
370 relocInfo* req = end + relocInfo::length_limit;
371 // Check for (potential) overflow
372 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
373 req += (uint)offset / (uint)relocInfo::offset_limit();
374 if (req >= locs_limit()) {
375 // Allocate or reallocate.
376 expand_locs(locs_count() + (req - end));
377 // reload pointer
378 end = locs_end();
379 }
380 }
381
382 // If the offset is giant, emit filler relocs, of type 'none', but
383 // each carrying the largest possible offset, to advance the locs_point.
384 while (offset >= relocInfo::offset_limit()) {
385 assert(end < locs_limit(), "adjust previous paragraph of code");
386 *end++ = filler_relocInfo();
387 offset -= filler_relocInfo().addr_offset();
388 }
389
390 // If it's a simple reloc with no data, we'll just write (rtype | offset).
391 (*end) = relocInfo(rtype, offset, format);
392
393 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
394 end->initialize(this, reloc);
395 }
396
397 void CodeSection::initialize_locs(int locs_capacity) {
398 assert(_locs_start == NULL, "only one locs init step, please");
399 // Apply a priori lower limits to relocation size:
400 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
401 if (locs_capacity < min_locs) locs_capacity = min_locs;
402 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
403 _locs_start = locs_start;
404 _locs_end = locs_start;
405 _locs_limit = locs_start + locs_capacity;
406 _locs_own = true;
407 }
408
409 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
410 assert(_locs_start == NULL, "do this before locs are allocated");
411 // Internal invariant: locs buf must be fully aligned.
412 // See copy_relocations_to() below.
413 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
414 ++buf; --length;
415 }
416 if (length > 0) {
417 _locs_start = buf;
418 _locs_end = buf;
419 _locs_limit = buf + length;
420 _locs_own = false;
421 }
422 }
423
424 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
425 int lcount = source_cs->locs_count();
426 if (lcount != 0) {
427 initialize_shared_locs(source_cs->locs_start(), lcount);
428 _locs_end = _locs_limit = _locs_start + lcount;
429 assert(is_allocated(), "must have copied code already");
430 set_locs_point(start() + source_cs->locs_point_off());
431 }
432 assert(this->locs_count() == source_cs->locs_count(), "sanity");
433 }
434
435 void CodeSection::expand_locs(int new_capacity) {
436 if (_locs_start == NULL) {
437 initialize_locs(new_capacity);
438 return;
439 } else {
440 int old_count = locs_count();
441 int old_capacity = locs_capacity();
442 if (new_capacity < old_capacity * 2)
443 new_capacity = old_capacity * 2;
444 relocInfo* locs_start;
445 if (_locs_own) {
446 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
447 } else {
448 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
449 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
450 _locs_own = true;
451 }
452 _locs_start = locs_start;
453 _locs_end = locs_start + old_count;
454 _locs_limit = locs_start + new_capacity;
455 }
456 }
457
458
459 /// Support for emitting the code to its final location.
460 /// The pattern is the same for all functions.
461 /// We iterate over all the sections, padding each to alignment.
462
463 csize_t CodeBuffer::total_content_size() const {
464 csize_t size_so_far = 0;
465 for (int n = 0; n < (int)SECT_LIMIT; n++) {
466 const CodeSection* cs = code_section(n);
467 if (cs->is_empty()) continue; // skip trivial section
468 size_so_far = cs->align_at_start(size_so_far);
469 size_so_far += cs->size();
470 }
471 return size_so_far;
472 }
473
474 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
475 address buf = dest->_total_start;
476 csize_t buf_offset = 0;
477 assert(dest->_total_size >= total_content_size(), "must be big enough");
478
479 {
480 // not sure why this is here, but why not...
481 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
482 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
483 }
484
485 const CodeSection* prev_cs = NULL;
486 CodeSection* prev_dest_cs = NULL;
487
488 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
489 // figure compact layout of each section
490 const CodeSection* cs = code_section(n);
491 csize_t csize = cs->size();
492
493 CodeSection* dest_cs = dest->code_section(n);
494 if (!cs->is_empty()) {
495 // Compute initial padding; assign it to the previous non-empty guy.
496 // Cf. figure_expanded_capacities.
497 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
498 if (prev_dest_cs != NULL) {
499 if (padding != 0) {
500 buf_offset += padding;
501 prev_dest_cs->_limit += padding;
502 }
503 } else {
504 guarantee(padding == 0, "In first iteration no padding should be needed.");
505 }
506 #ifdef ASSERT
507 if (prev_cs != NULL && prev_cs->is_frozen() && n < (SECT_LIMIT - 1)) {
508 // Make sure the ends still match up.
509 // This is important because a branch in a frozen section
510 // might target code in a following section, via a Label,
511 // and without a relocation record. See Label::patch_instructions.
512 address dest_start = buf+buf_offset;
513 csize_t start2start = cs->start() - prev_cs->start();
514 csize_t dest_start2start = dest_start - prev_dest_cs->start();
515 assert(start2start == dest_start2start, "cannot stretch frozen sect");
516 }
517 #endif //ASSERT
518 prev_dest_cs = dest_cs;
519 prev_cs = cs;
520 }
521
522 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert
523 dest_cs->initialize(buf+buf_offset, csize);
524 dest_cs->set_end(buf+buf_offset+csize);
525 assert(dest_cs->is_allocated(), "must always be allocated");
526 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
527
528 buf_offset += csize;
529 }
530
531 // Done calculating sections; did it come out to the right end?
532 assert(buf_offset == total_content_size(), "sanity");
533 dest->verify_section_allocation();
534 }
535
536 // Append an oop reference that keeps the class alive.
537 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) {
538 oop cl = k->klass_holder();
539 if (cl != NULL && !oops->contains(cl)) {
540 oops->append(cl);
541 }
542 }
543
544 void CodeBuffer::finalize_oop_references(const methodHandle& mh) {
545 NoSafepointVerifier nsv;
546
547 GrowableArray<oop> oops;
548
549 // Make sure that immediate metadata records something in the OopRecorder
550 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
551 // pull code out of each section
552 CodeSection* cs = code_section(n);
553 if (cs->is_empty()) continue; // skip trivial section
554 RelocIterator iter(cs);
555 while (iter.next()) {
556 if (iter.type() == relocInfo::metadata_type) {
557 metadata_Relocation* md = iter.metadata_reloc();
558 if (md->metadata_is_immediate()) {
559 Metadata* m = md->metadata_value();
560 if (oop_recorder()->is_real(m)) {
561 if (m->is_methodData()) {
562 m = ((MethodData*)m)->method();
563 }
564 if (m->is_method()) {
565 m = ((Method*)m)->method_holder();
566 }
567 if (m->is_klass()) {
568 append_oop_references(&oops, (Klass*)m);
569 } else {
570 // XXX This will currently occur for MDO which don't
571 // have a backpointer. This has to be fixed later.
572 m->print();
573 ShouldNotReachHere();
574 }
575 }
576 }
577 }
578 }
579 }
580
581 if (!oop_recorder()->is_unused()) {
582 for (int i = 0; i < oop_recorder()->metadata_count(); i++) {
583 Metadata* m = oop_recorder()->metadata_at(i);
584 if (oop_recorder()->is_real(m)) {
585 if (m->is_methodData()) {
586 m = ((MethodData*)m)->method();
587 }
588 if (m->is_method()) {
589 m = ((Method*)m)->method_holder();
590 }
591 if (m->is_klass()) {
592 append_oop_references(&oops, (Klass*)m);
593 } else {
594 m->print();
595 ShouldNotReachHere();
596 }
597 }
598 }
599
600 }
601
602 // Add the class loader of Method* for the nmethod itself
603 append_oop_references(&oops, mh->method_holder());
604
605 // Add any oops that we've found
606 Thread* thread = Thread::current();
607 for (int i = 0; i < oops.length(); i++) {
608 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i)));
609 }
610 }
611
612
613
614 csize_t CodeBuffer::total_offset_of(const CodeSection* cs) const {
615 csize_t size_so_far = 0;
616 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
617 const CodeSection* cur_cs = code_section(n);
618 if (!cur_cs->is_empty()) {
619 size_so_far = cur_cs->align_at_start(size_so_far);
620 }
621 if (cur_cs->index() == cs->index()) {
622 return size_so_far;
623 }
624 size_so_far += cur_cs->size();
625 }
626 ShouldNotReachHere();
627 return -1;
628 }
629
630 csize_t CodeBuffer::total_relocation_size() const {
631 csize_t total = copy_relocations_to(NULL); // dry run only
632 return (csize_t) align_up(total, HeapWordSize);
633 }
634
635 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const {
636 csize_t buf_offset = 0;
637 csize_t code_end_so_far = 0;
638 csize_t code_point_so_far = 0;
639
640 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
641 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
642
643 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
644 if (only_inst && (n != (int)SECT_INSTS)) {
645 // Need only relocation info for code.
646 continue;
647 }
648 // pull relocs out of each section
649 const CodeSection* cs = code_section(n);
650 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
651 if (cs->is_empty()) continue; // skip trivial section
652 relocInfo* lstart = cs->locs_start();
653 relocInfo* lend = cs->locs_end();
654 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
655 csize_t csize = cs->size();
656 code_end_so_far = cs->align_at_start(code_end_so_far);
657
658 if (lsize > 0) {
659 // Figure out how to advance the combined relocation point
660 // first to the beginning of this section.
661 // We'll insert one or more filler relocs to span that gap.
662 // (Don't bother to improve this by editing the first reloc's offset.)
663 csize_t new_code_point = code_end_so_far;
664 for (csize_t jump;
665 code_point_so_far < new_code_point;
666 code_point_so_far += jump) {
667 jump = new_code_point - code_point_so_far;
668 relocInfo filler = filler_relocInfo();
669 if (jump >= filler.addr_offset()) {
670 jump = filler.addr_offset();
671 } else { // else shrink the filler to fit
672 filler = relocInfo(relocInfo::none, jump);
673 }
674 if (buf != NULL) {
675 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
676 *(relocInfo*)(buf+buf_offset) = filler;
677 }
678 buf_offset += sizeof(filler);
679 }
680
681 // Update code point and end to skip past this section:
682 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
683 assert(code_point_so_far <= last_code_point, "sanity");
684 code_point_so_far = last_code_point; // advance past this guy's relocs
685 }
686 code_end_so_far += csize; // advance past this guy's instructions too
687
688 // Done with filler; emit the real relocations:
689 if (buf != NULL && lsize != 0) {
690 assert(buf_offset + lsize <= buf_limit, "target in bounds");
691 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
692 if (buf_offset % HeapWordSize == 0) {
693 // Use wordwise copies if possible:
694 Copy::disjoint_words((HeapWord*)lstart,
695 (HeapWord*)(buf+buf_offset),
696 (lsize + HeapWordSize-1) / HeapWordSize);
697 } else {
698 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
699 }
700 }
701 buf_offset += lsize;
702 }
703
704 // Align end of relocation info in target.
705 while (buf_offset % HeapWordSize != 0) {
706 if (buf != NULL) {
707 relocInfo padding = relocInfo(relocInfo::none, 0);
708 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
709 *(relocInfo*)(buf+buf_offset) = padding;
710 }
711 buf_offset += sizeof(relocInfo);
712 }
713
714 assert(only_inst || code_end_so_far == total_content_size(), "sanity");
715
716 return buf_offset;
717 }
718
719 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
720 address buf = NULL;
721 csize_t buf_offset = 0;
722 csize_t buf_limit = 0;
723
724 if (dest != NULL) {
725 buf = (address)dest->relocation_begin();
726 buf_limit = (address)dest->relocation_end() - buf;
727 }
728 // if dest == NULL, this is just the sizing pass
729 //
730 buf_offset = copy_relocations_to(buf, buf_limit, false);
731
732 return buf_offset;
733 }
734
735 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
736 #ifndef PRODUCT
737 if (PrintNMethods && (WizardMode || Verbose)) {
738 tty->print("done with CodeBuffer:");
739 ((CodeBuffer*)this)->print();
740 }
741 #endif //PRODUCT
742
743 CodeBuffer dest(dest_blob);
744 assert(dest_blob->content_size() >= total_content_size(), "good sizing");
745 this->compute_final_layout(&dest);
746
747 // Set beginning of constant table before relocating.
748 dest_blob->set_ctable_begin(dest.consts()->start());
749
750 relocate_code_to(&dest);
751
752 // transfer strings and comments from buffer to blob
753 dest_blob->set_strings(_code_strings);
754
755 // Done moving code bytes; were they the right size?
756 assert((int)align_up(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity");
757
758 // Flush generated code
759 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size());
760 }
761
762 // Move all my code into another code buffer. Consult applicable
763 // relocs to repair embedded addresses. The layout in the destination
764 // CodeBuffer is different to the source CodeBuffer: the destination
765 // CodeBuffer gets the final layout (consts, insts, stubs in order of
766 // ascending address).
767 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
768 address dest_end = dest->_total_start + dest->_total_size;
769 address dest_filled = NULL;
770 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
771 // pull code out of each section
772 const CodeSection* cs = code_section(n);
773 if (cs->is_empty()) continue; // skip trivial section
774 CodeSection* dest_cs = dest->code_section(n);
775 assert(cs->size() == dest_cs->size(), "sanity");
776 csize_t usize = dest_cs->size();
777 csize_t wsize = align_up(usize, HeapWordSize);
778 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
779 // Copy the code as aligned machine words.
780 // This may also include an uninitialized partial word at the end.
781 Copy::disjoint_words((HeapWord*)cs->start(),
782 (HeapWord*)dest_cs->start(),
783 wsize / HeapWordSize);
784
785 if (dest->blob() == NULL) {
786 // Destination is a final resting place, not just another buffer.
787 // Normalize uninitialized bytes in the final padding.
788 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
789 Assembler::code_fill_byte());
790 }
791 // Keep track of the highest filled address
792 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining());
793
794 assert(cs->locs_start() != (relocInfo*)badAddress,
795 "this section carries no reloc storage, but reloc was attempted");
796
797 // Make the new code copy use the old copy's relocations:
798 dest_cs->initialize_locs_from(cs);
799 }
800
801 // Do relocation after all sections are copied.
802 // This is necessary if the code uses constants in stubs, which are
803 // relocated when the corresponding instruction in the code (e.g., a
804 // call) is relocated. Stubs are placed behind the main code
805 // section, so that section has to be copied before relocating.
806 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
807 // pull code out of each section
808 const CodeSection* cs = code_section(n);
809 if (cs->is_empty()) continue; // skip trivial section
810 CodeSection* dest_cs = dest->code_section(n);
811 { // Repair the pc relative information in the code after the move
812 RelocIterator iter(dest_cs);
813 while (iter.next()) {
814 iter.reloc()->fix_relocation_after_move(this, dest);
815 }
816 }
817 }
818
819 if (dest->blob() == NULL && dest_filled != NULL) {
820 // Destination is a final resting place, not just another buffer.
821 // Normalize uninitialized bytes in the final padding.
822 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,
823 Assembler::code_fill_byte());
824
825 }
826 }
827
828 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
829 csize_t amount,
830 csize_t* new_capacity) {
831 csize_t new_total_cap = 0;
832
833 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
834 const CodeSection* sect = code_section(n);
835
836 if (!sect->is_empty()) {
837 // Compute initial padding; assign it to the previous section,
838 // even if it's empty (e.g. consts section can be empty).
839 // Cf. compute_final_layout
840 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
841 if (padding != 0) {
842 new_total_cap += padding;
843 assert(n - 1 >= SECT_FIRST, "sanity");
844 new_capacity[n - 1] += padding;
845 }
846 }
847
848 csize_t exp = sect->size(); // 100% increase
849 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
850 if (sect == which_cs) {
851 if (exp < amount) exp = amount;
852 if (StressCodeBuffers) exp = amount; // expand only slightly
853 } else if (n == SECT_INSTS) {
854 // scale down inst increases to a more modest 25%
855 exp = 4*K + ((exp - 4*K) >> 2);
856 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
857 } else if (sect->is_empty()) {
858 // do not grow an empty secondary section
859 exp = 0;
860 }
861 // Allow for inter-section slop:
862 exp += CodeSection::end_slop();
863 csize_t new_cap = sect->size() + exp;
864 if (new_cap < sect->capacity()) {
865 // No need to expand after all.
866 new_cap = sect->capacity();
867 }
868 new_capacity[n] = new_cap;
869 new_total_cap += new_cap;
870 }
871
872 return new_total_cap;
873 }
874
875 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
876 #ifndef PRODUCT
877 if (PrintNMethods && (WizardMode || Verbose)) {
878 tty->print("expanding CodeBuffer:");
879 this->print();
880 }
881
882 if (StressCodeBuffers && blob() != NULL) {
883 static int expand_count = 0;
884 if (expand_count >= 0) expand_count += 1;
885 if (expand_count > 100 && is_power_of_2(expand_count)) {
886 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
887 // simulate an occasional allocation failure:
888 free_blob();
889 }
890 }
891 #endif //PRODUCT
892
893 // Resizing must be allowed
894 {
895 if (blob() == NULL) return; // caller must check for blob == NULL
896 for (int n = 0; n < (int)SECT_LIMIT; n++) {
897 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen");
898 }
899 }
900
901 // Figure new capacity for each section.
902 csize_t new_capacity[SECT_LIMIT];
903 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT);
904 csize_t new_total_cap
905 = figure_expanded_capacities(which_cs, amount, new_capacity);
906
907 // Create a new (temporary) code buffer to hold all the new data
908 CodeBuffer cb(name(), new_total_cap, 0);
909 if (cb.blob() == NULL) {
910 // Failed to allocate in code cache.
911 free_blob();
912 return;
913 }
914
915 // Create an old code buffer to remember which addresses used to go where.
916 // This will be useful when we do final assembly into the code cache,
917 // because we will need to know how to warp any internal address that
918 // has been created at any time in this CodeBuffer's past.
919 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
920 bxp->take_over_code_from(this); // remember the old undersized blob
921 DEBUG_ONLY(this->_blob = NULL); // silence a later assert
922 bxp->_before_expand = this->_before_expand;
923 this->_before_expand = bxp;
924
925 // Give each section its required (expanded) capacity.
926 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) {
927 CodeSection* cb_sect = cb.code_section(n);
928 CodeSection* this_sect = code_section(n);
929 if (new_capacity[n] == 0) continue; // already nulled out
930 if (n != SECT_INSTS) {
931 cb.initialize_section_size(cb_sect, new_capacity[n]);
932 }
933 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
934 address cb_start = cb_sect->start();
935 cb_sect->set_end(cb_start + this_sect->size());
936 if (this_sect->mark() == NULL) {
937 cb_sect->clear_mark();
938 } else {
939 cb_sect->set_mark(cb_start + this_sect->mark_off());
940 }
941 }
942
943 // Needs to be initialized when calling fix_relocation_after_move.
944 cb.blob()->set_ctable_begin(cb.consts()->start());
945
946 // Move all the code and relocations to the new blob:
947 relocate_code_to(&cb);
948
949 // Copy the temporary code buffer into the current code buffer.
950 // Basically, do {*this = cb}, except for some control information.
951 this->take_over_code_from(&cb);
952 cb.set_blob(NULL);
953
954 // Zap the old code buffer contents, to avoid mistakenly using them.
955 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
956 badCodeHeapFreeVal));
957
958 _decode_begin = NULL; // sanity
959
960 // Make certain that the new sections are all snugly inside the new blob.
961 verify_section_allocation();
962
963 #ifndef PRODUCT
964 if (PrintNMethods && (WizardMode || Verbose)) {
965 tty->print("expanded CodeBuffer:");
966 this->print();
967 }
968 #endif //PRODUCT
969 }
970
971 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
972 // Must already have disposed of the old blob somehow.
973 assert(blob() == NULL, "must be empty");
974 // Take the new blob away from cb.
975 set_blob(cb->blob());
976 // Take over all the section pointers.
977 for (int n = 0; n < (int)SECT_LIMIT; n++) {
978 CodeSection* cb_sect = cb->code_section(n);
979 CodeSection* this_sect = code_section(n);
980 this_sect->take_over_code_from(cb_sect);
981 }
982 _overflow_arena = cb->_overflow_arena;
983 // Make sure the old cb won't try to use it or free it.
984 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
985 }
986
987 void CodeBuffer::verify_section_allocation() {
988 address tstart = _total_start;
989 if (tstart == badAddress) return; // smashed by set_blob(NULL)
990 address tend = tstart + _total_size;
991 if (_blob != NULL) {
992
993 guarantee(tstart >= _blob->content_begin(), "sanity");
994 guarantee(tend <= _blob->content_end(), "sanity");
995 }
996 // Verify disjointness.
997 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
998 CodeSection* sect = code_section(n);
999 if (!sect->is_allocated() || sect->is_empty()) continue;
1000 guarantee((intptr_t)sect->start() % sect->alignment() == 0
1001 || sect->is_empty() || _blob == NULL,
1002 "start is aligned");
1003 for (int m = (int) SECT_FIRST; m < (int) SECT_LIMIT; m++) {
1004 CodeSection* other = code_section(m);
1005 if (!other->is_allocated() || other == sect) continue;
1006 guarantee(!other->contains(sect->start() ), "sanity");
1007 // limit is an exclusive address and can be the start of another
1008 // section.
1009 guarantee(!other->contains(sect->limit() - 1), "sanity");
1010 }
1011 guarantee(sect->end() <= tend, "sanity");
1012 guarantee(sect->end() <= sect->limit(), "sanity");
1013 }
1014 }
1015
1016 void CodeBuffer::log_section_sizes(const char* name) {
1017 if (xtty != NULL) {
1018 ttyLocker ttyl;
1019 // log info about buffer usage
1020 xtty->print_cr("<blob name='%s' size='%d'>", name, _total_size);
1021 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
1022 CodeSection* sect = code_section(n);
1023 if (!sect->is_allocated() || sect->is_empty()) continue;
1024 xtty->print_cr("<sect index='%d' size='" SIZE_FORMAT "' free='" SIZE_FORMAT "'/>",
1025 n, sect->limit() - sect->start(), sect->limit() - sect->end());
1026 }
1027 xtty->print_cr("</blob>");
1028 }
1029 }
1030
1031 #ifndef PRODUCT
1032
1033 void CodeSection::decode() {
1034 Disassembler::decode(start(), end());
1035 }
1036
1037 void CodeBuffer::block_comment(intptr_t offset, const char * comment) {
1038 _code_strings.add_comment(offset, comment);
1039 }
1040
1041 const char* CodeBuffer::code_string(const char* str) {
1042 return _code_strings.add_string(str);
1043 }
1044
1045 class CodeString: public CHeapObj<mtCode> {
1046 private:
1047 friend class CodeStrings;
1048 const char * _string;
1049 CodeString* _next;
1050 intptr_t _offset;
1051
1052 ~CodeString() {
1053 assert(_next == NULL, "wrong interface for freeing list");
1054 os::free((void*)_string);
1055 }
1056
1057 bool is_comment() const { return _offset >= 0; }
1058
1059 public:
1060 CodeString(const char * string, intptr_t offset = -1)
1061 : _next(NULL), _offset(offset) {
1062 _string = os::strdup(string, mtCode);
1063 }
1064
1065 const char * string() const { return _string; }
1066 intptr_t offset() const { assert(_offset >= 0, "offset for non comment?"); return _offset; }
1067 CodeString* next() const { return _next; }
1068
1069 void set_next(CodeString* next) { _next = next; }
1070
1071 CodeString* first_comment() {
1072 if (is_comment()) {
1073 return this;
1074 } else {
1075 return next_comment();
1076 }
1077 }
1078 CodeString* next_comment() const {
1079 CodeString* s = _next;
1080 while (s != NULL && !s->is_comment()) {
1081 s = s->_next;
1082 }
1083 return s;
1084 }
1085 };
1086
1087 CodeString* CodeStrings::find(intptr_t offset) const {
1088 CodeString* a = _strings->first_comment();
1089 while (a != NULL && a->offset() != offset) {
1090 a = a->next_comment();
1091 }
1092 return a;
1093 }
1094
1095 // Convenience for add_comment.
1096 CodeString* CodeStrings::find_last(intptr_t offset) const {
1097 CodeString* a = find(offset);
1098 if (a != NULL) {
1099 CodeString* c = NULL;
1100 while (((c = a->next_comment()) != NULL) && (c->offset() == offset)) {
1101 a = c;
1102 }
1103 }
1104 return a;
1105 }
1106
1107 void CodeStrings::add_comment(intptr_t offset, const char * comment) {
1108 check_valid();
1109 CodeString* c = new CodeString(comment, offset);
1110 CodeString* inspos = (_strings == NULL) ? NULL : find_last(offset);
1111
1112 if (inspos) {
1113 // insert after already existing comments with same offset
1114 c->set_next(inspos->next());
1115 inspos->set_next(c);
1116 } else {
1117 // no comments with such offset, yet. Insert before anything else.
1118 c->set_next(_strings);
1119 _strings = c;
1120 }
1121 }
1122
1123 void CodeStrings::assign(CodeStrings& other) {
1124 other.check_valid();
1125 assert(is_null(), "Cannot assign onto non-empty CodeStrings");
1126 _strings = other._strings;
1127 #ifdef ASSERT
1128 _defunct = false;
1129 #endif
1130 other.set_null_and_invalidate();
1131 }
1132
1133 // Deep copy of CodeStrings for consistent memory management.
1134 // Only used for actual disassembly so this is cheaper than reference counting
1135 // for the "normal" fastdebug case.
1136 void CodeStrings::copy(CodeStrings& other) {
1137 other.check_valid();
1138 check_valid();
1139 assert(is_null(), "Cannot copy onto non-empty CodeStrings");
1140 CodeString* n = other._strings;
1141 CodeString** ps = &_strings;
1142 while (n != NULL) {
1143 *ps = new CodeString(n->string(),n->offset());
1144 ps = &((*ps)->_next);
1145 n = n->next();
1146 }
1147 }
1148
1149 const char* CodeStrings::_prefix = " ;; "; // default: can be changed via set_prefix
1150
1151 void CodeStrings::print_block_comment(outputStream* stream, intptr_t offset) const {
1152 check_valid();
1153 if (_strings != NULL) {
1154 CodeString* c = find(offset);
1155 while (c && c->offset() == offset) {
1156 stream->bol();
1157 stream->print("%s", _prefix);
1158 // Don't interpret as format strings since it could contain %
1159 stream->print_raw_cr(c->string());
1160 c = c->next_comment();
1161 }
1162 }
1163 }
1164
1165 // Also sets isNull()
1166 void CodeStrings::free() {
1167 CodeString* n = _strings;
1168 while (n) {
1169 // unlink the node from the list saving a pointer to the next
1170 CodeString* p = n->next();
1171 n->set_next(NULL);
1172 delete n;
1173 n = p;
1174 }
1175 set_null_and_invalidate();
1176 }
1177
1178 const char* CodeStrings::add_string(const char * string) {
1179 check_valid();
1180 CodeString* s = new CodeString(string);
1181 s->set_next(_strings);
1182 _strings = s;
1183 assert(s->string() != NULL, "should have a string");
1184 return s->string();
1185 }
1186
1187 void CodeBuffer::decode() {
1188 ttyLocker ttyl;
1189 Disassembler::decode(decode_begin(), insts_end());
1190 _decode_begin = insts_end();
1191 }
1192
1193 void CodeSection::print(const char* name) {
1194 csize_t locs_size = locs_end() - locs_start();
1195 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s",
1196 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity(),
1197 is_frozen()? " [frozen]": "");
1198 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1199 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off());
1200 if (PrintRelocations) {
1201 RelocIterator iter(this);
1202 iter.print();
1203 }
1204 }
1205
1206 void CodeBuffer::print() {
1207 if (this == NULL) {
1208 tty->print_cr("NULL CodeBuffer pointer");
1209 return;
1210 }
1211
1212 tty->print_cr("CodeBuffer:");
1213 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1214 // print each section
1215 CodeSection* cs = code_section(n);
1216 cs->print(code_section_name(n));
1217 }
1218 }
1219
1220 #endif // PRODUCT