1 /*
2 * Copyright (c) 1997, 2016, 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 "compiler/disassembler.hpp"
28 #include "gc/shared/gcLocker.hpp"
29 #include "oops/methodData.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/icache.hpp"
32 #include "utilities/copy.hpp"
33 #include "utilities/xmlstream.hpp"
34
35 // The structure of a CodeSection:
36 //
37 // _start -> +----------------+
38 // | machine code...|
39 // _end -> |----------------|
40 // | |
41 // | (empty) |
42 // | |
43 // | |
44 // +----------------+
45 // _limit -> | |
46 //
47 // _locs_start -> +----------------+
48 // |reloc records...|
49 // |----------------|
50 // _locs_end -> | |
51 // | |
52 // | (empty) |
53 // | |
54 // | |
55 // +----------------+
56 // _locs_limit -> | |
57 // The _end (resp. _limit) pointer refers to the first
58 // unused (resp. unallocated) byte.
59
60 // The structure of the CodeBuffer while code is being accumulated:
61 //
62 // _total_start -> \
63 // _insts._start -> +----------------+
64 // | |
65 // | Code |
66 // | |
67 // _stubs._start -> |----------------|
68 // | |
69 // | Stubs | (also handlers for deopt/exception)
70 // | |
71 // _consts._start -> |----------------|
72 // | |
73 // | Constants |
74 // | |
75 // +----------------+
76 // + _total_size -> | |
77 //
78 // When the code and relocations are copied to the code cache,
79 // the empty parts of each section are removed, and everything
80 // is copied into contiguous locations.
81
82 typedef CodeBuffer::csize_t csize_t; // file-local definition
83
84 // External buffer, in a predefined CodeBlob.
85 // Important: The code_start must be taken exactly, and not realigned.
86 CodeBuffer::CodeBuffer(CodeBlob* blob) {
87 initialize_misc("static buffer");
88 initialize(blob->content_begin(), blob->content_size());
89 verify_section_allocation();
90 }
91
92 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
93 // Compute maximal alignment.
94 int align = _insts.alignment();
95 // Always allow for empty slop around each section.
96 int slop = (int) CodeSection::end_slop();
97
98 assert(blob() == NULL, "only once");
99 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1)));
100 if (blob() == NULL) {
101 // The assembler constructor will throw a fatal on an empty CodeBuffer.
102 return; // caller must test this
103 }
104
105 // Set up various pointers into the blob.
106 initialize(_total_start, _total_size);
107
108 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
109
110 pd_initialize();
111
112 if (locs_size != 0) {
113 _insts.initialize_locs(locs_size / sizeof(relocInfo));
114 }
115
116 verify_section_allocation();
117 }
118
119
120 CodeBuffer::~CodeBuffer() {
121 verify_section_allocation();
122
123 // If we allocate our code buffer from the CodeCache
124 // via a BufferBlob, and it's not permanent, then
125 // free the BufferBlob.
126 // The rest of the memory will be freed when the ResourceObj
127 // is released.
128 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) {
129 // Previous incarnations of this buffer are held live, so that internal
130 // addresses constructed before expansions will not be confused.
131 cb->free_blob();
132 }
133
134 // free any overflow storage
135 delete _overflow_arena;
136
137 // Claim is that stack allocation ensures resources are cleaned up.
138 // This is resource clean up, let's hope that all were properly copied out.
139 free_strings();
140
141 #ifdef ASSERT
142 // Save allocation type to execute assert in ~ResourceObj()
143 // which is called after this destructor.
144 assert(_default_oop_recorder.allocated_on_stack(), "should be embedded object");
145 ResourceObj::allocation_type at = _default_oop_recorder.get_allocation_type();
146 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue);
147 ResourceObj::set_allocation_type((address)(&_default_oop_recorder), at);
148 #endif
149 }
150
151 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
152 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
153 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen
154 _oop_recorder = r;
155 }
156
157 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
158 assert(cs != &_insts, "insts is the memory provider, not the consumer");
159 csize_t slop = CodeSection::end_slop(); // margin between sections
160 int align = cs->alignment();
161 assert(is_power_of_2(align), "sanity");
162 address start = _insts._start;
163 address limit = _insts._limit;
164 address middle = limit - size;
165 middle -= (intptr_t)middle & (align-1); // align the division point downward
166 guarantee(middle - slop > start, "need enough space to divide up");
167 _insts._limit = middle - slop; // subtract desired space, plus slop
168 cs->initialize(middle, limit - middle);
169 assert(cs->start() == middle, "sanity");
170 assert(cs->limit() == limit, "sanity");
171 // give it some relocations to start with, if the main section has them
172 if (_insts.has_locs()) cs->initialize_locs(1);
173 }
174
175 void CodeBuffer::freeze_section(CodeSection* cs) {
176 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1);
177 csize_t frozen_size = cs->size();
178 if (next_cs != NULL) {
179 frozen_size = next_cs->align_at_start(frozen_size);
180 }
181 address old_limit = cs->limit();
182 address new_limit = cs->start() + frozen_size;
183 relocInfo* old_locs_limit = cs->locs_limit();
184 relocInfo* new_locs_limit = cs->locs_end();
185 // Patch the limits.
186 cs->_limit = new_limit;
187 cs->_locs_limit = new_locs_limit;
188 cs->_frozen = true;
189 if (!next_cs->is_allocated() && !next_cs->is_frozen()) {
190 // Give remaining buffer space to the following section.
191 next_cs->initialize(new_limit, old_limit - new_limit);
192 next_cs->initialize_shared_locs(new_locs_limit,
193 old_locs_limit - new_locs_limit);
194 }
195 }
196
197 void CodeBuffer::set_blob(BufferBlob* blob) {
198 _blob = blob;
199 if (blob != NULL) {
200 address start = blob->content_begin();
201 address end = blob->content_end();
202 // Round up the starting address.
203 int align = _insts.alignment();
204 start += (-(intptr_t)start) & (align-1);
205 _total_start = start;
206 _total_size = end - start;
207 } else {
208 #ifdef ASSERT
209 // Clean out dangling pointers.
210 _total_start = badAddress;
211 _consts._start = _consts._end = badAddress;
212 _insts._start = _insts._end = badAddress;
213 _stubs._start = _stubs._end = badAddress;
214 #endif //ASSERT
215 }
216 }
217
218 void CodeBuffer::free_blob() {
219 if (_blob != NULL) {
220 BufferBlob::free(_blob);
221 set_blob(NULL);
222 }
223 }
224
225 const char* CodeBuffer::code_section_name(int n) {
226 #ifdef PRODUCT
227 return NULL;
228 #else //PRODUCT
229 switch (n) {
230 case SECT_CONSTS: return "consts";
231 case SECT_INSTS: return "insts";
232 case SECT_STUBS: return "stubs";
233 default: return NULL;
234 }
235 #endif //PRODUCT
236 }
237
238 int CodeBuffer::section_index_of(address addr) const {
239 for (int n = 0; n < (int)SECT_LIMIT; n++) {
240 const CodeSection* cs = code_section(n);
241 if (cs->allocates(addr)) return n;
242 }
243 return SECT_NONE;
244 }
245
246 int CodeBuffer::locator(address addr) const {
247 for (int n = 0; n < (int)SECT_LIMIT; n++) {
248 const CodeSection* cs = code_section(n);
249 if (cs->allocates(addr)) {
250 return locator(addr - cs->start(), n);
251 }
252 }
253 return -1;
254 }
255
256 address CodeBuffer::locator_address(int locator) const {
257 if (locator < 0) return NULL;
258 address start = code_section(locator_sect(locator))->start();
259 return start + locator_pos(locator);
260 }
261
262 bool CodeBuffer::is_backward_branch(Label& L) {
263 return L.is_bound() && insts_end() <= locator_address(L.loc());
264 }
265
266 address CodeBuffer::decode_begin() {
267 address begin = _insts.start();
268 if (_decode_begin != NULL && _decode_begin > begin)
269 begin = _decode_begin;
270 return begin;
271 }
272
273
274 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
275 if (_overflow_arena == NULL) {
276 _overflow_arena = new (mtCode) Arena(mtCode);
277 }
278 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
279 }
280
281
282 // Helper function for managing labels and their target addresses.
283 // Returns a sensible address, and if it is not the label's final
284 // address, notes the dependency (at 'branch_pc') on the label.
285 address CodeSection::target(Label& L, address branch_pc) {
286 if (L.is_bound()) {
287 int loc = L.loc();
288 if (index() == CodeBuffer::locator_sect(loc)) {
289 return start() + CodeBuffer::locator_pos(loc);
290 } else {
291 return outer()->locator_address(loc);
292 }
293 } else {
294 assert(allocates2(branch_pc), "sanity");
295 address base = start();
296 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
297 L.add_patch_at(outer(), patch_loc);
298
299 // Need to return a pc, doesn't matter what it is since it will be
300 // replaced during resolution later.
301 // Don't return NULL or badAddress, since branches shouldn't overflow.
302 // Don't return base either because that could overflow displacements
303 // for shorter branches. It will get checked when bound.
304 return branch_pc;
305 }
306 }
307
308 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) {
309 RelocationHolder rh;
310 switch (rtype) {
311 case relocInfo::none: return;
312 case relocInfo::opt_virtual_call_type: {
313 rh = opt_virtual_call_Relocation::spec(method_index);
314 break;
315 }
316 case relocInfo::static_call_type: {
317 rh = static_call_Relocation::spec(method_index);
318 break;
319 }
320 case relocInfo::virtual_call_type: {
321 assert(method_index == 0, "resolved method overriding is not supported");
322 rh = Relocation::spec_simple(rtype);
323 break;
324 }
325 default: {
326 rh = Relocation::spec_simple(rtype);
327 break;
328 }
329 }
330 relocate(at, rh, format);
331 }
332
333 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
334 // Do not relocate in scratch buffers.
335 if (scratch_emit()) { return; }
336 Relocation* reloc = spec.reloc();
337 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
338 if (rtype == relocInfo::none) return;
339
340 // The assertion below has been adjusted, to also work for
341 // relocation for fixup. Sometimes we want to put relocation
342 // information for the next instruction, since it will be patched
343 // with a call.
344 assert(start() <= at && at <= end()+1,
345 "cannot relocate data outside code boundaries");
346
347 if (!has_locs()) {
348 // no space for relocation information provided => code cannot be
349 // relocated. Make sure that relocate is only called with rtypes
350 // that can be ignored for this kind of code.
351 assert(rtype == relocInfo::none ||
352 rtype == relocInfo::runtime_call_type ||
353 rtype == relocInfo::internal_word_type||
354 rtype == relocInfo::section_word_type ||
355 rtype == relocInfo::external_word_type,
356 "code needs relocation information");
357 // leave behind an indication that we attempted a relocation
358 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
359 return;
360 }
361
362 // Advance the point, noting the offset we'll have to record.
363 csize_t offset = at - locs_point();
364 set_locs_point(at);
365
366 // Test for a couple of overflow conditions; maybe expand the buffer.
367 relocInfo* end = locs_end();
368 relocInfo* req = end + relocInfo::length_limit;
369 // Check for (potential) overflow
370 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
371 req += (uint)offset / (uint)relocInfo::offset_limit();
372 if (req >= locs_limit()) {
373 // Allocate or reallocate.
374 expand_locs(locs_count() + (req - end));
375 // reload pointer
376 end = locs_end();
377 }
378 }
379
380 // If the offset is giant, emit filler relocs, of type 'none', but
381 // each carrying the largest possible offset, to advance the locs_point.
382 while (offset >= relocInfo::offset_limit()) {
383 assert(end < locs_limit(), "adjust previous paragraph of code");
384 *end++ = filler_relocInfo();
385 offset -= filler_relocInfo().addr_offset();
386 }
387
388 // If it's a simple reloc with no data, we'll just write (rtype | offset).
389 (*end) = relocInfo(rtype, offset, format);
390
391 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
392 end->initialize(this, reloc);
393 }
394
395 void CodeSection::initialize_locs(int locs_capacity) {
396 assert(_locs_start == NULL, "only one locs init step, please");
397 // Apply a priori lower limits to relocation size:
398 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
399 if (locs_capacity < min_locs) locs_capacity = min_locs;
400 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
401 _locs_start = locs_start;
402 _locs_end = locs_start;
403 _locs_limit = locs_start + locs_capacity;
404 _locs_own = true;
405 }
406
407 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
408 assert(_locs_start == NULL, "do this before locs are allocated");
409 // Internal invariant: locs buf must be fully aligned.
410 // See copy_relocations_to() below.
411 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
412 ++buf; --length;
413 }
414 if (length > 0) {
415 _locs_start = buf;
416 _locs_end = buf;
417 _locs_limit = buf + length;
418 _locs_own = false;
419 }
420 }
421
422 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
423 int lcount = source_cs->locs_count();
424 if (lcount != 0) {
425 initialize_shared_locs(source_cs->locs_start(), lcount);
426 _locs_end = _locs_limit = _locs_start + lcount;
427 assert(is_allocated(), "must have copied code already");
428 set_locs_point(start() + source_cs->locs_point_off());
429 }
430 assert(this->locs_count() == source_cs->locs_count(), "sanity");
431 }
432
433 void CodeSection::expand_locs(int new_capacity) {
434 if (_locs_start == NULL) {
435 initialize_locs(new_capacity);
436 return;
437 } else {
438 int old_count = locs_count();
439 int old_capacity = locs_capacity();
440 if (new_capacity < old_capacity * 2)
441 new_capacity = old_capacity * 2;
442 relocInfo* locs_start;
443 if (_locs_own) {
444 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
445 } else {
446 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
447 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
448 _locs_own = true;
449 }
450 _locs_start = locs_start;
451 _locs_end = locs_start + old_count;
452 _locs_limit = locs_start + new_capacity;
453 }
454 }
455
456
457 /// Support for emitting the code to its final location.
458 /// The pattern is the same for all functions.
459 /// We iterate over all the sections, padding each to alignment.
460
461 csize_t CodeBuffer::total_content_size() const {
462 csize_t size_so_far = 0;
463 for (int n = 0; n < (int)SECT_LIMIT; n++) {
464 const CodeSection* cs = code_section(n);
465 if (cs->is_empty()) continue; // skip trivial section
466 size_so_far = cs->align_at_start(size_so_far);
467 size_so_far += cs->size();
468 }
469 return size_so_far;
470 }
471
472 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
473 address buf = dest->_total_start;
474 csize_t buf_offset = 0;
475 assert(dest->_total_size >= total_content_size(), "must be big enough");
476
477 {
478 // not sure why this is here, but why not...
479 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
480 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
481 }
482
483 const CodeSection* prev_cs = NULL;
484 CodeSection* prev_dest_cs = NULL;
485
486 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
487 // figure compact layout of each section
488 const CodeSection* cs = code_section(n);
489 csize_t csize = cs->size();
490
491 CodeSection* dest_cs = dest->code_section(n);
492 if (!cs->is_empty()) {
493 // Compute initial padding; assign it to the previous non-empty guy.
494 // Cf. figure_expanded_capacities.
495 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
496 if (padding != 0) {
497 buf_offset += padding;
498 assert(prev_dest_cs != NULL, "sanity");
499 prev_dest_cs->_limit += padding;
500 }
501 #ifdef ASSERT
502 if (prev_cs != NULL && prev_cs->is_frozen() && n < (SECT_LIMIT - 1)) {
503 // Make sure the ends still match up.
504 // This is important because a branch in a frozen section
505 // might target code in a following section, via a Label,
506 // and without a relocation record. See Label::patch_instructions.
507 address dest_start = buf+buf_offset;
508 csize_t start2start = cs->start() - prev_cs->start();
509 csize_t dest_start2start = dest_start - prev_dest_cs->start();
510 assert(start2start == dest_start2start, "cannot stretch frozen sect");
511 }
512 #endif //ASSERT
513 prev_dest_cs = dest_cs;
514 prev_cs = cs;
515 }
516
517 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert
518 dest_cs->initialize(buf+buf_offset, csize);
519 dest_cs->set_end(buf+buf_offset+csize);
520 assert(dest_cs->is_allocated(), "must always be allocated");
521 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
522
523 buf_offset += csize;
524 }
525
526 // Done calculating sections; did it come out to the right end?
527 assert(buf_offset == total_content_size(), "sanity");
528 dest->verify_section_allocation();
529 }
530
531 // Append an oop reference that keeps the class alive.
532 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) {
533 oop cl = k->klass_holder();
534 if (cl != NULL && !oops->contains(cl)) {
535 oops->append(cl);
536 }
537 }
538
539 void CodeBuffer::finalize_oop_references(const methodHandle& mh) {
540 NoSafepointVerifier nsv;
541
542 GrowableArray<oop> oops;
543
544 // Make sure that immediate metadata records something in the OopRecorder
545 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
546 // pull code out of each section
547 CodeSection* cs = code_section(n);
548 if (cs->is_empty()) continue; // skip trivial section
549 RelocIterator iter(cs);
550 while (iter.next()) {
551 if (iter.type() == relocInfo::metadata_type) {
552 metadata_Relocation* md = iter.metadata_reloc();
553 if (md->metadata_is_immediate()) {
554 Metadata* m = md->metadata_value();
555 if (oop_recorder()->is_real(m)) {
556 if (m->is_methodData()) {
557 m = ((MethodData*)m)->method();
558 }
559 if (m->is_method()) {
560 m = ((Method*)m)->method_holder();
561 }
562 if (m->is_klass()) {
563 append_oop_references(&oops, (Klass*)m);
564 } else {
565 // XXX This will currently occur for MDO which don't
566 // have a backpointer. This has to be fixed later.
567 m->print();
568 ShouldNotReachHere();
569 }
570 }
571 }
572 }
573 }
574 }
575
576 if (!oop_recorder()->is_unused()) {
577 for (int i = 0; i < oop_recorder()->metadata_count(); i++) {
578 Metadata* m = oop_recorder()->metadata_at(i);
579 if (oop_recorder()->is_real(m)) {
580 if (m->is_methodData()) {
581 m = ((MethodData*)m)->method();
582 }
583 if (m->is_method()) {
584 m = ((Method*)m)->method_holder();
585 }
586 if (m->is_klass()) {
587 append_oop_references(&oops, (Klass*)m);
588 } else {
589 m->print();
590 ShouldNotReachHere();
591 }
592 }
593 }
594
595 }
596
597 // Add the class loader of Method* for the nmethod itself
598 append_oop_references(&oops, mh->method_holder());
599
600 // Add any oops that we've found
601 Thread* thread = Thread::current();
602 for (int i = 0; i < oops.length(); i++) {
603 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i)));
604 }
605 }
606
607
608
609 csize_t CodeBuffer::total_offset_of(const CodeSection* cs) const {
610 csize_t size_so_far = 0;
611 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
612 const CodeSection* cur_cs = code_section(n);
613 if (!cur_cs->is_empty()) {
614 size_so_far = cur_cs->align_at_start(size_so_far);
615 }
616 if (cur_cs->index() == cs->index()) {
617 return size_so_far;
618 }
619 size_so_far += cur_cs->size();
620 }
621 ShouldNotReachHere();
622 return -1;
623 }
624
625 csize_t CodeBuffer::total_relocation_size() const {
626 csize_t lsize = copy_relocations_to(NULL); // dry run only
627 csize_t csize = total_content_size();
628 csize_t total = RelocIterator::locs_and_index_size(csize, lsize);
629 return (csize_t) align_size_up(total, HeapWordSize);
630 }
631
632 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const {
633 csize_t buf_offset = 0;
634 csize_t code_end_so_far = 0;
635 csize_t code_point_so_far = 0;
636
637 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
638 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
639
640 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
641 if (only_inst && (n != (int)SECT_INSTS)) {
642 // Need only relocation info for code.
643 continue;
644 }
645 // pull relocs out of each section
646 const CodeSection* cs = code_section(n);
647 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
648 if (cs->is_empty()) continue; // skip trivial section
649 relocInfo* lstart = cs->locs_start();
650 relocInfo* lend = cs->locs_end();
651 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
652 csize_t csize = cs->size();
653 code_end_so_far = cs->align_at_start(code_end_so_far);
654
655 if (lsize > 0) {
656 // Figure out how to advance the combined relocation point
657 // first to the beginning of this section.
658 // We'll insert one or more filler relocs to span that gap.
659 // (Don't bother to improve this by editing the first reloc's offset.)
660 csize_t new_code_point = code_end_so_far;
661 for (csize_t jump;
662 code_point_so_far < new_code_point;
663 code_point_so_far += jump) {
664 jump = new_code_point - code_point_so_far;
665 relocInfo filler = filler_relocInfo();
666 if (jump >= filler.addr_offset()) {
667 jump = filler.addr_offset();
668 } else { // else shrink the filler to fit
669 filler = relocInfo(relocInfo::none, jump);
670 }
671 if (buf != NULL) {
672 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
673 *(relocInfo*)(buf+buf_offset) = filler;
674 }
675 buf_offset += sizeof(filler);
676 }
677
678 // Update code point and end to skip past this section:
679 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
680 assert(code_point_so_far <= last_code_point, "sanity");
681 code_point_so_far = last_code_point; // advance past this guy's relocs
682 }
683 code_end_so_far += csize; // advance past this guy's instructions too
684
685 // Done with filler; emit the real relocations:
686 if (buf != NULL && lsize != 0) {
687 assert(buf_offset + lsize <= buf_limit, "target in bounds");
688 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
689 if (buf_offset % HeapWordSize == 0) {
690 // Use wordwise copies if possible:
691 Copy::disjoint_words((HeapWord*)lstart,
692 (HeapWord*)(buf+buf_offset),
693 (lsize + HeapWordSize-1) / HeapWordSize);
694 } else {
695 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
696 }
697 }
698 buf_offset += lsize;
699 }
700
701 // Align end of relocation info in target.
702 while (buf_offset % HeapWordSize != 0) {
703 if (buf != NULL) {
704 relocInfo padding = relocInfo(relocInfo::none, 0);
705 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
706 *(relocInfo*)(buf+buf_offset) = padding;
707 }
708 buf_offset += sizeof(relocInfo);
709 }
710
711 assert(only_inst || code_end_so_far == total_content_size(), "sanity");
712
713 return buf_offset;
714 }
715
716 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
717 address buf = NULL;
718 csize_t buf_offset = 0;
719 csize_t buf_limit = 0;
720
721 if (dest != NULL) {
722 buf = (address)dest->relocation_begin();
723 buf_limit = (address)dest->relocation_end() - buf;
724 }
725 // if dest == NULL, this is just the sizing pass
726 //
727 buf_offset = copy_relocations_to(buf, buf_limit, false);
728
729 // Account for index:
730 if (buf != NULL) {
731 RelocIterator::create_index(dest->relocation_begin(),
732 buf_offset / sizeof(relocInfo),
733 dest->relocation_end());
734 }
735
736 return buf_offset;
737 }
738
739 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
740 #ifndef PRODUCT
741 if (PrintNMethods && (WizardMode || Verbose)) {
742 tty->print("done with CodeBuffer:");
743 ((CodeBuffer*)this)->print();
744 }
745 #endif //PRODUCT
746
747 CodeBuffer dest(dest_blob);
748 assert(dest_blob->content_size() >= total_content_size(), "good sizing");
749 this->compute_final_layout(&dest);
750
751 // Set beginning of constant table before relocating.
752 dest_blob->set_ctable_begin(dest.consts()->start());
753
754 relocate_code_to(&dest);
755
756 // transfer strings and comments from buffer to blob
757 dest_blob->set_strings(_code_strings);
758
759 // Done moving code bytes; were they the right size?
760 assert(round_to(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity");
761
762 // Flush generated code
763 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size());
764 }
765
766 // Move all my code into another code buffer. Consult applicable
767 // relocs to repair embedded addresses. The layout in the destination
768 // CodeBuffer is different to the source CodeBuffer: the destination
769 // CodeBuffer gets the final layout (consts, insts, stubs in order of
770 // ascending address).
771 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
772 address dest_end = dest->_total_start + dest->_total_size;
773 address dest_filled = NULL;
774 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
775 // pull code out of each section
776 const CodeSection* cs = code_section(n);
777 if (cs->is_empty()) continue; // skip trivial section
778 CodeSection* dest_cs = dest->code_section(n);
779 assert(cs->size() == dest_cs->size(), "sanity");
780 csize_t usize = dest_cs->size();
781 csize_t wsize = align_size_up(usize, HeapWordSize);
782 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
783 // Copy the code as aligned machine words.
784 // This may also include an uninitialized partial word at the end.
785 Copy::disjoint_words((HeapWord*)cs->start(),
786 (HeapWord*)dest_cs->start(),
787 wsize / HeapWordSize);
788
789 if (dest->blob() == NULL) {
790 // Destination is a final resting place, not just another buffer.
791 // Normalize uninitialized bytes in the final padding.
792 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
793 Assembler::code_fill_byte());
794 }
795 // Keep track of the highest filled address
796 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining());
797
798 assert(cs->locs_start() != (relocInfo*)badAddress,
799 "this section carries no reloc storage, but reloc was attempted");
800
801 // Make the new code copy use the old copy's relocations:
802 dest_cs->initialize_locs_from(cs);
803 }
804
805 // Do relocation after all sections are copied.
806 // This is necessary if the code uses constants in stubs, which are
807 // relocated when the corresponding instruction in the code (e.g., a
808 // call) is relocated. Stubs are placed behind the main code
809 // section, so that section has to be copied before relocating.
810 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
811 // pull code out of each section
812 const CodeSection* cs = code_section(n);
813 if (cs->is_empty()) continue; // skip trivial section
814 CodeSection* dest_cs = dest->code_section(n);
815 { // Repair the pc relative information in the code after the move
816 RelocIterator iter(dest_cs);
817 while (iter.next()) {
818 iter.reloc()->fix_relocation_after_move(this, dest);
819 }
820 }
821 }
822
823 if (dest->blob() == NULL && dest_filled != NULL) {
824 // Destination is a final resting place, not just another buffer.
825 // Normalize uninitialized bytes in the final padding.
826 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,
827 Assembler::code_fill_byte());
828
829 }
830 }
831
832 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
833 csize_t amount,
834 csize_t* new_capacity) {
835 csize_t new_total_cap = 0;
836
837 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
838 const CodeSection* sect = code_section(n);
839
840 if (!sect->is_empty()) {
841 // Compute initial padding; assign it to the previous section,
842 // even if it's empty (e.g. consts section can be empty).
843 // Cf. compute_final_layout
844 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
845 if (padding != 0) {
846 new_total_cap += padding;
847 assert(n - 1 >= SECT_FIRST, "sanity");
848 new_capacity[n - 1] += padding;
849 }
850 }
851
852 csize_t exp = sect->size(); // 100% increase
853 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
854 if (sect == which_cs) {
855 if (exp < amount) exp = amount;
856 if (StressCodeBuffers) exp = amount; // expand only slightly
857 } else if (n == SECT_INSTS) {
858 // scale down inst increases to a more modest 25%
859 exp = 4*K + ((exp - 4*K) >> 2);
860 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
861 } else if (sect->is_empty()) {
862 // do not grow an empty secondary section
863 exp = 0;
864 }
865 // Allow for inter-section slop:
866 exp += CodeSection::end_slop();
867 csize_t new_cap = sect->size() + exp;
868 if (new_cap < sect->capacity()) {
869 // No need to expand after all.
870 new_cap = sect->capacity();
871 }
872 new_capacity[n] = new_cap;
873 new_total_cap += new_cap;
874 }
875
876 return new_total_cap;
877 }
878
879 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
880 #ifndef PRODUCT
881 if (PrintNMethods && (WizardMode || Verbose)) {
882 tty->print("expanding CodeBuffer:");
883 this->print();
884 }
885
886 if (StressCodeBuffers && blob() != NULL) {
887 static int expand_count = 0;
888 if (expand_count >= 0) expand_count += 1;
889 if (expand_count > 100 && is_power_of_2(expand_count)) {
890 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
891 // simulate an occasional allocation failure:
892 free_blob();
893 }
894 }
895 #endif //PRODUCT
896
897 // Resizing must be allowed
898 {
899 if (blob() == NULL) return; // caller must check for blob == NULL
900 for (int n = 0; n < (int)SECT_LIMIT; n++) {
901 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen");
902 }
903 }
904
905 // Figure new capacity for each section.
906 csize_t new_capacity[SECT_LIMIT];
907 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT);
908 csize_t new_total_cap
909 = figure_expanded_capacities(which_cs, amount, new_capacity);
910
911 // Create a new (temporary) code buffer to hold all the new data
912 CodeBuffer cb(name(), new_total_cap, 0);
913 if (cb.blob() == NULL) {
914 // Failed to allocate in code cache.
915 free_blob();
916 return;
917 }
918
919 // Create an old code buffer to remember which addresses used to go where.
920 // This will be useful when we do final assembly into the code cache,
921 // because we will need to know how to warp any internal address that
922 // has been created at any time in this CodeBuffer's past.
923 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
924 bxp->take_over_code_from(this); // remember the old undersized blob
925 DEBUG_ONLY(this->_blob = NULL); // silence a later assert
926 bxp->_before_expand = this->_before_expand;
927 this->_before_expand = bxp;
928
929 // Give each section its required (expanded) capacity.
930 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) {
931 CodeSection* cb_sect = cb.code_section(n);
932 CodeSection* this_sect = code_section(n);
933 if (new_capacity[n] == 0) continue; // already nulled out
934 if (n != SECT_INSTS) {
935 cb.initialize_section_size(cb_sect, new_capacity[n]);
936 }
937 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
938 address cb_start = cb_sect->start();
939 cb_sect->set_end(cb_start + this_sect->size());
940 if (this_sect->mark() == NULL) {
941 cb_sect->clear_mark();
942 } else {
943 cb_sect->set_mark(cb_start + this_sect->mark_off());
944 }
945 }
946
947 // Needs to be initialized when calling fix_relocation_after_move.
948 cb.blob()->set_ctable_begin(cb.consts()->start());
949
950 // Move all the code and relocations to the new blob:
951 relocate_code_to(&cb);
952
953 // Copy the temporary code buffer into the current code buffer.
954 // Basically, do {*this = cb}, except for some control information.
955 this->take_over_code_from(&cb);
956 cb.set_blob(NULL);
957
958 // Zap the old code buffer contents, to avoid mistakenly using them.
959 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
960 badCodeHeapFreeVal));
961
962 _decode_begin = NULL; // sanity
963
964 // Make certain that the new sections are all snugly inside the new blob.
965 verify_section_allocation();
966
967 #ifndef PRODUCT
968 if (PrintNMethods && (WizardMode || Verbose)) {
969 tty->print("expanded CodeBuffer:");
970 this->print();
971 }
972 #endif //PRODUCT
973 }
974
975 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
976 // Must already have disposed of the old blob somehow.
977 assert(blob() == NULL, "must be empty");
978 // Take the new blob away from cb.
979 set_blob(cb->blob());
980 // Take over all the section pointers.
981 for (int n = 0; n < (int)SECT_LIMIT; n++) {
982 CodeSection* cb_sect = cb->code_section(n);
983 CodeSection* this_sect = code_section(n);
984 this_sect->take_over_code_from(cb_sect);
985 }
986 _overflow_arena = cb->_overflow_arena;
987 // Make sure the old cb won't try to use it or free it.
988 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
989 }
990
991 void CodeBuffer::verify_section_allocation() {
992 address tstart = _total_start;
993 if (tstart == badAddress) return; // smashed by set_blob(NULL)
994 address tend = tstart + _total_size;
995 if (_blob != NULL) {
996
997 guarantee(tstart >= _blob->content_begin(), "sanity");
998 guarantee(tend <= _blob->content_end(), "sanity");
999 }
1000 // Verify disjointness.
1001 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
1002 CodeSection* sect = code_section(n);
1003 if (!sect->is_allocated() || sect->is_empty()) continue;
1004 guarantee((intptr_t)sect->start() % sect->alignment() == 0
1005 || sect->is_empty() || _blob == NULL,
1006 "start is aligned");
1007 for (int m = (int) SECT_FIRST; m < (int) SECT_LIMIT; m++) {
1008 CodeSection* other = code_section(m);
1009 if (!other->is_allocated() || other == sect) continue;
1010 guarantee(!other->contains(sect->start() ), "sanity");
1011 // limit is an exclusive address and can be the start of another
1012 // section.
1013 guarantee(!other->contains(sect->limit() - 1), "sanity");
1014 }
1015 guarantee(sect->end() <= tend, "sanity");
1016 guarantee(sect->end() <= sect->limit(), "sanity");
1017 }
1018 }
1019
1020 void CodeBuffer::log_section_sizes(const char* name) {
1021 if (xtty != NULL) {
1022 ttyLocker ttyl;
1023 // log info about buffer usage
1024 xtty->print_cr("<blob name='%s' size='%d'>", name, _total_size);
1025 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
1026 CodeSection* sect = code_section(n);
1027 if (!sect->is_allocated() || sect->is_empty()) continue;
1028 xtty->print_cr("<sect index='%d' size='" SIZE_FORMAT "' free='" SIZE_FORMAT "'/>",
1029 n, sect->limit() - sect->start(), sect->limit() - sect->end());
1030 }
1031 xtty->print_cr("</blob>");
1032 }
1033 }
1034
1035 #ifndef PRODUCT
1036
1037 void CodeSection::dump() {
1038 address ptr = start();
1039 for (csize_t step; ptr < end(); ptr += step) {
1040 step = end() - ptr;
1041 if (step > jintSize * 4) step = jintSize * 4;
1042 tty->print(INTPTR_FORMAT ": ", p2i(ptr));
1043 while (step > 0) {
1044 tty->print(" " PTR32_FORMAT, *(jint*)ptr);
1045 ptr += jintSize;
1046 }
1047 tty->cr();
1048 }
1049 }
1050
1051
1052 void CodeSection::decode() {
1053 Disassembler::decode(start(), end());
1054 }
1055
1056
1057 void CodeBuffer::block_comment(intptr_t offset, const char * comment) {
1058 _code_strings.add_comment(offset, comment);
1059 }
1060
1061 const char* CodeBuffer::code_string(const char* str) {
1062 return _code_strings.add_string(str);
1063 }
1064
1065 class CodeString: public CHeapObj<mtCode> {
1066 private:
1067 friend class CodeStrings;
1068 const char * _string;
1069 CodeString* _next;
1070 intptr_t _offset;
1071
1072 ~CodeString() {
1073 assert(_next == NULL, "wrong interface for freeing list");
1074 os::free((void*)_string);
1075 }
1076
1077 bool is_comment() const { return _offset >= 0; }
1078
1079 public:
1080 CodeString(const char * string, intptr_t offset = -1)
1081 : _next(NULL), _offset(offset) {
1082 _string = os::strdup(string, mtCode);
1083 }
1084
1085 const char * string() const { return _string; }
1086 intptr_t offset() const { assert(_offset >= 0, "offset for non comment?"); return _offset; }
1087 CodeString* next() const { return _next; }
1088
1089 void set_next(CodeString* next) { _next = next; }
1090
1091 CodeString* first_comment() {
1092 if (is_comment()) {
1093 return this;
1094 } else {
1095 return next_comment();
1096 }
1097 }
1098 CodeString* next_comment() const {
1099 CodeString* s = _next;
1100 while (s != NULL && !s->is_comment()) {
1101 s = s->_next;
1102 }
1103 return s;
1104 }
1105 };
1106
1107 CodeString* CodeStrings::find(intptr_t offset) const {
1108 CodeString* a = _strings->first_comment();
1109 while (a != NULL && a->offset() != offset) {
1110 a = a->next_comment();
1111 }
1112 return a;
1113 }
1114
1115 // Convenience for add_comment.
1116 CodeString* CodeStrings::find_last(intptr_t offset) const {
1117 CodeString* a = find(offset);
1118 if (a != NULL) {
1119 CodeString* c = NULL;
1120 while (((c = a->next_comment()) != NULL) && (c->offset() == offset)) {
1121 a = c;
1122 }
1123 }
1124 return a;
1125 }
1126
1127 void CodeStrings::add_comment(intptr_t offset, const char * comment) {
1128 check_valid();
1129 CodeString* c = new CodeString(comment, offset);
1130 CodeString* inspos = (_strings == NULL) ? NULL : find_last(offset);
1131
1132 if (inspos) {
1133 // insert after already existing comments with same offset
1134 c->set_next(inspos->next());
1135 inspos->set_next(c);
1136 } else {
1137 // no comments with such offset, yet. Insert before anything else.
1138 c->set_next(_strings);
1139 _strings = c;
1140 }
1141 }
1142
1143 void CodeStrings::assign(CodeStrings& other) {
1144 other.check_valid();
1145 assert(is_null(), "Cannot assign onto non-empty CodeStrings");
1146 _strings = other._strings;
1147 #ifdef ASSERT
1148 _defunct = false;
1149 #endif
1150 other.set_null_and_invalidate();
1151 }
1152
1153 // Deep copy of CodeStrings for consistent memory management.
1154 // Only used for actual disassembly so this is cheaper than reference counting
1155 // for the "normal" fastdebug case.
1156 void CodeStrings::copy(CodeStrings& other) {
1157 other.check_valid();
1158 check_valid();
1159 assert(is_null(), "Cannot copy onto non-empty CodeStrings");
1160 CodeString* n = other._strings;
1161 CodeString** ps = &_strings;
1162 while (n != NULL) {
1163 *ps = new CodeString(n->string(),n->offset());
1164 ps = &((*ps)->_next);
1165 n = n->next();
1166 }
1167 }
1168
1169 const char* CodeStrings::_prefix = " ;; "; // default: can be changed via set_prefix
1170
1171 void CodeStrings::print_block_comment(outputStream* stream, intptr_t offset) const {
1172 check_valid();
1173 if (_strings != NULL) {
1174 CodeString* c = find(offset);
1175 while (c && c->offset() == offset) {
1176 stream->bol();
1177 stream->print("%s", _prefix);
1178 // Don't interpret as format strings since it could contain %
1179 stream->print_raw_cr(c->string());
1180 c = c->next_comment();
1181 }
1182 }
1183 }
1184
1185 // Also sets isNull()
1186 void CodeStrings::free() {
1187 CodeString* n = _strings;
1188 while (n) {
1189 // unlink the node from the list saving a pointer to the next
1190 CodeString* p = n->next();
1191 n->set_next(NULL);
1192 delete n;
1193 n = p;
1194 }
1195 set_null_and_invalidate();
1196 }
1197
1198 const char* CodeStrings::add_string(const char * string) {
1199 check_valid();
1200 CodeString* s = new CodeString(string);
1201 s->set_next(_strings);
1202 _strings = s;
1203 assert(s->string() != NULL, "should have a string");
1204 return s->string();
1205 }
1206
1207 void CodeBuffer::decode() {
1208 ttyLocker ttyl;
1209 Disassembler::decode(decode_begin(), insts_end());
1210 _decode_begin = insts_end();
1211 }
1212
1213
1214 void CodeBuffer::skip_decode() {
1215 _decode_begin = insts_end();
1216 }
1217
1218
1219 void CodeBuffer::decode_all() {
1220 ttyLocker ttyl;
1221 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1222 // dump contents of each section
1223 CodeSection* cs = code_section(n);
1224 tty->print_cr("! %s:", code_section_name(n));
1225 if (cs != consts())
1226 cs->decode();
1227 else
1228 cs->dump();
1229 }
1230 }
1231
1232
1233 void CodeSection::print(const char* name) {
1234 csize_t locs_size = locs_end() - locs_start();
1235 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s",
1236 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity(),
1237 is_frozen()? " [frozen]": "");
1238 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1239 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off());
1240 if (PrintRelocations) {
1241 RelocIterator iter(this);
1242 iter.print();
1243 }
1244 }
1245
1246 void CodeBuffer::print() {
1247 if (this == NULL) {
1248 tty->print_cr("NULL CodeBuffer pointer");
1249 return;
1250 }
1251
1252 tty->print_cr("CodeBuffer:");
1253 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1254 // print each section
1255 CodeSection* cs = code_section(n);
1256 cs->print(code_section_name(n));
1257 }
1258 }
1259
1260 #endif // PRODUCT