1 /*
2 * Copyright (c) 1997, 2018, 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 "oops/methodData.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/icache.hpp"
31 #include "runtime/safepointVerifiers.hpp"
32 #include "utilities/align.hpp"
33 #include "utilities/copy.hpp"
34 #include "utilities/xmlstream.hpp"
35
36 // The structure of a CodeSection:
37 //
38 // _start -> +----------------+
39 // | machine code...|
40 // _end -> |----------------|
41 // | |
42 // | (empty) |
43 // | |
44 // | |
45 // +----------------+
46 // _limit -> | |
47 //
48 // _locs_start -> +----------------+
49 // |reloc records...|
50 // |----------------|
51 // _locs_end -> | |
52 // | |
53 // | (empty) |
54 // | |
55 // | |
56 // +----------------+
57 // _locs_limit -> | |
58 // The _end (resp. _limit) pointer refers to the first
59 // unused (resp. unallocated) byte.
60
61 // The structure of the CodeBuffer while code is being accumulated:
62 //
63 // _total_start -> \
64 // _insts._start -> +----------------+
65 // | |
66 // | Code |
67 // | |
68 // _stubs._start -> |----------------|
69 // | |
70 // | Stubs | (also handlers for deopt/exception)
71 // | |
72 // _consts._start -> |----------------|
73 // | |
74 // | Constants |
75 // | |
76 // +----------------+
77 // + _total_size -> | |
78 //
79 // When the code and relocations are copied to the code cache,
80 // the empty parts of each section are removed, and everything
81 // is copied into contiguous locations.
82
83 typedef CodeBuffer::csize_t csize_t; // file-local definition
84
85 // External buffer, in a predefined CodeBlob.
86 // Important: The code_start must be taken exactly, and not realigned.
87 CodeBuffer::CodeBuffer(CodeBlob* blob) {
88 initialize_misc("static buffer");
89 initialize(blob->content_begin(), blob->content_size());
90 verify_section_allocation();
91 }
92
93 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
94 // Compute maximal alignment.
95 int align = _insts.alignment();
96 // Always allow for empty slop around each section.
97 int slop = (int) CodeSection::end_slop();
98
99 assert(blob() == NULL, "only once");
100 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1)));
101 if (blob() == NULL) {
102 // The assembler constructor will throw a fatal on an empty CodeBuffer.
103 return; // caller must test this
104 }
105
106 // Set up various pointers into the blob.
107 initialize(_total_start, _total_size);
108
109 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
110
111 pd_initialize();
112
113 if (locs_size != 0) {
114 _insts.initialize_locs(locs_size / sizeof(relocInfo));
115 }
116
117 verify_section_allocation();
118 }
119
120
121 CodeBuffer::~CodeBuffer() {
122 verify_section_allocation();
123
124 // If we allocate our code buffer from the CodeCache
125 // via a BufferBlob, and it's not permanent, then
126 // free the BufferBlob.
127 // The rest of the memory will be freed when the ResourceObj
128 // is released.
129 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) {
130 // Previous incarnations of this buffer are held live, so that internal
131 // addresses constructed before expansions will not be confused.
132 cb->free_blob();
133 }
134
135 // free any overflow storage
136 delete _overflow_arena;
137
138 // Claim is that stack allocation ensures resources are cleaned up.
139 // This is resource clean up, let's hope that all were properly copied out.
140 free_strings();
141
142 #ifdef ASSERT
143 // Save allocation type to execute assert in ~ResourceObj()
144 // which is called after this destructor.
145 assert(_default_oop_recorder.allocated_on_stack(), "should be embedded object");
146 ResourceObj::allocation_type at = _default_oop_recorder.get_allocation_type();
147 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue);
148 ResourceObj::set_allocation_type((address)(&_default_oop_recorder), at);
149 #endif
150 }
151
152 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
153 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
154 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen
155 _oop_recorder = r;
156 }
157
158 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
159 assert(cs != &_insts, "insts is the memory provider, not the consumer");
160 csize_t slop = CodeSection::end_slop(); // margin between sections
161 int align = cs->alignment();
162 assert(is_power_of_2(align), "sanity");
163 address start = _insts._start;
164 address limit = _insts._limit;
165 address middle = limit - size;
166 middle -= (intptr_t)middle & (align-1); // align the division point downward
167 guarantee(middle - slop > start, "need enough space to divide up");
168 _insts._limit = middle - slop; // subtract desired space, plus slop
169 cs->initialize(middle, limit - middle);
170 assert(cs->start() == middle, "sanity");
171 assert(cs->limit() == limit, "sanity");
172 // give it some relocations to start with, if the main section has them
173 if (_insts.has_locs()) cs->initialize_locs(1);
174 }
175
176 void CodeBuffer::freeze_section(CodeSection* cs) {
177 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1);
178 csize_t frozen_size = cs->size();
179 if (next_cs != NULL) {
180 frozen_size = next_cs->align_at_start(frozen_size);
181 }
182 address old_limit = cs->limit();
183 address new_limit = cs->start() + frozen_size;
184 relocInfo* old_locs_limit = cs->locs_limit();
185 relocInfo* new_locs_limit = cs->locs_end();
186 // Patch the limits.
187 cs->_limit = new_limit;
188 cs->_locs_limit = new_locs_limit;
189 cs->_frozen = true;
190 if (next_cs != NULL && !next_cs->is_allocated() && !next_cs->is_frozen()) {
191 // Give remaining buffer space to the following section.
192 next_cs->initialize(new_limit, old_limit - new_limit);
193 next_cs->initialize_shared_locs(new_locs_limit,
194 old_locs_limit - new_locs_limit);
195 }
196 }
197
198 void CodeBuffer::set_blob(BufferBlob* blob) {
199 _blob = blob;
200 if (blob != NULL) {
201 address start = blob->content_begin();
202 address end = blob->content_end();
203 // Round up the starting address.
204 int align = _insts.alignment();
205 start += (-(intptr_t)start) & (align-1);
206 _total_start = start;
207 _total_size = end - start;
208 } else {
209 #ifdef ASSERT
210 // Clean out dangling pointers.
211 _total_start = badAddress;
212 _consts._start = _consts._end = badAddress;
213 _insts._start = _insts._end = badAddress;
214 _stubs._start = _stubs._end = badAddress;
215 #endif //ASSERT
216 }
217 }
218
219 void CodeBuffer::free_blob() {
220 if (_blob != NULL) {
221 BufferBlob::free(_blob);
222 set_blob(NULL);
223 }
224 }
225
226 const char* CodeBuffer::code_section_name(int n) {
227 #ifdef PRODUCT
228 return NULL;
229 #else //PRODUCT
230 switch (n) {
231 case SECT_CONSTS: return "consts";
232 case SECT_INSTS: return "insts";
233 case SECT_STUBS: return "stubs";
234 default: return NULL;
235 }
236 #endif //PRODUCT
237 }
238
239 int CodeBuffer::section_index_of(address addr) const {
240 for (int n = 0; n < (int)SECT_LIMIT; n++) {
241 const CodeSection* cs = code_section(n);
242 if (cs->allocates(addr)) return n;
243 }
244 return SECT_NONE;
245 }
246
247 int CodeBuffer::locator(address addr) const {
248 for (int n = 0; n < (int)SECT_LIMIT; n++) {
249 const CodeSection* cs = code_section(n);
250 if (cs->allocates(addr)) {
251 return locator(addr - cs->start(), n);
252 }
253 }
254 return -1;
255 }
256
257 address CodeBuffer::locator_address(int locator) const {
258 if (locator < 0) return NULL;
259 address start = code_section(locator_sect(locator))->start();
260 return start + locator_pos(locator);
261 }
262
263 bool CodeBuffer::is_backward_branch(Label& L) {
264 return L.is_bound() && insts_end() <= locator_address(L.loc());
265 }
266
267 address CodeBuffer::decode_begin() {
268 address begin = _insts.start();
269 if (_decode_begin != NULL && _decode_begin > begin)
270 begin = _decode_begin;
271 return begin;
272 }
273
274
275 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
276 if (_overflow_arena == NULL) {
277 _overflow_arena = new (mtCode) Arena(mtCode);
278 }
279 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
280 }
281
282
283 // Helper function for managing labels and their target addresses.
284 // Returns a sensible address, and if it is not the label's final
285 // address, notes the dependency (at 'branch_pc') on the label.
286 address CodeSection::target(Label& L, address branch_pc) {
287 if (L.is_bound()) {
288 int loc = L.loc();
289 if (index() == CodeBuffer::locator_sect(loc)) {
290 return start() + CodeBuffer::locator_pos(loc);
291 } else {
292 return outer()->locator_address(loc);
293 }
294 } else {
295 assert(allocates2(branch_pc), "sanity");
296 address base = start();
297 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
298 L.add_patch_at(outer(), patch_loc);
299
300 // Need to return a pc, doesn't matter what it is since it will be
301 // replaced during resolution later.
302 // Don't return NULL or badAddress, since branches shouldn't overflow.
303 // Don't return base either because that could overflow displacements
304 // for shorter branches. It will get checked when bound.
305 return branch_pc;
306 }
307 }
308
309 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) {
310 RelocationHolder rh;
311 switch (rtype) {
312 case relocInfo::none: return;
313 case relocInfo::opt_virtual_call_type: {
314 rh = opt_virtual_call_Relocation::spec(method_index);
315 break;
316 }
317 case relocInfo::static_call_type: {
318 rh = static_call_Relocation::spec(method_index);
319 break;
320 }
321 case relocInfo::virtual_call_type: {
322 assert(method_index == 0, "resolved method overriding is not supported");
323 rh = Relocation::spec_simple(rtype);
324 break;
325 }
326 default: {
327 rh = Relocation::spec_simple(rtype);
328 break;
329 }
330 }
331 relocate(at, rh, format);
332 }
333
334 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
335 // Do not relocate in scratch buffers.
336 if (scratch_emit()) { return; }
337 Relocation* reloc = spec.reloc();
338 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
339 if (rtype == relocInfo::none) return;
340
341 // The assertion below has been adjusted, to also work for
342 // relocation for fixup. Sometimes we want to put relocation
343 // information for the next instruction, since it will be patched
344 // with a call.
345 assert(start() <= at && at <= end()+1,
346 "cannot relocate data outside code boundaries");
347
348 if (!has_locs()) {
349 // no space for relocation information provided => code cannot be
350 // relocated. Make sure that relocate is only called with rtypes
351 // that can be ignored for this kind of code.
352 assert(rtype == relocInfo::none ||
353 rtype == relocInfo::runtime_call_type ||
354 rtype == relocInfo::internal_word_type||
355 rtype == relocInfo::section_word_type ||
356 rtype == relocInfo::external_word_type,
357 "code needs relocation information");
358 // leave behind an indication that we attempted a relocation
359 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
360 return;
361 }
362
363 // Advance the point, noting the offset we'll have to record.
364 csize_t offset = at - locs_point();
365 set_locs_point(at);
366
367 // Test for a couple of overflow conditions; maybe expand the buffer.
368 relocInfo* end = locs_end();
369 relocInfo* req = end + relocInfo::length_limit;
370 // Check for (potential) overflow
371 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
372 req += (uint)offset / (uint)relocInfo::offset_limit();
373 if (req >= locs_limit()) {
374 // Allocate or reallocate.
375 expand_locs(locs_count() + (req - end));
376 // reload pointer
377 end = locs_end();
378 }
379 }
380
381 // If the offset is giant, emit filler relocs, of type 'none', but
382 // each carrying the largest possible offset, to advance the locs_point.
383 while (offset >= relocInfo::offset_limit()) {
384 assert(end < locs_limit(), "adjust previous paragraph of code");
385 *end++ = filler_relocInfo();
386 offset -= filler_relocInfo().addr_offset();
387 }
388
389 // If it's a simple reloc with no data, we'll just write (rtype | offset).
390 (*end) = relocInfo(rtype, offset, format);
391
392 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
393 end->initialize(this, reloc);
394 }
395
396 void CodeSection::initialize_locs(int locs_capacity) {
397 assert(_locs_start == NULL, "only one locs init step, please");
398 // Apply a priori lower limits to relocation size:
399 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
400 if (locs_capacity < min_locs) locs_capacity = min_locs;
401 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
402 _locs_start = locs_start;
403 _locs_end = locs_start;
404 _locs_limit = locs_start + locs_capacity;
405 _locs_own = true;
406 }
407
408 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
409 assert(_locs_start == NULL, "do this before locs are allocated");
410 // Internal invariant: locs buf must be fully aligned.
411 // See copy_relocations_to() below.
412 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
413 ++buf; --length;
414 }
415 if (length > 0) {
416 _locs_start = buf;
417 _locs_end = buf;
418 _locs_limit = buf + length;
419 _locs_own = false;
420 }
421 }
422
423 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
424 int lcount = source_cs->locs_count();
425 if (lcount != 0) {
426 initialize_shared_locs(source_cs->locs_start(), lcount);
427 _locs_end = _locs_limit = _locs_start + lcount;
428 assert(is_allocated(), "must have copied code already");
429 set_locs_point(start() + source_cs->locs_point_off());
430 }
431 assert(this->locs_count() == source_cs->locs_count(), "sanity");
432 }
433
434 void CodeSection::expand_locs(int new_capacity) {
435 if (_locs_start == NULL) {
436 initialize_locs(new_capacity);
437 return;
438 } else {
439 int old_count = locs_count();
440 int old_capacity = locs_capacity();
441 if (new_capacity < old_capacity * 2)
442 new_capacity = old_capacity * 2;
443 relocInfo* locs_start;
444 if (_locs_own) {
445 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
446 } else {
447 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
448 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
449 _locs_own = true;
450 }
451 _locs_start = locs_start;
452 _locs_end = locs_start + old_count;
453 _locs_limit = locs_start + new_capacity;
454 }
455 }
456
457
458 /// Support for emitting the code to its final location.
459 /// The pattern is the same for all functions.
460 /// We iterate over all the sections, padding each to alignment.
461
462 csize_t CodeBuffer::total_content_size() const {
463 csize_t size_so_far = 0;
464 for (int n = 0; n < (int)SECT_LIMIT; n++) {
465 const CodeSection* cs = code_section(n);
466 if (cs->is_empty()) continue; // skip trivial section
467 size_so_far = cs->align_at_start(size_so_far);
468 size_so_far += cs->size();
469 }
470 return size_so_far;
471 }
472
473 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
474 address buf = dest->_total_start;
475 csize_t buf_offset = 0;
476 assert(dest->_total_size >= total_content_size(), "must be big enough");
477
478 {
479 // not sure why this is here, but why not...
480 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
481 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
482 }
483
484 const CodeSection* prev_cs = NULL;
485 CodeSection* prev_dest_cs = NULL;
486
487 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
488 // figure compact layout of each section
489 const CodeSection* cs = code_section(n);
490 csize_t csize = cs->size();
491
492 CodeSection* dest_cs = dest->code_section(n);
493 if (!cs->is_empty()) {
494 // Compute initial padding; assign it to the previous non-empty guy.
495 // Cf. figure_expanded_capacities.
496 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
497 if (prev_dest_cs != NULL) {
498 if (padding != 0) {
499 buf_offset += padding;
500 prev_dest_cs->_limit += padding;
501 }
502 } else {
503 guarantee(padding == 0, "In first iteration no padding should be needed.");
504 }
505 #ifdef ASSERT
506 if (prev_cs != NULL && prev_cs->is_frozen() && n < (SECT_LIMIT - 1)) {
507 // Make sure the ends still match up.
508 // This is important because a branch in a frozen section
509 // might target code in a following section, via a Label,
510 // and without a relocation record. See Label::patch_instructions.
511 address dest_start = buf+buf_offset;
512 csize_t start2start = cs->start() - prev_cs->start();
513 csize_t dest_start2start = dest_start - prev_dest_cs->start();
514 assert(start2start == dest_start2start, "cannot stretch frozen sect");
515 }
516 #endif //ASSERT
517 prev_dest_cs = dest_cs;
518 prev_cs = cs;
519 }
520
521 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert
522 dest_cs->initialize(buf+buf_offset, csize);
523 dest_cs->set_end(buf+buf_offset+csize);
524 assert(dest_cs->is_allocated(), "must always be allocated");
525 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
526
527 buf_offset += csize;
528 }
529
530 // Done calculating sections; did it come out to the right end?
531 assert(buf_offset == total_content_size(), "sanity");
532 dest->verify_section_allocation();
533 }
534
535 // Append an oop reference that keeps the class alive.
536 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) {
537 oop cl = k->klass_holder();
538 if (cl != NULL && !oops->contains(cl)) {
539 oops->append(cl);
540 }
541 }
542
543 void CodeBuffer::finalize_oop_references(const methodHandle& mh) {
544 NoSafepointVerifier nsv;
545
546 GrowableArray<oop> oops;
547
548 // Make sure that immediate metadata records something in the OopRecorder
549 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
550 // pull code out of each section
551 CodeSection* cs = code_section(n);
552 if (cs->is_empty()) continue; // skip trivial section
553 RelocIterator iter(cs);
554 while (iter.next()) {
555 if (iter.type() == relocInfo::metadata_type) {
556 metadata_Relocation* md = iter.metadata_reloc();
557 if (md->metadata_is_immediate()) {
558 Metadata* m = md->metadata_value();
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 // XXX This will currently occur for MDO which don't
570 // have a backpointer. This has to be fixed later.
571 m->print();
572 ShouldNotReachHere();
573 }
574 }
575 }
576 }
577 }
578 }
579
580 if (!oop_recorder()->is_unused()) {
581 for (int i = 0; i < oop_recorder()->metadata_count(); i++) {
582 Metadata* m = oop_recorder()->metadata_at(i);
583 if (oop_recorder()->is_real(m)) {
584 if (m->is_methodData()) {
585 m = ((MethodData*)m)->method();
586 }
587 if (m->is_method()) {
588 m = ((Method*)m)->method_holder();
589 }
590 if (m->is_klass()) {
591 append_oop_references(&oops, (Klass*)m);
592 } else {
593 m->print();
594 ShouldNotReachHere();
595 }
596 }
597 }
598
599 }
600
601 // Add the class loader of Method* for the nmethod itself
602 append_oop_references(&oops, mh->method_holder());
603
604 // Add any oops that we've found
605 Thread* thread = Thread::current();
606 for (int i = 0; i < oops.length(); i++) {
607 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i)));
608 }
609 }
610
611
612
613 csize_t CodeBuffer::total_offset_of(const CodeSection* cs) const {
614 csize_t size_so_far = 0;
615 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
616 const CodeSection* cur_cs = code_section(n);
617 if (!cur_cs->is_empty()) {
618 size_so_far = cur_cs->align_at_start(size_so_far);
619 }
620 if (cur_cs->index() == cs->index()) {
621 return size_so_far;
622 }
623 size_so_far += cur_cs->size();
624 }
625 ShouldNotReachHere();
626 return -1;
627 }
628
629 csize_t CodeBuffer::total_relocation_size() const {
630 csize_t total = copy_relocations_to(NULL); // dry run only
631 return (csize_t) align_up(total, HeapWordSize);
632 }
633
634 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const {
635 csize_t buf_offset = 0;
636 csize_t code_end_so_far = 0;
637 csize_t code_point_so_far = 0;
638
639 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
640 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
641
642 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
643 if (only_inst && (n != (int)SECT_INSTS)) {
644 // Need only relocation info for code.
645 continue;
646 }
647 // pull relocs out of each section
648 const CodeSection* cs = code_section(n);
649 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
650 if (cs->is_empty()) continue; // skip trivial section
651 relocInfo* lstart = cs->locs_start();
652 relocInfo* lend = cs->locs_end();
653 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
654 csize_t csize = cs->size();
655 code_end_so_far = cs->align_at_start(code_end_so_far);
656
657 if (lsize > 0) {
658 // Figure out how to advance the combined relocation point
659 // first to the beginning of this section.
660 // We'll insert one or more filler relocs to span that gap.
661 // (Don't bother to improve this by editing the first reloc's offset.)
662 csize_t new_code_point = code_end_so_far;
663 for (csize_t jump;
664 code_point_so_far < new_code_point;
665 code_point_so_far += jump) {
666 jump = new_code_point - code_point_so_far;
667 relocInfo filler = filler_relocInfo();
668 if (jump >= filler.addr_offset()) {
669 jump = filler.addr_offset();
670 } else { // else shrink the filler to fit
671 filler = relocInfo(relocInfo::none, jump);
672 }
673 if (buf != NULL) {
674 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
675 *(relocInfo*)(buf+buf_offset) = filler;
676 }
677 buf_offset += sizeof(filler);
678 }
679
680 // Update code point and end to skip past this section:
681 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
682 assert(code_point_so_far <= last_code_point, "sanity");
683 code_point_so_far = last_code_point; // advance past this guy's relocs
684 }
685 code_end_so_far += csize; // advance past this guy's instructions too
686
687 // Done with filler; emit the real relocations:
688 if (buf != NULL && lsize != 0) {
689 assert(buf_offset + lsize <= buf_limit, "target in bounds");
690 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
691 if (buf_offset % HeapWordSize == 0) {
692 // Use wordwise copies if possible:
693 Copy::disjoint_words((HeapWord*)lstart,
694 (HeapWord*)(buf+buf_offset),
695 (lsize + HeapWordSize-1) / HeapWordSize);
696 } else {
697 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
698 }
699 }
700 buf_offset += lsize;
701 }
702
703 // Align end of relocation info in target.
704 while (buf_offset % HeapWordSize != 0) {
705 if (buf != NULL) {
706 relocInfo padding = relocInfo(relocInfo::none, 0);
707 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
708 *(relocInfo*)(buf+buf_offset) = padding;
709 }
710 buf_offset += sizeof(relocInfo);
711 }
712
713 assert(only_inst || code_end_so_far == total_content_size(), "sanity");
714
715 return buf_offset;
716 }
717
718 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
719 address buf = NULL;
720 csize_t buf_offset = 0;
721 csize_t buf_limit = 0;
722
723 if (dest != NULL) {
724 buf = (address)dest->relocation_begin();
725 buf_limit = (address)dest->relocation_end() - buf;
726 }
727 // if dest == NULL, this is just the sizing pass
728 //
729 buf_offset = copy_relocations_to(buf, buf_limit, false);
730
731 return buf_offset;
732 }
733
734 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
735 #ifndef PRODUCT
736 if (PrintNMethods && (WizardMode || Verbose)) {
737 tty->print("done with CodeBuffer:");
738 ((CodeBuffer*)this)->print();
739 }
740 #endif //PRODUCT
741
742 CodeBuffer dest(dest_blob);
743 assert(dest_blob->content_size() >= total_content_size(), "good sizing");
744 this->compute_final_layout(&dest);
745
746 // Set beginning of constant table before relocating.
747 dest_blob->set_ctable_begin(dest.consts()->start());
748
749 relocate_code_to(&dest);
750
751 // transfer strings and comments from buffer to blob
752 dest_blob->set_strings(_code_strings);
753
754 // Done moving code bytes; were they the right size?
755 assert((int)align_up(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity");
756
757 // Flush generated code
758 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size());
759 }
760
761 // Move all my code into another code buffer. Consult applicable
762 // relocs to repair embedded addresses. The layout in the destination
763 // CodeBuffer is different to the source CodeBuffer: the destination
764 // CodeBuffer gets the final layout (consts, insts, stubs in order of
765 // ascending address).
766 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
767 address dest_end = dest->_total_start + dest->_total_size;
768 address dest_filled = NULL;
769 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
770 // pull code out of each section
771 const CodeSection* cs = code_section(n);
772 if (cs->is_empty()) continue; // skip trivial section
773 CodeSection* dest_cs = dest->code_section(n);
774 assert(cs->size() == dest_cs->size(), "sanity");
775 csize_t usize = dest_cs->size();
776 csize_t wsize = align_up(usize, HeapWordSize);
777 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
778 // Copy the code as aligned machine words.
779 // This may also include an uninitialized partial word at the end.
780 Copy::disjoint_words((HeapWord*)cs->start(),
781 (HeapWord*)dest_cs->start(),
782 wsize / HeapWordSize);
783
784 if (dest->blob() == NULL) {
785 // Destination is a final resting place, not just another buffer.
786 // Normalize uninitialized bytes in the final padding.
787 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
788 Assembler::code_fill_byte());
789 }
790 // Keep track of the highest filled address
791 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining());
792
793 assert(cs->locs_start() != (relocInfo*)badAddress,
794 "this section carries no reloc storage, but reloc was attempted");
795
796 // Make the new code copy use the old copy's relocations:
797 dest_cs->initialize_locs_from(cs);
798 }
799
800 // Do relocation after all sections are copied.
801 // This is necessary if the code uses constants in stubs, which are
802 // relocated when the corresponding instruction in the code (e.g., a
803 // call) is relocated. Stubs are placed behind the main code
804 // section, so that section has to be copied before relocating.
805 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) {
806 // pull code out of each section
807 const CodeSection* cs = code_section(n);
808 if (cs->is_empty()) continue; // skip trivial section
809 CodeSection* dest_cs = dest->code_section(n);
810 { // Repair the pc relative information in the code after the move
811 RelocIterator iter(dest_cs);
812 while (iter.next()) {
813 iter.reloc()->fix_relocation_after_move(this, dest);
814 }
815 }
816 }
817
818 if (dest->blob() == NULL && dest_filled != NULL) {
819 // Destination is a final resting place, not just another buffer.
820 // Normalize uninitialized bytes in the final padding.
821 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled,
822 Assembler::code_fill_byte());
823
824 }
825 }
826
827 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
828 csize_t amount,
829 csize_t* new_capacity) {
830 csize_t new_total_cap = 0;
831
832 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
833 const CodeSection* sect = code_section(n);
834
835 if (!sect->is_empty()) {
836 // Compute initial padding; assign it to the previous section,
837 // even if it's empty (e.g. consts section can be empty).
838 // Cf. compute_final_layout
839 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
840 if (padding != 0) {
841 new_total_cap += padding;
842 assert(n - 1 >= SECT_FIRST, "sanity");
843 new_capacity[n - 1] += padding;
844 }
845 }
846
847 csize_t exp = sect->size(); // 100% increase
848 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
849 if (sect == which_cs) {
850 if (exp < amount) exp = amount;
851 if (StressCodeBuffers) exp = amount; // expand only slightly
852 } else if (n == SECT_INSTS) {
853 // scale down inst increases to a more modest 25%
854 exp = 4*K + ((exp - 4*K) >> 2);
855 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
856 } else if (sect->is_empty()) {
857 // do not grow an empty secondary section
858 exp = 0;
859 }
860 // Allow for inter-section slop:
861 exp += CodeSection::end_slop();
862 csize_t new_cap = sect->size() + exp;
863 if (new_cap < sect->capacity()) {
864 // No need to expand after all.
865 new_cap = sect->capacity();
866 }
867 new_capacity[n] = new_cap;
868 new_total_cap += new_cap;
869 }
870
871 return new_total_cap;
872 }
873
874 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
875 #ifndef PRODUCT
876 if (PrintNMethods && (WizardMode || Verbose)) {
877 tty->print("expanding CodeBuffer:");
878 this->print();
879 }
880
881 if (StressCodeBuffers && blob() != NULL) {
882 static int expand_count = 0;
883 if (expand_count >= 0) expand_count += 1;
884 if (expand_count > 100 && is_power_of_2(expand_count)) {
885 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
886 // simulate an occasional allocation failure:
887 free_blob();
888 }
889 }
890 #endif //PRODUCT
891
892 // Resizing must be allowed
893 {
894 if (blob() == NULL) return; // caller must check for blob == NULL
895 for (int n = 0; n < (int)SECT_LIMIT; n++) {
896 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen");
897 }
898 }
899
900 // Figure new capacity for each section.
901 csize_t new_capacity[SECT_LIMIT];
902 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT);
903 csize_t new_total_cap
904 = figure_expanded_capacities(which_cs, amount, new_capacity);
905
906 // Create a new (temporary) code buffer to hold all the new data
907 CodeBuffer cb(name(), new_total_cap, 0);
908 if (cb.blob() == NULL) {
909 // Failed to allocate in code cache.
910 free_blob();
911 return;
912 }
913
914 // Create an old code buffer to remember which addresses used to go where.
915 // This will be useful when we do final assembly into the code cache,
916 // because we will need to know how to warp any internal address that
917 // has been created at any time in this CodeBuffer's past.
918 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
919 bxp->take_over_code_from(this); // remember the old undersized blob
920 DEBUG_ONLY(this->_blob = NULL); // silence a later assert
921 bxp->_before_expand = this->_before_expand;
922 this->_before_expand = bxp;
923
924 // Give each section its required (expanded) capacity.
925 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) {
926 CodeSection* cb_sect = cb.code_section(n);
927 CodeSection* this_sect = code_section(n);
928 if (new_capacity[n] == 0) continue; // already nulled out
929 if (n != SECT_INSTS) {
930 cb.initialize_section_size(cb_sect, new_capacity[n]);
931 }
932 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
933 address cb_start = cb_sect->start();
934 cb_sect->set_end(cb_start + this_sect->size());
935 if (this_sect->mark() == NULL) {
936 cb_sect->clear_mark();
937 } else {
938 cb_sect->set_mark(cb_start + this_sect->mark_off());
939 }
940 }
941
942 // Needs to be initialized when calling fix_relocation_after_move.
943 cb.blob()->set_ctable_begin(cb.consts()->start());
944
945 // Move all the code and relocations to the new blob:
946 relocate_code_to(&cb);
947
948 // Copy the temporary code buffer into the current code buffer.
949 // Basically, do {*this = cb}, except for some control information.
950 this->take_over_code_from(&cb);
951 cb.set_blob(NULL);
952
953 // Zap the old code buffer contents, to avoid mistakenly using them.
954 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
955 badCodeHeapFreeVal));
956
957 _decode_begin = NULL; // sanity
958
959 // Make certain that the new sections are all snugly inside the new blob.
960 verify_section_allocation();
961
962 #ifndef PRODUCT
963 if (PrintNMethods && (WizardMode || Verbose)) {
964 tty->print("expanded CodeBuffer:");
965 this->print();
966 }
967 #endif //PRODUCT
968 }
969
970 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
971 // Must already have disposed of the old blob somehow.
972 assert(blob() == NULL, "must be empty");
973 // Take the new blob away from cb.
974 set_blob(cb->blob());
975 // Take over all the section pointers.
976 for (int n = 0; n < (int)SECT_LIMIT; n++) {
977 CodeSection* cb_sect = cb->code_section(n);
978 CodeSection* this_sect = code_section(n);
979 this_sect->take_over_code_from(cb_sect);
980 }
981 _overflow_arena = cb->_overflow_arena;
982 // Make sure the old cb won't try to use it or free it.
983 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
984 }
985
986 void CodeBuffer::verify_section_allocation() {
987 address tstart = _total_start;
988 if (tstart == badAddress) return; // smashed by set_blob(NULL)
989 address tend = tstart + _total_size;
990 if (_blob != NULL) {
991
992 guarantee(tstart >= _blob->content_begin(), "sanity");
993 guarantee(tend <= _blob->content_end(), "sanity");
994 }
995 // Verify disjointness.
996 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) {
997 CodeSection* sect = code_section(n);
998 if (!sect->is_allocated() || sect->is_empty()) continue;
999 guarantee((intptr_t)sect->start() % sect->alignment() == 0
1000 || sect->is_empty() || _blob == NULL,
1001 "start is aligned");
1002 for (int m = (int) SECT_FIRST; m < (int) SECT_LIMIT; m++) {
1003 CodeSection* other = code_section(m);
1004 if (!other->is_allocated() || other == sect) continue;
1005 guarantee(!other->contains(sect->start() ), "sanity");
1006 // limit is an exclusive address and can be the start of another
1007 // section.
1008 guarantee(!other->contains(sect->limit() - 1), "sanity");
1009 }
1010 guarantee(sect->end() <= tend, "sanity");
1011 guarantee(sect->end() <= sect->limit(), "sanity");
1012 }
1013 }
1014
1015 void CodeBuffer::log_section_sizes(const char* name) {
1016 if (xtty != NULL) {
1017 ttyLocker ttyl;
1018 // log info about buffer usage
1019 xtty->print_cr("<blob name='%s' size='%d'>", name, _total_size);
1020 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
1021 CodeSection* sect = code_section(n);
1022 if (!sect->is_allocated() || sect->is_empty()) continue;
1023 xtty->print_cr("<sect index='%d' size='" SIZE_FORMAT "' free='" SIZE_FORMAT "'/>",
1024 n, sect->limit() - sect->start(), sect->limit() - sect->end());
1025 }
1026 xtty->print_cr("</blob>");
1027 }
1028 }
1029
1030 #ifndef PRODUCT
1031
1032 void CodeSection::dump() {
1033 address ptr = start();
1034 for (csize_t step; ptr < end(); ptr += step) {
1035 step = end() - ptr;
1036 if (step > jintSize * 4) step = jintSize * 4;
1037 tty->print(INTPTR_FORMAT ": ", p2i(ptr));
1038 while (step > 0) {
1039 tty->print(" " PTR32_FORMAT, *(jint*)ptr);
1040 ptr += jintSize;
1041 }
1042 tty->cr();
1043 }
1044 }
1045
1046
1047 void CodeSection::decode() {
1048 Disassembler::decode(start(), end());
1049 }
1050
1051
1052 void CodeBuffer::block_comment(intptr_t offset, const char * comment) {
1053 _code_strings.add_comment(offset, comment);
1054 }
1055
1056 const char* CodeBuffer::code_string(const char* str) {
1057 return _code_strings.add_string(str);
1058 }
1059
1060 class CodeString: public CHeapObj<mtCode> {
1061 private:
1062 friend class CodeStrings;
1063 const char * _string;
1064 CodeString* _next;
1065 intptr_t _offset;
1066
1067 ~CodeString() {
1068 assert(_next == NULL, "wrong interface for freeing list");
1069 os::free((void*)_string);
1070 }
1071
1072 bool is_comment() const { return _offset >= 0; }
1073
1074 public:
1075 CodeString(const char * string, intptr_t offset = -1)
1076 : _next(NULL), _offset(offset) {
1077 _string = os::strdup(string, mtCode);
1078 }
1079
1080 const char * string() const { return _string; }
1081 intptr_t offset() const { assert(_offset >= 0, "offset for non comment?"); return _offset; }
1082 CodeString* next() const { return _next; }
1083
1084 void set_next(CodeString* next) { _next = next; }
1085
1086 CodeString* first_comment() {
1087 if (is_comment()) {
1088 return this;
1089 } else {
1090 return next_comment();
1091 }
1092 }
1093 CodeString* next_comment() const {
1094 CodeString* s = _next;
1095 while (s != NULL && !s->is_comment()) {
1096 s = s->_next;
1097 }
1098 return s;
1099 }
1100 };
1101
1102 CodeString* CodeStrings::find(intptr_t offset) const {
1103 CodeString* a = _strings->first_comment();
1104 while (a != NULL && a->offset() != offset) {
1105 a = a->next_comment();
1106 }
1107 return a;
1108 }
1109
1110 // Convenience for add_comment.
1111 CodeString* CodeStrings::find_last(intptr_t offset) const {
1112 CodeString* a = find(offset);
1113 if (a != NULL) {
1114 CodeString* c = NULL;
1115 while (((c = a->next_comment()) != NULL) && (c->offset() == offset)) {
1116 a = c;
1117 }
1118 }
1119 return a;
1120 }
1121
1122 void CodeStrings::add_comment(intptr_t offset, const char * comment) {
1123 check_valid();
1124 CodeString* c = new CodeString(comment, offset);
1125 CodeString* inspos = (_strings == NULL) ? NULL : find_last(offset);
1126
1127 if (inspos) {
1128 // insert after already existing comments with same offset
1129 c->set_next(inspos->next());
1130 inspos->set_next(c);
1131 } else {
1132 // no comments with such offset, yet. Insert before anything else.
1133 c->set_next(_strings);
1134 _strings = c;
1135 }
1136 }
1137
1138 void CodeStrings::assign(CodeStrings& other) {
1139 other.check_valid();
1140 assert(is_null(), "Cannot assign onto non-empty CodeStrings");
1141 _strings = other._strings;
1142 #ifdef ASSERT
1143 _defunct = false;
1144 #endif
1145 other.set_null_and_invalidate();
1146 }
1147
1148 // Deep copy of CodeStrings for consistent memory management.
1149 // Only used for actual disassembly so this is cheaper than reference counting
1150 // for the "normal" fastdebug case.
1151 void CodeStrings::copy(CodeStrings& other) {
1152 other.check_valid();
1153 check_valid();
1154 assert(is_null(), "Cannot copy onto non-empty CodeStrings");
1155 CodeString* n = other._strings;
1156 CodeString** ps = &_strings;
1157 while (n != NULL) {
1158 *ps = new CodeString(n->string(),n->offset());
1159 ps = &((*ps)->_next);
1160 n = n->next();
1161 }
1162 }
1163
1164 const char* CodeStrings::_prefix = " ;; "; // default: can be changed via set_prefix
1165
1166 void CodeStrings::print_block_comment(outputStream* stream, intptr_t offset) const {
1167 check_valid();
1168 if (_strings != NULL) {
1169 CodeString* c = find(offset);
1170 while (c && c->offset() == offset) {
1171 stream->bol();
1172 stream->print("%s", _prefix);
1173 // Don't interpret as format strings since it could contain %
1174 stream->print_raw_cr(c->string());
1175 c = c->next_comment();
1176 }
1177 }
1178 }
1179
1180 // Also sets isNull()
1181 void CodeStrings::free() {
1182 CodeString* n = _strings;
1183 while (n) {
1184 // unlink the node from the list saving a pointer to the next
1185 CodeString* p = n->next();
1186 n->set_next(NULL);
1187 delete n;
1188 n = p;
1189 }
1190 set_null_and_invalidate();
1191 }
1192
1193 const char* CodeStrings::add_string(const char * string) {
1194 check_valid();
1195 CodeString* s = new CodeString(string);
1196 s->set_next(_strings);
1197 _strings = s;
1198 assert(s->string() != NULL, "should have a string");
1199 return s->string();
1200 }
1201
1202 void CodeBuffer::decode() {
1203 ttyLocker ttyl;
1204 Disassembler::decode(decode_begin(), insts_end());
1205 _decode_begin = insts_end();
1206 }
1207
1208
1209 void CodeBuffer::skip_decode() {
1210 _decode_begin = insts_end();
1211 }
1212
1213
1214 void CodeBuffer::decode_all() {
1215 ttyLocker ttyl;
1216 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1217 // dump contents of each section
1218 CodeSection* cs = code_section(n);
1219 tty->print_cr("! %s:", code_section_name(n));
1220 if (cs != consts())
1221 cs->decode();
1222 else
1223 cs->dump();
1224 }
1225 }
1226
1227
1228 void CodeSection::print(const char* name) {
1229 csize_t locs_size = locs_end() - locs_start();
1230 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s",
1231 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity(),
1232 is_frozen()? " [frozen]": "");
1233 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1234 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off());
1235 if (PrintRelocations) {
1236 RelocIterator iter(this);
1237 iter.print();
1238 }
1239 }
1240
1241 void CodeBuffer::print() {
1242 if (this == NULL) {
1243 tty->print_cr("NULL CodeBuffer pointer");
1244 return;
1245 }
1246
1247 tty->print_cr("CodeBuffer:");
1248 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1249 // print each section
1250 CodeSection* cs = code_section(n);
1251 cs->print(code_section_name(n));
1252 }
1253 }
1254
1255 #endif // PRODUCT