comparison src/share/vm/asm/codeBuffer.cpp @ 0:a61af66fc99e jdk7-b24

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author duke
date Sat, 01 Dec 2007 00:00:00 +0000
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1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_codeBuffer.cpp.incl"
27
28 // The structure of a CodeSection:
29 //
30 // _start -> +----------------+
31 // | machine code...|
32 // _end -> |----------------|
33 // | |
34 // | (empty) |
35 // | |
36 // | |
37 // +----------------+
38 // _limit -> | |
39 //
40 // _locs_start -> +----------------+
41 // |reloc records...|
42 // |----------------|
43 // _locs_end -> | |
44 // | |
45 // | (empty) |
46 // | |
47 // | |
48 // +----------------+
49 // _locs_limit -> | |
50 // The _end (resp. _limit) pointer refers to the first
51 // unused (resp. unallocated) byte.
52
53 // The structure of the CodeBuffer while code is being accumulated:
54 //
55 // _total_start -> \
56 // _insts._start -> +----------------+
57 // | |
58 // | Code |
59 // | |
60 // _stubs._start -> |----------------|
61 // | |
62 // | Stubs | (also handlers for deopt/exception)
63 // | |
64 // _consts._start -> |----------------|
65 // | |
66 // | Constants |
67 // | |
68 // +----------------+
69 // + _total_size -> | |
70 //
71 // When the code and relocations are copied to the code cache,
72 // the empty parts of each section are removed, and everything
73 // is copied into contiguous locations.
74
75 typedef CodeBuffer::csize_t csize_t; // file-local definition
76
77 // external buffer, in a predefined CodeBlob or other buffer area
78 // Important: The code_start must be taken exactly, and not realigned.
79 CodeBuffer::CodeBuffer(address code_start, csize_t code_size) {
80 assert(code_start != NULL, "sanity");
81 initialize_misc("static buffer");
82 initialize(code_start, code_size);
83 assert(verify_section_allocation(), "initial use of buffer OK");
84 }
85
86 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
87 // Compute maximal alignment.
88 int align = _insts.alignment();
89 // Always allow for empty slop around each section.
90 int slop = (int) CodeSection::end_slop();
91
92 assert(blob() == NULL, "only once");
93 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1)));
94 if (blob() == NULL) {
95 // The assembler constructor will throw a fatal on an empty CodeBuffer.
96 return; // caller must test this
97 }
98
99 // Set up various pointers into the blob.
100 initialize(_total_start, _total_size);
101
102 assert((uintptr_t)code_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
103
104 pd_initialize();
105
106 if (locs_size != 0) {
107 _insts.initialize_locs(locs_size / sizeof(relocInfo));
108 }
109
110 assert(verify_section_allocation(), "initial use of blob is OK");
111 }
112
113
114 CodeBuffer::~CodeBuffer() {
115 // If we allocate our code buffer from the CodeCache
116 // via a BufferBlob, and it's not permanent, then
117 // free the BufferBlob.
118 // The rest of the memory will be freed when the ResourceObj
119 // is released.
120 assert(verify_section_allocation(), "final storage configuration still OK");
121 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) {
122 // Previous incarnations of this buffer are held live, so that internal
123 // addresses constructed before expansions will not be confused.
124 cb->free_blob();
125 }
126 #ifdef ASSERT
127 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue);
128 #endif
129 }
130
131 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
132 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
133 DEBUG_ONLY(_default_oop_recorder.oop_size()); // force unused OR to be frozen
134 _oop_recorder = r;
135 }
136
137 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
138 assert(cs != &_insts, "insts is the memory provider, not the consumer");
139 #ifdef ASSERT
140 for (int n = (int)SECT_INSTS+1; n < (int)SECT_LIMIT; n++) {
141 CodeSection* prevCS = code_section(n);
142 if (prevCS == cs) break;
143 assert(!prevCS->is_allocated(), "section allocation must be in reverse order");
144 }
145 #endif
146 csize_t slop = CodeSection::end_slop(); // margin between sections
147 int align = cs->alignment();
148 assert(is_power_of_2(align), "sanity");
149 address start = _insts._start;
150 address limit = _insts._limit;
151 address middle = limit - size;
152 middle -= (intptr_t)middle & (align-1); // align the division point downward
153 guarantee(middle - slop > start, "need enough space to divide up");
154 _insts._limit = middle - slop; // subtract desired space, plus slop
155 cs->initialize(middle, limit - middle);
156 assert(cs->start() == middle, "sanity");
157 assert(cs->limit() == limit, "sanity");
158 // give it some relocations to start with, if the main section has them
159 if (_insts.has_locs()) cs->initialize_locs(1);
160 }
161
162 void CodeBuffer::freeze_section(CodeSection* cs) {
163 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1);
164 csize_t frozen_size = cs->size();
165 if (next_cs != NULL) {
166 frozen_size = next_cs->align_at_start(frozen_size);
167 }
168 address old_limit = cs->limit();
169 address new_limit = cs->start() + frozen_size;
170 relocInfo* old_locs_limit = cs->locs_limit();
171 relocInfo* new_locs_limit = cs->locs_end();
172 // Patch the limits.
173 cs->_limit = new_limit;
174 cs->_locs_limit = new_locs_limit;
175 cs->_frozen = true;
176 if (!next_cs->is_allocated() && !next_cs->is_frozen()) {
177 // Give remaining buffer space to the following section.
178 next_cs->initialize(new_limit, old_limit - new_limit);
179 next_cs->initialize_shared_locs(new_locs_limit,
180 old_locs_limit - new_locs_limit);
181 }
182 }
183
184 void CodeBuffer::set_blob(BufferBlob* blob) {
185 _blob = blob;
186 if (blob != NULL) {
187 address start = blob->instructions_begin();
188 address end = blob->instructions_end();
189 // Round up the starting address.
190 int align = _insts.alignment();
191 start += (-(intptr_t)start) & (align-1);
192 _total_start = start;
193 _total_size = end - start;
194 } else {
195 #ifdef ASSERT
196 // Clean out dangling pointers.
197 _total_start = badAddress;
198 _insts._start = _insts._end = badAddress;
199 _stubs._start = _stubs._end = badAddress;
200 _consts._start = _consts._end = badAddress;
201 #endif //ASSERT
202 }
203 }
204
205 void CodeBuffer::free_blob() {
206 if (_blob != NULL) {
207 BufferBlob::free(_blob);
208 set_blob(NULL);
209 }
210 }
211
212 const char* CodeBuffer::code_section_name(int n) {
213 #ifdef PRODUCT
214 return NULL;
215 #else //PRODUCT
216 switch (n) {
217 case SECT_INSTS: return "insts";
218 case SECT_STUBS: return "stubs";
219 case SECT_CONSTS: return "consts";
220 default: return NULL;
221 }
222 #endif //PRODUCT
223 }
224
225 int CodeBuffer::section_index_of(address addr) const {
226 for (int n = 0; n < (int)SECT_LIMIT; n++) {
227 const CodeSection* cs = code_section(n);
228 if (cs->allocates(addr)) return n;
229 }
230 return SECT_NONE;
231 }
232
233 int CodeBuffer::locator(address addr) const {
234 for (int n = 0; n < (int)SECT_LIMIT; n++) {
235 const CodeSection* cs = code_section(n);
236 if (cs->allocates(addr)) {
237 return locator(addr - cs->start(), n);
238 }
239 }
240 return -1;
241 }
242
243 address CodeBuffer::locator_address(int locator) const {
244 if (locator < 0) return NULL;
245 address start = code_section(locator_sect(locator))->start();
246 return start + locator_pos(locator);
247 }
248
249 address CodeBuffer::decode_begin() {
250 address begin = _insts.start();
251 if (_decode_begin != NULL && _decode_begin > begin)
252 begin = _decode_begin;
253 return begin;
254 }
255
256
257 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
258 if (_overflow_arena == NULL) {
259 _overflow_arena = new Arena();
260 }
261 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
262 }
263
264
265 // Helper function for managing labels and their target addresses.
266 // Returns a sensible address, and if it is not the label's final
267 // address, notes the dependency (at 'branch_pc') on the label.
268 address CodeSection::target(Label& L, address branch_pc) {
269 if (L.is_bound()) {
270 int loc = L.loc();
271 if (index() == CodeBuffer::locator_sect(loc)) {
272 return start() + CodeBuffer::locator_pos(loc);
273 } else {
274 return outer()->locator_address(loc);
275 }
276 } else {
277 assert(allocates2(branch_pc), "sanity");
278 address base = start();
279 int patch_loc = CodeBuffer::locator(branch_pc - base, index());
280 L.add_patch_at(outer(), patch_loc);
281
282 // Need to return a pc, doesn't matter what it is since it will be
283 // replaced during resolution later.
284 // (Don't return NULL or badAddress, since branches shouldn't overflow.)
285 return base;
286 }
287 }
288
289 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
290 Relocation* reloc = spec.reloc();
291 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
292 if (rtype == relocInfo::none) return;
293
294 // The assertion below has been adjusted, to also work for
295 // relocation for fixup. Sometimes we want to put relocation
296 // information for the next instruction, since it will be patched
297 // with a call.
298 assert(start() <= at && at <= end()+1,
299 "cannot relocate data outside code boundaries");
300
301 if (!has_locs()) {
302 // no space for relocation information provided => code cannot be
303 // relocated. Make sure that relocate is only called with rtypes
304 // that can be ignored for this kind of code.
305 assert(rtype == relocInfo::none ||
306 rtype == relocInfo::runtime_call_type ||
307 rtype == relocInfo::internal_word_type||
308 rtype == relocInfo::section_word_type ||
309 rtype == relocInfo::external_word_type,
310 "code needs relocation information");
311 // leave behind an indication that we attempted a relocation
312 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
313 return;
314 }
315
316 // Advance the point, noting the offset we'll have to record.
317 csize_t offset = at - locs_point();
318 set_locs_point(at);
319
320 // Test for a couple of overflow conditions; maybe expand the buffer.
321 relocInfo* end = locs_end();
322 relocInfo* req = end + relocInfo::length_limit;
323 // Check for (potential) overflow
324 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
325 req += (uint)offset / (uint)relocInfo::offset_limit();
326 if (req >= locs_limit()) {
327 // Allocate or reallocate.
328 expand_locs(locs_count() + (req - end));
329 // reload pointer
330 end = locs_end();
331 }
332 }
333
334 // If the offset is giant, emit filler relocs, of type 'none', but
335 // each carrying the largest possible offset, to advance the locs_point.
336 while (offset >= relocInfo::offset_limit()) {
337 assert(end < locs_limit(), "adjust previous paragraph of code");
338 *end++ = filler_relocInfo();
339 offset -= filler_relocInfo().addr_offset();
340 }
341
342 // If it's a simple reloc with no data, we'll just write (rtype | offset).
343 (*end) = relocInfo(rtype, offset, format);
344
345 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
346 end->initialize(this, reloc);
347 }
348
349 void CodeSection::initialize_locs(int locs_capacity) {
350 assert(_locs_start == NULL, "only one locs init step, please");
351 // Apply a priori lower limits to relocation size:
352 csize_t min_locs = MAX2(size() / 16, (csize_t)4);
353 if (locs_capacity < min_locs) locs_capacity = min_locs;
354 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
355 _locs_start = locs_start;
356 _locs_end = locs_start;
357 _locs_limit = locs_start + locs_capacity;
358 _locs_own = true;
359 }
360
361 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
362 assert(_locs_start == NULL, "do this before locs are allocated");
363 // Internal invariant: locs buf must be fully aligned.
364 // See copy_relocations_to() below.
365 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
366 ++buf; --length;
367 }
368 if (length > 0) {
369 _locs_start = buf;
370 _locs_end = buf;
371 _locs_limit = buf + length;
372 _locs_own = false;
373 }
374 }
375
376 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
377 int lcount = source_cs->locs_count();
378 if (lcount != 0) {
379 initialize_shared_locs(source_cs->locs_start(), lcount);
380 _locs_end = _locs_limit = _locs_start + lcount;
381 assert(is_allocated(), "must have copied code already");
382 set_locs_point(start() + source_cs->locs_point_off());
383 }
384 assert(this->locs_count() == source_cs->locs_count(), "sanity");
385 }
386
387 void CodeSection::expand_locs(int new_capacity) {
388 if (_locs_start == NULL) {
389 initialize_locs(new_capacity);
390 return;
391 } else {
392 int old_count = locs_count();
393 int old_capacity = locs_capacity();
394 if (new_capacity < old_capacity * 2)
395 new_capacity = old_capacity * 2;
396 relocInfo* locs_start;
397 if (_locs_own) {
398 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
399 } else {
400 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
401 Copy::conjoint_bytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
402 _locs_own = true;
403 }
404 _locs_start = locs_start;
405 _locs_end = locs_start + old_count;
406 _locs_limit = locs_start + new_capacity;
407 }
408 }
409
410
411 /// Support for emitting the code to its final location.
412 /// The pattern is the same for all functions.
413 /// We iterate over all the sections, padding each to alignment.
414
415 csize_t CodeBuffer::total_code_size() const {
416 csize_t code_size_so_far = 0;
417 for (int n = 0; n < (int)SECT_LIMIT; n++) {
418 const CodeSection* cs = code_section(n);
419 if (cs->is_empty()) continue; // skip trivial section
420 code_size_so_far = cs->align_at_start(code_size_so_far);
421 code_size_so_far += cs->size();
422 }
423 return code_size_so_far;
424 }
425
426 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
427 address buf = dest->_total_start;
428 csize_t buf_offset = 0;
429 assert(dest->_total_size >= total_code_size(), "must be big enough");
430
431 {
432 // not sure why this is here, but why not...
433 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
434 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
435 }
436
437 const CodeSection* prev_cs = NULL;
438 CodeSection* prev_dest_cs = NULL;
439 for (int n = 0; n < (int)SECT_LIMIT; n++) {
440 // figure compact layout of each section
441 const CodeSection* cs = code_section(n);
442 address cstart = cs->start();
443 address cend = cs->end();
444 csize_t csize = cend - cstart;
445
446 CodeSection* dest_cs = dest->code_section(n);
447 if (!cs->is_empty()) {
448 // Compute initial padding; assign it to the previous non-empty guy.
449 // Cf. figure_expanded_capacities.
450 csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
451 if (padding != 0) {
452 buf_offset += padding;
453 assert(prev_dest_cs != NULL, "sanity");
454 prev_dest_cs->_limit += padding;
455 }
456 #ifdef ASSERT
457 if (prev_cs != NULL && prev_cs->is_frozen() && n < SECT_CONSTS) {
458 // Make sure the ends still match up.
459 // This is important because a branch in a frozen section
460 // might target code in a following section, via a Label,
461 // and without a relocation record. See Label::patch_instructions.
462 address dest_start = buf+buf_offset;
463 csize_t start2start = cs->start() - prev_cs->start();
464 csize_t dest_start2start = dest_start - prev_dest_cs->start();
465 assert(start2start == dest_start2start, "cannot stretch frozen sect");
466 }
467 #endif //ASSERT
468 prev_dest_cs = dest_cs;
469 prev_cs = cs;
470 }
471
472 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert
473 dest_cs->initialize(buf+buf_offset, csize);
474 dest_cs->set_end(buf+buf_offset+csize);
475 assert(dest_cs->is_allocated(), "must always be allocated");
476 assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
477
478 buf_offset += csize;
479 }
480
481 // Done calculating sections; did it come out to the right end?
482 assert(buf_offset == total_code_size(), "sanity");
483 assert(dest->verify_section_allocation(), "final configuration works");
484 }
485
486 csize_t CodeBuffer::total_offset_of(address addr) const {
487 csize_t code_size_so_far = 0;
488 for (int n = 0; n < (int)SECT_LIMIT; n++) {
489 const CodeSection* cs = code_section(n);
490 if (!cs->is_empty()) {
491 code_size_so_far = cs->align_at_start(code_size_so_far);
492 }
493 if (cs->contains2(addr)) {
494 return code_size_so_far + (addr - cs->start());
495 }
496 code_size_so_far += cs->size();
497 }
498 #ifndef PRODUCT
499 tty->print_cr("Dangling address " PTR_FORMAT " in:", addr);
500 ((CodeBuffer*)this)->print();
501 #endif
502 ShouldNotReachHere();
503 return -1;
504 }
505
506 csize_t CodeBuffer::total_relocation_size() const {
507 csize_t lsize = copy_relocations_to(NULL); // dry run only
508 csize_t csize = total_code_size();
509 csize_t total = RelocIterator::locs_and_index_size(csize, lsize);
510 return (csize_t) align_size_up(total, HeapWordSize);
511 }
512
513 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
514 address buf = NULL;
515 csize_t buf_offset = 0;
516 csize_t buf_limit = 0;
517 if (dest != NULL) {
518 buf = (address)dest->relocation_begin();
519 buf_limit = (address)dest->relocation_end() - buf;
520 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
521 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
522 }
523 // if dest == NULL, this is just the sizing pass
524
525 csize_t code_end_so_far = 0;
526 csize_t code_point_so_far = 0;
527 for (int n = 0; n < (int)SECT_LIMIT; n++) {
528 // pull relocs out of each section
529 const CodeSection* cs = code_section(n);
530 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
531 if (cs->is_empty()) continue; // skip trivial section
532 relocInfo* lstart = cs->locs_start();
533 relocInfo* lend = cs->locs_end();
534 csize_t lsize = (csize_t)( (address)lend - (address)lstart );
535 csize_t csize = cs->size();
536 code_end_so_far = cs->align_at_start(code_end_so_far);
537
538 if (lsize > 0) {
539 // Figure out how to advance the combined relocation point
540 // first to the beginning of this section.
541 // We'll insert one or more filler relocs to span that gap.
542 // (Don't bother to improve this by editing the first reloc's offset.)
543 csize_t new_code_point = code_end_so_far;
544 for (csize_t jump;
545 code_point_so_far < new_code_point;
546 code_point_so_far += jump) {
547 jump = new_code_point - code_point_so_far;
548 relocInfo filler = filler_relocInfo();
549 if (jump >= filler.addr_offset()) {
550 jump = filler.addr_offset();
551 } else { // else shrink the filler to fit
552 filler = relocInfo(relocInfo::none, jump);
553 }
554 if (buf != NULL) {
555 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
556 *(relocInfo*)(buf+buf_offset) = filler;
557 }
558 buf_offset += sizeof(filler);
559 }
560
561 // Update code point and end to skip past this section:
562 csize_t last_code_point = code_end_so_far + cs->locs_point_off();
563 assert(code_point_so_far <= last_code_point, "sanity");
564 code_point_so_far = last_code_point; // advance past this guy's relocs
565 }
566 code_end_so_far += csize; // advance past this guy's instructions too
567
568 // Done with filler; emit the real relocations:
569 if (buf != NULL && lsize != 0) {
570 assert(buf_offset + lsize <= buf_limit, "target in bounds");
571 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
572 if (buf_offset % HeapWordSize == 0) {
573 // Use wordwise copies if possible:
574 Copy::disjoint_words((HeapWord*)lstart,
575 (HeapWord*)(buf+buf_offset),
576 (lsize + HeapWordSize-1) / HeapWordSize);
577 } else {
578 Copy::conjoint_bytes(lstart, buf+buf_offset, lsize);
579 }
580 }
581 buf_offset += lsize;
582 }
583
584 // Align end of relocation info in target.
585 while (buf_offset % HeapWordSize != 0) {
586 if (buf != NULL) {
587 relocInfo padding = relocInfo(relocInfo::none, 0);
588 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
589 *(relocInfo*)(buf+buf_offset) = padding;
590 }
591 buf_offset += sizeof(relocInfo);
592 }
593
594 assert(code_end_so_far == total_code_size(), "sanity");
595
596 // Account for index:
597 if (buf != NULL) {
598 RelocIterator::create_index(dest->relocation_begin(),
599 buf_offset / sizeof(relocInfo),
600 dest->relocation_end());
601 }
602
603 return buf_offset;
604 }
605
606 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
607 #ifndef PRODUCT
608 if (PrintNMethods && (WizardMode || Verbose)) {
609 tty->print("done with CodeBuffer:");
610 ((CodeBuffer*)this)->print();
611 }
612 #endif //PRODUCT
613
614 CodeBuffer dest(dest_blob->instructions_begin(),
615 dest_blob->instructions_size());
616 assert(dest_blob->instructions_size() >= total_code_size(), "good sizing");
617 this->compute_final_layout(&dest);
618 relocate_code_to(&dest);
619
620 // transfer comments from buffer to blob
621 dest_blob->set_comments(_comments);
622
623 // Done moving code bytes; were they the right size?
624 assert(round_to(dest.total_code_size(), oopSize) == dest_blob->instructions_size(), "sanity");
625
626 // Flush generated code
627 ICache::invalidate_range(dest_blob->instructions_begin(),
628 dest_blob->instructions_size());
629 }
630
631 // Move all my code into another code buffer.
632 // Consult applicable relocs to repair embedded addresses.
633 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
634 DEBUG_ONLY(address dest_end = dest->_total_start + dest->_total_size);
635 for (int n = 0; n < (int)SECT_LIMIT; n++) {
636 // pull code out of each section
637 const CodeSection* cs = code_section(n);
638 if (cs->is_empty()) continue; // skip trivial section
639 CodeSection* dest_cs = dest->code_section(n);
640 assert(cs->size() == dest_cs->size(), "sanity");
641 csize_t usize = dest_cs->size();
642 csize_t wsize = align_size_up(usize, HeapWordSize);
643 assert(dest_cs->start() + wsize <= dest_end, "no overflow");
644 // Copy the code as aligned machine words.
645 // This may also include an uninitialized partial word at the end.
646 Copy::disjoint_words((HeapWord*)cs->start(),
647 (HeapWord*)dest_cs->start(),
648 wsize / HeapWordSize);
649
650 if (dest->blob() == NULL) {
651 // Destination is a final resting place, not just another buffer.
652 // Normalize uninitialized bytes in the final padding.
653 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
654 Assembler::code_fill_byte());
655 }
656
657 assert(cs->locs_start() != (relocInfo*)badAddress,
658 "this section carries no reloc storage, but reloc was attempted");
659
660 // Make the new code copy use the old copy's relocations:
661 dest_cs->initialize_locs_from(cs);
662
663 { // Repair the pc relative information in the code after the move
664 RelocIterator iter(dest_cs);
665 while (iter.next()) {
666 iter.reloc()->fix_relocation_after_move(this, dest);
667 }
668 }
669 }
670 }
671
672 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
673 csize_t amount,
674 csize_t* new_capacity) {
675 csize_t new_total_cap = 0;
676
677 int prev_n = -1;
678 for (int n = 0; n < (int)SECT_LIMIT; n++) {
679 const CodeSection* sect = code_section(n);
680
681 if (!sect->is_empty()) {
682 // Compute initial padding; assign it to the previous non-empty guy.
683 // Cf. compute_final_layout.
684 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
685 if (padding != 0) {
686 new_total_cap += padding;
687 assert(prev_n >= 0, "sanity");
688 new_capacity[prev_n] += padding;
689 }
690 prev_n = n;
691 }
692
693 csize_t exp = sect->size(); // 100% increase
694 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase
695 if (sect == which_cs) {
696 if (exp < amount) exp = amount;
697 if (StressCodeBuffers) exp = amount; // expand only slightly
698 } else if (n == SECT_INSTS) {
699 // scale down inst increases to a more modest 25%
700 exp = 4*K + ((exp - 4*K) >> 2);
701 if (StressCodeBuffers) exp = amount / 2; // expand only slightly
702 } else if (sect->is_empty()) {
703 // do not grow an empty secondary section
704 exp = 0;
705 }
706 // Allow for inter-section slop:
707 exp += CodeSection::end_slop();
708 csize_t new_cap = sect->size() + exp;
709 if (new_cap < sect->capacity()) {
710 // No need to expand after all.
711 new_cap = sect->capacity();
712 }
713 new_capacity[n] = new_cap;
714 new_total_cap += new_cap;
715 }
716
717 return new_total_cap;
718 }
719
720 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
721 #ifndef PRODUCT
722 if (PrintNMethods && (WizardMode || Verbose)) {
723 tty->print("expanding CodeBuffer:");
724 this->print();
725 }
726
727 if (StressCodeBuffers && blob() != NULL) {
728 static int expand_count = 0;
729 if (expand_count >= 0) expand_count += 1;
730 if (expand_count > 100 && is_power_of_2(expand_count)) {
731 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
732 // simulate an occasional allocation failure:
733 free_blob();
734 }
735 }
736 #endif //PRODUCT
737
738 // Resizing must be allowed
739 {
740 if (blob() == NULL) return; // caller must check for blob == NULL
741 for (int n = 0; n < (int)SECT_LIMIT; n++) {
742 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen");
743 }
744 }
745
746 // Figure new capacity for each section.
747 csize_t new_capacity[SECT_LIMIT];
748 csize_t new_total_cap
749 = figure_expanded_capacities(which_cs, amount, new_capacity);
750
751 // Create a new (temporary) code buffer to hold all the new data
752 CodeBuffer cb(name(), new_total_cap, 0);
753 if (cb.blob() == NULL) {
754 // Failed to allocate in code cache.
755 free_blob();
756 return;
757 }
758
759 // Create an old code buffer to remember which addresses used to go where.
760 // This will be useful when we do final assembly into the code cache,
761 // because we will need to know how to warp any internal address that
762 // has been created at any time in this CodeBuffer's past.
763 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
764 bxp->take_over_code_from(this); // remember the old undersized blob
765 DEBUG_ONLY(this->_blob = NULL); // silence a later assert
766 bxp->_before_expand = this->_before_expand;
767 this->_before_expand = bxp;
768
769 // Give each section its required (expanded) capacity.
770 for (int n = (int)SECT_LIMIT-1; n >= SECT_INSTS; n--) {
771 CodeSection* cb_sect = cb.code_section(n);
772 CodeSection* this_sect = code_section(n);
773 if (new_capacity[n] == 0) continue; // already nulled out
774 if (n > SECT_INSTS) {
775 cb.initialize_section_size(cb_sect, new_capacity[n]);
776 }
777 assert(cb_sect->capacity() >= new_capacity[n], "big enough");
778 address cb_start = cb_sect->start();
779 cb_sect->set_end(cb_start + this_sect->size());
780 if (this_sect->mark() == NULL) {
781 cb_sect->clear_mark();
782 } else {
783 cb_sect->set_mark(cb_start + this_sect->mark_off());
784 }
785 }
786
787 // Move all the code and relocations to the new blob:
788 relocate_code_to(&cb);
789
790 // Copy the temporary code buffer into the current code buffer.
791 // Basically, do {*this = cb}, except for some control information.
792 this->take_over_code_from(&cb);
793 cb.set_blob(NULL);
794
795 // Zap the old code buffer contents, to avoid mistakenly using them.
796 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
797 badCodeHeapFreeVal));
798
799 _decode_begin = NULL; // sanity
800
801 // Make certain that the new sections are all snugly inside the new blob.
802 assert(verify_section_allocation(), "expanded allocation is ship-shape");
803
804 #ifndef PRODUCT
805 if (PrintNMethods && (WizardMode || Verbose)) {
806 tty->print("expanded CodeBuffer:");
807 this->print();
808 }
809 #endif //PRODUCT
810 }
811
812 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
813 // Must already have disposed of the old blob somehow.
814 assert(blob() == NULL, "must be empty");
815 #ifdef ASSERT
816
817 #endif
818 // Take the new blob away from cb.
819 set_blob(cb->blob());
820 // Take over all the section pointers.
821 for (int n = 0; n < (int)SECT_LIMIT; n++) {
822 CodeSection* cb_sect = cb->code_section(n);
823 CodeSection* this_sect = code_section(n);
824 this_sect->take_over_code_from(cb_sect);
825 }
826 _overflow_arena = cb->_overflow_arena;
827 // Make sure the old cb won't try to use it or free it.
828 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
829 }
830
831 #ifdef ASSERT
832 bool CodeBuffer::verify_section_allocation() {
833 address tstart = _total_start;
834 if (tstart == badAddress) return true; // smashed by set_blob(NULL)
835 address tend = tstart + _total_size;
836 if (_blob != NULL) {
837 assert(tstart >= _blob->instructions_begin(), "sanity");
838 assert(tend <= _blob->instructions_end(), "sanity");
839 }
840 address tcheck = tstart; // advancing pointer to verify disjointness
841 for (int n = 0; n < (int)SECT_LIMIT; n++) {
842 CodeSection* sect = code_section(n);
843 if (!sect->is_allocated()) continue;
844 assert(sect->start() >= tcheck, "sanity");
845 tcheck = sect->start();
846 assert((intptr_t)tcheck % sect->alignment() == 0
847 || sect->is_empty() || _blob == NULL,
848 "start is aligned");
849 assert(sect->end() >= tcheck, "sanity");
850 assert(sect->end() <= tend, "sanity");
851 }
852 return true;
853 }
854 #endif //ASSERT
855
856 #ifndef PRODUCT
857
858 void CodeSection::dump() {
859 address ptr = start();
860 for (csize_t step; ptr < end(); ptr += step) {
861 step = end() - ptr;
862 if (step > jintSize * 4) step = jintSize * 4;
863 tty->print(PTR_FORMAT ": ", ptr);
864 while (step > 0) {
865 tty->print(" " PTR32_FORMAT, *(jint*)ptr);
866 ptr += jintSize;
867 }
868 tty->cr();
869 }
870 }
871
872
873 void CodeSection::decode() {
874 Disassembler::decode(start(), end());
875 }
876
877
878 void CodeBuffer::block_comment(intptr_t offset, const char * comment) {
879 _comments.add_comment(offset, comment);
880 }
881
882
883 class CodeComment: public CHeapObj {
884 private:
885 friend class CodeComments;
886 intptr_t _offset;
887 const char * _comment;
888 CodeComment* _next;
889
890 ~CodeComment() {
891 assert(_next == NULL, "wrong interface for freeing list");
892 os::free((void*)_comment);
893 }
894
895 public:
896 CodeComment(intptr_t offset, const char * comment) {
897 _offset = offset;
898 _comment = os::strdup(comment);
899 _next = NULL;
900 }
901
902 intptr_t offset() const { return _offset; }
903 const char * comment() const { return _comment; }
904 CodeComment* next() { return _next; }
905
906 void set_next(CodeComment* next) { _next = next; }
907
908 CodeComment* find(intptr_t offset) {
909 CodeComment* a = this;
910 while (a != NULL && a->_offset != offset) {
911 a = a->_next;
912 }
913 return a;
914 }
915 };
916
917
918 void CodeComments::add_comment(intptr_t offset, const char * comment) {
919 CodeComment* c = new CodeComment(offset, comment);
920 CodeComment* insert = NULL;
921 if (_comments != NULL) {
922 CodeComment* c = _comments->find(offset);
923 insert = c;
924 while (c && c->offset() == offset) {
925 insert = c;
926 c = c->next();
927 }
928 }
929 if (insert) {
930 // insert after comments with same offset
931 c->set_next(insert->next());
932 insert->set_next(c);
933 } else {
934 c->set_next(_comments);
935 _comments = c;
936 }
937 }
938
939
940 void CodeComments::assign(CodeComments& other) {
941 assert(_comments == NULL, "don't overwrite old value");
942 _comments = other._comments;
943 }
944
945
946 void CodeComments::print_block_comment(outputStream* stream, intptr_t offset) {
947 if (_comments != NULL) {
948 CodeComment* c = _comments->find(offset);
949 while (c && c->offset() == offset) {
950 stream->print(" ;; ");
951 stream->print_cr(c->comment());
952 c = c->next();
953 }
954 }
955 }
956
957
958 void CodeComments::free() {
959 CodeComment* n = _comments;
960 while (n) {
961 // unlink the node from the list saving a pointer to the next
962 CodeComment* p = n->_next;
963 n->_next = NULL;
964 delete n;
965 n = p;
966 }
967 _comments = NULL;
968 }
969
970
971
972 void CodeBuffer::decode() {
973 Disassembler::decode(decode_begin(), code_end());
974 _decode_begin = code_end();
975 }
976
977
978 void CodeBuffer::skip_decode() {
979 _decode_begin = code_end();
980 }
981
982
983 void CodeBuffer::decode_all() {
984 for (int n = 0; n < (int)SECT_LIMIT; n++) {
985 // dump contents of each section
986 CodeSection* cs = code_section(n);
987 tty->print_cr("! %s:", code_section_name(n));
988 if (cs != consts())
989 cs->decode();
990 else
991 cs->dump();
992 }
993 }
994
995
996 void CodeSection::print(const char* name) {
997 csize_t locs_size = locs_end() - locs_start();
998 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s",
999 name, start(), end(), limit(), size(), capacity(),
1000 is_frozen()? " [frozen]": "");
1001 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1002 name, locs_start(), locs_end(), locs_limit(), locs_size, locs_capacity(), locs_point_off());
1003 if (PrintRelocations) {
1004 RelocIterator iter(this);
1005 iter.print();
1006 }
1007 }
1008
1009 void CodeBuffer::print() {
1010 if (this == NULL) {
1011 tty->print_cr("NULL CodeBuffer pointer");
1012 return;
1013 }
1014
1015 tty->print_cr("CodeBuffer:");
1016 for (int n = 0; n < (int)SECT_LIMIT; n++) {
1017 // print each section
1018 CodeSection* cs = code_section(n);
1019 cs->print(code_section_name(n));
1020 }
1021 }
1022
1023 #endif // PRODUCT