Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/runtime/relocator.cpp

src/share/vm/runtime/relocator.cpp

changeset 0
f90c822e73f8
child 6876
710a3c8b516e
equal deleted inserted replaced
-1:000000000000 0:f90c822e73f8
1 /*
2 * Copyright (c) 1997, 2012, 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 "classfile/stackMapTableFormat.hpp"
27 #include "interpreter/bytecodes.hpp"
28 #include "memory/metadataFactory.hpp"
29 #include "memory/oopFactory.hpp"
30 #include "memory/universe.inline.hpp"
31 #include "oops/oop.inline.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "runtime/relocator.hpp"
34
35 #define MAX_METHOD_LENGTH 65535
36
37 #define MAX_SHORT ((1 << 15) - 1)
38 #define MIN_SHORT (- (1 << 15))
39
40 // Encapsulates a code change request. There are 3 types.
41 // General instruction, jump instruction, and table/lookup switches
42 //
43 class ChangeItem : public ResourceObj {
44 int _bci;
45 public:
46 ChangeItem(int bci) { _bci = bci; }
47 virtual bool handle_code_change(Relocator *r) = 0;
48
49 // type info
50 virtual bool is_widen() { return false; }
51 virtual bool is_jump_widen() { return false; }
52 virtual bool is_switch_pad() { return false; }
53
54 // accessors
55 int bci() { return _bci; }
56 void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } }
57
58 virtual bool adjust(int bci, int delta) { return false; }
59
60 // debug
61 virtual void print() = 0;
62 };
63
64 class ChangeWiden : public ChangeItem {
65 int _new_ilen; // New length of instruction at bci
66 u_char* _inst_buffer; // New bytecodes
67 public:
68 ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) {
69 _new_ilen = new_ilen;
70 _inst_buffer = inst_buffer;
71 }
72
73 // Callback to do instruction
74 bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); };
75
76 bool is_widen() { return true; }
77
78 void print() { tty->print_cr("ChangeWiden. bci: %d New_ilen: %d", bci(), _new_ilen); }
79 };
80
81 class ChangeJumpWiden : public ChangeItem {
82 int _delta; // New length of instruction at bci
83 public:
84 ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; }
85
86 // Callback to do instruction
87 bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); };
88
89 bool is_jump_widen() { return true; }
90
91 // If the bci matches, adjust the delta in the change jump request.
92 bool adjust(int jump_bci, int delta) {
93 if (bci() == jump_bci) {
94 if (_delta > 0)
95 _delta += delta;
96 else
97 _delta -= delta;
98 return true;
99 }
100 return false;
101 }
102
103 void print() { tty->print_cr("ChangeJumpWiden. bci: %d Delta: %d", bci(), _delta); }
104 };
105
106 class ChangeSwitchPad : public ChangeItem {
107 int _padding;
108 bool _is_lookup_switch;
109 public:
110 ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) {
111 _padding = padding;
112 _is_lookup_switch = is_lookup_switch;
113 }
114
115 // Callback to do instruction
116 bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); };
117
118 bool is_switch_pad() { return true; }
119 int padding() { return _padding; }
120 bool is_lookup_switch() { return _is_lookup_switch; }
121
122 void print() { tty->print_cr("ChangeSwitchPad. bci: %d Padding: %d IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); }
123 };
124
125 //-----------------------------------------------------------------------------------------------------------
126 // Relocator code
127
128 Relocator::Relocator(methodHandle m, RelocatorListener* listener) {
129 set_method(m);
130 set_code_length(method()->code_size());
131 set_code_array(NULL);
132 // Allocate code array and copy bytecodes
133 if (!expand_code_array(0)) {
134 // Should have at least MAX_METHOD_LENGTH available or the verifier
135 // would have failed.
136 ShouldNotReachHere();
137 }
138 set_compressed_line_number_table(NULL);
139 set_compressed_line_number_table_size(0);
140 _listener = listener;
141 }
142
143 // size is the new size of the instruction at bci. Hence, if size is less than the current
144 // instruction sice, we will shrink the code.
145 methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) {
146 _changes = new GrowableArray<ChangeItem*> (10);
147 _changes->push(new ChangeWiden(bci, size, inst_buffer));
148
149 if (TraceRelocator) {
150 tty->print_cr("Space at: %d Size: %d", bci, size);
151 _method->print();
152 _method->print_codes();
153 tty->print_cr("-------------------------------------------------");
154 }
155
156 if (!handle_code_changes()) return methodHandle();
157
158 // Construct the new method
159 methodHandle new_method = Method::clone_with_new_data(method(),
160 code_array(), code_length(),
161 compressed_line_number_table(),
162 compressed_line_number_table_size(),
163 CHECK_(methodHandle()));
164
165 // Deallocate the old Method* from metadata
166 ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
167 loader_data->add_to_deallocate_list(method()());
168
169 set_method(new_method);
170
171 if (TraceRelocator) {
172 tty->print_cr("-------------------------------------------------");
173 tty->print_cr("new method");
174 _method->print_codes();
175 }
176
177 return new_method;
178 }
179
180
181 bool Relocator::handle_code_changes() {
182 assert(_changes != NULL, "changes vector must be initialized");
183
184 while (!_changes->is_empty()) {
185 // Inv: everything is aligned.
186 ChangeItem* ci = _changes->first();
187
188 if (TraceRelocator) {
189 ci->print();
190 }
191
192 // Execute operation
193 if (!ci->handle_code_change(this)) return false;
194
195 // Shuffel items up
196 for (int index = 1; index < _changes->length(); index++) {
197 _changes->at_put(index-1, _changes->at(index));
198 }
199 _changes->pop();
200 }
201 return true;
202 }
203
204
205 bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) {
206 switch (bc) {
207 case Bytecodes::_tableswitch: return false;
208 case Bytecodes::_lookupswitch: // not rewritten on ia64
209 case Bytecodes::_fast_linearswitch: // rewritten _lookupswitch
210 case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch
211 default: ShouldNotReachHere();
212 }
213 return true; // dummy
214 }
215
216 // We need a special instruction size method, since lookupswitches and tableswitches might not be
217 // properly alligned during relocation
218 int Relocator::rc_instr_len(int bci) {
219 Bytecodes::Code bc= code_at(bci);
220 switch (bc) {
221 // In the case of switch instructions, see if we have the original
222 // padding recorded.
223 case Bytecodes::_tableswitch:
224 case Bytecodes::_lookupswitch:
225 case Bytecodes::_fast_linearswitch:
226 case Bytecodes::_fast_binaryswitch:
227 {
228 int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc));
229 if (pad == -1) {
230 return instruction_length_at(bci);
231 }
232 // Otherwise, depends on the switch type.
233 switch (bc) {
234 case Bytecodes::_tableswitch: {
235 int lo = int_at(bci + 1 + pad + 4 * 1);
236 int hi = int_at(bci + 1 + pad + 4 * 2);
237 int n = hi - lo + 1;
238 return 1 + pad + 4*(3 + n);
239 }
240 case Bytecodes::_lookupswitch:
241 case Bytecodes::_fast_linearswitch:
242 case Bytecodes::_fast_binaryswitch: {
243 int npairs = int_at(bci + 1 + pad + 4 * 1);
244 return 1 + pad + 4*(2 + 2*npairs);
245 }
246 default:
247 ShouldNotReachHere();
248 }
249 }
250 }
251 return instruction_length_at(bci);
252 }
253
254 // If a change item is recorded for "pc", with type "ct", returns the
255 // associated padding, else -1.
256 int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) {
257 for (int k = 0; k < _changes->length(); k++) {
258 ChangeItem* ci = _changes->at(k);
259 if (ci->is_switch_pad()) {
260 ChangeSwitchPad* csp = (ChangeSwitchPad*)ci;
261 if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) {
262 return csp->padding();
263 }
264 }
265 }
266 return -1;
267 }
268
269
270 // Push a ChangeJumpWiden if it doesn't already exist on the work queue,
271 // otherwise adjust the item already there by delta. The calculation for
272 // new_delta is wrong for this because it uses the offset stored in the
273 // code stream itself which wasn't fixed when item was pushed on the work queue.
274 void Relocator::push_jump_widen(int bci, int delta, int new_delta) {
275 for (int j = 0; j < _changes->length(); j++) {
276 ChangeItem* ci = _changes->at(j);
277 if (ci->adjust(bci, delta)) return;
278 }
279 _changes->push(new ChangeJumpWiden(bci, new_delta));
280 }
281
282
283 // The current instruction of "c" is a jump; one of its offset starts
284 // at "offset" and is a short if "isShort" is "TRUE",
285 // and an integer otherwise. If the jump crosses "breakPC", change
286 // the span of the jump by "delta".
287 void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) {
288 int bci_delta = (is_short) ? short_at(offset) : int_at(offset);
289 int targ = bci + bci_delta;
290
291 if ((bci <= break_bci && targ > break_bci) ||
292 (bci > break_bci && targ <= break_bci)) {
293 int new_delta;
294 if (bci_delta > 0)
295 new_delta = bci_delta + delta;
296 else
297 new_delta = bci_delta - delta;
298
299 if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) {
300 push_jump_widen(bci, delta, new_delta);
301 } else if (is_short) {
302 short_at_put(offset, new_delta);
303 } else {
304 int_at_put(offset, new_delta);
305 }
306 }
307 }
308
309
310 // Changes all jumps crossing "break_bci" by "delta". May enqueue things
311 // on "rc->changes"
312 void Relocator::change_jumps(int break_bci, int delta) {
313 int bci = 0;
314 Bytecodes::Code bc;
315 // Now, adjust any affected instructions.
316 while (bci < code_length()) {
317 switch (bc= code_at(bci)) {
318 case Bytecodes::_ifeq:
319 case Bytecodes::_ifne:
320 case Bytecodes::_iflt:
321 case Bytecodes::_ifge:
322 case Bytecodes::_ifgt:
323 case Bytecodes::_ifle:
324 case Bytecodes::_if_icmpeq:
325 case Bytecodes::_if_icmpne:
326 case Bytecodes::_if_icmplt:
327 case Bytecodes::_if_icmpge:
328 case Bytecodes::_if_icmpgt:
329 case Bytecodes::_if_icmple:
330 case Bytecodes::_if_acmpeq:
331 case Bytecodes::_if_acmpne:
332 case Bytecodes::_ifnull:
333 case Bytecodes::_ifnonnull:
334 case Bytecodes::_goto:
335 case Bytecodes::_jsr:
336 change_jump(bci, bci+1, true, break_bci, delta);
337 break;
338 case Bytecodes::_goto_w:
339 case Bytecodes::_jsr_w:
340 change_jump(bci, bci+1, false, break_bci, delta);
341 break;
342 case Bytecodes::_tableswitch:
343 case Bytecodes::_lookupswitch:
344 case Bytecodes::_fast_linearswitch:
345 case Bytecodes::_fast_binaryswitch: {
346 int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch));
347 int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1);
348 if (bci > break_bci) {
349 int new_bci = bci + delta;
350 int newPad = align(new_bci+1) - (new_bci+1);
351 // Do we need to check the padding?
352 if (newPad != oldPad) {
353 if (recPad == -1) {
354 _changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch)));
355 }
356 }
357 }
358
359 // Then the rest, which depend on the kind of switch.
360 switch (bc) {
361 case Bytecodes::_tableswitch: {
362 change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
363 // We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct.
364 int lo = int_at(bci + 1 + oldPad + 4 * 1);
365 int hi = int_at(bci + 1 + oldPad + 4 * 2);
366 int n = hi - lo + 1;
367 for (int k = 0; k < n; k++) {
368 change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta);
369 }
370 // Special next-bci calculation here...
371 bci += 1 + oldPad + (n+3)*4;
372 continue;
373 }
374 case Bytecodes::_lookupswitch:
375 case Bytecodes::_fast_linearswitch:
376 case Bytecodes::_fast_binaryswitch: {
377 change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
378 // We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct.
379 int npairs = int_at(bci + 1 + oldPad + 4 * 1);
380 for (int k = 0; k < npairs; k++) {
381 change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta);
382 }
383 /* Special next-bci calculation here... */
384 bci += 1 + oldPad + (2 + (npairs*2))*4;
385 continue;
386 }
387 default:
388 ShouldNotReachHere();
389 }
390 }
391 default:
392 break;
393 }
394 bci += rc_instr_len(bci);
395 }
396 }
397
398 // The width of instruction at "pc" is changing by "delta". Adjust the
399 // exception table, if any, of "rc->mb".
400 void Relocator::adjust_exception_table(int bci, int delta) {
401 ExceptionTable table(_method());
402 for (int index = 0; index < table.length(); index ++) {
403 if (table.start_pc(index) > bci) {
404 table.set_start_pc(index, table.start_pc(index) + delta);
405 table.set_end_pc(index, table.end_pc(index) + delta);
406 } else if (bci < table.end_pc(index)) {
407 table.set_end_pc(index, table.end_pc(index) + delta);
408 }
409 if (table.handler_pc(index) > bci)
410 table.set_handler_pc(index, table.handler_pc(index) + delta);
411 }
412 }
413
414
415 // The width of instruction at "bci" is changing by "delta". Adjust the line number table.
416 void Relocator::adjust_line_no_table(int bci, int delta) {
417 if (method()->has_linenumber_table()) {
418 CompressedLineNumberReadStream reader(method()->compressed_linenumber_table());
419 CompressedLineNumberWriteStream writer(64); // plenty big for most line number tables
420 while (reader.read_pair()) {
421 int adjustment = (reader.bci() > bci) ? delta : 0;
422 writer.write_pair(reader.bci() + adjustment, reader.line());
423 }
424 writer.write_terminator();
425 set_compressed_line_number_table(writer.buffer());
426 set_compressed_line_number_table_size(writer.position());
427 }
428 }
429
430
431 // The width of instruction at "bci" is changing by "delta". Adjust the local variable table.
432 void Relocator::adjust_local_var_table(int bci, int delta) {
433 int localvariable_table_length = method()->localvariable_table_length();
434 if (localvariable_table_length > 0) {
435 LocalVariableTableElement* table = method()->localvariable_table_start();
436 for (int i = 0; i < localvariable_table_length; i++) {
437 u2 current_bci = table[i].start_bci;
438 if (current_bci > bci) {
439 table[i].start_bci = current_bci + delta;
440 } else {
441 u2 current_length = table[i].length;
442 if (current_bci + current_length > bci) {
443 table[i].length = current_length + delta;
444 }
445 }
446 }
447 }
448 }
449
450 // Create a new array, copying the src array but adding a hole at
451 // the specified location
452 static Array<u1>* insert_hole_at(ClassLoaderData* loader_data,
453 size_t where, int hole_sz, Array<u1>* src) {
454 Thread* THREAD = Thread::current();
455 Array<u1>* dst =
456 MetadataFactory::new_array<u1>(loader_data, src->length() + hole_sz, 0, CHECK_NULL);
457
458 address src_addr = (address)src->adr_at(0);
459 address dst_addr = (address)dst->adr_at(0);
460
461 memcpy(dst_addr, src_addr, where);
462 memcpy(dst_addr + where + hole_sz,
463 src_addr + where, src->length() - where);
464 return dst;
465 }
466
467 // The width of instruction at "bci" is changing by "delta". Adjust the stack
468 // map frames.
469 void Relocator::adjust_stack_map_table(int bci, int delta) {
470 if (method()->has_stackmap_table()) {
471 Array<u1>* data = method()->stackmap_data();
472 // The data in the array is a classfile representation of the stackmap table
473 stack_map_table* sm_table =
474 stack_map_table::at((address)data->adr_at(0));
475
476 int count = sm_table->number_of_entries();
477 stack_map_frame* frame = sm_table->entries();
478 int bci_iter = -1;
479 bool offset_adjusted = false; // only need to adjust one offset
480
481 for (int i = 0; i < count; ++i) {
482 int offset_delta = frame->offset_delta();
483 bci_iter += offset_delta;
484
485 if (!offset_adjusted && bci_iter > bci) {
486 int new_offset_delta = offset_delta + delta;
487
488 if (frame->is_valid_offset(new_offset_delta)) {
489 frame->set_offset_delta(new_offset_delta);
490 } else {
491 assert(frame->is_same_frame() ||
492 frame->is_same_locals_1_stack_item_frame(),
493 "Frame must be one of the compressed forms");
494 // The new delta exceeds the capacity of the 'same_frame' or
495 // 'same_frame_1_stack_item_frame' frame types. We need to
496 // convert these frames to the extended versions, but the extended
497 // version is bigger and requires more room. So we allocate a
498 // new array and copy the data, being sure to leave u2-sized hole
499 // right after the 'frame_type' for the new offset field.
500 //
501 // We can safely ignore the reverse situation as a small delta
502 // can still be used in an extended version of the frame.
503
504 size_t frame_offset = (address)frame - (address)data->adr_at(0);
505
506 ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
507 Array<u1>* new_data = insert_hole_at(loader_data, frame_offset + 1, 2, data);
508 if (new_data == NULL) {
509 return; // out-of-memory?
510 }
511 // Deallocate old data
512 MetadataFactory::free_array<u1>(loader_data, data);
513 data = new_data;
514
515 address frame_addr = (address)(data->adr_at(0) + frame_offset);
516 frame = stack_map_frame::at(frame_addr);
517
518
519 // Now convert the frames in place
520 if (frame->is_same_frame()) {
521 same_frame_extended::create_at(frame_addr, new_offset_delta);
522 } else {
523 same_locals_1_stack_item_extended::create_at(
524 frame_addr, new_offset_delta, NULL);
525 // the verification_info_type should already be at the right spot
526 }
527 }
528 offset_adjusted = true; // needs to be done only once, since subsequent
529 // values are offsets from the current
530 }
531
532 // The stack map frame may contain verification types, if so we need to
533 // check and update any Uninitialized type's bci (no matter where it is).
534 int number_of_types = frame->number_of_types();
535 verification_type_info* types = frame->types();
536
537 for (int i = 0; i < number_of_types; ++i) {
538 if (types->is_uninitialized() && types->bci() > bci) {
539 types->set_bci(types->bci() + delta);
540 }
541 types = types->next();
542 }
543
544 // Full frame has stack values too
545 full_frame* ff = frame->as_full_frame();
546 if (ff != NULL) {
547 address eol = (address)types;
548 number_of_types = ff->stack_slots(eol);
549 types = ff->stack(eol);
550 for (int i = 0; i < number_of_types; ++i) {
551 if (types->is_uninitialized() && types->bci() > bci) {
552 types->set_bci(types->bci() + delta);
553 }
554 types = types->next();
555 }
556 }
557
558 frame = frame->next();
559 }
560
561 method()->set_stackmap_data(data); // in case it has changed
562 }
563 }
564
565
566 bool Relocator::expand_code_array(int delta) {
567 int length = MAX2(code_length() + delta, code_length() * (100+code_slop_pct()) / 100);
568
569 if (length > MAX_METHOD_LENGTH) {
570 if (delta == 0 && code_length() <= MAX_METHOD_LENGTH) {
571 length = MAX_METHOD_LENGTH;
572 } else {
573 return false;
574 }
575 }
576
577 unsigned char* new_code_array = NEW_RESOURCE_ARRAY(unsigned char, length);
578 if (!new_code_array) return false;
579
580 // Expanding current array
581 if (code_array() != NULL) {
582 memcpy(new_code_array, code_array(), code_length());
583 } else {
584 // Initial copy. Copy directly from Method*
585 memcpy(new_code_array, method()->code_base(), code_length());
586 }
587
588 set_code_array(new_code_array);
589 set_code_array_length(length);
590
591 return true;
592 }
593
594
595 // The instruction at "bci", whose size is "ilen", is changing size by
596 // "delta". Reallocate, move code, recalculate jumps, and enqueue
597 // change items as necessary.
598 bool Relocator::relocate_code(int bci, int ilen, int delta) {
599 int next_bci = bci + ilen;
600 if (delta > 0 && code_length() + delta > code_array_length()) {
601 // Expand allocated code space, if necessary.
602 if (!expand_code_array(delta)) {
603 return false;
604 }
605 }
606
607 // We require 4-byte alignment of code arrays.
608 assert(((intptr_t)code_array() & 3) == 0, "check code alignment");
609 // Change jumps before doing the copying; this routine requires aligned switches.
610 change_jumps(bci, delta);
611
612 // In case we have shrunken a tableswitch/lookupswitch statement, we store the last
613 // bytes that get overwritten. We have to copy the bytes after the change_jumps method
614 // has been called, since it is likly to update last offset in a tableswitch/lookupswitch
615 if (delta < 0) {
616 assert(delta>=-3, "we cannot overwrite more than 3 bytes");
617 memcpy(_overwrite, addr_at(bci + ilen + delta), -delta);
618 }
619
620 memmove(addr_at(next_bci + delta), addr_at(next_bci), code_length() - next_bci);
621 set_code_length(code_length() + delta);
622 // Also adjust exception tables...
623 adjust_exception_table(bci, delta);
624 // Line number tables...
625 adjust_line_no_table(bci, delta);
626 // And local variable table...
627 adjust_local_var_table(bci, delta);
628
629 // Adjust stack maps
630 adjust_stack_map_table(bci, delta);
631
632 // Relocate the pending change stack...
633 for (int j = 0; j < _changes->length(); j++) {
634 ChangeItem* ci = _changes->at(j);
635 ci->relocate(bci, delta);
636 }
637
638 // Notify any listeners about code relocation
639 notify(bci, delta, code_length());
640
641 return true;
642 }
643
644 // relocate a general instruction. Called by ChangeWiden class
645 bool Relocator::handle_widen(int bci, int new_ilen, u_char inst_buffer[]) {
646 int ilen = rc_instr_len(bci);
647 if (!relocate_code(bci, ilen, new_ilen - ilen))
648 return false;
649
650 // Insert new bytecode(s)
651 for(int k = 0; k < new_ilen; k++) {
652 code_at_put(bci + k, (Bytecodes::Code)inst_buffer[k]);
653 }
654
655 return true;
656 }
657
658 // handle jump_widen instruction. Called be ChangeJumpWiden class
659 bool Relocator::handle_jump_widen(int bci, int delta) {
660 int ilen = rc_instr_len(bci);
661
662 Bytecodes::Code bc = code_at(bci);
663 switch (bc) {
664 case Bytecodes::_ifeq:
665 case Bytecodes::_ifne:
666 case Bytecodes::_iflt:
667 case Bytecodes::_ifge:
668 case Bytecodes::_ifgt:
669 case Bytecodes::_ifle:
670 case Bytecodes::_if_icmpeq:
671 case Bytecodes::_if_icmpne:
672 case Bytecodes::_if_icmplt:
673 case Bytecodes::_if_icmpge:
674 case Bytecodes::_if_icmpgt:
675 case Bytecodes::_if_icmple:
676 case Bytecodes::_if_acmpeq:
677 case Bytecodes::_if_acmpne:
678 case Bytecodes::_ifnull:
679 case Bytecodes::_ifnonnull: {
680 const int goto_length = Bytecodes::length_for(Bytecodes::_goto);
681
682 // If 'if' points to the next bytecode after goto, it's already handled.
683 // it shouldn't be.
684 assert (short_at(bci+1) != ilen+goto_length, "if relocation already handled");
685 assert(ilen == 3, "check length");
686
687 // Convert to 0 if <cond> goto 6
688 // 3 _goto 11
689 // 6 _goto_w <wide delta offset>
690 // 11 <else code>
691 const int goto_w_length = Bytecodes::length_for(Bytecodes::_goto_w);
692 const int add_bci = goto_length + goto_w_length;
693
694 if (!relocate_code(bci, 3, /*delta*/add_bci)) return false;
695
696 // if bytecode points to goto_w instruction
697 short_at_put(bci + 1, ilen + goto_length);
698
699 int cbci = bci + ilen;
700 // goto around
701 code_at_put(cbci, Bytecodes::_goto);
702 short_at_put(cbci + 1, add_bci);
703 // goto_w <wide delta>
704 cbci = cbci + goto_length;
705 code_at_put(cbci, Bytecodes::_goto_w);
706 if (delta > 0) {
707 delta += 2; // goto_w is 2 bytes more than "if" code
708 } else {
709 delta -= ilen+goto_length; // branch starts at goto_w offset
710 }
711 int_at_put(cbci + 1, delta);
712 break;
713
714 }
715 case Bytecodes::_goto:
716 case Bytecodes::_jsr:
717 assert(ilen == 3, "check length");
718
719 if (!relocate_code(bci, 3, 2)) return false;
720 if (bc == Bytecodes::_goto)
721 code_at_put(bci, Bytecodes::_goto_w);
722 else
723 code_at_put(bci, Bytecodes::_jsr_w);
724
725 // If it's a forward jump, add 2 for the widening.
726 if (delta > 0) delta += 2;
727 int_at_put(bci + 1, delta);
728 break;
729
730 default: ShouldNotReachHere();
731 }
732
733 return true;
734 }
735
736 // handle lookup/table switch instructions. Called be ChangeSwitchPad class
737 bool Relocator::handle_switch_pad(int bci, int old_pad, bool is_lookup_switch) {
738 int ilen = rc_instr_len(bci);
739 int new_pad = align(bci+1) - (bci+1);
740 int pad_delta = new_pad - old_pad;
741 if (pad_delta != 0) {
742 int len;
743 if (!is_lookup_switch) {
744 int low = int_at(bci+1+old_pad+4);
745 int high = int_at(bci+1+old_pad+8);
746 len = high-low+1 + 3; // 3 for default, hi, lo.
747 } else {
748 int npairs = int_at(bci+1+old_pad+4);
749 len = npairs*2 + 2; // 2 for default, npairs.
750 }
751 // Because "relocateCode" does a "changeJumps" loop,
752 // which parses instructions to determine their length,
753 // we need to call that before messing with the current
754 // instruction. Since it may also overwrite the current
755 // instruction when moving down, remember the possibly
756 // overwritten part.
757
758 // Move the code following the instruction...
759 if (!relocate_code(bci, ilen, pad_delta)) return false;
760
761 if (pad_delta < 0) {
762 // Move the shrunken instruction down.
763 memmove(addr_at(bci + 1 + new_pad),
764 addr_at(bci + 1 + old_pad),
765 len * 4 + pad_delta);
766 memmove(addr_at(bci + 1 + new_pad + len*4 + pad_delta),
767 _overwrite, -pad_delta);
768 } else {
769 assert(pad_delta > 0, "check");
770 // Move the expanded instruction up.
771 memmove(addr_at(bci +1 + new_pad),
772 addr_at(bci +1 + old_pad),
773 len * 4);
774 memset(addr_at(bci + 1), 0, new_pad); // pad must be 0
775 }
776 }
777 return true;
778 }

Mercurial Repository: jdk8-mips64-public/hotspot

mercurial