Mercurial > hg > graal-compiler
annotate src/share/vm/runtime/relocator.cpp @ 1646:8d5934a77f10
6968385: malformed xml in sweeper logging
Reviewed-by: kvn
author | never |
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date | Mon, 12 Jul 2010 22:27:18 -0700 |
parents | c18cbe5936b8 |
children | a4c7fe54bf3f |
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0 | 1 /* |
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2 * Copyright (c) 1997, 2005, Oracle and/or its affiliates. All rights reserved. |
0 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 # include "incls/_precompiled.incl" | |
26 # include "incls/_relocator.cpp.incl" | |
27 | |
28 #define MAX_METHOD_LENGTH 65535 | |
29 | |
30 #define MAX_SHORT ((1 << 15) - 1) | |
31 #define MIN_SHORT (- (1 << 15)) | |
32 | |
33 // Encapsulates a code change request. There are 3 types. | |
34 // General instruction, jump instruction, and table/lookup switches | |
35 // | |
36 class ChangeItem : public ResourceObj { | |
37 int _bci; | |
38 public: | |
39 ChangeItem(int bci) { _bci = bci; } | |
40 virtual bool handle_code_change(Relocator *r) = 0; | |
41 | |
42 // type info | |
43 virtual bool is_widen() { return false; } | |
44 virtual bool is_jump_widen() { return false; } | |
45 virtual bool is_switch_pad() { return false; } | |
46 | |
47 // accessors | |
48 int bci() { return _bci; } | |
49 void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } } | |
50 | |
51 virtual bool adjust(int bci, int delta) { return false; } | |
52 | |
53 // debug | |
54 virtual void print() = 0; | |
55 }; | |
56 | |
57 class ChangeWiden : public ChangeItem { | |
58 int _new_ilen; // New length of instruction at bci | |
59 u_char* _inst_buffer; // New bytecodes | |
60 public: | |
61 ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) { | |
62 _new_ilen = new_ilen; | |
63 _inst_buffer = inst_buffer; | |
64 } | |
65 | |
66 // Callback to do instruction | |
67 bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); }; | |
68 | |
69 bool is_widen() { return true; } | |
70 | |
71 void print() { tty->print_cr("ChangeWiden. bci: %d New_ilen: %d", bci(), _new_ilen); } | |
72 }; | |
73 | |
74 class ChangeJumpWiden : public ChangeItem { | |
75 int _delta; // New length of instruction at bci | |
76 public: | |
77 ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; } | |
78 | |
79 // Callback to do instruction | |
80 bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); }; | |
81 | |
82 bool is_jump_widen() { return true; } | |
83 | |
84 // If the bci matches, adjust the delta in the change jump request. | |
85 bool adjust(int jump_bci, int delta) { | |
86 if (bci() == jump_bci) { | |
87 if (_delta > 0) | |
88 _delta += delta; | |
89 else | |
90 _delta -= delta; | |
91 return true; | |
92 } | |
93 return false; | |
94 } | |
95 | |
96 void print() { tty->print_cr("ChangeJumpWiden. bci: %d Delta: %d", bci(), _delta); } | |
97 }; | |
98 | |
99 class ChangeSwitchPad : public ChangeItem { | |
100 int _padding; | |
101 bool _is_lookup_switch; | |
102 public: | |
103 ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) { | |
104 _padding = padding; | |
105 _is_lookup_switch = is_lookup_switch; | |
106 } | |
107 | |
108 // Callback to do instruction | |
109 bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); }; | |
110 | |
111 bool is_switch_pad() { return true; } | |
112 int padding() { return _padding; } | |
113 bool is_lookup_switch() { return _is_lookup_switch; } | |
114 | |
115 void print() { tty->print_cr("ChangeSwitchPad. bci: %d Padding: %d IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); } | |
116 }; | |
117 | |
118 //----------------------------------------------------------------------------------------------------------- | |
119 // Relocator code | |
120 | |
121 Relocator::Relocator(methodHandle m, RelocatorListener* listener) { | |
122 set_method(m); | |
123 set_code_length(method()->code_size()); | |
124 set_code_array(NULL); | |
125 // Allocate code array and copy bytecodes | |
126 if (!expand_code_array(0)) { | |
127 // Should have at least MAX_METHOD_LENGTH available or the verifier | |
128 // would have failed. | |
129 ShouldNotReachHere(); | |
130 } | |
131 set_compressed_line_number_table(NULL); | |
132 set_compressed_line_number_table_size(0); | |
133 _listener = listener; | |
134 } | |
135 | |
136 // size is the new size of the instruction at bci. Hence, if size is less than the current | |
137 // instruction sice, we will shrink the code. | |
138 methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) { | |
139 _changes = new GrowableArray<ChangeItem*> (10); | |
140 _changes->push(new ChangeWiden(bci, size, inst_buffer)); | |
141 | |
142 if (TraceRelocator) { | |
143 tty->print_cr("Space at: %d Size: %d", bci, size); | |
144 _method->print(); | |
145 _method->print_codes(); | |
146 tty->print_cr("-------------------------------------------------"); | |
147 } | |
148 | |
149 if (!handle_code_changes()) return methodHandle(); | |
150 | |
151 // Construct the new method | |
152 methodHandle new_method = methodOopDesc::clone_with_new_data(method(), | |
153 code_array(), code_length(), | |
154 compressed_line_number_table(), | |
155 compressed_line_number_table_size(), | |
156 CHECK_(methodHandle())); | |
157 set_method(new_method); | |
158 | |
159 if (TraceRelocator) { | |
160 tty->print_cr("-------------------------------------------------"); | |
161 tty->print_cr("new method"); | |
162 _method->print_codes(); | |
163 } | |
164 | |
165 return new_method; | |
166 } | |
167 | |
168 | |
169 bool Relocator::handle_code_changes() { | |
170 assert(_changes != NULL, "changes vector must be initialized"); | |
171 | |
172 while (!_changes->is_empty()) { | |
173 // Inv: everything is aligned. | |
174 ChangeItem* ci = _changes->first(); | |
175 | |
176 if (TraceRelocator) { | |
177 ci->print(); | |
178 } | |
179 | |
180 // Execute operation | |
181 if (!ci->handle_code_change(this)) return false; | |
182 | |
183 // Shuffel items up | |
184 for (int index = 1; index < _changes->length(); index++) { | |
185 _changes->at_put(index-1, _changes->at(index)); | |
186 } | |
187 _changes->pop(); | |
188 } | |
189 return true; | |
190 } | |
191 | |
192 | |
193 bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) { | |
194 switch (bc) { | |
195 case Bytecodes::_tableswitch: return false; | |
196 case Bytecodes::_lookupswitch: // not rewritten on ia64 | |
197 case Bytecodes::_fast_linearswitch: // rewritten _lookupswitch | |
198 case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch | |
199 default: ShouldNotReachHere(); | |
200 } | |
201 return true; // dummy | |
202 } | |
203 | |
204 // We need a special instruction size method, since lookupswitches and tableswitches might not be | |
205 // properly alligned during relocation | |
206 int Relocator::rc_instr_len(int bci) { | |
207 Bytecodes::Code bc= code_at(bci); | |
208 switch (bc) { | |
209 // In the case of switch instructions, see if we have the original | |
210 // padding recorded. | |
211 case Bytecodes::_tableswitch: | |
212 case Bytecodes::_lookupswitch: | |
213 case Bytecodes::_fast_linearswitch: | |
214 case Bytecodes::_fast_binaryswitch: | |
215 { | |
216 int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc)); | |
217 if (pad == -1) { | |
218 return instruction_length_at(bci); | |
219 } | |
220 // Otherwise, depends on the switch type. | |
221 switch (bc) { | |
222 case Bytecodes::_tableswitch: { | |
223 int lo = int_at(bci + 1 + pad + 4 * 1); | |
224 int hi = int_at(bci + 1 + pad + 4 * 2); | |
225 int n = hi - lo + 1; | |
226 return 1 + pad + 4*(3 + n); | |
227 } | |
228 case Bytecodes::_lookupswitch: | |
229 case Bytecodes::_fast_linearswitch: | |
230 case Bytecodes::_fast_binaryswitch: { | |
231 int npairs = int_at(bci + 1 + pad + 4 * 1); | |
232 return 1 + pad + 4*(2 + 2*npairs); | |
233 } | |
234 default: | |
235 ShouldNotReachHere(); | |
236 } | |
237 } | |
238 } | |
239 return instruction_length_at(bci); | |
240 } | |
241 | |
242 // If a change item is recorded for "pc", with type "ct", returns the | |
243 // associated padding, else -1. | |
244 int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) { | |
245 for (int k = 0; k < _changes->length(); k++) { | |
246 ChangeItem* ci = _changes->at(k); | |
247 if (ci->is_switch_pad()) { | |
248 ChangeSwitchPad* csp = (ChangeSwitchPad*)ci; | |
249 if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) { | |
250 return csp->padding(); | |
251 } | |
252 } | |
253 } | |
254 return -1; | |
255 } | |
256 | |
257 | |
258 // Push a ChangeJumpWiden if it doesn't already exist on the work queue, | |
259 // otherwise adjust the item already there by delta. The calculation for | |
260 // new_delta is wrong for this because it uses the offset stored in the | |
261 // code stream itself which wasn't fixed when item was pushed on the work queue. | |
262 void Relocator::push_jump_widen(int bci, int delta, int new_delta) { | |
263 for (int j = 0; j < _changes->length(); j++) { | |
264 ChangeItem* ci = _changes->at(j); | |
265 if (ci->adjust(bci, delta)) return; | |
266 } | |
267 _changes->push(new ChangeJumpWiden(bci, new_delta)); | |
268 } | |
269 | |
270 | |
271 // The current instruction of "c" is a jump; one of its offset starts | |
272 // at "offset" and is a short if "isShort" is "TRUE", | |
273 // and an integer otherwise. If the jump crosses "breakPC", change | |
274 // the span of the jump by "delta". | |
275 void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) { | |
276 int bci_delta = (is_short) ? short_at(offset) : int_at(offset); | |
277 int targ = bci + bci_delta; | |
278 | |
279 if ((bci <= break_bci && targ > break_bci) || | |
280 (bci > break_bci && targ <= break_bci)) { | |
281 int new_delta; | |
282 if (bci_delta > 0) | |
283 new_delta = bci_delta + delta; | |
284 else | |
285 new_delta = bci_delta - delta; | |
286 | |
287 if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) { | |
288 push_jump_widen(bci, delta, new_delta); | |
289 } else if (is_short) { | |
290 short_at_put(offset, new_delta); | |
291 } else { | |
292 int_at_put(offset, new_delta); | |
293 } | |
294 } | |
295 } | |
296 | |
297 | |
298 // Changes all jumps crossing "break_bci" by "delta". May enqueue things | |
299 // on "rc->changes" | |
300 void Relocator::change_jumps(int break_bci, int delta) { | |
301 int bci = 0; | |
302 Bytecodes::Code bc; | |
303 // Now, adjust any affected instructions. | |
304 while (bci < code_length()) { | |
305 switch (bc= code_at(bci)) { | |
306 case Bytecodes::_ifeq: | |
307 case Bytecodes::_ifne: | |
308 case Bytecodes::_iflt: | |
309 case Bytecodes::_ifge: | |
310 case Bytecodes::_ifgt: | |
311 case Bytecodes::_ifle: | |
312 case Bytecodes::_if_icmpeq: | |
313 case Bytecodes::_if_icmpne: | |
314 case Bytecodes::_if_icmplt: | |
315 case Bytecodes::_if_icmpge: | |
316 case Bytecodes::_if_icmpgt: | |
317 case Bytecodes::_if_icmple: | |
318 case Bytecodes::_if_acmpeq: | |
319 case Bytecodes::_if_acmpne: | |
320 case Bytecodes::_ifnull: | |
321 case Bytecodes::_ifnonnull: | |
322 case Bytecodes::_goto: | |
323 case Bytecodes::_jsr: | |
324 change_jump(bci, bci+1, true, break_bci, delta); | |
325 break; | |
326 case Bytecodes::_goto_w: | |
327 case Bytecodes::_jsr_w: | |
328 change_jump(bci, bci+1, false, break_bci, delta); | |
329 break; | |
330 case Bytecodes::_tableswitch: | |
331 case Bytecodes::_lookupswitch: | |
332 case Bytecodes::_fast_linearswitch: | |
333 case Bytecodes::_fast_binaryswitch: { | |
334 int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch)); | |
335 int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1); | |
336 if (bci > break_bci) { | |
337 int new_bci = bci + delta; | |
338 int newPad = align(new_bci+1) - (new_bci+1); | |
339 // Do we need to check the padding? | |
340 if (newPad != oldPad) { | |
341 if (recPad == -1) { | |
342 _changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch))); | |
343 } | |
344 } | |
345 } | |
346 | |
347 // Then the rest, which depend on the kind of switch. | |
348 switch (bc) { | |
349 case Bytecodes::_tableswitch: { | |
350 change_jump(bci, bci +1 + oldPad, false, break_bci, delta); | |
351 // We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct. | |
352 int lo = int_at(bci + 1 + oldPad + 4 * 1); | |
353 int hi = int_at(bci + 1 + oldPad + 4 * 2); | |
354 int n = hi - lo + 1; | |
355 for (int k = 0; k < n; k++) { | |
356 change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta); | |
357 } | |
358 // Special next-bci calculation here... | |
359 bci += 1 + oldPad + (n+3)*4; | |
360 continue; | |
361 } | |
362 case Bytecodes::_lookupswitch: | |
363 case Bytecodes::_fast_linearswitch: | |
364 case Bytecodes::_fast_binaryswitch: { | |
365 change_jump(bci, bci +1 + oldPad, false, break_bci, delta); | |
366 // We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct. | |
367 int npairs = int_at(bci + 1 + oldPad + 4 * 1); | |
368 for (int k = 0; k < npairs; k++) { | |
369 change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta); | |
370 } | |
371 /* Special next-bci calculation here... */ | |
372 bci += 1 + oldPad + (2 + (npairs*2))*4; | |
373 continue; | |
374 } | |
375 default: | |
376 ShouldNotReachHere(); | |
377 } | |
378 } | |
379 default: | |
380 break; | |
381 } | |
382 bci += rc_instr_len(bci); | |
383 } | |
384 } | |
385 | |
386 // The width of instruction at "pc" is changing by "delta". Adjust the | |
387 // exception table, if any, of "rc->mb". | |
388 void Relocator::adjust_exception_table(int bci, int delta) { | |
389 typeArrayOop table = method()->exception_table(); | |
390 for (int index = 0; index < table->length(); index +=4) { | |
391 if (table->int_at(index) > bci) { | |
392 table->int_at_put(index+0, table->int_at(index+0) + delta); | |
393 table->int_at_put(index+1, table->int_at(index+1) + delta); | |
394 } else if (bci < table->int_at(index+1)) { | |
395 table->int_at_put(index+1, table->int_at(index+1) + delta); | |
396 } | |
397 if (table->int_at(index+2) > bci) | |
398 table->int_at_put(index+2, table->int_at(index+2) + delta); | |
399 } | |
400 } | |
401 | |
402 | |
403 // The width of instruction at "bci" is changing by "delta". Adjust the line number table. | |
404 void Relocator::adjust_line_no_table(int bci, int delta) { | |
405 if (method()->has_linenumber_table()) { | |
406 CompressedLineNumberReadStream reader(method()->compressed_linenumber_table()); | |
407 CompressedLineNumberWriteStream writer(64); // plenty big for most line number tables | |
408 while (reader.read_pair()) { | |
409 int adjustment = (reader.bci() > bci) ? delta : 0; | |
410 writer.write_pair(reader.bci() + adjustment, reader.line()); | |
411 } | |
412 writer.write_terminator(); | |
413 set_compressed_line_number_table(writer.buffer()); | |
414 set_compressed_line_number_table_size(writer.position()); | |
415 } | |
416 } | |
417 | |
418 | |
419 // The width of instruction at "bci" is changing by "delta". Adjust the local variable table. | |
420 void Relocator::adjust_local_var_table(int bci, int delta) { | |
421 int localvariable_table_length = method()->localvariable_table_length(); | |
422 if (localvariable_table_length > 0) { | |
423 LocalVariableTableElement* table = method()->localvariable_table_start(); | |
424 for (int i = 0; i < localvariable_table_length; i++) { | |
425 u2 current_bci = table[i].start_bci; | |
426 if (current_bci > bci) { | |
427 table[i].start_bci = current_bci + delta; | |
428 } else { | |
429 u2 current_length = table[i].length; | |
430 if (current_bci + current_length > bci) { | |
431 table[i].length = current_length + delta; | |
432 } | |
433 } | |
434 } | |
435 } | |
436 } | |
437 | |
438 | |
439 bool Relocator::expand_code_array(int delta) { | |
440 int length = MAX2(code_length() + delta, code_length() * (100+code_slop_pct()) / 100); | |
441 | |
442 if (length > MAX_METHOD_LENGTH) { | |
443 if (delta == 0 && code_length() <= MAX_METHOD_LENGTH) { | |
444 length = MAX_METHOD_LENGTH; | |
445 } else { | |
446 return false; | |
447 } | |
448 } | |
449 | |
450 unsigned char* new_code_array = NEW_RESOURCE_ARRAY(unsigned char, length); | |
451 if (!new_code_array) return false; | |
452 | |
453 // Expanding current array | |
454 if (code_array() != NULL) { | |
455 memcpy(new_code_array, code_array(), code_length()); | |
456 } else { | |
457 // Initial copy. Copy directly from methodOop | |
458 memcpy(new_code_array, method()->code_base(), code_length()); | |
459 } | |
460 | |
461 set_code_array(new_code_array); | |
462 set_code_array_length(length); | |
463 | |
464 return true; | |
465 } | |
466 | |
467 | |
468 // The instruction at "bci", whose size is "ilen", is changing size by | |
469 // "delta". Reallocate, move code, recalculate jumps, and enqueue | |
470 // change items as necessary. | |
471 bool Relocator::relocate_code(int bci, int ilen, int delta) { | |
472 int next_bci = bci + ilen; | |
473 if (delta > 0 && code_length() + delta > code_array_length()) { | |
474 // Expand allocated code space, if necessary. | |
475 if (!expand_code_array(delta)) { | |
476 return false; | |
477 } | |
478 } | |
479 | |
480 // We require 4-byte alignment of code arrays. | |
481 assert(((intptr_t)code_array() & 3) == 0, "check code alignment"); | |
482 // Change jumps before doing the copying; this routine requires aligned switches. | |
483 change_jumps(bci, delta); | |
484 | |
485 // In case we have shrunken a tableswitch/lookupswitch statement, we store the last | |
486 // bytes that get overwritten. We have to copy the bytes after the change_jumps method | |
487 // has been called, since it is likly to update last offset in a tableswitch/lookupswitch | |
488 if (delta < 0) { | |
489 assert(delta>=-3, "we cannot overwrite more than 3 bytes"); | |
490 memcpy(_overwrite, addr_at(bci + ilen + delta), -delta); | |
491 } | |
492 | |
493 memmove(addr_at(next_bci + delta), addr_at(next_bci), code_length() - next_bci); | |
494 set_code_length(code_length() + delta); | |
495 // Also adjust exception tables... | |
496 adjust_exception_table(bci, delta); | |
497 // Line number tables... | |
498 adjust_line_no_table(bci, delta); | |
499 // And local variable table... | |
500 adjust_local_var_table(bci, delta); | |
501 | |
502 // Relocate the pending change stack... | |
503 for (int j = 0; j < _changes->length(); j++) { | |
504 ChangeItem* ci = _changes->at(j); | |
505 ci->relocate(bci, delta); | |
506 } | |
507 | |
508 // Notify any listeners about code relocation | |
509 notify(bci, delta, code_length()); | |
510 | |
511 return true; | |
512 } | |
513 | |
514 // relocate a general instruction. Called by ChangeWiden class | |
515 bool Relocator::handle_widen(int bci, int new_ilen, u_char inst_buffer[]) { | |
516 int ilen = rc_instr_len(bci); | |
517 if (!relocate_code(bci, ilen, new_ilen - ilen)) | |
518 return false; | |
519 | |
520 // Insert new bytecode(s) | |
521 for(int k = 0; k < new_ilen; k++) { | |
522 code_at_put(bci + k, (Bytecodes::Code)inst_buffer[k]); | |
523 } | |
524 | |
525 return true; | |
526 } | |
527 | |
528 // handle jump_widen instruction. Called be ChangeJumpWiden class | |
529 bool Relocator::handle_jump_widen(int bci, int delta) { | |
530 int ilen = rc_instr_len(bci); | |
531 | |
532 Bytecodes::Code bc = code_at(bci); | |
533 switch (bc) { | |
534 case Bytecodes::_ifeq: | |
535 case Bytecodes::_ifne: | |
536 case Bytecodes::_iflt: | |
537 case Bytecodes::_ifge: | |
538 case Bytecodes::_ifgt: | |
539 case Bytecodes::_ifle: | |
540 case Bytecodes::_if_icmpeq: | |
541 case Bytecodes::_if_icmpne: | |
542 case Bytecodes::_if_icmplt: | |
543 case Bytecodes::_if_icmpge: | |
544 case Bytecodes::_if_icmpgt: | |
545 case Bytecodes::_if_icmple: | |
546 case Bytecodes::_if_acmpeq: | |
547 case Bytecodes::_if_acmpne: | |
548 case Bytecodes::_ifnull: | |
549 case Bytecodes::_ifnonnull: { | |
550 const int goto_length = Bytecodes::length_for(Bytecodes::_goto); | |
551 | |
552 // If 'if' points to the next bytecode after goto, it's already handled. | |
553 // it shouldn't be. | |
554 assert (short_at(bci+1) != ilen+goto_length, "if relocation already handled"); | |
555 assert(ilen == 3, "check length"); | |
556 | |
557 // Convert to 0 if <cond> goto 6 | |
558 // 3 _goto 11 | |
559 // 6 _goto_w <wide delta offset> | |
560 // 11 <else code> | |
561 const int goto_w_length = Bytecodes::length_for(Bytecodes::_goto_w); | |
562 const int add_bci = goto_length + goto_w_length; | |
563 | |
564 if (!relocate_code(bci, 3, /*delta*/add_bci)) return false; | |
565 | |
566 // if bytecode points to goto_w instruction | |
567 short_at_put(bci + 1, ilen + goto_length); | |
568 | |
569 int cbci = bci + ilen; | |
570 // goto around | |
571 code_at_put(cbci, Bytecodes::_goto); | |
572 short_at_put(cbci + 1, add_bci); | |
573 // goto_w <wide delta> | |
574 cbci = cbci + goto_length; | |
575 code_at_put(cbci, Bytecodes::_goto_w); | |
576 if (delta > 0) { | |
577 delta += 2; // goto_w is 2 bytes more than "if" code | |
578 } else { | |
579 delta -= ilen+goto_length; // branch starts at goto_w offset | |
580 } | |
581 int_at_put(cbci + 1, delta); | |
582 break; | |
583 | |
584 } | |
585 case Bytecodes::_goto: | |
586 case Bytecodes::_jsr: | |
587 assert(ilen == 3, "check length"); | |
588 | |
589 if (!relocate_code(bci, 3, 2)) return false; | |
590 if (bc == Bytecodes::_goto) | |
591 code_at_put(bci, Bytecodes::_goto_w); | |
592 else | |
593 code_at_put(bci, Bytecodes::_jsr_w); | |
594 | |
595 // If it's a forward jump, add 2 for the widening. | |
596 if (delta > 0) delta += 2; | |
597 int_at_put(bci + 1, delta); | |
598 break; | |
599 | |
600 default: ShouldNotReachHere(); | |
601 } | |
602 | |
603 return true; | |
604 } | |
605 | |
606 // handle lookup/table switch instructions. Called be ChangeSwitchPad class | |
607 bool Relocator::handle_switch_pad(int bci, int old_pad, bool is_lookup_switch) { | |
608 int ilen = rc_instr_len(bci); | |
609 int new_pad = align(bci+1) - (bci+1); | |
610 int pad_delta = new_pad - old_pad; | |
611 if (pad_delta != 0) { | |
612 int len; | |
613 if (!is_lookup_switch) { | |
614 int low = int_at(bci+1+old_pad+4); | |
615 int high = int_at(bci+1+old_pad+8); | |
616 len = high-low+1 + 3; // 3 for default, hi, lo. | |
617 } else { | |
618 int npairs = int_at(bci+1+old_pad+4); | |
619 len = npairs*2 + 2; // 2 for default, npairs. | |
620 } | |
621 // Because "relocateCode" does a "changeJumps" loop, | |
622 // which parses instructions to determine their length, | |
623 // we need to call that before messing with the current | |
624 // instruction. Since it may also overwrite the current | |
625 // instruction when moving down, remember the possibly | |
626 // overwritten part. | |
627 | |
628 // Move the code following the instruction... | |
629 if (!relocate_code(bci, ilen, pad_delta)) return false; | |
630 | |
631 if (pad_delta < 0) { | |
632 // Move the shrunken instruction down. | |
633 memmove(addr_at(bci + 1 + new_pad), | |
634 addr_at(bci + 1 + old_pad), | |
635 len * 4 + pad_delta); | |
636 memmove(addr_at(bci + 1 + new_pad + len*4 + pad_delta), | |
637 _overwrite, -pad_delta); | |
638 } else { | |
639 assert(pad_delta > 0, "check"); | |
640 // Move the expanded instruction up. | |
641 memmove(addr_at(bci +1 + new_pad), | |
642 addr_at(bci +1 + old_pad), | |
643 len * 4); | |
644 } | |
645 } | |
646 return true; | |
647 } |