1 /*
2 * Copyright (c) 1997, 2011, 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 #ifndef SHARE_VM_CODE_RELOCINFO_HPP
26 #define SHARE_VM_CODE_RELOCINFO_HPP
27
28 #include "memory/allocation.hpp"
29 #include "utilities/top.hpp"
30
31 // Types in this file:
32 // relocInfo
33 // One element of an array of halfwords encoding compressed relocations.
34 // Also, the source of relocation types (relocInfo::oop_type, ...).
35 // Relocation
36 // A flyweight object representing a single relocation.
37 // It is fully unpacked from the compressed relocation array.
38 // oop_Relocation, ... (subclasses of Relocation)
39 // The location of some type-specific operations (oop_addr, ...).
40 // Also, the source of relocation specs (oop_Relocation::spec, ...).
41 // RelocationHolder
42 // A ValueObj type which acts as a union holding a Relocation object.
43 // Represents a relocation spec passed into a CodeBuffer during assembly.
44 // RelocIterator
45 // A StackObj which iterates over the relocations associated with
46 // a range of code addresses. Can be used to operate a copy of code.
47 // PatchingRelocIterator
48 // Specialized subtype of RelocIterator which removes breakpoints
49 // temporarily during iteration, then restores them.
50 // BoundRelocation
51 // An _internal_ type shared by packers and unpackers of relocations.
52 // It pastes together a RelocationHolder with some pointers into
53 // code and relocInfo streams.
54
55
56 // Notes on relocType:
57 //
58 // These hold enough information to read or write a value embedded in
59 // the instructions of an CodeBlob. They're used to update:
60 //
61 // 1) embedded oops (isOop() == true)
62 // 2) inline caches (isIC() == true)
63 // 3) runtime calls (isRuntimeCall() == true)
64 // 4) internal word ref (isInternalWord() == true)
65 // 5) external word ref (isExternalWord() == true)
66 //
67 // when objects move (GC) or if code moves (compacting the code heap).
68 // They are also used to patch the code (if a call site must change)
69 //
70 // A relocInfo is represented in 16 bits:
71 // 4 bits indicating the relocation type
72 // 12 bits indicating the offset from the previous relocInfo address
73 //
74 // The offsets accumulate along the relocInfo stream to encode the
75 // address within the CodeBlob, which is named RelocIterator::addr().
76 // The address of a particular relocInfo always points to the first
77 // byte of the relevant instruction (and not to any of its subfields
78 // or embedded immediate constants).
79 //
80 // The offset value is scaled appropriately for the target machine.
81 // (See relocInfo_<arch>.hpp for the offset scaling.)
82 //
83 // On some machines, there may also be a "format" field which may provide
84 // additional information about the format of the instruction stream
85 // at the corresponding code address. The format value is usually zero.
86 // Any machine (such as Intel) whose instructions can sometimes contain
87 // more than one relocatable constant needs format codes to distinguish
88 // which operand goes with a given relocation.
89 //
90 // If the target machine needs N format bits, the offset has 12-N bits,
91 // the format is encoded between the offset and the type, and the
92 // relocInfo_<arch>.hpp file has manifest constants for the format codes.
93 //
94 // If the type is "data_prefix_tag" then the offset bits are further encoded,
95 // and in fact represent not a code-stream offset but some inline data.
96 // The data takes the form of a counted sequence of halfwords, which
97 // precedes the actual relocation record. (Clients never see it directly.)
98 // The interpetation of this extra data depends on the relocation type.
99 //
100 // On machines that have 32-bit immediate fields, there is usually
101 // little need for relocation "prefix" data, because the instruction stream
102 // is a perfectly reasonable place to store the value. On machines in
103 // which 32-bit values must be "split" across instructions, the relocation
104 // data is the "true" specification of the value, which is then applied
105 // to some field of the instruction (22 or 13 bits, on SPARC).
106 //
107 // Whenever the location of the CodeBlob changes, any PC-relative
108 // relocations, and any internal_word_type relocations, must be reapplied.
109 // After the GC runs, oop_type relocations must be reapplied.
110 //
111 //
112 // Here are meanings of the types:
113 //
114 // relocInfo::none -- a filler record
115 // Value: none
116 // Instruction: The corresponding code address is ignored
117 // Data: Any data prefix and format code are ignored
118 // (This means that any relocInfo can be disabled by setting
119 // its type to none. See relocInfo::remove.)
120 //
121 // relocInfo::oop_type -- a reference to an oop
122 // Value: an oop, or else the address (handle) of an oop
123 // Instruction types: memory (load), set (load address)
124 // Data: [] an oop stored in 4 bytes of instruction
125 // [n] n is the index of an oop in the CodeBlob's oop pool
126 // [[N]n l] and l is a byte offset to be applied to the oop
127 // [Nn Ll] both index and offset may be 32 bits if necessary
128 // Here is a special hack, used only by the old compiler:
129 // [[N]n 00] the value is the __address__ of the nth oop in the pool
130 // (Note that the offset allows optimal references to class variables.)
131 //
132 // relocInfo::internal_word_type -- an address within the same CodeBlob
133 // relocInfo::section_word_type -- same, but can refer to another section
134 // Value: an address in the CodeBlob's code or constants section
135 // Instruction types: memory (load), set (load address)
136 // Data: [] stored in 4 bytes of instruction
137 // [[L]l] a relative offset (see [About Offsets] below)
138 // In the case of section_word_type, the offset is relative to a section
139 // base address, and the section number (e.g., SECT_INSTS) is encoded
140 // into the low two bits of the offset L.
141 //
142 // relocInfo::external_word_type -- a fixed address in the runtime system
143 // Value: an address
144 // Instruction types: memory (load), set (load address)
145 // Data: [] stored in 4 bytes of instruction
146 // [n] the index of a "well-known" stub (usual case on RISC)
147 // [Ll] a 32-bit address
148 //
149 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system
150 // Value: an address
151 // Instruction types: PC-relative call (or a PC-relative branch)
152 // Data: [] stored in 4 bytes of instruction
153 //
154 // relocInfo::static_call_type -- a static call
155 // Value: an CodeBlob, a stub, or a fixup routine
156 // Instruction types: a call
157 // Data: []
158 // The identity of the callee is extracted from debugging information.
159 // //%note reloc_3
160 //
161 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline
162 // cache)
163 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine
164 // Instruction types: a call, plus some associated set-oop instructions
165 // Data: [] the associated set-oops are adjacent to the call
166 // [n] n is a relative offset to the first set-oop
167 // [[N]n l] and l is a limit within which the set-oops occur
168 // [Nn Ll] both n and l may be 32 bits if necessary
169 // The identity of the callee is extracted from debugging information.
170 //
171 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound
172 //
173 // Same info as a static_call_type. We use a special type, so the handling of
174 // virtuals and statics are separated.
175 //
176 //
177 // The offset n points to the first set-oop. (See [About Offsets] below.)
178 // In turn, the set-oop instruction specifies or contains an oop cell devoted
179 // exclusively to the IC call, which can be patched along with the call.
180 //
181 // The locations of any other set-oops are found by searching the relocation
182 // information starting at the first set-oop, and continuing until all
183 // relocations up through l have been inspected. The value l is another
184 // relative offset. (Both n and l are relative to the call's first byte.)
185 //
186 // The limit l of the search is exclusive. However, if it points within
187 // the call (e.g., offset zero), it is adjusted to point after the call and
188 // any associated machine-specific delay slot.
189 //
190 // Since the offsets could be as wide as 32-bits, these conventions
191 // put no restrictions whatever upon code reorganization.
192 //
193 // The compiler is responsible for ensuring that transition from a clean
194 // state to a monomorphic compiled state is MP-safe. This implies that
195 // the system must respond well to intermediate states where a random
196 // subset of the set-oops has been correctly from the clean state
197 // upon entry to the VEP of the compiled method. In the case of a
198 // machine (Intel) with a single set-oop instruction, the 32-bit
199 // immediate field must not straddle a unit of memory coherence.
200 // //%note reloc_3
201 //
202 // relocInfo::breakpoint_type -- a conditional breakpoint in the code
203 // Value: none
204 // Instruction types: any whatsoever
205 // Data: [b [T]t i...]
206 // The b is a bit-packed word representing the breakpoint's attributes.
207 // The t is a target address which the breakpoint calls (when it is enabled).
208 // The i... is a place to store one or two instruction words overwritten
209 // by a trap, so that the breakpoint may be subsequently removed.
210 //
211 // relocInfo::static_stub_type -- an extra stub for each static_call_type
212 // Value: none
213 // Instruction types: a virtual call: { set_oop; jump; }
214 // Data: [[N]n] the offset of the associated static_call reloc
215 // This stub becomes the target of a static call which must be upgraded
216 // to a virtual call (because the callee is interpreted).
217 // See [About Offsets] below.
218 // //%note reloc_2
219 //
220 // For example:
221 //
222 // INSTRUCTIONS RELOC: TYPE PREFIX DATA
223 // ------------ ---- -----------
224 // sethi %hi(myObject), R oop_type [n(myObject)]
225 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset]
226 // add R2, 1, R2
227 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset]
228 //%note reloc_1
229 //
230 // This uses 4 instruction words, 8 relocation halfwords,
231 // and an entry (which is sharable) in the CodeBlob's oop pool,
232 // for a total of 36 bytes.
233 //
234 // Note that the compiler is responsible for ensuring the "fldOffset" when
235 // added to "%lo(myObject)" does not overflow the immediate fields of the
236 // memory instructions.
237 //
238 //
239 // [About Offsets] Relative offsets are supplied to this module as
240 // positive byte offsets, but they may be internally stored scaled
241 // and/or negated, depending on what is most compact for the target
242 // system. Since the object pointed to by the offset typically
243 // precedes the relocation address, it is profitable to store
244 // these negative offsets as positive numbers, but this decision
245 // is internal to the relocation information abstractions.
246 //
247
248 class Relocation;
249 class CodeBuffer;
250 class CodeSection;
251 class RelocIterator;
252
253 class relocInfo VALUE_OBJ_CLASS_SPEC {
254 friend class RelocIterator;
255 public:
256 enum relocType {
257 none = 0, // Used when no relocation should be generated
258 oop_type = 1, // embedded oop
259 virtual_call_type = 2, // a standard inline cache call for a virtual send
260 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache)
261 static_call_type = 4, // a static send
262 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case)
263 runtime_call_type = 6, // call to fixed external routine
264 external_word_type = 7, // reference to fixed external address
265 internal_word_type = 8, // reference within the current code blob
266 section_word_type = 9, // internal, but a cross-section reference
267 poll_type = 10, // polling instruction for safepoints
268 poll_return_type = 11, // polling instruction for safepoints at return
269 breakpoint_type = 12, // an initialization barrier or safepoint
270 yet_unused_type = 13, // Still unused
271 yet_unused_type_2 = 14, // Still unused
272 data_prefix_tag = 15, // tag for a prefix (carries data arguments)
273 type_mask = 15 // A mask which selects only the above values
274 };
275
276 protected:
277 unsigned short _value;
278
279 enum RawBitsToken { RAW_BITS };
280 relocInfo(relocType type, RawBitsToken ignore, int bits)
281 : _value((type << nontype_width) + bits) { }
282
283 relocInfo(relocType type, RawBitsToken ignore, int off, int f)
284 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { }
285
286 public:
287 // constructor
288 relocInfo(relocType type, int offset, int format = 0)
289 #ifndef ASSERT
290 {
291 (*this) = relocInfo(type, RAW_BITS, offset, format);
292 }
293 #else
294 // Put a bunch of assertions out-of-line.
295 ;
296 #endif
297
298 #define APPLY_TO_RELOCATIONS(visitor) \
299 visitor(oop) \
300 visitor(virtual_call) \
301 visitor(opt_virtual_call) \
302 visitor(static_call) \
303 visitor(static_stub) \
304 visitor(runtime_call) \
305 visitor(external_word) \
306 visitor(internal_word) \
307 visitor(poll) \
308 visitor(poll_return) \
309 visitor(breakpoint) \
310 visitor(section_word) \
311
312
313 public:
314 enum {
315 value_width = sizeof(unsigned short) * BitsPerByte,
316 type_width = 4, // == log2(type_mask+1)
317 nontype_width = value_width - type_width,
318 datalen_width = nontype_width-1,
319 datalen_tag = 1 << datalen_width, // or-ed into _value
320 datalen_limit = 1 << datalen_width,
321 datalen_mask = (1 << datalen_width)-1
322 };
323
324 // accessors
325 public:
326 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); }
327 int format() const { return format_mask==0? 0: format_mask &
328 ((unsigned)_value >> offset_width); }
329 int addr_offset() const { assert(!is_prefix(), "must have offset");
330 return (_value & offset_mask)*offset_unit; }
331
332 protected:
333 const short* data() const { assert(is_datalen(), "must have data");
334 return (const short*)(this + 1); }
335 int datalen() const { assert(is_datalen(), "must have data");
336 return (_value & datalen_mask); }
337 int immediate() const { assert(is_immediate(), "must have immed");
338 return (_value & datalen_mask); }
339 public:
340 static int addr_unit() { return offset_unit; }
341 static int offset_limit() { return (1 << offset_width) * offset_unit; }
342
343 void set_type(relocType type);
344 void set_format(int format);
345
346 void remove() { set_type(none); }
347
348 protected:
349 bool is_none() const { return type() == none; }
350 bool is_prefix() const { return type() == data_prefix_tag; }
351 bool is_datalen() const { assert(is_prefix(), "must be prefix");
352 return (_value & datalen_tag) != 0; }
353 bool is_immediate() const { assert(is_prefix(), "must be prefix");
354 return (_value & datalen_tag) == 0; }
355
356 public:
357 // Occasionally records of type relocInfo::none will appear in the stream.
358 // We do not bother to filter these out, but clients should ignore them.
359 // These records serve as "filler" in three ways:
360 // - to skip large spans of unrelocated code (this is rare)
361 // - to pad out the relocInfo array to the required oop alignment
362 // - to disable old relocation information which is no longer applicable
363
364 inline friend relocInfo filler_relocInfo();
365
366 // Every non-prefix relocation may be preceded by at most one prefix,
367 // which supplies 1 or more halfwords of associated data. Conventionally,
368 // an int is represented by 0, 1, or 2 halfwords, depending on how
369 // many bits are required to represent the value. (In addition,
370 // if the sole halfword is a 10-bit unsigned number, it is made
371 // "immediate" in the prefix header word itself. This optimization
372 // is invisible outside this module.)
373
374 inline friend relocInfo prefix_relocInfo(int datalen = 0);
375
376 protected:
377 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value
378 static relocInfo immediate_relocInfo(int data0) {
379 assert(fits_into_immediate(data0), "data0 in limits");
380 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0);
381 }
382 static bool fits_into_immediate(int data0) {
383 return (data0 >= 0 && data0 < datalen_limit);
384 }
385
386 public:
387 // Support routines for compilers.
388
389 // This routine takes an infant relocInfo (unprefixed) and
390 // edits in its prefix, if any. It also updates dest.locs_end.
391 void initialize(CodeSection* dest, Relocation* reloc);
392
393 // This routine updates a prefix and returns the limit pointer.
394 // It tries to compress the prefix from 32 to 16 bits, and if
395 // successful returns a reduced "prefix_limit" pointer.
396 relocInfo* finish_prefix(short* prefix_limit);
397
398 // bit-packers for the data array:
399
400 // As it happens, the bytes within the shorts are ordered natively,
401 // but the shorts within the word are ordered big-endian.
402 // This is an arbitrary choice, made this way mainly to ease debugging.
403 static int data0_from_int(jint x) { return x >> value_width; }
404 static int data1_from_int(jint x) { return (short)x; }
405 static jint jint_from_data(short* data) {
406 return (data[0] << value_width) + (unsigned short)data[1];
407 }
408
409 static jint short_data_at(int n, short* data, int datalen) {
410 return datalen > n ? data[n] : 0;
411 }
412
413 static jint jint_data_at(int n, short* data, int datalen) {
414 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen);
415 }
416
417 // Update methods for relocation information
418 // (since code is dynamically patched, we also need to dynamically update the relocation info)
419 // Both methods takes old_type, so it is able to performe sanity checks on the information removed.
420 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type);
421 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type);
422
423 // Machine dependent stuff
424 #ifdef TARGET_ARCH_x86
425 # include "relocInfo_x86.hpp"
426 #endif
427 #ifdef TARGET_ARCH_sparc
428 # include "relocInfo_sparc.hpp"
429 #endif
430 #ifdef TARGET_ARCH_zero
431 # include "relocInfo_zero.hpp"
432 #endif
433 #ifdef TARGET_ARCH_arm
434 # include "relocInfo_arm.hpp"
435 #endif
436 #ifdef TARGET_ARCH_ppc
437 # include "relocInfo_ppc.hpp"
438 #endif
439
440
441 protected:
442 // Derived constant, based on format_width which is PD:
443 enum {
444 offset_width = nontype_width - format_width,
445 offset_mask = (1<<offset_width) - 1,
446 format_mask = (1<<format_width) - 1
447 };
448 public:
449 enum {
450 // Conservatively large estimate of maximum length (in shorts)
451 // of any relocation record (probably breakpoints are largest).
452 // Extended format is length prefix, data words, and tag/offset suffix.
453 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1,
454 have_format = format_width > 0
455 };
456 };
457
458 #define FORWARD_DECLARE_EACH_CLASS(name) \
459 class name##_Relocation;
460 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS)
461 #undef FORWARD_DECLARE_EACH_CLASS
462
463
464
465 inline relocInfo filler_relocInfo() {
466 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit);
467 }
468
469 inline relocInfo prefix_relocInfo(int datalen) {
470 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits");
471 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen);
472 }
473
474
475 // Holder for flyweight relocation objects.
476 // Although the flyweight subclasses are of varying sizes,
477 // the holder is "one size fits all".
478 class RelocationHolder VALUE_OBJ_CLASS_SPEC {
479 friend class Relocation;
480 friend class CodeSection;
481
482 private:
483 // this preallocated memory must accommodate all subclasses of Relocation
484 // (this number is assertion-checked in Relocation::operator new)
485 enum { _relocbuf_size = 5 };
486 void* _relocbuf[ _relocbuf_size ];
487
488 public:
489 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; }
490 inline relocInfo::relocType type() const;
491
492 // Add a constant offset to a relocation. Helper for class Address.
493 RelocationHolder plus(int offset) const;
494
495 inline RelocationHolder(); // initializes type to none
496
497 inline RelocationHolder(Relocation* r); // make a copy
498
499 static const RelocationHolder none;
500 };
501
502 // A RelocIterator iterates through the relocation information of a CodeBlob.
503 // It is a variable BoundRelocation which is able to take on successive
504 // values as it is advanced through a code stream.
505 // Usage:
506 // RelocIterator iter(nm);
507 // while (iter.next()) {
508 // iter.reloc()->some_operation();
509 // }
510 // or:
511 // RelocIterator iter(nm);
512 // while (iter.next()) {
513 // switch (iter.type()) {
514 // case relocInfo::oop_type :
515 // case relocInfo::ic_type :
516 // case relocInfo::prim_type :
517 // case relocInfo::uncommon_type :
518 // case relocInfo::runtime_call_type :
519 // case relocInfo::internal_word_type:
520 // case relocInfo::external_word_type:
521 // ...
522 // }
523 // }
524
525 class RelocIterator : public StackObj {
526 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor
527 friend class Relocation;
528 friend class relocInfo; // for change_reloc_info_for_address only
529 typedef relocInfo::relocType relocType;
530
531 private:
532 address _limit; // stop producing relocations after this _addr
533 relocInfo* _current; // the current relocation information
534 relocInfo* _end; // end marker; we're done iterating when _current == _end
535 nmethod* _code; // compiled method containing _addr
536 address _addr; // instruction to which the relocation applies
537 short _databuf; // spare buffer for compressed data
538 short* _data; // pointer to the relocation's data
539 short _datalen; // number of halfwords in _data
540 char _format; // position within the instruction
541
542 // Base addresses needed to compute targets of section_word_type relocs.
543 address _section_start[SECT_LIMIT];
544 address _section_end [SECT_LIMIT];
545
546 void set_has_current(bool b) {
547 _datalen = !b ? -1 : 0;
548 debug_only(_data = NULL);
549 }
550 void set_current(relocInfo& ri) {
551 _current = &ri;
552 set_has_current(true);
553 }
554
555 RelocationHolder _rh; // where the current relocation is allocated
556
557 relocInfo* current() const { assert(has_current(), "must have current");
558 return _current; }
559
560 void set_limits(address begin, address limit);
561
562 void advance_over_prefix(); // helper method
563
564 void initialize_misc();
565
566 void initialize(nmethod* nm, address begin, address limit);
567
568 friend class PatchingRelocIterator;
569 // make an uninitialized one, for PatchingRelocIterator:
570 RelocIterator() { initialize_misc(); }
571
572 public:
573 // constructor
574 RelocIterator(nmethod* nm, address begin = NULL, address limit = NULL);
575 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL);
576
577 // get next reloc info, return !eos
578 bool next() {
579 _current++;
580 assert(_current <= _end, "must not overrun relocInfo");
581 if (_current == _end) {
582 set_has_current(false);
583 return false;
584 }
585 set_has_current(true);
586
587 if (_current->is_prefix()) {
588 advance_over_prefix();
589 assert(!current()->is_prefix(), "only one prefix at a time");
590 }
591
592 _addr += _current->addr_offset();
593
594 if (_limit != NULL && _addr >= _limit) {
595 set_has_current(false);
596 return false;
597 }
598
599 if (relocInfo::have_format) _format = current()->format();
600 return true;
601 }
602
603 // accessors
604 address limit() const { return _limit; }
605 void set_limit(address x);
606 relocType type() const { return current()->type(); }
607 int format() const { return (relocInfo::have_format) ? current()->format() : 0; }
608 address addr() const { return _addr; }
609 nmethod* code() const { return _code; }
610 short* data() const { return _data; }
611 int datalen() const { return _datalen; }
612 bool has_current() const { return _datalen >= 0; }
613
614 void set_addr(address addr) { _addr = addr; }
615 bool addr_in_const() const;
616
617 address section_start(int n) const {
618 assert(_section_start[n], "must be initialized");
619 return _section_start[n];
620 }
621 address section_end(int n) const {
622 assert(_section_end[n], "must be initialized");
623 return _section_end[n];
624 }
625
626 // The address points to the affected displacement part of the instruction.
627 // For RISC, this is just the whole instruction.
628 // For Intel, this is an unaligned 32-bit word.
629
630 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc.
631 #define EACH_TYPE(name) \
632 inline name##_Relocation* name##_reloc();
633 APPLY_TO_RELOCATIONS(EACH_TYPE)
634 #undef EACH_TYPE
635 // generic relocation accessor; switches on type to call the above
636 Relocation* reloc();
637
638 // CodeBlob's have relocation indexes for faster random access:
639 static int locs_and_index_size(int code_size, int locs_size);
640 // Store an index into [dest_start+dest_count..dest_end).
641 // At dest_start[0..dest_count] is the actual relocation information.
642 // Everything else up to dest_end is free space for the index.
643 static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end);
644
645 #ifndef PRODUCT
646 public:
647 void print();
648 void print_current();
649 #endif
650 };
651
652
653 // A Relocation is a flyweight object allocated within a RelocationHolder.
654 // It represents the relocation data of relocation record.
655 // So, the RelocIterator unpacks relocInfos into Relocations.
656
657 class Relocation VALUE_OBJ_CLASS_SPEC {
658 friend class RelocationHolder;
659 friend class RelocIterator;
660
661 private:
662 static void guarantee_size();
663
664 // When a relocation has been created by a RelocIterator,
665 // this field is non-null. It allows the relocation to know
666 // its context, such as the address to which it applies.
667 RelocIterator* _binding;
668
669 protected:
670 RelocIterator* binding() const {
671 assert(_binding != NULL, "must be bound");
672 return _binding;
673 }
674 void set_binding(RelocIterator* b) {
675 assert(_binding == NULL, "must be unbound");
676 _binding = b;
677 assert(_binding != NULL, "must now be bound");
678 }
679
680 Relocation() {
681 _binding = NULL;
682 }
683
684 static RelocationHolder newHolder() {
685 return RelocationHolder();
686 }
687
688 public:
689 void* operator new(size_t size, const RelocationHolder& holder) {
690 if (size > sizeof(holder._relocbuf)) guarantee_size();
691 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree");
692 return holder.reloc();
693 }
694
695 // make a generic relocation for a given type (if possible)
696 static RelocationHolder spec_simple(relocInfo::relocType rtype);
697
698 // here is the type-specific hook which writes relocation data:
699 virtual void pack_data_to(CodeSection* dest) { }
700
701 // here is the type-specific hook which reads (unpacks) relocation data:
702 virtual void unpack_data() {
703 assert(datalen()==0 || type()==relocInfo::none, "no data here");
704 }
705
706 static bool is_reloc_index(intptr_t index) {
707 return 0 < index && index < os::vm_page_size();
708 }
709
710 protected:
711 // Helper functions for pack_data_to() and unpack_data().
712
713 // Most of the compression logic is confined here.
714 // (The "immediate data" mechanism of relocInfo works independently
715 // of this stuff, and acts to further compress most 1-word data prefixes.)
716
717 // A variable-width int is encoded as a short if it will fit in 16 bits.
718 // The decoder looks at datalen to decide whether to unpack short or jint.
719 // Most relocation records are quite simple, containing at most two ints.
720
721 static bool is_short(jint x) { return x == (short)x; }
722 static short* add_short(short* p, int x) { *p++ = x; return p; }
723 static short* add_jint (short* p, jint x) {
724 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x);
725 return p;
726 }
727 static short* add_var_int(short* p, jint x) { // add a variable-width int
728 if (is_short(x)) p = add_short(p, x);
729 else p = add_jint (p, x);
730 return p;
731 }
732
733 static short* pack_1_int_to(short* p, jint x0) {
734 // Format is one of: [] [x] [Xx]
735 if (x0 != 0) p = add_var_int(p, x0);
736 return p;
737 }
738 int unpack_1_int() {
739 assert(datalen() <= 2, "too much data");
740 return relocInfo::jint_data_at(0, data(), datalen());
741 }
742
743 // With two ints, the short form is used only if both ints are short.
744 short* pack_2_ints_to(short* p, jint x0, jint x1) {
745 // Format is one of: [] [x y?] [Xx Y?y]
746 if (x0 == 0 && x1 == 0) {
747 // no halfwords needed to store zeroes
748 } else if (is_short(x0) && is_short(x1)) {
749 // 1-2 halfwords needed to store shorts
750 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1);
751 } else {
752 // 3-4 halfwords needed to store jints
753 p = add_jint(p, x0); p = add_var_int(p, x1);
754 }
755 return p;
756 }
757 void unpack_2_ints(jint& x0, jint& x1) {
758 int dlen = datalen();
759 short* dp = data();
760 if (dlen <= 2) {
761 x0 = relocInfo::short_data_at(0, dp, dlen);
762 x1 = relocInfo::short_data_at(1, dp, dlen);
763 } else {
764 assert(dlen <= 4, "too much data");
765 x0 = relocInfo::jint_data_at(0, dp, dlen);
766 x1 = relocInfo::jint_data_at(2, dp, dlen);
767 }
768 }
769
770 protected:
771 // platform-dependent utilities for decoding and patching instructions
772 void pd_set_data_value (address x, intptr_t off, bool verify_only = false); // a set or mem-ref
773 void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); }
774 address pd_call_destination (address orig_addr = NULL);
775 void pd_set_call_destination (address x);
776 void pd_swap_in_breakpoint (address x, short* instrs, int instrlen);
777 void pd_swap_out_breakpoint (address x, short* instrs, int instrlen);
778 static int pd_breakpoint_size ();
779
780 // this extracts the address of an address in the code stream instead of the reloc data
781 address* pd_address_in_code ();
782
783 // this extracts an address from the code stream instead of the reloc data
784 address pd_get_address_from_code ();
785
786 // these convert from byte offsets, to scaled offsets, to addresses
787 static jint scaled_offset(address x, address base) {
788 int byte_offset = x - base;
789 int offset = -byte_offset / relocInfo::addr_unit();
790 assert(address_from_scaled_offset(offset, base) == x, "just checkin'");
791 return offset;
792 }
793 static jint scaled_offset_null_special(address x, address base) {
794 // Some relocations treat offset=0 as meaning NULL.
795 // Handle this extra convention carefully.
796 if (x == NULL) return 0;
797 assert(x != base, "offset must not be zero");
798 return scaled_offset(x, base);
799 }
800 static address address_from_scaled_offset(jint offset, address base) {
801 int byte_offset = -( offset * relocInfo::addr_unit() );
802 return base + byte_offset;
803 }
804
805 // these convert between indexes and addresses in the runtime system
806 static int32_t runtime_address_to_index(address runtime_address);
807 static address index_to_runtime_address(int32_t index);
808
809 // helpers for mapping between old and new addresses after a move or resize
810 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest);
811 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest);
812 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false);
813
814 public:
815 // accessors which only make sense for a bound Relocation
816 address addr() const { return binding()->addr(); }
817 nmethod* code() const { return binding()->code(); }
818 bool addr_in_const() const { return binding()->addr_in_const(); }
819 protected:
820 short* data() const { return binding()->data(); }
821 int datalen() const { return binding()->datalen(); }
822 int format() const { return binding()->format(); }
823
824 public:
825 virtual relocInfo::relocType type() { return relocInfo::none; }
826
827 // is it a call instruction?
828 virtual bool is_call() { return false; }
829
830 // is it a data movement instruction?
831 virtual bool is_data() { return false; }
832
833 // some relocations can compute their own values
834 virtual address value();
835
836 // all relocations are able to reassert their values
837 virtual void set_value(address x);
838
839 virtual void clear_inline_cache() { }
840
841 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and
842 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is
843 // probably a reasonable assumption, since empty caches simplifies code reloacation.
844 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { }
845
846 void print();
847 };
848
849
850 // certain inlines must be deferred until class Relocation is defined:
851
852 inline RelocationHolder::RelocationHolder() {
853 // initialize the vtbl, just to keep things type-safe
854 new(*this) Relocation();
855 }
856
857
858 inline RelocationHolder::RelocationHolder(Relocation* r) {
859 // wordwise copy from r (ok if it copies garbage after r)
860 for (int i = 0; i < _relocbuf_size; i++) {
861 _relocbuf[i] = ((void**)r)[i];
862 }
863 }
864
865
866 relocInfo::relocType RelocationHolder::type() const {
867 return reloc()->type();
868 }
869
870 // A DataRelocation always points at a memory or load-constant instruction..
871 // It is absolute on most machines, and the constant is split on RISCs.
872 // The specific subtypes are oop, external_word, and internal_word.
873 // By convention, the "value" does not include a separately reckoned "offset".
874 class DataRelocation : public Relocation {
875 public:
876 bool is_data() { return true; }
877
878 // both target and offset must be computed somehow from relocation data
879 virtual int offset() { return 0; }
880 address value() = 0;
881 void set_value(address x) { set_value(x, offset()); }
882 void set_value(address x, intptr_t o) {
883 if (addr_in_const())
884 *(address*)addr() = x;
885 else
886 pd_set_data_value(x, o);
887 }
888 void verify_value(address x) {
889 if (addr_in_const())
890 assert(*(address*)addr() == x, "must agree");
891 else
892 pd_verify_data_value(x, offset());
893 }
894
895 // The "o" (displacement) argument is relevant only to split relocations
896 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns
897 // can encode more than 32 bits between them. This allows compilers to
898 // share set-hi instructions between addresses that differ by a small
899 // offset (e.g., different static variables in the same class).
900 // On such machines, the "x" argument to set_value on all set-lo
901 // instructions must be the same as the "x" argument for the
902 // corresponding set-hi instructions. The "o" arguments for the
903 // set-hi instructions are ignored, and must not affect the high-half
904 // immediate constant. The "o" arguments for the set-lo instructions are
905 // added into the low-half immediate constant, and must not overflow it.
906 };
907
908 // A CallRelocation always points at a call instruction.
909 // It is PC-relative on most machines.
910 class CallRelocation : public Relocation {
911 public:
912 bool is_call() { return true; }
913
914 address destination() { return pd_call_destination(); }
915 void set_destination(address x); // pd_set_call_destination
916
917 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
918 address value() { return destination(); }
919 void set_value(address x) { set_destination(x); }
920 };
921
922 class oop_Relocation : public DataRelocation {
923 relocInfo::relocType type() { return relocInfo::oop_type; }
924
925 public:
926 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll]
927 // an oop in the CodeBlob's oop pool
928 static RelocationHolder spec(int oop_index, int offset = 0) {
929 assert(oop_index > 0, "must be a pool-resident oop");
930 RelocationHolder rh = newHolder();
931 new(rh) oop_Relocation(oop_index, offset);
932 return rh;
933 }
934 // an oop in the instruction stream
935 static RelocationHolder spec_for_immediate() {
936 const int oop_index = 0;
937 const int offset = 0; // if you want an offset, use the oop pool
938 RelocationHolder rh = newHolder();
939 new(rh) oop_Relocation(oop_index, offset);
940 return rh;
941 }
942
943 private:
944 jint _oop_index; // if > 0, index into CodeBlob::oop_at
945 jint _offset; // byte offset to apply to the oop itself
946
947 oop_Relocation(int oop_index, int offset) {
948 _oop_index = oop_index; _offset = offset;
949 }
950
951 friend class RelocIterator;
952 oop_Relocation() { }
953
954 public:
955 int oop_index() { return _oop_index; }
956 int offset() { return _offset; }
957
958 // data is packed in "2_ints" format: [i o] or [Ii Oo]
959 void pack_data_to(CodeSection* dest);
960 void unpack_data();
961
962 void fix_oop_relocation(); // reasserts oop value
963
964 void verify_oop_relocation();
965
966 address value() { return (address) *oop_addr(); }
967
968 bool oop_is_immediate() { return oop_index() == 0; }
969
970 oop* oop_addr(); // addr or &pool[jint_data]
971 oop oop_value(); // *oop_addr
972 // Note: oop_value transparently converts Universe::non_oop_word to NULL.
973 };
974
975 class virtual_call_Relocation : public CallRelocation {
976 relocInfo::relocType type() { return relocInfo::virtual_call_type; }
977
978 public:
979 // "first_oop" points to the first associated set-oop.
980 // The oop_limit helps find the last associated set-oop.
981 // (See comments at the top of this file.)
982 static RelocationHolder spec(address first_oop, address oop_limit = NULL) {
983 RelocationHolder rh = newHolder();
984 new(rh) virtual_call_Relocation(first_oop, oop_limit);
985 return rh;
986 }
987
988 virtual_call_Relocation(address first_oop, address oop_limit) {
989 _first_oop = first_oop; _oop_limit = oop_limit;
990 assert(first_oop != NULL, "first oop address must be specified");
991 }
992
993 private:
994 address _first_oop; // location of first set-oop instruction
995 address _oop_limit; // search limit for set-oop instructions
996
997 friend class RelocIterator;
998 virtual_call_Relocation() { }
999
1000
1001 public:
1002 address first_oop();
1003 address oop_limit();
1004
1005 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll]
1006 // oop_limit is set to 0 if the limit falls somewhere within the call.
1007 // When unpacking, a zero oop_limit is taken to refer to the end of the call.
1008 // (This has the effect of bringing in the call's delay slot on SPARC.)
1009 void pack_data_to(CodeSection* dest);
1010 void unpack_data();
1011
1012 void clear_inline_cache();
1013
1014 // find the matching static_stub
1015 address static_stub();
1016
1017 // Figure out where an ic_call is hiding, given a set-oop or call.
1018 // Either ic_call or first_oop must be non-null; the other is deduced.
1019 // Code if non-NULL must be the nmethod, else it is deduced.
1020 // The address of the patchable oop is also deduced.
1021 // The returned iterator will enumerate over the oops and the ic_call,
1022 // as well as any other relocations that happen to be in that span of code.
1023 // Recognize relevant set_oops with: oop_reloc()->oop_addr() == oop_addr.
1024 static RelocIterator parse_ic(nmethod* &nm, address &ic_call, address &first_oop, oop* &oop_addr, bool *is_optimized);
1025 };
1026
1027
1028 class opt_virtual_call_Relocation : public CallRelocation {
1029 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; }
1030
1031 public:
1032 static RelocationHolder spec() {
1033 RelocationHolder rh = newHolder();
1034 new(rh) opt_virtual_call_Relocation();
1035 return rh;
1036 }
1037
1038 private:
1039 friend class RelocIterator;
1040 opt_virtual_call_Relocation() { }
1041
1042 public:
1043 void clear_inline_cache();
1044
1045 // find the matching static_stub
1046 address static_stub();
1047 };
1048
1049
1050 class static_call_Relocation : public CallRelocation {
1051 relocInfo::relocType type() { return relocInfo::static_call_type; }
1052
1053 public:
1054 static RelocationHolder spec() {
1055 RelocationHolder rh = newHolder();
1056 new(rh) static_call_Relocation();
1057 return rh;
1058 }
1059
1060 private:
1061 friend class RelocIterator;
1062 static_call_Relocation() { }
1063
1064 public:
1065 void clear_inline_cache();
1066
1067 // find the matching static_stub
1068 address static_stub();
1069 };
1070
1071 class static_stub_Relocation : public Relocation {
1072 relocInfo::relocType type() { return relocInfo::static_stub_type; }
1073
1074 public:
1075 static RelocationHolder spec(address static_call) {
1076 RelocationHolder rh = newHolder();
1077 new(rh) static_stub_Relocation(static_call);
1078 return rh;
1079 }
1080
1081 private:
1082 address _static_call; // location of corresponding static_call
1083
1084 static_stub_Relocation(address static_call) {
1085 _static_call = static_call;
1086 }
1087
1088 friend class RelocIterator;
1089 static_stub_Relocation() { }
1090
1091 public:
1092 void clear_inline_cache();
1093
1094 address static_call() { return _static_call; }
1095
1096 // data is packed as a scaled offset in "1_int" format: [c] or [Cc]
1097 void pack_data_to(CodeSection* dest);
1098 void unpack_data();
1099 };
1100
1101 class runtime_call_Relocation : public CallRelocation {
1102 relocInfo::relocType type() { return relocInfo::runtime_call_type; }
1103
1104 public:
1105 static RelocationHolder spec() {
1106 RelocationHolder rh = newHolder();
1107 new(rh) runtime_call_Relocation();
1108 return rh;
1109 }
1110
1111 private:
1112 friend class RelocIterator;
1113 runtime_call_Relocation() { }
1114
1115 public:
1116 };
1117
1118 class external_word_Relocation : public DataRelocation {
1119 relocInfo::relocType type() { return relocInfo::external_word_type; }
1120
1121 public:
1122 static RelocationHolder spec(address target) {
1123 assert(target != NULL, "must not be null");
1124 RelocationHolder rh = newHolder();
1125 new(rh) external_word_Relocation(target);
1126 return rh;
1127 }
1128
1129 // Use this one where all 32/64 bits of the target live in the code stream.
1130 // The target must be an intptr_t, and must be absolute (not relative).
1131 static RelocationHolder spec_for_immediate() {
1132 RelocationHolder rh = newHolder();
1133 new(rh) external_word_Relocation(NULL);
1134 return rh;
1135 }
1136
1137 // Some address looking values aren't safe to treat as relocations
1138 // and should just be treated as constants.
1139 static bool can_be_relocated(address target) {
1140 return target != NULL && !is_reloc_index((intptr_t)target);
1141 }
1142
1143 private:
1144 address _target; // address in runtime
1145
1146 external_word_Relocation(address target) {
1147 _target = target;
1148 }
1149
1150 friend class RelocIterator;
1151 external_word_Relocation() { }
1152
1153 public:
1154 // data is packed as a well-known address in "1_int" format: [a] or [Aa]
1155 // The function runtime_address_to_index is used to turn full addresses
1156 // to short indexes, if they are pre-registered by the stub mechanism.
1157 // If the "a" value is 0 (i.e., _target is NULL), the address is stored
1158 // in the code stream. See external_word_Relocation::target().
1159 void pack_data_to(CodeSection* dest);
1160 void unpack_data();
1161
1162 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1163 address target(); // if _target==NULL, fetch addr from code stream
1164 address value() { return target(); }
1165 };
1166
1167 class internal_word_Relocation : public DataRelocation {
1168 relocInfo::relocType type() { return relocInfo::internal_word_type; }
1169
1170 public:
1171 static RelocationHolder spec(address target) {
1172 assert(target != NULL, "must not be null");
1173 RelocationHolder rh = newHolder();
1174 new(rh) internal_word_Relocation(target);
1175 return rh;
1176 }
1177
1178 // use this one where all the bits of the target can fit in the code stream:
1179 static RelocationHolder spec_for_immediate() {
1180 RelocationHolder rh = newHolder();
1181 new(rh) internal_word_Relocation(NULL);
1182 return rh;
1183 }
1184
1185 internal_word_Relocation(address target) {
1186 _target = target;
1187 _section = -1; // self-relative
1188 }
1189
1190 protected:
1191 address _target; // address in CodeBlob
1192 int _section; // section providing base address, if any
1193
1194 friend class RelocIterator;
1195 internal_word_Relocation() { }
1196
1197 // bit-width of LSB field in packed offset, if section >= 0
1198 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits
1199
1200 public:
1201 // data is packed as a scaled offset in "1_int" format: [o] or [Oo]
1202 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored
1203 // in the code stream. See internal_word_Relocation::target().
1204 // If _section is not -1, it is appended to the low bits of the offset.
1205 void pack_data_to(CodeSection* dest);
1206 void unpack_data();
1207
1208 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1209 address target(); // if _target==NULL, fetch addr from code stream
1210 int section() { return _section; }
1211 address value() { return target(); }
1212 };
1213
1214 class section_word_Relocation : public internal_word_Relocation {
1215 relocInfo::relocType type() { return relocInfo::section_word_type; }
1216
1217 public:
1218 static RelocationHolder spec(address target, int section) {
1219 RelocationHolder rh = newHolder();
1220 new(rh) section_word_Relocation(target, section);
1221 return rh;
1222 }
1223
1224 section_word_Relocation(address target, int section) {
1225 assert(target != NULL, "must not be null");
1226 assert(section >= 0, "must be a valid section");
1227 _target = target;
1228 _section = section;
1229 }
1230
1231 //void pack_data_to -- inherited
1232 void unpack_data();
1233
1234 private:
1235 friend class RelocIterator;
1236 section_word_Relocation() { }
1237 };
1238
1239
1240 class poll_Relocation : public Relocation {
1241 bool is_data() { return true; }
1242 relocInfo::relocType type() { return relocInfo::poll_type; }
1243 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1244 };
1245
1246 class poll_return_Relocation : public Relocation {
1247 bool is_data() { return true; }
1248 relocInfo::relocType type() { return relocInfo::poll_return_type; }
1249 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1250 };
1251
1252
1253 class breakpoint_Relocation : public Relocation {
1254 relocInfo::relocType type() { return relocInfo::breakpoint_type; }
1255
1256 enum {
1257 // attributes which affect the interpretation of the data:
1258 removable_attr = 0x0010, // buffer [i...] allows for undoing the trap
1259 internal_attr = 0x0020, // the target is an internal addr (local stub)
1260 settable_attr = 0x0040, // the target is settable
1261
1262 // states which can change over time:
1263 enabled_state = 0x0100, // breakpoint must be active in running code
1264 active_state = 0x0200, // breakpoint instruction actually in code
1265
1266 kind_mask = 0x000F, // mask for extracting kind
1267 high_bit = 0x4000 // extra bit which is always set
1268 };
1269
1270 public:
1271 enum {
1272 // kinds:
1273 initialization = 1,
1274 safepoint = 2
1275 };
1276
1277 // If target is NULL, 32 bits are reserved for a later set_target().
1278 static RelocationHolder spec(int kind, address target = NULL, bool internal_target = false) {
1279 RelocationHolder rh = newHolder();
1280 new(rh) breakpoint_Relocation(kind, target, internal_target);
1281 return rh;
1282 }
1283
1284 private:
1285 // We require every bits value to NOT to fit into relocInfo::datalen_width,
1286 // because we are going to actually store state in the reloc, and so
1287 // cannot allow it to be compressed (and hence copied by the iterator).
1288
1289 short _bits; // bit-encoded kind, attrs, & state
1290 address _target;
1291
1292 breakpoint_Relocation(int kind, address target, bool internal_target);
1293
1294 friend class RelocIterator;
1295 breakpoint_Relocation() { }
1296
1297 short bits() const { return _bits; }
1298 short& live_bits() const { return data()[0]; }
1299 short* instrs() const { return data() + datalen() - instrlen(); }
1300 int instrlen() const { return removable() ? pd_breakpoint_size() : 0; }
1301
1302 void set_bits(short x) {
1303 assert(live_bits() == _bits, "must be the only mutator of reloc info");
1304 live_bits() = _bits = x;
1305 }
1306
1307 public:
1308 address target() const;
1309 void set_target(address x);
1310
1311 int kind() const { return bits() & kind_mask; }
1312 bool enabled() const { return (bits() & enabled_state) != 0; }
1313 bool active() const { return (bits() & active_state) != 0; }
1314 bool internal() const { return (bits() & internal_attr) != 0; }
1315 bool removable() const { return (bits() & removable_attr) != 0; }
1316 bool settable() const { return (bits() & settable_attr) != 0; }
1317
1318 void set_enabled(bool b); // to activate, you must also say set_active
1319 void set_active(bool b); // actually inserts bpt (must be enabled 1st)
1320
1321 // data is packed as 16 bits, followed by the target (1 or 2 words), followed
1322 // if necessary by empty storage for saving away original instruction bytes.
1323 void pack_data_to(CodeSection* dest);
1324 void unpack_data();
1325
1326 // during certain operations, breakpoints must be out of the way:
1327 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
1328 assert(!active(), "cannot perform relocation on enabled breakpoints");
1329 }
1330 };
1331
1332
1333 // We know all the xxx_Relocation classes, so now we can define these:
1334 #define EACH_CASE(name) \
1335 inline name##_Relocation* RelocIterator::name##_reloc() { \
1336 assert(type() == relocInfo::name##_type, "type must agree"); \
1337 /* The purpose of the placed "new" is to re-use the same */ \
1338 /* stack storage for each new iteration. */ \
1339 name##_Relocation* r = new(_rh) name##_Relocation(); \
1340 r->set_binding(this); \
1341 r->name##_Relocation::unpack_data(); \
1342 return r; \
1343 }
1344 APPLY_TO_RELOCATIONS(EACH_CASE);
1345 #undef EACH_CASE
1346
1347 inline RelocIterator::RelocIterator(nmethod* nm, address begin, address limit) {
1348 initialize(nm, begin, limit);
1349 }
1350
1351 // if you are going to patch code, you should use this subclass of
1352 // RelocIterator
1353 class PatchingRelocIterator : public RelocIterator {
1354 private:
1355 RelocIterator _init_state;
1356
1357 void prepass(); // deactivates all breakpoints
1358 void postpass(); // reactivates all enabled breakpoints
1359
1360 // do not copy these puppies; it would have unpredictable side effects
1361 // these are private and have no bodies defined because they should not be called
1362 PatchingRelocIterator(const RelocIterator&);
1363 void operator=(const RelocIterator&);
1364
1365 public:
1366 PatchingRelocIterator(nmethod* nm, address begin = NULL, address limit = NULL)
1367 : RelocIterator(nm, begin, limit) { prepass(); }
1368
1369 ~PatchingRelocIterator() { postpass(); }
1370 };
1371
1372 #endif // SHARE_VM_CODE_RELOCINFO_HPP