1 /*
2 * Copyright (c) 1997, 2016, 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
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11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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13 * accompanied this code).
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23 */
24
25 #ifndef SHARE_VM_CODE_RELOCINFO_HPP
26 #define SHARE_VM_CODE_RELOCINFO_HPP
27
28 #include "memory/allocation.hpp"
29 #include "runtime/os.hpp"
30
31 class nmethod;
32 class CompiledMethod;
33 class Metadata;
34 class NativeMovConstReg;
35
36 // Types in this file:
37 // relocInfo
38 // One element of an array of halfwords encoding compressed relocations.
39 // Also, the source of relocation types (relocInfo::oop_type, ...).
40 // Relocation
41 // A flyweight object representing a single relocation.
42 // It is fully unpacked from the compressed relocation array.
43 // metadata_Relocation, ... (subclasses of Relocation)
44 // The location of some type-specific operations (metadata_addr, ...).
45 // Also, the source of relocation specs (metadata_Relocation::spec, ...).
46 // oop_Relocation, ... (subclasses of Relocation)
47 // oops in the code stream (strings, class loaders)
48 // Also, the source of relocation specs (oop_Relocation::spec, ...).
49 // RelocationHolder
50 // A ValueObj type which acts as a union holding a Relocation object.
51 // Represents a relocation spec passed into a CodeBuffer during assembly.
52 // RelocIterator
53 // A StackObj which iterates over the relocations associated with
54 // a range of code addresses. Can be used to operate a copy of code.
55 // BoundRelocation
56 // An _internal_ type shared by packers and unpackers of relocations.
57 // It pastes together a RelocationHolder with some pointers into
58 // code and relocInfo streams.
59
60
61 // Notes on relocType:
62 //
63 // These hold enough information to read or write a value embedded in
64 // the instructions of an CodeBlob. They're used to update:
65 //
66 // 1) embedded oops (isOop() == true)
67 // 2) inline caches (isIC() == true)
68 // 3) runtime calls (isRuntimeCall() == true)
69 // 4) internal word ref (isInternalWord() == true)
70 // 5) external word ref (isExternalWord() == true)
71 //
72 // when objects move (GC) or if code moves (compacting the code heap).
73 // They are also used to patch the code (if a call site must change)
74 //
75 // A relocInfo is represented in 16 bits:
76 // 4 bits indicating the relocation type
77 // 12 bits indicating the offset from the previous relocInfo address
78 //
79 // The offsets accumulate along the relocInfo stream to encode the
80 // address within the CodeBlob, which is named RelocIterator::addr().
81 // The address of a particular relocInfo always points to the first
82 // byte of the relevant instruction (and not to any of its subfields
83 // or embedded immediate constants).
84 //
85 // The offset value is scaled appropriately for the target machine.
86 // (See relocInfo_<arch>.hpp for the offset scaling.)
87 //
88 // On some machines, there may also be a "format" field which may provide
89 // additional information about the format of the instruction stream
90 // at the corresponding code address. The format value is usually zero.
91 // Any machine (such as Intel) whose instructions can sometimes contain
92 // more than one relocatable constant needs format codes to distinguish
93 // which operand goes with a given relocation.
94 //
95 // If the target machine needs N format bits, the offset has 12-N bits,
96 // the format is encoded between the offset and the type, and the
97 // relocInfo_<arch>.hpp file has manifest constants for the format codes.
98 //
99 // If the type is "data_prefix_tag" then the offset bits are further encoded,
100 // and in fact represent not a code-stream offset but some inline data.
101 // The data takes the form of a counted sequence of halfwords, which
102 // precedes the actual relocation record. (Clients never see it directly.)
103 // The interpetation of this extra data depends on the relocation type.
104 //
105 // On machines that have 32-bit immediate fields, there is usually
106 // little need for relocation "prefix" data, because the instruction stream
107 // is a perfectly reasonable place to store the value. On machines in
108 // which 32-bit values must be "split" across instructions, the relocation
109 // data is the "true" specification of the value, which is then applied
110 // to some field of the instruction (22 or 13 bits, on SPARC).
111 //
112 // Whenever the location of the CodeBlob changes, any PC-relative
113 // relocations, and any internal_word_type relocations, must be reapplied.
114 // After the GC runs, oop_type relocations must be reapplied.
115 //
116 //
117 // Here are meanings of the types:
118 //
119 // relocInfo::none -- a filler record
120 // Value: none
121 // Instruction: The corresponding code address is ignored
122 // Data: Any data prefix and format code are ignored
123 // (This means that any relocInfo can be disabled by setting
124 // its type to none. See relocInfo::remove.)
125 //
126 // relocInfo::oop_type, relocInfo::metadata_type -- a reference to an oop or meta data
127 // Value: an oop, or else the address (handle) of an oop
128 // Instruction types: memory (load), set (load address)
129 // Data: [] an oop stored in 4 bytes of instruction
130 // [n] n is the index of an oop in the CodeBlob's oop pool
131 // [[N]n l] and l is a byte offset to be applied to the oop
132 // [Nn Ll] both index and offset may be 32 bits if necessary
133 // Here is a special hack, used only by the old compiler:
134 // [[N]n 00] the value is the __address__ of the nth oop in the pool
135 // (Note that the offset allows optimal references to class variables.)
136 //
137 // relocInfo::internal_word_type -- an address within the same CodeBlob
138 // relocInfo::section_word_type -- same, but can refer to another section
139 // Value: an address in the CodeBlob's code or constants section
140 // Instruction types: memory (load), set (load address)
141 // Data: [] stored in 4 bytes of instruction
142 // [[L]l] a relative offset (see [About Offsets] below)
143 // In the case of section_word_type, the offset is relative to a section
144 // base address, and the section number (e.g., SECT_INSTS) is encoded
145 // into the low two bits of the offset L.
146 //
147 // relocInfo::external_word_type -- a fixed address in the runtime system
148 // Value: an address
149 // Instruction types: memory (load), set (load address)
150 // Data: [] stored in 4 bytes of instruction
151 // [n] the index of a "well-known" stub (usual case on RISC)
152 // [Ll] a 32-bit address
153 //
154 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system
155 // Value: an address
156 // Instruction types: PC-relative call (or a PC-relative branch)
157 // Data: [] stored in 4 bytes of instruction
158 //
159 // relocInfo::static_call_type -- a static call
160 // Value: an CodeBlob, a stub, or a fixup routine
161 // Instruction types: a call
162 // Data: []
163 // The identity of the callee is extracted from debugging information.
164 // //%note reloc_3
165 //
166 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline
167 // cache)
168 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine
169 // Instruction types: a call, plus some associated set-oop instructions
170 // Data: [] the associated set-oops are adjacent to the call
171 // [n] n is a relative offset to the first set-oop
172 // [[N]n l] and l is a limit within which the set-oops occur
173 // [Nn Ll] both n and l may be 32 bits if necessary
174 // The identity of the callee is extracted from debugging information.
175 //
176 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound
177 //
178 // Same info as a static_call_type. We use a special type, so the handling of
179 // virtuals and statics are separated.
180 //
181 //
182 // The offset n points to the first set-oop. (See [About Offsets] below.)
183 // In turn, the set-oop instruction specifies or contains an oop cell devoted
184 // exclusively to the IC call, which can be patched along with the call.
185 //
186 // The locations of any other set-oops are found by searching the relocation
187 // information starting at the first set-oop, and continuing until all
188 // relocations up through l have been inspected. The value l is another
189 // relative offset. (Both n and l are relative to the call's first byte.)
190 //
191 // The limit l of the search is exclusive. However, if it points within
192 // the call (e.g., offset zero), it is adjusted to point after the call and
193 // any associated machine-specific delay slot.
194 //
195 // Since the offsets could be as wide as 32-bits, these conventions
196 // put no restrictions whatever upon code reorganization.
197 //
198 // The compiler is responsible for ensuring that transition from a clean
199 // state to a monomorphic compiled state is MP-safe. This implies that
200 // the system must respond well to intermediate states where a random
201 // subset of the set-oops has been correctly from the clean state
202 // upon entry to the VEP of the compiled method. In the case of a
203 // machine (Intel) with a single set-oop instruction, the 32-bit
204 // immediate field must not straddle a unit of memory coherence.
205 // //%note reloc_3
206 //
207 // relocInfo::static_stub_type -- an extra stub for each static_call_type
208 // Value: none
209 // Instruction types: a virtual call: { set_oop; jump; }
210 // Data: [[N]n] the offset of the associated static_call reloc
211 // This stub becomes the target of a static call which must be upgraded
212 // to a virtual call (because the callee is interpreted).
213 // See [About Offsets] below.
214 // //%note reloc_2
215 //
216 // relocInfo::poll_[return_]type -- a safepoint poll
217 // Value: none
218 // Instruction types: memory load or test
219 // Data: none
220 //
221 // For example:
222 //
223 // INSTRUCTIONS RELOC: TYPE PREFIX DATA
224 // ------------ ---- -----------
225 // sethi %hi(myObject), R oop_type [n(myObject)]
226 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset]
227 // add R2, 1, R2
228 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset]
229 //%note reloc_1
230 //
231 // This uses 4 instruction words, 8 relocation halfwords,
232 // and an entry (which is sharable) in the CodeBlob's oop pool,
233 // for a total of 36 bytes.
234 //
235 // Note that the compiler is responsible for ensuring the "fldOffset" when
236 // added to "%lo(myObject)" does not overflow the immediate fields of the
237 // memory instructions.
238 //
239 //
240 // [About Offsets] Relative offsets are supplied to this module as
241 // positive byte offsets, but they may be internally stored scaled
242 // and/or negated, depending on what is most compact for the target
243 // system. Since the object pointed to by the offset typically
244 // precedes the relocation address, it is profitable to store
245 // these negative offsets as positive numbers, but this decision
246 // is internal to the relocation information abstractions.
247 //
248
249 class Relocation;
250 class CodeBuffer;
251 class CodeSection;
252 class RelocIterator;
253
254 class relocInfo VALUE_OBJ_CLASS_SPEC {
255 friend class RelocIterator;
256 public:
257 enum relocType {
258 none = 0, // Used when no relocation should be generated
259 oop_type = 1, // embedded oop
260 virtual_call_type = 2, // a standard inline cache call for a virtual send
261 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache)
262 static_call_type = 4, // a static send
263 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case)
264 runtime_call_type = 6, // call to fixed external routine
265 external_word_type = 7, // reference to fixed external address
266 internal_word_type = 8, // reference within the current code blob
267 section_word_type = 9, // internal, but a cross-section reference
268 poll_type = 10, // polling instruction for safepoints
269 poll_return_type = 11, // polling instruction for safepoints at return
270 metadata_type = 12, // metadata that used to be oops
271 trampoline_stub_type = 13, // stub-entry for trampoline
272 yet_unused_type_1 = 14, // Still unused
273 data_prefix_tag = 15, // tag for a prefix (carries data arguments)
274 type_mask = 15 // A mask which selects only the above values
275 };
276
277 protected:
278 unsigned short _value;
279
280 enum RawBitsToken { RAW_BITS };
281 relocInfo(relocType type, RawBitsToken ignore, int bits)
282 : _value((type << nontype_width) + bits) { }
283
284 relocInfo(relocType type, RawBitsToken ignore, int off, int f)
285 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { }
286
287 public:
288 // constructor
289 relocInfo(relocType type, int offset, int format = 0)
290 #ifndef ASSERT
291 {
292 (*this) = relocInfo(type, RAW_BITS, offset, format);
293 }
294 #else
295 // Put a bunch of assertions out-of-line.
296 ;
297 #endif
298
299 #define APPLY_TO_RELOCATIONS(visitor) \
300 visitor(oop) \
301 visitor(metadata) \
302 visitor(virtual_call) \
303 visitor(opt_virtual_call) \
304 visitor(static_call) \
305 visitor(static_stub) \
306 visitor(runtime_call) \
307 visitor(external_word) \
308 visitor(internal_word) \
309 visitor(poll) \
310 visitor(poll_return) \
311 visitor(section_word) \
312 visitor(trampoline_stub) \
313
314
315 public:
316 enum {
317 value_width = sizeof(unsigned short) * BitsPerByte,
318 type_width = 4, // == log2(type_mask+1)
319 nontype_width = value_width - type_width,
320 datalen_width = nontype_width-1,
321 datalen_tag = 1 << datalen_width, // or-ed into _value
322 datalen_limit = 1 << datalen_width,
323 datalen_mask = (1 << datalen_width)-1
324 };
325
326 // accessors
327 public:
328 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); }
329 int format() const { return format_mask==0? 0: format_mask &
330 ((unsigned)_value >> offset_width); }
331 int addr_offset() const { assert(!is_prefix(), "must have offset");
332 return (_value & offset_mask)*offset_unit; }
333
334 protected:
335 const short* data() const { assert(is_datalen(), "must have data");
336 return (const short*)(this + 1); }
337 int datalen() const { assert(is_datalen(), "must have data");
338 return (_value & datalen_mask); }
339 int immediate() const { assert(is_immediate(), "must have immed");
340 return (_value & datalen_mask); }
341 public:
342 static int addr_unit() { return offset_unit; }
343 static int offset_limit() { return (1 << offset_width) * offset_unit; }
344
345 void set_type(relocType type);
346 void set_format(int format);
347
348 void remove() { set_type(none); }
349
350 protected:
351 bool is_none() const { return type() == none; }
352 bool is_prefix() const { return type() == data_prefix_tag; }
353 bool is_datalen() const { assert(is_prefix(), "must be prefix");
354 return (_value & datalen_tag) != 0; }
355 bool is_immediate() const { assert(is_prefix(), "must be prefix");
356 return (_value & datalen_tag) == 0; }
357
358 public:
359 // Occasionally records of type relocInfo::none will appear in the stream.
360 // We do not bother to filter these out, but clients should ignore them.
361 // These records serve as "filler" in three ways:
362 // - to skip large spans of unrelocated code (this is rare)
363 // - to pad out the relocInfo array to the required oop alignment
364 // - to disable old relocation information which is no longer applicable
365
366 inline friend relocInfo filler_relocInfo();
367
368 // Every non-prefix relocation may be preceded by at most one prefix,
369 // which supplies 1 or more halfwords of associated data. Conventionally,
370 // an int is represented by 0, 1, or 2 halfwords, depending on how
371 // many bits are required to represent the value. (In addition,
372 // if the sole halfword is a 10-bit unsigned number, it is made
373 // "immediate" in the prefix header word itself. This optimization
374 // is invisible outside this module.)
375
376 inline friend relocInfo prefix_relocInfo(int datalen);
377
378 protected:
379 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value
380 static relocInfo immediate_relocInfo(int data0) {
381 assert(fits_into_immediate(data0), "data0 in limits");
382 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0);
383 }
384 static bool fits_into_immediate(int data0) {
385 return (data0 >= 0 && data0 < datalen_limit);
386 }
387
388 public:
389 // Support routines for compilers.
390
391 // This routine takes an infant relocInfo (unprefixed) and
392 // edits in its prefix, if any. It also updates dest.locs_end.
393 void initialize(CodeSection* dest, Relocation* reloc);
394
395 // This routine updates a prefix and returns the limit pointer.
396 // It tries to compress the prefix from 32 to 16 bits, and if
397 // successful returns a reduced "prefix_limit" pointer.
398 relocInfo* finish_prefix(short* prefix_limit);
399
400 // bit-packers for the data array:
401
402 // As it happens, the bytes within the shorts are ordered natively,
403 // but the shorts within the word are ordered big-endian.
404 // This is an arbitrary choice, made this way mainly to ease debugging.
405 static int data0_from_int(jint x) { return x >> value_width; }
406 static int data1_from_int(jint x) { return (short)x; }
407 static jint jint_from_data(short* data) {
408 return (data[0] << value_width) + (unsigned short)data[1];
409 }
410
411 static jint short_data_at(int n, short* data, int datalen) {
412 return datalen > n ? data[n] : 0;
413 }
414
415 static jint jint_data_at(int n, short* data, int datalen) {
416 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen);
417 }
418
419 // Update methods for relocation information
420 // (since code is dynamically patched, we also need to dynamically update the relocation info)
421 // Both methods takes old_type, so it is able to performe sanity checks on the information removed.
422 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type);
423 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type);
424
425 // Machine dependent stuff
426 #ifdef TARGET_ARCH_x86
427 # include "relocInfo_x86.hpp"
428 #endif
429 #ifdef TARGET_ARCH_sparc
430 # include "relocInfo_sparc.hpp"
431 #endif
432 #ifdef TARGET_ARCH_zero
433 # include "relocInfo_zero.hpp"
434 #endif
435 #ifdef TARGET_ARCH_arm
436 # include "relocInfo_arm.hpp"
437 #endif
438 #ifdef TARGET_ARCH_ppc
439 # include "relocInfo_ppc.hpp"
440 #endif
441 #ifdef TARGET_ARCH_aarch64
442 # include "relocInfo_aarch64.hpp"
443 #endif
444
445 protected:
446 // Derived constant, based on format_width which is PD:
447 enum {
448 offset_width = nontype_width - format_width,
449 offset_mask = (1<<offset_width) - 1,
450 format_mask = (1<<format_width) - 1
451 };
452 public:
453 enum {
454 #ifdef _LP64
455 // for use in format
456 // format_width must be at least 1 on _LP64
457 narrow_oop_in_const = 1,
458 #endif
459 // Conservatively large estimate of maximum length (in shorts)
460 // of any relocation record.
461 // Extended format is length prefix, data words, and tag/offset suffix.
462 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1,
463 have_format = format_width > 0
464 };
465 };
466
467 #define FORWARD_DECLARE_EACH_CLASS(name) \
468 class name##_Relocation;
469 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS)
470 #undef FORWARD_DECLARE_EACH_CLASS
471
472
473
474 inline relocInfo filler_relocInfo() {
475 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit);
476 }
477
478 inline relocInfo prefix_relocInfo(int datalen = 0) {
479 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits");
480 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen);
481 }
482
483
484 // Holder for flyweight relocation objects.
485 // Although the flyweight subclasses are of varying sizes,
486 // the holder is "one size fits all".
487 class RelocationHolder VALUE_OBJ_CLASS_SPEC {
488 friend class Relocation;
489 friend class CodeSection;
490
491 private:
492 // this preallocated memory must accommodate all subclasses of Relocation
493 // (this number is assertion-checked in Relocation::operator new)
494 enum { _relocbuf_size = 5 };
495 void* _relocbuf[ _relocbuf_size ];
496
497 public:
498 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; }
499 inline relocInfo::relocType type() const;
500
501 // Add a constant offset to a relocation. Helper for class Address.
502 RelocationHolder plus(int offset) const;
503
504 inline RelocationHolder(); // initializes type to none
505
506 inline RelocationHolder(Relocation* r); // make a copy
507
508 static const RelocationHolder none;
509 };
510
511 // A RelocIterator iterates through the relocation information of a CodeBlob.
512 // It is a variable BoundRelocation which is able to take on successive
513 // values as it is advanced through a code stream.
514 // Usage:
515 // RelocIterator iter(nm);
516 // while (iter.next()) {
517 // iter.reloc()->some_operation();
518 // }
519 // or:
520 // RelocIterator iter(nm);
521 // while (iter.next()) {
522 // switch (iter.type()) {
523 // case relocInfo::oop_type :
524 // case relocInfo::ic_type :
525 // case relocInfo::prim_type :
526 // case relocInfo::uncommon_type :
527 // case relocInfo::runtime_call_type :
528 // case relocInfo::internal_word_type:
529 // case relocInfo::external_word_type:
530 // ...
531 // }
532 // }
533
534 class RelocIterator : public StackObj {
535 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor
536 friend class Relocation;
537 friend class relocInfo; // for change_reloc_info_for_address only
538 typedef relocInfo::relocType relocType;
539
540 private:
541 address _limit; // stop producing relocations after this _addr
542 relocInfo* _current; // the current relocation information
543 relocInfo* _end; // end marker; we're done iterating when _current == _end
544 CompiledMethod* _code; // compiled method containing _addr
545 address _addr; // instruction to which the relocation applies
546 short _databuf; // spare buffer for compressed data
547 short* _data; // pointer to the relocation's data
548 short _datalen; // number of halfwords in _data
549 char _format; // position within the instruction
550
551 // Base addresses needed to compute targets of section_word_type relocs.
552 address _section_start[SECT_LIMIT];
553 address _section_end [SECT_LIMIT];
554
555 void set_has_current(bool b) {
556 _datalen = !b ? -1 : 0;
557 debug_only(_data = NULL);
558 }
559 void set_current(relocInfo& ri) {
560 _current = &ri;
561 set_has_current(true);
562 }
563
564 RelocationHolder _rh; // where the current relocation is allocated
565
566 relocInfo* current() const { assert(has_current(), "must have current");
567 return _current; }
568
569 void set_limits(address begin, address limit);
570
571 void advance_over_prefix(); // helper method
572
573 void initialize_misc();
574
575 void initialize(CompiledMethod* nm, address begin, address limit);
576
577 RelocIterator() { initialize_misc(); }
578
579 public:
580 // constructor
581 RelocIterator(CompiledMethod* nm, address begin = NULL, address limit = NULL);
582 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL);
583
584 // get next reloc info, return !eos
585 bool next() {
586 _current++;
587 assert(_current <= _end, "must not overrun relocInfo");
588 if (_current == _end) {
589 set_has_current(false);
590 return false;
591 }
592 set_has_current(true);
593
594 if (_current->is_prefix()) {
595 advance_over_prefix();
596 assert(!current()->is_prefix(), "only one prefix at a time");
597 }
598
599 _addr += _current->addr_offset();
600
601 if (_limit != NULL && _addr >= _limit) {
602 set_has_current(false);
603 return false;
604 }
605
606 if (relocInfo::have_format) _format = current()->format();
607 return true;
608 }
609
610 // accessors
611 address limit() const { return _limit; }
612 void set_limit(address x);
613 relocType type() const { return current()->type(); }
614 int format() const { return (relocInfo::have_format) ? current()->format() : 0; }
615 address addr() const { return _addr; }
616 CompiledMethod* code() const { return _code; }
617 nmethod* code_as_nmethod() const;
618 short* data() const { return _data; }
619 int datalen() const { return _datalen; }
620 bool has_current() const { return _datalen >= 0; }
621
622 void set_addr(address addr) { _addr = addr; }
623 bool addr_in_const() const;
624
625 address section_start(int n) const {
626 assert(_section_start[n], "must be initialized");
627 return _section_start[n];
628 }
629 address section_end(int n) const {
630 assert(_section_end[n], "must be initialized");
631 return _section_end[n];
632 }
633
634 // The address points to the affected displacement part of the instruction.
635 // For RISC, this is just the whole instruction.
636 // For Intel, this is an unaligned 32-bit word.
637
638 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc.
639 #define EACH_TYPE(name) \
640 inline name##_Relocation* name##_reloc();
641 APPLY_TO_RELOCATIONS(EACH_TYPE)
642 #undef EACH_TYPE
643 // generic relocation accessor; switches on type to call the above
644 Relocation* reloc();
645
646 // CodeBlob's have relocation indexes for faster random access:
647 static int locs_and_index_size(int code_size, int locs_size);
648 // Store an index into [dest_start+dest_count..dest_end).
649 // At dest_start[0..dest_count] is the actual relocation information.
650 // Everything else up to dest_end is free space for the index.
651 static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end);
652
653 #ifndef PRODUCT
654 public:
655 void print();
656 void print_current();
657 #endif
658 };
659
660
661 // A Relocation is a flyweight object allocated within a RelocationHolder.
662 // It represents the relocation data of relocation record.
663 // So, the RelocIterator unpacks relocInfos into Relocations.
664
665 class Relocation VALUE_OBJ_CLASS_SPEC {
666 friend class RelocationHolder;
667 friend class RelocIterator;
668
669 private:
670 static void guarantee_size();
671
672 // When a relocation has been created by a RelocIterator,
673 // this field is non-null. It allows the relocation to know
674 // its context, such as the address to which it applies.
675 RelocIterator* _binding;
676
677 protected:
678 RelocIterator* binding() const {
679 assert(_binding != NULL, "must be bound");
680 return _binding;
681 }
682 void set_binding(RelocIterator* b) {
683 assert(_binding == NULL, "must be unbound");
684 _binding = b;
685 assert(_binding != NULL, "must now be bound");
686 }
687
688 Relocation() {
689 _binding = NULL;
690 }
691
692 static RelocationHolder newHolder() {
693 return RelocationHolder();
694 }
695
696 public:
697 void* operator new(size_t size, const RelocationHolder& holder) throw() {
698 if (size > sizeof(holder._relocbuf)) guarantee_size();
699 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree");
700 return holder.reloc();
701 }
702
703 // make a generic relocation for a given type (if possible)
704 static RelocationHolder spec_simple(relocInfo::relocType rtype);
705
706 // here is the type-specific hook which writes relocation data:
707 virtual void pack_data_to(CodeSection* dest) { }
708
709 // here is the type-specific hook which reads (unpacks) relocation data:
710 virtual void unpack_data() {
711 assert(datalen()==0 || type()==relocInfo::none, "no data here");
712 }
713
714 protected:
715 // Helper functions for pack_data_to() and unpack_data().
716
717 // Most of the compression logic is confined here.
718 // (The "immediate data" mechanism of relocInfo works independently
719 // of this stuff, and acts to further compress most 1-word data prefixes.)
720
721 // A variable-width int is encoded as a short if it will fit in 16 bits.
722 // The decoder looks at datalen to decide whether to unpack short or jint.
723 // Most relocation records are quite simple, containing at most two ints.
724
725 static bool is_short(jint x) { return x == (short)x; }
726 static short* add_short(short* p, int x) { *p++ = x; return p; }
727 static short* add_jint (short* p, jint x) {
728 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x);
729 return p;
730 }
731 static short* add_var_int(short* p, jint x) { // add a variable-width int
732 if (is_short(x)) p = add_short(p, x);
733 else p = add_jint (p, x);
734 return p;
735 }
736
737 static short* pack_1_int_to(short* p, jint x0) {
738 // Format is one of: [] [x] [Xx]
739 if (x0 != 0) p = add_var_int(p, x0);
740 return p;
741 }
742 int unpack_1_int() {
743 assert(datalen() <= 2, "too much data");
744 return relocInfo::jint_data_at(0, data(), datalen());
745 }
746
747 // With two ints, the short form is used only if both ints are short.
748 short* pack_2_ints_to(short* p, jint x0, jint x1) {
749 // Format is one of: [] [x y?] [Xx Y?y]
750 if (x0 == 0 && x1 == 0) {
751 // no halfwords needed to store zeroes
752 } else if (is_short(x0) && is_short(x1)) {
753 // 1-2 halfwords needed to store shorts
754 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1);
755 } else {
756 // 3-4 halfwords needed to store jints
757 p = add_jint(p, x0); p = add_var_int(p, x1);
758 }
759 return p;
760 }
761 void unpack_2_ints(jint& x0, jint& x1) {
762 int dlen = datalen();
763 short* dp = data();
764 if (dlen <= 2) {
765 x0 = relocInfo::short_data_at(0, dp, dlen);
766 x1 = relocInfo::short_data_at(1, dp, dlen);
767 } else {
768 assert(dlen <= 4, "too much data");
769 x0 = relocInfo::jint_data_at(0, dp, dlen);
770 x1 = relocInfo::jint_data_at(2, dp, dlen);
771 }
772 }
773
774 protected:
775 // platform-independent utility for patching constant section
776 void const_set_data_value (address x);
777 void const_verify_data_value (address x);
778 // platform-dependent utilities for decoding and patching instructions
779 void pd_set_data_value (address x, intptr_t off, bool verify_only = false); // a set or mem-ref
780 void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); }
781 address pd_call_destination (address orig_addr = NULL);
782 void pd_set_call_destination (address x);
783
784 // this extracts the address of an address in the code stream instead of the reloc data
785 address* pd_address_in_code ();
786
787 // this extracts an address from the code stream instead of the reloc data
788 address pd_get_address_from_code ();
789
790 // these convert from byte offsets, to scaled offsets, to addresses
791 static jint scaled_offset(address x, address base) {
792 int byte_offset = x - base;
793 int offset = -byte_offset / relocInfo::addr_unit();
794 assert(address_from_scaled_offset(offset, base) == x, "just checkin'");
795 return offset;
796 }
797 static jint scaled_offset_null_special(address x, address base) {
798 // Some relocations treat offset=0 as meaning NULL.
799 // Handle this extra convention carefully.
800 if (x == NULL) return 0;
801 assert(x != base, "offset must not be zero");
802 return scaled_offset(x, base);
803 }
804 static address address_from_scaled_offset(jint offset, address base) {
805 int byte_offset = -( offset * relocInfo::addr_unit() );
806 return base + byte_offset;
807 }
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 CompiledMethod* code() const { return binding()->code(); }
818 nmethod* code_as_nmethod() const { return binding()->code_as_nmethod(); }
819 bool addr_in_const() const { return binding()->addr_in_const(); }
820 protected:
821 short* data() const { return binding()->data(); }
822 int datalen() const { return binding()->datalen(); }
823 int format() const { return binding()->format(); }
824
825 public:
826 virtual relocInfo::relocType type() { return relocInfo::none; }
827
828 // is it a call instruction?
829 virtual bool is_call() { return false; }
830
831 // is it a data movement instruction?
832 virtual bool is_data() { return false; }
833
834 // some relocations can compute their own values
835 virtual address value();
836
837 // all relocations are able to reassert their values
838 virtual void set_value(address x);
839
840 virtual void clear_inline_cache() { }
841
842 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and
843 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is
844 // probably a reasonable assumption, since empty caches simplifies code reloacation.
845 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { }
846
847 void print();
848 };
849
850
851 // certain inlines must be deferred until class Relocation is defined:
852
853 inline RelocationHolder::RelocationHolder() {
854 // initialize the vtbl, just to keep things type-safe
855 new(*this) Relocation();
856 }
857
858
859 inline RelocationHolder::RelocationHolder(Relocation* r) {
860 // wordwise copy from r (ok if it copies garbage after r)
861 for (int i = 0; i < _relocbuf_size; i++) {
862 _relocbuf[i] = ((void**)r)[i];
863 }
864 }
865
866
867 relocInfo::relocType RelocationHolder::type() const {
868 return reloc()->type();
869 }
870
871 // A DataRelocation always points at a memory or load-constant instruction..
872 // It is absolute on most machines, and the constant is split on RISCs.
873 // The specific subtypes are oop, external_word, and internal_word.
874 // By convention, the "value" does not include a separately reckoned "offset".
875 class DataRelocation : public Relocation {
876 public:
877 bool is_data() { return true; }
878
879 // both target and offset must be computed somehow from relocation data
880 virtual int offset() { return 0; }
881 address value() = 0;
882 void set_value(address x) { set_value(x, offset()); }
883 void set_value(address x, intptr_t o) {
884 if (addr_in_const())
885 const_set_data_value(x);
886 else
887 pd_set_data_value(x, o);
888 }
889 void verify_value(address x) {
890 if (addr_in_const())
891 const_verify_data_value(x);
892 else
893 pd_verify_data_value(x, offset());
894 }
895
896 // The "o" (displacement) argument is relevant only to split relocations
897 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns
898 // can encode more than 32 bits between them. This allows compilers to
899 // share set-hi instructions between addresses that differ by a small
900 // offset (e.g., different static variables in the same class).
901 // On such machines, the "x" argument to set_value on all set-lo
902 // instructions must be the same as the "x" argument for the
903 // corresponding set-hi instructions. The "o" arguments for the
904 // set-hi instructions are ignored, and must not affect the high-half
905 // immediate constant. The "o" arguments for the set-lo instructions are
906 // added into the low-half immediate constant, and must not overflow it.
907 };
908
909 // A CallRelocation always points at a call instruction.
910 // It is PC-relative on most machines.
911 class CallRelocation : public Relocation {
912 public:
913 bool is_call() { return true; }
914
915 address destination() { return pd_call_destination(); }
916 void set_destination(address x); // pd_set_call_destination
917
918 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
919 address value() { return destination(); }
920 void set_value(address x) { set_destination(x); }
921 };
922
923 class oop_Relocation : public DataRelocation {
924 relocInfo::relocType type() { return relocInfo::oop_type; }
925
926 public:
927 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll]
928 // an oop in the CodeBlob's oop pool
929 static RelocationHolder spec(int oop_index, int offset = 0) {
930 assert(oop_index > 0, "must be a pool-resident oop");
931 RelocationHolder rh = newHolder();
932 new(rh) oop_Relocation(oop_index, offset);
933 return rh;
934 }
935 // an oop in the instruction stream
936 static RelocationHolder spec_for_immediate() {
937 const int oop_index = 0;
938 const int offset = 0; // if you want an offset, use the oop pool
939 RelocationHolder rh = newHolder();
940 new(rh) oop_Relocation(oop_index, offset);
941 return rh;
942 }
943
944 private:
945 jint _oop_index; // if > 0, index into CodeBlob::oop_at
946 jint _offset; // byte offset to apply to the oop itself
947
948 oop_Relocation(int oop_index, int offset) {
949 _oop_index = oop_index; _offset = offset;
950 }
951
952 friend class RelocIterator;
953 oop_Relocation() { }
954
955 public:
956 int oop_index() { return _oop_index; }
957 int offset() { return _offset; }
958
959 // data is packed in "2_ints" format: [i o] or [Ii Oo]
960 void pack_data_to(CodeSection* dest);
961 void unpack_data();
962
963 void fix_oop_relocation(); // reasserts oop value
964
965 void verify_oop_relocation();
966
967 address value() { return (address) *oop_addr(); }
968
969 bool oop_is_immediate() { return oop_index() == 0; }
970
971 oop* oop_addr(); // addr or &pool[jint_data]
972 oop oop_value(); // *oop_addr
973 // Note: oop_value transparently converts Universe::non_oop_word to NULL.
974 };
975
976
977 // copy of oop_Relocation for now but may delete stuff in both/either
978 class metadata_Relocation : public DataRelocation {
979 relocInfo::relocType type() { return relocInfo::metadata_type; }
980
981 public:
982 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll]
983 // an metadata in the CodeBlob's metadata pool
984 static RelocationHolder spec(int metadata_index, int offset = 0) {
985 assert(metadata_index > 0, "must be a pool-resident metadata");
986 RelocationHolder rh = newHolder();
987 new(rh) metadata_Relocation(metadata_index, offset);
988 return rh;
989 }
990 // an metadata in the instruction stream
991 static RelocationHolder spec_for_immediate() {
992 const int metadata_index = 0;
993 const int offset = 0; // if you want an offset, use the metadata pool
994 RelocationHolder rh = newHolder();
995 new(rh) metadata_Relocation(metadata_index, offset);
996 return rh;
997 }
998
999 private:
1000 jint _metadata_index; // if > 0, index into nmethod::metadata_at
1001 jint _offset; // byte offset to apply to the metadata itself
1002
1003 metadata_Relocation(int metadata_index, int offset) {
1004 _metadata_index = metadata_index; _offset = offset;
1005 }
1006
1007 friend class RelocIterator;
1008 metadata_Relocation() { }
1009
1010 // Fixes a Metadata pointer in the code. Most platforms embeds the
1011 // Metadata pointer in the code at compile time so this is empty
1012 // for them.
1013 void pd_fix_value(address x);
1014
1015 public:
1016 int metadata_index() { return _metadata_index; }
1017 int offset() { return _offset; }
1018
1019 // data is packed in "2_ints" format: [i o] or [Ii Oo]
1020 void pack_data_to(CodeSection* dest);
1021 void unpack_data();
1022
1023 void fix_metadata_relocation(); // reasserts metadata value
1024
1025 void verify_metadata_relocation();
1026
1027 address value() { return (address) *metadata_addr(); }
1028
1029 bool metadata_is_immediate() { return metadata_index() == 0; }
1030
1031 Metadata** metadata_addr(); // addr or &pool[jint_data]
1032 Metadata* metadata_value(); // *metadata_addr
1033 // Note: metadata_value transparently converts Universe::non_metadata_word to NULL.
1034 };
1035
1036
1037 class virtual_call_Relocation : public CallRelocation {
1038 relocInfo::relocType type() { return relocInfo::virtual_call_type; }
1039
1040 public:
1041 // "cached_value" points to the first associated set-oop.
1042 // The oop_limit helps find the last associated set-oop.
1043 // (See comments at the top of this file.)
1044 static RelocationHolder spec(address cached_value, jint method_index = 0) {
1045 RelocationHolder rh = newHolder();
1046 new(rh) virtual_call_Relocation(cached_value, method_index);
1047 return rh;
1048 }
1049
1050 private:
1051 address _cached_value; // location of set-value instruction
1052 jint _method_index; // resolved method for a Java call
1053
1054 virtual_call_Relocation(address cached_value, int method_index) {
1055 _cached_value = cached_value;
1056 _method_index = method_index;
1057 assert(cached_value != NULL, "first oop address must be specified");
1058 }
1059
1060 friend class RelocIterator;
1061 virtual_call_Relocation() { }
1062
1063 public:
1064 address cached_value();
1065
1066 int method_index() { return _method_index; }
1067 Method* method_value();
1068
1069 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll]
1070 // oop_limit is set to 0 if the limit falls somewhere within the call.
1071 // When unpacking, a zero oop_limit is taken to refer to the end of the call.
1072 // (This has the effect of bringing in the call's delay slot on SPARC.)
1073 void pack_data_to(CodeSection* dest);
1074 void unpack_data();
1075
1076 void clear_inline_cache();
1077 };
1078
1079
1080 class opt_virtual_call_Relocation : public CallRelocation {
1081 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; }
1082
1083 public:
1084 static RelocationHolder spec(int method_index = 0) {
1085 RelocationHolder rh = newHolder();
1086 new(rh) opt_virtual_call_Relocation(method_index);
1087 return rh;
1088 }
1089
1090 private:
1091 jint _method_index; // resolved method for a Java call
1092
1093 opt_virtual_call_Relocation(int method_index) {
1094 _method_index = method_index;
1095 }
1096
1097 friend class RelocIterator;
1098 opt_virtual_call_Relocation() {}
1099
1100 public:
1101 int method_index() { return _method_index; }
1102 Method* method_value();
1103
1104 void pack_data_to(CodeSection* dest);
1105 void unpack_data();
1106
1107 void clear_inline_cache();
1108
1109 // find the matching static_stub
1110 address static_stub();
1111 };
1112
1113
1114 class static_call_Relocation : public CallRelocation {
1115 relocInfo::relocType type() { return relocInfo::static_call_type; }
1116
1117 public:
1118 static RelocationHolder spec(int method_index = 0) {
1119 RelocationHolder rh = newHolder();
1120 new(rh) static_call_Relocation(method_index);
1121 return rh;
1122 }
1123
1124 private:
1125 jint _method_index; // resolved method for a Java call
1126
1127 static_call_Relocation(int method_index) {
1128 _method_index = method_index;
1129 }
1130
1131 friend class RelocIterator;
1132 static_call_Relocation() {}
1133
1134 public:
1135 int method_index() { return _method_index; }
1136 Method* method_value();
1137
1138 void pack_data_to(CodeSection* dest);
1139 void unpack_data();
1140
1141 void clear_inline_cache();
1142
1143 // find the matching static_stub
1144 address static_stub();
1145 };
1146
1147 class static_stub_Relocation : public Relocation {
1148 relocInfo::relocType type() { return relocInfo::static_stub_type; }
1149
1150 public:
1151 static RelocationHolder spec(address static_call) {
1152 RelocationHolder rh = newHolder();
1153 new(rh) static_stub_Relocation(static_call);
1154 return rh;
1155 }
1156
1157 private:
1158 address _static_call; // location of corresponding static_call
1159
1160 static_stub_Relocation(address static_call) {
1161 _static_call = static_call;
1162 }
1163
1164 friend class RelocIterator;
1165 static_stub_Relocation() { }
1166
1167 public:
1168 void clear_inline_cache();
1169
1170 address static_call() { return _static_call; }
1171
1172 // data is packed as a scaled offset in "1_int" format: [c] or [Cc]
1173 void pack_data_to(CodeSection* dest);
1174 void unpack_data();
1175 };
1176
1177 class runtime_call_Relocation : public CallRelocation {
1178 relocInfo::relocType type() { return relocInfo::runtime_call_type; }
1179
1180 public:
1181 static RelocationHolder spec() {
1182 RelocationHolder rh = newHolder();
1183 new(rh) runtime_call_Relocation();
1184 return rh;
1185 }
1186
1187 private:
1188 friend class RelocIterator;
1189 runtime_call_Relocation() { }
1190
1191 public:
1192 };
1193
1194 // Trampoline Relocations.
1195 // A trampoline allows to encode a small branch in the code, even if there
1196 // is the chance that this branch can not reach all possible code locations.
1197 // If the relocation finds that a branch is too far for the instruction
1198 // in the code, it can patch it to jump to the trampoline where is
1199 // sufficient space for a far branch. Needed on PPC.
1200 class trampoline_stub_Relocation : public Relocation {
1201 relocInfo::relocType type() { return relocInfo::trampoline_stub_type; }
1202
1203 public:
1204 static RelocationHolder spec(address static_call) {
1205 RelocationHolder rh = newHolder();
1206 return (new (rh) trampoline_stub_Relocation(static_call));
1207 }
1208
1209 private:
1210 address _owner; // Address of the NativeCall that owns the trampoline.
1211
1212 trampoline_stub_Relocation(address owner) {
1213 _owner = owner;
1214 }
1215
1216 friend class RelocIterator;
1217 trampoline_stub_Relocation() { }
1218
1219 public:
1220
1221 // Return the address of the NativeCall that owns the trampoline.
1222 address owner() { return _owner; }
1223
1224 void pack_data_to(CodeSection * dest);
1225 void unpack_data();
1226
1227 // Find the trampoline stub for a call.
1228 static address get_trampoline_for(address call, nmethod* code);
1229 };
1230
1231 class external_word_Relocation : public DataRelocation {
1232 relocInfo::relocType type() { return relocInfo::external_word_type; }
1233
1234 public:
1235 static RelocationHolder spec(address target) {
1236 assert(target != NULL, "must not be null");
1237 RelocationHolder rh = newHolder();
1238 new(rh) external_word_Relocation(target);
1239 return rh;
1240 }
1241
1242 // Use this one where all 32/64 bits of the target live in the code stream.
1243 // The target must be an intptr_t, and must be absolute (not relative).
1244 static RelocationHolder spec_for_immediate() {
1245 RelocationHolder rh = newHolder();
1246 new(rh) external_word_Relocation(NULL);
1247 return rh;
1248 }
1249
1250 // Some address looking values aren't safe to treat as relocations
1251 // and should just be treated as constants.
1252 static bool can_be_relocated(address target) {
1253 assert(target == NULL || (uintptr_t)target >= (uintptr_t)os::vm_page_size(), INTPTR_FORMAT, (intptr_t)target);
1254 return target != NULL;
1255 }
1256
1257 private:
1258 address _target; // address in runtime
1259
1260 external_word_Relocation(address target) {
1261 _target = target;
1262 }
1263
1264 friend class RelocIterator;
1265 external_word_Relocation() { }
1266
1267 public:
1268 // data is packed as a well-known address in "1_int" format: [a] or [Aa]
1269 // The function runtime_address_to_index is used to turn full addresses
1270 // to short indexes, if they are pre-registered by the stub mechanism.
1271 // If the "a" value is 0 (i.e., _target is NULL), the address is stored
1272 // in the code stream. See external_word_Relocation::target().
1273 void pack_data_to(CodeSection* dest);
1274 void unpack_data();
1275
1276 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1277 address target(); // if _target==NULL, fetch addr from code stream
1278 address value() { return target(); }
1279 };
1280
1281 class internal_word_Relocation : public DataRelocation {
1282 relocInfo::relocType type() { return relocInfo::internal_word_type; }
1283
1284 public:
1285 static RelocationHolder spec(address target) {
1286 assert(target != NULL, "must not be null");
1287 RelocationHolder rh = newHolder();
1288 new(rh) internal_word_Relocation(target);
1289 return rh;
1290 }
1291
1292 // use this one where all the bits of the target can fit in the code stream:
1293 static RelocationHolder spec_for_immediate() {
1294 RelocationHolder rh = newHolder();
1295 new(rh) internal_word_Relocation(NULL);
1296 return rh;
1297 }
1298
1299 internal_word_Relocation(address target) {
1300 _target = target;
1301 _section = -1; // self-relative
1302 }
1303
1304 protected:
1305 address _target; // address in CodeBlob
1306 int _section; // section providing base address, if any
1307
1308 friend class RelocIterator;
1309 internal_word_Relocation() { }
1310
1311 // bit-width of LSB field in packed offset, if section >= 0
1312 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits
1313
1314 public:
1315 // data is packed as a scaled offset in "1_int" format: [o] or [Oo]
1316 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored
1317 // in the code stream. See internal_word_Relocation::target().
1318 // If _section is not -1, it is appended to the low bits of the offset.
1319 void pack_data_to(CodeSection* dest);
1320 void unpack_data();
1321
1322 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1323 address target(); // if _target==NULL, fetch addr from code stream
1324 int section() { return _section; }
1325 address value() { return target(); }
1326 };
1327
1328 class section_word_Relocation : public internal_word_Relocation {
1329 relocInfo::relocType type() { return relocInfo::section_word_type; }
1330
1331 public:
1332 static RelocationHolder spec(address target, int section) {
1333 RelocationHolder rh = newHolder();
1334 new(rh) section_word_Relocation(target, section);
1335 return rh;
1336 }
1337
1338 section_word_Relocation(address target, int section) {
1339 assert(target != NULL, "must not be null");
1340 assert(section >= 0, "must be a valid section");
1341 _target = target;
1342 _section = section;
1343 }
1344
1345 //void pack_data_to -- inherited
1346 void unpack_data();
1347
1348 private:
1349 friend class RelocIterator;
1350 section_word_Relocation() { }
1351 };
1352
1353
1354 class poll_Relocation : public Relocation {
1355 bool is_data() { return true; }
1356 relocInfo::relocType type() { return relocInfo::poll_type; }
1357 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1358 };
1359
1360 class poll_return_Relocation : public poll_Relocation {
1361 relocInfo::relocType type() { return relocInfo::poll_return_type; }
1362 };
1363
1364 // We know all the xxx_Relocation classes, so now we can define these:
1365 #define EACH_CASE(name) \
1366 inline name##_Relocation* RelocIterator::name##_reloc() { \
1367 assert(type() == relocInfo::name##_type, "type must agree"); \
1368 /* The purpose of the placed "new" is to re-use the same */ \
1369 /* stack storage for each new iteration. */ \
1370 name##_Relocation* r = new(_rh) name##_Relocation(); \
1371 r->set_binding(this); \
1372 r->name##_Relocation::unpack_data(); \
1373 return r; \
1374 }
1375 APPLY_TO_RELOCATIONS(EACH_CASE);
1376 #undef EACH_CASE
1377
1378 inline RelocIterator::RelocIterator(CompiledMethod* nm, address begin, address limit) {
1379 initialize(nm, begin, limit);
1380 }
1381
1382 #endif // SHARE_VM_CODE_RELOCINFO_HPP