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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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 #include "utilities/macros.hpp"
31
32 class nmethod;
33 class CompiledMethod;
34 class Metadata;
35 class NativeMovConstReg;
36
37 // Types in this file:
38 // relocInfo
39 // One element of an array of halfwords encoding compressed relocations.
40 // Also, the source of relocation types (relocInfo::oop_type, ...).
41 // Relocation
42 // A flyweight object representing a single relocation.
43 // It is fully unpacked from the compressed relocation array.
44 // metadata_Relocation, ... (subclasses of Relocation)
45 // The location of some type-specific operations (metadata_addr, ...).
46 // Also, the source of relocation specs (metadata_Relocation::spec, ...).
47 // oop_Relocation, ... (subclasses of Relocation)
48 // oops in the code stream (strings, class loaders)
49 // Also, the source of relocation specs (oop_Relocation::spec, ...).
50 // RelocationHolder
51 // A ValueObj type which acts as a union holding a Relocation object.
52 // Represents a relocation spec passed into a CodeBuffer during assembly.
53 // RelocIterator
54 // A StackObj which iterates over the relocations associated with
55 // a range of code addresses. Can be used to operate a copy of code.
56 // BoundRelocation
57 // An _internal_ type shared by packers and unpackers of relocations.
58 // It pastes together a RelocationHolder with some pointers into
59 // code and relocInfo streams.
60
61
62 // Notes on relocType:
63 //
64 // These hold enough information to read or write a value embedded in
65 // the instructions of an CodeBlob. They're used to update:
66 //
67 // 1) embedded oops (isOop() == true)
68 // 2) inline caches (isIC() == true)
69 // 3) runtime calls (isRuntimeCall() == true)
70 // 4) internal word ref (isInternalWord() == true)
71 // 5) external word ref (isExternalWord() == true)
72 //
73 // when objects move (GC) or if code moves (compacting the code heap).
74 // They are also used to patch the code (if a call site must change)
75 //
76 // A relocInfo is represented in 16 bits:
77 // 4 bits indicating the relocation type
78 // 12 bits indicating the offset from the previous relocInfo address
79 //
80 // The offsets accumulate along the relocInfo stream to encode the
81 // address within the CodeBlob, which is named RelocIterator::addr().
82 // The address of a particular relocInfo always points to the first
83 // byte of the relevant instruction (and not to any of its subfields
84 // or embedded immediate constants).
85 //
86 // The offset value is scaled appropriately for the target machine.
87 // (See relocInfo_<arch>.hpp for the offset scaling.)
88 //
89 // On some machines, there may also be a "format" field which may provide
90 // additional information about the format of the instruction stream
91 // at the corresponding code address. The format value is usually zero.
92 // Any machine (such as Intel) whose instructions can sometimes contain
93 // more than one relocatable constant needs format codes to distinguish
94 // which operand goes with a given relocation.
95 //
96 // If the target machine needs N format bits, the offset has 12-N bits,
97 // the format is encoded between the offset and the type, and the
98 // relocInfo_<arch>.hpp file has manifest constants for the format codes.
99 //
100 // If the type is "data_prefix_tag" then the offset bits are further encoded,
101 // and in fact represent not a code-stream offset but some inline data.
102 // The data takes the form of a counted sequence of halfwords, which
103 // precedes the actual relocation record. (Clients never see it directly.)
104 // The interpetation of this extra data depends on the relocation type.
105 //
106 // On machines that have 32-bit immediate fields, there is usually
107 // little need for relocation "prefix" data, because the instruction stream
108 // is a perfectly reasonable place to store the value. On machines in
109 // which 32-bit values must be "split" across instructions, the relocation
110 // data is the "true" specification of the value, which is then applied
111 // to some field of the instruction (22 or 13 bits, on SPARC).
112 //
113 // Whenever the location of the CodeBlob changes, any PC-relative
114 // relocations, and any internal_word_type relocations, must be reapplied.
115 // After the GC runs, oop_type relocations must be reapplied.
116 //
117 //
118 // Here are meanings of the types:
119 //
120 // relocInfo::none -- a filler record
121 // Value: none
122 // Instruction: The corresponding code address is ignored
123 // Data: Any data prefix and format code are ignored
124 // (This means that any relocInfo can be disabled by setting
125 // its type to none. See relocInfo::remove.)
126 //
127 // relocInfo::oop_type, relocInfo::metadata_type -- a reference to an oop or meta data
128 // Value: an oop, or else the address (handle) of an oop
129 // Instruction types: memory (load), set (load address)
130 // Data: [] an oop stored in 4 bytes of instruction
131 // [n] n is the index of an oop in the CodeBlob's oop pool
132 // [[N]n l] and l is a byte offset to be applied to the oop
133 // [Nn Ll] both index and offset may be 32 bits if necessary
134 // Here is a special hack, used only by the old compiler:
135 // [[N]n 00] the value is the __address__ of the nth oop in the pool
136 // (Note that the offset allows optimal references to class variables.)
137 //
138 // relocInfo::internal_word_type -- an address within the same CodeBlob
139 // relocInfo::section_word_type -- same, but can refer to another section
140 // Value: an address in the CodeBlob's code or constants section
141 // Instruction types: memory (load), set (load address)
142 // Data: [] stored in 4 bytes of instruction
143 // [[L]l] a relative offset (see [About Offsets] below)
144 // In the case of section_word_type, the offset is relative to a section
145 // base address, and the section number (e.g., SECT_INSTS) is encoded
146 // into the low two bits of the offset L.
147 //
148 // relocInfo::external_word_type -- a fixed address in the runtime system
149 // Value: an address
150 // Instruction types: memory (load), set (load address)
151 // Data: [] stored in 4 bytes of instruction
152 // [n] the index of a "well-known" stub (usual case on RISC)
153 // [Ll] a 32-bit address
154 //
155 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system
156 // Value: an address
157 // Instruction types: PC-relative call (or a PC-relative branch)
158 // Data: [] stored in 4 bytes of instruction
159 //
160 // relocInfo::static_call_type -- a static call
161 // Value: an CodeBlob, a stub, or a fixup routine
162 // Instruction types: a call
163 // Data: []
164 // The identity of the callee is extracted from debugging information.
165 // //%note reloc_3
166 //
167 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline
168 // cache)
169 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine
170 // Instruction types: a call, plus some associated set-oop instructions
171 // Data: [] the associated set-oops are adjacent to the call
172 // [n] n is a relative offset to the first set-oop
173 // [[N]n l] and l is a limit within which the set-oops occur
174 // [Nn Ll] both n and l may be 32 bits if necessary
175 // The identity of the callee is extracted from debugging information.
176 //
177 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound
178 //
179 // Same info as a static_call_type. We use a special type, so the handling of
180 // virtuals and statics are separated.
181 //
182 //
183 // The offset n points to the first set-oop. (See [About Offsets] below.)
184 // In turn, the set-oop instruction specifies or contains an oop cell devoted
185 // exclusively to the IC call, which can be patched along with the call.
186 //
187 // The locations of any other set-oops are found by searching the relocation
188 // information starting at the first set-oop, and continuing until all
189 // relocations up through l have been inspected. The value l is another
190 // relative offset. (Both n and l are relative to the call's first byte.)
191 //
192 // The limit l of the search is exclusive. However, if it points within
193 // the call (e.g., offset zero), it is adjusted to point after the call and
194 // any associated machine-specific delay slot.
195 //
196 // Since the offsets could be as wide as 32-bits, these conventions
197 // put no restrictions whatever upon code reorganization.
198 //
199 // The compiler is responsible for ensuring that transition from a clean
200 // state to a monomorphic compiled state is MP-safe. This implies that
201 // the system must respond well to intermediate states where a random
202 // subset of the set-oops has been correctly from the clean state
203 // upon entry to the VEP of the compiled method. In the case of a
204 // machine (Intel) with a single set-oop instruction, the 32-bit
205 // immediate field must not straddle a unit of memory coherence.
206 // //%note reloc_3
207 //
208 // relocInfo::static_stub_type -- an extra stub for each static_call_type
209 // Value: none
210 // Instruction types: a virtual call: { set_oop; jump; }
211 // Data: [[N]n] the offset of the associated static_call reloc
212 // This stub becomes the target of a static call which must be upgraded
213 // to a virtual call (because the callee is interpreted).
214 // See [About Offsets] below.
215 // //%note reloc_2
216 //
217 // relocInfo::poll_[return_]type -- a safepoint poll
218 // Value: none
219 // Instruction types: memory load or test
220 // Data: none
221 //
222 // For example:
223 //
224 // INSTRUCTIONS RELOC: TYPE PREFIX DATA
225 // ------------ ---- -----------
226 // sethi %hi(myObject), R oop_type [n(myObject)]
227 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset]
228 // add R2, 1, R2
229 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset]
230 //%note reloc_1
231 //
232 // This uses 4 instruction words, 8 relocation halfwords,
233 // and an entry (which is sharable) in the CodeBlob's oop pool,
234 // for a total of 36 bytes.
235 //
236 // Note that the compiler is responsible for ensuring the "fldOffset" when
237 // added to "%lo(myObject)" does not overflow the immediate fields of the
238 // memory instructions.
239 //
240 //
241 // [About Offsets] Relative offsets are supplied to this module as
242 // positive byte offsets, but they may be internally stored scaled
243 // and/or negated, depending on what is most compact for the target
244 // system. Since the object pointed to by the offset typically
245 // precedes the relocation address, it is profitable to store
246 // these negative offsets as positive numbers, but this decision
247 // is internal to the relocation information abstractions.
248 //
249
250 class Relocation;
251 class CodeBuffer;
252 class CodeSection;
253 class RelocIterator;
254
255 class relocInfo VALUE_OBJ_CLASS_SPEC {
256 friend class RelocIterator;
257 public:
258 enum relocType {
259 none = 0, // Used when no relocation should be generated
260 oop_type = 1, // embedded oop
261 virtual_call_type = 2, // a standard inline cache call for a virtual send
262 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache)
263 static_call_type = 4, // a static send
264 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case)
265 runtime_call_type = 6, // call to fixed external routine
266 external_word_type = 7, // reference to fixed external address
267 internal_word_type = 8, // reference within the current code blob
268 section_word_type = 9, // internal, but a cross-section reference
269 poll_type = 10, // polling instruction for safepoints
270 poll_return_type = 11, // polling instruction for safepoints at return
271 metadata_type = 12, // metadata that used to be oops
272 trampoline_stub_type = 13, // stub-entry for trampoline
273 runtime_call_w_cp_type = 14, // Runtime call which may load its target from the constant pool
274 data_prefix_tag = 15, // tag for a prefix (carries data arguments)
275 type_mask = 15 // A mask which selects only the above values
276 };
277
278 protected:
279 unsigned short _value;
280
281 enum RawBitsToken { RAW_BITS };
282 relocInfo(relocType type, RawBitsToken ignore, int bits)
283 : _value((type << nontype_width) + bits) { }
284
285 relocInfo(relocType type, RawBitsToken ignore, int off, int f)
286 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { }
287
288 public:
289 // constructor
290 relocInfo(relocType type, int offset, int format = 0)
291 #ifndef ASSERT
292 {
293 (*this) = relocInfo(type, RAW_BITS, offset, format);
294 }
295 #else
296 // Put a bunch of assertions out-of-line.
297 ;
298 #endif
299
300 #define APPLY_TO_RELOCATIONS(visitor) \
301 visitor(oop) \
302 visitor(metadata) \
303 visitor(virtual_call) \
304 visitor(opt_virtual_call) \
305 visitor(static_call) \
306 visitor(static_stub) \
307 visitor(runtime_call) \
308 visitor(runtime_call_w_cp) \
309 visitor(external_word) \
310 visitor(internal_word) \
311 visitor(poll) \
312 visitor(poll_return) \
313 visitor(section_word) \
314 visitor(trampoline_stub) \
315
316
317 public:
318 enum {
319 value_width = sizeof(unsigned short) * BitsPerByte,
320 type_width = 4, // == log2(type_mask+1)
321 nontype_width = value_width - type_width,
322 datalen_width = nontype_width-1,
323 datalen_tag = 1 << datalen_width, // or-ed into _value
324 datalen_limit = 1 << datalen_width,
325 datalen_mask = (1 << datalen_width)-1
326 };
327
328 // accessors
329 public:
330 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); }
331 int format() const { return format_mask==0? 0: format_mask &
332 ((unsigned)_value >> offset_width); }
333 int addr_offset() const { assert(!is_prefix(), "must have offset");
334 return (_value & offset_mask)*offset_unit; }
335
336 protected:
337 const short* data() const { assert(is_datalen(), "must have data");
338 return (const short*)(this + 1); }
339 int datalen() const { assert(is_datalen(), "must have data");
340 return (_value & datalen_mask); }
341 int immediate() const { assert(is_immediate(), "must have immed");
342 return (_value & datalen_mask); }
343 public:
344 static int addr_unit() { return offset_unit; }
345 static int offset_limit() { return (1 << offset_width) * offset_unit; }
346
347 void set_type(relocType type);
348 void set_format(int format);
349
350 void remove() { set_type(none); }
351
352 protected:
353 bool is_none() const { return type() == none; }
354 bool is_prefix() const { return type() == data_prefix_tag; }
355 bool is_datalen() const { assert(is_prefix(), "must be prefix");
356 return (_value & datalen_tag) != 0; }
357 bool is_immediate() const { assert(is_prefix(), "must be prefix");
358 return (_value & datalen_tag) == 0; }
359
360 public:
361 // Occasionally records of type relocInfo::none will appear in the stream.
362 // We do not bother to filter these out, but clients should ignore them.
363 // These records serve as "filler" in three ways:
364 // - to skip large spans of unrelocated code (this is rare)
365 // - to pad out the relocInfo array to the required oop alignment
366 // - to disable old relocation information which is no longer applicable
367
368 inline friend relocInfo filler_relocInfo();
369
370 // Every non-prefix relocation may be preceded by at most one prefix,
371 // which supplies 1 or more halfwords of associated data. Conventionally,
372 // an int is represented by 0, 1, or 2 halfwords, depending on how
373 // many bits are required to represent the value. (In addition,
374 // if the sole halfword is a 10-bit unsigned number, it is made
375 // "immediate" in the prefix header word itself. This optimization
376 // is invisible outside this module.)
377
378 inline friend relocInfo prefix_relocInfo(int datalen);
379
380 protected:
381 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value
382 static relocInfo immediate_relocInfo(int data0) {
383 assert(fits_into_immediate(data0), "data0 in limits");
384 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0);
385 }
386 static bool fits_into_immediate(int data0) {
387 return (data0 >= 0 && data0 < datalen_limit);
388 }
389
390 public:
391 // Support routines for compilers.
392
393 // This routine takes an infant relocInfo (unprefixed) and
394 // edits in its prefix, if any. It also updates dest.locs_end.
395 void initialize(CodeSection* dest, Relocation* reloc);
396
397 // This routine updates a prefix and returns the limit pointer.
398 // It tries to compress the prefix from 32 to 16 bits, and if
399 // successful returns a reduced "prefix_limit" pointer.
400 relocInfo* finish_prefix(short* prefix_limit);
401
402 // bit-packers for the data array:
403
404 // As it happens, the bytes within the shorts are ordered natively,
405 // but the shorts within the word are ordered big-endian.
406 // This is an arbitrary choice, made this way mainly to ease debugging.
407 static int data0_from_int(jint x) { return x >> value_width; }
408 static int data1_from_int(jint x) { return (short)x; }
409 static jint jint_from_data(short* data) {
410 return (data[0] << value_width) + (unsigned short)data[1];
411 }
412
413 static jint short_data_at(int n, short* data, int datalen) {
414 return datalen > n ? data[n] : 0;
415 }
416
417 static jint jint_data_at(int n, short* data, int datalen) {
418 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen);
419 }
420
421 // Update methods for relocation information
422 // (since code is dynamically patched, we also need to dynamically update the relocation info)
423 // Both methods takes old_type, so it is able to performe sanity checks on the information removed.
424 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type);
425 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type);
426
427 // Machine dependent stuff
428 #include CPU_HEADER(relocInfo)
429
430 protected:
431 // Derived constant, based on format_width which is PD:
432 enum {
433 offset_width = nontype_width - format_width,
434 offset_mask = (1<<offset_width) - 1,
435 format_mask = (1<<format_width) - 1
436 };
437 public:
438 enum {
439 #ifdef _LP64
440 // for use in format
441 // format_width must be at least 1 on _LP64
442 narrow_oop_in_const = 1,
443 #endif
444 // Conservatively large estimate of maximum length (in shorts)
445 // of any relocation record.
446 // Extended format is length prefix, data words, and tag/offset suffix.
447 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1,
448 have_format = format_width > 0
449 };
450 };
451
452 #define FORWARD_DECLARE_EACH_CLASS(name) \
453 class name##_Relocation;
454 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS)
455 #undef FORWARD_DECLARE_EACH_CLASS
456
457
458
459 inline relocInfo filler_relocInfo() {
460 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit);
461 }
462
463 inline relocInfo prefix_relocInfo(int datalen = 0) {
464 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits");
465 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen);
466 }
467
468
469 // Holder for flyweight relocation objects.
470 // Although the flyweight subclasses are of varying sizes,
471 // the holder is "one size fits all".
472 class RelocationHolder VALUE_OBJ_CLASS_SPEC {
473 friend class Relocation;
474 friend class CodeSection;
475
476 private:
477 // this preallocated memory must accommodate all subclasses of Relocation
478 // (this number is assertion-checked in Relocation::operator new)
479 enum { _relocbuf_size = 5 };
480 void* _relocbuf[ _relocbuf_size ];
481
482 public:
483 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; }
484 inline relocInfo::relocType type() const;
485
486 // Add a constant offset to a relocation. Helper for class Address.
487 RelocationHolder plus(int offset) const;
488
489 inline RelocationHolder(); // initializes type to none
490
491 inline RelocationHolder(Relocation* r); // make a copy
492
493 static const RelocationHolder none;
494 };
495
496 // A RelocIterator iterates through the relocation information of a CodeBlob.
497 // It is a variable BoundRelocation which is able to take on successive
498 // values as it is advanced through a code stream.
499 // Usage:
500 // RelocIterator iter(nm);
501 // while (iter.next()) {
502 // iter.reloc()->some_operation();
503 // }
504 // or:
505 // RelocIterator iter(nm);
506 // while (iter.next()) {
507 // switch (iter.type()) {
508 // case relocInfo::oop_type :
509 // case relocInfo::ic_type :
510 // case relocInfo::prim_type :
511 // case relocInfo::uncommon_type :
512 // case relocInfo::runtime_call_type :
513 // case relocInfo::internal_word_type:
514 // case relocInfo::external_word_type:
515 // ...
516 // }
517 // }
518
519 class RelocIterator : public StackObj {
520 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor
521 friend class Relocation;
522 friend class relocInfo; // for change_reloc_info_for_address only
523 typedef relocInfo::relocType relocType;
524
525 private:
526 address _limit; // stop producing relocations after this _addr
527 relocInfo* _current; // the current relocation information
528 relocInfo* _end; // end marker; we're done iterating when _current == _end
529 CompiledMethod* _code; // compiled method containing _addr
530 address _addr; // instruction to which the relocation applies
531 short _databuf; // spare buffer for compressed data
532 short* _data; // pointer to the relocation's data
533 short _datalen; // number of halfwords in _data
534 char _format; // position within the instruction
535
536 // Base addresses needed to compute targets of section_word_type relocs.
537 address _section_start[SECT_LIMIT];
538 address _section_end [SECT_LIMIT];
539
540 void set_has_current(bool b) {
541 _datalen = !b ? -1 : 0;
542 debug_only(_data = NULL);
543 }
544 void set_current(relocInfo& ri) {
545 _current = &ri;
546 set_has_current(true);
547 }
548
549 RelocationHolder _rh; // where the current relocation is allocated
550
551 relocInfo* current() const { assert(has_current(), "must have current");
552 return _current; }
553
554 void set_limits(address begin, address limit);
555
556 void advance_over_prefix(); // helper method
557
558 void initialize_misc();
559
560 void initialize(CompiledMethod* nm, address begin, address limit);
561
562 RelocIterator() { initialize_misc(); }
563
564 public:
565 // constructor
566 RelocIterator(CompiledMethod* nm, address begin = NULL, address limit = NULL);
567 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL);
568
569 // get next reloc info, return !eos
570 bool next() {
571 _current++;
572 assert(_current <= _end, "must not overrun relocInfo");
573 if (_current == _end) {
574 set_has_current(false);
575 return false;
576 }
577 set_has_current(true);
578
579 if (_current->is_prefix()) {
580 advance_over_prefix();
581 assert(!current()->is_prefix(), "only one prefix at a time");
582 }
583
584 _addr += _current->addr_offset();
585
586 if (_limit != NULL && _addr >= _limit) {
587 set_has_current(false);
588 return false;
589 }
590
591 if (relocInfo::have_format) _format = current()->format();
592 return true;
593 }
594
595 // accessors
596 address limit() const { return _limit; }
597 void set_limit(address x);
598 relocType type() const { return current()->type(); }
599 int format() const { return (relocInfo::have_format) ? current()->format() : 0; }
600 address addr() const { return _addr; }
601 CompiledMethod* code() const { return _code; }
602 nmethod* code_as_nmethod() const;
603 short* data() const { return _data; }
604 int datalen() const { return _datalen; }
605 bool has_current() const { return _datalen >= 0; }
606
607 void set_addr(address addr) { _addr = addr; }
608 bool addr_in_const() const;
609
610 address section_start(int n) const {
611 assert(_section_start[n], "must be initialized");
612 return _section_start[n];
613 }
614 address section_end(int n) const {
615 assert(_section_end[n], "must be initialized");
616 return _section_end[n];
617 }
618
619 // The address points to the affected displacement part of the instruction.
620 // For RISC, this is just the whole instruction.
621 // For Intel, this is an unaligned 32-bit word.
622
623 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc.
624 #define EACH_TYPE(name) \
625 inline name##_Relocation* name##_reloc();
626 APPLY_TO_RELOCATIONS(EACH_TYPE)
627 #undef EACH_TYPE
628 // generic relocation accessor; switches on type to call the above
629 Relocation* reloc();
630
631 // CodeBlob's have relocation indexes for faster random access:
632 static int locs_and_index_size(int code_size, int locs_size);
633 // Store an index into [dest_start+dest_count..dest_end).
634 // At dest_start[0..dest_count] is the actual relocation information.
635 // Everything else up to dest_end is free space for the index.
636 static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end);
637
638 #ifndef PRODUCT
639 public:
640 void print();
641 void print_current();
642 #endif
643 };
644
645
646 // A Relocation is a flyweight object allocated within a RelocationHolder.
647 // It represents the relocation data of relocation record.
648 // So, the RelocIterator unpacks relocInfos into Relocations.
649
650 class Relocation VALUE_OBJ_CLASS_SPEC {
651 friend class RelocationHolder;
652 friend class RelocIterator;
653
654 private:
655 static void guarantee_size();
656
657 // When a relocation has been created by a RelocIterator,
658 // this field is non-null. It allows the relocation to know
659 // its context, such as the address to which it applies.
660 RelocIterator* _binding;
661
662 protected:
663 RelocIterator* binding() const {
664 assert(_binding != NULL, "must be bound");
665 return _binding;
666 }
667 void set_binding(RelocIterator* b) {
668 assert(_binding == NULL, "must be unbound");
669 _binding = b;
670 assert(_binding != NULL, "must now be bound");
671 }
672
673 Relocation() {
674 _binding = NULL;
675 }
676
677 static RelocationHolder newHolder() {
678 return RelocationHolder();
679 }
680
681 public:
682 void* operator new(size_t size, const RelocationHolder& holder) throw() {
683 if (size > sizeof(holder._relocbuf)) guarantee_size();
684 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree");
685 return holder.reloc();
686 }
687
688 // make a generic relocation for a given type (if possible)
689 static RelocationHolder spec_simple(relocInfo::relocType rtype);
690
691 // here is the type-specific hook which writes relocation data:
692 virtual void pack_data_to(CodeSection* dest) { }
693
694 // here is the type-specific hook which reads (unpacks) relocation data:
695 virtual void unpack_data() {
696 assert(datalen()==0 || type()==relocInfo::none, "no data here");
697 }
698
699 protected:
700 // Helper functions for pack_data_to() and unpack_data().
701
702 // Most of the compression logic is confined here.
703 // (The "immediate data" mechanism of relocInfo works independently
704 // of this stuff, and acts to further compress most 1-word data prefixes.)
705
706 // A variable-width int is encoded as a short if it will fit in 16 bits.
707 // The decoder looks at datalen to decide whether to unpack short or jint.
708 // Most relocation records are quite simple, containing at most two ints.
709
710 static bool is_short(jint x) { return x == (short)x; }
711 static short* add_short(short* p, int x) { *p++ = x; return p; }
712 static short* add_jint (short* p, jint x) {
713 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x);
714 return p;
715 }
716 static short* add_var_int(short* p, jint x) { // add a variable-width int
717 if (is_short(x)) p = add_short(p, x);
718 else p = add_jint (p, x);
719 return p;
720 }
721
722 static short* pack_1_int_to(short* p, jint x0) {
723 // Format is one of: [] [x] [Xx]
724 if (x0 != 0) p = add_var_int(p, x0);
725 return p;
726 }
727 int unpack_1_int() {
728 assert(datalen() <= 2, "too much data");
729 return relocInfo::jint_data_at(0, data(), datalen());
730 }
731
732 // With two ints, the short form is used only if both ints are short.
733 short* pack_2_ints_to(short* p, jint x0, jint x1) {
734 // Format is one of: [] [x y?] [Xx Y?y]
735 if (x0 == 0 && x1 == 0) {
736 // no halfwords needed to store zeroes
737 } else if (is_short(x0) && is_short(x1)) {
738 // 1-2 halfwords needed to store shorts
739 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1);
740 } else {
741 // 3-4 halfwords needed to store jints
742 p = add_jint(p, x0); p = add_var_int(p, x1);
743 }
744 return p;
745 }
746 void unpack_2_ints(jint& x0, jint& x1) {
747 int dlen = datalen();
748 short* dp = data();
749 if (dlen <= 2) {
750 x0 = relocInfo::short_data_at(0, dp, dlen);
751 x1 = relocInfo::short_data_at(1, dp, dlen);
752 } else {
753 assert(dlen <= 4, "too much data");
754 x0 = relocInfo::jint_data_at(0, dp, dlen);
755 x1 = relocInfo::jint_data_at(2, dp, dlen);
756 }
757 }
758
759 protected:
760 // platform-independent utility for patching constant section
761 void const_set_data_value (address x);
762 void const_verify_data_value (address x);
763 // platform-dependent utilities for decoding and patching instructions
764 void pd_set_data_value (address x, intptr_t off, bool verify_only = false); // a set or mem-ref
765 void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); }
766 address pd_call_destination (address orig_addr = NULL);
767 void pd_set_call_destination (address x);
768
769 // this extracts the address of an address in the code stream instead of the reloc data
770 address* pd_address_in_code ();
771
772 // this extracts an address from the code stream instead of the reloc data
773 address pd_get_address_from_code ();
774
775 // these convert from byte offsets, to scaled offsets, to addresses
776 static jint scaled_offset(address x, address base) {
777 int byte_offset = x - base;
778 int offset = -byte_offset / relocInfo::addr_unit();
779 assert(address_from_scaled_offset(offset, base) == x, "just checkin'");
780 return offset;
781 }
782 static jint scaled_offset_null_special(address x, address base) {
783 // Some relocations treat offset=0 as meaning NULL.
784 // Handle this extra convention carefully.
785 if (x == NULL) return 0;
786 assert(x != base, "offset must not be zero");
787 return scaled_offset(x, base);
788 }
789 static address address_from_scaled_offset(jint offset, address base) {
790 int byte_offset = -( offset * relocInfo::addr_unit() );
791 return base + byte_offset;
792 }
793
794 // helpers for mapping between old and new addresses after a move or resize
795 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest);
796 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest);
797 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false);
798
799 public:
800 // accessors which only make sense for a bound Relocation
801 address addr() const { return binding()->addr(); }
802 CompiledMethod* code() const { return binding()->code(); }
803 nmethod* code_as_nmethod() const { return binding()->code_as_nmethod(); }
804 bool addr_in_const() const { return binding()->addr_in_const(); }
805 protected:
806 short* data() const { return binding()->data(); }
807 int datalen() const { return binding()->datalen(); }
808 int format() const { return binding()->format(); }
809
810 public:
811 virtual relocInfo::relocType type() { return relocInfo::none; }
812
813 // is it a call instruction?
814 virtual bool is_call() { return false; }
815
816 // is it a data movement instruction?
817 virtual bool is_data() { return false; }
818
819 // some relocations can compute their own values
820 virtual address value();
821
822 // all relocations are able to reassert their values
823 virtual void set_value(address x);
824
825 virtual void clear_inline_cache() { }
826
827 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and
828 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is
829 // probably a reasonable assumption, since empty caches simplifies code reloacation.
830 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { }
831 };
832
833
834 // certain inlines must be deferred until class Relocation is defined:
835
836 inline RelocationHolder::RelocationHolder() {
837 // initialize the vtbl, just to keep things type-safe
838 new(*this) Relocation();
839 }
840
841
842 inline RelocationHolder::RelocationHolder(Relocation* r) {
843 // wordwise copy from r (ok if it copies garbage after r)
844 for (int i = 0; i < _relocbuf_size; i++) {
845 _relocbuf[i] = ((void**)r)[i];
846 }
847 }
848
849
850 relocInfo::relocType RelocationHolder::type() const {
851 return reloc()->type();
852 }
853
854 // A DataRelocation always points at a memory or load-constant instruction..
855 // It is absolute on most machines, and the constant is split on RISCs.
856 // The specific subtypes are oop, external_word, and internal_word.
857 // By convention, the "value" does not include a separately reckoned "offset".
858 class DataRelocation : public Relocation {
859 public:
860 bool is_data() { return true; }
861
862 // both target and offset must be computed somehow from relocation data
863 virtual int offset() { return 0; }
864 address value() = 0;
865 void set_value(address x) { set_value(x, offset()); }
866 void set_value(address x, intptr_t o) {
867 if (addr_in_const())
868 const_set_data_value(x);
869 else
870 pd_set_data_value(x, o);
871 }
872 void verify_value(address x) {
873 if (addr_in_const())
874 const_verify_data_value(x);
875 else
876 pd_verify_data_value(x, offset());
877 }
878
879 // The "o" (displacement) argument is relevant only to split relocations
880 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns
881 // can encode more than 32 bits between them. This allows compilers to
882 // share set-hi instructions between addresses that differ by a small
883 // offset (e.g., different static variables in the same class).
884 // On such machines, the "x" argument to set_value on all set-lo
885 // instructions must be the same as the "x" argument for the
886 // corresponding set-hi instructions. The "o" arguments for the
887 // set-hi instructions are ignored, and must not affect the high-half
888 // immediate constant. The "o" arguments for the set-lo instructions are
889 // added into the low-half immediate constant, and must not overflow it.
890 };
891
892 // A CallRelocation always points at a call instruction.
893 // It is PC-relative on most machines.
894 class CallRelocation : public Relocation {
895 public:
896 bool is_call() { return true; }
897
898 address destination() { return pd_call_destination(); }
899 void set_destination(address x); // pd_set_call_destination
900
901 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
902 address value() { return destination(); }
903 void set_value(address x) { set_destination(x); }
904 };
905
906 class oop_Relocation : public DataRelocation {
907 relocInfo::relocType type() { return relocInfo::oop_type; }
908
909 public:
910 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll]
911 // an oop in the CodeBlob's oop pool
912 static RelocationHolder spec(int oop_index, int offset = 0) {
913 assert(oop_index > 0, "must be a pool-resident oop");
914 RelocationHolder rh = newHolder();
915 new(rh) oop_Relocation(oop_index, offset);
916 return rh;
917 }
918 // an oop in the instruction stream
919 static RelocationHolder spec_for_immediate() {
920 const int oop_index = 0;
921 const int offset = 0; // if you want an offset, use the oop pool
922 RelocationHolder rh = newHolder();
923 new(rh) oop_Relocation(oop_index, offset);
924 return rh;
925 }
926
927 private:
928 jint _oop_index; // if > 0, index into CodeBlob::oop_at
929 jint _offset; // byte offset to apply to the oop itself
930
931 oop_Relocation(int oop_index, int offset) {
932 _oop_index = oop_index; _offset = offset;
933 }
934
935 friend class RelocIterator;
936 oop_Relocation() { }
937
938 public:
939 int oop_index() { return _oop_index; }
940 int offset() { return _offset; }
941
942 // data is packed in "2_ints" format: [i o] or [Ii Oo]
943 void pack_data_to(CodeSection* dest);
944 void unpack_data();
945
946 void fix_oop_relocation(); // reasserts oop value
947
948 void verify_oop_relocation();
949
950 address value() { return (address) *oop_addr(); }
951
952 bool oop_is_immediate() { return oop_index() == 0; }
953
954 oop* oop_addr(); // addr or &pool[jint_data]
955 oop oop_value(); // *oop_addr
956 // Note: oop_value transparently converts Universe::non_oop_word to NULL.
957 };
958
959
960 // copy of oop_Relocation for now but may delete stuff in both/either
961 class metadata_Relocation : public DataRelocation {
962 relocInfo::relocType type() { return relocInfo::metadata_type; }
963
964 public:
965 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll]
966 // an metadata in the CodeBlob's metadata pool
967 static RelocationHolder spec(int metadata_index, int offset = 0) {
968 assert(metadata_index > 0, "must be a pool-resident metadata");
969 RelocationHolder rh = newHolder();
970 new(rh) metadata_Relocation(metadata_index, offset);
971 return rh;
972 }
973 // an metadata in the instruction stream
974 static RelocationHolder spec_for_immediate() {
975 const int metadata_index = 0;
976 const int offset = 0; // if you want an offset, use the metadata pool
977 RelocationHolder rh = newHolder();
978 new(rh) metadata_Relocation(metadata_index, offset);
979 return rh;
980 }
981
982 private:
983 jint _metadata_index; // if > 0, index into nmethod::metadata_at
984 jint _offset; // byte offset to apply to the metadata itself
985
986 metadata_Relocation(int metadata_index, int offset) {
987 _metadata_index = metadata_index; _offset = offset;
988 }
989
990 friend class RelocIterator;
991 metadata_Relocation() { }
992
993 // Fixes a Metadata pointer in the code. Most platforms embeds the
994 // Metadata pointer in the code at compile time so this is empty
995 // for them.
996 void pd_fix_value(address x);
997
998 public:
999 int metadata_index() { return _metadata_index; }
1000 int offset() { return _offset; }
1001
1002 // data is packed in "2_ints" format: [i o] or [Ii Oo]
1003 void pack_data_to(CodeSection* dest);
1004 void unpack_data();
1005
1006 void fix_metadata_relocation(); // reasserts metadata value
1007
1008 void verify_metadata_relocation();
1009
1010 address value() { return (address) *metadata_addr(); }
1011
1012 bool metadata_is_immediate() { return metadata_index() == 0; }
1013
1014 Metadata** metadata_addr(); // addr or &pool[jint_data]
1015 Metadata* metadata_value(); // *metadata_addr
1016 // Note: metadata_value transparently converts Universe::non_metadata_word to NULL.
1017 };
1018
1019
1020 class virtual_call_Relocation : public CallRelocation {
1021 relocInfo::relocType type() { return relocInfo::virtual_call_type; }
1022
1023 public:
1024 // "cached_value" points to the first associated set-oop.
1025 // The oop_limit helps find the last associated set-oop.
1026 // (See comments at the top of this file.)
1027 static RelocationHolder spec(address cached_value, jint method_index = 0) {
1028 RelocationHolder rh = newHolder();
1029 new(rh) virtual_call_Relocation(cached_value, method_index);
1030 return rh;
1031 }
1032
1033 private:
1034 address _cached_value; // location of set-value instruction
1035 jint _method_index; // resolved method for a Java call
1036
1037 virtual_call_Relocation(address cached_value, int method_index) {
1038 _cached_value = cached_value;
1039 _method_index = method_index;
1040 assert(cached_value != NULL, "first oop address must be specified");
1041 }
1042
1043 friend class RelocIterator;
1044 virtual_call_Relocation() { }
1045
1046 public:
1047 address cached_value();
1048
1049 int method_index() { return _method_index; }
1050 Method* method_value();
1051
1052 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll]
1053 // oop_limit is set to 0 if the limit falls somewhere within the call.
1054 // When unpacking, a zero oop_limit is taken to refer to the end of the call.
1055 // (This has the effect of bringing in the call's delay slot on SPARC.)
1056 void pack_data_to(CodeSection* dest);
1057 void unpack_data();
1058
1059 void clear_inline_cache();
1060 };
1061
1062
1063 class opt_virtual_call_Relocation : public CallRelocation {
1064 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; }
1065
1066 public:
1067 static RelocationHolder spec(int method_index = 0) {
1068 RelocationHolder rh = newHolder();
1069 new(rh) opt_virtual_call_Relocation(method_index);
1070 return rh;
1071 }
1072
1073 private:
1074 jint _method_index; // resolved method for a Java call
1075
1076 opt_virtual_call_Relocation(int method_index) {
1077 _method_index = method_index;
1078 }
1079
1080 friend class RelocIterator;
1081 opt_virtual_call_Relocation() {}
1082
1083 public:
1084 int method_index() { return _method_index; }
1085 Method* method_value();
1086
1087 void pack_data_to(CodeSection* dest);
1088 void unpack_data();
1089
1090 void clear_inline_cache();
1091
1092 // find the matching static_stub
1093 address static_stub();
1094 };
1095
1096
1097 class static_call_Relocation : public CallRelocation {
1098 relocInfo::relocType type() { return relocInfo::static_call_type; }
1099
1100 public:
1101 static RelocationHolder spec(int method_index = 0) {
1102 RelocationHolder rh = newHolder();
1103 new(rh) static_call_Relocation(method_index);
1104 return rh;
1105 }
1106
1107 private:
1108 jint _method_index; // resolved method for a Java call
1109
1110 static_call_Relocation(int method_index) {
1111 _method_index = method_index;
1112 }
1113
1114 friend class RelocIterator;
1115 static_call_Relocation() {}
1116
1117 public:
1118 int method_index() { return _method_index; }
1119 Method* method_value();
1120
1121 void pack_data_to(CodeSection* dest);
1122 void unpack_data();
1123
1124 void clear_inline_cache();
1125
1126 // find the matching static_stub
1127 address static_stub();
1128 };
1129
1130 class static_stub_Relocation : public Relocation {
1131 relocInfo::relocType type() { return relocInfo::static_stub_type; }
1132
1133 public:
1134 static RelocationHolder spec(address static_call) {
1135 RelocationHolder rh = newHolder();
1136 new(rh) static_stub_Relocation(static_call);
1137 return rh;
1138 }
1139
1140 private:
1141 address _static_call; // location of corresponding static_call
1142
1143 static_stub_Relocation(address static_call) {
1144 _static_call = static_call;
1145 }
1146
1147 friend class RelocIterator;
1148 static_stub_Relocation() { }
1149
1150 public:
1151 void clear_inline_cache();
1152
1153 address static_call() { return _static_call; }
1154
1155 // data is packed as a scaled offset in "1_int" format: [c] or [Cc]
1156 void pack_data_to(CodeSection* dest);
1157 void unpack_data();
1158 };
1159
1160 class runtime_call_Relocation : public CallRelocation {
1161 relocInfo::relocType type() { return relocInfo::runtime_call_type; }
1162
1163 public:
1164 static RelocationHolder spec() {
1165 RelocationHolder rh = newHolder();
1166 new(rh) runtime_call_Relocation();
1167 return rh;
1168 }
1169
1170 private:
1171 friend class RelocIterator;
1172 runtime_call_Relocation() { }
1173
1174 public:
1175 };
1176
1177
1178 class runtime_call_w_cp_Relocation : public CallRelocation {
1179 relocInfo::relocType type() { return relocInfo::runtime_call_w_cp_type; }
1180
1181 public:
1182 static RelocationHolder spec() {
1183 RelocationHolder rh = newHolder();
1184 new(rh) runtime_call_w_cp_Relocation();
1185 return rh;
1186 }
1187
1188 private:
1189 friend class RelocIterator;
1190 runtime_call_w_cp_Relocation() { _offset = -4; /* <0 = invalid */ }
1191 // On z/Architecture, runtime calls are either a sequence
1192 // of two instructions (load destination of call from constant pool + do call)
1193 // or a pc-relative call. The pc-relative call is faster, but it can only
1194 // be used if the destination of the call is not too far away.
1195 // In order to be able to patch a pc-relative call back into one using
1196 // the constant pool, we have to remember the location of the call's destination
1197 // in the constant pool.
1198 int _offset;
1199
1200 public:
1201 void set_constant_pool_offset(int offset) { _offset = offset; }
1202 int get_constant_pool_offset() { return _offset; }
1203 void pack_data_to(CodeSection * dest);
1204 void unpack_data();
1205 };
1206
1207 // Trampoline Relocations.
1208 // A trampoline allows to encode a small branch in the code, even if there
1209 // is the chance that this branch can not reach all possible code locations.
1210 // If the relocation finds that a branch is too far for the instruction
1211 // in the code, it can patch it to jump to the trampoline where is
1212 // sufficient space for a far branch. Needed on PPC.
1213 class trampoline_stub_Relocation : public Relocation {
1214 relocInfo::relocType type() { return relocInfo::trampoline_stub_type; }
1215
1216 public:
1217 static RelocationHolder spec(address static_call) {
1218 RelocationHolder rh = newHolder();
1219 return (new (rh) trampoline_stub_Relocation(static_call));
1220 }
1221
1222 private:
1223 address _owner; // Address of the NativeCall that owns the trampoline.
1224
1225 trampoline_stub_Relocation(address owner) {
1226 _owner = owner;
1227 }
1228
1229 friend class RelocIterator;
1230 trampoline_stub_Relocation() { }
1231
1232 public:
1233
1234 // Return the address of the NativeCall that owns the trampoline.
1235 address owner() { return _owner; }
1236
1237 void pack_data_to(CodeSection * dest);
1238 void unpack_data();
1239
1240 // Find the trampoline stub for a call.
1241 static address get_trampoline_for(address call, nmethod* code);
1242 };
1243
1244 class external_word_Relocation : public DataRelocation {
1245 relocInfo::relocType type() { return relocInfo::external_word_type; }
1246
1247 public:
1248 static RelocationHolder spec(address target) {
1249 assert(target != NULL, "must not be null");
1250 RelocationHolder rh = newHolder();
1251 new(rh) external_word_Relocation(target);
1252 return rh;
1253 }
1254
1255 // Use this one where all 32/64 bits of the target live in the code stream.
1256 // The target must be an intptr_t, and must be absolute (not relative).
1257 static RelocationHolder spec_for_immediate() {
1258 RelocationHolder rh = newHolder();
1259 new(rh) external_word_Relocation(NULL);
1260 return rh;
1261 }
1262
1263 // Some address looking values aren't safe to treat as relocations
1264 // and should just be treated as constants.
1265 static bool can_be_relocated(address target) {
1266 assert(target == NULL || (uintptr_t)target >= (uintptr_t)os::vm_page_size(), INTPTR_FORMAT, (intptr_t)target);
1267 return target != NULL;
1268 }
1269
1270 private:
1271 address _target; // address in runtime
1272
1273 external_word_Relocation(address target) {
1274 _target = target;
1275 }
1276
1277 friend class RelocIterator;
1278 external_word_Relocation() { }
1279
1280 public:
1281 // data is packed as a well-known address in "1_int" format: [a] or [Aa]
1282 // The function runtime_address_to_index is used to turn full addresses
1283 // to short indexes, if they are pre-registered by the stub mechanism.
1284 // If the "a" value is 0 (i.e., _target is NULL), the address is stored
1285 // in the code stream. See external_word_Relocation::target().
1286 void pack_data_to(CodeSection* dest);
1287 void unpack_data();
1288
1289 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1290 address target(); // if _target==NULL, fetch addr from code stream
1291 address value() { return target(); }
1292 };
1293
1294 class internal_word_Relocation : public DataRelocation {
1295 relocInfo::relocType type() { return relocInfo::internal_word_type; }
1296
1297 public:
1298 static RelocationHolder spec(address target) {
1299 assert(target != NULL, "must not be null");
1300 RelocationHolder rh = newHolder();
1301 new(rh) internal_word_Relocation(target);
1302 return rh;
1303 }
1304
1305 // use this one where all the bits of the target can fit in the code stream:
1306 static RelocationHolder spec_for_immediate() {
1307 RelocationHolder rh = newHolder();
1308 new(rh) internal_word_Relocation(NULL);
1309 return rh;
1310 }
1311
1312 internal_word_Relocation(address target) {
1313 _target = target;
1314 _section = -1; // self-relative
1315 }
1316
1317 protected:
1318 address _target; // address in CodeBlob
1319 int _section; // section providing base address, if any
1320
1321 friend class RelocIterator;
1322 internal_word_Relocation() { }
1323
1324 // bit-width of LSB field in packed offset, if section >= 0
1325 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits
1326
1327 public:
1328 // data is packed as a scaled offset in "1_int" format: [o] or [Oo]
1329 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored
1330 // in the code stream. See internal_word_Relocation::target().
1331 // If _section is not -1, it is appended to the low bits of the offset.
1332 void pack_data_to(CodeSection* dest);
1333 void unpack_data();
1334
1335 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1336 address target(); // if _target==NULL, fetch addr from code stream
1337 int section() { return _section; }
1338 address value() { return target(); }
1339 };
1340
1341 class section_word_Relocation : public internal_word_Relocation {
1342 relocInfo::relocType type() { return relocInfo::section_word_type; }
1343
1344 public:
1345 static RelocationHolder spec(address target, int section) {
1346 RelocationHolder rh = newHolder();
1347 new(rh) section_word_Relocation(target, section);
1348 return rh;
1349 }
1350
1351 section_word_Relocation(address target, int section) {
1352 assert(target != NULL, "must not be null");
1353 assert(section >= 0, "must be a valid section");
1354 _target = target;
1355 _section = section;
1356 }
1357
1358 //void pack_data_to -- inherited
1359 void unpack_data();
1360
1361 private:
1362 friend class RelocIterator;
1363 section_word_Relocation() { }
1364 };
1365
1366
1367 class poll_Relocation : public Relocation {
1368 bool is_data() { return true; }
1369 relocInfo::relocType type() { return relocInfo::poll_type; }
1370 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest);
1371 };
1372
1373 class poll_return_Relocation : public poll_Relocation {
1374 relocInfo::relocType type() { return relocInfo::poll_return_type; }
1375 };
1376
1377 // We know all the xxx_Relocation classes, so now we can define these:
1378 #define EACH_CASE(name) \
1379 inline name##_Relocation* RelocIterator::name##_reloc() { \
1380 assert(type() == relocInfo::name##_type, "type must agree"); \
1381 /* The purpose of the placed "new" is to re-use the same */ \
1382 /* stack storage for each new iteration. */ \
1383 name##_Relocation* r = new(_rh) name##_Relocation(); \
1384 r->set_binding(this); \
1385 r->name##_Relocation::unpack_data(); \
1386 return r; \
1387 }
1388 APPLY_TO_RELOCATIONS(EACH_CASE);
1389 #undef EACH_CASE
1390
1391 inline RelocIterator::RelocIterator(CompiledMethod* nm, address begin, address limit) {
1392 initialize(nm, begin, limit);
1393 }
1394
1395 #endif // SHARE_VM_CODE_RELOCINFO_HPP