1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25 #ifndef SHARE_CODE_RELOCINFO_HPP
26 #define SHARE_CODE_RELOCINFO_HPP
27
28 #include "cppstdlib/new.hpp"
29 #include "memory/allocation.hpp"
30 #include "oops/oopsHierarchy.hpp"
31 #include "runtime/osInfo.hpp"
32 #include "utilities/checkedCast.hpp"
33 #include "utilities/globalDefinitions.hpp"
34 #include "utilities/macros.hpp"
35
36 class CodeBlob;
37 class Metadata;
38 class NativeMovConstReg;
39 class nmethod;
40
41 // Types in this file:
42 // relocInfo
43 // One element of an array of halfwords encoding compressed relocations.
44 // Also, the source of relocation types (relocInfo::oop_type, ...).
45 // Relocation
46 // A flyweight object representing a single relocation.
47 // It is fully unpacked from the compressed relocation array.
48 // metadata_Relocation, ... (subclasses of Relocation)
49 // The location of some type-specific operations (metadata_addr, ...).
50 // Also, the source of relocation specs (metadata_Relocation::spec, ...).
51 // oop_Relocation, ... (subclasses of Relocation)
52 // oops in the code stream (strings, class loaders)
53 // Also, the source of relocation specs (oop_Relocation::spec, ...).
54 // RelocationHolder
55 // A value type which acts as a union holding a Relocation object.
56 // Represents a relocation spec passed into a CodeBuffer during assembly.
57 // RelocIterator
58 // A StackObj which iterates over the relocations associated with
59 // a range of code addresses. Can be used to operate a copy of code.
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 interpretation 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] the index of an oop in the CodeBlob's oop pool
132 //
133 // relocInfo::internal_word_type -- an address within the same CodeBlob
134 // relocInfo::section_word_type -- same, but can refer to another section
135 // Value: an address in the CodeBlob's code or constants section
136 // Instruction types: memory (load), set (load address)
137 // Data: [] stored in 4 bytes of instruction
138 // [[L]l] a relative offset (see [About Offsets] below)
139 // In the case of section_word_type, the offset is relative to a section
140 // base address, and the section number (e.g., SECT_INSTS) is encoded
141 // into the low two bits of the offset L.
142 //
143 // relocInfo::external_word_type -- a fixed address in the runtime system
144 // Value: an address
145 // Instruction types: memory (load), set (load address)
146 // Data: [] stored in 4 bytes of instruction
147 // [n] the index of a "well-known" stub (usual case on RISC)
148 // [Ll] a 32-bit address
149 //
150 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system
151 // Value: an address
152 // Instruction types: PC-relative call (or a PC-relative branch)
153 // Data: [] stored in 4 bytes of instruction
154 //
155 // relocInfo::static_call_type -- a static call
156 // Value: an CodeBlob, a stub, or a fixup routine
157 // Instruction types: a call
158 // Data: []
159 // The identity of the callee is extracted from debugging information.
160 // //%note reloc_3
161 //
162 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline
163 // cache)
164 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine
165 // Instruction types: a call, plus some associated set-oop instructions
166 // Data: [] the associated set-oops are adjacent to the call
167 // [n] n is a relative offset to the first set-oop
168 // [[N]n l] and l is a limit within which the set-oops occur
169 // [Nn Ll] both n and l may be 32 bits if necessary
170 // The identity of the callee is extracted from debugging information.
171 //
172 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound
173 //
174 // Same info as a static_call_type. We use a special type, so the handling of
175 // virtuals and statics are separated.
176 //
177 //
178 // The offset n points to the first set-oop. (See [About Offsets] below.)
179 // In turn, the set-oop instruction specifies or contains an oop cell devoted
180 // exclusively to the IC call, which can be patched along with the call.
181 //
182 // The locations of any other set-oops are found by searching the relocation
183 // information starting at the first set-oop, and continuing until all
184 // relocations up through l have been inspected. The value l is another
185 // relative offset. (Both n and l are relative to the call's first byte.)
186 //
187 // The limit l of the search is exclusive. However, if it points within
188 // the call (e.g., offset zero), it is adjusted to point after the call.
189 //
190 // Since the offsets could be as wide as 32-bits, these conventions
191 // put no restrictions whatever upon code reorganization.
192 //
193 // The compiler is responsible for ensuring that transition from a clean
194 // state to a monomorphic compiled state is MP-safe. This implies that
195 // the system must respond well to intermediate states where a random
196 // subset of the set-oops has been correctly from the clean state
197 // upon entry to the VEP of the compiled method. In the case of a
198 // machine (Intel) with a single set-oop instruction, the 32-bit
199 // immediate field must not straddle a unit of memory coherence.
200 // //%note reloc_3
201 //
202 // relocInfo::static_stub_type -- an extra stub for each static_call_type
203 // Value: none
204 // Instruction types: a virtual call: { set_oop; jump; }
205 // Data: [[N]n] the offset of the associated static_call reloc
206 // This stub becomes the target of a static call which must be upgraded
207 // to a virtual call (because the callee is interpreted).
208 // See [About Offsets] below.
209 // //%note reloc_2
210 //
211 // relocInfo::poll_[return_]type -- a safepoint poll
212 // Value: none
213 // Instruction types: memory load or test
214 // Data: none
215 //
216 // For example:
217 //
218 // INSTRUCTIONS RELOC: TYPE PREFIX DATA
219 // ------------ ---- -----------
220 // sethi %hi(myObject), R oop_type [n(myObject)]
221 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset]
222 // add R2, 1, R2
223 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset]
224 //%note reloc_1
225 //
226 // This uses 4 instruction words, 8 relocation halfwords,
227 // and an entry (which is shareable) in the CodeBlob's oop pool,
228 // for a total of 36 bytes.
229 //
230 // Note that the compiler is responsible for ensuring the "fldOffset" when
231 // added to "%lo(myObject)" does not overflow the immediate fields of the
232 // memory instructions.
233 //
234 //
235 // [About Offsets] Relative offsets are supplied to this module as
236 // positive byte offsets, but they may be internally stored scaled
237 // and/or negated, depending on what is most compact for the target
238 // system. Since the object pointed to by the offset typically
239 // precedes the relocation address, it is profitable to store
240 // these negative offsets as positive numbers, but this decision
241 // is internal to the relocation information abstractions.
242 //
243
244 class Relocation;
245 class CodeBuffer;
246 class CodeSection;
247 class RelocIterator;
248
249 class relocInfo {
250 friend class RelocIterator;
251 public:
252 enum relocType {
253 none = 0, // Used when no relocation should be generated
254 oop_type = 1, // embedded oop
255 virtual_call_type = 2, // a standard inline cache call for a virtual send
256 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache)
257 static_call_type = 4, // a static send
258 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case)
259 runtime_call_type = 6, // call to fixed external routine
260 external_word_type = 7, // reference to fixed external address
261 internal_word_type = 8, // reference within the current code blob
262 section_word_type = 9, // internal, but a cross-section reference
263 poll_type = 10, // polling instruction for safepoints
264 poll_return_type = 11, // polling instruction for safepoints at return
265 metadata_type = 12, // metadata that used to be oops
266 trampoline_stub_type = 13, // stub-entry for trampoline
267 runtime_call_w_cp_type = 14, // Runtime call which may load its target from the constant pool
268 data_prefix_tag = 15, // tag for a prefix (carries data arguments)
269 post_call_nop_type = 16, // A tag for post call nop relocations
270 entry_guard_type = 17, // A tag for an nmethod entry barrier guard value
271 barrier_type = 18, // GC barrier data
272 patchable_barrier_type = 19, // Patchable GC barrier
273 type_mask = 31 // A mask which selects only the above values
274 };
275
276 private:
277 unsigned short _value;
278
279 static const enum class RawBitsToken {} RAW_BITS{};
280
281 relocInfo(relocType type, RawBitsToken, int bits)
282 : _value(checked_cast<unsigned short>((type << nontype_width) + bits)) { }
283
284 static relocType check_relocType(relocType type) NOT_DEBUG({ return type; });
285
286 static void check_offset_and_format(int offset, int format) NOT_DEBUG_RETURN;
287
288 static int compute_bits(int offset, int format) {
289 check_offset_and_format(offset, format);
290 return (offset / offset_unit) + (format << offset_width);
291 }
292
293 public:
294 relocInfo(relocType type, int offset, int format = 0)
295 : relocInfo(check_relocType(type), RAW_BITS, compute_bits(offset, format)) {}
296
297 #define APPLY_TO_RELOCATIONS(visitor) \
298 visitor(oop) \
299 visitor(metadata) \
300 visitor(virtual_call) \
301 visitor(opt_virtual_call) \
302 visitor(static_call) \
303 visitor(static_stub) \
304 visitor(runtime_call) \
305 visitor(runtime_call_w_cp) \
306 visitor(external_word) \
307 visitor(internal_word) \
308 visitor(poll) \
309 visitor(poll_return) \
310 visitor(section_word) \
311 visitor(trampoline_stub) \
312 visitor(post_call_nop) \
313 visitor(entry_guard) \
314 visitor(barrier) \
315 visitor(patchable_barrier) \
316
317
318 public:
319 enum : unsigned short{
320 value_width = sizeof(unsigned short) * BitsPerByte,
321 type_width = 5, // == log2(type_mask+1)
322 nontype_width = value_width - type_width,
323 datalen_width = nontype_width-1,
324 datalen_tag = 1 << datalen_width, // or-ed into _value
325 datalen_limit = 1 << datalen_width,
326 datalen_mask = (1 << datalen_width)-1
327 };
328
329 // accessors
330 public:
331 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); }
332 int format() const { return format_mask==0? 0: format_mask &
333 ((unsigned)_value >> offset_width); }
334 int addr_offset() const { assert(!is_prefix(), "must have offset");
335 return (_value & offset_mask)*offset_unit; }
336
337 protected:
338 const short* data() const { assert(is_datalen(), "must have data");
339 return (const short*)(this + 1); }
340 unsigned short datalen() const { assert(is_datalen(), "must have data");
341 return (_value & datalen_mask); }
342 unsigned short immediate() const { assert(is_immediate(), "must have immed");
343 return (_value & datalen_mask); }
344 public:
345 static int addr_unit() { return offset_unit; }
346 static int offset_limit() { return (1 << offset_width) * offset_unit; }
347
348 void set_type(relocType type);
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 static relocInfo filler_info() {
369 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit);
370 }
371
372 // Every non-prefix relocation may be preceded by at most one prefix,
373 // which supplies 1 or more halfwords of associated data. Conventionally,
374 // an int is represented by 0, 1, or 2 halfwords, depending on how
375 // many bits are required to represent the value. (In addition,
376 // if the sole halfword is a 10-bit unsigned number, it is made
377 // "immediate" in the prefix header word itself. This optimization
378 // is invisible outside this module.)
379
380 static relocInfo prefix_info(int datalen = 0) {
381 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits");
382 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen);
383 }
384
385 private:
386 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value
387 static relocInfo immediate_relocInfo(int data0) {
388 assert(fits_into_immediate(data0), "data0 in limits");
389 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0);
390 }
391 static bool fits_into_immediate(int data0) {
392 return (data0 >= 0 && data0 < datalen_limit);
393 }
394
395 public:
396 // Support routines for compilers.
397
398 // This routine takes an infant relocInfo (unprefixed) and
399 // edits in its prefix, if any. It also updates dest.locs_end.
400 void initialize(CodeSection* dest, Relocation* reloc);
401
402 // This routine updates a prefix and returns the limit pointer.
403 // It tries to compress the prefix from 32 to 16 bits, and if
404 // successful returns a reduced "prefix_limit" pointer.
405 relocInfo* finish_prefix(short* prefix_limit);
406
407 // bit-packers for the data array:
408
409 // As it happens, the bytes within the shorts are ordered natively,
410 // but the shorts within the word are ordered big-endian.
411 // This is an arbitrary choice, made this way mainly to ease debugging.
412 static short data0_from_int(jint x) { return (short)(x >> value_width); }
413 static short data1_from_int(jint x) { return (short)x; }
414 static jint jint_from_data(short* data) {
415 return (data[0] << value_width) + (unsigned short)data[1];
416 }
417
418 static jint short_data_at(int n, short* data, int datalen) {
419 return datalen > n ? data[n] : 0;
420 }
421
422 static jint jint_data_at(int n, short* data, int datalen) {
423 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen);
424 }
425
426 // Update methods for relocation information
427 // (since code is dynamically patched, we also need to dynamically update the relocation info)
428 // Both methods takes old_type, so it is able to perform sanity checks on the information removed.
429 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type);
430
431 // Machine dependent stuff
432 #include CPU_HEADER(relocInfo)
433
434 protected:
435 // Derived constant, based on format_width which is PD:
436 enum {
437 offset_width = nontype_width - format_width,
438 offset_mask = (1<<offset_width) - 1,
439 format_mask = (1<<format_width) - 1
440 };
441 public:
442 enum {
443 #ifdef _LP64
444 // for use in format
445 // format_width must be at least 1 on _LP64
446 narrow_oop_in_const = 1,
447 #endif
448 // Conservatively large estimate of maximum length (in shorts)
449 // of any relocation record.
450 // Extended format is length prefix, data words, and tag/offset suffix.
451 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1,
452 have_format = format_width > 0
453 };
454
455 static const char* type_name(relocInfo::relocType t);
456 };
457
458 #define FORWARD_DECLARE_EACH_CLASS(name) \
459 class name##_Relocation;
460 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS)
461 #undef FORWARD_DECLARE_EACH_CLASS
462
463 // Holder for flyweight relocation objects.
464 // Although the flyweight subclasses are of varying sizes,
465 // the holder is "one size fits all".
466 class RelocationHolder {
467 friend class Relocation;
468
469 private:
470 // A Relocation is "held" by placement constructing a Relocation into
471 // _relocbuf. Hence, _relocbuf must accomodate all subclasses of
472 // Relocation. We also need the Relocation base class to be at the same
473 // address as the start of the object, e.g. at the address of _relocbuf.
474 // Both of these requirements are checked (see emplace_relocation).
475 // The placement of the base class subobject isn't guaranteed by C++, since
476 // these aren't standard layout classes, but all supported implementations
477 // provide that behavior. If that changes, we can instead add a Relocation*
478 // _reloc member to capture the result of the placement new, and use that to
479 // access the base subobject.
480 static const size_t _relocbuf_size = 5 * sizeof(void*);
481 alignas(void*) char _relocbuf[_relocbuf_size];
482
483 template<typename Reloc, typename... Args>
484 void emplace_relocation(const Args&... args) {
485 static_assert(std::is_base_of<Relocation, Reloc>::value, "not Relocation");
486 static_assert(sizeof(Reloc) <= sizeof(_relocbuf), "_relocbuf too small");
487 Relocation* reloc = ::new (_relocbuf) Reloc(args...);
488 // Verify the base class subobject of the object constructed into
489 // _relocbuf is at the same address as the derived object.
490 assert(static_cast<const void*>(reloc) == _relocbuf, "invariant");
491 }
492
493 // Support for Relocation::copy_into.
494 // reloc should be a most derived object.
495 template<typename Reloc>
496 void copy_into_impl(const Reloc& reloc) {
497 emplace_relocation<Reloc>(reloc);
498 }
499
500 // Tag for selecting the constructor below and carrying the type of the
501 // relocation object the new holder will (initially) contain.
502 template<typename Reloc> struct Construct {};
503
504 // Constructor used by construct(). Constructs a new holder containing a
505 // relocation of type Reloc that is constructed using the provided args.
506 template<typename Reloc, typename... Args>
507 RelocationHolder(Construct<Reloc>, const Args&... args) {
508 emplace_relocation<Reloc>(args...);
509 }
510
511 public:
512 Relocation* reloc() const { return (Relocation*)_relocbuf; }
513 inline relocInfo::relocType type() const;
514
515 // Return a holder containing a relocation of type Reloc, constructed using args.
516 template<typename Reloc, typename... Args>
517 static RelocationHolder construct(const Args&... args) {
518 return RelocationHolder(Construct<Reloc>(), args...);
519 }
520
521 RelocationHolder(); // Initializes type to none.
522
523 // Depends on the destructor for all relocation types being trivial
524 // (verified in .cpp file).
525 ~RelocationHolder() = default;
526
527 RelocationHolder(const RelocationHolder& from);
528 RelocationHolder& operator=(const RelocationHolder& from);
529
530 static const RelocationHolder none;
531 };
532
533 // A RelocIterator iterates through the relocation information of a CodeBlob.
534 // It provides access to successive relocations as it is advanced through a
535 // code stream.
536 // Usage:
537 // RelocIterator iter(nm);
538 // while (iter.next()) {
539 // iter.reloc()->some_operation();
540 // }
541 // or:
542 // RelocIterator iter(nm);
543 // while (iter.next()) {
544 // switch (iter.type()) {
545 // case relocInfo::oop_type :
546 // case relocInfo::ic_type :
547 // case relocInfo::prim_type :
548 // case relocInfo::uncommon_type :
549 // case relocInfo::runtime_call_type :
550 // case relocInfo::internal_word_type:
551 // case relocInfo::external_word_type:
552 // ...
553 // }
554 // }
555
556 class RelocIterator : public StackObj {
557 friend class section_word_Relocation; // for section verification
558 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor
559 friend class Relocation;
560 friend class relocInfo; // for change_reloc_info_for_address only
561 typedef relocInfo::relocType relocType;
562
563 private:
564 address _limit; // stop producing relocations after this _addr
565 relocInfo* _current; // the current relocation information
566 relocInfo* _end; // end marker; we're done iterating when _current == _end
567 nmethod* _code; // compiled method containing _addr
568 address _addr; // instruction to which the relocation applies
569 short _databuf; // spare buffer for compressed data
570 short* _data; // pointer to the relocation's data
571 short _datalen; // number of halfwords in _data
572
573 // Base addresses needed to compute targets of section_word_type relocs.
574 address _section_start[SECT_LIMIT];
575 address _section_end [SECT_LIMIT];
576
577 void set_has_current(bool b) {
578 _datalen = !b ? -1 : 0;
579 DEBUG_ONLY(_data = nullptr);
580 }
581 void set_current(relocInfo& ri) {
582 _current = &ri;
583 set_has_current(true);
584 }
585
586 RelocationHolder _rh; // where the current relocation is allocated
587
588 relocInfo* current() const { assert(has_current(), "must have current");
589 return _current; }
590
591 void set_limits(address begin, address limit);
592
593 void advance_over_prefix(); // helper method
594
595 void initialize_misc();
596
597 void initialize(nmethod* nm, address begin, address limit);
598
599 RelocIterator() { initialize_misc(); }
600
601 public:
602 // constructor
603 RelocIterator(nmethod* nm, address begin = nullptr, address limit = nullptr);
604 RelocIterator(CodeSection* cb, address begin = nullptr, address limit = nullptr);
605 RelocIterator(CodeBlob* cb);
606
607 // get next reloc info, return !eos
608 bool next() {
609 _current++;
610 assert(_current <= _end, "must not overrun relocInfo");
611 if (_current == _end) {
612 set_has_current(false);
613 return false;
614 }
615 set_has_current(true);
616
617 if (_current->is_prefix()) {
618 advance_over_prefix();
619 assert(!current()->is_prefix(), "only one prefix at a time");
620 }
621
622 _addr += _current->addr_offset();
623
624 if (_limit != nullptr && _addr >= _limit) {
625 set_has_current(false);
626 return false;
627 }
628
629 return true;
630 }
631
632 // accessors
633 address limit() const { return _limit; }
634 relocType type() const { return current()->type(); }
635 int format() const { return (relocInfo::have_format) ? current()->format() : 0; }
636 address addr() const { return _addr; }
637 nmethod* code() const { return _code; }
638 short* data() const { return _data; }
639 int datalen() const { return _datalen; }
640 bool has_current() const { return _datalen >= 0; }
641 bool addr_in_const() const;
642
643 address section_start(int n) const {
644 assert(_section_start[n], "section %d must be initialized", n);
645 return _section_start[n];
646 }
647 address section_end(int n) const {
648 assert(_section_end[n], "section %d must be initialized", n);
649 return _section_end[n];
650 }
651
652 // The address points to the affected displacement part of the instruction.
653 // For RISC, this is just the whole instruction.
654 // For Intel, this is an unaligned 32-bit word.
655
656 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc.
657 #define EACH_TYPE(name) \
658 inline name##_Relocation* name##_reloc();
659 APPLY_TO_RELOCATIONS(EACH_TYPE)
660 #undef EACH_TYPE
661 // generic relocation accessor; switches on type to call the above
662 Relocation* reloc();
663
664 public:
665 void print_on(outputStream* st);
666 void print_current_on(outputStream* st);
667 };
668
669
670 // A Relocation is a flyweight object allocated within a RelocationHolder.
671 // It represents the relocation data of relocation record.
672 // So, the RelocIterator unpacks relocInfos into Relocations.
673
674 class Relocation {
675 friend class RelocIterator;
676 friend class AOTCodeReader;
677
678 private:
679 // When a relocation has been created by a RelocIterator,
680 // this field is non-null. It allows the relocation to know
681 // its context, such as the address to which it applies.
682 RelocIterator* _binding;
683
684 relocInfo::relocType _rtype;
685
686 protected:
687 RelocIterator* binding() const {
688 assert(_binding != nullptr, "must be bound");
689 return _binding;
690 }
691 void set_binding(RelocIterator* b) {
692 assert(_binding == nullptr, "must be unbound");
693 _binding = b;
694 assert(_binding != nullptr, "must now be bound");
695 }
696
697 explicit Relocation(relocInfo::relocType rtype) : _binding(nullptr), _rtype(rtype) { }
698
699 // Helper for copy_into functions for derived classes.
700 // Forwards operation to RelocationHolder::copy_into_impl so that
701 // RelocationHolder only needs to befriend this class, rather than all
702 // derived classes that implement copy_into.
703 template<typename Reloc>
704 static void copy_into_helper(const Reloc& reloc, RelocationHolder& holder) {
705 holder.copy_into_impl(reloc);
706 }
707
708 public:
709 // make a generic relocation for a given type (if possible)
710 static RelocationHolder spec_simple(relocInfo::relocType rtype);
711
712 // here is the type-specific hook which writes relocation data:
713 virtual void pack_data_to(CodeSection* dest) { }
714
715 // here is the type-specific hook which reads (unpacks) relocation data:
716 virtual void unpack_data() {
717 assert(datalen()==0 || type()==relocInfo::none, "no data here");
718 }
719
720 protected:
721 // Helper functions for pack_data_to() and unpack_data().
722
723 // Most of the compression logic is confined here.
724 // (The "immediate data" mechanism of relocInfo works independently
725 // of this stuff, and acts to further compress most 1-word data prefixes.)
726
727 // A variable-width int is encoded as a short if it will fit in 16 bits.
728 // The decoder looks at datalen to decide whether to unpack short or jint.
729 // Most relocation records are quite simple, containing at most two ints.
730
731 static bool is_short(jint x) { return x == (short)x; }
732 static short* add_short(short* p, short x) { *p++ = x; return p; }
733 static short* add_jint (short* p, jint x) {
734 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x);
735 return p;
736 }
737 static short* add_var_int(short* p, jint x) { // add a variable-width int
738 if (is_short(x)) p = add_short(p, (short)x);
739 else p = add_jint (p, x);
740 return p;
741 }
742
743 static short* pack_1_int_to(short* p, jint x0) {
744 // Format is one of: [] [x] [Xx]
745 if (x0 != 0) p = add_var_int(p, x0);
746 return p;
747 }
748 int unpack_1_int() {
749 assert(datalen() <= 2, "too much data");
750 return relocInfo::jint_data_at(0, data(), datalen());
751 }
752
753 // With two ints, the short form is used only if both ints are short.
754 short* pack_2_ints_to(short* p, jint x0, jint x1) {
755 // Format is one of: [] [x y?] [Xx Y?y]
756 if (x0 == 0 && x1 == 0) {
757 // no halfwords needed to store zeroes
758 } else if (is_short(x0) && is_short(x1)) {
759 // 1-2 halfwords needed to store shorts
760 p = add_short(p, (short)x0); if (x1!=0) p = add_short(p, (short)x1);
761 } else {
762 // 3-4 halfwords needed to store jints
763 p = add_jint(p, x0); p = add_var_int(p, x1);
764 }
765 return p;
766 }
767 void unpack_2_ints(jint& x0, jint& x1) {
768 int dlen = datalen();
769 short* dp = data();
770 if (dlen <= 2) {
771 x0 = relocInfo::short_data_at(0, dp, dlen);
772 x1 = relocInfo::short_data_at(1, dp, dlen);
773 } else {
774 assert(dlen <= 4, "too much data");
775 x0 = relocInfo::jint_data_at(0, dp, dlen);
776 x1 = relocInfo::jint_data_at(2, dp, dlen);
777 }
778 }
779
780 protected:
781 // platform-independent utility for patching constant section
782 void const_set_data_value (address x);
783 void const_verify_data_value (address x);
784 // platform-dependent utilities for decoding and patching instructions
785 void pd_set_data_value (address x, bool verify_only = false); // a set or mem-ref
786 void pd_verify_data_value (address x) { pd_set_data_value(x, true); }
787 address pd_call_destination (address orig_addr = nullptr);
788 void pd_set_call_destination (address x);
789
790 // this extracts the address of an address in the code stream instead of the reloc data
791 address* pd_address_in_code ();
792
793 // this extracts an address from the code stream instead of the reloc data
794 address pd_get_address_from_code ();
795
796 // these convert from byte offsets, to scaled offsets, to addresses
797 static jint scaled_offset(address x, address base) {
798 int byte_offset = checked_cast<int>(x - base);
799 int offset = -byte_offset / relocInfo::addr_unit();
800 assert(address_from_scaled_offset(offset, base) == x, "just checkin'");
801 return offset;
802 }
803 static jint scaled_offset_null_special(address x, address base) {
804 // Some relocations treat offset=0 as meaning nullptr.
805 // Handle this extra convention carefully.
806 if (x == nullptr) return 0;
807 assert(x != base, "offset must not be zero");
808 return scaled_offset(x, base);
809 }
810 static address address_from_scaled_offset(jint offset, address base) {
811 int byte_offset = -( offset * relocInfo::addr_unit() );
812 return base + byte_offset;
813 }
814
815 // helpers for mapping between old and new addresses after a move or resize
816 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest);
817 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest);
818 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false);
819
820 public:
821 // accessors which only make sense for a bound Relocation
822 address addr() const { return binding()->addr(); }
823 nmethod* code() const { return binding()->code(); }
824 bool addr_in_const() const { return binding()->addr_in_const(); }
825 protected:
826 short* data() const { return binding()->data(); }
827 int datalen() const { return binding()->datalen(); }
828
829 public:
830 // Make a filler relocation.
831 Relocation() : Relocation(relocInfo::none) {}
832
833 // Intentionally public non-virtual destructor, even though polymorphic. We
834 // never heap allocate a Relocation, so never delete through a base pointer.
835 // RelocationHolder depends on the destructor for all relocation types being
836 // trivial, so this must not be virtual (and hence non-trivial).
837 ~Relocation() = default;
838
839 int format() const { return binding()->format(); }
840
841 relocInfo::relocType type() const { return _rtype; }
842
843 // Copy this relocation into holder.
844 virtual void copy_into(RelocationHolder& holder) const;
845
846 // is it a call instruction?
847 virtual bool is_call() { return false; }
848
849 // is it a data movement instruction?
850 virtual bool is_data() { return false; }
851
852 // some relocations can compute their own values
853 virtual address value();
854
855 // all relocations are able to reassert their values
856 virtual void set_value(address x);
857
858 virtual void clear_inline_cache() {}
859
860 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and
861 // ic_call_type is not always position dependent (depending on the state of the cache)). However, this is
862 // probably a reasonable assumption, since empty caches simplifies code reloacation.
863 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { }
864 };
865
866
867 // certain inlines must be deferred until class Relocation is defined:
868
869 inline RelocationHolder::RelocationHolder() :
870 RelocationHolder(Construct<Relocation>())
871 {}
872
873 inline RelocationHolder::RelocationHolder(const RelocationHolder& from) {
874 from.reloc()->copy_into(*this);
875 }
876
877 inline RelocationHolder& RelocationHolder::operator=(const RelocationHolder& from) {
878 // All Relocation types are trivially destructible (verified in .cpp file),
879 // so we don't need to destruct our old value before copying over it.
880 // If not for that we would need to decide what to do about self-assignment.
881 from.reloc()->copy_into(*this);
882 return *this;
883 }
884
885 relocInfo::relocType RelocationHolder::type() const {
886 return reloc()->type();
887 }
888
889 // A DataRelocation always points at a memory or load-constant instruction..
890 // It is absolute on most machines, and the constant is split on RISCs.
891 // The specific subtypes are oop, external_word, and internal_word.
892 class DataRelocation : public Relocation {
893 public:
894 DataRelocation(relocInfo::relocType type) : Relocation(type) {}
895
896 bool is_data() override { return true; }
897
898 // target must be computed somehow from relocation data
899 address value() override = 0;
900 void set_value(address x) override {
901 if (addr_in_const()) {
902 const_set_data_value(x);
903 } else {
904 pd_set_data_value(x);
905 }
906 }
907 void verify_value(address x) {
908 if (addr_in_const()) {
909 const_verify_data_value(x);
910 } else {
911 pd_verify_data_value(x);
912 }
913 }
914 };
915
916 class post_call_nop_Relocation : public Relocation {
917 friend class RelocationHolder;
918
919 public:
920 post_call_nop_Relocation() : Relocation(relocInfo::post_call_nop_type) { }
921
922 static RelocationHolder spec() {
923 return RelocationHolder::construct<post_call_nop_Relocation>();
924 }
925
926 void copy_into(RelocationHolder& holder) const override;
927 };
928
929 class entry_guard_Relocation : public Relocation {
930 friend class RelocationHolder;
931
932 public:
933 entry_guard_Relocation() : Relocation(relocInfo::entry_guard_type) { }
934
935 static RelocationHolder spec() {
936 return RelocationHolder::construct<entry_guard_Relocation>();
937 }
938
939 void copy_into(RelocationHolder& holder) const override;
940 };
941
942 // A CallRelocation always points at a call instruction.
943 // It is PC-relative on most machines.
944 class CallRelocation : public Relocation {
945 public:
946 CallRelocation(relocInfo::relocType type) : Relocation(type) { }
947
948 bool is_call() override { return true; }
949
950 address destination() { return pd_call_destination(); }
951 void set_destination(address x); // pd_set_call_destination
952
953 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) override;
954 address value() override { return destination(); }
955 void set_value(address x) override { set_destination(x); }
956 };
957
958 class oop_Relocation : public DataRelocation {
959 public:
960 // an oop in the CodeBlob's oop pool; encoded as [n] or [Nn]
961 static RelocationHolder spec(int oop_index) {
962 assert(oop_index > 0, "must be a pool-resident oop");
963 return RelocationHolder::construct<oop_Relocation>(oop_index);
964 }
965 // an oop in the instruction stream; encoded as []
966 static RelocationHolder spec_for_immediate() {
967 // If no immediate oops are generated, we can skip some walks over nmethods.
968 // Assert that they don't get generated accidentally!
969 assert(relocInfo::mustIterateImmediateOopsInCode(),
970 "Must return true so we will search for oops as roots etc. in the code.");
971 const int oop_index = 0;
972 return RelocationHolder::construct<oop_Relocation>(oop_index);
973 }
974
975 void copy_into(RelocationHolder& holder) const override;
976
977 private:
978 jint _oop_index; // if > 0, index into CodeBlob::oop_at
979
980 oop_Relocation(int oop_index)
981 : DataRelocation(relocInfo::oop_type), _oop_index(oop_index) { }
982
983 friend class RelocationHolder;
984 oop_Relocation() : DataRelocation(relocInfo::oop_type) {}
985
986 public:
987 int oop_index() { return _oop_index; }
988
989 // oop_index is packed in "1_int" format: [n] or [Nn]
990 void pack_data_to(CodeSection* dest) override;
991 void unpack_data() override;
992
993 void fix_oop_relocation(); // reasserts oop value
994
995 void verify_oop_relocation();
996
997 address value() override { return *reinterpret_cast<address*>(oop_addr()); }
998
999 bool oop_is_immediate() { return oop_index() == 0; }
1000
1001 oop* oop_addr(); // addr or &pool[jint_data]
1002 oop oop_value(); // *oop_addr
1003 // Note: oop_value transparently converts Universe::non_oop_word to nullptr.
1004 };
1005
1006
1007 // copy of oop_Relocation for now but may delete stuff in both/either
1008 class metadata_Relocation : public DataRelocation {
1009
1010 public:
1011 // an metadata in the CodeBlob's metadata pool; encoded as [n] or [Nn]
1012 static RelocationHolder spec(int metadata_index) {
1013 assert(metadata_index > 0, "must be a pool-resident metadata");
1014 return RelocationHolder::construct<metadata_Relocation>(metadata_index);
1015 }
1016 // an metadata in the instruction stream; encoded as []
1017 static RelocationHolder spec_for_immediate() {
1018 const int metadata_index = 0;
1019 return RelocationHolder::construct<metadata_Relocation>(metadata_index);
1020 }
1021
1022 void copy_into(RelocationHolder& holder) const override;
1023
1024 private:
1025 jint _metadata_index; // if > 0, index into nmethod::metadata_at
1026
1027 metadata_Relocation(int metadata_index)
1028 : DataRelocation(relocInfo::metadata_type), _metadata_index(metadata_index) { }
1029
1030 friend class RelocationHolder;
1031 metadata_Relocation() : DataRelocation(relocInfo::metadata_type) { }
1032
1033 // Fixes a Metadata pointer in the code. Most platforms embeds the
1034 // Metadata pointer in the code at compile time so this is empty
1035 // for them.
1036 void pd_fix_value(address x);
1037
1038 public:
1039 int metadata_index() { return _metadata_index; }
1040
1041 // metadata_index is packed in "1_int" format: [n] or [Nn]
1042 void pack_data_to(CodeSection* dest) override;
1043 void unpack_data() override;
1044
1045 void fix_metadata_relocation(); // reasserts metadata value
1046
1047 address value() override { return (address) *metadata_addr(); }
1048
1049 bool metadata_is_immediate() { return metadata_index() == 0; }
1050
1051 Metadata** metadata_addr(); // addr or &pool[jint_data]
1052 Metadata* metadata_value(); // *metadata_addr
1053 // Note: metadata_value transparently converts Universe::non_metadata_word to nullptr.
1054 };
1055
1056
1057 class barrier_Relocation : public Relocation {
1058
1059 public:
1060 // The uninitialized value used before the relocation has been patched.
1061 // Code assumes that the unpatched value is zero.
1062 static const int16_t unpatched = 0;
1063
1064 static RelocationHolder spec() {
1065 return RelocationHolder::construct<barrier_Relocation>();
1066 }
1067
1068 void copy_into(RelocationHolder& holder) const override;
1069
1070 private:
1071 friend class RelocIterator;
1072 friend class RelocationHolder;
1073 barrier_Relocation() : Relocation(relocInfo::barrier_type) { }
1074 };
1075
1076 class patchable_barrier_Relocation : public Relocation {
1077 public:
1078 jint _metadata;
1079 jint _target_offset;
1080
1081 static RelocationHolder spec(int metadata) {
1082 return RelocationHolder::construct<patchable_barrier_Relocation>(metadata);
1083 }
1084
1085 patchable_barrier_Relocation(int metadata) : Relocation(relocInfo::patchable_barrier_type),
1086 _metadata(metadata), _target_offset(0) { }
1087
1088 void pack_data_to(CodeSection* dest) override;
1089 void unpack_data() override;
1090
1091 void copy_into(RelocationHolder& holder) const override;
1092
1093 jint metadata() const { return _metadata; }
1094 jint target_offset() const { return _target_offset; }
1095
1096 void set_target_offset(jint target_offset);
1097
1098 private:
1099 friend class RelocIterator;
1100 friend class RelocationHolder;
1101 patchable_barrier_Relocation() : Relocation(relocInfo::patchable_barrier_type) { }
1102 };
1103
1104 class virtual_call_Relocation : public CallRelocation {
1105
1106 public:
1107 // "cached_value" points to the first associated set-oop.
1108 // The oop_limit helps find the last associated set-oop.
1109 // (See comments at the top of this file.)
1110 static RelocationHolder spec(address cached_value, jint method_index = 0) {
1111 return RelocationHolder::construct<virtual_call_Relocation>(cached_value, method_index);
1112 }
1113
1114 void copy_into(RelocationHolder& holder) const override;
1115
1116 private:
1117 address _cached_value; // location of set-value instruction
1118 jint _method_index; // resolved method for a Java call
1119
1120 virtual_call_Relocation(address cached_value, int method_index)
1121 : CallRelocation(relocInfo::virtual_call_type),
1122 _cached_value(cached_value),
1123 _method_index(method_index) {
1124 assert(cached_value != nullptr, "first oop address must be specified");
1125 }
1126
1127 friend class RelocationHolder;
1128 virtual_call_Relocation() : CallRelocation(relocInfo::virtual_call_type) { }
1129
1130 public:
1131 address cached_value();
1132
1133 int method_index() { return _method_index; }
1134 Method* method_value();
1135
1136 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll]
1137 // oop_limit is set to 0 if the limit falls somewhere within the call.
1138 // When unpacking, a zero oop_limit is taken to refer to the end of the call.
1139 void pack_data_to(CodeSection* dest) override;
1140 void unpack_data() override;
1141
1142 void clear_inline_cache() override;
1143 };
1144
1145
1146 class opt_virtual_call_Relocation : public CallRelocation {
1147 public:
1148 static RelocationHolder spec(int method_index = 0) {
1149 return RelocationHolder::construct<opt_virtual_call_Relocation>(method_index);
1150 }
1151
1152 void copy_into(RelocationHolder& holder) const override;
1153
1154 private:
1155 jint _method_index; // resolved method for a Java call
1156
1157 opt_virtual_call_Relocation(int method_index)
1158 : CallRelocation(relocInfo::opt_virtual_call_type),
1159 _method_index(method_index) { }
1160
1161 friend class RelocationHolder;
1162 opt_virtual_call_Relocation() : CallRelocation(relocInfo::opt_virtual_call_type) {}
1163
1164 public:
1165 int method_index() { return _method_index; }
1166 Method* method_value();
1167
1168 void pack_data_to(CodeSection* dest) override;
1169 void unpack_data() override;
1170
1171 void clear_inline_cache() override;
1172
1173 // find the matching static_stub
1174 address static_stub();
1175 };
1176
1177
1178 class static_call_Relocation : public CallRelocation {
1179 public:
1180 static RelocationHolder spec(int method_index = 0) {
1181 return RelocationHolder::construct<static_call_Relocation>(method_index);
1182 }
1183
1184 void copy_into(RelocationHolder& holder) const override;
1185
1186 private:
1187 jint _method_index; // resolved method for a Java call
1188
1189 static_call_Relocation(int method_index)
1190 : CallRelocation(relocInfo::static_call_type),
1191 _method_index(method_index) { }
1192
1193 friend class RelocationHolder;
1194 static_call_Relocation() : CallRelocation(relocInfo::static_call_type) {}
1195
1196 public:
1197 int method_index() { return _method_index; }
1198 Method* method_value();
1199
1200 void pack_data_to(CodeSection* dest) override;
1201 void unpack_data() override;
1202
1203 void clear_inline_cache() override;
1204
1205 // find the matching static_stub
1206 address static_stub();
1207 };
1208
1209 class static_stub_Relocation : public Relocation {
1210 public:
1211 static RelocationHolder spec(address static_call) {
1212 return RelocationHolder::construct<static_stub_Relocation>(static_call);
1213 }
1214
1215 void copy_into(RelocationHolder& holder) const override;
1216
1217 private:
1218 address _static_call; // location of corresponding static_call
1219
1220 static_stub_Relocation(address static_call)
1221 : Relocation(relocInfo::static_stub_type),
1222 _static_call(static_call) { }
1223
1224 friend class RelocationHolder;
1225 static_stub_Relocation() : Relocation(relocInfo::static_stub_type) { }
1226
1227 public:
1228 void clear_inline_cache() override;
1229
1230 address static_call() { return _static_call; }
1231
1232 // data is packed as a scaled offset in "1_int" format: [c] or [Cc]
1233 void pack_data_to(CodeSection* dest) override;
1234 void unpack_data() override;
1235 };
1236
1237 class runtime_call_Relocation : public CallRelocation {
1238
1239 public:
1240 static RelocationHolder spec() {
1241 return RelocationHolder::construct<runtime_call_Relocation>();
1242 }
1243
1244 void copy_into(RelocationHolder& holder) const override;
1245
1246 private:
1247 friend class RelocationHolder;
1248 runtime_call_Relocation() : CallRelocation(relocInfo::runtime_call_type) { }
1249 };
1250
1251
1252 class runtime_call_w_cp_Relocation : public CallRelocation {
1253 public:
1254 static RelocationHolder spec() {
1255 return RelocationHolder::construct<runtime_call_w_cp_Relocation>();
1256 }
1257
1258 void copy_into(RelocationHolder& holder) const override;
1259
1260 private:
1261 friend class RelocationHolder;
1262 runtime_call_w_cp_Relocation()
1263 : CallRelocation(relocInfo::runtime_call_w_cp_type),
1264 _offset(-4) /* <0 = invalid */ { }
1265
1266 // On z/Architecture, runtime calls are either a sequence
1267 // of two instructions (load destination of call from constant pool + do call)
1268 // or a pc-relative call. The pc-relative call is faster, but it can only
1269 // be used if the destination of the call is not too far away.
1270 // In order to be able to patch a pc-relative call back into one using
1271 // the constant pool, we have to remember the location of the call's destination
1272 // in the constant pool.
1273 int _offset;
1274
1275 public:
1276 void set_constant_pool_offset(int offset) { _offset = offset; }
1277 int get_constant_pool_offset() { return _offset; }
1278 void pack_data_to(CodeSection * dest) override;
1279 void unpack_data() override;
1280 };
1281
1282 // Trampoline Relocations.
1283 // A trampoline allows to encode a small branch in the code, even if there
1284 // is the chance that this branch can not reach all possible code locations.
1285 // If the relocation finds that a branch is too far for the instruction
1286 // in the code, it can patch it to jump to the trampoline where is
1287 // sufficient space for a far branch. Needed on PPC.
1288 class trampoline_stub_Relocation : public Relocation {
1289 #ifdef USE_TRAMPOLINE_STUB_FIX_OWNER
1290 void pd_fix_owner_after_move();
1291 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) override;
1292 #endif
1293
1294 public:
1295 static RelocationHolder spec(address static_call) {
1296 return RelocationHolder::construct<trampoline_stub_Relocation>(static_call);
1297 }
1298
1299 void copy_into(RelocationHolder& holder) const override;
1300
1301 private:
1302 address _owner; // Address of the NativeCall that owns the trampoline.
1303
1304 trampoline_stub_Relocation(address owner)
1305 : Relocation(relocInfo::trampoline_stub_type),
1306 _owner(owner) { }
1307
1308 friend class RelocationHolder;
1309 trampoline_stub_Relocation() : Relocation(relocInfo::trampoline_stub_type) { }
1310
1311 public:
1312
1313 // Return the address of the NativeCall that owns the trampoline.
1314 address owner() { return _owner; }
1315
1316 void pack_data_to(CodeSection * dest) override;
1317 void unpack_data() override;
1318
1319 // Find the trampoline stub for a call.
1320 static address get_trampoline_for(address call, nmethod* code);
1321 };
1322
1323 class external_word_Relocation : public DataRelocation {
1324 public:
1325 static RelocationHolder spec(address target) {
1326 assert(target != nullptr, "must not be null");
1327 return RelocationHolder::construct<external_word_Relocation>(target);
1328 }
1329
1330 // Use this one where all 32/64 bits of the target live in the code stream.
1331 // The target must be an intptr_t, and must be absolute (not relative).
1332 static RelocationHolder spec_for_immediate() {
1333 return RelocationHolder::construct<external_word_Relocation>(nullptr);
1334 }
1335
1336 void copy_into(RelocationHolder& holder) const override;
1337
1338 // Some address looking values aren't safe to treat as relocations
1339 // and should just be treated as constants.
1340 static bool can_be_relocated(address target) {
1341 assert(target == nullptr || (uintptr_t)target >= (uintptr_t)OSInfo::vm_page_size(), INTPTR_FORMAT, (intptr_t)target);
1342 return target != nullptr;
1343 }
1344
1345 private:
1346 address _target; // address in runtime
1347
1348 external_word_Relocation(address target)
1349 : DataRelocation(relocInfo::external_word_type), _target(target) { }
1350
1351 friend class RelocationHolder;
1352 external_word_Relocation() : DataRelocation(relocInfo::external_word_type) { }
1353
1354 public:
1355 // data is packed as a well-known address in "1_int" format: [a] or [Aa]
1356 // The function runtime_address_to_index is used to turn full addresses
1357 // to short indexes, if they are pre-registered by the stub mechanism.
1358 // If the "a" value is 0 (i.e., _target is nullptr), the address is stored
1359 // in the code stream. See external_word_Relocation::target().
1360 void pack_data_to(CodeSection* dest) override;
1361 void unpack_data() override;
1362
1363 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) override;
1364 address target(); // if _target==nullptr, fetch addr from code stream
1365 address value() override { return target(); }
1366 };
1367
1368 class internal_word_Relocation : public DataRelocation {
1369
1370 public:
1371 static RelocationHolder spec(address target) {
1372 assert(target != nullptr, "must not be null");
1373 return RelocationHolder::construct<internal_word_Relocation>(target);
1374 }
1375
1376 // use this one where all the bits of the target can fit in the code stream:
1377 static RelocationHolder spec_for_immediate() {
1378 return RelocationHolder::construct<internal_word_Relocation>(nullptr);
1379 }
1380
1381 void copy_into(RelocationHolder& holder) const override;
1382
1383 // default section -1 means self-relative
1384 internal_word_Relocation(address target, int section = -1,
1385 relocInfo::relocType type = relocInfo::internal_word_type)
1386 : DataRelocation(type), _target(target), _section(section) { }
1387
1388 protected:
1389 address _target; // address in CodeBlob
1390 int _section; // section providing base address, if any
1391
1392 friend class RelocationHolder;
1393 internal_word_Relocation(relocInfo::relocType type = relocInfo::internal_word_type)
1394 : DataRelocation(type) { }
1395
1396 // bit-width of LSB field in packed offset, if section >= 0
1397 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits
1398
1399 public:
1400 // data is packed as a scaled offset in "1_int" format: [o] or [Oo]
1401 // If the "o" value is 0 (i.e., _target is nullptr), the offset is stored
1402 // in the code stream. See internal_word_Relocation::target().
1403 // If _section is not -1, it is appended to the low bits of the offset.
1404 void pack_data_to(CodeSection* dest) override;
1405 void unpack_data() override;
1406
1407 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) override;
1408 void fix_relocation_after_aot_load(address orig_base_addr, address current_base_addr);
1409
1410 address target(); // if _target==nullptr, fetch addr from code stream
1411 int section() { return _section; }
1412 address value() override { return target(); }
1413 };
1414
1415 class section_word_Relocation : public internal_word_Relocation {
1416 public:
1417 static RelocationHolder spec(address target, int section) {
1418 return RelocationHolder::construct<section_word_Relocation>(target, section);
1419 }
1420
1421 void copy_into(RelocationHolder& holder) const override;
1422
1423 section_word_Relocation(address target, int section)
1424 : internal_word_Relocation(target, section, relocInfo::section_word_type) {
1425 assert(target != nullptr, "must not be null");
1426 assert(section >= 0 && section < RelocIterator::SECT_LIMIT, "must be a valid section");
1427 }
1428
1429 //void pack_data_to -- inherited
1430 void unpack_data() override;
1431
1432 private:
1433 friend class RelocationHolder;
1434 section_word_Relocation() : internal_word_Relocation(relocInfo::section_word_type) { }
1435 };
1436
1437
1438 class poll_Relocation : public Relocation {
1439 bool is_data() override { return true; }
1440 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) override;
1441 public:
1442 poll_Relocation(relocInfo::relocType type = relocInfo::poll_type) : Relocation(type) { }
1443
1444 void copy_into(RelocationHolder& holder) const override;
1445 };
1446
1447 class poll_return_Relocation : public poll_Relocation {
1448 public:
1449 poll_return_Relocation() : poll_Relocation(relocInfo::relocInfo::poll_return_type) { }
1450
1451 void copy_into(RelocationHolder& holder) const override;
1452 };
1453
1454 // We know all the xxx_Relocation classes, so now we can define these:
1455 #define EACH_CASE_AUX(Accessor, Reloc) \
1456 inline Reloc* RelocIterator::Accessor() { \
1457 static const RelocationHolder proto = RelocationHolder::construct<Reloc>(); \
1458 assert(type() == proto.type(), "type must agree"); \
1459 _rh = proto; \
1460 Reloc* r = static_cast<Reloc*>(_rh.reloc()); \
1461 r->set_binding(this); \
1462 r->Reloc::unpack_data(); \
1463 return r; \
1464 }
1465 #define EACH_CASE(name) \
1466 EACH_CASE_AUX(PASTE_TOKENS(name, _reloc), PASTE_TOKENS(name, _Relocation))
1467 APPLY_TO_RELOCATIONS(EACH_CASE);
1468 #undef EACH_CASE_AUX
1469 #undef EACH_CASE
1470
1471 inline RelocIterator::RelocIterator(nmethod* nm, address begin, address limit) {
1472 initialize(nm, begin, limit);
1473 }
1474
1475 #endif // SHARE_CODE_RELOCINFO_HPP