1 /* 2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_CODE_RELOCINFO_HPP 26 #define SHARE_VM_CODE_RELOCINFO_HPP 27 28 #include "runtime/os.hpp" 29 #include "utilities/macros.hpp" 30 31 class nmethod; 32 class CompiledMethod; 33 class Metadata; 34 class NativeMovConstReg; 35 36 // Types in this file: 37 // relocInfo 38 // One element of an array of halfwords encoding compressed relocations. 39 // Also, the source of relocation types (relocInfo::oop_type, ...). 40 // Relocation 41 // A flyweight object representing a single relocation. 42 // It is fully unpacked from the compressed relocation array. 43 // metadata_Relocation, ... (subclasses of Relocation) 44 // The location of some type-specific operations (metadata_addr, ...). 45 // Also, the source of relocation specs (metadata_Relocation::spec, ...). 46 // oop_Relocation, ... (subclasses of Relocation) 47 // oops in the code stream (strings, class loaders) 48 // Also, the source of relocation specs (oop_Relocation::spec, ...). 49 // RelocationHolder 50 // A value type which acts as a union holding a Relocation object. 51 // Represents a relocation spec passed into a CodeBuffer during assembly. 52 // RelocIterator 53 // A StackObj which iterates over the relocations associated with 54 // a range of code addresses. Can be used to operate a copy of code. 55 // BoundRelocation 56 // An _internal_ type shared by packers and unpackers of relocations. 57 // It pastes together a RelocationHolder with some pointers into 58 // code and relocInfo streams. 59 60 61 // Notes on relocType: 62 // 63 // These hold enough information to read or write a value embedded in 64 // the instructions of an CodeBlob. They're used to update: 65 // 66 // 1) embedded oops (isOop() == true) 67 // 2) inline caches (isIC() == true) 68 // 3) runtime calls (isRuntimeCall() == true) 69 // 4) internal word ref (isInternalWord() == true) 70 // 5) external word ref (isExternalWord() == true) 71 // 72 // when objects move (GC) or if code moves (compacting the code heap). 73 // They are also used to patch the code (if a call site must change) 74 // 75 // A relocInfo is represented in 16 bits: 76 // 4 bits indicating the relocation type 77 // 12 bits indicating the offset from the previous relocInfo address 78 // 79 // The offsets accumulate along the relocInfo stream to encode the 80 // address within the CodeBlob, which is named RelocIterator::addr(). 81 // The address of a particular relocInfo always points to the first 82 // byte of the relevant instruction (and not to any of its subfields 83 // or embedded immediate constants). 84 // 85 // The offset value is scaled appropriately for the target machine. 86 // (See relocInfo_<arch>.hpp for the offset scaling.) 87 // 88 // On some machines, there may also be a "format" field which may provide 89 // additional information about the format of the instruction stream 90 // at the corresponding code address. The format value is usually zero. 91 // Any machine (such as Intel) whose instructions can sometimes contain 92 // more than one relocatable constant needs format codes to distinguish 93 // which operand goes with a given relocation. 94 // 95 // If the target machine needs N format bits, the offset has 12-N bits, 96 // the format is encoded between the offset and the type, and the 97 // relocInfo_<arch>.hpp file has manifest constants for the format codes. 98 // 99 // If the type is "data_prefix_tag" then the offset bits are further encoded, 100 // and in fact represent not a code-stream offset but some inline data. 101 // The data takes the form of a counted sequence of halfwords, which 102 // precedes the actual relocation record. (Clients never see it directly.) 103 // The interpetation of this extra data depends on the relocation type. 104 // 105 // On machines that have 32-bit immediate fields, there is usually 106 // little need for relocation "prefix" data, because the instruction stream 107 // is a perfectly reasonable place to store the value. On machines in 108 // which 32-bit values must be "split" across instructions, the relocation 109 // data is the "true" specification of the value, which is then applied 110 // to some field of the instruction (22 or 13 bits, on SPARC). 111 // 112 // Whenever the location of the CodeBlob changes, any PC-relative 113 // relocations, and any internal_word_type relocations, must be reapplied. 114 // After the GC runs, oop_type relocations must be reapplied. 115 // 116 // 117 // Here are meanings of the types: 118 // 119 // relocInfo::none -- a filler record 120 // Value: none 121 // Instruction: The corresponding code address is ignored 122 // Data: Any data prefix and format code are ignored 123 // (This means that any relocInfo can be disabled by setting 124 // its type to none. See relocInfo::remove.) 125 // 126 // relocInfo::oop_type, relocInfo::metadata_type -- a reference to an oop or meta data 127 // Value: an oop, or else the address (handle) of an oop 128 // Instruction types: memory (load), set (load address) 129 // Data: [] an oop stored in 4 bytes of instruction 130 // [n] n is the index of an oop in the CodeBlob's oop pool 131 // [[N]n l] and l is a byte offset to be applied to the oop 132 // [Nn Ll] both index and offset may be 32 bits if necessary 133 // Here is a special hack, used only by the old compiler: 134 // [[N]n 00] the value is the __address__ of the nth oop in the pool 135 // (Note that the offset allows optimal references to class variables.) 136 // 137 // relocInfo::internal_word_type -- an address within the same CodeBlob 138 // relocInfo::section_word_type -- same, but can refer to another section 139 // Value: an address in the CodeBlob's code or constants section 140 // Instruction types: memory (load), set (load address) 141 // Data: [] stored in 4 bytes of instruction 142 // [[L]l] a relative offset (see [About Offsets] below) 143 // In the case of section_word_type, the offset is relative to a section 144 // base address, and the section number (e.g., SECT_INSTS) is encoded 145 // into the low two bits of the offset L. 146 // 147 // relocInfo::external_word_type -- a fixed address in the runtime system 148 // Value: an address 149 // Instruction types: memory (load), set (load address) 150 // Data: [] stored in 4 bytes of instruction 151 // [n] the index of a "well-known" stub (usual case on RISC) 152 // [Ll] a 32-bit address 153 // 154 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system 155 // Value: an address 156 // Instruction types: PC-relative call (or a PC-relative branch) 157 // Data: [] stored in 4 bytes of instruction 158 // 159 // relocInfo::static_call_type -- a static call 160 // Value: an CodeBlob, a stub, or a fixup routine 161 // Instruction types: a call 162 // Data: [] 163 // The identity of the callee is extracted from debugging information. 164 // //%note reloc_3 165 // 166 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline 167 // cache) 168 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine 169 // Instruction types: a call, plus some associated set-oop instructions 170 // Data: [] the associated set-oops are adjacent to the call 171 // [n] n is a relative offset to the first set-oop 172 // [[N]n l] and l is a limit within which the set-oops occur 173 // [Nn Ll] both n and l may be 32 bits if necessary 174 // The identity of the callee is extracted from debugging information. 175 // 176 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound 177 // 178 // Same info as a static_call_type. We use a special type, so the handling of 179 // virtuals and statics are separated. 180 // 181 // 182 // The offset n points to the first set-oop. (See [About Offsets] below.) 183 // In turn, the set-oop instruction specifies or contains an oop cell devoted 184 // exclusively to the IC call, which can be patched along with the call. 185 // 186 // The locations of any other set-oops are found by searching the relocation 187 // information starting at the first set-oop, and continuing until all 188 // relocations up through l have been inspected. The value l is another 189 // relative offset. (Both n and l are relative to the call's first byte.) 190 // 191 // The limit l of the search is exclusive. However, if it points within 192 // the call (e.g., offset zero), it is adjusted to point after the call and 193 // any associated machine-specific delay slot. 194 // 195 // Since the offsets could be as wide as 32-bits, these conventions 196 // put no restrictions whatever upon code reorganization. 197 // 198 // The compiler is responsible for ensuring that transition from a clean 199 // state to a monomorphic compiled state is MP-safe. This implies that 200 // the system must respond well to intermediate states where a random 201 // subset of the set-oops has been correctly from the clean state 202 // upon entry to the VEP of the compiled method. In the case of a 203 // machine (Intel) with a single set-oop instruction, the 32-bit 204 // immediate field must not straddle a unit of memory coherence. 205 // //%note reloc_3 206 // 207 // relocInfo::static_stub_type -- an extra stub for each static_call_type 208 // Value: none 209 // Instruction types: a virtual call: { set_oop; jump; } 210 // Data: [[N]n] the offset of the associated static_call reloc 211 // This stub becomes the target of a static call which must be upgraded 212 // to a virtual call (because the callee is interpreted). 213 // See [About Offsets] below. 214 // //%note reloc_2 215 // 216 // relocInfo::poll_[return_]type -- a safepoint poll 217 // Value: none 218 // Instruction types: memory load or test 219 // Data: none 220 // 221 // For example: 222 // 223 // INSTRUCTIONS RELOC: TYPE PREFIX DATA 224 // ------------ ---- ----------- 225 // sethi %hi(myObject), R oop_type [n(myObject)] 226 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset] 227 // add R2, 1, R2 228 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset] 229 //%note reloc_1 230 // 231 // This uses 4 instruction words, 8 relocation halfwords, 232 // and an entry (which is sharable) in the CodeBlob's oop pool, 233 // for a total of 36 bytes. 234 // 235 // Note that the compiler is responsible for ensuring the "fldOffset" when 236 // added to "%lo(myObject)" does not overflow the immediate fields of the 237 // memory instructions. 238 // 239 // 240 // [About Offsets] Relative offsets are supplied to this module as 241 // positive byte offsets, but they may be internally stored scaled 242 // and/or negated, depending on what is most compact for the target 243 // system. Since the object pointed to by the offset typically 244 // precedes the relocation address, it is profitable to store 245 // these negative offsets as positive numbers, but this decision 246 // is internal to the relocation information abstractions. 247 // 248 249 class Relocation; 250 class CodeBuffer; 251 class CodeSection; 252 class RelocIterator; 253 254 class relocInfo { 255 friend class RelocIterator; 256 public: 257 enum relocType { 258 none = 0, // Used when no relocation should be generated 259 oop_type = 1, // embedded oop 260 virtual_call_type = 2, // a standard inline cache call for a virtual send 261 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache) 262 static_call_type = 4, // a static send 263 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case) 264 runtime_call_type = 6, // call to fixed external routine 265 external_word_type = 7, // reference to fixed external address 266 internal_word_type = 8, // reference within the current code blob 267 section_word_type = 9, // internal, but a cross-section reference 268 poll_type = 10, // polling instruction for safepoints 269 poll_return_type = 11, // polling instruction for safepoints at return 270 metadata_type = 12, // metadata that used to be oops 271 trampoline_stub_type = 13, // stub-entry for trampoline 272 runtime_call_w_cp_type = 14, // Runtime call which may load its target from the constant pool 273 data_prefix_tag = 15, // tag for a prefix (carries data arguments) 274 type_mask = 15 // A mask which selects only the above values 275 }; 276 277 protected: 278 unsigned short _value; 279 280 enum RawBitsToken { RAW_BITS }; 281 relocInfo(relocType type, RawBitsToken ignore, int bits) 282 : _value((type << nontype_width) + bits) { } 283 284 relocInfo(relocType type, RawBitsToken ignore, int off, int f) 285 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { } 286 287 public: 288 // constructor 289 relocInfo(relocType type, int offset, int format = 0) 290 #ifndef ASSERT 291 { 292 (*this) = relocInfo(type, RAW_BITS, offset, format); 293 } 294 #else 295 // Put a bunch of assertions out-of-line. 296 ; 297 #endif 298 299 #define APPLY_TO_RELOCATIONS(visitor) \ 300 visitor(oop) \ 301 visitor(metadata) \ 302 visitor(virtual_call) \ 303 visitor(opt_virtual_call) \ 304 visitor(static_call) \ 305 visitor(static_stub) \ 306 visitor(runtime_call) \ 307 visitor(runtime_call_w_cp) \ 308 visitor(external_word) \ 309 visitor(internal_word) \ 310 visitor(poll) \ 311 visitor(poll_return) \ 312 visitor(section_word) \ 313 visitor(trampoline_stub) \ 314 315 316 public: 317 enum { 318 value_width = sizeof(unsigned short) * BitsPerByte, 319 type_width = 4, // == log2(type_mask+1) 320 nontype_width = value_width - type_width, 321 datalen_width = nontype_width-1, 322 datalen_tag = 1 << datalen_width, // or-ed into _value 323 datalen_limit = 1 << datalen_width, 324 datalen_mask = (1 << datalen_width)-1 325 }; 326 327 // accessors 328 public: 329 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); } 330 int format() const { return format_mask==0? 0: format_mask & 331 ((unsigned)_value >> offset_width); } 332 int addr_offset() const { assert(!is_prefix(), "must have offset"); 333 return (_value & offset_mask)*offset_unit; } 334 335 protected: 336 const short* data() const { assert(is_datalen(), "must have data"); 337 return (const short*)(this + 1); } 338 int datalen() const { assert(is_datalen(), "must have data"); 339 return (_value & datalen_mask); } 340 int immediate() const { assert(is_immediate(), "must have immed"); 341 return (_value & datalen_mask); } 342 public: 343 static int addr_unit() { return offset_unit; } 344 static int offset_limit() { return (1 << offset_width) * offset_unit; } 345 346 void set_type(relocType type); 347 void set_format(int format); 348 349 void remove() { set_type(none); } 350 351 protected: 352 bool is_none() const { return type() == none; } 353 bool is_prefix() const { return type() == data_prefix_tag; } 354 bool is_datalen() const { assert(is_prefix(), "must be prefix"); 355 return (_value & datalen_tag) != 0; } 356 bool is_immediate() const { assert(is_prefix(), "must be prefix"); 357 return (_value & datalen_tag) == 0; } 358 359 public: 360 // Occasionally records of type relocInfo::none will appear in the stream. 361 // We do not bother to filter these out, but clients should ignore them. 362 // These records serve as "filler" in three ways: 363 // - to skip large spans of unrelocated code (this is rare) 364 // - to pad out the relocInfo array to the required oop alignment 365 // - to disable old relocation information which is no longer applicable 366 367 inline friend relocInfo filler_relocInfo(); 368 369 // Every non-prefix relocation may be preceded by at most one prefix, 370 // which supplies 1 or more halfwords of associated data. Conventionally, 371 // an int is represented by 0, 1, or 2 halfwords, depending on how 372 // many bits are required to represent the value. (In addition, 373 // if the sole halfword is a 10-bit unsigned number, it is made 374 // "immediate" in the prefix header word itself. This optimization 375 // is invisible outside this module.) 376 377 inline friend relocInfo prefix_relocInfo(int datalen); 378 379 protected: 380 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value 381 static relocInfo immediate_relocInfo(int data0) { 382 assert(fits_into_immediate(data0), "data0 in limits"); 383 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0); 384 } 385 static bool fits_into_immediate(int data0) { 386 return (data0 >= 0 && data0 < datalen_limit); 387 } 388 389 public: 390 // Support routines for compilers. 391 392 // This routine takes an infant relocInfo (unprefixed) and 393 // edits in its prefix, if any. It also updates dest.locs_end. 394 void initialize(CodeSection* dest, Relocation* reloc); 395 396 // This routine updates a prefix and returns the limit pointer. 397 // It tries to compress the prefix from 32 to 16 bits, and if 398 // successful returns a reduced "prefix_limit" pointer. 399 relocInfo* finish_prefix(short* prefix_limit); 400 401 // bit-packers for the data array: 402 403 // As it happens, the bytes within the shorts are ordered natively, 404 // but the shorts within the word are ordered big-endian. 405 // This is an arbitrary choice, made this way mainly to ease debugging. 406 static int data0_from_int(jint x) { return x >> value_width; } 407 static int data1_from_int(jint x) { return (short)x; } 408 static jint jint_from_data(short* data) { 409 return (data[0] << value_width) + (unsigned short)data[1]; 410 } 411 412 static jint short_data_at(int n, short* data, int datalen) { 413 return datalen > n ? data[n] : 0; 414 } 415 416 static jint jint_data_at(int n, short* data, int datalen) { 417 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen); 418 } 419 420 // Update methods for relocation information 421 // (since code is dynamically patched, we also need to dynamically update the relocation info) 422 // Both methods takes old_type, so it is able to performe sanity checks on the information removed. 423 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type); 424 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type); 425 426 // Machine dependent stuff 427 #include CPU_HEADER(relocInfo) 428 429 protected: 430 // Derived constant, based on format_width which is PD: 431 enum { 432 offset_width = nontype_width - format_width, 433 offset_mask = (1<<offset_width) - 1, 434 format_mask = (1<<format_width) - 1 435 }; 436 public: 437 enum { 438 #ifdef _LP64 439 // for use in format 440 // format_width must be at least 1 on _LP64 441 narrow_oop_in_const = 1, 442 #endif 443 // Conservatively large estimate of maximum length (in shorts) 444 // of any relocation record. 445 // Extended format is length prefix, data words, and tag/offset suffix. 446 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1, 447 have_format = format_width > 0 448 }; 449 }; 450 451 #define FORWARD_DECLARE_EACH_CLASS(name) \ 452 class name##_Relocation; 453 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS) 454 #undef FORWARD_DECLARE_EACH_CLASS 455 456 457 458 inline relocInfo filler_relocInfo() { 459 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit); 460 } 461 462 inline relocInfo prefix_relocInfo(int datalen = 0) { 463 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits"); 464 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen); 465 } 466 467 468 // Holder for flyweight relocation objects. 469 // Although the flyweight subclasses are of varying sizes, 470 // the holder is "one size fits all". 471 class RelocationHolder { 472 friend class Relocation; 473 friend class CodeSection; 474 475 private: 476 // this preallocated memory must accommodate all subclasses of Relocation 477 // (this number is assertion-checked in Relocation::operator new) 478 enum { _relocbuf_size = 5 }; 479 void* _relocbuf[ _relocbuf_size ]; 480 481 public: 482 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; } 483 inline relocInfo::relocType type() const; 484 485 // Add a constant offset to a relocation. Helper for class Address. 486 RelocationHolder plus(int offset) const; 487 488 inline RelocationHolder(); // initializes type to none 489 490 inline RelocationHolder(Relocation* r); // make a copy 491 492 static const RelocationHolder none; 493 }; 494 495 // A RelocIterator iterates through the relocation information of a CodeBlob. 496 // It is a variable BoundRelocation which is able to take on successive 497 // values as it is advanced through a code stream. 498 // Usage: 499 // RelocIterator iter(nm); 500 // while (iter.next()) { 501 // iter.reloc()->some_operation(); 502 // } 503 // or: 504 // RelocIterator iter(nm); 505 // while (iter.next()) { 506 // switch (iter.type()) { 507 // case relocInfo::oop_type : 508 // case relocInfo::ic_type : 509 // case relocInfo::prim_type : 510 // case relocInfo::uncommon_type : 511 // case relocInfo::runtime_call_type : 512 // case relocInfo::internal_word_type: 513 // case relocInfo::external_word_type: 514 // ... 515 // } 516 // } 517 518 class RelocIterator : public StackObj { 519 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor 520 friend class Relocation; 521 friend class relocInfo; // for change_reloc_info_for_address only 522 typedef relocInfo::relocType relocType; 523 524 private: 525 address _limit; // stop producing relocations after this _addr 526 relocInfo* _current; // the current relocation information 527 relocInfo* _end; // end marker; we're done iterating when _current == _end 528 CompiledMethod* _code; // compiled method containing _addr 529 address _addr; // instruction to which the relocation applies 530 short _databuf; // spare buffer for compressed data 531 short* _data; // pointer to the relocation's data 532 short _datalen; // number of halfwords in _data 533 char _format; // position within the instruction 534 535 // Base addresses needed to compute targets of section_word_type relocs. 536 address _section_start[SECT_LIMIT]; 537 address _section_end [SECT_LIMIT]; 538 539 void set_has_current(bool b) { 540 _datalen = !b ? -1 : 0; 541 debug_only(_data = NULL); 542 } 543 void set_current(relocInfo& ri) { 544 _current = &ri; 545 set_has_current(true); 546 } 547 548 RelocationHolder _rh; // where the current relocation is allocated 549 550 relocInfo* current() const { assert(has_current(), "must have current"); 551 return _current; } 552 553 void set_limits(address begin, address limit); 554 555 void advance_over_prefix(); // helper method 556 557 void initialize_misc(); 558 559 void initialize(CompiledMethod* nm, address begin, address limit); 560 561 RelocIterator() { initialize_misc(); } 562 563 public: 564 // constructor 565 RelocIterator(CompiledMethod* nm, address begin = NULL, address limit = NULL); 566 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL); 567 568 // get next reloc info, return !eos 569 bool next() { 570 _current++; 571 assert(_current <= _end, "must not overrun relocInfo"); 572 if (_current == _end) { 573 set_has_current(false); 574 return false; 575 } 576 set_has_current(true); 577 578 if (_current->is_prefix()) { 579 advance_over_prefix(); 580 assert(!current()->is_prefix(), "only one prefix at a time"); 581 } 582 583 _addr += _current->addr_offset(); 584 585 if (_limit != NULL && _addr >= _limit) { 586 set_has_current(false); 587 return false; 588 } 589 590 if (relocInfo::have_format) _format = current()->format(); 591 return true; 592 } 593 594 // accessors 595 address limit() const { return _limit; } 596 void set_limit(address x); 597 relocType type() const { return current()->type(); } 598 int format() const { return (relocInfo::have_format) ? current()->format() : 0; } 599 address addr() const { return _addr; } 600 CompiledMethod* code() const { return _code; } 601 nmethod* code_as_nmethod() const; 602 short* data() const { return _data; } 603 int datalen() const { return _datalen; } 604 bool has_current() const { return _datalen >= 0; } 605 606 void set_addr(address addr) { _addr = addr; } 607 bool addr_in_const() const; 608 609 address section_start(int n) const { 610 assert(_section_start[n], "must be initialized"); 611 return _section_start[n]; 612 } 613 address section_end(int n) const { 614 assert(_section_end[n], "must be initialized"); 615 return _section_end[n]; 616 } 617 618 // The address points to the affected displacement part of the instruction. 619 // For RISC, this is just the whole instruction. 620 // For Intel, this is an unaligned 32-bit word. 621 622 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc. 623 #define EACH_TYPE(name) \ 624 inline name##_Relocation* name##_reloc(); 625 APPLY_TO_RELOCATIONS(EACH_TYPE) 626 #undef EACH_TYPE 627 // generic relocation accessor; switches on type to call the above 628 Relocation* reloc(); 629 630 #ifndef PRODUCT 631 public: 632 void print(); 633 void print_current(); 634 #endif 635 }; 636 637 638 // A Relocation is a flyweight object allocated within a RelocationHolder. 639 // It represents the relocation data of relocation record. 640 // So, the RelocIterator unpacks relocInfos into Relocations. 641 642 class Relocation { 643 friend class RelocationHolder; 644 friend class RelocIterator; 645 646 private: 647 static void guarantee_size(); 648 649 // When a relocation has been created by a RelocIterator, 650 // this field is non-null. It allows the relocation to know 651 // its context, such as the address to which it applies. 652 RelocIterator* _binding; 653 654 protected: 655 RelocIterator* binding() const { 656 assert(_binding != NULL, "must be bound"); 657 return _binding; 658 } 659 void set_binding(RelocIterator* b) { 660 assert(_binding == NULL, "must be unbound"); 661 _binding = b; 662 assert(_binding != NULL, "must now be bound"); 663 } 664 665 Relocation() { 666 _binding = NULL; 667 } 668 669 static RelocationHolder newHolder() { 670 return RelocationHolder(); 671 } 672 673 public: 674 void* operator new(size_t size, const RelocationHolder& holder) throw() { 675 if (size > sizeof(holder._relocbuf)) guarantee_size(); 676 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree"); 677 return holder.reloc(); 678 } 679 680 // make a generic relocation for a given type (if possible) 681 static RelocationHolder spec_simple(relocInfo::relocType rtype); 682 683 // here is the type-specific hook which writes relocation data: 684 virtual void pack_data_to(CodeSection* dest) { } 685 686 // here is the type-specific hook which reads (unpacks) relocation data: 687 virtual void unpack_data() { 688 assert(datalen()==0 || type()==relocInfo::none, "no data here"); 689 } 690 691 protected: 692 // Helper functions for pack_data_to() and unpack_data(). 693 694 // Most of the compression logic is confined here. 695 // (The "immediate data" mechanism of relocInfo works independently 696 // of this stuff, and acts to further compress most 1-word data prefixes.) 697 698 // A variable-width int is encoded as a short if it will fit in 16 bits. 699 // The decoder looks at datalen to decide whether to unpack short or jint. 700 // Most relocation records are quite simple, containing at most two ints. 701 702 static bool is_short(jint x) { return x == (short)x; } 703 static short* add_short(short* p, int x) { *p++ = x; return p; } 704 static short* add_jint (short* p, jint x) { 705 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x); 706 return p; 707 } 708 static short* add_var_int(short* p, jint x) { // add a variable-width int 709 if (is_short(x)) p = add_short(p, x); 710 else p = add_jint (p, x); 711 return p; 712 } 713 714 static short* pack_1_int_to(short* p, jint x0) { 715 // Format is one of: [] [x] [Xx] 716 if (x0 != 0) p = add_var_int(p, x0); 717 return p; 718 } 719 int unpack_1_int() { 720 assert(datalen() <= 2, "too much data"); 721 return relocInfo::jint_data_at(0, data(), datalen()); 722 } 723 724 // With two ints, the short form is used only if both ints are short. 725 short* pack_2_ints_to(short* p, jint x0, jint x1) { 726 // Format is one of: [] [x y?] [Xx Y?y] 727 if (x0 == 0 && x1 == 0) { 728 // no halfwords needed to store zeroes 729 } else if (is_short(x0) && is_short(x1)) { 730 // 1-2 halfwords needed to store shorts 731 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1); 732 } else { 733 // 3-4 halfwords needed to store jints 734 p = add_jint(p, x0); p = add_var_int(p, x1); 735 } 736 return p; 737 } 738 void unpack_2_ints(jint& x0, jint& x1) { 739 int dlen = datalen(); 740 short* dp = data(); 741 if (dlen <= 2) { 742 x0 = relocInfo::short_data_at(0, dp, dlen); 743 x1 = relocInfo::short_data_at(1, dp, dlen); 744 } else { 745 assert(dlen <= 4, "too much data"); 746 x0 = relocInfo::jint_data_at(0, dp, dlen); 747 x1 = relocInfo::jint_data_at(2, dp, dlen); 748 } 749 } 750 751 protected: 752 // platform-independent utility for patching constant section 753 void const_set_data_value (address x); 754 void const_verify_data_value (address x); 755 // platform-dependent utilities for decoding and patching instructions 756 void pd_set_data_value (address x, intptr_t off, bool verify_only = false); // a set or mem-ref 757 void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); } 758 address pd_call_destination (address orig_addr = NULL); 759 void pd_set_call_destination (address x); 760 761 // this extracts the address of an address in the code stream instead of the reloc data 762 address* pd_address_in_code (); 763 764 // this extracts an address from the code stream instead of the reloc data 765 address pd_get_address_from_code (); 766 767 // these convert from byte offsets, to scaled offsets, to addresses 768 static jint scaled_offset(address x, address base) { 769 int byte_offset = x - base; 770 int offset = -byte_offset / relocInfo::addr_unit(); 771 assert(address_from_scaled_offset(offset, base) == x, "just checkin'"); 772 return offset; 773 } 774 static jint scaled_offset_null_special(address x, address base) { 775 // Some relocations treat offset=0 as meaning NULL. 776 // Handle this extra convention carefully. 777 if (x == NULL) return 0; 778 assert(x != base, "offset must not be zero"); 779 return scaled_offset(x, base); 780 } 781 static address address_from_scaled_offset(jint offset, address base) { 782 int byte_offset = -( offset * relocInfo::addr_unit() ); 783 return base + byte_offset; 784 } 785 786 // helpers for mapping between old and new addresses after a move or resize 787 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest); 788 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest); 789 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false); 790 791 public: 792 // accessors which only make sense for a bound Relocation 793 address addr() const { return binding()->addr(); } 794 CompiledMethod* code() const { return binding()->code(); } 795 nmethod* code_as_nmethod() const { return binding()->code_as_nmethod(); } 796 bool addr_in_const() const { return binding()->addr_in_const(); } 797 protected: 798 short* data() const { return binding()->data(); } 799 int datalen() const { return binding()->datalen(); } 800 int format() const { return binding()->format(); } 801 802 public: 803 virtual relocInfo::relocType type() { return relocInfo::none; } 804 805 // is it a call instruction? 806 virtual bool is_call() { return false; } 807 808 // is it a data movement instruction? 809 virtual bool is_data() { return false; } 810 811 // some relocations can compute their own values 812 virtual address value(); 813 814 // all relocations are able to reassert their values 815 virtual void set_value(address x); 816 817 virtual bool clear_inline_cache() { return true; } 818 819 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and 820 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is 821 // probably a reasonable assumption, since empty caches simplifies code reloacation. 822 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { } 823 }; 824 825 826 // certain inlines must be deferred until class Relocation is defined: 827 828 inline RelocationHolder::RelocationHolder() { 829 // initialize the vtbl, just to keep things type-safe 830 new(*this) Relocation(); 831 } 832 833 834 inline RelocationHolder::RelocationHolder(Relocation* r) { 835 // wordwise copy from r (ok if it copies garbage after r) 836 for (int i = 0; i < _relocbuf_size; i++) { 837 _relocbuf[i] = ((void**)r)[i]; 838 } 839 } 840 841 842 relocInfo::relocType RelocationHolder::type() const { 843 return reloc()->type(); 844 } 845 846 // A DataRelocation always points at a memory or load-constant instruction.. 847 // It is absolute on most machines, and the constant is split on RISCs. 848 // The specific subtypes are oop, external_word, and internal_word. 849 // By convention, the "value" does not include a separately reckoned "offset". 850 class DataRelocation : public Relocation { 851 public: 852 bool is_data() { return true; } 853 854 // both target and offset must be computed somehow from relocation data 855 virtual int offset() { return 0; } 856 address value() = 0; 857 void set_value(address x) { set_value(x, offset()); } 858 void set_value(address x, intptr_t o) { 859 if (addr_in_const()) 860 const_set_data_value(x); 861 else 862 pd_set_data_value(x, o); 863 } 864 void verify_value(address x) { 865 if (addr_in_const()) 866 const_verify_data_value(x); 867 else 868 pd_verify_data_value(x, offset()); 869 } 870 871 // The "o" (displacement) argument is relevant only to split relocations 872 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns 873 // can encode more than 32 bits between them. This allows compilers to 874 // share set-hi instructions between addresses that differ by a small 875 // offset (e.g., different static variables in the same class). 876 // On such machines, the "x" argument to set_value on all set-lo 877 // instructions must be the same as the "x" argument for the 878 // corresponding set-hi instructions. The "o" arguments for the 879 // set-hi instructions are ignored, and must not affect the high-half 880 // immediate constant. The "o" arguments for the set-lo instructions are 881 // added into the low-half immediate constant, and must not overflow it. 882 }; 883 884 // A CallRelocation always points at a call instruction. 885 // It is PC-relative on most machines. 886 class CallRelocation : public Relocation { 887 public: 888 bool is_call() { return true; } 889 890 address destination() { return pd_call_destination(); } 891 void set_destination(address x); // pd_set_call_destination 892 893 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 894 address value() { return destination(); } 895 void set_value(address x) { set_destination(x); } 896 }; 897 898 class oop_Relocation : public DataRelocation { 899 relocInfo::relocType type() { return relocInfo::oop_type; } 900 901 public: 902 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 903 // an oop in the CodeBlob's oop pool 904 static RelocationHolder spec(int oop_index, int offset = 0) { 905 assert(oop_index > 0, "must be a pool-resident oop"); 906 RelocationHolder rh = newHolder(); 907 new(rh) oop_Relocation(oop_index, offset); 908 return rh; 909 } 910 // an oop in the instruction stream 911 static RelocationHolder spec_for_immediate() { 912 // If no immediate oops are generated, we can skip some walks over nmethods. 913 // Assert that they don't get generated accidently! 914 assert(relocInfo::mustIterateImmediateOopsInCode(), 915 "Must return true so we will search for oops as roots etc. in the code."); 916 const int oop_index = 0; 917 const int offset = 0; // if you want an offset, use the oop pool 918 RelocationHolder rh = newHolder(); 919 new(rh) oop_Relocation(oop_index, offset); 920 return rh; 921 } 922 923 private: 924 jint _oop_index; // if > 0, index into CodeBlob::oop_at 925 jint _offset; // byte offset to apply to the oop itself 926 927 oop_Relocation(int oop_index, int offset) { 928 _oop_index = oop_index; _offset = offset; 929 } 930 931 friend class RelocIterator; 932 oop_Relocation() { } 933 934 public: 935 int oop_index() { return _oop_index; } 936 int offset() { return _offset; } 937 938 // data is packed in "2_ints" format: [i o] or [Ii Oo] 939 void pack_data_to(CodeSection* dest); 940 void unpack_data(); 941 942 void fix_oop_relocation(); // reasserts oop value 943 944 void verify_oop_relocation(); 945 946 address value() { return (address) *oop_addr(); } 947 948 bool oop_is_immediate() { return oop_index() == 0; } 949 950 oop* oop_addr(); // addr or &pool[jint_data] 951 oop oop_value(); // *oop_addr 952 // Note: oop_value transparently converts Universe::non_oop_word to NULL. 953 }; 954 955 956 // copy of oop_Relocation for now but may delete stuff in both/either 957 class metadata_Relocation : public DataRelocation { 958 relocInfo::relocType type() { return relocInfo::metadata_type; } 959 960 public: 961 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 962 // an metadata in the CodeBlob's metadata pool 963 static RelocationHolder spec(int metadata_index, int offset = 0) { 964 assert(metadata_index > 0, "must be a pool-resident metadata"); 965 RelocationHolder rh = newHolder(); 966 new(rh) metadata_Relocation(metadata_index, offset); 967 return rh; 968 } 969 // an metadata in the instruction stream 970 static RelocationHolder spec_for_immediate() { 971 const int metadata_index = 0; 972 const int offset = 0; // if you want an offset, use the metadata pool 973 RelocationHolder rh = newHolder(); 974 new(rh) metadata_Relocation(metadata_index, offset); 975 return rh; 976 } 977 978 private: 979 jint _metadata_index; // if > 0, index into nmethod::metadata_at 980 jint _offset; // byte offset to apply to the metadata itself 981 982 metadata_Relocation(int metadata_index, int offset) { 983 _metadata_index = metadata_index; _offset = offset; 984 } 985 986 friend class RelocIterator; 987 metadata_Relocation() { } 988 989 // Fixes a Metadata pointer in the code. Most platforms embeds the 990 // Metadata pointer in the code at compile time so this is empty 991 // for them. 992 void pd_fix_value(address x); 993 994 public: 995 int metadata_index() { return _metadata_index; } 996 int offset() { return _offset; } 997 998 // data is packed in "2_ints" format: [i o] or [Ii Oo] 999 void pack_data_to(CodeSection* dest); 1000 void unpack_data(); 1001 1002 void fix_metadata_relocation(); // reasserts metadata value 1003 1004 void verify_metadata_relocation(); 1005 1006 address value() { return (address) *metadata_addr(); } 1007 1008 bool metadata_is_immediate() { return metadata_index() == 0; } 1009 1010 Metadata** metadata_addr(); // addr or &pool[jint_data] 1011 Metadata* metadata_value(); // *metadata_addr 1012 // Note: metadata_value transparently converts Universe::non_metadata_word to NULL. 1013 }; 1014 1015 1016 class virtual_call_Relocation : public CallRelocation { 1017 relocInfo::relocType type() { return relocInfo::virtual_call_type; } 1018 1019 public: 1020 // "cached_value" points to the first associated set-oop. 1021 // The oop_limit helps find the last associated set-oop. 1022 // (See comments at the top of this file.) 1023 static RelocationHolder spec(address cached_value, jint method_index = 0) { 1024 RelocationHolder rh = newHolder(); 1025 new(rh) virtual_call_Relocation(cached_value, method_index); 1026 return rh; 1027 } 1028 1029 private: 1030 address _cached_value; // location of set-value instruction 1031 jint _method_index; // resolved method for a Java call 1032 1033 virtual_call_Relocation(address cached_value, int method_index) { 1034 _cached_value = cached_value; 1035 _method_index = method_index; 1036 assert(cached_value != NULL, "first oop address must be specified"); 1037 } 1038 1039 friend class RelocIterator; 1040 virtual_call_Relocation() { } 1041 1042 public: 1043 address cached_value(); 1044 1045 int method_index() { return _method_index; } 1046 Method* method_value(); 1047 1048 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll] 1049 // oop_limit is set to 0 if the limit falls somewhere within the call. 1050 // When unpacking, a zero oop_limit is taken to refer to the end of the call. 1051 // (This has the effect of bringing in the call's delay slot on SPARC.) 1052 void pack_data_to(CodeSection* dest); 1053 void unpack_data(); 1054 1055 bool clear_inline_cache(); 1056 }; 1057 1058 1059 class opt_virtual_call_Relocation : public CallRelocation { 1060 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; } 1061 1062 public: 1063 static RelocationHolder spec(int method_index = 0) { 1064 RelocationHolder rh = newHolder(); 1065 new(rh) opt_virtual_call_Relocation(method_index); 1066 return rh; 1067 } 1068 1069 private: 1070 jint _method_index; // resolved method for a Java call 1071 1072 opt_virtual_call_Relocation(int method_index) { 1073 _method_index = method_index; 1074 } 1075 1076 friend class RelocIterator; 1077 opt_virtual_call_Relocation() {} 1078 1079 public: 1080 int method_index() { return _method_index; } 1081 Method* method_value(); 1082 1083 void pack_data_to(CodeSection* dest); 1084 void unpack_data(); 1085 1086 bool clear_inline_cache(); 1087 1088 // find the matching static_stub 1089 address static_stub(bool is_aot); 1090 }; 1091 1092 1093 class static_call_Relocation : public CallRelocation { 1094 relocInfo::relocType type() { return relocInfo::static_call_type; } 1095 1096 public: 1097 static RelocationHolder spec(int method_index = 0) { 1098 RelocationHolder rh = newHolder(); 1099 new(rh) static_call_Relocation(method_index); 1100 return rh; 1101 } 1102 1103 private: 1104 jint _method_index; // resolved method for a Java call 1105 1106 static_call_Relocation(int method_index) { 1107 _method_index = method_index; 1108 } 1109 1110 friend class RelocIterator; 1111 static_call_Relocation() {} 1112 1113 public: 1114 int method_index() { return _method_index; } 1115 Method* method_value(); 1116 1117 void pack_data_to(CodeSection* dest); 1118 void unpack_data(); 1119 1120 bool clear_inline_cache(); 1121 1122 // find the matching static_stub 1123 address static_stub(bool is_aot); 1124 }; 1125 1126 class static_stub_Relocation : public Relocation { 1127 relocInfo::relocType type() { return relocInfo::static_stub_type; } 1128 1129 public: 1130 static RelocationHolder spec(address static_call, bool is_aot = false) { 1131 RelocationHolder rh = newHolder(); 1132 new(rh) static_stub_Relocation(static_call, is_aot); 1133 return rh; 1134 } 1135 1136 private: 1137 address _static_call; // location of corresponding static_call 1138 bool _is_aot; // trampoline to aot code 1139 1140 static_stub_Relocation(address static_call, bool is_aot) { 1141 _static_call = static_call; 1142 _is_aot = is_aot; 1143 } 1144 1145 friend class RelocIterator; 1146 static_stub_Relocation() { } 1147 1148 public: 1149 bool clear_inline_cache(); 1150 1151 address static_call() { return _static_call; } 1152 bool is_aot() { return _is_aot; } 1153 1154 // data is packed as a scaled offset in "1_int" format: [c] or [Cc] 1155 void pack_data_to(CodeSection* dest); 1156 void unpack_data(); 1157 }; 1158 1159 class runtime_call_Relocation : public CallRelocation { 1160 relocInfo::relocType type() { return relocInfo::runtime_call_type; } 1161 1162 public: 1163 static RelocationHolder spec() { 1164 RelocationHolder rh = newHolder(); 1165 new(rh) runtime_call_Relocation(); 1166 return rh; 1167 } 1168 1169 private: 1170 friend class RelocIterator; 1171 runtime_call_Relocation() { } 1172 1173 public: 1174 }; 1175 1176 1177 class runtime_call_w_cp_Relocation : public CallRelocation { 1178 relocInfo::relocType type() { return relocInfo::runtime_call_w_cp_type; } 1179 1180 public: 1181 static RelocationHolder spec() { 1182 RelocationHolder rh = newHolder(); 1183 new(rh) runtime_call_w_cp_Relocation(); 1184 return rh; 1185 } 1186 1187 private: 1188 friend class RelocIterator; 1189 runtime_call_w_cp_Relocation() { _offset = -4; /* <0 = invalid */ } 1190 // On z/Architecture, runtime calls are either a sequence 1191 // of two instructions (load destination of call from constant pool + do call) 1192 // or a pc-relative call. The pc-relative call is faster, but it can only 1193 // be used if the destination of the call is not too far away. 1194 // In order to be able to patch a pc-relative call back into one using 1195 // the constant pool, we have to remember the location of the call's destination 1196 // in the constant pool. 1197 int _offset; 1198 1199 public: 1200 void set_constant_pool_offset(int offset) { _offset = offset; } 1201 int get_constant_pool_offset() { return _offset; } 1202 void pack_data_to(CodeSection * dest); 1203 void unpack_data(); 1204 }; 1205 1206 // Trampoline Relocations. 1207 // A trampoline allows to encode a small branch in the code, even if there 1208 // is the chance that this branch can not reach all possible code locations. 1209 // If the relocation finds that a branch is too far for the instruction 1210 // in the code, it can patch it to jump to the trampoline where is 1211 // sufficient space for a far branch. Needed on PPC. 1212 class trampoline_stub_Relocation : public Relocation { 1213 relocInfo::relocType type() { return relocInfo::trampoline_stub_type; } 1214 1215 public: 1216 static RelocationHolder spec(address static_call) { 1217 RelocationHolder rh = newHolder(); 1218 return (new (rh) trampoline_stub_Relocation(static_call)); 1219 } 1220 1221 private: 1222 address _owner; // Address of the NativeCall that owns the trampoline. 1223 1224 trampoline_stub_Relocation(address owner) { 1225 _owner = owner; 1226 } 1227 1228 friend class RelocIterator; 1229 trampoline_stub_Relocation() { } 1230 1231 public: 1232 1233 // Return the address of the NativeCall that owns the trampoline. 1234 address owner() { return _owner; } 1235 1236 void pack_data_to(CodeSection * dest); 1237 void unpack_data(); 1238 1239 // Find the trampoline stub for a call. 1240 static address get_trampoline_for(address call, nmethod* code); 1241 }; 1242 1243 class external_word_Relocation : public DataRelocation { 1244 relocInfo::relocType type() { return relocInfo::external_word_type; } 1245 1246 public: 1247 static RelocationHolder spec(address target) { 1248 assert(target != NULL, "must not be null"); 1249 RelocationHolder rh = newHolder(); 1250 new(rh) external_word_Relocation(target); 1251 return rh; 1252 } 1253 1254 // Use this one where all 32/64 bits of the target live in the code stream. 1255 // The target must be an intptr_t, and must be absolute (not relative). 1256 static RelocationHolder spec_for_immediate() { 1257 RelocationHolder rh = newHolder(); 1258 new(rh) external_word_Relocation(NULL); 1259 return rh; 1260 } 1261 1262 // Some address looking values aren't safe to treat as relocations 1263 // and should just be treated as constants. 1264 static bool can_be_relocated(address target) { 1265 assert(target == NULL || (uintptr_t)target >= (uintptr_t)os::vm_page_size(), INTPTR_FORMAT, (intptr_t)target); 1266 return target != NULL; 1267 } 1268 1269 private: 1270 address _target; // address in runtime 1271 1272 external_word_Relocation(address target) { 1273 _target = target; 1274 } 1275 1276 friend class RelocIterator; 1277 external_word_Relocation() { } 1278 1279 public: 1280 // data is packed as a well-known address in "1_int" format: [a] or [Aa] 1281 // The function runtime_address_to_index is used to turn full addresses 1282 // to short indexes, if they are pre-registered by the stub mechanism. 1283 // If the "a" value is 0 (i.e., _target is NULL), the address is stored 1284 // in the code stream. See external_word_Relocation::target(). 1285 void pack_data_to(CodeSection* dest); 1286 void unpack_data(); 1287 1288 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1289 address target(); // if _target==NULL, fetch addr from code stream 1290 address value() { return target(); } 1291 }; 1292 1293 class internal_word_Relocation : public DataRelocation { 1294 relocInfo::relocType type() { return relocInfo::internal_word_type; } 1295 1296 public: 1297 static RelocationHolder spec(address target) { 1298 assert(target != NULL, "must not be null"); 1299 RelocationHolder rh = newHolder(); 1300 new(rh) internal_word_Relocation(target); 1301 return rh; 1302 } 1303 1304 // use this one where all the bits of the target can fit in the code stream: 1305 static RelocationHolder spec_for_immediate() { 1306 RelocationHolder rh = newHolder(); 1307 new(rh) internal_word_Relocation(NULL); 1308 return rh; 1309 } 1310 1311 internal_word_Relocation(address target) { 1312 _target = target; 1313 _section = -1; // self-relative 1314 } 1315 1316 protected: 1317 address _target; // address in CodeBlob 1318 int _section; // section providing base address, if any 1319 1320 friend class RelocIterator; 1321 internal_word_Relocation() { } 1322 1323 // bit-width of LSB field in packed offset, if section >= 0 1324 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits 1325 1326 public: 1327 // data is packed as a scaled offset in "1_int" format: [o] or [Oo] 1328 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored 1329 // in the code stream. See internal_word_Relocation::target(). 1330 // If _section is not -1, it is appended to the low bits of the offset. 1331 void pack_data_to(CodeSection* dest); 1332 void unpack_data(); 1333 1334 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1335 address target(); // if _target==NULL, fetch addr from code stream 1336 int section() { return _section; } 1337 address value() { return target(); } 1338 }; 1339 1340 class section_word_Relocation : public internal_word_Relocation { 1341 relocInfo::relocType type() { return relocInfo::section_word_type; } 1342 1343 public: 1344 static RelocationHolder spec(address target, int section) { 1345 RelocationHolder rh = newHolder(); 1346 new(rh) section_word_Relocation(target, section); 1347 return rh; 1348 } 1349 1350 section_word_Relocation(address target, int section) { 1351 assert(target != NULL, "must not be null"); 1352 assert(section >= 0, "must be a valid section"); 1353 _target = target; 1354 _section = section; 1355 } 1356 1357 //void pack_data_to -- inherited 1358 void unpack_data(); 1359 1360 private: 1361 friend class RelocIterator; 1362 section_word_Relocation() { } 1363 }; 1364 1365 1366 class poll_Relocation : public Relocation { 1367 bool is_data() { return true; } 1368 relocInfo::relocType type() { return relocInfo::poll_type; } 1369 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1370 }; 1371 1372 class poll_return_Relocation : public poll_Relocation { 1373 relocInfo::relocType type() { return relocInfo::poll_return_type; } 1374 }; 1375 1376 // We know all the xxx_Relocation classes, so now we can define these: 1377 #define EACH_CASE(name) \ 1378 inline name##_Relocation* RelocIterator::name##_reloc() { \ 1379 assert(type() == relocInfo::name##_type, "type must agree"); \ 1380 /* The purpose of the placed "new" is to re-use the same */ \ 1381 /* stack storage for each new iteration. */ \ 1382 name##_Relocation* r = new(_rh) name##_Relocation(); \ 1383 r->set_binding(this); \ 1384 r->name##_Relocation::unpack_data(); \ 1385 return r; \ 1386 } 1387 APPLY_TO_RELOCATIONS(EACH_CASE); 1388 #undef EACH_CASE 1389 1390 inline RelocIterator::RelocIterator(CompiledMethod* nm, address begin, address limit) { 1391 initialize(nm, begin, limit); 1392 } 1393 1394 #endif // SHARE_VM_CODE_RELOCINFO_HPP