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 "memory/allocation.hpp" 29 #include "runtime/os.hpp" 30 #include "utilities/macros.hpp" 31 32 class nmethod; 33 class CompiledMethod; 34 class Metadata; 35 class NativeMovConstReg; 36 37 // Types in this file: 38 // relocInfo 39 // One element of an array of halfwords encoding compressed relocations. 40 // Also, the source of relocation types (relocInfo::oop_type, ...). 41 // Relocation 42 // A flyweight object representing a single relocation. 43 // It is fully unpacked from the compressed relocation array. 44 // metadata_Relocation, ... (subclasses of Relocation) 45 // The location of some type-specific operations (metadata_addr, ...). 46 // Also, the source of relocation specs (metadata_Relocation::spec, ...). 47 // oop_Relocation, ... (subclasses of Relocation) 48 // oops in the code stream (strings, class loaders) 49 // Also, the source of relocation specs (oop_Relocation::spec, ...). 50 // RelocationHolder 51 // A ValueObj type which acts as a union holding a Relocation object. 52 // Represents a relocation spec passed into a CodeBuffer during assembly. 53 // RelocIterator 54 // A StackObj which iterates over the relocations associated with 55 // a range of code addresses. Can be used to operate a copy of code. 56 // BoundRelocation 57 // An _internal_ type shared by packers and unpackers of relocations. 58 // It pastes together a RelocationHolder with some pointers into 59 // code and relocInfo streams. 60 61 62 // Notes on relocType: 63 // 64 // These hold enough information to read or write a value embedded in 65 // the instructions of an CodeBlob. They're used to update: 66 // 67 // 1) embedded oops (isOop() == true) 68 // 2) inline caches (isIC() == true) 69 // 3) runtime calls (isRuntimeCall() == true) 70 // 4) internal word ref (isInternalWord() == true) 71 // 5) external word ref (isExternalWord() == true) 72 // 73 // when objects move (GC) or if code moves (compacting the code heap). 74 // They are also used to patch the code (if a call site must change) 75 // 76 // A relocInfo is represented in 16 bits: 77 // 4 bits indicating the relocation type 78 // 12 bits indicating the offset from the previous relocInfo address 79 // 80 // The offsets accumulate along the relocInfo stream to encode the 81 // address within the CodeBlob, which is named RelocIterator::addr(). 82 // The address of a particular relocInfo always points to the first 83 // byte of the relevant instruction (and not to any of its subfields 84 // or embedded immediate constants). 85 // 86 // The offset value is scaled appropriately for the target machine. 87 // (See relocInfo_<arch>.hpp for the offset scaling.) 88 // 89 // On some machines, there may also be a "format" field which may provide 90 // additional information about the format of the instruction stream 91 // at the corresponding code address. The format value is usually zero. 92 // Any machine (such as Intel) whose instructions can sometimes contain 93 // more than one relocatable constant needs format codes to distinguish 94 // which operand goes with a given relocation. 95 // 96 // If the target machine needs N format bits, the offset has 12-N bits, 97 // the format is encoded between the offset and the type, and the 98 // relocInfo_<arch>.hpp file has manifest constants for the format codes. 99 // 100 // If the type is "data_prefix_tag" then the offset bits are further encoded, 101 // and in fact represent not a code-stream offset but some inline data. 102 // The data takes the form of a counted sequence of halfwords, which 103 // precedes the actual relocation record. (Clients never see it directly.) 104 // The interpetation of this extra data depends on the relocation type. 105 // 106 // On machines that have 32-bit immediate fields, there is usually 107 // little need for relocation "prefix" data, because the instruction stream 108 // is a perfectly reasonable place to store the value. On machines in 109 // which 32-bit values must be "split" across instructions, the relocation 110 // data is the "true" specification of the value, which is then applied 111 // to some field of the instruction (22 or 13 bits, on SPARC). 112 // 113 // Whenever the location of the CodeBlob changes, any PC-relative 114 // relocations, and any internal_word_type relocations, must be reapplied. 115 // After the GC runs, oop_type relocations must be reapplied. 116 // 117 // 118 // Here are meanings of the types: 119 // 120 // relocInfo::none -- a filler record 121 // Value: none 122 // Instruction: The corresponding code address is ignored 123 // Data: Any data prefix and format code are ignored 124 // (This means that any relocInfo can be disabled by setting 125 // its type to none. See relocInfo::remove.) 126 // 127 // relocInfo::oop_type, relocInfo::metadata_type -- a reference to an oop or meta data 128 // Value: an oop, or else the address (handle) of an oop 129 // Instruction types: memory (load), set (load address) 130 // Data: [] an oop stored in 4 bytes of instruction 131 // [n] n is the index of an oop in the CodeBlob's oop pool 132 // [[N]n l] and l is a byte offset to be applied to the oop 133 // [Nn Ll] both index and offset may be 32 bits if necessary 134 // Here is a special hack, used only by the old compiler: 135 // [[N]n 00] the value is the __address__ of the nth oop in the pool 136 // (Note that the offset allows optimal references to class variables.) 137 // 138 // relocInfo::internal_word_type -- an address within the same CodeBlob 139 // relocInfo::section_word_type -- same, but can refer to another section 140 // Value: an address in the CodeBlob's code or constants section 141 // Instruction types: memory (load), set (load address) 142 // Data: [] stored in 4 bytes of instruction 143 // [[L]l] a relative offset (see [About Offsets] below) 144 // In the case of section_word_type, the offset is relative to a section 145 // base address, and the section number (e.g., SECT_INSTS) is encoded 146 // into the low two bits of the offset L. 147 // 148 // relocInfo::external_word_type -- a fixed address in the runtime system 149 // Value: an address 150 // Instruction types: memory (load), set (load address) 151 // Data: [] stored in 4 bytes of instruction 152 // [n] the index of a "well-known" stub (usual case on RISC) 153 // [Ll] a 32-bit address 154 // 155 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system 156 // Value: an address 157 // Instruction types: PC-relative call (or a PC-relative branch) 158 // Data: [] stored in 4 bytes of instruction 159 // 160 // relocInfo::static_call_type -- a static call 161 // Value: an CodeBlob, a stub, or a fixup routine 162 // Instruction types: a call 163 // Data: [] 164 // The identity of the callee is extracted from debugging information. 165 // //%note reloc_3 166 // 167 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline 168 // cache) 169 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine 170 // Instruction types: a call, plus some associated set-oop instructions 171 // Data: [] the associated set-oops are adjacent to the call 172 // [n] n is a relative offset to the first set-oop 173 // [[N]n l] and l is a limit within which the set-oops occur 174 // [Nn Ll] both n and l may be 32 bits if necessary 175 // The identity of the callee is extracted from debugging information. 176 // 177 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound 178 // 179 // Same info as a static_call_type. We use a special type, so the handling of 180 // virtuals and statics are separated. 181 // 182 // 183 // The offset n points to the first set-oop. (See [About Offsets] below.) 184 // In turn, the set-oop instruction specifies or contains an oop cell devoted 185 // exclusively to the IC call, which can be patched along with the call. 186 // 187 // The locations of any other set-oops are found by searching the relocation 188 // information starting at the first set-oop, and continuing until all 189 // relocations up through l have been inspected. The value l is another 190 // relative offset. (Both n and l are relative to the call's first byte.) 191 // 192 // The limit l of the search is exclusive. However, if it points within 193 // the call (e.g., offset zero), it is adjusted to point after the call and 194 // any associated machine-specific delay slot. 195 // 196 // Since the offsets could be as wide as 32-bits, these conventions 197 // put no restrictions whatever upon code reorganization. 198 // 199 // The compiler is responsible for ensuring that transition from a clean 200 // state to a monomorphic compiled state is MP-safe. This implies that 201 // the system must respond well to intermediate states where a random 202 // subset of the set-oops has been correctly from the clean state 203 // upon entry to the VEP of the compiled method. In the case of a 204 // machine (Intel) with a single set-oop instruction, the 32-bit 205 // immediate field must not straddle a unit of memory coherence. 206 // //%note reloc_3 207 // 208 // relocInfo::static_stub_type -- an extra stub for each static_call_type 209 // Value: none 210 // Instruction types: a virtual call: { set_oop; jump; } 211 // Data: [[N]n] the offset of the associated static_call reloc 212 // This stub becomes the target of a static call which must be upgraded 213 // to a virtual call (because the callee is interpreted). 214 // See [About Offsets] below. 215 // //%note reloc_2 216 // 217 // relocInfo::poll_[return_]type -- a safepoint poll 218 // Value: none 219 // Instruction types: memory load or test 220 // Data: none 221 // 222 // For example: 223 // 224 // INSTRUCTIONS RELOC: TYPE PREFIX DATA 225 // ------------ ---- ----------- 226 // sethi %hi(myObject), R oop_type [n(myObject)] 227 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset] 228 // add R2, 1, R2 229 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset] 230 //%note reloc_1 231 // 232 // This uses 4 instruction words, 8 relocation halfwords, 233 // and an entry (which is sharable) in the CodeBlob's oop pool, 234 // for a total of 36 bytes. 235 // 236 // Note that the compiler is responsible for ensuring the "fldOffset" when 237 // added to "%lo(myObject)" does not overflow the immediate fields of the 238 // memory instructions. 239 // 240 // 241 // [About Offsets] Relative offsets are supplied to this module as 242 // positive byte offsets, but they may be internally stored scaled 243 // and/or negated, depending on what is most compact for the target 244 // system. Since the object pointed to by the offset typically 245 // precedes the relocation address, it is profitable to store 246 // these negative offsets as positive numbers, but this decision 247 // is internal to the relocation information abstractions. 248 // 249 250 class Relocation; 251 class CodeBuffer; 252 class CodeSection; 253 class RelocIterator; 254 255 class relocInfo { 256 friend class RelocIterator; 257 public: 258 enum relocType { 259 none = 0, // Used when no relocation should be generated 260 oop_type = 1, // embedded oop 261 virtual_call_type = 2, // a standard inline cache call for a virtual send 262 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache) 263 static_call_type = 4, // a static send 264 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case) 265 runtime_call_type = 6, // call to fixed external routine 266 external_word_type = 7, // reference to fixed external address 267 internal_word_type = 8, // reference within the current code blob 268 section_word_type = 9, // internal, but a cross-section reference 269 poll_type = 10, // polling instruction for safepoints 270 poll_return_type = 11, // polling instruction for safepoints at return 271 metadata_type = 12, // metadata that used to be oops 272 trampoline_stub_type = 13, // stub-entry for trampoline 273 runtime_call_w_cp_type = 14, // Runtime call which may load its target from the constant pool 274 data_prefix_tag = 15, // tag for a prefix (carries data arguments) 275 type_mask = 15 // A mask which selects only the above values 276 }; 277 278 protected: 279 unsigned short _value; 280 281 enum RawBitsToken { RAW_BITS }; 282 relocInfo(relocType type, RawBitsToken ignore, int bits) 283 : _value((type << nontype_width) + bits) { } 284 285 relocInfo(relocType type, RawBitsToken ignore, int off, int f) 286 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { } 287 288 public: 289 // constructor 290 relocInfo(relocType type, int offset, int format = 0) 291 #ifndef ASSERT 292 { 293 (*this) = relocInfo(type, RAW_BITS, offset, format); 294 } 295 #else 296 // Put a bunch of assertions out-of-line. 297 ; 298 #endif 299 300 #define APPLY_TO_RELOCATIONS(visitor) \ 301 visitor(oop) \ 302 visitor(metadata) \ 303 visitor(virtual_call) \ 304 visitor(opt_virtual_call) \ 305 visitor(static_call) \ 306 visitor(static_stub) \ 307 visitor(runtime_call) \ 308 visitor(runtime_call_w_cp) \ 309 visitor(external_word) \ 310 visitor(internal_word) \ 311 visitor(poll) \ 312 visitor(poll_return) \ 313 visitor(section_word) \ 314 visitor(trampoline_stub) \ 315 316 317 public: 318 enum { 319 value_width = sizeof(unsigned short) * BitsPerByte, 320 type_width = 4, // == log2(type_mask+1) 321 nontype_width = value_width - type_width, 322 datalen_width = nontype_width-1, 323 datalen_tag = 1 << datalen_width, // or-ed into _value 324 datalen_limit = 1 << datalen_width, 325 datalen_mask = (1 << datalen_width)-1 326 }; 327 328 // accessors 329 public: 330 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); } 331 int format() const { return format_mask==0? 0: format_mask & 332 ((unsigned)_value >> offset_width); } 333 int addr_offset() const { assert(!is_prefix(), "must have offset"); 334 return (_value & offset_mask)*offset_unit; } 335 336 protected: 337 const short* data() const { assert(is_datalen(), "must have data"); 338 return (const short*)(this + 1); } 339 int datalen() const { assert(is_datalen(), "must have data"); 340 return (_value & datalen_mask); } 341 int immediate() const { assert(is_immediate(), "must have immed"); 342 return (_value & datalen_mask); } 343 public: 344 static int addr_unit() { return offset_unit; } 345 static int offset_limit() { return (1 << offset_width) * offset_unit; } 346 347 void set_type(relocType type); 348 void set_format(int format); 349 350 void remove() { set_type(none); } 351 352 protected: 353 bool is_none() const { return type() == none; } 354 bool is_prefix() const { return type() == data_prefix_tag; } 355 bool is_datalen() const { assert(is_prefix(), "must be prefix"); 356 return (_value & datalen_tag) != 0; } 357 bool is_immediate() const { assert(is_prefix(), "must be prefix"); 358 return (_value & datalen_tag) == 0; } 359 360 public: 361 // Occasionally records of type relocInfo::none will appear in the stream. 362 // We do not bother to filter these out, but clients should ignore them. 363 // These records serve as "filler" in three ways: 364 // - to skip large spans of unrelocated code (this is rare) 365 // - to pad out the relocInfo array to the required oop alignment 366 // - to disable old relocation information which is no longer applicable 367 368 inline friend relocInfo filler_relocInfo(); 369 370 // Every non-prefix relocation may be preceded by at most one prefix, 371 // which supplies 1 or more halfwords of associated data. Conventionally, 372 // an int is represented by 0, 1, or 2 halfwords, depending on how 373 // many bits are required to represent the value. (In addition, 374 // if the sole halfword is a 10-bit unsigned number, it is made 375 // "immediate" in the prefix header word itself. This optimization 376 // is invisible outside this module.) 377 378 inline friend relocInfo prefix_relocInfo(int datalen); 379 380 protected: 381 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value 382 static relocInfo immediate_relocInfo(int data0) { 383 assert(fits_into_immediate(data0), "data0 in limits"); 384 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0); 385 } 386 static bool fits_into_immediate(int data0) { 387 return (data0 >= 0 && data0 < datalen_limit); 388 } 389 390 public: 391 // Support routines for compilers. 392 393 // This routine takes an infant relocInfo (unprefixed) and 394 // edits in its prefix, if any. It also updates dest.locs_end. 395 void initialize(CodeSection* dest, Relocation* reloc); 396 397 // This routine updates a prefix and returns the limit pointer. 398 // It tries to compress the prefix from 32 to 16 bits, and if 399 // successful returns a reduced "prefix_limit" pointer. 400 relocInfo* finish_prefix(short* prefix_limit); 401 402 // bit-packers for the data array: 403 404 // As it happens, the bytes within the shorts are ordered natively, 405 // but the shorts within the word are ordered big-endian. 406 // This is an arbitrary choice, made this way mainly to ease debugging. 407 static int data0_from_int(jint x) { return x >> value_width; } 408 static int data1_from_int(jint x) { return (short)x; } 409 static jint jint_from_data(short* data) { 410 return (data[0] << value_width) + (unsigned short)data[1]; 411 } 412 413 static jint short_data_at(int n, short* data, int datalen) { 414 return datalen > n ? data[n] : 0; 415 } 416 417 static jint jint_data_at(int n, short* data, int datalen) { 418 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen); 419 } 420 421 // Update methods for relocation information 422 // (since code is dynamically patched, we also need to dynamically update the relocation info) 423 // Both methods takes old_type, so it is able to performe sanity checks on the information removed. 424 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type); 425 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type); 426 427 // Machine dependent stuff 428 #include CPU_HEADER(relocInfo) 429 430 protected: 431 // Derived constant, based on format_width which is PD: 432 enum { 433 offset_width = nontype_width - format_width, 434 offset_mask = (1<<offset_width) - 1, 435 format_mask = (1<<format_width) - 1 436 }; 437 public: 438 enum { 439 #ifdef _LP64 440 // for use in format 441 // format_width must be at least 1 on _LP64 442 narrow_oop_in_const = 1, 443 #endif 444 // Conservatively large estimate of maximum length (in shorts) 445 // of any relocation record. 446 // Extended format is length prefix, data words, and tag/offset suffix. 447 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1, 448 have_format = format_width > 0 449 }; 450 }; 451 452 #define FORWARD_DECLARE_EACH_CLASS(name) \ 453 class name##_Relocation; 454 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS) 455 #undef FORWARD_DECLARE_EACH_CLASS 456 457 458 459 inline relocInfo filler_relocInfo() { 460 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit); 461 } 462 463 inline relocInfo prefix_relocInfo(int datalen = 0) { 464 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits"); 465 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen); 466 } 467 468 469 // Holder for flyweight relocation objects. 470 // Although the flyweight subclasses are of varying sizes, 471 // the holder is "one size fits all". 472 class RelocationHolder { 473 friend class Relocation; 474 friend class CodeSection; 475 476 private: 477 // this preallocated memory must accommodate all subclasses of Relocation 478 // (this number is assertion-checked in Relocation::operator new) 479 enum { _relocbuf_size = 5 }; 480 void* _relocbuf[ _relocbuf_size ]; 481 482 public: 483 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; } 484 inline relocInfo::relocType type() const; 485 486 // Add a constant offset to a relocation. Helper for class Address. 487 RelocationHolder plus(int offset) const; 488 489 inline RelocationHolder(); // initializes type to none 490 491 inline RelocationHolder(Relocation* r); // make a copy 492 493 static const RelocationHolder none; 494 }; 495 496 // A RelocIterator iterates through the relocation information of a CodeBlob. 497 // It is a variable BoundRelocation which is able to take on successive 498 // values as it is advanced through a code stream. 499 // Usage: 500 // RelocIterator iter(nm); 501 // while (iter.next()) { 502 // iter.reloc()->some_operation(); 503 // } 504 // or: 505 // RelocIterator iter(nm); 506 // while (iter.next()) { 507 // switch (iter.type()) { 508 // case relocInfo::oop_type : 509 // case relocInfo::ic_type : 510 // case relocInfo::prim_type : 511 // case relocInfo::uncommon_type : 512 // case relocInfo::runtime_call_type : 513 // case relocInfo::internal_word_type: 514 // case relocInfo::external_word_type: 515 // ... 516 // } 517 // } 518 519 class RelocIterator : public StackObj { 520 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor 521 friend class Relocation; 522 friend class relocInfo; // for change_reloc_info_for_address only 523 typedef relocInfo::relocType relocType; 524 525 private: 526 address _limit; // stop producing relocations after this _addr 527 relocInfo* _current; // the current relocation information 528 relocInfo* _end; // end marker; we're done iterating when _current == _end 529 CompiledMethod* _code; // compiled method containing _addr 530 address _addr; // instruction to which the relocation applies 531 short _databuf; // spare buffer for compressed data 532 short* _data; // pointer to the relocation's data 533 short _datalen; // number of halfwords in _data 534 char _format; // position within the instruction 535 536 // Base addresses needed to compute targets of section_word_type relocs. 537 address _section_start[SECT_LIMIT]; 538 address _section_end [SECT_LIMIT]; 539 540 void set_has_current(bool b) { 541 _datalen = !b ? -1 : 0; 542 debug_only(_data = NULL); 543 } 544 void set_current(relocInfo& ri) { 545 _current = &ri; 546 set_has_current(true); 547 } 548 549 RelocationHolder _rh; // where the current relocation is allocated 550 551 relocInfo* current() const { assert(has_current(), "must have current"); 552 return _current; } 553 554 void set_limits(address begin, address limit); 555 556 void advance_over_prefix(); // helper method 557 558 void initialize_misc(); 559 560 void initialize(CompiledMethod* nm, address begin, address limit); 561 562 RelocIterator() { initialize_misc(); } 563 564 public: 565 // constructor 566 RelocIterator(CompiledMethod* nm, address begin = NULL, address limit = NULL); 567 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL); 568 569 // get next reloc info, return !eos 570 bool next() { 571 _current++; 572 assert(_current <= _end, "must not overrun relocInfo"); 573 if (_current == _end) { 574 set_has_current(false); 575 return false; 576 } 577 set_has_current(true); 578 579 if (_current->is_prefix()) { 580 advance_over_prefix(); 581 assert(!current()->is_prefix(), "only one prefix at a time"); 582 } 583 584 _addr += _current->addr_offset(); 585 586 if (_limit != NULL && _addr >= _limit) { 587 set_has_current(false); 588 return false; 589 } 590 591 if (relocInfo::have_format) _format = current()->format(); 592 return true; 593 } 594 595 // accessors 596 address limit() const { return _limit; } 597 void set_limit(address x); 598 relocType type() const { return current()->type(); } 599 int format() const { return (relocInfo::have_format) ? current()->format() : 0; } 600 address addr() const { return _addr; } 601 CompiledMethod* code() const { return _code; } 602 nmethod* code_as_nmethod() const; 603 short* data() const { return _data; } 604 int datalen() const { return _datalen; } 605 bool has_current() const { return _datalen >= 0; } 606 607 void set_addr(address addr) { _addr = addr; } 608 bool addr_in_const() const; 609 610 address section_start(int n) const { 611 assert(_section_start[n], "must be initialized"); 612 return _section_start[n]; 613 } 614 address section_end(int n) const { 615 assert(_section_end[n], "must be initialized"); 616 return _section_end[n]; 617 } 618 619 // The address points to the affected displacement part of the instruction. 620 // For RISC, this is just the whole instruction. 621 // For Intel, this is an unaligned 32-bit word. 622 623 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc. 624 #define EACH_TYPE(name) \ 625 inline name##_Relocation* name##_reloc(); 626 APPLY_TO_RELOCATIONS(EACH_TYPE) 627 #undef EACH_TYPE 628 // generic relocation accessor; switches on type to call the above 629 Relocation* reloc(); 630 631 #ifndef PRODUCT 632 public: 633 void print(); 634 void print_current(); 635 #endif 636 }; 637 638 639 // A Relocation is a flyweight object allocated within a RelocationHolder. 640 // It represents the relocation data of relocation record. 641 // So, the RelocIterator unpacks relocInfos into Relocations. 642 643 class Relocation { 644 friend class RelocationHolder; 645 friend class RelocIterator; 646 647 private: 648 static void guarantee_size(); 649 650 // When a relocation has been created by a RelocIterator, 651 // this field is non-null. It allows the relocation to know 652 // its context, such as the address to which it applies. 653 RelocIterator* _binding; 654 655 protected: 656 RelocIterator* binding() const { 657 assert(_binding != NULL, "must be bound"); 658 return _binding; 659 } 660 void set_binding(RelocIterator* b) { 661 assert(_binding == NULL, "must be unbound"); 662 _binding = b; 663 assert(_binding != NULL, "must now be bound"); 664 } 665 666 Relocation() { 667 _binding = NULL; 668 } 669 670 static RelocationHolder newHolder() { 671 return RelocationHolder(); 672 } 673 674 public: 675 void* operator new(size_t size, const RelocationHolder& holder) throw() { 676 if (size > sizeof(holder._relocbuf)) guarantee_size(); 677 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree"); 678 return holder.reloc(); 679 } 680 681 // make a generic relocation for a given type (if possible) 682 static RelocationHolder spec_simple(relocInfo::relocType rtype); 683 684 // here is the type-specific hook which writes relocation data: 685 virtual void pack_data_to(CodeSection* dest) { } 686 687 // here is the type-specific hook which reads (unpacks) relocation data: 688 virtual void unpack_data() { 689 assert(datalen()==0 || type()==relocInfo::none, "no data here"); 690 } 691 692 protected: 693 // Helper functions for pack_data_to() and unpack_data(). 694 695 // Most of the compression logic is confined here. 696 // (The "immediate data" mechanism of relocInfo works independently 697 // of this stuff, and acts to further compress most 1-word data prefixes.) 698 699 // A variable-width int is encoded as a short if it will fit in 16 bits. 700 // The decoder looks at datalen to decide whether to unpack short or jint. 701 // Most relocation records are quite simple, containing at most two ints. 702 703 static bool is_short(jint x) { return x == (short)x; } 704 static short* add_short(short* p, int x) { *p++ = x; return p; } 705 static short* add_jint (short* p, jint x) { 706 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x); 707 return p; 708 } 709 static short* add_var_int(short* p, jint x) { // add a variable-width int 710 if (is_short(x)) p = add_short(p, x); 711 else p = add_jint (p, x); 712 return p; 713 } 714 715 static short* pack_1_int_to(short* p, jint x0) { 716 // Format is one of: [] [x] [Xx] 717 if (x0 != 0) p = add_var_int(p, x0); 718 return p; 719 } 720 int unpack_1_int() { 721 assert(datalen() <= 2, "too much data"); 722 return relocInfo::jint_data_at(0, data(), datalen()); 723 } 724 725 // With two ints, the short form is used only if both ints are short. 726 short* pack_2_ints_to(short* p, jint x0, jint x1) { 727 // Format is one of: [] [x y?] [Xx Y?y] 728 if (x0 == 0 && x1 == 0) { 729 // no halfwords needed to store zeroes 730 } else if (is_short(x0) && is_short(x1)) { 731 // 1-2 halfwords needed to store shorts 732 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1); 733 } else { 734 // 3-4 halfwords needed to store jints 735 p = add_jint(p, x0); p = add_var_int(p, x1); 736 } 737 return p; 738 } 739 void unpack_2_ints(jint& x0, jint& x1) { 740 int dlen = datalen(); 741 short* dp = data(); 742 if (dlen <= 2) { 743 x0 = relocInfo::short_data_at(0, dp, dlen); 744 x1 = relocInfo::short_data_at(1, dp, dlen); 745 } else { 746 assert(dlen <= 4, "too much data"); 747 x0 = relocInfo::jint_data_at(0, dp, dlen); 748 x1 = relocInfo::jint_data_at(2, dp, dlen); 749 } 750 } 751 752 protected: 753 // platform-independent utility for patching constant section 754 void const_set_data_value (address x); 755 void const_verify_data_value (address x); 756 // platform-dependent utilities for decoding and patching instructions 757 void pd_set_data_value (address x, intptr_t off, bool verify_only = false); // a set or mem-ref 758 void pd_verify_data_value (address x, intptr_t off) { pd_set_data_value(x, off, true); } 759 address pd_call_destination (address orig_addr = NULL); 760 void pd_set_call_destination (address x); 761 762 // this extracts the address of an address in the code stream instead of the reloc data 763 address* pd_address_in_code (); 764 765 // this extracts an address from the code stream instead of the reloc data 766 address pd_get_address_from_code (); 767 768 // these convert from byte offsets, to scaled offsets, to addresses 769 static jint scaled_offset(address x, address base) { 770 int byte_offset = x - base; 771 int offset = -byte_offset / relocInfo::addr_unit(); 772 assert(address_from_scaled_offset(offset, base) == x, "just checkin'"); 773 return offset; 774 } 775 static jint scaled_offset_null_special(address x, address base) { 776 // Some relocations treat offset=0 as meaning NULL. 777 // Handle this extra convention carefully. 778 if (x == NULL) return 0; 779 assert(x != base, "offset must not be zero"); 780 return scaled_offset(x, base); 781 } 782 static address address_from_scaled_offset(jint offset, address base) { 783 int byte_offset = -( offset * relocInfo::addr_unit() ); 784 return base + byte_offset; 785 } 786 787 // helpers for mapping between old and new addresses after a move or resize 788 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest); 789 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest); 790 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false); 791 792 public: 793 // accessors which only make sense for a bound Relocation 794 address addr() const { return binding()->addr(); } 795 CompiledMethod* code() const { return binding()->code(); } 796 nmethod* code_as_nmethod() const { return binding()->code_as_nmethod(); } 797 bool addr_in_const() const { return binding()->addr_in_const(); } 798 protected: 799 short* data() const { return binding()->data(); } 800 int datalen() const { return binding()->datalen(); } 801 int format() const { return binding()->format(); } 802 803 public: 804 virtual relocInfo::relocType type() { return relocInfo::none; } 805 806 // is it a call instruction? 807 virtual bool is_call() { return false; } 808 809 // is it a data movement instruction? 810 virtual bool is_data() { return false; } 811 812 // some relocations can compute their own values 813 virtual address value(); 814 815 // all relocations are able to reassert their values 816 virtual void set_value(address x); 817 818 virtual void clear_inline_cache() { } 819 820 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and 821 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is 822 // probably a reasonable assumption, since empty caches simplifies code reloacation. 823 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { } 824 }; 825 826 827 // certain inlines must be deferred until class Relocation is defined: 828 829 inline RelocationHolder::RelocationHolder() { 830 // initialize the vtbl, just to keep things type-safe 831 new(*this) Relocation(); 832 } 833 834 835 inline RelocationHolder::RelocationHolder(Relocation* r) { 836 // wordwise copy from r (ok if it copies garbage after r) 837 for (int i = 0; i < _relocbuf_size; i++) { 838 _relocbuf[i] = ((void**)r)[i]; 839 } 840 } 841 842 843 relocInfo::relocType RelocationHolder::type() const { 844 return reloc()->type(); 845 } 846 847 // A DataRelocation always points at a memory or load-constant instruction.. 848 // It is absolute on most machines, and the constant is split on RISCs. 849 // The specific subtypes are oop, external_word, and internal_word. 850 // By convention, the "value" does not include a separately reckoned "offset". 851 class DataRelocation : public Relocation { 852 public: 853 bool is_data() { return true; } 854 855 // both target and offset must be computed somehow from relocation data 856 virtual int offset() { return 0; } 857 address value() = 0; 858 void set_value(address x) { set_value(x, offset()); } 859 void set_value(address x, intptr_t o) { 860 if (addr_in_const()) 861 const_set_data_value(x); 862 else 863 pd_set_data_value(x, o); 864 } 865 void verify_value(address x) { 866 if (addr_in_const()) 867 const_verify_data_value(x); 868 else 869 pd_verify_data_value(x, offset()); 870 } 871 872 // The "o" (displacement) argument is relevant only to split relocations 873 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns 874 // can encode more than 32 bits between them. This allows compilers to 875 // share set-hi instructions between addresses that differ by a small 876 // offset (e.g., different static variables in the same class). 877 // On such machines, the "x" argument to set_value on all set-lo 878 // instructions must be the same as the "x" argument for the 879 // corresponding set-hi instructions. The "o" arguments for the 880 // set-hi instructions are ignored, and must not affect the high-half 881 // immediate constant. The "o" arguments for the set-lo instructions are 882 // added into the low-half immediate constant, and must not overflow it. 883 }; 884 885 // A CallRelocation always points at a call instruction. 886 // It is PC-relative on most machines. 887 class CallRelocation : public Relocation { 888 public: 889 bool is_call() { return true; } 890 891 address destination() { return pd_call_destination(); } 892 void set_destination(address x); // pd_set_call_destination 893 894 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 895 address value() { return destination(); } 896 void set_value(address x) { set_destination(x); } 897 }; 898 899 class oop_Relocation : public DataRelocation { 900 relocInfo::relocType type() { return relocInfo::oop_type; } 901 902 public: 903 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 904 // an oop in the CodeBlob's oop pool 905 static RelocationHolder spec(int oop_index, int offset = 0) { 906 assert(oop_index > 0, "must be a pool-resident oop"); 907 RelocationHolder rh = newHolder(); 908 new(rh) oop_Relocation(oop_index, offset); 909 return rh; 910 } 911 // an oop in the instruction stream 912 static RelocationHolder spec_for_immediate() { 913 // If no immediate oops are generated, we can skip some walks over nmethods. 914 // Assert that they don't get generated accidently! 915 assert(relocInfo::mustIterateImmediateOopsInCode(), 916 "Must return true so we will search for oops as roots etc. in the code."); 917 const int oop_index = 0; 918 const int offset = 0; // if you want an offset, use the oop pool 919 RelocationHolder rh = newHolder(); 920 new(rh) oop_Relocation(oop_index, offset); 921 return rh; 922 } 923 924 private: 925 jint _oop_index; // if > 0, index into CodeBlob::oop_at 926 jint _offset; // byte offset to apply to the oop itself 927 928 oop_Relocation(int oop_index, int offset) { 929 _oop_index = oop_index; _offset = offset; 930 } 931 932 friend class RelocIterator; 933 oop_Relocation() { } 934 935 public: 936 int oop_index() { return _oop_index; } 937 int offset() { return _offset; } 938 939 // data is packed in "2_ints" format: [i o] or [Ii Oo] 940 void pack_data_to(CodeSection* dest); 941 void unpack_data(); 942 943 void fix_oop_relocation(); // reasserts oop value 944 945 void verify_oop_relocation(); 946 947 address value() { return (address) *oop_addr(); } 948 949 bool oop_is_immediate() { return oop_index() == 0; } 950 951 oop* oop_addr(); // addr or &pool[jint_data] 952 oop oop_value(); // *oop_addr 953 // Note: oop_value transparently converts Universe::non_oop_word to NULL. 954 }; 955 956 957 // copy of oop_Relocation for now but may delete stuff in both/either 958 class metadata_Relocation : public DataRelocation { 959 relocInfo::relocType type() { return relocInfo::metadata_type; } 960 961 public: 962 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 963 // an metadata in the CodeBlob's metadata pool 964 static RelocationHolder spec(int metadata_index, int offset = 0) { 965 assert(metadata_index > 0, "must be a pool-resident metadata"); 966 RelocationHolder rh = newHolder(); 967 new(rh) metadata_Relocation(metadata_index, offset); 968 return rh; 969 } 970 // an metadata in the instruction stream 971 static RelocationHolder spec_for_immediate() { 972 const int metadata_index = 0; 973 const int offset = 0; // if you want an offset, use the metadata pool 974 RelocationHolder rh = newHolder(); 975 new(rh) metadata_Relocation(metadata_index, offset); 976 return rh; 977 } 978 979 private: 980 jint _metadata_index; // if > 0, index into nmethod::metadata_at 981 jint _offset; // byte offset to apply to the metadata itself 982 983 metadata_Relocation(int metadata_index, int offset) { 984 _metadata_index = metadata_index; _offset = offset; 985 } 986 987 friend class RelocIterator; 988 metadata_Relocation() { } 989 990 // Fixes a Metadata pointer in the code. Most platforms embeds the 991 // Metadata pointer in the code at compile time so this is empty 992 // for them. 993 void pd_fix_value(address x); 994 995 public: 996 int metadata_index() { return _metadata_index; } 997 int offset() { return _offset; } 998 999 // data is packed in "2_ints" format: [i o] or [Ii Oo] 1000 void pack_data_to(CodeSection* dest); 1001 void unpack_data(); 1002 1003 void fix_metadata_relocation(); // reasserts metadata value 1004 1005 void verify_metadata_relocation(); 1006 1007 address value() { return (address) *metadata_addr(); } 1008 1009 bool metadata_is_immediate() { return metadata_index() == 0; } 1010 1011 Metadata** metadata_addr(); // addr or &pool[jint_data] 1012 Metadata* metadata_value(); // *metadata_addr 1013 // Note: metadata_value transparently converts Universe::non_metadata_word to NULL. 1014 }; 1015 1016 1017 class virtual_call_Relocation : public CallRelocation { 1018 relocInfo::relocType type() { return relocInfo::virtual_call_type; } 1019 1020 public: 1021 // "cached_value" points to the first associated set-oop. 1022 // The oop_limit helps find the last associated set-oop. 1023 // (See comments at the top of this file.) 1024 static RelocationHolder spec(address cached_value, jint method_index = 0) { 1025 RelocationHolder rh = newHolder(); 1026 new(rh) virtual_call_Relocation(cached_value, method_index); 1027 return rh; 1028 } 1029 1030 private: 1031 address _cached_value; // location of set-value instruction 1032 jint _method_index; // resolved method for a Java call 1033 1034 virtual_call_Relocation(address cached_value, int method_index) { 1035 _cached_value = cached_value; 1036 _method_index = method_index; 1037 assert(cached_value != NULL, "first oop address must be specified"); 1038 } 1039 1040 friend class RelocIterator; 1041 virtual_call_Relocation() { } 1042 1043 public: 1044 address cached_value(); 1045 1046 int method_index() { return _method_index; } 1047 Method* method_value(); 1048 1049 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll] 1050 // oop_limit is set to 0 if the limit falls somewhere within the call. 1051 // When unpacking, a zero oop_limit is taken to refer to the end of the call. 1052 // (This has the effect of bringing in the call's delay slot on SPARC.) 1053 void pack_data_to(CodeSection* dest); 1054 void unpack_data(); 1055 1056 void clear_inline_cache(); 1057 }; 1058 1059 1060 class opt_virtual_call_Relocation : public CallRelocation { 1061 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; } 1062 1063 public: 1064 static RelocationHolder spec(int method_index = 0) { 1065 RelocationHolder rh = newHolder(); 1066 new(rh) opt_virtual_call_Relocation(method_index); 1067 return rh; 1068 } 1069 1070 private: 1071 jint _method_index; // resolved method for a Java call 1072 1073 opt_virtual_call_Relocation(int method_index) { 1074 _method_index = method_index; 1075 } 1076 1077 friend class RelocIterator; 1078 opt_virtual_call_Relocation() {} 1079 1080 public: 1081 int method_index() { return _method_index; } 1082 Method* method_value(); 1083 1084 void pack_data_to(CodeSection* dest); 1085 void unpack_data(); 1086 1087 void clear_inline_cache(); 1088 1089 // find the matching static_stub 1090 address static_stub(bool is_aot); 1091 }; 1092 1093 1094 class static_call_Relocation : public CallRelocation { 1095 relocInfo::relocType type() { return relocInfo::static_call_type; } 1096 1097 public: 1098 static RelocationHolder spec(int method_index = 0) { 1099 RelocationHolder rh = newHolder(); 1100 new(rh) static_call_Relocation(method_index); 1101 return rh; 1102 } 1103 1104 private: 1105 jint _method_index; // resolved method for a Java call 1106 1107 static_call_Relocation(int method_index) { 1108 _method_index = method_index; 1109 } 1110 1111 friend class RelocIterator; 1112 static_call_Relocation() {} 1113 1114 public: 1115 int method_index() { return _method_index; } 1116 Method* method_value(); 1117 1118 void pack_data_to(CodeSection* dest); 1119 void unpack_data(); 1120 1121 void clear_inline_cache(); 1122 1123 // find the matching static_stub 1124 address static_stub(bool is_aot); 1125 }; 1126 1127 class static_stub_Relocation : public Relocation { 1128 relocInfo::relocType type() { return relocInfo::static_stub_type; } 1129 1130 public: 1131 static RelocationHolder spec(address static_call, bool is_aot = false) { 1132 RelocationHolder rh = newHolder(); 1133 new(rh) static_stub_Relocation(static_call, is_aot); 1134 return rh; 1135 } 1136 1137 private: 1138 address _static_call; // location of corresponding static_call 1139 bool _is_aot; // trampoline to aot code 1140 1141 static_stub_Relocation(address static_call, bool is_aot) { 1142 _static_call = static_call; 1143 _is_aot = is_aot; 1144 } 1145 1146 friend class RelocIterator; 1147 static_stub_Relocation() { } 1148 1149 public: 1150 void clear_inline_cache(); 1151 1152 address static_call() { return _static_call; } 1153 bool is_aot() { return _is_aot; } 1154 1155 // data is packed as a scaled offset in "1_int" format: [c] or [Cc] 1156 void pack_data_to(CodeSection* dest); 1157 void unpack_data(); 1158 }; 1159 1160 class runtime_call_Relocation : public CallRelocation { 1161 relocInfo::relocType type() { return relocInfo::runtime_call_type; } 1162 1163 public: 1164 static RelocationHolder spec() { 1165 RelocationHolder rh = newHolder(); 1166 new(rh) runtime_call_Relocation(); 1167 return rh; 1168 } 1169 1170 private: 1171 friend class RelocIterator; 1172 runtime_call_Relocation() { } 1173 1174 public: 1175 }; 1176 1177 1178 class runtime_call_w_cp_Relocation : public CallRelocation { 1179 relocInfo::relocType type() { return relocInfo::runtime_call_w_cp_type; } 1180 1181 public: 1182 static RelocationHolder spec() { 1183 RelocationHolder rh = newHolder(); 1184 new(rh) runtime_call_w_cp_Relocation(); 1185 return rh; 1186 } 1187 1188 private: 1189 friend class RelocIterator; 1190 runtime_call_w_cp_Relocation() { _offset = -4; /* <0 = invalid */ } 1191 // On z/Architecture, runtime calls are either a sequence 1192 // of two instructions (load destination of call from constant pool + do call) 1193 // or a pc-relative call. The pc-relative call is faster, but it can only 1194 // be used if the destination of the call is not too far away. 1195 // In order to be able to patch a pc-relative call back into one using 1196 // the constant pool, we have to remember the location of the call's destination 1197 // in the constant pool. 1198 int _offset; 1199 1200 public: 1201 void set_constant_pool_offset(int offset) { _offset = offset; } 1202 int get_constant_pool_offset() { return _offset; } 1203 void pack_data_to(CodeSection * dest); 1204 void unpack_data(); 1205 }; 1206 1207 // Trampoline Relocations. 1208 // A trampoline allows to encode a small branch in the code, even if there 1209 // is the chance that this branch can not reach all possible code locations. 1210 // If the relocation finds that a branch is too far for the instruction 1211 // in the code, it can patch it to jump to the trampoline where is 1212 // sufficient space for a far branch. Needed on PPC. 1213 class trampoline_stub_Relocation : public Relocation { 1214 relocInfo::relocType type() { return relocInfo::trampoline_stub_type; } 1215 1216 public: 1217 static RelocationHolder spec(address static_call) { 1218 RelocationHolder rh = newHolder(); 1219 return (new (rh) trampoline_stub_Relocation(static_call)); 1220 } 1221 1222 private: 1223 address _owner; // Address of the NativeCall that owns the trampoline. 1224 1225 trampoline_stub_Relocation(address owner) { 1226 _owner = owner; 1227 } 1228 1229 friend class RelocIterator; 1230 trampoline_stub_Relocation() { } 1231 1232 public: 1233 1234 // Return the address of the NativeCall that owns the trampoline. 1235 address owner() { return _owner; } 1236 1237 void pack_data_to(CodeSection * dest); 1238 void unpack_data(); 1239 1240 // Find the trampoline stub for a call. 1241 static address get_trampoline_for(address call, nmethod* code); 1242 }; 1243 1244 class external_word_Relocation : public DataRelocation { 1245 relocInfo::relocType type() { return relocInfo::external_word_type; } 1246 1247 public: 1248 static RelocationHolder spec(address target) { 1249 assert(target != NULL, "must not be null"); 1250 RelocationHolder rh = newHolder(); 1251 new(rh) external_word_Relocation(target); 1252 return rh; 1253 } 1254 1255 // Use this one where all 32/64 bits of the target live in the code stream. 1256 // The target must be an intptr_t, and must be absolute (not relative). 1257 static RelocationHolder spec_for_immediate() { 1258 RelocationHolder rh = newHolder(); 1259 new(rh) external_word_Relocation(NULL); 1260 return rh; 1261 } 1262 1263 // Some address looking values aren't safe to treat as relocations 1264 // and should just be treated as constants. 1265 static bool can_be_relocated(address target) { 1266 assert(target == NULL || (uintptr_t)target >= (uintptr_t)os::vm_page_size(), INTPTR_FORMAT, (intptr_t)target); 1267 return target != NULL; 1268 } 1269 1270 private: 1271 address _target; // address in runtime 1272 1273 external_word_Relocation(address target) { 1274 _target = target; 1275 } 1276 1277 friend class RelocIterator; 1278 external_word_Relocation() { } 1279 1280 public: 1281 // data is packed as a well-known address in "1_int" format: [a] or [Aa] 1282 // The function runtime_address_to_index is used to turn full addresses 1283 // to short indexes, if they are pre-registered by the stub mechanism. 1284 // If the "a" value is 0 (i.e., _target is NULL), the address is stored 1285 // in the code stream. See external_word_Relocation::target(). 1286 void pack_data_to(CodeSection* dest); 1287 void unpack_data(); 1288 1289 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1290 address target(); // if _target==NULL, fetch addr from code stream 1291 address value() { return target(); } 1292 }; 1293 1294 class internal_word_Relocation : public DataRelocation { 1295 relocInfo::relocType type() { return relocInfo::internal_word_type; } 1296 1297 public: 1298 static RelocationHolder spec(address target) { 1299 assert(target != NULL, "must not be null"); 1300 RelocationHolder rh = newHolder(); 1301 new(rh) internal_word_Relocation(target); 1302 return rh; 1303 } 1304 1305 // use this one where all the bits of the target can fit in the code stream: 1306 static RelocationHolder spec_for_immediate() { 1307 RelocationHolder rh = newHolder(); 1308 new(rh) internal_word_Relocation(NULL); 1309 return rh; 1310 } 1311 1312 internal_word_Relocation(address target) { 1313 _target = target; 1314 _section = -1; // self-relative 1315 } 1316 1317 protected: 1318 address _target; // address in CodeBlob 1319 int _section; // section providing base address, if any 1320 1321 friend class RelocIterator; 1322 internal_word_Relocation() { } 1323 1324 // bit-width of LSB field in packed offset, if section >= 0 1325 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits 1326 1327 public: 1328 // data is packed as a scaled offset in "1_int" format: [o] or [Oo] 1329 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored 1330 // in the code stream. See internal_word_Relocation::target(). 1331 // If _section is not -1, it is appended to the low bits of the offset. 1332 void pack_data_to(CodeSection* dest); 1333 void unpack_data(); 1334 1335 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1336 address target(); // if _target==NULL, fetch addr from code stream 1337 int section() { return _section; } 1338 address value() { return target(); } 1339 }; 1340 1341 class section_word_Relocation : public internal_word_Relocation { 1342 relocInfo::relocType type() { return relocInfo::section_word_type; } 1343 1344 public: 1345 static RelocationHolder spec(address target, int section) { 1346 RelocationHolder rh = newHolder(); 1347 new(rh) section_word_Relocation(target, section); 1348 return rh; 1349 } 1350 1351 section_word_Relocation(address target, int section) { 1352 assert(target != NULL, "must not be null"); 1353 assert(section >= 0, "must be a valid section"); 1354 _target = target; 1355 _section = section; 1356 } 1357 1358 //void pack_data_to -- inherited 1359 void unpack_data(); 1360 1361 private: 1362 friend class RelocIterator; 1363 section_word_Relocation() { } 1364 }; 1365 1366 1367 class poll_Relocation : public Relocation { 1368 bool is_data() { return true; } 1369 relocInfo::relocType type() { return relocInfo::poll_type; } 1370 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1371 }; 1372 1373 class poll_return_Relocation : public poll_Relocation { 1374 relocInfo::relocType type() { return relocInfo::poll_return_type; } 1375 }; 1376 1377 // We know all the xxx_Relocation classes, so now we can define these: 1378 #define EACH_CASE(name) \ 1379 inline name##_Relocation* RelocIterator::name##_reloc() { \ 1380 assert(type() == relocInfo::name##_type, "type must agree"); \ 1381 /* The purpose of the placed "new" is to re-use the same */ \ 1382 /* stack storage for each new iteration. */ \ 1383 name##_Relocation* r = new(_rh) name##_Relocation(); \ 1384 r->set_binding(this); \ 1385 r->name##_Relocation::unpack_data(); \ 1386 return r; \ 1387 } 1388 APPLY_TO_RELOCATIONS(EACH_CASE); 1389 #undef EACH_CASE 1390 1391 inline RelocIterator::RelocIterator(CompiledMethod* nm, address begin, address limit) { 1392 initialize(nm, begin, limit); 1393 } 1394 1395 #endif // SHARE_VM_CODE_RELOCINFO_HPP