1 /* 2 * Copyright (c) 1997, 2010, 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 // Types in this file: 26 // relocInfo 27 // One element of an array of halfwords encoding compressed relocations. 28 // Also, the source of relocation types (relocInfo::oop_type, ...). 29 // Relocation 30 // A flyweight object representing a single relocation. 31 // It is fully unpacked from the compressed relocation array. 32 // oop_Relocation, ... (subclasses of Relocation) 33 // The location of some type-specific operations (oop_addr, ...). 34 // Also, the source of relocation specs (oop_Relocation::spec, ...). 35 // RelocationHolder 36 // A ValueObj type which acts as a union holding a Relocation object. 37 // Represents a relocation spec passed into a CodeBuffer during assembly. 38 // RelocIterator 39 // A StackObj which iterates over the relocations associated with 40 // a range of code addresses. Can be used to operate a copy of code. 41 // PatchingRelocIterator 42 // Specialized subtype of RelocIterator which removes breakpoints 43 // temporarily during iteration, then restores them. 44 // BoundRelocation 45 // An _internal_ type shared by packers and unpackers of relocations. 46 // It pastes together a RelocationHolder with some pointers into 47 // code and relocInfo streams. 48 49 50 // Notes on relocType: 51 // 52 // These hold enough information to read or write a value embedded in 53 // the instructions of an CodeBlob. They're used to update: 54 // 55 // 1) embedded oops (isOop() == true) 56 // 2) inline caches (isIC() == true) 57 // 3) runtime calls (isRuntimeCall() == true) 58 // 4) internal word ref (isInternalWord() == true) 59 // 5) external word ref (isExternalWord() == true) 60 // 61 // when objects move (GC) or if code moves (compacting the code heap). 62 // They are also used to patch the code (if a call site must change) 63 // 64 // A relocInfo is represented in 16 bits: 65 // 4 bits indicating the relocation type 66 // 12 bits indicating the offset from the previous relocInfo address 67 // 68 // The offsets accumulate along the relocInfo stream to encode the 69 // address within the CodeBlob, which is named RelocIterator::addr(). 70 // The address of a particular relocInfo always points to the first 71 // byte of the relevant instruction (and not to any of its subfields 72 // or embedded immediate constants). 73 // 74 // The offset value is scaled appropriately for the target machine. 75 // (See relocInfo_<arch>.hpp for the offset scaling.) 76 // 77 // On some machines, there may also be a "format" field which may provide 78 // additional information about the format of the instruction stream 79 // at the corresponding code address. The format value is usually zero. 80 // Any machine (such as Intel) whose instructions can sometimes contain 81 // more than one relocatable constant needs format codes to distinguish 82 // which operand goes with a given relocation. 83 // 84 // If the target machine needs N format bits, the offset has 12-N bits, 85 // the format is encoded between the offset and the type, and the 86 // relocInfo_<arch>.hpp file has manifest constants for the format codes. 87 // 88 // If the type is "data_prefix_tag" then the offset bits are further encoded, 89 // and in fact represent not a code-stream offset but some inline data. 90 // The data takes the form of a counted sequence of halfwords, which 91 // precedes the actual relocation record. (Clients never see it directly.) 92 // The interpetation of this extra data depends on the relocation type. 93 // 94 // On machines that have 32-bit immediate fields, there is usually 95 // little need for relocation "prefix" data, because the instruction stream 96 // is a perfectly reasonable place to store the value. On machines in 97 // which 32-bit values must be "split" across instructions, the relocation 98 // data is the "true" specification of the value, which is then applied 99 // to some field of the instruction (22 or 13 bits, on SPARC). 100 // 101 // Whenever the location of the CodeBlob changes, any PC-relative 102 // relocations, and any internal_word_type relocations, must be reapplied. 103 // After the GC runs, oop_type relocations must be reapplied. 104 // 105 // 106 // Here are meanings of the types: 107 // 108 // relocInfo::none -- a filler record 109 // Value: none 110 // Instruction: The corresponding code address is ignored 111 // Data: Any data prefix and format code are ignored 112 // (This means that any relocInfo can be disabled by setting 113 // its type to none. See relocInfo::remove.) 114 // 115 // relocInfo::oop_type -- a reference to an oop 116 // Value: an oop, or else the address (handle) of an oop 117 // Instruction types: memory (load), set (load address) 118 // Data: [] an oop stored in 4 bytes of instruction 119 // [n] n is the index of an oop in the CodeBlob's oop pool 120 // [[N]n l] and l is a byte offset to be applied to the oop 121 // [Nn Ll] both index and offset may be 32 bits if necessary 122 // Here is a special hack, used only by the old compiler: 123 // [[N]n 00] the value is the __address__ of the nth oop in the pool 124 // (Note that the offset allows optimal references to class variables.) 125 // 126 // relocInfo::internal_word_type -- an address within the same CodeBlob 127 // relocInfo::section_word_type -- same, but can refer to another section 128 // Value: an address in the CodeBlob's code or constants section 129 // Instruction types: memory (load), set (load address) 130 // Data: [] stored in 4 bytes of instruction 131 // [[L]l] a relative offset (see [About Offsets] below) 132 // In the case of section_word_type, the offset is relative to a section 133 // base address, and the section number (e.g., SECT_INSTS) is encoded 134 // into the low two bits of the offset L. 135 // 136 // relocInfo::external_word_type -- a fixed address in the runtime system 137 // Value: an address 138 // Instruction types: memory (load), set (load address) 139 // Data: [] stored in 4 bytes of instruction 140 // [n] the index of a "well-known" stub (usual case on RISC) 141 // [Ll] a 32-bit address 142 // 143 // relocInfo::runtime_call_type -- a fixed subroutine in the runtime system 144 // Value: an address 145 // Instruction types: PC-relative call (or a PC-relative branch) 146 // Data: [] stored in 4 bytes of instruction 147 // 148 // relocInfo::static_call_type -- a static call 149 // Value: an CodeBlob, a stub, or a fixup routine 150 // Instruction types: a call 151 // Data: [] 152 // The identity of the callee is extracted from debugging information. 153 // //%note reloc_3 154 // 155 // relocInfo::virtual_call_type -- a virtual call site (which includes an inline 156 // cache) 157 // Value: an CodeBlob, a stub, the interpreter, or a fixup routine 158 // Instruction types: a call, plus some associated set-oop instructions 159 // Data: [] the associated set-oops are adjacent to the call 160 // [n] n is a relative offset to the first set-oop 161 // [[N]n l] and l is a limit within which the set-oops occur 162 // [Nn Ll] both n and l may be 32 bits if necessary 163 // The identity of the callee is extracted from debugging information. 164 // 165 // relocInfo::opt_virtual_call_type -- a virtual call site that is statically bound 166 // 167 // Same info as a static_call_type. We use a special type, so the handling of 168 // virtuals and statics are separated. 169 // 170 // 171 // The offset n points to the first set-oop. (See [About Offsets] below.) 172 // In turn, the set-oop instruction specifies or contains an oop cell devoted 173 // exclusively to the IC call, which can be patched along with the call. 174 // 175 // The locations of any other set-oops are found by searching the relocation 176 // information starting at the first set-oop, and continuing until all 177 // relocations up through l have been inspected. The value l is another 178 // relative offset. (Both n and l are relative to the call's first byte.) 179 // 180 // The limit l of the search is exclusive. However, if it points within 181 // the call (e.g., offset zero), it is adjusted to point after the call and 182 // any associated machine-specific delay slot. 183 // 184 // Since the offsets could be as wide as 32-bits, these conventions 185 // put no restrictions whatever upon code reorganization. 186 // 187 // The compiler is responsible for ensuring that transition from a clean 188 // state to a monomorphic compiled state is MP-safe. This implies that 189 // the system must respond well to intermediate states where a random 190 // subset of the set-oops has been correctly from the clean state 191 // upon entry to the VEP of the compiled method. In the case of a 192 // machine (Intel) with a single set-oop instruction, the 32-bit 193 // immediate field must not straddle a unit of memory coherence. 194 // //%note reloc_3 195 // 196 // relocInfo::breakpoint_type -- a conditional breakpoint in the code 197 // Value: none 198 // Instruction types: any whatsoever 199 // Data: [b [T]t i...] 200 // The b is a bit-packed word representing the breakpoint's attributes. 201 // The t is a target address which the breakpoint calls (when it is enabled). 202 // The i... is a place to store one or two instruction words overwritten 203 // by a trap, so that the breakpoint may be subsequently removed. 204 // 205 // relocInfo::static_stub_type -- an extra stub for each static_call_type 206 // Value: none 207 // Instruction types: a virtual call: { set_oop; jump; } 208 // Data: [[N]n] the offset of the associated static_call reloc 209 // This stub becomes the target of a static call which must be upgraded 210 // to a virtual call (because the callee is interpreted). 211 // See [About Offsets] below. 212 // //%note reloc_2 213 // 214 // For example: 215 // 216 // INSTRUCTIONS RELOC: TYPE PREFIX DATA 217 // ------------ ---- ----------- 218 // sethi %hi(myObject), R oop_type [n(myObject)] 219 // ld [R+%lo(myObject)+fldOffset], R2 oop_type [n(myObject) fldOffset] 220 // add R2, 1, R2 221 // st R2, [R+%lo(myObject)+fldOffset] oop_type [n(myObject) fldOffset] 222 //%note reloc_1 223 // 224 // This uses 4 instruction words, 8 relocation halfwords, 225 // and an entry (which is sharable) in the CodeBlob's oop pool, 226 // for a total of 36 bytes. 227 // 228 // Note that the compiler is responsible for ensuring the "fldOffset" when 229 // added to "%lo(myObject)" does not overflow the immediate fields of the 230 // memory instructions. 231 // 232 // 233 // [About Offsets] Relative offsets are supplied to this module as 234 // positive byte offsets, but they may be internally stored scaled 235 // and/or negated, depending on what is most compact for the target 236 // system. Since the object pointed to by the offset typically 237 // precedes the relocation address, it is profitable to store 238 // these negative offsets as positive numbers, but this decision 239 // is internal to the relocation information abstractions. 240 // 241 242 class Relocation; 243 class CodeBuffer; 244 class CodeSection; 245 class RelocIterator; 246 247 class relocInfo VALUE_OBJ_CLASS_SPEC { 248 friend class RelocIterator; 249 public: 250 enum relocType { 251 none = 0, // Used when no relocation should be generated 252 oop_type = 1, // embedded oop 253 virtual_call_type = 2, // a standard inline cache call for a virtual send 254 opt_virtual_call_type = 3, // a virtual call that has been statically bound (i.e., no IC cache) 255 static_call_type = 4, // a static send 256 static_stub_type = 5, // stub-entry for static send (takes care of interpreter case) 257 runtime_call_type = 6, // call to fixed external routine 258 external_word_type = 7, // reference to fixed external address 259 internal_word_type = 8, // reference within the current code blob 260 section_word_type = 9, // internal, but a cross-section reference 261 poll_type = 10, // polling instruction for safepoints 262 poll_return_type = 11, // polling instruction for safepoints at return 263 breakpoint_type = 12, // an initialization barrier or safepoint 264 yet_unused_type = 13, // Still unused 265 yet_unused_type_2 = 14, // Still unused 266 data_prefix_tag = 15, // tag for a prefix (carries data arguments) 267 type_mask = 15 // A mask which selects only the above values 268 }; 269 270 protected: 271 unsigned short _value; 272 273 enum RawBitsToken { RAW_BITS }; 274 relocInfo(relocType type, RawBitsToken ignore, int bits) 275 : _value((type << nontype_width) + bits) { } 276 277 relocInfo(relocType type, RawBitsToken ignore, int off, int f) 278 : _value((type << nontype_width) + (off / (unsigned)offset_unit) + (f << offset_width)) { } 279 280 public: 281 // constructor 282 relocInfo(relocType type, int offset, int format = 0) 283 #ifndef ASSERT 284 { 285 (*this) = relocInfo(type, RAW_BITS, offset, format); 286 } 287 #else 288 // Put a bunch of assertions out-of-line. 289 ; 290 #endif 291 292 #define APPLY_TO_RELOCATIONS(visitor) \ 293 visitor(oop) \ 294 visitor(virtual_call) \ 295 visitor(opt_virtual_call) \ 296 visitor(static_call) \ 297 visitor(static_stub) \ 298 visitor(runtime_call) \ 299 visitor(external_word) \ 300 visitor(internal_word) \ 301 visitor(poll) \ 302 visitor(poll_return) \ 303 visitor(breakpoint) \ 304 visitor(section_word) \ 305 306 307 public: 308 enum { 309 value_width = sizeof(unsigned short) * BitsPerByte, 310 type_width = 4, // == log2(type_mask+1) 311 nontype_width = value_width - type_width, 312 datalen_width = nontype_width-1, 313 datalen_tag = 1 << datalen_width, // or-ed into _value 314 datalen_limit = 1 << datalen_width, 315 datalen_mask = (1 << datalen_width)-1 316 }; 317 318 // accessors 319 public: 320 relocType type() const { return (relocType)((unsigned)_value >> nontype_width); } 321 int format() const { return format_mask==0? 0: format_mask & 322 ((unsigned)_value >> offset_width); } 323 int addr_offset() const { assert(!is_prefix(), "must have offset"); 324 return (_value & offset_mask)*offset_unit; } 325 326 protected: 327 const short* data() const { assert(is_datalen(), "must have data"); 328 return (const short*)(this + 1); } 329 int datalen() const { assert(is_datalen(), "must have data"); 330 return (_value & datalen_mask); } 331 int immediate() const { assert(is_immediate(), "must have immed"); 332 return (_value & datalen_mask); } 333 public: 334 static int addr_unit() { return offset_unit; } 335 static int offset_limit() { return (1 << offset_width) * offset_unit; } 336 337 void set_type(relocType type); 338 void set_format(int format); 339 340 void remove() { set_type(none); } 341 342 protected: 343 bool is_none() const { return type() == none; } 344 bool is_prefix() const { return type() == data_prefix_tag; } 345 bool is_datalen() const { assert(is_prefix(), "must be prefix"); 346 return (_value & datalen_tag) != 0; } 347 bool is_immediate() const { assert(is_prefix(), "must be prefix"); 348 return (_value & datalen_tag) == 0; } 349 350 public: 351 // Occasionally records of type relocInfo::none will appear in the stream. 352 // We do not bother to filter these out, but clients should ignore them. 353 // These records serve as "filler" in three ways: 354 // - to skip large spans of unrelocated code (this is rare) 355 // - to pad out the relocInfo array to the required oop alignment 356 // - to disable old relocation information which is no longer applicable 357 358 inline friend relocInfo filler_relocInfo(); 359 360 // Every non-prefix relocation may be preceded by at most one prefix, 361 // which supplies 1 or more halfwords of associated data. Conventionally, 362 // an int is represented by 0, 1, or 2 halfwords, depending on how 363 // many bits are required to represent the value. (In addition, 364 // if the sole halfword is a 10-bit unsigned number, it is made 365 // "immediate" in the prefix header word itself. This optimization 366 // is invisible outside this module.) 367 368 inline friend relocInfo prefix_relocInfo(int datalen = 0); 369 370 protected: 371 // an immediate relocInfo optimizes a prefix with one 10-bit unsigned value 372 static relocInfo immediate_relocInfo(int data0) { 373 assert(fits_into_immediate(data0), "data0 in limits"); 374 return relocInfo(relocInfo::data_prefix_tag, RAW_BITS, data0); 375 } 376 static bool fits_into_immediate(int data0) { 377 return (data0 >= 0 && data0 < datalen_limit); 378 } 379 380 public: 381 // Support routines for compilers. 382 383 // This routine takes an infant relocInfo (unprefixed) and 384 // edits in its prefix, if any. It also updates dest.locs_end. 385 void initialize(CodeSection* dest, Relocation* reloc); 386 387 // This routine updates a prefix and returns the limit pointer. 388 // It tries to compress the prefix from 32 to 16 bits, and if 389 // successful returns a reduced "prefix_limit" pointer. 390 relocInfo* finish_prefix(short* prefix_limit); 391 392 // bit-packers for the data array: 393 394 // As it happens, the bytes within the shorts are ordered natively, 395 // but the shorts within the word are ordered big-endian. 396 // This is an arbitrary choice, made this way mainly to ease debugging. 397 static int data0_from_int(jint x) { return x >> value_width; } 398 static int data1_from_int(jint x) { return (short)x; } 399 static jint jint_from_data(short* data) { 400 return (data[0] << value_width) + (unsigned short)data[1]; 401 } 402 403 static jint short_data_at(int n, short* data, int datalen) { 404 return datalen > n ? data[n] : 0; 405 } 406 407 static jint jint_data_at(int n, short* data, int datalen) { 408 return datalen > n+1 ? jint_from_data(&data[n]) : short_data_at(n, data, datalen); 409 } 410 411 // Update methods for relocation information 412 // (since code is dynamically patched, we also need to dynamically update the relocation info) 413 // Both methods takes old_type, so it is able to performe sanity checks on the information removed. 414 static void change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type); 415 static void remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type); 416 417 // Machine dependent stuff 418 #include "incls/_relocInfo_pd.hpp.incl" 419 420 protected: 421 // Derived constant, based on format_width which is PD: 422 enum { 423 offset_width = nontype_width - format_width, 424 offset_mask = (1<<offset_width) - 1, 425 format_mask = (1<<format_width) - 1 426 }; 427 public: 428 enum { 429 // Conservatively large estimate of maximum length (in shorts) 430 // of any relocation record (probably breakpoints are largest). 431 // Extended format is length prefix, data words, and tag/offset suffix. 432 length_limit = 1 + 1 + (3*BytesPerWord/BytesPerShort) + 1, 433 have_format = format_width > 0 434 }; 435 }; 436 437 #define FORWARD_DECLARE_EACH_CLASS(name) \ 438 class name##_Relocation; 439 APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS) 440 #undef FORWARD_DECLARE_EACH_CLASS 441 442 443 444 inline relocInfo filler_relocInfo() { 445 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit); 446 } 447 448 inline relocInfo prefix_relocInfo(int datalen) { 449 assert(relocInfo::fits_into_immediate(datalen), "datalen in limits"); 450 return relocInfo(relocInfo::data_prefix_tag, relocInfo::RAW_BITS, relocInfo::datalen_tag | datalen); 451 } 452 453 454 // Holder for flyweight relocation objects. 455 // Although the flyweight subclasses are of varying sizes, 456 // the holder is "one size fits all". 457 class RelocationHolder VALUE_OBJ_CLASS_SPEC { 458 friend class Relocation; 459 friend class CodeSection; 460 461 private: 462 // this preallocated memory must accommodate all subclasses of Relocation 463 // (this number is assertion-checked in Relocation::operator new) 464 enum { _relocbuf_size = 5 }; 465 void* _relocbuf[ _relocbuf_size ]; 466 467 public: 468 Relocation* reloc() const { return (Relocation*) &_relocbuf[0]; } 469 inline relocInfo::relocType type() const; 470 471 // Add a constant offset to a relocation. Helper for class Address. 472 RelocationHolder plus(int offset) const; 473 474 inline RelocationHolder(); // initializes type to none 475 476 inline RelocationHolder(Relocation* r); // make a copy 477 478 static const RelocationHolder none; 479 }; 480 481 // A RelocIterator iterates through the relocation information of a CodeBlob. 482 // It is a variable BoundRelocation which is able to take on successive 483 // values as it is advanced through a code stream. 484 // Usage: 485 // RelocIterator iter(nm); 486 // while (iter.next()) { 487 // iter.reloc()->some_operation(); 488 // } 489 // or: 490 // RelocIterator iter(nm); 491 // while (iter.next()) { 492 // switch (iter.type()) { 493 // case relocInfo::oop_type : 494 // case relocInfo::ic_type : 495 // case relocInfo::prim_type : 496 // case relocInfo::uncommon_type : 497 // case relocInfo::runtime_call_type : 498 // case relocInfo::internal_word_type: 499 // case relocInfo::external_word_type: 500 // ... 501 // } 502 // } 503 504 class RelocIterator : public StackObj { 505 enum { SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT, checked in ctor 506 friend class Relocation; 507 friend class relocInfo; // for change_reloc_info_for_address only 508 typedef relocInfo::relocType relocType; 509 510 private: 511 address _limit; // stop producing relocations after this _addr 512 relocInfo* _current; // the current relocation information 513 relocInfo* _end; // end marker; we're done iterating when _current == _end 514 nmethod* _code; // compiled method containing _addr 515 address _addr; // instruction to which the relocation applies 516 short _databuf; // spare buffer for compressed data 517 short* _data; // pointer to the relocation's data 518 short _datalen; // number of halfwords in _data 519 char _format; // position within the instruction 520 521 // Base addresses needed to compute targets of section_word_type relocs. 522 address _section_start[SECT_LIMIT]; 523 address _section_end [SECT_LIMIT]; 524 525 void set_has_current(bool b) { 526 _datalen = !b ? -1 : 0; 527 debug_only(_data = NULL); 528 } 529 void set_current(relocInfo& ri) { 530 _current = &ri; 531 set_has_current(true); 532 } 533 534 RelocationHolder _rh; // where the current relocation is allocated 535 536 relocInfo* current() const { assert(has_current(), "must have current"); 537 return _current; } 538 539 void set_limits(address begin, address limit); 540 541 void advance_over_prefix(); // helper method 542 543 void initialize_misc(); 544 545 void initialize(nmethod* nm, address begin, address limit); 546 547 friend class PatchingRelocIterator; 548 // make an uninitialized one, for PatchingRelocIterator: 549 RelocIterator() { initialize_misc(); } 550 551 public: 552 // constructor 553 RelocIterator(nmethod* nm, address begin = NULL, address limit = NULL); 554 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL); 555 556 // get next reloc info, return !eos 557 bool next() { 558 _current++; 559 assert(_current <= _end, "must not overrun relocInfo"); 560 if (_current == _end) { 561 set_has_current(false); 562 return false; 563 } 564 set_has_current(true); 565 566 if (_current->is_prefix()) { 567 advance_over_prefix(); 568 assert(!current()->is_prefix(), "only one prefix at a time"); 569 } 570 571 _addr += _current->addr_offset(); 572 573 if (_limit != NULL && _addr >= _limit) { 574 set_has_current(false); 575 return false; 576 } 577 578 if (relocInfo::have_format) _format = current()->format(); 579 return true; 580 } 581 582 // accessors 583 address limit() const { return _limit; } 584 void set_limit(address x); 585 relocType type() const { return current()->type(); } 586 int format() const { return (relocInfo::have_format) ? current()->format() : 0; } 587 address addr() const { return _addr; } 588 nmethod* code() const { return _code; } 589 short* data() const { return _data; } 590 int datalen() const { return _datalen; } 591 bool has_current() const { return _datalen >= 0; } 592 593 void set_addr(address addr) { _addr = addr; } 594 bool addr_in_const() const; 595 596 address section_start(int n) const { 597 assert(_section_start[n], "must be initialized"); 598 return _section_start[n]; 599 } 600 address section_end(int n) const { 601 assert(_section_end[n], "must be initialized"); 602 return _section_end[n]; 603 } 604 605 // The address points to the affected displacement part of the instruction. 606 // For RISC, this is just the whole instruction. 607 // For Intel, this is an unaligned 32-bit word. 608 609 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc. 610 #define EACH_TYPE(name) \ 611 inline name##_Relocation* name##_reloc(); 612 APPLY_TO_RELOCATIONS(EACH_TYPE) 613 #undef EACH_TYPE 614 // generic relocation accessor; switches on type to call the above 615 Relocation* reloc(); 616 617 // CodeBlob's have relocation indexes for faster random access: 618 static int locs_and_index_size(int code_size, int locs_size); 619 // Store an index into [dest_start+dest_count..dest_end). 620 // At dest_start[0..dest_count] is the actual relocation information. 621 // Everything else up to dest_end is free space for the index. 622 static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end); 623 624 #ifndef PRODUCT 625 public: 626 void print(); 627 void print_current(); 628 #endif 629 }; 630 631 632 // A Relocation is a flyweight object allocated within a RelocationHolder. 633 // It represents the relocation data of relocation record. 634 // So, the RelocIterator unpacks relocInfos into Relocations. 635 636 class Relocation VALUE_OBJ_CLASS_SPEC { 637 friend class RelocationHolder; 638 friend class RelocIterator; 639 640 private: 641 static void guarantee_size(); 642 643 // When a relocation has been created by a RelocIterator, 644 // this field is non-null. It allows the relocation to know 645 // its context, such as the address to which it applies. 646 RelocIterator* _binding; 647 648 protected: 649 RelocIterator* binding() const { 650 assert(_binding != NULL, "must be bound"); 651 return _binding; 652 } 653 void set_binding(RelocIterator* b) { 654 assert(_binding == NULL, "must be unbound"); 655 _binding = b; 656 assert(_binding != NULL, "must now be bound"); 657 } 658 659 Relocation() { 660 _binding = NULL; 661 } 662 663 static RelocationHolder newHolder() { 664 return RelocationHolder(); 665 } 666 667 public: 668 void* operator new(size_t size, const RelocationHolder& holder) { 669 if (size > sizeof(holder._relocbuf)) guarantee_size(); 670 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree"); 671 return holder.reloc(); 672 } 673 674 // make a generic relocation for a given type (if possible) 675 static RelocationHolder spec_simple(relocInfo::relocType rtype); 676 677 // here is the type-specific hook which writes relocation data: 678 virtual void pack_data_to(CodeSection* dest) { } 679 680 // here is the type-specific hook which reads (unpacks) relocation data: 681 virtual void unpack_data() { 682 assert(datalen()==0 || type()==relocInfo::none, "no data here"); 683 } 684 685 protected: 686 // Helper functions for pack_data_to() and unpack_data(). 687 688 // Most of the compression logic is confined here. 689 // (The "immediate data" mechanism of relocInfo works independently 690 // of this stuff, and acts to further compress most 1-word data prefixes.) 691 692 // A variable-width int is encoded as a short if it will fit in 16 bits. 693 // The decoder looks at datalen to decide whether to unpack short or jint. 694 // Most relocation records are quite simple, containing at most two ints. 695 696 static bool is_short(jint x) { return x == (short)x; } 697 static short* add_short(short* p, int x) { *p++ = x; return p; } 698 static short* add_jint (short* p, jint x) { 699 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x); 700 return p; 701 } 702 static short* add_var_int(short* p, jint x) { // add a variable-width int 703 if (is_short(x)) p = add_short(p, x); 704 else p = add_jint (p, x); 705 return p; 706 } 707 708 static short* pack_1_int_to(short* p, jint x0) { 709 // Format is one of: [] [x] [Xx] 710 if (x0 != 0) p = add_var_int(p, x0); 711 return p; 712 } 713 int unpack_1_int() { 714 assert(datalen() <= 2, "too much data"); 715 return relocInfo::jint_data_at(0, data(), datalen()); 716 } 717 718 // With two ints, the short form is used only if both ints are short. 719 short* pack_2_ints_to(short* p, jint x0, jint x1) { 720 // Format is one of: [] [x y?] [Xx Y?y] 721 if (x0 == 0 && x1 == 0) { 722 // no halfwords needed to store zeroes 723 } else if (is_short(x0) && is_short(x1)) { 724 // 1-2 halfwords needed to store shorts 725 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1); 726 } else { 727 // 3-4 halfwords needed to store jints 728 p = add_jint(p, x0); p = add_var_int(p, x1); 729 } 730 return p; 731 } 732 void unpack_2_ints(jint& x0, jint& x1) { 733 int dlen = datalen(); 734 short* dp = data(); 735 if (dlen <= 2) { 736 x0 = relocInfo::short_data_at(0, dp, dlen); 737 x1 = relocInfo::short_data_at(1, dp, dlen); 738 } else { 739 assert(dlen <= 4, "too much data"); 740 x0 = relocInfo::jint_data_at(0, dp, dlen); 741 x1 = relocInfo::jint_data_at(2, dp, dlen); 742 } 743 } 744 745 protected: 746 // platform-dependent utilities for decoding and patching instructions 747 void pd_set_data_value (address x, intptr_t off); // a set or mem-ref 748 address pd_call_destination (address orig_addr = NULL); 749 void pd_set_call_destination (address x); 750 void pd_swap_in_breakpoint (address x, short* instrs, int instrlen); 751 void pd_swap_out_breakpoint (address x, short* instrs, int instrlen); 752 static int pd_breakpoint_size (); 753 754 // this extracts the address of an address in the code stream instead of the reloc data 755 address* pd_address_in_code (); 756 757 // this extracts an address from the code stream instead of the reloc data 758 address pd_get_address_from_code (); 759 760 // these convert from byte offsets, to scaled offsets, to addresses 761 static jint scaled_offset(address x, address base) { 762 int byte_offset = x - base; 763 int offset = -byte_offset / relocInfo::addr_unit(); 764 assert(address_from_scaled_offset(offset, base) == x, "just checkin'"); 765 return offset; 766 } 767 static jint scaled_offset_null_special(address x, address base) { 768 // Some relocations treat offset=0 as meaning NULL. 769 // Handle this extra convention carefully. 770 if (x == NULL) return 0; 771 assert(x != base, "offset must not be zero"); 772 return scaled_offset(x, base); 773 } 774 static address address_from_scaled_offset(jint offset, address base) { 775 int byte_offset = -( offset * relocInfo::addr_unit() ); 776 return base + byte_offset; 777 } 778 779 // these convert between indexes and addresses in the runtime system 780 static int32_t runtime_address_to_index(address runtime_address); 781 static address index_to_runtime_address(int32_t index); 782 783 // helpers for mapping between old and new addresses after a move or resize 784 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest); 785 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest); 786 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false); 787 788 public: 789 // accessors which only make sense for a bound Relocation 790 address addr() const { return binding()->addr(); } 791 nmethod* code() const { return binding()->code(); } 792 bool addr_in_const() const { return binding()->addr_in_const(); } 793 protected: 794 short* data() const { return binding()->data(); } 795 int datalen() const { return binding()->datalen(); } 796 int format() const { return binding()->format(); } 797 798 public: 799 virtual relocInfo::relocType type() { return relocInfo::none; } 800 801 // is it a call instruction? 802 virtual bool is_call() { return false; } 803 804 // is it a data movement instruction? 805 virtual bool is_data() { return false; } 806 807 // some relocations can compute their own values 808 virtual address value(); 809 810 // all relocations are able to reassert their values 811 virtual void set_value(address x); 812 813 virtual void clear_inline_cache() { } 814 815 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and 816 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is 817 // probably a reasonable assumption, since empty caches simplifies code reloacation. 818 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { } 819 820 void print(); 821 }; 822 823 824 // certain inlines must be deferred until class Relocation is defined: 825 826 inline RelocationHolder::RelocationHolder() { 827 // initialize the vtbl, just to keep things type-safe 828 new(*this) Relocation(); 829 } 830 831 832 inline RelocationHolder::RelocationHolder(Relocation* r) { 833 // wordwise copy from r (ok if it copies garbage after r) 834 for (int i = 0; i < _relocbuf_size; i++) { 835 _relocbuf[i] = ((void**)r)[i]; 836 } 837 } 838 839 840 relocInfo::relocType RelocationHolder::type() const { 841 return reloc()->type(); 842 } 843 844 // A DataRelocation always points at a memory or load-constant instruction.. 845 // It is absolute on most machines, and the constant is split on RISCs. 846 // The specific subtypes are oop, external_word, and internal_word. 847 // By convention, the "value" does not include a separately reckoned "offset". 848 class DataRelocation : public Relocation { 849 public: 850 bool is_data() { return true; } 851 852 // both target and offset must be computed somehow from relocation data 853 virtual int offset() { return 0; } 854 address value() = 0; 855 void set_value(address x) { set_value(x, offset()); } 856 void set_value(address x, intptr_t o) { 857 if (addr_in_const()) 858 *(address*)addr() = x; 859 else 860 pd_set_data_value(x, o); 861 } 862 863 // The "o" (displacement) argument is relevant only to split relocations 864 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns 865 // can encode more than 32 bits between them. This allows compilers to 866 // share set-hi instructions between addresses that differ by a small 867 // offset (e.g., different static variables in the same class). 868 // On such machines, the "x" argument to set_value on all set-lo 869 // instructions must be the same as the "x" argument for the 870 // corresponding set-hi instructions. The "o" arguments for the 871 // set-hi instructions are ignored, and must not affect the high-half 872 // immediate constant. The "o" arguments for the set-lo instructions are 873 // added into the low-half immediate constant, and must not overflow it. 874 }; 875 876 // A CallRelocation always points at a call instruction. 877 // It is PC-relative on most machines. 878 class CallRelocation : public Relocation { 879 public: 880 bool is_call() { return true; } 881 882 address destination() { return pd_call_destination(); } 883 void set_destination(address x); // pd_set_call_destination 884 885 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 886 address value() { return destination(); } 887 void set_value(address x) { set_destination(x); } 888 }; 889 890 class oop_Relocation : public DataRelocation { 891 relocInfo::relocType type() { return relocInfo::oop_type; } 892 893 public: 894 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 895 // an oop in the CodeBlob's oop pool 896 static RelocationHolder spec(int oop_index, int offset = 0) { 897 assert(oop_index > 0, "must be a pool-resident oop"); 898 RelocationHolder rh = newHolder(); 899 new(rh) oop_Relocation(oop_index, offset); 900 return rh; 901 } 902 // an oop in the instruction stream 903 static RelocationHolder spec_for_immediate() { 904 const int oop_index = 0; 905 const int offset = 0; // if you want an offset, use the oop pool 906 RelocationHolder rh = newHolder(); 907 new(rh) oop_Relocation(oop_index, offset); 908 return rh; 909 } 910 911 private: 912 jint _oop_index; // if > 0, index into CodeBlob::oop_at 913 jint _offset; // byte offset to apply to the oop itself 914 915 oop_Relocation(int oop_index, int offset) { 916 _oop_index = oop_index; _offset = offset; 917 } 918 919 friend class RelocIterator; 920 oop_Relocation() { } 921 922 public: 923 int oop_index() { return _oop_index; } 924 int offset() { return _offset; } 925 926 // data is packed in "2_ints" format: [i o] or [Ii Oo] 927 void pack_data_to(CodeSection* dest); 928 void unpack_data(); 929 930 void fix_oop_relocation(); // reasserts oop value 931 932 address value() { return (address) *oop_addr(); } 933 934 bool oop_is_immediate() { return oop_index() == 0; } 935 936 oop* oop_addr(); // addr or &pool[jint_data] 937 oop oop_value(); // *oop_addr 938 // Note: oop_value transparently converts Universe::non_oop_word to NULL. 939 }; 940 941 class virtual_call_Relocation : public CallRelocation { 942 relocInfo::relocType type() { return relocInfo::virtual_call_type; } 943 944 public: 945 // "first_oop" points to the first associated set-oop. 946 // The oop_limit helps find the last associated set-oop. 947 // (See comments at the top of this file.) 948 static RelocationHolder spec(address first_oop, address oop_limit = NULL) { 949 RelocationHolder rh = newHolder(); 950 new(rh) virtual_call_Relocation(first_oop, oop_limit); 951 return rh; 952 } 953 954 virtual_call_Relocation(address first_oop, address oop_limit) { 955 _first_oop = first_oop; _oop_limit = oop_limit; 956 assert(first_oop != NULL, "first oop address must be specified"); 957 } 958 959 private: 960 address _first_oop; // location of first set-oop instruction 961 address _oop_limit; // search limit for set-oop instructions 962 963 friend class RelocIterator; 964 virtual_call_Relocation() { } 965 966 967 public: 968 address first_oop(); 969 address oop_limit(); 970 971 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll] 972 // oop_limit is set to 0 if the limit falls somewhere within the call. 973 // When unpacking, a zero oop_limit is taken to refer to the end of the call. 974 // (This has the effect of bringing in the call's delay slot on SPARC.) 975 void pack_data_to(CodeSection* dest); 976 void unpack_data(); 977 978 void clear_inline_cache(); 979 980 // Figure out where an ic_call is hiding, given a set-oop or call. 981 // Either ic_call or first_oop must be non-null; the other is deduced. 982 // Code if non-NULL must be the nmethod, else it is deduced. 983 // The address of the patchable oop is also deduced. 984 // The returned iterator will enumerate over the oops and the ic_call, 985 // as well as any other relocations that happen to be in that span of code. 986 // Recognize relevant set_oops with: oop_reloc()->oop_addr() == oop_addr. 987 static RelocIterator parse_ic(nmethod* &nm, address &ic_call, address &first_oop, oop* &oop_addr, bool *is_optimized); 988 }; 989 990 991 class opt_virtual_call_Relocation : public CallRelocation { 992 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; } 993 994 public: 995 static RelocationHolder spec() { 996 RelocationHolder rh = newHolder(); 997 new(rh) opt_virtual_call_Relocation(); 998 return rh; 999 } 1000 1001 private: 1002 friend class RelocIterator; 1003 opt_virtual_call_Relocation() { } 1004 1005 public: 1006 void clear_inline_cache(); 1007 1008 // find the matching static_stub 1009 address static_stub(); 1010 }; 1011 1012 1013 class static_call_Relocation : public CallRelocation { 1014 relocInfo::relocType type() { return relocInfo::static_call_type; } 1015 1016 public: 1017 static RelocationHolder spec() { 1018 RelocationHolder rh = newHolder(); 1019 new(rh) static_call_Relocation(); 1020 return rh; 1021 } 1022 1023 private: 1024 friend class RelocIterator; 1025 static_call_Relocation() { } 1026 1027 public: 1028 void clear_inline_cache(); 1029 1030 // find the matching static_stub 1031 address static_stub(); 1032 }; 1033 1034 class static_stub_Relocation : public Relocation { 1035 relocInfo::relocType type() { return relocInfo::static_stub_type; } 1036 1037 public: 1038 static RelocationHolder spec(address static_call) { 1039 RelocationHolder rh = newHolder(); 1040 new(rh) static_stub_Relocation(static_call); 1041 return rh; 1042 } 1043 1044 private: 1045 address _static_call; // location of corresponding static_call 1046 1047 static_stub_Relocation(address static_call) { 1048 _static_call = static_call; 1049 } 1050 1051 friend class RelocIterator; 1052 static_stub_Relocation() { } 1053 1054 public: 1055 void clear_inline_cache(); 1056 1057 address static_call() { return _static_call; } 1058 1059 // data is packed as a scaled offset in "1_int" format: [c] or [Cc] 1060 void pack_data_to(CodeSection* dest); 1061 void unpack_data(); 1062 }; 1063 1064 class runtime_call_Relocation : public CallRelocation { 1065 relocInfo::relocType type() { return relocInfo::runtime_call_type; } 1066 1067 public: 1068 static RelocationHolder spec() { 1069 RelocationHolder rh = newHolder(); 1070 new(rh) runtime_call_Relocation(); 1071 return rh; 1072 } 1073 1074 private: 1075 friend class RelocIterator; 1076 runtime_call_Relocation() { } 1077 1078 public: 1079 }; 1080 1081 class external_word_Relocation : public DataRelocation { 1082 relocInfo::relocType type() { return relocInfo::external_word_type; } 1083 1084 public: 1085 static RelocationHolder spec(address target) { 1086 assert(target != NULL, "must not be null"); 1087 RelocationHolder rh = newHolder(); 1088 new(rh) external_word_Relocation(target); 1089 return rh; 1090 } 1091 1092 // Use this one where all 32/64 bits of the target live in the code stream. 1093 // The target must be an intptr_t, and must be absolute (not relative). 1094 static RelocationHolder spec_for_immediate() { 1095 RelocationHolder rh = newHolder(); 1096 new(rh) external_word_Relocation(NULL); 1097 return rh; 1098 } 1099 1100 private: 1101 address _target; // address in runtime 1102 1103 external_word_Relocation(address target) { 1104 _target = target; 1105 } 1106 1107 friend class RelocIterator; 1108 external_word_Relocation() { } 1109 1110 public: 1111 // data is packed as a well-known address in "1_int" format: [a] or [Aa] 1112 // The function runtime_address_to_index is used to turn full addresses 1113 // to short indexes, if they are pre-registered by the stub mechanism. 1114 // If the "a" value is 0 (i.e., _target is NULL), the address is stored 1115 // in the code stream. See external_word_Relocation::target(). 1116 void pack_data_to(CodeSection* dest); 1117 void unpack_data(); 1118 1119 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1120 address target(); // if _target==NULL, fetch addr from code stream 1121 address value() { return target(); } 1122 }; 1123 1124 class internal_word_Relocation : public DataRelocation { 1125 relocInfo::relocType type() { return relocInfo::internal_word_type; } 1126 1127 public: 1128 static RelocationHolder spec(address target) { 1129 assert(target != NULL, "must not be null"); 1130 RelocationHolder rh = newHolder(); 1131 new(rh) internal_word_Relocation(target); 1132 return rh; 1133 } 1134 1135 // use this one where all the bits of the target can fit in the code stream: 1136 static RelocationHolder spec_for_immediate() { 1137 RelocationHolder rh = newHolder(); 1138 new(rh) internal_word_Relocation(NULL); 1139 return rh; 1140 } 1141 1142 internal_word_Relocation(address target) { 1143 _target = target; 1144 _section = -1; // self-relative 1145 } 1146 1147 protected: 1148 address _target; // address in CodeBlob 1149 int _section; // section providing base address, if any 1150 1151 friend class RelocIterator; 1152 internal_word_Relocation() { } 1153 1154 // bit-width of LSB field in packed offset, if section >= 0 1155 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits 1156 1157 public: 1158 // data is packed as a scaled offset in "1_int" format: [o] or [Oo] 1159 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored 1160 // in the code stream. See internal_word_Relocation::target(). 1161 // If _section is not -1, it is appended to the low bits of the offset. 1162 void pack_data_to(CodeSection* dest); 1163 void unpack_data(); 1164 1165 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1166 address target(); // if _target==NULL, fetch addr from code stream 1167 int section() { return _section; } 1168 address value() { return target(); } 1169 }; 1170 1171 class section_word_Relocation : public internal_word_Relocation { 1172 relocInfo::relocType type() { return relocInfo::section_word_type; } 1173 1174 public: 1175 static RelocationHolder spec(address target, int section) { 1176 RelocationHolder rh = newHolder(); 1177 new(rh) section_word_Relocation(target, section); 1178 return rh; 1179 } 1180 1181 section_word_Relocation(address target, int section) { 1182 assert(target != NULL, "must not be null"); 1183 assert(section >= 0, "must be a valid section"); 1184 _target = target; 1185 _section = section; 1186 } 1187 1188 //void pack_data_to -- inherited 1189 void unpack_data(); 1190 1191 private: 1192 friend class RelocIterator; 1193 section_word_Relocation() { } 1194 }; 1195 1196 1197 class poll_Relocation : public Relocation { 1198 bool is_data() { return true; } 1199 relocInfo::relocType type() { return relocInfo::poll_type; } 1200 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1201 }; 1202 1203 class poll_return_Relocation : public Relocation { 1204 bool is_data() { return true; } 1205 relocInfo::relocType type() { return relocInfo::poll_return_type; } 1206 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1207 }; 1208 1209 1210 class breakpoint_Relocation : public Relocation { 1211 relocInfo::relocType type() { return relocInfo::breakpoint_type; } 1212 1213 enum { 1214 // attributes which affect the interpretation of the data: 1215 removable_attr = 0x0010, // buffer [i...] allows for undoing the trap 1216 internal_attr = 0x0020, // the target is an internal addr (local stub) 1217 settable_attr = 0x0040, // the target is settable 1218 1219 // states which can change over time: 1220 enabled_state = 0x0100, // breakpoint must be active in running code 1221 active_state = 0x0200, // breakpoint instruction actually in code 1222 1223 kind_mask = 0x000F, // mask for extracting kind 1224 high_bit = 0x4000 // extra bit which is always set 1225 }; 1226 1227 public: 1228 enum { 1229 // kinds: 1230 initialization = 1, 1231 safepoint = 2 1232 }; 1233 1234 // If target is NULL, 32 bits are reserved for a later set_target(). 1235 static RelocationHolder spec(int kind, address target = NULL, bool internal_target = false) { 1236 RelocationHolder rh = newHolder(); 1237 new(rh) breakpoint_Relocation(kind, target, internal_target); 1238 return rh; 1239 } 1240 1241 private: 1242 // We require every bits value to NOT to fit into relocInfo::datalen_width, 1243 // because we are going to actually store state in the reloc, and so 1244 // cannot allow it to be compressed (and hence copied by the iterator). 1245 1246 short _bits; // bit-encoded kind, attrs, & state 1247 address _target; 1248 1249 breakpoint_Relocation(int kind, address target, bool internal_target); 1250 1251 friend class RelocIterator; 1252 breakpoint_Relocation() { } 1253 1254 short bits() const { return _bits; } 1255 short& live_bits() const { return data()[0]; } 1256 short* instrs() const { return data() + datalen() - instrlen(); } 1257 int instrlen() const { return removable() ? pd_breakpoint_size() : 0; } 1258 1259 void set_bits(short x) { 1260 assert(live_bits() == _bits, "must be the only mutator of reloc info"); 1261 live_bits() = _bits = x; 1262 } 1263 1264 public: 1265 address target() const; 1266 void set_target(address x); 1267 1268 int kind() const { return bits() & kind_mask; } 1269 bool enabled() const { return (bits() & enabled_state) != 0; } 1270 bool active() const { return (bits() & active_state) != 0; } 1271 bool internal() const { return (bits() & internal_attr) != 0; } 1272 bool removable() const { return (bits() & removable_attr) != 0; } 1273 bool settable() const { return (bits() & settable_attr) != 0; } 1274 1275 void set_enabled(bool b); // to activate, you must also say set_active 1276 void set_active(bool b); // actually inserts bpt (must be enabled 1st) 1277 1278 // data is packed as 16 bits, followed by the target (1 or 2 words), followed 1279 // if necessary by empty storage for saving away original instruction bytes. 1280 void pack_data_to(CodeSection* dest); 1281 void unpack_data(); 1282 1283 // during certain operations, breakpoints must be out of the way: 1284 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { 1285 assert(!active(), "cannot perform relocation on enabled breakpoints"); 1286 } 1287 }; 1288 1289 1290 // We know all the xxx_Relocation classes, so now we can define these: 1291 #define EACH_CASE(name) \ 1292 inline name##_Relocation* RelocIterator::name##_reloc() { \ 1293 assert(type() == relocInfo::name##_type, "type must agree"); \ 1294 /* The purpose of the placed "new" is to re-use the same */ \ 1295 /* stack storage for each new iteration. */ \ 1296 name##_Relocation* r = new(_rh) name##_Relocation(); \ 1297 r->set_binding(this); \ 1298 r->name##_Relocation::unpack_data(); \ 1299 return r; \ 1300 } 1301 APPLY_TO_RELOCATIONS(EACH_CASE); 1302 #undef EACH_CASE 1303 1304 inline RelocIterator::RelocIterator(nmethod* nm, address begin, address limit) { 1305 initialize(nm, begin, limit); 1306 } 1307 1308 // if you are going to patch code, you should use this subclass of 1309 // RelocIterator 1310 class PatchingRelocIterator : public RelocIterator { 1311 private: 1312 RelocIterator _init_state; 1313 1314 void prepass(); // deactivates all breakpoints 1315 void postpass(); // reactivates all enabled breakpoints 1316 1317 // do not copy these puppies; it would have unpredictable side effects 1318 // these are private and have no bodies defined because they should not be called 1319 PatchingRelocIterator(const RelocIterator&); 1320 void operator=(const RelocIterator&); 1321 1322 public: 1323 PatchingRelocIterator(nmethod* nm, address begin = NULL, address limit = NULL) 1324 : RelocIterator(nm, begin, limit) { prepass(); } 1325 1326 ~PatchingRelocIterator() { postpass(); } 1327 };