relocInfo.hpp revision 304:dc7f315e41f7
1/* 2 * Copyright 1997-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any 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 242class Relocation; 243class CodeBuffer; 244class CodeSection; 245class RelocIterator; 246 247class 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) \ 438class name##_Relocation; 439APPLY_TO_RELOCATIONS(FORWARD_DECLARE_EACH_CLASS) 440#undef FORWARD_DECLARE_EACH_CLASS 441 442 443 444inline relocInfo filler_relocInfo() { 445 return relocInfo(relocInfo::none, relocInfo::offset_limit() - relocInfo::offset_unit); 446} 447 448inline 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". 457class 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 504class RelocIterator : public StackObj { 505 enum { SECT_CONSTS = 2, 506 SECT_LIMIT = 3 }; // must be equal to CodeBuffer::SECT_LIMIT 507 friend class Relocation; 508 friend class relocInfo; // for change_reloc_info_for_address only 509 typedef relocInfo::relocType relocType; 510 511 private: 512 address _limit; // stop producing relocations after this _addr 513 relocInfo* _current; // the current relocation information 514 relocInfo* _end; // end marker; we're done iterating when _current == _end 515 CodeBlob* _code; // compiled method containing _addr 516 address _addr; // instruction to which the relocation applies 517 short _databuf; // spare buffer for compressed data 518 short* _data; // pointer to the relocation's data 519 short _datalen; // number of halfwords in _data 520 char _format; // position within the instruction 521 522 // Base addresses needed to compute targets of section_word_type relocs. 523 address _section_start[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 set_has_current(false); 545 for (int i = 0; i < SECT_LIMIT; i++) { 546 _section_start[i] = NULL; // these will be lazily computed, if needed 547 } 548 } 549 550 address compute_section_start(int n) const; // out-of-line helper 551 552 void initialize(CodeBlob* nm, address begin, address limit); 553 554 friend class PatchingRelocIterator; 555 // make an uninitialized one, for PatchingRelocIterator: 556 RelocIterator() { initialize_misc(); } 557 558 public: 559 // constructor 560 RelocIterator(CodeBlob* cb, address begin = NULL, address limit = NULL); 561 RelocIterator(CodeSection* cb, address begin = NULL, address limit = NULL); 562 563 // get next reloc info, return !eos 564 bool next() { 565 _current++; 566 assert(_current <= _end, "must not overrun relocInfo"); 567 if (_current == _end) { 568 set_has_current(false); 569 return false; 570 } 571 set_has_current(true); 572 573 if (_current->is_prefix()) { 574 advance_over_prefix(); 575 assert(!current()->is_prefix(), "only one prefix at a time"); 576 } 577 578 _addr += _current->addr_offset(); 579 580 if (_limit != NULL && _addr >= _limit) { 581 set_has_current(false); 582 return false; 583 } 584 585 if (relocInfo::have_format) _format = current()->format(); 586 return true; 587 } 588 589 // accessors 590 address limit() const { return _limit; } 591 void set_limit(address x); 592 relocType type() const { return current()->type(); } 593 int format() const { return (relocInfo::have_format) ? current()->format() : 0; } 594 address addr() const { return _addr; } 595 CodeBlob* code() const { return _code; } 596 short* data() const { return _data; } 597 int datalen() const { return _datalen; } 598 bool has_current() const { return _datalen >= 0; } 599 600 void set_addr(address addr) { _addr = addr; } 601 bool addr_in_const() const { return addr() >= section_start(SECT_CONSTS); } 602 603 address section_start(int n) const { 604 address res = _section_start[n]; 605 return (res != NULL) ? res : compute_section_start(n); 606 } 607 608 // The address points to the affected displacement part of the instruction. 609 // For RISC, this is just the whole instruction. 610 // For Intel, this is an unaligned 32-bit word. 611 612 // type-specific relocation accessors: oop_Relocation* oop_reloc(), etc. 613 #define EACH_TYPE(name) \ 614 inline name##_Relocation* name##_reloc(); 615 APPLY_TO_RELOCATIONS(EACH_TYPE) 616 #undef EACH_TYPE 617 // generic relocation accessor; switches on type to call the above 618 Relocation* reloc(); 619 620 // CodeBlob's have relocation indexes for faster random access: 621 static int locs_and_index_size(int code_size, int locs_size); 622 // Store an index into [dest_start+dest_count..dest_end). 623 // At dest_start[0..dest_count] is the actual relocation information. 624 // Everything else up to dest_end is free space for the index. 625 static void create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end); 626 627#ifndef PRODUCT 628 public: 629 void print(); 630 void print_current(); 631#endif 632}; 633 634 635// A Relocation is a flyweight object allocated within a RelocationHolder. 636// It represents the relocation data of relocation record. 637// So, the RelocIterator unpacks relocInfos into Relocations. 638 639class Relocation VALUE_OBJ_CLASS_SPEC { 640 friend class RelocationHolder; 641 friend class RelocIterator; 642 643 private: 644 static void guarantee_size(); 645 646 // When a relocation has been created by a RelocIterator, 647 // this field is non-null. It allows the relocation to know 648 // its context, such as the address to which it applies. 649 RelocIterator* _binding; 650 651 protected: 652 RelocIterator* binding() const { 653 assert(_binding != NULL, "must be bound"); 654 return _binding; 655 } 656 void set_binding(RelocIterator* b) { 657 assert(_binding == NULL, "must be unbound"); 658 _binding = b; 659 assert(_binding != NULL, "must now be bound"); 660 } 661 662 Relocation() { 663 _binding = NULL; 664 } 665 666 static RelocationHolder newHolder() { 667 return RelocationHolder(); 668 } 669 670 public: 671 void* operator new(size_t size, const RelocationHolder& holder) { 672 if (size > sizeof(holder._relocbuf)) guarantee_size(); 673 assert((void* const *)holder.reloc() == &holder._relocbuf[0], "ptrs must agree"); 674 return holder.reloc(); 675 } 676 677 // make a generic relocation for a given type (if possible) 678 static RelocationHolder spec_simple(relocInfo::relocType rtype); 679 680 // here is the type-specific hook which writes relocation data: 681 virtual void pack_data_to(CodeSection* dest) { } 682 683 // here is the type-specific hook which reads (unpacks) relocation data: 684 virtual void unpack_data() { 685 assert(datalen()==0 || type()==relocInfo::none, "no data here"); 686 } 687 688 protected: 689 // Helper functions for pack_data_to() and unpack_data(). 690 691 // Most of the compression logic is confined here. 692 // (The "immediate data" mechanism of relocInfo works independently 693 // of this stuff, and acts to further compress most 1-word data prefixes.) 694 695 // A variable-width int is encoded as a short if it will fit in 16 bits. 696 // The decoder looks at datalen to decide whether to unpack short or jint. 697 // Most relocation records are quite simple, containing at most two ints. 698 699 static bool is_short(jint x) { return x == (short)x; } 700 static short* add_short(short* p, int x) { *p++ = x; return p; } 701 static short* add_jint (short* p, jint x) { 702 *p++ = relocInfo::data0_from_int(x); *p++ = relocInfo::data1_from_int(x); 703 return p; 704 } 705 static short* add_var_int(short* p, jint x) { // add a variable-width int 706 if (is_short(x)) p = add_short(p, x); 707 else p = add_jint (p, x); 708 return p; 709 } 710 711 static short* pack_1_int_to(short* p, jint x0) { 712 // Format is one of: [] [x] [Xx] 713 if (x0 != 0) p = add_var_int(p, x0); 714 return p; 715 } 716 int unpack_1_int() { 717 assert(datalen() <= 2, "too much data"); 718 return relocInfo::jint_data_at(0, data(), datalen()); 719 } 720 721 // With two ints, the short form is used only if both ints are short. 722 short* pack_2_ints_to(short* p, jint x0, jint x1) { 723 // Format is one of: [] [x y?] [Xx Y?y] 724 if (x0 == 0 && x1 == 0) { 725 // no halfwords needed to store zeroes 726 } else if (is_short(x0) && is_short(x1)) { 727 // 1-2 halfwords needed to store shorts 728 p = add_short(p, x0); if (x1!=0) p = add_short(p, x1); 729 } else { 730 // 3-4 halfwords needed to store jints 731 p = add_jint(p, x0); p = add_var_int(p, x1); 732 } 733 return p; 734 } 735 void unpack_2_ints(jint& x0, jint& x1) { 736 int dlen = datalen(); 737 short* dp = data(); 738 if (dlen <= 2) { 739 x0 = relocInfo::short_data_at(0, dp, dlen); 740 x1 = relocInfo::short_data_at(1, dp, dlen); 741 } else { 742 assert(dlen <= 4, "too much data"); 743 x0 = relocInfo::jint_data_at(0, dp, dlen); 744 x1 = relocInfo::jint_data_at(2, dp, dlen); 745 } 746 } 747 748 protected: 749 // platform-dependent utilities for decoding and patching instructions 750 void pd_set_data_value (address x, intptr_t off); // a set or mem-ref 751 address pd_call_destination (address orig_addr = NULL); 752 void pd_set_call_destination (address x); 753 void pd_swap_in_breakpoint (address x, short* instrs, int instrlen); 754 void pd_swap_out_breakpoint (address x, short* instrs, int instrlen); 755 static int pd_breakpoint_size (); 756 757 // this extracts the address of an address in the code stream instead of the reloc data 758 address* pd_address_in_code (); 759 760 // this extracts an address from the code stream instead of the reloc data 761 address pd_get_address_from_code (); 762 763 // these convert from byte offsets, to scaled offsets, to addresses 764 static jint scaled_offset(address x, address base) { 765 int byte_offset = x - base; 766 int offset = -byte_offset / relocInfo::addr_unit(); 767 assert(address_from_scaled_offset(offset, base) == x, "just checkin'"); 768 return offset; 769 } 770 static jint scaled_offset_null_special(address x, address base) { 771 // Some relocations treat offset=0 as meaning NULL. 772 // Handle this extra convention carefully. 773 if (x == NULL) return 0; 774 assert(x != base, "offset must not be zero"); 775 return scaled_offset(x, base); 776 } 777 static address address_from_scaled_offset(jint offset, address base) { 778 int byte_offset = -( offset * relocInfo::addr_unit() ); 779 return base + byte_offset; 780 } 781 782 // these convert between indexes and addresses in the runtime system 783 static int32_t runtime_address_to_index(address runtime_address); 784 static address index_to_runtime_address(int32_t index); 785 786 // helpers for mapping between old and new addresses after a move or resize 787 address old_addr_for(address newa, const CodeBuffer* src, CodeBuffer* dest); 788 address new_addr_for(address olda, const CodeBuffer* src, CodeBuffer* dest); 789 void normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections = false); 790 791 public: 792 // accessors which only make sense for a bound Relocation 793 address addr() const { return binding()->addr(); } 794 CodeBlob* code() const { return binding()->code(); } 795 bool addr_in_const() const { return binding()->addr_in_const(); } 796 protected: 797 short* data() const { return binding()->data(); } 798 int datalen() const { return binding()->datalen(); } 799 int format() const { return binding()->format(); } 800 801 public: 802 virtual relocInfo::relocType type() { return relocInfo::none; } 803 804 // is it a call instruction? 805 virtual bool is_call() { return false; } 806 807 // is it a data movement instruction? 808 virtual bool is_data() { return false; } 809 810 // some relocations can compute their own values 811 virtual address value(); 812 813 // all relocations are able to reassert their values 814 virtual void set_value(address x); 815 816 virtual void clear_inline_cache() { } 817 818 // This method assumes that all virtual/static (inline) caches are cleared (since for static_call_type and 819 // ic_call_type is not always posisition dependent (depending on the state of the cache)). However, this is 820 // probably a reasonable assumption, since empty caches simplifies code reloacation. 821 virtual void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { } 822 823 void print(); 824}; 825 826 827// certain inlines must be deferred until class Relocation is defined: 828 829inline RelocationHolder::RelocationHolder() { 830 // initialize the vtbl, just to keep things type-safe 831 new(*this) Relocation(); 832} 833 834 835inline 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 843relocInfo::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". 851class 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 *(address*)addr() = x; 862 else 863 pd_set_data_value(x, o); 864 } 865 866 // The "o" (displacement) argument is relevant only to split relocations 867 // on RISC machines. In some CPUs (SPARC), the set-hi and set-lo ins'ns 868 // can encode more than 32 bits between them. This allows compilers to 869 // share set-hi instructions between addresses that differ by a small 870 // offset (e.g., different static variables in the same class). 871 // On such machines, the "x" argument to set_value on all set-lo 872 // instructions must be the same as the "x" argument for the 873 // corresponding set-hi instructions. The "o" arguments for the 874 // set-hi instructions are ignored, and must not affect the high-half 875 // immediate constant. The "o" arguments for the set-lo instructions are 876 // added into the low-half immediate constant, and must not overflow it. 877}; 878 879// A CallRelocation always points at a call instruction. 880// It is PC-relative on most machines. 881class CallRelocation : public Relocation { 882 public: 883 bool is_call() { return true; } 884 885 address destination() { return pd_call_destination(); } 886 void set_destination(address x); // pd_set_call_destination 887 888 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 889 address value() { return destination(); } 890 void set_value(address x) { set_destination(x); } 891}; 892 893class oop_Relocation : public DataRelocation { 894 relocInfo::relocType type() { return relocInfo::oop_type; } 895 896 public: 897 // encode in one of these formats: [] [n] [n l] [Nn l] [Nn Ll] 898 // an oop in the CodeBlob's oop pool 899 static RelocationHolder spec(int oop_index, int offset = 0) { 900 assert(oop_index > 0, "must be a pool-resident oop"); 901 RelocationHolder rh = newHolder(); 902 new(rh) oop_Relocation(oop_index, offset); 903 return rh; 904 } 905 // an oop in the instruction stream 906 static RelocationHolder spec_for_immediate() { 907 const int oop_index = 0; 908 const int offset = 0; // if you want an offset, use the oop pool 909 RelocationHolder rh = newHolder(); 910 new(rh) oop_Relocation(oop_index, offset); 911 return rh; 912 } 913 914 private: 915 jint _oop_index; // if > 0, index into CodeBlob::oop_at 916 jint _offset; // byte offset to apply to the oop itself 917 918 oop_Relocation(int oop_index, int offset) { 919 _oop_index = oop_index; _offset = offset; 920 } 921 922 friend class RelocIterator; 923 oop_Relocation() { } 924 925 public: 926 int oop_index() { return _oop_index; } 927 int offset() { return _offset; } 928 929 // data is packed in "2_ints" format: [i o] or [Ii Oo] 930 void pack_data_to(CodeSection* dest); 931 void unpack_data(); 932 933 void fix_oop_relocation(); // reasserts oop value 934 935 address value() { return (address) *oop_addr(); } 936 937 bool oop_is_immediate() { return oop_index() == 0; } 938 939 oop* oop_addr(); // addr or &pool[jint_data] 940 oop oop_value(); // *oop_addr 941 // Note: oop_value transparently converts Universe::non_oop_word to NULL. 942}; 943 944class virtual_call_Relocation : public CallRelocation { 945 relocInfo::relocType type() { return relocInfo::virtual_call_type; } 946 947 public: 948 // "first_oop" points to the first associated set-oop. 949 // The oop_limit helps find the last associated set-oop. 950 // (See comments at the top of this file.) 951 static RelocationHolder spec(address first_oop, address oop_limit = NULL) { 952 RelocationHolder rh = newHolder(); 953 new(rh) virtual_call_Relocation(first_oop, oop_limit); 954 return rh; 955 } 956 957 virtual_call_Relocation(address first_oop, address oop_limit) { 958 _first_oop = first_oop; _oop_limit = oop_limit; 959 assert(first_oop != NULL, "first oop address must be specified"); 960 } 961 962 private: 963 address _first_oop; // location of first set-oop instruction 964 address _oop_limit; // search limit for set-oop instructions 965 966 friend class RelocIterator; 967 virtual_call_Relocation() { } 968 969 970 public: 971 address first_oop(); 972 address oop_limit(); 973 974 // data is packed as scaled offsets in "2_ints" format: [f l] or [Ff Ll] 975 // oop_limit is set to 0 if the limit falls somewhere within the call. 976 // When unpacking, a zero oop_limit is taken to refer to the end of the call. 977 // (This has the effect of bringing in the call's delay slot on SPARC.) 978 void pack_data_to(CodeSection* dest); 979 void unpack_data(); 980 981 void clear_inline_cache(); 982 983 // Figure out where an ic_call is hiding, given a set-oop or call. 984 // Either ic_call or first_oop must be non-null; the other is deduced. 985 // Code if non-NULL must be the CodeBlob, else it is deduced. 986 // The address of the patchable oop is also deduced. 987 // The returned iterator will enumerate over the oops and the ic_call, 988 // as well as any other relocations that happen to be in that span of code. 989 // Recognize relevant set_oops with: oop_reloc()->oop_addr() == oop_addr. 990 static RelocIterator parse_ic(CodeBlob* &code, address &ic_call, address &first_oop, oop* &oop_addr, bool *is_optimized); 991}; 992 993 994class opt_virtual_call_Relocation : public CallRelocation { 995 relocInfo::relocType type() { return relocInfo::opt_virtual_call_type; } 996 997 public: 998 static RelocationHolder spec() { 999 RelocationHolder rh = newHolder(); 1000 new(rh) opt_virtual_call_Relocation(); 1001 return rh; 1002 } 1003 1004 private: 1005 friend class RelocIterator; 1006 opt_virtual_call_Relocation() { } 1007 1008 public: 1009 void clear_inline_cache(); 1010 1011 // find the matching static_stub 1012 address static_stub(); 1013}; 1014 1015 1016class static_call_Relocation : public CallRelocation { 1017 relocInfo::relocType type() { return relocInfo::static_call_type; } 1018 1019 public: 1020 static RelocationHolder spec() { 1021 RelocationHolder rh = newHolder(); 1022 new(rh) static_call_Relocation(); 1023 return rh; 1024 } 1025 1026 private: 1027 friend class RelocIterator; 1028 static_call_Relocation() { } 1029 1030 public: 1031 void clear_inline_cache(); 1032 1033 // find the matching static_stub 1034 address static_stub(); 1035}; 1036 1037class static_stub_Relocation : public Relocation { 1038 relocInfo::relocType type() { return relocInfo::static_stub_type; } 1039 1040 public: 1041 static RelocationHolder spec(address static_call) { 1042 RelocationHolder rh = newHolder(); 1043 new(rh) static_stub_Relocation(static_call); 1044 return rh; 1045 } 1046 1047 private: 1048 address _static_call; // location of corresponding static_call 1049 1050 static_stub_Relocation(address static_call) { 1051 _static_call = static_call; 1052 } 1053 1054 friend class RelocIterator; 1055 static_stub_Relocation() { } 1056 1057 public: 1058 void clear_inline_cache(); 1059 1060 address static_call() { return _static_call; } 1061 1062 // data is packed as a scaled offset in "1_int" format: [c] or [Cc] 1063 void pack_data_to(CodeSection* dest); 1064 void unpack_data(); 1065}; 1066 1067class runtime_call_Relocation : public CallRelocation { 1068 relocInfo::relocType type() { return relocInfo::runtime_call_type; } 1069 1070 public: 1071 static RelocationHolder spec() { 1072 RelocationHolder rh = newHolder(); 1073 new(rh) runtime_call_Relocation(); 1074 return rh; 1075 } 1076 1077 private: 1078 friend class RelocIterator; 1079 runtime_call_Relocation() { } 1080 1081 public: 1082}; 1083 1084class external_word_Relocation : public DataRelocation { 1085 relocInfo::relocType type() { return relocInfo::external_word_type; } 1086 1087 public: 1088 static RelocationHolder spec(address target) { 1089 assert(target != NULL, "must not be null"); 1090 RelocationHolder rh = newHolder(); 1091 new(rh) external_word_Relocation(target); 1092 return rh; 1093 } 1094 1095 // Use this one where all 32/64 bits of the target live in the code stream. 1096 // The target must be an intptr_t, and must be absolute (not relative). 1097 static RelocationHolder spec_for_immediate() { 1098 RelocationHolder rh = newHolder(); 1099 new(rh) external_word_Relocation(NULL); 1100 return rh; 1101 } 1102 1103 private: 1104 address _target; // address in runtime 1105 1106 external_word_Relocation(address target) { 1107 _target = target; 1108 } 1109 1110 friend class RelocIterator; 1111 external_word_Relocation() { } 1112 1113 public: 1114 // data is packed as a well-known address in "1_int" format: [a] or [Aa] 1115 // The function runtime_address_to_index is used to turn full addresses 1116 // to short indexes, if they are pre-registered by the stub mechanism. 1117 // If the "a" value is 0 (i.e., _target is NULL), the address is stored 1118 // in the code stream. See external_word_Relocation::target(). 1119 void pack_data_to(CodeSection* dest); 1120 void unpack_data(); 1121 1122 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1123 address target(); // if _target==NULL, fetch addr from code stream 1124 address value() { return target(); } 1125}; 1126 1127class internal_word_Relocation : public DataRelocation { 1128 relocInfo::relocType type() { return relocInfo::internal_word_type; } 1129 1130 public: 1131 static RelocationHolder spec(address target) { 1132 assert(target != NULL, "must not be null"); 1133 RelocationHolder rh = newHolder(); 1134 new(rh) internal_word_Relocation(target); 1135 return rh; 1136 } 1137 1138 // use this one where all the bits of the target can fit in the code stream: 1139 static RelocationHolder spec_for_immediate() { 1140 RelocationHolder rh = newHolder(); 1141 new(rh) internal_word_Relocation(NULL); 1142 return rh; 1143 } 1144 1145 internal_word_Relocation(address target) { 1146 _target = target; 1147 _section = -1; // self-relative 1148 } 1149 1150 protected: 1151 address _target; // address in CodeBlob 1152 int _section; // section providing base address, if any 1153 1154 friend class RelocIterator; 1155 internal_word_Relocation() { } 1156 1157 // bit-width of LSB field in packed offset, if section >= 0 1158 enum { section_width = 2 }; // must equal CodeBuffer::sect_bits 1159 1160 public: 1161 // data is packed as a scaled offset in "1_int" format: [o] or [Oo] 1162 // If the "o" value is 0 (i.e., _target is NULL), the offset is stored 1163 // in the code stream. See internal_word_Relocation::target(). 1164 // If _section is not -1, it is appended to the low bits of the offset. 1165 void pack_data_to(CodeSection* dest); 1166 void unpack_data(); 1167 1168 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1169 address target(); // if _target==NULL, fetch addr from code stream 1170 int section() { return _section; } 1171 address value() { return target(); } 1172}; 1173 1174class section_word_Relocation : public internal_word_Relocation { 1175 relocInfo::relocType type() { return relocInfo::section_word_type; } 1176 1177 public: 1178 static RelocationHolder spec(address target, int section) { 1179 RelocationHolder rh = newHolder(); 1180 new(rh) section_word_Relocation(target, section); 1181 return rh; 1182 } 1183 1184 section_word_Relocation(address target, int section) { 1185 assert(target != NULL, "must not be null"); 1186 assert(section >= 0, "must be a valid section"); 1187 _target = target; 1188 _section = section; 1189 } 1190 1191 //void pack_data_to -- inherited 1192 void unpack_data(); 1193 1194 private: 1195 friend class RelocIterator; 1196 section_word_Relocation() { } 1197}; 1198 1199 1200class poll_Relocation : public Relocation { 1201 bool is_data() { return true; } 1202 relocInfo::relocType type() { return relocInfo::poll_type; } 1203 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1204}; 1205 1206class poll_return_Relocation : public Relocation { 1207 bool is_data() { return true; } 1208 relocInfo::relocType type() { return relocInfo::poll_return_type; } 1209 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest); 1210}; 1211 1212 1213class breakpoint_Relocation : public Relocation { 1214 relocInfo::relocType type() { return relocInfo::breakpoint_type; } 1215 1216 enum { 1217 // attributes which affect the interpretation of the data: 1218 removable_attr = 0x0010, // buffer [i...] allows for undoing the trap 1219 internal_attr = 0x0020, // the target is an internal addr (local stub) 1220 settable_attr = 0x0040, // the target is settable 1221 1222 // states which can change over time: 1223 enabled_state = 0x0100, // breakpoint must be active in running code 1224 active_state = 0x0200, // breakpoint instruction actually in code 1225 1226 kind_mask = 0x000F, // mask for extracting kind 1227 high_bit = 0x4000 // extra bit which is always set 1228 }; 1229 1230 public: 1231 enum { 1232 // kinds: 1233 initialization = 1, 1234 safepoint = 2 1235 }; 1236 1237 // If target is NULL, 32 bits are reserved for a later set_target(). 1238 static RelocationHolder spec(int kind, address target = NULL, bool internal_target = false) { 1239 RelocationHolder rh = newHolder(); 1240 new(rh) breakpoint_Relocation(kind, target, internal_target); 1241 return rh; 1242 } 1243 1244 private: 1245 // We require every bits value to NOT to fit into relocInfo::datalen_width, 1246 // because we are going to actually store state in the reloc, and so 1247 // cannot allow it to be compressed (and hence copied by the iterator). 1248 1249 short _bits; // bit-encoded kind, attrs, & state 1250 address _target; 1251 1252 breakpoint_Relocation(int kind, address target, bool internal_target); 1253 1254 friend class RelocIterator; 1255 breakpoint_Relocation() { } 1256 1257 short bits() const { return _bits; } 1258 short& live_bits() const { return data()[0]; } 1259 short* instrs() const { return data() + datalen() - instrlen(); } 1260 int instrlen() const { return removable() ? pd_breakpoint_size() : 0; } 1261 1262 void set_bits(short x) { 1263 assert(live_bits() == _bits, "must be the only mutator of reloc info"); 1264 live_bits() = _bits = x; 1265 } 1266 1267 public: 1268 address target() const; 1269 void set_target(address x); 1270 1271 int kind() const { return bits() & kind_mask; } 1272 bool enabled() const { return (bits() & enabled_state) != 0; } 1273 bool active() const { return (bits() & active_state) != 0; } 1274 bool internal() const { return (bits() & internal_attr) != 0; } 1275 bool removable() const { return (bits() & removable_attr) != 0; } 1276 bool settable() const { return (bits() & settable_attr) != 0; } 1277 1278 void set_enabled(bool b); // to activate, you must also say set_active 1279 void set_active(bool b); // actually inserts bpt (must be enabled 1st) 1280 1281 // data is packed as 16 bits, followed by the target (1 or 2 words), followed 1282 // if necessary by empty storage for saving away original instruction bytes. 1283 void pack_data_to(CodeSection* dest); 1284 void unpack_data(); 1285 1286 // during certain operations, breakpoints must be out of the way: 1287 void fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) { 1288 assert(!active(), "cannot perform relocation on enabled breakpoints"); 1289 } 1290}; 1291 1292 1293// We know all the xxx_Relocation classes, so now we can define these: 1294#define EACH_CASE(name) \ 1295inline name##_Relocation* RelocIterator::name##_reloc() { \ 1296 assert(type() == relocInfo::name##_type, "type must agree"); \ 1297 /* The purpose of the placed "new" is to re-use the same */ \ 1298 /* stack storage for each new iteration. */ \ 1299 name##_Relocation* r = new(_rh) name##_Relocation(); \ 1300 r->set_binding(this); \ 1301 r->name##_Relocation::unpack_data(); \ 1302 return r; \ 1303} 1304APPLY_TO_RELOCATIONS(EACH_CASE); 1305#undef EACH_CASE 1306 1307inline RelocIterator::RelocIterator(CodeBlob* cb, address begin, address limit) { 1308 initialize(cb, begin, limit); 1309} 1310 1311// if you are going to patch code, you should use this subclass of 1312// RelocIterator 1313class PatchingRelocIterator : public RelocIterator { 1314 private: 1315 RelocIterator _init_state; 1316 1317 void prepass(); // deactivates all breakpoints 1318 void postpass(); // reactivates all enabled breakpoints 1319 1320 // do not copy these puppies; it would have unpredictable side effects 1321 // these are private and have no bodies defined because they should not be called 1322 PatchingRelocIterator(const RelocIterator&); 1323 void operator=(const RelocIterator&); 1324 1325 public: 1326 PatchingRelocIterator(CodeBlob* cb, address begin =NULL, address limit =NULL) 1327 : RelocIterator(cb, begin, limit) { prepass(); } 1328 1329 ~PatchingRelocIterator() { postpass(); } 1330}; 1331