gold/reloc.h

   1 // reloc.h -- relocate input files for gold   -*- C++ -*-
   2
   3 // Copyright (C) 2006-2015 Free Software Foundation, Inc.
   4 // Written by Ian Lance Taylor <iant@google.com>.
   5
   6 // This file is part of gold.
   7
   8 // This program is free software; you can redistribute it and/or modify
   9 // it under the terms of the GNU General Public License as published by
  10 // the Free Software Foundation; either version 3 of the License, or
  11 // (at your option) any later version.
  12
  13 // This program is distributed in the hope that it will be useful,
  14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 // GNU General Public License for more details.
  17
  18 // You should have received a copy of the GNU General Public License
  19 // along with this program; if not, write to the Free Software
  20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  21 // MA 02110-1301, USA.
  22
  23 #ifndef GOLD_RELOC_H
  24 #define GOLD_RELOC_H
  25
  26 #include <vector>
  27 #ifdef HAVE_BYTESWAP_H
  28 #include <byteswap.h>
  29 #endif
  30
  31 #include "elfcpp.h"
  32 #include "workqueue.h"
  33
  34 namespace gold
  35 {
  36
  37 class General_options;
  38 class Object;
  39 class Relobj;
  40 struct Read_relocs_data;
  41 class Symbol;
  42 class Layout;
  43 class Output_data;
  44 class Output_section;
  45
  46 template<int size>
  47 class Sized_symbol;
  48
  49 template<int size, bool big_endian>
  50 class Sized_relobj_file;
  51
  52 template<int size>
  53 class Symbol_value;
  54
  55 template<int sh_type, bool dynamic, int size, bool big_endian>
  56 class Output_data_reloc;
  57
  58 // A class to read the relocations for an object file, and then queue
  59 // up a task to see if they require any GOT/PLT/COPY relocations in
  60 // the symbol table.
  61
  62 class Read_relocs : public Task
  63 {
  64  public:
  65   //   THIS_BLOCKER and NEXT_BLOCKER are passed along to a Scan_relocs
  66   // or Gc_process_relocs task, so that they run in a deterministic
  67   // order.
  68   Read_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
  69               Task_token* this_blocker, Task_token* next_blocker)
  70     : symtab_(symtab), layout_(layout), object_(object),
  71       this_blocker_(this_blocker), next_blocker_(next_blocker)
  72   { }
  73
  74   // The standard Task methods.
  75
  76   Task_token*
  77   is_runnable();
  78
  79   void
  80   locks(Task_locker*);
  81
  82   void
  83   run(Workqueue*);
  84
  85   std::string
  86   get_name() const;
  87
  88  private:
  89   Symbol_table* symtab_;
  90   Layout* layout_;
  91   Relobj* object_;
  92   Task_token* this_blocker_;
  93   Task_token* next_blocker_;
  94 };
  95
  96 // Process the relocs to figure out which sections are garbage.
  97 // Very similar to scan relocs.
  98
  99 class Gc_process_relocs : public Task
 100 {
 101  public:
 102   // THIS_BLOCKER prevents this task from running until the previous
 103   // one is finished.  NEXT_BLOCKER prevents the next task from
 104   // running.
 105   Gc_process_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
 106                     Read_relocs_data* rd, Task_token* this_blocker,
 107                     Task_token* next_blocker)
 108     : symtab_(symtab), layout_(layout), object_(object), rd_(rd),
 109       this_blocker_(this_blocker), next_blocker_(next_blocker)
 110   { }
 111
 112   ~Gc_process_relocs();
 113
 114   // The standard Task methods.
 115
 116   Task_token*
 117   is_runnable();
 118
 119   void
 120   locks(Task_locker*);
 121
 122   void
 123   run(Workqueue*);
 124
 125   std::string
 126   get_name() const;
 127
 128  private:
 129   Symbol_table* symtab_;
 130   Layout* layout_;
 131   Relobj* object_;
 132   Read_relocs_data* rd_;
 133   Task_token* this_blocker_;
 134   Task_token* next_blocker_;
 135 };
 136
 137 // Scan the relocations for an object to see if they require any
 138 // GOT/PLT/COPY relocations.
 139
 140 class Scan_relocs : public Task
 141 {
 142  public:
 143   // THIS_BLOCKER prevents this task from running until the previous
 144   // one is finished.  NEXT_BLOCKER prevents the next task from
 145   // running.
 146   Scan_relocs(Symbol_table* symtab, Layout* layout, Relobj* object,
 147               Read_relocs_data* rd, Task_token* this_blocker,
 148               Task_token* next_blocker)
 149     : symtab_(symtab), layout_(layout), object_(object), rd_(rd),
 150       this_blocker_(this_blocker), next_blocker_(next_blocker)
 151   { }
 152
 153   ~Scan_relocs();
 154
 155   // The standard Task methods.
 156
 157   Task_token*
 158   is_runnable();
 159
 160   void
 161   locks(Task_locker*);
 162
 163   void
 164   run(Workqueue*);
 165
 166   std::string
 167   get_name() const;
 168
 169  private:
 170   Symbol_table* symtab_;
 171   Layout* layout_;
 172   Relobj* object_;
 173   Read_relocs_data* rd_;
 174   Task_token* this_blocker_;
 175   Task_token* next_blocker_;
 176 };
 177
 178 // A class to perform all the relocations for an object file.
 179
 180 class Relocate_task : public Task
 181 {
 182  public:
 183   Relocate_task(const Symbol_table* symtab, const Layout* layout,
 184                 Relobj* object, Output_file* of,
 185                 Task_token* input_sections_blocker,
 186                 Task_token* output_sections_blocker, Task_token* final_blocker)
 187     : symtab_(symtab), layout_(layout), object_(object), of_(of),
 188       input_sections_blocker_(input_sections_blocker),
 189       output_sections_blocker_(output_sections_blocker),
 190       final_blocker_(final_blocker)
 191   { }
 192
 193   // The standard Task methods.
 194
 195   Task_token*
 196   is_runnable();
 197
 198   void
 199   locks(Task_locker*);
 200
 201   void
 202   run(Workqueue*);
 203
 204   std::string
 205   get_name() const;
 206
 207  private:
 208   const Symbol_table* symtab_;
 209   const Layout* layout_;
 210   Relobj* object_;
 211   Output_file* of_;
 212   Task_token* input_sections_blocker_;
 213   Task_token* output_sections_blocker_;
 214   Task_token* final_blocker_;
 215 };
 216
 217 // During a relocatable link, this class records how relocations
 218 // should be handled for a single input reloc section.  An instance of
 219 // this class is created while scanning relocs, and it is used while
 220 // processing relocs.
 221
 222 class Relocatable_relocs
 223 {
 224  public:
 225   // We use a vector of unsigned char to indicate how the input relocs
 226   // should be handled.  Each element is one of the following values.
 227   // We create this vector when we initially scan the relocations.
 228   enum Reloc_strategy
 229   {
 230     // Copy the input reloc.  Don't modify it other than updating the
 231     // r_offset field and the r_sym part of the r_info field.
 232     RELOC_COPY,
 233     // Copy the input reloc which is against an STT_SECTION symbol.
 234     // Update the r_offset and r_sym part of the r_info field.  Adjust
 235     // the addend by subtracting the value of the old local symbol and
 236     // adding the value of the new local symbol.  The addend is in the
 237     // SHT_RELA reloc and the contents of the data section do not need
 238     // to be changed.
 239     RELOC_ADJUST_FOR_SECTION_RELA,
 240     // Like RELOC_ADJUST_FOR_SECTION_RELA but the addend should not be
 241     // adjusted.
 242     RELOC_ADJUST_FOR_SECTION_0,
 243     // Like RELOC_ADJUST_FOR_SECTION_RELA but the contents of the
 244     // section need to be changed.  The number indicates the number of
 245     // bytes in the addend in the section contents.
 246     RELOC_ADJUST_FOR_SECTION_1,
 247     RELOC_ADJUST_FOR_SECTION_2,
 248     RELOC_ADJUST_FOR_SECTION_4,
 249     RELOC_ADJUST_FOR_SECTION_8,
 250     // Like RELOC_ADJUST_FOR_SECTION_4 but for unaligned relocs.
 251     RELOC_ADJUST_FOR_SECTION_4_UNALIGNED,
 252     // Discard the input reloc--process it completely when relocating
 253     // the data section contents.
 254     RELOC_DISCARD,
 255     // An input reloc which is not discarded, but which requires
 256     // target specific processing in order to update it.
 257     RELOC_SPECIAL
 258   };
 259
 260   Relocatable_relocs()
 261     : reloc_strategies_(), output_reloc_count_(0), posd_(NULL)
 262   { }
 263
 264   // Record the number of relocs.
 265   void
 266   set_reloc_count(size_t reloc_count)
 267   { this->reloc_strategies_.reserve(reloc_count); }
 268
 269   // Record what to do for the next reloc.
 270   void
 271   set_next_reloc_strategy(Reloc_strategy strategy)
 272   {
 273     this->reloc_strategies_.push_back(static_cast<unsigned char>(strategy));
 274     if (strategy != RELOC_DISCARD)
 275       ++this->output_reloc_count_;
 276   }
 277
 278   // Record the Output_data associated with this reloc section.
 279   void
 280   set_output_data(Output_data* posd)
 281   {
 282     gold_assert(this->posd_ == NULL);
 283     this->posd_ = posd;
 284   }
 285
 286   // Return the Output_data associated with this reloc section.
 287   Output_data*
 288   output_data() const
 289   { return this->posd_; }
 290
 291   // Return what to do for reloc I.
 292   Reloc_strategy
 293   strategy(unsigned int i) const
 294   {
 295     gold_assert(i < this->reloc_strategies_.size());
 296     return static_cast<Reloc_strategy>(this->reloc_strategies_[i]);
 297   }
 298
 299   // Return the number of relocations to create in the output file.
 300   size_t
 301   output_reloc_count() const
 302   { return this->output_reloc_count_; }
 303
 304  private:
 305   typedef std::vector<unsigned char> Reloc_strategies;
 306
 307   // The strategies for the input reloc.  There is one entry in this
 308   // vector for each relocation in the input section.
 309   Reloc_strategies reloc_strategies_;
 310   // The number of relocations to be created in the output file.
 311   size_t output_reloc_count_;
 312   // The output data structure associated with this relocation.
 313   Output_data* posd_;
 314 };
 315
 316 // Standard relocation routines which are used on many targets.  Here
 317 // SIZE and BIG_ENDIAN refer to the target, not the relocation type.
 318
 319 template<int size, bool big_endian>
 320 class Relocate_functions
 321 {
 322 private:
 323   // Do a simple relocation with the addend in the section contents.
 324   // VALSIZE is the size of the value.
 325   template<int valsize>
 326   static inline void
 327   rel(unsigned char* view,
 328       typename elfcpp::Swap<valsize, big_endian>::Valtype value)
 329   {
 330     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 331     Valtype* wv = reinterpret_cast<Valtype*>(view);
 332     Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
 333     elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value);
 334   }
 335
 336   // Like the above but for relocs at unaligned addresses.
 337   template<int valsize>
 338   static inline void
 339   rel_unaligned(unsigned char* view,
 340                 typename elfcpp::Swap<valsize, big_endian>::Valtype value)
 341   {
 342     typedef typename elfcpp::Swap_unaligned<valsize, big_endian>::Valtype
 343         Valtype;
 344     Valtype x = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
 345     elfcpp::Swap_unaligned<valsize, big_endian>::writeval(view, x + value);
 346   }
 347
 348   // Do a simple relocation using a Symbol_value with the addend in
 349   // the section contents.  VALSIZE is the size of the value to
 350   // relocate.
 351   template<int valsize>
 352   static inline void
 353   rel(unsigned char* view,
 354       const Sized_relobj_file<size, big_endian>* object,
 355       const Symbol_value<size>* psymval)
 356   {
 357     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 358     Valtype* wv = reinterpret_cast<Valtype*>(view);
 359     Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
 360     x = psymval->value(object, x);
 361     elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
 362   }
 363
 364   // Like the above but for relocs at unaligned addresses.
 365   template<int valsize>
 366   static inline void
 367   rel_unaligned(unsigned char* view,
 368                 const Sized_relobj_file<size, big_endian>* object,
 369                 const Symbol_value<size>* psymval)
 370   {
 371     typedef typename elfcpp::Swap_unaligned<valsize, big_endian>::Valtype
 372         Valtype;
 373     Valtype x = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
 374     x = psymval->value(object, x);
 375     elfcpp::Swap_unaligned<valsize, big_endian>::writeval(view, x);
 376   }
 377
 378   // Do a simple relocation with the addend in the relocation.
 379   // VALSIZE is the size of the value.
 380   template<int valsize>
 381   static inline void
 382   rela(unsigned char* view,
 383        typename elfcpp::Swap<valsize, big_endian>::Valtype value,
 384        typename elfcpp::Swap<valsize, big_endian>::Valtype addend)
 385   {
 386     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 387     Valtype* wv = reinterpret_cast<Valtype*>(view);
 388     elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend);
 389   }
 390
 391   // Do a simple relocation using a symbol value with the addend in
 392   // the relocation.  VALSIZE is the size of the value.
 393   template<int valsize>
 394   static inline void
 395   rela(unsigned char* view,
 396        const Sized_relobj_file<size, big_endian>* object,
 397        const Symbol_value<size>* psymval,
 398        typename elfcpp::Swap<valsize, big_endian>::Valtype addend)
 399   {
 400     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 401     Valtype* wv = reinterpret_cast<Valtype*>(view);
 402     Valtype x = psymval->value(object, addend);
 403     elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
 404   }
 405
 406   // Do a simple PC relative relocation with the addend in the section
 407   // contents.  VALSIZE is the size of the value.
 408   template<int valsize>
 409   static inline void
 410   pcrel(unsigned char* view,
 411         typename elfcpp::Swap<valsize, big_endian>::Valtype value,
 412         typename elfcpp::Elf_types<size>::Elf_Addr address)
 413   {
 414     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 415     Valtype* wv = reinterpret_cast<Valtype*>(view);
 416     Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
 417     elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address);
 418   }
 419
 420   // Like the above but for relocs at unaligned addresses.
 421   template<int valsize>
 422   static inline void
 423   pcrel_unaligned(unsigned char* view,
 424                   typename elfcpp::Swap<valsize, big_endian>::Valtype value,
 425                   typename elfcpp::Elf_types<size>::Elf_Addr address)
 426   {
 427     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 428     Valtype x = elfcpp::Swap_unaligned<valsize, big_endian>::readval(view);
 429     elfcpp::Swap_unaligned<valsize, big_endian>::writeval(view,
 430                                                           x + value - address);
 431   }
 432
 433   // Do a simple PC relative relocation with a Symbol_value with the
 434   // addend in the section contents.  VALSIZE is the size of the
 435   // value.
 436   template<int valsize>
 437   static inline void
 438   pcrel(unsigned char* view,
 439         const Sized_relobj_file<size, big_endian>* object,
 440         const Symbol_value<size>* psymval,
 441         typename elfcpp::Elf_types<size>::Elf_Addr address)
 442   {
 443     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 444     Valtype* wv = reinterpret_cast<Valtype*>(view);
 445     Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
 446     x = psymval->value(object, x);
 447     elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
 448   }
 449
 450   // Do a simple PC relative relocation with the addend in the
 451   // relocation.  VALSIZE is the size of the value.
 452   template<int valsize>
 453   static inline void
 454   pcrela(unsigned char* view,
 455          typename elfcpp::Swap<valsize, big_endian>::Valtype value,
 456          typename elfcpp::Swap<valsize, big_endian>::Valtype addend,
 457          typename elfcpp::Elf_types<size>::Elf_Addr address)
 458   {
 459     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 460     Valtype* wv = reinterpret_cast<Valtype*>(view);
 461     elfcpp::Swap<valsize, big_endian>::writeval(wv, value + addend - address);
 462   }
 463
 464   // Do a simple PC relative relocation with a Symbol_value with the
 465   // addend in the relocation.  VALSIZE is the size of the value.
 466   template<int valsize>
 467   static inline void
 468   pcrela(unsigned char* view,
 469          const Sized_relobj_file<size, big_endian>* object,
 470          const Symbol_value<size>* psymval,
 471          typename elfcpp::Swap<valsize, big_endian>::Valtype addend,
 472          typename elfcpp::Elf_types<size>::Elf_Addr address)
 473   {
 474     typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
 475     Valtype* wv = reinterpret_cast<Valtype*>(view);
 476     Valtype x = psymval->value(object, addend);
 477     elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
 478   }
 479
 480   typedef Relocate_functions<size, big_endian> This;
 481
 482 public:
 483   // Do a simple 8-bit REL relocation with the addend in the section
 484   // contents.
 485   static inline void
 486   rel8(unsigned char* view, unsigned char value)
 487   { This::template rel<8>(view, value); }
 488
 489   static inline void
 490   rel8(unsigned char* view,
 491        const Sized_relobj_file<size, big_endian>* object,
 492        const Symbol_value<size>* psymval)
 493   { This::template rel<8>(view, object, psymval); }
 494
 495   // Do an 8-bit RELA relocation with the addend in the relocation.
 496   static inline void
 497   rela8(unsigned char* view, unsigned char value, unsigned char addend)
 498   { This::template rela<8>(view, value, addend); }
 499
 500   static inline void
 501   rela8(unsigned char* view,
 502         const Sized_relobj_file<size, big_endian>* object,
 503         const Symbol_value<size>* psymval,
 504         unsigned char addend)
 505   { This::template rela<8>(view, object, psymval, addend); }
 506
 507   // Do a simple 8-bit PC relative relocation with the addend in the
 508   // section contents.
 509   static inline void
 510   pcrel8(unsigned char* view, unsigned char value,
 511          typename elfcpp::Elf_types<size>::Elf_Addr address)
 512   { This::template pcrel<8>(view, value, address); }
 513
 514   static inline void
 515   pcrel8(unsigned char* view,
 516          const Sized_relobj_file<size, big_endian>* object,
 517          const Symbol_value<size>* psymval,
 518          typename elfcpp::Elf_types<size>::Elf_Addr address)
 519   { This::template pcrel<8>(view, object, psymval, address); }
 520
 521   // Do a simple 8-bit PC relative RELA relocation with the addend in
 522   // the reloc.
 523   static inline void
 524   pcrela8(unsigned char* view, unsigned char value, unsigned char addend,
 525           typename elfcpp::Elf_types<size>::Elf_Addr address)
 526   { This::template pcrela<8>(view, value, addend, address); }
 527
 528   static inline void
 529   pcrela8(unsigned char* view,
 530           const Sized_relobj_file<size, big_endian>* object,
 531           const Symbol_value<size>* psymval,
 532           unsigned char addend,
 533           typename elfcpp::Elf_types<size>::Elf_Addr address)
 534   { This::template pcrela<8>(view, object, psymval, addend, address); }
 535
 536   // Do a simple 16-bit REL relocation with the addend in the section
 537   // contents.
 538   static inline void
 539   rel16(unsigned char* view, elfcpp::Elf_Half value)
 540   { This::template rel<16>(view, value); }
 541
 542   static inline void
 543   rel16(unsigned char* view,
 544         const Sized_relobj_file<size, big_endian>* object,
 545         const Symbol_value<size>* psymval)
 546   { This::template rel<16>(view, object, psymval); }
 547
 548   // Do an 16-bit RELA relocation with the addend in the relocation.
 549   static inline void
 550   rela16(unsigned char* view, elfcpp::Elf_Half value, elfcpp::Elf_Half addend)
 551   { This::template rela<16>(view, value, addend); }
 552
 553   static inline void
 554   rela16(unsigned char* view,
 555          const Sized_relobj_file<size, big_endian>* object,
 556          const Symbol_value<size>* psymval,
 557          elfcpp::Elf_Half addend)
 558   { This::template rela<16>(view, object, psymval, addend); }
 559
 560   // Do a simple 16-bit PC relative REL relocation with the addend in
 561   // the section contents.
 562   static inline void
 563   pcrel16(unsigned char* view, elfcpp::Elf_Half value,
 564           typename elfcpp::Elf_types<size>::Elf_Addr address)
 565   { This::template pcrel<16>(view, value, address); }
 566
 567   static inline void
 568   pcrel16(unsigned char* view,
 569           const Sized_relobj_file<size, big_endian>* object,
 570           const Symbol_value<size>* psymval,
 571           typename elfcpp::Elf_types<size>::Elf_Addr address)
 572   { This::template pcrel<16>(view, object, psymval, address); }
 573
 574   // Do a simple 16-bit PC relative RELA relocation with the addend in
 575   // the reloc.
 576   static inline void
 577   pcrela16(unsigned char* view, elfcpp::Elf_Half value,
 578            elfcpp::Elf_Half addend,
 579            typename elfcpp::Elf_types<size>::Elf_Addr address)
 580   { This::template pcrela<16>(view, value, addend, address); }
 581
 582   static inline void
 583   pcrela16(unsigned char* view,
 584            const Sized_relobj_file<size, big_endian>* object,
 585            const Symbol_value<size>* psymval,
 586            elfcpp::Elf_Half addend,
 587            typename elfcpp::Elf_types<size>::Elf_Addr address)
 588   { This::template pcrela<16>(view, object, psymval, addend, address); }
 589
 590   // Do a simple 32-bit REL relocation with the addend in the section
 591   // contents.
 592   static inline void
 593   rel32(unsigned char* view, elfcpp::Elf_Word value)
 594   { This::template rel<32>(view, value); }
 595
 596   // Like above but for relocs at unaligned addresses.
 597   static inline void
 598   rel32_unaligned(unsigned char* view, elfcpp::Elf_Word value)
 599   { This::template rel_unaligned<32>(view, value); }
 600
 601   static inline void
 602   rel32(unsigned char* view,
 603         const Sized_relobj_file<size, big_endian>* object,
 604         const Symbol_value<size>* psymval)
 605   { This::template rel<32>(view, object, psymval); }
 606
 607   // Like above but for relocs at unaligned addresses.
 608   static inline void
 609   rel32_unaligned(unsigned char* view,
 610                   const Sized_relobj_file<size, big_endian>* object,
 611                   const Symbol_value<size>* psymval)
 612   { This::template rel_unaligned<32>(view, object, psymval); }
 613
 614   // Do an 32-bit RELA relocation with the addend in the relocation.
 615   static inline void
 616   rela32(unsigned char* view, elfcpp::Elf_Word value, elfcpp::Elf_Word addend)
 617   { This::template rela<32>(view, value, addend); }
 618
 619   static inline void
 620   rela32(unsigned char* view,
 621          const Sized_relobj_file<size, big_endian>* object,
 622          const Symbol_value<size>* psymval,
 623          elfcpp::Elf_Word addend)
 624   { This::template rela<32>(view, object, psymval, addend); }
 625
 626   // Do a simple 32-bit PC relative REL relocation with the addend in
 627   // the section contents.
 628   static inline void
 629   pcrel32(unsigned char* view, elfcpp::Elf_Word value,
 630           typename elfcpp::Elf_types<size>::Elf_Addr address)
 631   { This::template pcrel<32>(view, value, address); }
 632
 633   // Unaligned version of the above.
 634   static inline void
 635   pcrel32_unaligned(unsigned char* view, elfcpp::Elf_Word value,
 636                     typename elfcpp::Elf_types<size>::Elf_Addr address)
 637   { This::template pcrel_unaligned<32>(view, value, address); }
 638
 639   static inline void
 640   pcrel32(unsigned char* view,
 641           const Sized_relobj_file<size, big_endian>* object,
 642           const Symbol_value<size>* psymval,
 643           typename elfcpp::Elf_types<size>::Elf_Addr address)
 644   { This::template pcrel<32>(view, object, psymval, address); }
 645
 646   // Do a simple 32-bit PC relative RELA relocation with the addend in
 647   // the relocation.
 648   static inline void
 649   pcrela32(unsigned char* view, elfcpp::Elf_Word value,
 650            elfcpp::Elf_Word addend,
 651            typename elfcpp::Elf_types<size>::Elf_Addr address)
 652   { This::template pcrela<32>(view, value, addend, address); }
 653
 654   static inline void
 655   pcrela32(unsigned char* view,
 656            const Sized_relobj_file<size, big_endian>* object,
 657            const Symbol_value<size>* psymval,
 658            elfcpp::Elf_Word addend,
 659            typename elfcpp::Elf_types<size>::Elf_Addr address)
 660   { This::template pcrela<32>(view, object, psymval, addend, address); }
 661
 662   // Do a simple 64-bit REL relocation with the addend in the section
 663   // contents.
 664   static inline void
 665   rel64(unsigned char* view, elfcpp::Elf_Xword value)
 666   { This::template rel<64>(view, value); }
 667
 668   static inline void
 669   rel64(unsigned char* view,
 670         const Sized_relobj_file<size, big_endian>* object,
 671         const Symbol_value<size>* psymval)
 672   { This::template rel<64>(view, object, psymval); }
 673
 674   // Do a 64-bit RELA relocation with the addend in the relocation.
 675   static inline void
 676   rela64(unsigned char* view, elfcpp::Elf_Xword value,
 677          elfcpp::Elf_Xword addend)
 678   { This::template rela<64>(view, value, addend); }
 679
 680   static inline void
 681   rela64(unsigned char* view,
 682          const Sized_relobj_file<size, big_endian>* object,
 683          const Symbol_value<size>* psymval,
 684          elfcpp::Elf_Xword addend)
 685   { This::template rela<64>(view, object, psymval, addend); }
 686
 687   // Do a simple 64-bit PC relative REL relocation with the addend in
 688   // the section contents.
 689   static inline void
 690   pcrel64(unsigned char* view, elfcpp::Elf_Xword value,
 691           typename elfcpp::Elf_types<size>::Elf_Addr address)
 692   { This::template pcrel<64>(view, value, address); }
 693
 694   static inline void
 695   pcrel64(unsigned char* view,
 696           const Sized_relobj_file<size, big_endian>* object,
 697           const Symbol_value<size>* psymval,
 698           typename elfcpp::Elf_types<size>::Elf_Addr address)
 699   { This::template pcrel<64>(view, object, psymval, address); }
 700
 701   // Do a simple 64-bit PC relative RELA relocation with the addend in
 702   // the relocation.
 703   static inline void
 704   pcrela64(unsigned char* view, elfcpp::Elf_Xword value,
 705            elfcpp::Elf_Xword addend,
 706            typename elfcpp::Elf_types<size>::Elf_Addr address)
 707   { This::template pcrela<64>(view, value, addend, address); }
 708
 709   static inline void
 710   pcrela64(unsigned char* view,
 711            const Sized_relobj_file<size, big_endian>* object,
 712            const Symbol_value<size>* psymval,
 713            elfcpp::Elf_Xword addend,
 714            typename elfcpp::Elf_types<size>::Elf_Addr address)
 715   { This::template pcrela<64>(view, object, psymval, addend, address); }
 716 };
 717
 718 // Integer manipulation functions used by various targets when
 719 // performing relocations.
 720
 721 template<int bits>
 722 class Bits
 723 {
 724  public:
 725   // Sign extend an n-bit unsigned integer stored in a uint32_t into
 726   // an int32_t.  BITS must be between 1 and 32.
 727   static inline int32_t
 728   sign_extend32(uint32_t val)
 729   {
 730     gold_assert(bits > 0 && bits <= 32);
 731     if (bits == 32)
 732       return static_cast<int32_t>(val);
 733     uint32_t mask = (~static_cast<uint32_t>(0)) >> (32 - bits);
 734     val &= mask;
 735     uint32_t top_bit = 1U << (bits - 1);
 736     int32_t as_signed = static_cast<int32_t>(val);
 737     if ((val & top_bit) != 0)
 738       as_signed -= static_cast<int32_t>(top_bit * 2);
 739     return as_signed;
 740   }
 741
 742   // Return true if VAL (stored in a uint32_t) has overflowed a signed
 743   // value with BITS bits.
 744   static inline bool
 745   has_overflow32(uint32_t val)
 746   {
 747     gold_assert(bits > 0 && bits <= 32);
 748     if (bits == 32)
 749       return false;
 750     int32_t max = (1 << (bits - 1)) - 1;
 751     int32_t min = -(1 << (bits - 1));
 752     int32_t as_signed = static_cast<int32_t>(val);
 753     return as_signed > max || as_signed < min;
 754   }
 755
 756   // Return true if VAL (stored in a uint32_t) has overflowed both a
 757   // signed and an unsigned value.  E.g.,
 758   // Bits<8>::has_signed_unsigned_overflow32 would check -128 <= VAL <
 759   // 255.
 760   static inline bool
 761   has_signed_unsigned_overflow32(uint32_t val)
 762   {
 763     gold_assert(bits > 0 && bits <= 32);
 764     if (bits == 32)
 765       return false;
 766     int32_t max = static_cast<int32_t>((1U << bits) - 1);
 767     int32_t min = -(1 << (bits - 1));
 768     int32_t as_signed = static_cast<int32_t>(val);
 769     return as_signed > max || as_signed < min;
 770   }
 771
 772   // Select bits from A and B using bits in MASK.  For each n in
 773   // [0..31], the n-th bit in the result is chosen from the n-th bits
 774   // of A and B.  A zero selects A and a one selects B.
 775   static inline uint32_t
 776   bit_select32(uint32_t a, uint32_t b, uint32_t mask)
 777   { return (a & ~mask) | (b & mask); }
 778
 779   // Sign extend an n-bit unsigned integer stored in a uint64_t into
 780   // an int64_t.  BITS must be between 1 and 64.
 781   static inline int64_t
 782   sign_extend(uint64_t val)
 783   {
 784     gold_assert(bits > 0 && bits <= 64);
 785     if (bits == 64)
 786       return static_cast<int64_t>(val);
 787     uint64_t mask = (~static_cast<uint64_t>(0)) >> (64 - bits);
 788     val &= mask;
 789     uint64_t top_bit = static_cast<uint64_t>(1) << (bits - 1);
 790     int64_t as_signed = static_cast<int64_t>(val);
 791     if ((val & top_bit) != 0)
 792       as_signed -= static_cast<int64_t>(top_bit * 2);
 793     return as_signed;
 794   }
 795
 796   // Return true if VAL (stored in a uint64_t) has overflowed a signed
 797   // value with BITS bits.
 798   static inline bool
 799   has_overflow(uint64_t val)
 800   {
 801     gold_assert(bits > 0 && bits <= 64);
 802     if (bits == 64)
 803       return false;
 804     int64_t max = (static_cast<int64_t>(1) << (bits - 1)) - 1;
 805     int64_t min = -(static_cast<int64_t>(1) << (bits - 1));
 806     int64_t as_signed = static_cast<int64_t>(val);
 807     return as_signed > max || as_signed < min;
 808   }
 809
 810   // Return true if VAL (stored in a uint64_t) has overflowed both a
 811   // signed and an unsigned value.  E.g.,
 812   // Bits<8>::has_signed_unsigned_overflow would check -128 <= VAL <
 813   // 255.
 814   static inline bool
 815   has_signed_unsigned_overflow64(uint64_t val)
 816   {
 817     gold_assert(bits > 0 && bits <= 64);
 818     if (bits == 64)
 819       return false;
 820     int64_t max = static_cast<int64_t>((static_cast<uint64_t>(1) << bits) - 1);
 821     int64_t min = -(static_cast<int64_t>(1) << (bits - 1));
 822     int64_t as_signed = static_cast<int64_t>(val);
 823     return as_signed > max || as_signed < min;
 824   }
 825
 826   // Select bits from A and B using bits in MASK.  For each n in
 827   // [0..31], the n-th bit in the result is chosen from the n-th bits
 828   // of A and B.  A zero selects A and a one selects B.
 829   static inline uint64_t
 830   bit_select64(uint64_t a, uint64_t b, uint64_t mask)
 831   { return (a & ~mask) | (b & mask); }
 832 };
 833
 834 // Track relocations while reading a section.  This lets you ask for
 835 // the relocation at a certain offset, and see how relocs occur
 836 // between points of interest.
 837
 838 template<int size, bool big_endian>
 839 class Track_relocs
 840 {
 841  public:
 842   Track_relocs()
 843     : prelocs_(NULL), len_(0), pos_(0), reloc_size_(0)
 844   { }
 845
 846   // Initialize the Track_relocs object.  OBJECT is the object holding
 847   // the reloc section, RELOC_SHNDX is the section index of the reloc
 848   // section, and RELOC_TYPE is the type of the reloc section
 849   // (elfcpp::SHT_REL or elfcpp::SHT_RELA).  This returns false if
 850   // something went wrong.
 851   bool
 852   initialize(Object* object, unsigned int reloc_shndx,
 853              unsigned int reloc_type);
 854
 855   // Return the offset in the data section to which the next reloc
 856   // applies.  This returns -1 if there is no next reloc.
 857   off_t
 858   next_offset() const;
 859
 860   // Return the symbol index of the next reloc.  This returns -1U if
 861   // there is no next reloc.
 862   unsigned int
 863   next_symndx() const;
 864
 865   // Return the addend of the next reloc.  This returns 0 if there is
 866   // no next reloc.
 867   uint64_t
 868   next_addend() const;
 869
 870   // Advance to OFFSET within the data section, and return the number
 871   // of relocs which would be skipped.
 872   int
 873   advance(off_t offset);
 874
 875   // Checkpoint the current position in the reloc section.
 876   section_size_type
 877   checkpoint() const
 878   { return this->pos_; }
 879
 880   // Reset the position to CHECKPOINT.
 881   void
 882   reset(section_size_type checkpoint)
 883   { this->pos_ = checkpoint; }
 884
 885  private:
 886   // The contents of the input object's reloc section.
 887   const unsigned char* prelocs_;
 888   // The length of the reloc section.
 889   section_size_type len_;
 890   // Our current position in the reloc section.
 891   section_size_type pos_;
 892   // The size of the relocs in the section.
 893   int reloc_size_;
 894 };
 895
 896 } // End namespace gold.
 897
 898 #endif // !defined(GOLD_RELOC_H)