gdb/regcache.h

   1 /* Cache and manage the values of registers for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef REGCACHE_H
  21 #define REGCACHE_H
  22
  23 #include "gdbsupport/array-view.h"
  24 #include "gdbsupport/common-regcache.h"
  25 #include "gdbsupport/function-view.h"
  26 #include "gdbsupport/traits.h"
  27
  28 struct regcache;
  29 struct regset;
  30 struct gdbarch;
  31 class thread_info;
  32 struct process_stratum_target;
  33 struct inferior;
  34
  35 extern struct regcache *get_thread_regcache (process_stratum_target *target,
  36                                              ptid_t ptid);
  37
  38 /* Get the regcache of THREAD.  */
  39 extern struct regcache *get_thread_regcache (thread_info *thread);
  40
  41 extern regcache *get_thread_arch_regcache (inferior *inf_for_target_calls,
  42                                            ptid_t ptid, gdbarch *arch);
  43
  44 extern enum register_status
  45   regcache_raw_read_signed (struct regcache *regcache,
  46                             int regnum, LONGEST *val);
  47
  48 extern void regcache_raw_write_signed (struct regcache *regcache,
  49                                        int regnum, LONGEST val);
  50 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  51                                          int regnum, ULONGEST val);
  52
  53 /* Return the register's value in signed or throw if it's not
  54    available.  */
  55
  56 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  57                                         int regnum);
  58
  59 /* Read a register as a signed/unsigned quantity.  */
  60 extern enum register_status
  61   regcache_cooked_read_signed (struct regcache *regcache,
  62                                int regnum, LONGEST *val);
  63 extern enum register_status
  64   regcache_cooked_read_unsigned (struct regcache *regcache,
  65                                  int regnum, ULONGEST *val);
  66 extern void regcache_cooked_write_signed (struct regcache *regcache,
  67                                           int regnum, LONGEST val);
  68 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
  69                                             int regnum, ULONGEST val);
  70
  71 /* Special routines to read/write the PC.  */
  72
  73 /* For regcache_read_pc see gdbsupport/common-regcache.h.  */
  74 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
  75
  76 /* Mapping between register numbers and offsets in a buffer, for use
  77    in the '*regset' functions below and with traditional frame caches.
  78    In an array of 'regcache_map_entry' each element is interpreted
  79    like follows:
  80
  81    - If 'regno' is a register number: Map register 'regno' to the
  82      current offset (starting with 0) and increase the current offset
  83      by 'size' (or the register's size, if 'size' is zero).  Repeat
  84      this with consecutive register numbers up to 'regno+count-1'.
  85
  86      For each described register, if 'size' is larger than the
  87      register's size, the register's value is assumed to be stored in
  88      the first N (where N is the register size) bytes at the current
  89      offset.  The remaining 'size' - N bytes are filled with zeroes by
  90      'regcache_collect_regset' and ignored by other consumers.
  91
  92      If 'size' is smaller than the register's size, only the first
  93      'size' bytes of a register's value are assumed to be stored at
  94      the current offset.  'regcache_collect_regset' copies the first
  95      'size' bytes of a register's value to the output buffer.
  96      'regcache_supply_regset' copies the bytes from the input buffer
  97      into the first 'size' bytes of the register's value leaving the
  98      remaining bytes of the register's value unchanged.  Frame caches
  99      read the 'size' bytes from the stack frame and zero extend them
 100      to generate the register's value.
 101
 102    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
 103      offset.
 104
 105    - If count=0: End of the map.  */
 106
 107 struct regcache_map_entry
 108 {
 109   int count;
 110   int regno;
 111   int size;
 112 };
 113
 114 /* Special value for the 'regno' field in the struct above.  */
 115
 116 enum
 117   {
 118     REGCACHE_MAP_SKIP = -1,
 119   };
 120
 121 /* Calculate and return the total size of all the registers in a
 122    regcache_map_entry.  */
 123
 124 static inline int
 125 regcache_map_entry_size (const struct regcache_map_entry *map)
 126 {
 127   int size = 0;
 128   for (int i = 0; map[i].count != 0; i++)
 129     size += (map[i].count * map[i].size);
 130   return size;
 131 }
 132
 133 /* Transfer a set of registers (as described by REGSET) between
 134    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 135    belonging to the regset, otherwise just the register numbered
 136    REGNUM.  The REGSET's 'regmap' field must point to an array of
 137    'struct regcache_map_entry'.
 138
 139    These functions are suitable for the 'regset_supply' and
 140    'regset_collect' fields in a regset structure.  */
 141
 142 extern void regcache_supply_regset (const struct regset *regset,
 143                                     struct regcache *regcache,
 144                                     int regnum, const void *buf,
 145                                     size_t size);
 146 extern void regcache_collect_regset (const struct regset *regset,
 147                                      const struct regcache *regcache,
 148                                      int regnum, void *buf, size_t size);
 149
 150
 151 /* Return true if a set of registers contains the value of the
 152    register numbered REGNUM.  The size of the set of registers is
 153    given in SIZE, and the layout of the set of registers is described
 154    by MAP.  */
 155
 156 extern bool regcache_map_supplies (const struct regcache_map_entry *map,
 157                                    int regnum, struct gdbarch *gdbarch,
 158                                    size_t size);
 159
 160 /* The type of a register.  This function is slightly more efficient
 161    then its gdbarch vector counterpart since it returns a precomputed
 162    value stored in a table.  */
 163
 164 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 165
 166
 167 /* Return the size of register REGNUM.  All registers should have only
 168    one size.  */
 169
 170 extern int register_size (struct gdbarch *gdbarch, int regnum);
 171
 172 using register_read_ftype
 173   = gdb::function_view<register_status (int, gdb::array_view<gdb_byte>)>;
 174
 175 /* A (register_number, register_value) pair.  */
 176
 177 struct cached_reg_t
 178 {
 179   int num;
 180   gdb::unique_xmalloc_ptr<gdb_byte> data;
 181
 182   cached_reg_t () = default;
 183   cached_reg_t (cached_reg_t &&rhs) = default;
 184 };
 185
 186 /* Buffer of registers.  */
 187
 188 class reg_buffer : public reg_buffer_common
 189 {
 190 public:
 191   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 192
 193   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 194
 195   /* Return regcache's architecture.  */
 196   gdbarch *arch () const;
 197
 198   /* See gdbsupport/common-regcache.h.  */
 199   enum register_status get_register_status (int regnum) const override;
 200
 201   /* See gdbsupport/common-regcache.h.  */
 202   void raw_collect (int regnum, gdb::array_view<gdb_byte> dst) const override;
 203
 204   /* Deprecated overload of the above.  */
 205   void raw_collect (int regnum, void *dst) const;
 206
 207   /* Collect register REGNUM from REGCACHE.  Store collected value as an integer
 208      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 209      If ADDR_LEN is greater than the register size, then the integer will be
 210      sign or zero extended.  If ADDR_LEN is smaller than the register size, then
 211      the most significant bytes of the integer will be truncated.  */
 212   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 213                             bool is_signed) const;
 214
 215   /* Collect part of register REGNUM from this register buffer.  Start at OFFSET
 216      in register.  The size is given by the size of DST.  */
 217   void raw_collect_part (int regnum, int offset,
 218                          gdb::array_view<gdb_byte> dst) const;
 219
 220   /* Deprecated overload of the above.  */
 221   void raw_collect_part (int regnum, int offset, int len, gdb_byte *dst) const
 222   { raw_collect_part (regnum, offset, gdb::make_array_view (dst, len)); }
 223
 224   /* See gdbsupport/common-regcache.h.  */
 225   void raw_supply (int regnum, gdb::array_view<const gdb_byte> src) override;
 226
 227   /* Deprecated overload of the above.  */
 228   void raw_supply (int regnum, const void *src);
 229
 230   void raw_supply (int regnum, const reg_buffer &src)
 231   { raw_supply (regnum, src.register_buffer (regnum)); }
 232
 233   /* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored
 234      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 235      If the register size is greater than ADDR_LEN, then the integer will be
 236      sign or zero extended.  If the register size is smaller than the integer,
 237      then the most significant bytes of the integer will be truncated.  */
 238   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 239                            bool is_signed);
 240
 241   /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
 242      as calling raw_supply with NULL (which will set the state to
 243      unavailable).  */
 244   void raw_supply_zeroed (int regnum);
 245
 246   /* Supply part of register REGNUM to this register buffer.  Start at OFFSET in
 247      the register.  The size is given by the size of SRC.  The rest of the
 248      register left untouched.  */
 249   void raw_supply_part (int regnum, int offset,
 250                         gdb::array_view<const gdb_byte> src);
 251
 252   void invalidate (int regnum);
 253
 254   virtual ~reg_buffer () = default;
 255
 256   /* See gdbsupport/common-regcache.h.  */
 257   bool raw_compare (int regnum, const void *buf, int offset) const override;
 258
 259 protected:
 260   /* Assert on the range of REGNUM.  */
 261   void assert_regnum (int regnum) const;
 262
 263   int num_raw_registers () const;
 264
 265   /* Return a view on register REGNUM's buffer cache.  */
 266   template <typename ElemType>
 267   gdb::array_view<ElemType> register_buffer (int regnum) const;
 268   gdb::array_view<const gdb_byte> register_buffer (int regnum) const;
 269   gdb::array_view<gdb_byte> register_buffer (int regnum);
 270
 271   /* Save a register cache.  The set of registers saved into the
 272      regcache determined by the save_reggroup.  COOKED_READ returns
 273      zero iff the register's value can't be returned.  */
 274   void save (register_read_ftype cooked_read);
 275
 276   struct regcache_descr *m_descr;
 277
 278   bool m_has_pseudo;
 279   /* The register buffers.  */
 280   std::unique_ptr<gdb_byte[]> m_registers;
 281   /* Register cache status.  */
 282   std::unique_ptr<register_status[]> m_register_status;
 283
 284   friend class regcache;
 285   friend class detached_regcache;
 286 };
 287
 288 /* An abstract class which only has methods doing read.  */
 289
 290 class readable_regcache : public reg_buffer
 291 {
 292 public:
 293   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 294     : reg_buffer (gdbarch, has_pseudo)
 295   {}
 296
 297   /* Transfer a raw register [0..NUM_REGS) from core-gdb to this regcache,
 298      return its value in *BUF and return its availability status.  */
 299   register_status raw_read (int regnum, gdb::array_view<gdb_byte> dst);
 300
 301   /* Deprecated overload of the above.  */
 302   register_status raw_read (int regnum, gdb_byte *dst);
 303
 304   template<typename T, typename = RequireLongest<T>>
 305   register_status raw_read (int regnum, T *val);
 306
 307   /* Partial transfer of raw registers.  Return the status of the register.  */
 308   register_status raw_read_part (int regnum, int offset,
 309                                  gdb::array_view<gdb_byte> dst);
 310
 311   /* Deprecated overload of the above.  */
 312   register_status raw_read_part (int regnum, int offset, int len,
 313                                  gdb_byte *dst)
 314   { return raw_read_part (regnum, offset, gdb::make_array_view (dst, len)); }
 315
 316   /* Make certain that the register REGNUM is up-to-date.  */
 317   virtual void raw_update (int regnum) = 0;
 318
 319   /* Transfer a raw register [0..NUM_REGS+NUM_PSEUDO_REGS) from core-gdb to
 320      this regcache, return its value in DST and return its availability status.  */
 321   register_status cooked_read (int regnum, gdb::array_view<gdb_byte> dst);
 322   register_status cooked_read (int regnum, gdb_byte *dst);
 323
 324   template<typename T, typename = RequireLongest<T>>
 325   register_status cooked_read (int regnum, T *val);
 326
 327   /* Partial transfer of a cooked register.  */
 328   register_status cooked_read_part (int regnum, int offset,
 329                                     gdb::array_view<gdb_byte> dst);
 330
 331   /* Deprecated overload of the above.  */
 332   register_status cooked_read_part (int regnum, int offset, int len, gdb_byte *src)
 333   { return cooked_read_part (regnum, offset, gdb::make_array_view (src, len)); }
 334
 335   /* Read register REGNUM from the regcache and return a new value.  This
 336      will call mark_value_bytes_unavailable as appropriate.  */
 337   struct value *cooked_read_value (int regnum);
 338
 339 protected:
 340
 341   /* Perform a partial register transfer using a read, modify, write
 342      operation.  Will fail if register is currently invalid.  */
 343   register_status read_part (int regnum, int offset,
 344                              gdb::array_view<gdb_byte> dst, bool is_raw);
 345 };
 346
 347 /* Buffer of registers, can be read and written.  */
 348
 349 class detached_regcache : public readable_regcache
 350 {
 351 public:
 352   detached_regcache (gdbarch *gdbarch, bool has_pseudo)
 353     : readable_regcache (gdbarch, has_pseudo)
 354   {}
 355
 356   void raw_update (int regnum) override
 357   {}
 358
 359   DISABLE_COPY_AND_ASSIGN (detached_regcache);
 360 };
 361
 362 class readonly_detached_regcache;
 363
 364 /* The register cache for storing raw register values.  */
 365
 366 class regcache : public detached_regcache
 367 {
 368 public:
 369   DISABLE_COPY_AND_ASSIGN (regcache);
 370
 371   /* Restore 'this' regcache.  The set of registers restored into
 372      the regcache determined by the restore_reggroup.
 373      Writes to regcache will go through to the target.  SRC is a
 374      read-only register cache.  */
 375   void restore (readonly_detached_regcache *src);
 376
 377   /* Update the value of raw register REGNUM (in the range [0..NUM_REGS)) and
 378      transfer its value to core-gdb.  */
 379
 380   void raw_write (int regnum, gdb::array_view<const gdb_byte> src);
 381
 382   /* Deprecated overload of the above.  */
 383   void raw_write (int regnum, const gdb_byte *src);
 384
 385   template<typename T, typename = RequireLongest<T>>
 386   void raw_write (int regnum, T val);
 387
 388   /* Transfer of pseudo-registers.  */
 389   void cooked_write (int regnum, gdb::array_view<const gdb_byte> src);
 390
 391   /* Deprecated overload of the above.  */
 392   void cooked_write (int regnum, const gdb_byte *src);
 393
 394   template<typename T, typename = RequireLongest<T>>
 395   void cooked_write (int regnum, T val);
 396
 397   void raw_update (int regnum) override;
 398
 399   /* Partial transfer of raw registers.  Perform read, modify, write style
 400      operations.  */
 401   void raw_write_part (int regnum, int offset,
 402                        gdb::array_view<const gdb_byte> src);
 403
 404   /* Deprecated overload of the above.  */
 405   void raw_write_part (int regnum, int offset, int len, const gdb_byte *src)
 406   { raw_write_part (regnum, offset, gdb::make_array_view (src, len)); }
 407
 408   /* Partial transfer of a cooked register.  Perform read, modify, write style
 409      operations.  */
 410   void cooked_write_part (int regnum, int offset,
 411                           gdb::array_view<const gdb_byte> src);
 412
 413   /* Deprecated overload of the above.  */
 414   void cooked_write_part (int regnum, int offset, int len, const gdb_byte *src)
 415   { cooked_write_part (regnum, offset, gdb::make_array_view (src, len)); }
 416
 417   /* Transfer a set of registers (as described by REGSET) between
 418      REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 419      belonging to the regset, otherwise just the register numbered
 420      REGNUM.  The REGSET's 'regmap' field must point to an array of
 421      'struct regcache_map_entry'.  The valid register numbers in each
 422      entry in 'struct regcache_map_entry' are offset by REGBASE.  */
 423
 424   void supply_regset (const struct regset *regset, int regbase,
 425                       int regnum, const void *buf, size_t size);
 426
 427   void collect_regset (const struct regset *regset, int regbase, int regnum,
 428                        void *buf, size_t size) const;
 429
 430   /* Same as the above, but with REGBASE == 0.  */
 431
 432   void supply_regset (const struct regset *regset,
 433                       int regnum, const void *buf, size_t size)
 434   {
 435     supply_regset (regset, 0, regnum, buf, size);
 436   }
 437
 438   void collect_regset (const struct regset *regset, int regnum,
 439                        void *buf, size_t size) const
 440   {
 441     collect_regset (regset, 0, regnum, buf, size);
 442   }
 443
 444   /* Return REGCACHE's ptid.  */
 445
 446   ptid_t ptid () const
 447   {
 448     gdb_assert (m_ptid != minus_one_ptid);
 449
 450     return m_ptid;
 451   }
 452
 453   void set_ptid (const ptid_t ptid)
 454   {
 455     this->m_ptid = ptid;
 456   }
 457
 458   /* Return a string with the contents of a register, suitable for debug output.  */
 459   std::string register_debug_string (int regno);
 460
 461 protected:
 462   regcache (inferior *inf_for_target_calls, gdbarch *gdbarch);
 463
 464 private:
 465
 466   /* Helper function for transfer_regset.  Copies across a single register.  */
 467   void transfer_regset_register (struct regcache *out_regcache, int regnum,
 468                                  const gdb_byte *in_buf, gdb_byte *out_buf,
 469                                  int slot_size, int offs) const;
 470
 471   /* Transfer a single or all registers belonging to a certain register
 472      set to or from a buffer.  This is the main worker function for
 473      regcache_supply_regset and regcache_collect_regset.  */
 474   void transfer_regset (const struct regset *regset, int regbase,
 475                         struct regcache *out_regcache,
 476                         int regnum, const gdb_byte *in_buf,
 477                         gdb_byte *out_buf, size_t size) const;
 478
 479   /* Perform a partial register transfer using a read, modify, write
 480      operation.  */
 481   register_status write_part (int regnum, int offset,
 482                               gdb::array_view<const gdb_byte> src,
 483                               bool is_raw);
 484
 485   /* The inferior to switch to, to make target calls.
 486
 487      This may not be the inferior of thread M_PTID.  For instance, this
 488      regcache might be for a fork child we are about to detach, so there will
 489      never be an inferior for that thread / process.  Nevertheless, we need to
 490      be able to switch to the target stack that can handle register reads /
 491      writes for this regcache, and that's what this inferior is for.  */
 492   inferior *m_inf_for_target_calls;
 493
 494   /* If this is a read-write cache, which thread's registers is
 495      it connected to?  */
 496   ptid_t m_ptid;
 497
 498   friend regcache *get_thread_arch_regcache (inferior *inf_for_target_calls,
 499                                              ptid_t ptid, gdbarch *gdbarch);
 500 };
 501
 502 using regcache_up = std::unique_ptr<regcache>;
 503
 504 class readonly_detached_regcache : public readable_regcache
 505 {
 506 public:
 507   readonly_detached_regcache (regcache &src);
 508
 509   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 510
 511   readonly_detached_regcache (gdbarch *gdbarch, register_read_ftype cooked_read)
 512     : readable_regcache (gdbarch, true)
 513   {
 514     save (cooked_read);
 515   }
 516
 517   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 518
 519   void raw_update (int regnum) override
 520   {}
 521 };
 522
 523 extern void registers_changed (void);
 524 extern void registers_changed_ptid (process_stratum_target *target,
 525                                     ptid_t ptid);
 526
 527 /* Indicate that registers of THREAD may have changed, so invalidate
 528    the cache.  */
 529 extern void registers_changed_thread (thread_info *thread);
 530
 531 /* An abstract base class for register dump.  */
 532
 533 class register_dump
 534 {
 535 public:
 536   void dump (ui_file *file);
 537   virtual ~register_dump () = default;
 538
 539 protected:
 540   register_dump (gdbarch *arch)
 541     : m_gdbarch (arch)
 542   {}
 543
 544   /* Dump the register REGNUM contents.  If REGNUM is -1, print the
 545      header.  */
 546   virtual void dump_reg (ui_file *file, int regnum) = 0;
 547
 548   gdbarch *m_gdbarch;
 549 };
 550
 551 #endif /* REGCACHE_H */