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