gdb/regcache.h

   1 /* Cache and manage the values of registers for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2020 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/common-regcache.h"
  24 #include "gdbsupport/function-view.h"
  25 #include <forward_list>
  26
  27 struct regcache;
  28 struct regset;
  29 struct gdbarch;
  30 struct address_space;
  31 class thread_info;
  32
  33 extern struct regcache *get_current_regcache (void);
  34 extern struct regcache *get_thread_regcache (ptid_t ptid);
  35
  36 /* Get the regcache of THREAD.  */
  37 extern struct regcache *get_thread_regcache (thread_info *thread);
  38
  39 extern struct regcache *get_thread_arch_regcache (ptid_t, struct gdbarch *);
  40 extern struct regcache *get_thread_arch_aspace_regcache (ptid_t,
  41                                                          struct gdbarch *,
  42                                                          struct address_space *);
  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 /* The type of a register.  This function is slightly more efficient
 152    then its gdbarch vector counterpart since it returns a precomputed
 153    value stored in a table.  */
 154
 155 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 156
 157
 158 /* Return the size of register REGNUM.  All registers should have only
 159    one size.  */
 160
 161 extern int register_size (struct gdbarch *gdbarch, int regnum);
 162
 163 typedef gdb::function_view<register_status (int regnum, gdb_byte *buf)>
 164   register_read_ftype;
 165
 166 /* A (register_number, register_value) pair.  */
 167
 168 typedef struct cached_reg
 169 {
 170   int num;
 171   gdb_byte *data;
 172 } cached_reg_t;
 173
 174 /* Buffer of registers.  */
 175
 176 class reg_buffer : public reg_buffer_common
 177 {
 178 public:
 179   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 180
 181   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 182
 183   /* Return regcache's architecture.  */
 184   gdbarch *arch () const;
 185
 186   /* See gdbsupport/common-regcache.h.  */
 187   enum register_status get_register_status (int regnum) const override;
 188
 189   /* See gdbsupport/common-regcache.h.  */
 190   void raw_collect (int regnum, void *buf) const override;
 191
 192   /* Collect register REGNUM from REGCACHE.  Store collected value as an integer
 193      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 194      If ADDR_LEN is greater than the register size, then the integer will be
 195      sign or zero extended.  If ADDR_LEN is smaller than the register size, then
 196      the most significant bytes of the integer will be truncated.  */
 197   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 198                             bool is_signed) const;
 199
 200   /* Collect register REGNUM from REGCACHE, starting at OFFSET in register,
 201      reading only LEN.  */
 202   void raw_collect_part (int regnum, int offset, int len, gdb_byte *out) const;
 203
 204   /* See gdbsupport/common-regcache.h.  */
 205   void raw_supply (int regnum, const void *buf) override;
 206
 207   void raw_supply (int regnum, const reg_buffer &src)
 208   {
 209     raw_supply (regnum, src.register_buffer (regnum));
 210   }
 211
 212   /* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored
 213      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 214      If the register size is greater than ADDR_LEN, then the integer will be
 215      sign or zero extended.  If the register size is smaller than the integer,
 216      then the most significant bytes of the integer will be truncated.  */
 217   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 218                            bool is_signed);
 219
 220   /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
 221      as calling raw_supply with NULL (which will set the state to
 222      unavailable).  */
 223   void raw_supply_zeroed (int regnum);
 224
 225   /* Supply register REGNUM to REGCACHE, starting at OFFSET in register, writing
 226      only LEN, without editing the rest of the register.  */
 227   void raw_supply_part (int regnum, int offset, int len, const gdb_byte *in);
 228
 229   void invalidate (int regnum);
 230
 231   virtual ~reg_buffer () = default;
 232
 233   /* See gdbsupport/common-regcache.h.  */
 234   bool raw_compare (int regnum, const void *buf, int offset) const override;
 235
 236 protected:
 237   /* Assert on the range of REGNUM.  */
 238   void assert_regnum (int regnum) const;
 239
 240   int num_raw_registers () const;
 241
 242   gdb_byte *register_buffer (int regnum) const;
 243
 244   /* Save a register cache.  The set of registers saved into the
 245      regcache determined by the save_reggroup.  COOKED_READ returns
 246      zero iff the register's value can't be returned.  */
 247   void save (register_read_ftype cooked_read);
 248
 249   struct regcache_descr *m_descr;
 250
 251   bool m_has_pseudo;
 252   /* The register buffers.  */
 253   std::unique_ptr<gdb_byte[]> m_registers;
 254   /* Register cache status.  */
 255   std::unique_ptr<register_status[]> m_register_status;
 256
 257   friend class regcache;
 258   friend class detached_regcache;
 259 };
 260
 261 /* An abstract class which only has methods doing read.  */
 262
 263 class readable_regcache : public reg_buffer
 264 {
 265 public:
 266   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 267     : reg_buffer (gdbarch, has_pseudo)
 268   {}
 269
 270   /* Transfer a raw register [0..NUM_REGS) from core-gdb to this regcache,
 271      return its value in *BUF and return its availability status.  */
 272
 273   enum register_status raw_read (int regnum, gdb_byte *buf);
 274   template<typename T, typename = RequireLongest<T>>
 275   enum register_status raw_read (int regnum, T *val);
 276
 277   /* Partial transfer of raw registers.  Return the status of the register.  */
 278   enum register_status raw_read_part (int regnum, int offset, int len,
 279                                       gdb_byte *buf);
 280
 281   /* Make certain that the register REGNUM is up-to-date.  */
 282   virtual void raw_update (int regnum) = 0;
 283
 284   /* Transfer a raw register [0..NUM_REGS+NUM_PSEUDO_REGS) from core-gdb to
 285      this regcache, return its value in *BUF and return its availability status.  */
 286   enum register_status cooked_read (int regnum, gdb_byte *buf);
 287   template<typename T, typename = RequireLongest<T>>
 288   enum register_status cooked_read (int regnum, T *val);
 289
 290   /* Partial transfer of a cooked register.  */
 291   enum register_status cooked_read_part (int regnum, int offset, int len,
 292                                          gdb_byte *buf);
 293
 294   /* Read register REGNUM from the regcache and return a new value.  This
 295      will call mark_value_bytes_unavailable as appropriate.  */
 296   struct value *cooked_read_value (int regnum);
 297
 298 protected:
 299
 300   /* Perform a partial register transfer using a read, modify, write
 301      operation.  Will fail if register is currently invalid.  */
 302   enum register_status read_part (int regnum, int offset, int len,
 303                                   gdb_byte *out, bool is_raw);
 304 };
 305
 306 /* Buffer of registers, can be read and written.  */
 307
 308 class detached_regcache : public readable_regcache
 309 {
 310 public:
 311   detached_regcache (gdbarch *gdbarch, bool has_pseudo)
 312     : readable_regcache (gdbarch, has_pseudo)
 313   {}
 314
 315   void raw_update (int regnum) override
 316   {}
 317
 318   DISABLE_COPY_AND_ASSIGN (detached_regcache);
 319 };
 320
 321 class readonly_detached_regcache;
 322
 323 /* The register cache for storing raw register values.  */
 324
 325 class regcache : public detached_regcache
 326 {
 327 public:
 328   DISABLE_COPY_AND_ASSIGN (regcache);
 329
 330   /* Return REGCACHE's address space.  */
 331   const address_space *aspace () const
 332   {
 333     return m_aspace;
 334   }
 335
 336   /* Restore 'this' regcache.  The set of registers restored into
 337      the regcache determined by the restore_reggroup.
 338      Writes to regcache will go through to the target.  SRC is a
 339      read-only register cache.  */
 340   void restore (readonly_detached_regcache *src);
 341
 342   /* Update the value of raw register REGNUM (in the range [0..NUM_REGS)) and
 343      transfer its value to core-gdb.  */
 344
 345   void raw_write (int regnum, const gdb_byte *buf);
 346
 347   template<typename T, typename = RequireLongest<T>>
 348   void raw_write (int regnum, T val);
 349
 350   /* Transfer of pseudo-registers.  */
 351   void cooked_write (int regnum, const gdb_byte *buf);
 352
 353   template<typename T, typename = RequireLongest<T>>
 354   void cooked_write (int regnum, T val);
 355
 356   void raw_update (int regnum) override;
 357
 358   /* Partial transfer of raw registers.  Perform read, modify, write style
 359      operations.  */
 360   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 361
 362   /* Partial transfer of a cooked register.  Perform read, modify, write style
 363      operations.  */
 364   void cooked_write_part (int regnum, int offset, int len,
 365                           const gdb_byte *buf);
 366
 367   void supply_regset (const struct regset *regset,
 368                       int regnum, const void *buf, size_t size);
 369
 370
 371   void collect_regset (const struct regset *regset, int regnum,
 372                        void *buf, size_t size) const;
 373
 374   /* Return REGCACHE's ptid.  */
 375
 376   ptid_t ptid () const
 377   {
 378     gdb_assert (m_ptid != minus_one_ptid);
 379
 380     return m_ptid;
 381   }
 382
 383   void set_ptid (const ptid_t ptid)
 384   {
 385     this->m_ptid = ptid;
 386   }
 387
 388 /* Dump the contents of a register from the register cache to the target
 389    debug.  */
 390   void debug_print_register (const char *func, int regno);
 391
 392   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 393 protected:
 394   regcache (gdbarch *gdbarch, const address_space *aspace_);
 395
 396   static std::forward_list<regcache *> current_regcache;
 397
 398 private:
 399
 400   /* Helper function for transfer_regset.  Copies across a single register.  */
 401   void transfer_regset_register (struct regcache *out_regcache, int regnum,
 402                                  const gdb_byte *in_buf, gdb_byte *out_buf,
 403                                  int slot_size, int offs) const;
 404
 405   /* Transfer a single or all registers belonging to a certain register
 406      set to or from a buffer.  This is the main worker function for
 407      regcache_supply_regset and regcache_collect_regset.  */
 408   void transfer_regset (const struct regset *regset,
 409                         struct regcache *out_regcache,
 410                         int regnum, const gdb_byte *in_buf,
 411                         gdb_byte *out_buf, size_t size) const;
 412
 413   /* Perform a partial register transfer using a read, modify, write
 414      operation.  */
 415   enum register_status write_part (int regnum, int offset, int len,
 416                                    const gdb_byte *in, bool is_raw);
 417
 418   /* The address space of this register cache (for registers where it
 419      makes sense, like PC or SP).  */
 420   const address_space * const m_aspace;
 421
 422   /* If this is a read-write cache, which thread's registers is
 423      it connected to?  */
 424   ptid_t m_ptid;
 425
 426   friend struct regcache *
 427   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 428                                    struct address_space *aspace);
 429
 430   friend void
 431   registers_changed_ptid (ptid_t ptid);
 432 };
 433
 434 class readonly_detached_regcache : public readable_regcache
 435 {
 436 public:
 437   readonly_detached_regcache (regcache &src);
 438
 439   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 440
 441   readonly_detached_regcache (gdbarch *gdbarch, register_read_ftype cooked_read)
 442     : readable_regcache (gdbarch, true)
 443   {
 444     save (cooked_read);
 445   }
 446
 447   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 448
 449   void raw_update (int regnum) override
 450   {}
 451 };
 452
 453 extern void registers_changed (void);
 454 extern void registers_changed_ptid (ptid_t);
 455
 456 /* Indicate that registers of THREAD may have changed, so invalidate
 457    the cache.  */
 458 extern void registers_changed_thread (thread_info *thread);
 459
 460 /* An abstract base class for register dump.  */
 461
 462 class register_dump
 463 {
 464 public:
 465   void dump (ui_file *file);
 466   virtual ~register_dump () = default;
 467
 468 protected:
 469   register_dump (gdbarch *arch)
 470     : m_gdbarch (arch)
 471   {}
 472
 473   /* Dump the register REGNUM contents.  If REGNUM is -1, print the
 474      header.  */
 475   virtual void dump_reg (ui_file *file, int regnum) = 0;
 476
 477   gdbarch *m_gdbarch;
 478 };
 479
 480 #endif /* REGCACHE_H */