gdb/regcache.h

   1 /* Cache and manage the values of registers for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2019 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 "common/common-regcache.h"
  24 #include <forward_list>
  25
  26 struct regcache;
  27 struct regset;
  28 struct gdbarch;
  29 struct address_space;
  30
  31 extern struct regcache *get_current_regcache (void);
  32 extern struct regcache *get_thread_regcache (ptid_t ptid);
  33
  34 /* Get the regcache of THREAD.  */
  35 extern struct regcache *get_thread_regcache (thread_info *thread);
  36
  37 extern struct regcache *get_thread_arch_regcache (ptid_t, struct gdbarch *);
  38 extern struct regcache *get_thread_arch_aspace_regcache (ptid_t,
  39                                                          struct gdbarch *,
  40                                                          struct address_space *);
  41
  42 extern enum register_status
  43   regcache_raw_read_signed (struct regcache *regcache,
  44                             int regnum, LONGEST *val);
  45
  46 extern void regcache_raw_write_signed (struct regcache *regcache,
  47                                        int regnum, LONGEST val);
  48 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  49                                          int regnum, ULONGEST val);
  50
  51 /* Return the register's value in signed or throw if it's not
  52    available.  */
  53
  54 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  55                                         int regnum);
  56
  57 /* Read a register as a signed/unsigned quantity.  */
  58 extern enum register_status
  59   regcache_cooked_read_signed (struct regcache *regcache,
  60                                int regnum, LONGEST *val);
  61 extern enum register_status
  62   regcache_cooked_read_unsigned (struct regcache *regcache,
  63                                  int regnum, ULONGEST *val);
  64 extern void regcache_cooked_write_signed (struct regcache *regcache,
  65                                           int regnum, LONGEST val);
  66 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
  67                                             int regnum, ULONGEST val);
  68
  69 /* Special routines to read/write the PC.  */
  70
  71 /* For regcache_read_pc see common/common-regcache.h.  */
  72 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
  73
  74 /* Mapping between register numbers and offsets in a buffer, for use
  75    in the '*regset' functions below and with traditional frame caches.
  76    In an array of 'regcache_map_entry' each element is interpreted
  77    like follows:
  78
  79    - If 'regno' is a register number: Map register 'regno' to the
  80      current offset (starting with 0) and increase the current offset
  81      by 'size' (or the register's size, if 'size' is zero).  Repeat
  82      this with consecutive register numbers up to 'regno+count-1'.
  83
  84      For each described register, if 'size' is larger than the
  85      register's size, the register's value is assumed to be stored in
  86      the first N (where N is the register size) bytes at the current
  87      offset.  The remaining 'size' - N bytes are filled with zeroes by
  88      'regcache_collect_regset' and ignored by other consumers.
  89
  90      If 'size' is smaller than the register's size, only the first
  91      'size' bytes of a register's value are assumed to be stored at
  92      the current offset.  'regcache_collect_regset' copies the first
  93      'size' bytes of a register's value to the output buffer.
  94      'regcache_supply_regset' copies the bytes from the input buffer
  95      into the first 'size' bytes of the register's value leaving the
  96      remaining bytes of the register's value unchanged.  Frame caches
  97      read the 'size' bytes from the stack frame and zero extend them
  98      to generate the register's value.
  99
 100    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
 101      offset.
 102
 103    - If count=0: End of the map.  */
 104
 105 struct regcache_map_entry
 106 {
 107   int count;
 108   int regno;
 109   int size;
 110 };
 111
 112 /* Special value for the 'regno' field in the struct above.  */
 113
 114 enum
 115   {
 116     REGCACHE_MAP_SKIP = -1,
 117   };
 118
 119 /* Calculate and return the total size of all the registers in a
 120    regcache_map_entry.  */
 121
 122 static inline int
 123 regcache_map_entry_size (const struct regcache_map_entry *map)
 124 {
 125   int size = 0;
 126   for (int i = 0; map[i].count != 0; i++)
 127     size += (map[i].count * map[i].size);
 128   return size;
 129 }
 130
 131 /* Transfer a set of registers (as described by REGSET) between
 132    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 133    belonging to the regset, otherwise just the register numbered
 134    REGNUM.  The REGSET's 'regmap' field must point to an array of
 135    'struct regcache_map_entry'.
 136
 137    These functions are suitable for the 'regset_supply' and
 138    'regset_collect' fields in a regset structure.  */
 139
 140 extern void regcache_supply_regset (const struct regset *regset,
 141                                     struct regcache *regcache,
 142                                     int regnum, const void *buf,
 143                                     size_t size);
 144 extern void regcache_collect_regset (const struct regset *regset,
 145                                      const struct regcache *regcache,
 146                                      int regnum, void *buf, size_t size);
 147
 148
 149 /* The type of a register.  This function is slightly more efficient
 150    then its gdbarch vector counterpart since it returns a precomputed
 151    value stored in a table.  */
 152
 153 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 154
 155
 156 /* Return the size of register REGNUM.  All registers should have only
 157    one size.  */
 158
 159 extern int register_size (struct gdbarch *gdbarch, int regnum);
 160
 161 typedef gdb::function_view<register_status (int regnum, gdb_byte *buf)>
 162   register_read_ftype;
 163
 164 /* A (register_number, register_value) pair.  */
 165
 166 typedef struct cached_reg
 167 {
 168   int num;
 169   gdb_byte *data;
 170 } cached_reg_t;
 171
 172 /* Buffer of registers.  */
 173
 174 class reg_buffer : public reg_buffer_common
 175 {
 176 public:
 177   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 178
 179   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 180
 181   /* Return regcache's architecture.  */
 182   gdbarch *arch () const;
 183
 184   /* See common/common-regcache.h.  */
 185   enum register_status get_register_status (int regnum) const override;
 186
 187   /* See common/common-regcache.h.  */
 188   void raw_collect (int regnum, void *buf) const override;
 189
 190   /* Collect register REGNUM from REGCACHE.  Store collected value as an integer
 191      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 192      If ADDR_LEN is greater than the register size, then the integer will be
 193      sign or zero extended.  If ADDR_LEN is smaller than the register size, then
 194      the most significant bytes of the integer will be truncated.  */
 195   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 196                             bool is_signed) const;
 197
 198   /* Collect register REGNUM from REGCACHE, starting at OFFSET in register,
 199      reading only LEN.  */
 200   void raw_collect_part (int regnum, int offset, int len, gdb_byte *out) const;
 201
 202   /* See common/common-regcache.h.  */
 203   void raw_supply (int regnum, const void *buf) override;
 204
 205   void raw_supply (int regnum, const reg_buffer &src)
 206   {
 207     raw_supply (regnum, src.register_buffer (regnum));
 208   }
 209
 210   /* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored
 211      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 212      If the register size is greater than ADDR_LEN, then the integer will be
 213      sign or zero extended.  If the register size is smaller than the integer,
 214      then the most significant bytes of the integer will be truncated.  */
 215   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 216                            bool is_signed);
 217
 218   /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
 219      as calling raw_supply with NULL (which will set the state to
 220      unavailable).  */
 221   void raw_supply_zeroed (int regnum);
 222
 223   /* Supply register REGNUM to REGCACHE, starting at OFFSET in register, writing
 224      only LEN, without editing the rest of the register.  */
 225   void raw_supply_part (int regnum, int offset, int len, const gdb_byte *in);
 226
 227   void invalidate (int regnum);
 228
 229   virtual ~reg_buffer () = default;
 230
 231   /* See common/common-regcache.h.  */
 232   bool raw_compare (int regnum, const void *buf, int offset) const override;
 233
 234 protected:
 235   /* Assert on the range of REGNUM.  */
 236   void assert_regnum (int regnum) const;
 237
 238   int num_raw_registers () const;
 239
 240   gdb_byte *register_buffer (int regnum) const;
 241
 242   /* Save a register cache.  The set of registers saved into the
 243      regcache determined by the save_reggroup.  COOKED_READ returns
 244      zero iff the register's value can't be returned.  */
 245   void save (register_read_ftype cooked_read);
 246
 247   struct regcache_descr *m_descr;
 248
 249   bool m_has_pseudo;
 250   /* The register buffers.  */
 251   std::unique_ptr<gdb_byte[]> m_registers;
 252   /* Register cache status.  */
 253   std::unique_ptr<register_status[]> m_register_status;
 254
 255   friend class regcache;
 256   friend class detached_regcache;
 257 };
 258
 259 /* An abstract class which only has methods doing read.  */
 260
 261 class readable_regcache : public reg_buffer
 262 {
 263 public:
 264   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 265     : reg_buffer (gdbarch, has_pseudo)
 266   {}
 267
 268   /* Transfer a raw register [0..NUM_REGS) from core-gdb to this regcache,
 269      return its value in *BUF and return its availability status.  */
 270
 271   enum register_status raw_read (int regnum, gdb_byte *buf);
 272   template<typename T, typename = RequireLongest<T>>
 273   enum register_status raw_read (int regnum, T *val);
 274
 275   /* Partial transfer of raw registers.  Return the status of the register.  */
 276   enum register_status raw_read_part (int regnum, int offset, int len,
 277                                       gdb_byte *buf);
 278
 279   /* Make certain that the register REGNUM is up-to-date.  */
 280   virtual void raw_update (int regnum) = 0;
 281
 282   /* Transfer a raw register [0..NUM_REGS+NUM_PSEUDO_REGS) from core-gdb to
 283      this regcache, return its value in *BUF and return its availability status.  */
 284   enum register_status cooked_read (int regnum, gdb_byte *buf);
 285   template<typename T, typename = RequireLongest<T>>
 286   enum register_status cooked_read (int regnum, T *val);
 287
 288   /* Partial transfer of a cooked register.  */
 289   enum register_status cooked_read_part (int regnum, int offset, int len,
 290                                          gdb_byte *buf);
 291
 292   /* Read register REGNUM from the regcache and return a new value.  This
 293      will call mark_value_bytes_unavailable as appropriate.  */
 294   struct value *cooked_read_value (int regnum);
 295
 296 protected:
 297
 298   /* Perform a partial register transfer using a read, modify, write
 299      operation.  Will fail if register is currently invalid.  */
 300   enum register_status read_part (int regnum, int offset, int len,
 301                                   gdb_byte *out, bool is_raw);
 302 };
 303
 304 /* Buffer of registers, can be read and written.  */
 305
 306 class detached_regcache : public readable_regcache
 307 {
 308 public:
 309   detached_regcache (gdbarch *gdbarch, bool has_pseudo)
 310     : readable_regcache (gdbarch, has_pseudo)
 311   {}
 312
 313   void raw_update (int regnum) override
 314   {}
 315
 316   DISABLE_COPY_AND_ASSIGN (detached_regcache);
 317 };
 318
 319 class readonly_detached_regcache;
 320
 321 /* The register cache for storing raw register values.  */
 322
 323 class regcache : public detached_regcache
 324 {
 325 public:
 326   DISABLE_COPY_AND_ASSIGN (regcache);
 327
 328   /* Return REGCACHE's address space.  */
 329   const address_space *aspace () const
 330   {
 331     return m_aspace;
 332   }
 333
 334   /* Restore 'this' regcache.  The set of registers restored into
 335      the regcache determined by the restore_reggroup.
 336      Writes to regcache will go through to the target.  SRC is a
 337      read-only register cache.  */
 338   void restore (readonly_detached_regcache *src);
 339
 340   /* Update the value of raw register REGNUM (in the range [0..NUM_REGS)) and
 341      transfer its value to core-gdb.  */
 342
 343   void raw_write (int regnum, const gdb_byte *buf);
 344
 345   template<typename T, typename = RequireLongest<T>>
 346   void raw_write (int regnum, T val);
 347
 348   /* Transfer of pseudo-registers.  */
 349   void cooked_write (int regnum, const gdb_byte *buf);
 350
 351   template<typename T, typename = RequireLongest<T>>
 352   void cooked_write (int regnum, T val);
 353
 354   void raw_update (int regnum) override;
 355
 356   /* Partial transfer of raw registers.  Perform read, modify, write style
 357      operations.  */
 358   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 359
 360   /* Partial transfer of a cooked register.  Perform read, modify, write style
 361      operations.  */
 362   void cooked_write_part (int regnum, int offset, int len,
 363                           const gdb_byte *buf);
 364
 365   void supply_regset (const struct regset *regset,
 366                       int regnum, const void *buf, size_t size);
 367
 368
 369   void collect_regset (const struct regset *regset, int regnum,
 370                        void *buf, size_t size) const;
 371
 372   /* Return REGCACHE's ptid.  */
 373
 374   ptid_t ptid () const
 375   {
 376     gdb_assert (m_ptid != minus_one_ptid);
 377
 378     return m_ptid;
 379   }
 380
 381   void set_ptid (const ptid_t ptid)
 382   {
 383     this->m_ptid = ptid;
 384   }
 385
 386 /* Dump the contents of a register from the register cache to the target
 387    debug.  */
 388   void debug_print_register (const char *func, int regno);
 389
 390   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 391 protected:
 392   regcache (gdbarch *gdbarch, const address_space *aspace_);
 393
 394   static std::forward_list<regcache *> current_regcache;
 395
 396 private:
 397
 398   /* Helper function for transfer_regset.  Copies across a single register.  */
 399   void transfer_regset_register (struct regcache *out_regcache, int regnum,
 400                                  const gdb_byte *in_buf, gdb_byte *out_buf,
 401                                  int slot_size, int offs) const;
 402
 403   /* Transfer a single or all registers belonging to a certain register
 404      set to or from a buffer.  This is the main worker function for
 405      regcache_supply_regset and regcache_collect_regset.  */
 406   void transfer_regset (const struct regset *regset,
 407                         struct regcache *out_regcache,
 408                         int regnum, const gdb_byte *in_buf,
 409                         gdb_byte *out_buf, size_t size) const;
 410
 411   /* Perform a partial register transfer using a read, modify, write
 412      operation.  */
 413   enum register_status write_part (int regnum, int offset, int len,
 414                                    const gdb_byte *in, bool is_raw);
 415
 416   /* The address space of this register cache (for registers where it
 417      makes sense, like PC or SP).  */
 418   const address_space * const m_aspace;
 419
 420   /* If this is a read-write cache, which thread's registers is
 421      it connected to?  */
 422   ptid_t m_ptid;
 423
 424   friend struct regcache *
 425   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 426                                    struct address_space *aspace);
 427
 428   friend void
 429   registers_changed_ptid (ptid_t ptid);
 430 };
 431
 432 class readonly_detached_regcache : public readable_regcache
 433 {
 434 public:
 435   readonly_detached_regcache (regcache &src);
 436
 437   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 438
 439   readonly_detached_regcache (gdbarch *gdbarch, register_read_ftype cooked_read)
 440     : readable_regcache (gdbarch, true)
 441   {
 442     save (cooked_read);
 443   }
 444
 445   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 446
 447   void raw_update (int regnum) override
 448   {}
 449 };
 450
 451 extern void registers_changed (void);
 452 extern void registers_changed_ptid (ptid_t);
 453
 454 /* Indicate that registers of THREAD may have changed, so invalidate
 455    the cache.  */
 456 extern void registers_changed_thread (thread_info *thread);
 457
 458 /* An abstract base class for register dump.  */
 459
 460 class register_dump
 461 {
 462 public:
 463   void dump (ui_file *file);
 464   virtual ~register_dump () = default;
 465
 466 protected:
 467   register_dump (gdbarch *arch)
 468     : m_gdbarch (arch)
 469   {}
 470
 471   /* Dump the register REGNUM contents.  If REGNUM is -1, print the
 472      header.  */
 473   virtual void dump_reg (ui_file *file, int regnum) = 0;
 474
 475   gdbarch *m_gdbarch;
 476 };
 477
 478 #endif /* REGCACHE_H */