gdb/regcache.h

   1 /* Cache and manage the values of registers for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2018 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-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 extern struct regcache *get_thread_arch_regcache (ptid_t, struct gdbarch *);
  34 extern struct regcache *get_thread_arch_aspace_regcache (ptid_t,
  35                                                          struct gdbarch *,
  36                                                          struct address_space *);
  37
  38 /* Return REGCACHE's ptid.  */
  39
  40 extern ptid_t regcache_get_ptid (const struct regcache *regcache);
  41
  42 enum register_status regcache_register_status (const struct regcache *regcache,
  43                                                int regnum);
  44
  45 /* Make certain that the register REGNUM in REGCACHE is up-to-date.  */
  46
  47 void regcache_raw_update (struct regcache *regcache, int regnum);
  48
  49 /* Transfer a raw register [0..NUM_REGS) between core-gdb and the
  50    regcache.  The read variants return the status of the register.  */
  51
  52 enum register_status regcache_raw_read (struct regcache *regcache,
  53                                         int rawnum, gdb_byte *buf);
  54 void regcache_raw_write (struct regcache *regcache, int rawnum,
  55                          const gdb_byte *buf);
  56 extern enum register_status
  57   regcache_raw_read_signed (struct regcache *regcache,
  58                             int regnum, LONGEST *val);
  59
  60 extern void regcache_raw_write_signed (struct regcache *regcache,
  61                                        int regnum, LONGEST val);
  62 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  63                                          int regnum, ULONGEST val);
  64
  65 /* Return the register's value in signed or throw if it's not
  66    available.  */
  67
  68 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  69                                         int regnum);
  70
  71 /* Set a raw register's value in the regcache's buffer.  Unlike
  72    regcache_raw_write, this is not write-through.  The intention is
  73    allowing to change the buffer contents of a read-only regcache
  74    allocated with new.  */
  75
  76 extern void regcache_raw_set_cached_value
  77   (struct regcache *regcache, int regnum, const gdb_byte *buf);
  78
  79 /* Partial transfer of raw registers.  These perform read, modify,
  80    write style operations.  The read variant returns the status of the
  81    register.  */
  82
  83 extern enum register_status
  84   regcache_raw_read_part (struct regcache *regcache, int regnum,
  85                           int offset, int len, gdb_byte *buf);
  86 void regcache_raw_write_part (struct regcache *regcache, int regnum,
  87                               int offset, int len, const gdb_byte *buf);
  88
  89 void regcache_invalidate (struct regcache *regcache, int regnum);
  90
  91 /* Transfer of pseudo-registers.  The read variants return a register
  92    status, as an indication of when a ``cooked'' register was
  93    constructed from valid, invalid or unavailable ``raw''
  94    registers.  */
  95
  96 /* Transfer a cooked register [0..NUM_REGS+NUM_PSEUDO_REGS).  */
  97 enum register_status regcache_cooked_read (struct regcache *regcache,
  98                                            int rawnum, gdb_byte *buf);
  99 void regcache_cooked_write (struct regcache *regcache, int rawnum,
 100                             const gdb_byte *buf);
 101
 102 /* Read register REGNUM from REGCACHE and return a new value.  This
 103    will call mark_value_bytes_unavailable as appropriate.  */
 104
 105 struct value *regcache_cooked_read_value (struct regcache *regcache,
 106                                           int regnum);
 107
 108 /* Read a register as a signed/unsigned quantity.  */
 109 extern enum register_status
 110   regcache_cooked_read_signed (struct regcache *regcache,
 111                                int regnum, LONGEST *val);
 112 extern enum register_status
 113   regcache_cooked_read_unsigned (struct regcache *regcache,
 114                                  int regnum, ULONGEST *val);
 115 extern void regcache_cooked_write_signed (struct regcache *regcache,
 116                                           int regnum, LONGEST val);
 117 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
 118                                             int regnum, ULONGEST val);
 119
 120 /* Partial transfer of a cooked register.  These perform read, modify,
 121    write style operations.  */
 122
 123 enum register_status regcache_cooked_read_part (struct regcache *regcache,
 124                                                 int regnum, int offset,
 125                                                 int len, gdb_byte *buf);
 126 void regcache_cooked_write_part (struct regcache *regcache, int regnum,
 127                                  int offset, int len, const gdb_byte *buf);
 128
 129 /* Special routines to read/write the PC.  */
 130
 131 /* For regcache_read_pc see common/common-regcache.h.  */
 132 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
 133
 134 /* Transfer a raw register [0..NUM_REGS) between the regcache and the
 135    target.  These functions are called by the target in response to a
 136    target_fetch_registers() or target_store_registers().  */
 137
 138 extern void regcache_raw_supply (struct regcache *regcache,
 139                                  int regnum, const void *buf);
 140 extern void regcache_raw_collect (const struct regcache *regcache,
 141                                   int regnum, void *buf);
 142
 143 /* Mapping between register numbers and offsets in a buffer, for use
 144    in the '*regset' functions below.  In an array of
 145    'regcache_map_entry' each element is interpreted like follows:
 146
 147    - If 'regno' is a register number: Map register 'regno' to the
 148      current offset (starting with 0) and increase the current offset
 149      by 'size' (or the register's size, if 'size' is zero).  Repeat
 150      this with consecutive register numbers up to 'regno+count-1'.
 151
 152    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
 153      offset.
 154
 155    - If count=0: End of the map.  */
 156
 157 struct regcache_map_entry
 158 {
 159   int count;
 160   int regno;
 161   int size;
 162 };
 163
 164 /* Special value for the 'regno' field in the struct above.  */
 165
 166 enum
 167   {
 168     REGCACHE_MAP_SKIP = -1,
 169   };
 170
 171 /* Transfer a set of registers (as described by REGSET) between
 172    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 173    belonging to the regset, otherwise just the register numbered
 174    REGNUM.  The REGSET's 'regmap' field must point to an array of
 175    'struct regcache_map_entry'.
 176
 177    These functions are suitable for the 'regset_supply' and
 178    'regset_collect' fields in a regset structure.  */
 179
 180 extern void regcache_supply_regset (const struct regset *regset,
 181                                     struct regcache *regcache,
 182                                     int regnum, const void *buf,
 183                                     size_t size);
 184 extern void regcache_collect_regset (const struct regset *regset,
 185                                      const struct regcache *regcache,
 186                                      int regnum, void *buf, size_t size);
 187
 188
 189 /* The type of a register.  This function is slightly more efficient
 190    then its gdbarch vector counterpart since it returns a precomputed
 191    value stored in a table.  */
 192
 193 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 194
 195
 196 /* Return the size of register REGNUM.  All registers should have only
 197    one size.  */
 198
 199 extern int register_size (struct gdbarch *gdbarch, int regnum);
 200
 201
 202 /* Save/restore a register cache.  The set of registers saved /
 203    restored into the DST regcache determined by the save_reggroup /
 204    restore_reggroup respectively.  COOKED_READ returns zero iff the
 205    register's value can't be returned.  */
 206
 207 typedef enum register_status (regcache_cooked_read_ftype) (void *src,
 208                                                            int regnum,
 209                                                            gdb_byte *buf);
 210
 211 extern void regcache_save (struct regcache *dst,
 212                            regcache_cooked_read_ftype *cooked_read,
 213                            void *cooked_read_context);
 214
 215 enum regcache_dump_what
 216 {
 217   regcache_dump_none, regcache_dump_raw,
 218   regcache_dump_cooked, regcache_dump_groups,
 219   regcache_dump_remote
 220 };
 221
 222 /* A (register_number, register_value) pair.  */
 223
 224 typedef struct cached_reg
 225 {
 226   int num;
 227   gdb_byte *data;
 228 } cached_reg_t;
 229
 230 /* Buffer of registers.  */
 231
 232 class reg_buffer
 233 {
 234 public:
 235   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 236
 237   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 238
 239   /* Return regcache's architecture.  */
 240   gdbarch *arch () const;
 241
 242   virtual ~reg_buffer ()
 243   {
 244     xfree (m_registers);
 245     xfree (m_register_status);
 246   }
 247
 248 protected:
 249   /* Assert on the range of REGNUM.  */
 250   void assert_regnum (int regnum) const;
 251
 252   int num_raw_registers () const;
 253
 254   gdb_byte *register_buffer (int regnum) const;
 255
 256   struct regcache_descr *m_descr;
 257
 258   bool m_has_pseudo;
 259   /* The register buffers.  */
 260   gdb_byte *m_registers;
 261   /* Register cache status.  */
 262   signed char *m_register_status;
 263 };
 264
 265 /* An abstract class which only has methods doing read.  */
 266
 267 class readable_regcache : public reg_buffer
 268 {
 269 public:
 270   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 271     : reg_buffer (gdbarch, has_pseudo)
 272   {}
 273
 274   enum register_status raw_read (int regnum, gdb_byte *buf);
 275   template<typename T, typename = RequireLongest<T>>
 276   enum register_status raw_read (int regnum, T *val);
 277
 278   enum register_status raw_read_part (int regnum, int offset, int len,
 279                                       gdb_byte *buf);
 280
 281   virtual void raw_update (int regnum) = 0;
 282
 283   enum register_status cooked_read (int regnum, gdb_byte *buf);
 284   template<typename T, typename = RequireLongest<T>>
 285   enum register_status cooked_read (int regnum, T *val);
 286
 287   enum register_status cooked_read_part (int regnum, int offset, int len,
 288                                          gdb_byte *buf);
 289
 290   struct value *cooked_read_value (int regnum);
 291
 292 protected:
 293   enum register_status read_part (int regnum, int offset, int len, void *in,
 294                                   bool is_raw);
 295 };
 296
 297 /* The register cache for storing raw register values.  */
 298
 299 class regcache : public readable_regcache
 300 {
 301 public:
 302   regcache (gdbarch *gdbarch)
 303     : regcache (gdbarch, nullptr, true)
 304   {}
 305
 306   struct readonly_t {};
 307   static constexpr readonly_t readonly {};
 308
 309   /* Create a readonly regcache from a non-readonly regcache.  */
 310   regcache (readonly_t, const regcache &src);
 311
 312   DISABLE_COPY_AND_ASSIGN (regcache);
 313
 314   /* Return REGCACHE's address space.  */
 315   const address_space *aspace () const
 316   {
 317     return m_aspace;
 318   }
 319
 320   void save (regcache_cooked_read_ftype *cooked_read, void *src);
 321
 322   void cooked_write (int regnum, const gdb_byte *buf);
 323
 324   void raw_write (int regnum, const gdb_byte *buf);
 325
 326   template<typename T, typename = RequireLongest<T>>
 327   void raw_write (int regnum, T val);
 328
 329   template<typename T, typename = RequireLongest<T>>
 330   void cooked_write (int regnum, T val);
 331
 332   void raw_update (int regnum) override;
 333
 334   void raw_collect (int regnum, void *buf) const;
 335
 336   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 337                             bool is_signed) const;
 338
 339   void raw_supply (int regnum, const void *buf);
 340
 341   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 342                            bool is_signed);
 343
 344   void raw_supply_zeroed (int regnum);
 345
 346   enum register_status get_register_status (int regnum) const;
 347
 348   void raw_set_cached_value (int regnum, const gdb_byte *buf);
 349
 350   void invalidate (int regnum);
 351
 352   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 353
 354   void cooked_write_part (int regnum, int offset, int len,
 355                           const gdb_byte *buf);
 356
 357   void supply_regset (const struct regset *regset,
 358                       int regnum, const void *buf, size_t size);
 359
 360
 361   void collect_regset (const struct regset *regset, int regnum,
 362                        void *buf, size_t size) const;
 363
 364   void dump (ui_file *file, enum regcache_dump_what what_to_dump);
 365
 366   ptid_t ptid () const
 367   {
 368     return m_ptid;
 369   }
 370
 371   void set_ptid (const ptid_t ptid)
 372   {
 373     this->m_ptid = ptid;
 374   }
 375
 376 /* Dump the contents of a register from the register cache to the target
 377    debug.  */
 378   void debug_print_register (const char *func, int regno);
 379
 380   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 381 protected:
 382   regcache (gdbarch *gdbarch, const address_space *aspace_, bool readonly_p_);
 383   static std::forward_list<regcache *> current_regcache;
 384
 385 private:
 386   void restore (struct regcache *src);
 387
 388   void transfer_regset (const struct regset *regset,
 389                         struct regcache *out_regcache,
 390                         int regnum, const void *in_buf,
 391                         void *out_buf, size_t size) const;
 392
 393   enum register_status write_part (int regnum, int offset, int len,
 394                                    const void *out, bool is_raw);
 395
 396
 397   /* The address space of this register cache (for registers where it
 398      makes sense, like PC or SP).  */
 399   const address_space * const m_aspace;
 400
 401   /* Is this a read-only cache?  A read-only cache is used for saving
 402      the target's register state (e.g, across an inferior function
 403      call or just before forcing a function return).  A read-only
 404      cache can only be updated via the methods regcache_dup() and
 405      regcache_cpy().  The actual contents are determined by the
 406      reggroup_save and reggroup_restore methods.  */
 407   const bool m_readonly_p;
 408   /* If this is a read-write cache, which thread's registers is
 409      it connected to?  */
 410   ptid_t m_ptid;
 411
 412   friend struct regcache *
 413   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 414                                    struct address_space *aspace);
 415
 416   friend void
 417   registers_changed_ptid (ptid_t ptid);
 418
 419   friend void
 420   regcache_cpy (struct regcache *dst, struct regcache *src);
 421 };
 422
 423 /* Duplicate the contents of a register cache to a read-only register
 424    cache.  The operation is pass-through.  */
 425 extern struct regcache *regcache_dup (struct regcache *regcache);
 426
 427 /* Writes to DEST will go through to the target.  SRC is a read-only
 428    register cache.  */
 429 extern void regcache_cpy (struct regcache *dest, struct regcache *src);
 430
 431 extern void registers_changed (void);
 432 extern void registers_changed_ptid (ptid_t);
 433
 434 #endif /* REGCACHE_H */