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 /* The register cache for storing raw register values.  */
 231
 232 class regcache
 233 {
 234 public:
 235   regcache (gdbarch *gdbarch)
 236     : regcache (gdbarch, nullptr, true)
 237   {}
 238
 239   struct readonly_t {};
 240   static constexpr readonly_t readonly {};
 241
 242   /* Create a readonly regcache from a non-readonly regcache.  */
 243   regcache (readonly_t, const regcache &src);
 244
 245   DISABLE_COPY_AND_ASSIGN (regcache);
 246
 247   ~regcache ()
 248   {
 249     xfree (m_registers);
 250     xfree (m_register_status);
 251   }
 252
 253   /* Return regcache's architecture.  */
 254   gdbarch *arch () const;
 255
 256   /* Return REGCACHE's address space.  */
 257   const address_space *aspace () const
 258   {
 259     return m_aspace;
 260   }
 261
 262   void save (regcache_cooked_read_ftype *cooked_read, void *src);
 263
 264   enum register_status cooked_read (int regnum, gdb_byte *buf);
 265   void cooked_write (int regnum, const gdb_byte *buf);
 266
 267   enum register_status raw_read (int regnum, gdb_byte *buf);
 268
 269   void raw_write (int regnum, const gdb_byte *buf);
 270
 271   template<typename T, typename = RequireLongest<T>>
 272   enum register_status raw_read (int regnum, T *val);
 273
 274   template<typename T, typename = RequireLongest<T>>
 275   void raw_write (int regnum, T val);
 276
 277   struct value *cooked_read_value (int regnum);
 278
 279   template<typename T, typename = RequireLongest<T>>
 280   enum register_status cooked_read (int regnum, T *val);
 281
 282   template<typename T, typename = RequireLongest<T>>
 283   void cooked_write (int regnum, T val);
 284
 285   void raw_update (int regnum);
 286
 287   void raw_collect (int regnum, void *buf) const;
 288
 289   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 290                             bool is_signed) const;
 291
 292   void raw_supply (int regnum, const void *buf);
 293
 294   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 295                            bool is_signed);
 296
 297   void raw_supply_zeroed (int regnum);
 298
 299   enum register_status get_register_status (int regnum) const;
 300
 301   void raw_set_cached_value (int regnum, const gdb_byte *buf);
 302
 303   void invalidate (int regnum);
 304
 305   enum register_status raw_read_part (int regnum, int offset, int len,
 306                                       gdb_byte *buf);
 307
 308   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 309
 310   enum register_status cooked_read_part (int regnum, int offset, int len,
 311                                          gdb_byte *buf);
 312
 313   void cooked_write_part (int regnum, int offset, int len,
 314                           const gdb_byte *buf);
 315
 316   void supply_regset (const struct regset *regset,
 317                       int regnum, const void *buf, size_t size);
 318
 319
 320   void collect_regset (const struct regset *regset, int regnum,
 321                        void *buf, size_t size) const;
 322
 323   void dump (ui_file *file, enum regcache_dump_what what_to_dump);
 324
 325   ptid_t ptid () const
 326   {
 327     return m_ptid;
 328   }
 329
 330   void set_ptid (const ptid_t ptid)
 331   {
 332     this->m_ptid = ptid;
 333   }
 334
 335 /* Dump the contents of a register from the register cache to the target
 336    debug.  */
 337   void debug_print_register (const char *func, int regno);
 338
 339   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 340 protected:
 341   regcache (gdbarch *gdbarch, const address_space *aspace_, bool readonly_p_);
 342
 343   int num_raw_registers () const;
 344
 345   static std::forward_list<regcache *> current_regcache;
 346
 347 private:
 348   gdb_byte *register_buffer (int regnum) const;
 349
 350   void restore (struct regcache *src);
 351
 352   enum register_status xfer_part (int regnum, int offset, int len, void *in,
 353                                   const void *out, bool is_raw);
 354
 355   void transfer_regset (const struct regset *regset,
 356                         struct regcache *out_regcache,
 357                         int regnum, const void *in_buf,
 358                         void *out_buf, size_t size) const;
 359
 360   /* Assert on the range of REGNUM.  */
 361   void assert_regnum (int regnum) const;
 362
 363   struct regcache_descr *m_descr;
 364
 365   /* The address space of this register cache (for registers where it
 366      makes sense, like PC or SP).  */
 367   const address_space * const m_aspace;
 368
 369   /* The register buffers.  A read-only register cache can hold the
 370      full [0 .. gdbarch_num_regs + gdbarch_num_pseudo_regs) while a read/write
 371      register cache can only hold [0 .. gdbarch_num_regs).  */
 372   gdb_byte *m_registers;
 373   /* Register cache status.  */
 374   signed char *m_register_status;
 375   /* Is this a read-only cache?  A read-only cache is used for saving
 376      the target's register state (e.g, across an inferior function
 377      call or just before forcing a function return).  A read-only
 378      cache can only be updated via the methods regcache_dup() and
 379      regcache_cpy().  The actual contents are determined by the
 380      reggroup_save and reggroup_restore methods.  */
 381   const bool m_readonly_p;
 382   /* If this is a read-write cache, which thread's registers is
 383      it connected to?  */
 384   ptid_t m_ptid;
 385
 386   friend struct regcache *
 387   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 388                                    struct address_space *aspace);
 389
 390   friend void
 391   registers_changed_ptid (ptid_t ptid);
 392
 393   friend void
 394   regcache_cpy (struct regcache *dst, struct regcache *src);
 395 };
 396
 397 /* Duplicate the contents of a register cache to a read-only register
 398    cache.  The operation is pass-through.  */
 399 extern struct regcache *regcache_dup (struct regcache *regcache);
 400
 401 /* Writes to DEST will go through to the target.  SRC is a read-only
 402    register cache.  */
 403 extern void regcache_cpy (struct regcache *dest, struct regcache *src);
 404
 405 extern void registers_changed (void);
 406 extern void registers_changed_ptid (ptid_t);
 407
 408 #endif /* REGCACHE_H */