gdb/regcache.h

   1 /* Cache and manage the values of registers for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986-2017 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 /* Return REGCACHE's address space.  */
  43
  44 extern struct address_space *get_regcache_aspace (const struct regcache *);
  45
  46 enum register_status regcache_register_status (const struct regcache *regcache,
  47                                                int regnum);
  48
  49 /* Make certain that the register REGNUM in REGCACHE is up-to-date.  */
  50
  51 void regcache_raw_update (struct regcache *regcache, int regnum);
  52
  53 /* Transfer a raw register [0..NUM_REGS) between core-gdb and the
  54    regcache.  The read variants return the status of the register.  */
  55
  56 enum register_status regcache_raw_read (struct regcache *regcache,
  57                                         int rawnum, gdb_byte *buf);
  58 void regcache_raw_write (struct regcache *regcache, int rawnum,
  59                          const gdb_byte *buf);
  60 extern enum register_status
  61   regcache_raw_read_signed (struct regcache *regcache,
  62                             int regnum, LONGEST *val);
  63
  64 extern void regcache_raw_write_signed (struct regcache *regcache,
  65                                        int regnum, LONGEST val);
  66 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  67                                          int regnum, ULONGEST val);
  68
  69 /* Return the register's value in signed or throw if it's not
  70    available.  */
  71
  72 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  73                                         int regnum);
  74
  75 /* Set a raw register's value in the regcache's buffer.  Unlike
  76    regcache_raw_write, this is not write-through.  The intention is
  77    allowing to change the buffer contents of a read-only regcache
  78    allocated with new.  */
  79
  80 extern void regcache_raw_set_cached_value
  81   (struct regcache *regcache, int regnum, const gdb_byte *buf);
  82
  83 /* Partial transfer of raw registers.  These perform read, modify,
  84    write style operations.  The read variant returns the status of the
  85    register.  */
  86
  87 extern enum register_status
  88   regcache_raw_read_part (struct regcache *regcache, int regnum,
  89                           int offset, int len, gdb_byte *buf);
  90 void regcache_raw_write_part (struct regcache *regcache, int regnum,
  91                               int offset, int len, const gdb_byte *buf);
  92
  93 void regcache_invalidate (struct regcache *regcache, int regnum);
  94
  95 /* Transfer of pseudo-registers.  The read variants return a register
  96    status, as an indication of when a ``cooked'' register was
  97    constructed from valid, invalid or unavailable ``raw''
  98    registers.  */
  99
 100 /* Transfer a cooked register [0..NUM_REGS+NUM_PSEUDO_REGS).  */
 101 enum register_status regcache_cooked_read (struct regcache *regcache,
 102                                            int rawnum, gdb_byte *buf);
 103 void regcache_cooked_write (struct regcache *regcache, int rawnum,
 104                             const gdb_byte *buf);
 105
 106 /* Read register REGNUM from REGCACHE and return a new value.  This
 107    will call mark_value_bytes_unavailable as appropriate.  */
 108
 109 struct value *regcache_cooked_read_value (struct regcache *regcache,
 110                                           int regnum);
 111
 112 /* Read a register as a signed/unsigned quantity.  */
 113 extern enum register_status
 114   regcache_cooked_read_signed (struct regcache *regcache,
 115                                int regnum, LONGEST *val);
 116 extern enum register_status
 117   regcache_cooked_read_unsigned (struct regcache *regcache,
 118                                  int regnum, ULONGEST *val);
 119 extern void regcache_cooked_write_signed (struct regcache *regcache,
 120                                           int regnum, LONGEST val);
 121 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
 122                                             int regnum, ULONGEST val);
 123
 124 /* Partial transfer of a cooked register.  These perform read, modify,
 125    write style operations.  */
 126
 127 enum register_status regcache_cooked_read_part (struct regcache *regcache,
 128                                                 int regnum, int offset,
 129                                                 int len, gdb_byte *buf);
 130 void regcache_cooked_write_part (struct regcache *regcache, int regnum,
 131                                  int offset, int len, const gdb_byte *buf);
 132
 133 /* Special routines to read/write the PC.  */
 134
 135 /* For regcache_read_pc see common/common-regcache.h.  */
 136 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
 137
 138 /* Transfer a raw register [0..NUM_REGS) between the regcache and the
 139    target.  These functions are called by the target in response to a
 140    target_fetch_registers() or target_store_registers().  */
 141
 142 extern void regcache_raw_supply (struct regcache *regcache,
 143                                  int regnum, const void *buf);
 144 extern void regcache_raw_collect (const struct regcache *regcache,
 145                                   int regnum, void *buf);
 146
 147 /* Mapping between register numbers and offsets in a buffer, for use
 148    in the '*regset' functions below.  In an array of
 149    'regcache_map_entry' each element is interpreted like follows:
 150
 151    - If 'regno' is a register number: Map register 'regno' to the
 152      current offset (starting with 0) and increase the current offset
 153      by 'size' (or the register's size, if 'size' is zero).  Repeat
 154      this with consecutive register numbers up to 'regno+count-1'.
 155
 156    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
 157      offset.
 158
 159    - If count=0: End of the map.  */
 160
 161 struct regcache_map_entry
 162 {
 163   int count;
 164   int regno;
 165   int size;
 166 };
 167
 168 /* Special value for the 'regno' field in the struct above.  */
 169
 170 enum
 171   {
 172     REGCACHE_MAP_SKIP = -1,
 173   };
 174
 175 /* Transfer a set of registers (as described by REGSET) between
 176    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 177    belonging to the regset, otherwise just the register numbered
 178    REGNUM.  The REGSET's 'regmap' field must point to an array of
 179    'struct regcache_map_entry'.
 180
 181    These functions are suitable for the 'regset_supply' and
 182    'regset_collect' fields in a regset structure.  */
 183
 184 extern void regcache_supply_regset (const struct regset *regset,
 185                                     struct regcache *regcache,
 186                                     int regnum, const void *buf,
 187                                     size_t size);
 188 extern void regcache_collect_regset (const struct regset *regset,
 189                                      const struct regcache *regcache,
 190                                      int regnum, void *buf, size_t size);
 191
 192
 193 /* The type of a register.  This function is slightly more efficient
 194    then its gdbarch vector counterpart since it returns a precomputed
 195    value stored in a table.  */
 196
 197 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 198
 199
 200 /* Return the size of register REGNUM.  All registers should have only
 201    one size.  */
 202
 203 extern int register_size (struct gdbarch *gdbarch, int regnum);
 204
 205
 206 /* Save/restore a register cache.  The set of registers saved /
 207    restored into the DST regcache determined by the save_reggroup /
 208    restore_reggroup respectively.  COOKED_READ returns zero iff the
 209    register's value can't be returned.  */
 210
 211 typedef enum register_status (regcache_cooked_read_ftype) (void *src,
 212                                                            int regnum,
 213                                                            gdb_byte *buf);
 214
 215 extern void regcache_save (struct regcache *dst,
 216                            regcache_cooked_read_ftype *cooked_read,
 217                            void *cooked_read_context);
 218
 219 enum regcache_dump_what
 220 {
 221   regcache_dump_none, regcache_dump_raw,
 222   regcache_dump_cooked, regcache_dump_groups,
 223   regcache_dump_remote
 224 };
 225
 226 /* A (register_number, register_value) pair.  */
 227
 228 typedef struct cached_reg
 229 {
 230   int num;
 231   gdb_byte *data;
 232 } cached_reg_t;
 233
 234 /* The register cache for storing raw register values.  */
 235
 236 class regcache
 237 {
 238 public:
 239   regcache (gdbarch *gdbarch, address_space *aspace_)
 240     : regcache (gdbarch, aspace_, true)
 241   {}
 242
 243   struct readonly_t {};
 244   static constexpr readonly_t readonly {};
 245
 246   /* Create a readonly regcache from a non-readonly regcache.  */
 247   regcache (readonly_t, const regcache &src);
 248
 249   DISABLE_COPY_AND_ASSIGN (regcache);
 250
 251   ~regcache ()
 252   {
 253     xfree (m_registers);
 254     xfree (m_register_status);
 255   }
 256
 257   /* Return regcache's architecture.  */
 258   gdbarch *arch () const;
 259
 260   address_space *aspace () const
 261   {
 262     return m_aspace;
 263   }
 264
 265   void save (regcache_cooked_read_ftype *cooked_read, void *src);
 266
 267   enum register_status cooked_read (int regnum, gdb_byte *buf);
 268   void cooked_write (int regnum, const gdb_byte *buf);
 269
 270   enum register_status raw_read (int regnum, gdb_byte *buf);
 271
 272   void raw_write (int regnum, const gdb_byte *buf);
 273
 274   template<typename T, typename = RequireLongest<T>>
 275   enum register_status raw_read (int regnum, T *val);
 276
 277   template<typename T, typename = RequireLongest<T>>
 278   void raw_write (int regnum, T val);
 279
 280   struct value *cooked_read_value (int regnum);
 281
 282   template<typename T, typename = RequireLongest<T>>
 283   enum register_status cooked_read (int regnum, T *val);
 284
 285   template<typename T, typename = RequireLongest<T>>
 286   void cooked_write (int regnum, T val);
 287
 288   void raw_update (int regnum);
 289
 290   void raw_collect (int regnum, void *buf) const;
 291
 292   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 293                             bool is_signed) const;
 294
 295   void raw_supply (int regnum, const void *buf);
 296
 297   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 298                            bool is_signed);
 299
 300   void raw_supply_zeroed (int regnum);
 301
 302   enum register_status get_register_status (int regnum) const;
 303
 304   void raw_set_cached_value (int regnum, const gdb_byte *buf);
 305
 306   void invalidate (int regnum);
 307
 308   enum register_status raw_read_part (int regnum, int offset, int len,
 309                                       gdb_byte *buf);
 310
 311   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 312
 313   enum register_status cooked_read_part (int regnum, int offset, int len,
 314                                          gdb_byte *buf);
 315
 316   void cooked_write_part (int regnum, int offset, int len,
 317                           const gdb_byte *buf);
 318
 319   void supply_regset (const struct regset *regset,
 320                       int regnum, const void *buf, size_t size);
 321
 322
 323   void collect_regset (const struct regset *regset, int regnum,
 324                        void *buf, size_t size) const;
 325
 326   void dump (ui_file *file, enum regcache_dump_what what_to_dump);
 327
 328   ptid_t ptid () const
 329   {
 330     return m_ptid;
 331   }
 332
 333   void set_ptid (const ptid_t ptid)
 334   {
 335     this->m_ptid = ptid;
 336   }
 337
 338 /* Dump the contents of a register from the register cache to the target
 339    debug.  */
 340   void debug_print_register (const char *func, int regno);
 341
 342   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 343 protected:
 344   regcache (gdbarch *gdbarch, address_space *aspace_, bool readonly_p_);
 345
 346   static std::forward_list<regcache *> current_regcache;
 347
 348 private:
 349   gdb_byte *register_buffer (int regnum) const;
 350
 351   void restore (struct regcache *src);
 352
 353   enum register_status xfer_part (int regnum, int offset, int len, void *in,
 354                                   const void *out, bool is_raw);
 355
 356   void transfer_regset (const struct regset *regset,
 357                         struct regcache *out_regcache,
 358                         int regnum, const void *in_buf,
 359                         void *out_buf, size_t size) const;
 360
 361   struct regcache_descr *m_descr;
 362
 363   /* The address space of this register cache (for registers where it
 364      makes sense, like PC or SP).  */
 365   struct address_space *m_aspace;
 366
 367   /* The register buffers.  A read-only register cache can hold the
 368      full [0 .. gdbarch_num_regs + gdbarch_num_pseudo_regs) while a read/write
 369      register cache can only hold [0 .. gdbarch_num_regs).  */
 370   gdb_byte *m_registers;
 371   /* Register cache status.  */
 372   signed char *m_register_status;
 373   /* Is this a read-only cache?  A read-only cache is used for saving
 374      the target's register state (e.g, across an inferior function
 375      call or just before forcing a function return).  A read-only
 376      cache can only be updated via the methods regcache_dup() and
 377      regcache_cpy().  The actual contents are determined by the
 378      reggroup_save and reggroup_restore methods.  */
 379   bool m_readonly_p;
 380   /* If this is a read-write cache, which thread's registers is
 381      it connected to?  */
 382   ptid_t m_ptid;
 383
 384   friend struct regcache *
 385   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 386                                    struct address_space *aspace);
 387
 388   friend void
 389   registers_changed_ptid (ptid_t ptid);
 390
 391   friend void
 392   regcache_cpy (struct regcache *dst, struct regcache *src);
 393 };
 394
 395 /* Duplicate the contents of a register cache to a read-only register
 396    cache.  The operation is pass-through.  */
 397 extern struct regcache *regcache_dup (struct regcache *regcache);
 398
 399 /* Writes to DEST will go through to the target.  SRC is a read-only
 400    register cache.  */
 401 extern void regcache_cpy (struct regcache *dest, struct regcache *src);
 402
 403 extern void registers_changed (void);
 404 extern void registers_changed_ptid (ptid_t);
 405
 406 #endif /* REGCACHE_H */