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 void regcache_xfree (struct regcache *regcache);
  39 struct cleanup *make_cleanup_regcache_xfree (struct regcache *regcache);
  40 struct regcache *regcache_xmalloc (struct gdbarch *gdbarch,
  41                                    struct address_space *aspace);
  42
  43 /* Return REGCACHE's ptid.  */
  44
  45 extern ptid_t regcache_get_ptid (const struct regcache *regcache);
  46
  47 /* Return REGCACHE's architecture.  */
  48
  49 extern struct gdbarch *get_regcache_arch (const struct regcache *regcache);
  50
  51 /* Return REGCACHE's address space.  */
  52
  53 extern struct address_space *get_regcache_aspace (const struct regcache *);
  54
  55 enum register_status regcache_register_status (const struct regcache *regcache,
  56                                                int regnum);
  57
  58 /* Make certain that the register REGNUM in REGCACHE is up-to-date.  */
  59
  60 void regcache_raw_update (struct regcache *regcache, int regnum);
  61
  62 /* Transfer a raw register [0..NUM_REGS) between core-gdb and the
  63    regcache.  The read variants return the status of the register.  */
  64
  65 enum register_status regcache_raw_read (struct regcache *regcache,
  66                                         int rawnum, gdb_byte *buf);
  67 void regcache_raw_write (struct regcache *regcache, int rawnum,
  68                          const gdb_byte *buf);
  69 extern enum register_status
  70   regcache_raw_read_signed (struct regcache *regcache,
  71                             int regnum, LONGEST *val);
  72
  73 extern void regcache_raw_write_signed (struct regcache *regcache,
  74                                        int regnum, LONGEST val);
  75 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  76                                          int regnum, ULONGEST val);
  77
  78 /* Return the register's value in signed or throw if it's not
  79    available.  */
  80
  81 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  82                                         int regnum);
  83
  84 /* Set a raw register's value in the regcache's buffer.  Unlike
  85    regcache_raw_write, this is not write-through.  The intention is
  86    allowing to change the buffer contents of a read-only regcache
  87    allocated with regcache_xmalloc.  */
  88
  89 extern void regcache_raw_set_cached_value
  90   (struct regcache *regcache, int regnum, const gdb_byte *buf);
  91
  92 /* Partial transfer of raw registers.  These perform read, modify,
  93    write style operations.  The read variant returns the status of the
  94    register.  */
  95
  96 extern enum register_status
  97   regcache_raw_read_part (struct regcache *regcache, int regnum,
  98                           int offset, int len, gdb_byte *buf);
  99 void regcache_raw_write_part (struct regcache *regcache, int regnum,
 100                               int offset, int len, const gdb_byte *buf);
 101
 102 void regcache_invalidate (struct regcache *regcache, int regnum);
 103
 104 /* Transfer of pseudo-registers.  The read variants return a register
 105    status, as an indication of when a ``cooked'' register was
 106    constructed from valid, invalid or unavailable ``raw''
 107    registers.  */
 108
 109 /* Transfer a cooked register [0..NUM_REGS+NUM_PSEUDO_REGS).  */
 110 enum register_status regcache_cooked_read (struct regcache *regcache,
 111                                            int rawnum, gdb_byte *buf);
 112 void regcache_cooked_write (struct regcache *regcache, int rawnum,
 113                             const gdb_byte *buf);
 114
 115 /* Read register REGNUM from REGCACHE and return a new value.  This
 116    will call mark_value_bytes_unavailable as appropriate.  */
 117
 118 struct value *regcache_cooked_read_value (struct regcache *regcache,
 119                                           int regnum);
 120
 121 /* Read a register as a signed/unsigned quantity.  */
 122 extern enum register_status
 123   regcache_cooked_read_signed (struct regcache *regcache,
 124                                int regnum, LONGEST *val);
 125 extern enum register_status
 126   regcache_cooked_read_unsigned (struct regcache *regcache,
 127                                  int regnum, ULONGEST *val);
 128 extern void regcache_cooked_write_signed (struct regcache *regcache,
 129                                           int regnum, LONGEST val);
 130 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
 131                                             int regnum, ULONGEST val);
 132
 133 /* Partial transfer of a cooked register.  These perform read, modify,
 134    write style operations.  */
 135
 136 enum register_status regcache_cooked_read_part (struct regcache *regcache,
 137                                                 int regnum, int offset,
 138                                                 int len, gdb_byte *buf);
 139 void regcache_cooked_write_part (struct regcache *regcache, int regnum,
 140                                  int offset, int len, const gdb_byte *buf);
 141
 142 /* Special routines to read/write the PC.  */
 143
 144 /* For regcache_read_pc see common/common-regcache.h.  */
 145 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
 146
 147 /* Transfer a raw register [0..NUM_REGS) between the regcache and the
 148    target.  These functions are called by the target in response to a
 149    target_fetch_registers() or target_store_registers().  */
 150
 151 extern void regcache_raw_supply (struct regcache *regcache,
 152                                  int regnum, const void *buf);
 153 extern void regcache_raw_collect (const struct regcache *regcache,
 154                                   int regnum, void *buf);
 155
 156 /* Mapping between register numbers and offsets in a buffer, for use
 157    in the '*regset' functions below.  In an array of
 158    'regcache_map_entry' each element is interpreted like follows:
 159
 160    - If 'regno' is a register number: Map register 'regno' to the
 161      current offset (starting with 0) and increase the current offset
 162      by 'size' (or the register's size, if 'size' is zero).  Repeat
 163      this with consecutive register numbers up to 'regno+count-1'.
 164
 165    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
 166      offset.
 167
 168    - If count=0: End of the map.  */
 169
 170 struct regcache_map_entry
 171 {
 172   int count;
 173   int regno;
 174   int size;
 175 };
 176
 177 /* Special value for the 'regno' field in the struct above.  */
 178
 179 enum
 180   {
 181     REGCACHE_MAP_SKIP = -1,
 182   };
 183
 184 /* Transfer a set of registers (as described by REGSET) between
 185    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 186    belonging to the regset, otherwise just the register numbered
 187    REGNUM.  The REGSET's 'regmap' field must point to an array of
 188    'struct regcache_map_entry'.
 189
 190    These functions are suitable for the 'regset_supply' and
 191    'regset_collect' fields in a regset structure.  */
 192
 193 extern void regcache_supply_regset (const struct regset *regset,
 194                                     struct regcache *regcache,
 195                                     int regnum, const void *buf,
 196                                     size_t size);
 197 extern void regcache_collect_regset (const struct regset *regset,
 198                                      const struct regcache *regcache,
 199                                      int regnum, void *buf, size_t size);
 200
 201
 202 /* The type of a register.  This function is slightly more efficient
 203    then its gdbarch vector counterpart since it returns a precomputed
 204    value stored in a table.  */
 205
 206 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 207
 208
 209 /* Return the size of register REGNUM.  All registers should have only
 210    one size.  */
 211
 212 extern int register_size (struct gdbarch *gdbarch, int regnum);
 213
 214
 215 /* Save/restore a register cache.  The set of registers saved /
 216    restored into the DST regcache determined by the save_reggroup /
 217    restore_reggroup respectively.  COOKED_READ returns zero iff the
 218    register's value can't be returned.  */
 219
 220 typedef enum register_status (regcache_cooked_read_ftype) (void *src,
 221                                                            int regnum,
 222                                                            gdb_byte *buf);
 223
 224 extern void regcache_save (struct regcache *dst,
 225                            regcache_cooked_read_ftype *cooked_read,
 226                            void *cooked_read_context);
 227
 228 enum regcache_dump_what
 229 {
 230   regcache_dump_none, regcache_dump_raw,
 231   regcache_dump_cooked, regcache_dump_groups,
 232   regcache_dump_remote
 233 };
 234
 235 /* The register cache for storing raw register values.  */
 236
 237 class regcache
 238 {
 239 public:
 240   regcache (gdbarch *gdbarch, address_space *aspace_)
 241     : regcache (gdbarch, aspace_, true)
 242   {}
 243
 244   struct readonly_t {};
 245   static constexpr readonly_t readonly {};
 246
 247   /* Create a readonly regcache from a non-readonly regcache.  */
 248   regcache (readonly_t, const regcache &src);
 249
 250   regcache (const regcache &) = delete;
 251   void operator= (const regcache &) = delete;
 252
 253   ~regcache ()
 254   {
 255     xfree (m_registers);
 256     xfree (m_register_status);
 257   }
 258
 259   gdbarch *arch () const;
 260
 261   address_space *aspace () const
 262   {
 263     return m_aspace;
 264   }
 265
 266   void save (regcache_cooked_read_ftype *cooked_read, void *src);
 267
 268   enum register_status cooked_read (int regnum, gdb_byte *buf);
 269   void cooked_write (int regnum, const gdb_byte *buf);
 270
 271   enum register_status raw_read (int regnum, gdb_byte *buf);
 272   void raw_write (int regnum, const gdb_byte *buf);
 273
 274   enum register_status raw_read_signed (int regnum, LONGEST *val);
 275
 276   void raw_write_signed (int regnum, LONGEST val);
 277
 278   enum register_status raw_read_unsigned (int regnum, ULONGEST *val);
 279
 280   void raw_write_unsigned (int regnum, ULONGEST val);
 281
 282   struct value *cooked_read_value (int regnum);
 283
 284   enum register_status cooked_read_signed (int regnum, LONGEST *val);
 285
 286   void cooked_write_signed (int regnum, LONGEST val);
 287
 288   enum register_status cooked_read_unsigned (int regnum, ULONGEST *val);
 289
 290   void cooked_write_unsigned (int regnum, ULONGEST val);
 291
 292   void raw_update (int regnum);
 293
 294   void raw_collect (int regnum, void *buf) const;
 295
 296   void raw_supply (int regnum, const void *buf);
 297
 298   void raw_supply_zeroed (int regnum);
 299
 300   enum register_status get_register_status (int regnum) const;
 301
 302   void raw_set_cached_value (int regnum, const gdb_byte *buf);
 303
 304   void invalidate (int regnum);
 305
 306   enum register_status raw_read_part (int regnum, int offset, int len,
 307                                       gdb_byte *buf);
 308
 309   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 310
 311   enum register_status cooked_read_part (int regnum, int offset, int len,
 312                                          gdb_byte *buf);
 313
 314   void cooked_write_part (int regnum, int offset, int len,
 315                           const gdb_byte *buf);
 316
 317   void supply_regset (const struct regset *regset,
 318                       int regnum, const void *buf, size_t size);
 319
 320
 321   void collect_regset (const struct regset *regset, int regnum,
 322                        void *buf, size_t size) const;
 323
 324   void dump (ui_file *file, enum regcache_dump_what what_to_dump);
 325
 326   ptid_t ptid () const
 327   {
 328     return m_ptid;
 329   }
 330
 331   void set_ptid (const ptid_t ptid)
 332   {
 333     this->m_ptid = ptid;
 334   }
 335
 336 /* Dump the contents of a register from the register cache to the target
 337    debug.  */
 338   void debug_print_register (const char *func, int regno);
 339
 340   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 341 protected:
 342   regcache (gdbarch *gdbarch, address_space *aspace_, bool readonly_p_);
 343
 344   static std::forward_list<regcache *> current_regcache;
 345
 346 private:
 347   gdb_byte *register_buffer (int regnum) const;
 348
 349   void restore (struct regcache *src);
 350
 351   void cpy_no_passthrough (struct regcache *src);
 352
 353   enum register_status xfer_part (int regnum, int offset, int len, void *in,
 354                                   const void *out,
 355                                   decltype (regcache_raw_read) read,
 356                                   decltype (regcache_raw_write) write);
 357
 358   void transfer_regset (const struct regset *regset,
 359                         struct regcache *out_regcache,
 360                         int regnum, const void *in_buf,
 361                         void *out_buf, size_t size) 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   struct address_space *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   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 /* Copy/duplicate the contents of a register cache.  By default, the
 398    operation is pass-through.  Writes to DST and reads from SRC will
 399    go through to the target.  See also regcache_cpy_no_passthrough.
 400
 401    regcache_cpy can not have overlapping SRC and DST buffers.  */
 402
 403 extern struct regcache *regcache_dup (struct regcache *regcache);
 404 extern void regcache_cpy (struct regcache *dest, struct regcache *src);
 405
 406 extern void registers_changed (void);
 407 extern void registers_changed_ptid (ptid_t);
 408
 409 #endif /* REGCACHE_H */