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