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