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 typedef enum register_status (regcache_cooked_read_ftype) (void *src,
 202                                                            int regnum,
 203                                                            gdb_byte *buf);
 204
 205 enum regcache_dump_what
 206 {
 207   regcache_dump_none, regcache_dump_raw,
 208   regcache_dump_cooked, regcache_dump_groups,
 209   regcache_dump_remote
 210 };
 211
 212 /* A (register_number, register_value) pair.  */
 213
 214 typedef struct cached_reg
 215 {
 216   int num;
 217   gdb_byte *data;
 218 } cached_reg_t;
 219
 220 /* Buffer of registers.  */
 221
 222 class reg_buffer
 223 {
 224 public:
 225   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 226
 227   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 228
 229   /* Return regcache's architecture.  */
 230   gdbarch *arch () const;
 231
 232   virtual ~reg_buffer ()
 233   {
 234     xfree (m_registers);
 235     xfree (m_register_status);
 236   }
 237
 238 protected:
 239   /* Assert on the range of REGNUM.  */
 240   void assert_regnum (int regnum) const;
 241
 242   int num_raw_registers () const;
 243
 244   gdb_byte *register_buffer (int regnum) const;
 245
 246   /* Save a register cache.  The set of registers saved into the
 247      regcache determined by the save_reggroup.  COOKED_READ returns
 248      zero iff the register's value can't be returned.  */
 249   void save (regcache_cooked_read_ftype *cooked_read, void *src);
 250
 251   struct regcache_descr *m_descr;
 252
 253   bool m_has_pseudo;
 254   /* The register buffers.  */
 255   gdb_byte *m_registers;
 256   /* Register cache status.  */
 257   signed char *m_register_status;
 258
 259   friend class regcache;
 260 };
 261
 262 /* An abstract class which only has methods doing read.  */
 263
 264 class readable_regcache : public reg_buffer
 265 {
 266 public:
 267   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 268     : reg_buffer (gdbarch, has_pseudo)
 269   {}
 270
 271   enum register_status raw_read (int regnum, gdb_byte *buf);
 272   template<typename T, typename = RequireLongest<T>>
 273   enum register_status raw_read (int regnum, T *val);
 274
 275   enum register_status raw_read_part (int regnum, int offset, int len,
 276                                       gdb_byte *buf);
 277
 278   virtual void raw_update (int regnum) = 0;
 279
 280   enum register_status cooked_read (int regnum, gdb_byte *buf);
 281   template<typename T, typename = RequireLongest<T>>
 282   enum register_status cooked_read (int regnum, T *val);
 283
 284   enum register_status cooked_read_part (int regnum, int offset, int len,
 285                                          gdb_byte *buf);
 286
 287   struct value *cooked_read_value (int regnum);
 288
 289 protected:
 290   enum register_status read_part (int regnum, int offset, int len, void *in,
 291                                   bool is_raw);
 292 };
 293
 294 class readonly_detached_regcache;
 295
 296 /* The register cache for storing raw register values.  */
 297
 298 class regcache : public readable_regcache
 299 {
 300 public:
 301   regcache (gdbarch *gdbarch)
 302     : regcache (gdbarch, nullptr, true)
 303   {}
 304
 305   struct readonly_t {};
 306   static constexpr readonly_t readonly {};
 307
 308   /* Create a readonly regcache from a non-readonly regcache.  */
 309   regcache (readonly_t, const regcache &src);
 310
 311   DISABLE_COPY_AND_ASSIGN (regcache);
 312
 313   /* Return REGCACHE's address space.  */
 314   const address_space *aspace () const
 315   {
 316     return m_aspace;
 317   }
 318
 319   /* Restore 'this' regcache.  The set of registers restored into
 320      the regcache determined by the restore_reggroup.
 321      Writes to regcache will go through to the target.  SRC is a
 322      read-only register cache.  */
 323   void restore (readonly_detached_regcache *src);
 324
 325   void cooked_write (int regnum, const gdb_byte *buf);
 326
 327   void raw_write (int regnum, const gdb_byte *buf);
 328
 329   template<typename T, typename = RequireLongest<T>>
 330   void raw_write (int regnum, T val);
 331
 332   template<typename T, typename = RequireLongest<T>>
 333   void cooked_write (int regnum, T val);
 334
 335   void raw_update (int regnum) override;
 336
 337   void raw_collect (int regnum, void *buf) const;
 338
 339   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 340                             bool is_signed) const;
 341
 342   void raw_supply (int regnum, const void *buf);
 343
 344   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 345                            bool is_signed);
 346
 347   void raw_supply_zeroed (int regnum);
 348
 349   enum register_status get_register_status (int regnum) const;
 350
 351   void raw_set_cached_value (int regnum, const gdb_byte *buf);
 352
 353   void invalidate (int regnum);
 354
 355   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 356
 357   void cooked_write_part (int regnum, int offset, int len,
 358                           const gdb_byte *buf);
 359
 360   void supply_regset (const struct regset *regset,
 361                       int regnum, const void *buf, size_t size);
 362
 363
 364   void collect_regset (const struct regset *regset, int regnum,
 365                        void *buf, size_t size) const;
 366
 367   void dump (ui_file *file, enum regcache_dump_what what_to_dump);
 368
 369   ptid_t ptid () const
 370   {
 371     return m_ptid;
 372   }
 373
 374   void set_ptid (const ptid_t ptid)
 375   {
 376     this->m_ptid = ptid;
 377   }
 378
 379 /* Dump the contents of a register from the register cache to the target
 380    debug.  */
 381   void debug_print_register (const char *func, int regno);
 382
 383   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 384 protected:
 385   regcache (gdbarch *gdbarch, const address_space *aspace_, bool readonly_p_);
 386   static std::forward_list<regcache *> current_regcache;
 387
 388 private:
 389
 390   void transfer_regset (const struct regset *regset,
 391                         struct regcache *out_regcache,
 392                         int regnum, const void *in_buf,
 393                         void *out_buf, size_t size) const;
 394
 395   enum register_status write_part (int regnum, int offset, int len,
 396                                    const void *out, bool is_raw);
 397
 398
 399   /* The address space of this register cache (for registers where it
 400      makes sense, like PC or SP).  */
 401   const address_space * const m_aspace;
 402
 403   /* Is this a read-only cache?  A read-only cache is used for saving
 404      the target's register state (e.g, across an inferior function
 405      call or just before forcing a function return).  A read-only
 406      cache can only be created via a constructor.  The actual contents
 407      are determined by the save and restore methods.  */
 408   const bool m_readonly_p;
 409   /* If this is a read-write cache, which thread's registers is
 410      it connected to?  */
 411   ptid_t m_ptid;
 412
 413   friend struct regcache *
 414   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 415                                    struct address_space *aspace);
 416
 417   friend void
 418   registers_changed_ptid (ptid_t ptid);
 419 };
 420
 421 class readonly_detached_regcache : public readable_regcache
 422 {
 423 public:
 424   readonly_detached_regcache (const regcache &src);
 425
 426   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 427
 428   readonly_detached_regcache (gdbarch *gdbarch,
 429                               regcache_cooked_read_ftype *cooked_read,
 430                               void *src)
 431     : readable_regcache (gdbarch, true)
 432   {
 433     save (cooked_read, src);
 434   }
 435
 436   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 437
 438   void raw_update (int regnum) override
 439   {}
 440 };
 441
 442 extern void registers_changed (void);
 443 extern void registers_changed_ptid (ptid_t);
 444
 445 #endif /* REGCACHE_H */