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
  34 /* Get the regcache of THREAD.  */
  35 extern struct regcache *get_thread_regcache (thread_info *thread);
  36
  37 extern struct regcache *get_thread_arch_regcache (ptid_t, struct gdbarch *);
  38 extern struct regcache *get_thread_arch_aspace_regcache (ptid_t,
  39                                                          struct gdbarch *,
  40                                                          struct address_space *);
  41
  42 extern enum register_status
  43   regcache_raw_read_signed (struct regcache *regcache,
  44                             int regnum, LONGEST *val);
  45
  46 extern void regcache_raw_write_signed (struct regcache *regcache,
  47                                        int regnum, LONGEST val);
  48 extern void regcache_raw_write_unsigned (struct regcache *regcache,
  49                                          int regnum, ULONGEST val);
  50
  51 /* Return the register's value in signed or throw if it's not
  52    available.  */
  53
  54 extern LONGEST regcache_raw_get_signed (struct regcache *regcache,
  55                                         int regnum);
  56
  57 /* Read a register as a signed/unsigned quantity.  */
  58 extern enum register_status
  59   regcache_cooked_read_signed (struct regcache *regcache,
  60                                int regnum, LONGEST *val);
  61 extern enum register_status
  62   regcache_cooked_read_unsigned (struct regcache *regcache,
  63                                  int regnum, ULONGEST *val);
  64 extern void regcache_cooked_write_signed (struct regcache *regcache,
  65                                           int regnum, LONGEST val);
  66 extern void regcache_cooked_write_unsigned (struct regcache *regcache,
  67                                             int regnum, ULONGEST val);
  68
  69 /* Special routines to read/write the PC.  */
  70
  71 /* For regcache_read_pc see common/common-regcache.h.  */
  72 extern void regcache_write_pc (struct regcache *regcache, CORE_ADDR pc);
  73
  74 /* Mapping between register numbers and offsets in a buffer, for use
  75    in the '*regset' functions below.  In an array of
  76    'regcache_map_entry' each element is interpreted like follows:
  77
  78    - If 'regno' is a register number: Map register 'regno' to the
  79      current offset (starting with 0) and increase the current offset
  80      by 'size' (or the register's size, if 'size' is zero).  Repeat
  81      this with consecutive register numbers up to 'regno+count-1'.
  82
  83    - If 'regno' is REGCACHE_MAP_SKIP: Add 'count*size' to the current
  84      offset.
  85
  86    - If count=0: End of the map.  */
  87
  88 struct regcache_map_entry
  89 {
  90   int count;
  91   int regno;
  92   int size;
  93 };
  94
  95 /* Special value for the 'regno' field in the struct above.  */
  96
  97 enum
  98   {
  99     REGCACHE_MAP_SKIP = -1,
 100   };
 101
 102 /* Transfer a set of registers (as described by REGSET) between
 103    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 104    belonging to the regset, otherwise just the register numbered
 105    REGNUM.  The REGSET's 'regmap' field must point to an array of
 106    'struct regcache_map_entry'.
 107
 108    These functions are suitable for the 'regset_supply' and
 109    'regset_collect' fields in a regset structure.  */
 110
 111 extern void regcache_supply_regset (const struct regset *regset,
 112                                     struct regcache *regcache,
 113                                     int regnum, const void *buf,
 114                                     size_t size);
 115 extern void regcache_collect_regset (const struct regset *regset,
 116                                      const struct regcache *regcache,
 117                                      int regnum, void *buf, size_t size);
 118
 119
 120 /* The type of a register.  This function is slightly more efficient
 121    then its gdbarch vector counterpart since it returns a precomputed
 122    value stored in a table.  */
 123
 124 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 125
 126
 127 /* Return the size of register REGNUM.  All registers should have only
 128    one size.  */
 129
 130 extern int register_size (struct gdbarch *gdbarch, int regnum);
 131
 132 typedef gdb::function_view<register_status (int regnum, gdb_byte *buf)>
 133   register_read_ftype;
 134
 135 /* A (register_number, register_value) pair.  */
 136
 137 typedef struct cached_reg
 138 {
 139   int num;
 140   gdb_byte *data;
 141 } cached_reg_t;
 142
 143 /* Buffer of registers.  */
 144
 145 class reg_buffer : public reg_buffer_common
 146 {
 147 public:
 148   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 149
 150   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 151
 152   /* Return regcache's architecture.  */
 153   gdbarch *arch () const;
 154
 155   /* See common/common-regcache.h.  */
 156   enum register_status get_register_status (int regnum) const override;
 157
 158   /* See common/common-regcache.h.  */
 159   void raw_collect (int regnum, void *buf) const override;
 160
 161   /* Collect register REGNUM from REGCACHE.  Store collected value as an integer
 162      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 163      If ADDR_LEN is greater than the register size, then the integer will be
 164      sign or zero extended.  If ADDR_LEN is smaller than the register size, then
 165      the most significant bytes of the integer will be truncated.  */
 166   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 167                             bool is_signed) const;
 168
 169   /* Collect register REGNUM from REGCACHE, starting at OFFSET in register,
 170      reading only LEN.  */
 171   void raw_collect_part (int regnum, int offset, int len, gdb_byte *out) const;
 172
 173   /* See common/common-regcache.h.  */
 174   void raw_supply (int regnum, const void *buf) override;
 175
 176   void raw_supply (int regnum, const reg_buffer &src)
 177   {
 178     raw_supply (regnum, src.register_buffer (regnum));
 179   }
 180
 181   /* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored
 182      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 183      If the register size is greater than ADDR_LEN, then the integer will be
 184      sign or zero extended.  If the register size is smaller than the integer,
 185      then the most significant bytes of the integer will be truncated.  */
 186   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 187                            bool is_signed);
 188
 189   /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
 190      as calling raw_supply with NULL (which will set the state to
 191      unavailable).  */
 192   void raw_supply_zeroed (int regnum);
 193
 194   /* Supply register REGNUM to REGCACHE, starting at OFFSET in register, writing
 195      only LEN, without editing the rest of the register.  */
 196   void raw_supply_part (int regnum, int offset, int len, const gdb_byte *in);
 197
 198   void invalidate (int regnum);
 199
 200   virtual ~reg_buffer () = default;
 201
 202   /* See common/common-regcache.h.  */
 203   bool raw_compare (int regnum, const void *buf, int offset) const override;
 204
 205 protected:
 206   /* Assert on the range of REGNUM.  */
 207   void assert_regnum (int regnum) const;
 208
 209   int num_raw_registers () const;
 210
 211   gdb_byte *register_buffer (int regnum) const;
 212
 213   /* Save a register cache.  The set of registers saved into the
 214      regcache determined by the save_reggroup.  COOKED_READ returns
 215      zero iff the register's value can't be returned.  */
 216   void save (register_read_ftype cooked_read);
 217
 218   struct regcache_descr *m_descr;
 219
 220   bool m_has_pseudo;
 221   /* The register buffers.  */
 222   std::unique_ptr<gdb_byte[]> m_registers;
 223   /* Register cache status.  */
 224   std::unique_ptr<register_status[]> m_register_status;
 225
 226   friend class regcache;
 227   friend class detached_regcache;
 228 };
 229
 230 /* An abstract class which only has methods doing read.  */
 231
 232 class readable_regcache : public reg_buffer
 233 {
 234 public:
 235   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 236     : reg_buffer (gdbarch, has_pseudo)
 237   {}
 238
 239   /* Transfer a raw register [0..NUM_REGS) from core-gdb to this regcache,
 240      return its value in *BUF and return its availability status.  */
 241
 242   enum register_status raw_read (int regnum, gdb_byte *buf);
 243   template<typename T, typename = RequireLongest<T>>
 244   enum register_status raw_read (int regnum, T *val);
 245
 246   /* Partial transfer of raw registers.  Return the status of the register.  */
 247   enum register_status raw_read_part (int regnum, int offset, int len,
 248                                       gdb_byte *buf);
 249
 250   /* Make certain that the register REGNUM is up-to-date.  */
 251   virtual void raw_update (int regnum) = 0;
 252
 253   /* Transfer a raw register [0..NUM_REGS+NUM_PSEUDO_REGS) from core-gdb to
 254      this regcache, return its value in *BUF and return its availability status.  */
 255   enum register_status cooked_read (int regnum, gdb_byte *buf);
 256   template<typename T, typename = RequireLongest<T>>
 257   enum register_status cooked_read (int regnum, T *val);
 258
 259   /* Partial transfer of a cooked register.  */
 260   enum register_status cooked_read_part (int regnum, int offset, int len,
 261                                          gdb_byte *buf);
 262
 263   /* Read register REGNUM from the regcache and return a new value.  This
 264      will call mark_value_bytes_unavailable as appropriate.  */
 265   struct value *cooked_read_value (int regnum);
 266
 267 protected:
 268
 269   /* Perform a partial register transfer using a read, modify, write
 270      operation.  Will fail if register is currently invalid.  */
 271   enum register_status read_part (int regnum, int offset, int len,
 272                                   gdb_byte *out, bool is_raw);
 273 };
 274
 275 /* Buffer of registers, can be read and written.  */
 276
 277 class detached_regcache : public readable_regcache
 278 {
 279 public:
 280   detached_regcache (gdbarch *gdbarch, bool has_pseudo)
 281     : readable_regcache (gdbarch, has_pseudo)
 282   {}
 283
 284   void raw_update (int regnum) override
 285   {}
 286
 287   DISABLE_COPY_AND_ASSIGN (detached_regcache);
 288 };
 289
 290 class readonly_detached_regcache;
 291
 292 /* The register cache for storing raw register values.  */
 293
 294 class regcache : public detached_regcache
 295 {
 296 public:
 297   DISABLE_COPY_AND_ASSIGN (regcache);
 298
 299   /* Return REGCACHE's address space.  */
 300   const address_space *aspace () const
 301   {
 302     return m_aspace;
 303   }
 304
 305   /* Restore 'this' regcache.  The set of registers restored into
 306      the regcache determined by the restore_reggroup.
 307      Writes to regcache will go through to the target.  SRC is a
 308      read-only register cache.  */
 309   void restore (readonly_detached_regcache *src);
 310
 311   /* Update the value of raw register REGNUM (in the range [0..NUM_REGS)) and
 312      transfer its value to core-gdb.  */
 313
 314   void raw_write (int regnum, const gdb_byte *buf);
 315
 316   template<typename T, typename = RequireLongest<T>>
 317   void raw_write (int regnum, T val);
 318
 319   /* Transfer of pseudo-registers.  */
 320   void cooked_write (int regnum, const gdb_byte *buf);
 321
 322   template<typename T, typename = RequireLongest<T>>
 323   void cooked_write (int regnum, T val);
 324
 325   void raw_update (int regnum) override;
 326
 327   /* Partial transfer of raw registers.  Perform read, modify, write style
 328      operations.  */
 329   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 330
 331   /* Partial transfer of a cooked register.  Perform read, modify, write style
 332      operations.  */
 333   void cooked_write_part (int regnum, int offset, int len,
 334                           const gdb_byte *buf);
 335
 336   void supply_regset (const struct regset *regset,
 337                       int regnum, const void *buf, size_t size);
 338
 339
 340   void collect_regset (const struct regset *regset, int regnum,
 341                        void *buf, size_t size) const;
 342
 343   /* Return REGCACHE's ptid.  */
 344
 345   ptid_t ptid () const
 346   {
 347     gdb_assert (m_ptid != minus_one_ptid);
 348
 349     return m_ptid;
 350   }
 351
 352   void set_ptid (const ptid_t ptid)
 353   {
 354     this->m_ptid = ptid;
 355   }
 356
 357 /* Dump the contents of a register from the register cache to the target
 358    debug.  */
 359   void debug_print_register (const char *func, int regno);
 360
 361   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 362 protected:
 363   regcache (gdbarch *gdbarch, const address_space *aspace_);
 364
 365   static std::forward_list<regcache *> current_regcache;
 366
 367 private:
 368
 369   /* Helper function for transfer_regset.  Copies across a single register.  */
 370   void transfer_regset_register (struct regcache *out_regcache, int regnum,
 371                                  const gdb_byte *in_buf, gdb_byte *out_buf,
 372                                  int slot_size, int offs) const;
 373
 374   /* Transfer a single or all registers belonging to a certain register
 375      set to or from a buffer.  This is the main worker function for
 376      regcache_supply_regset and regcache_collect_regset.  */
 377   void transfer_regset (const struct regset *regset,
 378                         struct regcache *out_regcache,
 379                         int regnum, const gdb_byte *in_buf,
 380                         gdb_byte *out_buf, size_t size) const;
 381
 382   /* Perform a partial register transfer using a read, modify, write
 383      operation.  */
 384   enum register_status write_part (int regnum, int offset, int len,
 385                                    const gdb_byte *in, bool is_raw);
 386
 387   /* The address space of this register cache (for registers where it
 388      makes sense, like PC or SP).  */
 389   const address_space * const m_aspace;
 390
 391   /* If this is a read-write cache, which thread's registers is
 392      it connected to?  */
 393   ptid_t m_ptid;
 394
 395   friend struct regcache *
 396   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 397                                    struct address_space *aspace);
 398
 399   friend void
 400   registers_changed_ptid (ptid_t ptid);
 401 };
 402
 403 class readonly_detached_regcache : public readable_regcache
 404 {
 405 public:
 406   readonly_detached_regcache (regcache &src);
 407
 408   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 409
 410   readonly_detached_regcache (gdbarch *gdbarch, register_read_ftype cooked_read)
 411     : readable_regcache (gdbarch, true)
 412   {
 413     save (cooked_read);
 414   }
 415
 416   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 417
 418   void raw_update (int regnum) override
 419   {}
 420 };
 421
 422 extern void registers_changed (void);
 423 extern void registers_changed_ptid (ptid_t);
 424
 425 /* Indicate that registers of THREAD may have changed, so invalidate
 426    the cache.  */
 427 extern void registers_changed_thread (thread_info *thread);
 428
 429 /* An abstract base class for register dump.  */
 430
 431 class register_dump
 432 {
 433 public:
 434   void dump (ui_file *file);
 435   virtual ~register_dump () = default;
 436
 437 protected:
 438   register_dump (gdbarch *arch)
 439     : m_gdbarch (arch)
 440   {}
 441
 442   /* Dump the register REGNUM contents.  If REGNUM is -1, print the
 443      header.  */
 444   virtual void dump_reg (ui_file *file, int regnum) = 0;
 445
 446   gdbarch *m_gdbarch;
 447 };
 448
 449 #endif /* REGCACHE_H */