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 /* Calculate and return the total size of all the registers in a
 103    regcache_map_entry.  */
 104
 105 static inline int
 106 regcache_map_entry_size (const struct regcache_map_entry *map)
 107 {
 108   int size = 0;
 109   for (int i = 0; map[i].count != 0; i++)
 110     size += (map[i].count * map[i].size);
 111   return size;
 112 }
 113
 114 /* Transfer a set of registers (as described by REGSET) between
 115    REGCACHE and BUF.  If REGNUM == -1, transfer all registers
 116    belonging to the regset, otherwise just the register numbered
 117    REGNUM.  The REGSET's 'regmap' field must point to an array of
 118    'struct regcache_map_entry'.
 119
 120    These functions are suitable for the 'regset_supply' and
 121    'regset_collect' fields in a regset structure.  */
 122
 123 extern void regcache_supply_regset (const struct regset *regset,
 124                                     struct regcache *regcache,
 125                                     int regnum, const void *buf,
 126                                     size_t size);
 127 extern void regcache_collect_regset (const struct regset *regset,
 128                                      const struct regcache *regcache,
 129                                      int regnum, void *buf, size_t size);
 130
 131
 132 /* The type of a register.  This function is slightly more efficient
 133    then its gdbarch vector counterpart since it returns a precomputed
 134    value stored in a table.  */
 135
 136 extern struct type *register_type (struct gdbarch *gdbarch, int regnum);
 137
 138
 139 /* Return the size of register REGNUM.  All registers should have only
 140    one size.  */
 141
 142 extern int register_size (struct gdbarch *gdbarch, int regnum);
 143
 144 typedef gdb::function_view<register_status (int regnum, gdb_byte *buf)>
 145   register_read_ftype;
 146
 147 /* A (register_number, register_value) pair.  */
 148
 149 typedef struct cached_reg
 150 {
 151   int num;
 152   gdb_byte *data;
 153 } cached_reg_t;
 154
 155 /* Buffer of registers.  */
 156
 157 class reg_buffer : public reg_buffer_common
 158 {
 159 public:
 160   reg_buffer (gdbarch *gdbarch, bool has_pseudo);
 161
 162   DISABLE_COPY_AND_ASSIGN (reg_buffer);
 163
 164   /* Return regcache's architecture.  */
 165   gdbarch *arch () const;
 166
 167   /* See common/common-regcache.h.  */
 168   enum register_status get_register_status (int regnum) const override;
 169
 170   /* See common/common-regcache.h.  */
 171   void raw_collect (int regnum, void *buf) const override;
 172
 173   /* Collect register REGNUM from REGCACHE.  Store collected value as an integer
 174      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 175      If ADDR_LEN is greater than the register size, then the integer will be
 176      sign or zero extended.  If ADDR_LEN is smaller than the register size, then
 177      the most significant bytes of the integer will be truncated.  */
 178   void raw_collect_integer (int regnum, gdb_byte *addr, int addr_len,
 179                             bool is_signed) const;
 180
 181   /* Collect register REGNUM from REGCACHE, starting at OFFSET in register,
 182      reading only LEN.  */
 183   void raw_collect_part (int regnum, int offset, int len, gdb_byte *out) const;
 184
 185   /* See common/common-regcache.h.  */
 186   void raw_supply (int regnum, const void *buf) override;
 187
 188   void raw_supply (int regnum, const reg_buffer &src)
 189   {
 190     raw_supply (regnum, src.register_buffer (regnum));
 191   }
 192
 193   /* Supply register REGNUM to REGCACHE.  Value to supply is an integer stored
 194      at address ADDR, in target endian, with length ADDR_LEN and sign IS_SIGNED.
 195      If the register size is greater than ADDR_LEN, then the integer will be
 196      sign or zero extended.  If the register size is smaller than the integer,
 197      then the most significant bytes of the integer will be truncated.  */
 198   void raw_supply_integer (int regnum, const gdb_byte *addr, int addr_len,
 199                            bool is_signed);
 200
 201   /* Supply register REGNUM with zeroed value to REGCACHE.  This is not the same
 202      as calling raw_supply with NULL (which will set the state to
 203      unavailable).  */
 204   void raw_supply_zeroed (int regnum);
 205
 206   /* Supply register REGNUM to REGCACHE, starting at OFFSET in register, writing
 207      only LEN, without editing the rest of the register.  */
 208   void raw_supply_part (int regnum, int offset, int len, const gdb_byte *in);
 209
 210   void invalidate (int regnum);
 211
 212   virtual ~reg_buffer () = default;
 213
 214   /* See common/common-regcache.h.  */
 215   bool raw_compare (int regnum, const void *buf, int offset) const override;
 216
 217 protected:
 218   /* Assert on the range of REGNUM.  */
 219   void assert_regnum (int regnum) const;
 220
 221   int num_raw_registers () const;
 222
 223   gdb_byte *register_buffer (int regnum) const;
 224
 225   /* Save a register cache.  The set of registers saved into the
 226      regcache determined by the save_reggroup.  COOKED_READ returns
 227      zero iff the register's value can't be returned.  */
 228   void save (register_read_ftype cooked_read);
 229
 230   struct regcache_descr *m_descr;
 231
 232   bool m_has_pseudo;
 233   /* The register buffers.  */
 234   std::unique_ptr<gdb_byte[]> m_registers;
 235   /* Register cache status.  */
 236   std::unique_ptr<register_status[]> m_register_status;
 237
 238   friend class regcache;
 239   friend class detached_regcache;
 240 };
 241
 242 /* An abstract class which only has methods doing read.  */
 243
 244 class readable_regcache : public reg_buffer
 245 {
 246 public:
 247   readable_regcache (gdbarch *gdbarch, bool has_pseudo)
 248     : reg_buffer (gdbarch, has_pseudo)
 249   {}
 250
 251   /* Transfer a raw register [0..NUM_REGS) from core-gdb to this regcache,
 252      return its value in *BUF and return its availability status.  */
 253
 254   enum register_status raw_read (int regnum, gdb_byte *buf);
 255   template<typename T, typename = RequireLongest<T>>
 256   enum register_status raw_read (int regnum, T *val);
 257
 258   /* Partial transfer of raw registers.  Return the status of the register.  */
 259   enum register_status raw_read_part (int regnum, int offset, int len,
 260                                       gdb_byte *buf);
 261
 262   /* Make certain that the register REGNUM is up-to-date.  */
 263   virtual void raw_update (int regnum) = 0;
 264
 265   /* Transfer a raw register [0..NUM_REGS+NUM_PSEUDO_REGS) from core-gdb to
 266      this regcache, return its value in *BUF and return its availability status.  */
 267   enum register_status cooked_read (int regnum, gdb_byte *buf);
 268   template<typename T, typename = RequireLongest<T>>
 269   enum register_status cooked_read (int regnum, T *val);
 270
 271   /* Partial transfer of a cooked register.  */
 272   enum register_status cooked_read_part (int regnum, int offset, int len,
 273                                          gdb_byte *buf);
 274
 275   /* Read register REGNUM from the regcache and return a new value.  This
 276      will call mark_value_bytes_unavailable as appropriate.  */
 277   struct value *cooked_read_value (int regnum);
 278
 279 protected:
 280
 281   /* Perform a partial register transfer using a read, modify, write
 282      operation.  Will fail if register is currently invalid.  */
 283   enum register_status read_part (int regnum, int offset, int len,
 284                                   gdb_byte *out, bool is_raw);
 285 };
 286
 287 /* Buffer of registers, can be read and written.  */
 288
 289 class detached_regcache : public readable_regcache
 290 {
 291 public:
 292   detached_regcache (gdbarch *gdbarch, bool has_pseudo)
 293     : readable_regcache (gdbarch, has_pseudo)
 294   {}
 295
 296   void raw_update (int regnum) override
 297   {}
 298
 299   DISABLE_COPY_AND_ASSIGN (detached_regcache);
 300 };
 301
 302 class readonly_detached_regcache;
 303
 304 /* The register cache for storing raw register values.  */
 305
 306 class regcache : public detached_regcache
 307 {
 308 public:
 309   DISABLE_COPY_AND_ASSIGN (regcache);
 310
 311   /* Return REGCACHE's address space.  */
 312   const address_space *aspace () const
 313   {
 314     return m_aspace;
 315   }
 316
 317   /* Restore 'this' regcache.  The set of registers restored into
 318      the regcache determined by the restore_reggroup.
 319      Writes to regcache will go through to the target.  SRC is a
 320      read-only register cache.  */
 321   void restore (readonly_detached_regcache *src);
 322
 323   /* Update the value of raw register REGNUM (in the range [0..NUM_REGS)) and
 324      transfer its value to core-gdb.  */
 325
 326   void raw_write (int regnum, const gdb_byte *buf);
 327
 328   template<typename T, typename = RequireLongest<T>>
 329   void raw_write (int regnum, T val);
 330
 331   /* Transfer of pseudo-registers.  */
 332   void cooked_write (int regnum, const gdb_byte *buf);
 333
 334   template<typename T, typename = RequireLongest<T>>
 335   void cooked_write (int regnum, T val);
 336
 337   void raw_update (int regnum) override;
 338
 339   /* Partial transfer of raw registers.  Perform read, modify, write style
 340      operations.  */
 341   void raw_write_part (int regnum, int offset, int len, const gdb_byte *buf);
 342
 343   /* Partial transfer of a cooked register.  Perform read, modify, write style
 344      operations.  */
 345   void cooked_write_part (int regnum, int offset, int len,
 346                           const gdb_byte *buf);
 347
 348   void supply_regset (const struct regset *regset,
 349                       int regnum, const void *buf, size_t size);
 350
 351
 352   void collect_regset (const struct regset *regset, int regnum,
 353                        void *buf, size_t size) const;
 354
 355   /* Return REGCACHE's ptid.  */
 356
 357   ptid_t ptid () const
 358   {
 359     gdb_assert (m_ptid != minus_one_ptid);
 360
 361     return m_ptid;
 362   }
 363
 364   void set_ptid (const ptid_t ptid)
 365   {
 366     this->m_ptid = ptid;
 367   }
 368
 369 /* Dump the contents of a register from the register cache to the target
 370    debug.  */
 371   void debug_print_register (const char *func, int regno);
 372
 373   static void regcache_thread_ptid_changed (ptid_t old_ptid, ptid_t new_ptid);
 374 protected:
 375   regcache (gdbarch *gdbarch, const address_space *aspace_);
 376
 377   static std::forward_list<regcache *> current_regcache;
 378
 379 private:
 380
 381   /* Helper function for transfer_regset.  Copies across a single register.  */
 382   void transfer_regset_register (struct regcache *out_regcache, int regnum,
 383                                  const gdb_byte *in_buf, gdb_byte *out_buf,
 384                                  int slot_size, int offs) const;
 385
 386   /* Transfer a single or all registers belonging to a certain register
 387      set to or from a buffer.  This is the main worker function for
 388      regcache_supply_regset and regcache_collect_regset.  */
 389   void transfer_regset (const struct regset *regset,
 390                         struct regcache *out_regcache,
 391                         int regnum, const gdb_byte *in_buf,
 392                         gdb_byte *out_buf, size_t size) const;
 393
 394   /* Perform a partial register transfer using a read, modify, write
 395      operation.  */
 396   enum register_status write_part (int regnum, int offset, int len,
 397                                    const gdb_byte *in, bool is_raw);
 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   /* If this is a read-write cache, which thread's registers is
 404      it connected to?  */
 405   ptid_t m_ptid;
 406
 407   friend struct regcache *
 408   get_thread_arch_aspace_regcache (ptid_t ptid, struct gdbarch *gdbarch,
 409                                    struct address_space *aspace);
 410
 411   friend void
 412   registers_changed_ptid (ptid_t ptid);
 413 };
 414
 415 class readonly_detached_regcache : public readable_regcache
 416 {
 417 public:
 418   readonly_detached_regcache (regcache &src);
 419
 420   /* Create a readonly regcache by getting contents from COOKED_READ.  */
 421
 422   readonly_detached_regcache (gdbarch *gdbarch, register_read_ftype cooked_read)
 423     : readable_regcache (gdbarch, true)
 424   {
 425     save (cooked_read);
 426   }
 427
 428   DISABLE_COPY_AND_ASSIGN (readonly_detached_regcache);
 429
 430   void raw_update (int regnum) override
 431   {}
 432 };
 433
 434 extern void registers_changed (void);
 435 extern void registers_changed_ptid (ptid_t);
 436
 437 /* Indicate that registers of THREAD may have changed, so invalidate
 438    the cache.  */
 439 extern void registers_changed_thread (thread_info *thread);
 440
 441 /* An abstract base class for register dump.  */
 442
 443 class register_dump
 444 {
 445 public:
 446   void dump (ui_file *file);
 447   virtual ~register_dump () = default;
 448
 449 protected:
 450   register_dump (gdbarch *arch)
 451     : m_gdbarch (arch)
 452   {}
 453
 454   /* Dump the register REGNUM contents.  If REGNUM is -1, print the
 455      header.  */
 456   virtual void dump_reg (ui_file *file, int regnum) = 0;
 457
 458   gdbarch *m_gdbarch;
 459 };
 460
 461 #endif /* REGCACHE_H */