gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright (C) 2003, 2004, 2007 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 #include "defs.h"
  21 #include "frame.h"
  22 #include "trad-frame.h"
  23 #include "regcache.h"
  24
  25 struct trad_frame_cache
  26 {
  27   struct frame_info *next_frame;
  28   CORE_ADDR this_base;
  29   struct trad_frame_saved_reg *prev_regs;
  30   struct frame_id this_id;
  31 };
  32
  33 struct trad_frame_cache *
  34 trad_frame_cache_zalloc (struct frame_info *next_frame)
  35 {
  36   struct trad_frame_cache *this_trad_cache;
  37
  38   this_trad_cache = FRAME_OBSTACK_ZALLOC (struct trad_frame_cache);
  39   this_trad_cache->prev_regs = trad_frame_alloc_saved_regs (next_frame);
  40   this_trad_cache->next_frame = next_frame;
  41   return this_trad_cache;
  42 }
  43
  44 /* A traditional frame is unwound by analysing the function prologue
  45    and using the information gathered to track registers.  For
  46    non-optimized frames, the technique is reliable (just need to check
  47    for all potential instruction sequences).  */
  48
  49 struct trad_frame_saved_reg *
  50 trad_frame_alloc_saved_regs (struct frame_info *next_frame)
  51 {
  52   int regnum;
  53   struct gdbarch *gdbarch = get_frame_arch (next_frame);
  54   int numregs = gdbarch_num_regs (current_gdbarch)
  55                 + gdbarch_num_pseudo_regs (current_gdbarch);
  56   struct trad_frame_saved_reg *this_saved_regs
  57     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  58   for (regnum = 0; regnum < numregs; regnum++)
  59     {
  60       this_saved_regs[regnum].realreg = regnum;
  61       this_saved_regs[regnum].addr = -1;
  62     }
  63   return this_saved_regs;
  64 }
  65
  66 enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
  67
  68 int
  69 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  70 {
  71   return (this_saved_regs[regnum].realreg == REG_VALUE);
  72 }
  73
  74 int
  75 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  76 {
  77   return (this_saved_regs[regnum].realreg >= 0
  78           && this_saved_regs[regnum].addr != -1);
  79 }
  80
  81 int
  82 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  83                       int regnum)
  84 {
  85   return (this_saved_regs[regnum].realreg >= 0
  86           && this_saved_regs[regnum].addr == -1);
  87 }
  88
  89 void
  90 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
  91                       int regnum, LONGEST val)
  92 {
  93   /* Make the REALREG invalid, indicating that the ADDR contains the
  94      register's value.  */
  95   this_saved_regs[regnum].realreg = REG_VALUE;
  96   this_saved_regs[regnum].addr = val;
  97 }
  98
  99 void
 100 trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
 101                           int regnum, LONGEST val)
 102 {
 103   /* External interface for users of trad_frame_cache
 104      (who cannot access the prev_regs object directly).  */
 105   trad_frame_set_value (this_trad_cache->prev_regs, regnum, val);
 106 }
 107
 108 void
 109 trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
 110                             int regnum, int realreg)
 111 {
 112   this_trad_cache->prev_regs[regnum].realreg = realreg;
 113   this_trad_cache->prev_regs[regnum].addr = -1;
 114 }
 115
 116 void
 117 trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
 118                          int regnum, CORE_ADDR addr)
 119 {
 120   this_trad_cache->prev_regs[regnum].addr = addr;
 121 }
 122
 123 void
 124 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 125                         int regnum)
 126 {
 127   /* Make the REALREG invalid, indicating that the value is not known.  */
 128   this_saved_regs[regnum].realreg = REG_UNKNOWN;
 129   this_saved_regs[regnum].addr = -1;
 130 }
 131
 132 void
 133 trad_frame_get_prev_register (struct frame_info *next_frame,
 134                               struct trad_frame_saved_reg this_saved_regs[],
 135                               int regnum, int *optimizedp,
 136                               enum lval_type *lvalp, CORE_ADDR *addrp,
 137                               int *realregp, gdb_byte *bufferp)
 138 {
 139   struct gdbarch *gdbarch = get_frame_arch (next_frame);
 140   if (trad_frame_addr_p (this_saved_regs, regnum))
 141     {
 142       /* The register was saved in memory.  */
 143       *optimizedp = 0;
 144       *lvalp = lval_memory;
 145       *addrp = this_saved_regs[regnum].addr;
 146       *realregp = -1;
 147       if (bufferp != NULL)
 148         {
 149           /* Read the value in from memory.  */
 150           get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
 151                             register_size (gdbarch, regnum));
 152         }
 153     }
 154   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 155     {
 156       *optimizedp = 0;
 157       *lvalp = lval_register;
 158       *addrp = 0;
 159       *realregp = this_saved_regs[regnum].realreg;
 160       /* Ask the next frame to return the value of the register.  */
 161       if (bufferp)
 162         frame_unwind_register (next_frame, (*realregp), bufferp);
 163     }
 164   else if (trad_frame_value_p (this_saved_regs, regnum))
 165     {
 166       /* The register's value is available.  */
 167       *optimizedp = 0;
 168       *lvalp = not_lval;
 169       *addrp = 0;
 170       *realregp = -1;
 171       if (bufferp != NULL)
 172         store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
 173                                 this_saved_regs[regnum].addr);
 174     }
 175   else
 176     {
 177       error (_("Register %s not available"),
 178              gdbarch_register_name (gdbarch, regnum));
 179     }
 180 }
 181
 182 void
 183 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 184                          struct frame_info *next_frame,
 185                          int regnum, int *optimizedp,
 186                          enum lval_type *lvalp, CORE_ADDR *addrp,
 187                          int *realregp, gdb_byte *bufferp)
 188 {
 189   trad_frame_get_prev_register (next_frame, this_trad_cache->prev_regs,
 190                                 regnum, optimizedp, lvalp, addrp, realregp,
 191                                 bufferp);
 192 }
 193
 194 void
 195 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 196                    struct frame_id this_id)
 197 {
 198   this_trad_cache->this_id = this_id;
 199 }
 200
 201 void
 202 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 203                    struct frame_id *this_id)
 204 {
 205   (*this_id) = this_trad_cache->this_id;
 206 }
 207
 208 void
 209 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 210                           CORE_ADDR this_base)
 211 {
 212   this_trad_cache->this_base = this_base;
 213 }
 214
 215 CORE_ADDR
 216 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 217 {
 218   return this_trad_cache->this_base;
 219 }