gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008 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 (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
  55   struct trad_frame_saved_reg *this_saved_regs
  56     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  57   for (regnum = 0; regnum < numregs; regnum++)
  58     {
  59       this_saved_regs[regnum].realreg = regnum;
  60       this_saved_regs[regnum].addr = -1;
  61     }
  62   return this_saved_regs;
  63 }
  64
  65 enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
  66
  67 int
  68 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  69 {
  70   return (this_saved_regs[regnum].realreg == REG_VALUE);
  71 }
  72
  73 int
  74 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  75 {
  76   return (this_saved_regs[regnum].realreg >= 0
  77           && this_saved_regs[regnum].addr != -1);
  78 }
  79
  80 int
  81 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  82                       int regnum)
  83 {
  84   return (this_saved_regs[regnum].realreg >= 0
  85           && this_saved_regs[regnum].addr == -1);
  86 }
  87
  88 void
  89 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
  90                       int regnum, LONGEST val)
  91 {
  92   /* Make the REALREG invalid, indicating that the ADDR contains the
  93      register's value.  */
  94   this_saved_regs[regnum].realreg = REG_VALUE;
  95   this_saved_regs[regnum].addr = val;
  96 }
  97
  98 void
  99 trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
 100                           int regnum, LONGEST val)
 101 {
 102   /* External interface for users of trad_frame_cache
 103      (who cannot access the prev_regs object directly).  */
 104   trad_frame_set_value (this_trad_cache->prev_regs, regnum, val);
 105 }
 106
 107 void
 108 trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
 109                             int regnum, int realreg)
 110 {
 111   this_trad_cache->prev_regs[regnum].realreg = realreg;
 112   this_trad_cache->prev_regs[regnum].addr = -1;
 113 }
 114
 115 void
 116 trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
 117                          int regnum, CORE_ADDR addr)
 118 {
 119   this_trad_cache->prev_regs[regnum].addr = addr;
 120 }
 121
 122 void
 123 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 124                         int regnum)
 125 {
 126   /* Make the REALREG invalid, indicating that the value is not known.  */
 127   this_saved_regs[regnum].realreg = REG_UNKNOWN;
 128   this_saved_regs[regnum].addr = -1;
 129 }
 130
 131 void
 132 trad_frame_get_prev_register (struct frame_info *next_frame,
 133                               struct trad_frame_saved_reg this_saved_regs[],
 134                               int regnum, int *optimizedp,
 135                               enum lval_type *lvalp, CORE_ADDR *addrp,
 136                               int *realregp, gdb_byte *bufferp)
 137 {
 138   struct gdbarch *gdbarch = get_frame_arch (next_frame);
 139   if (trad_frame_addr_p (this_saved_regs, regnum))
 140     {
 141       /* The register was saved in memory.  */
 142       *optimizedp = 0;
 143       *lvalp = lval_memory;
 144       *addrp = this_saved_regs[regnum].addr;
 145       *realregp = -1;
 146       if (bufferp != NULL)
 147         {
 148           /* Read the value in from memory.  */
 149           get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
 150                             register_size (gdbarch, regnum));
 151         }
 152     }
 153   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 154     {
 155       *optimizedp = 0;
 156       *lvalp = lval_register;
 157       *addrp = 0;
 158       *realregp = this_saved_regs[regnum].realreg;
 159       /* Ask the next frame to return the value of the register.  */
 160       if (bufferp)
 161         frame_unwind_register (next_frame, (*realregp), bufferp);
 162     }
 163   else if (trad_frame_value_p (this_saved_regs, regnum))
 164     {
 165       /* The register's value is available.  */
 166       *optimizedp = 0;
 167       *lvalp = not_lval;
 168       *addrp = 0;
 169       *realregp = -1;
 170       if (bufferp != NULL)
 171         store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
 172                                 this_saved_regs[regnum].addr);
 173     }
 174   else
 175     {
 176       error (_("Register %s not available"),
 177              gdbarch_register_name (gdbarch, regnum));
 178     }
 179 }
 180
 181 void
 182 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 183                          struct frame_info *next_frame,
 184                          int regnum, int *optimizedp,
 185                          enum lval_type *lvalp, CORE_ADDR *addrp,
 186                          int *realregp, gdb_byte *bufferp)
 187 {
 188   trad_frame_get_prev_register (next_frame, this_trad_cache->prev_regs,
 189                                 regnum, optimizedp, lvalp, addrp, realregp,
 190                                 bufferp);
 191 }
 192
 193 void
 194 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 195                    struct frame_id this_id)
 196 {
 197   this_trad_cache->this_id = this_id;
 198 }
 199
 200 void
 201 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 202                    struct frame_id *this_id)
 203 {
 204   (*this_id) = this_trad_cache->this_id;
 205 }
 206
 207 void
 208 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 209                           CORE_ADDR this_base)
 210 {
 211   this_trad_cache->this_base = this_base;
 212 }
 213
 214 CORE_ADDR
 215 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 216 {
 217   return this_trad_cache->this_base;
 218 }