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 2 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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "trad-frame.h"
  25 #include "regcache.h"
  26
  27 struct trad_frame_cache
  28 {
  29   struct frame_info *next_frame;
  30   CORE_ADDR this_base;
  31   struct trad_frame_saved_reg *prev_regs;
  32   struct frame_id this_id;
  33 };
  34
  35 struct trad_frame_cache *
  36 trad_frame_cache_zalloc (struct frame_info *next_frame)
  37 {
  38   struct trad_frame_cache *this_trad_cache;
  39
  40   this_trad_cache = FRAME_OBSTACK_ZALLOC (struct trad_frame_cache);
  41   this_trad_cache->prev_regs = trad_frame_alloc_saved_regs (next_frame);
  42   this_trad_cache->next_frame = next_frame;
  43   return this_trad_cache;
  44 }
  45
  46 /* A traditional frame is unwound by analysing the function prologue
  47    and using the information gathered to track registers.  For
  48    non-optimized frames, the technique is reliable (just need to check
  49    for all potential instruction sequences).  */
  50
  51 struct trad_frame_saved_reg *
  52 trad_frame_alloc_saved_regs (struct frame_info *next_frame)
  53 {
  54   int regnum;
  55   struct gdbarch *gdbarch = get_frame_arch (next_frame);
  56   int numregs = NUM_REGS + NUM_PSEUDO_REGS;
  57   struct trad_frame_saved_reg *this_saved_regs
  58     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  59   for (regnum = 0; regnum < numregs; regnum++)
  60     {
  61       this_saved_regs[regnum].realreg = regnum;
  62       this_saved_regs[regnum].addr = -1;
  63     }
  64   return this_saved_regs;
  65 }
  66
  67 enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
  68
  69 int
  70 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  71 {
  72   return (this_saved_regs[regnum].realreg == REG_VALUE);
  73 }
  74
  75 int
  76 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  77 {
  78   return (this_saved_regs[regnum].realreg >= 0
  79           && this_saved_regs[regnum].addr != -1);
  80 }
  81
  82 int
  83 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  84                       int regnum)
  85 {
  86   return (this_saved_regs[regnum].realreg >= 0
  87           && this_saved_regs[regnum].addr == -1);
  88 }
  89
  90 void
  91 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
  92                       int regnum, LONGEST val)
  93 {
  94   /* Make the REALREG invalid, indicating that the ADDR contains the
  95      register's value.  */
  96   this_saved_regs[regnum].realreg = REG_VALUE;
  97   this_saved_regs[regnum].addr = val;
  98 }
  99
 100 void
 101 trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
 102                           int regnum, LONGEST val)
 103 {
 104   /* External interface for users of trad_frame_cache
 105      (who cannot access the prev_regs object directly).  */
 106   trad_frame_set_value (this_trad_cache->prev_regs, regnum, val);
 107 }
 108
 109 void
 110 trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
 111                             int regnum, int realreg)
 112 {
 113   this_trad_cache->prev_regs[regnum].realreg = realreg;
 114   this_trad_cache->prev_regs[regnum].addr = -1;
 115 }
 116
 117 void
 118 trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
 119                          int regnum, CORE_ADDR addr)
 120 {
 121   this_trad_cache->prev_regs[regnum].addr = addr;
 122 }
 123
 124 void
 125 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 126                         int regnum)
 127 {
 128   /* Make the REALREG invalid, indicating that the value is not known.  */
 129   this_saved_regs[regnum].realreg = REG_UNKNOWN;
 130   this_saved_regs[regnum].addr = -1;
 131 }
 132
 133 void
 134 trad_frame_get_prev_register (struct frame_info *next_frame,
 135                               struct trad_frame_saved_reg this_saved_regs[],
 136                               int regnum, int *optimizedp,
 137                               enum lval_type *lvalp, CORE_ADDR *addrp,
 138                               int *realregp, gdb_byte *bufferp)
 139 {
 140   struct gdbarch *gdbarch = get_frame_arch (next_frame);
 141   if (trad_frame_addr_p (this_saved_regs, regnum))
 142     {
 143       /* The register was saved in memory.  */
 144       *optimizedp = 0;
 145       *lvalp = lval_memory;
 146       *addrp = this_saved_regs[regnum].addr;
 147       *realregp = -1;
 148       if (bufferp != NULL)
 149         {
 150           /* Read the value in from memory.  */
 151           get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
 152                             register_size (gdbarch, regnum));
 153         }
 154     }
 155   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 156     {
 157       *optimizedp = 0;
 158       *lvalp = lval_register;
 159       *addrp = 0;
 160       *realregp = this_saved_regs[regnum].realreg;
 161       /* Ask the next frame to return the value of the register.  */
 162       if (bufferp)
 163         frame_unwind_register (next_frame, (*realregp), bufferp);
 164     }
 165   else if (trad_frame_value_p (this_saved_regs, regnum))
 166     {
 167       /* The register's value is available.  */
 168       *optimizedp = 0;
 169       *lvalp = not_lval;
 170       *addrp = 0;
 171       *realregp = -1;
 172       if (bufferp != NULL)
 173         store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
 174                                 this_saved_regs[regnum].addr);
 175     }
 176   else
 177     {
 178       error (_("Register %s not available"),
 179              gdbarch_register_name (gdbarch, regnum));
 180     }
 181 }
 182
 183 void
 184 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 185                          struct frame_info *next_frame,
 186                          int regnum, int *optimizedp,
 187                          enum lval_type *lvalp, CORE_ADDR *addrp,
 188                          int *realregp, gdb_byte *bufferp)
 189 {
 190   trad_frame_get_prev_register (next_frame, this_trad_cache->prev_regs,
 191                                 regnum, optimizedp, lvalp, addrp, realregp,
 192                                 bufferp);
 193 }
 194
 195 void
 196 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 197                    struct frame_id this_id)
 198 {
 199   this_trad_cache->this_id = this_id;
 200 }
 201
 202 void
 203 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 204                    struct frame_id *this_id)
 205 {
 206   (*this_id) = this_trad_cache->this_id;
 207 }
 208
 209 void
 210 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 211                           CORE_ADDR this_base)
 212 {
 213   this_trad_cache->this_base = this_base;
 214 }
 215
 216 CORE_ADDR
 217 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 218 {
 219   return this_trad_cache->this_base;
 220 }