gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright 2003 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., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "frame.h"
  24 #include "trad-frame.h"
  25 #include "regcache.h"
  26
  27 /* A traditional frame is unwound by analysing the function prologue
  28    and using the information gathered to track registers.  For
  29    non-optimized frames, the technique is reliable (just need to check
  30    for all potential instruction sequences).  */
  31
  32 struct trad_frame_saved_reg *
  33 trad_frame_alloc_saved_regs (struct frame_info *next_frame)
  34 {
  35   int regnum;
  36   struct gdbarch *gdbarch = get_frame_arch (next_frame);
  37   int numregs = NUM_REGS + NUM_PSEUDO_REGS;
  38   struct trad_frame_saved_reg *this_saved_regs
  39     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  40   for (regnum = 0; regnum < numregs; regnum++)
  41     {
  42       this_saved_regs[regnum].realreg = regnum;
  43       this_saved_regs[regnum].addr = -1;
  44     }
  45   return this_saved_regs;
  46 }
  47
  48 enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
  49
  50 int
  51 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  52 {
  53   return (this_saved_regs[regnum].realreg == REG_VALUE);
  54 }
  55
  56 int
  57 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  58 {
  59   return (this_saved_regs[regnum].realreg >= 0
  60           && this_saved_regs[regnum].addr != -1);
  61 }
  62
  63 int
  64 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  65                       int regnum)
  66 {
  67   return (this_saved_regs[regnum].realreg >= 0
  68           && this_saved_regs[regnum].addr == -1);
  69 }
  70
  71 void
  72 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
  73                       int regnum, LONGEST val)
  74 {
  75   /* Make the REALREG invalid, indicating that the ADDR contains the
  76      register's value.  */
  77   this_saved_regs[regnum].realreg = REG_VALUE;
  78   this_saved_regs[regnum].addr = val;
  79 }
  80
  81 void
  82 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
  83                         int regnum)
  84 {
  85   /* Make the REALREG invalid, indicating that the value is not known.  */
  86   this_saved_regs[regnum].realreg = REG_UNKNOWN;
  87   this_saved_regs[regnum].addr = -1;
  88 }
  89
  90 void
  91 trad_frame_prev_register (struct frame_info *next_frame,
  92                           struct trad_frame_saved_reg this_saved_regs[],
  93                           int regnum, int *optimizedp,
  94                           enum lval_type *lvalp, CORE_ADDR *addrp,
  95                           int *realregp, void *bufferp)
  96 {
  97   struct gdbarch *gdbarch = get_frame_arch (next_frame);
  98   if (trad_frame_addr_p (this_saved_regs, regnum))
  99     {
 100       /* The register was saved in memory.  */
 101       *optimizedp = 0;
 102       *lvalp = lval_memory;
 103       *addrp = this_saved_regs[regnum].addr;
 104       *realregp = -1;
 105       if (bufferp != NULL)
 106         {
 107           /* Read the value in from memory.  */
 108           get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
 109                             register_size (gdbarch, regnum));
 110         }
 111     }
 112   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 113     {
 114       /* Ask the next frame to return the value of the register.  */
 115       frame_register_unwind (next_frame, this_saved_regs[regnum].realreg,
 116                              optimizedp, lvalp, addrp, realregp, bufferp);
 117     }
 118   else if (trad_frame_value_p (this_saved_regs, regnum))
 119     {
 120       /* The register's value is available.  */
 121       *optimizedp = 0;
 122       *lvalp = not_lval;
 123       *addrp = 0;
 124       *realregp = -1;
 125       if (bufferp != NULL)
 126         store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
 127                                 this_saved_regs[regnum].addr);
 128     }
 129   else
 130     {
 131       error ("Register %s not available",
 132              gdbarch_register_name (gdbarch, regnum));
 133     }
 134 }