gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright 2003, 2004 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 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_addr (struct trad_frame_cache *this_trad_cache,
 102                          int regnum, CORE_ADDR addr)
 103 {
 104   this_trad_cache->prev_regs[regnum].addr = addr;
 105 }
 106
 107 void
 108 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 109                         int regnum)
 110 {
 111   /* Make the REALREG invalid, indicating that the value is not known.  */
 112   this_saved_regs[regnum].realreg = REG_UNKNOWN;
 113   this_saved_regs[regnum].addr = -1;
 114 }
 115
 116 void
 117 trad_frame_get_prev_register (struct frame_info *next_frame,
 118                               struct trad_frame_saved_reg this_saved_regs[],
 119                               int regnum, int *optimizedp,
 120                               enum lval_type *lvalp, CORE_ADDR *addrp,
 121                               int *realregp, void *bufferp)
 122 {
 123   struct gdbarch *gdbarch = get_frame_arch (next_frame);
 124   if (trad_frame_addr_p (this_saved_regs, regnum))
 125     {
 126       /* The register was saved in memory.  */
 127       *optimizedp = 0;
 128       *lvalp = lval_memory;
 129       *addrp = this_saved_regs[regnum].addr;
 130       *realregp = -1;
 131       if (bufferp != NULL)
 132         {
 133           /* Read the value in from memory.  */
 134           get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
 135                             register_size (gdbarch, regnum));
 136         }
 137     }
 138   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 139     {
 140       /* Ask the next frame to return the value of the register.  */
 141       frame_register_unwind (next_frame, this_saved_regs[regnum].realreg,
 142                              optimizedp, lvalp, addrp, realregp, bufferp);
 143     }
 144   else if (trad_frame_value_p (this_saved_regs, regnum))
 145     {
 146       /* The register's value is available.  */
 147       *optimizedp = 0;
 148       *lvalp = not_lval;
 149       *addrp = 0;
 150       *realregp = -1;
 151       if (bufferp != NULL)
 152         store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
 153                                 this_saved_regs[regnum].addr);
 154     }
 155   else
 156     {
 157       error ("Register %s not available",
 158              gdbarch_register_name (gdbarch, regnum));
 159     }
 160 }
 161
 162 void
 163 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 164                          struct frame_info *next_frame,
 165                          int regnum, int *optimizedp,
 166                          enum lval_type *lvalp, CORE_ADDR *addrp,
 167                          int *realregp, void *bufferp)
 168 {
 169   trad_frame_get_prev_register (next_frame, this_trad_cache->prev_regs,
 170                                 regnum, optimizedp, lvalp, addrp, realregp,
 171                                 bufferp);
 172 }
 173
 174 void
 175 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 176                    struct frame_id this_id)
 177 {
 178   this_trad_cache->this_id = this_id;
 179 }
 180
 181 void
 182 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 183                    struct frame_id *this_id)
 184 {
 185   (*this_id) = this_trad_cache->this_id;
 186 }