gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "frame.h"
  23 #include "trad-frame.h"
  24 #include "regcache.h"
  25 #include "frame-unwind.h"
  26 #include "value.h"
  27
  28 struct trad_frame_cache
  29 {
  30   struct frame_info *this_frame;
  31   CORE_ADDR this_base;
  32   struct trad_frame_saved_reg *prev_regs;
  33   struct frame_id this_id;
  34 };
  35
  36 struct trad_frame_cache *
  37 trad_frame_cache_zalloc (struct frame_info *this_frame)
  38 {
  39   struct trad_frame_cache *this_trad_cache;
  40
  41   this_trad_cache = FRAME_OBSTACK_ZALLOC (struct trad_frame_cache);
  42   this_trad_cache->prev_regs = trad_frame_alloc_saved_regs (this_frame);
  43   this_trad_cache->this_frame = this_frame;
  44   return this_trad_cache;
  45 }
  46
  47 /* A traditional frame is unwound by analysing the function prologue
  48    and using the information gathered to track registers.  For
  49    non-optimized frames, the technique is reliable (just need to check
  50    for all potential instruction sequences).  */
  51
  52 struct trad_frame_saved_reg *
  53 trad_frame_alloc_saved_regs (struct frame_info *this_frame)
  54 {
  55   int regnum;
  56   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  57   int numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
  58   struct trad_frame_saved_reg *this_saved_regs
  59     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  60
  61   for (regnum = 0; regnum < numregs; regnum++)
  62     {
  63       this_saved_regs[regnum].realreg = regnum;
  64       this_saved_regs[regnum].addr = -1;
  65     }
  66   return this_saved_regs;
  67 }
  68
  69 enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
  70
  71 int
  72 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  73 {
  74   return (this_saved_regs[regnum].realreg == REG_VALUE);
  75 }
  76
  77 int
  78 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  79 {
  80   return (this_saved_regs[regnum].realreg >= 0
  81           && this_saved_regs[regnum].addr != -1);
  82 }
  83
  84 int
  85 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  86                       int regnum)
  87 {
  88   return (this_saved_regs[regnum].realreg >= 0
  89           && this_saved_regs[regnum].addr == -1);
  90 }
  91
  92 void
  93 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
  94                       int regnum, LONGEST val)
  95 {
  96   /* Make the REALREG invalid, indicating that the ADDR contains the
  97      register's value.  */
  98   this_saved_regs[regnum].realreg = REG_VALUE;
  99   this_saved_regs[regnum].addr = val;
 100 }
 101
 102 void
 103 trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
 104                           int regnum, LONGEST val)
 105 {
 106   /* External interface for users of trad_frame_cache
 107      (who cannot access the prev_regs object directly).  */
 108   trad_frame_set_value (this_trad_cache->prev_regs, regnum, val);
 109 }
 110
 111 void
 112 trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
 113                             int regnum, int realreg)
 114 {
 115   this_trad_cache->prev_regs[regnum].realreg = realreg;
 116   this_trad_cache->prev_regs[regnum].addr = -1;
 117 }
 118
 119 void
 120 trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
 121                          int regnum, CORE_ADDR addr)
 122 {
 123   this_trad_cache->prev_regs[regnum].addr = addr;
 124 }
 125
 126 void
 127 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 128                         int regnum)
 129 {
 130   /* Make the REALREG invalid, indicating that the value is not known.  */
 131   this_saved_regs[regnum].realreg = REG_UNKNOWN;
 132   this_saved_regs[regnum].addr = -1;
 133 }
 134
 135 struct value *
 136 trad_frame_get_prev_register (struct frame_info *this_frame,
 137                               struct trad_frame_saved_reg this_saved_regs[],
 138                               int regnum)
 139 {
 140   if (trad_frame_addr_p (this_saved_regs, regnum))
 141     /* The register was saved in memory.  */
 142     return frame_unwind_got_memory (this_frame, regnum,
 143                                     this_saved_regs[regnum].addr);
 144   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 145     return frame_unwind_got_register (this_frame, regnum,
 146                                       this_saved_regs[regnum].realreg);
 147   else if (trad_frame_value_p (this_saved_regs, regnum))
 148     /* The register's value is available.  */
 149     return frame_unwind_got_constant (this_frame, regnum,
 150                                       this_saved_regs[regnum].addr);
 151   else
 152     return frame_unwind_got_optimized (this_frame, regnum);
 153 }
 154
 155 struct value *
 156 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 157                          struct frame_info *this_frame,
 158                          int regnum)
 159 {
 160   return trad_frame_get_prev_register (this_frame, this_trad_cache->prev_regs,
 161                                        regnum);
 162 }
 163
 164 void
 165 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 166                    struct frame_id this_id)
 167 {
 168   this_trad_cache->this_id = this_id;
 169 }
 170
 171 void
 172 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 173                    struct frame_id *this_id)
 174 {
 175   (*this_id) = this_trad_cache->this_id;
 176 }
 177
 178 void
 179 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 180                           CORE_ADDR this_base)
 181 {
 182   this_trad_cache->this_base = this_base;
 183 }
 184
 185 CORE_ADDR
 186 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 187 {
 188   return this_trad_cache->this_base;
 189 }