gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright (C) 2003, 2004, 2007, 2008, 2009 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 #include "frame-unwind.h"
  25 #include "value.h"
  26
  27 struct trad_frame_cache
  28 {
  29   struct frame_info *this_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 *this_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 (this_frame);
  42   this_trad_cache->this_frame = this_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 *this_frame)
  53 {
  54   int regnum;
  55   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  56   int numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
  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 struct value *
 134 trad_frame_get_prev_register (struct frame_info *this_frame,
 135                               struct trad_frame_saved_reg this_saved_regs[],
 136                               int regnum)
 137 {
 138   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 139   if (trad_frame_addr_p (this_saved_regs, regnum))
 140     /* The register was saved in memory.  */
 141     return frame_unwind_got_memory (this_frame, regnum,
 142                                     this_saved_regs[regnum].addr);
 143   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 144     return frame_unwind_got_register (this_frame, regnum,
 145                                       this_saved_regs[regnum].realreg);
 146   else if (trad_frame_value_p (this_saved_regs, regnum))
 147     /* The register's value is available.  */
 148     return frame_unwind_got_constant (this_frame, regnum,
 149                                       this_saved_regs[regnum].addr);
 150   else
 151     return frame_unwind_got_optimized (this_frame, regnum);
 152 }
 153
 154 struct value *
 155 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 156                          struct frame_info *this_frame,
 157                          int regnum)
 158 {
 159   return trad_frame_get_prev_register (this_frame, this_trad_cache->prev_regs,
 160                                        regnum);
 161 }
 162
 163 void
 164 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 165                    struct frame_id this_id)
 166 {
 167   this_trad_cache->this_id = this_id;
 168 }
 169
 170 void
 171 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 172                    struct frame_id *this_id)
 173 {
 174   (*this_id) = this_trad_cache->this_id;
 175 }
 176
 177 void
 178 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 179                           CORE_ADDR this_base)
 180 {
 181   this_trad_cache->this_base = this_base;
 182 }
 183
 184 CORE_ADDR
 185 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 186 {
 187   return this_trad_cache->this_base;
 188 }