gdb/trad-frame.c

   1 /* Traditional frame unwind support, for GDB the GNU Debugger.
   2
   3    Copyright (C) 2003-2017 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 struct trad_frame_saved_reg *
  47 trad_frame_alloc_saved_regs (struct gdbarch *gdbarch)
  48 {
  49   int regnum;
  50   int numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
  51   struct trad_frame_saved_reg *this_saved_regs
  52     = FRAME_OBSTACK_CALLOC (numregs, struct trad_frame_saved_reg);
  53
  54   for (regnum = 0; regnum < numregs; regnum++)
  55     {
  56       this_saved_regs[regnum].realreg = regnum;
  57       this_saved_regs[regnum].addr = -1;
  58     }
  59   return this_saved_regs;
  60 }
  61
  62 /* A traditional frame is unwound by analysing the function prologue
  63    and using the information gathered to track registers.  For
  64    non-optimized frames, the technique is reliable (just need to check
  65    for all potential instruction sequences).  */
  66
  67 struct trad_frame_saved_reg *
  68 trad_frame_alloc_saved_regs (struct frame_info *this_frame)
  69 {
  70   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  71
  72   return trad_frame_alloc_saved_regs (gdbarch);
  73 }
  74
  75 enum { TF_REG_VALUE = -1, TF_REG_UNKNOWN = -2 };
  76
  77 int
  78 trad_frame_value_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  79 {
  80   return (this_saved_regs[regnum].realreg == TF_REG_VALUE);
  81 }
  82
  83 int
  84 trad_frame_addr_p (struct trad_frame_saved_reg this_saved_regs[], int regnum)
  85 {
  86   return (this_saved_regs[regnum].realreg >= 0
  87           && this_saved_regs[regnum].addr != -1);
  88 }
  89
  90 int
  91 trad_frame_realreg_p (struct trad_frame_saved_reg this_saved_regs[],
  92                       int regnum)
  93 {
  94   return (this_saved_regs[regnum].realreg >= 0
  95           && this_saved_regs[regnum].addr == -1);
  96 }
  97
  98 void
  99 trad_frame_set_value (struct trad_frame_saved_reg this_saved_regs[],
 100                       int regnum, LONGEST val)
 101 {
 102   /* Make the REALREG invalid, indicating that the ADDR contains the
 103      register's value.  */
 104   this_saved_regs[regnum].realreg = TF_REG_VALUE;
 105   this_saved_regs[regnum].addr = val;
 106 }
 107
 108 void
 109 trad_frame_set_reg_value (struct trad_frame_cache *this_trad_cache,
 110                           int regnum, LONGEST val)
 111 {
 112   /* External interface for users of trad_frame_cache
 113      (who cannot access the prev_regs object directly).  */
 114   trad_frame_set_value (this_trad_cache->prev_regs, regnum, val);
 115 }
 116
 117 void
 118 trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
 119                             int regnum, int realreg)
 120 {
 121   this_trad_cache->prev_regs[regnum].realreg = realreg;
 122   this_trad_cache->prev_regs[regnum].addr = -1;
 123 }
 124
 125 void
 126 trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
 127                          int regnum, CORE_ADDR addr)
 128 {
 129   this_trad_cache->prev_regs[regnum].addr = addr;
 130 }
 131
 132 void
 133 trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
 134                         int regnum)
 135 {
 136   /* Make the REALREG invalid, indicating that the value is not known.  */
 137   this_saved_regs[regnum].realreg = TF_REG_UNKNOWN;
 138   this_saved_regs[regnum].addr = -1;
 139 }
 140
 141 struct value *
 142 trad_frame_get_prev_register (struct frame_info *this_frame,
 143                               struct trad_frame_saved_reg this_saved_regs[],
 144                               int regnum)
 145 {
 146   if (trad_frame_addr_p (this_saved_regs, regnum))
 147     /* The register was saved in memory.  */
 148     return frame_unwind_got_memory (this_frame, regnum,
 149                                     this_saved_regs[regnum].addr);
 150   else if (trad_frame_realreg_p (this_saved_regs, regnum))
 151     return frame_unwind_got_register (this_frame, regnum,
 152                                       this_saved_regs[regnum].realreg);
 153   else if (trad_frame_value_p (this_saved_regs, regnum))
 154     /* The register's value is available.  */
 155     return frame_unwind_got_constant (this_frame, regnum,
 156                                       this_saved_regs[regnum].addr);
 157   else
 158     return frame_unwind_got_optimized (this_frame, regnum);
 159 }
 160
 161 struct value *
 162 trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
 163                          struct frame_info *this_frame,
 164                          int regnum)
 165 {
 166   return trad_frame_get_prev_register (this_frame, this_trad_cache->prev_regs,
 167                                        regnum);
 168 }
 169
 170 void
 171 trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
 172                    struct frame_id this_id)
 173 {
 174   this_trad_cache->this_id = this_id;
 175 }
 176
 177 void
 178 trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
 179                    struct frame_id *this_id)
 180 {
 181   (*this_id) = this_trad_cache->this_id;
 182 }
 183
 184 void
 185 trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
 186                           CORE_ADDR this_base)
 187 {
 188   this_trad_cache->this_base = this_base;
 189 }
 190
 191 CORE_ADDR
 192 trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
 193 {
 194   return this_trad_cache->this_base;
 195 }