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
32struct trad_frame_saved_reg *
33trad_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
48enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
49
50int
51trad_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
56int
57trad_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
63int
64trad_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
71void
72trad_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
81void
82trad_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
90void
91trad_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}
135