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
27struct 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
35struct trad_frame_cache *
36trad_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
51struct trad_frame_saved_reg *
52trad_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
67enum { REG_VALUE = -1, REG_UNKNOWN = -2 };
68
69int
70trad_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
75int
76trad_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
82int
83trad_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
90void
91trad_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
100void
101trad_frame_set_reg_realreg (struct trad_frame_cache *this_trad_cache,
102			    int regnum, int realreg)
103{
104  this_trad_cache->prev_regs[regnum].realreg = realreg;
105  this_trad_cache->prev_regs[regnum].addr = -1;
106}
107
108void
109trad_frame_set_reg_addr (struct trad_frame_cache *this_trad_cache,
110			 int regnum, CORE_ADDR addr)
111{
112  this_trad_cache->prev_regs[regnum].addr = addr;
113}
114
115void
116trad_frame_set_unknown (struct trad_frame_saved_reg this_saved_regs[],
117			int regnum)
118{
119  /* Make the REALREG invalid, indicating that the value is not known.  */
120  this_saved_regs[regnum].realreg = REG_UNKNOWN;
121  this_saved_regs[regnum].addr = -1;
122}
123
124void
125trad_frame_get_prev_register (struct frame_info *next_frame,
126			      struct trad_frame_saved_reg this_saved_regs[],
127			      int regnum, int *optimizedp,
128			      enum lval_type *lvalp, CORE_ADDR *addrp,
129			      int *realregp, void *bufferp)
130{
131  struct gdbarch *gdbarch = get_frame_arch (next_frame);
132  if (trad_frame_addr_p (this_saved_regs, regnum))
133    {
134      /* The register was saved in memory.  */
135      *optimizedp = 0;
136      *lvalp = lval_memory;
137      *addrp = this_saved_regs[regnum].addr;
138      *realregp = -1;
139      if (bufferp != NULL)
140	{
141	  /* Read the value in from memory.  */
142	  get_frame_memory (next_frame, this_saved_regs[regnum].addr, bufferp,
143			    register_size (gdbarch, regnum));
144	}
145    }
146  else if (trad_frame_realreg_p (this_saved_regs, regnum))
147    {
148      /* Ask the next frame to return the value of the register.  */
149      frame_register_unwind (next_frame, this_saved_regs[regnum].realreg,
150			     optimizedp, lvalp, addrp, realregp, bufferp);
151    }
152  else if (trad_frame_value_p (this_saved_regs, regnum))
153    {
154      /* The register's value is available.  */
155      *optimizedp = 0;
156      *lvalp = not_lval;
157      *addrp = 0;
158      *realregp = -1;
159      if (bufferp != NULL)
160	store_unsigned_integer (bufferp, register_size (gdbarch, regnum),
161				this_saved_regs[regnum].addr);
162    }
163  else
164    {
165      error ("Register %s not available",
166	     gdbarch_register_name (gdbarch, regnum));
167    }
168}
169
170void
171trad_frame_get_register (struct trad_frame_cache *this_trad_cache,
172			 struct frame_info *next_frame,
173			 int regnum, int *optimizedp,
174			 enum lval_type *lvalp, CORE_ADDR *addrp,
175			 int *realregp, void *bufferp)
176{
177  trad_frame_get_prev_register (next_frame, this_trad_cache->prev_regs,
178				regnum, optimizedp, lvalp, addrp, realregp,
179				bufferp);
180}
181
182void
183trad_frame_set_id (struct trad_frame_cache *this_trad_cache,
184		   struct frame_id this_id)
185{
186  this_trad_cache->this_id = this_id;
187}
188
189void
190trad_frame_get_id (struct trad_frame_cache *this_trad_cache,
191		   struct frame_id *this_id)
192{
193  (*this_id) = this_trad_cache->this_id;
194}
195
196void
197trad_frame_set_this_base (struct trad_frame_cache *this_trad_cache,
198			  CORE_ADDR this_base)
199{
200  this_trad_cache->this_base = this_base;
201}
202
203CORE_ADDR
204trad_frame_get_this_base (struct trad_frame_cache *this_trad_cache)
205{
206  return this_trad_cache->this_base;
207}
208