1/* Frame unwinder for frames with DWARF Call Frame Information.
2
3   Copyright 2003, 2004 Free Software Foundation, Inc.
4
5   Contributed by Mark Kettenis.
6
7   This file is part of GDB.
8
9   This program is free software; you can redistribute it and/or modify
10   it under the terms of the GNU General Public License as published by
11   the Free Software Foundation; either version 2 of the License, or
12   (at your option) any later version.
13
14   This program is distributed in the hope that it will be useful,
15   but WITHOUT ANY WARRANTY; without even the implied warranty of
16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17   GNU General Public License for more details.
18
19   You should have received a copy of the GNU General Public License
20   along with this program; if not, write to the Free Software
21   Foundation, Inc., 59 Temple Place - Suite 330,
22   Boston, MA 02111-1307, USA.  */
23
24#ifndef DWARF2_FRAME_H
25#define DWARF2_FRAME_H 1
26
27struct gdbarch;
28struct objfile;
29struct frame_info;
30
31/* Register rule.  */
32
33enum dwarf2_frame_reg_rule
34{
35  /* Make certain that 0 maps onto the correct enum value; the
36     corresponding structure is being initialized using memset zero.
37     This indicates that CFI didn't provide any information at all
38     about a register, leaving how to obtain its value totally
39     unspecified.  */
40  DWARF2_FRAME_REG_UNSPECIFIED = 0,
41
42  /* The term "undefined" comes from the DWARF2 CFI spec which this
43     code is moddeling; it indicates that the register's value is
44     "undefined".  GCC uses the less formal term "unsaved".  Its
45     definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
46     The failure to differentiate the two helps explain a few problems
47     with the CFI generated by GCC.  */
48  DWARF2_FRAME_REG_UNDEFINED,
49  DWARF2_FRAME_REG_SAVED_OFFSET,
50  DWARF2_FRAME_REG_SAVED_REG,
51  DWARF2_FRAME_REG_SAVED_EXP,
52  DWARF2_FRAME_REG_SAME_VALUE,
53
54  /* These aren't defined by the DWARF2 CFI specification, but are
55     used internally by GDB.  */
56  DWARF2_FRAME_REG_RA,		/* Return Address.  */
57  DWARF2_FRAME_REG_CFA		/* Call Frame Address.  */
58};
59
60/* Register state.  */
61
62struct dwarf2_frame_state_reg
63{
64  /* Each register save state can be described in terms of a CFA slot,
65     another register, or a location expression.  */
66  union {
67    LONGEST offset;
68    ULONGEST reg;
69    unsigned char *exp;
70  } loc;
71  ULONGEST exp_len;
72  enum dwarf2_frame_reg_rule how;
73};
74
75/* Set the architecture-specific register state initialization
76   function for GDBARCH to INIT_REG.  */
77
78extern void dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
79				       void (*init_reg) (struct gdbarch *, int,
80					     struct dwarf2_frame_state_reg *));
81
82/* Return the frame unwind methods for the function that contains PC,
83   or NULL if it can't be handled by DWARF CFI frame unwinder.  */
84
85extern const struct frame_unwind *
86  dwarf2_frame_sniffer (struct frame_info *next_frame);
87
88/* Return the frame base methods for the function that contains PC, or
89   NULL if it can't be handled by the DWARF CFI frame unwinder.  */
90
91extern const struct frame_base *
92  dwarf2_frame_base_sniffer (struct frame_info *next_frame);
93
94/* Register the DWARF CFI for OBJFILE.  */
95
96void dwarf2_frame_build_info (struct objfile *objfile);
97
98#endif /* dwarf2-frame.h */
99