1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
@section a.out backends
@strong{Description}@*
BFD supports a number of different flavours of a.out format,
though the major differences are only the sizes of the
structures on disk, and the shape of the relocation
information.
The support is split into a basic support file @file{aoutx.h}
and other files which derive functions from the base. One
derivation file is @file{aoutf1.h} (for a.out flavour 1), and
adds to the basic a.out functions support for sun3, sun4, 386
and 29k a.out files, to create a target jump vector for a
specific target.
This information is further split out into more specific files
for each machine, including @file{sunos.c} for sun3 and sun4,
@file{newsos3.c} for the Sony NEWS, and @file{demo64.c} for a
demonstration of a 64 bit a.out format.
The base file @file{aoutx.h} defines general mechanisms for
reading and writing records to and from disk and various
other methods which BFD requires. It is included by
@file{aout32.c} and @file{aout64.c} to form the names
@code{aout_32_swap_exec_header_in}, @code{aout_64_swap_exec_header_in}, etc.
As an example, this is what goes on to make the back end for a
sun4, from @file{aout32.c}:
@example
#define ARCH_SIZE 32
#include "aoutx.h"
@end example
Which exports names:
@example
...
aout_32_canonicalize_reloc
aout_32_find_nearest_line
aout_32_get_lineno
aout_32_get_reloc_upper_bound
...
@end example
from @file{sunos.c}:
@example
#define TARGET_NAME "a.out-sunos-big"
#define VECNAME sparc_aout_sunos_be_vec
#include "aoutf1.h"
@end example
requires all the names from @file{aout32.c}, and produces the jump vector
@example
sparc_aout_sunos_be_vec
@end example
The file @file{host-aout.c} is a special case. It is for a large set
of hosts that use ``more or less standard'' a.out files, and
for which cross-debugging is not interesting. It uses the
standard 32-bit a.out support routines, but determines the
file offsets and addresses of the text, data, and BSS
sections, the machine architecture and machine type, and the
entry point address, in a host-dependent manner. Once these
values have been determined, generic code is used to handle
the object file.
When porting it to run on a new system, you must supply:
@example
HOST_PAGE_SIZE
HOST_SEGMENT_SIZE
HOST_MACHINE_ARCH (optional)
HOST_MACHINE_MACHINE (optional)
HOST_TEXT_START_ADDR
HOST_STACK_END_ADDR
@end example
in the file @file{../include/sys/h-@var{XXX}.h} (for your host). These
values, plus the structures and macros defined in @file{a.out.h} on
your host system, will produce a BFD target that will access
ordinary a.out files on your host. To configure a new machine
to use @file{host-aout.c}, specify:
@example
TDEFAULTS = -DDEFAULT_VECTOR=host_aout_big_vec
TDEPFILES= host-aout.o trad-core.o
@end example
in the @file{config/@var{XXX}.mt} file, and modify @file{configure.ac}
to use the
@file{@var{XXX}.mt} file (by setting "@code{bfd_target=XXX}") when your
configuration is selected.
@subsection Relocations
@strong{Description}@*
The file @file{aoutx.h} provides for both the @emph{standard}
and @emph{extended} forms of a.out relocation records.
The standard records contain only an
address, a symbol index, and a type field. The extended records
(used on 29ks and sparcs) also have a full integer for an
addend.
@subsection Internal entry points
@strong{Description}@*
@file{aoutx.h} exports several routines for accessing the
contents of an a.out file, which are gathered and exported in
turn by various format specific files (eg sunos.c).
@findex aout_@var{size}_swap_exec_header_in
@subsubsection @code{aout_@var{size}_swap_exec_header_in}
@strong{Synopsis}
@example
void aout_@var{size}_swap_exec_header_in,
(bfd *abfd,
struct external_exec *bytes,
struct internal_exec *execp);
@end example
@strong{Description}@*
Swap the information in an executable header @var{raw_bytes} taken
from a raw byte stream memory image into the internal exec header
structure @var{execp}.
@findex aout_@var{size}_swap_exec_header_out
@subsubsection @code{aout_@var{size}_swap_exec_header_out}
@strong{Synopsis}
@example
void aout_@var{size}_swap_exec_header_out
(bfd *abfd,
struct internal_exec *execp,
struct external_exec *raw_bytes);
@end example
@strong{Description}@*
Swap the information in an internal exec header structure
@var{execp} into the buffer @var{raw_bytes} ready for writing to disk.
@findex aout_@var{size}_some_aout_object_p
@subsubsection @code{aout_@var{size}_some_aout_object_p}
@strong{Synopsis}
@example
const bfd_target *aout_@var{size}_some_aout_object_p
(bfd *abfd,
struct internal_exec *execp,
const bfd_target *(*callback_to_real_object_p) (bfd *));
@end example
@strong{Description}@*
Some a.out variant thinks that the file open in @var{abfd}
checking is an a.out file. Do some more checking, and set up
for access if it really is. Call back to the calling
environment's "finish up" function just before returning, to
handle any last-minute setup.
@findex aout_@var{size}_mkobject
@subsubsection @code{aout_@var{size}_mkobject}
@strong{Synopsis}
@example
bfd_boolean aout_@var{size}_mkobject, (bfd *abfd);
@end example
@strong{Description}@*
Initialize BFD @var{abfd} for use with a.out files.
@findex aout_@var{size}_machine_type
@subsubsection @code{aout_@var{size}_machine_type}
@strong{Synopsis}
@example
enum machine_type aout_@var{size}_machine_type
(enum bfd_architecture arch,
unsigned long machine,
bfd_boolean *unknown);
@end example
@strong{Description}@*
Keep track of machine architecture and machine type for
a.out's. Return the @code{machine_type} for a particular
architecture and machine, or @code{M_UNKNOWN} if that exact architecture
and machine can't be represented in a.out format.
If the architecture is understood, machine type 0 (default)
is always understood.
@findex aout_@var{size}_set_arch_mach
@subsubsection @code{aout_@var{size}_set_arch_mach}
@strong{Synopsis}
@example
bfd_boolean aout_@var{size}_set_arch_mach,
(bfd *,
enum bfd_architecture arch,
unsigned long machine);
@end example
@strong{Description}@*
Set the architecture and the machine of the BFD @var{abfd} to the
values @var{arch} and @var{machine}. Verify that @var{abfd}'s format
can support the architecture required.
@findex aout_@var{size}_new_section_hook
@subsubsection @code{aout_@var{size}_new_section_hook}
@strong{Synopsis}
@example
bfd_boolean aout_@var{size}_new_section_hook,
(bfd *abfd,
asection *newsect);
@end example
@strong{Description}@*
Called by the BFD in response to a @code{bfd_make_section}
request.
|
