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
214
215
216
217
218
219
|
/* cond.c - conditional assembly pseudo-ops, and .include
Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifndef lint
static char rcsid[] = "$Id: cond.c,v 1.1 1995/10/18 08:38:57 deraadt Exp $";
#endif
#include "as.h"
#include "obstack.h"
/* This is allocated to grow and shrink as .ifdef/.endif pairs are scanned. */
struct obstack cond_obstack;
struct file_line
{
char *file;
unsigned int line;
}; /* file_line */
/* This is what we push and pop. */
struct conditional_frame
{
struct file_line if_file_line; /* the source file & line number of the "if" */
struct file_line else_file_line; /* the source file & line of the "else" */
struct conditional_frame *previous_cframe;
int else_seen; /* have we seen an else yet? */
int ignoring; /* if we are currently ignoring input. */
int dead_tree; /* if a conditional at a higher level is ignoring input. */
}; /* conditional_frame */
static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
static struct conditional_frame *current_cframe = NULL;
void
s_ifdef (arg)
int arg;
{
register char *name; /* points to name of symbol */
register struct symbol *symbolP; /* Points to symbol */
struct conditional_frame cframe;
SKIP_WHITESPACE (); /* Leading whitespace is part of operand. */
name = input_line_pointer;
if (!is_name_beginner (*name))
{
as_bad ("invalid identifier for \".ifdef\"");
obstack_1grow (&cond_obstack, 0);
}
else
{
get_symbol_end ();
++input_line_pointer;
symbolP = symbol_find (name);
initialize_cframe (&cframe);
cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
current_cframe = (struct conditional_frame *) obstack_copy (&cond_obstack, &cframe, sizeof (cframe));
} /* if a valid identifyer name */
return;
} /* s_ifdef() */
void
s_if (arg)
int arg;
{
expressionS operand;
struct conditional_frame cframe;
SKIP_WHITESPACE (); /* Leading whitespace is part of operand. */
expression (&operand);
#ifdef notyet
if (operand.X_op != O_constant)
as_bad ("non-constant expression in \".if\" statement");
#else
if (operand.X_add_symbol != NULL || operand.X_subtract_symbol != NULL) {
as_bad("non-constant expression in \".if\" statement");
} /* bad condition */
#endif
/* If the above error is signaled, this will dispatch
using an undefined result. No big deal. */
initialize_cframe (&cframe);
cframe.ignoring = cframe.dead_tree || !((operand.X_add_number != 0) ^ arg);
current_cframe = (struct conditional_frame *) obstack_copy (&cond_obstack, &cframe, sizeof (cframe));
return;
} /* s_if() */
void
s_endif (arg)
int arg;
{
struct conditional_frame *hold;
if (current_cframe == NULL)
{
as_bad ("\".endif\" without \".if\"");
}
else
{
hold = current_cframe;
current_cframe = current_cframe->previous_cframe;
obstack_free (&cond_obstack, hold);
} /* if one pop too many */
return;
} /* s_endif() */
void
s_else (arg)
int arg;
{
if (current_cframe == NULL)
{
as_bad (".else without matching .if - ignored");
}
else if (current_cframe->else_seen)
{
as_bad ("duplicate \"else\" - ignored");
as_bad_where (current_cframe->else_file_line.file,
current_cframe->else_file_line.line,
"here is the previous \"else\"");
as_bad_where (current_cframe->if_file_line.file,
current_cframe->if_file_line.line,
"here is the previous \"if\"");
}
else
{
as_where (¤t_cframe->else_file_line.file,
¤t_cframe->else_file_line.line);
if (!current_cframe->dead_tree)
{
current_cframe->ignoring = !current_cframe->ignoring;
} /* if not a dead tree */
current_cframe->else_seen = 1;
} /* if error else do it */
return;
} /* s_else() */
void
s_ifeqs (arg)
int arg;
{
as_bad ("ifeqs not implemented.");
return;
} /* s_ifeqs() */
void
s_end (arg)
int arg;
{
return;
} /* s_end() */
int
ignore_input ()
{
/* We cannot ignore certain pseudo ops. */
if (input_line_pointer[-1] == '.'
&& ((input_line_pointer[0] == 'i'
&& (!strncmp (input_line_pointer, "if", 2)
|| !strncmp (input_line_pointer, "ifdef", 5)
|| !strncmp (input_line_pointer, "ifndef", 6)))
|| (input_line_pointer[0] == 'e'
&& (!strncmp (input_line_pointer, "else", 4)
|| !strncmp (input_line_pointer, "endif", 5)))))
{
return 0;
}
return ((current_cframe != NULL) && (current_cframe->ignoring));
} /* ignore_input() */
static void
initialize_cframe (cframe)
struct conditional_frame *cframe;
{
memset (cframe, 0, sizeof (*cframe));
as_where (&cframe->if_file_line.file,
&cframe->if_file_line.line);
cframe->previous_cframe = current_cframe;
cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
return;
} /* initialize_cframe() */
/*
* Local Variables:
* fill-column: 131
* comment-column: 0
* End:
*/
/* end of cond.c */
|
