binutils-gdb/gas/cond.c

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/* 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
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#include "as.h"
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#include "obstack.h"
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/* This is allocated to grow and shrink as .ifdef/.endif pairs are scanned. */
struct obstack cond_obstack;
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struct file_line
{
char *file;
unsigned int line;
}; /* file_line */
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/* 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 */
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static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
static char *get_mri_string PARAMS ((int, int *));
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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);
ignore_rest_of_line ();
}
else
{
char c;
c = get_symbol_end ();
symbolP = symbol_find (name);
*input_line_pointer = c;
initialize_cframe (&cframe);
cframe.ignoring = cframe.dead_tree || !((symbolP != 0) ^ arg);
current_cframe = ((struct conditional_frame *)
obstack_copy (&cond_obstack, &cframe,
sizeof (cframe)));
demand_empty_rest_of_line ();
} /* if a valid identifyer name */
} /* s_ifdef() */
void
s_if (arg)
int arg;
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{
expressionS operand;
struct conditional_frame cframe;
int t;
SKIP_WHITESPACE (); /* Leading whitespace is part of operand. */
if (current_cframe != NULL && current_cframe->ignoring)
{
operand.X_add_number = 0;
while (! is_end_of_line[(unsigned char) *input_line_pointer])
++input_line_pointer;
}
else
{
expression (&operand);
if (operand.X_op != O_constant)
as_bad ("non-constant expression in \".if\" statement");
}
switch ((operatorT) arg)
{
case O_eq: t = operand.X_add_number == 0; break;
case O_ne: t = operand.X_add_number != 0; break;
case O_lt: t = operand.X_add_number < 0; break;
case O_le: t = operand.X_add_number <= 0; break;
case O_ge: t = operand.X_add_number >= 0; break;
case O_gt: t = operand.X_add_number > 0; break;
default:
abort ();
}
/* If the above error is signaled, this will dispatch
using an undefined result. No big deal. */
initialize_cframe (&cframe);
cframe.ignoring = cframe.dead_tree || ! t;
current_cframe = ((struct conditional_frame *)
obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
demand_empty_rest_of_line ();
} /* s_if() */
/* Get a string for the MRI IFC or IFNC pseudo-ops. */
static char *
get_mri_string (terminator, len)
int terminator;
int *len;
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{
char *ret;
char *s;
SKIP_WHITESPACE ();
s = ret = input_line_pointer;
if (*input_line_pointer == '\'')
{
++s;
++input_line_pointer;
while (! is_end_of_line[(unsigned char) *input_line_pointer])
{
*s++ = *input_line_pointer++;
if (s[-1] == '\'')
{
if (*input_line_pointer != '\'')
break;
++input_line_pointer;
}
}
SKIP_WHITESPACE ();
}
else
{
while (*input_line_pointer != terminator
&& ! is_end_of_line[(unsigned char) *input_line_pointer])
++input_line_pointer;
s = input_line_pointer;
while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
--s;
}
*len = s - ret;
return ret;
}
/* The MRI IFC and IFNC pseudo-ops. */
void
s_ifc (arg)
int arg;
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{
char *s1, *s2;
int len1, len2;
int res;
struct conditional_frame cframe;
s1 = get_mri_string (',', &len1);
if (*input_line_pointer != ',')
as_bad ("bad format for ifc or ifnc");
else
++input_line_pointer;
s2 = get_mri_string (';', &len2);
res = len1 == len2 && strncmp (s1, s2, len1) == 0;
initialize_cframe (&cframe);
cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
current_cframe = ((struct conditional_frame *)
obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
}
void
s_endif (arg)
int arg;
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{
struct conditional_frame *hold;
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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;
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{
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 (&current_cframe->else_file_line.file,
&current_cframe->else_file_line.line);
if (!current_cframe->dead_tree)
{
current_cframe->ignoring = !current_cframe->ignoring;
} /* if not a dead tree */
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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() */
int
ignore_input ()
{
char *s;
s = input_line_pointer;
if (flag_mri
#ifdef NO_PSEUDO_DOT
|| 1
#endif
)
{
if (s[-1] != '.')
--s;
}
else
{
if (s[-1] != '.')
return (current_cframe != NULL) && (current_cframe->ignoring);
}
/* We cannot ignore certain pseudo ops. */
if (((s[0] == 'i'
|| s[0] == 'I')
&& (!strncasecmp (s, "if", 2)
|| !strncasecmp (s, "ifdef", 5)
|| !strncasecmp (s, "ifndef", 6)))
|| ((s[0] == 'e'
|| s[0] == 'E')
&& (!strncasecmp (s, "else", 4)
|| !strncasecmp (s, "endif", 5)
|| !strncasecmp (s, "endc", 4))))
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:
*/
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/* end of cond.c */