Re: [RFA/mips] Fix crash trying to print long double float

Andrew Cagney
2004-08-07T17:18:56Z

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>>>> + format = NULL;
>>>> + if (format == NULL)
>>>> + error ("This GDB does not support %d-bit floating-point values.",
>>>> + len & TARGET_CHAR_BIT);
>>>> + return format;
>>>> }
>>
>>
>>
>> Why do you use a variable? wouldn't have it been simpler to
>> add one line at the end like this:
>>
>> error ("bla bla bla");
>> return NULL; /* Will never be reached. */
>
>
> And:
> if (TARGET_FLOAT_FORMAT != NULL && len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
> return TARGET_FLOAT_FORMAT;
> ...
> else
> error ("blah, blah");
> I don't trust *_FORMAT to be non-NULL.

By deleting architecture methods of my PPC config I reproduced the crash
(outch!). I've committed the attached to both the mainline and branch
(the error message was tweaked slightly).

Andrew

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2004-08-07 Andrew Cagney <cagney@gnu.org>

* doublest.c: Update copyright.
(floatformat_from_length): Call error when floatformat is NULL.
(extract_floating_by_length): Remove NULL fmt check.
(store_floating_by_length): Ditto.

Index: doublest.c
===================================================================
RCS file: /cvs/src/src/gdb/doublest.c,v
retrieving revision 1.18
diff -p -u -r1.18 doublest.c
--- doublest.c 29 Jul 2004 19:33:22 -0000 1.18
+++ doublest.c 7 Aug 2004 17:09:17 -0000
@@ -1,8 +1,8 @@
/* Floating point routines for GDB, the GNU debugger.

Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
- 1996, 1997, 1998, 1999, 2000, 2001, 2003 Free Software Foundation,
- Inc.
+ 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004 Free Software
+ Foundation, Inc.

This file is part of GDB.

@@ -618,8 +618,8 @@ floatformat_from_doublest (const struct

\f
/* Return a floating-point format for a floating-point variable of
- length LEN. Return NULL, if no suitable floating-point format
- could be found.
+ length LEN. If no suitable floating-point format is found, an
+ error is thrown.

We need this functionality since information about the
floating-point format of a type is not always available to GDB; the
@@ -633,12 +633,13 @@ floatformat_from_doublest (const struct
static const struct floatformat *
floatformat_from_length (int len)
{
+ const struct floatformat *format;
if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT)
- return TARGET_FLOAT_FORMAT;
+ format = TARGET_FLOAT_FORMAT;
else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT)
- return TARGET_DOUBLE_FORMAT;
+ format = TARGET_DOUBLE_FORMAT;
else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT)
- return TARGET_LONG_DOUBLE_FORMAT;
+ format = TARGET_LONG_DOUBLE_FORMAT;
/* On i386 the 'long double' type takes 96 bits,
while the real number of used bits is only 80,
both in processor and in memory.
@@ -646,9 +647,13 @@ floatformat_from_length (int len)
else if ((TARGET_LONG_DOUBLE_FORMAT != NULL)
&& (len * TARGET_CHAR_BIT ==
TARGET_LONG_DOUBLE_FORMAT->totalsize))
- return TARGET_LONG_DOUBLE_FORMAT;
-
- return NULL;
+ format = TARGET_LONG_DOUBLE_FORMAT;
+ else
+ format = NULL;
+ if (format == NULL)
+ error ("Unrecognized %d-bit floating-point type.",
+ len & TARGET_CHAR_BIT);
+ return format;
}

const struct floatformat *
@@ -675,12 +680,6 @@ extract_floating_by_length (const void *
const struct floatformat *fmt = floatformat_from_length (len);
DOUBLEST val;

- if (fmt == NULL)
- {
- warning ("Can't extract a floating-point number of %d bytes.", len);
- return NAN;
- }
-
floatformat_to_doublest (fmt, addr, &val);
return val;
}
@@ -699,13 +698,6 @@ store_floating_by_length (void *addr, in
{
const struct floatformat *fmt = floatformat_from_length (len);

- if (fmt == NULL)
- {
- warning ("Can't store a floating-point number of %d bytes.", len);
- memset (addr, 0, len);
- return;
- }
-
floatformat_from_doublest (fmt, &val, addr);
}