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| author | Tom Tromey <tom@tromey.com> | 2018-02-21 10:36:55 -0700 |
|---|---|---|
| committer | Tom Tromey <tom@tromey.com> | 2018-02-26 09:21:08 -0700 |
| commit | 15ce8941e7d2807a3396a6874c528b24c387660a (patch) | |
| tree | 4c1cf8a075385ffb4f6a629617ec0753019d7b75 /gdb/value.c | |
| parent | d7c798565e0f12a821dd399ac3bbf5d49271169a (diff) | |
| download | gdb-15ce8941e7d2807a3396a6874c528b24c387660a.zip gdb-15ce8941e7d2807a3396a6874c528b24c387660a.tar.gz gdb-15ce8941e7d2807a3396a6874c528b24c387660a.tar.bz2 | |
Sign-extend non-bit-fields in unpack_bits_as_long
unpack_bits_as_long is documented as sign-extending its result when
the type is signed. However, it was only doing sign-extension in the
case where the field was a bitfield -- that is, not when the "bitsize"
parameter was 0, indicating the size should be taken from the type.
Also, unpack_bits_as_long was incorrectly computing the shift for
big-endian architectures for the non-bitfield case.
This patch fixes these bugs in a straightforward way. A new selftest
is included.
2018-02-26 Tom Tromey <tom@tromey.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
unittests/unpack-selftests.c.
* unittests/unpack-selftests.c: New file.
* value.c (unpack_bits_as_long): Fix bugs in non-bitfield cases.
Diffstat (limited to 'gdb/value.c')
| -rw-r--r-- | gdb/value.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/gdb/value.c b/gdb/value.c index 9cd9a2f..110d16d 100644 --- a/gdb/value.c +++ b/gdb/value.c @@ -3214,7 +3214,8 @@ value_fn_field (struct value **arg1p, struct fn_field *f, /* Unpack a bitfield of the specified FIELD_TYPE, from the object at VALADDR, and store the result in *RESULT. - The bitfield starts at BITPOS bits and contains BITSIZE bits. + The bitfield starts at BITPOS bits and contains BITSIZE bits; if + BITSIZE is zero, then the length is taken from FIELD_TYPE. Extracting bits depends on endianness of the machine. Compute the number of least significant bits to discard. For big endian machines, @@ -3244,7 +3245,10 @@ unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr, if (bitsize) bytes_read = ((bitpos % 8) + bitsize + 7) / 8; else - bytes_read = TYPE_LENGTH (field_type); + { + bytes_read = TYPE_LENGTH (field_type); + bitsize = 8 * bytes_read; + } read_offset = bitpos / 8; @@ -3262,7 +3266,7 @@ unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr, /* If the field does not entirely fill a LONGEST, then zero the sign bits. If the field is signed, and is negative, then sign extend. */ - if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val))) + if (bitsize < 8 * (int) sizeof (val)) { valmask = (((ULONGEST) 1) << bitsize) - 1; val &= valmask; |