----- On May 8, 2019, at 12:08 PM, Simon Marchi simon.mar...@efficios.com wrote:
> On 2019-05-08 11:59 a.m., Mathieu Desnoyers wrote:
>> What compiler do you use, and which compilation flags ?
>> (it works here)
>
> "gcc (Ubuntu 7.4.0-1ubuntu1~18.04) 7.4.0", which is the system compiler on
> Ubuntu 18.04.
>
> I just built with
>
> ./configure 'CFLAGS=-g3 -O0 -fsanitize=address -Wall'
>
> and got some failures, the first one being
>
> not ok 8 - Writing and reading back 0xC07EBC7, signed
> # Failed test (test_bitfield.c:run_test_signed() at line 224)
> # Failed reading value written "signed char"-wise, with start=0 and length=29.
> Read FFFFFFFFFFFFFFC7
> # 0xFFFFFFC7 0xFFFFFFEB 0x7 0xC 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
> 0x0
> 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0
>
> The test passes without the patch. If you can't reproduce it easily, I can
> dig
> on my side.
it fails here too... the executable test-bitfield was renamed to test_bitfield
and I had an old tree with the prior executable. Will investigate.
Thanks,
Mathieu
>
>>>>
>>>> /*
>>>> * bt_bitfield_write - write integer to a bitfield in native endianness
>>>> @@ -108,15 +113,15 @@ do {
>>>> \
>>>> \
>>>> /* Trim v high bits */ \
>>>> if (__length < sizeof(__v) * CHAR_BIT) \
>>>> - __v &= ~((~(typeof(__v)) 0) << __length); \
>>>> + __v &= (typeof(__v)) ~(_bt_fill_mask(typeof(__v)) << __length);
>>>> \
>>>
>>> Not a blocker, but this operation is done enough times that it might be
>>> worth
>>> giving it a name and make a macro for it. It could help make this big macro
>>> more readable, and we could test it on its own if needed.
>>>
>>> /* Generate a mask of type `type` with the `length` least significant bits
>>> set.
>>> */
>>>
>>> #define _bt_make_mask(type, length) \
>>> ((type) ~(_bt_fill_mask(type) << length))
>>
>> Good point! Will do. Missing () around "length" though.
>
> Right, and I should have mentioned I didn't actually test that macro, so
> handle
> with care!
>
> Simon
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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