From: Nick Alcock <nick.alcock@oracle.com>
To: Alan Modra <amodra@gmail.com>
Cc: binutils@sourceware.org, Indu Bhagat <gitlab@linux-git.oraclecorp.com>
Subject: Re: [PATCH 4/4] libctf: get the offsets of fields of unnamed structs/unions right
Date: Mon, 27 Mar 2023 13:38:19 +0100 [thread overview]
Message-ID: <878rfinzd0.fsf@esperi.org.uk> (raw)
In-Reply-To: <ZCF8ekefjBi5Ky5R@squeak.grove.modra.org> (Alan Modra's message of "Mon, 27 Mar 2023 21:52:34 +1030")
On 27 Mar 2023, Alan Modra said:
> On Mon, Mar 27, 2023 at 11:27:40AM +0100, Nick Alcock wrote:
>> On 25 Mar 2023, Alan Modra verbalised:
>> > On Fri, Mar 24, 2023 at 01:36:25PM +0000, Nick Alcock via Binutils wrote:
>> >> * testsuite/libctf-lookup/unnamed-field-info*: New test.
>> >
>> > arm-linux-gnueabi +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > hppa-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > m68k-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > microblaze-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > mips-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > powerpc-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > s390-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>> > sh4-linux-gnu +FAIL: /home/alan/src/binutils-gdb/libctf/testsuite/libctf-lookup/unnamed-field-info.c
>>
>> Weird. I tested on two of those! (arm and powerpc).
>>
>> Are they all 32-bit platforms? It looks like it.
>
> Yes, and built on x86_64-linux. Which is why things go wrong.
> "lookup" is compiled and running on x86_64, thus compiled in offsets
> are for the 64-bit host. The test objects are compiled by the
> relevant target compiler, in this case all 32-bit. Things would break
> with a 32-bit host and 64-bit targets too of course.
Oh ugh of course. I need to run this one only where host == target.
Will fix. (How did this not come up in my cross-compiler testing?
I guess they all had similar offsets -- I think most of my cross-targers
are 64-bit... I need to add a 32-bit one, of course.)
>> I'll take a look. Maybe I can just make the test less picky -- all we're
>> actually interested in for this bug is "CTF says 0". But this is worthy
>> of investigation regardless. It's just as likely to be a compiler bug
>> as a bug in libctf, I'd guess.
>
> It's funny how we tend to not suspect the test. :)
Yeah. Stands to reason an evil trick like that won't work everywhere!
--
NULL && (void)
next prev parent reply other threads:[~2023-03-27 12:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-24 13:36 [PATCH 1/4] libctf: fix assertion failure with no system qsort_r Nick Alcock
2023-03-24 13:36 ` [PATCH 2/4] libctf: work around an uninitialized variable warning Nick Alcock
2023-03-24 13:36 ` [PATCH 3/4] libctf: fix a comment typo Nick Alcock
2023-03-24 13:36 ` [PATCH 4/4] libctf: get the offsets of fields of unnamed structs/unions right Nick Alcock
2023-03-25 6:07 ` Alan Modra
2023-03-27 10:27 ` Nick Alcock
2023-03-27 11:22 ` Alan Modra
2023-03-27 12:38 ` Nick Alcock [this message]
2023-04-06 11:46 ` Nick Alcock
2023-04-08 15:50 ` Nick Alcock
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