From: Alan Hayward <Alan.Hayward@arm.com>
To: Pedro Alves <palves@redhat.com>
Cc: GDB Patches <gdb-patches@sourceware.org>, nd <nd@arm.com>
Subject: Re: [PATCH v3 3/3] Aarch64: Fix segfault when casting dummy calls
Date: Tue, 30 Oct 2018 11:13:00 -0000 [thread overview]
Message-ID: <8DDC5D9D-D601-4D6D-A21F-7A35FF92C6EA@arm.com> (raw)
In-Reply-To: <830e7c3b-3469-6cea-61d1-5a1e7e230de1@redhat.com>
> On 29 Oct 2018, at 18:13, Pedro Alves <palves@redhat.com> wrote:
>
> On 10/29/2018 02:56 PM, Alan Hayward wrote:
>
>> A-ha! Now I understand why I get two calls into _push_dummy_call.
>>
>> So to answer your question, the TYPE_CODE_PTR->TYPE_CODE_INT is the malloc call.
>>
>> Then the next call to _push_dummy_call has a return type of 0, as expected.
>> This doesn’t segfault because it goes into language_pass_by_reference which
>> routes to default_pass_by_reference. The same as the C shared library version.
>>
>>
>> I’ve updated the test so it does {c,c++}*{debug nodebug}.
>> I can also update it to do both shared lib and non shared lib too. That should
>> cover everything.
> But still, why do you see a difference between shared library and non-shared
> library?
In all cases the function type is the same.
The difference is because with c++ && shared library, the code ends up in
gnuv3_pass_by_reference(), which means it’s using the GNU G++ Version 3 ABI,
whereas with any other options (non shared or c) it ends up in
default_pass_by_reference().
Looking at the doc for GNU G++ Version 3 ABI:
https://gcc.gnu.org/onlinedocs/libstdc++/manual/abi.html
The library needs to be linked against libstdc++.so to use it.
A quick ldd shows only the c++ .so is linked against it.
Alan.
next prev parent reply other threads:[~2018-10-30 11:13 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 14:49 [PATCH v3 0/3] " Alan Hayward
2018-10-11 14:49 ` [PATCH v3 1/3] Use enum for return method for " Alan Hayward
2018-10-19 11:28 ` Pedro Alves
2018-10-11 14:49 ` [PATCH v3 2/3] Pass return_method to _push_dummy_call Alan Hayward
2018-10-19 11:31 ` Pedro Alves
2018-10-11 14:49 ` [PATCH v3 3/3] Aarch64: Fix segfault when casting dummy calls Alan Hayward
2018-10-19 11:36 ` Pedro Alves
2018-10-23 16:08 ` Alan Hayward
2018-10-24 15:15 ` Pedro Alves
2018-10-29 11:58 ` Alan Hayward
2018-10-29 12:38 ` Pedro Alves
2018-10-29 14:56 ` Alan Hayward
2018-10-29 18:13 ` Pedro Alves
2018-10-30 11:13 ` Alan Hayward [this message]
2018-10-30 16:31 ` Pedro Alves
2018-10-30 17:09 ` Alan Hayward
2018-10-30 17:40 ` Pedro Alves
2018-10-18 9:50 ` [PING][PATCH v3 0/3] " Alan Hayward
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