From: Eliot Moss <moss@cs.umass.edu>
To: cygwin@cygwin.com
Subject: Re: Help debugging a dll issue
Date: Fri, 20 May 2016 13:46:00 -0000 [thread overview]
Message-ID: <739fe087-4386-3916-84e7-368ac27a5ae0@cs.umass.edu> (raw)
In-Reply-To: <20160520133659.GD12938@dimstar.local.net>
On 5/20/2016 9:36 AM, Duncan Roe wrote:
> On Fri, May 20, 2016 at 08:02:20AM -0400, Eliot Moss wrote:
>> On 5/20/2016 7:26 AM, Duncan Roe wrote:
>>
>>> Hi Eliot,
>>>
>>> Do you know what is the name of the totally different symbol? (maybe from nm -D)
>>
>> Yes -- I have been using nm and objdump to examine the relevant files. The dll
>> is called libpypy-c.dll. The symbol I want to bind to is pypy_main_startup, and
>> its proper value (as returned by nm and objdump) is 0x6410ac60. The result I
>> get is the value of symbol pypy_g_PyNumber_Negative (an automatically generated
>> C function), which is 0x63443f00.
>>
>> I wonder if these collide in some internal hash table and the hash lookup (or
>> the table building) is broken in some subtle way.
>>
>> Regards -- Eliot
>>
> Does findit give the same answer for both symbols?
>
> If you could build your library and libdl.a with debug (-g) then you might be
> able to see how the lookup goes wrong.
>
> HTH ... Duncan.
Well, the wrong answer comes back from the Windows routine GetProcAddress. The
bug seems to lie either in the Windows run-time code or in how the dll is being
built. I am trying giving one of the functions a different name to see what
happens (if it's a hash collision effect, presumably something will show up
different).
Regards -- EM
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next prev parent reply other threads:[~2016-05-20 13:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-20 2:54 Eliot Moss
[not found] ` <CABHT960Yx_bg-NaHWcxePEV+Xz74NaVtsu+NjkrSZs4-62rCOA@mail.gmail.com>
2016-05-20 10:38 ` Eliot Moss
2016-05-20 11:26 ` Duncan Roe
2016-05-20 12:02 ` Eliot Moss
2016-05-20 13:37 ` Duncan Roe
2016-05-20 13:46 ` Eliot Moss [this message]
2016-05-21 23:30 ` Eliot Moss
2016-05-22 1:46 ` René Berber
2016-05-22 2:53 ` Eliot Moss
2016-05-22 2:58 ` Duncan Roe
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