Date: Mon, 1 Feb 2010 12:46:11 -0500
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: dlclose not calling destructors of static variables.
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On Mon, Feb 01, 2010 at 05:35:10PM +0000, Andrew West wrote:
>On 01/02/2010 16:26, Christopher Faylor wrote:
>> Could you clarify?  Are you saying that your test case still failed?
>>    
>
>With the change you provided my test still failed, but changing 
>m.AllocationBase to m.BaseAddress it worked.
>Unfortunately it only worked for that test cash, on trying it with a 
>full program of mine it crashed using both
>AllocationBase and BaseAddress to work out the start position of the dll.
>
>On closer examination it looks like dll_beg <-> dll_end doesn't cover 
>all the possible locations that atexits are registered from.
>I think RegionSize isn't big enough at least when I compare them to gdbs 
>"info sharedlibrary", for example:
>
>remove_dll_atexit;
>m.AllocationBase = 0x706c0000
>m.AllocationBase + m.RegionSize = 0x706c1000
>
>GDB;
>from = 0x706c1000
>to = 0x706c717c
>
>But the atexit function is registered at 0x706c10f0. Changing 
>AllocationBase to BaseAddress worked for my test case out of pure luck, 
>with my larger libraries it still failed.
>
>Looking at one of the libraries in my code that fails I get ( with the 
>atexit at 0x78351c9 )
>
>remove_dll_atexit;
>m.AllocationBase = 0x7820000
>m.AllocationBase + m.RegionSize = 0x7824000
>
>GDB;
>from = 0x07821000
>to = 0x079159b8
>
>With both of these examples I checked the dll using objdump and the 
>atexit functions where in the .text portion but RegionSize never seems 
>big enough to cover it entirely. For that last dll objdump reports the 
>text size as 61380. Of course I could be reading objdump wrong, I've 
>only every really used it to check exported functions.
>
>Cribbing from the gdb source code, it looks like they use BaseAddrees + 
>0x1000 for the start point and then call GetModuleInformation to workout 
>the size of the module.

Yeah, duh.  "they" == "me".  I should have checked gdb for this since I've
already done this research once before.

If you do find that this works, then I think this may fall into the
realm of a non-trivial patch so it may be best to just tell me what
you've found rather than provide a patch - unless you want to go through
the approval process with Red Hat.

Or, you can just wait for me to adapt what's in gdb to cygwin.  I can do
tonight when I get back to a windows system.

cgf

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