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digitalmars.D.learn - Runtime error when accessing static data in a DLL

reply "Phil Deets" <pjdeets2 gmail.com> writes:
I'm writing a DLL in D which will be loaded (not automatically, but by  
LoadLibrary) by a C application (the Lua interpreter). I'm having problems  
with globals and static data. Everything is fine if I only access stuff on  
the stack, but as soon as I access a global or a static class variable,  
either the program crashes or if I am still in DllMain, the LoadLibrary  
function will fail and GetLastError will indicate an error with the  
message "Invalid access to memory location.".

I'll work on reproducing it in a smaller scale, but does anyone know how  
to fix it?

In case it is helpful info, in DllMain under the DLL_PROCESS_ATTACH case,  
I am just calling Runtime.initialize; even though the sample calls  
gc_init, _minit, _moduleCtor, and runModuleUnitTests.
Dec 24 2009
next sibling parent reply Richard Webb <webby beardmouse.org.uk> writes:
Sounds like you might be running into this:
http://d.puremagic.com/issues/show_bug.cgi?id=3342
Dec 24 2009
parent reply "Phil Deets" <pjdeets2 gmail.com> writes:
On Thu, 24 Dec 2009 12:49:42 -0500, Richard Webb <webby beardmouse.org.uk>  
wrote:


 Sounds like you might be running into this:
 http://d.puremagic.com/issues/show_bug.cgi?id=3342


Thanks for the link. That is probably my problem since I'm running Windows  
XP.

Phil
Dec 24 2009
parent reply "Phil Deets" <pjdeets2 gmail.com> writes:
On Thu, 24 Dec 2009 13:10:14 -0500, Phil Deets <pjdeets2 gmail.com> wrote:


 On Thu, 24 Dec 2009 12:49:42 -0500, Richard Webb  
 <webby beardmouse.org.uk> wrote:


 Sounds like you might be running into this:
 http://d.puremagic.com/issues/show_bug.cgi?id=3342


 Thanks for the link. That is probably my problem since I'm running  
 Windows XP.

 Phil


I'm quite confident now that this is the issue. I added my vote to the  
bug. Does anybody know how much the runtime uses TLS? I'm thinking about  
the possibility of adding __gshared to all its static data.

An alternative workaround would be to install Vista or 7, but although I  
do have a legal Vista install disk, I would prefer an upgrade since I  
don't want to reinstall all my programs. Also, my computer barely meets  
Vista's minimum requirements.

I also might be able to rewrite lua.exe in D and preload my code in the  
executable. Most of Lua's functionality is in a library which would not  
need to be rewritten so this might be feasible.
Dec 24 2009
parent Don <nospam nospam.com> writes:
Phil Deets wrote:

 On Thu, 24 Dec 2009 13:10:14 -0500, Phil Deets <pjdeets2 gmail.com> wrote:
 

 On Thu, 24 Dec 2009 12:49:42 -0500, Richard Webb 
 <webby beardmouse.org.uk> wrote:


 Sounds like you might be running into this:
 http://d.puremagic.com/issues/show_bug.cgi?id=3342


 Thanks for the link. That is probably my problem since I'm running 
 Windows XP.

 Phil


 
 I'm quite confident now that this is the issue. I added my vote to the 
 bug.


Yes, it's the most serious bug in Bugzilla. (It's quite appalling that 
such a terrible bug has existed in Windows for so long). I wish we had a 
solution to this. I guess we could replace all uses of implicit TLS with 
a Windows function call -- it'd be slow, but it ought to work.


  Does anybody know how much the runtime uses TLS? I'm thinking about

 the possibility of adding __gshared to all its static data.
 
 An alternative workaround would be to install Vista or 7, but although I 
 do have a legal Vista install disk, I would prefer an upgrade since I 
 don't want to reinstall all my programs. Also, my computer barely meets 
 Vista's minimum requirements.




 
 I also might be able to rewrite lua.exe in D and preload my code in the 
 executable. Most of Lua's functionality is in a library which would not 
 need to be rewritten so this might be feasible.
Dec 26 2009
prev sibling parent "Phil Deets" <pjdeets2 gmail.com> writes:
On Thu, 24 Dec 2009 10:49:01 -0500, Phil Deets <pjdeets2 gmail.com> wrote:


 I'll work on reproducing it in a smaller scale


Reduced test case:

test.c (compiled with Visual C++ 2008 Express Edition)

// Adapted from sample code at  
http://msdn.microsoft.com/en-us/library/ms680582(VS.85).aspx
#include <windows.h>
#include <strsafe.h>

void main()
{
	if(!LoadLibraryA("d.dll"))
	{
		LPVOID lpMsgBuf;
		DWORD dw = GetLastError();
		FormatMessageA(
			FORMAT_MESSAGE_ALLOCATE_BUFFER |
			FORMAT_MESSAGE_FROM_SYSTEM |
			FORMAT_MESSAGE_IGNORE_INSERTS,
			NULL,
			dw,
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
			(LPSTR) &lpMsgBuf,
			0, NULL );
		printf("LoadLibrary failed with error %d: %s\n", dw, lpMsgBuf);
		LocalFree(lpMsgBuf);
	}
}

dll.d:

import std.c.windows.windows;
int x;
extern (Windows) BOOL DllMain(HINSTANCE, ULONG, LPVOID) {
	x=0;
	return true;
}

dll.def:

LIBRARY         "d.dll"
EXETYPE         NT
SUBSYSTEM       WINDOWS
CODE            SHARED EXECUTE
DATA            WRITE

Compiled with:

dmd dll.d dll.def -ofd.dll

When I run the C app, I get the output "LoadLibrary failed with error 998:  
Invalid access to memory location."
Dec 24 2009