Plug-in mechanism broken on Windows

[llvmbot]

Bugzilla Link	9078
Resolution	LATER
Resolved on	Feb 14, 2011 13:56
Version	unspecified
OS	Windows NT
Attachments	llvm side, clang side
Reporter	LLVM Bugzilla Contributor

Extended Description

In loading a Windows plug-in DLL, the DLL will have it's own copy of the clang library code and data, such that the plug-in registry node list ends up in the DLL and not the Clang executable's data space.

Making the Clang library a DLL might make it work. Alternatively, if nothing in clang references changed static data, perhaps it might work if the plug-in can get to the data it needs by the references given to it. The plug-in still needs some way to get the registry info into clang, perhaps by Clang calling a function it looks up in the DLL.

As a quick and dirty experiment, I hacked some things (see the attachments up to see if just getting the PrintFunctionNames node into the registry would let the plug-in work, and it seemed to work. Perhaps with some macro magic that defines a unique function based on the plug-in name, the connection could be made that way.

Anyway, that's the extent of what I know about it. How does this work on Linux?

[llvmbot]

In loading a Windows plug-in DLL, the DLL will have it's own copy of the clang
library code and data, such that the plug-in registry node list ends up in the
DLL and not the Clang executable's data space.

Please see also the implementation of ENABLE_SHARED on mingw-msys/autoconf. In case of "llvm/opt" and "llvm/bugpoint", plugins may be available with --enable-shared.

AFAIK no one is working for win32's plugin support on cmake.

In general, DLL does not seek symbols from main module. Plugin-capable softwares, (eg. perl, python), have "The Big DLL". We may have "clang.dll" as a big dll (exports C++ symbols and contains all libs) someday.

I will work on this at any opportunity. ;)

[lattner]

Hi John,

Please send patches to llvm/cfe-commits, thanks!

[llvmbot]

llvm side
working on a better patch that I will submit to cfe-commit

[llvmbot]

clang side
working on a better patch that I will submit to cfe-commit