llvm dev - Jan 2014 - [LLVMdev] [windows+mingw] is there a way to tell llvm to generate symbol with a leading _ ?

Hello,

I was recommended to post my question here.

Here is the context for my question.
On Windows, mingw generates symbols with a leading _ in their name.

I have a project that combines regular C libraries compiled by mingw
(runtime.a) and IR code that I generated and compile via llvm libraries
(generated.a).
In my case generated.a uses variables exported by runtime.a.
And here lies the run, while those variables have the same name in the c
files that make runtime.a and in the IR code that I feed llvm, once they
get compiled, the former has a leading _ and the latter not.

To complicate things a little further, that project already work on macosx
and linux.
So, I can't want to rename the said variables in the IR code without
recreating ripples on the platforms.
Which I do want to avoid.

What I am looking for is the switch to tell llvm assembler "hey, we're
on
windows, please add the dreaded _".
Does such thing exist?

Where can I look for it?

I was told that I should  add "m:w" to your data layout string. How
so?
By using the feature parameter of Target?

createTargetMachine     (     StringRef      Triple,
        StringRef      CPU,
        StringRef      Features,
        const TargetOptions &      Options,
        Reloc::Model      RM = Reloc::Default,
        CodeModel::Model      CM = CodeModel::Default,
        CodeGenOpt::Level      OL = CodeGenOpt::Default
    )         const [inline]


Cheers,
Carl.

PS: I'm posting in the correct mailing list?
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On 25 January 2014 18:44, Carl <name.is.carl at gmail.com>
wrote:
>
> Hello,
>
> I was recommended to post my question here.
>
...
> I was told that I should  add "m:w" to your data layout string.
How so?
> By using the feature parameter of Target?
No, if this is codegen, it should just work.  Check computeDataLayout
in X86TargetMachine.cpp. The call to getManglingComponent should be
adding the "m:w".

If codegen is not involved, you need to set the datalayout in the
Module by calling setDataLayout.

Cheers,
Rafael