llvm dev - Jan 2009 - [LLVMdev] Build problems on MinGW solved - possible llvm-config bug

Hi Anton
>> $ g++ -g tut1.cpp `llvm-config --cxxflags --ldflags --libs core` -o
tut1
>> /mingw/lib/libLLVMSystem.a(Process.o):Process.cpp:(.text+0x8d):
>> undefined reference to `GetProcessMemoryInfo at 12'
>> collect2: ld returned 1 exit status
> I believe you will need additional libraries like imagehlp and psapi.
I have /lib/libimagehlp.a  and /lib/libpsapi.a

nm --defined-only /lib/libpsapi.a | grep "GetProcessMemoryInfo" -

returns:

00000000 T _GetProcessMemoryInfo at 12
00000000 I __imp__GetProcessMemoryInfo at 12

And llvm-config seems to be asking for them to be picked up:

-I//include  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -O2
-fomit-frame-pointer  -Woverloaded-virtual
-L//lib  -lpsapi -limagehlp -lm
-lLLVMCore -lLLVMSupport -lLLVMSystem

So I'm still mystified.

Best regards,
Duncan

Duncan Pierce <duncan at duncanpierce.org> writes:
> I have /lib/libimagehlp.a  and /lib/libpsapi.a
>
> nm --defined-only /lib/libpsapi.a | grep "GetProcessMemoryInfo" -
>
> returns:
>
> 00000000 T _GetProcessMemoryInfo at 12
> 00000000 I __imp__GetProcessMemoryInfo at 12
>
> And llvm-config seems to be asking for them to be picked up:
>
> -I//include  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -O2
> -fomit-frame-pointer  -Woverloaded-virtual
> -L//lib  -lpsapi -limagehlp -lm
> -lLLVMCore -lLLVMSupport -lLLVMSystem
>
> So I'm still mystified.
Put them at the end of the library list:

-lLLVMCore -lLLVMSupport -lLLVMSystem -limagehlp -lpsapi -lm

Unless recently changed, mingw's ld resolves symbols sequentially on the
library list, it does not look on previously processed libraries, so
order is relevant.

If llvm-config puts psapi and imagehlp at the beginning of the list,
that probably is a bug on llvm-config. But llvm-config's source code
does not mention psapi and/or imagehlp at all.

Are you sure that -lpsapi and -limagehlp are on the output of
llvm-config? They are not on my mingw's LLVM, although it is several
weeks old.

-- 
Oscar

Óscar Fuentes <ofv <at> wanadoo.es> writes:
> Duncan Pierce <duncan <at> duncanpierce.org> writes:
> 
> > I have /lib/libimagehlp.a  and /lib/libpsapi.a
> > And llvm-config seems to be asking for them to be picked up:
> >
> > -I//include  -D_DEBUG  -D_GNU_SOURCE -D__STDC_LIMIT_MACROS -O2
> > -fomit-frame-pointer  -Woverloaded-virtual
> > -L//lib  -lpsapi -limagehlp -lm
> > -lLLVMCore -lLLVMSupport -lLLVMSystem
> >
> > So I'm still mystified.
> 
> Put them at the end of the library list:
> 
> -lLLVMCore -lLLVMSupport -lLLVMSystem -limagehlp -lpsapi -lm
This works. I had a look at changing the llvm-config.in.in but my Perl hacking
skills aren't up to getting --libnames and --libfiles to work as well as
--libs.

I discovered one other thing that was causing me problems on MinGW: if I use the
msys.bat to open a terminal llvm-config inserts double slashes at the start of
any absolute path it generates (e.g. //lib/LLVMX86CodeGen.o) - this breaks g++.

If I do the same thing from a DOS prompt running bash, slashes don't get
doubled
and everything works fine.

Thanks once again Óscar and Anton.

Duncan Pierce