Using LLVM Libraries in C++ Project

Question

I'm currently having problem with simple project(or llvm-example for that matter). My assignment requires me to use llvm libraries, however this isn't as easy as I had hoped.

I've build LLVM using MinGW GCC and CMake. After build I can compile with clang fine. However if I create simple hello world type of program

#include "llvm-c/Core.h"

int main(int argc, char**argv)
{
  return 0;
}

and try to compile it with

clang++ main.cpp

I get

In file included from main.cpp:1:
./llvm-c/Core.h:18:10: fatal error: 'llvm-c/ErrorHandling.h' file not found
#include "llvm-c/ErrorHandling.h"

For this example I have copied contents of include directory into directory with main.cpp. After getting this issue I tried to inspect those headers and all of them have position llvm/ or llvm-c/, instead of pure relative address. I figured these libs were used to build/make llvm and libs for me to use are actually in build directory, which is where I have built llvm, but include directory in build has only about 1/2 *.h files.

I can't seem to find anything in documentation related to this and even basic llvm examples are expecting to include libs in format like llvm/Core.h

EDIT

After solving inclusion problem, now I get several other problems which seems to be linked to mingw.

This is how new program looks.

#define __STDC_LIMIT_MACROS
#define __STDC_CONSTANT_MACROS

#include <llvm-c/Core.h>

using namespace std;

int main()
{
    LLVMModuleRef rff =  LLVMModuleCreateWithName("testname");
    return 0;
}

this generates

d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(CommandLine.cpp.obj):CommandLine.cpp|| undefined reference to `__mingw_strtod'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(regerror.c.obj):regerror.c|| undefined reference to `__ms_vsnprintf'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `SHGetKnownFolderPath@16'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `_imp__CoTaskMemFree@4'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `_imp___chsize_s'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_Profile'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_Profile'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_Profile'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_Profile'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(Path.cpp.obj):Path.cpp|| undefined reference to `FOLDERID_LocalAppData'|
d:\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.9.3\..\..\..\libLLVMSupport.a(TimeValue.cpp.obj):TimeValue.cpp|| undefined reference to `_localtime32'|

I used llvm-config --libs core for linker additions.

Tried commands:

g++ main.cpp -lLLVMCore -lLLVMSupport
clang++ main.cpp -lLLVMCore -lLLVMSupport

Answer 1

Those are WinAPI references. The easiest way is to find those are google for documentation for it or go to the mingw library directory ( ..\mingw530_32\i686-w64-mingw32\lib\ ) and find in files.

So

• FOLDERID_LocalAppData is defined in libuuid.a so use the -luuid compile parameter
• _imp__CoTaskMemFree@4 is defined in libole32.a so use the -lole32 compile parameter

For me g++ -std=c++11 -ID:\Devel\install\include main.cc -LD:\Devel\install\lib -lLLVMCore -lLLVMSupport -luuid -lole32

is working as I installed the llvm to D:\Devel\install

Answer 2

If you need the headers from your-llvm/include directory instead of copying the contents of the include directory you should just specify the include path to your-llvm/include with -I option or whatever the build system requires.