How do you compile C++ programs that include LLVM API headers? - compilation

Question

I'm trying to use the C++ compiler to compile the following program:
#include <stdio.h>
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/IR/Module.h"
int main( int argc, char* argv[] )
{
if( argc < 2 )
llvm::errs() << "Expected an argument - IR file name\n";
llvm::LLVMContext &context = llvm::getGlobalContext();
llvm::SMDiagnostic err;
llvm::Module* module = llvm::ParseIRFile( argv[1], err, context );
if( !mod )
{
err.print( argv[0], errs() );
return 1;
}
return 0;
}
I'm trying to compile the program using the following command:
clang++ main.cpp -o main
However, when I compile, I'm getting the following compile error:
main.cpp:2:10: fatal error: 'llvm/IR/LLVMContext.h' file not found
#include "llvm/IR/LLVMContext.h"
^
1 error generated.
In this case, I'm not exactly sure how to link the LLVM API headers when compiling main.cpp with Clang.
Any help would be greatly appreciated.

Answer 1

You can use the following command:
g++ -std=c++11 main.cpp `llvm-config --system-libs --cppflags --ldflags --libs core` -o main
Where --libs and --system-libs flags are used for linking and --cppflags takes care of include paths.
Thank You

Answer 2

You need LLVM checked out or installed somewhere on your system. You can download a binary release (with headers and libraries you can build against) as explained here: http://llvm.org/releases/download.html#3.5
You can also check out LLVM from its SVN repository as explained here: http://llvm.org/docs/GettingStarted.html#checkout
Once you do that, I recommend looking at the llvm-clang-samples repository that comes with a Makefiles showing how to build sample programs vs. an up-to-date LLVM.