gistfile1.hpp

/**
 * g++  `llvm-config --cxxflags`  -c -o test.o test.cpp
 * g++ -o test `llvm-config --ldflags --libs` test.o
 */

#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/ModuleProvider.h"
#include "llvm/Analysis/Verifier.h"
#include "llvm/ExecutionEngine/JIT.h"
#include "llvm/ExecutionEngine/Interpreter.h"
#include "llvm/ExecutionEngine/GenericValue.h"
#include <iostream>

using namespace llvm;
using std::endl;

static Function *CreatePlusFunction(Module *M) {
	// Create the plus function and insert it into module M.  This function is said
	// to return an int and take two int parameters.
	Function *PlusF = cast<Function>(M->getOrInsertFunction("plus", 
				Type::Int32Ty, Type::Int32Ty,
				Type::Int32Ty, (Type *)0));

	// Get pointers to the integer arguments
	Function::arg_iterator ai = PlusF->arg_begin();
	Argument *Arg0 = ai;
	Arg0->setName("Arg0");		

	ai++;
	Argument *Arg1 = ai;
	Arg1->setName("Arg1");		

	BasicBlock* mainBB = new BasicBlock("main", PlusF);

	Value *Sum = BinaryOperator::createAdd(Arg0, Arg1, "addresult", mainBB);
	
	new ReturnInst(Sum, mainBB);

	return PlusF;
}

int
main(int argc, char *argv[]) {

	Module *M = new Module("test");
	// We are about to create the "plus" function:
	Function *PlusF = CreatePlusFunction(M);

	// Now we going to create JIT
	ExistingModuleProvider *MP = new ExistingModuleProvider(M);
	ExecutionEngine *EE = ExecutionEngine::create(MP, false);

	cerr << *M << endl;

	cerr << "verifying... " << endl;
//	if (verifyModule(*M)) {
//		std::cerr << argv[0] << ": Error constructing function!\n";
//		return 1;
//	}

	int a = 1700, b = 29;
	std::vector<GenericValue> Args(2);
	Args[0].IntVal = APInt(32, a);
	Args[1].IntVal = APInt(32, b);
	GenericValue GVret = EE->runFunction(PlusF, Args);

	// import result of execution
	cerr << "plus("<<a<<","<<b<<")=" << GVret.IntVal.toStringUnsigned(10) << endl;

	return 0;
}