#include <llvm/Pass.h>
#include <llvm/PassManager.h>
#include <llvm/IR/BasicBlock.h>
#include <llvm/IR/Constants.h>
#include <llvm/IR/DerivedTypes.h>
#include <llvm/IR/Function.h>
#include <llvm/IR/GlobalVariable.h>
#include <llvm/IR/IRPrintingPasses.h>
#include <llvm/IR/Instructions.h>
#include <llvm/IR/LLVMContext.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Verifier.h>
#include <llvm/Support/FormattedStream.h>
#include <vector>

using namespace llvm;

Module *makeLLVMModule();

int main(int argc, char **argv) {
  Module *Mod = makeLLVMModule();
  PassManager PM;
  PM.add(createVerifierPass());
  PM.add(createPrintModulePass(outs()));
  PM.run(*Mod);
  return 0;
}

Module *makeLLVMModule() {
  // Module Construction
  Module *mod = new Module("test.ll", getGlobalContext());
  mod->setDataLayout("e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128");
  mod->setTargetTriple("i386-pc-linux-gnu");

  // Type Definitions
  std::vector<Type *> FuncTy_0_args;
  FuncTy_0_args.push_back(IntegerType::get(mod->getContext(), 32));
  FuncTy_0_args.push_back(IntegerType::get(mod->getContext(), 32));
  FunctionType *FuncTy_0 = FunctionType::get(
      /*Result=*/IntegerType::get(mod->getContext(), 32),
      /*Params=*/FuncTy_0_args,
      /*isVarArg=*/false);

  // Function Declaration
  Function *func_sum = mod->getFunction("sum");
  if (!func_sum) {
    func_sum = Function::Create(
        /*Type=*/FuncTy_0,
        /*Linkage=*/GlobalValue::ExternalLinkage,
        /*Name=*/"sum", mod);
    func_sum->setCallingConv(CallingConv::C);
  }

  // Function Definition
  {
    Function::arg_iterator args = func_sum->arg_begin();
    Value *int32_x = args++;
    int32_x->setName("x");
    Value *int32_y = args++;
    int32_y->setName("y");

    BasicBlock *label_entry =
        BasicBlock::Create(mod->getContext(), "entry", func_sum, 0);

    // Block entry (label_entry)
    BinaryOperator *int32_add = BinaryOperator::Create(
        Instruction::Add, int32_x, int32_y, "add", label_entry);
    ReturnInst::Create(mod->getContext(), int32_add, label_entry);
  }

  return mod;
}