vmdevirt/src/main.cpp

#include "llvm/Bitcode/BitcodeWriter.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IRPrintingPasses.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Pass.h"
#include "llvm/Support/raw_ostream.h"
#include <stdio.h>

using namespace llvm;
Module *makeLLVMModule( LLVMContext &Context );

int main( int argc, char **argv )
{
    LLVMContext Context;
    Module *Mod = makeLLVMModule( Context );

    raw_fd_ostream r( fileno( stdout ), false );
    verifyModule( *Mod, &r );

    // Prints the module IR
    ModulePass *m = createPrintModulePass( outs(), "Module IR printer" );
    legacy::PassManager PM;
    PM.add( m );
    PM.run( *Mod );

    // Write IR to a bitcode file
    FILE *mul_add_file = fopen( "mul_add.bc", "w+" );
    raw_fd_ostream bitcodeWriter( fileno( mul_add_file ), true );
    WriteBitcodeToFile( *Mod, bitcodeWriter );

    delete Mod;
    return 0;
}

Module *makeLLVMModule( LLVMContext &Context )
{
    Module *mod = new Module( "mul_add", Context );

    FunctionCallee mul_add_fun =
        mod->getOrInsertFunction( "mul_add", Type::getInt32Ty( Context ), Type::getInt32Ty( Context ),
                                  Type::getInt32Ty( Context ), Type::getInt32Ty( Context ) );
    Function *mul_add = cast< Function >( mul_add_fun.getCallee() );

    mul_add->setCallingConv( CallingConv::C );
    Function::arg_iterator args = mul_add->arg_begin();
    Value *x = args++;
    x->setName( "x" );
    Value *y = args++;
    y->setName( "y" );
    Value *z = args++;
    z->setName( "z" );

    BasicBlock *block = BasicBlock::Create( Context, "entry", mul_add );
    IRBuilder<> builder( block );
    Value *tmp = builder.CreateBinOp( Instruction::Mul, x, y, "tmp" );
    Value *tmp2 = builder.CreateBinOp( Instruction::Add, tmp, z, "tmp2" );
    builder.CreateRet( tmp2 );

    return mod;
}