How to store the generated LLVM-IR code of a llvm::Module to a string?

Question

The Fibonacciexample of LLVM prints out LLVM IR using errs() << *theModule.

Is there any function that is able to store the generated LLVM IR to a (vector of) string or any other variable rather than just print it out? (e.g., std::string llvm_IR = theModule->getIR())

I been searching llvm::Module Class Reference and get nothing helpful on it.

Part of Fibonacci.cpp:

//CreateFibFunction is defined previously to generate the fibonacci function.

LLVMContext Context;

// Create some module to put our function into it.
std::unique_ptr<Module> Owner(new Module("test", Context));
Module *theModule = Owner.get();

// We are about to create the "fib" function:
Function *FibF = CreateFibFunction(M, Context);
errs() << "OK\n";
errs() << "We just constructed this LLVM module:\n\n---------\n";
errs() << *theModule;
errs() << "---------\nstarting fibonacci(" << n << ") with JIT...\n";

Answer 1

You can do it the same way -- instead of using errs(), which is a raw_ostream, you can use a raw_string_ostream, like this:

std::string Str;
raw_string_ostream OS(Str);
OS << *theModule;
OS.flush()
// Str now contains the module text