Method getOrInsertFunction

src/lib/IR/Module.cpp:144–166

getOrInsertFunction - Look up the specified function in the module symbol table. If it does not exist, add a prototype for the function and return it. This is nice because it allows most passes to get away with not handling the symbol table directly for this common task.

// the symbol table directly for this common task.
//
Constant *Module::getOrInsertFunction(StringRef Name, FunctionType *Ty,
                                      AttributeList AttributeList) {
  // See if we have a definition for the specified function already.
  GlobalValue *F = getNamedValue(Name);
  if (!F) {
    // Nope, add it
    Function *New = Function::Create(Ty, GlobalVariable::ExternalLinkage,
                                     DL.getProgramAddressSpace(), Name);
    if (!New->isIntrinsic())       // Intrinsics get attrs set on construction
      New->setAttributes(AttributeList);
    FunctionList.push_back(New);
    return New;                    // Return the new prototype.
  }

  // If the function exists but has the wrong type, return a bitcast to the
  // right type.
  auto *PTy = PointerType::get(Ty, F->getAddressSpace());
  if (F->getType() != PTy)
    return ConstantExpr::getBitCast(F, PTy);

  // Otherwise, we just found the existing function or a prototype.
  return F;
}

Constant *Module::getOrInsertFunction(StringRef Name,
                                      FunctionType *Ty) {