llvm/llvm/include/llvm/IR/AbstractCallSite.h

//===- AbstractCallSite.h - Abstract call sites -----------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the AbstractCallSite class, which is a is a wrapper that
// allows treating direct, indirect, and callback calls the same.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_IR_ABSTRACTCALLSITE_H
#define LLVM_IR_ABSTRACTCALLSITE_H

#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Value.h"
#include <cassert>

namespace llvm {

class Argument;
class Use;

/// AbstractCallSite
///
/// An abstract call site is a wrapper that allows to treat direct,
/// indirect, and callback calls the same. If an abstract call site
/// represents a direct or indirect call site it behaves like a stripped
/// down version of a normal call site object. The abstract call site can
/// also represent a callback call, thus the fact that the initially
/// called function (=broker) may invoke a third one (=callback callee).
/// In this case, the abstract call site hides the middle man, hence the
/// broker function. The result is a representation of the callback call,
/// inside the broker, but in the context of the original call to the broker.
///
/// There are up to three functions involved when we talk about callback call
/// sites. The caller (1), which invokes the broker function. The broker
/// function (2), that will invoke the callee zero or more times. And finally
/// the callee (3), which is the target of the callback call.
///
/// The abstract call site will handle the mapping from parameters to arguments
/// depending on the semantic of the broker function. However, it is important
/// to note that the mapping is often partial. Thus, some arguments of the
/// call/invoke instruction are mapped to parameters of the callee while others
/// are not.
class AbstractCallSite { … };

/// Apply function Func to each CB's callback call site.
template <typename UnaryFunction>
void forEachCallbackCallSite(const CallBase &CB, UnaryFunction Func) { … }

/// Apply function Func to each CB's callback function.
template <typename UnaryFunction>
void forEachCallbackFunction(const CallBase &CB, UnaryFunction Func) { … }

} // end namespace llvm

#endif // LLVM_IR_ABSTRACTCALLSITE_H