llvm-project/clang/lib/AST/Interp/FunctionPointer.h

//===--- FunctionPointer.h - Types for the constexpr VM ---------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_INTERP_FUNCTION_POINTER_H
#define LLVM_CLANG_AST_INTERP_FUNCTION_POINTER_H

#include "Function.h"
#include "Primitives.h"
#include "clang/AST/APValue.h"

namespace clang {
class ASTContext;
namespace interp {

class FunctionPointer final {
private:
  const Function *Func;

public:
  // FIXME: We might want to track the fact that the Function pointer
  // has been created from an integer and is most likely garbage anyway.
  FunctionPointer(uintptr_t IntVal = 0, const Descriptor *Desc = nullptr)
      : Func(reinterpret_cast<const Function *>(IntVal)) {}

  FunctionPointer(const Function *Func) : Func(Func) { assert(Func); }

  const Function *getFunction() const { return Func; }
  bool isZero() const { return !Func; }

  APValue toAPValue() const {
    if (!Func)
      return APValue(static_cast<Expr *>(nullptr), CharUnits::Zero(), {},
                     /*OnePastTheEnd=*/false, /*IsNull=*/true);

    return APValue(Func->getDecl(), CharUnits::Zero(), {},
                   /*OnePastTheEnd=*/false, /*IsNull=*/false);
  }

  void print(llvm::raw_ostream &OS) const {
    OS << "FnPtr(";
    if (Func)
      OS << Func->getName();
    else
      OS << "nullptr";
    OS << ")";
  }

  std::string toDiagnosticString(const ASTContext &Ctx) const {
    if (!Func)
      return "nullptr";

    return toAPValue().getAsString(Ctx, Func->getDecl()->getType());
  }

  uint64_t getIntegerRepresentation() const {
    return static_cast<uint64_t>(reinterpret_cast<uintptr_t>(Func));
  }

  ComparisonCategoryResult compare(const FunctionPointer &RHS) const {
    if (Func == RHS.Func)
      return ComparisonCategoryResult::Equal;
    return ComparisonCategoryResult::Unordered;
  }
};

inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS,
                                     FunctionPointer FP) {
  FP.print(OS);
  return OS;
}

} // namespace interp
} // namespace clang

#endif