lib/AST/Interp/Boolean.h

//===--- Boolean.h - Wrapper for boolean types for the 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_BOOLEAN_H
#define LLVM_CLANG_AST_INTERP_BOOLEAN_H

#include <cstddef>
#include <cstdint>
#include "Integral.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ComparisonCategories.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"

namespace clang {
namespace interp {

/// Wrapper around boolean types.
class Boolean {
 private:
  /// Underlying boolean.
  bool V;

  /// Construct a wrapper from a boolean.
  explicit Boolean(bool V) : V(V) {}

 public:
  /// Zero-initializes a boolean.
  Boolean() : V(false) {}

  bool operator<(Boolean RHS) const { return V < RHS.V; }
  bool operator>(Boolean RHS) const { return V > RHS.V; }
  bool operator<=(Boolean RHS) const { return V <= RHS.V; }
  bool operator>=(Boolean RHS) const { return V >= RHS.V; }
  bool operator==(Boolean RHS) const { return V == RHS.V; }
  bool operator!=(Boolean RHS) const { return V != RHS.V; }

  bool operator>(unsigned RHS) const { return static_cast<unsigned>(V) > RHS; }

  Boolean operator-() const { return Boolean(V); }
  Boolean operator~() const { return Boolean(true); }

  explicit operator unsigned() const { return V; }
  explicit operator int64_t() const { return V; }
  explicit operator uint64_t() const { return V; }

  APSInt toAPSInt() const {
    return APSInt(APInt(1, static_cast<uint64_t>(V), false), true);
  }
  APSInt toAPSInt(unsigned NumBits) const {
    return APSInt(toAPSInt().zextOrTrunc(NumBits), true);
  }
  APValue toAPValue() const { return APValue(toAPSInt()); }

  Boolean toUnsigned() const { return *this; }

  constexpr static unsigned bitWidth() { return true; }
  bool isZero() const { return !V; }
  bool isMin() const { return isZero(); }

  constexpr static bool isMinusOne() { return false; }

  constexpr static bool isSigned() { return false; }

  constexpr static bool isNegative() { return false; }
  constexpr static bool isPositive() { return !isNegative(); }

  ComparisonCategoryResult compare(const Boolean &RHS) const {
    return Compare(V, RHS.V);
  }

  unsigned countLeadingZeros() const { return V ? 0 : 1; }

  Boolean truncate(unsigned TruncBits) const { return *this; }

  void print(llvm::raw_ostream &OS) const { OS << (V ? "true" : "false"); }

  static Boolean min(unsigned NumBits) { return Boolean(false); }
  static Boolean max(unsigned NumBits) { return Boolean(true); }

  template <typename T>
  static typename std::enable_if<std::is_integral<T>::value, Boolean>::type
  from(T Value) {
    return Boolean(Value != 0);
  }

  template <unsigned SrcBits, bool SrcSign>
  static typename std::enable_if<SrcBits != 0, Boolean>::type from(
      Integral<SrcBits, SrcSign> Value) {
    return Boolean(!Value.isZero());
  }

  template <bool SrcSign>
  static Boolean from(Integral<0, SrcSign> Value) {
    return Boolean(!Value.isZero());
  }

  static Boolean zero() { return from(false); }

  template <typename T>
  static Boolean from(T Value, unsigned NumBits) {
    return Boolean(Value);
  }

  static bool inRange(int64_t Value, unsigned NumBits) {
    return Value == 0 || Value == 1;
  }

  static bool increment(Boolean A, Boolean *R) {
    *R = Boolean(true);
    return false;
  }

  static bool decrement(Boolean A, Boolean *R) {
    llvm_unreachable("Cannot decrement booleans");
  }

  static bool add(Boolean A, Boolean B, unsigned OpBits, Boolean *R) {
    *R = Boolean(A.V || B.V);
    return false;
  }

  static bool sub(Boolean A, Boolean B, unsigned OpBits, Boolean *R) {
    *R = Boolean(A.V ^ B.V);
    return false;
  }

  static bool mul(Boolean A, Boolean B, unsigned OpBits, Boolean *R) {
    *R = Boolean(A.V && B.V);
    return false;
  }
};

inline llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Boolean &B) {
  B.print(OS);
  return OS;
}

}  // namespace interp
}  // namespace clang

#endif