mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2026-01-31 01:35:20 +01:00
0e4d775a3f
Summary: C++14 migration. No functional change. Reviewers: bkramer, JDevlieghere, lebedev.ri Subscribers: MatzeB, hiraditya, jkorous, dexonsmith, arphaman, kadircet, lebedev.ri, usaxena95, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D74384
113 lines
3.7 KiB
C++
113 lines
3.7 KiB
C++
//==-- llvm/Support/CheckedArithmetic.h - Safe arithmetical operations *- 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 contains generic functions for operating on integers which
|
|
// give the indication on whether the operation has overflown.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_SUPPORT_CHECKEDARITHMETIC_H
|
|
#define LLVM_SUPPORT_CHECKEDARITHMETIC_H
|
|
|
|
#include "llvm/ADT/APInt.h"
|
|
#include "llvm/ADT/Optional.h"
|
|
|
|
#include <type_traits>
|
|
|
|
namespace {
|
|
|
|
/// Utility function to apply a given method of \c APInt \p F to \p LHS and
|
|
/// \p RHS.
|
|
/// \return Empty optional if the operation overflows, or result otherwise.
|
|
template <typename T, typename F>
|
|
std::enable_if_t<std::is_integral<T>::value && sizeof(T) * 8 <= 64,
|
|
llvm::Optional<T>>
|
|
checkedOp(T LHS, T RHS, F Op, bool Signed = true) {
|
|
llvm::APInt ALHS(/*BitSize=*/sizeof(T) * 8, LHS, Signed);
|
|
llvm::APInt ARHS(/*BitSize=*/sizeof(T) * 8, RHS, Signed);
|
|
bool Overflow;
|
|
llvm::APInt Out = (ALHS.*Op)(ARHS, Overflow);
|
|
if (Overflow)
|
|
return llvm::None;
|
|
return Signed ? Out.getSExtValue() : Out.getZExtValue();
|
|
}
|
|
}
|
|
|
|
namespace llvm {
|
|
|
|
/// Add two signed integers \p LHS and \p RHS.
|
|
/// \return Optional of sum if no signed overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_signed<T>::value, llvm::Optional<T>>
|
|
checkedAdd(T LHS, T RHS) {
|
|
return checkedOp(LHS, RHS, &llvm::APInt::sadd_ov);
|
|
}
|
|
|
|
/// Subtract two signed integers \p LHS and \p RHS.
|
|
/// \return Optional of sum if no signed overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_signed<T>::value, llvm::Optional<T>>
|
|
checkedSub(T LHS, T RHS) {
|
|
return checkedOp(LHS, RHS, &llvm::APInt::ssub_ov);
|
|
}
|
|
|
|
/// Multiply two signed integers \p LHS and \p RHS.
|
|
/// \return Optional of product if no signed overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_signed<T>::value, llvm::Optional<T>>
|
|
checkedMul(T LHS, T RHS) {
|
|
return checkedOp(LHS, RHS, &llvm::APInt::smul_ov);
|
|
}
|
|
|
|
/// Multiply A and B, and add C to the resulting product.
|
|
/// \return Optional of result if no signed overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_signed<T>::value, llvm::Optional<T>>
|
|
checkedMulAdd(T A, T B, T C) {
|
|
if (auto Product = checkedMul(A, B))
|
|
return checkedAdd(*Product, C);
|
|
return llvm::None;
|
|
}
|
|
|
|
/// Add two unsigned integers \p LHS and \p RHS.
|
|
/// \return Optional of sum if no unsigned overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_unsigned<T>::value, llvm::Optional<T>>
|
|
checkedAddUnsigned(T LHS, T RHS) {
|
|
return checkedOp(LHS, RHS, &llvm::APInt::uadd_ov, /*Signed=*/false);
|
|
}
|
|
|
|
/// Multiply two unsigned integers \p LHS and \p RHS.
|
|
/// \return Optional of product if no unsigned overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_unsigned<T>::value, llvm::Optional<T>>
|
|
checkedMulUnsigned(T LHS, T RHS) {
|
|
return checkedOp(LHS, RHS, &llvm::APInt::umul_ov, /*Signed=*/false);
|
|
}
|
|
|
|
/// Multiply unsigned integers A and B, and add C to the resulting product.
|
|
/// \return Optional of result if no unsigned overflow occurred,
|
|
/// \c None otherwise.
|
|
template <typename T>
|
|
std::enable_if_t<std::is_unsigned<T>::value, llvm::Optional<T>>
|
|
checkedMulAddUnsigned(T A, T B, T C) {
|
|
if (auto Product = checkedMulUnsigned(A, B))
|
|
return checkedAddUnsigned(*Product, C);
|
|
return llvm::None;
|
|
}
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|