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60 lines
1.9 KiB
C++
60 lines
1.9 KiB
C++
//===--- GenericMetadataBuilder.h - Math utilities. -------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Utility functions for math operations.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_BASIC_MATH_UTILS_H
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#define SWIFT_BASIC_MATH_UTILS_H
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#include "Compiler.h"
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#include <cstddef>
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#include <cstdint>
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#if SWIFT_COMPILER_IS_MSVC
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#include <intrin.h>
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#endif
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namespace swift {
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/// Round the given value up to the given alignment, as a power of two.
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template <class T>
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static inline constexpr T roundUpToAlignment(T offset, T alignment) {
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return (offset + alignment - 1) & ~(alignment - 1);
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}
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/// Round the given value up to the given alignment, expressed as a mask (a
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/// power of two minus one).
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static inline size_t roundUpToAlignMask(size_t size, size_t alignMask) {
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return (size + alignMask) & ~alignMask;
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}
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static inline unsigned popcount(unsigned value) {
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#if SWIFT_COMPILER_IS_MSVC && (defined(_M_IX86) || defined(_M_X64))
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// The __popcnt intrinsic is only available when targetting x86{_64} with MSVC.
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return __popcnt(value);
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#elif __has_builtin(__builtin_popcount)
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return __builtin_popcount(value);
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#else
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// From llvm/ADT/bit.h which the runtime doesn't have access to (yet?)
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uint32_t v = value;
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v = v - ((v >> 1) & 0x55555555);
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v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
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return int(((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24);
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#endif
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}
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} // namespace swift
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#endif // #ifndef SWIFT_BASIC_MATH_UTILS_H
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