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53 lines
1.4 KiB
C++
53 lines
1.4 KiB
C++
//===--- BCReadingExtras.h - Useful helpers for bitcode reading -*- 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 - 2017 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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#ifndef SWIFT_SERIALIZATION_BCREADINGEXTRAS_H
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#define SWIFT_SERIALIZATION_BCREADINGEXTRAS_H
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#include "llvm/Bitstream/BitstreamReader.h"
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namespace swift {
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namespace serialization {
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/// Saves and restores a BitstreamCursor's bit offset in its stream.
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class BCOffsetRAII {
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llvm::BitstreamCursor *Cursor;
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decltype(Cursor->GetCurrentBitNo()) Offset;
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public:
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explicit BCOffsetRAII(llvm::BitstreamCursor &cursor)
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: Cursor(&cursor), Offset(cursor.GetCurrentBitNo()) {}
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void reset() {
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if (Cursor)
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Offset = Cursor->GetCurrentBitNo();
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}
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void cancel() {
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Cursor = nullptr;
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}
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~BCOffsetRAII() {
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if (Cursor)
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cantFail(Cursor->JumpToBit(Offset),
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"BCOffsetRAII must be able to go back");
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}
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};
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} // end namespace serialization
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} // end namespace swift
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static constexpr const auto AF_DontPopBlockAtEnd =
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llvm::BitstreamCursor::AF_DontPopBlockAtEnd;
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#endif
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