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41 lines
1.5 KiB
Swift
41 lines
1.5 KiB
Swift
//===--- AssumeSingleThreaded.swift - Assume single-threaded execution ----===//
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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 - 2022 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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// Assume that user code is single-threaded.
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//
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// Convert all reference counting operations into non-atomic ones.
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//
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// To get rid of most atomic reference counting operations, the standard
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// library should be compiled in this mode as well .
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//
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// This pass affects only reference counting operations resulting from SIL
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// instructions. It wouldn't affect places in the runtime C++ code which
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// hard-code calls to retain/release. We could take advantage of the Instruments
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// instrumentation stubs to redirect calls from the runtime if it was
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// significant, or else just build a single-threaded variant of the runtime.
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//
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//===----------------------------------------------------------------------===//
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import SIL
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let assumeSingleThreadedPass = FunctionPass(
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name: "sil-assume-single-threaded", { function, context in
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for block in function.blocks {
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for inst in block.instructions {
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guard let rcInst = inst as? RefCountingInst else { continue }
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context.setAtomicity(of: rcInst, isAtomic: false)
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}
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}
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}
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)
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