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137 lines
6.4 KiB
C++
137 lines
6.4 KiB
C++
//===--- CompatibiltyOverride.h - Back-deploying compatibility fixes --*- 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 - 2018 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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// Support back-deploying compatibility fixes for newer apps running on older runtimes.
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//
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//===----------------------------------------------------------------------===//
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#ifndef COMPATIBILITY_OVERRIDE_H
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#define COMPATIBILITY_OVERRIDE_H
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#include "../runtime/Private.h"
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#include "swift/Runtime/Concurrency.h"
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#include "swift/Runtime/Metadata.h"
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#include "swift/Runtime/Once.h"
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#include <type_traits>
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namespace swift {
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// Macro utilities.
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#define COMPATIBILITY_UNPAREN(...) __VA_ARGS__
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#define COMPATIBILITY_CONCAT2(x, y) x##y
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#define COMPATIBILITY_CONCAT(x, y) COMPATIBILITY_CONCAT2(x, y)
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// This ridiculous construct will remove the parentheses from the argument and
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// add a trailing comma, or will produce nothing when passed no argument. For
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// example:
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// COMPATIBILITY_UNPAREN_WITH_COMMA((1, 2, 3)) -> 1, 2, 3,
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// COMPATIBILITY_UNPAREN_WITH_COMMA((4)) -> 4,
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// COMPATIBILITY_UNPAREN_WITH_COMMA() ->
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#define COMPATIBILITY_UNPAREN_WITH_COMMA(x) \
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COMPATIBILITY_CONCAT(COMPATIBILITY_UNPAREN_ADD_TRAILING_COMMA_, \
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COMPATIBILITY_UNPAREN_WITH_COMMA2 x)
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#define COMPATIBILITY_UNPAREN_WITH_COMMA2(...) PARAMS(__VA_ARGS__)
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#define COMPATIBILITY_UNPAREN_ADD_TRAILING_COMMA_PARAMS(...) __VA_ARGS__,
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#define COMPATIBILITY_UNPAREN_ADD_TRAILING_COMMA_COMPATIBILITY_UNPAREN_WITH_COMMA2
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// This ridiculous construct will preserve the parentheses around the argument,
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// or will produce an empty pair of parentheses when passed no argument. For
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// example:
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// COMPATIBILITY_PAREN((1, 2, 3)) -> (1, 2, 3)
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// COMPATIBILITY_PAREN((4)) -> (4)
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// COMPATIBILITY_PAREN() -> ()
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#define COMPATIBILITY_PAREN(x) \
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COMPATIBILITY_CONCAT(COMPATIBILITY_PAREN_, COMPATIBILITY_PAREN2 x)
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#define COMPATIBILITY_PAREN2(...) PARAMS(__VA_ARGS__)
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#define COMPATIBILITY_PAREN_PARAMS(...) (__VA_ARGS__)
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#define COMPATIBILITY_PAREN_COMPATIBILITY_PAREN2 ()
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// Include path computation. Code that includes this file can write
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// `#include COMPATIBILITY_OVERRIDE_INCLUDE_PATH` to include the appropriate
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// .def file for the current library.
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#define COMPATIBILITY_OVERRIDE_INCLUDE_PATH_swiftRuntime \
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"../CompatibilityOverride/CompatibilityOverrideRuntime.def"
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#define COMPATIBILITY_OVERRIDE_INCLUDE_PATH_swift_Concurrency \
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"../CompatibilityOverride/CompatibilityOverrideConcurrency.def"
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#define COMPATIBILITY_OVERRIDE_INCLUDE_PATH \
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COMPATIBILITY_CONCAT(COMPATIBILITY_OVERRIDE_INCLUDE_PATH_, \
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SWIFT_TARGET_LIBRARY_NAME)
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// Compatibility overrides are only supported on Darwin.
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#ifdef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
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#if !(defined(__APPLE__) && defined(__MACH__))
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#undef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
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#endif
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#endif
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#ifndef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
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// Call directly through to the original implementation when we don't support
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// overrides.
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#define COMPATIBILITY_OVERRIDE(name, ret, attrs, ccAttrs, namespace, \
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typedArgs, namedArgs) \
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attrs ccAttrs ret namespace swift_##name COMPATIBILITY_PAREN(typedArgs) { \
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return swift_##name##Impl COMPATIBILITY_PAREN(namedArgs); \
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}
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#else // #ifndef SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
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// Override section name computation. `COMPATIBILITY_OVERRIDE_SECTION_NAME` will
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// resolve to string literal containing the appropriate section name for the
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// current library.
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#define COMPATIBILITY_OVERRIDE_SECTION_NAME_swiftRuntime "__swift56_hooks"
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#define COMPATIBILITY_OVERRIDE_SECTION_NAME_swift_Concurrency "__s_async_hook"
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#define COMPATIBILITY_OVERRIDE_SECTION_NAME \
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COMPATIBILITY_CONCAT(COMPATIBILITY_OVERRIDE_SECTION_NAME_, \
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SWIFT_TARGET_LIBRARY_NAME)
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// Create typedefs for function pointers to call the original implementation.
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#define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
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ccAttrs typedef ret(*Original_##name) COMPATIBILITY_PAREN(typedArgs);
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#include COMPATIBILITY_OVERRIDE_INCLUDE_PATH
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// Create typedefs for override function pointers.
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#define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
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ccAttrs typedef ret (*Override_##name)(COMPATIBILITY_UNPAREN_WITH_COMMA( \
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typedArgs) Original_##name originalImpl);
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#include COMPATIBILITY_OVERRIDE_INCLUDE_PATH
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// Create declarations for getOverride functions.
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#define OVERRIDE(name, ret, attrs, ccAttrs, namespace, typedArgs, namedArgs) \
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Override_ ## name getOverride_ ## name();
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#include COMPATIBILITY_OVERRIDE_INCLUDE_PATH
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/// Used to define an override point. The override point #defines the appropriate
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/// OVERRIDE macro from CompatibilityOverride.def to this macro, then includes
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/// the file to generate the override points. The original implementation of the
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/// functionality must be available as swift_funcNameHereImpl.
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#define COMPATIBILITY_OVERRIDE(name, ret, attrs, ccAttrs, namespace, \
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typedArgs, namedArgs) \
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attrs ccAttrs ret namespace swift_##name COMPATIBILITY_PAREN(typedArgs) { \
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static Override_##name Override; \
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static swift_once_t Predicate; \
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swift_once( \
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&Predicate, [](void *) { Override = getOverride_##name(); }, nullptr); \
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if (Override != nullptr) \
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return Override(COMPATIBILITY_UNPAREN_WITH_COMMA(namedArgs) \
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swift_##name##Impl); \
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return swift_##name##Impl COMPATIBILITY_PAREN(namedArgs); \
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}
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#endif // #else SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT
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} /* end namespace swift */
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#endif /* COMPATIBILITY_OVERRIDE_H */
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