mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
48aa75d86f
In the prior implementation of runtime resolution of isolated conformances, the runtime had to look in both the protocol conformance descriptor and in all conditional conformance requirements (recursively) to find any isolated conformances. If it found one, it had to demangle the global actor type to metadata. Since swift_conformsToProtocol is a hot path through the runtime, we can't afford this non-constant-time work in the common case. Instead, cache the resolved global actor and witness table as part of the conformance cache, so that we have access to this information every time we look up a witness table for a conformance. Propagate this up through various callers (e.g., generic requirement checking) to the point where we either stash it in the cache or check it at runtime. This gets us down to a very quick check (basically, NULL-or-not) for nonisolated conformances, and just one check for isolated conformances.
278 lines
11 KiB
C++
278 lines
11 KiB
C++
//===--- Casting.h - Swift type-casting runtime support ---------*- C++ -*-===//
|
|
//
|
|
// This source file is part of the Swift.org open source project
|
|
//
|
|
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
|
|
// Licensed under Apache License v2.0 with Runtime Library Exception
|
|
//
|
|
// See https://swift.org/LICENSE.txt for license information
|
|
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Swift runtime functions for casting values.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef SWIFT_RUNTIME_CASTING_H
|
|
#define SWIFT_RUNTIME_CASTING_H
|
|
|
|
#include "swift/Runtime/Metadata.h"
|
|
|
|
namespace swift {
|
|
|
|
/// Perform a checked dynamic cast of a value to a target type.
|
|
///
|
|
/// \param dest A buffer into which to write the destination value.
|
|
/// In all cases, this will be left uninitialized if the cast fails.
|
|
///
|
|
/// \param src Pointer to the source value to cast. This may be left
|
|
/// uninitialized after the operation, depending on the flags.
|
|
///
|
|
/// \param targetType The type to which we are casting.
|
|
///
|
|
/// \param srcType The static type of the source value.
|
|
///
|
|
/// \param flags Flags to control the operation.
|
|
///
|
|
/// \return true if the cast succeeded. Depending on the flags,
|
|
/// swift_dynamicCast may fail rather than return false.
|
|
SWIFT_RUNTIME_EXPORT
|
|
bool
|
|
swift_dynamicCast(OpaqueValue *dest, OpaqueValue *src,
|
|
const Metadata *srcType,
|
|
const Metadata *targetType,
|
|
DynamicCastFlags flags);
|
|
|
|
/// Checked dynamic cast to a Swift class type.
|
|
///
|
|
/// \param object The object to cast.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a Swift class type.
|
|
///
|
|
/// \returns the object if the cast succeeds, or null otherwise.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastClass(const void *object, const ClassMetadata *targetType);
|
|
|
|
/// Unconditional, checked dynamic cast to a Swift class type.
|
|
///
|
|
/// Aborts if the object isn't of the target type.
|
|
///
|
|
/// \param object The object to cast.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a Swift class type.
|
|
/// \param file The source filename from which to report failure. May be null.
|
|
/// \param line The source line from which to report failure.
|
|
/// \param column The source column from which to report failure.
|
|
///
|
|
/// \returns the object.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastClassUnconditional(const void *object,
|
|
const ClassMetadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
|
|
#if SWIFT_OBJC_INTEROP
|
|
/// Checked Objective-C-style dynamic cast to a class type.
|
|
///
|
|
/// \param object The object to cast, or nil.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a class type, but not necessarily valid type metadata.
|
|
///
|
|
/// \returns the object if the cast succeeds, or null otherwise.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastObjCClass(const void *object, const ClassMetadata *targetType);
|
|
|
|
/// Checked dynamic cast to a foreign class type.
|
|
///
|
|
/// \param object The object to cast, or nil.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a foreign class type.
|
|
///
|
|
/// \returns the object if the cast succeeds, or null otherwise.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastForeignClass(const void *object,
|
|
const ForeignClassMetadata *targetType);
|
|
|
|
/// Unconditional, checked, Objective-C-style dynamic cast to a class
|
|
/// type.
|
|
///
|
|
/// Aborts if the object isn't of the target type.
|
|
/// Note that unlike swift_dynamicCastClassUnconditional, this does not abort
|
|
/// if the object is 'nil'.
|
|
///
|
|
/// \param object The object to cast, or nil.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a class type, but not necessarily valid type metadata.
|
|
/// \param file The source filename from which to report failure. May be null.
|
|
/// \param line The source line from which to report failure.
|
|
/// \param column The source column from which to report failure.
|
|
///
|
|
/// \returns the object.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastObjCClassUnconditional(const void *object,
|
|
const ClassMetadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
|
|
/// Unconditional, checked dynamic cast to a foreign class type.
|
|
///
|
|
/// \param object The object to cast, or nil.
|
|
/// \param targetType The type to which we are casting, which is known to be
|
|
/// a foreign class type.
|
|
/// \param file The source filename from which to report failure. May be null.
|
|
/// \param line The source line from which to report failure.
|
|
/// \param column The source column from which to report failure.
|
|
///
|
|
/// \returns the object if the cast succeeds, or null otherwise.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastForeignClassUnconditional(
|
|
const void *object,
|
|
const ForeignClassMetadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
#endif
|
|
|
|
/// Checked dynamic cast of a class instance pointer to the given type.
|
|
///
|
|
/// \param object The class instance to cast.
|
|
///
|
|
/// \param targetType The type to which we are casting, which may be either a
|
|
/// class type or a wrapped Objective-C class type.
|
|
///
|
|
/// \returns the object, or null if it doesn't have the given target type.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastUnknownClass(const void *object, const Metadata *targetType);
|
|
|
|
/// Unconditional checked dynamic cast of a class instance pointer to
|
|
/// the given type.
|
|
///
|
|
/// Aborts if the object isn't of the target type.
|
|
///
|
|
/// \param object The class instance to cast.
|
|
///
|
|
/// \param targetType The type to which we are casting, which may be either a
|
|
/// class type or a wrapped Objective-C class type.
|
|
///
|
|
/// \param file The source filename from which to report failure. May be null.
|
|
/// \param line The source line from which to report failure.
|
|
/// \param column The source column from which to report failure.
|
|
///
|
|
/// \returns the object.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const void *
|
|
swift_dynamicCastUnknownClassUnconditional(const void *object,
|
|
const Metadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
|
|
SWIFT_RUNTIME_EXPORT
|
|
const Metadata *
|
|
swift_dynamicCastMetatype(const Metadata *sourceType,
|
|
const Metadata *targetType);
|
|
SWIFT_RUNTIME_EXPORT
|
|
const Metadata *
|
|
swift_dynamicCastMetatypeUnconditional(const Metadata *sourceType,
|
|
const Metadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
#if SWIFT_OBJC_INTEROP
|
|
SWIFT_RUNTIME_EXPORT
|
|
const ClassMetadata *
|
|
swift_dynamicCastObjCClassMetatype(const ClassMetadata *sourceType,
|
|
const ClassMetadata *targetType);
|
|
SWIFT_RUNTIME_EXPORT
|
|
const ClassMetadata *
|
|
swift_dynamicCastObjCClassMetatypeUnconditional(const ClassMetadata *sourceType,
|
|
const ClassMetadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
#endif
|
|
|
|
SWIFT_RUNTIME_EXPORT
|
|
const ClassMetadata *
|
|
swift_dynamicCastForeignClassMetatype(const ClassMetadata *sourceType,
|
|
const ClassMetadata *targetType);
|
|
SWIFT_RUNTIME_EXPORT
|
|
const ClassMetadata *
|
|
swift_dynamicCastForeignClassMetatypeUnconditional(
|
|
const ClassMetadata *sourceType,
|
|
const ClassMetadata *targetType,
|
|
const char *file, unsigned line, unsigned column);
|
|
|
|
/// Return the dynamic type of an opaque value.
|
|
///
|
|
/// \param value An opaque value.
|
|
/// \param self The static type metadata for the opaque value and the result
|
|
/// type value.
|
|
/// \param existentialMetatype Whether the result type value is an existential
|
|
/// metatype. If `self` is an existential type,
|
|
/// then a `false` value indicates that the result
|
|
/// is of concrete metatype type `self.Protocol`,
|
|
/// and existential containers will not be projected
|
|
/// through. A `true` value indicates that the result
|
|
/// is of existential metatype type `self.Type`,
|
|
/// so existential containers can be projected
|
|
/// through as long as a subtype relationship holds
|
|
/// from `self` to the contained dynamic type.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const Metadata *
|
|
swift_getDynamicType(OpaqueValue *value, const Metadata *self,
|
|
bool existentialMetatype);
|
|
|
|
/// Fetch the type metadata associated with the formal dynamic
|
|
/// type of the given (possibly Objective-C) object. The formal
|
|
/// dynamic type ignores dynamic subclasses such as those introduced
|
|
/// by KVO. See [NOTE: Dynamic-subclass-KVO]
|
|
///
|
|
/// The object pointer may be a tagged pointer, but cannot be null.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const Metadata *swift_getObjectType(HeapObject *object);
|
|
|
|
/// Check whether a type conforms to a given native Swift protocol,
|
|
/// visible from the named module.
|
|
///
|
|
/// If so, returns a pointer to the witness table for its conformance.
|
|
/// Returns void if the type does not conform to the protocol.
|
|
///
|
|
/// \param type The metadata for the type for which to do the conformance
|
|
/// check.
|
|
/// \param protocol The protocol descriptor for the protocol to check
|
|
/// conformance for. This pointer does not have ptrauth applied.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const WitnessTable *swift_conformsToProtocol(const Metadata *type,
|
|
const void *protocol);
|
|
|
|
/// Check whether a type conforms to a given native Swift protocol. Identical to
|
|
/// swift_conformsToProtocol, except that the protocol parameter has a ptrauth
|
|
/// signature on ARM64e that is signed with a process independent key.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const WitnessTable *
|
|
swift_conformsToProtocol2(const Metadata *type,
|
|
const ProtocolDescriptor *protocol);
|
|
|
|
/// Check whether a type conforms to a given native Swift protocol. Identical to
|
|
/// swift_conformsToProtocol, except that the protocol parameter has a ptrauth
|
|
/// signature on ARM64e that is signed with a process dependent key.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const WitnessTable *
|
|
swift_conformsToProtocolCommon(const Metadata *type,
|
|
const ProtocolDescriptor *protocol);
|
|
|
|
/// Check whether a type conforms to a given native Swift protocol. This
|
|
/// is similar to swift_conformsToProtocolCommon, but allows the caller to
|
|
/// capture the global actor isolation of the conformance rather than
|
|
/// checking that the code is currently executing on that global actor.
|
|
SWIFT_RUNTIME_EXPORT
|
|
const WitnessTable *
|
|
swift_conformsToProtocolCommonIsolated(
|
|
const Metadata *type,
|
|
const ProtocolDescriptor *protocol,
|
|
const Metadata **globalActorIsolationType,
|
|
const WitnessTable **globalActorIsolationWitnessTable);
|
|
|
|
} // end namespace swift
|
|
|
|
#endif // SWIFT_RUNTIME_CASTING_H
|