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fe7e13bba5
Ensure that context descriptor pointers are signed in the runtime by putting the ptrauth_struct attribute on the types. We use the new __builtin_ptrauth_struct_key/disc to conditionally apply ptrauth_struct to TrailingObjects based on the signing of the base type, so that pointers to TrailingObjects get signed when used with a context descriptor pointer. We add new runtime entrypoints that take signed pointers where appropriate, and have the compiler emit calls to the new entrypoints when targeting a sufficiently new OS. rdar://111480914
1632 lines
63 KiB
C++
1632 lines
63 KiB
C++
//===--- ProtocolConformance.cpp - Swift protocol conformance checking ----===//
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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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//
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// Checking and caching of Swift protocol conformances.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/StringExtras.h"
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#include "swift/ABI/TypeIdentity.h"
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#include "swift/Basic/Lazy.h"
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#include "swift/Basic/STLExtras.h"
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#include "swift/Demangling/Demangle.h"
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#include "swift/Runtime/Bincompat.h"
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#include "swift/Runtime/Casting.h"
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#include "swift/Runtime/Concurrent.h"
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#include "swift/Runtime/EnvironmentVariables.h"
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#include "swift/Runtime/HeapObject.h"
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#include "swift/Runtime/Metadata.h"
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#include "swift/Basic/Unreachable.h"
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#include "llvm/ADT/DenseMap.h"
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#include "../CompatibilityOverride/CompatibilityOverride.h"
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#include "ImageInspection.h"
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#include "Private.h"
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#include "Tracing.h"
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#include <new>
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#include <vector>
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#if __has_include(<mach-o/dyld_priv.h>)
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#include <mach-o/dyld_priv.h>
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#define DYLD_EXPECTED_SWIFT_OPTIMIZATIONS_VERSION 1u
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// Redeclare these functions as weak so we can build against a macOS 12 SDK and
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// still test on macOS 11.
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LLVM_ATTRIBUTE_WEAK
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struct _dyld_protocol_conformance_result
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_dyld_find_protocol_conformance(const void *protocolDescriptor,
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const void *metadataType,
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const void *typeDescriptor);
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LLVM_ATTRIBUTE_WEAK
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struct _dyld_protocol_conformance_result
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_dyld_find_foreign_type_protocol_conformance(const void *protocol,
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const char *foreignTypeIdentityStart,
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size_t foreignTypeIdentityLength);
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LLVM_ATTRIBUTE_WEAK
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uint32_t _dyld_swift_optimizations_version(void);
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#if DYLD_FIND_PROTOCOL_ON_DISK_CONFORMANCE_DEFINED
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// Redeclare these functions as weak as well.
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LLVM_ATTRIBUTE_WEAK bool _dyld_has_preoptimized_swift_protocol_conformances(
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const struct mach_header *mh);
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LLVM_ATTRIBUTE_WEAK struct _dyld_protocol_conformance_result
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_dyld_find_protocol_conformance_on_disk(const void *protocolDescriptor,
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const void *metadataType,
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const void *typeDescriptor,
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uint32_t flags);
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LLVM_ATTRIBUTE_WEAK struct _dyld_protocol_conformance_result
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_dyld_find_foreign_type_protocol_conformance_on_disk(
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const void *protocol, const char *foreignTypeIdentityStart,
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size_t foreignTypeIdentityLength, uint32_t flags);
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#endif // DYLD_FIND_PROTOCOL_ON_DISK_CONFORMANCE_DEFINED
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#endif // __has_include(<mach-o/dyld_priv.h>)
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// Set this to 1 to enable logging of calls to the dyld shared cache conformance
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// table
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#if 0
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#define DYLD_CONFORMANCES_LOG(fmt, ...) \
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fprintf(stderr, "PROTOCOL CONFORMANCE: " fmt "\n", __VA_ARGS__)
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#define SHARED_CACHE_LOG_ENABLED 1
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#else
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#define DYLD_CONFORMANCES_LOG(fmt, ...) (void)0
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#endif
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// Enable dyld shared cache acceleration only when it's available and we have
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// ObjC interop.
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#if DYLD_FIND_PROTOCOL_CONFORMANCE_DEFINED && SWIFT_OBJC_INTEROP
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#define USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES 1
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#endif
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using namespace swift;
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#ifndef NDEBUG
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template <> SWIFT_USED void ProtocolDescriptor::dump() const {
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printf("TargetProtocolDescriptor.\n"
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"Name: \"%s\".\n",
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Name.get());
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}
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void ProtocolDescriptorFlags::dump() const {
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printf("ProtocolDescriptorFlags.\n");
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printf("Is Swift: %s.\n", (isSwift() ? "true" : "false"));
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printf("Needs Witness Table: %s.\n",
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(needsWitnessTable() ? "true" : "false"));
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printf("Is Resilient: %s.\n", (isResilient() ? "true" : "false"));
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printf("Special Protocol: %s.\n",
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(bool(getSpecialProtocol()) ? "Error" : "None"));
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printf("Class Constraint: %s.\n",
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(bool(getClassConstraint()) ? "Class" : "Any"));
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printf("Dispatch Strategy: %s.\n",
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(bool(getDispatchStrategy()) ? "Swift" : "ObjC"));
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}
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#endif
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#if !defined(NDEBUG) && SWIFT_OBJC_INTEROP
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#include <objc/runtime.h>
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static const char *class_getName(const ClassMetadata* type) {
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return class_getName(
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reinterpret_cast<Class>(const_cast<ClassMetadata*>(type)));
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}
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template<> void ProtocolConformanceDescriptor::dump() const {
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llvm::Optional<SymbolInfo> info;
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auto symbolName = [&](const void *addr) -> const char * {
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info = SymbolInfo::lookup(addr);
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if (info.has_value() && info->getSymbolName()) {
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return info->getSymbolName();
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}
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return "<unknown addr>";
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};
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switch (auto kind = getTypeKind()) {
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case TypeReferenceKind::DirectObjCClassName:
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printf("direct Objective-C class name %s", getDirectObjCClassName());
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break;
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case TypeReferenceKind::IndirectObjCClass:
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printf("indirect Objective-C class %s",
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class_getName(*getIndirectObjCClass()));
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break;
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case TypeReferenceKind::DirectTypeDescriptor:
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case TypeReferenceKind::IndirectTypeDescriptor:
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printf("unique nominal type descriptor %s", symbolName(getTypeDescriptor()));
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break;
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}
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printf(" => ");
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printf("witness table pattern (%p) %s\n", getWitnessTablePattern(), symbolName(getWitnessTablePattern()));
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}
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#endif
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#ifndef NDEBUG
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template <> SWIFT_USED void ProtocolConformanceDescriptor::verify() const {
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auto typeKind = unsigned(getTypeKind());
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assert(((unsigned(TypeReferenceKind::First_Kind) <= typeKind) &&
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(unsigned(TypeReferenceKind::Last_Kind) >= typeKind)) &&
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"Corrupted type metadata record kind");
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}
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#endif
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#if SWIFT_OBJC_INTEROP
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template <>
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const ClassMetadata *TypeReference::getObjCClass(TypeReferenceKind kind) const {
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switch (kind) {
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case TypeReferenceKind::IndirectObjCClass:
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return *getIndirectObjCClass(kind);
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case TypeReferenceKind::DirectObjCClassName:
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return reinterpret_cast<const ClassMetadata *>(
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objc_lookUpClass(getDirectObjCClassName(kind)));
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case TypeReferenceKind::DirectTypeDescriptor:
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case TypeReferenceKind::IndirectTypeDescriptor:
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return nullptr;
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}
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swift_unreachable("Unhandled TypeReferenceKind in switch.");
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}
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#endif
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static MetadataState
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tryGetCompleteMetadataNonblocking(const Metadata *metadata) {
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return swift_checkMetadataState(
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MetadataRequest(MetadataState::Complete, /*isNonBlocking*/ true),
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metadata)
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.State;
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}
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/// Get the superclass of metadata, which may be incomplete. When the metadata
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/// is not sufficiently complete, then we fall back to demangling the superclass
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/// in the nominal type descriptor, which is slow but works. Return {NULL,
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/// MetadataState::Complete} if the metadata is not a class, or has no
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/// superclass.
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///
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/// If the metadata's current state is known, it may be passed in as
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/// knownMetadataState. This saves the cost of retrieving that info separately.
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///
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/// When instantiateSuperclassMetadata is true, this function will instantiate
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/// superclass metadata when necessary. When false, this will return {NULL,
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/// MetadataState::Abstract} to indicate that there's an uninstantiated
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/// superclass that was not returned.
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static MetadataResponse getSuperclassForMaybeIncompleteMetadata(
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const Metadata *metadata, llvm::Optional<MetadataState> knownMetadataState,
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bool instantiateSuperclassMetadata) {
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const ClassMetadata *classMetadata = dyn_cast<ClassMetadata>(metadata);
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if (!classMetadata)
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return {_swift_class_getSuperclass(metadata), MetadataState::Complete};
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#if SWIFT_OBJC_INTEROP
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// Artificial subclasses are not valid type metadata and
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// tryGetCompleteMetadataNonblocking will crash on them. However, they're
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// always fully set up, so we can just skip it and fetch the Subclass field.
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if (classMetadata->isTypeMetadata() && classMetadata->isArtificialSubclass())
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return {classMetadata->Superclass, MetadataState::Complete};
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// Pure ObjC classes are already set up, and the code below will not be
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// happy with them.
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if (!classMetadata->isTypeMetadata())
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return {classMetadata->Superclass, MetadataState::Complete};
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#endif
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MetadataState metadataState;
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if (knownMetadataState)
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metadataState = *knownMetadataState;
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else
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metadataState = tryGetCompleteMetadataNonblocking(classMetadata);
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if (metadataState == MetadataState::Complete) {
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// The subclass metadata is complete. Fetch and return the superclass.
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auto *superMetadata = getMetadataForClass(classMetadata->Superclass);
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return {superMetadata, MetadataState::Complete};
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} else if (metadataState == MetadataState::NonTransitiveComplete) {
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// The subclass metadata is complete, but, unlike above, not transitively.
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// Its Superclass field is valid, so just read that field to get to the
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// superclass to proceed to the next step.
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auto *superMetadata = getMetadataForClass(classMetadata->Superclass);
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auto superState = tryGetCompleteMetadataNonblocking(superMetadata);
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return {superMetadata, superState};
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} else if (instantiateSuperclassMetadata) {
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// The subclass metadata is either LayoutComplete or Abstract, so the
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// Superclass field is not valid. To get to the superclass, make the
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// expensive call to getSuperclassMetadata which demangles the superclass
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// name from the nominal type descriptor to get the metadata for the
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// superclass.
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MetadataRequest request(MetadataState::Abstract,
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/*non-blocking*/ true);
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return getSuperclassMetadata(request, classMetadata);
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} else {
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// The Superclass field is not valid and the caller did not request
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// instantiation. Return a NULL superclass and Abstract to indicate that a
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// superclass exists but is not yet instantiated.
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return {nullptr, MetadataState::Abstract};
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}
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}
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struct MaybeIncompleteSuperclassIterator {
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const Metadata *metadata;
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llvm::Optional<MetadataState> state;
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bool instantiateSuperclassMetadata;
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MaybeIncompleteSuperclassIterator(const Metadata *metadata,
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bool instantiateSuperclassMetadata)
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: metadata(metadata), state(llvm::None),
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instantiateSuperclassMetadata(instantiateSuperclassMetadata) {}
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MaybeIncompleteSuperclassIterator &operator++() {
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auto response = getSuperclassForMaybeIncompleteMetadata(
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metadata, state, instantiateSuperclassMetadata);
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metadata = response.Value;
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state = response.State;
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return *this;
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}
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const Metadata *operator*() const { return metadata; }
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bool operator!=(const MaybeIncompleteSuperclassIterator rhs) const {
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return metadata != rhs.metadata;
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}
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};
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/// Take the type reference inside a protocol conformance record and fetch the
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/// canonical metadata pointer for the type it refers to.
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/// Returns nil for universal or generic type references.
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template <>
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const Metadata *
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ProtocolConformanceDescriptor::getCanonicalTypeMetadata() const {
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switch (getTypeKind()) {
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case TypeReferenceKind::IndirectObjCClass:
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case TypeReferenceKind::DirectObjCClassName:
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#if SWIFT_OBJC_INTEROP
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// The class may be ObjC, in which case we need to instantiate its Swift
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// metadata. The class additionally may be weak-linked, so we have to check
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// for null.
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if (auto cls = TypeRef.getObjCClass(getTypeKind()))
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return getMetadataForClass(cls);
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#endif
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return nullptr;
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case TypeReferenceKind::DirectTypeDescriptor:
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case TypeReferenceKind::IndirectTypeDescriptor: {
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if (auto anyType = getTypeDescriptor()) {
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if (auto type = dyn_cast<TypeContextDescriptor>(anyType)) {
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if (!type->isGeneric()) {
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if (auto accessFn = type->getAccessFunction())
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return accessFn(MetadataState::Abstract).Value;
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}
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} else if (auto protocol = dyn_cast<ProtocolDescriptor>(anyType)) {
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return _getSimpleProtocolTypeMetadata(protocol);
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}
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}
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return nullptr;
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}
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}
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swift_unreachable("Unhandled TypeReferenceKind in switch.");
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}
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template<>
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const WitnessTable *
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ProtocolConformanceDescriptor::getWitnessTable(const Metadata *type) const {
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// If needed, check the conditional requirements.
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llvm::SmallVector<const void *, 8> conditionalArgs;
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if (hasConditionalRequirements()) {
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SubstGenericParametersFromMetadata substitutions(type);
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auto error = _checkGenericRequirements(
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getConditionalRequirements(), conditionalArgs,
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[&substitutions](unsigned depth, unsigned index) {
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return substitutions.getMetadata(depth, index).Ptr;
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},
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[&substitutions](const Metadata *type, unsigned index) {
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return substitutions.getWitnessTable(type, index);
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});
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if (error)
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return nullptr;
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}
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#if SWIFT_STDLIB_USE_RELATIVE_PROTOCOL_WITNESS_TABLES
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return (const WitnessTable *)
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swift_getWitnessTableRelative(this, type, conditionalArgs.data());
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#else
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return swift_getWitnessTable(this, type, conditionalArgs.data());
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#endif
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}
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namespace {
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struct ConformanceSection {
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const ProtocolConformanceRecord *Begin, *End;
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ConformanceSection(const ProtocolConformanceRecord *begin,
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const ProtocolConformanceRecord *end)
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: Begin(begin), End(end) {}
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ConformanceSection(const void *ptr, uintptr_t size) {
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auto bytes = reinterpret_cast<const char *>(ptr);
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Begin = reinterpret_cast<const ProtocolConformanceRecord *>(ptr);
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End = reinterpret_cast<const ProtocolConformanceRecord *>(bytes + size);
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}
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const ProtocolConformanceRecord *begin() const {
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return Begin;
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}
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const ProtocolConformanceRecord *end() const {
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return End;
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}
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};
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struct ConformanceCacheKey {
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const Metadata *Type;
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const ProtocolDescriptor *Proto;
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ConformanceCacheKey(const Metadata *type, const ProtocolDescriptor *proto)
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: Type(type), Proto(proto) {
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assert(type);
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}
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friend llvm::hash_code hash_value(const ConformanceCacheKey &key) {
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return llvm::hash_combine(key.Type, key.Proto);
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}
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};
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struct ConformanceCacheEntry {
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private:
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ConformanceCacheKey Key;
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const WitnessTable *Witness;
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public:
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ConformanceCacheEntry(ConformanceCacheKey key, const WitnessTable *witness)
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: Key(key), Witness(witness) {}
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bool matchesKey(const ConformanceCacheKey &key) const {
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return Key.Type == key.Type && Key.Proto == key.Proto;
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}
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friend llvm::hash_code hash_value(const ConformanceCacheEntry &entry) {
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return hash_value(entry.Key);
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}
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template <class... Args>
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static size_t getExtraAllocationSize(Args &&... ignored) {
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return 0;
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}
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/// Get the cached witness table, or null if we cached failure.
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const WitnessTable *getWitnessTable() const {
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return Witness;
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}
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};
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} // end anonymous namespace
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// Conformance Cache.
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struct ConformanceState {
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ConcurrentReadableHashMap<ConformanceCacheEntry> Cache;
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ConcurrentReadableArray<ConformanceSection> SectionsToScan;
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bool scanSectionsBackwards;
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#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
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uintptr_t dyldSharedCacheStart;
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uintptr_t dyldSharedCacheEnd;
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bool hasOverriddenImage;
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bool validateDyldResults;
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// Only populated when validateDyldResults is enabled.
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ConcurrentReadableArray<ConformanceSection> DyldOptimizedSections;
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bool inSharedCache(const void *ptr) {
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auto uintPtr = reinterpret_cast<uintptr_t>(ptr);
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return dyldSharedCacheStart <= uintPtr && uintPtr < dyldSharedCacheEnd;
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}
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bool dyldOptimizationsActive() { return dyldSharedCacheStart != 0; }
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#else
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bool dyldOptimizationsActive() { return false; }
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#endif
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ConformanceState() {
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scanSectionsBackwards =
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runtime::bincompat::useLegacyProtocolConformanceReverseIteration();
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#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
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if (__builtin_available(macOS 12.0, iOS 15.0, tvOS 15.0, watchOS 8.0, *)) {
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if (runtime::environment::SWIFT_DEBUG_ENABLE_SHARED_CACHE_PROTOCOL_CONFORMANCES()) {
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if (&_dyld_swift_optimizations_version) {
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if (_dyld_swift_optimizations_version() ==
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DYLD_EXPECTED_SWIFT_OPTIMIZATIONS_VERSION) {
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size_t length;
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dyldSharedCacheStart =
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(uintptr_t)_dyld_get_shared_cache_range(&length);
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dyldSharedCacheEnd =
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dyldSharedCacheStart ? dyldSharedCacheStart + length : 0;
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validateDyldResults = runtime::environment::
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SWIFT_DEBUG_VALIDATE_SHARED_CACHE_PROTOCOL_CONFORMANCES();
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DYLD_CONFORMANCES_LOG("Shared cache range is %#lx-%#lx",
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dyldSharedCacheStart, dyldSharedCacheEnd);
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} else {
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DYLD_CONFORMANCES_LOG("Disabling dyld protocol conformance "
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"optimizations due to unknown "
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"optimizations version %u",
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_dyld_swift_optimizations_version());
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dyldSharedCacheStart = 0;
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dyldSharedCacheEnd = 0;
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}
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}
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}
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}
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#endif
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// This must run last, as it triggers callbacks that require
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// ConformanceState to be set up.
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initializeProtocolConformanceLookup();
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}
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void cacheResult(const Metadata *type, const ProtocolDescriptor *proto,
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const WitnessTable *witness, size_t sectionsCount) {
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Cache.getOrInsert(ConformanceCacheKey(type, proto),
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[&](ConformanceCacheEntry *entry, bool created) {
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// Create the entry if needed. If it already exists,
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// we're done.
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if (!created)
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return false;
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// Check the current sections count against what was
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// passed in. If a section count was passed in and they
|
|
// don't match, then this is not an authoritative entry
|
|
// and it may have been obsoleted, because the new
|
|
// sections could contain a conformance in a more
|
|
// specific type.
|
|
//
|
|
// If they DO match, then we can safely add. Another
|
|
// thread might be adding new sections at this point,
|
|
// but we will not race with them. That other thread
|
|
// will add the new sections, then clear the cache. When
|
|
// it clears the cache, it will block waiting for this
|
|
// code to complete and relinquish Cache's writer lock.
|
|
// If we cache a stale entry, it will be immediately
|
|
// cleared.
|
|
if (sectionsCount > 0 &&
|
|
SectionsToScan.snapshot().count() != sectionsCount)
|
|
return false; // abandon the new entry
|
|
|
|
::new (entry) ConformanceCacheEntry(
|
|
ConformanceCacheKey(type, proto), witness);
|
|
return true; // keep the new entry
|
|
});
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
void verify() const SWIFT_USED;
|
|
#endif
|
|
};
|
|
|
|
#ifndef NDEBUG
|
|
void ConformanceState::verify() const {
|
|
// Iterate over all of the sections and verify all of the protocol
|
|
// descriptors.
|
|
auto &Self = const_cast<ConformanceState &>(*this);
|
|
for (const auto &Section : Self.SectionsToScan.snapshot()) {
|
|
for (const auto &Record : Section) {
|
|
Record.get()->verify();
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
static Lazy<ConformanceState> Conformances;
|
|
|
|
const void * const swift::_swift_debug_protocolConformanceStatePointer =
|
|
&Conformances;
|
|
|
|
static void _registerProtocolConformances(ConformanceState &C,
|
|
ConformanceSection section) {
|
|
C.SectionsToScan.push_back(section);
|
|
|
|
// Blow away the conformances cache to get rid of any negative entries that
|
|
// may now be obsolete.
|
|
C.Cache.clear();
|
|
}
|
|
|
|
void swift::addImageProtocolConformanceBlockCallbackUnsafe(
|
|
const void *baseAddress,
|
|
const void *conformances, uintptr_t conformancesSize) {
|
|
assert(conformancesSize % sizeof(ProtocolConformanceRecord) == 0 &&
|
|
"conformances section not a multiple of ProtocolConformanceRecord");
|
|
|
|
// Conformance cache should always be sufficiently initialized by this point.
|
|
auto &C = Conformances.unsafeGetAlreadyInitialized();
|
|
|
|
#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
|
|
// If any image in the shared cache is overridden, we need to scan all
|
|
// conformance sections in the shared cache. The pre-built table does NOT work
|
|
// if the protocol, type, or descriptor are in overridden images. Example:
|
|
//
|
|
// libX.dylib: struct S {}
|
|
// libY.dylib: protocol P {}
|
|
// libZ.dylib: extension S: P {}
|
|
//
|
|
// If libX or libY are overridden, then dyld will not return the S: P
|
|
// conformance from libZ. But that conformance still exists and we must still
|
|
// return it! Therefore we must scan libZ (and all other dylibs) even though
|
|
// it is not overridden.
|
|
if (!dyld_shared_cache_some_image_overridden()) {
|
|
// Sections in the shared cache are ignored in favor of the shared cache's
|
|
// pre-built tables.
|
|
if (C.inSharedCache(conformances)) {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"Skipping conformances section %p in the shared cache", conformances);
|
|
if (C.validateDyldResults)
|
|
C.DyldOptimizedSections.push_back(
|
|
ConformanceSection{conformances, conformancesSize});
|
|
return;
|
|
#if DYLD_FIND_PROTOCOL_ON_DISK_CONFORMANCE_DEFINED
|
|
} else if (&_dyld_has_preoptimized_swift_protocol_conformances &&
|
|
_dyld_has_preoptimized_swift_protocol_conformances(
|
|
reinterpret_cast<const mach_header *>(baseAddress))) {
|
|
// dyld may optimize images outside the shared cache. Skip those too.
|
|
DYLD_CONFORMANCES_LOG(
|
|
"Skipping conformances section %p optimized by dyld", conformances);
|
|
if (C.validateDyldResults)
|
|
C.DyldOptimizedSections.push_back(
|
|
ConformanceSection{conformances, conformancesSize});
|
|
return;
|
|
#endif
|
|
} else {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"Adding conformances section %p outside the shared cache",
|
|
conformances);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
// If we have a section, enqueue the conformances for lookup.
|
|
_registerProtocolConformances(
|
|
C, ConformanceSection{conformances, conformancesSize});
|
|
}
|
|
|
|
void swift::addImageProtocolConformanceBlockCallback(
|
|
const void *baseAddress,
|
|
const void *conformances, uintptr_t conformancesSize) {
|
|
Conformances.get();
|
|
addImageProtocolConformanceBlockCallbackUnsafe(baseAddress,
|
|
conformances,
|
|
conformancesSize);
|
|
}
|
|
|
|
void
|
|
swift::swift_registerProtocolConformances(const ProtocolConformanceRecord *begin,
|
|
const ProtocolConformanceRecord *end){
|
|
auto &C = Conformances.get();
|
|
_registerProtocolConformances(C, ConformanceSection{begin, end});
|
|
}
|
|
|
|
/// Search for a conformance descriptor in the ConformanceCache.
|
|
/// First element of the return value is `true` if the result is authoritative
|
|
/// i.e. the result is for the type itself and not a superclass. If `false`
|
|
/// then we cached a conformance on a superclass, but that may be overridden.
|
|
/// A return value of `{ false, nullptr }` indicates nothing was cached.
|
|
static std::pair<bool, const WitnessTable *>
|
|
searchInConformanceCache(const Metadata *type,
|
|
const ProtocolDescriptor *protocol,
|
|
bool instantiateSuperclassMetadata) {
|
|
auto &C = Conformances.get();
|
|
auto origType = type;
|
|
auto snapshot = C.Cache.snapshot();
|
|
|
|
MaybeIncompleteSuperclassIterator superclassIterator{
|
|
type, instantiateSuperclassMetadata};
|
|
for (; auto type = superclassIterator.metadata; ++superclassIterator) {
|
|
if (auto *Value = snapshot.find(ConformanceCacheKey(type, protocol))) {
|
|
return {type == origType, Value->getWitnessTable()};
|
|
}
|
|
}
|
|
|
|
// We did not find a cache entry.
|
|
return {false, nullptr};
|
|
}
|
|
|
|
/// Get the appropriate context descriptor for a type. If the descriptor is a
|
|
/// foreign type descriptor, also return its identity string.
|
|
static std::pair<const ContextDescriptor *, llvm::StringRef>
|
|
getContextDescriptor(const Metadata *conformingType) {
|
|
const auto *description = conformingType->getTypeContextDescriptor();
|
|
if (description) {
|
|
if (description->hasForeignMetadataInitialization()) {
|
|
auto identity = ParsedTypeIdentity::parse(description).FullIdentity;
|
|
return {description, identity};
|
|
}
|
|
return {description, {}};
|
|
}
|
|
|
|
// Handle single-protocol existential types for self-conformance.
|
|
auto *existentialType = dyn_cast<ExistentialTypeMetadata>(conformingType);
|
|
if (existentialType == nullptr ||
|
|
existentialType->getProtocols().size() != 1 ||
|
|
existentialType->getSuperclassConstraint() != nullptr)
|
|
return {nullptr, {}};
|
|
|
|
auto proto = existentialType->getProtocols()[0];
|
|
|
|
#if SWIFT_OBJC_INTEROP
|
|
if (proto.isObjC())
|
|
return {nullptr, {}};
|
|
#endif
|
|
|
|
return {proto.getSwiftProtocol(), {}};
|
|
}
|
|
|
|
namespace {
|
|
/// Describes a protocol conformance "candidate" that can be checked
|
|
/// against a type metadata.
|
|
class ConformanceCandidate {
|
|
const void *candidate;
|
|
bool candidateIsMetadata;
|
|
|
|
public:
|
|
ConformanceCandidate() : candidate(0), candidateIsMetadata(false) { }
|
|
|
|
ConformanceCandidate(const ProtocolConformanceDescriptor &conformance)
|
|
: ConformanceCandidate()
|
|
{
|
|
if (auto description = conformance.getTypeDescriptor()) {
|
|
candidate = description;
|
|
candidateIsMetadata = false;
|
|
return;
|
|
}
|
|
|
|
if (auto metadata = conformance.getCanonicalTypeMetadata()) {
|
|
candidate = metadata;
|
|
candidateIsMetadata = true;
|
|
return;
|
|
}
|
|
}
|
|
|
|
/// Whether the conforming type exactly matches the conformance candidate.
|
|
bool matches(const Metadata *conformingType) const {
|
|
// Check whether the types match.
|
|
if (candidateIsMetadata && conformingType == candidate)
|
|
return true;
|
|
|
|
// Check whether the nominal type descriptors match.
|
|
if (!candidateIsMetadata) {
|
|
const auto *description = std::get<const ContextDescriptor *>(
|
|
getContextDescriptor(conformingType));
|
|
auto candidateDescription =
|
|
static_cast<const ContextDescriptor *>(candidate);
|
|
if (description && equalContexts(description, candidateDescription))
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/// Retrieve the type that matches the conformance candidate, which may
|
|
/// be a superclass of the given type. Returns null if this type does not
|
|
/// match this conformance, along with the final metadata state of the
|
|
/// superclass iterator.
|
|
std::pair<const Metadata *, llvm::Optional<MetadataState>>
|
|
getMatchingType(const Metadata *conformingType,
|
|
bool instantiateSuperclassMetadata) const {
|
|
MaybeIncompleteSuperclassIterator superclassIterator{
|
|
conformingType, instantiateSuperclassMetadata};
|
|
for (; auto conformingType = superclassIterator.metadata;
|
|
++superclassIterator) {
|
|
if (matches(conformingType))
|
|
return {conformingType, llvm::None};
|
|
}
|
|
|
|
return {nullptr, superclassIterator.state};
|
|
}
|
|
};
|
|
}
|
|
|
|
static void validateDyldResults(
|
|
ConformanceState &C, const Metadata *type,
|
|
const ProtocolDescriptor *protocol,
|
|
const WitnessTable *dyldCachedWitnessTable,
|
|
const ProtocolConformanceDescriptor *dyldCachedConformanceDescriptor,
|
|
bool instantiateSuperclassMetadata) {
|
|
#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
|
|
if (!C.dyldOptimizationsActive() || !C.validateDyldResults)
|
|
return;
|
|
|
|
llvm::SmallVector<const ProtocolConformanceDescriptor *, 8> conformances;
|
|
for (auto §ion : C.DyldOptimizedSections.snapshot()) {
|
|
for (const auto &record : section) {
|
|
auto &descriptor = *record.get();
|
|
if (descriptor.getProtocol() != protocol)
|
|
continue;
|
|
|
|
ConformanceCandidate candidate(descriptor);
|
|
if (std::get<const Metadata *>(
|
|
candidate.getMatchingType(type, instantiateSuperclassMetadata)))
|
|
conformances.push_back(&descriptor);
|
|
}
|
|
}
|
|
|
|
auto conformancesString = [&]() -> std::string {
|
|
std::string result = "";
|
|
for (auto *conformance : conformances) {
|
|
if (!result.empty())
|
|
result += ", ";
|
|
result += "0x";
|
|
result += llvm::utohexstr(reinterpret_cast<uint64_t>(conformance));
|
|
}
|
|
return result;
|
|
};
|
|
|
|
if (dyldCachedConformanceDescriptor) {
|
|
if (std::find(conformances.begin(), conformances.end(),
|
|
dyldCachedConformanceDescriptor) == conformances.end()) {
|
|
auto typeName = swift_getTypeName(type, true);
|
|
swift::fatalError(
|
|
0,
|
|
"Checking conformance of %.*s %p to %s %p - dyld cached conformance "
|
|
"descriptor %p not found in conformance records: (%s)\n",
|
|
(int)typeName.length, typeName.data, type, protocol->Name.get(),
|
|
protocol, dyldCachedConformanceDescriptor,
|
|
conformancesString().c_str());
|
|
}
|
|
} else {
|
|
if (!conformances.empty()) {
|
|
auto typeName = swift_getTypeName(type, true);
|
|
swift::fatalError(
|
|
0,
|
|
"Checking conformance of %.*s %p to %s %p - dyld found no "
|
|
"conformance descriptor, but matching descriptors exist: (%s)\n",
|
|
(int)typeName.length, typeName.data, type, protocol->Name.get(),
|
|
protocol, conformancesString().c_str());
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
|
|
static _dyld_protocol_conformance_result getDyldSharedCacheConformance(
|
|
ConformanceState &C, const ProtocolDescriptor *protocol,
|
|
const ClassMetadata *objcClassMetadata,
|
|
const ContextDescriptor *description, llvm::StringRef foreignTypeIdentity) {
|
|
// Protocols that aren't in the shared cache will never be found in the shared
|
|
// cache conformances, skip the call.
|
|
if (!C.inSharedCache(protocol)) {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"Skipping shared cache lookup, protocol %p is not in shared cache.",
|
|
protocol);
|
|
return {_dyld_protocol_conformance_result_kind_not_found, nullptr};
|
|
}
|
|
|
|
if (!foreignTypeIdentity.empty()) {
|
|
// Foreign types are non-unique so those can still be found in the shared
|
|
// cache even if the identity string is outside.
|
|
DYLD_CONFORMANCES_LOG(
|
|
"_dyld_find_foreign_type_protocol_conformance(%p, %.*s, %zu)", protocol,
|
|
(int)foreignTypeIdentity.size(), foreignTypeIdentity.data(),
|
|
foreignTypeIdentity.size());
|
|
return _dyld_find_foreign_type_protocol_conformance(
|
|
protocol, foreignTypeIdentity.data(), foreignTypeIdentity.size());
|
|
} else {
|
|
// If both the ObjC class metadata and description are outside the shared
|
|
// cache, then we'll never find a shared cache conformance, skip the call.
|
|
// We can still find a shared cache conformance if one is inside and one is
|
|
// outside.
|
|
if (!C.inSharedCache(objcClassMetadata) && !C.inSharedCache(description)) {
|
|
DYLD_CONFORMANCES_LOG("Skipping shared cache lookup, class %p and "
|
|
"description %p are not in shared cache.",
|
|
objcClassMetadata, description);
|
|
return {_dyld_protocol_conformance_result_kind_not_found, nullptr};
|
|
}
|
|
|
|
DYLD_CONFORMANCES_LOG("_dyld_find_protocol_conformance(%p, %p, %p)",
|
|
protocol, objcClassMetadata, description);
|
|
return _dyld_find_protocol_conformance(protocol, objcClassMetadata,
|
|
description);
|
|
}
|
|
}
|
|
|
|
static _dyld_protocol_conformance_result getDyldOnDiskConformance(
|
|
ConformanceState &C, const ProtocolDescriptor *protocol,
|
|
const ClassMetadata *objcClassMetadata,
|
|
const ContextDescriptor *description, llvm::StringRef foreignTypeIdentity) {
|
|
#if DYLD_FIND_PROTOCOL_ON_DISK_CONFORMANCE_DEFINED
|
|
if (&_dyld_find_foreign_type_protocol_conformance_on_disk &&
|
|
&_dyld_find_protocol_conformance_on_disk) {
|
|
if (!foreignTypeIdentity.empty()) {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"_dyld_find_foreign_type_protocol_conformance_on_disk(%"
|
|
"p, %.*s, %zu, 0)",
|
|
protocol, (int)foreignTypeIdentity.size(), foreignTypeIdentity.data(),
|
|
foreignTypeIdentity.size());
|
|
return _dyld_find_foreign_type_protocol_conformance_on_disk(
|
|
protocol, foreignTypeIdentity.data(), foreignTypeIdentity.size(), 0);
|
|
} else {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"_dyld_find_protocol_conformance_on_disk(%p, %p, %p, 0)", protocol,
|
|
objcClassMetadata, description);
|
|
return _dyld_find_protocol_conformance_on_disk(
|
|
protocol, objcClassMetadata, description, 0);
|
|
}
|
|
}
|
|
#endif
|
|
return {_dyld_protocol_conformance_result_kind_not_found, nullptr};
|
|
}
|
|
#endif
|
|
|
|
/// Query dyld for a protocol conformance, if supported. The return
|
|
/// value is a tuple consisting of the found witness table (if any), the found
|
|
/// conformance descriptor (if any), and a bool that's true if a failure is
|
|
/// definitive.
|
|
static std::tuple<const WitnessTable *, const ProtocolConformanceDescriptor *,
|
|
bool>
|
|
findConformanceWithDyld(ConformanceState &C, const Metadata *type,
|
|
const ProtocolDescriptor *protocol,
|
|
bool instantiateSuperclassMetadata) {
|
|
#if USE_DYLD_SHARED_CACHE_CONFORMANCE_TABLES
|
|
const ContextDescriptor *description;
|
|
llvm::StringRef foreignTypeIdentity;
|
|
std::tie(description, foreignTypeIdentity) = getContextDescriptor(type);
|
|
|
|
// dyld expects the ObjC class, if any, as the second parameter.
|
|
auto objcClassMetadata = swift_getObjCClassFromMetadataConditional(type);
|
|
#if SHARED_CACHE_LOG_ENABLED
|
|
auto typeName = swift_getTypeName(type, true);
|
|
DYLD_CONFORMANCES_LOG("Looking up conformance of %.*s (type=%p, "
|
|
"objcClassMetadata=%p, description=%p) to %s (%p)",
|
|
(int)typeName.length, typeName.data, type,
|
|
objcClassMetadata, description, protocol->Name.get(),
|
|
protocol);
|
|
#endif
|
|
_dyld_protocol_conformance_result dyldResult;
|
|
if (C.scanSectionsBackwards) {
|
|
// Search "on disk" first, then shared cache.
|
|
dyldResult = getDyldOnDiskConformance(C, protocol, objcClassMetadata,
|
|
description, foreignTypeIdentity);
|
|
if (dyldResult.kind == _dyld_protocol_conformance_result_kind_not_found)
|
|
dyldResult = getDyldSharedCacheConformance(
|
|
C, protocol, objcClassMetadata, description, foreignTypeIdentity);
|
|
} else {
|
|
// In normal operation, search the shared cache first.
|
|
dyldResult = getDyldSharedCacheConformance(
|
|
C, protocol, objcClassMetadata, description, foreignTypeIdentity);
|
|
if (dyldResult.kind == _dyld_protocol_conformance_result_kind_not_found)
|
|
dyldResult = getDyldOnDiskConformance(C, protocol, objcClassMetadata,
|
|
description, foreignTypeIdentity);
|
|
}
|
|
|
|
switch (dyldResult.kind) {
|
|
case _dyld_protocol_conformance_result_kind_found_descriptor: {
|
|
auto *conformanceDescriptor =
|
|
reinterpret_cast<const ProtocolConformanceDescriptor *>(
|
|
dyldResult.value);
|
|
|
|
assert(conformanceDescriptor->getProtocol() == protocol);
|
|
assert(std::get<const Metadata *>(
|
|
ConformanceCandidate{*conformanceDescriptor}.getMatchingType(
|
|
type, instantiateSuperclassMetadata)));
|
|
|
|
if (conformanceDescriptor->getGenericWitnessTable()) {
|
|
DYLD_CONFORMANCES_LOG(
|
|
"DYLD found generic conformance descriptor %p for %s, continuing",
|
|
conformanceDescriptor, protocol->Name.get());
|
|
return std::make_tuple(nullptr, conformanceDescriptor, false);
|
|
} else {
|
|
// When there are no generics, we can retrieve the witness table cheaply,
|
|
// so do it up front.
|
|
DYLD_CONFORMANCES_LOG("DYLD Found conformance descriptor %p for %s",
|
|
conformanceDescriptor, protocol->Name.get());
|
|
auto *witnessTable = conformanceDescriptor->getWitnessTable(type);
|
|
return std::make_tuple(witnessTable, conformanceDescriptor, false);
|
|
}
|
|
break;
|
|
}
|
|
case _dyld_protocol_conformance_result_kind_found_witness_table:
|
|
// If we found a witness table then we're done.
|
|
DYLD_CONFORMANCES_LOG("DYLD found witness table %p for conformance to %s",
|
|
dyldResult.value, protocol->Name.get());
|
|
return std::make_tuple(reinterpret_cast<const WitnessTable *>(dyldResult.value), nullptr,
|
|
false);
|
|
case _dyld_protocol_conformance_result_kind_not_found:
|
|
// If nothing is found, then we'll proceed with checking the runtime's
|
|
// caches and scanning conformance records.
|
|
DYLD_CONFORMANCES_LOG("DYLD did not find conformance to %s",
|
|
protocol->Name.get());
|
|
return std::make_tuple(nullptr, nullptr, false);
|
|
break;
|
|
case _dyld_protocol_conformance_result_kind_definitive_failure:
|
|
// This type is known not to conform to this protocol. Return failure
|
|
// without any further checks.
|
|
DYLD_CONFORMANCES_LOG("DYLD found definitive failure for %s",
|
|
protocol->Name.get());
|
|
return std::make_tuple(nullptr, nullptr, true);
|
|
default:
|
|
// Other values may be added. Consider them equivalent to not_found until
|
|
// we implement code to handle them.
|
|
DYLD_CONFORMANCES_LOG(
|
|
"Unknown result kind %lu from _dyld_find_protocol_conformance()",
|
|
(unsigned long)dyldResult.kind);
|
|
return std::make_tuple(nullptr, nullptr, false);
|
|
}
|
|
#else
|
|
return std::make_tuple(nullptr, nullptr, false);
|
|
#endif
|
|
}
|
|
|
|
/// Check if a type conforms to a protocol, possibly instantiating superclasses
|
|
/// that have not yet been instantiated. The return value is a pair consisting
|
|
/// of the witness table for the conformance (or NULL if no conformance was
|
|
/// found), and a boolean indicating whether there are uninstantiated
|
|
/// superclasses that were not searched.
|
|
static std::pair<const WitnessTable *, bool>
|
|
swift_conformsToProtocolMaybeInstantiateSuperclasses(
|
|
const Metadata *const type, const ProtocolDescriptor *protocol,
|
|
bool instantiateSuperclassMetadata) {
|
|
auto &C = Conformances.get();
|
|
|
|
const WitnessTable *dyldCachedWitnessTable = nullptr;
|
|
const ProtocolConformanceDescriptor *dyldCachedConformanceDescriptor =
|
|
nullptr;
|
|
|
|
// Track whether we have uninstantiated superclasses. Each time we iterate
|
|
// over our superclasses, we check the final state to see if there are more
|
|
// superclasses we haven't instantiated by calling noteFinalMetadataState.
|
|
// If we ever see Abstract, that means there are more superclasses we can't
|
|
// check yet, and we might get a false negative. We have to do this after each
|
|
// iteration (really, just the first iteration, but it's hard to keep track of
|
|
// which iteration is the first time), because another thread might
|
|
// instantiate the superclass while we're in the middle of searching. If we
|
|
// only look at the state after the last iteration, we might have hit a false
|
|
// negative before that no longer shows up.
|
|
bool hasUninstantiatedSuperclass = false;
|
|
auto noteFinalMetadataState = [&](llvm::Optional<MetadataState> state) {
|
|
hasUninstantiatedSuperclass =
|
|
hasUninstantiatedSuperclass || state == MetadataState::Abstract;
|
|
};
|
|
|
|
// Search the shared cache tables for a conformance for this type, and for
|
|
// superclasses (if it's a class).
|
|
if (C.dyldOptimizationsActive()) {
|
|
MaybeIncompleteSuperclassIterator superclassIterator{
|
|
type, instantiateSuperclassMetadata};
|
|
for (; auto dyldSearchType = superclassIterator.metadata;
|
|
++superclassIterator) {
|
|
bool definitiveFailure;
|
|
std::tie(dyldCachedWitnessTable, dyldCachedConformanceDescriptor,
|
|
definitiveFailure) =
|
|
findConformanceWithDyld(C, dyldSearchType, protocol,
|
|
instantiateSuperclassMetadata);
|
|
|
|
if (definitiveFailure)
|
|
return {nullptr, false};
|
|
|
|
if (dyldCachedWitnessTable || dyldCachedConformanceDescriptor)
|
|
break;
|
|
}
|
|
noteFinalMetadataState(superclassIterator.state);
|
|
|
|
validateDyldResults(C, type, protocol, dyldCachedWitnessTable,
|
|
dyldCachedConformanceDescriptor,
|
|
instantiateSuperclassMetadata);
|
|
// Return a cached result if we got a witness table. We can't do this if
|
|
// scanSectionsBackwards is set, since a scanned conformance can override a
|
|
// cached result in that case.
|
|
if (!C.scanSectionsBackwards)
|
|
if (dyldCachedWitnessTable)
|
|
return {dyldCachedWitnessTable, false};
|
|
}
|
|
|
|
// See if we have an authoritative cached conformance. The
|
|
// ConcurrentReadableHashMap data structure allows us to search the map
|
|
// concurrently without locking.
|
|
auto found =
|
|
searchInConformanceCache(type, protocol, instantiateSuperclassMetadata);
|
|
if (found.first) {
|
|
// An authoritative negative result can be overridden by a result from dyld.
|
|
if (!found.second) {
|
|
if (dyldCachedWitnessTable)
|
|
return {dyldCachedWitnessTable, false};
|
|
}
|
|
return {found.second, false};
|
|
}
|
|
|
|
if (dyldCachedConformanceDescriptor) {
|
|
ConformanceCandidate candidate(*dyldCachedConformanceDescriptor);
|
|
auto *matchingType = std::get<const Metadata *>(
|
|
candidate.getMatchingType(type, instantiateSuperclassMetadata));
|
|
assert(matchingType);
|
|
auto witness = dyldCachedConformanceDescriptor->getWitnessTable(matchingType);
|
|
C.cacheResult(type, protocol, witness, /*always cache*/ 0);
|
|
DYLD_CONFORMANCES_LOG("Caching generic conformance to %s found by DYLD",
|
|
protocol->Name.get());
|
|
return {witness, false};
|
|
}
|
|
|
|
// Scan conformance records.
|
|
llvm::SmallDenseMap<const Metadata *, const WitnessTable *> foundWitnesses;
|
|
auto processSection = [&](const ConformanceSection §ion) {
|
|
// Eagerly pull records for nondependent witnesses into our cache.
|
|
auto processDescriptor = [&](const ProtocolConformanceDescriptor &descriptor) {
|
|
// We only care about conformances for this protocol.
|
|
if (descriptor.getProtocol() != protocol)
|
|
return;
|
|
|
|
// If there's a matching type, record the positive result and return it.
|
|
// The matching type is exact, so they can't go stale, and we should
|
|
// always cache them.
|
|
ConformanceCandidate candidate(descriptor);
|
|
const Metadata *matchingType;
|
|
llvm::Optional<MetadataState> finalState;
|
|
std::tie(matchingType, finalState) =
|
|
candidate.getMatchingType(type, instantiateSuperclassMetadata);
|
|
noteFinalMetadataState(finalState);
|
|
if (matchingType) {
|
|
auto witness = descriptor.getWitnessTable(matchingType);
|
|
C.cacheResult(matchingType, protocol, witness, /*always cache*/ 0);
|
|
foundWitnesses.insert({matchingType, witness});
|
|
}
|
|
};
|
|
|
|
if (C.scanSectionsBackwards) {
|
|
for (const auto &record : llvm::reverse(section))
|
|
processDescriptor(*record.get());
|
|
} else {
|
|
for (const auto &record : section)
|
|
processDescriptor(*record.get());
|
|
}
|
|
};
|
|
|
|
auto traceState =
|
|
runtime::trace::protocol_conformance_scan_begin(type, protocol);
|
|
|
|
auto snapshot = C.SectionsToScan.snapshot();
|
|
if (C.scanSectionsBackwards) {
|
|
for (auto §ion : llvm::reverse(snapshot))
|
|
processSection(section);
|
|
} else {
|
|
for (auto §ion : snapshot)
|
|
processSection(section);
|
|
}
|
|
|
|
// Find the most specific conformance that was scanned.
|
|
const WitnessTable *foundWitness = nullptr;
|
|
const Metadata *foundType = nullptr;
|
|
|
|
MaybeIncompleteSuperclassIterator superclassIterator{
|
|
type, instantiateSuperclassMetadata};
|
|
for (; auto searchType = superclassIterator.metadata; ++superclassIterator) {
|
|
const WitnessTable *witness = foundWitnesses.lookup(searchType);
|
|
if (witness) {
|
|
if (!foundType) {
|
|
foundWitness = witness;
|
|
foundType = searchType;
|
|
} else {
|
|
auto foundName = swift_getTypeName(foundType, true);
|
|
auto searchName = swift_getTypeName(searchType, true);
|
|
swift::warning(RuntimeErrorFlagNone,
|
|
"Warning: '%.*s' conforms to protocol '%s', but it also "
|
|
"inherits conformance from '%.*s'. Relying on a "
|
|
"particular conformance is undefined behaviour.\n",
|
|
(int)foundName.length, foundName.data,
|
|
protocol->Name.get(),
|
|
(int)searchName.length, searchName.data);
|
|
}
|
|
}
|
|
}
|
|
noteFinalMetadataState(superclassIterator.state);
|
|
|
|
traceState.end(foundWitness);
|
|
|
|
// If it's for a superclass or if we didn't find anything, then add an
|
|
// authoritative entry for this type.
|
|
if (foundType != type)
|
|
// Do not cache negative results if there were uninstantiated superclasses
|
|
// we didn't search. They might have a conformance that will be found later.
|
|
if (foundWitness || !hasUninstantiatedSuperclass)
|
|
C.cacheResult(type, protocol, foundWitness, snapshot.count());
|
|
|
|
// A negative result can be overridden by a result from dyld.
|
|
if (!foundWitness) {
|
|
if (dyldCachedWitnessTable)
|
|
return {dyldCachedWitnessTable, false};
|
|
}
|
|
return {foundWitness, hasUninstantiatedSuperclass};
|
|
}
|
|
|
|
static const WitnessTable *
|
|
swift_conformsToProtocolCommonImpl(const Metadata *const type,
|
|
const ProtocolDescriptor *protocol) {
|
|
const WitnessTable *table;
|
|
bool hasUninstantiatedSuperclass;
|
|
|
|
// First, try without instantiating any new superclasses. This avoids
|
|
// an infinite loop for cases like `class Sub: Super<Sub>`. In cases like
|
|
// that, the conformance must exist on the subclass (or at least somewhere
|
|
// in the chain before we get to an uninstantiated superclass) so this search
|
|
// will succeed without trying to instantiate Super while it's already being
|
|
// instantiated.=
|
|
std::tie(table, hasUninstantiatedSuperclass) =
|
|
swift_conformsToProtocolMaybeInstantiateSuperclasses(
|
|
type, protocol, false /*instantiateSuperclassMetadata*/);
|
|
|
|
// If no conformance was found, and there is an uninstantiated superclass that
|
|
// was not searched, then try the search again and instantiate all
|
|
// superclasses.
|
|
if (!table && hasUninstantiatedSuperclass)
|
|
std::tie(table, hasUninstantiatedSuperclass) =
|
|
swift_conformsToProtocolMaybeInstantiateSuperclasses(
|
|
type, protocol, true /*instantiateSuperclassMetadata*/);
|
|
|
|
return table;
|
|
}
|
|
|
|
static const WitnessTable *
|
|
swift_conformsToProtocol2Impl(const Metadata *const type,
|
|
const ProtocolDescriptor *protocol) {
|
|
protocol = swift_auth_data_non_address(
|
|
protocol, SpecialPointerAuthDiscriminators::ProtocolDescriptor);
|
|
return swift_conformsToProtocolCommonImpl(type, protocol);
|
|
}
|
|
|
|
static const WitnessTable *
|
|
swift_conformsToProtocolImpl(const Metadata *const type,
|
|
const void *protocol) {
|
|
// This call takes `protocol` without a ptrauth signature. We declare
|
|
// it as `void *` to avoid the implicit ptrauth we get from the
|
|
// ptrauth_struct attribute. The static_cast implicitly signs the
|
|
// pointer when we call through to the implementation in
|
|
// swift_conformsToProtocolCommon.
|
|
return swift_conformsToProtocolCommonImpl(
|
|
type, static_cast<const ProtocolDescriptor *>(protocol));
|
|
}
|
|
|
|
const ContextDescriptor *
|
|
swift::_searchConformancesByMangledTypeName(Demangle::NodePointer node) {
|
|
auto traceState = runtime::trace::protocol_conformance_scan_begin(node);
|
|
|
|
auto &C = Conformances.get();
|
|
|
|
for (auto §ion : C.SectionsToScan.snapshot()) {
|
|
for (const auto &record : section) {
|
|
if (auto ntd = record->getTypeDescriptor()) {
|
|
if (_contextDescriptorMatchesMangling(ntd, node))
|
|
return traceState.end(ntd);
|
|
}
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
template <typename HandleObjc>
|
|
bool isSwiftClassMetadataSubclass(const ClassMetadata *subclass,
|
|
const ClassMetadata *superclass,
|
|
HandleObjc handleObjc) {
|
|
assert(subclass);
|
|
assert(superclass);
|
|
|
|
llvm::Optional<MetadataState> subclassState = llvm::None;
|
|
while (true) {
|
|
auto response = getSuperclassForMaybeIncompleteMetadata(
|
|
subclass, subclassState, true /*instantiateSuperclassMetadata*/);
|
|
if (response.Value == superclass)
|
|
return true;
|
|
if (!response.Value)
|
|
return false;
|
|
|
|
subclass = dyn_cast<ClassMetadata>(response.Value);
|
|
if (!subclass || subclass->isPureObjC())
|
|
return handleObjc(response.Value, superclass);
|
|
}
|
|
}
|
|
|
|
// Whether the provided `subclass` is metadata for a subclass* of the superclass
|
|
// whose metadata is specified.
|
|
//
|
|
// The function is robust against incomplete metadata for both subclass and
|
|
// superclass. In the worst case, each intervening class between subclass and
|
|
// superclass is demangled. Besides that slow path, there are a number of fast
|
|
// paths:
|
|
// - both classes are ObjC: swift_dynamicCastMetatype
|
|
// - Complete subclass metadata: loop over Superclass fields
|
|
// - NonTransitiveComplete: read the Superclass field once
|
|
//
|
|
// * A non-strict subclass; that is, given a class X, isSubclass(X.self, X.self)
|
|
// is true.
|
|
static bool isSubclass(const Metadata *subclass, const Metadata *superclass) {
|
|
assert(subclass);
|
|
assert(superclass);
|
|
assert(subclass->isAnyClass());
|
|
assert(superclass->isAnyClass());
|
|
|
|
if (subclass == superclass)
|
|
return true;
|
|
if (!isa<ClassMetadata>(subclass)) {
|
|
if (!isa<ClassMetadata>(superclass)) {
|
|
// Only ClassMetadata can be incomplete; when the class metadata is not
|
|
// ClassMetadata, just use swift_dynamicCastMetatype.
|
|
return swift_dynamicCastMetatype(subclass, superclass);
|
|
} else {
|
|
// subclass is ObjC, but superclass is not; since it is not possible for
|
|
// any ObjC class to be a subclass of any Swift class, this subclass is
|
|
// not a subclass of this superclass.
|
|
return false;
|
|
}
|
|
}
|
|
const ClassMetadata *swiftSubclass = cast<ClassMetadata>(subclass);
|
|
#if SWIFT_OBJC_INTEROP
|
|
if (auto *objcSuperclass = dyn_cast<ObjCClassWrapperMetadata>(superclass)) {
|
|
// Walk up swiftSubclass's ancestors until we get to an ObjC class, then
|
|
// kick over to swift_dynamicCastMetatype.
|
|
return isSwiftClassMetadataSubclass(
|
|
swiftSubclass, objcSuperclass->Class,
|
|
[](const Metadata *intermediate, const Metadata *superclass) {
|
|
// Intermediate is an ObjC class, and superclass is an ObjC class;
|
|
// as above, just use swift_dynamicCastMetatype.
|
|
return swift_dynamicCastMetatype(intermediate, superclass);
|
|
});
|
|
return false;
|
|
}
|
|
#endif
|
|
if (isa<ForeignClassMetadata>(superclass)) {
|
|
// superclass is foreign, but subclass is not (if it were, the above
|
|
// !isa<ClassMetadata> condition would have been entered). Since it is not
|
|
// possible for any Swift class to be a subclass of any foreign superclass,
|
|
// this subclass is not a subclass of this superclass.
|
|
return false;
|
|
}
|
|
auto swiftSuperclass = cast<ClassMetadata>(superclass);
|
|
return isSwiftClassMetadataSubclass(swiftSubclass, swiftSuperclass,
|
|
[](const Metadata *, const Metadata *) {
|
|
// Because (1) no ObjC classes inherit
|
|
// from Swift classes and (2)
|
|
// `superclass` is not ObjC, if some
|
|
// ancestor of `subclass` is ObjC, then
|
|
// `subclass` cannot descend from
|
|
// `superclass` (otherwise at some point
|
|
// some ObjC class would have to inherit
|
|
// from a Swift class).
|
|
return false;
|
|
});
|
|
}
|
|
|
|
static bool isSubclassOrExistential(const Metadata *subclass,
|
|
const Metadata *superclass) {
|
|
// If the type which is constrained to a base class is an existential
|
|
// type, and if that existential type includes a superclass constraint,
|
|
// just require that the superclass by which the existential is
|
|
// constrained is a subclass of the base class.
|
|
if (auto *existential = dyn_cast<ExistentialTypeMetadata>(subclass)) {
|
|
if (auto *superclassConstraint = existential->getSuperclassConstraint())
|
|
subclass = superclassConstraint;
|
|
}
|
|
|
|
return isSubclass(subclass, superclass);
|
|
}
|
|
|
|
static llvm::Optional<TypeLookupError>
|
|
satisfiesLayoutConstraint(const GenericRequirementDescriptor &req,
|
|
const Metadata *subjectType) {
|
|
switch (req.getLayout()) {
|
|
case GenericRequirementLayoutKind::Class:
|
|
if (!subjectType->satisfiesClassConstraint()) {
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"subject type %.*s does not satisfy class constraint",
|
|
(int)req.getParam().size(), req.getParam().data());
|
|
}
|
|
return llvm::None;
|
|
}
|
|
|
|
// Unknown layout.
|
|
return TYPE_LOOKUP_ERROR_FMT("unknown layout kind %u", req.getLayout());
|
|
}
|
|
|
|
SWIFT_CC(swift)
|
|
SWIFT_RUNTIME_STDLIB_SPI
|
|
bool swift::_swift_class_isSubclass(const Metadata *subclass,
|
|
const Metadata *superclass) {
|
|
return isSubclass(subclass, superclass);
|
|
}
|
|
|
|
static llvm::Optional<TypeLookupError>
|
|
checkGenericRequirement(const GenericRequirementDescriptor &req,
|
|
llvm::SmallVectorImpl<const void *> &extraArguments,
|
|
SubstGenericParameterFn substGenericParam,
|
|
SubstDependentWitnessTableFn substWitnessTable) {
|
|
assert(!req.getFlags().isPackRequirement());
|
|
|
|
// Make sure we understand the requirement we're dealing with.
|
|
if (!req.hasKnownKind())
|
|
return TypeLookupError("unknown kind");
|
|
|
|
// Resolve the subject generic parameter.
|
|
auto result = swift_getTypeByMangledName(
|
|
MetadataState::Abstract, req.getParam(), extraArguments.data(),
|
|
substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
const Metadata *subjectType = result.getType().getMetadata();
|
|
|
|
// Check the requirement.
|
|
switch (req.getKind()) {
|
|
case GenericRequirementKind::Protocol: {
|
|
const WitnessTable *witnessTable = nullptr;
|
|
if (!_conformsToProtocol(nullptr, subjectType, req.getProtocol(),
|
|
&witnessTable)) {
|
|
const char *protoName =
|
|
req.getProtocol() ? req.getProtocol().getName() : "<null>";
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"subject type %.*s does not conform to protocol %s",
|
|
(int)req.getParam().size(), req.getParam().data(), protoName);
|
|
}
|
|
|
|
// If we need a witness table, add it.
|
|
if (req.getProtocol().needsWitnessTable()) {
|
|
assert(witnessTable);
|
|
extraArguments.push_back(witnessTable);
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameType: {
|
|
// Demangle the second type under the given substitutions.
|
|
auto result = swift_getTypeByMangledName(
|
|
MetadataState::Abstract, req.getMangledTypeName(),
|
|
extraArguments.data(), substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
auto otherType = result.getType().getMetadata();
|
|
|
|
// Check that the types are equivalent.
|
|
if (subjectType != otherType) {
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"subject type %.*s does not match %.*s", (int)req.getParam().size(),
|
|
req.getParam().data(), (int)req.getMangledTypeName().size(),
|
|
req.getMangledTypeName().data());
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::Layout: {
|
|
return satisfiesLayoutConstraint(req, subjectType);
|
|
}
|
|
|
|
case GenericRequirementKind::BaseClass: {
|
|
// Demangle the base type under the given substitutions.
|
|
auto result = swift_getTypeByMangledName(
|
|
MetadataState::Abstract, req.getMangledTypeName(),
|
|
extraArguments.data(), substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
auto baseType = result.getType().getMetadata();
|
|
|
|
if (!isSubclassOrExistential(subjectType, baseType))
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"%.*s is not subclass of %.*s", (int)req.getParam().size(),
|
|
req.getParam().data(), (int)req.getMangledTypeName().size(),
|
|
req.getMangledTypeName().data());
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameConformance: {
|
|
// FIXME: Implement this check.
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameShape: {
|
|
return TYPE_LOOKUP_ERROR_FMT("can't have same-shape requirement where "
|
|
"subject type is not a pack");
|
|
}
|
|
}
|
|
|
|
// Unknown generic requirement kind.
|
|
return TYPE_LOOKUP_ERROR_FMT("unknown generic requirement kind %u",
|
|
(unsigned)req.getKind());
|
|
}
|
|
|
|
static llvm::Optional<TypeLookupError>
|
|
checkGenericPackRequirement(const GenericRequirementDescriptor &req,
|
|
llvm::SmallVectorImpl<const void *> &extraArguments,
|
|
SubstGenericParameterFn substGenericParam,
|
|
SubstDependentWitnessTableFn substWitnessTable) {
|
|
assert(req.getFlags().isPackRequirement());
|
|
|
|
// Make sure we understand the requirement we're dealing with.
|
|
if (!req.hasKnownKind())
|
|
return TypeLookupError("unknown kind");
|
|
|
|
// Resolve the subject generic parameter.
|
|
auto result = swift::getTypePackByMangledName(
|
|
req.getParam(), extraArguments.data(),
|
|
substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
MetadataPackPointer subjectType = result.getType();
|
|
assert(subjectType.getLifetime() == PackLifetime::OnHeap);
|
|
|
|
// Check the requirement.
|
|
switch (req.getKind()) {
|
|
case GenericRequirementKind::Protocol: {
|
|
llvm::SmallVector<const WitnessTable *, 4> witnessTables;
|
|
|
|
// Look up the conformance of each pack element to the protocol.
|
|
for (size_t i = 0, e = subjectType.getNumElements(); i < e; ++i) {
|
|
const Metadata *elt = subjectType.getElements()[i];
|
|
|
|
const WitnessTable *witnessTable = nullptr;
|
|
if (!_conformsToProtocol(nullptr, elt, req.getProtocol(),
|
|
&witnessTable)) {
|
|
const char *protoName =
|
|
req.getProtocol() ? req.getProtocol().getName() : "<null>";
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"subject type %.*s does not conform to protocol %s at pack index %lu",
|
|
(int)req.getParam().size(), req.getParam().data(), protoName, i);
|
|
}
|
|
|
|
if (req.getProtocol().needsWitnessTable())
|
|
witnessTables.push_back(witnessTable);
|
|
}
|
|
|
|
// If we need a witness table, add it.
|
|
if (req.getProtocol().needsWitnessTable()) {
|
|
assert(witnessTables.size() == subjectType.getNumElements());
|
|
auto *pack = swift_allocateWitnessTablePack(witnessTables.data(),
|
|
witnessTables.size());
|
|
extraArguments.push_back(pack);
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameType: {
|
|
// Resolve the constraint generic parameter.
|
|
auto result = swift::getTypePackByMangledName(
|
|
req.getMangledTypeName(), extraArguments.data(),
|
|
substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
MetadataPackPointer constraintType = result.getType();
|
|
assert(constraintType.getLifetime() == PackLifetime::OnHeap);
|
|
|
|
if (subjectType.getNumElements() != constraintType.getNumElements()) {
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"mismatched pack lengths in same-type pack requirement %.*s: %lu vs %lu",
|
|
(int)req.getParam().size(), req.getParam().data(),
|
|
subjectType.getNumElements(), constraintType.getNumElements());
|
|
}
|
|
|
|
for (size_t i = 0, e = subjectType.getNumElements(); i < e; ++i) {
|
|
auto *subjectElt = subjectType.getElements()[i];
|
|
auto *constraintElt = constraintType.getElements()[i];
|
|
|
|
if (subjectElt != constraintElt) {
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"subject type %.*s does not match %.*s at pack index %lu",
|
|
(int)req.getParam().size(),
|
|
req.getParam().data(), (int)req.getMangledTypeName().size(),
|
|
req.getMangledTypeName().data(), i);
|
|
}
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::Layout: {
|
|
for (size_t i = 0, e = subjectType.getNumElements(); i < e; ++i) {
|
|
const Metadata *elt = subjectType.getElements()[i];
|
|
if (auto result = satisfiesLayoutConstraint(req, elt))
|
|
return result;
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::BaseClass: {
|
|
// Demangle the base type under the given substitutions.
|
|
auto result = swift_getTypeByMangledName(
|
|
MetadataState::Abstract, req.getMangledTypeName(),
|
|
extraArguments.data(), substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
auto baseType = result.getType().getMetadata();
|
|
|
|
// Check that each pack element inherits from the base class.
|
|
for (size_t i = 0, e = subjectType.getNumElements(); i < e; ++i) {
|
|
const Metadata *elt = subjectType.getElements()[i];
|
|
|
|
if (!isSubclassOrExistential(elt, baseType))
|
|
return TYPE_LOOKUP_ERROR_FMT(
|
|
"%.*s is not subclass of %.*s at pack index %lu",
|
|
(int)req.getParam().size(),
|
|
req.getParam().data(), (int)req.getMangledTypeName().size(),
|
|
req.getMangledTypeName().data(), i);
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameConformance: {
|
|
// FIXME: Implement this check.
|
|
return llvm::None;
|
|
}
|
|
|
|
case GenericRequirementKind::SameShape: {
|
|
auto result = swift::getTypePackByMangledName(
|
|
req.getMangledTypeName(), extraArguments.data(),
|
|
substGenericParam, substWitnessTable);
|
|
if (result.getError())
|
|
return *result.getError();
|
|
MetadataPackPointer otherType = result.getType();
|
|
assert(otherType.getLifetime() == PackLifetime::OnHeap);
|
|
|
|
if (subjectType.getNumElements() != otherType.getNumElements()) {
|
|
return TYPE_LOOKUP_ERROR_FMT("same-shape requirement unsatisfied; "
|
|
"%lu != %lu",
|
|
subjectType.getNumElements(),
|
|
otherType.getNumElements() );
|
|
}
|
|
|
|
return llvm::None;
|
|
}
|
|
}
|
|
|
|
// Unknown generic requirement kind.
|
|
return TYPE_LOOKUP_ERROR_FMT("unknown generic requirement kind %u",
|
|
(unsigned)req.getKind());
|
|
}
|
|
|
|
llvm::Optional<TypeLookupError> swift::_checkGenericRequirements(
|
|
llvm::ArrayRef<GenericRequirementDescriptor> requirements,
|
|
llvm::SmallVectorImpl<const void *> &extraArguments,
|
|
SubstGenericParameterFn substGenericParam,
|
|
SubstDependentWitnessTableFn substWitnessTable) {
|
|
for (const auto &req : requirements) {
|
|
if (req.getFlags().isPackRequirement()) {
|
|
auto error = checkGenericPackRequirement(req, extraArguments,
|
|
substGenericParam,
|
|
substWitnessTable);
|
|
if (error)
|
|
return error;
|
|
} else {
|
|
auto error = checkGenericRequirement(req, extraArguments,
|
|
substGenericParam,
|
|
substWitnessTable);
|
|
if (error)
|
|
return error;
|
|
}
|
|
}
|
|
|
|
// Success!
|
|
return llvm::None;
|
|
}
|
|
|
|
const Metadata *swift::findConformingSuperclass(
|
|
const Metadata *type,
|
|
const ProtocolConformanceDescriptor *conformance) {
|
|
// Figure out which type we're looking for.
|
|
ConformanceCandidate candidate(*conformance);
|
|
|
|
const Metadata *conformingType = std::get<const Metadata *>(
|
|
candidate.getMatchingType(type, true /*instantiateSuperclassMetadata*/));
|
|
assert(conformingType);
|
|
return conformingType;
|
|
}
|
|
|
|
#define OVERRIDE_PROTOCOLCONFORMANCE COMPATIBILITY_OVERRIDE
|
|
#include COMPATIBILITY_OVERRIDE_INCLUDE_PATH
|