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[Runtime] Allow overrides or swift_getAssociated(Type|Conformance)Witness #20592

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merged 2 commits into from
Nov 15, 2018
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[Runtime] Allow overrides or swift_getAssociated(Type|Conformance)Witness #20592

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dc73c67
[Runtime] Allow overrides or swift_getAssociated(Type|Conformance)Wit…
DougGregor Nov 15, 2018
7594762
[Runtime] Update unit test for swift_getAssociated(Type|Conformance)S…
DougGregor Nov 15, 2018
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21 changes: 21 additions & 0 deletions stdlib/public/runtime/CompatibilityOverride.def
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@
# define OVERRIDE_FOREIGN OVERRIDE
# define OVERRIDE_PROTOCOLCONFORMANCE OVERRIDE
# define OVERRIDE_KEYPATH OVERRIDE
# define OVERRIDE_WITNESSTABLE OVERRIDE
#else
# ifndef OVERRIDE_METADATALOOKUP
# define OVERRIDE_METADATALOOKUP(...)
Expand All @@ -63,6 +64,9 @@
# ifndef OVERRIDE_KEYPATH
# define OVERRIDE_KEYPATH(...)
# endif
# ifndef OVERRIDE_WITNESSTABLE
# define OVERRIDE_WITNESSTABLE(...)
# endif
#endif

OVERRIDE_METADATALOOKUP(getTypeByMangledName, const Metadata *,
Expand Down Expand Up @@ -140,6 +144,22 @@ OVERRIDE_KEYPATH(getKeyPath, const HeapObject *, , swift::,
(const void *pattern, const void *arguments),
(pattern, arguments))

OVERRIDE_WITNESSTABLE(getAssociatedTypeWitnessSlow, MetadataResponse,
SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL, swift::,
(MetadataRequest request, WitnessTable *wtable,
const Metadata *conformingType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocType),
(request, wtable, conformingType, reqBase, assocType))

OVERRIDE_WITNESSTABLE(getAssociatedConformanceWitnessSlow, const WitnessTable *,
SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL, swift::,
(WitnessTable *wtable, const Metadata *conformingType,
const Metadata *assocType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocConformance),
(wtable, conformingType, assocType, reqBase,
assocConformance))
#if SWIFT_OBJC_INTEROP

OVERRIDE_OBJC(dynamicCastObjCClass, const void *, , swift::,
Expand Down Expand Up @@ -183,3 +203,4 @@ OVERRIDE_FOREIGN(dynamicCastForeignClassUnconditional, const void *, , swift::,
#undef OVERRIDE_FOREIGN
#undef OVERRIDE_PROTOCOLCONFORMANCE
#undef OVERRIDE_KEYPATH
#undef OVERRIDE_WITNESSTABLE
52 changes: 46 additions & 6 deletions stdlib/public/runtime/Metadata.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4053,13 +4053,13 @@ static StringRef findAssociatedTypeName(const ProtocolDescriptor *protocol,
return StringRef();
}

MetadataResponse
swift::swift_getAssociatedTypeWitness(MetadataRequest request,
static MetadataResponse
swift_getAssociatedTypeWitnessSlowImpl(
MetadataRequest request,
WitnessTable *wtable,
const Metadata *conformingType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocType) {

#ifndef NDEBUG
{
const ProtocolConformanceDescriptor *conformance = wtable->Description;
Expand All @@ -4077,7 +4077,7 @@ swift::swift_getAssociatedTypeWitness(MetadataRequest request,
unsigned witnessIndex = assocType - reqBase;
auto witness = ((const void* const *)wtable)[witnessIndex];
if (LLVM_LIKELY((uintptr_t(witness) &
ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
// Cached metadata pointers are always complete.
return MetadataResponse{(const Metadata *)witness, MetadataState::Complete};
}
Expand Down Expand Up @@ -4158,7 +4158,26 @@ swift::swift_getAssociatedTypeWitness(MetadataRequest request,
return response;
}

const WitnessTable *swift::swift_getAssociatedConformanceWitness(
MetadataResponse
swift::swift_getAssociatedTypeWitness(MetadataRequest request,
WitnessTable *wtable,
const Metadata *conformingType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocType) {
// If the low bit of the witness is clear, it's already a metadata pointer.
unsigned witnessIndex = assocType - reqBase;
auto witness = ((const void* const *)wtable)[witnessIndex];
if (LLVM_LIKELY((uintptr_t(witness) &
ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
// Cached metadata pointers are always complete.
return MetadataResponse{(const Metadata *)witness, MetadataState::Complete};
}

return swift_getAssociatedTypeWitnessSlow(request, wtable, conformingType,
reqBase, assocType);
}

static const WitnessTable *swift_getAssociatedConformanceWitnessSlowImpl(
WitnessTable *wtable,
const Metadata *conformingType,
const Metadata *assocType,
Expand All @@ -4177,7 +4196,7 @@ const WitnessTable *swift::swift_getAssociatedConformanceWitness(
}
#endif

// Call the access function.
// Retrieve the witness.
unsigned witnessIndex = assocConformance - reqBase;
auto witness = ((const void* const *)wtable)[witnessIndex];
// Fast path: we've already resolved this to a witness table, so return it.
Expand Down Expand Up @@ -4222,6 +4241,26 @@ const WitnessTable *swift::swift_getAssociatedConformanceWitness(
swift_runtime_unreachable("Invalid mangled associate conformance");
}

const WitnessTable *swift::swift_getAssociatedConformanceWitness(
WitnessTable *wtable,
const Metadata *conformingType,
const Metadata *assocType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocConformance) {
// Retrieve the witness.
unsigned witnessIndex = assocConformance - reqBase;
auto witness = ((const void* const *)wtable)[witnessIndex];
// Fast path: we've already resolved this to a witness table, so return it.
if (LLVM_LIKELY((uintptr_t(witness) &
ProtocolRequirementFlags::AssociatedTypeMangledNameBit) == 0)) {
return static_cast<const WitnessTable *>(witness);
}

return swift_getAssociatedConformanceWitnessSlow(wtable, conformingType,
assocType, reqBase,
assocConformance);
}

/***************************************************************************/
/*** Recursive metadata dependencies ***************************************/
/***************************************************************************/
Expand Down Expand Up @@ -4842,4 +4881,5 @@ const HeapObject *swift_getKeyPathImpl(const void *pattern,
const void *arguments);

#define OVERRIDE_KEYPATH COMPATIBILITY_OVERRIDE
#define OVERRIDE_WITNESSTABLE COMPATIBILITY_OVERRIDE
#include "CompatibilityOverride.def"
34 changes: 34 additions & 0 deletions stdlib/public/runtime/Private.h
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Original file line number Diff line number Diff line change
Expand Up @@ -457,6 +457,40 @@ class TypeInfo {
const Metadata *findConformingSuperclass(
const Metadata *type,
const ProtocolConformanceDescriptor *conformance);

/// Retrieve an associated type witness from the given witness table.
///
/// \param wtable The witness table.
/// \param conformingType Metadata for the conforming type.
/// \param reqBase "Base" requirement used to compute the witness index
/// \param assocType Associated type descriptor.
///
/// \returns metadata for the associated type witness.
SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
MetadataResponse swift_getAssociatedTypeWitnessSlow(
MetadataRequest request,
WitnessTable *wtable,
const Metadata *conformingType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocType);

/// Retrieve an associated conformance witness table from the given witness
/// table.
///
/// \param wtable The witness table.
/// \param conformingType Metadata for the conforming type.
/// \param assocType Metadata for the associated type.
/// \param reqBase "Base" requirement used to compute the witness index
/// \param assocConformance Associated conformance descriptor.
///
/// \returns corresponding witness table.
SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
const WitnessTable *swift_getAssociatedConformanceWitnessSlow(
WitnessTable *wtable,
const Metadata *conformingType,
const Metadata *assocType,
const ProtocolRequirement *reqBase,
const ProtocolRequirement *assocConformance);
} // end namespace swift

#endif /* SWIFT_RUNTIME_PRIVATE_H */
29 changes: 28 additions & 1 deletion unittests/runtime/CompatibilityOverride.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -24,14 +24,25 @@ using namespace swift;
bool EnableOverride;
bool Ran;

namespace {
template<typename T>
T getEmptyValue() {
return (T)0;
}

template<>
MetadataResponse getEmptyValue<MetadataResponse>() {
return MetadataResponse{nullptr, MetadataState::Complete};
}
}

#define OVERRIDE(name, ret, attrs, namespace, typedArgs, namedArgs) \
static ret name ## Override(COMPATIBILITY_UNPAREN typedArgs, \
Original_ ## name originalImpl) { \
if (!EnableOverride) \
return originalImpl namedArgs; \
Ran = true; \
return (ret)0; \
return getEmptyValue<ret>(); \
}
#include "../../stdlib/public/runtime/CompatibilityOverride.def"

Expand Down Expand Up @@ -164,4 +175,20 @@ TEST_F(CompatibilityOverrideTest, test_swift_conformsToProtocol) {
ASSERT_EQ(Result, nullptr);
}

TEST_F(CompatibilityOverrideTest, test_swift_getAssociatedTypeWitnessSlow) {
auto Result = swift_getAssociatedTypeWitnessSlow(MetadataState::Complete,
nullptr, nullptr,
nullptr, nullptr);
ASSERT_EQ(Result.Value, nullptr);
ASSERT_EQ(Result.State, MetadataState::Complete);
}

TEST_F(CompatibilityOverrideTest,
test_swift_getAssociatedConformanceWitnessSlow) {
auto Result = swift_getAssociatedConformanceWitnessSlow(
nullptr, nullptr, nullptr,
nullptr, nullptr);
ASSERT_EQ(Result, nullptr);
}

#endif