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stdlib/runtime: teach DynamicCastToExistential1 to handle source values that

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are existentials

rdar://16925792


Swift SVN r18107
This commit is contained in:
Dmitri Hrybenko
2014-05-15 16:32:13 +00:00
parent bf8fbfc32e
commit 2a956966ac
3 changed files with 201 additions and 11 deletions
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21
stdlib/runtime/Metadata.cpp
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@@ -2512,7 +2512,8 @@ recur:
}
static const void *
findWitnessTableForDynamicCastToExistential1(const Metadata *sourceType,
findWitnessTableForDynamicCastToExistential1(OpaqueValue *sourceValue,
const Metadata *sourceType,
const Metadata *destType) {
if (destType->getKind() != MetadataKind::Existential)
swift::crash("Swift protocol conformance check failed: "
@@ -2527,6 +2528,15 @@ findWitnessTableForDynamicCastToExistential1(const Metadata *sourceType,
auto destProtocolDescriptor = destExistentialMetadata->Protocols[0];
if (sourceType->getKind() == MetadataKind::Existential) {
const auto sourceExistentialMetadata =
static_cast<const ExistentialTypeMetadata *>(sourceType);
// Existentials don't carry complete type information about the value, but
// it is necessary to find the witness tables. Find the dynamic type and
// use it instead.
sourceType = sourceExistentialMetadata->getDynamicType(sourceValue);
}
return swift_conformsToProtocol(sourceType, destProtocolDescriptor, nullptr);
}
@@ -2537,7 +2547,8 @@ extern "C" bool
swift_stdlib_conformsToProtocol(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
auto vw = findWitnessTableForDynamicCastToExistential1(sourceType, destType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
sourceType->vw_destroy(sourceValue);
return vw != nullptr;
}
@@ -2550,7 +2561,8 @@ extern "C" FixedOpaqueExistentialContainer<1>
swift_stdlib_dynamicCastToExistential1Unconditional(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
auto vw = findWitnessTableForDynamicCastToExistential1(sourceType, destType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
if (!vw)
swift::crash("Swift dynamic cast failed: "
"type does not conform to the protocol");
@@ -2586,7 +2598,8 @@ _TFSs26_injectNothingIntoOptionalU__FT_GSqQ__(const Metadata *T);
extern "C" OpaqueExistentialContainer swift_stdlib_dynamicCastToExistential1(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
auto vw = findWitnessTableForDynamicCastToExistential1(sourceType, destType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
if (!vw) {
sourceType->vw_destroy(sourceValue);
return _TFSs26_injectNothingIntoOptionalU__FT_GSqQ__(destType);