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stdlib/runtime: stdlib casts to existentials: correctly project the buffer as

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rdar://17628745


Swift SVN r20024
This commit is contained in:
Dmitri Hrybenko
2014-07-16 15:17:46 +00:00
parent 7f80ba7de6
commit d125ac1e24
5 changed files with 231 additions and 61 deletions
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100
stdlib/runtime/Casting.cpp
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@@ -1384,14 +1384,24 @@ recur:
}
}
static const Metadata *getDynamicTypeMetadata(OpaqueValue *value,
const Metadata *type) {
if (type->getKind() == MetadataKind::Existential) {
const auto existentialMetadata =
static_cast<const ExistentialTypeMetadata *>(type);
return existentialMetadata->getDynamicType(value);
}
return type;
/// Given a possibly-existential value, find its dynamic type and the
/// address of its storage.
static bool findDynamicValueAndType_NoMetatypes(OpaqueValue *value,
const Metadata *type,
OpaqueValue *&outValue,
const Metadata *&outType) {
// FIXME: workaround for <rdar://problem/17695211>.
//
// Filter out metatypes because 'findDynamicValueAndType' can crash.
// Metatypes sometimes contain garbage metadata pointers.
//
// When the bug is fixed, replace calls to this function with direct calls to
// 'findDynamicValueAndType'.
if (type->getKind() == MetadataKind::Metatype ||
type->getKind() == MetadataKind::ExistentialMetatype)
return false;
findDynamicValueAndType(value, type, outValue, outType);
return true;
}
static const void *
@@ -1425,12 +1435,18 @@ extern "C" bool
swift_stdlib_conformsToProtocol(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
// 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 = getDynamicTypeMetadata(sourceValue, sourceType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
// Find the actual type of the source.
OpaqueValue *sourceDynamicValue;
const Metadata *sourceDynamicType;
if (!findDynamicValueAndType_NoMetatypes(sourceValue, sourceType,
sourceDynamicValue,
sourceDynamicType)) {
sourceType->vw_destroy(sourceValue);
return false;
}
auto vw = findWitnessTableForDynamicCastToExistential1(
sourceDynamicValue, sourceDynamicType, destType);
sourceType->vw_destroy(sourceValue);
return vw != nullptr;
}
@@ -1448,24 +1464,32 @@ extern "C" FixedOpaqueExistentialContainer<1>
swift_stdlib_dynamicCastToExistential1Unconditional(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
// 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 = getDynamicTypeMetadata(sourceValue, sourceType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
// Find the actual type of the source.
OpaqueValue *sourceDynamicValue;
const Metadata *sourceDynamicType;
if (!findDynamicValueAndType_NoMetatypes(sourceValue, sourceType,
sourceDynamicValue,
sourceDynamicType)) {
swift::crash("Swift dynamic cast failed: "
"type (metatype) does not conform to the protocol");
}
auto vw = findWitnessTableForDynamicCastToExistential1(
sourceDynamicValue, sourceDynamicType, destType);
if (!vw)
swift::crash("Swift dynamic cast failed: "
"type does not conform to the protocol");
// Note: the 'sourceType' has been adjusted to the dynamic type of the value.
// It is important so that we don't return a value with Existential metadata.
// Note: use the 'sourceDynamicType', which has been adjusted to the
// dynamic type of the value. It is important so that we don't return a
// value with Existential metadata.
using box = OpaqueExistentialBox<1>;
box::Container outValue;
outValue.Header.Type = sourceType;
outValue.Header.Type = sourceDynamicType;
outValue.WitnessTables[0] = vw;
sourceType->vw_initializeBufferWithTake(outValue.getBuffer(), sourceValue);
sourceDynamicType->vw_initializeBufferWithTake(outValue.getBuffer(),
sourceDynamicValue);
return outValue;
}
@@ -1493,25 +1517,33 @@ _TFSs26_injectNothingIntoOptionalU__FT_GSqQ__(const Metadata *T);
extern "C" OpaqueExistentialContainer swift_stdlib_dynamicCastToExistential1(
OpaqueValue *sourceValue, const Metadata *_destType,
const Metadata *sourceType, const Metadata *destType) {
// 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 = getDynamicTypeMetadata(sourceValue, sourceType);
auto vw = findWitnessTableForDynamicCastToExistential1(sourceValue,
sourceType, destType);
// Find the actual type of the source.
OpaqueValue *sourceDynamicValue;
const Metadata *sourceDynamicType;
if (!findDynamicValueAndType_NoMetatypes(sourceValue, sourceType,
sourceDynamicValue,
sourceDynamicType)) {
sourceType->vw_destroy(sourceValue);
return _TFSs26_injectNothingIntoOptionalU__FT_GSqQ__(destType);
}
auto vw = findWitnessTableForDynamicCastToExistential1(
sourceDynamicValue, sourceDynamicType, destType);
if (!vw) {
sourceType->vw_destroy(sourceValue);
return _TFSs26_injectNothingIntoOptionalU__FT_GSqQ__(destType);
}
// Note: the 'sourceType' has been adjusted to the dynamic type of the value.
// It is important so that we don't return a value with Existential metadata.
// Note: use the 'sourceDynamicType', which has been adjusted to the
// dynamic type of the value. It is important so that we don't return a
// value with Existential metadata.
using box = OpaqueExistentialBox<1>;
box::Container outValue;
outValue.Header.Type = sourceType;
outValue.Header.Type = sourceDynamicType;
outValue.WitnessTables[0] = vw;
sourceType->vw_initializeBufferWithTake(outValue.getBuffer(), sourceValue);
sourceDynamicType->vw_initializeBufferWithTake(outValue.getBuffer(),
sourceDynamicValue);
return _TFSs24_injectValueIntoOptionalU__FQ_GSqQ__(
reinterpret_cast<OpaqueValue *>(&outValue), destType);