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Merged
merged 4 commits into from
Aug 24, 2018
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Use a true-const pattern to initialize non-generic resilient class metadata #18893

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4a23d3c
IRGen: Rename emitInitializeMetadata() to emitInitializeValueMetadata()
slavapestov Aug 22, 2018
d562344
IRGen: Another small cleanup for class metadata emission
slavapestov Aug 22, 2018
120be25
IRGen: Metadata patterns are always true-const
slavapestov Aug 23, 2018
03cb6d1
IRGen/Runtime: Use a true-const pattern to initialize non-generic res…
slavapestov Aug 22, 2018
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49 changes: 42 additions & 7 deletions include/swift/ABI/Metadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3085,7 +3085,7 @@ class TargetGenericMetadataPatternTrailingObjects :
}
};

/// An instantiation pattern for class metadata.
/// An instantiation pattern for generic class metadata.
template <typename Runtime>
struct TargetGenericClassMetadataPattern final :
TargetGenericMetadataPattern<Runtime>,
Expand Down Expand Up @@ -3138,7 +3138,7 @@ struct TargetGenericClassMetadataPattern final :
using GenericClassMetadataPattern =
TargetGenericClassMetadataPattern<InProcess>;

/// An instantiation pattern for value metadata.
/// An instantiation pattern for generic value metadata.
template <typename Runtime>
struct TargetGenericValueMetadataPattern final :
TargetGenericMetadataPattern<Runtime>,
Expand Down Expand Up @@ -3316,10 +3316,43 @@ struct TargetInPlaceValueMetadataCache {
using InPlaceValueMetadataCache =
TargetInPlaceValueMetadataCache<InProcess>;

template <typename Runtime>
struct TargetResilientClassMetadataPattern;

/// An instantiation pattern for non-generic resilient class metadata.
/// Used in conjunction with InPlaceValueMetadataInitialization.
using MetadataRelocator =
Metadata *(const TargetTypeContextDescriptor<InProcess> *description);
Metadata *(const TargetTypeContextDescriptor<InProcess> *type,
const TargetResilientClassMetadataPattern<InProcess> *pattern);

/// An instantiation pattern for non-generic resilient class metadata.
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Maybe this should elaborate a bit about the breakdown between the different class-metadata allocation situations.

template <typename Runtime>
struct TargetResilientClassMetadataPattern {
/// If the class descriptor's hasResilientSuperclass() flag is set,
/// this field instead points at a function that allocates metadata
/// with the correct size at runtime.
TargetRelativeDirectPointer<Runtime, MetadataRelocator> RelocationFunction;
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This comment needs to be rewritten, since the "if" clause is now the precondition for this entire structure existing.


/// The heap-destructor function.
TargetRelativeDirectPointer<Runtime, HeapObjectDestroyer> Destroy;

/// The ivar-destructor function.
TargetRelativeDirectPointer<Runtime, ClassIVarDestroyer> IVarDestroyer;

/// The class flags.
ClassFlags Flags;

// The following fields are only present in ObjC interop.

/// Our ClassROData.
TargetRelativeDirectPointer<Runtime, void> Data;

/// Our metaclass.
TargetRelativeDirectPointer<Runtime, TargetAnyClassMetadata<Runtime>> Metaclass;
};

using ResilientClassMetadataPattern =
TargetResilientClassMetadataPattern<InProcess>;

/// The control structure for performing non-trivial initialization of
/// singleton value metadata, which is required when e.g. a non-generic
Expand All @@ -3340,8 +3373,8 @@ struct TargetInPlaceValueMetadataInitialization {
/// If the class descriptor's hasResilientSuperclass() flag is set,
/// this field instead points at a function that allocates metadata
/// with the correct size at runtime.
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This comment needs similar fixing.

TargetRelativeDirectPointer<Runtime, MetadataRelocator>
RelocationFunction;
TargetRelativeDirectPointer<Runtime, TargetResilientClassMetadataPattern<Runtime>>
ResilientPattern;
};

/// The completion function. The pattern will always be null.
Expand All @@ -3358,8 +3391,10 @@ struct TargetInPlaceValueMetadataInitialization {

TargetMetadata<Runtime> *allocate(
const TargetTypeContextDescriptor<Runtime> *description) const {
if (hasRelocationFunction(description))
return RelocationFunction(description);
if (hasRelocationFunction(description)) {
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hasRelocationFunction seems misnamed now; the relocation function is a small aspect of a much bigger picture.

return ResilientPattern->RelocationFunction(description,
ResilientPattern.get());
}
return IncompleteMetadata.get();
}
};
Expand Down
10 changes: 4 additions & 6 deletions include/swift/Runtime/Metadata.h
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Expand Up @@ -574,15 +574,13 @@ void swift_initStructMetadata(StructMetadata *self,
const TypeLayout * const *fieldTypes,
uint32_t *fieldOffsets);

/// Relocate the metadata for a class and copy fields from the given template.
/// The final size of the metadata is calculated at runtime from the size of
/// the superclass metadata together with the given number of immediate
/// members.
/// Allocate the metadata for a class and copy fields from the given pattern.
/// The final size of the metadata is calculated at runtime from the metadata
/// bounds in the class descriptor.
SWIFT_RUNTIME_EXPORT
ClassMetadata *
swift_relocateClassMetadata(ClassDescriptor *descriptor,
ClassMetadata *pattern,
size_t patternSize);
ResilientClassMetadataPattern *pattern);
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This comment should probably clarify that it's part of the construction process for resilient classes and expected to be called from the relocation function as opposed to, say, being a general utility for arbitrary code to use.


/// Initialize the field offset vector for a dependent-layout class, using the
/// "Universal" layout strategy.
Expand Down
13 changes: 6 additions & 7 deletions include/swift/Runtime/RuntimeFunctions.def
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Expand Up @@ -670,19 +670,19 @@ FUNCTION(GetGenericMetadata, swift_getGenericMetadata, SwiftCC,

// Metadata *swift_allocateGenericClassMetadata(ClassDescriptor *type,
// const void * const *arguments,
// const void * const *template);
// const void *template);
FUNCTION(AllocateGenericClassMetadata, swift_allocateGenericClassMetadata,
C_CC, RETURNS(TypeMetadataPtrTy),
ARGS(TypeContextDescriptorPtrTy, Int8PtrPtrTy, Int8PtrPtrTy),
ARGS(TypeContextDescriptorPtrTy, Int8PtrPtrTy, Int8PtrTy),
ATTRS(NoUnwind))

// Metadata *swift_allocateGenericValueMetadata(ValueTypeDescriptor *type,
// const void * const *arguments,
// const void * const *template,
// const void *template,
// size_t extraSize);
FUNCTION(AllocateGenericValueMetadata, swift_allocateGenericValueMetadata,
C_CC, RETURNS(TypeMetadataPtrTy),
ARGS(TypeContextDescriptorPtrTy, Int8PtrPtrTy, Int8PtrPtrTy, SizeTy),
ARGS(TypeContextDescriptorPtrTy, Int8PtrPtrTy, Int8PtrTy, SizeTy),
ATTRS(NoUnwind))

// MetadataResponse swift_checkMetadataState(MetadataRequest request,
Expand Down Expand Up @@ -809,12 +809,11 @@ FUNCTION(GetExistentialMetadata,
ATTRS(NoUnwind, ReadOnly))

// Metadata *swift_relocateClassMetadata(TypeContextDescriptor *descriptor,
// Metadata *pattern,
// size_t patternSize);
// const void *pattern);
FUNCTION(RelocateClassMetadata,
swift_relocateClassMetadata, C_CC,
RETURNS(TypeMetadataPtrTy),
ARGS(TypeContextDescriptorPtrTy, TypeMetadataPtrTy, SizeTy),
ARGS(TypeContextDescriptorPtrTy, Int8PtrTy),
ATTRS(NoUnwind))

// struct FieldInfo { size_t Size; size_t AlignMask; };
Expand Down
12 changes: 7 additions & 5 deletions lib/IRGen/GenDecl.cpp
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Expand Up @@ -3282,8 +3282,9 @@ llvm::GlobalValue *IRGenModule::defineTypeMetadata(CanType concreteType,
assert(init);

if (isPattern) {
assert(isConstant && "Type metadata patterns must be constant");
auto addr = getAddrOfTypeMetadataPattern(concreteType->getAnyNominal(),
isConstant, init, section);
init, section);

return cast<llvm::GlobalValue>(addr);
}
Expand Down Expand Up @@ -3488,12 +3489,11 @@ ConstantReference IRGenModule::getAddrOfTypeMetadata(CanType concreteType,

llvm::Constant *
IRGenModule::getAddrOfTypeMetadataPattern(NominalTypeDecl *D) {
return getAddrOfTypeMetadataPattern(D, false, ConstantInit(), "");
return getAddrOfTypeMetadataPattern(D, ConstantInit(), "");
}

llvm::Constant *
IRGenModule::getAddrOfTypeMetadataPattern(NominalTypeDecl *D,
bool isConstant,
ConstantInit init,
StringRef section) {
if (!init)
Expand All @@ -3502,7 +3502,7 @@ IRGenModule::getAddrOfTypeMetadataPattern(NominalTypeDecl *D,
auto alignment = getPointerAlignment();
LinkEntity entity = LinkEntity::forTypeMetadataPattern(D);
auto addr = getAddrOfLLVMVariable(entity, alignment, init,
Int8PtrTy, DebugTypeInfo());
Int8Ty, DebugTypeInfo());

if (init) {
auto var = cast<llvm::GlobalVariable>(addr);
Expand Down Expand Up @@ -3565,7 +3565,7 @@ IRGenModule::getAddrOfTypeMetadataInstantiationFunction(NominalTypeDecl *D,
/// Generic arguments.
Int8PtrPtrTy,
/// Generic metadata pattern.
Int8PtrPtrTy
Int8PtrTy
};

fnType = llvm::FunctionType::get(TypeMetadataPtrTy, argTys,
Expand All @@ -3577,6 +3577,8 @@ IRGenModule::getAddrOfTypeMetadataInstantiationFunction(NominalTypeDecl *D,
llvm::Type *argTys[] = {
/// Type descriptor.
TypeContextDescriptorPtrTy,
/// Resilient metadata pattern.
Int8PtrTy
};

fnType = llvm::FunctionType::get(TypeMetadataPtrTy, argTys,
Expand Down
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