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Merged
merged 4 commits into from
Dec 8, 2017
Merged

Class resilience part 3 #13312

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0fa7440
IRGen/Runtime: Remove old class metadata relocation mechanism
slavapestov Dec 7, 2017
c19478a
IRGen: Offset::offsetBy() should take an Offset and a Size
slavapestov Dec 1, 2017
176efde
IRGen: Redo fill ops
slavapestov Dec 5, 2017
5dcc6b1
IRGen: Count number of immediate class members in ClassMetadataLayout
slavapestov Dec 5, 2017
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13 changes: 4 additions & 9 deletions include/swift/Runtime/Metadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2869,16 +2869,11 @@ void swift_initStructMetadata_UniversalStrategy(size_t numFields,

/// Initialize the field offset vector for a dependent-layout class, using the
/// "Universal" layout strategy.
///
/// This will relocate the metadata if it doesn't have enough space
/// for its superclass. Note that swift_allocateGenericClassMetadata will
/// never produce a metadata that requires relocation.
SWIFT_RUNTIME_EXPORT
ClassMetadata *
swift_initClassMetadata_UniversalStrategy(ClassMetadata *self,
size_t numFields,
const TypeLayout * const *fieldTypes,
size_t *fieldOffsets);
void swift_initClassMetadata_UniversalStrategy(ClassMetadata *self,
size_t numFields,
const TypeLayout * const *fieldTypes,
size_t *fieldOffsets);

/// \brief Fetch a uniqued metadata for a metatype type.
SWIFT_RUNTIME_EXPORT
Expand Down
10 changes: 5 additions & 5 deletions include/swift/Runtime/RuntimeFunctions.def
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Expand Up @@ -946,13 +946,13 @@ FUNCTION(GetExistentialMetadata,
ATTRS(NoUnwind, ReadOnly))

// struct FieldInfo { size_t Size; size_t AlignMask; };
// Metadata *swift_initClassMetadata_UniversalStrategy(Metadata *self,
// size_t numFields,
// TypeLayout * const *fieldTypes,
// size_t *fieldOffsets);
// void swift_initClassMetadata_UniversalStrategy(Metadata *self,
// size_t numFields,
// TypeLayout * const *fieldTypes,
// size_t *fieldOffsets);
FUNCTION(InitClassMetadataUniversal,
swift_initClassMetadata_UniversalStrategy, DefaultCC,
RETURNS(TypeMetadataPtrTy),
RETURNS(VoidTy),
ARGS(TypeMetadataPtrTy, SizeTy,
Int8PtrPtrTy->getPointerTo(),
SizeTy->getPointerTo()),
Expand Down
66 changes: 23 additions & 43 deletions lib/IRGen/GenMeta.cpp
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Expand Up @@ -2758,8 +2758,6 @@ namespace {
struct FillOp {
CanType Type;
Optional<ProtocolConformanceRef> Conformance;
Size ToOffset;
bool IsRelative;
};

SmallVector<FillOp, 8> FillOps;
Expand Down Expand Up @@ -2836,7 +2834,10 @@ namespace {
// fill indexes are word-indexed.
Address metadataWords(IGF.Builder.CreateBitCast(metadataValue, IGM.Int8PtrPtrTy),
IGM.getPointerAlignment());


auto genericReqtOffset = IGM.getMetadataLayout(Target)
.getGenericRequirementsOffset(IGF);

for (auto &fillOp : FillOps) {
llvm::Value *value;
if (fillOp.Conformance) {
Expand All @@ -2846,20 +2847,12 @@ namespace {
}

auto dest = createPointerSizedGEP(IGF, metadataWords,
fillOp.ToOffset - AddressPoint);

// A far relative indirectable pointer.
if (fillOp.IsRelative) {
dest = IGF.Builder.CreateElementBitCast(dest,
IGM.FarRelativeAddressTy);
IGF.emitStoreOfRelativeIndirectablePointer(value, dest,
/*isFar*/ true);
genericReqtOffset.getStatic());
genericReqtOffset = genericReqtOffset.offsetBy(
IGF, IGM.getPointerSize());

// A direct pointer.
} else {
value = IGF.Builder.CreateBitCast(value, IGM.Int8PtrTy);
IGF.Builder.CreateStore(value, dest);
}
value = IGF.Builder.CreateBitCast(value, IGM.Int8PtrTy);
IGF.Builder.CreateStore(value, dest);
}

// Initialize the instantiated dependent value witness table, if we have
Expand Down Expand Up @@ -2894,12 +2887,6 @@ namespace {
return f;
}

void addFillOp(CanType type, Optional<ProtocolConformanceRef> conf,
bool isRelative) {
FillOps.push_back({type, conf, getNextOffsetFromTemplateHeader(),
isRelative });
}

public:
void createMetadataAccessFunction() {
(void) getGenericTypeMetadataAccessFunction(IGM, Target, ForDefinition);
Expand Down Expand Up @@ -2981,14 +2968,14 @@ namespace {

template <class... T>
void addGenericArgument(CanType type, T &&...args) {
addFillOp(type, None, /*relative*/ false);
FillOps.push_back({type, None});
super::addGenericArgument(type, std::forward<T>(args)...);
}

template <class... T>
void addGenericWitnessTable(CanType type, ProtocolConformanceRef conf,
T &&...args) {
addFillOp(type, conf, /*relative*/ false);
FillOps.push_back({type, conf});
super::addGenericWitnessTable(type, conf, std::forward<T>(args)...);
}

Expand Down Expand Up @@ -3021,11 +3008,10 @@ namespace {
};
} // end anonymous namespace

llvm::Value *
irgen::emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
llvm::Value *vwtable) {
void irgen::emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
llvm::Value *vwtable) {
auto *target = T.getNominalOrBoundGenericNominal();
llvm::Value *fieldVector
= emitAddressOfFieldOffsetVector(IGF, metadata, target)
Expand Down Expand Up @@ -3062,9 +3048,9 @@ irgen::emitInitializeFieldOffsetVector(IRGenFunction &IGF,

if (isa<ClassDecl>(target)) {
assert(vwtable == nullptr);
metadata = IGF.Builder.CreateCall(IGF.IGM.getInitClassMetadataUniversalFn(),
{metadata, numFields,
fields.getAddress(), fieldVector});
IGF.Builder.CreateCall(IGF.IGM.getInitClassMetadataUniversalFn(),
{metadata, numFields,
fields.getAddress(), fieldVector});
} else {
assert(isa<StructDecl>(target));
IGF.Builder.CreateCall(IGF.IGM.getInitStructMetadataUniversalFn(),
Expand All @@ -3074,8 +3060,6 @@ irgen::emitInitializeFieldOffsetVector(IRGenFunction &IGF,

IGF.Builder.CreateLifetimeEnd(fields,
IGF.IGM.getPointerSize() * storedProperties.size());

return metadata;
}

// Classes
Expand Down Expand Up @@ -3489,11 +3473,9 @@ namespace {
}

llvm::Value *emitFinishInitializationOfClassMetadata(IRGenFunction &IGF,
llvm::Value *metadata) {
llvm::Value *metadata) {
// We assume that we've already filled in the class's generic arguments.
// We need to:
// - relocate the metadata to accommodate the superclass,
// if something in our hierarchy is resilient to us;
// - fill out the subclass's field offset vector, if its layout
// wasn't fixed;
// - copy field offsets and generic arguments from higher in the
Expand All @@ -3508,9 +3490,9 @@ namespace {
if (doesClassMetadataRequireDynamicInitialization(IGF.IGM, Target)) {
auto classTy = Target->getDeclaredTypeInContext()->getCanonicalType();
auto loweredClassTy = IGF.IGM.getLoweredType(classTy);
metadata = emitInitializeFieldOffsetVector(IGF, loweredClassTy,
metadata,
/*vwtable=*/nullptr);
emitInitializeFieldOffsetVector(IGF, loweredClassTy,
metadata,
/*vwtable=*/nullptr);
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So we're assuming that the superclass has been relocated already. That's a nice simplification. The runtime will do this?

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And if so, presumably it can copy field offsets and generic arguments higher in the hierarchy, so we can strike that bit from the comment, too?

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The relocation is handled in the next PR ("part 4").

Copying field offsets and generic arguments from higher up in the hierarchy is already implemented by swift_initClassMetadata_UniversalStrategy(), since we already have to do it for generic classes, where the generic arguments and field offsets are always just null in the template.


// Realizing the class with the ObjC runtime will copy back to the
// field offset globals for us; but if ObjC interop is disabled, we
Expand Down Expand Up @@ -3742,9 +3724,7 @@ namespace {
IGF.Builder.CreateStore(superclassMetadata, superField);
}

metadata = emitFinishInitializationOfClassMetadata(IGF, metadata);

return metadata;
return emitFinishInitializationOfClassMetadata(IGF, metadata);
}
};

Expand Down
8 changes: 4 additions & 4 deletions lib/IRGen/GenMeta.h
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Expand Up @@ -255,10 +255,10 @@ namespace irgen {

/// \brief Initialize the field offset vector within the given class or struct
/// metadata.
llvm::Value *emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
llvm::Value *vwtable);
void emitInitializeFieldOffsetVector(IRGenFunction &IGF,
SILType T,
llvm::Value *metadata,
llvm::Value *vwtable);

/// Adjustment indices for the address points of various metadata.
/// Size is in words.
Expand Down
2 changes: 1 addition & 1 deletion lib/IRGen/IRGen.h
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Expand Up @@ -484,7 +484,7 @@ class Offset {
}

llvm::Value *getAsValue(IRGenFunction &IGF) const;
Offset offsetBy(IRGenFunction &IGF, Offset other) const;
Offset offsetBy(IRGenFunction &IGF, Size other) const;
};

} // end namespace irgen
Expand Down
9 changes: 5 additions & 4 deletions lib/IRGen/IRGenFunction.cpp
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Expand Up @@ -394,11 +394,12 @@ llvm::Value *Offset::getAsValue(IRGenFunction &IGF) const {
}
}

Offset Offset::offsetBy(IRGenFunction &IGF, Offset other) const {
if (isStatic() && other.isStatic()) {
return Offset(getStatic() + other.getStatic());
Offset Offset::offsetBy(IRGenFunction &IGF, Size other) const {
if (isStatic()) {
return Offset(getStatic() + other);
}
return Offset(IGF.Builder.CreateAdd(getDynamic(), other.getDynamic()));
auto otherVal = llvm::ConstantInt::get(IGF.IGM.SizeTy, other.getValue());
return Offset(IGF.Builder.CreateAdd(getDynamic(), otherVal));
}

Address IRGenFunction::emitAddressAtOffset(llvm::Value *base, Offset offset,
Expand Down
35 changes: 31 additions & 4 deletions lib/IRGen/MetadataLayout.cpp
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Expand Up @@ -147,7 +147,7 @@ static llvm::Value *emitLoadOfGenericRequirement(IRGenFunction &IGF,
llvm::Type *reqtTy) {
auto offset =
IGF.IGM.getMetadataLayout(decl).getGenericRequirementsOffset(IGF);
offset = offset.offsetBy(IGF, Offset(reqtIndex * IGF.IGM.getPointerSize()));
offset = offset.offsetBy(IGF, Size(reqtIndex * IGF.IGM.getPointerSize()));

auto slot = IGF.emitAddressAtOffset(metadata, offset, reqtTy,
IGF.IGM.getPointerAlignment());
Expand Down Expand Up @@ -203,7 +203,7 @@ Address irgen::emitAddressOfFieldOffsetVector(IRGenFunction &IGF,
/********************************** CLASSES ***********************************/

ClassMetadataLayout::ClassMetadataLayout(IRGenModule &IGM, ClassDecl *decl)
: NominalMetadataLayout(Kind::Class) {
: NominalMetadataLayout(Kind::Class), NumImmediateMembers(0) {

struct Scanner : LayoutScanner<Scanner, ClassMetadataScanner> {
using super = LayoutScanner;
Expand All @@ -228,9 +228,26 @@ ClassMetadataLayout::ClassMetadataLayout(IRGenModule &IGM, ClassDecl *decl)
super::noteStartOfGenericRequirements(forClass);
}

void addGenericWitnessTable(CanType argType, ProtocolConformanceRef conf,
ClassDecl *forClass) {
if (forClass == Target) {
Layout.NumImmediateMembers++;
}
super::addGenericWitnessTable(argType, conf, forClass);
}

void addGenericArgument(CanType argType, ClassDecl *forClass) {
if (forClass == Target) {
Layout.NumImmediateMembers++;
}
super::addGenericArgument(argType, forClass);
}

void addMethod(SILDeclRef fn) {
if (fn.getDecl()->getDeclContext() == Target)
if (fn.getDecl()->getDeclContext() == Target) {
Layout.NumImmediateMembers++;
Layout.MethodInfos.try_emplace(fn, getNextOffset());
}
super::addMethod(fn);
}

Expand All @@ -241,11 +258,21 @@ ClassMetadataLayout::ClassMetadataLayout(IRGenModule &IGM, ClassDecl *decl)
}

void addFieldOffset(VarDecl *field) {
if (field->getDeclContext() == Target)
if (field->getDeclContext() == Target) {
Layout.NumImmediateMembers++;
Layout.FieldOffsets.try_emplace(field, getNextOffset());
}
super::addFieldOffset(field);
}

void addFieldOffsetPlaceholders(MissingMemberDecl *placeholder) {
if (placeholder->getDeclContext() == Target) {
Layout.NumImmediateMembers +=
placeholder->getNumberOfFieldOffsetVectorEntries();
}
super::addFieldOffsetPlaceholders(placeholder);
}

void addVTableEntries(ClassDecl *forClass) {
if (forClass == Target)
Layout.VTableOffset = getNextOffset();
Expand Down
10 changes: 10 additions & 0 deletions lib/IRGen/MetadataLayout.h
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Expand Up @@ -168,6 +168,9 @@ class ClassMetadataLayout : public NominalMetadataLayout {
/// The start of the field-offset vector.
StoredOffset FieldOffsetVector;

/// The number of members to add after superclass metadata.
unsigned NumImmediateMembers;

const StoredMethodInfo &getStoredMethodInfo(SILDeclRef method) const {
auto it = MethodInfos.find(method);
assert(it != MethodInfos.end());
Expand Down Expand Up @@ -222,6 +225,13 @@ class ClassMetadataLayout : public NominalMetadataLayout {

Offset getFieldOffsetVectorOffset(IRGenFunction &IGF) const;

/// The number of members to add after superclass metadata. The size of
/// this metadata is the superclass size plus the number of immediate
/// members in the class itself.
unsigned getNumImmediateMembers() const {
return NumImmediateMembers;
}

static bool classof(const MetadataLayout *layout) {
return layout->getKind() == Kind::Class;
}
Expand Down
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