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[5.6] IRGen: Fix using weak linkage to avoid duplicate metadata by only applying this to PROTOCOL related data #40546

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Dec 15, 2021
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[5.6] IRGen: Fix using weak linkage to avoid duplicate metadata by only applying this to PROTOCOL related data #40546

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144 changes: 80 additions & 64 deletions lib/IRGen/GenClass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1317,22 +1317,25 @@ namespace {
assert(TheExtension && "can't emit category data for a class");
ConstantInitBuilder builder(IGM);
auto fields = builder.beginStruct();
auto internalLinkage = llvm::GlobalVariable::InternalLinkage;

// struct category_t {
// char const *name;
fields.add(IGM.getAddrOfGlobalString(CategoryName));
// const class_t *theClass;
fields.add(getClassMetadataRef());
// const method_list_t *instanceMethods;
emitAndAddMethodList(fields, MethodListKind::InstanceMethods);
emitAndAddMethodList(fields, MethodListKind::InstanceMethods,
internalLinkage);
// const method_list_t *classMethods;
emitAndAddMethodList(fields, MethodListKind::ClassMethods);
emitAndAddMethodList(fields, MethodListKind::ClassMethods,
internalLinkage);
// const protocol_list_t *baseProtocols;
fields.add(buildProtocolList());
fields.add(buildProtocolList(internalLinkage));
// const property_list_t *properties;
fields.add(buildPropertyList(ForClass));
fields.add(buildPropertyList(ForClass, internalLinkage));
// const property_list_t *classProperties;
fields.add(buildPropertyList(ForMetaClass));
fields.add(buildPropertyList(ForMetaClass, internalLinkage));
// uint32_t size;
// FIXME: Clang does this by using non-ad-hoc types for ObjC runtime
// structures.
Expand All @@ -1342,13 +1345,14 @@ namespace {

assert(fields.getNextOffsetFromGlobal() == size);
return buildGlobalVariable(fields, "_CATEGORY_", /*const*/ true,
llvm::GlobalVariable::InternalLinkage);
internalLinkage);
}

llvm::Constant *emitProtocol() {
ConstantInitBuilder builder(IGM);
auto fields = builder.beginStruct();
llvm::SmallString<64> nameBuffer;
auto weakLinkage = llvm::GlobalVariable::WeakAnyLinkage;

assert(isBuildingProtocol() && "not emitting a protocol");

Expand All @@ -1358,17 +1362,20 @@ namespace {
// char const *name;
fields.add(IGM.getAddrOfGlobalString(getEntityName(nameBuffer)));
// const protocol_list_t *baseProtocols;
fields.add(buildProtocolList());
fields.add(buildProtocolList(weakLinkage));
// const method_list_t *requiredInstanceMethods;
emitAndAddMethodList(fields, MethodListKind::InstanceMethods);
emitAndAddMethodList(fields, MethodListKind::InstanceMethods,
weakLinkage);
// const method_list_t *requiredClassMethods;
emitAndAddMethodList(fields, MethodListKind::ClassMethods);
emitAndAddMethodList(fields, MethodListKind::ClassMethods, weakLinkage);
// const method_list_t *optionalInstanceMethods;
emitAndAddMethodList(fields, MethodListKind::OptionalInstanceMethods);
emitAndAddMethodList(fields, MethodListKind::OptionalInstanceMethods,
weakLinkage);
// const method_list_t *optionalClassMethods;
emitAndAddMethodList(fields, MethodListKind::OptionalClassMethods);
emitAndAddMethodList(fields, MethodListKind::OptionalClassMethods,
weakLinkage);
// const property_list_t *properties;
fields.add(buildPropertyList(ForClass));
fields.add(buildPropertyList(ForClass, weakLinkage));

// uint32_t size;
// FIXME: Clang does this by using non-ad-hoc types for ObjC runtime
Expand All @@ -1390,11 +1397,12 @@ namespace {
// const char *demangledName;
fields.addNullPointer(IGM.Int8PtrTy);
// const property_list_t *classProperties;
fields.add(buildPropertyList(ForMetaClass));
fields.add(buildPropertyList(ForMetaClass, weakLinkage));
// };

assert(fields.getNextOffsetFromGlobal() == size);
return buildGlobalVariable(fields, "_PROTOCOL_", /*const*/ true);
return buildGlobalVariable(fields, "_PROTOCOL_", /*const*/ true,
weakLinkage);
}

void emitRODataFields(ConstantStructBuilder &b,
Expand Down Expand Up @@ -1455,12 +1463,14 @@ namespace {
b.add(buildName());

// const method_list_t *baseMethods;
emitAndAddMethodList(b, forMeta ? MethodListKind::ClassMethods
: MethodListKind::InstanceMethods);
emitAndAddMethodList(b,
forMeta ? MethodListKind::ClassMethods
: MethodListKind::InstanceMethods,
llvm::GlobalVariable::InternalLinkage);

// const protocol_list_t *baseProtocols;
// Apparently, this list is the same in the class and the metaclass.
b.add(buildProtocolList());
b.add(buildProtocolList(llvm::GlobalVariable::InternalLinkage));

// const ivar_list_t *ivars;
if (forMeta) {
Expand All @@ -1474,7 +1484,7 @@ namespace {
b.addNullPointer(IGM.Int8PtrTy);

// const property_list_t *baseProperties;
b.add(buildPropertyList(forMeta));
b.add(buildPropertyList(forMeta, llvm::GlobalVariable::InternalLinkage));

// If hasUpdater is true, the metadata update callback goes here.
if (hasUpdater) {
Expand Down Expand Up @@ -1723,7 +1733,8 @@ namespace {

/// Emit the method list and add the pointer to the `builder`.
void emitAndAddMethodList(ConstantInitBuilder::StructBuilder &builder,
MethodListKind kind) {
MethodListKind kind,
llvm::GlobalValue::LinkageTypes linkage) {
ArrayRef<MethodDescriptor> methods;
StringRef namePrefix;
switch (kind) {
Expand All @@ -1748,7 +1759,8 @@ namespace {
namePrefix = "_PROTOCOL_INSTANCE_METHODS_OPT_";
break;
}
llvm::Constant *methodListPtr = buildMethodList(methods, namePrefix);
llvm::Constant *methodListPtr =
buildMethodList(methods, namePrefix, linkage);
builder.add(methodListPtr);
}

Expand All @@ -1769,7 +1781,8 @@ namespace {
}

return buildGlobalVariable(array, "_PROTOCOL_METHOD_TYPES_",
/*const*/ true);
/*const*/ true,
llvm::GlobalVariable::WeakAnyLinkage);
}

void buildExtMethodTypes(ConstantArrayBuilder &array,
Expand All @@ -1792,13 +1805,14 @@ namespace {
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildMethodList(ArrayRef<MethodDescriptor> methods,
StringRef name) {
return buildOptionalList(methods, 3 * IGM.getPointerSize(), name,
/*isConst*/ false,
[&](ConstantArrayBuilder &descriptors,
MethodDescriptor descriptor) {
buildMethod(descriptors, descriptor);
});
StringRef name,
llvm::GlobalValue::LinkageTypes linkage) {
return buildOptionalList(
methods, 3 * IGM.getPointerSize(), name,
/*isConst*/ false, linkage,
[&](ConstantArrayBuilder &descriptors, MethodDescriptor descriptor) {
buildMethod(descriptors, descriptor);
});
}

/*** Protocols *********************************************************/
Expand All @@ -1815,16 +1829,15 @@ namespace {
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildProtocolList() {
return buildOptionalList(Protocols, Size(0),
chooseNamePrefix("_PROTOCOLS_",
"_CATEGORY_PROTOCOLS_",
"_PROTOCOL_PROTOCOLS_"),
/*isConst*/ true,
[&](ConstantArrayBuilder &descriptors,
ProtocolDecl *protocol) {
buildProtocol(descriptors, protocol);
});
llvm::Constant *buildProtocolList(llvm::GlobalValue::LinkageTypes linkage) {
return buildOptionalList(
Protocols, Size(0),
chooseNamePrefix("_PROTOCOLS_", "_CATEGORY_PROTOCOLS_",
"_PROTOCOL_PROTOCOLS_"),
/*isConst*/ true, linkage,
[&](ConstantArrayBuilder &descriptors, ProtocolDecl *protocol) {
buildProtocol(descriptors, protocol);
});
}

void buildProtocol(ConstantArrayBuilder &array, ProtocolDecl *protocol) {
Expand Down Expand Up @@ -1945,12 +1958,12 @@ namespace {
/// This method does not return a value of a predictable type.
llvm::Constant *buildIvarList() {
Size eltSize = 3 * IGM.getPointerSize() + Size(8);
return buildOptionalList(Ivars, eltSize, "_IVARS_",
/*constant*/ true,
[&](ConstantArrayBuilder &descriptors,
Field field) {
buildIvar(descriptors, field);
});
return buildOptionalList(
Ivars, eltSize, "_IVARS_",
/*constant*/ true, llvm::GlobalVariable::InternalLinkage,
[&](ConstantArrayBuilder &descriptors, Field field) {
buildIvar(descriptors, field);
});
}

/*** Properties ********************************************************/
Expand Down Expand Up @@ -2058,12 +2071,14 @@ namespace {
/// };
///
/// This method does not return a value of a predictable type.
llvm::Constant *buildPropertyList(ForMetaClass_t classOrMeta) {
llvm::Constant *buildPropertyList(ForMetaClass_t classOrMeta,
llvm::GlobalValue::LinkageTypes linkage) {
if (classOrMeta == ForClass) {
return buildPropertyList(InstanceProperties,
chooseNamePrefix("_PROPERTIES_",
"_CATEGORY_PROPERTIES_",
"_PROTOCOL_PROPERTIES_"));
"_PROTOCOL_PROPERTIES_"),
linkage);
}

// Older OSs' libobjcs can't handle class property data.
Expand All @@ -2075,18 +2090,20 @@ namespace {
return buildPropertyList(ClassProperties,
chooseNamePrefix("_CLASS_PROPERTIES_",
"_CATEGORY_CLASS_PROPERTIES_",
"_PROTOCOL_CLASS_PROPERTIES_"));
"_PROTOCOL_CLASS_PROPERTIES_"),
linkage);
}

llvm::Constant *buildPropertyList(ArrayRef<VarDecl*> properties,
StringRef namePrefix) {
llvm::Constant *buildPropertyList(ArrayRef<VarDecl *> properties,
StringRef namePrefix,
llvm::GlobalValue::LinkageTypes linkage) {
Size eltSize = 2 * IGM.getPointerSize();
return buildOptionalList(properties, eltSize, namePrefix,
/*constant*/ true,
[&](ConstantArrayBuilder &descriptors,
VarDecl *property) {
buildProperty(descriptors, property);
});
return buildOptionalList(
properties, eltSize, namePrefix,
/*constant*/ true, linkage,
[&](ConstantArrayBuilder &descriptors, VarDecl *property) {
buildProperty(descriptors, property);
});
}

/*** General ***********************************************************/
Expand All @@ -2098,10 +2115,9 @@ namespace {
/// \param optionalEltSize - if non-zero, a size which needs
/// to be placed in the list header
template <class C, class Fn>
llvm::Constant *buildOptionalList(const C &objects,
Size optionalEltSize,
StringRef nameBase,
bool isConst,
llvm::Constant *buildOptionalList(const C &objects, Size optionalEltSize,
StringRef nameBase, bool isConst,
llvm::GlobalValue::LinkageTypes linkage,
Fn &&buildElement) {
if (objects.empty())
return null();
Expand Down Expand Up @@ -2140,9 +2156,9 @@ namespace {

fields.fillPlaceholderWithInt(countPosition, countType, count);

return buildGlobalVariable(fields, nameBase, isConst);
return buildGlobalVariable(fields, nameBase, isConst, linkage);
}

/// Get the name of the class or protocol to mangle into the ObjC symbol
/// name.
StringRef getEntityName(llvm::SmallVectorImpl<char> &buffer) const {
Expand All @@ -2169,9 +2185,9 @@ namespace {
/// Build a private global variable as a structure containing the
/// given fields.
template <class B>
llvm::Constant *buildGlobalVariable(B &fields, StringRef nameBase, bool isConst,
llvm::GlobalValue::LinkageTypes linkage =
llvm::GlobalVariable::WeakAnyLinkage) {
llvm::Constant *
buildGlobalVariable(B &fields, StringRef nameBase, bool isConst,
llvm::GlobalValue::LinkageTypes linkage) {
llvm::SmallString<64> nameBuffer;
auto var =
fields.finishAndCreateGlobal(Twine(nameBase)
Expand Down
2 changes: 1 addition & 1 deletion test/IRGen/generic_casts.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ import gizmo
// CHECK: @"\01l_OBJC_LABEL_PROTOCOL_$_NSRuncing" = weak hidden global i8* bitcast ({{.*}} @_PROTOCOL_NSRuncing to i8*), section {{"__DATA,__objc_protolist,coalesced,no_dead_strip"|"objc_protolist"|".objc_protolist\$B"}}
// CHECK: @"\01l_OBJC_PROTOCOL_REFERENCE_$_NSRuncing" = weak hidden global i8* bitcast ({{.*}} @_PROTOCOL_NSRuncing to i8*), section {{"__DATA,__objc_protorefs,coalesced,no_dead_strip"|"objc_protorefs"|".objc_protorefs\$B"}}

// CHECK: @_PROTOCOLS__TtC13generic_casts10ObjCClass2 = weak hidden constant { i64, [1 x i8*] } {
// CHECK: @_PROTOCOLS__TtC13generic_casts10ObjCClass2 = internal constant { i64, [1 x i8*] } {
// CHECK: i64 1,
// CHECK: @_PROTOCOL__TtP13generic_casts10ObjCProto2_
// CHECK: }
Expand Down
2 changes: 1 addition & 1 deletion test/IRGen/objc_async_metadata.swift
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Expand Up @@ -12,7 +12,7 @@ import Foundation
// CHECK: [[ENCODE_ASYNC_STRING:@.*]] = private unnamed_addr constant [28 x i8] c"v24@0:8@?<v@?@\22NSString\22>16\00"
// CHECK: [[ENCODE_ASYNC_THROWS_STRING:@.*]] = private unnamed_addr constant [38 x i8] c"v24@0:8@?<v@?@\22NSString\22@\22NSError\22>16\00"

// CHECK: @_INSTANCE_METHODS__TtC19objc_async_metadata7MyClass = weak hidden constant
// CHECK: @_INSTANCE_METHODS__TtC19objc_async_metadata7MyClass = internal constant
// CHECK-SAME: methodWithCompletionHandler:
// CHECK-SAME: [[ENCODE_ASYNC_STRING]]
// CHECK-SAME: throwingMethodWithCompletionHandler:
Expand Down
4 changes: 2 additions & 2 deletions test/IRGen/objc_attr_NSManaged.sil
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Expand Up @@ -17,12 +17,12 @@ import Foundation
sil_vtable X {}

// The getter/setter should not show up in the Objective-C metadata.
// CHECK: @_INSTANCE_METHODS__TtC19objc_attr_NSManaged10SwiftGizmo = weak hidden constant { i32, i32, [2 x { i8*, i8*, i8* }] } { i32 24, i32 2, {{.*}} @"\01L_selector_data(initWithBellsOn:)", {{.*}} @"\01L_selector_data(init)",
// CHECK: @_INSTANCE_METHODS__TtC19objc_attr_NSManaged10SwiftGizmo = internal constant { i32, i32, [2 x { i8*, i8*, i8* }] } { i32 24, i32 2, {{.*}} @"\01L_selector_data(initWithBellsOn:)", {{.*}} @"\01L_selector_data(init)",

// CHECK: [[X:@[0-9]+]] = private unnamed_addr constant [2 x i8] c"x\00"

// The property 'x' should show up in the Objective-C metadata.
// CHECK: @_PROPERTIES__TtC19objc_attr_NSManaged10SwiftGizmo = weak hidden constant { {{.*}}i32, i32, [1 x { i8*, i8* }] } { i32 16, i32 1, [1 x { i8*, i8* }] [{ i8*, i8* } { i8* getelementptr inbounds ([2 x i8], [2 x i8]* [[X]], i64 0, i64 0),
// CHECK: @_PROPERTIES__TtC19objc_attr_NSManaged10SwiftGizmo = internal constant { {{.*}}i32, i32, [1 x { i8*, i8* }] } { i32 16, i32 1, [1 x { i8*, i8* }] [{ i8*, i8* } { i8* getelementptr inbounds ([2 x i8], [2 x i8]* [[X]], i64 0, i64 0),

// The getter/setter should not show up in the Swift metadata.
// CHECK: @"$s19objc_attr_NSManaged10SwiftGizmoCMf" = internal global <{ {{.*}} }> <{ void (%T19objc_attr_NSManaged10SwiftGizmoC*)* {{.*}}@"$s19objc_attr_NSManaged10SwiftGizmoCfD{{(\.ptrauth)?}}"{{.*}}, i8**{{.*}} @"$sBOWV{{(.ptrauth)?(.)?[0-9]?}}"{{.*}}, {{.*}} @"OBJC_METACLASS_$__TtC19objc_attr_NSManaged10SwiftGizmo{{(.ptrauth)?}}"{{.*}}, %objc_class*{{.*}} @"OBJC_CLASS_$_Gizmo{{(.ptrauth)?}}"{{.*}}, %swift.opaque* @_objc_empty_cache, %swift.opaque* null,{{.*}}@_DATA__TtC19objc_attr_NSManaged10SwiftGizmo{{.*}}i64 {{1|2}}){{.*}}, i32 {{1|0}}, i32 0, i32 8, i16 7, i16 0, i32 96, i32 16, {{.*}}* @"$s19objc_attr_NSManaged10SwiftGizmoCMn{{(\.ptrauth)?}}"{{.*}}, i8* null }>
Expand Down
6 changes: 3 additions & 3 deletions test/IRGen/objc_bridge.swift
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Expand Up @@ -11,7 +11,7 @@ import Foundation
// CHECK: [[SETTER_SIGNATURE:@.*]] = private unnamed_addr constant [11 x i8] c"v24@0:8@16\00"
// CHECK: [[DEALLOC_SIGNATURE:@.*]] = private unnamed_addr constant [8 x i8] c"v16@0:8\00"

// CHECK: @_INSTANCE_METHODS__TtC11objc_bridge3Bas = weak hidden constant { i32, i32, [17 x { i8*, i8*, i8* }] } {
// CHECK: @_INSTANCE_METHODS__TtC11objc_bridge3Bas = internal constant { i32, i32, [17 x { i8*, i8*, i8* }] } {
// CHECK: i32 24,
// CHECK: i32 17,
// CHECK: [17 x { i8*, i8*, i8* }] [
Expand Down Expand Up @@ -114,10 +114,10 @@ import Foundation
// CHECK: ]
// CHECK: }, section "__DATA, {{.*}}", align 8

// CHECK: @_PROPERTIES__TtC11objc_bridge3Bas = weak hidden constant { i32, i32, [5 x { i8*, i8* }] } {
// CHECK: @_PROPERTIES__TtC11objc_bridge3Bas = internal constant { i32, i32, [5 x { i8*, i8* }] } {

// CHECK: [[OBJC_BLOCK_PROPERTY:@.*]] = private unnamed_addr constant [8 x i8] c"T@?,N,C\00"
// CHECK: @_PROPERTIES__TtC11objc_bridge21OptionalBlockProperty = weak hidden constant {{.*}} [[OBJC_BLOCK_PROPERTY]]
// CHECK: @_PROPERTIES__TtC11objc_bridge21OptionalBlockProperty = internal constant {{.*}} [[OBJC_BLOCK_PROPERTY]]

func getDescription(_ o: NSObject) -> String {
return o.description
Expand Down
4 changes: 2 additions & 2 deletions test/IRGen/objc_class_property.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -6,10 +6,10 @@
// class properties, so no ObjC property is reflected.

// CHECK-NOT: @_PROPERTIES__TtC19objc_class_property7Smashed
// CHECK: @_CLASS_METHODS__TtC19objc_class_property7Smashed = weak hidden constant { i32, i32, [1 x { i8*, i8*, i8* }] } {
// CHECK: @_CLASS_METHODS__TtC19objc_class_property7Smashed = internal constant { i32, i32, [1 x { i8*, i8*, i8* }] } {
// CHECK: i8* getelementptr inbounds ([14 x i8], [14 x i8]* @"\01L_selector_data(sharedSmashed)"
// CHECK-NOT: @_PROPERTIES__TtC19objc_class_property7Smashed
// CHECK: @_INSTANCE_METHODS__TtC19objc_class_property7Smashed = weak hidden constant { i32, i32, [1 x { i8*, i8*, i8* }] } {
// CHECK: @_INSTANCE_METHODS__TtC19objc_class_property7Smashed = internal constant { i32, i32, [1 x { i8*, i8*, i8* }] } {
// CHECK: i8* getelementptr inbounds ([5 x i8], [5 x i8]* @"\01L_selector_data(init)"
// CHECK-NOT: @_PROPERTIES__TtC19objc_class_property7Smashed

Expand Down
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