[lld-macho] Category Merging: Detect correct class language for classes with aliased symbols #97454
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@llvm/pr-subscribers-lld @llvm/pr-subscribers-lld-macho Author: None (alx32) ChangesCurrently we rely on detecting the source language of a class by the name of the symbol pointing to it. This generally works, but there are scenarios where Swift generates both an ObjC name and a Swift name for the symbol - by aliasing the ObjC name to the Swift name, as follows: So to correctly detect the source language in all cases, we need to handle scenarios where both an ObjC symbol and a Swift symbol is defined for a class - in this case the symbol is always a Swift class. Full diff: https://github.com/llvm/llvm-project/pull/97454.diff 2 Files Affected:
diff --git a/lld/MachO/ObjC.cpp b/lld/MachO/ObjC.cpp
index 413fa0bb64390..da1ec566f799e 100644
--- a/lld/MachO/ObjC.cpp
+++ b/lld/MachO/ObjC.cpp
@@ -495,6 +495,7 @@ class ObjcCategoryMerger {
Defined *tryGetDefinedAtIsecOffset(const ConcatInputSection *isec,
uint32_t offset);
Defined *getClassRo(const Defined *classSym, bool getMetaRo);
+ SourceLanguage getClassSymSourceLang(const Defined *classSym);
void mergeCategoriesIntoBaseClass(const Defined *baseClass,
std::vector<InfoInputCategory> &categories);
void eraseSymbolAtIsecOffset(ConcatInputSection *isec, uint32_t offset);
@@ -1377,6 +1378,29 @@ void objc::mergeCategories() {
void objc::doCleanup() { ObjcCategoryMerger::doCleanup(); }
+ObjcCategoryMerger::SourceLanguage
+ObjcCategoryMerger::getClassSymSourceLang(const Defined *classSym) {
+ if (classSym->getName().starts_with(objc::symbol_names::swift_objc_klass))
+ return SourceLanguage::Swift;
+
+ // If the symbol name matches the ObjC prefix, we don't necessarely know this
+ // comes from ObjC, since Swift creates ObjC-like alias symbols for some Swift
+ // classes. Ex:
+ // .globl _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass
+ // .private_extern _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass
+ // .set _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass, _$s11MyTestClassAACN
+ //
+ // So we scan for symbols with the same address and check for the Swift class
+ if (classSym->getName().starts_with(objc::symbol_names::klass)) {
+ for (auto &sym : classSym->originalIsec->symbols)
+ if (sym->value == classSym->value)
+ if (sym->getName().starts_with(objc::symbol_names::swift_objc_klass))
+ return SourceLanguage::Swift;
+ return SourceLanguage::ObjC;
+ }
+
+ llvm_unreachable("Unexpected class symbol name during category merging");
+}
void ObjcCategoryMerger::mergeCategoriesIntoBaseClass(
const Defined *baseClass, std::vector<InfoInputCategory> &categories) {
assert(categories.size() >= 1 && "Expected at least one category to merge");
@@ -1384,14 +1408,7 @@ void ObjcCategoryMerger::mergeCategoriesIntoBaseClass(
// Collect all the info from the categories
ClassExtensionInfo extInfo(catLayout);
extInfo.baseClass = baseClass;
-
- if (baseClass->getName().starts_with(objc::symbol_names::klass))
- extInfo.baseClassSourceLanguage = SourceLanguage::ObjC;
- else if (baseClass->getName().starts_with(
- objc::symbol_names::swift_objc_klass))
- extInfo.baseClassSourceLanguage = SourceLanguage::Swift;
- else
- llvm_unreachable("Unexpected base class symbol name");
+ extInfo.baseClassSourceLanguage = getClassSymSourceLang(baseClass);
for (auto &catInfo : categories) {
parseCatInfoToExtInfo(catInfo, extInfo);
diff --git a/lld/test/MachO/objc-category-merging-swift-class-ext.s b/lld/test/MachO/objc-category-merging-swift-class-ext.s
new file mode 100644
index 0000000000000..591897172cc87
--- /dev/null
+++ b/lld/test/MachO/objc-category-merging-swift-class-ext.s
@@ -0,0 +1,444 @@
+# REQUIRES: aarch64
+# RUN: rm -rf %t; mkdir %t && cd %t
+
+############ Test merging multiple categories into a single category ############
+## Apply category merging to swiftc code just make sure we can handle addends
+## and don't erase category names for swift -- in order to not crash
+# RUN: llvm-mc -filetype=obj -triple=arm64-apple-macos -o cat_swift.o %s
+# RUN: %lld -arch arm64 -dylib -o cat_swift.dylib cat_swift.o -objc_category_merging
+# RUN: llvm-objdump --objc-meta-data --macho cat_swift.dylib | FileCheck %s --check-prefixes=CHECK-MERGE
+
+
+; CHECK-MERGE: Contents of (__DATA_CONST,__objc_classlist) section
+
+; CHECK-MERGE-NEXT: [[#%x,]] 0x[[#%x,]] _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass
+; CHECK-MERGE-NEXT: isa 0x[[#%x,]] _OBJC_METACLASS_$__TtC11MyTestClass11MyTestClass
+; CHECK-MERGE-NEXT: superclass 0x0
+; CHECK-MERGE-NEXT: cache 0x0
+; CHECK-MERGE-NEXT: vtable 0x0
+; CHECK-MERGE-NEXT: data 0x[[#%x,]] (struct class_ro_t *) Swift class
+; CHECK-MERGE-NEXT: flags 0x80
+; CHECK-MERGE-NEXT: instanceStart 8
+; CHECK-MERGE-NEXT: instanceSize 8
+; CHECK-MERGE-NEXT: reserved 0x0
+; CHECK-MERGE-NEXT: ivarLayout 0x0
+; CHECK-MERGE-NEXT: name 0x[[#%x,]] _TtC11MyTestClass11MyTestClass
+; CHECK-MERGE-NEXT: baseMethods 0x[[#%x,]] (struct method_list_t *)
+; CHECK-MERGE-NEXT: entsize 24
+; CHECK-MERGE-NEXT: count 1
+; CHECK-MERGE-NEXT: name 0x[[#%x,]] init
+; CHECK-MERGE-NEXT: types 0x[[#%x,]] @16@0:8
+; CHECK-MERGE-NEXT: imp _$s11MyTestClassAACABycfcTo
+; CHECK-MERGE-NEXT: baseProtocols 0x0
+; CHECK-MERGE-NEXT: ivars 0x0
+; CHECK-MERGE-NEXT: weakIvarLayout 0x0
+; CHECK-MERGE-NEXT: baseProperties 0x0
+; CHECK-MERGE-NEXT: Meta Class
+; CHECK-MERGE-NEXT: isa 0x0
+; CHECK-MERGE-NEXT: superclass 0x0
+; CHECK-MERGE-NEXT: cache 0x0
+; CHECK-MERGE-NEXT: vtable 0x0
+; CHECK-MERGE-NEXT: data 0x[[#%x,]] (struct class_ro_t *)
+; CHECK-MERGE-NEXT: flags 0x81 RO_META
+; CHECK-MERGE-NEXT: instanceStart 40
+; CHECK-MERGE-NEXT: instanceSize 40
+; CHECK-MERGE-NEXT: reserved 0x0
+; CHECK-MERGE-NEXT: ivarLayout 0x0
+; CHECK-MERGE-NEXT: name 0x[[#%x,]] _TtC11MyTestClass11MyTestClass
+; CHECK-MERGE-NEXT: baseMethods 0x0 (struct method_list_t *)
+; CHECK-MERGE-NEXT: baseProtocols 0x0
+; CHECK-MERGE-NEXT: ivars 0x0
+; CHECK-MERGE-NEXT: weakIvarLayout 0x0
+; CHECK-MERGE-NEXT: baseProperties 0x0
+
+
+; ================== Generated from Swift: ==================
+;; > xcrun swiftc --version
+;; swift-driver version: 1.109.2 Apple Swift version 6.0 (swiftlang-6.0.0.3.300 clang-1600.0.20.10)
+;; > xcrun swiftc -S MyTestClass.swift -o MyTestClass.s
+;;
+; import Foundation
+;
+; protocol MyProtocol {
+; func protocolMethod()
+; }
+;
+; @objc class MyTestClass: NSObject, MyProtocol {
+; func protocolMethod() {
+; }
+; }
+;
+; extension MyTestClass {
+; public func extensionMethod() {
+; }
+; }
+; ================== Generated from Swift: ==================
+
+
+ .section __TEXT,__text,regular,pure_instructions
+ .build_version macos, 11, 0 sdk_version 10, 0
+ .globl _main
+ .p2align 2
+_main:
+ .cfi_startproc
+ mov w0, #0
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAAC14protocolMethodyyF
+ .globl _$s11MyTestClassAAC14protocolMethodyyF
+ .p2align 2
+_$s11MyTestClassAAC14protocolMethodyyF:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAACABycfC
+ .globl _$s11MyTestClassAACABycfC
+ .p2align 2
+_$s11MyTestClassAACABycfC:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAACABycfc
+ .globl _$s11MyTestClassAACABycfc
+ .p2align 2
+_$s11MyTestClassAACABycfc:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAACMa
+ .globl _$s11MyTestClassAACMa
+ .p2align 2
+_$s11MyTestClassAACMa:
+ ret
+
+ .p2align 2
+_$s11MyTestClassAACABycfcTo:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAACfD
+ .globl _$s11MyTestClassAACfD
+ .p2align 2
+_$s11MyTestClassAACfD:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .p2align 2
+_$s11MyTestClassAACAA0A8ProtocolA2aCP14protocolMethodyyFTW:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .private_extern _$s11MyTestClassAAC15extensionMethodyyF
+ .globl _$s11MyTestClassAAC15extensionMethodyyF
+ .p2align 2
+_$s11MyTestClassAAC15extensionMethodyyF:
+ .cfi_startproc
+ ret
+ .cfi_endproc
+
+ .section __TEXT,__objc_methname,cstring_literals
+"L_selector_data(init)":
+ .asciz "init"
+
+ .section __DATA,__objc_selrefs,literal_pointers,no_dead_strip
+ .p2align 3, 0x0
+"L_selector(init)":
+ .quad "L_selector_data(init)"
+
+ .section __TEXT,__objc_methname,cstring_literals
+"L_selector_data(dealloc)":
+ .asciz "dealloc"
+
+ .section __DATA,__objc_selrefs,literal_pointers,no_dead_strip
+ .p2align 3, 0x0
+"L_selector(dealloc)":
+ .quad "L_selector_data(dealloc)"
+
+ .private_extern _$s11MyTestClassAACAA0A8ProtocolAAMc
+ .section __TEXT,__const
+ .globl _$s11MyTestClassAACAA0A8ProtocolAAMc
+ .p2align 2, 0x0
+_$s11MyTestClassAACAA0A8ProtocolAAMc:
+ .long _$s11MyTestClass0A8ProtocolMp-_$s11MyTestClassAACAA0A8ProtocolAAMc
+ .long (_$s11MyTestClassAACMn-_$s11MyTestClassAACAA0A8ProtocolAAMc)-4
+ .long (_$s11MyTestClassAACAA0A8ProtocolAAWP-_$s11MyTestClassAACAA0A8ProtocolAAMc)-8
+ .long 0
+
+ .private_extern _$s11MyTestClassAACAA0A8ProtocolAAWP
+ .section __DATA,__const
+ .globl _$s11MyTestClassAACAA0A8ProtocolAAWP
+ .p2align 3, 0x0
+_$s11MyTestClassAACAA0A8ProtocolAAWP:
+ .quad _$s11MyTestClassAACAA0A8ProtocolAAMc
+ .quad _$s11MyTestClassAACAA0A8ProtocolA2aCP14protocolMethodyyFTW
+
+ .section __TEXT,__swift5_entry,regular,no_dead_strip
+ .p2align 2, 0x0
+l_entry_point:
+ .long _main-l_entry_point
+ .long 0
+
+ .private_extern "_symbolic $s11MyTestClass0A8ProtocolP"
+ .section __TEXT,__swift5_typeref
+ .globl "_symbolic $s11MyTestClass0A8ProtocolP"
+ .weak_definition "_symbolic $s11MyTestClass0A8ProtocolP"
+ .p2align 1, 0x0
+"_symbolic $s11MyTestClass0A8ProtocolP":
+ .ascii "$s11MyTestClass0A8ProtocolP"
+ .byte 0
+
+ .section __TEXT,__swift5_fieldmd
+ .p2align 2, 0x0
+_$s11MyTestClass0A8Protocol_pMF:
+ .long "_symbolic $s11MyTestClass0A8ProtocolP"-_$s11MyTestClass0A8Protocol_pMF
+ .long 0
+ .short 4
+ .short 12
+ .long 0
+
+ .section __TEXT,__const
+l_.str.11.MyTestClass:
+ .asciz "MyTestClass"
+
+ .private_extern _$s11MyTestClassMXM
+ .section __TEXT,__constg_swiftt
+ .globl _$s11MyTestClassMXM
+ .weak_definition _$s11MyTestClassMXM
+ .p2align 2, 0x0
+_$s11MyTestClassMXM:
+ .long 0
+ .long 0
+ .long (l_.str.11.MyTestClass-_$s11MyTestClassMXM)-8
+
+ .section __TEXT,__const
+l_.str.10.MyProtocol:
+ .asciz "MyProtocol"
+
+ .private_extern _$s11MyTestClass0A8ProtocolMp
+ .section __TEXT,__constg_swiftt
+ .globl _$s11MyTestClass0A8ProtocolMp
+ .p2align 2, 0x0
+_$s11MyTestClass0A8ProtocolMp:
+ .long 65603
+ .long (_$s11MyTestClassMXM-_$s11MyTestClass0A8ProtocolMp)-4
+ .long (l_.str.10.MyProtocol-_$s11MyTestClass0A8ProtocolMp)-8
+ .long 0
+ .long 1
+ .long 0
+ .long 17
+ .long 0
+
+ .private_extern _OBJC_METACLASS_$__TtC11MyTestClass11MyTestClass
+ .section __DATA,__data
+ .globl _OBJC_METACLASS_$__TtC11MyTestClass11MyTestClass
+ .p2align 3, 0x0
+_OBJC_METACLASS_$__TtC11MyTestClass11MyTestClass:
+ .quad _OBJC_METACLASS_$_NSObject
+ .quad _OBJC_METACLASS_$_NSObject
+ .quad __objc_empty_cache
+ .quad 0
+ .quad __METACLASS_DATA__TtC11MyTestClass11MyTestClass
+
+ .section __TEXT,__cstring,cstring_literals
+ .p2align 4, 0x0
+l_.str.30._TtC11MyTestClass11MyTestClass:
+ .asciz "_TtC11MyTestClass11MyTestClass"
+
+ .section __DATA,__objc_const
+ .p2align 3, 0x0
+__METACLASS_DATA__TtC11MyTestClass11MyTestClass:
+ .long 129
+ .long 40
+ .long 40
+ .long 0
+ .quad 0
+ .quad l_.str.30._TtC11MyTestClass11MyTestClass
+ .quad 0
+ .quad 0
+ .quad 0
+ .quad 0
+ .quad 0
+
+ .section __TEXT,__cstring,cstring_literals
+"l_.str.7.@16@0:8":
+ .asciz "@16@0:8"
+
+ .section __DATA,__objc_data
+ .p2align 3, 0x0
+__INSTANCE_METHODS__TtC11MyTestClass11MyTestClass:
+ .long 24
+ .long 1
+ .quad "L_selector_data(init)"
+ .quad "l_.str.7.@16@0:8"
+ .quad _$s11MyTestClassAACABycfcTo
+
+ .p2align 3, 0x0
+__DATA__TtC11MyTestClass11MyTestClass:
+ .long 128
+ .long 8
+ .long 8
+ .long 0
+ .quad 0
+ .quad l_.str.30._TtC11MyTestClass11MyTestClass
+ .quad __INSTANCE_METHODS__TtC11MyTestClass11MyTestClass
+ .quad 0
+ .quad 0
+ .quad 0
+ .quad 0
+
+ .private_extern "_symbolic So8NSObjectC"
+ .section __TEXT,__swift5_typeref
+ .globl "_symbolic So8NSObjectC"
+ .weak_definition "_symbolic So8NSObjectC"
+ .p2align 1, 0x0
+"_symbolic So8NSObjectC":
+ .ascii "So8NSObjectC"
+ .byte 0
+
+ .private_extern _$s11MyTestClassAACMn
+ .section __TEXT,__constg_swiftt
+ .globl _$s11MyTestClassAACMn
+ .p2align 2, 0x0
+_$s11MyTestClassAACMn:
+ .long 2147483728
+ .long (_$s11MyTestClassMXM-_$s11MyTestClassAACMn)-4
+ .long (l_.str.11.MyTestClass-_$s11MyTestClassAACMn)-8
+ .long (_$s11MyTestClassAACMa-_$s11MyTestClassAACMn)-12
+ .long (_$s11MyTestClassAACMF-_$s11MyTestClassAACMn)-16
+ .long ("_symbolic So8NSObjectC"-_$s11MyTestClassAACMn)-20
+ .long 3
+ .long 11
+ .long 1
+ .long 0
+ .long 10
+ .long 10
+ .long 1
+ .long 16
+ .long (_$s11MyTestClassAAC14protocolMethodyyF-_$s11MyTestClassAACMn)-56
+
+ .section __DATA,__objc_data
+ .p2align 3, 0x0
+_$s11MyTestClassAACMf:
+ .quad 0
+ .quad _$s11MyTestClassAACfD
+ .quad _$sBOWV
+ .quad _OBJC_METACLASS_$__TtC11MyTestClass11MyTestClass
+ .quad _OBJC_CLASS_$_NSObject
+ .quad __objc_empty_cache
+ .quad 0
+ .quad __DATA__TtC11MyTestClass11MyTestClass+2
+ .long 0
+ .long 0
+ .long 8
+ .short 7
+ .short 0
+ .long 112
+ .long 24
+ .quad _$s11MyTestClassAACMn
+ .quad 0
+ .quad _$s11MyTestClassAAC14protocolMethodyyF
+
+ .private_extern "_symbolic _____ 11MyTestClassAAC"
+ .section __TEXT,__swift5_typeref
+ .globl "_symbolic _____ 11MyTestClassAAC"
+ .weak_definition "_symbolic _____ 11MyTestClassAAC"
+ .p2align 1, 0x0
+"_symbolic _____ 11MyTestClassAAC":
+ .byte 1
+ .long (_$s11MyTestClassAACMn-"_symbolic _____ 11MyTestClassAAC")-1
+ .byte 0
+
+ .section __TEXT,__swift5_fieldmd
+ .p2align 2, 0x0
+_$s11MyTestClassAACMF:
+ .long "_symbolic _____ 11MyTestClassAAC"-_$s11MyTestClassAACMF
+ .long ("_symbolic So8NSObjectC"-_$s11MyTestClassAACMF)-4
+ .short 7
+ .short 12
+ .long 0
+
+ .section __TEXT,__swift5_protos
+ .p2align 2, 0x0
+l_$s11MyTestClass0A8ProtocolHr:
+ .long _$s11MyTestClass0A8ProtocolMp-l_$s11MyTestClass0A8ProtocolHr
+
+ .section __TEXT,__swift5_proto
+ .p2align 2, 0x0
+l_$s11MyTestClassAACAA0A8ProtocolAAHc:
+ .long _$s11MyTestClassAACAA0A8ProtocolAAMc-l_$s11MyTestClassAACAA0A8ProtocolAAHc
+
+ .section __TEXT,__swift5_types
+ .p2align 2, 0x0
+l_$s11MyTestClassAACHn:
+ .long _$s11MyTestClassAACMn-l_$s11MyTestClassAACHn
+
+ .private_extern ___swift_reflection_version
+ .section __TEXT,__const
+ .globl ___swift_reflection_version
+ .weak_definition ___swift_reflection_version
+ .p2align 1, 0x0
+___swift_reflection_version:
+ .short 3
+
+ .section __DATA,__objc_classlist,regular,no_dead_strip
+ .p2align 3, 0x0
+_objc_classes_$s11MyTestClassAACN:
+ .quad _$s11MyTestClassAACN
+
+ .no_dead_strip _main
+ .no_dead_strip l_entry_point
+ .no_dead_strip _$s11MyTestClass0A8Protocol_pMF
+ .no_dead_strip _$s11MyTestClassAACMF
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftFoundation_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftDarwin_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftObjectiveC_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftCoreFoundation_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftDispatch_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftXPC_$_MyTestClass
+ .no_dead_strip __swift_FORCE_LOAD_$_swiftIOKit_$_MyTestClass
+ .no_dead_strip l_$s11MyTestClass0A8ProtocolHr
+ .no_dead_strip l_$s11MyTestClassAACAA0A8ProtocolAAHc
+ .no_dead_strip l_$s11MyTestClassAACHn
+ .no_dead_strip ___swift_reflection_version
+ .no_dead_strip _objc_classes_$s11MyTestClassAACN
+ .section __DATA,__objc_imageinfo,regular,no_dead_strip
+L_OBJC_IMAGE_INFO:
+ .long 0
+ .long 100665152
+
+ .globl _$s11MyTestClass0A8ProtocolTL
+ .private_extern _$s11MyTestClass0A8ProtocolTL
+ .alt_entry _$s11MyTestClass0A8ProtocolTL
+.set _$s11MyTestClass0A8ProtocolTL, (_$s11MyTestClass0A8ProtocolMp+24)-8
+ .globl _$s11MyTestClassAAC14protocolMethodyyFTq
+ .private_extern _$s11MyTestClassAAC14protocolMethodyyFTq
+ .alt_entry _$s11MyTestClassAAC14protocolMethodyyFTq
+.set _$s11MyTestClassAAC14protocolMethodyyFTq, _$s11MyTestClassAACMn+52
+ .globl _$s11MyTestClassAACN
+ .private_extern _$s11MyTestClassAACN
+ .alt_entry _$s11MyTestClassAACN
+.set _$s11MyTestClassAACN, _$s11MyTestClassAACMf+24
+ .globl _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass
+ .private_extern _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass
+.set _OBJC_CLASS_$__TtC11MyTestClass11MyTestClass, _$s11MyTestClassAACN
+ .weak_reference __swift_FORCE_LOAD_$_swiftFoundation
+ .weak_reference __swift_FORCE_LOAD_$_swiftDarwin
+ .weak_reference __swift_FORCE_LOAD_$_swiftObjectiveC
+ .weak_reference __swift_FORCE_LOAD_$_swiftCoreFoundation
+ .weak_reference __swift_FORCE_LOAD_$_swiftDispatch
+ .weak_reference __swift_FORCE_LOAD_$_swiftXPC
+ .weak_reference __swift_FORCE_LOAD_$_swiftIOKit
+.subsections_via_symbols
+
+_OBJC_CLASS_$_NSObject:
+_OBJC_METACLASS_$_NSObject:
+__objc_empty_cache:
+_$sBOWV:
+ .quad 0
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Currently we rely on detecting the source language of a class by the name of the symbol pointing to it. This generally works, but there are scenarios where Swift generates both an ObjC name and a Swift name for the symbol - by aliasing the ObjC name to the Swift name, as follows:
So to correctly detect the source language in all cases, we need to handle scenarios where both an ObjC symbol and a Swift symbol is defined for a class - in this case the symbol is always a Swift class.