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alx32yuxuanchen1997
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yuxuanchen1997
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[lld-macho] Fix erasing category names for ObjC categories (#99400)
Summary: We were already not deleting category names for Swift classes as those names can be reused by other parts. However, I have come across a corner case where this also happens for ObjC categories - so we can't delete category names for them either. TODO remains to optimize this behavior for both ObjC and Swift. Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60251277
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‎lld/MachO/ObjC.cpp

Lines changed: 9 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1303,12 +1303,16 @@ void ObjcCategoryMerger::eraseMergedCategories() {
13031303
continue;
13041304

13051305
eraseISec(catInfo.catBodyIsec);
1306-
// We can't erase 'catLayout.nameOffset' for Swift categories because the
1307-
// name will be referenced for generating relative offsets
1308-
// See usages of 'l_.str.11.SimpleClass' in objc-category-merging-swift.s
1306+
1307+
// We can't erase 'catLayout.nameOffset' for either Swift or ObjC
1308+
// categories because the name will sometimes also be used for other
1309+
// purposes.
1310+
// For Swift, see usages of 'l_.str.11.SimpleClass' in
1311+
// objc-category-merging-swift.s
1312+
// For ObjC, see usages of 'l_OBJC_CLASS_NAME_.1' in
1313+
// objc-category-merging-erase-objc-name-test.s
13091314
// TODO: handle the above in a smarter way
1310-
if (catInfo.sourceLanguage != SourceLanguage::Swift)
1311-
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec, catLayout.nameOffset);
1315+
13121316
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,
13131317
catLayout.instanceMethodsOffset);
13141318
tryEraseDefinedAtIsecOffset(catInfo.catBodyIsec,

‎lld/test/MachO/objc-category-merging-erase-objc-name-test.s

Lines changed: 306 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,306 @@
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; REQUIRES: aarch64
2+
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; Here we test that if we defined a protocol MyTestProtocol and also a category MyTestProtocol
4+
; then when merging the category into the base class (and deleting the category), we don't
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; delete the 'MyTestProtocol' name
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; RUN: llvm-mc -filetype=obj -triple=arm64-apple-macos -o erase-objc-name.o %s
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; RUN: %lld -arch arm64 -dylib -o erase-objc-name.dylib erase-objc-name.o -objc_category_merging
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; RUN: llvm-objdump --objc-meta-data --macho erase-objc-name.dylib | FileCheck %s --check-prefixes=MERGE_CATS
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; === Check merge categories enabled ===
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; Check that the original categories are not there
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; MERGE_CATS-NOT: __OBJC_$_CATEGORY_MyBaseClass_$_Category01
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; MERGE_CATS-NOT: __OBJC_$_CATEGORY_MyBaseClass_$_Category02
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; Check that we get the expected output - most importantly that the protocol is named `MyTestProtocol`
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; MERGE_CATS: Contents of (__DATA_CONST,__objc_classlist) section
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; MERGE_CATS-NEXT: _OBJC_CLASS_$_MyBaseClass
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; MERGE_CATS-NEXT: isa {{.*}} _OBJC_METACLASS_$_MyBaseClass
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; MERGE_CATS-NEXT: superclass {{.*}}
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; MERGE_CATS-NEXT: cache {{.*}}
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; MERGE_CATS-NEXT: vtable {{.*}}
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; MERGE_CATS-NEXT: data {{.*}} (struct class_ro_t *)
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; MERGE_CATS-NEXT: flags {{.*}} RO_ROOT
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; MERGE_CATS-NEXT: instanceStart 0
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; MERGE_CATS-NEXT: instanceSize 0
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; MERGE_CATS-NEXT: reserved {{.*}}
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; MERGE_CATS-NEXT: ivarLayout {{.*}}
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; MERGE_CATS-NEXT: name {{.*}} MyBaseClass
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; MERGE_CATS-NEXT: baseMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: entsize 24
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; MERGE_CATS-NEXT: count 2
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; MERGE_CATS-NEXT: name {{.*}} getValue
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; MERGE_CATS-NEXT: types {{.*}} i16@0:8
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; MERGE_CATS-NEXT: imp -[MyBaseClass(MyTestProtocol) getValue]
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; MERGE_CATS-NEXT: name {{.*}} baseInstanceMethod
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; MERGE_CATS-NEXT: types {{.*}} v16@0:8
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; MERGE_CATS-NEXT: imp -[MyBaseClass baseInstanceMethod]
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; MERGE_CATS-NEXT: baseProtocols {{.*}}
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; MERGE_CATS-NEXT: count 1
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; MERGE_CATS-NEXT: list[0] {{.*}} (struct protocol_t *)
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; MERGE_CATS-NEXT: isa {{.*}}
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; MERGE_CATS-NEXT: name {{.*}} MyTestProtocol
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; MERGE_CATS-NEXT: protocols {{.*}}
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; MERGE_CATS-NEXT: instanceMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: entsize 24
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; MERGE_CATS-NEXT: count 1
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; MERGE_CATS-NEXT: name {{.*}} getValue
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; MERGE_CATS-NEXT: types {{.*}} i16@0:8
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; MERGE_CATS-NEXT: imp {{.*}}
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; MERGE_CATS-NEXT: classMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: optionalInstanceMethods {{.*}}
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; MERGE_CATS-NEXT: optionalClassMethods {{.*}}
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; MERGE_CATS-NEXT: instanceProperties {{.*}}
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; MERGE_CATS-NEXT: ivars {{.*}}
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; MERGE_CATS-NEXT: weakIvarLayout {{.*}}
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; MERGE_CATS-NEXT: baseProperties {{.*}}
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; MERGE_CATS-NEXT: Meta Class
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; MERGE_CATS-NEXT: isa {{.*}} _OBJC_METACLASS_$_MyBaseClass
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; MERGE_CATS-NEXT: superclass {{.*}} _OBJC_CLASS_$_MyBaseClass
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; MERGE_CATS-NEXT: cache {{.*}}
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; MERGE_CATS-NEXT: vtable {{.*}}
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; MERGE_CATS-NEXT: data {{.*}} (struct class_ro_t *)
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; MERGE_CATS-NEXT: flags {{.*}} RO_META RO_ROOT
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; MERGE_CATS-NEXT: instanceStart 40
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; MERGE_CATS-NEXT: instanceSize 40
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; MERGE_CATS-NEXT: reserved {{.*}}
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; MERGE_CATS-NEXT: ivarLayout {{.*}}
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; MERGE_CATS-NEXT: name {{.*}} MyBaseClass
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; MERGE_CATS-NEXT: baseMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: baseProtocols {{.*}}
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; MERGE_CATS-NEXT: count 1
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; MERGE_CATS-NEXT: list[0] {{.*}} (struct protocol_t *)
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; MERGE_CATS-NEXT: isa {{.*}}
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; MERGE_CATS-NEXT: name {{.*}} MyTestProtocol
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; MERGE_CATS-NEXT: protocols {{.*}}
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; MERGE_CATS-NEXT: instanceMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: entsize 24
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; MERGE_CATS-NEXT: count 1
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; MERGE_CATS-NEXT: name {{.*}} getValue
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; MERGE_CATS-NEXT: types {{.*}} i16@0:8
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; MERGE_CATS-NEXT: imp {{.*}}
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; MERGE_CATS-NEXT: classMethods {{.*}} (struct method_list_t *)
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; MERGE_CATS-NEXT: optionalInstanceMethods {{.*}}
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; MERGE_CATS-NEXT: optionalClassMethods {{.*}}
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; MERGE_CATS-NEXT: instanceProperties {{.*}}
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; MERGE_CATS-NEXT: ivars {{.*}}
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; MERGE_CATS-NEXT: weakIvarLayout {{.*}}
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; MERGE_CATS-NEXT: baseProperties {{.*}}
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; MERGE_CATS-NEXT: Contents of (__DATA_CONST,__objc_protolist) section
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; MERGE_CATS-NEXT: {{.*}} {{.*}} __OBJC_PROTOCOL_$_MyTestProtocol
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; MERGE_CATS-NEXT: Contents of (__DATA_CONST,__objc_imageinfo) section
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; MERGE_CATS-NEXT: version 0
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; MERGE_CATS-NEXT: flags {{.*}} OBJC_IMAGE_HAS_CATEGORY_CLASS_PROPERTIES
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; ================== repro.sh ====================
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; # Write the Objective-C code to a file
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; cat << EOF > MyClass.m
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; @protocol MyTestProtocol
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; - (int)getValue;
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; @end
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;
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; __attribute__((objc_root_class))
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; @interface MyBaseClass
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; - (void)baseInstanceMethod;
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; @end
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;
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; @implementation MyBaseClass
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; - (void)baseInstanceMethod {}
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; @end
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;
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; @interface MyBaseClass (MyTestProtocol) <MyTestProtocol>
114+
; @end
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;
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; @implementation MyBaseClass (MyTestProtocol)
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;
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; - (int)getValue {
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; return 0x30;
120+
; }
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;
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; @end
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; EOF
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;
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; # Compile the Objective-C file to assembly
126+
; xcrun clang -S -arch arm64 MyClass.m -o MyClass.s
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; ==============================================
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129+
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.section __TEXT,__text,regular,pure_instructions
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.p2align 2 ; -- Begin function -[MyBaseClass baseInstanceMethod]
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"-[MyBaseClass baseInstanceMethod]": ; @"\01-[MyBaseClass baseInstanceMethod]"
133+
.cfi_startproc
134+
; %bb.0:
135+
sub sp, sp, #16
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.cfi_def_cfa_offset 16
137+
str x0, [sp, #8]
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str x1, [sp]
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add sp, sp, #16
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ret
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.cfi_endproc
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; -- End function
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.p2align 2 ; -- Begin function -[MyBaseClass(MyTestProtocol) getValue]
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"-[MyBaseClass(MyTestProtocol) getValue]": ; @"\01-[MyBaseClass(MyTestProtocol) getValue]"
145+
.cfi_startproc
146+
; %bb.0:
147+
sub sp, sp, #16
148+
.cfi_def_cfa_offset 16
149+
str x0, [sp, #8]
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str x1, [sp]
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mov w0, #48 ; =0x30
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add sp, sp, #16
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ret
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.cfi_endproc
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; -- End function
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.section __DATA,__objc_data
157+
.globl _OBJC_CLASS_$_MyBaseClass ; @"OBJC_CLASS_$_MyBaseClass"
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.p2align 3, 0x0
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_OBJC_CLASS_$_MyBaseClass:
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.quad _OBJC_METACLASS_$_MyBaseClass
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.quad 0
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.quad __objc_empty_cache
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.quad 0
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.quad __OBJC_CLASS_RO_$_MyBaseClass
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.globl _OBJC_METACLASS_$_MyBaseClass ; @"OBJC_METACLASS_$_MyBaseClass"
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.p2align 3, 0x0
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_OBJC_METACLASS_$_MyBaseClass:
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.quad _OBJC_METACLASS_$_MyBaseClass
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.quad _OBJC_CLASS_$_MyBaseClass
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.quad __objc_empty_cache
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.quad 0
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.quad __OBJC_METACLASS_RO_$_MyBaseClass
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.section __TEXT,__objc_classname,cstring_literals
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l_OBJC_CLASS_NAME_: ; @OBJC_CLASS_NAME_
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.asciz "MyBaseClass"
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.section __DATA,__objc_const
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.p2align 3, 0x0 ; @"_OBJC_METACLASS_RO_$_MyBaseClass"
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__OBJC_METACLASS_RO_$_MyBaseClass:
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.long 131 ; 0x83
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.long 40 ; 0x28
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.long 40 ; 0x28
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.space 4
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.quad 0
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.quad l_OBJC_CLASS_NAME_
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.quad 0
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.quad 0
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.quad 0
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.quad 0
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.quad 0
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.section __TEXT,__objc_methname,cstring_literals
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l_OBJC_METH_VAR_NAME_: ; @OBJC_METH_VAR_NAME_
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.asciz "baseInstanceMethod"
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.section __TEXT,__objc_methtype,cstring_literals
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l_OBJC_METH_VAR_TYPE_: ; @OBJC_METH_VAR_TYPE_
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.asciz "v16@0:8"
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.section __DATA,__objc_const
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.p2align 3, 0x0 ; @"_OBJC_$_INSTANCE_METHODS_MyBaseClass"
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__OBJC_$_INSTANCE_METHODS_MyBaseClass:
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.long 24 ; 0x18
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.long 1 ; 0x1
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.quad l_OBJC_METH_VAR_NAME_
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.quad l_OBJC_METH_VAR_TYPE_
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.quad "-[MyBaseClass baseInstanceMethod]"
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.p2align 3, 0x0 ; @"_OBJC_CLASS_RO_$_MyBaseClass"
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__OBJC_CLASS_RO_$_MyBaseClass:
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.long 130 ; 0x82
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.long 0 ; 0x0
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.long 0 ; 0x0
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.space 4
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.quad 0
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.quad l_OBJC_CLASS_NAME_
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.quad __OBJC_$_INSTANCE_METHODS_MyBaseClass
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.quad 0
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.quad 0
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.quad 0
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.quad 0
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.section __TEXT,__objc_classname,cstring_literals
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l_OBJC_CLASS_NAME_.1: ; @OBJC_CLASS_NAME_.1
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.asciz "MyTestProtocol"
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.section __TEXT,__objc_methname,cstring_literals
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l_OBJC_METH_VAR_NAME_.2: ; @OBJC_METH_VAR_NAME_.2
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.asciz "getValue"
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.section __TEXT,__objc_methtype,cstring_literals
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l_OBJC_METH_VAR_TYPE_.3: ; @OBJC_METH_VAR_TYPE_.3
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.asciz "i16@0:8"
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.section __DATA,__objc_const
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.p2align 3, 0x0 ; @"_OBJC_$_CATEGORY_INSTANCE_METHODS_MyBaseClass_$_MyTestProtocol"
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__OBJC_$_CATEGORY_INSTANCE_METHODS_MyBaseClass_$_MyTestProtocol:
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.long 24 ; 0x18
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.long 1 ; 0x1
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.quad l_OBJC_METH_VAR_NAME_.2
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.quad l_OBJC_METH_VAR_TYPE_.3
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.quad "-[MyBaseClass(MyTestProtocol) getValue]"
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.p2align 3, 0x0 ; @"_OBJC_$_PROTOCOL_INSTANCE_METHODS_MyTestProtocol"
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__OBJC_$_PROTOCOL_INSTANCE_METHODS_MyTestProtocol:
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.long 24 ; 0x18
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.long 1 ; 0x1
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.quad l_OBJC_METH_VAR_NAME_.2
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.quad l_OBJC_METH_VAR_TYPE_.3
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.quad 0
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.p2align 3, 0x0 ; @"_OBJC_$_PROTOCOL_METHOD_TYPES_MyTestProtocol"
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__OBJC_$_PROTOCOL_METHOD_TYPES_MyTestProtocol:
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.quad l_OBJC_METH_VAR_TYPE_.3
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.private_extern __OBJC_PROTOCOL_$_MyTestProtocol ; @"_OBJC_PROTOCOL_$_MyTestProtocol"
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.section __DATA,__data
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.globl __OBJC_PROTOCOL_$_MyTestProtocol
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.weak_definition __OBJC_PROTOCOL_$_MyTestProtocol
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.p2align 3, 0x0
249+
__OBJC_PROTOCOL_$_MyTestProtocol:
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.quad 0
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.quad l_OBJC_CLASS_NAME_.1
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.quad 0
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.quad __OBJC_$_PROTOCOL_INSTANCE_METHODS_MyTestProtocol
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.quad 0
255+
.quad 0
256+
.quad 0
257+
.quad 0
258+
.long 96 ; 0x60
259+
.long 0 ; 0x0
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.quad __OBJC_$_PROTOCOL_METHOD_TYPES_MyTestProtocol
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.quad 0
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.quad 0
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.private_extern __OBJC_LABEL_PROTOCOL_$_MyTestProtocol ; @"_OBJC_LABEL_PROTOCOL_$_MyTestProtocol"
264+
.section __DATA,__objc_protolist,coalesced,no_dead_strip
265+
.globl __OBJC_LABEL_PROTOCOL_$_MyTestProtocol
266+
.weak_definition __OBJC_LABEL_PROTOCOL_$_MyTestProtocol
267+
.p2align 3, 0x0
268+
__OBJC_LABEL_PROTOCOL_$_MyTestProtocol:
269+
.quad __OBJC_PROTOCOL_$_MyTestProtocol
270+
.section __DATA,__objc_const
271+
.p2align 3, 0x0 ; @"_OBJC_CATEGORY_PROTOCOLS_$_MyBaseClass_$_MyTestProtocol"
272+
__OBJC_CATEGORY_PROTOCOLS_$_MyBaseClass_$_MyTestProtocol:
273+
.quad 1 ; 0x1
274+
.quad __OBJC_PROTOCOL_$_MyTestProtocol
275+
.quad 0
276+
.p2align 3, 0x0 ; @"_OBJC_$_CATEGORY_MyBaseClass_$_MyTestProtocol"
277+
__OBJC_$_CATEGORY_MyBaseClass_$_MyTestProtocol:
278+
.quad l_OBJC_CLASS_NAME_.1
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.quad _OBJC_CLASS_$_MyBaseClass
280+
.quad __OBJC_$_CATEGORY_INSTANCE_METHODS_MyBaseClass_$_MyTestProtocol
281+
.quad 0
282+
.quad __OBJC_CATEGORY_PROTOCOLS_$_MyBaseClass_$_MyTestProtocol
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.quad 0
284+
.quad 0
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.long 64 ; 0x40
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.space 4
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.section __DATA,__objc_classlist,regular,no_dead_strip
288+
.p2align 3, 0x0 ; @"OBJC_LABEL_CLASS_$"
289+
l_OBJC_LABEL_CLASS_$:
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.quad _OBJC_CLASS_$_MyBaseClass
291+
.section __DATA,__objc_catlist,regular,no_dead_strip
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.p2align 3, 0x0 ; @"OBJC_LABEL_CATEGORY_$"
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l_OBJC_LABEL_CATEGORY_$:
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.quad __OBJC_$_CATEGORY_MyBaseClass_$_MyTestProtocol
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.no_dead_strip __OBJC_PROTOCOL_$_MyTestProtocol
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.no_dead_strip __OBJC_LABEL_PROTOCOL_$_MyTestProtocol
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.section __DATA,__objc_imageinfo,regular,no_dead_strip
298+
L_OBJC_IMAGE_INFO:
299+
.long 0
300+
.long 64
301+
302+
__objc_empty_cache:
303+
_$sBOWV:
304+
.quad 0
305+
306+
.subsections_via_symbols

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