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[objcopy] Implement --weaken, --weaken-symbol(s) flags for Mach-O Object Files (llvm#70560)
This PR implements --weaken, --weaken-symbol(s) flags in llvm-objcopy for Mach-O. Test plan: ninja check-all
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4 files changed

+199
-2
lines changed

4 files changed

+199
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lines changed

‎llvm/lib/ObjCopy/ConfigManager.cpp

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -34,13 +34,13 @@ Expected<const MachOConfig &> ConfigManager::getMachOConfig() const {
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if (!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
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!Common.AllocSectionsPrefix.empty() || !Common.KeepSection.empty() ||
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!Common.SymbolsToGlobalize.empty() || !Common.SymbolsToKeep.empty() ||
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!Common.SymbolsToLocalize.empty() || !Common.SymbolsToWeaken.empty() ||
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!Common.SymbolsToLocalize.empty() ||
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!Common.SymbolsToKeepGlobal.empty() || !Common.SectionsToRename.empty() ||
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!Common.UnneededSymbolsToRemove.empty() ||
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!Common.SetSectionAlignment.empty() || !Common.SetSectionFlags.empty() ||
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!Common.SetSectionType.empty() || Common.ExtractDWO ||
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Common.PreserveDates || Common.StripAllGNU || Common.StripDWO ||
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Common.StripNonAlloc || Common.StripSections || Common.Weaken ||
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Common.StripNonAlloc || Common.StripSections ||
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Common.DecompressDebugSections || Common.StripUnneeded ||
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Common.DiscardMode == DiscardType::Locals || !Common.SymbolsToAdd.empty())
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return createStringError(llvm::errc::invalid_argument,

‎llvm/lib/ObjCopy/MachO/MachOObjcopy.cpp

Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -94,6 +94,14 @@ static void updateAndRemoveSymbols(const CommonConfig &Config,
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const MachOConfig &MachOConfig,
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Object &Obj) {
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for (SymbolEntry &Sym : Obj.SymTable) {
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// Weaken symbols first to match ELFObjcopy behavior.
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bool IsExportedAndDefined =
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(Sym.n_type & llvm::MachO::N_EXT) &&
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(Sym.n_type & llvm::MachO::N_TYPE) != llvm::MachO::N_UNDF;
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if (IsExportedAndDefined &&
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(Config.Weaken || Config.SymbolsToWeaken.matches(Sym.Name)))
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Sym.n_desc |= llvm::MachO::N_WEAK_DEF;
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auto I = Config.SymbolsToRename.find(Sym.Name);
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if (I != Config.SymbolsToRename.end())
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Sym.Name = std::string(I->getValue());

‎llvm/test/tools/llvm-objcopy/MachO/weaken-all.s

Lines changed: 100 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,100 @@
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# REQUIRES: x86-registered-target
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos %s -o %t
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# RUN: llvm-objcopy --weaken %t %t2
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# RUN: llvm-readobj --symbols %t2 --sort-symbols=name | FileCheck %s
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# CHECK: Symbols [
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _global ({{[0-9]+}})
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# CHECK-NEXT: Extern
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __text (0x1)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x80)
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# CHECK-NEXT: WeakDef (0x80)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _global_data ({{[0-9]+}})
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# CHECK-NEXT: Extern
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __const (0x2)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x80)
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# CHECK-NEXT: WeakDef (0x80)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _local ({{[0-9]+}})
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __text (0x1)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x0)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _local_data ({{[0-9]+}})
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __const (0x2)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x0)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _weak ({{[0-9]+}})
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __text (0x1)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x80)
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# CHECK-NEXT: WeakDef (0x80)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _weak_data ({{[0-9]+}})
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __const (0x2)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x80)
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# CHECK-NEXT: WeakDef (0x80)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: _weak_global ({{[0-9]+}})
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# CHECK-NEXT: Extern
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# CHECK-NEXT: Type: Section (0xE)
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# CHECK-NEXT: Section: __text (0x1)
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# CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-NEXT: Flags [ (0x80)
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# CHECK-NEXT: WeakDef (0x80)
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# CHECK-NEXT: ]
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: }
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# CHECK-NEXT: ]
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.globl _global
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_global:
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_local:
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.weak_definition _weak
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_weak:
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.weak_definition _weak_global
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.globl _weak_global
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_weak_global:
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.section __TEXT,__const
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.globl _global_data
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_global_data:
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_local_data:
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.weak_definition _weak_data
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_weak_data:

‎llvm/test/tools/llvm-objcopy/MachO/weaken.s

Lines changed: 89 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,89 @@
1+
# REQUIRES: x86-registered-target
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# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-macos %s -o %t
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# RUN: llvm-objcopy -W _func %t %t2
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# RUN: llvm-readobj --symbols %t2 | FileCheck %s -check-prefix=CHECK-1
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# CHECK-1: Symbol {
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# CHECK-1-NEXT: Name: _foo (1)
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# CHECK-1-NEXT: Extern
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# CHECK-1-NEXT: Type: Section (0xE)
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# CHECK-1-NEXT: Section: __const (0x2)
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# CHECK-1-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-1-NEXT: Flags [ (0x0)
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# CHECK-1-NEXT: ]
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# CHECK-1-NEXT: Value: 0x0
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# CHECK-1-NEXT: }
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# CHECK-1-NEXT: Symbol {
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# CHECK-1-NEXT: Name: _func (6)
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# CHECK-1-NEXT: Extern
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# CHECK-1-NEXT: Type: Section (0xE)
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# CHECK-1-NEXT: Section: __text (0x1)
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# CHECK-1-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-1-NEXT: Flags [ (0x80)
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# CHECK-1-NEXT: WeakDef (0x80)
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# CHECK-1-NEXT: ]
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# CHECK-1-NEXT: Value: 0x0
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# CHECK-1-NEXT: }
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# RUN: echo _foo > %t.weaken.txt
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# RUN: echo _func >> %t.weaken.txt
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# RUN: llvm-objcopy --weaken-symbols %t.weaken.txt %t %t3
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# RUN: llvm-readobj --symbols %t3 | FileCheck %s -check-prefix=CHECK-2
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# CHECK-2: Symbol {
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# CHECK-2-NEXT: Name: _foo (1)
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# CHECK-2-NEXT: Extern
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# CHECK-2-NEXT: Type: Section (0xE)
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# CHECK-2-NEXT: Section: __const (0x2)
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# CHECK-2-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-2-NEXT: Flags [ (0x80)
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# CHECK-2-NEXT: WeakDef (0x80)
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# CHECK-2-NEXT: ]
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# CHECK-2-NEXT: Value: 0x0
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# CHECK-2-NEXT: }
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# CHECK-2-NEXT: Symbol {
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# CHECK-2-NEXT: Name: _func (6)
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# CHECK-2-NEXT: Extern
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# CHECK-2-NEXT: Type: Section (0xE)
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# CHECK-2-NEXT: Section: __text (0x1)
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# CHECK-2-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-2-NEXT: Flags [ (0x80)
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# CHECK-2-NEXT: WeakDef (0x80)
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# CHECK-2-NEXT: ]
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# CHECK-2-NEXT: Value: 0x0
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# CHECK-2-NEXT: }
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## Verify --weaken-symbol plays nice with --redefine-sym.
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# RUN: llvm-objcopy -W _foo --redefine-sym _foo=_bar %t %t4
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# RUN: llvm-readobj --symbols %t4 | FileCheck %s -check-prefix=CHECK-3
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# CHECK-3: Symbol {
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# CHECK-3-NEXT: Name: _bar (1)
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# CHECK-3-NEXT: Extern
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# CHECK-3-NEXT: Type: Section (0xE)
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# CHECK-3-NEXT: Section: __const (0x2)
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# CHECK-3-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-3-NEXT: Flags [ (0x80)
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# CHECK-3-NEXT: WeakDef (0x80)
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# CHECK-3-NEXT: ]
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# CHECK-3-NEXT: Value: 0x0
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# CHECK-3-NEXT: }
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# CHECK-3-NEXT: Symbol {
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# CHECK-3-NEXT: Name: _func (6)
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# CHECK-3-NEXT: Extern
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# CHECK-3-NEXT: Type: Section (0xE)
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# CHECK-3-NEXT: Section: __text (0x1)
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# CHECK-3-NEXT: RefType: UndefinedNonLazy (0x0)
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# CHECK-3-NEXT: Flags [ (0x0)
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# CHECK-3-NEXT: ]
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# CHECK-3-NEXT: Value: 0x0
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# CHECK-3-NEXT: }
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.globl _func
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_func:
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.section __TEXT,__const
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.globl _foo
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_foo:

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