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kongykongy
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Add functionality to llvm-objcopy to remove prefixes
llvm-objcopy has functionality to add prefixes to symbols (--prefix-symbols). This adds an inverse action to undo the modification and return to the original.
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6 files changed

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6 files changed

+134
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lines changed

‎llvm/include/llvm/ObjCopy/CommonConfig.h

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@@ -218,6 +218,7 @@ struct CommonConfig {
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uint64_t PadTo = 0;
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StringRef SplitDWO;
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StringRef SymbolsPrefix;
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StringRef SymbolsPrefixRemove;
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StringRef AllocSectionsPrefix;
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DiscardType DiscardMode = DiscardType::None;
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‎llvm/lib/ObjCopy/ConfigManager.cpp

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@@ -15,6 +15,7 @@ namespace objcopy {
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Expected<const COFFConfig &> ConfigManager::getCOFFConfig() const {
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if (!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
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!Common.SymbolsPrefixRemove.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() ||
@@ -33,6 +34,7 @@ Expected<const COFFConfig &> ConfigManager::getCOFFConfig() const {
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Expected<const MachOConfig &> ConfigManager::getMachOConfig() const {
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if (!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
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!Common.SymbolsPrefixRemove.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() ||
@@ -54,6 +56,7 @@ Expected<const MachOConfig &> ConfigManager::getMachOConfig() const {
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Expected<const WasmConfig &> ConfigManager::getWasmConfig() const {
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if (!Common.AddGnuDebugLink.empty() || Common.ExtractPartition ||
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!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
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!Common.SymbolsPrefixRemove.empty() ||
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!Common.AllocSectionsPrefix.empty() ||
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Common.DiscardMode != DiscardType::None || !Common.SymbolsToAdd.empty() ||
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!Common.SymbolsToGlobalize.empty() || !Common.SymbolsToLocalize.empty() ||
@@ -74,6 +77,7 @@ Expected<const WasmConfig &> ConfigManager::getWasmConfig() const {
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Expected<const XCOFFConfig &> ConfigManager::getXCOFFConfig() const {
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if (!Common.AddGnuDebugLink.empty() || Common.ExtractPartition ||
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!Common.SplitDWO.empty() || !Common.SymbolsPrefix.empty() ||
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!Common.SymbolsPrefixRemove.empty() ||
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!Common.AllocSectionsPrefix.empty() ||
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Common.DiscardMode != DiscardType::None || !Common.AddSection.empty() ||
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!Common.DumpSection.empty() || !Common.SymbolsToAdd.empty() ||

‎llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp

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Original file line numberDiff line numberDiff line change
@@ -329,6 +329,11 @@ static Error updateAndRemoveSymbols(const CommonConfig &Config,
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if (I != Config.SymbolsToRename.end())
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Sym.Name = std::string(I->getValue());
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if (!Config.SymbolsPrefixRemove.empty() && Sym.Type != STT_SECTION)
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if (Sym.Name.compare(0, Config.SymbolsPrefixRemove.size(),
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Config.SymbolsPrefixRemove) == 0)
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Sym.Name = Sym.Name.substr(Config.SymbolsPrefixRemove.size());
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if (!Config.SymbolsPrefix.empty() && Sym.Type != STT_SECTION)
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Sym.Name = (Config.SymbolsPrefix + Sym.Name).str();
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});

‎llvm/test/tools/llvm-objcopy/ELF/prefix-symbols-remove.test

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,115 @@
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# RUN: yaml2obj %s -o %t
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# RUN: llvm-objcopy --remove-prefix-symbols __pf_ %t %t2
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# RUN: llvm-readobj --symbols %t2 | FileCheck %s
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## Show that an empty string is permitted as the argument to
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## --remove-prefix-symbols.
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# RUN: llvm-objcopy --remove-prefix-symbols= %t2 %t3
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# RUN: cmp %t2 %t3
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## When both options are present, llvm-objcopy should remove
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## prefixes first, before adding prefixes.
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# RUN: llvm-objcopy --prefix-symbols=AAA --remove-prefix-symbols=AAA %t %t4
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# RUN: llvm-objcopy --prefix-symbols=AAA %t %t5
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# RUN: cmp %t4 %t5
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!ELF
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FileHeader:
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Class: ELFCLASS64
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Data: ELFDATA2LSB
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Type: ET_REL
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Machine: EM_X86_64
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Sections:
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- Name: .text
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Type: SHT_PROGBITS
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Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
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Address: 0x1000
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AddressAlign: 0x0000000000000010
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Size: 64
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Symbols:
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- Name: __pf_foo
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Type: STT_SECTION
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Section: .text
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- Name: __pf_bar
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Type: STT_FILE
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Section: .text
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- Name: foobar
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Type: STT_FUNC
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Section: .text
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Binding: STB_GLOBAL
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- Name: foo__pf_bar1
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Type: STT_FUNC
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Section: .text
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Binding: STB_GLOBAL
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- Name: __pf_foo__pf_bar2
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Type: STT_FUNC
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Section: .text
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Binding: STB_GLOBAL
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- Name: undef
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Binding: STB_GLOBAL
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# CHECK: Symbols [
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name:
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Local
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# CHECK-NEXT: Type: None
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: Undefined
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: __pf_foo
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Local
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# CHECK-NEXT: Type: Section
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: .text
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: bar
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Local
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# CHECK-NEXT: Type: File
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: .text
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: foobar
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Global
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# CHECK-NEXT: Type: Function
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: .text
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: foo__pf_bar1
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Global
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# CHECK-NEXT: Type: Function
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: .text
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: foo__pf_bar2
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Global
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# CHECK-NEXT: Type: Function
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: .text
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# CHECK-NEXT: }
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# CHECK-NEXT: Symbol {
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# CHECK-NEXT: Name: undef
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# CHECK-NEXT: Value: 0x0
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# CHECK-NEXT: Size: 0
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# CHECK-NEXT: Binding: Global
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# CHECK-NEXT: Type: None
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# CHECK-NEXT: Other: 0
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# CHECK-NEXT: Section: Undefined
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# CHECK-NEXT: }
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# CHECK-NEXT:]

‎llvm/tools/llvm-objcopy/ObjcopyOptions.cpp

Lines changed: 4 additions & 0 deletions
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@@ -731,7 +731,11 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
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llvm::crc32(arrayRefFromStringRef(Debug->getBuffer()));
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}
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Config.SplitDWO = InputArgs.getLastArgValue(OBJCOPY_split_dwo);
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Config.SymbolsPrefix = InputArgs.getLastArgValue(OBJCOPY_prefix_symbols);
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Config.SymbolsPrefixRemove =
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InputArgs.getLastArgValue(OBJCOPY_remove_prefix_symbols);
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Config.AllocSectionsPrefix =
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InputArgs.getLastArgValue(OBJCOPY_prefix_alloc_sections);
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if (auto Arg = InputArgs.getLastArg(OBJCOPY_extract_partition))

‎llvm/tools/llvm-objcopy/ObjcopyOpts.td

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@@ -203,6 +203,11 @@ defm dump_section
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defm prefix_symbols
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: Eq<"prefix-symbols", "Add <prefix> to the start of every symbol name">,
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MetaVarName<"prefix">;
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defm remove_prefix_symbols
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: Eq<"remove-prefix-symbols",
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"Remove <prefix> from the start of every symbol name. No-op for symbols that do not start "
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"with <prefix>">,
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MetaVarName<"prefix">;
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defm prefix_alloc_sections
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: Eq<"prefix-alloc-sections", "Add <prefix> to the start of every allocated section name">,

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