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MaskRayMaskRay
committedOct 2, 2019
[llvm-objcopy] Add --set-section-alignment
Fixes PR43181. This option was recently added to GNU objcopy (binutils PR24942). `llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8` can set the alignment of .data. Reviewed By: grimar, jhenderson, rupprecht Differential Revision: https://reviews.llvm.org/D67656 llvm-svn: 373461
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llvmorg-21-initllvmorg-10.0.0-rc1
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-11
lines changed

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+119
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‎llvm/docs/CommandGuide/llvm-objcopy.rst

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@@ -82,6 +82,11 @@ multiple file formats.
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Remove the specified section from the output. Can be specified multiple times
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to remove multiple sections simultaneously.
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.. option:: --set-section-alignment <section>=<align>
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Set the alignment of section ``<section>`` to `<align>``. Can be specified
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multiple times to update multiple sections.
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.. option:: --strip-all-gnu
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Remove all symbols, debug sections and relocations from the output. This option

‎llvm/test/tools/llvm-objcopy/ELF/binary-input.test

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@@ -110,3 +110,11 @@
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# CHECK-NEXT: Section: Absolute
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# CHECK-NEXT: }
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# CHECK-NEXT: ]
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## The alignment can be changed by --set-section-alignment.
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# RUN: llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8 %t.x-txt %t2.o
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# RUN: llvm-readobj --sections %t2.o | FileCheck --check-prefix=ALIGN %s
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# ALIGN: Name: .data
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# ALIGN: AddressAlignment:
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# ALIGN-SAME: 8{{$}}

‎llvm/test/tools/llvm-objcopy/ELF/set-section-alignment.test

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@@ -0,0 +1,54 @@
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# RUN: yaml2obj %s -o %t
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# RUN: llvm-objcopy --set-section-alignment .foo=4 --set-section-alignment .bar=0x5 \
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# RUN: --set-section-alignment .baz=0 %t %t.2
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# RUN: llvm-readobj --sections %t.2 | FileCheck --check-prefix=CHECK %s
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# CHECK: Name: .foo
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# CHECK: AddressAlignment:
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# CHECK-SAME: 4{{$}}
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# CHECK: Name: .bar
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# CHECK: AddressAlignment:
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# CHECK-SAME: 5{{$}}
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# CHECK: Name: .baz
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# CHECK: AddressAlignment:
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# CHECK-SAME: 0{{$}}
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## If a section is specified multiple times, the last wins.
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# RUN: llvm-objcopy --set-section-alignment .foo=4 --set-section-alignment=.foo=7 %t %t.3
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# RUN: llvm-readobj --sections %t.3 | FileCheck --check-prefix=MULTI %s
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# MULTI: Name: .foo
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# MULTI: AddressAlignment:
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# MULTI-SAME: 7{{$}}
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## Ignore the option if the section does not exist.
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# RUN: llvm-objcopy --set-section-alignment .not_exist=4 %t.3 %t.4
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# RUN: cmp %t.3 %t.4
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# RUN: not llvm-objcopy --set-section-alignment=.foo %t /dev/null 2>&1 | \
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# RUN: FileCheck --check-prefix=MISSING-EQUAL %s
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# MISSING-EQUAL: error: bad format for --set-section-alignment: missing '='
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# RUN: not llvm-objcopy --set-section-alignment==4 %t /dev/null 2>&1 | \
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# RUN: FileCheck --check-prefix=MISSING-SECTION %s
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# MISSING-SECTION: error: bad format for --set-section-alignment: missing section name
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# RUN: not llvm-objcopy --set-section-alignment=.foo=bar %t /dev/null 2>&1 | \
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# RUN: FileCheck --check-prefix=INVALID-ALIGN %s
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# INVALID-ALIGN: error: invalid alignment for --set-section-alignment: 'bar'
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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: .foo
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Type: SHT_PROGBITS
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- Name: .bar
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Type: SHT_NOBITS
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- Name: .baz
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Type: SHT_NOTE
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AddressAlign: 4

‎llvm/tools/llvm-objcopy/COFF/COFFObjcopy.cpp

+5-4
Original file line numberDiff line numberDiff line change
@@ -208,10 +208,11 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
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!Config.SymbolsToGlobalize.empty() || !Config.SymbolsToKeep.empty() ||
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!Config.SymbolsToLocalize.empty() || !Config.SymbolsToWeaken.empty() ||
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!Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() ||
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!Config.SetSectionFlags.empty() || !Config.SymbolsToRename.empty() ||
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Config.ExtractDWO || Config.KeepFileSymbols || Config.LocalizeHidden ||
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Config.PreserveDates || Config.StripDWO || Config.StripNonAlloc ||
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Config.StripSections || Config.Weaken || Config.DecompressDebugSections ||
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!Config.SetSectionAlignment.empty() || !Config.SetSectionFlags.empty() ||
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!Config.SymbolsToRename.empty() || Config.ExtractDWO ||
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Config.KeepFileSymbols || Config.LocalizeHidden || Config.PreserveDates ||
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Config.StripDWO || Config.StripNonAlloc || Config.StripSections ||
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Config.Weaken || Config.DecompressDebugSections ||
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Config.DiscardMode == DiscardType::Locals ||
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!Config.SymbolsToAdd.empty() || Config.EntryExpr) {
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return createStringError(llvm::errc::invalid_argument,

‎llvm/tools/llvm-objcopy/CopyConfig.cpp

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Original file line numberDiff line numberDiff line change
@@ -155,6 +155,25 @@ static Expected<SectionRename> parseRenameSectionValue(StringRef FlagValue) {
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return SR;
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}
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static Expected<std::pair<StringRef, uint64_t>>
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parseSetSectionAlignment(StringRef FlagValue) {
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if (!FlagValue.contains('='))
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return createStringError(
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errc::invalid_argument,
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"bad format for --set-section-alignment: missing '='");
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auto Split = StringRef(FlagValue).split('=');
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if (Split.first.empty())
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return createStringError(
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errc::invalid_argument,
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"bad format for --set-section-alignment: missing section name");
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uint64_t NewAlign;
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if (Split.second.getAsInteger(0, NewAlign))
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return createStringError(errc::invalid_argument,
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"invalid alignment for --set-section-alignment: '%s'",
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Split.second.str().c_str());
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return std::make_pair(Split.first, NewAlign);
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}
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static Expected<SectionFlagsUpdate>
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parseSetSectionFlagValue(StringRef FlagValue) {
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if (!StringRef(FlagValue).contains('='))
@@ -489,6 +508,13 @@ Expected<DriverConfig> parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
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"multiple renames of section '%s'",
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SR->OriginalName.str().c_str());
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}
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for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_alignment)) {
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Expected<std::pair<StringRef, uint64_t>> NameAndAlign =
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parseSetSectionAlignment(Arg->getValue());
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if (!NameAndAlign)
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return NameAndAlign.takeError();
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Config.SetSectionAlignment[NameAndAlign->first] = NameAndAlign->second;
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}
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for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_flags)) {
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Expected<SectionFlagsUpdate> SFU =
494520
parseSetSectionFlagValue(Arg->getValue());

‎llvm/tools/llvm-objcopy/CopyConfig.h

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@@ -161,6 +161,7 @@ struct CopyConfig {
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// Map options
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StringMap<SectionRename> SectionsToRename;
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StringMap<uint64_t> SetSectionAlignment;
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StringMap<SectionFlagsUpdate> SetSectionFlags;
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StringMap<StringRef> SymbolsToRename;
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‎llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp

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Original file line numberDiff line numberDiff line change
@@ -670,6 +670,14 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj,
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}
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}
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if (!Config.SetSectionAlignment.empty()) {
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for (SectionBase &Sec : Obj.sections()) {
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auto I = Config.SetSectionAlignment.find(Sec.Name);
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if (I != Config.SetSectionAlignment.end())
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Sec.Align = I->second;
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}
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}
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if (!Config.SetSectionFlags.empty()) {
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for (auto &Sec : Obj.sections()) {
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const auto Iter = Config.SetSectionFlags.find(Sec.Name);

‎llvm/tools/llvm-objcopy/MachO/MachOObjcopy.cpp

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@@ -31,13 +31,14 @@ static Error handleArgs(const CopyConfig &Config, Object &Obj) {
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!Config.SymbolsToKeepGlobal.empty() || !Config.SectionsToRename.empty() ||
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!Config.SymbolsToRename.empty() ||
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!Config.UnneededSymbolsToRemove.empty() ||
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!Config.SetSectionFlags.empty() || !Config.ToRemove.empty() ||
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Config.ExtractDWO || Config.KeepFileSymbols || Config.LocalizeHidden ||
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Config.PreserveDates || Config.StripDWO || Config.StripNonAlloc ||
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Config.StripSections || Config.Weaken || Config.DecompressDebugSections ||
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Config.StripDebug || Config.StripNonAlloc || Config.StripSections ||
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Config.StripUnneeded || Config.DiscardMode != DiscardType::None ||
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!Config.SymbolsToAdd.empty() || Config.EntryExpr) {
34+
!Config.SetSectionAlignment.empty() || !Config.SetSectionFlags.empty() ||
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!Config.ToRemove.empty() || Config.ExtractDWO || Config.KeepFileSymbols ||
36+
Config.LocalizeHidden || Config.PreserveDates || Config.StripDWO ||
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Config.StripNonAlloc || Config.StripSections || Config.Weaken ||
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Config.DecompressDebugSections || Config.StripDebug ||
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Config.StripNonAlloc || Config.StripSections || Config.StripUnneeded ||
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Config.DiscardMode != DiscardType::None || !Config.SymbolsToAdd.empty() ||
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Config.EntryExpr) {
4142
return createStringError(llvm::errc::invalid_argument,
4243
"option not supported by llvm-objcopy for MachO");
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}

‎llvm/tools/llvm-objcopy/ObjcopyOpts.td

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@@ -75,6 +75,10 @@ defm add_section
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"Make a section named <section> with the contents of <file>.">,
7676
MetaVarName<"section=file">;
7777

78+
defm set_section_alignment
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: Eq<"set-section-alignment", "Set alignment for a given section.">,
80+
MetaVarName<"section=align">;
81+
7882
defm set_section_flags
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: Eq<"set-section-flags",
8084
"Set section flags for a given section. Flags supported for GNU "

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