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[llvm-objcopy] Add --set-symbol-visibility and --set-symbols-visibility options (#80872)
Add options --set-symbol-visibility and --set-symbols-visibility to manually change the visibility of symbols. There is already an option to set the visibility of newly added symbols via --add-symbol and --new-symbol-visibility. This option will allow to change the visibility of already existing symbols.
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‎llvm/docs/CommandGuide/llvm-objcopy.rst

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@@ -455,6 +455,15 @@ them.
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Set the start address of the output to ``<addr>``. Overrides any previously
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specified :option:`--change-start` or :option:`--adjust-start` options.
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.. option:: --set-symbol-visibility <symbol>=<visibility>
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Change the visibility of a symbol to the specified value.
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.. option:: --set-symbols-visibility <filename>=<visibility>
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Read a list of symbols from <filename> and change their visibility to the
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specified value. Visibility values: default, internal, hidden, protected.
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.. option:: --split-dwo <dwo-file>
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Equivalent to running :program:`llvm-objcopy` with :option:`--extract-dwo` and

‎llvm/docs/ReleaseNotes.rst

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if it's not specified with the ``--format`` argument and cannot be inferred from
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input files.
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* llvm-objcopy now supports ``--set-symbol-visibility`` and
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``--set-symbols-visibility`` options for ELF input to change the
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visibility of symbols.
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Changes to LLDB
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---------------------------------
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‎llvm/include/llvm/ObjCopy/ELF/ELFConfig.h

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#ifndef LLVM_OBJCOPY_ELF_ELFCONFIG_H
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#define LLVM_OBJCOPY_ELF_ELFCONFIG_H
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#include "llvm/ObjCopy/CommonConfig.h"
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#include "llvm/Object/ELFTypes.h"
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namespace llvm {
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struct ELFConfig {
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uint8_t NewSymbolVisibility = (uint8_t)ELF::STV_DEFAULT;
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std::vector<std::pair<NameMatcher, uint8_t>> SymbolsToSetVisibility;
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// ELF entry point address expression. The input parameter is an entry point
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// address in the input ELF file. The entry address in the output file is
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// calculated with EntryExpr(input_address), when either --set-start or

‎llvm/lib/ObjCopy/ELF/ELFObjcopy.cpp

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@@ -300,6 +300,10 @@ static Error updateAndRemoveSymbols(const CommonConfig &Config,
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Config.SymbolsToLocalize.matches(Sym.Name)))
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Sym.Binding = STB_LOCAL;
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for (auto &[Matcher, Visibility] : ELFConfig.SymbolsToSetVisibility)
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if (Matcher.matches(Sym.Name))
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Sym.Visibility = Visibility;
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// Note: these two globalize flags have very similar names but different
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// meanings:
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//

‎llvm/test/tools/llvm-objcopy/ELF/set-symbol-visibility.test

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# RUN: yaml2obj --docnum=1 %s -o %t.o
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# RUN: echo '.*' > %t.symbols.regex
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## Check that the visibility of all symbols is properly set to DEFAULT.
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# RUN: llvm-objcopy %t.o %t0.o --set-symbols-visibility=%t.symbols.regex=default --regex
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# RUN: llvm-readelf -s %t0.o | FileCheck %s --check-prefix=DEF
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# DEF-DAG: DEFAULT 1 default_local
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# DEF-DAG: DEFAULT 1 internal_local
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# DEF-DAG: DEFAULT 1 hidden_local
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# DEF-DAG: DEFAULT 1 protected_local
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# DEF-DAG: DEFAULT 1 default_global
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# DEF-DAG: DEFAULT 1 default_weak
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# DEF-DAG: DEFAULT 1 internal_global
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# DEF-DAG: DEFAULT 1 internal_weak
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# DEF-DAG: DEFAULT 1 hidden_global
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# DEF-DAG: DEFAULT 1 hidden_weak
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# DEF-DAG: DEFAULT 1 protected_global
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# DEF-DAG: DEFAULT 1 protected_weak
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## Check that the visibility of all symbols is properly set to HIDDEN.
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# RUN: llvm-objcopy %t.o %t1.o --set-symbols-visibility=%t.symbols.regex=hidden --regex
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# RUN: llvm-readelf -s %t1.o | FileCheck %s --check-prefix=HID
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# HID-DAG: HIDDEN 1 default_local
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# HID-DAG: HIDDEN 1 internal_local
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# HID-DAG: HIDDEN 1 hidden_local
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# HID-DAG: HIDDEN 1 protected_local
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# HID-DAG: HIDDEN 1 default_global
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# HID-DAG: HIDDEN 1 default_weak
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# HID-DAG: HIDDEN 1 internal_global
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# HID-DAG: HIDDEN 1 internal_weak
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# HID-DAG: HIDDEN 1 hidden_global
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# HID-DAG: HIDDEN 1 hidden_weak
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# HID-DAG: HIDDEN 1 protected_global
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# HID-DAG: HIDDEN 1 protected_weak
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## Check that the visibility of all symbols is properly set to PROTECTED.
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# RUN: llvm-objcopy %t.o %t2.o --set-symbols-visibility=%t.symbols.regex=protected --regex
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# RUN: llvm-readelf -s %t2.o | FileCheck %s --check-prefix=PRO
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# PRO-DAG: PROTECTED 1 default_local
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# PRO-DAG: PROTECTED 1 internal_local
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# PRO-DAG: PROTECTED 1 hidden_local
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# PRO-DAG: PROTECTED 1 protected_local
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# PRO-DAG: PROTECTED 1 default_global
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# PRO-DAG: PROTECTED 1 default_weak
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# PRO-DAG: PROTECTED 1 internal_global
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# PRO-DAG: PROTECTED 1 internal_weak
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# PRO-DAG: PROTECTED 1 hidden_global
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# PRO-DAG: PROTECTED 1 hidden_weak
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# PRO-DAG: PROTECTED 1 protected_global
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# PRO-DAG: PROTECTED 1 protected_weak
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## Check that the visibility of all symbols is properly set to INTERNAL.
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# RUN: llvm-objcopy %t.o %t3.o --set-symbols-visibility=%t.symbols.regex=internal --regex
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# RUN: llvm-readelf -s %t3.o | FileCheck %s --check-prefix=INT
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# INT-DAG: INTERNAL 1 default_local
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# INT-DAG: INTERNAL 1 internal_local
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# INT-DAG: INTERNAL 1 hidden_local
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# INT-DAG: INTERNAL 1 protected_local
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# INT-DAG: INTERNAL 1 default_global
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# INT-DAG: INTERNAL 1 default_weak
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# INT-DAG: INTERNAL 1 internal_global
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# INT-DAG: INTERNAL 1 internal_weak
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# INT-DAG: INTERNAL 1 hidden_global
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# INT-DAG: INTERNAL 1 hidden_weak
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# INT-DAG: INTERNAL 1 protected_global
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# INT-DAG: INTERNAL 1 protected_weak
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## Check that setting the visibility of certain symbols that were read from
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## a file does not affect other symbols.
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# RUN: echo -e "default_local\ninternal_local" > %t.symbol.list
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# RUN: llvm-objcopy %t.o %t4.o --set-symbols-visibility=%t.symbol.list=hidden
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# RUN: llvm-readelf -s %t4.o | FileCheck %s --check-prefix=FILE
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# FILE-DAG: HIDDEN 1 default_local
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# FILE-DAG: HIDDEN 1 internal_local
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## Unaffected symbols:
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# FILE-DAG: HIDDEN 1 hidden_local
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# FILE-DAG: PROTECTED 1 protected_local
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# FILE-DAG: DEFAULT 1 default_global
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# FILE-DAG: DEFAULT 1 default_weak
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# FILE-DAG: INTERNAL 1 internal_global
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# FILE-DAG: INTERNAL 1 internal_weak
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# FILE-DAG: HIDDEN 1 hidden_global
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# FILE-DAG: HIDDEN 1 hidden_weak
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# FILE-DAG: PROTECTED 1 protected_global
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# FILE-DAG: PROTECTED 1 protected_weak
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## Check that the visibility of a single symbol is set correctly,
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## and that no other symbols are affected.
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# RUN: llvm-objcopy %t.o %t5.o --set-symbol-visibility=default_local=hidden \
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# RUN: --set-symbol-visibility=internal_local=protected \
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# RUN: --set-symbol-visibility=hidden_local=internal \
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# RUN: --set-symbol-visibility=protected_local=default
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# RUN: llvm-readelf -s %t5.o | FileCheck %s --check-prefix=SINGLE
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# SINGLE-DAG: HIDDEN 1 default_local
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# SINGLE-DAG: PROTECTED 1 internal_local
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# SINGLE-DAG: INTERNAL 1 hidden_local
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# SINGLE-DAG: DEFAULT 1 protected_local
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## Unaffected symbols:
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# SINGLE-DAG: DEFAULT 1 default_global
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# SINGLE-DAG: DEFAULT 1 default_weak
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# SINGLE-DAG: INTERNAL 1 internal_global
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# SINGLE-DAG: INTERNAL 1 internal_weak
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# SINGLE-DAG: HIDDEN 1 hidden_global
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# SINGLE-DAG: HIDDEN 1 hidden_weak
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# SINGLE-DAG: PROTECTED 1 protected_global
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# SINGLE-DAG: PROTECTED 1 protected_weak
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## Check that the visibility of symbols specified by a regex are set correctly,
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## and that no other symbols are affected.
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# RUN: llvm-objcopy %t.o %t6.o --set-symbol-visibility='.*'_local=hidden --regex
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# RUN: llvm-readelf -s %t6.o | FileCheck %s --check-prefix=REGEX
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# REGEX-DAG: HIDDEN 1 default_local
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# REGEX-DAG: HIDDEN 1 internal_local
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# REGEX-DAG: HIDDEN 1 hidden_local
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# REGEX-DAG: HIDDEN 1 protected_local
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## Unaffected symbols:
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# REGEX-DAG: DEFAULT 1 default_global
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# REGEX-DAG: DEFAULT 1 default_weak
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# REGEX-DAG: INTERNAL 1 internal_global
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# REGEX-DAG: INTERNAL 1 internal_weak
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# REGEX-DAG: HIDDEN 1 hidden_global
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# REGEX-DAG: HIDDEN 1 hidden_weak
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# REGEX-DAG: PROTECTED 1 protected_global
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# REGEX-DAG: PROTECTED 1 protected_weak
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## Check that the visibility of symbols specified by a wildcard are set correctly,
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## and that no other symbols are affected.
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# RUN: llvm-objcopy %t.o %t7.o --set-symbol-visibility='*_local'=hidden --wildcard
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# RUN: llvm-readelf -s %t7.o | FileCheck %s --check-prefix=WILDCARD
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# WILDCARD-DAG: HIDDEN 1 default_local
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# WILDCARD-DAG: HIDDEN 1 internal_local
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# WILDCARD-DAG: HIDDEN 1 hidden_local
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# WILDCARD-DAG: HIDDEN 1 protected_local
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## Unaffected symbols:
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# WILDCARD-DAG: DEFAULT 1 default_global
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# WILDCARD-DAG: DEFAULT 1 default_weak
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# WILDCARD-DAG: INTERNAL 1 internal_global
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# WILDCARD-DAG: INTERNAL 1 internal_weak
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# WILDCARD-DAG: HIDDEN 1 hidden_global
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# WILDCARD-DAG: HIDDEN 1 hidden_weak
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# WILDCARD-DAG: PROTECTED 1 protected_global
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# WILDCARD-DAG: PROTECTED 1 protected_weak
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## Check that the latest option that matches the same symbols as any of the previous
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## options overwrites the visibility of these symbols.
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# RUN: echo -e '*_weak\n*_local' > %t.symbols.pattern
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# RUN: llvm-objcopy %t.o %t8.o --set-symbol-visibility='default_*'=hidden \
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# RUN: --set-symbol-visibility='internal_*'=hidden \
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# RUN: --set-symbols-visibility=%t.symbols.pattern=protected \
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# RUN: --wildcard
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# RUN: llvm-readelf -s %t8.o | FileCheck %s --check-prefix=REWRITE
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# REWRITE-DAG: PROTECTED 1 default_local
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# REWRITE-DAG: HIDDEN 1 default_global
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# REWRITE-DAG: PROTECTED 1 default_weak
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# REWRITE-DAG: PROTECTED 1 internal_local
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# REWRITE-DAG: HIDDEN 1 internal_global
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# REWRITE-DAG: PROTECTED 1 internal_weak
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# REWRITE-DAG: PROTECTED 1 hidden_local
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# REWRITE-DAG: PROTECTED 1 hidden_weak
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# REWRITE-DAG: PROTECTED 1 protected_local
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# REWRITE-DAG: PROTECTED 1 protected_weak
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## Unaffected symbols:
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# REWRITE-DAG: HIDDEN 1 hidden_global
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# REWRITE-DAG: PROTECTED 1 protected_global
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## Check that a symbol name with a special charater is treated as a plain name
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## when pattern matching options are not enabled.
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# RUN: yaml2obj --docnum=2 %s -o %t9.o
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# RUN: llvm-objcopy %t9.o --set-symbol-visibility='f*o'=hidden
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# RUN: llvm-readelf -s %t9.o | FileCheck %s --check-prefix=SPECIAL
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# SPECIAL-DAG: HIDDEN 1 f*o
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## Unaffected symbol:
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# SPECIAL-DAG: DEFAULT 1 foo
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# RUN: yaml2obj --docnum=3 %s -o %t10.o
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## Check that the visibility of undefined symbols can be changed as well.
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# RUN: llvm-objcopy %t10.o --set-symbol-visibility=foo=hidden
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# RUN: llvm-readelf -s %t10.o | FileCheck %s --check-prefix=UNDEF
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# UNDEF: HIDDEN UND foo
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## Check that passing an invalid visibility type generates an error message.
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# RUN: echo 'foo' > %t.symbols
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# RUN: not llvm-objcopy %t10.o --set-symbols-visibility=%t.symbols=invalid-type 2>&1 | \
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# RUN: FileCheck %s --check-prefix=TYPE
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# RUN: not llvm-objcopy %t10.o --set-symbol-visibility=foo=invalid-type 2>&1 | \
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# RUN: FileCheck %s --check-prefix=TYPE
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# TYPE: error: 'invalid-type' is not a valid symbol visibility
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## Check that omitting the '=' character generates an error.
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# RUN: not llvm-objcopy %t10.o --set-symbols-visibility=%t.symbols,hidden 2>&1 | \
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# RUN: FileCheck %s --check-prefix=FORMAT -DOPTION=--set-symbols-visibility
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# RUN: not llvm-objcopy %t10.o --set-symbol-visibility=foo default 2>&1 | \
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# RUN: FileCheck %s --check-prefix=FORMAT -DOPTION=--set-symbol-visibility
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# FORMAT: error: bad format for [[OPTION]]
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## Check that using an invalid symbol pattern generates an error.
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# RUN: echo '*.' > %t.symbols.regex
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# RUN: not llvm-objcopy %t10.o --set-symbols-visibility=%t.symbols.regex=hidden --regex 2>&1 | \
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# RUN: FileCheck %s --check-prefix=SYMBOL
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# RUN: not llvm-objcopy %t10.o --set-symbol-visibility='*.'=default --regex 2>&1 | \
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# RUN: FileCheck %s --check-prefix=SYMBOL
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# SYMBOL: error: cannot compile regular expression '*.': repetition-operator operand invalid
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## Check passing an invalid filename generates an error.
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# RUN: not llvm-objcopy %t10.o --set-symbols-visibility=no_file=hidden 2>&1 | \
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# RUN: FileCheck %s --check-prefix=NO_FILE -DMSG=%errc_ENOENT
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# NO_FILE: error: 'no_file': [[MSG]]
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---
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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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Symbols:
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- Name: default_local
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Section: .text
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Binding: STB_LOCAL
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- Name: protected_local
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Section: .text
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Binding: STB_LOCAL
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Other: [ STV_PROTECTED ]
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- Name: internal_local
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Section: .text
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Binding: STB_LOCAL
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Other: [ STV_INTERNAL ]
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- Name: hidden_local
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Section: .text
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Binding: STB_LOCAL
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Other: [ STV_HIDDEN ]
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- Name: default_weak
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Section: .text
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Binding: STB_WEAK
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- Name: internal_weak
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Section: .text
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Binding: STB_WEAK
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Other: [ STV_INTERNAL ]
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- Name: hidden_weak
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Section: .text
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Binding: STB_WEAK
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Other: [ STV_HIDDEN ]
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- Name: protected_weak
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Section: .text
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Binding: STB_WEAK
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Other: [ STV_PROTECTED ]
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- Name: default_global
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Section: .text
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Binding: STB_GLOBAL
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- Name: internal_global
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Section: .text
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Binding: STB_GLOBAL
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Other: [ STV_INTERNAL ]
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- Name: hidden_global
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Section: .text
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Binding: STB_GLOBAL
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Other: [ STV_HIDDEN ]
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- Name: protected_global
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Section: .text
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Binding: STB_GLOBAL
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Other: [ STV_PROTECTED ]
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- Name: ignored_name
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Section: .text
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Binding: STB_GLOBAL
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Other: [ STV_INTERNAL ]
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...
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---
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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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Symbols:
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- Name: f*o
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Section: .text
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Binding: STB_LOCAL
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- Name: foo
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Section: .text
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Binding: STB_LOCAL
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...
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---
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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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Symbols:
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- Name: foo
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Binding: STB_LOCAL
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...

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