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CMake: Don't assume that -fvisibility=hidden is supported outside Windows.
The original code was good enough for supporting GNU/Linux and a few others but it wasn't very portable. CMake doesn't support Solaris Studio's -xldscope=hidden. If it ever does, things should still work with this commit as Solaris Studio supports not only its own __global but also the GNU C __attribute__((visibility("default"))). Support for the attribute was added in 2007 to Sun Studio 12 compiler version 5.9.
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1 changed files with 22 additions and 4 deletions
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@ -1144,10 +1144,28 @@ if(ALLOW_ARM64_CRC32)
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endif()
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# Support -fvisiblity=hidden when building shared liblzma.
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# These lines do nothing on Windows (even under Cygwin).
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# HAVE_VISIBILITY should always be defined to 0 or 1.
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if(BUILD_SHARED_LIBS)
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# Symbol visibility support:
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#
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# The C_VISIBILITY_PRESET property takes care of adding the compiler
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# option -fvisibility=hidden (or equivalent) if and only if it is supported.
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#
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# HAVE_VISIBILITY should always be defined to 0 or 1. It tells liblzma
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# if __attribute__((__visibility__("default")))
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# and __attribute__((__visibility__("hidden"))) are supported.
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# Those are useful only when the compiler supports -fvisibility=hidden
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# or such option so HAVE_VISIBILITY should be 1 only when both option and
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# the attribute support are present. HAVE_VISIBILITY is ignored on Windows
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# and Cygwin by the liblzma C code; __declspec(dllexport) is used instead.
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#
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# CMake's GenerateExportHeader module is too fancy since liblzma already
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# has the necessary macros. Instead, check CMake's internal variable
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# CMAKE_C_COMPILE_OPTIONS_VISIBILITY (it's the C-specific variant of
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# CMAKE_<LANG>_COMPILE_OPTIONS_VISIBILITY) which contains the compiler
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# command line option for visibility support. It's empty or unset when
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# visibility isn't supported. (It was added to CMake 2.8.12 in the commit
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# 0e9f4bc00c6b26f254e74063e4026ac33b786513 in 2013.) This way we don't
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# set HAVE_VISIBILITY to 1 when visibility isn't actually supported.
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if(BUILD_SHARED_LIBS AND CMAKE_C_COMPILE_OPTIONS_VISIBILITY)
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set_target_properties(liblzma PROPERTIES C_VISIBILITY_PRESET hidden)
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target_compile_definitions(liblzma PRIVATE HAVE_VISIBILITY=1)
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else()
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