[libc++] Remove the legacy LIBCXX_LIBCPPABI_VERSION option

[ldionne]

Summary

I think this notion of libc++abi's version was relevant a long time ago
on Apple platforms when we were using a Xcode project to build the library.
As part of moving Apple's build to CMake, D59489 made it possible to
specify the "ABI version" of libc++abi in use. However, it's not possible
to build libc++abi with that old ABI anymore and we don't need the ability
to link against that version from libc++ anymore.

Hence, we can clean this up and stop falsely pretending that libc++abi
has more than one ABI version.

libcxx/CMakeLists.txt

if (NOT ("${LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION}" IN_LIST TYPEINFO_COMPARISON_VALUES))
   message(FATAL_ERROR "Value '${LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION}' is not a valid value for
                        LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION")
 endif()
 
 option(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT "Enable per TU ABI insulation by default. To be used by vendors." OFF)
 set(LIBCXX_ABI_DEFINES "" CACHE STRING "A semicolon separated list of ABI macros to define in the site config header.")
 option(LIBCXX_EXTRA_SITE_DEFINES "Extra defines to add into __config_site")
 option(LIBCXX_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
-set(LIBCXX_LIBCPPABI_VERSION "2" CACHE STRING "Version of libc++abi's ABI to re-export from libc++ when re-exporting is enabled.
-                                               Note that this is not related to the version of libc++'s ABI itself!")
 
 # ABI Library options ---------------------------------------------------------
 if (LIBCXX_TARGETING_MSVC)
   set(LIBCXX_DEFAULT_ABI_LIBRARY "vcruntime")
 elseif (${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
   set(LIBCXX_DEFAULT_ABI_LIBRARY "libcxxrt")
 else()
   set(LIBCXX_DEFAULT_ABI_LIBRARY "libcxxabi")

libcxx/lib/libc++abi.v1.exp

-___cxa_demangle
-___cxa_get_globals
-___cxa_get_globals_fast
-___cxa_guard_abort
-___cxa_guard_acquire
-___cxa_guard_release
-___cxa_pure_virtual
-___cxa_deleted_virtual
-___cxa_vec_cctor
-___cxa_vec_cleanup
-___cxa_vec_ctor
-___cxa_vec_delete
-___cxa_vec_delete2
-___cxa_vec_delete3
-___cxa_vec_dtor
-___cxa_vec_new
-___cxa_vec_new2
-___cxa_vec_new3
-___dynamic_cast
-__ZTIDi
-__ZTIDn
-__ZTIDs
-__ZTIPDi
-__ZTIPDn
-__ZTIPDs
-__ZTIPKDi
-__ZTIPKDn
-__ZTIPKDs
-__ZTSPm
-__ZTSPl
-__ZTSPj
-__ZTSPi
-__ZTSPh
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-__ZTSPe
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-__ZTSPs
-__ZTSPt
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-__ZTSPKe
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-__ZTSPKf
-__ZTSv
-__ZTSt
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-__ZTSm
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-__ZTSh
-__ZTSf
-__ZTSe
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-__ZTSc
-__ZTSw
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-__ZTSy
-__ZTSb
-__ZTSa
-__ZTIPKh
-__ZTIPKf
-__ZTIPKe
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-__ZTIPKc
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-__ZTIPKs
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-__ZTIPKx
-__ZTIPKy
-__ZTIPa
-__ZTIPb
-__ZTIPc
-__ZTIPd
-__ZTIPe
-__ZTIPf
-__ZTIPh
-__ZTVN10__cxxabiv129__pointer_to_member_type_infoE
-__ZTVN10__cxxabiv116__enum_type_infoE
-__ZTVN10__cxxabiv117__array_type_infoE
-__ZTVN10__cxxabiv117__class_type_infoE
-__ZTVN10__cxxabiv117__pbase_type_infoE
-__ZTVN10__cxxabiv119__pointer_type_infoE
-__ZTVN10__cxxabiv120__function_type_infoE
-__ZTVN10__cxxabiv120__si_class_type_infoE
-__ZTVN10__cxxabiv121__vmi_class_type_infoE
-__ZTVN10__cxxabiv123__fundamental_type_infoE
-__ZTIa
-__ZTIb
-__ZTIc
-__ZTId
-__ZTIe
-__ZTIf
-__ZTIh
-__ZTIi
-__ZTIj
-__ZTIl
-__ZTIm
-__ZTIs
-__ZTIt
-__ZTSN10__cxxabiv129__pointer_to_member_type_infoE
-__ZTSN10__cxxabiv123__fundamental_type_infoE
-__ZTSN10__cxxabiv121__vmi_class_type_infoE
-__ZTSN10__cxxabiv120__si_class_type_infoE
-__ZTSN10__cxxabiv120__function_type_infoE
-__ZTSN10__cxxabiv119__pointer_type_infoE
-__ZTSN10__cxxabiv117__pbase_type_infoE
-__ZTSN10__cxxabiv117__class_type_infoE
-__ZTSN10__cxxabiv117__array_type_infoE
-__ZTSN10__cxxabiv116__enum_type_infoE
-__ZTIy
-__ZTIx
-__ZTIw
-__ZTIv

libcxx/src/CMakeLists.txt

if (APPLE AND LIBCXX_CXX_ABI STREQUAL "libcxxabi"
             AND NOT DEFINED LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS
             AND NOT LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY)
     set(LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS ON)
   endif()
 
   if (LIBCXX_OSX_REEXPORT_LIBCXXABI_SYMBOLS)
     target_link_libraries(cxx_shared PRIVATE
       "-Wl,-unexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/libc++unexp.exp"
-      "-Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/libc++abi.v${LIBCXX_LIBCPPABI_VERSION}.exp"
+      "-Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/libc++abi.exp"
       "-Wl,-force_symbols_not_weak_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/notweak.exp"
       "-Wl,-force_symbols_weak_list,${CMAKE_CURRENT_SOURCE_DIR}/../lib/weak.exp")
 
     target_link_libraries(cxx_shared PRIVATE $<TARGET_NAME_IF_EXISTS:cxxabi-reexports>)
   endif()
 
   # Generate a linker script in place of a libc++.so symlink.
   if (LIBCXX_ENABLE_ABI_LINKER_SCRIPT)