[runtimes] Always define the cxx_shared, cxx_static & other targets

[ldionne]

Summary

However, mark them as EXCLUDE_FROM_ALL when we don't want to build them.
Simply declaring the targets should be of no harm, and it allows other
projects to mention these targets regardless of whether they end up
being built or not.

While the diff may not make that obvious, this patch basically
moves the definition of e.g. cxx_shared out of the if (LIBCXX_ENABLE_SHARED)
and instead marks it as EXCLUDE_FROM_ALL conditionally on whether
LIBCXX_ENABLE_SHARED is passed. It then does the same for libunwind
and libc++abi targets.

[ldionne]

@daltenty I looked at the error in https://buildkite.com/llvm-project/libcxx-ci/builds/13649#01835770-a937-4a78-a82e-1dbe3add4e72 but I don't understand why there's a duplicate target producing libunwind.a. Could you please have a quick look? It doesn't reproduce when I use the AIX configuration locally on my mac.

[ldionne]

Rebase onto main.

[daltenty]

In D134221#3833280, @ldionne wrote:

@daltenty I looked at the error in https://buildkite.com/llvm-project/libcxx-ci/builds/13649#01835770-a937-4a78-a82e-1dbe3add4e72 but I don't understand why there's a duplicate target producing libunwind.a. Could you please have a quick look? It doesn't reproduce when I use the AIX configuration locally on my mac.

Ah, you've stumbled on some particular interestingness of CMake when it comes to AIX. AIX usually archives both shared libraries and static ones (one can actually mix the two in strange and interesting ways). Some versions of CMake on AIX implement this, so both the static and shared targets actually seem to come out with the same output names. We noticed this before but it worked ok for us in practice because we would configure for one or the other but not both.

Not sure what the best resolution is. Perhaps the easiest thing would be to modify the output names for the static libraries when on AIX to avoid the conflict? (though not sure how that effects test config and other usages)

[ldionne]

In D134221#3833443, @daltenty wrote:

In D134221#3833280, @ldionne wrote:

@daltenty I looked at the error in https://buildkite.com/llvm-project/libcxx-ci/builds/13649#01835770-a937-4a78-a82e-1dbe3add4e72 but I don't understand why there's a duplicate target producing libunwind.a. Could you please have a quick look? It doesn't reproduce when I use the AIX configuration locally on my mac.

Ah, you've stumbled on some particular interestingness of CMake when it comes to AIX. AIX usually archives both shared libraries and static ones (one can actually mix the two in strange and interesting ways). Some versions of CMake on AIX implement this, so both the static and shared targets actually seem to come out with the same output names. We noticed this before but it worked ok for us in practice because we would configure for one or the other but not both.

Do you mean that both unwind_shared and unwind_static both create a target named libunwind.a? Is there documentation for that CMake feature? I guess we could change the OUTPUT_NAME of the library, but that seems like kind of a hack.

[daltenty]

Do you mean that both unwind_shared and unwind_static both create a target named libunwind.a?

Yes, that's correct.

Is there documentation for that CMake feature?

Very regrettably, this is not a documented feature yet (though it's tracked by issue https://gitlab.kitware.com/cmake/cmake/-/issues/19494). The behaviour exists only in AIX packaged versions of CMake to my knowledge (though work is underway to upstream it).

I guess we could change the OUTPUT_NAME of the library, but that seems like kind of a hack.

Yes, I agree it is quite hackish. The AIX build is pretty reliant on being able to exclude the targets from the build at the moment though unfortunately, so if that is going away I'm afraid some sort of hackery will be required.

[ldionne]

In D134221#3833664, @daltenty wrote:

Yes, I agree it is quite hackish. The AIX build is pretty reliant on being able to exclude the targets from the build at the moment though unfortunately, so if that is going away I'm afraid some sort of hackery will be required.

Since we already support setting the OUTPUT_NAME of libc++.dylib, I went ahead with that solution in D135669. That way, the output name can be customized in AIX's CMake cache with a comment explaining why that's required.

Note that more generally speaking, I would expect this to cause a lot of issues on AIX with existing CMake projects (libc++/libunwind isn't special in any way here). IMO CMake may want to handle this problem somehow, but I'm not sure how.

[ldionne]

Rebase and address AIX issues.

@daltenty I already had this update ready to go before you created D135699, but let me know if you'd
rather go with yours instead, which is in a separate patch. I have no preference but I did find that
my comment explaining the issue was a bit more detailed.

[daltenty]

In D134221#3850412, @ldionne wrote:

Rebase and address AIX issues.

@daltenty I already had this update ready to go before you created D135699, but let me know if you'd
rather go with yours instead, which is in a separate patch. I have no preference but I did find that
my comment explaining the issue was a bit more detailed.

LGTM, thanks! I agree, let's go with this (I can adjust D135699 to include just adding the building of the static libraries)

[ldionne]

In D134221#3850643, @daltenty wrote:

In D134221#3850412, @ldionne wrote:

Rebase and address AIX issues.

@daltenty I already had this update ready to go before you created D135699, but let me know if you'd
rather go with yours instead, which is in a separate patch. I have no preference but I did find that
my comment explaining the issue was a bit more detailed.

LGTM, thanks! I agree, let's go with this (I can adjust D135699 to include just adding the building of the static libraries)

Do you actually have to build static libraries? IMO it's fine to just set their name to avoid conflicts but not necessarily build them if you don't need them.

[phosek]

All Fuchsia builders started failing after this change landed with the following error:

/b/s/w/ir/x/w/staging/llvm_build/./bin/clang++ --target=x86_64-unknown-fuchsia --sysroot=/b/s/w/ir/x/w/cipd/sdk/arch/x64/sysroot -fPIC --target=x86_64-unknown-fuchsia -I/b/s/w/ir/x/w/cipd/sdk/pkg/sync/include -I/b/s/w/ir/x/w/cipd/sdk/pkg/fdio/include -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -ffunction-sections -fdata-sections  -O3 -DNDEBUG  -L/b/s/w/ir/x/w/cipd/sdk/arch/x64/lib -Wl,-z,defs  -nostdlib++ -shared -Wl,-soname,libc++abi.so.1 -o lib/libc++abi.so.1.0 libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_aux_runtime.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_default_handlers.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_demangle.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_exception_storage.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_guard.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_handlers.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_vector.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_virtual.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/stdlib_exception.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/stdlib_stdexcept.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/stdlib_typeinfo.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/abort_message.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/fallback_malloc.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/private_typeinfo.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/stdlib_new_delete.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_noexception.cpp.obj libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_thread_atexit.cpp.obj  -lc  -lgcc  -lgcc_s && :
ld.lld: error: unable to find library -lgcc
ld.lld: error: unable to find library -lgcc_s

There's no libgcc on Fuchsia, we always use compiler-rt builtins so it's not clear to me why the build is now trying link libgcc when targeting Fuchsia after this change.

Would it be possible to revert this change while we investigate the issue?

[pcc]

TSan builds are also broken with this change: https://lab.llvm.org/buildbot/#/builders/70/builds/28491

ld: error: undefined symbol: __tsan_func_entry
>>> referenced by cxa_aux_runtime.cpp
>>>               libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_aux_runtime.cpp.o:(__cxa_bad_cast)
>>> referenced by cxa_aux_runtime.cpp
>>>               libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_aux_runtime.cpp.o:(__cxa_bad_typeid)
>>> referenced by cxa_aux_runtime.cpp
>>>               libcxxabi/src/CMakeFiles/cxxabi_shared_objects.dir/cxa_aux_runtime.cpp.o:(__cxa_throw_bad_array_new_length)
>>> referenced 539 more times

(and more undefined symbols).

[haowei]

I reverted this change in a3539090884c9159893c0b2b4c1dc34f23510707. Both Fuchsia bots and LLVM TSan bots failures indicates there is a regression caused by this change and need further investigation.

[ldionne]

@pcc @phosek

Can you please provide your respective minimal CMake invocations that reproduce that issue? I'll take a look.

[ldionne]

Reopen.

[pcc]

The sanitizer bot uses a 2-stage build so I'm not sure that it can be reproduced with a single CMake invocation. You should be able to reproduce on Linux with:

git clone https://github.com/llvm/llvm-zorg.git
BUILDBOT_CLOBBER= BUILDBOT_REVISION=79ee0342dbf025bc70f237bdfe9ccb4e10a592ce llvm-zorg/zorg/buildbot/builders/sanitizers/buildbot_standard.sh

[haowei]

In D134221#3853979, @ldionne wrote:

@pcc @phosek

Can you please provide your respective minimal CMake invocations that reproduce that issue? I'll take a look.

To setup Fuchsia's clang build you have to download some prebuilt including Fuchsia SDK, clang and sysroot. So it is not a straight forward 1 cmake invocation.
The builder task link is https://ci.chromium.org/ui/p/fuchsia/builders/toolchain.ci/clang-linux-x64/b8800503429662215329/overview and cmake command can be seen from step https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8800503429662215329/+/u/clang/configure/execution_details

libcxx/cmake/caches/AIX.cmake

 set(LIBCXX_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBCXX_ENABLE_STATIC OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC OFF CACHE BOOL "")
 set(LIBCXX_CXX_ABI libcxxabi CACHE STRING "")
 set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_SHARED ON CACHE BOOL "")
 set(LIBUNWIND_ENABLE_STATIC OFF CACHE BOOL "")
+
+# On AIX, both shared and static libraries are archived. As a result, both the static and the shared targets end
+# up with a `.a` suffix, which conflict. To workaround that, we set a different output name for the static
+# libraries, which we never actually build anyway. For more information, see https://gitlab.kitware.com/cmake/cmake/-/issues/19494.
+set(LIBCXX_STATIC_OUTPUT_NAME "c++-static" CACHE STRING "")
+set(LIBCXXABI_STATIC_OUTPUT_NAME "c++abi-static" CACHE STRING "")
+set(LIBUNWIND_STATIC_OUTPUT_NAME "unwind-static" CACHE STRING "")

libcxx/src/CMakeLists.txt

if (LIBCXX_CONFIGURE_IDE)
   endif()
   # Force them all into the headers dir on MSVC, otherwise they end up at
   # project scope because they don't have extensions.
   if (MSVC_IDE)
     source_group("Header Files" FILES ${LIBCXX_HEADERS})
   endif()
 endif()
 
-if(NOT LIBCXX_INSTALL_LIBRARY)
-  set(exclude_from_all EXCLUDE_FROM_ALL)
-endif()
-
 if (LIBCXX_GENERATE_COVERAGE AND NOT LIBCXX_COVERAGE_LIBRARY)
   find_compiler_rt_library(profile LIBCXX_COVERAGE_LIBRARY)
 endif()
 add_library_flags_if(LIBCXX_COVERAGE_LIBRARY "${LIBCXX_COVERAGE_LIBRARY}")
 
 if (APPLE AND LLVM_USE_SANITIZER)
   if (("${LLVM_USE_SANITIZER}" STREQUAL "Address") OR
       ("${LLVM_USE_SANITIZER}" STREQUAL "Address;Undefined") OR
function(cxx_set_common_defines name)
   if (LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
     target_link_libraries(${name} PUBLIC pstl::ParallelSTL)
   endif()
 endfunction()
 
 split_list(LIBCXX_COMPILE_FLAGS)
 split_list(LIBCXX_LINK_FLAGS)
 
+#
 # Build the shared library.
-if (LIBCXX_ENABLE_SHARED)
-  add_library(cxx_shared SHARED ${exclude_from_all} ${LIBCXX_SOURCES} ${LIBCXX_HEADERS})
-  target_include_directories(cxx_shared PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
-  target_link_libraries(cxx_shared PUBLIC cxx-headers
-                                   PRIVATE ${LIBCXX_LIBRARIES})
-  set_target_properties(cxx_shared
-    PROPERTIES
-      COMPILE_FLAGS "${LIBCXX_COMPILE_FLAGS}"
-      LINK_FLAGS    "${LIBCXX_LINK_FLAGS}"
-      OUTPUT_NAME   "${LIBCXX_SHARED_OUTPUT_NAME}"
-      VERSION       "${LIBCXX_LIBRARY_VERSION}"
-      SOVERSION     "${LIBCXX_ABI_VERSION}"
-      DEFINE_SYMBOL ""
-  )
-  cxx_add_common_build_flags(cxx_shared)
-  cxx_set_common_defines(cxx_shared)
+#
+add_library(cxx_shared SHARED $<$<NOT:$<BOOL:LIBCXX_ENABLE_SHARED>>:EXCLUDE_FROM_ALL> ${LIBCXX_SOURCES} ${LIBCXX_HEADERS})
 
-  if(ZOS)
-    add_custom_command(TARGET cxx_shared POST_BUILD
-      COMMAND
-        ${LIBCXX_SOURCE_DIR}/utils/zos_rename_dll_side_deck.sh
-        $<TARGET_LINKER_FILE_NAME:cxx_shared> $<TARGET_FILE_NAME:cxx_shared> "${LIBCXX_DLL_NAME}"
-      COMMENT "Rename dll name inside the side deck file"
-      WORKING_DIRECTORY $<TARGET_FILE_DIR:cxx_shared>
-    )
-  endif()
 
-  # Link against libc++abi
-  if (LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY)
-    target_link_libraries(cxx_shared PRIVATE libcxx-abi-shared-objects)
-  else()
-    target_link_libraries(cxx_shared PUBLIC libcxx-abi-shared)
-  endif()
 
-  # Maybe re-export symbols from libc++abi
-  # In particular, we don't re-export the symbols if libc++abi is merged statically
-  # into libc++ because in that case there's no dylib to re-export from.
-  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.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)
-    set(link_libraries)
 
-    set(imported_libname "$<TARGET_PROPERTY:libcxx-abi-shared,IMPORTED_LIBNAME>")
-    set(output_name "$<TARGET_PROPERTY:libcxx-abi-shared,OUTPUT_NAME>")
-    string(APPEND link_libraries "${CMAKE_LINK_LIBRARY_FLAG}$<IF:$<BOOL:${imported_libname}>,${imported_libname},${output_name}>")
 
-    # TODO: Move to the same approach as above for the unwind library
-    if (LIBCXXABI_USE_LLVM_UNWINDER)
-      if (LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_SHARED_LIBRARY)
-        # libunwind is already included in libc++abi
-      elseif (TARGET unwind_shared OR HAVE_LIBUNWIND)
-        string(APPEND link_libraries " ${CMAKE_LINK_LIBRARY_FLAG}$<TARGET_PROPERTY:unwind_shared,OUTPUT_NAME>")
-      else()
-        string(APPEND link_libraries " ${CMAKE_LINK_LIBRARY_FLAG}unwind")
-      endif()
-    endif()
 
-    set(linker_script "INPUT($<TARGET_SONAME_FILE_NAME:cxx_shared> ${link_libraries})")
-    add_custom_command(TARGET cxx_shared POST_BUILD
-      COMMAND "${CMAKE_COMMAND}" -E remove "$<TARGET_LINKER_FILE:cxx_shared>"
-      COMMAND "${CMAKE_COMMAND}" -E echo "${linker_script}" > "$<TARGET_LINKER_FILE:cxx_shared>"
-      COMMENT "Generating linker script: '${linker_script}' as file $<TARGET_LINKER_FILE:cxx_shared>"
-      VERBATIM
-    )
-  endif()
 
+if (LIBCXX_ENABLE_SHARED)
   list(APPEND LIBCXX_BUILD_TARGETS "cxx_shared")
-  if(WIN32 AND NOT MINGW AND NOT "${CMAKE_HOST_SYSTEM_NAME}" STREQUAL "Windows")
-    # Since we most likely do not have a mt.exe replacement, disable the
-    # manifest bundling.  This allows a normal cmake invocation to pass which
-    # will attempt to use the manifest tool to generate the bundled manifest
-    set_target_properties(cxx_shared PROPERTIES
-                          APPEND_STRING PROPERTY LINK_FLAGS " /MANIFEST:NO")
-  endif()
-endif()
+endif()
 
 set(CMAKE_STATIC_LIBRARY_PREFIX "lib")
 
+#
 # Build the static library.
-if (LIBCXX_ENABLE_STATIC)
-  add_library(cxx_static STATIC ${exclude_from_all} ${LIBCXX_SOURCES} ${LIBCXX_HEADERS})
-  target_include_directories(cxx_static PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
-  target_link_libraries(cxx_static PUBLIC cxx-headers
-                                   PRIVATE ${LIBCXX_LIBRARIES}
-                                   PRIVATE libcxx-abi-static)
-  set_target_properties(cxx_static
-    PROPERTIES
-      COMPILE_FLAGS "${LIBCXX_COMPILE_FLAGS}"
-      LINK_FLAGS    "${LIBCXX_LINK_FLAGS}"
-      OUTPUT_NAME   "${LIBCXX_STATIC_OUTPUT_NAME}"
-  )
-  cxx_add_common_build_flags(cxx_static)
-  cxx_set_common_defines(cxx_static)
+#
+add_library(cxx_static STATIC $<$<NOT:$<BOOL:LIBCXX_ENABLE_STATIC>>:EXCLUDE_FROM_ALL> ${LIBCXX_SOURCES} ${LIBCXX_HEADERS})
 
-  if (LIBCXX_HERMETIC_STATIC_LIBRARY)
-    # If the hermetic library doesn't define the operator new/delete functions
-    # then its code shouldn't declare them with hidden visibility.  They might
-    # actually be provided by a shared library at link time.
-    if (LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS)
-      append_flags_if_supported(CXX_STATIC_LIBRARY_FLAGS -fvisibility-global-new-delete-hidden)
-    endif()
-    target_compile_options(cxx_static PRIVATE ${CXX_STATIC_LIBRARY_FLAGS})
-    # _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS can be defined in __config_site
-    # too. Define it in the same way here, to avoid redefinition conflicts.
-    target_compile_definitions(cxx_static PRIVATE _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS=)
-  endif()
 
+if (LIBCXX_ENABLE_STATIC)
   list(APPEND LIBCXX_BUILD_TARGETS "cxx_static")
-  # Attempt to merge the libc++.a archive and the ABI library archive into one.
-  if (LIBCXX_STATICALLY_LINK_ABI_IN_STATIC_LIBRARY)
-    target_link_libraries(cxx_static PRIVATE libcxx-abi-static-objects)
-  endif()
-endif()
+endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(cxx DEPENDS ${LIBCXX_BUILD_TARGETS})
 
+#
+# Build the experimental static library
+#
 set(LIBCXX_EXPERIMENTAL_SOURCES
   experimental/memory_resource.cpp
   format.cpp
   )
 
 add_library(cxx_experimental STATIC ${LIBCXX_EXPERIMENTAL_SOURCES})
 target_link_libraries(cxx_experimental PUBLIC cxx-headers)
 if (LIBCXX_ENABLE_SHARED)

libcxxabi/src/CMakeLists.txt

PROPERTIES
     CXX_STANDARD_REQUIRED OFF
     COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}"
     DEFINE_SYMBOL ""
 )
 if (CMAKE_POSITION_INDEPENDENT_CODE OR NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
   set_target_properties(cxxabi_shared_objects PROPERTIES POSITION_INDEPENDENT_CODE ON) # must set manually because it's an object library
 endif()
 
-if (LIBCXXABI_ENABLE_SHARED)
-  add_library(cxxabi_shared SHARED)
-  set_target_properties(cxxabi_shared
-    PROPERTIES
-      LINK_FLAGS "${LIBCXXABI_LINK_FLAGS}"
-      OUTPUT_NAME "${LIBCXXABI_SHARED_OUTPUT_NAME}"
-      SOVERSION "1"
-      VERSION "${LIBCXXABI_LIBRARY_VERSION}"
-  )
+add_library(cxxabi_shared SHARED $<$<NOT:$<BOOL:LIBCXXABI_ENABLE_SHARED>>:EXCLUDE_FROM_ALL>)
 
-  if (ZOS)
-    add_custom_command(TARGET cxxabi_shared POST_BUILD
-      COMMAND
-        ${LIBCXXABI_LIBCXX_PATH}/utils/zos_rename_dll_side_deck.sh
-        $<TARGET_LINKER_FILE_NAME:cxxabi_shared> $<TARGET_FILE_NAME:cxxabi_shared> "${LIBCXXABI_DLL_NAME}"
-      COMMENT "Rename dll name inside the side deck file"
-      WORKING_DIRECTORY $<TARGET_FILE_DIR:cxxabi_shared>
-    )
-  endif ()
 
-  target_link_libraries(cxxabi_shared
-    PUBLIC cxxabi_shared_objects
-    PRIVATE ${LIBCXXABI_SHARED_LIBRARIES} ${LIBCXXABI_LIBRARIES})
-  if (TARGET pstl::ParallelSTL)
-    target_link_libraries(cxxabi_shared PUBLIC pstl::ParallelSTL)
-  endif()
 
+if (LIBCXXABI_ENABLE_SHARED)
   list(APPEND LIBCXXABI_BUILD_TARGETS "cxxabi_shared")
-  if (LIBCXXABI_INSTALL_SHARED_LIBRARY)
-    list(APPEND LIBCXXABI_INSTALL_TARGETS "cxxabi_shared")
-  endif()
+endif()
 
-  add_library(cxxabi-reexports INTERFACE)
-
-  # -exported_symbols_list is only available on Apple platforms
-  if (APPLE)
-    function(export_symbols file)
-      target_link_libraries(cxxabi_shared PRIVATE "-Wl,-exported_symbols_list,${file}")
-    endfunction()
-    function(reexport_symbols file)
-      export_symbols("${file}")
-      target_link_libraries(cxxabi-reexports INTERFACE "-Wl,-reexported_symbols_list,${file}")
-    endfunction()
 
-    export_symbols("${CMAKE_CURRENT_SOURCE_DIR}/../lib/itanium-base.exp")
 
-    if (LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS)
-      reexport_symbols("${CMAKE_CURRENT_SOURCE_DIR}/../lib/new-delete.exp")
-    endif()
 
-    if (LIBCXXABI_ENABLE_EXCEPTIONS)
-      reexport_symbols("${CMAKE_CURRENT_SOURCE_DIR}/../lib/exceptions.exp")
 
-      if ("${CMAKE_OSX_ARCHITECTURES}" MATCHES "^(armv6|armv7|armv7s)$")
-        reexport_symbols("${CMAKE_CURRENT_SOURCE_DIR}/../lib/personality-sjlj.exp")
-      else()
-        reexport_symbols("${CMAKE_CURRENT_SOURCE_DIR}/../lib/personality-v0.exp")
-      endif()
-    endif()
-  endif()
-endif()
 
 # Build the static library.
 add_library(cxxabi_static_objects OBJECT EXCLUDE_FROM_ALL ${LIBCXXABI_SOURCES} ${LIBCXXABI_HEADERS})
 if (LIBCXXABI_USE_LLVM_UNWINDER AND LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY)
   target_link_libraries(cxxabi_static_objects PUBLIC unwind_static_objects) # propagate usage requirements
   target_sources(cxxabi_static_objects PUBLIC $<TARGET_OBJECTS:unwind_static_objects>)
 endif()
 target_link_libraries(cxxabi_static_objects PRIVATE cxx-headers ${LIBCXXABI_STATIC_LIBRARIES} ${LIBCXXABI_LIBRARIES})
if(LIBCXXABI_HERMETIC_STATIC_LIBRARY)
   # __config_site too. Define it in the same way here, to avoid redefinition
   # conflicts.
   target_compile_definitions(cxxabi_static_objects
     PRIVATE
       _LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS
       _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS=)
 endif()
 
-if (LIBCXXABI_ENABLE_STATIC)
-  add_library(cxxabi_static STATIC)
-  if (LIBCXXABI_USE_LLVM_UNWINDER AND NOT LIBCXXABI_STATICALLY_LINK_UNWINDER_IN_STATIC_LIBRARY)
-    target_link_libraries(cxxabi_static PUBLIC unwind_static)
-  endif()
-  set_target_properties(cxxabi_static
-    PROPERTIES
-      LINK_FLAGS "${LIBCXXABI_LINK_FLAGS}"
-      OUTPUT_NAME "${LIBCXXABI_STATIC_OUTPUT_NAME}"
-    )
-  target_link_libraries(cxxabi_static
-    PUBLIC cxxabi_static_objects
-    PRIVATE ${LIBCXXABI_STATIC_LIBRARIES} ${LIBCXXABI_LIBRARIES})
-  if (TARGET pstl::ParallelSTL)
-    target_link_libraries(cxxabi_static PUBLIC pstl::ParallelSTL)
-  endif()
+add_library(cxxabi_static STATIC $<$<NOT:$<BOOL:LIBCXXABI_ENABLE_STATIC>>:EXCLUDE_FROM_ALL>)
 
+if (LIBCXXABI_ENABLE_STATIC)
   list(APPEND LIBCXXABI_BUILD_TARGETS "cxxabi_static")
-  if (LIBCXXABI_INSTALL_STATIC_LIBRARY)
-    list(APPEND LIBCXXABI_INSTALL_TARGETS "cxxabi_static")
-  endif()
-endif()
+endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(cxxabi DEPENDS ${LIBCXXABI_BUILD_TARGETS})
 
 if (LIBCXXABI_INSTALL_LIBRARY)
   install(TARGETS ${LIBCXXABI_INSTALL_TARGETS}
     LIBRARY DESTINATION ${LIBCXXABI_INSTALL_LIBRARY_DIR} COMPONENT cxxabi
     ARCHIVE DESTINATION ${LIBCXXABI_INSTALL_LIBRARY_DIR} COMPONENT cxxabi

libunwind/src/CMakeLists.txt

set_property(SOURCE ${LIBUNWIND_CXX_SOURCES}
              APPEND_STRING PROPERTY COMPILE_FLAGS " ${LIBUNWIND_CXX_FLAGS}")
 set_property(SOURCE ${LIBUNWIND_C_SOURCES}
              APPEND_STRING PROPERTY COMPILE_FLAGS " ${LIBUNWIND_C_FLAGS}")
 
 # NOTE: avoid implicit dependencies on C++ runtimes.  libunwind uses C++ for
 # ease, but does not rely on C++ at runtime.
 set(CMAKE_CXX_IMPLICIT_LINK_LIBRARIES "")
 
+#
 # Build the shared library.
+#
 add_library(unwind_shared_objects OBJECT EXCLUDE_FROM_ALL ${LIBUNWIND_SOURCES} ${LIBUNWIND_HEADERS})
 if(CMAKE_C_COMPILER_ID STREQUAL MSVC)
   target_compile_options(unwind_shared_objects PRIVATE /GR-)
 else()
   target_compile_options(unwind_shared_objects PRIVATE -fno-rtti)
 endif()
 target_link_libraries(unwind_shared_objects PRIVATE unwind-headers ${LIBUNWIND_LIBRARIES})
 set_target_properties(unwind_shared_objects
   PROPERTIES
     CXX_EXTENSIONS OFF
     CXX_STANDARD 11
     CXX_STANDARD_REQUIRED ON
     COMPILE_FLAGS "${LIBUNWIND_COMPILE_FLAGS}"
 )
 if (CMAKE_POSITION_INDEPENDENT_CODE OR NOT DEFINED CMAKE_POSITION_INDEPENDENT_CODE)
   set_target_properties(unwind_shared_objects PROPERTIES POSITION_INDEPENDENT_CODE ON) # must set manually because it's an object library
 endif()
 
-if (LIBUNWIND_ENABLE_SHARED)
-  add_library(unwind_shared SHARED)
-  target_link_libraries(unwind_shared PUBLIC unwind_shared_objects)
-  set_target_properties(unwind_shared
-    PROPERTIES
-      LINK_FLAGS "${LIBUNWIND_LINK_FLAGS}"
-      LINKER_LANGUAGE C
-      OUTPUT_NAME "${LIBUNWIND_SHARED_OUTPUT_NAME}"
-      VERSION "1.0"
-      SOVERSION "1"
-  )
+add_library(unwind_shared SHARED $<$<NOT:$<BOOL:LIBUNWIND_ENABLE_SHARED>>:EXCLUDE_FROM_ALL>)
 
+if (LIBUNWIND_ENABLE_SHARED)
   list(APPEND LIBUNWIND_BUILD_TARGETS "unwind_shared")
-  if (LIBUNWIND_INSTALL_SHARED_LIBRARY)
-    list(APPEND LIBUNWIND_INSTALL_TARGETS "unwind_shared")
-  endif()
-endif()
+endif()
 
+#
 # Build the static library.
+#
 add_library(unwind_static_objects OBJECT EXCLUDE_FROM_ALL ${LIBUNWIND_SOURCES} ${LIBUNWIND_HEADERS})
 if(CMAKE_C_COMPILER_ID STREQUAL MSVC)
   target_compile_options(unwind_static_objects PRIVATE /GR-)
 else()
   target_compile_options(unwind_static_objects PRIVATE -fno-rtti)
 endif()
 target_link_libraries(unwind_static_objects PRIVATE unwind-headers ${LIBUNWIND_LIBRARIES})
 set_target_properties(unwind_static_objects
   PROPERTIES
     CXX_EXTENSIONS OFF
     CXX_STANDARD 11
     CXX_STANDARD_REQUIRED ON
     COMPILE_FLAGS "${LIBUNWIND_COMPILE_FLAGS}"
 )
 
 if(LIBUNWIND_HIDE_SYMBOLS)
   target_add_compile_flags_if_supported(unwind_static_objects PRIVATE -fvisibility=hidden)
   target_add_compile_flags_if_supported(unwind_static_objects PRIVATE -fvisibility-global-new-delete-hidden)
   target_compile_definitions(unwind_static_objects PRIVATE _LIBUNWIND_HIDE_SYMBOLS)
 endif()
 
-if (LIBUNWIND_ENABLE_STATIC)
-  add_library(unwind_static STATIC)
-  target_link_libraries(unwind_static PUBLIC unwind_static_objects)
-  set_target_properties(unwind_static
-    PROPERTIES
-      LINK_FLAGS "${LIBUNWIND_LINK_FLAGS}"
-      LINKER_LANGUAGE C
-      OUTPUT_NAME "${LIBUNWIND_STATIC_OUTPUT_NAME}"
-  )
+add_library(unwind_static STATIC $<$<NOT:$<BOOL:LIBUNWIND_ENABLE_STATIC>>:EXCLUDE_FROM_ALL>)
 
+if (LIBUNWIND_ENABLE_STATIC)
   list(APPEND LIBUNWIND_BUILD_TARGETS "unwind_static")
-  if (LIBUNWIND_INSTALL_STATIC_LIBRARY)
-    list(APPEND LIBUNWIND_INSTALL_TARGETS "unwind_static")
-  endif()
-endif()
+endif()
 
 # Add a meta-target for both libraries.
 add_custom_target(unwind DEPENDS ${LIBUNWIND_BUILD_TARGETS})
 
 if (LIBUNWIND_INSTALL_LIBRARY)
   install(TARGETS ${LIBUNWIND_INSTALL_TARGETS}
     LIBRARY DESTINATION ${LIBUNWIND_INSTALL_LIBRARY_DIR} COMPONENT unwind
     ARCHIVE DESTINATION ${LIBUNWIND_INSTALL_LIBRARY_DIR} COMPONENT unwind