[libcxxabi] rework CMakeLists.txt into modules

[martell]

Summary

libcxxabi was having issues with detecting flags in config-ix.cmakecorrectly when cross compiling.
I narrowed it down to changes as a result of including

list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
include("${LLVM_CMAKE_PATH}/AddLLVM.cmake")
include("${LLVM_CMAKE_PATH}/HandleLLVMOptions.cmake")

The best way to solve this was to rework CMake to use modules to mirror libcxx.
This makes the cmake source more readable and maintainable

[martell]

removed needless check and update comment

[martell]

Added CMAKE_RUNTIME_OUTPUT_DIRECTORY like libcxx

[martell]

remove unnecessary cmake policy

[martell]

Sorry about the bumps with small changes.
Should be in good shape now.
Please Review.

CMakeLists.txt

325

Just a note here. This doesn't do anything since rL288692 so removing it here.
I have put together a patch to enable different options for static and shared builds when they are both requested in the one cmake run so I will add that in a follow up differential.

[martell]

CMakeLists.txt

325

I fixed this in rL304110.
Will update without removing this block for now to make this commit cleaner

[martell]

rebased to master and refined commit to only change what it is intended to do

[EricWF]

This is supposed to be NFC, right? If so it LGTM. @martell Do you have commit access or should I commit this for you?

[martell]

@EricWF What does NFC mean?
I have commit access :)

[EricWF]

NFC == No functionality change.

This patch just re-factors the CMake stuff without adding or removing anything at the same time, right?

[martell]

Thanks for explaining the acronym.
With respect to the project itself yes there is NFC but it does change the cmake functionality which fixes a few bugs because we do not depend on LLVM cmake modules anymore.

[EricWF]

With respect to the project itself yes there is NFC but it does change the cmake functionality which fixes a few bugs because we do not depend on LLVM cmake modules anymore.

I'm not sure what this means? What modules do we no longer depend on?

[martell]

@EricWF The HandleLLVMOptions.cmake module is no longer loaded

[EricWF]

Urg... so all of the configuration done in that file is no longer handled?!? That's the opposite of a change that has no effect on functionality...

[martell]

In D33635#769577, @EricWF wrote:

Urg... so all of the configuration done in that file is no longer handled?!? That's the opposite of a change that has no effect on functionality...

Correct. I would note however that libc++ does not depend on that module either.
I believe keeping libc++abi consistent with libc++ makes sense here.
Unless someone wants to reintroduce that dependency into libc++?

[EricWF]

In D33635#769583, @martell wrote:

In D33635#769577, @EricWF wrote:

Urg... so all of the configuration done in that file is no longer handled?!? That's the opposite of a change that has no effect on functionality...

Correct. I would note however that libc++ does not depend on that module either.
I believe keeping libc++abi consistent with libc++ makes sense here.
Unless someone wants to reintroduce that dependency into libc++?

Libc++ also has some other configuration changes to make that work, like handling LLVM_USE_SANITIZER, which libc++abi doesn't right now but did before...

[martell]

! In D33635#769584, @EricWF wrote:
Libc++ also has some other configuration changes to make that work, like handling LLVM_USE_SANITIZER, which libc++abi doesn't right now but did before...

Ahh I see, In that case we could add include(HandleLLVMOptions OPTIONAL) below include(AddLLVM OPTIONAL) in HandleOutOfTreeLLVM.cmake
I can either then re-evaluate why I have issues in cross compiling and either migrate the LLVM_USE_SANITIZER code to libcxxabi later or fix in another way.

[martell]

I would note however that I haven't gotten a buildbot error from this change.
Is the sanitizer actually tested with libc++abi?

[martell]

Ignore my previous comment, I misread your note about it not needing it anymore.

[EricWF]

In D33635#769591, @martell wrote:

Ignore my previous comment, I misread your note about it not needing it anymore.

I didn't intend to say it wasn't needed anymore. It's still needed for out-of-tree builds.

[martell]

I created D33753 to re add that support.
If you can approve I will push it on top.
Thanks for the feedback btw.

CMakeLists.txt

+# See www/CMake.html for instructions on how to build libcxxabi with CMake.
+
 #===============================================================================
 # Setup Project
 #===============================================================================

   )
 
 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
-  project(libcxxabi)
-
-  # Rely on llvm-config.
-  set(CONFIG_OUTPUT)
-  if (NOT LLVM_CONFIG_PATH)
-    find_program(LLVM_CONFIG_PATH "llvm-config")
-  endif()
-  if(DEFINED LLVM_PATH)
-    set(LLVM_INCLUDE_DIR ${LLVM_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
-    set(LLVM_PATH ${LLVM_PATH} CACHE PATH "Path to LLVM source tree")
-    set(LLVM_MAIN_SRC_DIR ${LLVM_PATH})
-    set(LLVM_CMAKE_PATH "${LLVM_PATH}/cmake/modules")
-  elseif(LLVM_CONFIG_PATH)
-    message(STATUS "Found LLVM_CONFIG_PATH as ${LLVM_CONFIG_PATH}")
-    set(CONFIG_COMMAND ${LLVM_CONFIG_PATH}
-      "--includedir"
-      "--prefix"
-      "--src-root")
-    execute_process(
-      COMMAND ${CONFIG_COMMAND}
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE CONFIG_OUTPUT
-    )
-    if(NOT HAD_ERROR)
-      string(REGEX REPLACE
-        "[ \t]*[\r\n]+[ \t]*" ";"
-        CONFIG_OUTPUT ${CONFIG_OUTPUT})
-    else()
-      string(REPLACE ";" " " CONFIG_COMMAND_STR "${CONFIG_COMMAND}")
-      message(STATUS "${CONFIG_COMMAND_STR}")
-      message(FATAL_ERROR "llvm-config failed with status ${HAD_ERROR}")
-    endif()
-
-    list(GET CONFIG_OUTPUT 0 INCLUDE_DIR)
-    list(GET CONFIG_OUTPUT 1 LLVM_OBJ_ROOT)
-    list(GET CONFIG_OUTPUT 2 MAIN_SRC_DIR)
-
-    set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
-    set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
-    set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
-    set(LLVM_LIT_PATH "${LLVM_PATH}/utils/lit/lit.py")
-
-    # --cmakedir is supported since llvm r291218 (4.0 release)
-    execute_process(
-      COMMAND ${LLVM_CONFIG_PATH} --cmakedir
-      RESULT_VARIABLE HAD_ERROR
-      OUTPUT_VARIABLE CONFIG_OUTPUT
-      ERROR_QUIET)
-    if(NOT HAD_ERROR)
-      string(STRIP "${CONFIG_OUTPUT}" LLVM_CMAKE_PATH)
-    else()
-      set(LLVM_CMAKE_PATH
-          "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
-    endif()
-  else()
-    message(FATAL_ERROR "llvm-config not found and LLVM_MAIN_SRC_DIR not defined. "
-                        "Reconfigure with -DLLVM_CONFIG_PATH=path/to/llvm-config "
-                        "or -DLLVM_PATH=path/to/llvm-source-root.")
-  endif()
-
-  if(EXISTS ${LLVM_CMAKE_PATH})
-    list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
-    include("${LLVM_CMAKE_PATH}/AddLLVM.cmake")
-    include("${LLVM_CMAKE_PATH}/HandleLLVMOptions.cmake")
-  else()
-    message(FATAL_ERROR "Not found: ${LLVM_CMAKE_PATH}")
-  endif()
+  project(libcxxabi CXX C)
 
   set(PACKAGE_NAME libcxxabi)
   set(PACKAGE_VERSION 5.0.0svn)
   set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}")
   set(PACKAGE_BUGREPORT "[e-mail]")
 
-  if (NOT DEFINED LLVM_INCLUDE_TESTS)
-    set(LLVM_INCLUDE_TESTS ON)
-  endif()
-
-  if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-    set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-  else()
-    # Seek installed Lit.
-    find_program(LLVM_LIT "lit.py" ${LLVM_MAIN_SRC_DIR}/utils/lit
-      DOC "Path to lit.py")
-  endif()
-
-  if(LLVM_LIT)
-    # Define the default arguments to use with 'lit', and an option for the user
-    # to override.
-    set(LIT_ARGS_DEFAULT "-sv")
-    if (MSVC OR XCODE)
-      set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
-    endif()
-    set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
-
-    # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
-    if( WIN32 AND NOT CYGWIN )
-      set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
-    endif()
-  else()
-    set(LLVM_INCLUDE_TESTS OFF)
-  endif()
-
-  set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
-      "Define suffix of library directory name (32/64)")
-
-  set(LIBCXXABI_STANDALONE_BUILD 1)
-else()
-  set(LLVM_MAIN_SRC_DIR "${CMAKE_SOURCE_DIR}" CACHE PATH "Path to LLVM source tree")
-  set(LLVM_LIT "${CMAKE_SOURCE_DIR}/utils/lit/lit.py")
-  set(LIBCXXABI_LIBDIR_SUFFIX ${LLVM_LIBDIR_SUFFIX})
+  # Find the LLVM sources and simulate LLVM CMake options.
+  include(HandleOutOfTreeLLVM)
 endif()
 
+# Require out of source build.
+include(MacroEnsureOutOfSourceBuild)
+MACRO_ENSURE_OUT_OF_SOURCE_BUILD(
+ "${PROJECT_NAME} requires an out of source build. Please create a separate
+ build directory and run 'cmake /path/to/${PROJECT_NAME} [options]' there."
+ )
+
 #===============================================================================
 # Setup CMake Options
 #===============================================================================
+include(CMakeDependentOption)
 include(HandleCompilerRT)
 
 # Define options.

 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 
 # By default, for non-standalone builds, libcxx and libcxxabi share a library
 # directory.

   message(FATAL_ERROR "LIBCXXABI_BUILD_32_BITS=ON is not supported on this platform.")
 endif()
 
-#===============================================================================
-# Setup Compiler Flags
-#===============================================================================
-
-# Get required flags.
-macro(append_if list condition var)
-  if (${condition})
-    list(APPEND ${list} ${var})
-  endif()
-endmacro()
-
-macro(add_target_flags_if condition var)
-  if (${condition})
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${var}")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${var}")
-    list(APPEND LIBCXXABI_COMPILE_FLAGS ${var})
-    list(APPEND LIBCXXABI_LINK_FLAGS ${var})
-  endif()
-endmacro()
+# Declare libc++abi configuration variables.
+# They are intended for use as follows:
+# LIBCXXABI_C_FLAGS: General flags for both the c++ compiler and linker.
+# LIBCXXABI_CXX_FLAGS: General flags for both the c++ compiler and linker.
+# LIBCXXABI_COMPILE_FLAGS: Compile only flags.
+# LIBCXXABI_LINK_FLAGS: Linker only flags.
+# LIBCXXABI_LIBRARIES: libraries libc++abi is linked to.
 
 set(LIBCXXABI_C_FLAGS "")
 set(LIBCXXABI_CXX_FLAGS "")
 set(LIBCXXABI_COMPILE_FLAGS "")
 set(LIBCXXABI_LINK_FLAGS "")
+set(LIBCXXABI_LIBRARIES "")
+
+# Include macros for adding and removing libc++abi flags.
+include(HandleLibcxxabiFlags)
+
+#===============================================================================
+# Setup Compiler Flags
+#===============================================================================
 
 # Configure target flags
 add_target_flags_if(LIBCXXABI_BUILD_32_BITS "-m32")

   string(REPLACE "-stdlib=libstdc++" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 endif()
 
-if (LIBCXXABI_USE_COMPILER_RT)
-  list(APPEND LIBCXXABI_LINK_FLAGS "-rtlib=compiler-rt")
-endif()
-
 # Let the library headers know they are currently being used to build the
 # library.
 add_definitions(-D_LIBCXXABI_BUILDING_LIBRARY)
 
-# Disable DLL annotations on Windows for static builds.
-if (WIN32 AND LIBCXXABI_ENABLE_STATIC AND NOT LIBCXXABI_ENABLE_SHARED)
-  add_definitions(-D_LIBCXXABI_DISABLE_DLL_IMPORT_EXPORT)
-endif()
-
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WERROR_FLAG -Werror=return-type)
+add_compile_flags_if_supported(-Werror=return-type)
 
 # Get warning flags
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_W_FLAG -W)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WALL_FLAG -Wall)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WCHAR_SUBSCRIPTS_FLAG -Wchar-subscripts)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WCONVERSION_FLAG -Wconversion)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WMISMATCHED_TAGS_FLAG -Wmismatched-tags)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WMISSING_BRACES_FLAG -Wmissing-braces)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WNEWLINE_EOF_FLAG -Wnewline-eof)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNUSED_FUNCTION_FLAG -Wunused-function)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSHADOW_FLAG -Wshadow)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSHORTEN_64_TO_32_FLAG -Wshorten-64-to-32)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSIGN_COMPARE_FLAG -Wsign-compare)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSIGN_CONVERSION_FLAG -Wsign-conversion)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSTRICT_ALIASING_FLAG -Wstrict-aliasing=2)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WSTRICT_OVERFLOW_FLAG -Wstrict-overflow=4)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNUSED_PARAMETER_FLAG -Wunused-parameter)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNUSED_VARIABLE_FLAG -Wunused-variable)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WWRITE_STRINGS_FLAG -Wwrite-strings)
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WUNDEF_FLAG -Wundef)
+add_compile_flags_if_supported(-W)
+add_compile_flags_if_supported(-Wall)
+add_compile_flags_if_supported(-Wchar-subscripts)
+add_compile_flags_if_supported(-Wconversion)
+add_compile_flags_if_supported(-Wmismatched-tags)
+add_compile_flags_if_supported(-Wmissing-braces)
+add_compile_flags_if_supported(-Wnewline-eof)
+add_compile_flags_if_supported(-Wunused-function)
+add_compile_flags_if_supported(-Wshadow)
+add_compile_flags_if_supported(-Wshorten-64-to-32)
+add_compile_flags_if_supported(-Wsign-compare)
+add_compile_flags_if_supported(-Wsign-conversion)
+add_compile_flags_if_supported(-Wstrict-aliasing=2)
+add_compile_flags_if_supported(-Wstrict-overflow=4)
+add_compile_flags_if_supported(-Wunused-parameter)
+add_compile_flags_if_supported(-Wunused-variable)
+add_compile_flags_if_supported(-Wwrite-strings)
+add_compile_flags_if_supported(-Wundef)
 
 if (LIBCXXABI_ENABLE_WERROR)
-  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WERROR_FLAG -Werror)
-  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WX_FLAG -WX)
+  add_compile_flags_if_supported(-Werror)
+  add_compile_flags_if_supported(-WX)
 else()
-  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_WNO_ERROR_FLAG -Wno-error)
-  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_NO_WX_FLAG -WX-)
+  add_compile_flags_if_supported(-Wno-error)
+  add_compile_flags_if_supported(-WX-)
 endif()
 if (LIBCXXABI_ENABLE_PEDANTIC)
-  append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_PEDANTIC_FLAG -pedantic)
+  add_compile_flags_if_supported(-pedantic)
 endif()
 
 # Get feature flags.
-append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_FSTRICT_ALIASING_FLAG -fstrict-aliasing)
+add_compile_flags_if_supported(-fstrict-aliasing)
 
 # Exceptions
 if (LIBCXXABI_ENABLE_EXCEPTIONS)
   # Catches C++ exceptions only and tells the compiler to assume that extern C
   # functions never throw a C++ exception.
-  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_EHSC_FLAG -EHsc)
-  append_if(LIBCXXABI_C_FLAGS LIBCXXABI_HAS_FUNWIND_TABLES -funwind-tables)
+  add_compile_flags_if_supported(-EHsc)
+  # Do we really need to be run through the C compiler ?
+  add_c_compile_flags_if_supported(-funwind-tables)
 else()
   add_definitions(-D_LIBCXXABI_NO_EXCEPTIONS)
-  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EXCEPTIONS_FLAG -fno-exceptions)
-  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EHS_FLAG -EHs-)
-  append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_NO_EHA_FLAG -EHa-)
+  add_compile_flags_if_supported(-fno-exceptions)
+  add_compile_flags_if_supported(-EHs-)
+  add_compile_flags_if_supported(-EHa-)
 endif()
 
 # Assert

cmake/Modules/HandleLibcxxabiFlags.cmake

+# HandleLibcxxFlags - A set of macros used to setup the flags used to compile
+# and link libc++. These macros add flags to the following CMake variables.
+# - LIBCXXABI_COMPILE_FLAGS: flags used to compile libc++
+# - LIBCXXABI_LINK_FLAGS: flags used to link libc++
+# - LIBCXXABI_LIBRARIES: libraries to link libc++ to.
+
+include(CheckCXXCompilerFlag)
+
+unset(add_flag_if_supported)
+
+# Mangle the name of a compiler flag into a valid CMake identifier.
+# Ex: --std=c++11 -> STD_EQ_CXX11
+macro(mangle_name str output)
+  string(STRIP "${str}" strippedStr)
+  string(REGEX REPLACE "^/" "" strippedStr "${strippedStr}")
+  string(REGEX REPLACE "^-+" "" strippedStr "${strippedStr}")
+  string(REGEX REPLACE "-+$" "" strippedStr "${strippedStr}")
+  string(REPLACE "-" "_" strippedStr "${strippedStr}")
+  string(REPLACE "=" "_EQ_" strippedStr "${strippedStr}")
+  string(REPLACE "+" "X" strippedStr "${strippedStr}")
+  string(TOUPPER "${strippedStr}" ${output})
+endmacro()
+
+# Remove a list of flags from all CMake variables that affect compile flags.
+# This can be used to remove unwanted flags specified on the command line
+# or added in other parts of LLVM's cmake configuration.
+macro(remove_flags)
+  foreach(var ${ARGN})
+    string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG}")
+    string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL}")
+    string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE}")
+    string(REPLACE "${var}" "" CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
+    string(REPLACE "${var}" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+    string(REPLACE "${var}" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+    string(REPLACE "${var}" "" CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}")
+    string(REPLACE "${var}" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
+    string(REPLACE "${var}" "" CMAKE_SHARED_MODULE_FLAGS "${CMAKE_SHARED_MODULE_FLAGS}")
+    remove_definitions(${var})
+  endforeach()
+endmacro(remove_flags)
+
+macro(check_flag_supported flag)
+    mangle_name("${flag}" flagname)
+    check_cxx_compiler_flag("${flag}" "LIBCXXABI_SUPPORTS_${flagname}_FLAG")
+endmacro()
+
+# Add a macro definition if condition is true.
+macro(define_if condition def)
+  if (${condition})
+    add_definitions(${def})
+  endif()
+endmacro()
+
+# Add a macro definition if condition is not true.
+macro(define_if_not condition def)
+  if (NOT ${condition})
+    add_definitions(${def})
+  endif()
+endmacro()
+
+# Add a macro definition to the __config_site file if the specified condition
+# is 'true'. Note that '-D${def}' is not added. Instead it is expected that
+# the build include the '__config_site' header.
+macro(config_define_if condition def)
+  if (${condition})
+    set(${def} ON)
+    set(LIBCXXABI_NEEDS_SITE_CONFIG ON)
+  endif()
+endmacro()
+
+macro(config_define_if_not condition def)
+  if (NOT ${condition})
+    set(${def} ON)
+    set(LIBCXXABI_NEEDS_SITE_CONFIG ON)
+  endif()
+endmacro()
+
+macro(config_define value def)
+  set(${def} ${value})
+  set(LIBCXXABI_NEEDS_SITE_CONFIG ON)
+endmacro()
+
+# Add a list of flags to all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS',
+# 'LIBCXXABI_COMPILE_FLAGS' and 'LIBCXXABI_LINK_FLAGS'.
+macro(add_target_flags)
+  foreach(value ${ARGN})
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${value}")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${value}")
+    list(APPEND LIBCXXABI_COMPILE_FLAGS ${value})
+    list(APPEND LIBCXXABI_LINK_FLAGS ${value})
+  endforeach()
+endmacro()
+
+# If the specified 'condition' is true then add a list of flags to
+# all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS', 'LIBCXXABI_COMPILE_FLAGS'
+# and 'LIBCXXABI_LINK_FLAGS'.
+macro(add_target_flags_if condition)
+  if (${condition})
+    add_target_flags(${ARGN})
+  endif()
+endmacro()
+
+# Add a specified list of flags to both 'LIBCXXABI_COMPILE_FLAGS' and
+# 'LIBCXXABI_LINK_FLAGS'.
+macro(add_flags)
+  foreach(value ${ARGN})
+    list(APPEND LIBCXXABI_COMPILE_FLAGS ${value})
+    list(APPEND LIBCXXABI_LINK_FLAGS ${value})
+  endforeach()
+endmacro()
+
+# If the specified 'condition' is true then add a list of flags to both
+# 'LIBCXXABI_COMPILE_FLAGS' and 'LIBCXXABI_LINK_FLAGS'.
+macro(add_flags_if condition)
+  if (${condition})
+    add_flags(${ARGN})
+  endif()
+endmacro()
+
+# Add each flag in the list to LIBCXXABI_COMPILE_FLAGS and LIBCXXABI_LINK_FLAGS
+# if that flag is supported by the current compiler.
+macro(add_flags_if_supported)
+  foreach(flag ${ARGN})
+      mangle_name("${flag}" flagname)
+      check_cxx_compiler_flag("${flag}" "LIBCXXABI_SUPPORTS_${flagname}_FLAG")
+      add_flags_if(LIBCXXABI_SUPPORTS_${flagname}_FLAG ${flag})
+  endforeach()
+endmacro()
+
+# Add a list of flags to 'LIBCXXABI_COMPILE_FLAGS'.
+macro(add_compile_flags)
+  foreach(f ${ARGN})
+    list(APPEND LIBCXXABI_COMPILE_FLAGS ${f})
+  endforeach()
+endmacro()
+
+# If 'condition' is true then add the specified list of flags to
+# 'LIBCXXABI_COMPILE_FLAGS'
+macro(add_compile_flags_if condition)
+  if (${condition})
+    add_compile_flags(${ARGN})
+  endif()
+endmacro()
+
+# For each specified flag, add that flag to 'LIBCXXABI_COMPILE_FLAGS' if the
+# flag is supported by the C++ compiler.
+macro(add_compile_flags_if_supported)
+  foreach(flag ${ARGN})
+      mangle_name("${flag}" flagname)
+      check_cxx_compiler_flag("${flag}" "LIBCXXABI_SUPPORTS_${flagname}_FLAG")
+      add_compile_flags_if(LIBCXXABI_SUPPORTS_${flagname}_FLAG ${flag})
+  endforeach()
+endmacro()
+
+# For each specified flag, add that flag to 'LIBCXXABI_COMPILE_FLAGS' if the
+# flag is supported by the C compiler.
+macro(add_c_compile_flags_if_supported)
+  foreach(flag ${ARGN})
+      mangle_name("${flag}" flagname)
+      check_c_compiler_flag("${flag}" "LIBCXXABI_SUPPORTS_${flagname}_FLAG")
+      add_compile_flags_if(LIBCXXABI_SUPPORTS_${flagname}_FLAG ${flag})
+  endforeach()
+endmacro()
+
+# Add a list of flags to 'LIBCXXABI_LINK_FLAGS'.
+macro(add_link_flags)
+  foreach(f ${ARGN})
+    list(APPEND LIBCXXABI_LINK_FLAGS ${f})
+  endforeach()
+endmacro()
+
+# If 'condition' is true then add the specified list of flags to
+# 'LIBCXXABI_LINK_FLAGS'
+macro(add_link_flags_if condition)
+  if (${condition})
+    add_link_flags(${ARGN})
+  endif()
+endmacro()
+
+# For each specified flag, add that flag to 'LIBCXXABI_LINK_FLAGS' if the
+# flag is supported by the C++ compiler.
+macro(add_link_flags_if_supported)
+  foreach(flag ${ARGN})
+    mangle_name("${flag}" flagname)
+    check_cxx_compiler_flag("${flag}" "LIBCXXABI_SUPPORTS_${flagname}_FLAG")
+    add_link_flags_if(LIBCXXABI_SUPPORTS_${flagname}_FLAG ${flag})
+  endforeach()
+endmacro()
+
+# Add a list of libraries or link flags to 'LIBCXXABI_LIBRARIES'.
+macro(add_library_flags)
+  foreach(lib ${ARGN})
+    list(APPEND LIBCXXABI_LIBRARIES ${lib})
+  endforeach()
+endmacro()
+
+# if 'condition' is true then add the specified list of libraries and flags
+# to 'LIBCXXABI_LIBRARIES'.
+macro(add_library_flags_if condition)
+  if(${condition})
+    add_library_flags(${ARGN})
+  endif()
+endmacro()
+
+# Turn a comma separated CMake list into a space separated string.
+macro(split_list listname)
+  string(REPLACE ";" " " ${listname} "${${listname}}")
+endmacro()

cmake/Modules/HandleOutOfTreeLLVM.cmake

+macro(find_llvm_parts)
+# Rely on llvm-config.
+  set(CONFIG_OUTPUT)
+  if(NOT LLVM_CONFIG_PATH)
+    find_program(LLVM_CONFIG_PATH "llvm-config")
+  endif()
+  if(DEFINED LLVM_PATH)
+    set(LLVM_INCLUDE_DIR ${LLVM_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
+    set(LLVM_PATH ${LLVM_PATH} CACHE PATH "Path to LLVM source tree")
+    set(LLVM_MAIN_SRC_DIR ${LLVM_PATH})
+    set(LLVM_CMAKE_PATH "${LLVM_PATH}/cmake/modules")
+  elseif(LLVM_CONFIG_PATH)
+    message(STATUS "Found LLVM_CONFIG_PATH as ${LLVM_CONFIG_PATH}")
+    set(LIBCXXABI_USING_INSTALLED_LLVM 1)
+    set(CONFIG_COMMAND ${LLVM_CONFIG_PATH}
+      "--includedir"
+      "--prefix"
+      "--src-root")
+    execute_process(
+      COMMAND ${CONFIG_COMMAND}
+      RESULT_VARIABLE HAD_ERROR
+      OUTPUT_VARIABLE CONFIG_OUTPUT
+    )
+    if(NOT HAD_ERROR)
+      string(REGEX REPLACE
+        "[ \t]*[\r\n]+[ \t]*" ";"
+        CONFIG_OUTPUT ${CONFIG_OUTPUT})
+    else()
+      string(REPLACE ";" " " CONFIG_COMMAND_STR "${CONFIG_COMMAND}")
+      message(STATUS "${CONFIG_COMMAND_STR}")
+      message(FATAL_ERROR "llvm-config failed with status ${HAD_ERROR}")
+    endif()
+
+    list(GET CONFIG_OUTPUT 0 INCLUDE_DIR)
+    list(GET CONFIG_OUTPUT 1 LLVM_OBJ_ROOT)
+    list(GET CONFIG_OUTPUT 2 MAIN_SRC_DIR)
+
+    set(LLVM_INCLUDE_DIR ${INCLUDE_DIR} CACHE PATH "Path to llvm/include")
+    set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
+    set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
+
+    # --cmakedir is supported since llvm r291218 (4.0 release)
+    execute_process(
+      COMMAND ${LLVM_CONFIG_PATH} --cmakedir
+      RESULT_VARIABLE HAD_ERROR
+      OUTPUT_VARIABLE CONFIG_OUTPUT
+      ERROR_QUIET)
+    if(NOT HAD_ERROR)
+      string(STRIP "${CONFIG_OUTPUT}" LLVM_CMAKE_PATH)
+    else()
+      set(LLVM_CMAKE_PATH
+          "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
+    endif()
+  else()
+    set(LLVM_FOUND OFF)
+    message(WARNING "UNSUPPORTED LIBCXXABI CONFIGURATION DETECTED: "
+                    "llvm-config not found and LLVM_PATH not defined.\n"
+                    "Reconfigure with -DLLVM_CONFIG_PATH=path/to/llvm-config "
+                    "or -DLLVM_PATH=path/to/llvm-source-root.")
+    return()
+  endif()
+
+  if (EXISTS "${LLVM_CMAKE_PATH}")
+    list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_PATH}")
+  elseif (EXISTS "${LLVM_MAIN_SRC_DIR}/cmake/modules")
+    list(APPEND CMAKE_MODULE_PATH "${LLVM_MAIN_SRC_DIR}/cmake/modules")
+  else()
+    set(LLVM_FOUND OFF)
+    message(WARNING "Neither ${LLVM_CMAKE_PATH} nor ${LLVM_MAIN_SRC_DIR}/cmake/modules found")
+    return()
+  endif()
+
+  set(LLVM_FOUND ON)
+endmacro(find_llvm_parts)
+
+macro(configure_out_of_tree_llvm)
+  message(STATUS "Configuring for standalone build.")
+  set(LIBCXXABI_STANDALONE_BUILD 1)
+
+  find_llvm_parts()
+
+  # Add LLVM Functions --------------------------------------------------------
+  if (LLVM_FOUND AND LIBCXXABI_USING_INSTALLED_LLVM)
+    include(LLVMConfig) # For TARGET_TRIPLE
+  else()
+    if (WIN32)
+      set(LLVM_ON_UNIX 0)
+      set(LLVM_ON_WIN32 1)
+    else()
+      set(LLVM_ON_UNIX 1)
+      set(LLVM_ON_WIN32 0)
+    endif()
+  endif()
+  if (LLVM_FOUND)
+    include(AddLLVM OPTIONAL)
+  endif()
+
+  # LLVM Options --------------------------------------------------------------
+  if (NOT DEFINED LLVM_INCLUDE_TESTS)
+    set(LLVM_INCLUDE_TESTS ${LLVM_FOUND})
+  endif()
+  if (NOT DEFINED LLVM_INCLUDE_DOCS)
+    set(LLVM_INCLUDE_DOCS ${LLVM_FOUND})
+  endif()
+  if (NOT DEFINED LLVM_ENABLE_SPHINX)
+    set(LLVM_ENABLE_SPHINX OFF)
+  endif()
+
+  # Required LIT Configuration ------------------------------------------------
+  # Define the default arguments to use with 'lit', and an option for the user
+  # to override.
+  set(LIT_ARGS_DEFAULT "-sv --show-xfail --show-unsupported")
+  if (MSVC OR XCODE)
+    set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
+  endif()
+  set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
+
+  # Required doc configuration
+  if (LLVM_ENABLE_SPHINX)
+    find_package(Sphinx REQUIRED)
+  endif()
+
+  if (LLVM_ON_UNIX AND NOT APPLE)
+    set(LLVM_HAVE_LINK_VERSION_SCRIPT 1)
+  else()
+    set(LLVM_HAVE_LINK_VERSION_SCRIPT 0)
+  endif()
+endmacro(configure_out_of_tree_llvm)
+
+configure_out_of_tree_llvm()

cmake/Modules/MacroEnsureOutOfSourceBuild.cmake

+# MACRO_ENSURE_OUT_OF_SOURCE_BUILD(<errorMessage>)
+
+macro( MACRO_ENSURE_OUT_OF_SOURCE_BUILD _errorMessage )
+
+string( COMPARE EQUAL "${CMAKE_SOURCE_DIR}" "${CMAKE_BINARY_DIR}" _insource )
+if( _insource )
+ message( SEND_ERROR "${_errorMessage}" )
+ message( FATAL_ERROR
+ "In-source builds are not allowed.
+ CMake would overwrite the makefiles distributed with libcxxabi.
+ Please create a directory and run cmake from there, passing the path
+ to this source directory as the last argument.
+ This process created the file `CMakeCache.txt' and the directory `CMakeFiles'.
+ Please delete them."
+ )
+endif( _insource )
+
+endmacro( MACRO_ENSURE_OUT_OF_SOURCE_BUILD )

src/CMakeLists.txt

   add_definitions(-DHAVE___CXA_THREAD_ATEXIT_IMPL)
 endif()
 
-# Generate library list
-set(libraries ${LIBCXXABI_CXX_ABI_LIBRARIES})
-
 if (LIBCXXABI_ENABLE_THREADS)
-  append_if(libraries LIBCXXABI_HAS_PTHREAD_LIB pthread)
+  add_library_flags_if(LIBCXXABI_HAS_PTHREAD_LIB pthread)
 endif()
 
-append_if(libraries LIBCXXABI_HAS_C_LIB c)
+add_library_flags_if(LIBCXXABI_HAS_C_LIB c)
 if (LIBCXXABI_USE_LLVM_UNWINDER)
   # Prefer using the in-tree version of libunwind, either shared or static. If
   # none are found fall back to using -lunwind.
   # FIXME: Is it correct to prefer the static version of libunwind?
   if (NOT LIBCXXABI_ENABLE_STATIC_UNWINDER AND (TARGET unwind_shared OR HAVE_LIBUNWIND))
-    list(APPEND libraries unwind_shared)
+    list(APPEND LIBCXXABI_LIBRARIES unwind_shared)
   elseif (LIBCXXABI_ENABLE_STATIC_UNWINDER AND (TARGET unwind_static OR HAVE_LIBUNWIND))
-    list(APPEND libraries unwind_static)
+    list(APPEND LIBCXXABI_LIBRARIES unwind_static)
   else()
-    list(APPEND libraries unwind)
+    list(APPEND LIBCXXABI_LIBRARIES unwind)
   endif()
 else()
-  append_if(libraries LIBCXXABI_HAS_GCC_S_LIB gcc_s)
+  add_library_flags_if(LIBCXXABI_HAS_GCC_S_LIB gcc_s)
 endif()
 if (MINGW)
   # MINGW_LIBRARIES is defined in config-ix.cmake
-  list(APPEND libraries ${MINGW_LIBRARIES})
+  list(APPEND LIBCXXABI_LIBRARIES ${MINGW_LIBRARIES})
 endif()
 
 # Setup flags.
-append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_HAS_FPIC_FLAG -fPIC)
-append_if(LIBCXXABI_LINK_FLAGS LIBCXXABI_HAS_NODEFAULTLIBS_FLAG -nodefaultlibs)
+add_compile_flags_if_supported(-fPIC)
+add_link_flags_if_supported(-nodefaultlibs)
 
 set(LIBCXXABI_SHARED_LINK_FLAGS)
 

   endif()
 endif()
 
-string(REPLACE ";" " " LIBCXXABI_COMPILE_FLAGS "${LIBCXXABI_COMPILE_FLAGS}")
-string(REPLACE ";" " " LIBCXXABI_LINK_FLAGS "${LIBCXXABI_LINK_FLAGS}")
-string(REPLACE ";" " " LIBCXXABI_SHARED_LINK_FLAGS "${LIBCXXABI_SHARED_LINK_FLAGS}")
+split_list(LIBCXXABI_COMPILE_FLAGS)
+split_list(LIBCXXABI_LINK_FLAGS)
+split_list(LIBCXXABI_SHARED_LINK_FLAGS)
 
 # FIXME: libc++abi.so will not link when modules are enabled because it depends
 # on symbols defined in libc++.so which has not yet been built.

 # Build the shared library.
 if (LIBCXXABI_ENABLE_SHARED)
   add_library(cxxabi_shared SHARED $<TARGET_OBJECTS:cxxabi_objects>)
-  target_link_libraries(cxxabi_shared ${libraries})
+  target_link_libraries(cxxabi_shared ${LIBCXXABI_LIBRARIES})
   set_target_properties(cxxabi_shared
     PROPERTIES
       LINK_FLAGS    "${LIBCXXABI_LINK_FLAGS} ${LIBCXXABI_SHARED_LINK_FLAGS}"

 # Build the static library.
 if (LIBCXXABI_ENABLE_STATIC)
   add_library(cxxabi_static STATIC $<TARGET_OBJECTS:cxxabi_objects>)
-  target_link_libraries(cxxabi_static ${libraries})
+  target_link_libraries(cxxabi_static ${LIBCXXABI_LIBRARIES})
   set_target_properties(cxxabi_static
     PROPERTIES
       LINK_FLAGS    "${LIBCXXABI_LINK_FLAGS}"