[runtimes] Move common functions from Handle{Libcxx,Libcxxabi,Libunwind}Flags.cmake to runtimes/cmake/Modules/HandleFlags.cmake

Reviewed By: phosek, #libunwind, #libc, #libc_abi

Spies: arichardson, libcxx-commits

Differential Revision: https://reviews.llvm.org/D144395

7 files changed, 119 insertions, 334 deletions

diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 3a958e7..3e7a4ac 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -12,6 +12,7 @@ set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
+  "${CMAKE_CURRENT_SOURCE_DIR}/../runtimes/cmake/Modules"
   "${LLVM_COMMON_CMAKE_UTILS}"
   "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
diff --git a/libcxx/cmake/Modules/HandleLibcxxFlags.cmake b/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
index 7251254..d8aee2a 100644
--- a/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
+++ b/libcxx/cmake/Modules/HandleLibcxxFlags.cmake
@@ -5,102 +5,10 @@
 # - LIBCXX_LIBRARIES: libraries to link libc++ to.
 
 include(CheckCXXCompilerFlag)
+include(HandleFlags)
 
 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 ":" "_COLON_" 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}" "CXX_SUPPORTS_${flagname}_FLAG")
-endmacro()
-
-macro(append_flags DEST)
-  foreach(value ${ARGN})
-    list(APPEND ${DEST} ${value})
-    list(APPEND ${DEST} ${value})
-  endforeach()
-endmacro()
-
-# If the specified 'condition' is true then append the specified list of flags to DEST
-macro(append_flags_if condition DEST)
-  if (${condition})
-    list(APPEND ${DEST} ${ARGN})
-  endif()
-endmacro()
-
-# Add each flag in the list specified by DEST if that flag is supported by the current compiler.
-macro(append_flags_if_supported DEST)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    append_flags_if(CXX_SUPPORTS_${flagname}_FLAG ${DEST} ${flag})
-  endforeach()
-endmacro()
-
-# Add a macro definition if condition is true.
-macro(define_if condition def)
-  if (${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)
-  endif()
-endmacro()
-
-macro(config_define_if_not condition def)
-  if (NOT ${condition})
-    set(${def} ON)
-  endif()
-endmacro()
-
-macro(config_define value def)
-  set(${def} ${value})
-endmacro()
-
 # Add a list of flags to all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS',
 # 'LIBCXX_COMPILE_FLAGS' and 'LIBCXX_LINK_FLAGS'.
 macro(add_target_flags)
@@ -224,11 +132,6 @@ macro(add_library_flags_if condition)
   endif()
 endmacro()
 
-# Turn a comma separated CMake list into a space separated string.
-macro(split_list listname)
-  string(REPLACE ";" " " ${listname} "${${listname}}")
-endmacro()
-
 # For each specified flag, add that link flag to the provided target.
 # The flags are added with the given visibility, i.e. PUBLIC|PRIVATE|INTERFACE.
 function(target_add_link_flags_if_supported target visibility)
@@ -240,15 +143,3 @@ function(target_add_link_flags_if_supported target visibility)
     endif()
   endforeach()
 endfunction()
-
-# For each specified flag, add that compile flag to the provided target.
-# The flags are added with the given visibility, i.e. PUBLIC|PRIVATE|INTERFACE.
-function(target_add_compile_flags_if_supported target visibility)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    if (CXX_SUPPORTS_${flagname}_FLAG)
-      target_compile_options(${target} ${visibility} ${flag})
-    endif()
-  endforeach()
-endfunction()
diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 8f48d40..a92ada7 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -12,6 +12,7 @@ set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
+  "${CMAKE_CURRENT_SOURCE_DIR}/../runtimes/cmake/Modules"
   "${LLVM_COMMON_CMAKE_UTILS}"
   "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
diff --git a/libcxxabi/cmake/Modules/HandleLibcxxabiFlags.cmake b/libcxxabi/cmake/Modules/HandleLibcxxabiFlags.cmake
index 25d4789..976c6b5 100644
--- a/libcxxabi/cmake/Modules/HandleLibcxxabiFlags.cmake
+++ b/libcxxabi/cmake/Modules/HandleLibcxxabiFlags.cmake
@@ -5,104 +5,10 @@
 # - LIBCXXABI_LIBRARIES: libraries to link libc++abi to.
 
 include(CheckCXXCompilerFlag)
+include(HandleFlags)
 
 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}" "CXX_SUPPORTS_${flagname}_FLAG")
-endmacro()
-
-macro(append_flags DEST)
-  foreach(value ${ARGN})
-    list(APPEND ${DEST} ${value})
-    list(APPEND ${DEST} ${value})
-  endforeach()
-endmacro()
-
-# If the specified 'condition' is true then append the specified list of flags to DEST
-macro(append_flags_if condition DEST)
-  if (${condition})
-    list(APPEND ${DEST} ${ARGN})
-  endif()
-endmacro()
-
-# Add each flag in the list specified by DEST if that flag is supported by the current compiler.
-macro(append_flags_if_supported DEST)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    append_flags_if(CXX_SUPPORTS_${flagname}_FLAG ${DEST} ${flag})
-  endforeach()
-endmacro()
-
-# Add a macro definition if condition is true.
-macro(define_if condition def)
-  if (${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} ${value})
-  set(LIBCXXABI_NEEDS_SITE_CONFIG ON)
-endmacro()
-
 # Add a list of flags to all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS',
 # 'LIBCXXABI_COMPILE_FLAGS' and 'LIBCXXABI_LINK_FLAGS'.
 macro(add_target_flags)
@@ -235,20 +141,3 @@ macro(add_library_flags_if condition)
     add_library_flags(${ARGN})
   endif()
 endmacro()
-
-# Turn a comma separated CMake list into a space separated string.
-macro(split_list listname)
-  string(REPLACE ";" " " ${listname} "${${listname}}")
-endmacro()
-
-# For each specified flag, add that compile flag to the provided target.
-# The flags are added with the given visibility, i.e. PUBLIC|PRIVATE|INTERFACE.
-function(target_add_compile_flags_if_supported target visibility)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    if (CXX_SUPPORTS_${flagname}_FLAG)
-      target_compile_options(${target} ${visibility} ${flag})
-    endif()
-  endforeach()
-endfunction()
diff --git a/libunwind/CMakeLists.txt b/libunwind/CMakeLists.txt
index 5c54788..f82fa0a 100644
--- a/libunwind/CMakeLists.txt
+++ b/libunwind/CMakeLists.txt
@@ -10,6 +10,7 @@ set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
+  "${CMAKE_CURRENT_SOURCE_DIR}/../runtimes/cmake/Modules"
   "${LLVM_COMMON_CMAKE_UTILS}"
   "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
diff --git a/libunwind/cmake/Modules/HandleLibunwindFlags.cmake b/libunwind/cmake/Modules/HandleLibunwindFlags.cmake
index c5d7603..47b7083 100644
--- a/libunwind/cmake/Modules/HandleLibunwindFlags.cmake
+++ b/libunwind/cmake/Modules/HandleLibunwindFlags.cmake
@@ -6,104 +6,10 @@
 
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
+include(HandleFlags)
 
 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}" "CXX_SUPPORTS_${flagname}_FLAG")
-endmacro()
-
-macro(append_flags DEST)
-  foreach(value ${ARGN})
-    list(APPEND ${DEST} ${value})
-    list(APPEND ${DEST} ${value})
-  endforeach()
-endmacro()
-
-# If the specified 'condition' is true then append the specified list of flags to DEST
-macro(append_flags_if condition DEST)
-  if (${condition})
-    list(APPEND ${DEST} ${ARGN})
-  endif()
-endmacro()
-
-# Add each flag in the list specified by DEST if that flag is supported by the current compiler.
-macro(append_flags_if_supported DEST)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    append_flags_if(CXX_SUPPORTS_${flagname}_FLAG ${DEST} ${flag})
-  endforeach()
-endmacro()
-
-# Add a macro definition if condition is true.
-macro(define_if condition def)
-  if (${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(LIBUNWIND_NEEDS_SITE_CONFIG ON)
-  endif()
-endmacro()
-
-macro(config_define_if_not condition def)
-  if (NOT ${condition})
-    set(${def} ON)
-    set(LIBUNWIND_NEEDS_SITE_CONFIG ON)
-  endif()
-endmacro()
-
-macro(config_define value def)
-  set(${def} ${value})
-  set(LIBUNWIND_NEEDS_SITE_CONFIG ON)
-endmacro()
-
 # Add a list of flags to all of 'CMAKE_CXX_FLAGS', 'CMAKE_C_FLAGS',
 # 'LIBUNWIND_COMPILE_FLAGS' and 'LIBUNWIND_LINK_FLAGS'.
 macro(add_target_flags)
@@ -276,20 +182,3 @@ macro(add_library_flags_if condition)
     add_library_flags(${ARGN})
   endif()
 endmacro()
-
-# Turn a comma separated CMake list into a space separated string.
-macro(split_list listname)
-  string(REPLACE ";" " " ${listname} "${${listname}}")
-endmacro()
-
-# For each specified flag, add that compile flag to the provided target.
-# The flags are added with the given visibility, i.e. PUBLIC|PRIVATE|INTERFACE.
-function(target_add_compile_flags_if_supported target visibility)
-  foreach(flag ${ARGN})
-    mangle_name("${flag}" flagname)
-    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
-    if (CXX_SUPPORTS_${flagname}_FLAG)
-      target_compile_options(${target} ${visibility} ${flag})
-    endif()
-  endforeach()
-endfunction()
diff --git a/runtimes/cmake/Modules/HandleFlags.cmake b/runtimes/cmake/Modules/HandleFlags.cmake
new file mode 100644
index 0000000..4a62b67
--- /dev/null
+++ b/runtimes/cmake/Modules/HandleFlags.cmake
@@ -0,0 +1,113 @@
+
+include(CheckCXXCompilerFlag)
+
+unset(add_flag_if_supported)
+
+# Mangle the name of a compiler flag into a valid CMake identifier.
+# Ex: --std=c++11 -> STD_EQ_CXX11
+macro(mangle_name str output)
+  string(STRIP "${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}" "CXX_SUPPORTS_${flagname}_FLAG")
+endmacro()
+
+macro(append_flags DEST)
+  foreach(value ${ARGN})
+    list(APPEND ${DEST} ${value})
+    list(APPEND ${DEST} ${value})
+  endforeach()
+endmacro()
+
+# If the specified 'condition' is true then append the specified list of flags to DEST
+macro(append_flags_if condition DEST)
+  if (${condition})
+    list(APPEND ${DEST} ${ARGN})
+  endif()
+endmacro()
+
+# Add each flag in the list specified by DEST if that flag is supported by the current compiler.
+macro(append_flags_if_supported DEST)
+  foreach(flag ${ARGN})
+    mangle_name("${flag}" flagname)
+    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
+    append_flags_if(CXX_SUPPORTS_${flagname}_FLAG ${DEST} ${flag})
+  endforeach()
+endmacro()
+
+# Add a macro definition if condition is true.
+macro(define_if condition def)
+  if (${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)
+  endif()
+endmacro()
+
+macro(config_define_if_not condition def)
+  if (NOT ${condition})
+    set(${def} ON)
+  endif()
+endmacro()
+
+macro(config_define value def)
+  set(${def} ${value})
+endmacro()
+
+# Turn a comma separated CMake list into a space separated string.
+macro(split_list listname)
+  string(REPLACE ";" " " ${listname} "${${listname}}")
+endmacro()
+
+# For each specified flag, add that compile flag to the provided target.
+# The flags are added with the given visibility, i.e. PUBLIC|PRIVATE|INTERFACE.
+function(target_add_compile_flags_if_supported target visibility)
+  foreach(flag ${ARGN})
+    mangle_name("${flag}" flagname)
+    check_cxx_compiler_flag("${flag}" "CXX_SUPPORTS_${flagname}_FLAG")
+    if (CXX_SUPPORTS_${flagname}_FLAG)
+      target_compile_options(${target} ${visibility} ${flag})
+    endif()
+  endforeach()
+endfunction()