[libc++] Use functions instead of global variables to set libc++ build flags

This commit follows the trend of doing things per-target instead of
modifying the C++ flags globally. It does so for visibility-related
flags, other basic build flags and Windows-specific flags.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@373517 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -522,50 +522,60 @@ remove_flags("/D_DEBUG" "/MTd" "/MDd" "/MT" "/Md")
 remove_flags(-Wno-pedantic -pedantic-errors -pedantic)
 
 # Required flags ==============================================================
-if (LIBCXX_HAS_MUSL_LIBC OR LIBCXX_TARGETING_CLANG_CL)
-  # musl's pthread implementations uses volatile types in their structs which is
-  # not a constexpr in C++11 but is in C++14, so we use C++14 with musl.
-  set(LIBCXX_STANDARD_VER c++14 CACHE STRING "internal option to change build dialect")
-else()
-  set(LIBCXX_STANDARD_VER c++11 CACHE STRING "internal option to change build dialect")
-endif()
-add_compile_flags_if_supported(-std=${LIBCXX_STANDARD_VER})
-add_compile_flags_if_supported("/std:${LIBCXX_STANDARD_VER}")
-mangle_name("LIBCXX_SUPPORTS_STD_EQ_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME)
-mangle_name("LIBCXX_SUPPORTS_STD_COLON_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME_MSVC)
-if(NOT ${SUPPORTS_DIALECT_NAME} AND NOT ${SUPPORTS_DIALECT_NAME_MSVC})
-  if(NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" AND NOT "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC")
-    message(FATAL_ERROR "C++11 or greater is required but the compiler does not support ${LIBCXX_STANDARD_VER}")
+function(cxx_add_basic_build_flags target)
+  if (LIBCXX_HAS_MUSL_LIBC OR LIBCXX_TARGETING_CLANG_CL)
+    # musl's pthread implementations uses volatile types in their structs which is
+    # not a constexpr in C++11 but is in C++14, so we use C++14 with musl.
+    set(LIBCXX_STANDARD_VER c++14 CACHE STRING "internal option to change build dialect")
+  else()
+    set(LIBCXX_STANDARD_VER c++11 CACHE STRING "internal option to change build dialect")
+  endif()
+  target_add_compile_flags_if_supported(${target} PRIVATE -std=${LIBCXX_STANDARD_VER})
+  target_add_compile_flags_if_supported(${target} PRIVATE "/std:${LIBCXX_STANDARD_VER}")
+  mangle_name("LIBCXX_SUPPORTS_STD_EQ_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME)
+  mangle_name("LIBCXX_SUPPORTS_STD_COLON_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME_MSVC)
+  if(NOT ${SUPPORTS_DIALECT_NAME} AND NOT ${SUPPORTS_DIALECT_NAME_MSVC})
+    if(NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" AND NOT "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC")
+      message(FATAL_ERROR "C++11 or greater is required but the compiler does not support ${LIBCXX_STANDARD_VER}")
+    endif()
   endif()
-endif()
-
-# On all systems the system c++ standard library headers need to be excluded.
-# MSVC only has -X, which disables all default includes; including the crt.
-# Thus, we do nothing and hope we don't accidentally include any of the C++
-# headers
-add_compile_flags_if_supported(-nostdinc++)
 
-# Hide all inline function definitions which have not explicitly been marked
-# visible. This prevents new definitions for inline functions from appearing in
-# the dylib when get ODR used by another function.
-add_compile_flags_if_supported(-fvisibility-inlines-hidden)
+  # On all systems the system c++ standard library headers need to be excluded.
+  # MSVC only has -X, which disables all default includes; including the crt.
+  # Thus, we do nothing and hope we don't accidentally include any of the C++
+  # headers
+  target_add_compile_flags_if_supported(${target} PUBLIC -nostdinc++)
+
+  # Hide all inline function definitions which have not explicitly been marked
+  # visible. This prevents new definitions for inline functions from appearing in
+  # the dylib when get ODR used by another function.
+  target_add_compile_flags_if_supported(${target} PRIVATE -fvisibility-inlines-hidden)
+
+  # Our visibility annotations are not quite right for non-Clang compilers,
+  # so we end up not exporting all the symbols we should. In the future, we
+  # can improve the situation by providing an explicit list of exported
+  # symbols on all compilers.
+  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    target_add_compile_flags_if_supported(${target} PRIVATE -fvisibility=hidden)
+  endif()
 
-if (LIBCXX_CONFIGURE_IDE)
-  # This simply allows IDE to process <experimental/coroutine>
-  add_compile_flags_if_supported(-fcoroutines-ts)
-endif()
+  if (LIBCXX_CONFIGURE_IDE)
+    # This simply allows IDE to process <experimental/coroutine>
+    target_add_compile_flags_if_supported(${target} PRIVATE -fcoroutines-ts)
+  endif()
 
-# Let the library headers know they are currently being used to build the
-# library.
-add_definitions(-D_LIBCPP_BUILDING_LIBRARY)
+  # Let the library headers know they are currently being used to build the
+  # library.
+  target_compile_definitions(${target} PRIVATE -D_LIBCPP_BUILDING_LIBRARY)
 
-if (NOT LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS)
-  add_definitions(-D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
-endif()
+  if (NOT LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS)
+    target_compile_definitions(${target} PRIVATE -D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS)
+  endif()
 
-if (LIBCXX_HAS_COMMENT_LIB_PRAGMA)
-  add_definitions(-D_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
-endif()
+  if (LIBCXX_HAS_COMMENT_LIB_PRAGMA)
+    target_compile_definitions(${target} PRIVATE -D_LIBCPP_HAS_COMMENT_LIB_PRAGMA)
+  endif()
+endfunction()
 
 # Warning flags ===============================================================
 function(cxx_add_warning_flags target)
@@ -714,6 +724,31 @@ if (LIBCXX_STANDALONE_BUILD AND SANITIZER_FLAGS)
   add_flags(${SANITIZER_FLAGS})
 endif()
 
+# Windows-related flags =======================================================
+function(cxx_add_windows_flags target)
+  if(WIN32 AND NOT MINGW)
+    target_compile_definitions(${target} PRIVATE
+                                 # Ignore the -MSC_VER mismatch, as we may build
+                                 # with a different compatibility version.
+                                 _ALLOW_MSC_VER_MISMATCH
+                                 # Don't check the msvcprt iterator debug levels
+                                 # as we will define the iterator types; libc++
+                                 # uses a different macro to identify the debug
+                                 # level.
+                                 _ALLOW_ITERATOR_DEBUG_LEVEL_MISMATCH
+                                 # We are building the c++ runtime, don't pull in
+                                 # msvcprt.
+                                 _CRTBLD
+                                 # Don't warn on the use of "deprecated"
+                                 # "insecure" functions which are standards
+                                 # specified.
+                                 _CRT_SECURE_NO_WARNINGS
+                                 # Use the ISO conforming behaviour for conversion
+                                 # in printf, scanf.
+                                 _CRT_STDIO_ISO_WIDE_SPECIFIERS)
+  endif()
+endfunction()
+
 # Configuration file flags =====================================================
 if (NOT LIBCXX_ABI_VERSION EQUAL 1)
   config_define(${LIBCXX_ABI_VERSION} _LIBCPP_ABI_VERSION)

src/CMakeLists.txt

@@ -204,35 +204,6 @@ function(cxx_set_common_defines name)
   if(LIBCXX_CXX_ABI_HEADER_TARGET)
     add_dependencies(${name} ${LIBCXX_CXX_ABI_HEADER_TARGET})
   endif()
-  # Our visibility annotations are not quite right for non-Clang compilers,
-  # so we end up not exporting all the symbols we should. In the future, we
-  # can improve the situation by providing an explicit list of exported
-  # symbols on all compilers.
-  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    target_compile_options(${name} PRIVATE -fvisibility=hidden)
-  endif()
-  if(WIN32 AND NOT MINGW)
-    target_compile_definitions(${name}
-                               PRIVATE
-                                 # Ignore the -MSC_VER mismatch, as we may build
-                                 # with a different compatibility version.
-                                 _ALLOW_MSC_VER_MISMATCH
-                                 # Don't check the msvcprt iterator debug levels
-                                 # as we will define the iterator types; libc++
-                                 # uses a different macro to identify the debug
-                                 # level.
-                                 _ALLOW_ITERATOR_DEBUG_LEVEL_MISMATCH
-                                 # We are building the c++ runtime, don't pull in
-                                 # msvcprt.
-                                 _CRTBLD
-                                 # Don't warn on the use of "deprecated"
-                                 # "insecure" functions which are standards
-                                 # specified.
-                                 _CRT_SECURE_NO_WARNINGS
-                                 # Use the ISO conforming behaviour for conversion
-                                 # in printf, scanf.
-                                 _CRT_STDIO_ISO_WIDE_SPECIFIERS)
-  endif()
 
   if (LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
     target_link_libraries(${name} PUBLIC pstl::ParallelSTL)
@@ -259,8 +230,10 @@ if (LIBCXX_ENABLE_SHARED)
       SOVERSION     "${LIBCXX_ABI_VERSION}"
       DEFINE_SYMBOL ""
   )
+  cxx_add_basic_build_flags(cxx_shared)
   cxx_set_common_defines(cxx_shared)
   cxx_add_warning_flags(cxx_shared)
+  cxx_add_windows_flags(cxx_shared)
 
   # Link against LLVM libunwind
   if (LIBCXXABI_USE_LLVM_UNWINDER)
@@ -360,8 +333,10 @@ if (LIBCXX_ENABLE_STATIC)
       LINK_FLAGS    "${LIBCXX_LINK_FLAGS}"
       OUTPUT_NAME   "c++"
   )
+  cxx_add_basic_build_flags(cxx_static)
   cxx_set_common_defines(cxx_static)
   cxx_add_warning_flags(cxx_static)
+  cxx_add_windows_flags(cxx_static)
 
   if (LIBCXX_HERMETIC_STATIC_LIBRARY)
     # If the hermetic library doesn't define the operator new/delete functions