Use __config_site when building libc++. Also cleanup ABI versioning doc

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@250261 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -321,6 +321,9 @@ if (LIBCXX_NEEDS_SITE_CONFIG)
     include/__config_site.in
     ${LIBCXX_BINARY_DIR}/__config_site
     @ONLY)
+  # Provide the config definitions by included the generated __config_site
+  # file at compile time.
+  add_compile_flags("-include ${LIBCXX_BINARY_DIR}/__config_site")
 endif()
 
 #===============================================================================

cmake/Modules/HandleLibcxxFlags.cmake

@@ -49,10 +49,12 @@ macro(define_if_not condition 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(${def} ON)
-    add_definitions(-D${def})
     set(LIBCXX_NEEDS_SITE_CONFIG ON)
   endif()
 endmacro()
@@ -60,14 +62,12 @@ endmacro()
 macro(config_define_if_not condition def)
   if (NOT ${condition})
     set(${def} ON)
-    add_definitions(-D${def})
     set(LIBCXX_NEEDS_SITE_CONFIG ON)
   endif()
 endmacro()
 
 macro(config_define value def)
   set(${def} ${value})
-  add_definitions(-D${def}=${value})
   set(LIBCXX_NEEDS_SITE_CONFIG ON)
 endmacro()
 

docs/index.rst

@@ -128,6 +128,7 @@ Design Documents
    :maxdepth: 1
 
    DesignDocs/CapturingConfigInfo
+   DesignDocs/ABIVersioning
 
 
 * `<atomic> design <http://libcxx.llvm.org/atomic_design.html>`_

test/libcxx/test/config.py

@@ -444,7 +444,9 @@ class Configuration(object):
     def configure_compile_flags_abi_version(self):
         abi_version = self.get_lit_conf('abi_version', '').strip()
         abi_unstable = self.get_lit_bool('abi_unstable')
-        if abi_version:
+        # Only add the ABI version when it is non-default.
+        # FIXME(EricWF): Get the ABI version from the "__config_site".
+        if abi_version and abi_version != '1':
           self.cxx.compile_flags += ['-D_LIBCPP_ABI_VERSION=' + abi_version]
         if abi_unstable:
           self.config.available_features.add('libcpp-abi-unstable')