Make it possible to link against libstdc++ as well as libsupc++ with CMake.

Linking against libstdc++, rather than libsupc++, is probably better
for people who need to link against clients of libstdc++.  Because
libsupc++ is provided only as a static library, its globals are not
shared between the static library and the copy linked into libstdc++.
This has been found to cause at least one test failure.

This also removes a number of symbols which were multiply defined
between libstdc++ and libc++, only when linking with libstdc++.

Differential Revision: http://llvm-reviews.chandlerc.com/D1825

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@192075 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -44,7 +44,7 @@ option(LIBCXX_ENABLE_CXX0X "Enable -std=c++0x and use of c++0x language features
 option(LIBCXX_ENABLE_SHARED "Build libc++ as a shared library." ON)
 option(LIBCXX_INSTALL_SUPPORT_HEADERS "Install libc++ support headers." ON)
 
-set(CXXABIS none libcxxabi libcxxrt libsupc++)
+set(CXXABIS none libcxxabi libcxxrt libstdc++ libsupc++)
 if (NOT DEFINED LIBCXX_CXX_ABI)
   set(LIBCXX_CXX_ABI "none")
 endif()
@@ -133,13 +133,22 @@ macro(setup_abi_lib abipathvar abidefines abilibs abifiles abidirs)
     )
 endmacro()
 
-if ("${LIBCXX_CXX_ABI}" STREQUAL "libsupc++")
+if ("${LIBCXX_CXX_ABI}" STREQUAL "libstdc++" OR
+    "${LIBCXX_CXX_ABI}" STREQUAL "libsupc++")
   set(_LIBSUPCXX_INCLUDE_FILES
     cxxabi.h bits/c++config.h bits/os_defines.h bits/cpu_defines.h
     bits/cxxabi_tweaks.h bits/cxxabi_forced.h
     )
-  setup_abi_lib("LIBCXX_LIBSUPCXX_INCLUDE_PATHS" "-D__GLIBCXX__"
+  if ("${LIBCXX_CXX_ABI}" STREQUAL "libstdc++")
-    "supc++" "${_LIBSUPCXX_INCLUDE_FILES}" "bits"
+    set(_LIBSUPCXX_DEFINES "-DLIBSTDCXX")
+    set(_LIBSUPCXX_LIBNAME stdc++)
+  else()
+    set(_LIBSUPCXX_DEFINES "")
+    set(_LIBSUPCXX_LIBNAME supc++)
+  endif()
+  setup_abi_lib("LIBCXX_LIBSUPCXX_INCLUDE_PATHS"
+    "-D__GLIBCXX__ ${_LIBSUPCXX_DEFINES}"
+    "${_LIBSUPCXX_LIBNAME}" "${_LIBSUPCXX_INCLUDE_FILES}" "bits"
     )
 elseif ("${LIBCXX_CXX_ABI}" STREQUAL "libcxxabi")
   setup_abi_lib("LIBCXX_LIBCXXABI_INCLUDE_PATHS" ""
@@ -151,7 +160,7 @@ elseif ("${LIBCXX_CXX_ABI}" STREQUAL "libcxxrt")
     )
 elseif (NOT "${LIBCXX_CXX_ABI}" STREQUAL "none")
   message(FATAL_ERROR
-    "Currently libsupc++, libcxxabi, libcxxrt and none are "
+    "Currently libstdc++, libsupc++, libcxxabi, libcxxrt and none are "
     "supported for c++ abi."
     )
 endif ()

src/new.cpp

@@ -224,6 +224,8 @@ bad_array_new_length::what() const _NOEXCEPT
 
 #endif // _LIBCPPABI_VERSION
 
+#ifndef LIBSTDCXX
+
 void
 __throw_bad_alloc()
 {
@@ -232,4 +234,6 @@ __throw_bad_alloc()
 #endif
 }
 
+#endif // !LIBSTDCXX
+
 }  // std

src/stdexcept.cpp

@@ -127,7 +127,7 @@ logic_error::operator=(const logic_error& le) _NOEXCEPT
     return *this;
 }
 
-#ifndef _LIBCPPABI_VERSION
+#if !defined(_LIBCPPABI_VERSION) && !defined(LIBSTDCXX)
 
 logic_error::~logic_error() _NOEXCEPT
 {
@@ -171,7 +171,7 @@ runtime_error::operator=(const runtime_error& le) _NOEXCEPT
     return *this;
 }
 
-#ifndef _LIBCPPABI_VERSION
+#if !defined(_LIBCPPABI_VERSION) && !defined(LIBSTDCXX)
 
 runtime_error::~runtime_error() _NOEXCEPT
 {

test/lit.cfg

@@ -234,13 +234,26 @@ link_flags_str = lit_config.params.get('link_flags', None)
 if link_flags_str is None:
     link_flags_str = getattr(config, 'link_flags', None)
     if link_flags_str is None:
+      cxx_abi = getattr(config, 'cxx_abi', None)
+      if cxx_abi == 'libstdc++':
+        link_flags += ['-lstdc++']
+      elif cxx_abi == 'libsupc++':
+        link_flags += ['-lsupc++']
+      elif cxx_abi == 'libcxxabi':
+        link_flags += ['-lc++abi']
+      elif cxx_abi == 'none':
+        pass
+      else:
+        lit_config.fatal('C++ ABI setting %s unsupported for tests' % cxx_abi)
+
       if sys.platform == 'darwin':
         link_flags += ['-lSystem']
       elif sys.platform == 'linux2':
-            link_flags += ['-lsupc++', '-lgcc_eh', '-lc', '-lm', '-lpthread',
+        link_flags += [ '-lgcc_eh', '-lc', '-lm', '-lpthread',
               '-lrt', '-lgcc_s']
       else:
         lit_config.fatal("unrecognized system")
+
       lit_config.note("inferred link_flags as: %r" % (link_flags,))
 if not link_flags_str is None:
     link_flags += shlex.split(link_flags_str)

test/lit.site.cfg.in

@@ -5,6 +5,7 @@ config.libcxx_src_root       = "@LIBCXX_SOURCE_DIR@"
 config.libcxx_obj_root       = "@LIBCXX_BINARY_DIR@"
 config.python_executable     = "@PYTHON_EXECUTABLE@"
 config.enable_shared         = @LIBCXX_ENABLE_SHARED@
+config.cxx_abi               = "@LIBCXX_CXX_ABI@"
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@LIBCXX_SOURCE_DIR@/test/lit.cfg")

www/index.html

@@ -248,11 +248,18 @@ End of search list.
      We can now run CMake:
      <ul>
        <li><code>CC=clang CXX=clang++ cmake -G "Unix Makefiles"
-                -DLIBCXX_CXX_ABI=libsupc++
+                -DLIBCXX_CXX_ABI=libstdc++
                 -DLIBCXX_LIBSUPCXX_INCLUDE_PATHS="/usr/include/c++/4.7/;/usr/include/c++/4.7/x86_64-linux-gnu/"
                 -DCMAKE_BUILD_TYPE=Release
                 -DCMAKE_INSTALL_PREFIX=/usr
                 &lt;libc++-source-dir&gt;</code></li>
+       <li>You can also substitute <code>-DLIBCXX_CXX_ABI=libsupc++</code>
+       above, which will cause the library to be linked to libsupc++ instead
+       of libstdc++, but this is only recommended if you know that you will
+       never need to link against libstdc++ in the same executable as libc++.
+       GCC ships libsupc++ separately but only as a static library.  If a
+       program also needs to link against libstdc++, it will provide its
+       own copy of libsupc++ and this can lead to subtle problems.
        <li><code>make</code></li>
        <li><code>sudo make install</code></li>
      </ul>