Move c++ configs from buildtools to build/config/c++ [buildtools-side change]

third_party/libc++/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/toolchain/toolchain.gni")
 
 # Sanitizer builds need to override operator new, operator delete, and
 # some exception handling symbols, so libc++ must be a shared library
 # to prevent duplicate symbol errors when linking.
@@ skipping 22 matching lines @@
       # similar to that overrides the default elf merging rules, and
       # make tcmalloc's gn config pass that to all its dependencies,
       # then remove this override here.
       "_LIBCPP_OVERRIDABLE_FUNC_VIS=__attribute__((__visibility__(\"default\")))",
     ]
   }
   cflags = [
     "-fPIC",
     "-fstrict-aliasing",
   ]
-  cflags_cc = [
-    "-nostdinc++",
-    "-isystem" + rebase_path("trunk/include", root_build_dir),
-    "-isystem" + rebase_path("../libc++abi/trunk/include", root_build_dir),
-    "-std=c++11",
-  ]
-  if (is_linux && current_cpu == "arm") {
-    cflags_c = [ "-isystem" +
-                 rebase_path("../libunwind/trunk/include", root_build_dir) ]
-    cflags_cc += [ "-isystem" +
-                   rebase_path("../libunwind/trunk/include", root_build_dir) ]
-  }
-}
-
-config("no_libstdcpp") {
-  # Make sure we don't link against libc++ or libstdc++.
-  ldflags = [ "-nodefaultlibs" ]
-
-  # Unfortunately, there's no way to disable linking against just
-  # libc++ (besides using clang instead of clang++); -nodefaultlibs
-  # removes all of the default libraries, so add back the ones that we
-  # need.
-  libs = [
-    "c",
-    "m",
-  ]
-
-  if (!is_mac) {
-    libs += [
-      "gcc_s",
-      "rt",
-    ]
-  }
-
-  if (is_mac && using_sanitizer) {
-    lib_dirs = [ "//third_party/llvm-build/Release+Asserts/lib/clang/$clang_version/lib/darwin" ]
-
-    if (is_asan) {
-      libs += [ "clang_rt.asan_osx_dynamic" ]
-    }
-  }
 }
 
 if (libcpp_is_static) {
   link_target_type = "source_set"
 } else {
   link_target_type = "shared_library"
 }
 target(link_target_type, "libc++") {
+  visibility = [ "//build/config:exe_and_shlib_deps" ]

[Nico, 2017/06/30 20:07:04]

Hmm, this adds a cycling dependency between files in src.git and buildtools.git.
This tends to cause headaches down the road. If we want to do this, maybe we
should move the libc++ build files into sec/build/secondary?

...but I think they are here because v8 wants them too. This CL here would be
inconvenient for v8 too?

[Tom Anderson, 2017/06/30 21:08:28]

Wouldn't that just require rolling buildtools at the same time as build?  I'm
not opposed to just removing the visibility addition if you think it will cause
problems.

[Michael Achenbach, 2017/07/03 06:37:57]

Our deps roller usually auto-rolls build and buildtools at the same time into
v8. So if thing's keep running with this build<>buildtools dependency, I'm not
opposed.

   sources = [
     "trunk/src/algorithm.cpp",
     "trunk/src/any.cpp",
     "trunk/src/bind.cpp",
     "trunk/src/chrono.cpp",
     "trunk/src/condition_variable.cpp",
     "trunk/src/debug.cpp",
     "trunk/src/exception.cpp",
     "trunk/src/functional.cpp",
     "trunk/src/future.cpp",
@@ skipping 18 matching lines @@
     "trunk/src/valarray.cpp",
     "trunk/src/variant.cpp",
   ]
   configs -= [
     "//build/config/compiler:chromium_code",
     "//build/config/compiler:no_rtti",
     "//build/config/gcc:no_exceptions",
   ]
   configs += [
     ":config",
-    ":no_libstdcpp",
     "//build/config/compiler:no_chromium_code",
     "//build/config/compiler:rtti",
     "//build/config/sanitizers:sanitizer_options_link_helper",
   ]
   defines = [ "_LIBCPP_BUILDING_LIBRARY" ]
 
   deps = [
     "//buildtools/third_party/libc++abi",
   ]
 }
-
-group("libcxx_proxy") {
-  deps = [
-    ":libc++",
-  ]
-  public_configs = [ ":no_libstdcpp" ]
-}