diff options
Diffstat (limited to 'third_party/libwebrtc/build/config/c++/BUILD.gn')
| -rw-r--r-- | third_party/libwebrtc/build/config/c++/BUILD.gn | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/third_party/libwebrtc/build/config/c++/BUILD.gn b/third_party/libwebrtc/build/config/c++/BUILD.gn new file mode 100644 index 0000000000..e7ed69ec81 --- /dev/null +++ b/third_party/libwebrtc/build/config/c++/BUILD.gn @@ -0,0 +1,145 @@ +import("//build/config/c++/c++.gni") +import("//build/config/chrome_build.gni") +import("//build/config/chromeos/ui_mode.gni") +import("//build/config/dcheck_always_on.gni") +import("//buildtools/deps_revisions.gni") + +assert(use_custom_libcxx, "should only be used if use_custom_libcxx is set") + +declare_args() { + # lldb pretty printing only works when libc++ is built in the __1 (or __ndk1) + # namespaces. For pretty printing to work out-of-the-box on Mac (where lldb + # is primarily used), this flag is set to false to build with the __1 + # namespace (to maintain ABI compatibility, this implies building without + # _LIBCPP_ABI_UNSTABLE). This is not necessary on non-component builds + # because we leave the ABI version set to __1 in that case because libc++ + # symbols are not exported. + # TODO(thomasanderson): Set this to true by default once rL352899 is available + # in MacOS's lldb. + libcxx_abi_unstable = !(is_apple && is_debug && is_component_build) +} + +# TODO(xiaohuic): https://crbug/917533 Crashes on internal ChromeOS build. +# Do unconditionally once the underlying problem is fixed. +if (is_chromeos_ash && is_chrome_branded) { + libcxx_abi_unstable = false +} + +# This is included by reference in the //build/config/compiler:runtime_library +# config that is applied to all targets. It is here to separate out the logic +# that is specific to libc++. Please see that target for advice on what should +# go in :runtime_library vs. :compiler. +config("runtime_library") { + cflags = [] + cflags_cc = [] + defines = [] + include_dirs = [] + ldflags = [] + libs = [] + + if (libcxx_abi_unstable) { + defines += [ "_LIBCPP_ABI_UNSTABLE" ] + } + + if (libcxx_is_shared) { + # When libcxx_is_shared is true, symbols from libc++.so are exported for + # all DSOs to use. If the system libc++ gets loaded (indirectly through + # a system library), then it will conflict with our libc++.so. Add a + # custom ABI version if we're building with _LIBCPP_ABI_UNSTABLE to avoid + # conflicts. + # + # Windows doesn't need to set _LIBCPP_ABI_VERSION since there's no system + # C++ library we could conflict with. + if (libcxx_abi_unstable && !is_win) { + defines += [ "_LIBCPP_ABI_VERSION=Cr" ] + } + } else { + # Don't leak any symbols on a static build. + defines += [ "_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS" ] + if (!export_libcxxabi_from_executables && !is_win) { + defines += [ "_LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS" ] + } + } + + defines += [ "_LIBCPP_ENABLE_NODISCARD" ] + + include_dirs += [ "//buildtools/third_party/libc++" ] + + # Work around a symbol conflict between GRPC and the Fuchsia SDK. + # TODO(crbug.com/1166970): Remove this when resolved. + if (is_fuchsia) { + defines += [ "_LIBCPP_NO_NATIVE_SEMAPHORES" ] + } + + # The Windows component build fails to link with libc++'s debug mode. See + # https://crbug.com/923166#c33, https://crbug.com/923166#c44, and + # https://llvm.org/PR41018. + if (!(is_win && is_component_build)) { + # libc++ has two levels of debug mode. Setting _LIBCPP_DEBUG to zero + # enables most assertions. Setting it to one additionally enables iterator + # debugging. See https://libcxx.llvm.org/docs/DesignDocs/DebugMode.html + if (enable_iterator_debugging) { + defines += [ "_LIBCPP_DEBUG=1" ] + } else if (is_debug || dcheck_always_on) { + defines += [ "_LIBCPP_DEBUG=0" ] + } + } + + if (is_win) { + # Intentionally not using libc++abi on Windows because libc++abi only + # implements the Itanium C++ ABI, and not the Microsoft ABI which we use on + # Windows (and we need to use in order to interoperate correctly with COM + # among other things). + assert(!export_libcxxabi_from_executables, + "Don't use libcxxabi on Windows.") + + cflags_cc += + [ "-I" + rebase_path("$libcxx_prefix/include", root_build_dir) ] + + # Prevent libc++ from embedding linker flags to try to automatically link + # against its runtime library. This is unnecessary with our build system, + # and can also result in build failures if libc++'s name for a library + # does not match ours. + defines += [ "_LIBCPP_NO_AUTO_LINK" ] + + # Add a debug visualizer for Microsoft's debuggers so that they can display + # libc++ types well. + if (libcxx_natvis_include) { + # chrome.natvis listed as an input in //buildtools/third_party/libc++ to + # guarantee relinking on changes. + ldflags += [ "/NATVIS:" + rebase_path("libc++.natvis", root_build_dir) ] + } + } else { + cflags_cc += [ + "-nostdinc++", + "-isystem" + rebase_path("$libcxx_prefix/include", root_build_dir), + "-isystem" + rebase_path("$libcxxabi_prefix/include", root_build_dir), + ] + cflags_objcc = cflags_cc + + defines += [ "CR_LIBCXX_REVISION=$libcxx_revision" ] + + # Make sure we don't link against the system libstdc++ or libc++. + if (is_clang) { + ldflags += [ "-nostdlib++" ] + } else { + # Gcc has a built-in abs() definition with default visibility. + # If it was not disabled, it would conflict with libc++'s abs() + # with hidden visibility. + cflags += [ "-fno-builtin-abs" ] + + ldflags += [ "-nodefaultlibs" ] + + # Unfortunately, there's no way to disable linking against just libc++ + # (gcc doesn't have -notstdlib++: + # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83931); -nodefaultlibs + # removes all of the default libraries, so add back the ones that we need. + libs += [ + "c", + "gcc_s", + "m", + "rt", + ] + } + } +} |