Hi, I was also trying to cross-compile v8 7.6 for android ARM on ubuntu machine: *gn gen out.gn/android.arm64.release -vv --args="is_debug=false is_component_build=false v8_use_snapshot=true v8_static_library=true v8_use_external_startup_data=false v8_enable_i18n_support=true v8_monolithic=true use_custom_libcxx=false target_cpu=\"arm64\""* Running *nm --demangle* on the v8's static library(v8_monolith.a) which is created by building v8 has symbols as *std::__cxx11 * which should be *std::__ndk. * Any idea what else can i try ? I even tried with v8 8.3 but didnot get any help. What would be the proper gn arguments to link against libc++ from the NDK ?
On Wednesday, June 17, 2020 at 11:45:24 AM UTC+5:30 jc_m...@emailplus.org wrote: > I was able to get it running by defining `use_custom_libcxx=false`. > > In hindsight it's rather straightforward. It doesn't work on 7.3, but it > works fine on 8.3. > I have read in a couple of places that `use_custom_libcxx=false` is not > supported on Android. It looks like this information is outdated if using a > recent version of v8. > > On Tue, Jun 16, 2020, at 2:52 PM, Jean-Claude Monnin wrote: > > I'm facing the same issue. I built v8 for Android, and when linking > `libv8_monolith.a` in my app using NDK, there are link errors. The app and > the other third-party libs use the NDK libc++ expecting the `std::__ndk1` > namespace, but v8 is expecting `std::__1`. > > I couldn't find a way to tell the v8 build system to use the libc++ from > the NDK. Is there really no way to use the default libc++ from NDK when > compiling v8? > > In case the only solution is to use the libc++ version imposed by v8 > everywhere (like Darin Dimitrov did), how is it done? > I'm couldn't find an appropriate lib to link in > `buildtools/third_party/libc++`. I could find some `libc++_static.a` in the > v8 source tree, but they are in `third_party/android_ndk/` and they > use `std::__ndk1` (see [1] and [2]). > > Any advice of how to correctly use v8 with NDK is appreciated. > The official documentation helps to get v8 compiled standalone ( > https://v8.dev/docs/cross-compile-arm), but the difficult part starts > when trying linking it with other libs and code. > > I tried with both 7.3-lkgr and 8.3-lkgr v8 versions. > > > -------------------------- > [1]: Searching for `libc++_static.a` in the v8 source tree > > find . -name libc++_static.a > > ./third_party/android_ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/i686-linux-android/libc++_static.a > > ./third_party/android_ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/aarch64-linux-android/libc++_static.a > > ./third_party/android_ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/x86_64-linux-android/libc++_static.a > > ./third_party/android_ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/arm-linux-androideabi/libc++_static.a > > ./third_party/android_ndk/sources/cxx-stl/llvm-libc++/libs/armeabi-v7a/libc++_static.a > > ./third_party/android_ndk/sources/cxx-stl/llvm-libc++/libs/arm64-v8a/libc++_static.a > > ./third_party/android_ndk/sources/cxx-stl/llvm-libc++/libs/x86_64/libc++_static.a > > ./third_party/android_ndk/sources/cxx-stl/llvm-libc++/libs/x86/libc++_static.a > > [2]: checking the demangled names used in the static library > > ~/Android/Sdk/ndk/21.3.6528147/toolchains/aarch64-linux-android-4.9/prebuilt/linux-x86_64/bin/aarch64-linux-android-nm > > --demangle > third_party/android_ndk/toolchains/llvm/prebuilt/linux-x86_64/sysroot/usr/lib/i686-linux-android/libc++_static.a > > | grep string > 00000000 W > std::__ndk1::__basic_string_common<true>::__throw_length_error() const > .... > > On Wed, Feb 20, 2019, at 10:41 PM, Darin Dimitrov wrote: > > Turns out that V8 is building against a custom STL passing > the _LIBCPP_ABI_UNSTABLE flag. So in order to build my final executable I > had to use this same STL instead of the default libc++_static.a library > provided by the NDK. > > On Wednesday, February 13, 2019 at 9:24:34 AM UTC+2, Darin Dimitrov wrote: > > Tom, thanks for the reply. The DefaultPlatform method was just an example. > Looking at the public API in v8.h > <https://github.com/v8/v8/blob/master/include/v8.h> there are quite a lot > of references to C++ objects from the standard library and I am getting > tons of those similar linker errors. That's what made me think that I must > be doing something wrong. > > I managed to successfully compile and link if I manually modify > _LIBCPP_ABI_NAMESPACE in the "third_party/libc++/trunk/include/__config" > include file. But I feel that it should somehow be possible to specify the > libc++ location when building v8 so that it uses the one from the NDK. > > On Tuesday, February 12, 2019 at 10:15:04 PM UTC+2, Tom Anderson wrote: > > Usually C++ objects should not be passed over library boundaries. In this > case though, the issue could be fixed by adding a wrapper for > v8::platform::DefaultPlatform::DefaultPlatform() that takes a C-style > pointer instead of a unique_ptr. > > I'm also not sure if v8_libplatform is meant to be redistributed in this > way, though the V8 team can say for sure. > > On Tuesday, February 12, 2019 at 8:05:19 AM UTC-8, Darin Dimitrov wrote: > > Further narrowing this down. > > In V8 *7.2*, libc++ is taken from the NDK: > > -isystem../../third_party/android_ndk/sources/cxx-stl/llvm-libc++/include > -isystem../../third_party/android_ndk/sources/cxx-stl/llvm-libc++abi/ > include > > whereas in V8 *7.3*, a different libc++ is used: > > -isystem../../buildtools/third_party/libc++/trunk/include > -isystem../../buildtools/third_party/libc++abi/trunk/include > > And the difference between the two versions is that the one from the NDK > defines the following std namespace override: > > #ifndef _LIBCPP_ABI_NAMESPACE > # define _LIBCPP_ABI_NAMESPACE _LIBCPP_CONCAT(__ndk,_LIBCPP_ABI_VERSION) > #endif > > while the custom one uses this: > > #ifndef _LIBCPP_ABI_NAMESPACE > # define _LIBCPP_ABI_NAMESPACE _LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION) > #endif > > So the question is, what would be the proper gn arguments to link against > libc++ from the NDK? > > I have tried setting use_custom_libcxx=false but in this case no -isystem > is specified and the build fails as it cannot find some common includes > such as <memory> and <functional>. > > On Monday, February 11, 2019 at 6:09:49 PM UTC+2, Darin Dimitrov wrote: > > I was able to bisect the issue to the following commit in which the V8 > DEPS were updated: > https://chromium.googlesource.com/v8/v8/+/843535b893968a89f98b295cd7b1b265ca2927c1 > > > -- > -- > v8-users mailing list > v8-u...@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+u...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > > > > -- > -- > v8-users mailing list > v8-u...@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+u...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/v8-users/8288f622-6c11-450e-987b-9399f3cb6953%40www.fastmail.com > > <https://groups.google.com/d/msgid/v8-users/8288f622-6c11-450e-987b-9399f3cb6953%40www.fastmail.com?utm_medium=email&utm_source=footer> > . > > > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. 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