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 It looks like this information is outdated if using a recent version of v8.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-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. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to v8-users+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. > > > -- > -- > 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. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+unsubscr...@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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