在android嵌入式中构建v8时出错

Question

我试图在我的Android NDK项目中导入v8 7.6.90作为静态库，但它在链接过程中失败了。

这是我对v8 build的args.gn配置：

android_unstripped_runtime_outputs = true
v8_use_external_startup_data = false
is_debug = false
symbol_level = 1
target_cpu = "arm"
target_os = "android"
use_goma = false
v8_enable_i18n_support = false
v8_static_library = true
is_component_build = false
v8_monolithic = true
v8_android_log_stdout = true

编译后它确实编译并给了我一个libv8_monolith.a ，然后我开始设置我的Android项目。

的CMakeLists.txt：

cmake_minimum_required(VERSION 3.4.1)
add_library(v8 STATIC IMPORTED)
set_target_properties( v8 PROPERTIES IMPORTED_LOCATION ${CMAKE_SOURCE_DIR}/libs/${ANDROID_ABI}/libv8_monolith.a)
add_library( # Sets the name of the library.
        native-lib

        # Sets the library as a shared library.
        SHARED

        # Provides a relative path to your source file(s).
        ${CMAKE_SOURCE_DIR}/src/main/cpp/native-lib.cpp)

target_include_directories( native-lib PRIVATE ${CMAKE_SOURCE_DIR}/libs/include)

find_library( # Sets the name of the path variable.
        log-lib

        # Specifies the name of the NDK library that
        # you want CMake to locate.
        log)

target_link_libraries( # Specifies the target library.
        native-lib
        v8
        # Links the target library to the log library
        # included in the NDK.
        ${log-lib})

的build.gradle：

externalNativeBuild {
    cmake {
        cppFlags "-std=c++0x"
    }
}
ndk {
    abiFilters "armeabi-v7a"
}

native-lib.cpp在https://chromium.googlesource.com/v8/v8/+/master/samples/hello-world.cc中运行相同的示例

但是ld总是抱怨错误：

../../src/compiler/graph-visualizer.cc:0: error: undefined reference to 'vtable for std::__1::basic_ios<char, std::__1::char_traits<char> >'
/Users/fredguo/Library/Android/sdk/ndk-bundle/toolchains/llvm/prebuilt/darwin-x86_64/lib/gcc/arm-linux-androideabi/4.9.x/../../../../arm-linux-androideabi/bin/ld: the vtable symbol may be undefined because the class is missing its key function
error: undefined reference to 'v8::platform::NewDefaultPlatform(int, v8::platform::IdleTaskSupport, v8::platform::InProcessStackDumping, std::__ndk1::unique_ptr<v8::TracingController, std::__ndk1::default_delete<v8::TracingController> >)'

我试图objdump我的libv8_monolith.a ：

objdump -D app/libs/armeabi-v7a/libv8_monolith.a | grep NewDefault

Disassembly of section .text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
_ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
       4:       81 b0 01 2b     blhs    #442884 <_ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE+0x6C210>
Disassembly of section .rel.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
.rel.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
Disassembly of section .ARM.exidx.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
.ARM.exidx.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
Disassembly of section .rel.ARM.exidx.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
.rel.ARM.exidx.text._ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE:
Disassembly of section .text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
_ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
Disassembly of section .rel.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
.rel.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
Disassembly of section .ARM.exidx.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
.ARM.exidx.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
Disassembly of section .rel.ARM.exidx.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:
.rel.ARM.exidx.text._ZN2v811ArrayBuffer9Allocator19NewDefaultAllocatorEv:

_ZN2v88platform18NewDefaultPlatformEiNS0_15IdleTaskSupportENS0_21InProcessStackDumpingENSt3__110unique_ptrINS_17TracingControllerENS3_14default_deleteIS5_EEEE

应该

v8::platform::NewDefaultPlatform(int, v8::platform::IdleTaskSupport, v8::platform::InProcessStackDumping, std::__1::unique_ptr<v8::TracingController, std::__1::default_delete<v8::TracingController> >)

但是，在错误消息中，ld尝试查找std::__ndk1::unique_ptr<v8::TracingController, std::__ndk1::default_delete<v8::TracingController> >)

我认为他们有不同的命名空间，但我该如何解决这个问题呢？ 我在https://groups.google.com/forum/#!topic/v8-users/Jb1VSouy2Z0找到了类似的问题，但该解决方案对我不起作用。

Answer 1

尝试在v8/buildtools/third_party/libc++/trunk/include/__config修改名称空间宏：

从_LIBCPP_CONCAT(__,_LIBCPP_ABI_VERSION)到_LIBCPP_CONCAT(__ndk,_LIBCPP_ABI_VERSION) 。

希望这可以帮助。