Android 9 (P)版本解决VNDK library: XXX’s ABI has EXTENDING CHANGES

Android 9 (P)开发适配指南系列博客目录：

Adnroid 9 (P) recovery升级Map of '@/cache/recovery/block.map’failed问题分析指南
Android 9 (P)版本解决VNDK library: XXX’s ABI has EXTENDING CHANGES
Android 9 (P)非SDK API限制调用开发指南
Android 9 (P)适配以太网功能开发指南
Android 9 (P)在user模式下无法使用fastboot烧录怎么破
Android 9 (P)静默安装/卸载App适配终极指南

引言

此时的我吃着火锅唱着歌，进行着Android P(此P非彼P，Android 9)的适配工作。我真的只能说每次Android版本的迭代更新，都是对我们的一次炼狱般的摧残啊，各种适配啊，我真的想说fuck the coding。但是吐槽归吐槽，为了我热爱的coding事业，让我们愉快的适配起来。这不问题又来了，当我们修改liblog源码时提示error: VNDK library: liblog’s ABI has EXTENDING CHANGES，木得办法兵来将挡水来土掩，只能上了。

注意：本文演示的代码是Android P高通msm8953平台。

一.问题现象

当我们尝试对Android源码下面的system/core/liblog源码目录下面的文件添加一些接口时，适配问题出现了，编译一直报错，如下所示：

QSSI: not enabled for msm8953_64 target as vendor/qcom/proprietary/release/QSSI/QSSI_enforced_targets_list.txt was not found.
ninja: no work to do.
ninja: no work to do.
No need to regenerate ninja file
No need to regenerate ninja file
[ 50% 1/2] glob .
[ 16% 1/6] //system/core/liblog:liblog header-abi-diff liblog.so.abidiff
FAILED: out/soong/.intermediates/system/core/liblog/liblog/android_arm64_armv8-a_core_shared/liblog.so.abidiff
(prebuilts/clang-tools/linux-x86/bin/header-abi-diff -allow-unreferenced-changes -allow-unreferenced-elf-symbol-changes -lib liblog -arch arm64 -o out/soong/.intermediates/system/core/liblog/liblog/android_arm64_armv8-a_core_shared/liblog.so.abidiff -new out/soong/.intermediates/system/core/liblog/liblog/android_arm64_armv8-a_core_shared/liblog.so.lsdump -old out/soong/.intermediates/system/core/liblog/liblog/android_arm64_armv8-a_core_shared/liblog.so_ref.lsdump)|| (echo ' ---- Please update abi references by running platform/development/vndk/tools/header-checker/utils/create_reference_dumps.py -l liblog ----' && exit 1)
******************************************************
error: VNDK library: liblog's ABI has EXTENDING CHANGES Please check compatiblity report at : out/soong/.intermediates/system/core/liblog/liblog/android_arm64_armv8-a_core_shared/liblog.so.abidiff
******************************************************---- Please update abi references by running platform/development/vndk/tools/header-checker/utils/create_reference_dumps.py -l liblog ----
ninja: build stopped: subcommand failed.
09:34:59 ninja failed with: exit status 1

不用怀疑，这个不是你源码的问题。这个是由于Android P增加了VNDK的限制。

二.VNDK是什么

VNDK(Vendor Native Development Kit)是一组专门用于vendor实现其HAL的lib库，因为自Android 8.0以来，Google引入了Treble架构，希望对vendor和system分区进行解耦处理，期待实现：framwork进程不加载vendor共享库，vendor进程仅加载vendor共享库（和部分framework共享库），而framework进程和vendor进程之间通过HIDL和hwbinder来通信。总结为如下几点：

platform和Vendor的构建是相互隔离的；
platform lib对应 system.img；
vendor lib对应 vendor.img；
大多数情况下，Vendor lib跟系统核心不能相互使用；Vendor lib不允许dlopen私有的系统库；
合作伙伴不允许为自己的产品在VNDK新增lib，只能贡献到AOSP；

关于VNDK的具体介绍可以参见如下博客：
ABI 稳定性
Android : 供应商原生开发套件 (VNDK)
供应商原生开发套件 (VNDK)

三.怎么解决

在代码中搜索，发现 development/vndk/tools/header-checker/header-abi-diff/src 中的 header_abi_diff.cpp 报出的错误。错误提示如下：

184   if (should_emit_warning_message) {185     llvm::errs() << "******************************************************\n"
186                  << error_or_warning_str
187                  << "VNDK library: "
188                  << lib_name
189                  << "'s ABI has "
190                  << status_str
191                  << unreferenced_change_str
192                  << " Please check compatiblity report at : "
193                  << compatibility_report << "\n"
194                  << "******************************************************\n";
195   }

于是，直接修改代码，让里面的 main 直接返回 abi_util::CompatibilityStatusIR::Compatible; 然后重新编译这个文件，覆盖到代码中的检查库。全编译。通过！！

下面让我们详细讲解一下步骤：

修改development/vndk/tools/header-checker/header-abi-diff/src/header_abi_diff.cpp，改动如下：

--- a/development/vndk/tools/header-checker/header-abi-diff/src/header_abi_diff.cpp
+++ b/development/vndk/tools/header-checker/header-abi-diff/src/header_abi_diff.cpp
@@ -182,21 +182,21 @@ int main(int argc, const char **argv) {bool should_emit_warning_message = ShouldEmitWarningMessage(status);if (should_emit_warning_message) {-    llvm::errs() << "******************************************************\n"
-                 << error_or_warning_str
-                 << "VNDK library: "
-                 << lib_name
-                 << "'s ABI has "
-                 << status_str
-                 << unreferenced_change_str
-                 << " Please check compatiblity report at : "
-                 << compatibility_report << "\n"
-                 << "******************************************************\n";
+//    llvm::errs() << "******************************************************\n"
+//                 << error_or_warning_str
+//                 << "VNDK library: "
+//                 << lib_name
+//                 << "'s ABI has "
+//                 << status_str
+//                 << unreferenced_change_str
+//                 << " Please check compatiblity report at : "
+//                 << compatibility_report << "\n"
+//                 << "******************************************************\n";}-  if (!advice_only && should_emit_warning_message) {-    return status;
-  }

重新编译 development/vndk/tools/header-checker，编译命令如下:

mmm  development/vndk/tools/header-checker/ -j32
616+0 records in
616+0 records out
630784 bytes (631 kB, 616 KiB) copied, 0.0032836 s, 192 MB/s
[ 66% 2/3] glob .
[100% 5/5] Install: out/host/linux-x86/bin/header-abi-diff

复制 out/host/linux-x86/bin/header-abi-diff 到 prebuilts/clang-tools/linux-x86/bin 中覆盖，命令如下：

cp out/host/linux-x86/bin/header-abi-diff prebuilts/clang-tools/linux-x86/bin/header-abi-diff

重新souurce lunhcer，再执行你需要修改的so文件，譬如我们这里的是liblog，我们编译一把:

make  -j32 liblog//编译结果
vendor/qcom/build/tasks/generate_extra_images.mk:558: warning: overriding commands for target `kernelclean'
device/qcom/common/generate_extra_images.mk:558: warning: ignoring old commands for target `kernelclean'
[100% 76/76] build out/host/linux-x86/obj32/SHARED_LIBRARIES/liblog_intermediates/liblog.so.toc

好了,大功告成可以愉快的修改VNDK的相关改动了。

结语

各位乡亲们，Android P版本解决VNDK library: XXX’s ABI has EXTENDING CHANGES就结束了，整的我腰酸背痛啊。Android版本升级之时就是我等受苦之时啊。

写在最后

好了如上就是Android P版本解决VNDK library: XXX’s ABI has EXTENDING CHANGES的所有，如有问题或者有任何疑问请及时沟通或者交流，也可点个赞或者吐槽一番也是可以的。so goodbye。