Re-fix macOS host + linux-bionic-arm64 target cross-compile

Context: a2fd74c Context: https://github.com/dotnet/runtime/blob/132725d3702d51d78b5f68b0501c5e5845921d04/src/coreclr/nativeaot/docs/android-bionic.md#known-issues Commit a2fd74c had a fatal flaw: it would immediately crash on launch: F DEBUG : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** F DEBUG : Build fingerprint: 'google/raven/raven:14/AP1A.240305.019.A1/11445699:user/release-keys' F DEBUG : Revision: 'MP1.0' F DEBUG : ABI: 'arm64' F DEBUG : Timestamp: 2024-05-01 11:01:48.710687354-0400 F DEBUG : Process uptime: 1s F DEBUG : Cmdline: com.jonathanpeppers.nativeaot F DEBUG : pid: 10516, tid: 10516, name: ppers.nativeaot >>> com.jonathanpeppers.nativeaot <<< F DEBUG : uid: 10371 F DEBUG : tagged_addr_ctrl: 0000000000000001 (PR_TAGGED_ADDR_ENABLE) F DEBUG : signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0000000000000006 F DEBUG : Cause: null pointer dereference F DEBUG : x0 0000000000000006 x1 0000007fda6f3340 x2 0000007eb6852980 x3 0000007fda6ef330 F DEBUG : x4 0000007eb6852a00 x5 0000000000000004 x6 0000000001414d4c x7 0000007eb6852004 F DEBUG : x8 0000007eb6852980 x9 0000000000000006 x10 000000000000000f x11 757274736e6f6320 F DEBUG : x12 676e696c6c61632c x13 000180000045dfd0 x14 0000000000018510 x15 0000000000000000 F DEBUG : x16 0000007eb7b3d680 x17 0000007eb7a5fb00 x18 0000007eb6d90000 x19 0000007fda6f3340 F DEBUG : x20 0000007eb6852980 x21 0000000000000006 x22 0000007eb7b4b000 x23 0000007eb67c9e70 F DEBUG : x24 0000007fda6f0518 x25 0000000000000022 x26 0000007eb6843c00 x27 0000007fda6f0500 F DEBUG : x28 0000007eb7b49000 x29 0000007fda6ef2e0 F DEBUG : lr 0000007b57aebc80 sp 0000007fda6ef2c0 pc 0000007b57aebcb0 pst 0000000080001000 F DEBUG : 1 total frames F DEBUG : backtrace: F DEBUG : #00 pc 00000000000c1cb0 /data/app/~~y5LQdnO4d1iwNk2Z6I4Jpg==/com.jonathanpeppers.nativeaot-HJbM4Jw2CNRiWe4-Rn2IxA==/lib/arm64/libdotnet.so (BuildId: 21c56035e6fc411dab6ab373715ba35e82c0fb5f) Turns out™ that the [android-bionic.md][0] documentation has a [Known issues][1] section, which has a *better* workaround: > If you hit > `error : version script assignment of 'V1.0' to symbol '_init' failed: symbol not defined` - > this is a known issue with .NET 8 release dotnet/runtime#92272, you > can add following lines to your csproj to work around: > > ```xml > <ItemGroup Condition="$(RuntimeIdentifier.StartsWith('linux-bionic'))"> > <LinkerArg Include="-Wl,--undefined-version" /> > </ItemGroup> > ``` That workaround *does* work, better than the attempted workaround in a2fd74c. Update `libdotnet.targets` to use the documented workaround. Additionally, `libdotnet.so` depends on `libc++_shared.so`: % $ANDROID_NDK_HOME/toolchains/llvm/prebuilt/darwin-x86_64/bin/llvm-readelf -a DotNet/bin/Release/net8.0/linux-bionic-arm64/publish/libdotnet.so 0x0000000000000001 (NEEDED) Shared library: [libdl.so] 0x0000000000000001 (NEEDED) Shared library: [libc++_shared.so] 0x0000000000000001 (NEEDED) Shared library: [libc.so] and `libc++_shared.so` needs to be included in the `.apk`. Add a new `_CopyLibcppShared` target which copies `libc++_shared.so` from the NDK into `Native/app/src/main/jniLibs/arm64-v8a`. Failure to do so results in an error at startup: E AndroidRuntime: java.lang.UnsatisfiedLinkError: Unable to load native library "/data/app/~~p6cCHwNVFV8uzhECCUKmCg==/com.jonathanpeppers.nativeaot-wVDfzgY8K6AbDgBPnccb_w==/lib/arm64/libnativeaot.so": dlopen failed: library "libc++_shared.so" not found: needed by /data/app/~~p6cCHwNVFV8uzhECCUKmCg==/com.jonathanpeppers.nativeaot-wVDfzgY8K6AbDgBPnccb_w==/lib/arm64/libdotnet.so in namespace clns-4 Update `README.md` to contain clear(er) instruction on how to build and run this sample. [0]: https://github.com/dotnet/runtime/blob/132725d3702d51d78b5f68b0501c5e5845921d04/src/coreclr/nativeaot/docs/android-bionic.md [1]: https://github.com/dotnet/runtime/blob/132725d3702d51d78b5f68b0501c5e5845921d04/src/coreclr/nativeaot/docs/android-bionic.md#known-issues
jonathanpeppers · May 1, 2024 · 81a9388 · 81a9388
1 parent a2fd74c
commit 81a9388
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diff --git a/DotNet/libdotnet.targets b/DotNet/libdotnet.targets
@@ -9,16 +9,12 @@
   </PropertyGroup>
 
   <PropertyGroup Condition="$(RuntimeIdentifier.StartsWith('linux-bionic'))">
-    <LinkStandardCPlusPlusLibrary>true</LinkStandardCPlusPlusLibrary>
     <CppCompilerAndLinker>$(_NdkBinDir)/$(_NdkClangPrefix)clang++</CppCompilerAndLinker>
     <ObjCopyName>$(_NdkBinDir)/llvm-objcopy</ObjCopyName>
   </PropertyGroup>
 
   <ItemGroup Condition="$(RuntimeIdentifier.StartsWith('linux-bionic'))">
-    <LinkerArg Include="-Wl,--defsym,_init=__libc_init" />
-    <LinkerArg Include="-Wl,--defsym,_fini=__libc_fini" />
-    <LinkerArg Include="-L &quot;$(_NdkSysrootDir)&quot;" />
-    <NativeSystemLibrary Include="c" />
+    <LinkerArg Include="-Wl,--undefined-version" />
   </ItemGroup>
 
   <Target Name="_ValidateEnvironment"
@@ -32,4 +28,17 @@
         Text="NDK 'sysroot' dir `$(_NdkSysrootDir)` does not exist. You're on your own."
     />
   </Target>
+
+  <Target Name="_CopyLibcppShared"
+      AfterTargets="Publish">
+    <PropertyGroup>
+      <_JniLibsDir>../Native/app/src/main/jniLibs/arm64-v8a</_JniLibsDir>
+    </PropertyGroup>
+    <MakeDir Directories="../Native/app/src/main/jniLibs/arm64-v8a" />
+    <ItemGroup>
+      <_Source Include="$(_NdkSysrootDir)\libc++_shared.so" />
+      <_Target Include="$(_JniLibsDir)\libc++_shared.so" />
+    </ItemGroup>
+    <Copy SourceFiles="@(_Source)" DestinationFiles="@(_Target)" />
+  </Target>
 </Project>
diff --git a/README.md b/README.md
@@ -2,6 +2,33 @@
 
 A .NET 8, NativeAOT example on Android.
 
+## Getting started
+
+Configure your environment: the following environment variables are required:
+
+  * `ANDROID_NDK_HOME`: The path to an Android NDK installation.
+  * `ANDROID_HOME`: The path to an Android SDK installation.
+
+Build the project:
+
+```console
+dotnet build
+dotnet publish DotNet/libdotnet.csproj
+(cd Native && ./gradlew assembleRelease)
+```
+
+Install the app:
+
+```console
+$ANDROID_HOME/platform-tools/adb install Native/app/build/outputs/apk/release/app-release.apk
+```
+
+Run the app:
+
+```console
+$ANDROID_HOME/platform-tools/adb shell am start com.jonathanpeppers.nativeaot/android.app.NativeActivity
+```
+
 ## Example using SkiaSharp
 
 This sample has a C++ Android Studio project: