[monodroid] Use right calling convention on Windows #2525
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Context: xamarin/java.interop#403 Make sure we use `__stdcall` when crosscompiling for mxe/win. This allows us to crosscompile for Windows without installing Java SDK for Windows. The include path is put BEFORE other includes, so that the `jni_md.h` is found before the one in Mac SDK in darwin SDK subdirectory (like /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/include/darwin)
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To clarify, a problem would be e.g. JI_API jint
java_interop_jnienv_get_version (JNIEnv *env)
{
jint _r_ = (*env)->GetVersion (env);
return _r_;
}Because Correct? Are there any other issues/concerns? |
Yes. Pretty much every JNI call was broken.
I don't know about any other. There's also |
jonpryor
pushed a commit
that referenced
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Dec 18, 2018
Context: xamarin/java.interop#403 On Windows, JNI defines `JNICALL` as `__stdcall`: most Java APIs need to use the `__stdcall` calling convention. In particular this includes the function pointers within the `JNIEnv` struct: `JNIEnv::GetVersion()` is a `__stdcall` function pointer, as well as most other function pointers: // <jni.h> /* partial */ struct JNINativeInterface_ { jint (JNICALL *GetVersion)(JNIEnv *env); }; `JNICALL` is `__stdcall` on Windows, and undefined (cdecl) elsewhere. Unfortunately, we build `src/monodroid` for Windows *from macOS* with MXE, and we didn't have a full or complete JDK Windows installation. The result is that we have a *calling convention mismatch* between e.g. `libmono-android.debug.dll` and `jvm.dll`, which can result in runtime call stack corruption. Fix this by adding a new `jni/win32/jni_md.h` file and inserting `jni/win32` into CMake's `include_directories` *before* the OS-native JDK include directory, e.g. `/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/include/darwin`, ensuring that `JNICALL` is set to `__stdcall` when compiling *for* Windows *from* macOS. This allows us to cross-compile for Windows without installing the Java SDK for Windows.
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Context: xamarin/java.interop#403
Make sure we use
__stdcallwhen crosscompiling for mxe/win.This allows us to crosscompile for Windows without installing Java SDK
for Windows.
The include path is put BEFORE other includes, so that the
jni_md.his found before the one in Mac JDK, in
darwinSDK subdirectory (like/Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home/include/darwin).