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JNA: Support GraalVM (R6) #13

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JNA: Support GraalVM (R6) #13

wants to merge 5 commits into from

Commits on Jun 13, 2024

  1. Add support for GraalVM 

    Adds a JAR publication at `jna-graalvm.jar`, with accompanying
build infrastructure, which provides support for JNA within the
context of the Substrate Virtual Machine (SVM).

GraalVM Native Image targets use SVM instead of JVM at runtime.
JNA's current strategy of unpacking libraries at runtime works
under SVM, but is suboptimal; the binary is native, so it can
simply include JNA object code for the current platform directly.

To accomplish this, several GraalVM "feature" implementations are
provided in this new publication. By default, regular JNA access
is enabled through the `JavaNativeAccess` feature; this class
enables reflection and runtime JNI configurations for downstream
projects which use JNA.

Another feature, `SubstrateStaticJNA`, is experimental because it
relies on unstable GraalVM APIs, but instead of loading JNA at
runtime from a dynamic library, it builds JNA into the final
native image with a static object.

These features are enabled through a resource within `META-INF`,
called `native-image.properties`, which is picked up by the native
image compiler at build time. The new artifact only needs to be
present for GraalVM native targets at build time; otherwise, the
classes and libraries in `jna-graalvm.jar` are inert.

Includes tested support for:
- macOS aarch64
- Linux amd64

- feat: add `jna-graalvm.jar` publication
- feat: add base `JavaNativeAccess` feature for auto-config of JNA
- feat: add initial implementation of `SubstrateStaticJNA` feature
- test: sample/test gradle build for native image
- chore: ci config to run native sample
- chore: add readme to `lib/gvm`

Signed-off-by: Sam Gammon <[email protected]>
Signed-off-by: Dario Valdespino <[email protected]>
Co-authored-by: Sam Gammon <[email protected]>
Co-authored-by: Dario Valdespino <[email protected]>
    @sgammon @darvld
    sgammon and darvld committed Jun 13, 2024
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  2. Static-compatible init of JNA native layer 

    When operating under static linkage in SVM (Native Image), JNA's
`JNI_OnLoad` hooks are not run. We need to sanity-check at the
first JNI border and run static initialization manually.

Additionally, `JNI_OnLoad` should be provided in static contexts
as `JNI_OnLoad_jnidispatch`. This changeset fixes both issues.

Signed-off-by: Sam Gammon <[email protected]>
Signed-off-by: Dario Valdespino <[email protected]>
    @sgammon @darvld
    sgammon authored and darvld committed Jun 13, 2024
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  3. Avoid polymorphic dispatch over JNI 

    When linked statically on GraalVM, JNI symbols declared in the
overloaded form cannot be resolved. Luckily, all of `Native`'s
callsites are in `Pointer` or itself, and all `native` methods
of `Native` are non-public.

This PR adjusts the JNA C API to avoid using overloaded `read`,
`write`, or `getDirectByteBuffer`. Callsites are amended in
`Pointer` accordingly.

Signed-off-by: Sam Gammon <[email protected]>
Signed-off-by: Dario Valdespino <[email protected]>
    @sgammon @darvld
    sgammon authored and darvld committed Jun 13, 2024
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  4. Support JNA over Static JNI on GraalVM 

    Implements a new optional linkage feature, called Static JNI, under
GraalVM Native Image.

With `com.sun.jna.SubstrateStaticJNA` enabled (opt-in), JNA is
loaded eagerly at image build time, and then linked against a static
copy of `libjnidispatch` at image link-time.

The result is that `libjnidispatch.a` is embedded within the final
image. No precursor library unpacking step is necessary before using
JNA in this circumstance, because JNA's native layer is built
directly into the image itself.

- feat: implement static jni feature
- chore: full gvm ci build
- chore: add static jni sample

Signed-off-by: Sam Gammon <[email protected]>
Signed-off-by: Dario Valdespino <[email protected]>
Co-authored-by: Sam Gammon <[email protected]>
Co-authored-by: Dario Valdespino <[email protected]>
    @sgammon @darvld
    sgammon and darvld committed Jun 13, 2024
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  5. Update dist and lib/native 

    Signed-off-by: Sam Gammon <[email protected]>
Signed-off-by: Dario Valdespino <[email protected]>
    @sgammon @darvld
    sgammon authored and darvld committed Jun 13, 2024
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