From d48ddea1dcdfc4c21264d1a9e949dafea5a1337b Mon Sep 17 00:00:00 2001
From: You Xie <youxie@meta.com>
Date: Mon, 31 Aug 2026 23:52:27 -0700
Subject: [PATCH] Add a single-.so Vulkan+XNNPACK executorch JNI target

Summary:
Lets the executorch Android JNI sources be compiled from a Buck package other
than their own.

`log.cpp` and the JNI headers were not exported, and `jni_helper.cpp` and
`log.cpp` included their headers by relative path (`#include "log.h"`). That
form only resolves while the file is compiled inside
`extension/android/jni`; the moment another target picks the `.cpp` up as an
exported source, the include fails. This exports the missing files and
switches both includes to the full `<executorch/extension/android/jni/...>`
path used everywhere else in the tree.

Motivating case: building one `libexecutorch.so` that bundles the JNI bridge,
the runtime, and both the Vulkan and XNNPACK backends. Android's linker only
runs static initializers for libraries reached through an explicit
`System.loadLibrary`, so splitting the backends across several `.so` files
leaves their `REGISTER_BACKEND` globals unexecuted and the backends invisible
at runtime. Composing everything into a single `.so` requires reusing these
JNI sources from another package, which is what the include change enables.

No behavior change to any existing target.

Differential Revision: D118236328
---
 extension/android/jni/BUCK           | 16 ++++++++++++++++
 extension/android/jni/jni_helper.cpp |  2 +-
 extension/android/jni/log.cpp        |  2 +-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/extension/android/jni/BUCK b/extension/android/jni/BUCK
index 1b3e63002f8..1c7e714b145 100644
--- a/extension/android/jni/BUCK
+++ b/extension/android/jni/BUCK
@@ -146,6 +146,22 @@ runtime.export_file(
     name = "jni_helper.cpp",
 )
 
+runtime.export_file(
+    name = "log.cpp",
+)
+
+runtime.export_file(
+    name = "jni_helper.h",
+)
+
+runtime.export_file(
+    name = "log.h",
+)
+
+runtime.export_file(
+    name = "jni_layer_constants.h",
+)
+
 runtime.cxx_library(
     name = "jni_headers",
     exported_headers = [
diff --git a/extension/android/jni/jni_helper.cpp b/extension/android/jni/jni_helper.cpp
index f7c9c4abb74..55bca45a717 100644
--- a/extension/android/jni/jni_helper.cpp
+++ b/extension/android/jni/jni_helper.cpp
@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#include "jni_helper.h"
+#include <executorch/extension/android/jni/jni_helper.h>
 
 namespace executorch::jni_helper {
 
diff --git a/extension/android/jni/log.cpp b/extension/android/jni/log.cpp
index 663198e1271..04deb3ecfd7 100644
--- a/extension/android/jni/log.cpp
+++ b/extension/android/jni/log.cpp
@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-#include "log.h"
+#include <executorch/extension/android/jni/log.h>
 
 #ifdef __ANDROID__