Reinitialized the com.google.protobuf.UnsafeUtil class at runtime

Also fix the Unsafe accessor.
Fix quarkusio#30293.

This has been tested on GraalVM CE and EE.

extensions/grpc-common/deployment/src/main/java/io/quarkus/grpc/common/deployment/GrpcCommonProcessor.java

@@ -75,7 +75,8 @@ NativeImageConfigBuildItem nativeImageConfiguration() {
                 .addRuntimeInitializedClass("io.grpc.netty.Utils")
                 .addRuntimeInitializedClass("io.grpc.netty.NettyServerBuilder")
                 .addRuntimeInitializedClass("io.grpc.netty.NettyChannelBuilder")
-                .addRuntimeInitializedClass("io.grpc.internal.RetriableStream");
+                .addRuntimeInitializedClass("io.grpc.internal.RetriableStream")
+                .addRuntimeReinitializedClass("com.google.protobuf.UnsafeUtil");
         return builder.build();
     }
 

extensions/grpc-common/runtime/src/main/java/io/quarkus/grpc/common/runtime/graal/GrpcSubstitutions.java

@@ -2,6 +2,7 @@
 
 import static io.grpc.InternalServiceProviders.getCandidatesViaHardCoded;
 
+import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
@@ -12,6 +13,8 @@
 import com.oracle.svm.core.annotate.Substitute;
 import com.oracle.svm.core.annotate.TargetClass;
 
+import sun.misc.Unsafe;
+
 @SuppressWarnings("unused")
 @TargetClass(className = "io.grpc.ServiceProviders")
 final class Target_io_grpc_ServiceProviders { // NOSONAR
@@ -79,6 +82,20 @@ interface Target_io_grpc_ServiceProviders_PriorityAccessor<T> { // NOSONAR
     int getPriority(T provider);
 }
 
+@TargetClass(className = "com.google.protobuf.UnsafeUtil")
+final class Target_com_google_protobuf_UnsafeUtil {
+    @Substitute
+    static sun.misc.Unsafe getUnsafe() {
+        try {
+            Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");
+            theUnsafe.setAccessible(true);
+            return (Unsafe) theUnsafe.get(null);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
+
 @SuppressWarnings("unused")
 class GrpcSubstitutions {
 }