8254842: [JVMCI] copy thread name when attaching libgraal thread to HotSpot

Reviewed-by: kvn, never

Author: Doug Simon

src/hotspot/share/jvmci/jvmciCompilerToVM.cpp

@@ -2349,13 +2349,25 @@ C2V_VMENTRY_PREFIX(jlong, getCurrentJavaThread, (JNIEnv* env, jobject c2vm))
   return (jlong) p2i(thread);
 C2V_END
 
-C2V_VMENTRY_PREFIX(jboolean, attachCurrentThread, (JNIEnv* env, jobject c2vm, jboolean as_daemon))
+C2V_VMENTRY_PREFIX(jboolean, attachCurrentThread, (JNIEnv* env, jobject c2vm, jbyteArray name, jboolean as_daemon))
   if (thread == NULL) {
     // Called from unattached JVMCI shared library thread
+    guarantee(name != NULL, "libjvmci caller must pass non-null name");
+
     extern struct JavaVM_ main_vm;
     JNIEnv* hotspotEnv;
-    jint res = as_daemon ? main_vm.AttachCurrentThreadAsDaemon((void**) &hotspotEnv, NULL) :
-                           main_vm.AttachCurrentThread((void**) &hotspotEnv, NULL);
+
+    int name_len = env->GetArrayLength(name);
+    char name_buf[64]; // Cannot use Resource heap as it requires a current thread
+    int to_copy = MIN2(name_len, (int) sizeof(name_buf) - 1);
+    env->GetByteArrayRegion(name, 0, to_copy, (jbyte*) name_buf);
+    name_buf[to_copy] = '\0';
+    JavaVMAttachArgs attach_args;
+    attach_args.version = JNI_VERSION_1_2;
+    attach_args.name = name_buf;
+    attach_args.group = NULL;
+    jint res = as_daemon ? main_vm.AttachCurrentThreadAsDaemon((void**) &hotspotEnv, &attach_args) :
+                           main_vm.AttachCurrentThread((void**) &hotspotEnv, &attach_args);
     if (res != JNI_OK) {
       JNI_THROW_("attachCurrentThread", InternalError, err_msg("Trying to attach thread returned %d", res), false);
     }
@@ -2803,7 +2815,7 @@ JNINativeMethod CompilerToVM::methods[] = {
   {CC "registerNativeMethods",                        CC "(" CLASS ")[J",                                                                   FN_PTR(registerNativeMethods)},
   {CC "isCurrentThreadAttached",                      CC "()Z",                                                                             FN_PTR(isCurrentThreadAttached)},
   {CC "getCurrentJavaThread",                         CC "()J",                                                                             FN_PTR(getCurrentJavaThread)},
-  {CC "attachCurrentThread",                          CC "(Z)Z",                                                                            FN_PTR(attachCurrentThread)},
+  {CC "attachCurrentThread",                          CC "([BZ)Z",                                                                          FN_PTR(attachCurrentThread)},
   {CC "detachCurrentThread",                          CC "()V",                                                                             FN_PTR(detachCurrentThread)},
   {CC "translate",                                    CC "(" OBJECT ")J",                                                                   FN_PTR(translate)},
   {CC "unhand",                                       CC "(J)" OBJECT,                                                                      FN_PTR(unhand)},

src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/CompilerToVM.java

@@ -977,9 +977,10 @@ HotSpotResolvedObjectTypeImpl getResolvedJavaType(long displacement, boolean com
     native long getCurrentJavaThread();
 
     /**
+     * @param name name of current thread if in a native image otherwise {@code null}
      * @see HotSpotJVMCIRuntime#attachCurrentThread
      */
-    native boolean attachCurrentThread(boolean asDaemon);
+    native boolean attachCurrentThread(byte[] name, boolean asDaemon);
 
     /**
      * @see HotSpotJVMCIRuntime#detachCurrentThread()

src/jdk.internal.vm.ci/share/classes/jdk.vm.ci.hotspot/src/jdk/vm/ci/hotspot/HotSpotJVMCIRuntime.java

@@ -1117,7 +1117,8 @@ public long getCurrentJavaThread() {
      *             the length of the array returned by {@link #registerNativeMethods}
      */
     public boolean attachCurrentThread(boolean asDaemon) {
-        return compilerToVm.attachCurrentThread(asDaemon);
+        byte[] name = IS_IN_NATIVE_IMAGE ? Thread.currentThread().getName().getBytes() : null;
+        return compilerToVm.attachCurrentThread(name, asDaemon);
     }
 
     /**