src/cpu/aarch64/vm/sharedRuntime_aarch64.cpp

rev 12692 : 8176100: [REDO][REDO] G1 Needs pre barrier on dereference of weak JNI handles
Reviewed-by:

*** 1,7 ****
  /*
!  * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2014, 2015, Red Hat Inc. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
--- 1,7 ----
  /*
!  * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2014, 2015, Red Hat Inc. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
*** 2050,2066 ****
      __ bind(dtrace_method_exit_done);
    }
  
    __ reset_last_Java_frame(false);
  
!   // Unpack oop result
    if (ret_type == T_OBJECT || ret_type == T_ARRAY) {
!       Label L;
!       __ cbz(r0, L);
        __ ldr(r0, Address(r0, 0));
-       __ bind(L);
        __ verify_oop(r0);
    }
  
    if (CheckJNICalls) {
      // clear_pending_jni_exception_check
      __ str(zr, Address(rthread, JavaThread::pending_jni_exception_check_fn_offset()));
--- 2050,2084 ----
      __ bind(dtrace_method_exit_done);
    }
  
    __ reset_last_Java_frame(false);
  
!   // Unbox oop result, e.g. JNIHandles::resolve result.
    if (ret_type == T_OBJECT || ret_type == T_ARRAY) {
!     Label done, not_weak;
!     __ cbz(r0, done);           // Use NULL as-is.
!     STATIC_ASSERT(JNIHandles::weak_tag_mask == 1u);
!     __ tbz(r0, 0, not_weak);    // Test for jweak tag.
!     // Resolve jweak.
!     __ ldr(r0, Address(r0, -JNIHandles::weak_tag_value));
!     __ verify_oop(r0);
! #if INCLUDE_ALL_GCS
!     if (UseG1GC) {
!       __ g1_write_barrier_pre(noreg /* obj */,
!                               r0 /* pre_val */,
!                               rthread /* thread */,
!                               rscratch1 /* tmp */,
!                               true /* tosca_live */,
!                               true /* expand_call */);
!     }
! #endif // INCLUDE_ALL_GCS
!     __ b(done);
!     __ bind(not_weak);
!     // Resolve (untagged) jobject.
      __ ldr(r0, Address(r0, 0));
      __ verify_oop(r0);
+     __ bind(done);
    }
  
    if (CheckJNICalls) {
      // clear_pending_jni_exception_check
      __ str(zr, Address(rthread, JavaThread::pending_jni_exception_check_fn_offset()));