src/hotspot/share/code/nmethod.cpp

rev 48402 : 8193927: Optimize scanning code for oops.
Reviewed-by: simonis, mdoerr, aph

*** 1,7 ****
  /*
!  * Copyright (c) 1997, 2017, Oracle and/or its affiliates. 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
   * published by the Free Software Foundation.
--- 1,7 ----
  /*
!  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. 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
   * published by the Free Software Foundation.
*** 1483,1493 ****
    return false;
  }
  
  bool nmethod::do_unloading_oops(address low_boundary, BoolObjectClosure* is_alive, bool unloading_occurred) {
    // Compiled code
!   {
    RelocIterator iter(this, low_boundary);
    while (iter.next()) {
      if (iter.type() == relocInfo::oop_type) {
        if (unload_if_dead_at(&iter, is_alive, unloading_occurred)) {
          return true;
--- 1483,1495 ----
    return false;
  }
  
  bool nmethod::do_unloading_oops(address low_boundary, BoolObjectClosure* is_alive, bool unloading_occurred) {
    // Compiled code
! 
!   // Prevent extra code cache walk for platforms that don't have immediate oops.
!   if (relocInfo::mustIterateImmediateOopsInCode()) {
      RelocIterator iter(this, low_boundary);
      while (iter.next()) {
        if (iter.type() == relocInfo::oop_type) {
          if (unload_if_dead_at(&iter, is_alive, unloading_occurred)) {
            return true;
*** 1582,1591 ****
--- 1584,1595 ----
      low_boundary += NativeJump::instruction_size;
      // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.
      // (See comment above.)
    }
  
+   // Prevent extra code cache walk for platforms that don't have immediate oops.
+   if (relocInfo::mustIterateImmediateOopsInCode()) {
      RelocIterator iter(this, low_boundary);
  
      while (iter.next()) {
        if (iter.type() == relocInfo::oop_type ) {
          oop_Relocation* r = iter.oop_reloc();
*** 1597,1606 ****
--- 1601,1611 ----
          if (r->oop_is_immediate() && r->oop_value() != NULL) {
            f->do_oop(r->oop_addr());
          }
        }
      }
+   }
  
    // Scopes
    // This includes oop constants not inlined in the code stream.
    for (oop* p = oops_begin(); p < oops_end(); p++) {
      if (*p == Universe::non_oop_word())  continue;  // skip non-oops