Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2003, 2010, 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.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "runtime/frame.inline.hpp"

 #include "thread_solaris.inline.hpp"

 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is

 // currently interrupted by SIGPROF

 //

 // NOTE: On Solaris, register windows are flushed in the signal handler

 // except for possibly the top frame.

 //

 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,

   void* ucontext, bool isInJava) {

   assert(Thread::current() == this, "caller must be current thread");

   assert(this->is_Java_thread(), "must be JavaThread");

   JavaThread* jt = (JavaThread *)this;

   if (!isInJava) {

     // make_walkable flushes register windows and grabs last_Java_pc

     // which can not be done if the ucontext sp matches last_Java_sp

     // stack walking utilities assume last_Java_pc set if marked flushed

     jt->frame_anchor()->make_walkable(jt);

   }

   // If we have a walkable last_Java_frame, then we should use it

   // even if isInJava == true. It should be more reliable than

   // ucontext info.

   if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {

     *fr_addr = jt->pd_last_frame();

     return true;

   }

   ucontext_t* uc = (ucontext_t*) ucontext;

   // At this point, we don't have a walkable last_Java_frame, so

   // we try to glean some information out of the ucontext.

   intptr_t* ret_sp;

   ExtendedPC addr = os::Solaris::fetch_frame_from_ucontext(this, uc,

     &ret_sp, NULL /* ret_fp only used on Solaris X86 */);

   if (addr.pc() == NULL || ret_sp == NULL) {

     // ucontext wasn't useful

     return false;

   }

   frame ret_frame(ret_sp, frame::unpatchable, addr.pc());

   // we were running Java code when SIGPROF came in

   if (isInJava) {

     // If the frame we got is safe then it is most certainly valid

     if (ret_frame.safe_for_sender(jt)) {

       *fr_addr = ret_frame;

       return true;

     }

     // If it isn't safe then we can try several things to try and get

     // a good starting point.

     //

     // On sparc the frames are almost certainly walkable in the sense

     // of sp/fp linkages. However because of recycling of windows if

     // a piece of code does multiple save's where the initial save creates

     // a real frame with a return pc and the succeeding save's are used to

     // simply get free registers and have no real pc then the pc linkage on these

     // "inner" temporary frames will be bogus.

     // Since there is in general only a nesting level like

     // this one deep in general we'll try and unwind such an "inner" frame

     // here ourselves and see if it makes sense

     frame unwind_frame(ret_frame.fp(), frame::unpatchable, addr.pc());

     if (unwind_frame.safe_for_sender(jt)) {

       *fr_addr = unwind_frame;

       return true;

     }

     // Well that didn't work. Most likely we're toast on this tick

     // The previous code would try this. I think it is dubious in light

     // of changes to safe_for_sender and the unwind trick above but

     // if it gets us a safe frame who wants to argue.

     // If we have a last_Java_sp, then the SIGPROF signal caught us

     // right when we were transitioning from _thread_in_Java to a new

     // JavaThreadState. We use last_Java_sp instead of the sp from

     // the ucontext since it should be more reliable.

     if (jt->has_last_Java_frame()) {

       ret_sp = jt->last_Java_sp();

       frame ret_frame2(ret_sp, frame::unpatchable, addr.pc());

       if (ret_frame2.safe_for_sender(jt)) {

         *fr_addr = ret_frame2;

         return true;

       }

     }

     // This is the best we can do. We will only be able to decode the top frame

     *fr_addr = ret_frame;

     return true;

   }

   // At this point, we know we weren't running Java code. We might

   // have a last_Java_sp, but we don't have a walkable frame.

   // However, we might still be able to construct something useful

   // if the thread was running native code.

   if (jt->has_last_Java_frame()) {

     assert(!jt->frame_anchor()->walkable(), "case covered above");

     frame ret_frame(jt->last_Java_sp(), frame::unpatchable, addr.pc());

     *fr_addr = ret_frame;

     return true;

   }

   // nothing else to try but what we found initially

   *fr_addr = ret_frame;

   return true;

 }

 void JavaThread::cache_global_variables() { }