1 /*
   2  * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "memory/metaspaceShared.hpp"
  27 #include "runtime/frame.inline.hpp"
  28 #include "runtime/thread.inline.hpp"
  29 
  30 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
  31 // currently interrupted by SIGPROF
  32 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
  33   void* ucontext, bool isInJava) {
  34 
  35   assert(Thread::current() == this, "caller must be current thread");
  36   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  37 }
  38 
  39 bool JavaThread::pd_get_top_frame_for_profiling(frame* fr_addr, void* ucontext, bool isInJava) {
  40   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  41 }
  42 
  43 bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  44   assert(this->is_Java_thread(), "must be JavaThread");
  45   JavaThread* jt = (JavaThread *)this;
  46 
  47   // If we have a last_Java_frame, then we should use it even if
  48   // isInJava == true.  It should be more reliable than ucontext info.
  49   if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
  50     *fr_addr = jt->pd_last_frame();
  51     return true;
  52   }
  53 
  54   // At this point, we don't have a last_Java_frame, so
  55   // we try to glean some information out of the ucontext
  56   // if we were running Java code when SIGPROF came in.
  57   if (isInJava) {
  58     ucontext_t* uc = (ucontext_t*) ucontext;
  59 
  60     intptr_t* ret_fp;
  61     intptr_t* ret_sp;
  62     ExtendedPC addr = os::Linux::fetch_frame_from_ucontext(this, uc,
  63       &ret_sp, &ret_fp);
  64     if (addr.pc() == NULL || ret_sp == NULL ) {
  65       // ucontext wasn't useful
  66       return false;
  67     }
  68 
  69     if (MetaspaceShared::is_in_trampoline_frame(addr.pc())) {
  70       // In the middle of a trampoline call. Bail out for safety.
  71       // This happens rarely so shouldn't affect profiling.
  72       return false;
  73     }
  74 
  75     frame ret_frame(ret_sp, ret_fp, addr.pc());
  76     if (!ret_frame.safe_for_sender(jt)) {
  77 #if COMPILER2_OR_JVMCI
  78       // C2 and JVMCI use ebp as a general register see if NULL fp helps
  79       frame ret_frame2(ret_sp, NULL, addr.pc());
  80       if (!ret_frame2.safe_for_sender(jt)) {
  81         // nothing else to try if the frame isn't good
  82         return false;
  83       }
  84       ret_frame = ret_frame2;
  85 #else
  86       // nothing else to try if the frame isn't good
  87       return false;
  88 #endif // COMPILER2_OR_JVMCI
  89     }
  90     *fr_addr = ret_frame;
  91     return true;
  92   }
  93 
  94   // nothing else to try
  95   return false;
  96 }
  97 
  98 void JavaThread::cache_global_variables() { }
  99