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 frame JavaThread::pd_last_frame() {
  31   assert(has_last_Java_frame(), "must have last_Java_sp() when suspended");
  32   vmassert(_anchor.last_Java_pc() != NULL, "not walkable");
  33   return frame(_anchor.last_Java_sp(), _anchor.last_Java_fp(), _anchor.last_Java_pc());
  34 }
  35 
  36 // For Forte Analyzer AsyncGetCallTrace profiling support - thread is
  37 // currently interrupted by SIGPROF
  38 bool JavaThread::pd_get_top_frame_for_signal_handler(frame* fr_addr,
  39   void* ucontext, bool isInJava) {
  40 
  41   assert(Thread::current() == this, "caller must be current thread");
  42   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  43 }
  44 
  45 bool JavaThread::pd_get_top_frame_for_profiling(frame* fr_addr, void* ucontext, bool isInJava) {
  46   return pd_get_top_frame(fr_addr, ucontext, isInJava);
  47 }
  48 
  49 bool JavaThread::pd_get_top_frame(frame* fr_addr, void* ucontext, bool isInJava) {
  50   assert(this->is_Java_thread(), "must be JavaThread");
  51   JavaThread* jt = (JavaThread *)this;
  52 
  53   // If we have a last_Java_frame, then we should use it even if
  54   // isInJava == true.  It should be more reliable than ucontext info.
  55   if (jt->has_last_Java_frame() && jt->frame_anchor()->walkable()) {
  56     *fr_addr = jt->pd_last_frame();
  57     return true;
  58   }
  59 
  60   // At this point, we don't have a last_Java_frame, so
  61   // we try to glean some information out of the ucontext
  62   // if we were running Java code when SIGPROF came in.
  63   if (isInJava) {
  64     ucontext_t* uc = (ucontext_t*) ucontext;
  65 
  66     intptr_t* ret_fp;
  67     intptr_t* ret_sp;
  68     ExtendedPC addr = os::Linux::fetch_frame_from_ucontext(this, uc,
  69       &ret_sp, &ret_fp);
  70     if (addr.pc() == NULL || ret_sp == NULL ) {
  71       // ucontext wasn't useful
  72       return false;
  73     }
  74 
  75     if (MetaspaceShared::is_in_trampoline_frame(addr.pc())) {
  76       // In the middle of a trampoline call. Bail out for safety.
  77       // This happens rarely so shouldn't affect profiling.
  78       return false;
  79     }
  80 
  81     frame ret_frame(ret_sp, ret_fp, addr.pc());
  82     if (!ret_frame.safe_for_sender(jt)) {
  83 #if COMPILER2_OR_JVMCI
  84       // C2 and JVMCI use ebp as a general register see if NULL fp helps
  85       frame ret_frame2(ret_sp, NULL, addr.pc());
  86       if (!ret_frame2.safe_for_sender(jt)) {
  87         // nothing else to try if the frame isn't good
  88         return false;
  89       }
  90       ret_frame = ret_frame2;
  91 #else
  92       // nothing else to try if the frame isn't good
  93       return false;
  94 #endif // COMPILER2_OR_JVMCI
  95     }
  96     *fr_addr = ret_frame;
  97     return true;
  98   }
  99 
 100   // nothing else to try
 101   return false;
 102 }
 103 
 104 void JavaThread::cache_global_variables() { }
 105