1 /*
   2  * Copyright (c) 2012, 2018, 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 "code/debugInfoRec.hpp"
  27 #include "code/nmethod.hpp"
  28 #include "code/pcDesc.hpp"
  29 #include "jfr/periodic/sampling/jfrCallTrace.hpp"
  30 #include "oops/method.hpp"
  31 #include "runtime/javaCalls.hpp"
  32 #include "runtime/frame.inline.hpp"
  33 #include "runtime/registerMap.hpp"
  34 #include "runtime/thread.inline.hpp"
  35 
  36 bool JfrGetCallTrace::find_top_frame(frame& top_frame, Method** method, frame& first_frame) {
  37   assert(top_frame.cb() != NULL, "invariant");
  38   RegisterMap map(_thread, false);
  39   frame candidate = top_frame;
  40   for (int i = 0; i < MaxJavaStackTraceDepth * 2; ++i) {
  41     if (candidate.is_entry_frame()) {
  42       JavaCallWrapper *jcw = candidate.entry_frame_call_wrapper_if_safe(_thread);
  43       if (jcw == NULL || jcw->is_first_frame()) {
  44         return false;
  45       }
  46     }
  47 
  48     if (candidate.is_interpreted_frame()) {
  49       JavaThreadState state = _thread->thread_state();
  50       const bool known_valid = (state == _thread_in_native || state == _thread_in_vm || state == _thread_blocked);
  51       if (known_valid || candidate.is_interpreted_frame_valid(_thread)) {
  52         Method* im = candidate.interpreter_frame_method();
  53         if (known_valid && !im->is_valid_method()) {
  54           return false;
  55         }
  56         *method = im;
  57         first_frame = candidate;
  58         return true;
  59       }
  60     }
  61 
  62     if (candidate.cb()->is_nmethod()) {
  63       // first check to make sure that we have a sane stack,
  64       // the PC is actually inside the code part of the codeBlob,
  65       // and we are past is_frame_complete_at (stack has been setup)
  66       if (!candidate.safe_for_sender(_thread)) {
  67         return false;
  68       }
  69       nmethod* nm = (nmethod*)candidate.cb();
  70       *method = nm->method();
  71 
  72       if (_in_java) {
  73         PcDesc* pc_desc = nm->pc_desc_near(candidate.pc() + 1);
  74         if (pc_desc == NULL || pc_desc->scope_decode_offset() == DebugInformationRecorder::serialized_null) {
  75           return false;
  76         }
  77         candidate.set_pc(pc_desc->real_pc(nm));
  78         assert(nm->pc_desc_at(candidate.pc()) != NULL, "invalid pc");
  79       }
  80       first_frame = candidate;
  81       return true;
  82     }
  83 
  84     if (!candidate.safe_for_sender(_thread) ||
  85       candidate.is_stub_frame() ||
  86       candidate.cb()->frame_size() <= 0) {
  87       return false;
  88     }
  89 
  90     candidate = candidate.sender(&map);
  91     if (candidate.cb() == NULL) {
  92       return false;
  93     }
  94   }
  95   return false;
  96 }
  97 
  98 bool JfrGetCallTrace::get_topframe(void* ucontext, frame& topframe) {
  99   if (!_thread->pd_get_top_frame_for_profiling(&topframe, ucontext, _in_java)) {
 100     return false;
 101   }
 102 
 103   if (topframe.cb() == NULL) {
 104     return false;
 105   }
 106 
 107   frame first_java_frame;
 108   Method* method = NULL;
 109   if (find_top_frame(topframe, &method, first_java_frame)) {
 110     if (method == NULL) {
 111       return false;
 112     }
 113     topframe = first_java_frame;
 114     return true;
 115   }
 116   return false;
 117 }