view src/share/vm/prims/jvmtiTrace.cpp @ 1716:be3f9c242c9d

6948538: CMS: BOT walkers can fall into object allocation and initialization cracks Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode. Reviewed-by: chrisphi, johnc, poonam
author ysr
date Mon, 16 Aug 2010 15:58:42 -0700
parents c18cbe5936b8
children f95d63e2154a
line wrap: on
line source

/*
 * Copyright (c) 2003, 2008, 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 "incls/_precompiled.incl"
# include "incls/_jvmtiTrace.cpp.incl"

//
// class JvmtiTrace
//
// Support for JVMTI tracing code
//
// ------------
// Usage:
//    -XX:TraceJVMTI=DESC,DESC,DESC
//
//    DESC is   DOMAIN ACTION KIND
//
//    DOMAIN is function name
//              event name
//              "all" (all functions and events)
//              "func" (all functions except boring)
//              "allfunc" (all functions)
//              "event" (all events)
//              "ec" (event controller)
//
//    ACTION is "+" (add)
//              "-" (remove)
//
//    KIND is
//     for func
//              "i" (input params)
//              "e" (error returns)
//              "o" (output)
//     for event
//              "t" (event triggered aka posted)
//              "s" (event sent)
//
// Example:
//            -XX:TraceJVMTI=ec+,GetCallerFrame+ie,Breakpoint+s

#ifdef JVMTI_TRACE

bool JvmtiTrace::_initialized = false;
bool JvmtiTrace::_on = false;
bool JvmtiTrace::_trace_event_controller = false;

void JvmtiTrace::initialize() {
  if (_initialized) {
    return;
  }
  SafeResourceMark rm;

  const char *very_end;
  const char *curr;
  if (TraceJVMTI != NULL) {
    curr = TraceJVMTI;
  } else {
    curr = "";  // hack in fixed tracing here
  }
  very_end = curr + strlen(curr);
  while (curr < very_end) {
    const char *curr_end = strchr(curr, ',');
    if (curr_end == NULL) {
      curr_end = very_end;
    }
    const char *op_pos = strchr(curr, '+');
    const char *minus_pos = strchr(curr, '-');
    if (minus_pos != NULL && (minus_pos < op_pos || op_pos == NULL)) {
      op_pos = minus_pos;
    }
    char op;
    const char *flags = op_pos + 1;
    const char *flags_end = curr_end;
    if (op_pos == NULL || op_pos > curr_end) {
      flags = "ies";
      flags_end = flags + strlen(flags);
      op_pos = curr_end;
      op = '+';
    } else {
      op = *op_pos;
    }
    jbyte bits = 0;
    for (; flags < flags_end; ++flags) {
      switch (*flags) {
      case 'i':
        bits |= SHOW_IN;
        break;
      case 'I':
        bits |= SHOW_IN_DETAIL;
        break;
      case 'e':
        bits |= SHOW_ERROR;
        break;
      case 'o':
        bits |= SHOW_OUT;
        break;
      case 'O':
        bits |= SHOW_OUT_DETAIL;
        break;
      case 't':
        bits |= SHOW_EVENT_TRIGGER;
        break;
      case 's':
        bits |= SHOW_EVENT_SENT;
        break;
      default:
        tty->print_cr("Invalid trace flag '%c'", *flags);
        break;
      }
    }
    const int FUNC = 1;
    const int EXCLUDE  = 2;
    const int ALL_FUNC = 4;
    const int EVENT = 8;
    const int ALL_EVENT = 16;
    int domain = 0;
    size_t len = op_pos - curr;
    if (op_pos == curr) {
      domain = ALL_FUNC | FUNC | ALL_EVENT | EVENT | EXCLUDE;
    } else if (len==3 && strncmp(curr, "all", 3)==0) {
      domain = ALL_FUNC | FUNC | ALL_EVENT | EVENT;
    } else if (len==7 && strncmp(curr, "allfunc", 7)==0) {
      domain = ALL_FUNC | FUNC;
    } else if (len==4 && strncmp(curr, "func", 4)==0) {
      domain = ALL_FUNC | FUNC | EXCLUDE;
    } else if (len==8 && strncmp(curr, "allevent", 8)==0) {
      domain = ALL_EVENT | EVENT;
    } else if (len==5 && strncmp(curr, "event", 5)==0) {
      domain = ALL_EVENT | EVENT;
    } else if (len==2 && strncmp(curr, "ec", 2)==0) {
      _trace_event_controller = true;
      tty->print_cr("JVMTI Tracing the event controller");
    } else {
      domain = FUNC | EVENT;  // go searching
    }

    int exclude_index = 0;
    if (domain & FUNC) {
      if (domain & ALL_FUNC) {
        if (domain & EXCLUDE) {
          tty->print("JVMTI Tracing all significant functions");
        } else {
          tty->print_cr("JVMTI Tracing all functions");
        }
      }
      for (int i = 0; i <= _max_function_index; ++i) {
        if (domain & EXCLUDE && i == _exclude_functions[exclude_index]) {
          ++exclude_index;
        } else {
          bool do_op = false;
          if (domain & ALL_FUNC) {
            do_op = true;
          } else {
            const char *fname = function_name(i);
            if (fname != NULL) {
              size_t fnlen = strlen(fname);
              if (len==fnlen && strncmp(curr, fname, fnlen)==0) {
                tty->print_cr("JVMTI Tracing the function: %s", fname);
                do_op = true;
              }
            }
          }
          if (do_op) {
            if (op == '+') {
              _trace_flags[i] |= bits;
            } else {
              _trace_flags[i] &= ~bits;
            }
            _on = true;
          }
        }
      }
    }
    if (domain & EVENT) {
      if (domain & ALL_EVENT) {
        tty->print_cr("JVMTI Tracing all events");
      }
      for (int i = 0; i <= _max_event_index; ++i) {
        bool do_op = false;
        if (domain & ALL_EVENT) {
          do_op = true;
        } else {
          const char *ename = event_name(i);
          if (ename != NULL) {
            size_t evtlen = strlen(ename);
            if (len==evtlen && strncmp(curr, ename, evtlen)==0) {
              tty->print_cr("JVMTI Tracing the event: %s", ename);
              do_op = true;
            }
          }
        }
        if (do_op) {
          if (op == '+') {
            _event_trace_flags[i] |= bits;
          } else {
            _event_trace_flags[i] &= ~bits;
          }
          _on = true;
        }
      }
    }
    if (!_on && (domain & (FUNC|EVENT))) {
      tty->print_cr("JVMTI Trace domain not found");
    }
    curr = curr_end + 1;
  }
  _initialized = true;
}


void JvmtiTrace::shutdown() {
  int i;
  _on = false;
  _trace_event_controller = false;
  for (i = 0; i <= _max_function_index; ++i) {
    _trace_flags[i] = 0;
  }
  for (i = 0; i <= _max_event_index; ++i) {
    _event_trace_flags[i] = 0;
  }
}


const char* JvmtiTrace::enum_name(const char** names, const jint* values, jint value) {
  for (int index = 0; names[index] != 0; ++index) {
    if (values[index] == value) {
      return names[index];
    }
  }
  return "*INVALID-ENUM-VALUE*";
}


// return a valid string no matter what state the thread is in
const char *JvmtiTrace::safe_get_thread_name(Thread *thread) {
  if (thread == NULL) {
    return "NULL";
  }
  if (!thread->is_Java_thread()) {
    return thread->name();
  }
  JavaThread *java_thread = (JavaThread *)thread;
  oop threadObj = java_thread->threadObj();
  if (threadObj == NULL) {
    return "NULL";
  }
  typeArrayOop name = java_lang_Thread::name(threadObj);
  if (name == NULL) {
    return "<NOT FILLED IN>";
  }
  return UNICODE::as_utf8((jchar*) name->base(T_CHAR), name->length());
}


// return the name of the current thread
const char *JvmtiTrace::safe_get_current_thread_name() {
  if (JvmtiEnv::is_vm_live()) {
    return JvmtiTrace::safe_get_thread_name(Thread::current());
  } else {
    return "VM not live";
  }
}

// return a valid string no matter what the state of k_mirror
const char * JvmtiTrace::get_class_name(oop k_mirror) {
  if (java_lang_Class::is_primitive(k_mirror)) {
    return "primitive";
  }
  klassOop k_oop = java_lang_Class::as_klassOop(k_mirror);
  if (k_oop == NULL) {
    return "INVALID";
  }
  return Klass::cast(k_oop)->external_name();
}

#endif /*JVMTI_TRACE */