view src/share/vm/runtime/vframe_hp.hpp @ 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
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/*
 * Copyright (c) 1997, 2009, 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.
 *
 */

class compiledVFrame: public javaVFrame {
 public:
  // JVM state
  methodOop                    method()             const;
  int                          bci()                const;
  bool                         should_reexecute()   const;
  StackValueCollection*        locals()             const;
  StackValueCollection*        expressions()        const;
  GrowableArray<MonitorInfo*>* monitors()           const;

  void set_locals(StackValueCollection* values) const;

  // Virtuals defined in vframe
  bool is_compiled_frame() const { return true; }
  vframe* sender() const;
  bool is_top() const;

  // Casting
  static compiledVFrame* cast(vframe* vf) {
    assert(vf == NULL || vf->is_compiled_frame(), "must be compiled frame");
    return (compiledVFrame*) vf;
  }

 public:
  // Constructors
  compiledVFrame(const frame* fr, const RegisterMap* reg_map, JavaThread* thread, nmethod* nm);

  // Update a local in a compiled frame. Update happens when deopt occurs
  void update_local(BasicType type, int index, jvalue value);

  // Returns the active nmethod
  nmethod*  code() const;

  // Returns the scopeDesc
  ScopeDesc* scope() const { return _scope; }

  // Returns SynchronizationEntryBCI or bci() (used for synchronization)
  int raw_bci() const;

 protected:
  ScopeDesc* _scope;


  //StackValue resolve(ScopeValue* sv) const;
  BasicLock* resolve_monitor_lock(Location location) const;
  StackValue *create_stack_value(ScopeValue *sv) const;

 private:
  compiledVFrame(const frame* fr, const RegisterMap* reg_map, JavaThread* thread, ScopeDesc* scope);

#ifndef PRODUCT
 public:
  void verify() const;
#endif
};

// In order to implement set_locals for compiled vframes we must
// store updated locals in a data structure that contains enough
// information to recognize equality with a vframe and to store
// any updated locals.

class jvmtiDeferredLocalVariable;
class jvmtiDeferredLocalVariableSet : public CHeapObj {
private:

  methodOop _method;           // must be GC'd
  int       _bci;
  intptr_t* _id;
  GrowableArray<jvmtiDeferredLocalVariable*>* _locals;

 public:
  // JVM state
  methodOop                         method()         const  { return _method; }
  int                               bci()            const  { return _bci; }
  intptr_t*                         id()             const  { return _id; }
  GrowableArray<jvmtiDeferredLocalVariable*>* locals()         const  { return _locals; }
  void                              set_local_at(int idx, BasicType typ, jvalue val);

  // Does the vframe match this jvmtiDeferredLocalVariableSet
  bool                              matches(vframe* vf);
  // GC
  void                              oops_do(OopClosure* f);

  // constructor
  jvmtiDeferredLocalVariableSet(methodOop method, int bci, intptr_t* id);

  // destructor
  ~jvmtiDeferredLocalVariableSet();


};

class jvmtiDeferredLocalVariable : public CHeapObj {
  public:

    jvmtiDeferredLocalVariable(int index, BasicType type, jvalue value);

    BasicType type(void)                   { return _type; }
    int index(void)                        { return _index; }
    jvalue value(void)                     { return _value; }
    // Only mutator is for value as only it can change
    void set_value(jvalue value)           { _value = value; }
    // For gc
    oop* oop_addr(void)                    { return (oop*) &_value.l; }

  private:

    BasicType         _type;
    jvalue            _value;
    int               _index;

};