/*

 * Copyright 1998-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

//** The DebugInformationRecorder collects debugging information

//   for a compiled method.

//   Debugging information is used for:

//   - garbage collecting compiled frames

//   - stack tracing across compiled frames

//   - deoptimizating compiled frames

//

//   The implementation requires the compiler to use the recorder

//   in the following order:

//   1) Describe debug information for safepoints at increasing addresses.

//      a) Add safepoint entry (use add_safepoint or add_non_safepoint)

//      b) Describe scopes for that safepoint

//         - create locals if needed (use create_scope_values)

//         - create expressions if needed (use create_scope_values)

//         - create monitor stack if needed (use create_monitor_values)

//         - describe scope (use describe_scope)

//         "repeat last four steps for all scopes"

//         "outer most scope first and inner most scope last"

//         NB: nodes from create_scope_values and create_locations

//             can be reused for simple sharing.

//         - mark the end of the scopes (end_safepoint or end_non_safepoint)

//   2) Use oop_size, data_size, pcs_size to create the nmethod and

//      finally migrate the debugging information into the nmethod

//      by calling copy_to.

class DebugToken; // Opaque datatype for stored:

                  //  - GrowableArray<ScopeValue*>

                  //  - GrowableArray<MonitorValue*>

// Alias for InvocationEntryBci.

// Both constants are used for a pseudo-BCI which refers

// to the state just _before_ a method is entered.

// SynchronizationEntryBCI is used where the emphasis

// is on the implicit monitorenter of a synchronized method.

const int SynchronizationEntryBCI = InvocationEntryBci;

class DIR_Chunk; // private class, a nugget of collected information

class DebugInformationRecorder: public ResourceObj {

 public:

  // constructor

  DebugInformationRecorder(OopRecorder* oop_recorder);

  // adds an oopmap at a specific offset

  void add_oopmap(int pc_offset, OopMap* map);

  // adds a jvm mapping at pc-offset, for a safepoint only

  void add_safepoint(int pc_offset, OopMap* map);

  // adds a jvm mapping at pc-offset, for a non-safepoint (profile point)

  void add_non_safepoint(int pc_offset);

  // Describes debugging information for a scope at the given pc_offset.

  // Calls must be in non-decreasing order of pc_offset.

  // If there are several calls at a single pc_offset,

  // then they occur in the same order as they were performed by the JVM,

  // with the most recent (innermost) call being described last.

  // For a safepoint, the pc_offset must have been mentioned

  // previously by add_safepoint.

  // Otherwise, the pc_offset must have been mentioned previously

  // by add_non_safepoint, and the locals, expressions, and monitors

  // must all be null.

  void describe_scope(int         pc_offset,

                      ciMethod*   method,

                      int         bci,

                      bool        reexecute,

                      DebugToken* locals      = NULL,

                      DebugToken* expressions = NULL,

                      DebugToken* monitors    = NULL);

  void dump_object_pool(GrowableArray<ScopeValue*>* objects);

  // This call must follow every add_safepoint,

  // after any intervening describe_scope calls.

  void end_safepoint(int pc_offset)      { end_scopes(pc_offset, true); }

  void end_non_safepoint(int pc_offset)  { end_scopes(pc_offset, false); }

  // helper fuctions for describe_scope to enable sharing

  DebugToken* create_scope_values(GrowableArray<ScopeValue*>* values);

  DebugToken* create_monitor_values(GrowableArray<MonitorValue*>* monitors);

  // returns the size of the generated scopeDescs.

  int data_size();

  int pcs_size();

  int oop_size() { return oop_recorder()->oop_size(); }

  // copy the generated debugging information to nmethod

  void copy_to(nmethod* nm);

  // verifies the debug information

  void verify(const nmethod* code);

  static void print_statistics() PRODUCT_RETURN;

  // Method for setting oopmaps to temporarily preserve old handling of oopmaps

  OopMapSet *_oopmaps;

  void set_oopmaps(OopMapSet *oopmaps) { _oopmaps = oopmaps; }

  OopRecorder* oop_recorder() { return _oop_recorder; }

  int last_pc_offset() { return last_pc()->pc_offset(); }

  bool recording_non_safepoints() { return _recording_non_safepoints; }

 private:

  friend class ScopeDesc;

  friend class vframeStreamCommon;

  friend class DIR_Chunk;

  // True if we are recording non-safepoint scopes.

  // This flag is set if DebugNonSafepoints is true, or if

  // JVMTI post_compiled_method_load events are enabled.

  const bool _recording_non_safepoints;

  DebugInfoWriteStream* _stream;

  DebugInfoWriteStream* stream() const { return _stream; }

  OopRecorder* _oop_recorder;

  // Scopes that have been described so far.

  GrowableArray<DIR_Chunk*>* _all_chunks;

  GrowableArray<DIR_Chunk*>* _shared_chunks;

  DIR_Chunk* _next_chunk;

  DIR_Chunk* _next_chunk_limit;

#ifdef ASSERT

  enum { rs_null, rs_safepoint, rs_non_safepoint };

  int _recording_state;

#endif

  PcDesc* _pcs;

  int     _pcs_size;

  int     _pcs_length;

  // Note:  Would use GrowableArray<PcDesc>, but structs are not supported.

  // PC of most recent real safepoint before the current one,

  // updated after end_scopes.

  int _prev_safepoint_pc;

  PcDesc* last_pc() {

    guarantee(_pcs_length > 0, "a safepoint must be declared already");

    return &_pcs[_pcs_length-1];

  }

  PcDesc* prev_pc() {

    guarantee(_pcs_length > 1, "a safepoint must be declared already");

    return &_pcs[_pcs_length-2];

  }

  void add_new_pc_offset(int pc_offset);

  void end_scopes(int pc_offset, bool is_safepoint);

  int  serialize_monitor_values(GrowableArray<MonitorValue*>* monitors);

  int  serialize_scope_values(GrowableArray<ScopeValue*>* values);

  int  find_sharable_decode_offset(int stream_offset);

 public:

  enum { serialized_null = 0 };

};