/*

 * Copyright (c) 2003, 2012, 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 "precompiled.hpp"

#include "code/codeBlob.hpp"

#include "code/codeCache.hpp"

#include "code/scopeDesc.hpp"

#include "memory/resourceArea.hpp"

#include "oops/oop.inline.hpp"

#include "prims/jvmtiCodeBlobEvents.hpp"

#include "prims/jvmtiExport.hpp"

#include "runtime/handles.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/vmThread.hpp"

// Support class to collect a list of the non-nmethod CodeBlobs in

// the CodeCache.

//

// This class actually creates a list of JvmtiCodeBlobDesc - each JvmtiCodeBlobDesc

// describes a single CodeBlob in the CodeCache. Note that collection is

// done to a static list - this is because CodeCache::blobs_do is defined

// as void CodeCache::blobs_do(void f(CodeBlob* nm)) and hence requires

// a C or static method.

//

// Usage :-

//

// CodeBlobCollector collector;

//

// collector.collect();

// JvmtiCodeBlobDesc* blob = collector.first();

// while (blob != NULL) {

//   :

//   blob = collector.next();

// }

//

class CodeBlobCollector : StackObj {

 private:

  GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs;   // collected blobs

  int _pos;                                         // iterator position

  // used during a collection

  static GrowableArray<JvmtiCodeBlobDesc*>* _global_code_blobs;

  static void do_blob(CodeBlob* cb);

 public:

  CodeBlobCollector() {

    _code_blobs = NULL;

    _pos = -1;

  }

  ~CodeBlobCollector() {

    if (_code_blobs != NULL) {

      for (int i=0; i<_code_blobs->length(); i++) {

        FreeHeap(_code_blobs->at(i));

      }

      delete _code_blobs;

    }

  }

  // collect list of code blobs in the cache

  void collect();

  // iteration support - return first code blob

  JvmtiCodeBlobDesc* first() {

    assert(_code_blobs != NULL, "not collected");

    if (_code_blobs->length() == 0) {

      return NULL;

    }

    _pos = 0;

    return _code_blobs->at(0);

  }

  // iteration support - return next code blob

  JvmtiCodeBlobDesc* next() {

    assert(_pos >= 0, "iteration not started");

    if (_pos+1 >= _code_blobs->length()) {

      return NULL;

    }

    return _code_blobs->at(++_pos);

  }

};

// used during collection

GrowableArray<JvmtiCodeBlobDesc*>* CodeBlobCollector::_global_code_blobs;

// called for each CodeBlob in the CodeCache

//

// This function filters out nmethods as it is only interested in

// other CodeBlobs. This function also filters out CodeBlobs that have

// a duplicate starting address as previous blobs. This is needed to

// handle the case where multiple stubs are generated into a single

// BufferBlob.

void CodeBlobCollector::do_blob(CodeBlob* cb) {

  // ignore nmethods

  if (cb->is_nmethod()) {

    return;

  }

  // check if this starting address has been seen already - the

  // assumption is that stubs are inserted into the list before the

  // enclosing BufferBlobs.

  address addr = cb->code_begin();

  for (int i=0; i<_global_code_blobs->length(); i++) {

    JvmtiCodeBlobDesc* scb = _global_code_blobs->at(i);

    if (addr == scb->code_begin()) {

      return;

    }

  }

  // record the CodeBlob details as a JvmtiCodeBlobDesc

  JvmtiCodeBlobDesc* scb = new JvmtiCodeBlobDesc(cb->name(), cb->code_begin(), cb->code_end());

  _global_code_blobs->append(scb);

}

// collects a list of CodeBlobs in the CodeCache.

//

// The created list is growable array of JvmtiCodeBlobDesc - each one describes

// a CodeBlob. Note that the list is static - this is because CodeBlob::blobs_do

// requires a a C or static function so we can't use an instance function. This

// isn't a problem as the iteration is serial anyway as we need the CodeCache_lock

// to iterate over the code cache.

//

// Note that the CodeBlobs in the CodeCache will include BufferBlobs that may

// contain multiple stubs. As a profiler is interested in the stubs rather than

// the enclosing container we first iterate over the stub code descriptors so

// that the stubs go into the list first. do_blob will then filter out the

// enclosing blobs if the starting address of the enclosing blobs matches the

// starting address of first stub generated in the enclosing blob.

void CodeBlobCollector::collect() {

  assert_locked_or_safepoint(CodeCache_lock);

  assert(_global_code_blobs == NULL, "checking");

  // create the global list

  _global_code_blobs = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JvmtiCodeBlobDesc*>(50,true);

  // iterate over the stub code descriptors and put them in the list first.

  int index = 0;

  StubCodeDesc* desc;

  while ((desc = StubCodeDesc::desc_for_index(++index)) != NULL) {

    _global_code_blobs->append(new JvmtiCodeBlobDesc(desc->name(), desc->begin(), desc->end()));

  }

  // next iterate over all the non-nmethod code blobs and add them to

  // the list - as noted above this will filter out duplicates and

  // enclosing blobs.

  CodeCache::blobs_do(do_blob);

  // make the global list the instance list so that it can be used

  // for other iterations.

  _code_blobs = _global_code_blobs;

  _global_code_blobs = NULL;

}

// Generate a DYNAMIC_CODE_GENERATED event for each non-nmethod code blob.

jvmtiError JvmtiCodeBlobEvents::generate_dynamic_code_events(JvmtiEnv* env) {

  CodeBlobCollector collector;

  // First collect all the code blobs.  This has to be done in a

  // single pass over the code cache with CodeCache_lock held because

  // there isn't any safe way to iterate over regular CodeBlobs since

  // they can be freed at any point.

  {

    MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

    collector.collect();

  }

  // iterate over the collected list and post an event for each blob

  JvmtiCodeBlobDesc* blob = collector.first();

  while (blob != NULL) {

    JvmtiExport::post_dynamic_code_generated(env, blob->name(), blob->code_begin(), blob->code_end());

    blob = collector.next();

  }

  return JVMTI_ERROR_NONE;

}

// Generate a COMPILED_METHOD_LOAD event for each nnmethod

jvmtiError JvmtiCodeBlobEvents::generate_compiled_method_load_events(JvmtiEnv* env) {

  HandleMark hm;

  // Walk the CodeCache notifying for live nmethods.  The code cache

  // may be changing while this is happening which is ok since newly

  // created nmethod will notify normally and nmethods which are freed

  // can be safely skipped.

  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

  nmethod* current = CodeCache::first_nmethod();

  while (current != NULL) {

    // Only notify for live nmethods

    if (current->is_alive()) {

      // Lock the nmethod so it can't be freed

      nmethodLocker nml(current);

      // Don't hold the lock over the notify or jmethodID creation

      MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

      current->get_and_cache_jmethod_id();

      JvmtiExport::post_compiled_method_load(current);

    }

    current = CodeCache::next_nmethod(current);

  }

  return JVMTI_ERROR_NONE;

}

// create a C-heap allocated address location map for an nmethod

void JvmtiCodeBlobEvents::build_jvmti_addr_location_map(nmethod *nm,

                                                        jvmtiAddrLocationMap** map_ptr,

                                                        jint *map_length_ptr)

{

  ResourceMark rm;

  jvmtiAddrLocationMap* map = NULL;

  jint map_length = 0;

  // Generate line numbers using PcDesc and ScopeDesc info

  methodHandle mh(nm->method());

  if (!mh->is_native()) {

    PcDesc *pcd;

    int pcds_in_method;

    pcds_in_method = (nm->scopes_pcs_end() - nm->scopes_pcs_begin());

    map = NEW_C_HEAP_ARRAY(jvmtiAddrLocationMap, pcds_in_method, mtInternal);

    address scopes_data = nm->scopes_data_begin();

    for( pcd = nm->scopes_pcs_begin(); pcd < nm->scopes_pcs_end(); ++pcd ) {

      ScopeDesc sc0(nm, pcd->scope_decode_offset(), pcd->should_reexecute(), pcd->return_oop());

      ScopeDesc *sd  = &sc0;

      while( !sd->is_top() ) { sd = sd->sender(); }

      int bci = sd->bci();

      if (bci != InvocationEntryBci) {

        assert(map_length < pcds_in_method, "checking");

        map[map_length].start_address = (const void*)pcd->real_pc(nm);

        map[map_length].location = bci;

        ++map_length;

      }

    }

  }

  *map_ptr = map;

  *map_length_ptr = map_length;

}