Ziele Untersuchung
mit Columbo Integrität von
Datenbanken Interaktion und
Portierbarkeit Ergonomie der
Schnittstellen

Angebot Produkte Projekt Beratung

Mittel Analytik Modellierung Sprachen Algebra Logik Hardware Denken Kreativität

Zusammenhänge Gesellschaft Wirtschaft Branche Firma


products/sources/formale Sprachen/Java/Openjdk/src/hotspot/share/code/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 15 kB

Quelle debugInfoRec.cpp Sprache: C

/*
* Copyright (c) 1998, 2022, 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/debugInfoRec.hpp"
#include "code/scopeDesc.hpp"
#include "compiler/oopMap.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/globals_extension.hpp"

// Private definition.
// There is one DIR_Chunk for each scope and values array.
// A chunk can potentially be used more than once.
// We keep track of these chunks in order to detect
// repetition and enable sharing.
class DIR_Chunk {
private:
  int  _offset; // location in the stream of this scope
  int  _length; // number of bytes in the stream
  int  _hash;   // hash of stream bytes (for quicker reuse)
  DebugInformationRecorder* _DIR;

public:
  int offset() { return _offset; }

  void* operator new(size_t ignore, DebugInformationRecorder* dir) throw() {
    assert(ignore == sizeof(DIR_Chunk), "");
    if (dir->_next_chunk >= dir->_next_chunk_limit) {
      const int CHUNK = 100;
      dir->_next_chunk = NEW_RESOURCE_ARRAY(DIR_Chunk, CHUNK);
      dir->_next_chunk_limit = dir->_next_chunk + CHUNK;
    }
    return dir->_next_chunk++;
  }

  DIR_Chunk(int offset, int length, DebugInformationRecorder* dir) {
    _offset = offset;
    _length = length;
    _DIR = dir;
    unsigned int hash = 0;
    address p = dir->stream()->buffer() + _offset;
    for (int i = 0; i < length; i++) {
      if (i == 6)  break;
      hash *= 127;
      hash += p[i];
    }
    _hash = hash;
  }

  DIR_Chunk* find_match(GrowableArray<DIR_Chunk*>* arr,
                        int start_index,
                        DebugInformationRecorder* dir) {
    int end_index = arr->length();
    int hash = this->_hash, length = this->_length;
    address buf = dir->stream()->buffer();
    for (int i = end_index; --i >= start_index; ) {
      DIR_Chunk* that = arr->at(i);
      if (hash   == that->_hash &&
          length == that->_length &&
          0 == memcmp(buf + this->_offset, buf + that->_offset, length)) {
        return that;
      }
    }
    return NULL;
  }

  static int compare(DIR_Chunk* const & a, DIR_Chunk* const & b) {
    if (b->_hash > a->_hash) {
      return 1;
    }
    if (b->_hash < a->_hash) {
      return -1;
    }
    if (b->_length > a->_length) {
      return 1;
    }
    if (b->_length < a->_length) {
      return -1;
    }
    address buf = a->_DIR->stream()->buffer();
    return memcmp(buf + b->_offset, buf + a->_offset, a->_length);
  }
};

static inline bool compute_recording_non_safepoints() {
  if (JvmtiExport::should_post_compiled_method_load()
      && FLAG_IS_DEFAULT(DebugNonSafepoints)) {
    // The default value of this flag is taken to be true,
    // if JVMTI is looking at nmethod codes.
    // We anticipate that JVMTI may wish to participate in profiling.
    return true;
  }

  // If the flag is set manually, use it, whether true or false.
  // Otherwise, if JVMTI is not in the picture, use the default setting.
  // (This is true in debug, just for the exercise, false in product mode.)
  return DebugNonSafepoints;
}

DebugInformationRecorder::DebugInformationRecorder(OopRecorder* oop_recorder)
  : _recording_non_safepoints(compute_recording_non_safepoints())
{
  _pcs_size   = 100;
  _pcs        = NEW_RESOURCE_ARRAY(PcDesc, _pcs_size);
  _pcs_length = 0;

  _prev_safepoint_pc = PcDesc::lower_offset_limit;

  _stream = new DebugInfoWriteStream(this, 10 * K);
  // make sure that there is no stream_decode_offset that is zero
  _stream->write_byte((jbyte)0xFF);

  // make sure that we can distinguish the value "serialized_null" from offsets
  assert(_stream->position() > serialized_null, "sanity");

  _oop_recorder = oop_recorder;

  _all_chunks    = new GrowableArray<DIR_Chunk*>(300);
  _next_chunk = _next_chunk_limit = NULL;

  add_new_pc_offset(PcDesc::lower_offset_limit);  // sentinel record

  debug_only(_recording_state = rs_null);
}

void DebugInformationRecorder::add_oopmap(int pc_offset, OopMap* map) {
  // !!!!! Preserve old style handling of oopmaps for now
  _oopmaps->add_gc_map(pc_offset, map);
}

void DebugInformationRecorder::add_safepoint(int pc_offset, OopMap* map) {
  assert(!_oop_recorder->is_complete(), "not frozen yet");
  // Store the new safepoint

  // Add the oop map
  add_oopmap(pc_offset, map);

  add_new_pc_offset(pc_offset);

  assert(_recording_state == rs_null, "nesting of recording calls");
  debug_only(_recording_state = rs_safepoint);
}

void DebugInformationRecorder::add_non_safepoint(int pc_offset) {
  assert(!_oop_recorder->is_complete(), "not frozen yet");
  assert(_recording_non_safepoints, "must be recording non-safepoints");

  add_new_pc_offset(pc_offset);

  assert(_recording_state == rs_null, "nesting of recording calls");
  debug_only(_recording_state = rs_non_safepoint);
}

void DebugInformationRecorder::add_new_pc_offset(int pc_offset) {
  assert(_pcs_length == 0 || last_pc()->pc_offset() < pc_offset,
         "must specify a new, larger pc offset");

  // add the pcdesc
  if (_pcs_length == _pcs_size) {
    // Expand
    int     new_pcs_size = _pcs_size * 2;
    PcDesc* new_pcs      = NEW_RESOURCE_ARRAY(PcDesc, new_pcs_size);
    for (int index = 0; index < _pcs_length; index++) {
      new_pcs[index] = _pcs[index];
    }
    _pcs_size = new_pcs_size;
    _pcs      = new_pcs;
  }
  assert(_pcs_size > _pcs_length, "There must be room for after expanding");

  _pcs[_pcs_length++] = PcDesc(pc_offset, DebugInformationRecorder::serialized_null,
                               DebugInformationRecorder::serialized_null);
}

int DebugInformationRecorder::serialize_monitor_values(GrowableArray<MonitorValue*>* monitors) {
  if (monitors == NULL || monitors->is_empty()) return DebugInformationRecorder::serialized_null;
  assert(_recording_state == rs_safepoint, "must be recording a safepoint");
  int result = stream()->position();
  stream()->write_int(monitors->length());
  for (int index = 0; index < monitors->length(); index++) {
    monitors->at(index)->write_on(stream());
  }
  assert(result != serialized_null, "sanity");

  // (See comment below on DebugInformationRecorder::describe_scope.)
  int shared_result = find_sharable_decode_offset(result);
  if (shared_result != serialized_null) {
    stream()->set_position(result);
    result = shared_result;
  }

  return result;
}

int DebugInformationRecorder::serialize_scope_values(GrowableArray<ScopeValue*>* values) {
  if (values == NULL || values->is_empty()) return DebugInformationRecorder::serialized_null;
  assert(_recording_state == rs_safepoint, "must be recording a safepoint");
  int result = stream()->position();
  assert(result != serialized_null, "sanity");
  stream()->write_int(values->length());
  for (int index = 0; index < values->length(); index++) {
    values->at(index)->write_on(stream());
  }

  // (See comment below on DebugInformationRecorder::describe_scope.)
  int shared_result = find_sharable_decode_offset(result);
  if (shared_result != serialized_null) {
    stream()->set_position(result);
    result = shared_result;
  }

  return result;
}

#ifndef PRODUCT
// These variables are put into one block to reduce relocations
// and make it simpler to print from the debugger.
static
struct dir_stats_struct {
  int chunks_queried;
  int chunks_shared;
  int chunks_reshared;
  int chunks_elided;

  void print() {
    tty->print_cr("Debug Data Chunks: %d, shared %d+%d, non-SP's elided %d",
                  chunks_queried,
                  chunks_shared, chunks_reshared,
                  chunks_elided);
  }
} dir_stats;
#endif //PRODUCT

int DebugInformationRecorder::find_sharable_decode_offset(int stream_offset) {
  NOT_PRODUCT(++dir_stats.chunks_queried);
  int stream_length = stream()->position() - stream_offset;
  assert(stream_offset != serialized_null, "should not be null");
  assert(stream_length != 0, "should not be empty");

  DIR_Chunk* ns = new(this) DIR_Chunk(stream_offset, stream_length, this);

  DIR_Chunk* match = _all_chunks->insert_sorted<DIR_Chunk::compare>(ns);
  if (match != ns) {
    // Found an existing chunk
    NOT_PRODUCT(++dir_stats.chunks_shared);
    assert(ns+1 == _next_chunk, "");
    _next_chunk = ns;
    return match->offset();
  } else {
    // Inserted this chunk, so nothing to do
    return serialized_null;
  }
}

// must call add_safepoint before: it sets PcDesc and this routine uses
// the last PcDesc set
void DebugInformationRecorder::describe_scope(int         pc_offset,
                                              const methodHandle& methodH,
                                              ciMethod*   method,
                                              int         bci,
                                              bool        reexecute,
                                              bool        rethrow_exception,
                                              bool        is_method_handle_invoke,
                                              bool        return_oop,
                                              bool        has_ea_local_in_scope,
                                              bool        arg_escape,
                                              DebugToken* locals,
                                              DebugToken* expressions,
                                              DebugToken* monitors) {
  assert(_recording_state != rs_null, "nesting of recording calls");
  PcDesc* last_pd = last_pc();
  assert(last_pd->pc_offset() == pc_offset, "must be last pc");
  int sender_stream_offset = last_pd->scope_decode_offset();
  // update the stream offset of current pc desc
  int stream_offset = stream()->position();
  last_pd->set_scope_decode_offset(stream_offset);

  // Record flags into pcDesc.
  last_pd->set_should_reexecute(reexecute);
  last_pd->set_rethrow_exception(rethrow_exception);
  last_pd->set_is_method_handle_invoke(is_method_handle_invoke);
  last_pd->set_return_oop(return_oop);
  last_pd->set_has_ea_local_in_scope(has_ea_local_in_scope);
  last_pd->set_arg_escape(arg_escape);

  // serialize sender stream offset
  stream()->write_int(sender_stream_offset);

  // serialize scope
  Metadata* method_enc;
  if (method != NULL) {
    method_enc = method->constant_encoding();
  } else if (methodH.not_null()) {
    method_enc = methodH();
  } else {
    method_enc = NULL;
  }
  int method_enc_index = oop_recorder()->find_index(method_enc);
  stream()->write_int(method_enc_index);
  stream()->write_bci(bci);
  assert(method == NULL ||
         (method->is_native() && bci == 0) ||
         (!method->is_native() && 0 <= bci && bci < method->code_size()) ||
         bci == -1, "illegal bci");

  // serialize the locals/expressions/monitors
  stream()->write_int((intptr_t) locals);
  stream()->write_int((intptr_t) expressions);
  stream()->write_int((intptr_t) monitors);

  // Here's a tricky bit.  We just wrote some bytes.
  // Wouldn't it be nice to find that we had already
  // written those same bytes somewhere else?
  // If we get lucky this way, reset the stream
  // and reuse the old bytes.  By the way, this
  // trick not only shares parent scopes, but also
  // compresses equivalent non-safepoint PcDescs.
  int shared_stream_offset = find_sharable_decode_offset(stream_offset);
  if (shared_stream_offset != serialized_null) {
    stream()->set_position(stream_offset);
    last_pd->set_scope_decode_offset(shared_stream_offset);
  }
}

void DebugInformationRecorder::dump_object_pool(GrowableArray<ScopeValue*>* objects) {
  guarantee( _pcs_length > 0, "safepoint must exist before describing scopes");
  PcDesc* last_pd = &_pcs[_pcs_length-1];
  if (objects != NULL) {
    for (int i = objects->length() - 1; i >= 0; i--) {
      objects->at(i)->as_ObjectValue()->set_visited(false);
    }
  }
  int offset = serialize_scope_values(objects);
  last_pd->set_obj_decode_offset(offset);
}

void DebugInformationRecorder::end_scopes(int pc_offset, bool is_safepoint) {
  assert(_recording_state == (is_safepoint? rs_safepoint: rs_non_safepoint),
         "nesting of recording calls");
  debug_only(_recording_state = rs_null);

  // Try to compress away an equivalent non-safepoint predecessor.
  // (This only works because we have previously recognized redundant
  // scope trees and made them use a common scope_decode_offset.)
  if (_pcs_length >= 2 && recording_non_safepoints()) {
    PcDesc* last = last_pc();
    PcDesc* prev = prev_pc();
    // If prev is (a) not a safepoint and (b) has the same
    // stream pointer, then it can be coalesced into the last.
    // This is valid because non-safepoints are only sought
    // with pc_desc_near, which (when it misses prev) will
    // search forward until it finds last.
    // In addition, it does not matter if the last PcDesc
    // is for a safepoint or not.
    if (_prev_safepoint_pc < prev->pc_offset() && prev->is_same_info(last)) {
      assert(prev == last-1, "sane");
      prev->set_pc_offset(pc_offset);
      _pcs_length -= 1;
      NOT_PRODUCT(++dir_stats.chunks_elided);
    }
  }

  // We have just recorded this safepoint.
  // Remember it in case the previous paragraph needs to know.
  if (is_safepoint) {
    _prev_safepoint_pc = pc_offset;
  }
}

#ifdef ASSERT
bool DebugInformationRecorder::recorders_frozen() {
  return _oop_recorder->is_complete();
}

void DebugInformationRecorder::mark_recorders_frozen() {
  _oop_recorder->freeze();
}
#endif // PRODUCT

DebugToken* DebugInformationRecorder::create_scope_values(GrowableArray<ScopeValue*>* values) {
  assert(!recorders_frozen(), "not frozen yet");
  return (DebugToken*) (intptr_t) serialize_scope_values(values);
}

DebugToken* DebugInformationRecorder::create_monitor_values(GrowableArray<MonitorValue*>* monitors) {
  assert(!recorders_frozen(), "not frozen yet");
  return (DebugToken*) (intptr_t) serialize_monitor_values(monitors);
}

int DebugInformationRecorder::data_size() {
  debug_only(mark_recorders_frozen());  // mark it "frozen" for asserts
  return _stream->position();
}

int DebugInformationRecorder::pcs_size() {
  debug_only(mark_recorders_frozen());  // mark it "frozen" for asserts
  if (last_pc()->pc_offset() != PcDesc::upper_offset_limit)
    add_new_pc_offset(PcDesc::upper_offset_limit);
  return _pcs_length * sizeof(PcDesc);
}

void DebugInformationRecorder::copy_to(nmethod* nm) {
  nm->copy_scopes_data(stream()->buffer(), stream()->position());
  nm->copy_scopes_pcs(_pcs, _pcs_length);
}

void DebugInformationRecorder::verify(const nmethod* code) {
  Unimplemented();
}

#ifndef PRODUCT
void DebugInformationRecorder::print_statistics() {
  dir_stats.print();
}
#endif //PRODUCT

quality92%

¤ Dauer der Verarbeitung: 0.13 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.