--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/code/debugInfoRec.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,411 @@
+/*
+ * Copyright 1998-2006 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.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_debugInfoRec.cpp.incl"
+
+// 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 {
+  friend class DebugInformationRecorder;
+  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)
+
+  void* operator new(size_t ignore, DebugInformationRecorder* dir) {
+    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;
+    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 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);
+  _shared_chunks = new GrowableArray<DIR_Chunk*>(30);
+  _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) {
+  // Only pull this trick if non-safepoint recording
+  // is enabled, for now.
+  if (!recording_non_safepoints())
+    return serialized_null;
+
+  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);
+
+  // Look in previously shared scopes first:
+  DIR_Chunk* ms = ns->find_match(_shared_chunks, 0, this);
+  if (ms != NULL) {
+    NOT_PRODUCT(++dir_stats.chunks_reshared);
+    assert(ns+1 == _next_chunk, "");
+    _next_chunk = ns;
+    return ms->_offset;
+  }
+
+  // Look in recently encountered scopes next:
+  const int MAX_RECENT = 50;
+  int start_index = _all_chunks->length() - MAX_RECENT;
+  if (start_index < 0)  start_index = 0;
+  ms = ns->find_match(_all_chunks, start_index, this);
+  if (ms != NULL) {
+    NOT_PRODUCT(++dir_stats.chunks_shared);
+    // Searching in _all_chunks is limited to a window,
+    // but searching in _shared_chunks is unlimited.
+    _shared_chunks->append(ms);
+    assert(ns+1 == _next_chunk, "");
+    _next_chunk = ns;
+    return ms->_offset;
+  }
+
+  // No match.  Add this guy to the list, in hopes of future shares.
+  _all_chunks->append(ns);
+  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,
+                                              ciMethod*   method,
+                                              int         bci,
+                                              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);
+
+  // serialize sender stream offest
+  stream()->write_int(sender_stream_offset);
+
+  // serialize scope
+  jobject method_enc = (method == NULL)? NULL: method->encoding();
+  stream()->write_int(oop_recorder()->find_index(method_enc));
+  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--) {
+      ((ObjectValue*) objects->at(i))->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->scope_decode_offset() == last->scope_decode_offset()) {
+      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;
+  }
+}
+
+DebugToken* DebugInformationRecorder::create_scope_values(GrowableArray<ScopeValue*>* values) {
+  assert(!_oop_recorder->is_complete(), "not frozen yet");
+  return (DebugToken*) (intptr_t) serialize_scope_values(values);
+}
+
+
+DebugToken* DebugInformationRecorder::create_monitor_values(GrowableArray<MonitorValue*>* monitors) {
+  assert(!_oop_recorder->is_complete(), "not frozen yet");
+  return (DebugToken*) (intptr_t) serialize_monitor_values(monitors);
+}
+
+
+int DebugInformationRecorder::data_size() {
+  debug_only(_oop_recorder->oop_size());  // mark it "frozen" for asserts
+  return _stream->position();
+}
+
+
+int DebugInformationRecorder::pcs_size() {
+  debug_only(_oop_recorder->oop_size());  // 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