Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1998, 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/debugInfoRec.hpp"

 #include "code/scopeDesc.hpp"

 #include "prims/jvmtiExport.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 {

   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,

                                               bool        reexecute,

                                               bool        is_method_handle_invoke,

                                               bool        return_oop,

                                               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_is_method_handle_invoke(is_method_handle_invoke);

   last_pd->set_return_oop(return_oop);

   // serialize sender stream offest

   stream()->write_int(sender_stream_offset);

   // serialize scope

   Metadata* method_enc = (method == NULL)? NULL: method->constant_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()) ||

          (method->is_compiled_lambda_form() && bci == -99) ||  // this might happen in C1

          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->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() || _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