aoqi@0: /*
aoqi@0:  * Copyright (c) 1998, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_CODE_OOPRECORDER_HPP
aoqi@0: #define SHARE_VM_CODE_OOPRECORDER_HPP
aoqi@0: 
aoqi@0: #include "memory/universe.hpp"
aoqi@0: #include "runtime/handles.hpp"
aoqi@0: #include "utilities/growableArray.hpp"
aoqi@0: 
aoqi@0: // Recording and retrieval of either oop relocations or metadata in compiled code.
aoqi@0: 
aoqi@0: class CodeBlob;
aoqi@0: 
aoqi@0: template <class T> class ValueRecorder : public StackObj {
aoqi@0:  public:
aoqi@0:   // A two-way mapping from positive indexes to oop handles.
aoqi@0:   // The zero index is reserved for a constant (sharable) null.
aoqi@0:   // Indexes may not be negative.
aoqi@0: 
aoqi@0:   // Use the given arena to manage storage, if not NULL.
aoqi@0:   // By default, uses the current ResourceArea.
aoqi@0:   ValueRecorder(Arena* arena = NULL);
aoqi@0: 
aoqi@0:   // Generate a new index on which nmethod::oop_addr_at will work.
aoqi@0:   // allocate_index and find_index never return the same index,
aoqi@0:   // and allocate_index never returns the same index twice.
aoqi@0:   // In fact, two successive calls to allocate_index return successive ints.
aoqi@0:   int allocate_index(T h) {
aoqi@0:     return add_handle(h, false);
aoqi@0:   }
aoqi@0: 
aoqi@0:   // For a given jobject or Metadata*, this will return the same index
aoqi@0:   // repeatedly. The index can later be given to nmethod::oop_at or
aoqi@0:   // metadata_at to retrieve the oop.
aoqi@0:   // However, the oop must not be changed via nmethod::oop_addr_at.
aoqi@0:   int find_index(T h) {
aoqi@0:     int index = maybe_find_index(h);
aoqi@0:     if (index < 0) {  // previously unallocated
aoqi@0:       index = add_handle(h, true);
aoqi@0:     }
aoqi@0:     return index;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // returns the size of the generated oop/metadata table, for sizing the
aoqi@0:   // CodeBlob. Must be called after all oops are allocated!
aoqi@0:   int size();
aoqi@0: 
aoqi@0:   // Retrieve the value at a given index.
aoqi@0:   T at(int index);
aoqi@0: 
aoqi@0:   int count() {
aoqi@0:     if (_handles == NULL) return 0;
aoqi@0:     // there is always a NULL virtually present as first object
aoqi@0:     return _handles->length() + first_index;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Helper function; returns false for NULL or Universe::non_oop_word().
aoqi@0:   bool is_real(T h) {
aoqi@0:     return h != NULL && h != (T)Universe::non_oop_word();
aoqi@0:   }
aoqi@0: 
aoqi@0:   // copy the generated table to nmethod
aoqi@0:   void copy_values_to(nmethod* nm);
aoqi@0: 
aoqi@0:   bool is_unused() { return _handles == NULL && !_complete; }
aoqi@0: #ifdef ASSERT
aoqi@0:   bool is_complete() { return _complete; }
aoqi@0: #endif
aoqi@0: 
aoqi@0:  private:
aoqi@0:   // variant of find_index which does not allocate if not found (yields -1)
aoqi@0:   int maybe_find_index(T h);
aoqi@0: 
aoqi@0:   // leaky hash table of handle => index, to help detect duplicate insertion
aoqi@0:   template <class X> class IndexCache : public ResourceObj {
aoqi@0:     // This class is only used by the ValueRecorder class.
aoqi@0:     friend class ValueRecorder;
aoqi@0:     enum {
aoqi@0:       _log_cache_size = 9,
aoqi@0:       _cache_size = (1<<_log_cache_size),
aoqi@0:       // Index entries are ints.  The LSBit is a collision indicator.
aoqi@0:       _collision_bit_shift = 0,
aoqi@0:       _collision_bit = 1,
aoqi@0:       _index_shift = _collision_bit_shift+1
aoqi@0:     };
aoqi@0:     int _cache[_cache_size];
aoqi@0:     static juint cache_index(X handle) {
aoqi@0:       juint ci = (int) (intptr_t) handle;
aoqi@0:       ci ^= ci >> (BitsPerByte*2);
aoqi@0:       ci += ci >> (BitsPerByte*1);
aoqi@0:       return ci & (_cache_size-1);
aoqi@0:     }
aoqi@0:     int* cache_location(X handle) {
aoqi@0:       return &_cache[ cache_index(handle) ];
aoqi@0:     }
aoqi@0:     static bool cache_location_collision(int* cloc) {
aoqi@0:       return ((*cloc) & _collision_bit) != 0;
aoqi@0:     }
aoqi@0:     static int cache_location_index(int* cloc) {
aoqi@0:       return (*cloc) >> _index_shift;
aoqi@0:     }
aoqi@0:     static void set_cache_location_index(int* cloc, int index) {
aoqi@0:       int cval0 = (*cloc);
aoqi@0:       int cval1 = (index << _index_shift);
aoqi@0:       if (cval0 != 0 && cval1 != cval0)  cval1 += _collision_bit;
aoqi@0:       (*cloc) = cval1;
aoqi@0:     }
aoqi@0:     IndexCache();
aoqi@0:   };
aoqi@0: 
aoqi@0:   void maybe_initialize();
aoqi@0:   int add_handle(T h, bool make_findable);
aoqi@0: 
aoqi@0:   enum { null_index = 0, first_index = 1, index_cache_threshold = 20 };
aoqi@0: 
aoqi@0:   GrowableArray<T>*        _handles;  // ordered list (first is always NULL)
aoqi@0:   GrowableArray<int>*       _no_finds; // all unfindable indexes; usually empty
aoqi@0:   IndexCache<T>*           _indexes;  // map: handle -> its probable index
aoqi@0:   Arena*                    _arena;
aoqi@0:   bool                      _complete;
aoqi@0: 
aoqi@0: #ifdef ASSERT
aoqi@0:   static int _find_index_calls, _hit_indexes, _missed_indexes;
aoqi@0: #endif
aoqi@0: };
aoqi@0: 
aoqi@0: class OopRecorder : public ResourceObj {
aoqi@0:  private:
aoqi@0:   ValueRecorder<jobject>      _oops;
aoqi@0:   ValueRecorder<Metadata*>    _metadata;
aoqi@0:  public:
aoqi@0:   OopRecorder(Arena* arena = NULL): _oops(arena), _metadata(arena) {}
aoqi@0: 
aoqi@0:   int allocate_oop_index(jobject h) {
aoqi@0:     return _oops.allocate_index(h);
aoqi@0:   }
aoqi@0:   int find_index(jobject h) {
aoqi@0:     return _oops.find_index(h);
aoqi@0:   }
aoqi@0:   jobject oop_at(int index) {
aoqi@0:     return _oops.at(index);
aoqi@0:   }
aoqi@0:   int oop_size() {
aoqi@0:     return _oops.size();
aoqi@0:   }
aoqi@0:   int oop_count() {
aoqi@0:     return _oops.count();
aoqi@0:   }
aoqi@0:   bool is_real(jobject h) {
aoqi@0:     return _oops.is_real(h);
aoqi@0:   }
aoqi@0: 
aoqi@0:   int allocate_metadata_index(Metadata* oop) {
aoqi@0:     return _metadata.allocate_index(oop);
aoqi@0:   }
aoqi@0:   int find_index(Metadata* h) {
aoqi@0:     return _metadata.find_index(h);
aoqi@0:   }
aoqi@0:   Metadata* metadata_at(int index) {
aoqi@0:     return _metadata.at(index);
aoqi@0:   }
aoqi@0:   int metadata_size() {
aoqi@0:     return _metadata.size();
aoqi@0:   }
aoqi@0:   int metadata_count() {
aoqi@0:     return _metadata.count();
aoqi@0:   }
aoqi@0:   bool is_real(Metadata* h) {
aoqi@0:     return _metadata.is_real(h);
aoqi@0:   }
aoqi@0: 
aoqi@0:   bool is_unused() {
aoqi@0:     return _oops.is_unused() && _metadata.is_unused();
aoqi@0:   }
aoqi@0: 
aoqi@0:   void freeze() {
aoqi@0:     _oops.size();
aoqi@0:     _metadata.size();
aoqi@0:   }
aoqi@0: 
aoqi@0:   void copy_values_to(nmethod* nm) {
aoqi@0:     if (!_oops.is_unused()) {
aoqi@0:       _oops.copy_values_to(nm);
aoqi@0:     }
aoqi@0:     if (!_metadata.is_unused()) {
aoqi@0:       _metadata.copy_values_to(nm);
aoqi@0:     }
aoqi@0:   }
aoqi@0: 
aoqi@0: #ifdef ASSERT
aoqi@0:   bool is_complete() {
aoqi@0:     assert(_oops.is_complete() == _metadata.is_complete(), "must agree");
aoqi@0:     return _oops.is_complete();
aoqi@0:   }
aoqi@0: #endif
aoqi@0: };
aoqi@0: 
aoqi@0: 
aoqi@0: #endif // SHARE_VM_CODE_OOPRECORDER_HPP