jdk8-mips64-public/hotspot: src/share/vm/interpreter/oopMapCache.hpp@f90c822e73f8 (annotated)

src/share/vm/interpreter/oopMapCache.hpp@f90c822e73f8 (annotated)

src/share/vm/interpreter/oopMapCache.hpp

Wed, 27 Apr 2016 01:25:04 +0800

author: aoqi
date: Wed, 27 Apr 2016 01:25:04 +0800
changeset 0: f90c822e73f8
child 6876: 710a3c8b516e
permissions: -rw-r--r--

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http://hg.openjdk.java.net/jdk8u/jdk8u/hotspot/
changeset: 6782:28b50d07f6f8
tag: jdk8u25-b17

 /*
  * Copyright (c) 1997, 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.
  *
  */
 #ifndef SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP
 #define SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP
 #include "oops/generateOopMap.hpp"
 #include "runtime/mutex.hpp"
 // A Cache for storing (method, bci) -> oopMap.
 // The memory management system uses the cache when locating object
 // references in an interpreted frame.
 //
 // OopMapCache's are allocated lazily per InstanceKlass.
 // The oopMap (InterpreterOopMap) is stored as a bit mask. If the
 // bit_mask can fit into two words it is stored in
 // the _bit_mask array, otherwise it is allocated on the heap.
 // For OopMapCacheEntry the bit_mask is allocated in the C heap
 // because these entries persist between garbage collections.
 // For InterpreterOopMap the bit_mask is allocated in
 // a resource area for better performance.  InterpreterOopMap
 // should only be created and deleted during same garbage collection.
 //
 // If ENABBLE_ZAP_DEAD_LOCALS is defined, two bits are used
 // per entry instead of one. In all cases,
 // the first bit is set to indicate oops as opposed to other
 // values. If the second bit is available,
 // it is set for dead values. We get the following encoding:
 //
 // 00 live value
 // 01 live oop
 // 10 dead value
 // 11 <unused>                                   (we cannot distinguish between dead oops or values with the current oop map generator)
 class OffsetClosure  {
  public:
   virtual void offset_do(int offset) = 0;
 };
 class InterpreterOopMap: ResourceObj {
   friend class OopMapCache;
  public:
   enum {
     N                = 2,                // the number of words reserved
                                          // for inlined mask storage
     small_mask_limit = N * BitsPerWord,  // the maximum number of bits
                                          // available for small masks,
                                          // small_mask_limit can be set to 0
                                          // for testing bit_mask allocation
 #ifdef ENABLE_ZAP_DEAD_LOCALS
     bits_per_entry   = 2,
     dead_bit_number  = 1,
 #else
     bits_per_entry   = 1,
 #endif
     oop_bit_number   = 0
   };
  private:
   Method*        _method;         // the method for which the mask is valid
   unsigned short _bci;            // the bci    for which the mask is valid
   int            _mask_size;      // the mask size in bits
   int            _expression_stack_size; // the size of the expression stack in slots
  protected:
   intptr_t       _bit_mask[N];    // the bit mask if
                                   // mask_size <= small_mask_limit,
                                   // ptr to bit mask otherwise
                                   // "protected" so that sub classes can
                                   // access it without using trickery in
                                   // methd bit_mask().
 #ifdef ASSERT
   bool _resource_allocate_bit_mask;
 #endif
   // access methods
   Method*        method() const                  { return _method; }
   void           set_method(Method* v)         { _method = v; }
   int            bci() const                     { return _bci; }
   void           set_bci(int v)                  { _bci = v; }
   int            mask_size() const               { return _mask_size; }
   void           set_mask_size(int v)            { _mask_size = v; }
   int            number_of_entries() const       { return mask_size() / bits_per_entry; }
   // Test bit mask size and return either the in-line bit mask or allocated
   // bit mask.
   uintptr_t*  bit_mask()                         { return (uintptr_t*)(mask_size() <= small_mask_limit ? (intptr_t)_bit_mask : _bit_mask[0]); }
   // return the word size of_bit_mask.  mask_size() <= 4 * MAX_USHORT
   size_t mask_word_size() {
     return (mask_size() + BitsPerWord - 1) / BitsPerWord;
   }
   uintptr_t entry_at(int offset)            { int i = offset * bits_per_entry; return bit_mask()[i / BitsPerWord] >> (i % BitsPerWord); }
   void set_expression_stack_size(int sz)    { _expression_stack_size = sz; }
 #ifdef ENABLE_ZAP_DEAD_LOCALS
   bool is_dead(int offset)                       { return (entry_at(offset) & (1 << dead_bit_number)) != 0; }
 #endif
   // Lookup
   bool match(methodHandle method, int bci)       { return _method == method() && _bci == bci; }
   bool is_empty();
   // Initialization
   void initialize();
  public:
   InterpreterOopMap();
   ~InterpreterOopMap();
   // Copy the OopMapCacheEntry in parameter "from" into this
   // InterpreterOopMap.  If the _bit_mask[0] in "from" points to
   // allocated space (i.e., the bit mask was to large to hold
   // in-line), allocate the space from a Resource area.
   void resource_copy(OopMapCacheEntry* from);
   void iterate_oop(OffsetClosure* oop_closure);
   void print();
   bool is_oop  (int offset)                      { return (entry_at(offset) & (1 << oop_bit_number )) != 0; }
   int expression_stack_size()                    { return _expression_stack_size; }
 #ifdef ENABLE_ZAP_DEAD_LOCALS
   void iterate_all(OffsetClosure* oop_closure, OffsetClosure* value_closure, OffsetClosure* dead_closure);
 #endif
 };
 class OopMapCache : public CHeapObj<mtClass> {
  private:
   enum { _size        = 32,     // Use fixed size for now
          _probe_depth = 3       // probe depth in case of collisions
   };
   OopMapCacheEntry* _array;
   unsigned int hash_value_for(methodHandle method, int bci);
   OopMapCacheEntry* entry_at(int i) const;
   Mutex _mut;
   void flush();
  public:
   OopMapCache();
   ~OopMapCache();                                // free up memory
   // flush cache entry is occupied by an obsolete method
   void flush_obsolete_entries();
   // Returns the oopMap for (method, bci) in parameter "entry".
   // Returns false if an oop map was not found.
   void lookup(methodHandle method, int bci, InterpreterOopMap* entry);
   // Compute an oop map without updating the cache or grabbing any locks (for debugging)
   static void compute_one_oop_map(methodHandle method, int bci, InterpreterOopMap* entry);
   // Returns total no. of bytes allocated as part of OopMapCache's
   static long memory_usage()                     PRODUCT_RETURN0;
 };
 #endif // SHARE_VM_INTERPRETER_OOPMAPCACHE_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/interpreter/oopMapCache.hpp@f90c822e73f8 (annotated)

src/share/vm/interpreter/oopMapCache.hpp