jdk8-mips64-public/hotspot: comparison src/share/vm/interpreter/oopMapCache.hpp

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+/*
+* 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 / file comparison

comparison: src/share/vm/interpreter/oopMapCache.hpp

src/share/vm/interpreter/oopMapCache.hpp