Mercurial > hg > truffle
diff src/share/vm/code/oopRecorder.hpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 1a5913bf5e19 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/code/oopRecorder.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,136 @@ +/* + * Copyright 1998-2005 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. + * + */ + +// Recording and retrieval of oop relocations in compiled code. + +class CodeBlob; + +class OopRecorder : public ResourceObj { + public: + // A two-way mapping from positive indexes to oop handles. + // The zero index is reserved for a constant (sharable) null. + // Indexes may not be negative. + + // Use the given arena to manage storage, if not NULL. + // By default, uses the current ResourceArea. + OopRecorder(Arena* arena = NULL); + + // Generate a new index on which CodeBlob::oop_addr_at will work. + // allocate_index and find_index never return the same index, + // and allocate_index never returns the same index twice. + // In fact, two successive calls to allocate_index return successive ints. + int allocate_index(jobject h) { + return add_handle(h, false); + } + + // For a given jobject, this will return the same index repeatedly. + // The index can later be given to oop_at to retrieve the oop. + // However, the oop must not be changed via CodeBlob::oop_addr_at. + int find_index(jobject h) { + int index = maybe_find_index(h); + if (index < 0) { // previously unallocated + index = add_handle(h, true); + } + return index; + } + + // variant of find_index which does not allocate if not found (yields -1) + int maybe_find_index(jobject h); + + // returns the size of the generated oop table, for sizing the CodeBlob. + // must be called after all oops are allocated! + int oop_size(); + + // Retrieve the oop handle at a given index. + jobject handle_at(int index); + + int element_count() { + // there is always a NULL virtually present as first object + return _handles->length() + first_index; + } + + // copy the generated oop table to CodeBlob + void copy_to(CodeBlob* code); // => code->copy_oops(_handles) + + bool is_unused() { return _handles == NULL && !_complete; } +#ifdef ASSERT + bool is_complete() { return _complete; } +#endif + + private: + // leaky hash table of handle => index, to help detect duplicate insertion + class IndexCache: public ResourceObj { + // This class is only used by the OopRecorder class. + friend class OopRecorder; + enum { + _log_cache_size = 9, + _cache_size = (1<<_log_cache_size), + // Index entries are ints. The LSBit is a collision indicator. + _collision_bit_shift = 0, + _collision_bit = 1, + _index_shift = _collision_bit_shift+1 + }; + int _cache[_cache_size]; + static juint cache_index(jobject handle) { + juint ci = (int) (intptr_t) handle; + ci ^= ci >> (BitsPerByte*2); + ci += ci >> (BitsPerByte*1); + return ci & (_cache_size-1); + } + int* cache_location(jobject handle) { + return &_cache[ cache_index(handle) ]; + } + static bool cache_location_collision(int* cloc) { + return ((*cloc) & _collision_bit) != 0; + } + static int cache_location_index(int* cloc) { + return (*cloc) >> _index_shift; + } + static void set_cache_location_index(int* cloc, int index) { + int cval0 = (*cloc); + int cval1 = (index << _index_shift); + if (cval0 != 0 && cval1 != cval0) cval1 += _collision_bit; + (*cloc) = cval1; + } + IndexCache(); + }; + + // Helper function; returns false for NULL or Universe::non_oop_word(). + inline bool is_real_jobject(jobject h); + + void maybe_initialize(); + int add_handle(jobject h, bool make_findable); + + enum { null_index = 0, first_index = 1, index_cache_threshold = 20 }; + + GrowableArray<jobject>* _handles; // ordered list (first is always NULL) + GrowableArray<int>* _no_finds; // all unfindable indexes; usually empty + IndexCache* _indexes; // map: jobject -> its probable index + Arena* _arena; + bool _complete; + +#ifdef ASSERT + static int _find_index_calls, _hit_indexes, _missed_indexes; +#endif +};