diff -r 0b27f3512f9e -r 37f87013dfd8 src/share/vm/utilities/bitMap.hpp --- a/src/share/vm/utilities/bitMap.hpp Wed Jun 04 13:51:09 2008 -0700 +++ b/src/share/vm/utilities/bitMap.hpp Thu Jun 05 15:57:56 2008 -0700 @@ -22,25 +22,19 @@ * */ -// Closure for iterating over BitMaps +// Forward decl; +class BitMapClosure; -class BitMapClosure VALUE_OBJ_CLASS_SPEC { - public: - // Callback when bit in map is set - virtual void do_bit(size_t offset) = 0; -}; - - -// Operations for bitmaps represented as arrays of unsigned 32- or 64-bit -// integers (uintptr_t). -// -// Bit offsets are numbered from 0 to size-1 +// Operations for bitmaps represented as arrays of unsigned integers. +// Bit offsets are numbered from 0 to size-1. class BitMap VALUE_OBJ_CLASS_SPEC { friend class BitMap2D; public: typedef size_t idx_t; // Type used for bit and word indices. + typedef uintptr_t bm_word_t; // Element type of array that represents + // the bitmap. // Hints for range sizes. typedef enum { @@ -48,8 +42,8 @@ } RangeSizeHint; private: - idx_t* _map; // First word in bitmap - idx_t _size; // Size of bitmap (in bits) + bm_word_t* _map; // First word in bitmap + idx_t _size; // Size of bitmap (in bits) // Puts the given value at the given offset, using resize() to size // the bitmap appropriately if needed using factor-of-two expansion. @@ -62,7 +56,7 @@ // Return a mask that will select the specified bit, when applied to the word // containing the bit. - static idx_t bit_mask(idx_t bit) { return (idx_t)1 << bit_in_word(bit); } + static bm_word_t bit_mask(idx_t bit) { return (bm_word_t)1 << bit_in_word(bit); } // Return the index of the word containing the specified bit. static idx_t word_index(idx_t bit) { return bit >> LogBitsPerWord; } @@ -71,66 +65,68 @@ static idx_t bit_index(idx_t word) { return word << LogBitsPerWord; } // Return the array of bitmap words, or a specific word from it. - idx_t* map() const { return _map; } - idx_t map(idx_t word) const { return _map[word]; } + bm_word_t* map() const { return _map; } + bm_word_t map(idx_t word) const { return _map[word]; } // Return a pointer to the word containing the specified bit. - idx_t* word_addr(idx_t bit) const { return map() + word_index(bit); } + bm_word_t* word_addr(idx_t bit) const { return map() + word_index(bit); } // Set a word to a specified value or to all ones; clear a word. - void set_word (idx_t word, idx_t val) { _map[word] = val; } + void set_word (idx_t word, bm_word_t val) { _map[word] = val; } void set_word (idx_t word) { set_word(word, ~(uintptr_t)0); } void clear_word(idx_t word) { _map[word] = 0; } // Utilities for ranges of bits. Ranges are half-open [beg, end). // Ranges within a single word. - inline idx_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; - inline void set_range_within_word (idx_t beg, idx_t end); - inline void clear_range_within_word (idx_t beg, idx_t end); - inline void par_put_range_within_word (idx_t beg, idx_t end, bool value); + bm_word_t inverted_bit_mask_for_range(idx_t beg, idx_t end) const; + void set_range_within_word (idx_t beg, idx_t end); + void clear_range_within_word (idx_t beg, idx_t end); + void par_put_range_within_word (idx_t beg, idx_t end, bool value); // Ranges spanning entire words. - inline void set_range_of_words (idx_t beg, idx_t end); - inline void clear_range_of_words (idx_t beg, idx_t end); - inline void set_large_range_of_words (idx_t beg, idx_t end); - inline void clear_large_range_of_words (idx_t beg, idx_t end); + void set_range_of_words (idx_t beg, idx_t end); + void clear_range_of_words (idx_t beg, idx_t end); + void set_large_range_of_words (idx_t beg, idx_t end); + void clear_large_range_of_words (idx_t beg, idx_t end); // The index of the first full word in a range. - inline idx_t word_index_round_up(idx_t bit) const; + idx_t word_index_round_up(idx_t bit) const; // Verification, statistics. - void verify_index(idx_t index) const { - assert(index < _size, "BitMap index out of bounds"); - } + void verify_index(idx_t index) const; + void verify_range(idx_t beg_index, idx_t end_index) const; - void verify_range(idx_t beg_index, idx_t end_index) const { -#ifdef ASSERT - assert(beg_index <= end_index, "BitMap range error"); - // Note that [0,0) and [size,size) are both valid ranges. - if (end_index != _size) verify_index(end_index); -#endif - } + static idx_t* _pop_count_table; + static void init_pop_count_table(); + static idx_t num_set_bits(bm_word_t w); + static idx_t num_set_bits_from_table(unsigned char c); public: // Constructs a bitmap with no map, and size 0. BitMap() : _map(NULL), _size(0) {} - // Construction - BitMap(idx_t* map, idx_t size_in_bits); + // Constructs a bitmap with the given map and size. + BitMap(bm_word_t* map, idx_t size_in_bits); - // Allocates necessary data structure in resource area - BitMap(idx_t size_in_bits); + // Constructs an empty bitmap of the given size (that is, this clears the + // new bitmap). Allocates the map array in resource area if + // "in_resource_area" is true, else in the C heap. + BitMap(idx_t size_in_bits, bool in_resource_area = true); - void set_map(idx_t* map) { _map = map; } + // Set the map and size. + void set_map(bm_word_t* map) { _map = map; } void set_size(idx_t size_in_bits) { _size = size_in_bits; } - // Allocates necessary data structure in resource area. + // Allocates necessary data structure, either in the resource area + // or in the C heap, as indicated by "in_resource_area." // Preserves state currently in bit map by copying data. // Zeros any newly-addressable bits. - // Does not perform any frees (i.e., of current _map). - void resize(idx_t size_in_bits); + // If "in_resource_area" is false, frees the current map. + // (Note that this assumes that all calls to "resize" on the same BitMap + // use the same value for "in_resource_area".) + void resize(idx_t size_in_bits, bool in_resource_area = true); // Accessing idx_t size() const { return _size; } @@ -157,11 +153,11 @@ // Set or clear the specified bit. inline void set_bit(idx_t bit); - inline void clear_bit(idx_t bit); + void clear_bit(idx_t bit); // Atomically set or clear the specified bit. - inline bool par_set_bit(idx_t bit); - inline bool par_clear_bit(idx_t bit); + bool par_set_bit(idx_t bit); + bool par_clear_bit(idx_t bit); // Put the given value at the given offset. The parallel version // will CAS the value into the bitmap and is quite a bit slower. @@ -183,23 +179,61 @@ // Update a range of bits, using a hint about the size. Currently only // inlines the predominant case of a 1-bit range. Works best when hint is a // compile-time constant. - inline void set_range(idx_t beg, idx_t end, RangeSizeHint hint); - inline void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); - inline void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); - inline void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); + void set_range(idx_t beg, idx_t end, RangeSizeHint hint); + void clear_range(idx_t beg, idx_t end, RangeSizeHint hint); + void par_set_range(idx_t beg, idx_t end, RangeSizeHint hint); + void par_clear_range (idx_t beg, idx_t end, RangeSizeHint hint); + + // It performs the union operation between subsets of equal length + // of two bitmaps (the target bitmap of the method and the + // from_bitmap) and stores the result to the target bitmap. The + // from_start_index represents the first bit index of the subrange + // of the from_bitmap. The to_start_index is the equivalent of the + // target bitmap. Both indexes should be word-aligned, i.e. they + // should correspond to the first bit on a bitmap word (it's up to + // the caller to ensure this; the method does check it). The length + // of the subset is specified with word_num and it is in number of + // bitmap words. The caller should ensure that this is at least 2 + // (smaller ranges are not support to save extra checks). Again, + // this is checked in the method. + // + // Atomicity concerns: it is assumed that any contention on the + // target bitmap with other threads will happen on the first and + // last words; the ones in between will be "owned" exclusively by + // the calling thread and, in fact, they will already be 0. So, the + // method performs a CAS on the first word, copies the next + // word_num-2 words, and finally performs a CAS on the last word. + void mostly_disjoint_range_union(BitMap* from_bitmap, + idx_t from_start_index, + idx_t to_start_index, + size_t word_num); + // Clearing - void clear(); void clear_large(); + inline void clear(); - // Iteration support - void iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); - inline void iterate(BitMapClosure* blk) { + // Iteration support. Returns "true" if the iteration completed, false + // if the iteration terminated early (because the closure "blk" returned + // false). + bool iterate(BitMapClosure* blk, idx_t leftIndex, idx_t rightIndex); + bool iterate(BitMapClosure* blk) { // call the version that takes an interval - iterate(blk, 0, size()); + return iterate(blk, 0, size()); } - // Looking for 1's and 0's to the "right" + // Looking for 1's and 0's at indices equal to or greater than "l_index", + // stopping if none has been found before "r_index", and returning + // "r_index" (which must be at most "size") in that case. + idx_t get_next_one_offset_inline (idx_t l_index, idx_t r_index) const; + idx_t get_next_zero_offset_inline(idx_t l_index, idx_t r_index) const; + + // Like "get_next_one_offset_inline", except requires that "r_index" is + // aligned to bitsizeof(bm_word_t). + idx_t get_next_one_offset_inline_aligned_right(idx_t l_index, + idx_t r_index) const; + + // Non-inline versionsof the above. idx_t get_next_one_offset (idx_t l_index, idx_t r_index) const; idx_t get_next_zero_offset(idx_t l_index, idx_t r_index) const; @@ -210,12 +244,8 @@ return get_next_zero_offset(offset, size()); } - - - // Find the next one bit in the range [beg_bit, end_bit), or return end_bit if - // no one bit is found. Equivalent to get_next_one_offset(), but inline for - // use in performance-critical code. - inline idx_t find_next_one_bit(idx_t beg_bit, idx_t end_bit) const; + // Returns the number of bits set in the bitmap. + idx_t count_one_bits() const; // Set operations. void set_union(BitMap bits); @@ -232,6 +262,15 @@ bool set_difference_with_result(BitMap bits); bool set_intersection_with_result(BitMap bits); + // Requires the submap of "bits" starting at offset to be at least as + // large as "this". Modifies "this" to be the intersection of its + // current contents and the submap of "bits" starting at "offset" of the + // same length as "this." + // (For expedience, currently requires the offset to be aligned to the + // bitsize of a uintptr_t. This should go away in the future though it + // will probably remain a good case to optimize.) + void set_intersection_at_offset(BitMap bits, idx_t offset); + void set_from(BitMap bits); bool is_same(BitMap bits); @@ -248,58 +287,13 @@ #endif }; -inline void BitMap::set_bit(idx_t bit) { - verify_index(bit); - *word_addr(bit) |= bit_mask(bit); -} - -inline void BitMap::clear_bit(idx_t bit) { - verify_index(bit); - *word_addr(bit) &= ~bit_mask(bit); -} - -inline void BitMap::set_range(idx_t beg, idx_t end, RangeSizeHint hint) { - if (hint == small_range && end - beg == 1) { - set_bit(beg); - } else { - if (hint == large_range) { - set_large_range(beg, end); - } else { - set_range(beg, end); - } - } -} - -inline void BitMap::clear_range(idx_t beg, idx_t end, RangeSizeHint hint) { - if (hint == small_range && end - beg == 1) { - clear_bit(beg); - } else { - if (hint == large_range) { - clear_large_range(beg, end); - } else { - clear_range(beg, end); - } - } -} - -inline void BitMap::par_set_range(idx_t beg, idx_t end, RangeSizeHint hint) { - if (hint == small_range && end - beg == 1) { - par_at_put(beg, true); - } else { - if (hint == large_range) { - par_at_put_large_range(beg, end, true); - } else { - par_at_put_range(beg, end, true); - } - } -} - // Convenience class wrapping BitMap which provides multiple bits per slot. class BitMap2D VALUE_OBJ_CLASS_SPEC { public: - typedef size_t idx_t; // Type used for bit and word indices. - + typedef BitMap::idx_t idx_t; // Type used for bit and word indices. + typedef BitMap::bm_word_t bm_word_t; // Element type of array that + // represents the bitmap. private: BitMap _map; idx_t _bits_per_slot; @@ -314,7 +308,7 @@ public: // Construction. bits_per_slot must be greater than 0. - BitMap2D(uintptr_t* map, idx_t size_in_slots, idx_t bits_per_slot); + BitMap2D(bm_word_t* map, idx_t size_in_slots, idx_t bits_per_slot); // Allocates necessary data structure in resource area. bits_per_slot must be greater than 0. BitMap2D(idx_t size_in_slots, idx_t bits_per_slot); @@ -359,38 +353,14 @@ _map.at_put_grow(bit_index(slot_index, bit_within_slot_index), value); } - void clear() { - _map.clear(); - } + void clear(); }; +// Closure for iterating over BitMaps - -inline void BitMap::set_range_of_words(idx_t beg, idx_t end) { - uintptr_t* map = _map; - for (idx_t i = beg; i < end; ++i) map[i] = ~(uintptr_t)0; -} - - -inline void BitMap::clear_range_of_words(idx_t beg, idx_t end) { - uintptr_t* map = _map; - for (idx_t i = beg; i < end; ++i) map[i] = 0; -} - - -inline void BitMap::clear() { - clear_range_of_words(0, size_in_words()); -} - - -inline void BitMap::par_clear_range(idx_t beg, idx_t end, RangeSizeHint hint) { - if (hint == small_range && end - beg == 1) { - par_at_put(beg, false); - } else { - if (hint == large_range) { - par_at_put_large_range(beg, end, false); - } else { - par_at_put_range(beg, end, false); - } - } -} +class BitMapClosure VALUE_OBJ_CLASS_SPEC { + public: + // Callback when bit in map is set. Should normally return "true"; + // return of false indicates that the bitmap iteration should terminate. + virtual bool do_bit(BitMap::idx_t offset) = 0; +};