diff --git a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.cpp b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.cpp index c3e8108752f..127e6324fb0 100644 --- a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.cpp +++ b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.cpp @@ -23,7 +23,7 @@ */ #include "precompiled.hpp" -#include "gc/shenandoah/shenandoahSimpleBitMap.hpp" +#include "gc/shenandoah/shenandoahSimpleBitMap.inline.hpp" ShenandoahSimpleBitMap::ShenandoahSimpleBitMap(size_t num_bits) : _num_bits(num_bits), @@ -43,8 +43,8 @@ size_t ShenandoahSimpleBitMap::count_leading_ones(idx_t start_idx) const { assert((start_idx >= 0) && (start_idx < _num_bits), "precondition"); size_t array_idx = start_idx >> LogBitsPerWord; uintx element_bits = _bitmap[array_idx]; - uintx bit_number = start_idx & right_n_bits(LogBitsPerWord); - uintx mask = ~right_n_bits(bit_number); + uintx bit_number = start_idx & (BitsPerWord - 1); + uintx mask = ~tail_mask(bit_number); size_t counted_ones = 0; while ((element_bits & mask) == mask) { // All bits numbered >= bit_number are set @@ -54,7 +54,7 @@ size_t ShenandoahSimpleBitMap::count_leading_ones(idx_t start_idx) const { // Strength reduction: array_idx = (start_idx >> LogBitsPerWord) array_idx++; element_bits = _bitmap[array_idx]; - // Constant folding: bit_number = start_idx & right_n_bits(LogBitsPerWord); + // Constant folding: bit_number = start_idx & (BitsPerWord - 1); bit_number = 0; // Constant folding: mask = ~right_n_bits(bit_number); mask = ~0; @@ -70,9 +70,9 @@ size_t ShenandoahSimpleBitMap::count_trailing_ones(idx_t last_idx) const { assert((last_idx >= 0) && (last_idx < _num_bits), "precondition"); size_t array_idx = last_idx >> LogBitsPerWord; uintx element_bits = _bitmap[array_idx]; - uintx bit_number = last_idx & right_n_bits(LogBitsPerWord); + uintx bit_number = last_idx & (BitsPerWord - 1); // All ones from bit 0 to the_bit - uintx mask = right_n_bits(bit_number + 1); + uintx mask = tail_mask(bit_number + 1); size_t counted_ones = 0; while ((element_bits & mask) == mask) { // All bits numbered <= bit_number are set @@ -81,7 +81,7 @@ size_t ShenandoahSimpleBitMap::count_trailing_ones(idx_t last_idx) const { // Dead code: do not need to compute: last_idx -= found_ones; array_idx--; element_bits = _bitmap[array_idx]; - // Constant folding: bit_number = last_idx & right_n_bits(LogBitsPerWord); + // Constant folding: bit_number = last_idx & (BitsPerWord - 1); bit_number = BitsPerWord - 1; // Constant folding: mask = right_n_bits(bit_number + 1); mask = ~0; @@ -99,7 +99,7 @@ bool ShenandoahSimpleBitMap::is_forward_consecutive_ones(idx_t start_idx, idx_t start_idx, count); assert(start_idx + count <= (idx_t) _num_bits, "precondition"); size_t array_idx = start_idx >> LogBitsPerWord; - uintx bit_number = start_idx & right_n_bits(LogBitsPerWord); + uintx bit_number = start_idx & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; uintx bits_to_examine = BitsPerWord - bit_number; element_bits >>= bit_number; @@ -128,7 +128,7 @@ bool ShenandoahSimpleBitMap::is_backward_consecutive_ones(idx_t last_idx, idx_t assert((last_idx >= 0) && (last_idx < _num_bits), "precondition"); assert(last_idx - count >= -1, "precondition"); size_t array_idx = last_idx >> LogBitsPerWord; - uintx bit_number = last_idx & right_n_bits(LogBitsPerWord); + uintx bit_number = last_idx & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; uintx bits_to_examine = bit_number + 1; element_bits <<= (BitsPerWord - bits_to_examine); @@ -161,10 +161,10 @@ idx_t ShenandoahSimpleBitMap::find_first_consecutive_set_bits(idx_t beg, idx_t e return end; } uintx array_idx = beg >> LogBitsPerWord; - uintx bit_number = beg & right_n_bits(LogBitsPerWord); + uintx bit_number = beg & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; if (bit_number > 0) { - uintx mask_out = right_n_bits(bit_number); + uintx mask_out = tail_mask(bit_number); element_bits &= ~mask_out; } @@ -222,9 +222,9 @@ idx_t ShenandoahSimpleBitMap::find_first_consecutive_set_bits(idx_t beg, idx_t e } array_idx = beg >> LogBitsPerWord; element_bits = _bitmap[array_idx]; - bit_number = beg & right_n_bits(LogBitsPerWord); + bit_number = beg & (BitsPerWord - 1); if (bit_number > 0) { - size_t mask_out = right_n_bits(bit_number); + size_t mask_out = tail_mask(bit_number); element_bits &= ~mask_out; } } @@ -242,10 +242,10 @@ idx_t ShenandoahSimpleBitMap::find_last_consecutive_set_bits(const idx_t beg, id } size_t array_idx = end >> LogBitsPerWord; - uintx bit_number = end & right_n_bits(LogBitsPerWord); + uintx bit_number = end & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; if (bit_number < BitsPerWord - 1) { - uintx mask_in = right_n_bits(bit_number + 1); + uintx mask_in = tail_mask(bit_number + 1); element_bits &= mask_in; } @@ -280,10 +280,10 @@ idx_t ShenandoahSimpleBitMap::find_last_consecutive_set_bits(const idx_t beg, id return beg; } array_idx = end >> LogBitsPerWord; - bit_number = end & right_n_bits(LogBitsPerWord); + bit_number = end & (BitsPerWord - 1); element_bits = _bitmap[array_idx]; if (bit_number < BitsPerWord - 1){ - size_t mask_in = right_n_bits(bit_number + 1); + size_t mask_in = tail_mask(bit_number + 1); element_bits &= mask_in; } } diff --git a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.hpp b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.hpp index c22e9527002..6b95303fb33 100644 --- a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.hpp +++ b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.hpp @@ -50,7 +50,7 @@ typedef ssize_t idx_t; // ShenandoahSimpleBitMap resembles CHeapBitMap but adds missing support for find_first_consecutive_set_bits() and // find_last_consecutive_set_bits. An alternative refactoring of code would subclass CHeapBitMap, but this might // break abstraction rules, because efficient implementation requires assumptions about superclass internals that -// might be violatee through future software maintenance. +// might be violated through future software maintenance. class ShenandoahSimpleBitMap { const idx_t _num_bits; const size_t _num_words; @@ -84,7 +84,7 @@ class ShenandoahSimpleBitMap { inline idx_t aligned_index(idx_t idx) const { assert((idx >= 0) && (idx < _num_bits), "precondition"); - idx_t array_idx = idx & ~right_n_bits(LogBitsPerWord); + idx_t array_idx = idx & ~(BitsPerWord - 1); return array_idx; } @@ -107,7 +107,7 @@ class ShenandoahSimpleBitMap { inline void set_bit(idx_t idx) { assert((idx >= 0) && (idx < _num_bits), "precondition"); size_t array_idx = idx >> LogBitsPerWord; - uintx bit_number = idx & right_n_bits(LogBitsPerWord); + uintx bit_number = idx & (BitsPerWord - 1); uintx the_bit = nth_bit(bit_number); _bitmap[array_idx] |= the_bit; } @@ -116,7 +116,7 @@ class ShenandoahSimpleBitMap { assert((idx >= 0) && (idx < _num_bits), "precondition"); assert(idx >= 0, "precondition"); size_t array_idx = idx >> LogBitsPerWord; - uintx bit_number = idx & right_n_bits(LogBitsPerWord); + uintx bit_number = idx & (BitsPerWord - 1); uintx the_bit = nth_bit(bit_number); _bitmap[array_idx] &= ~the_bit; } @@ -125,9 +125,9 @@ class ShenandoahSimpleBitMap { assert((idx >= 0) && (idx < _num_bits), "precondition"); assert(idx >= 0, "precondition"); size_t array_idx = idx >> LogBitsPerWord; - uintx bit_number = idx & right_n_bits(LogBitsPerWord); + uintx bit_number = idx & (BitsPerWord - 1); uintx the_bit = nth_bit(bit_number); - return (_bitmap[array_idx] & the_bit)? true: false; + return (_bitmap[array_idx] & the_bit) != 0; } // Return the index of the first set bit in the range [beg, size()), or size() if none found. diff --git a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.inline.hpp b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.inline.hpp index 3e602ed11e0..c047e1ed663 100644 --- a/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.inline.hpp +++ b/src/hotspot/share/gc/shenandoah/shenandoahSimpleBitMap.inline.hpp @@ -27,15 +27,22 @@ #include "gc/shenandoah/shenandoahSimpleBitMap.hpp" +inline uintx tail_mask(uintx bit_number) { + if (bit_number >= BitsPerWord) { + return -1; + } + return (uintx(1) << bit_number) - 1; +} + inline idx_t ShenandoahSimpleBitMap::find_first_set_bit(idx_t beg, idx_t end) const { assert((beg >= 0) && (beg < _num_bits), "precondition"); assert((end > beg) && (end <= _num_bits), "precondition"); do { size_t array_idx = beg >> LogBitsPerWord; - uintx bit_number = beg & right_n_bits(LogBitsPerWord); + uintx bit_number = beg & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; if (bit_number > 0) { - uintx mask_out = right_n_bits(bit_number); + uintx mask_out = tail_mask(bit_number); element_bits &= ~mask_out; } if (element_bits) { @@ -62,10 +69,10 @@ inline idx_t ShenandoahSimpleBitMap::find_last_set_bit(idx_t beg, idx_t end) con assert((beg >= -1) && (beg < end), "precondition"); do { idx_t array_idx = end >> LogBitsPerWord; - uintx bit_number = end & right_n_bits(LogBitsPerWord); + uint8_t bit_number = end & (BitsPerWord - 1); uintx element_bits = _bitmap[array_idx]; if (bit_number < BitsPerWord - 1){ - uintx mask_in = right_n_bits(bit_number + 1); + uintx mask_in = tail_mask(bit_number + 1); element_bits &= mask_in; } if (element_bits) {