diff options
Diffstat (limited to 'deps/v8/src/heap/marking.cc')
| -rw-r--r-- | deps/v8/src/heap/marking.cc | 52 |
1 files changed, 28 insertions, 24 deletions
diff --git a/deps/v8/src/heap/marking.cc b/deps/v8/src/heap/marking.cc index 23fbdd3465..93b5c06a45 100644 --- a/deps/v8/src/heap/marking.cc +++ b/deps/v8/src/heap/marking.cc @@ -28,6 +28,9 @@ void Bitmap::MarkAllBits() { } void Bitmap::SetRange(uint32_t start_index, uint32_t end_index) { + if (start_index >= end_index) return; + end_index--; + unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2; MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index); unsigned int end_cell_index = end_index >> Bitmap::kBitsPerCellLog2; @@ -43,10 +46,11 @@ void Bitmap::SetRange(uint32_t start_index, uint32_t end_index) { base::Relaxed_Store(cell_base + i, ~0u); } // Finally, fill all bits until the end address in the last cell with 1s. - SetBitsInCell<AccessMode::ATOMIC>(end_cell_index, (end_index_mask - 1)); + SetBitsInCell<AccessMode::ATOMIC>(end_cell_index, + end_index_mask | (end_index_mask - 1)); } else { - SetBitsInCell<AccessMode::ATOMIC>(start_cell_index, - end_index_mask - start_index_mask); + SetBitsInCell<AccessMode::ATOMIC>( + start_cell_index, end_index_mask | (end_index_mask - start_index_mask)); } // This fence prevents re-ordering of publishing stores with the mark- // bit setting stores. @@ -54,6 +58,9 @@ void Bitmap::SetRange(uint32_t start_index, uint32_t end_index) { } void Bitmap::ClearRange(uint32_t start_index, uint32_t end_index) { + if (start_index >= end_index) return; + end_index--; + unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2; MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index); @@ -71,10 +78,11 @@ void Bitmap::ClearRange(uint32_t start_index, uint32_t end_index) { base::Relaxed_Store(cell_base + i, 0); } // Finally, set all bits until the end address in the last cell with 0s. - ClearBitsInCell<AccessMode::ATOMIC>(end_cell_index, (end_index_mask - 1)); + ClearBitsInCell<AccessMode::ATOMIC>(end_cell_index, + end_index_mask | (end_index_mask - 1)); } else { - ClearBitsInCell<AccessMode::ATOMIC>(start_cell_index, - (end_index_mask - start_index_mask)); + ClearBitsInCell<AccessMode::ATOMIC>( + start_cell_index, end_index_mask | (end_index_mask - start_index_mask)); } // This fence prevents re-ordering of publishing stores with the mark- // bit clearing stores. @@ -82,6 +90,9 @@ void Bitmap::ClearRange(uint32_t start_index, uint32_t end_index) { } bool Bitmap::AllBitsSetInRange(uint32_t start_index, uint32_t end_index) { + if (start_index >= end_index) return false; + end_index--; + unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2; MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index); @@ -97,21 +108,18 @@ bool Bitmap::AllBitsSetInRange(uint32_t start_index, uint32_t end_index) { for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) { if (cells()[i] != ~0u) return false; } - matching_mask = (end_index_mask - 1); - // Check against a mask of 0 to avoid dereferencing the cell after the - // end of the bitmap. - return (matching_mask == 0) || - ((cells()[end_cell_index] & matching_mask) == matching_mask); + matching_mask = end_index_mask | (end_index_mask - 1); + return ((cells()[end_cell_index] & matching_mask) == matching_mask); } else { - matching_mask = end_index_mask - start_index_mask; - // Check against a mask of 0 to avoid dereferencing the cell after the - // end of the bitmap. - return (matching_mask == 0) || - (cells()[end_cell_index] & matching_mask) == matching_mask; + matching_mask = end_index_mask | (end_index_mask - start_index_mask); + return (cells()[end_cell_index] & matching_mask) == matching_mask; } } bool Bitmap::AllBitsClearInRange(uint32_t start_index, uint32_t end_index) { + if (start_index >= end_index) return true; + end_index--; + unsigned int start_cell_index = start_index >> Bitmap::kBitsPerCellLog2; MarkBit::CellType start_index_mask = 1u << Bitmap::IndexInCell(start_index); @@ -125,15 +133,11 @@ bool Bitmap::AllBitsClearInRange(uint32_t start_index, uint32_t end_index) { for (unsigned int i = start_cell_index + 1; i < end_cell_index; i++) { if (cells()[i]) return false; } - matching_mask = (end_index_mask - 1); - // Check against a mask of 0 to avoid dereferencing the cell after the - // end of the bitmap. - return (matching_mask == 0) || !(cells()[end_cell_index] & matching_mask); + matching_mask = end_index_mask | (end_index_mask - 1); + return !(cells()[end_cell_index] & matching_mask); } else { - matching_mask = end_index_mask - start_index_mask; - // Check against a mask of 0 to avoid dereferencing the cell after the - // end of the bitmap. - return (matching_mask == 0) || !(cells()[end_cell_index] & matching_mask); + matching_mask = end_index_mask | (end_index_mask - start_index_mask); + return !(cells()[end_cell_index] & matching_mask); } } |