--- /dev/null 2019-02-13 16:01:02.292000000 +0300 +++ new/src/share/vm/utilities/align.hpp 2019-02-15 19:03:35.300816052 +0300 @@ -0,0 +1,152 @@ +/* + * Copyright (c) 1997, 2017, 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_UTILITIES_ALIGN_HPP +#define SHARE_VM_UTILITIES_ALIGN_HPP + +#include "utilities/globalDefinitions.hpp" + +// Signed variants of alignment helpers. There are two versions of each, a macro +// for use in places like enum definitions that require compile-time constant +// expressions and a function for all other places so as to get type checking. + +// Using '(what) & ~align_mask(alignment)' to align 'what' down is broken when +// 'alignment' is an unsigned int and 'what' is a wider type. The & operation +// will widen the inverted mask, and not sign extend it, leading to a mask with +// zeros in the most significant bits. The use of align_mask_widened() solves +// this problem. +#define align_mask(alignment) ((alignment) - 1) +#define widen_to_type_of(what, type_carrier) (true ? (what) : (type_carrier)) +#define align_mask_widened(alignment, type_carrier) widen_to_type_of(align_mask(alignment), (type_carrier)) + +#define align_down_(size, alignment) ((size) & ~align_mask_widened((alignment), (size))) + +#define align_up_(size, alignment) (align_down_((size) + align_mask(alignment), (alignment))) + +#define is_aligned_(size, alignment) (((size) & align_mask(alignment)) == 0) + +// Temporary declaration until this file has been restructured. +template +bool is_power_of_2_t(T x) { + return (x != T(0)) && ((x & (x - 1)) == T(0)); +} + +// Helpers to align sizes and check for alignment + +template +inline T align_up(T size, A alignment) { + assert(is_power_of_2_t(alignment), "must be a power of 2"); + + T ret = align_up_(size, alignment); + assert(is_aligned_(ret, alignment), "must be aligned"); + + return ret; +} + +template +inline T align_down(T size, A alignment) { + assert(is_power_of_2_t(alignment), "must be a power of 2"); + + T ret = align_down_(size, alignment); + assert(is_aligned_(ret, alignment), "must be aligned"); + + return ret; +} + +template +inline bool is_aligned(T size, A alignment) { + assert(is_power_of_2_t(alignment), "must be a power of 2"); + + return is_aligned_(size, alignment); +} + +// Align down with a lower bound. If the aligning results in 0, return 'alignment'. +template +inline T align_down_bounded(T size, A alignment) { + A aligned_size = align_down(size, alignment); + return aligned_size > 0 ? aligned_size : alignment; +} + +// Helpers to align pointers and check for alignment. + +template +inline T* align_up(T* ptr, A alignment) { + return (T*)align_up((uintptr_t)ptr, alignment); +} + +template +inline T* align_down(T* ptr, A alignment) { + return (T*)align_down((uintptr_t)ptr, alignment); +} + +template +inline bool is_aligned(T* ptr, A alignment) { + return is_aligned((uintptr_t)ptr, alignment); +} + +// Align metaspace objects by rounding up to natural word boundary +template +inline T align_metadata_size(T size) { + return align_up(size, 1); +} + +// Align objects in the Java Heap by rounding up their size, in HeapWord units. +template +inline T align_object_size(T word_size) { + return align_up(word_size, MinObjAlignment); +} + +inline bool is_object_aligned(size_t word_size) { + return is_aligned(word_size, MinObjAlignment); +} + +inline bool is_object_aligned(const void* addr) { + return is_aligned(addr, MinObjAlignmentInBytes); +} + +// Pad out certain offsets to jlong alignment, in HeapWord units. +template +inline T align_object_offset(T offset) { + return align_up(offset, HeapWordsPerLong); +} + +// Clamp an address to be within a specific page +// 1. If addr is on the page it is returned as is +// 2. If addr is above the page_address the start of the *next* page will be returned +// 3. Otherwise, if addr is below the page_address the start of the page will be returned +template +inline T* clamp_address_in_page(T* addr, T* page_address, size_t page_size) { + if (align_down(addr, page_size) == align_down(page_address, page_size)) { + // address is in the specified page, just return it as is + return addr; + } else if (addr > page_address) { + // address is above specified page, return start of next page + return align_down(page_address, page_size) + page_size; + } else { + // address is below specified page, return start of page + return align_down(page_address, page_size); + } +} + +#endif // SHARE_VM_UTILITIES_ALIGN_HPP