| /* |
| * 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 <typename T> |
| 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 <typename T, typename A> |
| inline T align_up(T size, A alignment) { |
| assert(is_power_of_2_t(alignment), "must be a power of 2: " UINT64_FORMAT, (uint64_t)alignment); |
| |
| T ret = align_up_(size, alignment); |
| assert(is_aligned_(ret, alignment), "must be aligned: " UINT64_FORMAT, (uint64_t)ret); |
| |
| return ret; |
| } |
| |
| template <typename T, typename A> |
| inline T align_down(T size, A alignment) { |
| assert(is_power_of_2_t(alignment), "must be a power of 2: " UINT64_FORMAT, (uint64_t)alignment); |
| |
| T ret = align_down_(size, alignment); |
| assert(is_aligned_(ret, alignment), "must be aligned: " UINT64_FORMAT, (uint64_t)ret); |
| |
| return ret; |
| } |
| |
| template <typename T, typename A> |
| inline bool is_aligned(T size, A alignment) { |
| assert(is_power_of_2_t(alignment), "must be a power of 2: " UINT64_FORMAT, (uint64_t)alignment); |
| |
| return is_aligned_(size, alignment); |
| } |
| |
| // Align down with a lower bound. If the aligning results in 0, return 'alignment'. |
| template <typename T, typename A> |
| 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 <typename T, typename A> |
| inline T* align_up(T* ptr, A alignment) { |
| return (T*)align_up((uintptr_t)ptr, alignment); |
| } |
| |
| template <typename T, typename A> |
| inline T* align_down(T* ptr, A alignment) { |
| return (T*)align_down((uintptr_t)ptr, alignment); |
| } |
| |
| template <typename T, typename A> |
| 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 <typename T> |
| 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 <typename T> |
| 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 <typename T> |
| 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 <typename T> |
| 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 |