| /* |
| * Copyright (c) 2009, 2011, 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. |
| */ |
| package org.graalvm.compiler.lir; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| import java.util.List; |
| |
| /** |
| * A buffer to enqueue updates to a list. This avoids frequent re-sizing of the list and copying of |
| * list elements when insertions are done at multiple positions of the list. Additionally, it |
| * ensures that the list is not modified while it is, e.g., iterated, and instead only modified once |
| * after the iteration is done. |
| * <p> |
| * The buffer uses internal data structures to store the enqueued updates. To avoid allocations, a |
| * buffer can be re-used. Call the methods in the following order: {@link #init}, {@link #append}, |
| * {@link #append}, ..., {@link #finish()}, {@link #init}, ... |
| * <p> |
| * Note: This class does not depend on LIRInstruction, so we could make it a generic utility class. |
| */ |
| public final class LIRInsertionBuffer { |
| |
| /** |
| * The lir list where ops of this buffer should be inserted later (null when uninitialized). |
| */ |
| private List<LIRInstruction> lir; |
| |
| /** |
| * List of insertion points. index and count are stored alternately: indexAndCount[i * 2]: the |
| * index into lir list where "count" ops should be inserted indexAndCount[i * 2 + 1]: the number |
| * of ops to be inserted at index |
| */ |
| private int[] indexAndCount; |
| private int indexAndCountSize; |
| |
| /** |
| * The LIROps to be inserted. |
| */ |
| private final List<LIRInstruction> ops; |
| |
| public LIRInsertionBuffer() { |
| indexAndCount = new int[8]; |
| ops = new ArrayList<>(4); |
| } |
| |
| /** |
| * Initialize this buffer. This method must be called before using {@link #append}. |
| */ |
| public void init(List<LIRInstruction> newLir) { |
| assert !initialized() : "already initialized"; |
| assert indexAndCountSize == 0 && ops.size() == 0; |
| this.lir = newLir; |
| } |
| |
| public boolean initialized() { |
| return lir != null; |
| } |
| |
| public List<LIRInstruction> lirList() { |
| return lir; |
| } |
| |
| /** |
| * Enqueue a new instruction that will be appended to the instruction list when |
| * {@link #finish()} is called. The new instruction is added <b>before</b> the existing |
| * instruction with the given index. This method can only be called with increasing values of |
| * index, e.g., once an instruction was appended with index 4, subsequent instructions can only |
| * be appended with index 4 or higher. |
| */ |
| public void append(int index, LIRInstruction op) { |
| int i = numberOfInsertionPoints() - 1; |
| if (i < 0 || indexAt(i) < index) { |
| appendNew(index, 1); |
| } else { |
| assert indexAt(i) == index : "can append LIROps in ascending order only"; |
| assert countAt(i) > 0 : "check"; |
| setCountAt(i, countAt(i) + 1); |
| } |
| ops.add(op); |
| |
| assert verify(); |
| } |
| |
| /** |
| * Append all enqueued instructions to the instruction list. After that, {@link #init(List)} can |
| * be called again to re-use this buffer. |
| */ |
| public void finish() { |
| if (ops.size() > 0) { |
| int n = lir.size(); |
| // increase size of instructions list |
| for (int i = 0; i < ops.size(); i++) { |
| lir.add(null); |
| } |
| // insert ops from buffer into instructions list |
| int opIndex = ops.size() - 1; |
| int ipIndex = numberOfInsertionPoints() - 1; |
| int fromIndex = n - 1; |
| int toIndex = lir.size() - 1; |
| while (ipIndex >= 0) { |
| int index = indexAt(ipIndex); |
| // make room after insertion point |
| while (fromIndex >= index) { |
| lir.set(toIndex--, lir.get(fromIndex--)); |
| } |
| // insert ops from buffer |
| for (int i = countAt(ipIndex); i > 0; i--) { |
| lir.set(toIndex--, ops.get(opIndex--)); |
| } |
| ipIndex--; |
| } |
| indexAndCountSize = 0; |
| ops.clear(); |
| } |
| lir = null; |
| } |
| |
| private void appendNew(int index, int count) { |
| int oldSize = indexAndCountSize; |
| int newSize = oldSize + 2; |
| if (newSize > this.indexAndCount.length) { |
| indexAndCount = Arrays.copyOf(indexAndCount, newSize * 2); |
| } |
| indexAndCount[oldSize] = index; |
| indexAndCount[oldSize + 1] = count; |
| this.indexAndCountSize = newSize; |
| } |
| |
| private void setCountAt(int i, int value) { |
| indexAndCount[(i << 1) + 1] = value; |
| } |
| |
| private int numberOfInsertionPoints() { |
| assert indexAndCount.length % 2 == 0 : "must have a count for each index"; |
| return indexAndCountSize >> 1; |
| } |
| |
| private int indexAt(int i) { |
| return indexAndCount[(i << 1)]; |
| } |
| |
| private int countAt(int i) { |
| return indexAndCount[(i << 1) + 1]; |
| } |
| |
| private boolean verify() { |
| int sum = 0; |
| int prevIdx = -1; |
| |
| for (int i = 0; i < numberOfInsertionPoints(); i++) { |
| assert prevIdx < indexAt(i) : "index must be ordered ascending"; |
| sum += countAt(i); |
| } |
| assert sum == ops.size() : "wrong total sum"; |
| return true; |
| } |
| } |