de.mirkosertic.bytecoder.classlib.MemoryManager Maven / Gradle / Ivy
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/*
* Copyright 2017 Mirko Sertic
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package de.mirkosertic.bytecoder.classlib;
import de.mirkosertic.bytecoder.api.Export;
/**
* A simple Memory Manager.
*
* It basically holds two linked lists. One for the free memory blocks,
* and one for the reserved blocks.
*/
public class MemoryManager {
public static native int log(int amount);
@Export("initMemory")
public static void initNative() {
initInternal(Address.getMemorySize());
}
private static void initInternal(final int aSize) {
// This is the list of free blocks
final int heapBase = Address.getHeapBase();
final int initialFreeBlock = heapBase + 36;
Address.setIntValue(heapBase, 4, initialFreeBlock);
// Free memory block
Address.setIntValue(initialFreeBlock, 0, aSize - 48 - heapBase);
Address.setIntValue(initialFreeBlock, 4, 0);
Address.setIntValue(initialFreeBlock, 8, 0);
// This is the List of reserved blocks
Address.setIntValue(heapBase, 8, 0);
// Current work counter for GC resumes
Address.setIntValue(heapBase, 12, 0);
// Current counter for GC epochs
Address.setIntValue(heapBase, 16, 1);
}
@Export("GCEpoch")
public static int getGCEpoch() {
final int heapBase = Address.getHeapBase();
return Address.getIntValue(heapBase, 16);
}
@Export("freeMem")
public static int freeMem() {
int resultSize = 0;
final int heapBase = Address.getHeapBase();
int current = Address.getIntValue(heapBase, 4);
while (current != 0) {
resultSize += Address.getIntValue(current, 0);
current = Address.getIntValue(current, 4);
}
return resultSize;
}
@Export("usedMem")
public static int usedMem() {
int resultSize = 0;
final int heapBase = Address.getHeapBase();
int current = Address.getIntValue(heapBase, 8);
while (current != 0) {
resultSize += Address.getIntValue(current, 0);
current = Address.getIntValue(current, 4);
}
return resultSize;
}
private static void internalFree(final int current) {
final int heapBase = Address.getHeapBase();
final int currentPrev = Address.getIntValue(current, 12);
final int currentNext = Address.getIntValue(current, 4);
if (currentPrev != 0) {
Address.setIntValue(currentPrev, 4, currentNext);
} else {
Address.setIntValue(heapBase, 8, currentNext);
}
if (currentNext != 0) {
Address.setIntValue(currentNext, 12, currentPrev);
}
// Prepend to the list of free blocks
final int freeListHead = Address.getIntValue(heapBase, 4);
Address.setIntValue(current, 4, freeListHead);
Address.setIntValue(freeListHead, 12, current);
Address.setIntValue(current, 12, 0);
Address.setIntValue(heapBase, 4, current);
}
@Export("free")
public static void free(final int aPointer) {
final int pointerToBlock = aPointer - 16;
internalFree(pointerToBlock);
}
@Export("malloc")
public static int malloc(int aSize) {
// Overhead for header
aSize+=16;
final int heapBase = Address.getHeapBase();
int current = Address.getIntValue(heapBase, 4);
while (current != 0) {
final int currentSize = Address.getIntValue(current, 0);
final int currentPrev = Address.getIntValue(current, 12);
final int currentNext = Address.getIntValue(current, 4);
if (currentSize >= aSize) {
final int remaining = currentSize - aSize;
if (remaining < 16) {
// We have an exact match
final int allocatedListHead = Address.getIntValue(heapBase, 8);
final int allocated = current;
Address.setIntValue(allocated, 0, currentSize);
Address.setIntValue(allocated, 4, allocatedListHead);
Address.setIntValue(allocated, 8, 1);
Address.setIntValue(allocated,12, 0);
if (allocatedListHead != 0) {
Address.setIntValue(allocatedListHead, 12, allocated);
}
Address.setIntValue(heapBase, 8, allocated);
if (currentPrev != 0) {
Address.setIntValue(currentPrev, 4, currentNext);
} else {
Address.setIntValue(heapBase, 4, currentNext);
}
if (currentNext != 0) {
Address.setIntValue(currentNext,12, currentPrev);
}
// Wipeout data
final int dataStart = allocated + 16;
final int fillSize = aSize - 16;
if (fillSize == 0) {
/// Nothing to do
} else if (fillSize == 4) {
Address.setIntValue(dataStart, 0, 0);
} else if (fillSize == 8) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
} else if (fillSize == 12) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
} else if (fillSize == 16) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
} else if (fillSize == 20) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
} else if (fillSize == 24) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
Address.setIntValue(dataStart, 20, 0);
} else if (fillSize == 28) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
Address.setIntValue(dataStart, 20, 0);
Address.setIntValue(dataStart, 24, 0);
} else {
for (int i = 0; i < fillSize; i += 4) {
Address.setIntValue(dataStart, i, 0);
}
}
return dataStart;
}
if (remaining > 16) {
// We can use split this chunk
// We create the allocated chunk by appending it to the list of
// allocated blocks
final int allocatedListHead = Address.getIntValue(heapBase, 8);
final int allocated = current;
Address.setIntValue(allocated, 0, aSize);
Address.setIntValue(allocated, 4, allocatedListHead);
Address.setIntValue(allocated, 8, 1);
Address.setIntValue(allocated, 12, 0);
if (allocatedListHead != 0) {
Address.setIntValue(allocatedListHead, 12, allocated);
}
Address.setIntValue(heapBase, 8, allocated);
// Now we split the original block
if (currentPrev != 0) {
final int newFree = current + aSize;
Address.setIntValue(newFree, 0, remaining);
Address.setIntValue(newFree, 4, currentNext);
Address.setIntValue(newFree, 8, 1);
Address.setIntValue(newFree, 12, currentPrev);
if (currentPrev != 0) {
Address.setIntValue(currentPrev, 4, newFree);
}
if (currentNext != 0) {
Address.setIntValue(currentNext, 12, newFree);
}
} else {
final int newFree = current + aSize;
Address.setIntValue(newFree, 0, remaining);
Address.setIntValue(newFree, 4, currentNext);
Address.setIntValue(newFree, 8, 1);
Address.setIntValue(newFree, 12, 0);
if (currentNext != 0) {
Address.setIntValue(currentNext, 12, newFree);
}
Address.setIntValue(heapBase, 4, newFree);
}
// Wipeout data
final int dataStart = allocated + 16;
final int fillSize = aSize - 16;
if (fillSize == 0) {
/// Nothing to do
} else if (fillSize == 4) {
Address.setIntValue(dataStart, 0, 0);
} else if (fillSize == 8) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
} else if (fillSize == 12) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
} else if (fillSize == 16) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
} else if (fillSize == 20) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
} else if (fillSize == 24) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
Address.setIntValue(dataStart, 20, 0);
} else if (fillSize == 28) {
Address.setIntValue(dataStart, 0, 0);
Address.setIntValue(dataStart, 4, 0);
Address.setIntValue(dataStart, 8, 0);
Address.setIntValue(dataStart, 12, 0);
Address.setIntValue(dataStart, 16, 0);
Address.setIntValue(dataStart, 20, 0);
Address.setIntValue(dataStart, 24, 0);
} else {
for (int i = 0; i < fillSize; i += 4) {
Address.setIntValue(dataStart, i, 0);
}
}
return dataStart;
}
}
current = Address.getIntValue(current, 4);
}
Address.unreachable();
return -1;
}
@Export("newObject")
public static int newObject(final int aSize, final int aType, final int aVTableIndex) {
final int allocated = malloc(aSize);
Address.setIntValue(allocated, 0, aType);
Address.setIntValue(allocated, 4, aVTableIndex);
return allocated;
}
public static void initStackObject(final int aPtr, final int aSize, final int aType, final int aVTableIndex) {
// Wipeout data
for (int i=0;i= blockLimit) {
// We have reached the limit for the current run
// We save the next block to proceed and exit here
Address.setIntValue(heapBase, 12, next);
return stepCounter;
}
}
current = next;
}
// Increment epoch
Address.setIntValue(heapBase, 16, currentEpoch + 1);
// The next run starts at the beginning
Address.setIntValue(heapBase, 12, 0);
return freeCounter;
}
@Export("newArrayINTINTINT")
public static int newArray(final int aSize, final int aType, final int aVTableIndex) {
// Arrays are normal objects. Their data are a length field plus n * data
final int newArray = newObject(16 + 4 + 8 * aSize, aType, aVTableIndex);
Address.setIntValue(newArray, 16, aSize);
return newArray;
}
@Export("newArrayINTINTINTINT")
public static int newArray(final int aSize1, final int aSize2, final int aType, final int aVTableIndex) {
final int newArray = newArray(aSize1, aType, aVTableIndex);
for (int i=0;i © 2015 - 2025 Weber Informatics LLC | Privacy Policy