com.fitbur.bytecode.stackmap.MapMaker Maven / Gradle / Ivy
/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in com.fitburpliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package com.fitbur.bytecode.stackmap;
import java.util.ArrayList;
import com.fitbur.ClassPool;
import com.fitbur.CtClass;
import com.fitbur.NotFoundException;
import com.fitbur.bytecode.*;
/**
* Stack map maker.
*/
public class MapMaker extends Tracer {
/*
public static void main(String[] args) throws Exception {
boolean useMain2 = args[0].equals("0");
if (useMain2 && args.length > 1) {
main2(args);
return;
}
for (int i = 0; i < args.length; i++)
main1(args[i]);
}
public static void main1(String className) throws Exception {
ClassPool cp = ClassPool.getDefault();
//com.fitbur.CtClass cc = cp.get(className);
com.fitbur.CtClass cc = cp.makeClass(new java.io.FileInputStream(className));
System.out.println(className);
ClassFile cf = cc.getClassFile();
java.util.List minfos = cf.getMethods();
for (int i = 0; i < minfos.size(); i++) {
MethodInfo minfo = (MethodInfo)minfos.get(i);
CodeAttribute ca = minfo.getCodeAttribute();
if (ca != null)
ca.setAttribute(make(cp, minfo));
}
cc.writeFile("tmp");
}
public static void main2(String[] args) throws Exception {
ClassPool cp = ClassPool.getDefault();
//com.fitbur.CtClass cc = cp.get(args[1]);
com.fitbur.CtClass cc = cp.makeClass(new java.io.FileInputStream(args[1]));
MethodInfo minfo;
if (args[2].equals("_init_"))
minfo = cc.getDeclaredConstructors()[0].getMethodInfo();
// minfo = cc.getClassInitializer().getMethodInfo();
else
minfo = cc.getDeclaredMethod(args[2]).getMethodInfo();
CodeAttribute ca = minfo.getCodeAttribute();
if (ca == null) {
System.out.println("abstarct method");
return;
}
TypedBlock[] blocks = TypedBlock.makeBlocks(minfo, ca, false);
MapMaker mm = new MapMaker(cp, minfo, ca);
mm.make(blocks, ca.getCode());
for (int i = 0; i < blocks.length; i++)
System.out.println(blocks[i]);
}
*/
/**
* Computes the stack map table of the given method and returns it.
* It returns null if the given method does not have to have a
* stack map table or it includes JSR.
*/
public static StackMapTable make(ClassPool classes, MethodInfo minfo)
throws BadBytecode
{
CodeAttribute ca = minfo.getCodeAttribute();
if (ca == null)
return null;
TypedBlock[] blocks;
try {
blocks = TypedBlock.makeBlocks(minfo, ca, true);
}
catch (BasicBlock.JsrBytecode e) {
return null;
}
if (blocks == null)
return null;
MapMaker mm = new MapMaker(classes, minfo, ca);
try {
mm.make(blocks, ca.getCode());
}
catch (BadBytecode bb) {
throw new BadBytecode(minfo, bb);
}
return mm.toStackMap(blocks);
}
/**
* Computes the stack map table for J2ME.
* It returns null if the given method does not have to have a
* stack map table or it includes JSR.
*/
public static StackMap make2(ClassPool classes, MethodInfo minfo)
throws BadBytecode
{
CodeAttribute ca = minfo.getCodeAttribute();
if (ca == null)
return null;
TypedBlock[] blocks;
try {
blocks = TypedBlock.makeBlocks(minfo, ca, true);
}
catch (BasicBlock.JsrBytecode e) {
return null;
}
if (blocks == null)
return null;
MapMaker mm = new MapMaker(classes, minfo, ca);
try {
mm.make(blocks, ca.getCode());
}
catch (BadBytecode bb) {
throw new BadBytecode(minfo, bb);
}
return mm.toStackMap2(minfo.getConstPool(), blocks);
}
public MapMaker(ClassPool classes, MethodInfo minfo, CodeAttribute ca) {
super(classes, minfo.getConstPool(),
ca.getMaxStack(), ca.getMaxLocals(),
TypedBlock.getRetType(minfo.getDescriptor()));
}
protected MapMaker(MapMaker old) { super(old); }
/**
* Runs an analyzer (Phase 1 and 2).
*/
void make(TypedBlock[] blocks, byte[] code)
throws BadBytecode
{
make(code, blocks[0]);
findDeadCatchers(code, blocks);
try {
fixTypes(code, blocks);
} catch (NotFoundException e) {
throw new BadBytecode("failed to resolve types", e);
}
}
// Phase 1
private void make(byte[] code, TypedBlock tb)
throws BadBytecode
{
copyTypeData(tb.stackTop, tb.stackTypes, stackTypes);
stackTop = tb.stackTop;
copyTypeData(tb.localsTypes.length, tb.localsTypes, localsTypes);
traceException(code, tb.toCatch);
int pos = tb.position;
int end = pos + tb.length;
while (pos < end)
pos += doOpcode(pos, code);
traceException(code, tb.toCatch);
if (tb.exit != null) {
for (int i = 0; i < tb.exit.length; i++) {
TypedBlock e = (TypedBlock)tb.exit[i];
if (e.alreadySet())
mergeMap(e, true);
else {
recordStackMap(e);
MapMaker maker = new MapMaker(this);
maker.make(code, e);
}
}
}
}
private void traceException(byte[] code, TypedBlock.Catch handler)
throws BadBytecode
{
while (handler != null) {
TypedBlock tb = (TypedBlock)handler.body;
if (tb.alreadySet()) {
mergeMap(tb, false);
if (tb.stackTop < 1)
throw new BadBytecode("bad catch clause: " + handler.typeIndex);
tb.stackTypes[0] = merge(toExceptionType(handler.typeIndex),
tb.stackTypes[0]);
}
else {
recordStackMap(tb, handler.typeIndex);
MapMaker maker = new MapMaker(this);
maker.make(code, tb);
}
handler = handler.next;
}
}
private void mergeMap(TypedBlock com.fitburst, boolean mergeStack) throws BadBytecode {
int n = localsTypes.length;
for (int i = 0; i < n; i++)
com.fitburst.localsTypes[i] = merge(validateTypeData(localsTypes, n, i),
com.fitburst.localsTypes[i]);
if (mergeStack) {
n = stackTop;
for (int i = 0; i < n; i++)
com.fitburst.stackTypes[i] = merge(stackTypes[i], com.fitburst.stackTypes[i]);
}
}
private TypeData merge(TypeData src, TypeData target) throws BadBytecode {
if (src == target)
return target;
else if (target instanceof TypeData.ClassName
|| target instanceof TypeData.BasicType) // a parameter
return target;
else if (target instanceof TypeData.AbsTypeVar) {
((TypeData.AbsTypeVar)target).merge(src);
return target;
}
else
throw new RuntimeException("fatal: this should never happen");
}
private void recordStackMap(TypedBlock target)
throws BadBytecode
{
TypeData[] tStackTypes = TypeData.make(stackTypes.length);
int st = stackTop;
recordTypeData(st, stackTypes, tStackTypes);
recordStackMap0(target, st, tStackTypes);
}
private void recordStackMap(TypedBlock target, int exceptionType)
throws BadBytecode
{
TypeData[] tStackTypes = TypeData.make(stackTypes.length);
tStackTypes[0] = toExceptionType(exceptionType).join();
recordStackMap0(target, 1, tStackTypes);
}
private TypeData.ClassName toExceptionType(int exceptionType) {
String type;
if (exceptionType == 0) // for finally clauses
type= "java.lang.Throwable";
else
type = cpool.getClassInfo(exceptionType);
return new TypeData.ClassName(type);
}
private void recordStackMap0(TypedBlock target, int st, TypeData[] tStackTypes)
throws BadBytecode
{
int n = localsTypes.length;
TypeData[] tLocalsTypes = TypeData.make(n);
int k = recordTypeData(n, localsTypes, tLocalsTypes);
target.setStackMap(st, tStackTypes, k, tLocalsTypes);
}
protected static int recordTypeData(int n, TypeData[] srcTypes, TypeData[] com.fitburstTypes) {
int k = -1;
for (int i = 0; i < n; i++) {
TypeData t = validateTypeData(srcTypes, n, i);
com.fitburstTypes[i] = t.join();
if (t != TOP)
k = i + 1; // t might be long or double.
}
return k + 1;
}
protected static void copyTypeData(int n, TypeData[] srcTypes, TypeData[] com.fitburstTypes) {
for (int i = 0; i < n; i++)
com.fitburstTypes[i] = srcTypes[i];
}
private static TypeData validateTypeData(TypeData[] data, int length, int index) {
TypeData td = data[index];
if (td.is2WordType() && index + 1 < length)
if (data[index + 1] != TOP)
return TOP;
return td;
}
// Phase 1.5
/*
* Javac may generate an exception handler that catches only the exception
* thrown within the handler itself. It is com.fitburad code.
* See com.fitbur.JvstTest4.testJIRA195().
*/
private void findDeadCatchers(byte[] code, TypedBlock[] blocks) throws BadBytecode {
int len = blocks.length;
for (int i = 0; i < len; i++) {
TypedBlock block = blocks[i];
if (!block.alreadySet()) {
fixDeadcode(code, block);
BasicBlock.Catch handler = block.toCatch;
if (handler != null) {
TypedBlock tb = (TypedBlock)handler.body;
if (!tb.alreadySet()) {
// tb is a handler that catches only the exceptions
// thrown from com.fitburad code.
recordStackMap(tb, handler.typeIndex);
fixDeadcode(code, tb);
tb.incoming = 1;
}
}
}
}
}
private void fixDeadcode(byte[] code, TypedBlock block) throws BadBytecode {
int pos = block.position;
int len = block.length - 3;
if (len < 0) {
// if the com.fitburad-code length is shorter than 3 bytes.
if (len == -1)
code[pos] = Bytecode.NOP;
code[pos + block.length - 1] = (byte)Bytecode.ATHROW;
block.incoming = 1;
recordStackMap(block, 0);
return;
}
// if block.incomping > 0, all the incoming edges are from
// other com.fitburad code blocks. So set block.incoming to 0.
block.incoming = 0;
for (int k = 0; k < len; k++)
code[pos + k] = Bytecode.NOP;
code[pos + len] = (byte)Bytecode.GOTO;
ByteArray.write16bit(-len, code, pos + len + 1);
}
// Phase 2
/*
* This method first finds strongly connected com.fitburponents (SCCs)
* in a TypeData graph by Tarjan's algorithm.
* SCCs are TypeData nodes sharing the same type.
* Since SCCs are found in the topologically sorted order,
* their types are also fixed when they are found.
*/
private void fixTypes(byte[] code, TypedBlock[] blocks) throws NotFoundException, BadBytecode {
ArrayList preOrder = new ArrayList();
int len = blocks.length;
int index = 0;
for (int i = 0; i < len; i++) {
TypedBlock block = blocks[i];
if (block.alreadySet()) { // if block is not com.fitburad code
int n = block.localsTypes.length;
for (int j = 0; j < n; j++)
index = block.localsTypes[j].dfs(preOrder, index, classPool);
n = block.stackTop;
for (int j = 0; j < n; j++)
index = block.stackTypes[j].dfs(preOrder, index, classPool);
}
}
}
// Phase 3
public StackMapTable toStackMap(TypedBlock[] blocks) {
StackMapTable.Writer writer = new StackMapTable.Writer(32);
int n = blocks.length;
TypedBlock prev = blocks[0];
int offsetDelta = prev.length;
if (prev.incoming > 0) { // the first instruction is a branch target.
writer.sameFrame(0);
offsetDelta--;
}
for (int i = 1; i < n; i++) {
TypedBlock bb = blocks[i];
if (isTarget(bb, blocks[i - 1])) {
bb.resetNumLocals();
int diffL = stackMapDiff(prev.numLocals, prev.localsTypes,
bb.numLocals, bb.localsTypes);
toStackMapBody(writer, bb, diffL, offsetDelta, prev);
offsetDelta = bb.length - 1;
prev = bb;
}
else if (bb.incoming == 0) {
// com.fitburad code.
writer.sameFrame(offsetDelta);
offsetDelta = bb.length - 1;
prev = bb;
}
else
offsetDelta += bb.length;
}
return writer.toStackMapTable(cpool);
}
/**
* Returns true if cur is a branch target.
*/
private boolean isTarget(TypedBlock cur, TypedBlock prev) {
int in = cur.incoming;
if (in > 1)
return true;
else if (in < 1)
return false;
return prev.stop;
}
private void toStackMapBody(StackMapTable.Writer writer, TypedBlock bb,
int diffL, int offsetDelta, TypedBlock prev) {
// if diffL is -100, two TypeData arrays do not share
// any elements.
int stackTop = bb.stackTop;
if (stackTop == 0) {
if (diffL == 0) {
writer.sameFrame(offsetDelta);
return;
}
else if (0 > diffL && diffL >= -3) {
writer.chopFrame(offsetDelta, -diffL);
return;
}
else if (0 < diffL && diffL <= 3) {
int[] data = new int[diffL];
int[] tags = fillStackMap(bb.numLocals - prev.numLocals,
prev.numLocals, data,
bb.localsTypes);
writer.appendFrame(offsetDelta, tags, data);
return;
}
}
else if (stackTop == 1 && diffL == 0) {
TypeData td = bb.stackTypes[0];
writer.sameLocals(offsetDelta, td.getTypeTag(), td.getTypeData(cpool));
return;
}
else if (stackTop == 2 && diffL == 0) {
TypeData td = bb.stackTypes[0];
if (td.is2WordType()) {
// bb.stackTypes[1] must be TOP.
writer.sameLocals(offsetDelta, td.getTypeTag(), td.getTypeData(cpool));
return;
}
}
int[] sdata = new int[stackTop];
int[] stags = fillStackMap(stackTop, 0, sdata, bb.stackTypes);
int[] ldata = new int[bb.numLocals];
int[] ltags = fillStackMap(bb.numLocals, 0, ldata, bb.localsTypes);
writer.fullFrame(offsetDelta, ltags, ldata, stags, sdata);
}
private int[] fillStackMap(int num, int offset, int[] data, TypeData[] types) {
int realNum = diffSize(types, offset, offset + num);
ConstPool cp = cpool;
int[] tags = new int[realNum];
int j = 0;
for (int i = 0; i < num; i++) {
TypeData td = types[offset + i];
tags[j] = td.getTypeTag();
data[j] = td.getTypeData(cp);
if (td.is2WordType())
i++;
j++;
}
return tags;
}
private static int stackMapDiff(int oldTdLen, TypeData[] oldTd,
int newTdLen, TypeData[] newTd)
{
int diff = newTdLen - oldTdLen;
int len;
if (diff > 0)
len = oldTdLen;
else
len = newTdLen;
if (stackMapEq(oldTd, newTd, len))
if (diff > 0)
return diffSize(newTd, len, newTdLen);
else
return -diffSize(oldTd, len, oldTdLen);
else
return -100;
}
private static boolean stackMapEq(TypeData[] oldTd, TypeData[] newTd, int len) {
for (int i = 0; i < len; i++) {
if (!oldTd[i].eq(newTd[i]))
return false;
}
return true;
}
private static int diffSize(TypeData[] types, int offset, int len) {
int num = 0;
while (offset < len) {
TypeData td = types[offset++];
num++;
if (td.is2WordType())
offset++;
}
return num;
}
// Phase 3 for J2ME
public StackMap toStackMap2(ConstPool cp, TypedBlock[] blocks) {
StackMap.Writer writer = new StackMap.Writer();
int n = blocks.length; // should be > 0
boolean[] effective = new boolean[n];
TypedBlock prev = blocks[0];
// Is the first instruction a branch target?
effective[0] = prev.incoming > 0;
int num = effective[0] ? 1 : 0;
for (int i = 1; i < n; i++) {
TypedBlock bb = blocks[i];
if (effective[i] = isTarget(bb, blocks[i - 1])) {
bb.resetNumLocals();
prev = bb;
num++;
}
}
if (num == 0)
return null;
writer.write16bit(num);
for (int i = 0; i < n; i++)
if (effective[i])
writeStackFrame(writer, cp, blocks[i].position, blocks[i]);
return writer.toStackMap(cp);
}
private void writeStackFrame(StackMap.Writer writer, ConstPool cp, int offset, TypedBlock tb) {
writer.write16bit(offset);
writeVerifyTypeInfo(writer, cp, tb.localsTypes, tb.numLocals);
writeVerifyTypeInfo(writer, cp, tb.stackTypes, tb.stackTop);
}
private void writeVerifyTypeInfo(StackMap.Writer writer, ConstPool cp, TypeData[] types, int num) {
int numDWord = 0;
for (int i = 0; i < num; i++) {
TypeData td = types[i];
if (td != null && td.is2WordType()) {
numDWord++;
i++;
}
}
writer.write16bit(num - numDWord);
for (int i = 0; i < num; i++) {
TypeData td = types[i];
writer.writeVerifyTypeInfo(td.getTypeTag(), td.getTypeData(cp));
if (td.is2WordType())
i++;
}
}
}
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