/** Loads the code of the method. */
protected Instruction[] loadCode(Method m) {
Code c = m.getCode();
if (c == null) {
return null;
}
InstructionList il = new InstructionList(c.getCode());
InstructionHandle[] hs = il.getInstructionHandles();
int length = hs.length;
Instruction[] is = new Instruction[length];
for (int i = 0; i < length; i++) {
is[i] = insnFactory.createAndInitialize(this, hs[i], i, m.getConstantPool());
if (c.getLineNumberTable() != null) {
// annoying bug when BCEL don't seem to find linenumber - pos match
// also sometimes linenumber tables are not available
is[i].setContext(
ci.getName(),
name,
c.getLineNumberTable().getSourceLine(is[i].getPosition()),
is[i].getPosition());
}
}
return is;
}
public Instruction createInstructionGetfield(Element inst) throws IllegalXMLVMException {
String classType = inst.getAttributeValue("class-type");
String field = inst.getAttributeValue("field");
String type = inst.getAttributeValue("type");
Type t = parseTypeString(type);
return _factory.createGetField(classType, field, t);
}
/** Marks the code starting at the given offset. */
private void markCode(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset) {
boolean oldNext = next;
byte[] code = codeAttribute.code;
// Continue with the current instruction as long as we haven't marked it
// yet.
while (!isReachable[offset]) {
// Get the current instruction.
Instruction instruction = InstructionFactory.create(code, offset);
// Mark it as reachable.
isReachable[offset] = true;
// By default, we'll assume we can continue with the next
// instruction in a moment.
next = true;
// Mark the branch targets, if any.
instruction.accept(clazz, method, codeAttribute, offset, this);
// Can we really continue with the next instruction?
if (!next) {
break;
}
// Go to the next instruction.
offset += instruction.length(offset);
}
next = oldNext;
}
private Instruction createInvokeInstruction(Element inst, short kind)
throws IllegalXMLVMException {
String classType = inst.getAttributeValue("class-type");
String methodName = inst.getAttributeValue("method");
Element signature = inst.getChild("signature", nsXMLVM);
Type retType = collectReturnType(signature);
Type[] argTypes = collectArgumentTypes(signature);
return _factory.createInvoke(classType, methodName, retType, argTypes, kind);
}
protected MethodInfo createCallStub(String originator, int id) {
MethodInfo mi = new MethodInfo(id);
String cname = ci.getName();
Instruction insn;
mi.name =
originator
+ name; // + cname; // could maybe also include the called method, but keep it fast
mi.signature = "()V";
mi.maxLocals = isStatic() ? 0 : 1;
mi.maxStack = getNumberOfCallerStackSlots(); // <2do> cache for optimization
mi.localVariableNames = EMPTY;
mi.localVariableTypes = EMPTY;
mi.lineNumbers = null;
mi.exceptions = null;
mi.thrownExceptionClassNames = null;
mi.uniqueName = mi.name;
// createAndInitialize the code
CodeBuilder cb = mi.getCodeBuilder();
if (isStatic()) {
mi.modifiers |= Modifier.STATIC;
if (isClinit()) {
insn = insnFactory.create(null, INVOKECLINIT.OPCODE);
} else {
insn = insnFactory.create(null, Constants.INVOKESTATIC);
}
} else if (name.equals("<init>")) {
insn = insnFactory.create(null, Constants.INVOKESPECIAL);
} else {
insn = insnFactory.create(null, Constants.INVOKEVIRTUAL);
}
((InvokeInstruction) insn).setInvokedMethod(cname, name, signature);
cb.append(insn);
insn = insnFactory.create(null, Constants.RETURN);
cb.append(insn);
cb.setCode();
return mi;
}
public void visitExceptionInfo(
Clazz clazz, Method method, CodeAttribute codeAttribute, ExceptionInfo exceptionInfo) {
int startPC = Math.max(exceptionInfo.u2startPC, clipStart);
int endPC = Math.min(exceptionInfo.u2endPC, clipEnd);
int handlerPC = exceptionInfo.u2handlerPC;
int catchType = exceptionInfo.u2catchType;
// Exclude any subroutine invocations that jump out of the try block,
// by adding a try block before (and later on, after) each invocation.
for (int offset = startPC; offset < endPC; offset++) {
if (branchTargetFinder.isSubroutineInvocation(offset)) {
Instruction instruction = InstructionFactory.create(codeAttribute.code, offset);
int instructionLength = instruction.length(offset);
// Is it a subroutine invocation?
if (!exceptionInfo.isApplicable(offset + ((BranchInstruction) instruction).branchOffset)) {
if (DEBUG) {
System.out.println(
" Appending extra exception [" + startPC + " -> " + offset + "] -> " + handlerPC);
}
// Append a try block that ends before the subroutine invocation.
codeAttributeComposer.appendException(
new ExceptionInfo(startPC, offset, handlerPC, catchType));
// The next try block will start after the subroutine invocation.
startPC = offset + instructionLength;
}
}
}
if (DEBUG) {
System.out.println(
" Appending exception [" + startPC + " -> " + endPC + "] -> " + handlerPC);
}
// Append the exception. Note that exceptions with empty try blocks
// are automatically ignored.
codeAttributeComposer.appendException(new ExceptionInfo(startPC, endPC, handlerPC, catchType));
}
public void visitBranchInstruction(
Clazz clazz,
Method method,
CodeAttribute codeAttribute,
int offset,
BranchInstruction branchInstruction) {
// Check if the instruction is an unconditional goto instruction.
byte opcode = branchInstruction.opcode;
if (opcode == InstructionConstants.OP_GOTO || opcode == InstructionConstants.OP_GOTO_W) {
// Check if the goto instruction points to another simple goto
// instruction.
int branchOffset = branchInstruction.branchOffset;
int targetOffset = offset + branchOffset;
if (branchOffset != branchInstruction.length(offset)
&& !codeAttributeEditor.isModified(offset)
&& !codeAttributeEditor.isModified(targetOffset)) {
Instruction targetInstruction = InstructionFactory.create(codeAttribute.code, targetOffset);
if (targetInstruction.opcode == InstructionConstants.OP_GOTO) {
// Simplify the goto instruction.
int targetBranchOffset = ((BranchInstruction) targetInstruction).branchOffset;
Instruction newBranchInstruction =
new BranchInstruction(opcode, (branchOffset + targetBranchOffset));
codeAttributeEditor.replaceInstruction(offset, newBranchInstruction);
// Visit the instruction, if required.
if (extraInstructionVisitor != null) {
extraInstructionVisitor.visitBranchInstruction(
clazz, method, codeAttribute, offset, branchInstruction);
}
}
}
}
}
public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute) {
// DEBUG =
// clazz.getName().equals("abc/Def") &&
// method.getName(clazz).equals("abc");
if (DEBUG) {
method.accept(clazz, new ClassPrinter());
}
branchTargetFinder.visitCodeAttribute(clazz, method, codeAttribute);
// Don't bother if there aren't any subroutines anyway.
if (!containsSubroutines(codeAttribute)) {
return;
}
if (DEBUG) {
System.out.println(
"SubroutineInliner: processing ["
+ clazz.getName()
+ "."
+ method.getName(clazz)
+ method.getDescriptor(clazz)
+ "]");
}
// Append the body of the code.
codeAttributeComposer.reset();
codeAttributeComposer.beginCodeFragment(codeAttribute.u4codeLength);
// Copy the non-subroutine instructions.
int offset = 0;
while (offset < codeAttribute.u4codeLength) {
Instruction instruction = InstructionFactory.create(codeAttribute.code, offset);
int instructionLength = instruction.length(offset);
// Is this returning subroutine?
if (branchTargetFinder.isSubroutine(offset)
&& branchTargetFinder.isSubroutineReturning(offset)) {
// Skip the subroutine.
if (DEBUG) {
System.out.println(
" Skipping original subroutine instruction " + instruction.toString(offset));
}
// Append a label at this offset instead.
codeAttributeComposer.appendLabel(offset);
} else {
// Copy the instruction, inlining any subroutine call recursively.
instruction.accept(clazz, method, codeAttribute, offset, this);
}
offset += instructionLength;
}
// Copy the exceptions. Note that exceptions with empty try blocks
// are automatically removed.
codeAttribute.exceptionsAccept(clazz, method, subroutineExceptionInliner);
if (DEBUG) {
System.out.println(" Appending label after code at [" + offset + "]");
}
// Append a label just after the code.
codeAttributeComposer.appendLabel(codeAttribute.u4codeLength);
// End and update the code attribute.
codeAttributeComposer.endCodeFragment();
codeAttributeComposer.visitCodeAttribute(clazz, method, codeAttribute);
if (DEBUG) {
method.accept(clazz, new ClassPrinter());
}
}
public Instruction createInstructionNew(Element inst) {
String t = inst.getAttributeValue("type");
return _factory.createNew(t);
}
public Instruction createInstructionAload(Element inst) throws IllegalXMLVMException {
String t = inst.getAttributeValue("type");
Type type = parseTypeString(t);
int idx = Integer.parseInt(inst.getAttributeValue("index"));
return _factory.createLoad(type, idx);
}
public Instruction createInstructionLreturn(Element inst) {
return _factory.createReturn(Type.LONG);
}
public Instruction createInstructionFreturn(Element inst) {
return _factory.createReturn(Type.FLOAT);
}
public Instruction createInstructionDreturn(Element inst) {
return _factory.createReturn(Type.DOUBLE);
}
public Instruction createInstructionIreturn(Element inst) {
return _factory.createReturn(Type.INT);
}
public Instruction createInstructionReturn(Element inst) {
return _factory.createReturn(Type.VOID);
}
/**
* Evaluates a block of instructions that hasn't been handled before, starting at the given offset
* and ending at a branch instruction, a return instruction, or a throw instruction. Branch
* instructions are handled recursively.
*/
private void evaluateInstructionBlock(
Clazz clazz, Method method, CodeAttribute codeAttribute, int instructionOffset) {
if (DEBUG) {
if (evaluated[instructionOffset]) {
System.out.println("-- (instruction block at " + instructionOffset + " already evaluated)");
} else {
System.out.println("-- instruction block:");
}
}
// Remember the initial stack size.
int initialStackSize = stackSize;
// Remember the maximum stack size.
if (maxStackSize < stackSize) {
maxStackSize = stackSize;
}
// Evaluate any instructions that haven't been evaluated before.
while (!evaluated[instructionOffset]) {
// Mark the instruction as evaluated.
evaluated[instructionOffset] = true;
Instruction instruction = InstructionFactory.create(codeAttribute.code, instructionOffset);
if (DEBUG) {
int stackPushCount = instruction.stackPushCount(clazz);
int stackPopCount = instruction.stackPopCount(clazz);
System.out.println(
"["
+ instructionOffset
+ "]: "
+ stackSize
+ " - "
+ stackPopCount
+ " + "
+ stackPushCount
+ " = "
+ (stackSize + stackPushCount - stackPopCount)
+ ": "
+ instruction.toString(instructionOffset));
}
// Compute the instruction's effect on the stack size.
stackSize -= instruction.stackPopCount(clazz);
if (stackSize < 0) {
throw new IllegalArgumentException(
"Stack size becomes negative after instruction "
+ instruction.toString(instructionOffset)
+ " in ["
+ clazz.getName()
+ "."
+ method.getName(clazz)
+ method.getDescriptor(clazz)
+ "]");
}
stackSizes[instructionOffset] = stackSize += instruction.stackPushCount(clazz);
// Remember the maximum stack size.
if (maxStackSize < stackSize) {
maxStackSize = stackSize;
}
// Remember the next instruction offset.
int nextInstructionOffset = instructionOffset + instruction.length(instructionOffset);
// Visit the instruction, in order to handle branches.
instruction.accept(clazz, method, codeAttribute, instructionOffset, this);
// Stop evaluating after a branch.
if (exitInstructionBlock) {
break;
}
// Continue with the next instruction.
instructionOffset = nextInstructionOffset;
if (DEBUG) {
if (evaluated[instructionOffset]) {
System.out.println("-- (instruction at " + instructionOffset + " already evaluated)");
}
}
}
// Restore the stack size for possible subsequent instruction blocks.
this.stackSize = initialStackSize;
}
public Instruction createInstructionGetstatic(Element inst) throws IllegalXMLVMException {
String classType = inst.getAttributeValue("class-type");
String field = inst.getAttributeValue("field");
Type type = parseTypeString(inst.getAttributeValue("type"));
return _factory.createFieldAccess(classType, field, type, Constants.GETSTATIC);
}
