/**
* implements the visitor to look for methods that return a constant
*
* @param seen the opcode of the currently parsed instruction
*/
@Override
public void sawOpcode(int seen) {
boolean sawSBToString = false;
try {
if (!methodSuspect) {
return;
}
stack.precomputation(this);
if ((seen >= IRETURN) && (seen <= ARETURN)) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
int register = item.getRegisterNumber();
if (registerConstants.containsKey(register)
&& (registerConstants.get(register) == null)) {
methodSuspect = false;
return;
}
Object constant = item.getConstant();
if (constant == null) {
methodSuspect = false;
return;
}
if (Boolean.TRUE.equals(item.getUserValue()) && ("".equals(constant))) {
methodSuspect = false;
return;
}
if ((returnConstant != null) && (!returnConstant.equals(constant))) {
methodSuspect = false;
return;
}
returnRegister = item.getRegisterNumber();
returnConstant = constant;
}
} else if ((seen == GOTO) || (seen == GOTO_W)) {
if (stack.getStackDepth() > 0) {
methodSuspect =
false; // Trinaries confuse us too much, if the code has a ternary well - oh well
}
} else if (seen == INVOKEVIRTUAL) {
String clsName = getClassConstantOperand();
if (clsName.startsWith("java/lang/StringB")) {
sawSBToString = "toString".equals(getNameConstantOperand());
}
} else if ((seen >= ISTORE) && (seen <= ASTORE_3) || (seen == IINC)) {
int register = getRegisterOperand();
if ((returnRegister != -1) && (register == returnRegister)) {
methodSuspect = false;
}
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
Object constant = item.getConstant();
if (registerConstants.containsKey(register)) {
if ((constant == null) || !constant.equals(registerConstants.get(register))) {
registerConstants.put(register, null);
}
} else {
registerConstants.put(register, constant);
}
} else {
registerConstants.put(register, null);
}
if (returnRegister == register) {
Object constant = registerConstants.get(returnRegister);
if (constant != null) {
methodSuspect = false;
}
}
}
} finally {
TernaryPatcher.pre(stack, seen);
stack.sawOpcode(this, seen);
TernaryPatcher.post(stack, seen);
if (sawSBToString && (stack.getStackDepth() > 0)) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(Boolean.TRUE);
}
}
}
/**
* implements the visitor to find stores to locals of synchronized collections
*
* @param seen the opcode of the currently parsed instruction
*/
@Override
public void sawOpcode(int seen) {
Integer tosIsSyncColReg = null;
try {
stack.mergeJumps(this);
if (seen == INVOKESPECIAL) {
if ("<init>".equals(getNameConstantOperand())) {
Integer minVersion = syncCtors.get(getClassConstantOperand());
if ((minVersion != null) && (classVersion >= minVersion.intValue())) {
tosIsSyncColReg = Integer.valueOf(-1);
}
}
} else if (seen == INVOKESTATIC) {
if ("java/util/Collections".equals(getClassConstantOperand())) {
if (syncMethods.contains(getNameConstantOperand())) {
tosIsSyncColReg = Integer.valueOf(-1);
}
}
} else if ((seen == ASTORE) || ((seen >= ASTORE_0) && (seen <= ASTORE_3))) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
int reg = RegisterUtils.getAStoreReg(this, seen);
if (item.getUserValue() != null) {
if (!syncRegs.containsKey(Integer.valueOf(reg))) {
CollectionRegInfo cri =
new CollectionRegInfo(
SourceLineAnnotation.fromVisitedInstruction(this),
RegisterUtils.getLocalVariableEndRange(
getMethod().getLocalVariableTable(), reg, getNextPC()));
syncRegs.put(Integer.valueOf(reg), cri);
}
} else {
CollectionRegInfo cri = syncRegs.get(Integer.valueOf(reg));
if (cri == null) {
cri =
new CollectionRegInfo(
RegisterUtils.getLocalVariableEndRange(
getMethod().getLocalVariableTable(), reg, getNextPC()));
syncRegs.put(Integer.valueOf(reg), cri);
}
cri.setIgnore();
}
}
} else if ((seen == ALOAD) || ((seen >= ALOAD_0) && (seen <= ALOAD_3))) {
int reg = RegisterUtils.getALoadReg(this, seen);
CollectionRegInfo cri = syncRegs.get(Integer.valueOf(reg));
if ((cri != null) && !cri.getIgnore()) tosIsSyncColReg = Integer.valueOf(reg);
} else if ((seen == PUTFIELD) || (seen == ARETURN)) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
syncRegs.remove(item.getUserValue());
}
}
if (syncRegs.size() > 0) {
if ((seen == INVOKESPECIAL)
|| (seen == INVOKEINTERFACE)
|| (seen == INVOKEVIRTUAL)
|| (seen == INVOKESTATIC)) {
String sig = getSigConstantOperand();
int argCount = Type.getArgumentTypes(sig).length;
if (stack.getStackDepth() >= argCount) {
for (int i = 0; i < argCount; i++) {
OpcodeStack.Item item = stack.getStackItem(i);
CollectionRegInfo cri = syncRegs.get(item.getUserValue());
if (cri != null) cri.setPriority(LOW_PRIORITY);
}
}
} else if (seen == MONITORENTER) {
// Assume if synchronized blocks are used then something tricky is going on.
// There is really no valid reason for this, other than folks who use
// synchronized blocks tend to know what's going on.
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
syncRegs.remove(item.getUserValue());
}
} else if (seen == AASTORE) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
syncRegs.remove(item.getUserValue());
}
}
}
int curPC = getPC();
Iterator<CollectionRegInfo> it = syncRegs.values().iterator();
while (it.hasNext()) {
CollectionRegInfo cri = it.next();
if (cri.getEndPCRange() < curPC) {
if (!cri.getIgnore()) {
bugReporter.reportBug(
new BugInstance(this, "LSYC_LOCAL_SYNCHRONIZED_COLLECTION", cri.getPriority())
.addClass(this)
.addMethod(this)
.addSourceLine(cri.getSourceLineAnnotation()));
}
it.remove();
}
}
} finally {
TernaryPatcher.pre(stack, seen);
stack.sawOpcode(this, seen);
TernaryPatcher.post(stack, seen);
if (tosIsSyncColReg != null) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(tosIsSyncColReg);
}
}
}
}
/**
* overrides the visitor to look for uses of collections where the only access to to the
* collection is to write to it
*
* @param seen the opcode of the currently visited instruction
*/
@edu.umd.cs.findbugs.annotations.SuppressFBWarnings(
value = "SF_SWITCH_FALLTHROUGH",
justification = "This fall-through is deliberate and documented")
@Override
public void sawOpcode(int seen) {
Object userObject = null;
// saving and restoring the userobject of the top item, works around a
// bug in Findbugs proper
if (stack.getStackDepth() > 0) {
userObject = stack.getStackItem(0).getUserValue();
}
stack.precomputation(this);
if (stack.getStackDepth() > 0) {
stack.getStackItem(0).setUserValue(userObject);
userObject = null;
}
try {
switch (seen) {
case INVOKESPECIAL:
userObject = sawInvokeSpecial(userObject);
break;
case INVOKEINTERFACE:
case INVOKEVIRTUAL:
sawInvokeInterfaceVirtual();
break;
case INVOKESTATIC:
userObject = sawInvokeStatic(userObject);
// $FALL-THROUGH$
case INVOKEDYNAMIC:
processMethodParms();
break;
case ARETURN:
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
clearUserValue(item);
}
break;
case ASTORE_0:
case ASTORE_1:
case ASTORE_2:
case ASTORE_3:
case ASTORE:
sawAStore(seen);
break;
case ALOAD_0:
case ALOAD_1:
case ALOAD_2:
case ALOAD_3:
case ALOAD:
userObject = sawLoad(seen, userObject);
break;
case AASTORE:
if (stack.getStackDepth() >= 3) {
OpcodeStack.Item item = stack.getStackItem(0);
clearUserValue(item);
}
break;
case PUTFIELD:
sawPutField();
break;
case GETFIELD:
userObject = sawGetField(userObject);
break;
case PUTSTATIC:
sawPutStatic();
break;
case GETSTATIC:
userObject = sawGetStatic(userObject);
break;
case GOTO:
case IFNULL:
case IFNONNULL:
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
Object uo = item.getUserValue();
if ((uo != null) && !(uo instanceof Boolean)) {
clearUserValue(item);
}
sawTernary = true;
}
break;
default:
break;
}
} finally {
TernaryPatcher.pre(stack, seen);
stack.sawOpcode(this, seen);
TernaryPatcher.post(stack, seen);
if ((userObject != null) && (stack.getStackDepth() > 0)) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(userObject);
}
if (sawTernary) {
handleTernary(seen);
}
}
}
@Override
public void sawOpcode(int seen) {
try {
stack.precomputation(this);
int pc = getPC();
if ((loopEnd != -1) && (pc > loopEnd)) {
loopStart = -1;
loopEnd = -1;
regValueType.clear();
}
if ((seen == ALOAD) || ((seen >= ALOAD_0) && (seen <= ALOAD_3))) {
int reg = RegisterUtils.getALoadReg(this, seen);
State type = regValueType.get(Integer.valueOf(reg));
if (type != null) state = type;
else state = State.SEEN_NOTHING;
return;
}
if ((seen == ASTORE) || ((seen >= ASTORE_0) && (seen <= ASTORE_3))) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
int reg = RegisterUtils.getAStoreReg(this, seen);
regValueType.put(Integer.valueOf(reg), (State) item.getUserValue());
}
state = State.SEEN_NOTHING;
return;
}
if ((seen == ILOAD) || ((seen >= ILOAD_0) && (seen <= ILOAD_3))) {
int reg = RegisterUtils.getLoadReg(this, seen);
State type = regValueType.get(Integer.valueOf(reg));
if (type != null) state = type;
else state = State.SEEN_NOTHING;
return;
}
if ((seen == ISTORE) || ((seen >= ISTORE_0) && (seen <= ISTORE_3))) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
int reg = RegisterUtils.getStoreReg(this, seen);
regValueType.put(Integer.valueOf(reg), (State) item.getUserValue());
}
state = State.SEEN_NOTHING;
return;
}
switch (state) {
case SEEN_NOTHING:
if (seen == INVOKESPECIAL) {
if (("java/util/StringTokenizer".equals(getClassConstantOperand()))
&& (Values.CONSTRUCTOR.equals(getNameConstantOperand()))
&& ("(Ljava/lang/String;Ljava/lang/String;)V".equals(getSigConstantOperand())))
state = State.SEEN_STRINGTOKENIZER;
}
break;
case SEEN_STRINGTOKENIZER:
if (seen == INVOKEVIRTUAL) {
String methodName = getNameConstantOperand();
String signature = getSigConstantOperand();
if (("countTokens".equals(methodName)) && ("()I".equals(signature)))
state = State.SEEN_COUNTTOKENS;
else if ("hasMoreTokens".equals(methodName) || "hasMoreElements".equals(methodName))
state = State.SEEN_HASMORE;
else if ("nextToken".equals(methodName) || "nextElement".equals(methodName)) {
if ((pc < loopStart) || (pc > loopEnd)) regValueType.clear();
else state = State.SEEN_NEXT;
}
}
break;
case SEEN_COUNTTOKENS:
if (seen == ANEWARRAY) state = State.SEEN_NEWARRAY;
else if (seen == IF_ICMPGE) {
int target = getBranchTarget() - 3; // sizeof goto
byte[] code = getCode().getCode();
if ((code[target] & 0x000000FF) == GOTO) {
int offset = (code[target + 1] << 1) + code[target + 2];
int gotoTarget = target + offset + 3;
if (gotoTarget < getPC()) {
loopStart = gotoTarget;
loopEnd = target;
}
}
}
break;
case SEEN_HASMORE:
if (seen == IFEQ) {
int target = getBranchTarget() - 3; // sizeof goto
byte[] code = getCode().getCode();
if ((code[target] & 0x000000FF) == GOTO) {
int offset = (code[target + 1] << 1) + code[target + 2];
int gotoTarget = target + offset + 3;
if (gotoTarget < getPC()) {
loopStart = gotoTarget;
loopEnd = target;
}
}
}
state = State.SEEN_NOTHING;
break;
case SEEN_NEXT:
if (seen == AASTORE) {
if ((pc > loopStart) && (pc < loopEnd)) {
if (stack.getStackDepth() > 2) {
OpcodeStack.Item arrayItem = stack.getStackItem(2);
State arrayType = (State) arrayItem.getUserValue();
OpcodeStack.Item elemItem = stack.getStackItem(0);
State elemType = (State) elemItem.getUserValue();
if ((arrayType == State.SEEN_NEWARRAY) && (elemType == State.SEEN_NEXT)) {
bugReporter.reportBug(
new BugInstance(this, BugType.USS_USE_STRING_SPLIT.name(), NORMAL_PRIORITY)
.addClass(this)
.addMethod(this)
.addSourceLine(this));
}
}
}
}
state = State.SEEN_NOTHING;
break;
case SEEN_ARRAYSTORE:
case SEEN_NEWARRAY:
break;
}
} finally {
TernaryPatcher.pre(stack, seen);
stack.sawOpcode(this, seen);
TernaryPatcher.post(stack, seen);
if (state != State.SEEN_NOTHING) {
if (stack.getStackDepth() > 0) {
OpcodeStack.Item item = stack.getStackItem(0);
item.setUserValue(state);
}
}
}
}
