use of org.apache.tapestry5.internal.plastic.asm.tree.LookupSwitchInsnNode in project tapestry-5 by apache.
the class Analyzer method findSubroutine.
/**
* Follows the control flow graph of the currently analyzed method, starting at the given
* instruction index, and stores a copy of the given subroutine in {@link #subroutines} for each
* encountered instruction. Jumps to nested subroutines are <i>not</i> followed: instead, the
* corresponding instructions are put in the given list.
*
* @param insnIndex an instruction index.
* @param subroutine a subroutine.
* @param jsrInsns where the jsr instructions for nested subroutines must be put.
* @throws AnalyzerException if the control flow graph can fall off the end of the code.
*/
private void findSubroutine(final int insnIndex, final Subroutine subroutine, final List<AbstractInsnNode> jsrInsns) throws AnalyzerException {
ArrayList<Integer> instructionIndicesToProcess = new ArrayList<>();
instructionIndicesToProcess.add(insnIndex);
while (!instructionIndicesToProcess.isEmpty()) {
int currentInsnIndex = instructionIndicesToProcess.remove(instructionIndicesToProcess.size() - 1);
if (currentInsnIndex < 0 || currentInsnIndex >= insnListSize) {
throw new AnalyzerException(null, "Execution can fall off the end of the code");
}
if (subroutines[currentInsnIndex] != null) {
continue;
}
subroutines[currentInsnIndex] = new Subroutine(subroutine);
AbstractInsnNode currentInsn = insnList.get(currentInsnIndex);
// Push the normal successors of currentInsn onto instructionIndicesToProcess.
if (currentInsn instanceof JumpInsnNode) {
if (currentInsn.getOpcode() == JSR) {
// Do not follow a jsr, it leads to another subroutine!
jsrInsns.add(currentInsn);
} else {
JumpInsnNode jumpInsn = (JumpInsnNode) currentInsn;
instructionIndicesToProcess.add(insnList.indexOf(jumpInsn.label));
}
} else if (currentInsn instanceof TableSwitchInsnNode) {
TableSwitchInsnNode tableSwitchInsn = (TableSwitchInsnNode) currentInsn;
findSubroutine(insnList.indexOf(tableSwitchInsn.dflt), subroutine, jsrInsns);
for (int i = tableSwitchInsn.labels.size() - 1; i >= 0; --i) {
LabelNode labelNode = tableSwitchInsn.labels.get(i);
instructionIndicesToProcess.add(insnList.indexOf(labelNode));
}
} else if (currentInsn instanceof LookupSwitchInsnNode) {
LookupSwitchInsnNode lookupSwitchInsn = (LookupSwitchInsnNode) currentInsn;
findSubroutine(insnList.indexOf(lookupSwitchInsn.dflt), subroutine, jsrInsns);
for (int i = lookupSwitchInsn.labels.size() - 1; i >= 0; --i) {
LabelNode labelNode = lookupSwitchInsn.labels.get(i);
instructionIndicesToProcess.add(insnList.indexOf(labelNode));
}
}
// Push the exception handler successors of currentInsn onto instructionIndicesToProcess.
List<TryCatchBlockNode> insnHandlers = handlers[currentInsnIndex];
if (insnHandlers != null) {
for (TryCatchBlockNode tryCatchBlock : insnHandlers) {
instructionIndicesToProcess.add(insnList.indexOf(tryCatchBlock.handler));
}
}
// Push the next instruction, if the control flow can go from currentInsn to the next.
switch(currentInsn.getOpcode()) {
case GOTO:
case RET:
case TABLESWITCH:
case LOOKUPSWITCH:
case IRETURN:
case LRETURN:
case FRETURN:
case DRETURN:
case ARETURN:
case RETURN:
case ATHROW:
break;
default:
instructionIndicesToProcess.add(currentInsnIndex + 1);
break;
}
}
}
use of org.apache.tapestry5.internal.plastic.asm.tree.LookupSwitchInsnNode in project tapestry-5 by apache.
the class JSRInlinerAdapter method findReachableInsns.
/**
* Finds the instructions that are reachable from the given instruction, without following any JSR
* instruction nor any exception handler. For this the control flow graph is visited with a depth
* first search.
*
* @param insnIndex the index of an instruction of the subroutine.
* @param subroutineInsns where the indices of the instructions of the subroutine must be stored.
* @param visitedInsns the indices of the instructions that have been visited so far (including in
* previous calls to this method). This bitset is updated by this method each time a new
* instruction is visited. It is used to make sure each instruction is visited at most once.
*/
private void findReachableInsns(final int insnIndex, final BitSet subroutineInsns, final BitSet visitedInsns) {
int currentInsnIndex = insnIndex;
// return or not from a JSR, but this is more complicated).
while (currentInsnIndex < instructions.size()) {
// Visit each instruction at most once.
if (subroutineInsns.get(currentInsnIndex)) {
return;
}
subroutineInsns.set(currentInsnIndex);
// Check if this instruction has already been visited by another subroutine.
if (visitedInsns.get(currentInsnIndex)) {
sharedSubroutineInsns.set(currentInsnIndex);
}
visitedInsns.set(currentInsnIndex);
AbstractInsnNode currentInsnNode = instructions.get(currentInsnIndex);
if (currentInsnNode.getType() == AbstractInsnNode.JUMP_INSN && currentInsnNode.getOpcode() != JSR) {
// Don't follow JSR instructions in the control flow graph.
JumpInsnNode jumpInsnNode = (JumpInsnNode) currentInsnNode;
findReachableInsns(instructions.indexOf(jumpInsnNode.label), subroutineInsns, visitedInsns);
} else if (currentInsnNode.getType() == AbstractInsnNode.TABLESWITCH_INSN) {
TableSwitchInsnNode tableSwitchInsnNode = (TableSwitchInsnNode) currentInsnNode;
findReachableInsns(instructions.indexOf(tableSwitchInsnNode.dflt), subroutineInsns, visitedInsns);
for (LabelNode labelNode : tableSwitchInsnNode.labels) {
findReachableInsns(instructions.indexOf(labelNode), subroutineInsns, visitedInsns);
}
} else if (currentInsnNode.getType() == AbstractInsnNode.LOOKUPSWITCH_INSN) {
LookupSwitchInsnNode lookupSwitchInsnNode = (LookupSwitchInsnNode) currentInsnNode;
findReachableInsns(instructions.indexOf(lookupSwitchInsnNode.dflt), subroutineInsns, visitedInsns);
for (LabelNode labelNode : lookupSwitchInsnNode.labels) {
findReachableInsns(instructions.indexOf(labelNode), subroutineInsns, visitedInsns);
}
}
// Check if this instruction falls through to the next instruction; if not, return.
switch(instructions.get(currentInsnIndex).getOpcode()) {
case GOTO:
case RET:
case TABLESWITCH:
case LOOKUPSWITCH:
case IRETURN:
case LRETURN:
case FRETURN:
case DRETURN:
case ARETURN:
case RETURN:
case ATHROW:
// Note: this either returns from this subroutine, or from a parent subroutine.
return;
default:
// Go to the next instruction.
currentInsnIndex++;
break;
}
}
}
use of org.apache.tapestry5.internal.plastic.asm.tree.LookupSwitchInsnNode in project tapestry-5 by apache.
the class Analyzer method analyze.
/**
* Analyzes the given method.
*
* @param owner the internal name of the class to which 'method' belongs.
* @param method the method to be analyzed. The maxStack and maxLocals fields must have correct
* values.
* @return the symbolic state of the execution stack frame at each bytecode instruction of the
* method. The size of the returned array is equal to the number of instructions (and labels)
* of the method. A given frame is {@literal null} if and only if the corresponding
* instruction cannot be reached (dead code).
* @throws AnalyzerException if a problem occurs during the analysis.
*/
@SuppressWarnings("unchecked")
public Frame<V>[] analyze(final String owner, final MethodNode method) throws AnalyzerException {
if ((method.access & (ACC_ABSTRACT | ACC_NATIVE)) != 0) {
frames = (Frame<V>[]) new Frame<?>[0];
return frames;
}
insnList = method.instructions;
insnListSize = insnList.size();
handlers = (List<TryCatchBlockNode>[]) new List<?>[insnListSize];
frames = (Frame<V>[]) new Frame<?>[insnListSize];
subroutines = new Subroutine[insnListSize];
inInstructionsToProcess = new boolean[insnListSize];
instructionsToProcess = new int[insnListSize];
numInstructionsToProcess = 0;
// fact that execution can flow from this instruction to the exception handler.
for (int i = 0; i < method.tryCatchBlocks.size(); ++i) {
TryCatchBlockNode tryCatchBlock = method.tryCatchBlocks.get(i);
int startIndex = insnList.indexOf(tryCatchBlock.start);
int endIndex = insnList.indexOf(tryCatchBlock.end);
for (int j = startIndex; j < endIndex; ++j) {
List<TryCatchBlockNode> insnHandlers = handlers[j];
if (insnHandlers == null) {
insnHandlers = new ArrayList<>();
handlers[j] = insnHandlers;
}
insnHandlers.add(tryCatchBlock);
}
}
// For each instruction, compute the subroutine to which it belongs.
// Follow the main 'subroutine', and collect the jsr instructions to nested subroutines.
Subroutine main = new Subroutine(null, method.maxLocals, null);
List<AbstractInsnNode> jsrInsns = new ArrayList<>();
findSubroutine(0, main, jsrInsns);
// Follow the nested subroutines, and collect their own nested subroutines, until all
// subroutines are found.
Map<LabelNode, Subroutine> jsrSubroutines = new HashMap<>();
while (!jsrInsns.isEmpty()) {
JumpInsnNode jsrInsn = (JumpInsnNode) jsrInsns.remove(0);
Subroutine subroutine = jsrSubroutines.get(jsrInsn.label);
if (subroutine == null) {
subroutine = new Subroutine(jsrInsn.label, method.maxLocals, jsrInsn);
jsrSubroutines.put(jsrInsn.label, subroutine);
findSubroutine(insnList.indexOf(jsrInsn.label), subroutine, jsrInsns);
} else {
subroutine.callers.add(jsrInsn);
}
}
// intermediate step above to find the real ones).
for (int i = 0; i < insnListSize; ++i) {
if (subroutines[i] != null && subroutines[i].start == null) {
subroutines[i] = null;
}
}
// Initializes the data structures for the control flow analysis.
Frame<V> currentFrame = computeInitialFrame(owner, method);
merge(0, currentFrame, null);
init(owner, method);
// Control flow analysis.
while (numInstructionsToProcess > 0) {
// Get and remove one instruction from the list of instructions to process.
int insnIndex = instructionsToProcess[--numInstructionsToProcess];
Frame<V> oldFrame = frames[insnIndex];
Subroutine subroutine = subroutines[insnIndex];
inInstructionsToProcess[insnIndex] = false;
// Simulate the execution of this instruction.
AbstractInsnNode insnNode = null;
try {
insnNode = method.instructions.get(insnIndex);
int insnOpcode = insnNode.getOpcode();
int insnType = insnNode.getType();
if (insnType == AbstractInsnNode.LABEL || insnType == AbstractInsnNode.LINE || insnType == AbstractInsnNode.FRAME) {
merge(insnIndex + 1, oldFrame, subroutine);
newControlFlowEdge(insnIndex, insnIndex + 1);
} else {
currentFrame.init(oldFrame).execute(insnNode, interpreter);
subroutine = subroutine == null ? null : new Subroutine(subroutine);
if (insnNode instanceof JumpInsnNode) {
JumpInsnNode jumpInsn = (JumpInsnNode) insnNode;
if (insnOpcode != GOTO && insnOpcode != JSR) {
currentFrame.initJumpTarget(insnOpcode, /* target = */
null);
merge(insnIndex + 1, currentFrame, subroutine);
newControlFlowEdge(insnIndex, insnIndex + 1);
}
int jumpInsnIndex = insnList.indexOf(jumpInsn.label);
currentFrame.initJumpTarget(insnOpcode, jumpInsn.label);
if (insnOpcode == JSR) {
merge(jumpInsnIndex, currentFrame, new Subroutine(jumpInsn.label, method.maxLocals, jumpInsn));
} else {
merge(jumpInsnIndex, currentFrame, subroutine);
}
newControlFlowEdge(insnIndex, jumpInsnIndex);
} else if (insnNode instanceof LookupSwitchInsnNode) {
LookupSwitchInsnNode lookupSwitchInsn = (LookupSwitchInsnNode) insnNode;
int targetInsnIndex = insnList.indexOf(lookupSwitchInsn.dflt);
currentFrame.initJumpTarget(insnOpcode, lookupSwitchInsn.dflt);
merge(targetInsnIndex, currentFrame, subroutine);
newControlFlowEdge(insnIndex, targetInsnIndex);
for (int i = 0; i < lookupSwitchInsn.labels.size(); ++i) {
LabelNode label = lookupSwitchInsn.labels.get(i);
targetInsnIndex = insnList.indexOf(label);
currentFrame.initJumpTarget(insnOpcode, label);
merge(targetInsnIndex, currentFrame, subroutine);
newControlFlowEdge(insnIndex, targetInsnIndex);
}
} else if (insnNode instanceof TableSwitchInsnNode) {
TableSwitchInsnNode tableSwitchInsn = (TableSwitchInsnNode) insnNode;
int targetInsnIndex = insnList.indexOf(tableSwitchInsn.dflt);
currentFrame.initJumpTarget(insnOpcode, tableSwitchInsn.dflt);
merge(targetInsnIndex, currentFrame, subroutine);
newControlFlowEdge(insnIndex, targetInsnIndex);
for (int i = 0; i < tableSwitchInsn.labels.size(); ++i) {
LabelNode label = tableSwitchInsn.labels.get(i);
currentFrame.initJumpTarget(insnOpcode, label);
targetInsnIndex = insnList.indexOf(label);
merge(targetInsnIndex, currentFrame, subroutine);
newControlFlowEdge(insnIndex, targetInsnIndex);
}
} else if (insnOpcode == RET) {
if (subroutine == null) {
throw new AnalyzerException(insnNode, "RET instruction outside of a subroutine");
}
for (int i = 0; i < subroutine.callers.size(); ++i) {
JumpInsnNode caller = subroutine.callers.get(i);
int jsrInsnIndex = insnList.indexOf(caller);
if (frames[jsrInsnIndex] != null) {
merge(jsrInsnIndex + 1, frames[jsrInsnIndex], currentFrame, subroutines[jsrInsnIndex], subroutine.localsUsed);
newControlFlowEdge(insnIndex, jsrInsnIndex + 1);
}
}
} else if (insnOpcode != ATHROW && (insnOpcode < IRETURN || insnOpcode > RETURN)) {
if (subroutine != null) {
if (insnNode instanceof VarInsnNode) {
int var = ((VarInsnNode) insnNode).var;
subroutine.localsUsed[var] = true;
if (insnOpcode == LLOAD || insnOpcode == DLOAD || insnOpcode == LSTORE || insnOpcode == DSTORE) {
subroutine.localsUsed[var + 1] = true;
}
} else if (insnNode instanceof IincInsnNode) {
int var = ((IincInsnNode) insnNode).var;
subroutine.localsUsed[var] = true;
}
}
merge(insnIndex + 1, currentFrame, subroutine);
newControlFlowEdge(insnIndex, insnIndex + 1);
}
}
List<TryCatchBlockNode> insnHandlers = handlers[insnIndex];
if (insnHandlers != null) {
for (TryCatchBlockNode tryCatchBlock : insnHandlers) {
Type catchType;
if (tryCatchBlock.type == null) {
catchType = Type.getObjectType("java/lang/Throwable");
} else {
catchType = Type.getObjectType(tryCatchBlock.type);
}
if (newControlFlowExceptionEdge(insnIndex, tryCatchBlock)) {
Frame<V> handler = newFrame(oldFrame);
handler.clearStack();
handler.push(interpreter.newExceptionValue(tryCatchBlock, handler, catchType));
merge(insnList.indexOf(tryCatchBlock.handler), handler, subroutine);
}
}
}
} catch (AnalyzerException e) {
throw new AnalyzerException(e.node, "Error at instruction " + insnIndex + ": " + e.getMessage(), e);
} catch (RuntimeException e) {
// DontCheck(IllegalCatch): can't be fixed, for backward compatibility.
throw new AnalyzerException(insnNode, "Error at instruction " + insnIndex + ": " + e.getMessage(), e);
}
}
return frames;
}
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