Examples with VarInsnNode org.apache.tapestry5.internal.plastic.asm.tree.VarInsnNode used on opensource projects

Example 1 with VarInsnNode

use of org.apache.tapestry5.internal.plastic.asm.tree.VarInsnNode in project tapestry-5 by apache.

the class Analyzer method computeMaxLocals.

/**
 * Computes and returns the maximum number of local variables used in the given method.
 *
 * @param method a method.
 * @return the maximum number of local variables used in the given method.
 */
private static int computeMaxLocals(final MethodNode method) {
    int maxLocals = Type.getArgumentsAndReturnSizes(method.desc) >> 2;
    for (AbstractInsnNode insnNode : method.instructions) {
        if (insnNode instanceof VarInsnNode) {
            int local = ((VarInsnNode) insnNode).var;
            int size = (insnNode.getOpcode() == Opcodes.LLOAD || insnNode.getOpcode() == Opcodes.DLOAD || insnNode.getOpcode() == Opcodes.LSTORE || insnNode.getOpcode() == Opcodes.DSTORE) ? 2 : 1;
            maxLocals = Math.max(maxLocals, local + size);
        } else if (insnNode instanceof IincInsnNode) {
            int local = ((IincInsnNode) insnNode).var;
            maxLocals = Math.max(maxLocals, local + 1);
        }
    }
    return maxLocals;
}

Example 2 with VarInsnNode

use of org.apache.tapestry5.internal.plastic.asm.tree.VarInsnNode 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;
}