Example usage for org.objectweb.asm Label getOffset

List of usage examples for org.objectweb.asm Label getOffset

Introduction

In this page you can find the example usage for org.objectweb.asm Label getOffset.

Prototype

public int getOffset() 

Source Link

Document

Returns the bytecode offset corresponding to this label.

Usage

From source file:com.gargoylesoftware.js.nashorn.internal.ir.debug.NashornTextifier.java

License:Open Source License

private StringBuilder appendOpcode(final StringBuilder sb, final int opcode) {
    final Label next = getNextLabel();
    if (next instanceof NashornLabel) {
        final int bci = next.getOffset();
        if (bci != -1) {
            final String bcis = "" + bci;
            for (int i = 0; i < 5 - bcis.length(); i++) {
                sb.append(' ');
            }/*from www .  j  ava 2 s  . c  o m*/
            sb.append(bcis);
            sb.append(' ');
        } else {
            sb.append("       ");
        }
    }

    return sb.append(tab2).append(OPCODES[opcode].toLowerCase());
}

From source file:com.google.java.contract.core.agent.SpecificationMethodAdapter.java

License:Open Source License

/**
 * Returns {@code true} if the specified label is resolved, that is,
 * is associated with an offset in the bytecode of the method.
 *///from w  w  w  .  ja v  a 2s  .com
@Requires("label != null")
protected static boolean labelIsResolved(Label label) {
    try {
        label.getOffset();
    } catch (IllegalStateException e) {
        return false;
    }
    return true;
}

From source file:org.jboss.byteman.agent.adapter.BMInsnList.java

License:Open Source License

public void accept(final MethodVisitor mv) {
    // this method visitor must implement LocalScopeMethodVisitor or else we woudl not be here

    LocalScopeMethodVisitor lsmv = (LocalScopeMethodVisitor) mv;

    // first index all local vars by start and end label
    HashMap<Label, LinkedList<LocalVariableNode>> localStarts = new HashMap<Label, LinkedList<LocalVariableNode>>();
    HashMap<Label, LinkedList<LocalVariableNode>> localEnds = new HashMap<Label, LinkedList<LocalVariableNode>>();

    Iterator iterator = localvariables.iterator();
    while (iterator.hasNext()) {
        LocalVariableNode local = (LocalVariableNode) iterator.next();
        Label label = local.start.getLabel();
        LinkedList<LocalVariableNode> locals = localStarts.get(label);
        if (locals == null) {
            locals = new LinkedList<LocalVariableNode>();
            localStarts.put(label, locals);
        }//from   w w w .ja  v  a 2  s  .c o m
        locals.addLast(local);
        label = local.end.getLabel();
        locals = localEnds.get(label);
        if (locals == null) {
            locals = new LinkedList<LocalVariableNode>();
            localEnds.put(label, locals);
        }
        locals.addLast(local);
    }

    // now visit the instructions intercepting labels
    AbstractInsnNode insn = getFirst();
    while (insn != null) {
        insn.accept(mv);
        if (insn.getType() == AbstractInsnNode.LABEL) {
            LabelNode labelNode = (LabelNode) insn;
            Label label = labelNode.getLabel();
            List<LocalVariableNode> localStart = localStarts.get(label);
            List<LocalVariableNode> localEnd = localEnds.get(label);
            if (localStart != null) {
                for (LocalVariableNode local : localStart) {
                    lsmv.visitLocalScopeStart(local.name, local.desc, local.signature, local.index,
                            label.getOffset());
                }
            }
            if (localEnd != null) {
                for (LocalVariableNode local : localEnd) {
                    lsmv.visitLocalScopeEnd(local.name, local.desc, local.signature, local.index,
                            label.getOffset());
                }
            }
        }
        insn = insn.getNext();
    }
}

From source file:org.jboss.byteman.agent.adapter.cfg.BBlock.java

License:Open Source License

/**
 * write a string represenattion of this block to the buffer
 * @param buf the buffer to be written to
 * @return/*from   w w  w .  jav a  2 s. c  om*/
 */
void printTo(StringBuffer buf) {
    int blockIdx = this.getBlockIdx();
    buf.append(this.getLabel().getOffset());
    buf.append(": BB ");
    buf.append(blockIdx);
    buf.append("\n");
    FanOut containsFanOut = cfg.getContains(this);
    Iterator<Label> containsIter;
    Label containedLabel;
    int containedPosition;
    if (containsFanOut != null) {
        containsIter = containsFanOut.iterator();
        if (containsIter.hasNext()) {
            containedLabel = containsIter.next();
            containedPosition = cfg.getBlockInstructionIdx(containedLabel);
        } else {
            containedLabel = null;
            containedPosition = -1;
        }
    } else {
        containsIter = null;
        containedLabel = null;
        containedPosition = -1;
    }

    int instructionCount = this.getInstructionCount();
    for (int i = 0; i < instructionCount; i++) {
        // we will never enter this if containedPosition is -1 which safeguards us when containsIter
        // is null or containedLabel is null
        while (containedPosition == i) {
            buf.append(containedLabel.getOffset());
            buf.append(": ");
            buf.append(containedLabel);
            buf.append(" +");
            buf.append(containedPosition);
            if (cfg.tryCatchStart(containedLabel)) {
                List<TryCatchDetails> detailsList = cfg.tryCatchStartDetails(containedLabel);
                int detailsCount = detailsList.size();
                for (int j = 0; j < detailsCount; j++) {
                    TryCatchDetails details = detailsList.get(j);
                    Label handlerLabel = details.getHandler();
                    CodeLocation handlerLocation = cfg.getLocation(handlerLabel);
                    buf.append(" try ");
                    buf.append(details.getType());
                    buf.append(" ");
                    if (handlerLocation != null) {
                        buf.append(handlerLabel.getOffset());
                    } else {
                        buf.append("??");
                    }
                    buf.append(" ");
                    buf.append(handlerLabel);
                }
            }
            if (cfg.tryCatchEnd(containedLabel)) {
                List<TryCatchDetails> detailsList = cfg.tryCatchEndDetails(containedLabel);
                int detailsCount = detailsList.size();
                for (int j = 0; j < detailsCount; j++) {
                    TryCatchDetails details = detailsList.get(j);
                    Label handlerLabel = details.getHandler();
                    CodeLocation handlerLocation = cfg.getLocation(handlerLabel);
                    buf.append(" catch ");
                    buf.append(details.getType());
                    buf.append(" ");
                    if (handlerLocation != null) {
                        buf.append(handlerLabel.getOffset());
                    } else {
                        buf.append("??");
                    }
                    buf.append(" ");
                    buf.append(handlerLabel);
                }
            }
            if (cfg.tryCatchHandlerStart(containedLabel)) {
                List<TryCatchDetails> detailsList = cfg.tryCatchHandlerStartDetails(containedLabel);
                int detailsCount = detailsList.size();
                for (int j = 0; j < detailsCount; j++) {
                    TryCatchDetails details = detailsList.get(j);
                    buf.append(" handle ");
                    buf.append(details.getType());
                    buf.append(" ");
                    buf.append(details.getStart().getOffset());
                    buf.append(" ");
                    buf.append(details.getEnd().getOffset());
                }
            }
            if (cfg.triggerStart(containedLabel)) {
                buf.append(" trigger start");
                TriggerDetails details = cfg.triggerStartDetails(containedLabel);
            }
            if (cfg.triggerEnd(containedLabel)) {
                buf.append(" trigger end");
            }
            buf.append("\n");
            List<CodeLocation> openEnters = cfg.getOpenMonitorEnters(containedLabel);
            if (openEnters != null) {
                int openCount = openEnters.size();
                if (openCount > 0) {
                    buf.append("open monitors: ");
                    for (int j = 0; j < openCount; j++) {
                        CodeLocation l = openEnters.get(j);
                        buf.append(" BB");
                        buf.append(l.getBlock().getBlockIdx());
                        buf.append(".");
                        buf.append(l.getInstructionIdx());
                    }
                    buf.append('\n');
                }
            }
            containedLabel = (containsIter.hasNext() ? containsIter.next() : null);
            containedPosition = (containedLabel != null ? cfg.getBlockInstructionIdx(containedLabel) : -1);
        }
        // buf.append("   ");
        buf.append(blockIdx);
        buf.append(".");
        buf.append(i);
        buf.append(": ");
        int opcode = this.getInstruction(i);
        switch (OpcodesHelper.insnType(opcode)) {
        case OpcodesHelper.INSN_NONE: {
            // print the instruction name
            buf.append(OpcodesHelper.insnName(opcode));
            if (opcode == Opcodes.MONITOREXIT) {
                CodeLocation exit = new CodeLocation(this, i);
                CodeLocation enter = cfg.getPairedEnter(exit);
                // print the corresponding open instruction
                buf.append(" (enter: ");
                buf.append(enter);
                buf.append(")");
            }
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_INT: {
            // just print the instruction name and one integer argument
            int intValue = this.getInstructionArg(i, 0);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(intValue);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_LDC: {
            // print the instruction and one constant argument
            int nameIdx = this.getInstructionArg(i, 0);
            String name = cfg.getName(nameIdx);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(name);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_VAR: {
            // print the instruction and the var idx
            int varIdx = this.getInstructionArg(i, 0);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(varIdx);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_IINC: {
            // print the instruction and the var idx
            int increment = this.getInstructionArg(i, 0);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(increment);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_JUMP: {
            // note that we may not have generated the code for the jump target yet
            Label targetLabel = this.firstOut();
            CodeLocation targetLocation = cfg.getLocation(targetLabel);
            int targetPos = (targetLocation != null ? targetLabel.getOffset() : -1);
            switch (opcode) {
            case Opcodes.IFEQ:
                buf.append("IFEQ ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFNE:
                buf.append("IFNE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFLT:
                buf.append("IFLT ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFGE:
                buf.append("IFGE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFGT:
                buf.append("IFGT ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFLE:
                buf.append("IFLE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPEQ:
                buf.append("IF_ICMPEQ ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPNE:
                buf.append("IF_ICMPNE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPLT:
                buf.append("IF_ICMPLT ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPGE:
                buf.append("IF_ICMPGE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPGT:
                buf.append("IF_ICMPGT ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ICMPLE:
                buf.append("IF_ICMPLE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ACMPEQ:
                buf.append("IF_ACMPEQ ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IF_ACMPNE:
                buf.append("IF_ACMPNE ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.GOTO:
                buf.append("GOTO ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.JSR:
                buf.append("JSR ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFNULL:
                buf.append("IFNULL ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            case Opcodes.IFNONNULL:
                buf.append("IFNONNULL ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
                buf.append("\n");
                break;
            }
        }
            break;
        case OpcodesHelper.INSN_TSWITCH: {
            Label targetLabel;
            CodeLocation targetLocation;
            int targetPos;
            // print the instruction followed by the jump table discriminant min and max and then
            // the jump labels
            int min = this.getInstructionArg(i, 0);
            int max = this.getInstructionArg(i, 1);
            int count = (max + 1 - min);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(min);
            buf.append(" ");
            buf.append(max);
            buf.append("\n");
            for (int j = 1; j <= count; j++) {
                // note that we may not have generated the code for the jump target yet
                targetLabel = this.nthOut(j);
                targetLocation = cfg.getLocation(targetLabel);
                targetPos = (targetLocation != null ? targetLabel.getOffset() : -1);
                buf.append("    ");
                buf.append(min + j);
                buf.append(" : ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
            }
            targetLabel = this.firstOut();
            targetLocation = cfg.getLocation(targetLabel);
            targetPos = (targetLocation != null ? targetLabel.getOffset() : -1);
            buf.append("    dflt : ");
            if (targetPos >= 0) {
                buf.append(targetPos);
                buf.append(" BB ");
                buf.append(targetLocation.getBlock().getBlockIdx());
                buf.append(" ");
                buf.append(targetLabel);
            } else {
                buf.append("??  ");
                buf.append(targetLabel);
            }
        }
            break;
        case OpcodesHelper.INSN_LOOKUP: {
            Label targetLabel;
            CodeLocation targetLocation;
            int targetPos;
            // print the instruction followed by each jump table discriminant and label
            int count = this.getInstructionArg(i, 0);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append("\n");
            for (int j = 1; j <= count; j++) {
                // note that we may not have generated the code for the jump target yet
                targetLabel = this.nthOut(j);
                targetLocation = cfg.getLocation(targetLabel);
                targetPos = (targetLocation != null ? targetLabel.getOffset() : -1);
                buf.append("    ");
                buf.append(this.getInstructionArg(i, j));
                buf.append(" : ");
                if (targetPos >= 0) {
                    buf.append(targetPos);
                    buf.append(" BB ");
                    buf.append(targetLocation.getBlock().getBlockIdx());
                    buf.append(" ");
                    buf.append(targetLabel);
                } else {
                    buf.append("??  ");
                    buf.append(targetLabel);
                }
            }
            targetLabel = this.firstOut();
            targetLocation = cfg.getLocation(targetLabel);
            targetPos = (targetLocation != null ? targetLabel.getOffset() : -1);
            buf.append("    dflt : ");
            if (targetPos >= 0) {
                buf.append(targetPos);
                buf.append(" BB ");
                buf.append(targetLocation.getBlock().getBlockIdx());
                buf.append(" ");
                buf.append(targetLabel);
            } else {
                buf.append("??  ");
                buf.append(targetLabel);
            }
        }
            break;
        case OpcodesHelper.INSN_FIELD:
        case OpcodesHelper.INSN_METHOD: {
            // print the instruction with the owner, name and descriptor
            int idx1 = this.getInstructionArg(i, 0);
            int idx2 = this.getInstructionArg(i, 1);
            int idx3 = this.getInstructionArg(i, 2);
            String owner = cfg.getName(idx1);
            String name = cfg.getName(idx2);
            String desc = cfg.getName(idx3);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(owner);
            buf.append(" ");
            buf.append(name);
            buf.append(" ");
            buf.append(desc);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_TYPE: {
            // print the instruction with the type name
            int idx = this.getInstructionArg(i, 0);
            String name = cfg.getName(idx);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(name);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_MULTIANEWARRAY: {
            // print the instruction with the typename and the dimension count
            int idx = this.getInstructionArg(i, 0);
            int dims = this.getInstructionArg(i, 1);
            String name = cfg.getName(idx);
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append(" ");
            buf.append(name);
            buf.append(" ");
            buf.append(dims);
            buf.append("\n");
        }
            break;
        case OpcodesHelper.INSN_UNUSED: {
            // print the instruction
            buf.append(OpcodesHelper.insnName(opcode));
            buf.append("!!!\n");
        }
            break;
        }
    }
    // print the active starts for this block
    if (activeTryStarts != null) {
        Iterator<TryCatchDetails> activeStartsIter = activeTryStarts.iterator();
        while (activeStartsIter.hasNext()) {
            TryCatchDetails details = activeStartsIter.next();
            Label label = details.getStart();
            BBlock block = cfg.getBlock(label);
            buf.append("try: ");
            if (block != null) {
                buf.append(label.getOffset());
                buf.append(" ");
                buf.append(block.getBlockIdx());
                buf.append(".");
                buf.append(cfg.getBlockInstructionIdx(label));
            } else {
                buf.append(label);
            }
            buf.append(" catch: ");
            label = details.getEnd();
            block = cfg.getBlock(label);
            if (block != null) {
                buf.append(label.getOffset());
                buf.append(" ");
                buf.append(block.getBlockIdx());
                buf.append(".");
                buf.append(cfg.getBlockInstructionIdx(label));
            } else {
                buf.append(label);
            }
            buf.append(" handle: ");
            label = details.getHandler();
            block = cfg.getBlock(label);
            if (block != null) {
                buf.append(label.getOffset());
                buf.append(" ");
                buf.append(block.getBlockIdx());
                buf.append(".");
                buf.append(cfg.getBlockInstructionIdx(label));
            } else {
                buf.append(label);
            }
            buf.append(" ");
            buf.append(details.getType());
            buf.append("\n");
        }
    }
}

From source file:org.jboss.byteman.agent.adapter.RuleGeneratorAdapter.java

License:Open Source License

private void dumpFrame(int nLocal, Object[] local, int nStack, Object[] stack) {
    StringBuffer buffer = new StringBuffer();
    String sepr;//from   ww  w .j  a v  a 2  s. co m
    Label l = new Label();
    visitLabel(l);
    buffer.append("Frame ");
    buffer.append(l.getOffset());
    buffer.append("\n");
    buffer.append("  locals ");
    buffer.append(nLocal);
    buffer.append("\n    ");
    sepr = "";
    for (int i = 0; i < nLocal; i++) {
        buffer.append(sepr);
        dumpType(buffer, local[i]);
        sepr = ",\n    ";
    }
    buffer.append("\n  stack ");
    buffer.append(nStack);
    buffer.append("\n    ");
    sepr = "";
    for (int i = 0; i < nStack; i++) {
        buffer.append(sepr);
        dumpType(buffer, stack[i]);
        sepr = ",\n    ";
    }
    System.out.println(buffer.toString());
}

From source file:org.openquark.cal.internal.javamodel.AsmJavaBytecodeGenerator.java

License:Open Source License

/**
 * Generate the exception table entry(/entries) for a try/catch block.
 * This can be done in any order, any time after all labels passed as arguments have been visited.
 * //ww w  .j a  v  a 2s .  com
 * Jump and return instructions are excluded from any exception handling blocks if they cause the next executed instruction 
 *   to escape the bounds of the try statement.
 * 
 * eg. if there is a return statement in a try block in a try-catch statement, the corresponding return instruction will
 *     be excluded from the exception table entry.
 *     if there is a jump (eg. goto) statement in a try block of a try-catch statement, the jump instruction will be
 *     excluded from the exception table entry if the jump destination lies outside the try statement.
 * 
 * Exclusion of the instruction will cause the exception table entry to be split or reduced:
 *   one entry will include the part before the excluded instruction, 
 *   the other will include the part after it, if it is not the instruction at the end of the block.
 * 
 * 
 * An interesting case to consider is a try/catch nested with respect to a while(true) statement, with a continue statement in the body:
 * 
 *     try {
 *         while (true) {
 *             (statements)
 *             continue;
 *             (more statements)
 *         }
 *     } catch (Exception e) {
 *     }
 * 
 *   versus
 * 
 *     while (true) {
 *         try {
 *             (statements)
 *             continue;
 *             (more statements)
 *         } catch (Exception e) {
 *         }
 *     }
 * 
 * In both cases, the continue is encoded as a goto instruction whose destination is the first instruction in (statements).
 * In the first case, the target "while" statement is nested within the try block, therefore the goto is not excluded.
 * In the second case, the target "while" statement is outside of the try block, therefore the goto is excluded.
 * ie. even though the instructions for the try body are the same, and the instructions for (statements) lies both within
 *   the while block and the try block, a jump to the first statement may or may not be viewed as escaping the try block,
 *   depending on which case was compiled.
 * 
 * 
 * @param tryStartLabel
 * @param tryEndLabel
 * @param catchLabel
 * @param exceptionType
 * @param tryBlockContext
 */
private static void encodeTryCatchBlock(Label tryStartLabel, Label tryEndLabel, Label catchLabel,
        JavaTypeName exceptionType, GenerationContext tryBlockContext) {

    MethodVisitor mv = tryBlockContext.getMethodVisitor();

    // The start label for the next table entry to be visited.
    Label exceptionEntryStartLabel = tryStartLabel;

    for (final JumpReturnLabelInfo jumpReturnLabelInfo : tryBlockContext.getJumpReturnLabelInfoList()) {

        // Only exclude the jump/return instruction (ie. split the exception block) 
        //   if the destination label is outside the scope of the try block
        Label destinationLabel = jumpReturnLabelInfo.getDestinationLabel();
        if (destinationLabel != null && tryBlockContext.containsStatementJumpLabel(destinationLabel)) {
            continue;
        }

        // The next entry goes from the start label (inclusive) to the return or continue label (exclusive).
        Label returnContinueLabel = jumpReturnLabelInfo.getInstructionLabel();
        if (exceptionEntryStartLabel.getOffset() != returnContinueLabel.getOffset()) {
            // When there are consecutive instructions which jump/return outside the scope of the try block,
            // after the first iteration of the loop we will have the exception entry start label and the
            // return continue label both pointing to the same offset (ie. the offset of the nth consecutive
            // jump/return instruction on iteration n).
            mv.visitTryCatchBlock(exceptionEntryStartLabel, returnContinueLabel, catchLabel,
                    exceptionType.getJVMInternalName());
        }

        // Set the start label for the next table entry to be visited.
        exceptionEntryStartLabel = jumpReturnLabelInfo.getAfterInstructionLabel(); // afterReturnLabel
    }

    // Check for the case where the last return instruction comes at the end of the try block.
    if (exceptionEntryStartLabel.getOffset() != tryEndLabel.getOffset()) {
        // Add the final entry, which ends at the tryEndLabel.
        mv.visitTryCatchBlock(exceptionEntryStartLabel, tryEndLabel, catchLabel,
                exceptionType.getJVMInternalName());
    }
}