Java Code Examples for com.sun.org.apache.bcel.internal.generic.InstructionList#getStart()

The following examples show how to use com.sun.org.apache.bcel.internal.generic.InstructionList#getStart() . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: TestSeq.java    From jdk1.8-source-analysis with Apache License 2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 2
Source File: TestSeq.java    From TencentKona-8 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 3
Source File: TestSeq.java    From jdk8u60 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 4
Source File: TestSeq.java    From JDKSourceCode1.8 with MIT License 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 5
Source File: TestSeq.java    From openjdk-jdk8u with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 6
Source File: TestSeq.java    From openjdk-jdk8u-backup with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 7
Source File: TestSeq.java    From Bytecoder with Apache License 2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 8
Source File: TestSeq.java    From openjdk-jdk9 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 9
Source File: TestSeq.java    From hottub with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 10
Source File: TestSeq.java    From openjdk-8-source with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}
Example 11
Source File: TestSeq.java    From openjdk-8 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Compile the code for this test sequence. Compile patterns
 * from highest to lowest priority. Note that since patterns
 * can be share by multiple test sequences, instruction lists
 * must be copied before backpatching.
 */
public InstructionHandle compile(ClassGenerator classGen,
                                 MethodGenerator methodGen,
                                 InstructionHandle continuation)
{
    // Returned cached value if already compiled
    if (_start != null) {
        return _start;
    }

    // If not patterns, then return handle for default template
    final int count = _patterns.size();
    if (count == 0) {
        return (_start = getTemplateHandle(_default));
    }

    // Init handle to jump when all patterns failed
    InstructionHandle fail = (_default == null) ? continuation
        : getTemplateHandle(_default);

    // Compile all patterns in reverse order
    for (int n = count - 1; n >= 0; n--) {
        final LocationPathPattern pattern = getPattern(n);
        final Template template = pattern.getTemplate();
        final InstructionList il = new InstructionList();

        // Patterns expect current node on top of stack
        il.append(methodGen.loadCurrentNode());

        // Apply the test-code compiled for the pattern
        InstructionList ilist = methodGen.getInstructionList(pattern);
        if (ilist == null) {
            ilist = pattern.compile(classGen, methodGen);
            methodGen.addInstructionList(pattern, ilist);
        }

        // Make a copy of the instruction list for backpatching
        InstructionList copyOfilist = ilist.copy();

        FlowList trueList = pattern.getTrueList();
        if (trueList != null) {
            trueList = trueList.copyAndRedirect(ilist, copyOfilist);
        }
        FlowList falseList = pattern.getFalseList();
        if (falseList != null) {
            falseList = falseList.copyAndRedirect(ilist, copyOfilist);
        }

        il.append(copyOfilist);

        // On success branch to the template code
        final InstructionHandle gtmpl = getTemplateHandle(template);
        final InstructionHandle success = il.append(new GOTO_W(gtmpl));

        if (trueList != null) {
            trueList.backPatch(success);
        }
        if (falseList != null) {
            falseList.backPatch(fail);
        }

        // Next pattern's 'fail' target is this pattern's first instruction
        fail = il.getStart();

        // Append existing instruction list to the end of this one
        if (_instructionList != null) {
            il.append(_instructionList);
        }

        // Set current instruction list to be this one
        _instructionList = il;
    }
    return (_start = fail);
}