Example usage for org.objectweb.asm MethodVisitor visitLabel

List of usage examples for org.objectweb.asm MethodVisitor visitLabel

  1. HOME
  2. Java
  3. org.objectweb.asm
  4. org.objectweb.asm.*
  5. MethodVisitor
  6. visitLabel

Introduction

In this page you can find the example usage for org.objectweb.asm MethodVisitor visitLabel.

Prototype

public void visitLabel(final Label label)

Source Link

Document

Visits a label.

Usage

From source file:jtaint.StringAdapter.java

License:Apache License

/** Add a new constructor to a create a (partially or fully) tainted 
 * String. Equivalent to the following Java code:
 *
 * public String(String original, Taint t) {
 *     super();//from www . jav a  2s .  c  om
 *     this.count = original.count;
 *
 *     if (!t.isTainted()) {
 *         this.offset = original.offset;
 *         this.value = original.value;
 *         this.tainted = original.tainted;
 *         return
 *     }
 *
 *     this.offset = 0;
 *     this.value = jtaint.StringUtil.taintToString(original, t)
 *     if (this.value.length == this.count)
 *         this.tainted = false;
 *     else
 *         this.tainted = true;
 *     return;
 * The final check (if value.length == count) is true only when an error
 * occurs during the execution of taintToString
 */

private void addConstructor(ClassVisitor cv) {
    MethodVisitor mv = cv.visitMethod(ACC_PUBLIC, "<init>", "(Ljava/lang/String;Ljtaint/Taint;)V", null, null);
    mv.visitCode();
    mv.visitVarInsn(ALOAD, 0);
    mv.visitMethodInsn(INVOKESPECIAL, "java/lang/Object", "<init>", "()V");

    copyField(mv, "count", "I");

    Label l0 = new Label();
    mv.visitVarInsn(ALOAD, 2);
    mv.visitMethodInsn(INVOKEVIRTUAL, "jtaint/Taint", "isTainted", "()Z");
    mv.visitJumpInsn(IFNE, l0);

    /* Taint object is actually untainted, copy all fields and return */
    copyField(mv, "offset", "I");
    copyField(mv, "value", "[C");
    copyField(mv, ByteCodeUtil.internalName("tainted"), "Z");
    mv.visitInsn(RETURN);

    mv.visitLabel(l0);
    if (version == V1_6)
        mv.visitFrame(F_SAME, 0, null, 0, null);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitInsn(ICONST_0);
    mv.visitFieldInsn(PUTFIELD, className, "offset", "I");

    mv.visitVarInsn(ALOAD, 0);
    mv.visitVarInsn(ALOAD, 1);
    mv.visitVarInsn(ALOAD, 2);
    mv.visitMethodInsn(INVOKESTATIC, "jtaint/StringUtil", "taintToString",
            "(Ljava/lang/String;Ljtaint/Taint;)[C");
    mv.visitInsn(DUP_X1);
    mv.visitFieldInsn(PUTFIELD, className, "value", "[C");
    mv.visitInsn(ARRAYLENGTH);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitFieldInsn(GETFIELD, className, "count", "I");

    Label l1 = new Label();
    mv.visitJumpInsn(IF_ICMPEQ, l1);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitInsn(ICONST_1);
    mv.visitFieldInsn(PUTFIELD, className, ByteCodeUtil.internalName("tainted"), "Z");
    mv.visitInsn(RETURN);

    mv.visitLabel(l1);
    if (version == V1_6)
        mv.visitFrame(F_SAME, 0, null, 0, null);
    mv.visitVarInsn(ALOAD, 0);
    mv.visitInsn(ICONST_0);
    mv.visitFieldInsn(PUTFIELD, className, ByteCodeUtil.internalName("tainted"), "Z");

    mv.visitInsn(RETURN);

    mv.visitMaxs(3, 3);
    mv.visitEnd();
}

From source file:jtaint.XssAdapter.java

License:Apache License

private void buildWriteIntWrapper(final MethodVisitor mv, final String methodName, final String desc) {
    new XssLockBuilder(mv, version, className, methodName, desc) {
        public void onUnlocked() {
            mv.visitVarInsn(ALOAD, 0);//w ww.j a v a 2  s . co m
            mv.visitMethodInsn(INVOKEVIRTUAL, className, ByteCodeUtil.internalName("getHtmlValidator"),
                    "()Ljtaint/HtmlValidator;");

            if ("javax/servlet/ServletOutputStream".equals(className)) {
                mv.visitVarInsn(ILOAD, 1);
                mv.visitInsn(I2B);
                mv.visitMethodInsn(INVOKEVIRTUAL, "jtaint/HtmlValidator", "write", "(B)V");
            } else if ("java/io/PrintWriter".equals(className)) {
                mv.visitVarInsn(ILOAD, 1);
                mv.visitInsn(I2C);
                mv.visitMethodInsn(INVOKEVIRTUAL, "jtaint/HtmlValidator", "print", "(C)V");
            } else {
                /* Runtime check required */
                Label l0 = new Label();
                Label l1 = new Label();

                mv.visitVarInsn(ALOAD, 0);
                mv.visitTypeInsn(INSTANCEOF, "java/io/PrintWriter");
                mv.visitJumpInsn(IFNE, l1);

                /* If-branch, we're a ServletOutputStream.  */
                mv.visitVarInsn(ILOAD, 1);
                mv.visitInsn(I2B);
                mv.visitMethodInsn(INVOKEVIRTUAL, "jtaint/HtmlValidator", "write", "(B)V");
                mv.visitJumpInsn(GOTO, l0);

                /* Else-branch, we're a PrintWriter  */
                mv.visitLabel(l1);
                if (version == V1_6)
                    mv.visitFrame(F_SAME1, 0, null, 1, new Object[] { "jtaint/HtmlValidator" });

                mv.visitVarInsn(ILOAD, 1);
                mv.visitInsn(I2C);
                mv.visitMethodInsn(INVOKEVIRTUAL, "jtaint/HtmlValidator", "print", "(C)V");
                mv.visitLabel(l0);
                if (version == V1_6) {
                    mv.visitFrame(F_SAME, 0, null, 0, null);
                    /* We can't end on a visitFrame because 
                     * InstrumentationLockAdapter performs a visitFrame 
                     * after this method completes. Two consecutive 
                     * visitFrames cause the Java 6 type checker to barf, 
                     * so just pad with a single NOP.
                     */
                    mv.visitInsn(NOP);
                }
            }
        }
    }.build();
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

void genCall(MethodVisitor mv) {
    mv.visitLabel(callLabel);
    loadVar(mv, TOBJECT, methodWeaver.getFiberVar());
    mv.visitMethodInsn(INVOKEVIRTUAL, FIBER_CLASS, "down", "()" + D_FIBER);
    MethodInsnNode mi = getMethodInsn();
    if (mi.desc.indexOf(fiberArg) == -1) {
        // Don't add another fiberarg if it already has one. It'll already
        // have one if we have copied jsr instructions and modified the 
        // same instruction node earlier. 
        mi.desc = mi.desc.replace(")", fiberArg);
    }//from w  ww  .j  a  v a  2s.  com
    mi.accept(mv);
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

/**
 * After the pausable method call is over, we have four possibilities. The
 * called method yielded, or it returned normally. Orthogonally, we have
 * saved state or not. fiber.up() returns the combined status
 * /*w  w w . j  a  v  a2  s. co m*/
?     * <pre>
 *                     
 * switch (fiber.up()) {
 *    default:
 *    0: goto RESUME; // Not yielding , no State --  resume normal operations
 *    1: goto RESTORE; // Not yielding, has State -- restore state before resuming
 *    2: goto SAVE; // Yielding, no state -- save state before unwinding stack
 *    3: goto UNWIND // Yielding, has state -- nothing to do but unwind.
 * }
 * SAVE:
 *     ...
 *     xRETURN
 * UNWIND:
 *     ...
 *     xRETURN
 * RESTORE:
 *     ...
 *     // fall through to RESUME
 * RESUME:
 *     ... original code
 * </pre>
 * 
 * @param mv
 * 
 */
void genPostCall(MethodVisitor mv) {
    loadVar(mv, TOBJECT, methodWeaver.getFiberVar());
    mv.visitMethodInsn(INVOKEVIRTUAL, FIBER_CLASS, "up", "()I");
    Label restoreLabel = new Label();
    Label saveLabel = new Label();
    Label unwindLabel = new Label();
    Label[] labels = new Label[] { resumeLabel, restoreLabel, saveLabel, unwindLabel };
    mv.visitTableSwitchInsn(0, 3, resumeLabel, labels);
    genSave(mv, saveLabel);
    genUnwind(mv, unwindLabel);
    genRestore(mv, restoreLabel);
    mv.visitLabel(resumeLabel);
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

/**
 * Code for the case where we are yielding, and we have state built up from
 * a previous call. There's nothing meaningful to do except keep the
 * verifier happy. Pop the bottom stack, then return a dummy return value
 * (if this method -- note: not the called method -- returns a value)
 * //  ww w . ja  v  a2 s. c  om
 * @param mv
 */
private void genUnwind(MethodVisitor mv, Label unwindLabel) {
    mv.visitLabel(unwindLabel);
    // After the call returns, the stack would be left with numBottom plus
    // return value

    // pop callee's dummy return value first
    String rdesc = getReturnType();
    if (rdesc != D_VOID) {
        mv.visitInsn(TypeDesc.isDoubleWord(rdesc) ? POP2 : POP);
    }
    // pop numbottom
    int i = getNumBottom() - 1; // the numBottom'th element
    Frame f = bb.startFrame;
    for (; i >= 0; i--) {
        mv.visitInsn(f.getStack(i).isCategory1() ? POP : POP2);
    }

    // Now for the return value of this (the calling) method
    rdesc = TypeDesc.getReturnTypeDesc(bb.flow.desc);
    if (rdesc != D_VOID) {
        // ICONST_0; IRETURN or ACONST_NULL; ARETURN etc.
        int vmt = VMType.toVmType(rdesc);
        mv.visitInsn(VMType.constInsn[vmt]);
        mv.visitInsn(VMType.retInsn[vmt]);
    } else {
        mv.visitInsn(RETURN);
    }
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

/**
 * Yielding, but state hasn't been captured yet. We create a state object
 * and save each object in valInfoList in its corresponding field.
 * /*from w  ww .  j a v a2  s. c o  m*/
 * Note that we save each stack item into a scratch register before loading
 * it into a field. The reason is that we need to get the State ref under
 * the stack item before we can do a putfield. The alternative is to load
 * the State item, then do a swap or a dup_x2;pop (depending on the value's
 * category). We'll go with the earlier approach because stack manipulations
 * don't seem to perform as well in the current crop of JVMs.
 * 
 * @param mv
 */
private void genSave(MethodVisitor mv, Label saveLabel) {
    mv.visitLabel(saveLabel);

    Frame f = bb.startFrame;
    // pop return value if any.
    String retType = getReturnType();
    if (retType != D_VOID) {
        // Yielding, so the return value from the called
        // function is a dummy value
        mv.visitInsn(TypeDesc.isDoubleWord(retType) ? POP2 : POP);
    }
    /*
     * Instantiate state class. Call one of new xxxState(this, pc, fiber),
     * or new xxxState(pc, fiber) depending whether this method is static or
     * not. Note that are not referring to the called method.
     * 
     * pc, "the program counter" is merely the index of the call weaver in
     * the method weaver's list. This allows us to do a switch in the
     * method's entry.
     */
    mv.visitTypeInsn(NEW, stateClassName);
    mv.visitInsn(DUP); // 
    // call constructor
    mv.visitMethodInsn(INVOKESPECIAL, stateClassName, "<init>", "()V");
    // save state in register
    int stateVar = allocVar(1);
    storeVar(mv, TOBJECT, stateVar);
    // state.self = this if the current executing method isn't static
    if (!bb.flow.isStatic()) {
        loadVar(mv, TOBJECT, stateVar);
        mv.visitInsn(ALOAD_0); // for state.self == this
        mv.visitFieldInsn(PUTFIELD, STATE_CLASS, "self", D_OBJECT);
    }
    int pc = methodWeaver.getPC(this);
    loadVar(mv, TOBJECT, stateVar); // state.pc
    if (pc < 6) {
        mv.visitInsn(ICONST_0 + pc);
    } else {
        mv.visitIntInsn(BIPUSH, pc);
    }
    mv.visitFieldInsn(PUTFIELD, STATE_CLASS, "pc", D_INT);

    // First save bottom stack into state
    int i = getNumBottom() - 1;
    for (; i >= 0; i--) {
        Value v = f.getStack(i);
        ValInfo vi = valInfoList.find(v);
        if (vi == null) {
            // it must be a constant or a duplicate, which is why we don't
            // have any information on it. just pop it.
            mv.visitInsn(v.category() == 2 ? POP2 : POP);
        } else {
            /**
             * xstore <scratchVar> ; send stack elem to some local var 
             * aload <stateVar>    ; load state 
             * xload <scratchVar>  ; get stack elem back 
             * putfield ...        ; state.fx =
             */
            int var = allocVar(vi.val.category());
            storeVar(mv, vi.vmt, var);
            loadVar(mv, VMType.TOBJECT, stateVar);
            loadVar(mv, vi.vmt, var);
            mv.visitFieldInsn(PUTFIELD, stateClassName, vi.fieldName, vi.fieldDesc());
            releaseVar(var, vi.val.category());
        }
    }

    // Now load up registers into fields
    int fieldNum = 0;
    for (ValInfo vi : valInfoList) {
        // Ignore values on stack
        if (vi.var == -1)
            continue;
        // aload state var
        // xload <var>
        loadVar(mv, TOBJECT, stateVar);
        loadVar(mv, vi.vmt, vi.var);
        mv.visitFieldInsn(PUTFIELD, stateClassName, vi.fieldName, vi.fieldDesc());
        fieldNum++;
    }

    // Fiber.setState(state);
    loadVar(mv, TOBJECT, methodWeaver.getFiberVar());
    loadVar(mv, TOBJECT, stateVar);
    mv.visitMethodInsn(INVOKEVIRTUAL, FIBER_CLASS, "setState", "(" + D_STATE + ")V");
    releaseVar(stateVar, 1);
    // Figure out the return type of the calling method and issue the
    // appropriate xRETURN instruction
    retType = TypeDesc.getReturnTypeDesc(bb.flow.desc);
    if (retType == D_VOID) {
        mv.visitInsn(RETURN);
    } else {
        int vmt = VMType.toVmType(retType);
        // ICONST_0, DCONST_0 etc.
        mv.visitInsn(VMType.constInsn[vmt]);
        // IRETURN, DRETURN, etc.
        mv.visitInsn(VMType.retInsn[vmt]);
    }
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

/**
 * Not yielding (resuming normally), but have stored state. We need to
 * restore from state before resuming. This is slightly more work than
 * saving state, because we have to restore constants and duplicates too.
 * <b>/*from   w  ww  .ja va 2  s  .  c om*/
 * 
 * Note that the return value (if any) has a real value, which is why it
 * needs to be saved away before we can get access to the bottom elements to
 * pop them out.
 * 
 * <pre>
 *           If there is anything at the bottom save return value in scratch register
 *                 pop unnecessary bottom stuff.
 *          
 *           load fiber.curState 
 *           cast to specific state (if necessary) 
 *           astore in scratch &lt;stateVar&gt;
 *          
 *          for each value in frame.var 
 *               if val is constant or is in valInfoList, 
 *                   push constant or load field (appropriately) 
 *          for each value in bottom stack
 *                 restore value similar to above 
 *          restore return value if any from scratch register
 * </pre>
 */
private void genRestore(MethodVisitor mv, Label restoreLabel) {
    mv.visitLabel(restoreLabel);
    Frame f = bb.startFrame;
    int numBottom = getNumBottom();
    int retVar = -1;
    int retctype = -1;
    if (numBottom > 0) {
        // We have dummy values sitting in the stack. pop 'em.
        // But first, check if we have a real return value on top
        String retType = getReturnType();
        if (retType != D_VOID) {
            // .. yep. save it to scratch register
            retctype = VMType.toVmType(retType);
            retVar = allocVar(VMType.category[retctype]);
            storeVar(mv, retctype, retVar);
        }
        // pop dummy values from stack bottom
        for (int i = numBottom - 1; i >= 0; i--) {
            Value v = f.getStack(i);
            int insn = v.isCategory1() ? POP : POP2;
            mv.visitInsn(insn);
        }
    }
    // Restore variables from state
    int stateVar = -1;
    if (valInfoList.size() > 0) {
        stateVar = allocVar(1);
    }
    genRestoreVars(mv, stateVar);

    // Now restore the bottom values in the stack from state
    for (int i = 0; i < numBottom; i++) {
        Value v = f.getStack(i);
        if (v.isConstant()) {
            loadConstant(mv, v);
        } else {
            ValInfo vi = valInfoList.find(v);
            if (vi.var == -1) {
                loadVar(mv, TOBJECT, stateVar);
                mv.visitFieldInsn(GETFIELD, stateClassName, vi.fieldName, vi.fieldDesc());
                checkcast(mv, v);
            } else {
                // this stack value is a duplicate of a local var, which has
                // already been loaded and is of the right type
                loadVar(mv, vi.vmt, vi.var);
            }
        }
    }

    // restore the saved return value, if any
    // But we would have popped and saved the return value only
    // if there were any dummy values in the stack bottom to be
    // cleared out. If not, we wouldn't have bothered
    // popping the return value in the first place.
    if (numBottom > 0) {
        if (retVar != -1) {
            loadVar(mv, retctype, retVar);
        }
    }
    releaseVar(stateVar, 1);
    if (retctype != -1) {
        releaseVar(retVar, VMType.category[retctype]);
    }
    // Fall through to the resumeLabel in genNY_NS, so no goto required.
}

From source file:kilim.analysis.CallWeaver.java

License:Open Source License

void genRestoreEx(MethodVisitor mv, Label restoreLabel) {
    mv.visitLabel(restoreLabel);
    int stateVar = -1;
    if (valInfoList.size() > 0) {
        stateVar = allocVar(1);// w  w  w. j  a  v  a2  s . c  om
    }
    genRestoreVars(mv, stateVar);
    releaseVar(stateVar, 1);
}

From source file:kilim.analysis.MethodFlow.java

License:Open Source License

@Override
/**//w  w  w .ja v  a2  s . co m
 * Copied verbatim from MethodNode except for the instruction processing.
 * Unlike MethodNode, we don't keep LabelNodes inline, so we need to 
 * do visitLabel ourselves.
 * 
 * @param mv a method visitor.
 */
public void accept(final MethodVisitor mv) {
    // visits the method attributes
    int i, j, n;
    if (annotationDefault != null) {
        AnnotationVisitor av = mv.visitAnnotationDefault();
        acceptAnnotation(av, null, annotationDefault);
        av.visitEnd();
    }
    n = visibleAnnotations == null ? 0 : visibleAnnotations.size();
    for (i = 0; i < n; ++i) {
        AnnotationNode an = (AnnotationNode) visibleAnnotations.get(i);
        an.accept(mv.visitAnnotation(an.desc, true));
    }
    n = invisibleAnnotations == null ? 0 : invisibleAnnotations.size();
    for (i = 0; i < n; ++i) {
        AnnotationNode an = (AnnotationNode) invisibleAnnotations.get(i);
        an.accept(mv.visitAnnotation(an.desc, false));
    }
    n = visibleParameterAnnotations == null ? 0 : visibleParameterAnnotations.length;
    for (i = 0; i < n; ++i) {
        List<?> l = visibleParameterAnnotations[i];
        if (l == null) {
            continue;
        }
        for (j = 0; j < l.size(); ++j) {
            AnnotationNode an = (AnnotationNode) l.get(j);
            an.accept(mv.visitParameterAnnotation(i, an.desc, true));
        }
    }
    n = invisibleParameterAnnotations == null ? 0 : invisibleParameterAnnotations.length;
    for (i = 0; i < n; ++i) {
        List<?> l = invisibleParameterAnnotations[i];
        if (l == null) {
            continue;
        }
        for (j = 0; j < l.size(); ++j) {
            AnnotationNode an = (AnnotationNode) l.get(j);
            an.accept(mv.visitParameterAnnotation(i, an.desc, false));
        }
    }
    n = attrs == null ? 0 : attrs.size();
    for (i = 0; i < n; ++i) {
        mv.visitAttribute((Attribute) attrs.get(i));
    }
    // visits the method's code
    if (instructions.size() > 0) {
        mv.visitCode();
        // visits try catch blocks
        for (i = 0; i < tryCatchBlocks.size(); ++i) {
            ((TryCatchBlockNode) tryCatchBlocks.get(i)).accept(mv);
        }
        // visits instructions
        for (i = 0; i < instructions.size(); ++i) {
            Label l = getLabelAt(i);
            if (l != null) {
                mv.visitLabel(l);
            }
            ((AbstractInsnNode) instructions.get(i)).accept(mv);
        }
        Label l = getLabelAt(instructions.size());
        if (l != null) {
            mv.visitLabel(l);
        }
        // visits local variables
        n = localVariables == null ? 0 : localVariables.size();
        for (i = 0; i < n; ++i) {
            ((LocalVariableNode) localVariables.get(i)).accept(mv);
        }
        // visits line numbers
        /* TODO this was in ASM 2.3.3 but not 3.x or 4.0, find a substitute or remove
                    n = lineNumbers == null ? 0 : lineNumbers.size();
                    for (i = 0; i < n; ++i) {
        ((LineNumberNode) lineNumbers.get(i)).accept(mv);
                    }
        */
        // visits maxs
        mv.visitMaxs(maxStack, maxLocals);
    }
    mv.visitEnd();
}

From source file:kilim.analysis.MethodWeaver.java

License:Open Source License

private void visitInstructions(MethodVisitor mv) {
    //TODO gen code for pausable JSRs 
    genPrelude(mv);//from w w  w .  ja  v  a2 s  . com
    MethodFlow mf = methodFlow;
    BasicBlock lastBB = null;
    for (BasicBlock bb : mf.getBasicBlocks()) {
        int from = bb.startPos;

        if (bb.isPausable() && bb.startFrame != null) {
            genPausableMethod(mv, bb);
            from = bb.startPos + 1; // first instruction is consumed
        } else if (bb.isCatchHandler()) {
            List<CallWeaver> cwList = getCallsUnderCatchBlock(bb);
            if (cwList != null) {
                genException(mv, bb, cwList);
                from = bb.startPos + 1; // first instruction is consumed
            } // else no different from any other block
        }
        int to = bb.endPos;
        for (int i = from; i <= to; i++) {
            Label l = mf.getLabelAt(i);
            if (l != null) {
                mv.visitLabel(l);
            }
            bb.getInstruction(i).accept(mv);
        }
        lastBB = bb;
    }
    if (lastBB != null) {
        Label l = methodFlow.getLabelAt(lastBB.endPos + 1);
        if (l != null) {
            mv.visitLabel(l);
        }
    }
}