generatoradapter.java

asm的源码包 并且包含英文的文档

     * @param local the local variable to be incremented.
     * @param amount the amount by which the local variable must be incremented.
     */
    public void iinc(final int local, final int amount) {
        mv.visitIincInsn(local, amount);
    }

    /**
     * Generates the instructions to cast a numerical value from one type to
     * another.
     * 
     * @param from the type of the top stack value
     * @param to the type into which this value must be cast.
     */
    public void cast(final Type from, final Type to) {
        if (from != to) {
            if (from == Type.DOUBLE_TYPE) {
                if (to == Type.FLOAT_TYPE) {
                    mv.visitInsn(Opcodes.D2F);
                } else if (to == Type.LONG_TYPE) {
                    mv.visitInsn(Opcodes.D2L);
                } else {
                    mv.visitInsn(Opcodes.D2I);
                    cast(Type.INT_TYPE, to);
                }
            } else if (from == Type.FLOAT_TYPE) {
                if (to == Type.DOUBLE_TYPE) {
                    mv.visitInsn(Opcodes.F2D);
                } else if (to == Type.LONG_TYPE) {
                    mv.visitInsn(Opcodes.F2L);
                } else {
                    mv.visitInsn(Opcodes.F2I);
                    cast(Type.INT_TYPE, to);
                }
            } else if (from == Type.LONG_TYPE) {
                if (to == Type.DOUBLE_TYPE) {
                    mv.visitInsn(Opcodes.L2D);
                } else if (to == Type.FLOAT_TYPE) {
                    mv.visitInsn(Opcodes.L2F);
                } else {
                    mv.visitInsn(Opcodes.L2I);
                    cast(Type.INT_TYPE, to);
                }
            } else {
                if (to == Type.BYTE_TYPE) {
                    mv.visitInsn(Opcodes.I2B);
                } else if (to == Type.CHAR_TYPE) {
                    mv.visitInsn(Opcodes.I2C);
                } else if (to == Type.DOUBLE_TYPE) {
                    mv.visitInsn(Opcodes.I2D);
                } else if (to == Type.FLOAT_TYPE) {
                    mv.visitInsn(Opcodes.I2F);
                } else if (to == Type.LONG_TYPE) {
                    mv.visitInsn(Opcodes.I2L);
                } else if (to == Type.SHORT_TYPE) {
                    mv.visitInsn(Opcodes.I2S);
                }
            }
        }
    }

    // ------------------------------------------------------------------------
    // Instructions to do boxing and unboxing operations
    // ------------------------------------------------------------------------

    /**
     * Generates the instructions to box the top stack value. This value is
     * replaced by its boxed equivalent on top of the stack.
     * 
     * @param type the type of the top stack value.
     */
    public void box(final Type type) {
        if (type.getSort() == Type.OBJECT || type.getSort() == Type.ARRAY) {
            return;
        }
        if (type == Type.VOID_TYPE) {
            push((String) null);
        } else {
            Type boxed = type;
            switch (type.getSort()) {
                case Type.BYTE:
                    boxed = BYTE_TYPE;
                    break;
                case Type.BOOLEAN:
                    boxed = BOOLEAN_TYPE;
                    break;
                case Type.SHORT:
                    boxed = SHORT_TYPE;
                    break;
                case Type.CHAR:
                    boxed = CHARACTER_TYPE;
                    break;
                case Type.INT:
                    boxed = INTEGER_TYPE;
                    break;
                case Type.FLOAT:
                    boxed = FLOAT_TYPE;
                    break;
                case Type.LONG:
                    boxed = LONG_TYPE;
                    break;
                case Type.DOUBLE:
                    boxed = DOUBLE_TYPE;
                    break;
            }
            newInstance(boxed);
            if (type.getSize() == 2) {
                // Pp -> Ppo -> oPpo -> ooPpo -> ooPp -> o
                dupX2();
                dupX2();
                pop();
            } else {
                // p -> po -> opo -> oop -> o
                dupX1();
                swap();
            }
            invokeConstructor(boxed, new Method("<init>",
                    Type.VOID_TYPE,
                    new Type[] { type }));
        }
    }

    /**
     * Generates the instructions to unbox the top stack value. This value is
     * replaced by its unboxed equivalent on top of the stack.
     * 
     * @param type the type of the top stack value.
     */
    public void unbox(final Type type) {
        Type t = NUMBER_TYPE;
        Method sig = null;
        switch (type.getSort()) {
            case Type.VOID:
                return;
            case Type.CHAR:
                t = CHARACTER_TYPE;
                sig = CHAR_VALUE;
                break;
            case Type.BOOLEAN:
                t = BOOLEAN_TYPE;
                sig = BOOLEAN_VALUE;
                break;
            case Type.DOUBLE:
                sig = DOUBLE_VALUE;
                break;
            case Type.FLOAT:
                sig = FLOAT_VALUE;
                break;
            case Type.LONG:
                sig = LONG_VALUE;
                break;
            case Type.INT:
            case Type.SHORT:
            case Type.BYTE:
                sig = INT_VALUE;
        }
        if (sig == null) {
            checkCast(type);
        } else {
            checkCast(t);
            invokeVirtual(t, sig);
        }
    }

    // ------------------------------------------------------------------------
    // Instructions to jump to other instructions
    // ------------------------------------------------------------------------

    /**
     * Creates a new {@link Label}.
     * 
     * @return a new {@link Label}.
     */
    public Label newLabel() {
        return new Label();
    }

    /**
     * Marks the current code position with the given label.
     * 
     * @param label a label.
     */
    public void mark(final Label label) {
        mv.visitLabel(label);
    }

    /**
     * Marks the current code position with a new label.
     * 
     * @return the label that was created to mark the current code position.
     */
    public Label mark() {
        Label label = new Label();
        mv.visitLabel(label);
        return label;
    }

    /**
     * Generates the instructions to jump to a label based on the comparison of
     * the top two stack values.
     * 
     * @param type the type of the top two stack values.
     * @param mode how these values must be compared. One of EQ, NE, LT, GE, GT,
     *        LE.
     * @param label where to jump if the comparison result is <tt>true</tt>.
     */
    public void ifCmp(final Type type, final int mode, final Label label) {
        int intOp = -1;
        switch (type.getSort()) {
            case Type.LONG:
                mv.visitInsn(Opcodes.LCMP);
                break;
            case Type.DOUBLE:
                mv.visitInsn(Opcodes.DCMPG);
                break;
            case Type.FLOAT:
                mv.visitInsn(Opcodes.FCMPG);
                break;
            case Type.ARRAY:
            case Type.OBJECT:
                switch (mode) {
                    case EQ:
                        mv.visitJumpInsn(Opcodes.IF_ACMPEQ, label);
                        return;
                    case NE:
                        mv.visitJumpInsn(Opcodes.IF_ACMPNE, label);
                        return;
                }
                throw new IllegalArgumentException("Bad comparison for type "
                        + type);
            default:
                switch (mode) {
                    case EQ:
                        intOp = Opcodes.IF_ICMPEQ;
                        break;
                    case NE:
                        intOp = Opcodes.IF_ICMPNE;
                        break;
                    case GE:
                        intOp = Opcodes.IF_ICMPGE;
                        break;
                    case LT:
                        intOp = Opcodes.IF_ICMPLT;
                        break;
                    case LE:
                        intOp = Opcodes.IF_ICMPLE;
                        break;
                    case GT:
                        intOp = Opcodes.IF_ICMPGT;
                        break;
                }
                mv.visitJumpInsn(intOp, label);
                return;
        }
        int jumpMode = mode;
        switch (mode) {
            case GE:
                jumpMode = LT;
                break;
            case LE:
                jumpMode = GT;
                break;
        }
        mv.visitJumpInsn(jumpMode, label);
    }

    /**
     * Generates the instructions to jump to a label based on the comparison of
     * the top two integer stack values.
     * 
     * @param mode how these values must be compared. One of EQ, NE, LT, GE, GT,
     *        LE.
     * @param label where to jump if the comparison result is <tt>true</tt>.
     */
    public void ifICmp(final int mode, final Label label) {
        ifCmp(Type.INT_TYPE, mode, label);
    }

    /**
     * Generates the instructions to jump to a label based on the comparison of
     * the top integer stack value with zero.
     * 
     * @param mode how these values must be compared. One of EQ, NE, LT, GE, GT,
     *        LE.
     * @param label where to jump if the comparison result is <tt>true</tt>.
     */
    public void ifZCmp(final int mode, final Label label) {
        mv.visitJumpInsn(mode, label);
    }

    /**
     * Generates the instruction to jump to the given label if the top stack
     * value is null.
     * 
     * @param label where to jump if the condition is <tt>true</tt>.
     */
    public void ifNull(final Label label) {
        mv.visitJumpInsn(Opcodes.IFNULL, label);
    }

    /**
     * Generates the instruction to jump to the given label if the top stack
     * value is not null.
     * 
     * @param label where to jump if the condition is <tt>true</tt>.
     */
    public void ifNonNull(final Label label) {
        mv.visitJumpInsn(Opcodes.IFNONNULL, label);
    }

    /**
     * Generates the instruction to jump to the given label.
     * 
     * @param label where to jump if the condition is <tt>true</tt>.
     */
    public void goTo(final Label label) {
        mv.visitJumpInsn(Opcodes.GOTO, label);
    }

    /**
     * Generates a RET instruction.
     * 
     * @param local a local variable identifier, as returned by
     *        {@link LocalVariablesSorter#newLocal(Type) newLocal()}.
     */
    public void ret(final int local) {
        mv.visitVarInsn(Opcodes.RET, local);
    }

    /**
     * Generates the instructions for a switch statement.
     * 
     * @param keys the switch case keys.
     * @param generator a generator to generate the code for the switch cases.
     */
    public void tableSwitch(
        final int[] keys,
        final TableSwitchGenerator generator)
    {
        float density;
        if (keys.length == 0) {
            density = 0;
        } else {
            density = (float) keys.length
                    / (keys[keys.length - 1] - keys[0] + 1);
        }
        tableSwitch(keys, generator, density >= 0.5f);
    }

    /**
     * Generates the instructions for a switch statement.
     * 
     * @param keys the switch case keys.
     * @param generator a generator to generate the code for the switch cases.
     * @param useTable <tt>true</tt> to use a TABLESWITCH instruction, or
     *        <tt>false</tt> to use a LOOKUPSWITCH instruction.
     */
    public void tableSwitch(
        final int[] keys,