analyzeradapter.java

asm的源码包 并且包含英文的文档

/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.objectweb.asm.commons;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.objectweb.asm.Label;
import org.objectweb.asm.MethodAdapter;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;

/**
 * A {@link MethodAdapter} that keeps track of stack map frame changes between
 * {@link #visitFrame(int, int, Object[], int, Object[]) visitFrame} calls. This
 * adapter must be used with the
 * {@link org.objectweb.asm.ClassReader#EXPAND_FRAMES} option. Each visit<i>XXX</i>
 * instruction delegates to the next visitor in the chain, if any, and then
 * simulates the effect of this instruction on the stack map frame, represented
 * by {@link #locals} and {@link #stack}. The next visitor in the chain can get
 * the state of the stack map frame <i>before</i> each instruction by reading
 * the value of these fields in its visit<i>XXX</i> methods (this requires a
 * reference to the AnalyzerAdapter that is before it in the chain).
 * 
 * @author Eric Bruneton
 */
public class AnalyzerAdapter extends MethodAdapter {

    /**
     * <code>List</code> of the local variable slots for current execution
     * frame. Primitive types are represented by {@link Opcodes#TOP},
     * {@link Opcodes#INTEGER}, {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
     * {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
     * {@link Opcodes#UNINITIALIZED_THIS} (long and double are represented by a
     * two elements, the second one being TOP). Reference types are represented
     * by String objects (representing internal names, or type descriptors for
     * array types), and uninitialized types by Label objects (this label
     * designates the NEW instruction that created this uninitialized value).
     * This field is <tt>null</tt> for unreacheable instructions.
     */
    public List locals;

    /**
     * <code>List</code> of the operand stack slots for current execution
     * frame. Primitive types are represented by {@link Opcodes#TOP},
     * {@link Opcodes#INTEGER}, {@link Opcodes#FLOAT}, {@link Opcodes#LONG},
     * {@link Opcodes#DOUBLE},{@link Opcodes#NULL} or
     * {@link Opcodes#UNINITIALIZED_THIS} (long and double are represented by a
     * two elements, the second one being TOP). Reference types are represented
     * by String objects (representing internal names, or type descriptors for
     * array types), and uninitialized types by Label objects (this label
     * designates the NEW instruction that created this uninitialized value).
     * This field is <tt>null</tt> for unreacheable instructions.
     */
    public List stack;

    /**
     * The labels that designate the next instruction to be visited. May be
     * <tt>null</tt>.
     */
    private List labels;

    /**
     * Information about uninitialized types in the current execution frame.
     * This map associates internal names to Label objects. Each label
     * designates a NEW instruction that created the currently uninitialized
     * types, and the associated internal name represents the NEW operand, i.e.
     * the final, initialized type value.
     */
    private Map uninitializedTypes;

    /**
     * The maximum stack size of this method.
     */
    private int maxStack;

    /**
     * The maximum number of local variables of this method.
     */
    private int maxLocals;

    /**
     * Creates a new {@link AnalyzerAdapter}.
     * 
     * @param owner the owner's class name.
     * @param access the method's access flags (see {@link Opcodes}).
     * @param name the method's name.
     * @param desc the method's descriptor (see {@link Type Type}).
     * @param mv the method visitor to which this adapter delegates calls. May
     *        be <tt>null</tt>.
     */
    public AnalyzerAdapter(
        final String owner,
        final int access,
        final String name,
        final String desc,
        final MethodVisitor mv)
    {
        super(mv);
        locals = new ArrayList();
        stack = new ArrayList();
        uninitializedTypes = new HashMap();

        if ((access & Opcodes.ACC_STATIC) == 0) {
            if (name.equals("<init>")) {
                locals.add(Opcodes.UNINITIALIZED_THIS);
            } else {
                locals.add(owner);
            }
        }
        Type[] types = Type.getArgumentTypes(desc);
        for (int i = 0; i < types.length; ++i) {
            Type type = types[i];
            switch (type.getSort()) {
                case Type.BOOLEAN:
                case Type.CHAR:
                case Type.BYTE:
                case Type.SHORT:
                case Type.INT:
                    locals.add(Opcodes.INTEGER);
                    break;
                case Type.FLOAT:
                    locals.add(Opcodes.FLOAT);
                    break;
                case Type.LONG:
                    locals.add(Opcodes.LONG);
                    locals.add(Opcodes.TOP);
                    break;
                case Type.DOUBLE:
                    locals.add(Opcodes.DOUBLE);
                    locals.add(Opcodes.TOP);
                    break;
                case Type.ARRAY:
                    locals.add(types[i].getDescriptor());
                    break;
                // case Type.OBJECT:
                default:
                    locals.add(types[i].getInternalName());
            }
        }
    }

    public void visitFrame(
        final int type,
        final int nLocal,
        final Object[] local,
        final int nStack,
        final Object[] stack)
    {
        if (type != Opcodes.F_NEW) { // uncompressed frame
            throw new IllegalStateException("ClassReader.accept() should be called with EXPAND_FRAMES flag");
        }

        if (mv != null) {
            mv.visitFrame(type, nLocal, local, nStack, stack);
        }

        if (this.locals != null) {
            this.locals.clear();
            this.stack.clear();
        } else {
            this.locals = new ArrayList();
            this.stack = new ArrayList();
        }
        visitFrameTypes(nLocal, local, this.locals);
        visitFrameTypes(nStack, stack, this.stack);
        maxStack = Math.max(maxStack, this.stack.size());
    }

    private void visitFrameTypes(
        final int n,
        final Object[] types,
        final List result)
    {
        for (int i = 0; i < n; ++i) {
            Object type = types[i];
            result.add(type);
            if (type == Opcodes.LONG || type == Opcodes.DOUBLE) {
                result.add(Opcodes.TOP);
            }
        }
    }

    public void visitInsn(final int opcode) {
        if (mv != null) {
            mv.visitInsn(opcode);
        }
        execute(opcode, 0, null);
        if ((opcode >= Opcodes.IRETURN && opcode <= Opcodes.RETURN)
                || opcode == Opcodes.ATHROW)
        {
            this.locals = null;
            this.stack = null;
        }
    }

    public void visitIntInsn(final int opcode, final int operand) {
        if (mv != null) {
            mv.visitIntInsn(opcode, operand);
        }
        execute(opcode, operand, null);
    }

    public void visitVarInsn(final int opcode, final int var) {
        if (mv != null) {
            mv.visitVarInsn(opcode, var);
        }
        execute(opcode, var, null);
    }

    public void visitTypeInsn(final int opcode, final String desc) {
        if (opcode == Opcodes.NEW) {
            if (labels == null) {
                Label l = new Label();
                labels = new ArrayList(3);
                labels.add(l);
                if (mv != null) {
                    mv.visitLabel(l);
                }
            }
            for (int i = 0; i < labels.size(); ++i) {
                uninitializedTypes.put(labels.get(i), desc);
            }
        }
        if (mv != null) {
            mv.visitTypeInsn(opcode, desc);
        }
        execute(opcode, 0, desc);
    }

    public void visitFieldInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        if (mv != null) {
            mv.visitFieldInsn(opcode, owner, name, desc);
        }
        execute(opcode, 0, desc);
    }

    public void visitMethodInsn(
        final int opcode,
        final String owner,
        final String name,
        final String desc)
    {
        if (mv != null) {
            mv.visitMethodInsn(opcode, owner, name, desc);
        }
        pop(desc);
        if (opcode != Opcodes.INVOKESTATIC) {
            Object t = pop();
            if (opcode == Opcodes.INVOKESPECIAL && name.charAt(0) == '<') {
                Object u;
                if (t == Opcodes.UNINITIALIZED_THIS) {
                    u = owner;
                } else {
                    u = uninitializedTypes.get(t);
                }
                for (int i = 0; i < locals.size(); ++i) {
                    if (locals.get(i) == t) {
                        locals.set(i, u);
                    }
                }
                for (int i = 0; i < stack.size(); ++i) {
                    if (stack.get(i) == t) {
                        stack.set(i, u);
                    }
                }
            }
        }
        pushDesc(desc);
        labels = null;
    }

    public void visitJumpInsn(final int opcode, final Label label) {
        if (mv != null) {
            mv.visitJumpInsn(opcode, label);
        }
        execute(opcode, 0, null);
        if (opcode == Opcodes.GOTO) {
            this.locals = null;
            this.stack = null;
        }
    }

    public void visitLabel(final Label label) {
        if (mv != null) {
            mv.visitLabel(label);
        }
        if (labels == null) {
            labels = new ArrayList(3);
        }
        labels.add(label);
    }

    public void visitLdcInsn(final Object cst) {
        if (mv != null) {
            mv.visitLdcInsn(cst);
        }
        if (cst instanceof Integer) {
            push(Opcodes.INTEGER);
        } else if (cst instanceof Long) {
            push(Opcodes.LONG);
            push(Opcodes.TOP);
        } else if (cst instanceof Float) {
            push(Opcodes.FLOAT);
        } else if (cst instanceof Double) {
            push(Opcodes.DOUBLE);
            push(Opcodes.TOP);
        } else if (cst instanceof String) {
            push("java/lang/String");
        } else if (cst instanceof Type) {
            push("java/lang/Class");
        } else {
            throw new IllegalArgumentException();
        }
        labels = null;
    }

    public void visitIincInsn(final int var, final int increment) {
        if (mv != null) {
            mv.visitIincInsn(var, increment);
        }
        execute(Opcodes.IINC, var, null);
    }

    public void visitTableSwitchInsn(
        final int min,
        final int max,
        final Label dflt,
        final Label labels[])
    {
        if (mv != null) {
            mv.visitTableSwitchInsn(min, max, dflt, labels);
        }
        execute(Opcodes.TABLESWITCH, 0, null);
        this.locals = null;
        this.stack = null;
    }

    public void visitLookupSwitchInsn(
        final Label dflt,
        final int keys[],
        final Label labels[])
    {
        if (mv != null) {
            mv.visitLookupSwitchInsn(dflt, keys, labels);
        }
        execute(Opcodes.LOOKUPSWITCH, 0, null);
        this.locals = null;
        this.stack = null;
    }

    public void visitMultiANewArrayInsn(final String desc, final int dims) {
        if (mv != null) {
            mv.visitMultiANewArrayInsn(desc, dims);
        }
        execute(Opcodes.MULTIANEWARRAY, dims, desc);
    }

    public void visitMaxs(final int maxStack, final int maxLocals) {
        if (mv != null) {
            this.maxStack = Math.max(this.maxStack, maxStack);
            this.maxLocals = Math.max(this.maxLocals, maxLocals);
            mv.visitMaxs(this.maxStack, this.maxLocals);
        }
    }

    // ------------------------------------------------------------------------

    private Object get(final int local) {
        maxLocals = Math.max(maxLocals, local);
        return local < locals.size() ? locals.get(local) : Opcodes.TOP;
    }

    private void set(final int local, final Object type) {
        maxLocals = Math.max(maxLocals, local);
        while (local >= locals.size()) {
            locals.add(Opcodes.TOP);
        }
        locals.set(local, type);
    }

    private void push(final Object type) {
        stack.add(type);
        maxStack = Math.max(maxStack, stack.size());
    }

    private void pushDesc(final String desc) {
        int index = desc.charAt(0) == '(' ? desc.indexOf(')') + 1 : 0;
        switch (desc.charAt(index)) {
            case 'V':
                return;
            case 'Z':
            case 'C':
            case 'B':
            case 'S':
            case 'I':
                push(Opcodes.INTEGER);