Java 类org.apache.bcel.generic.IFNONNULL 实例源码

private boolean hasManyPreceedingNullTests(int pc) {
    int ifNullTests = 0;
    BitSet seen = new BitSet();
    try {
        for (Iterator<Location> i = classContext.getCFG(method).locationIterator(); i.hasNext();) {
            Location loc = i.next();
            int pc2 = loc.getHandle().getPosition();
            if (pc2 >= pc || pc2 < pc - 30)
                continue;
            Instruction ins = loc.getHandle().getInstruction();
            if ((ins instanceof IFNONNULL || ins instanceof IFNULL || ins instanceof NullnessConversationInstruction)
                    && !seen.get(pc2)) {
                ifNullTests++;
                seen.set(pc2);
            }
        }
        boolean result = ifNullTests > 2;

        // System.out.println("Preceeding null tests " + ifNullTests + " " +
        // ifNonnullTests + " " + result);
        return result;
    } catch (CFGBuilderException e) {
        return false;
    }
}

private boolean hasManyPreceedingNullTests(int pc) {
    int ifNullTests = 0;
    BitSet seen = new BitSet();
    try {
        for (Iterator<Location> i = classContext.getCFG(method).locationIterator(); i.hasNext();) {
            Location loc = i.next();
            int pc2 = loc.getHandle().getPosition();
            if (pc2 >= pc || pc2 < pc - 30)
                continue;
            Instruction ins = loc.getHandle().getInstruction();
            if ((ins instanceof IFNONNULL || ins instanceof IFNULL || ins instanceof NullnessConversationInstruction)
                    && !seen.get(pc2)) {
                ifNullTests++;
                seen.set(pc2);
            }
        }
        boolean result = ifNullTests > 2;

        // System.out.println("Preceeding null tests " + ifNullTests + " " +
        // ifNonnullTests + " " + result);
        return result;
    } catch (CFGBuilderException e) {
        return false;
    }
}

public static boolean isNullCheck(InstructionHandle h, ConstantPoolGen cpg) {
    if (!(h.getInstruction() instanceof IFNONNULL))
        return false;
    h = h.getNext();
    final Instruction newInstruction = h.getInstruction();
    if (!(newInstruction instanceof NEW))
        return false;
    final ObjectType loadClassType = ((NEW) newInstruction).getLoadClassType(cpg);
    if (!loadClassType.getClassName().equals("java.lang.NullPointerException"))
        return false;
    h = h.getNext();
    return check(h, NULLCHECK1) || check(h, NULLCHECK2);

}

@Override
public MatchResult match(InstructionHandle handle, ConstantPoolGen cpg, ValueNumberFrame before, ValueNumberFrame after,
        BindingSet bindingSet) throws DataflowAnalysisException {

    // Instruction must be IFNULL or IFNONNULL.
    Instruction ins = handle.getInstruction();
    if (!(ins instanceof IFNULL || ins instanceof IFNONNULL))
        return null;

    // Ensure reference used is consistent with previous uses of
    // same variable.
    LocalVariable ref = new LocalVariable(before.getTopValue());
    return addOrCheckDefinition(ref, bindingSet);
}

public static boolean isNullCheck(InstructionHandle h, ConstantPoolGen cpg) {
    if (!(h.getInstruction() instanceof IFNONNULL))
        return false;
    h = h.getNext();
    final Instruction newInstruction = h.getInstruction();
    if (!(newInstruction instanceof NEW))
        return false;
    final ObjectType loadClassType = ((NEW) newInstruction).getLoadClassType(cpg);
    if (!loadClassType.getClassName().equals("java.lang.NullPointerException"))
        return false;
    h = h.getNext();
    return check(h, NULLCHECK1) || check(h, NULLCHECK2);

}

@Override
public MatchResult match(InstructionHandle handle, ConstantPoolGen cpg, ValueNumberFrame before, ValueNumberFrame after,
        BindingSet bindingSet) throws DataflowAnalysisException {

    // Instruction must be IFNULL or IFNONNULL.
    Instruction ins = handle.getInstruction();
    if (!(ins instanceof IFNULL || ins instanceof IFNONNULL))
        return null;

    // Ensure reference used is consistent with previous uses of
    // same variable.
    LocalVariable ref = new LocalVariable(before.getTopValue());
    return addOrCheckDefinition(ref, bindingSet);
}

private void generateMethods(RootClass k, ConstantPoolGen cp, InstructionList il, InstructionFactory factory, ClassGen cg, String className)
{
   RootMember[] members = k.getMembers();
   for (int i = 0; i < members.length; i++)
   {
      BasicMember member = (BasicMember) members[i];
      TLeaf leaf = (TLeaf) lMap.get(member);
      if (leaf == null) continue;
      String leafClassName = leaf.getClass().getName();

      Type type = member.getJavaType();
      Type arrayType = new ArrayType(type, 1);
      MethodGen mg = new MethodGen(ACC_PUBLIC, type, new Type[] { Type.INT }, new String[]
         {
            "index"
         }, nameMangler.mangleMember(member.getName()), className, il, cp);
      il.append(InstructionConstants.ALOAD_0);
      il.append(factory.createGetField(className, member.getName(), arrayType));
      il.append(InstructionFactory.DUP);

      BranchHandle bh = il.append(new IFNONNULL(null));
      il.append(InstructionFactory.POP);
      il.append(factory.createGetStatic(className, member.getName() + "Leaf", new ObjectType(leafClassName)));
      il.append(InstructionConstants.ALOAD_0);
      il.append(factory.createGetField("org.dianahep.root4j.core.Clones2", "hollowIndex", Type.LONG));

      //    BasicRootClass varClass = (BasicRootClass) member.getType();
      il.append(factory.createInvoke(leafClassName, "setPosition", new ObjectType("org.dianahep.root4j.core.RootInput"), new Type[]
            {
               Type.LONG
            }, INVOKEVIRTUAL));
      il.append(InstructionConstants.ALOAD_0);
      il.append(factory.createGetField("org.dianahep.root4j.core.Clones2", "size", Type.INT));
      il.append((Instruction) factory.createNewArray(type, (short) 1));
      il.append(InstructionConstants.DUP_X1);
      il.append(factory.createInvoke("org.dianahep.root4j.core.RootInput", "readFixedArray", Type.VOID, new Type[]
            {
               arrayType
            }, INVOKEINTERFACE));

      il.append(InstructionConstants.DUP);
      il.append(InstructionConstants.ALOAD_0);
      il.append(InstructionConstants.SWAP);
      il.append(factory.createPutField(className, member.getName(), arrayType));

      bh.setTarget(il.append(InstructionConstants.ILOAD_1));
      il.append(InstructionFactory.createArrayLoad(type));
      il.append(InstructionFactory.createReturn(type));
      mg.setMaxStack();
      mg.setMaxLocals();
      cg.addMethod(mg.getMethod());
      il.dispose();
   }
}