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Frame.javaAPI DocGlassfish v2 API21851Thu Mar 02 11:51:18 GMT 2006oracle.toplink.libraries.asm.tree.analysis

Frame

public class Frame extends Object
A symbolic execution stack frame. A stack frame contains a set of local variable slots, and an operand stack. Warning: long and double values are represented by two slots in local variables, and by one slot in the operand stack.
author
Eric Bruneton

Fields Summary
private Value[]
locals
The local variables of this frame.
private Value[]
stack
The operand stack of this frame.
private int
top
The number of elements in the operand stack.
Constructors Summary
public Frame(int nLocals, int nStack)
Constructs a new frame with the given size.

param
nLocals the maximum number of local variables of the frame.
param
nStack the maximum stack size of the frame.

    this.locals = new Value[nLocals];
    this.stack = new Value[nStack];
public Frame(Frame src)
Constructs a new frame that is identical to the given frame.

param
src a frame.

    this(src.locals.length, src.stack.length);
    init(src);
Methods Summary
public voidclearStack()
Clears the operand stack of this frame.

    top = 0;
public voidexecute(oracle.toplink.libraries.asm.tree.AbstractInsnNode insn, Interpreter interpreter)

    Value value1, value2, value3, value4;
    List values;
    int var;
    
    switch (insn.getOpcode()) {
      case Constants.NOP:
        break;
      case Constants.ACONST_NULL:
      case Constants.ICONST_M1:
      case Constants.ICONST_0:
      case Constants.ICONST_1:
      case Constants.ICONST_2:
      case Constants.ICONST_3:
      case Constants.ICONST_4:
      case Constants.ICONST_5:
      case Constants.LCONST_0:
      case Constants.LCONST_1:
      case Constants.FCONST_0:
      case Constants.FCONST_1:
      case Constants.FCONST_2:
      case Constants.DCONST_0:
      case Constants.DCONST_1:
      case Constants.BIPUSH:
      case Constants.SIPUSH:
      case Constants.LDC:
        push(interpreter.newOperation(insn));
        break;
      case Constants.ILOAD:
      case Constants.LLOAD:
      case Constants.FLOAD:
      case Constants.DLOAD:
      case Constants.ALOAD:
        push(interpreter.copyOperation(insn, getLocal(((VarInsnNode)insn).var)));
        break;
      case Constants.IALOAD:
      case Constants.LALOAD:
      case Constants.FALOAD:
      case Constants.DALOAD:
      case Constants.AALOAD:
      case Constants.BALOAD:
      case Constants.CALOAD:
      case Constants.SALOAD:
        value2 = pop();
        value1 = pop();
        push(interpreter.binaryOperation(insn, value1, value2));
        break;
      case Constants.ISTORE:
      case Constants.LSTORE:
      case Constants.FSTORE:
      case Constants.DSTORE:
      case Constants.ASTORE:
        value1 = interpreter.copyOperation(insn, pop());
        var = ((VarInsnNode)insn).var;
        setLocal(var, value1);
        if (value1.getSize() == 2) {
          setLocal(var + 1, interpreter.newValue(null));
        }
        if (var > 0 && getLocal(var - 1).getSize() == 2) {
          setLocal(var - 1, interpreter.newValue(null));
        }
        break;
      case Constants.IASTORE:
      case Constants.LASTORE:
      case Constants.FASTORE:
      case Constants.DASTORE:
      case Constants.AASTORE:
      case Constants.BASTORE:
      case Constants.CASTORE:
      case Constants.SASTORE:
        value3 = pop();
        value2 = pop();
        value1 = pop();
        interpreter.ternaryOperation(insn, value1, value2, value3);
        break;
      case Constants.POP:
        if (pop().getSize() == 2) {
          throw new AnalyzerException("Illegal use of POP");
        }
        break;
      case Constants.POP2:
        if (pop().getSize() == 1) {
          if (pop().getSize() != 1) {
            throw new AnalyzerException("Illegal use of POP2");
          }
        }
        break;
      case Constants.DUP:
        value1 = pop();
        if (value1.getSize() != 1) {
          throw new AnalyzerException("Illegal use of DUP");
        }
        push(interpreter.copyOperation(insn, value1));
        push(interpreter.copyOperation(insn, value1));
        break;
      case Constants.DUP_X1:
        value1 = pop();
        value2 = pop();
        if (value1.getSize() != 1 || value2.getSize() != 1) {
          throw new AnalyzerException("Illegal use of DUP_X1");
        }
        push(interpreter.copyOperation(insn, value1));
        push(interpreter.copyOperation(insn, value2));
        push(interpreter.copyOperation(insn, value1));
        break;
      case Constants.DUP_X2:
        value1 = pop();
        if (value1.getSize() == 1) {
          value2 = pop();
          if (value2.getSize() == 1) {
            value3 = pop();
            if (value3.getSize() == 1) {
              push(interpreter.copyOperation(insn, value1));
              push(interpreter.copyOperation(insn, value3));
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              break;
            }
          } else {
            push(interpreter.copyOperation(insn, value1));
            push(interpreter.copyOperation(insn, value2));
            push(interpreter.copyOperation(insn, value1));
            break;
          }
        }
        throw new AnalyzerException("Illegal use of DUP_X2");
      case Constants.DUP2:
        value1 = pop();
        if (value1.getSize() == 1) {
          value2 = pop();
          if (value2.getSize() == 1) {
            push(interpreter.copyOperation(insn, value2));
            push(interpreter.copyOperation(insn, value1));
            push(interpreter.copyOperation(insn, value2));
            push(interpreter.copyOperation(insn, value1));
            break;
          }
        } else {
          push(interpreter.copyOperation(insn, value1));
          push(interpreter.copyOperation(insn, value1));
          break;
        }
        throw new AnalyzerException("Illegal use of DUP2");
      case Constants.DUP2_X1:
        value1 = pop();
        if (value1.getSize() == 1) {
          value2 = pop();
          if (value2.getSize() == 1) {
            value3 = pop();
            if (value3.getSize() == 1) {
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              push(interpreter.copyOperation(insn, value3));
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              break;
            }
          }
        } else {
          value2 = pop();
          if (value2.getSize() == 1) {
            push(interpreter.copyOperation(insn, value1));
            push(interpreter.copyOperation(insn, value2));
            push(interpreter.copyOperation(insn, value1));
            break;
          }
        }
        throw new AnalyzerException("Illegal use of DUP2_X1");
      case Constants.DUP2_X2:
        value1 = pop();
        if (value1.getSize() == 1) {
          value2 = pop();
          if (value2.getSize() == 1) {
            value3 = pop();
            if (value3.getSize() == 1) {
              value4 = pop();
              if (value4.getSize() == 1) {
                push(interpreter.copyOperation(insn, value2));
                push(interpreter.copyOperation(insn, value1));
                push(interpreter.copyOperation(insn, value4));
                push(interpreter.copyOperation(insn, value3));
                push(interpreter.copyOperation(insn, value2));
                push(interpreter.copyOperation(insn, value1));
                break;
              }
            } else {
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              push(interpreter.copyOperation(insn, value3));
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              break;
            }
          }
        } else {
          value2 = pop();
          if (value2.getSize() == 1) {
            value3 = pop();
            if (value3.getSize() == 1) {
              push(interpreter.copyOperation(insn, value1));
              push(interpreter.copyOperation(insn, value3));
              push(interpreter.copyOperation(insn, value2));
              push(interpreter.copyOperation(insn, value1));
              break;
            }
          } else {
            push(interpreter.copyOperation(insn, value1));
            push(interpreter.copyOperation(insn, value2));
            push(interpreter.copyOperation(insn, value1));
            break;
          }
        }
        throw new AnalyzerException("Illegal use of DUP2_X2");
      case Constants.SWAP:
        value2 = pop();
        value1 = pop();
        if (value1.getSize() != 1 || value2.getSize() != 1) {
          throw new AnalyzerException("Illegal use of SWAP");
        }
        push(interpreter.copyOperation(insn, value2));
        push(interpreter.copyOperation(insn, value1));
        break;
      case Constants.IADD:
      case Constants.LADD:
      case Constants.FADD:
      case Constants.DADD:
      case Constants.ISUB:
      case Constants.LSUB:
      case Constants.FSUB:
      case Constants.DSUB:
      case Constants.IMUL:
      case Constants.LMUL:
      case Constants.FMUL:
      case Constants.DMUL:
      case Constants.IDIV:
      case Constants.LDIV:
      case Constants.FDIV:
      case Constants.DDIV:
      case Constants.IREM:
      case Constants.LREM:
      case Constants.FREM:
      case Constants.DREM:
        value2 = pop();
        value1 = pop();
        push(interpreter.binaryOperation(insn, value1, value2));
        break;
      case Constants.INEG:
      case Constants.LNEG:
      case Constants.FNEG:
      case Constants.DNEG:
        push(interpreter.unaryOperation(insn, pop()));
        break;
      case Constants.ISHL:
      case Constants.LSHL:
      case Constants.ISHR:
      case Constants.LSHR:
      case Constants.IUSHR:
      case Constants.LUSHR:
      case Constants.IAND:
      case Constants.LAND:
      case Constants.IOR:
      case Constants.LOR:
      case Constants.IXOR:
      case Constants.LXOR:
        value2 = pop();
        value1 = pop();
        push(interpreter.binaryOperation(insn, value1, value2));
        break;
      case Constants.IINC:
        var = ((IincInsnNode)insn).var;
        setLocal(var, interpreter.unaryOperation(insn, getLocal(var)));
        break;
      case Constants.I2L:
      case Constants.I2F:
      case Constants.I2D:
      case Constants.L2I:
      case Constants.L2F:
      case Constants.L2D:
      case Constants.F2I:
      case Constants.F2L:
      case Constants.F2D:
      case Constants.D2I:
      case Constants.D2L:
      case Constants.D2F:
      case Constants.I2B:
      case Constants.I2C:
      case Constants.I2S:
        push(interpreter.unaryOperation(insn, pop()));
        break;
      case Constants.LCMP:
      case Constants.FCMPL:
      case Constants.FCMPG:
      case Constants.DCMPL:
      case Constants.DCMPG:
        value2 = pop();
        value1 = pop();
        push(interpreter.binaryOperation(insn, value1, value2));
        break;
      case Constants.IFEQ:
      case Constants.IFNE:
      case Constants.IFLT:
      case Constants.IFGE:
      case Constants.IFGT:
      case Constants.IFLE:
        interpreter.unaryOperation(insn, pop());
        break;
      case Constants.IF_ICMPEQ:
      case Constants.IF_ICMPNE:
      case Constants.IF_ICMPLT:
      case Constants.IF_ICMPGE:
      case Constants.IF_ICMPGT:
      case Constants.IF_ICMPLE:
      case Constants.IF_ACMPEQ:
      case Constants.IF_ACMPNE:
        value2 = pop();
        value1 = pop();
        interpreter.binaryOperation(insn, value1, value2);
        break;
      case Constants.GOTO:
        break;
      case Constants.JSR:
        push(interpreter.newOperation(insn));
        break;
      case Constants.RET:
        break;
      case Constants.TABLESWITCH:
      case Constants.LOOKUPSWITCH:
      case Constants.IRETURN:
      case Constants.LRETURN:
      case Constants.FRETURN:
      case Constants.DRETURN:
      case Constants.ARETURN:
        interpreter.unaryOperation(insn, pop());
        break;
      case Constants.RETURN:
        break;
      case Constants.GETSTATIC:
        push(interpreter.newOperation(insn));
        break;
      case Constants.PUTSTATIC:
        interpreter.unaryOperation(insn, pop());
        break;
      case Constants.GETFIELD:
        push(interpreter.unaryOperation(insn, pop()));
        break;
      case Constants.PUTFIELD:
        value2 = pop();
        value1 = pop();
        interpreter.binaryOperation(insn, value1, value2);
        break;
      case Constants.INVOKEVIRTUAL:
      case Constants.INVOKESPECIAL:
      case Constants.INVOKESTATIC:
      case Constants.INVOKEINTERFACE:
        values = new ArrayList();
        String desc = ((MethodInsnNode)insn).desc;
        for (int i = Type.getArgumentTypes(desc).length; i > 0; --i) {
          values.add(0, pop());
        }
        if (insn.getOpcode() != Constants.INVOKESTATIC) {
          values.add(0, pop());
        }
        if (Type.getReturnType(desc) == Type.VOID_TYPE) {
          interpreter.naryOperation(insn, values);
        } else {
          push(interpreter.naryOperation(insn, values));
        }
        break;
      case Constants.NEW:
        push(interpreter.newOperation(insn));
        break;
      case Constants.NEWARRAY:
      case Constants.ANEWARRAY:
      case Constants.ARRAYLENGTH:
        push(interpreter.unaryOperation(insn, pop()));
        break;
      case Constants.ATHROW:
        interpreter.unaryOperation(insn, pop());
        break;
      case Constants.CHECKCAST:
      case Constants.INSTANCEOF:
        push(interpreter.unaryOperation(insn, pop()));
        break;
      case Constants.MONITORENTER:
      case Constants.MONITOREXIT:
        interpreter.unaryOperation(insn, pop());
        break;
      case Constants.MULTIANEWARRAY:
        values = new ArrayList();
        for (int i = ((MultiANewArrayInsnNode)insn).dims; i > 0; --i) {
          values.add(0, pop());
        }
        push(interpreter.naryOperation(insn, values));
        break;
      case Constants.IFNULL:
      case Constants.IFNONNULL:
        interpreter.unaryOperation(insn, pop());
        break;
      default:
        throw new RuntimeException("Illegal opcode");
    }
public ValuegetLocal(int i)
Returns the value of the given local variable.

param
i a local variable index.
return
the value of the given local variable.
throws
AnalyzerException if the variable does not exist.

    if (i >= locals.length) {
      throw new AnalyzerException("Trying to access an inexistant local variable");
    }
    return locals[i];
public intgetLocals()
Returns the maximum number of local variables of this frame.

return
the maximum number of local variables of this frame.

    return locals.length;
public ValuegetStack(int i)
Returns the value of the given operand stack slot.

param
i the index of an operand stack slot.
return
the value of the given operand stack slot.
throws
AnalyzerException if the operand stack slot does not exist.

    if (i >= top) {
      throw new AnalyzerException("Trying to access an inexistant stack element");
    }
    return stack[i];
public intgetStackSize()
Returns the number of values in the operand stack of this frame. Long and double values are treated as single values.

return
the number of values in the operand stack of this frame.

    return top;
public oracle.toplink.libraries.asm.tree.analysis.Frameinit(oracle.toplink.libraries.asm.tree.analysis.Frame src)
Copies the state of the given frame into this frame.

param
src a frame.
return
this frame.

    System.arraycopy(src.locals, 0, locals, 0, locals.length);
    System.arraycopy(src.stack, 0, stack, 0, src.top);
    top = src.top;
    return this;
public booleanmerge(oracle.toplink.libraries.asm.tree.analysis.Frame frame, Interpreter interpreter)
Merges this frame with the given frame.

param
frame a frame.
param
interpreter the interpreter used to merge values.
return
true if this frame has been changed as a result of the merge operation, or false otherwise.
throws
AnalyzerException if the frames have incompatible sizes.

    if (top != frame.top) {
      throw new AnalyzerException("Incompatible stack heights");
    }
    boolean changes = false;
    for (int i = 0; i < locals.length; ++i) {
      Value v = interpreter.merge(locals[i], frame.locals[i]);
      if (v != locals[i]) {
        locals[i] = v;
        changes |= true;
      }
    }
    for (int i = 0; i < top; ++i) {
      Value v = interpreter.merge(stack[i], frame.stack[i]);
      if (v != stack[i]) {
        stack[i] = v;
        changes |= true;
      }
    }
    return changes;
public booleanmerge(oracle.toplink.libraries.asm.tree.analysis.Frame frame, boolean[] access)
Merges this frame with the given frame (case of a RET instruction).

param
frame a frame
param
access the local variables that have been accessed by the subroutine to which the RET instruction corresponds.
return
true if this frame has been changed as a result of the merge operation, or false otherwise.

    boolean changes = false;
    for (int i = 0; i < locals.length; ++i) {
      if (!access[i] && !locals[i].equals(frame.locals[i])) {
        locals[i] = frame.locals[i];
        changes = true;
      }
    }
    return changes;
public Valuepop()
Pops a value from the operand stack of this frame.

return
the value that has been popped from the stack.
throws
AnalyzerException if the operand stack is empty.

    if (top == 0) {
      throw new AnalyzerException("Cannot pop operand off an empty stack.");
    }
    return stack[--top];
public voidpush(Value value)
Pushes a value into the operand stack of this frame.

param
value the value that must be pushed into the stack.
throws
AnalyzerException if the operand stack is full.

    if (top >= stack.length) {
      throw new AnalyzerException("Insufficient maximum stack size.");
    }
    stack[top++] = value;
public voidsetLocal(int i, Value value)
Sets the value of the given local variable.

param
i a local variable index.
param
value the new value of this local variable.
throws
AnalyzerException if the variable does not exist.

    if (i >= locals.length) {
      throw new AnalyzerException("Trying to access an inexistant local variable");
    }
    locals[i] = value;
public java.lang.StringtoString()
Returns a string representation of this frame.

return
a string representation of this frame.

    StringBuffer b = new StringBuffer();
    for (int i = 0; i < locals.length; ++i) {
      b.append(locals[i]);
    }
    b.append(' ");
    for (int i = 0; i < top; ++i) {
      b.append(stack[i].toString());
    }
    return b.toString();