/**
* Creates a Frame instance to emulate and verify the execution of a single class file method.
*
* @param codeParser the parser used to parse the "Code" attribute of the method being emulated
* @param extraLocals the number of extra local variables needed
*/
public Frame(CodeParser codeParser, int extraLocals) {
this.maxStack = codeParser.getMaxStack();
this.codeParser = codeParser;
/*
* Initialize the operand stack
*/
stack = new StackProducer[maxStack];
/*
* Initialize the types in the local variables
*/
localTypes = new Klass[codeParser.getMaxLocals() + extraLocals];
Method method = codeParser.getMethod();
Klass[] parameterTypes = method.getParameterTypes();
Local[] parameterLocals = null;
if (Translator.REVERSE_PARAMETERS && method.isInterpreterInvoked()) {
parameterLocals = new Local[parameterTypes.length];
}
int javacIndex = 0;
/*
* Initialize 'this' in non-static methods. The type of 'this' is
* UNINITIALIZED_THIS if this method is a constructor in any class
* except java.lang.Object otherwise it is the class in which the
* method was defined.
*/
if (!method.isStatic() || method.isConstructor()) {
Assert.that(parameterLocals == null);
Klass thisType = method.getDefiningClass();
if (method.isConstructor() && thisType != Klass.OBJECT) {
thisType = Klass.UNINITIALIZED_THIS;
}
Local thisLocal = allocateParameter(thisType, javacIndex);
store(javacIndex, thisType, thisLocal);
javacIndex++;
}
/*
* Initialize locals for the parameters.
*/
int parameterIndex = javacIndex;
for (int i = 0; i < parameterTypes.length; i++) {
Klass parameterType = parameterTypes[i];
Local parameterLocal = allocateParameter(parameterType, javacIndex);
if (parameterLocals != null) {
parameterLocals[i] = parameterLocal;
}
if (Klass.SQUAWK_64) {
if (javacIndex != parameterIndex) {
Assert.that(parameterIndex < javacIndex);
parameterLocal.setParameterIndex(parameterIndex);
}
parameterIndex++;
}
store(javacIndex, parameterType, parameterLocal);
javacIndex += (parameterType.isDoubleWord() ? 2 : 1);
}
parameterLocalsCount = javacIndex;
/*
* Adjust the parameter offsets for parameter order reversal.
*/
if (parameterLocals != null) {
parameterIndex = 0;
for (int i = parameterTypes.length - 1; i >= 0; i--) {
Klass parameterType = parameterTypes[i];
parameterLocals[i].setParameterIndex(parameterIndex++);
if (!Klass.SQUAWK_64 && parameterType.isDoubleWord()) {
parameterIndex++;
}
}
}
/*
* Initialize the remaining local variables to the TOP type
*/
while (javacIndex < localTypes.length) {
localTypes[javacIndex++] = Klass.TOP;
}
}
