/**
* Get a <code>Local</code> instance to represent a value of a given type that will be
* stored/loaded to/from a given local variable.
*
* @param type the type of the value
* @param index the index of the local variable
* @param isParameter true if the local is a parameter
* @return the variable at index <code>index</code> in which values of type <code>type</code> are
* stored
*/
private Local allocateLocalPrim(Klass type, int index, boolean isParameter) {
Assert.that(localTypes.length < 0xFFFF);
Assert.that(
index >= 0 && index < localTypes.length,
"index=" + index + " localTypes.length=" + localTypes.length);
Klass localType = getLocalTypeFor(type);
int key = localType.getSuiteID();
/* We need a hard partition between uses of a slot as a reference vs. an Address, Offset, or UWord.
* The partitioning of java primitives and objects is accomplished not only by the type passed in here, but
* by the bytecode verifier. We can't be sure that some bytecodes are refering to the same local variable
* as both a reference and as a Squawk primitive. Without that kind of support we are conservative here
* and force a clash whenever javac uses the same local index for a reference and a Squawk primitive.
*/
if (localType.isSquawkPrimitive()) {
key = Klass.REFERENCE.getSuiteID();
}
key = key << 16 | index;
if (localValues == null) {
localValues = new IntHashtable();
}
Local local = (Local) localValues.get(key);
if (local == null) {
local = new Local(localType, index, isParameter);
localValues.put(key, local);
}
/*
* Ensure that the original class file does not use the same local variable
* for both a Squawk primitive value and any other reference value. This prevents the
* translator from having to do a complete liveness analysis to de-multiplex
* such a local variable slot. Such de-multiplexing is required as Squawk primitives
* are 'magically' translated into integers (or longs on a 64 bit system).
*/
if (localType.isSquawkPrimitive() || local.getType().isSquawkPrimitive()) {
if (localType != local.getType()) {
throw codeParser.verifyError(
getBadAddressLocalVariableMessage(index, localType, local.getType()));
}
}
// System.out.println("allocated: "+local+" index "+index);
/// *if[SCOPEDLOCALVARIABLES]*/
codeParser.localVariableAllocated(codeParser.getCurrentIP(), local);
/// *end[SCOPEDLOCALVARIABLES]*/
return local;
}
/**
* Emulates the storing of a value to a local variable.
*
* @param index the index of the local variable being stored to
* @param type the type of the value
* @param local the variable to which the value is stored
*/
public void store(int index, Klass type, Local local) {
Klass localType = local.getType();
Assert.that(localType.isAssignableFrom(type) || localType == getLocalTypeFor(type));
verifyLocalVariableIndex(localType, index);
localTypes[index] = type;
if (localType.isDoubleWord()) {
localTypes[index + 1] = Klass.getSecondWordType(localType);
} else {
verifyUseOfSquawkPrimitive(localType, type);
}
}
/**
* 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;
}
}
