/**
* Perform scalar replacement actions for a Def of a heap variable. NOTE: Even loads can def a
* heap variable.
*
* @param UseRepSet stores the uses(loads) that have been eliminated
* @param registers mapping from valueNumber -> temporary register
*/
static void replaceDefs(IR ir, UseRecordSet UseRepSet, HashMap<UseRecord, Register> registers) {
SSADictionary ssa = ir.HIRInfo.dictionary;
for (Enumeration<Instruction> e = ir.forwardInstrEnumerator(); e.hasMoreElements(); ) {
Instruction s = e.nextElement();
if (!GetField.conforms(s)
&& !GetStatic.conforms(s)
&& !PutField.conforms(s)
&& !PutStatic.conforms(s)
&& !ALoad.conforms(s)
&& !AStore.conforms(s)) {
continue;
}
if (!ssa.defsHeapVariable(s)) {
continue;
}
// this instruction is a DEF of heap variable H.
// Check if UseRepSet needs the scalar assigned by this def
HeapOperand<?>[] H = ssa.getHeapDefs(s);
if (H.length != 1) {
throw new OptimizingCompilerException(
"LoadElimination: encountered a store with more than one def? " + s);
}
int valueNumber = -1;
Object index = null;
if (AStore.conforms(s)) {
Object address = AStore.getArray(s);
index = AStore.getIndex(s);
valueNumber = ir.HIRInfo.valueNumbers.getValueNumber(address);
} else if (GetField.conforms(s)) {
Object address = GetField.getRef(s);
valueNumber = ir.HIRInfo.valueNumbers.getValueNumber(address);
} else if (PutField.conforms(s)) {
Object address = PutField.getRef(s);
valueNumber = ir.HIRInfo.valueNumbers.getValueNumber(address);
} else if (GetStatic.conforms(s)) {
valueNumber = 0;
} else if (PutStatic.conforms(s)) {
valueNumber = 0;
} else if (ALoad.conforms(s)) {
Object address = ALoad.getArray(s);
valueNumber = ir.HIRInfo.valueNumbers.getValueNumber(address);
index = ALoad.getIndex(s);
}
if (index == null) {
// Load/Store
if (UseRepSet.containsMatchingUse(H[0].getHeapVariable(), valueNumber)) {
Operand value = null;
if (PutField.conforms(s)) {
value = PutField.getValue(s);
} else if (PutStatic.conforms(s)) {
value = PutStatic.getValue(s);
} else if (GetField.conforms(s) || GetStatic.conforms(s)) {
value = ResultCarrier.getResult(s);
}
TypeReference type = value.getType();
Register r =
findOrCreateRegister(H[0].getHeapType(), valueNumber, registers, ir.regpool, type);
appendMove(r, value, s);
}
} else {
// ALoad / AStore
int v1 = valueNumber;
int v2 = ir.HIRInfo.valueNumbers.getValueNumber(index);
if (UseRepSet.containsMatchingUse(H[0].getHeapVariable(), v1, v2)) {
Operand value = null;
if (AStore.conforms(s)) {
value = AStore.getValue(s);
} else if (ALoad.conforms(s)) {
value = ALoad.getResult(s);
}
TypeReference type = value.getType();
Register r =
findOrCreateRegister(H[0].getHeapType(), v1, v2, registers, ir.regpool, type);
appendMove(r, value, s);
}
}
}
}
/**
* Update the value graph to account for a given PUTFIELD instruction.
*
* <p><b>PRECONDITION:</b> <code> PutField.conforms(s); </code> Make sure we have value graph
* nodes for a constant value
*
* @param s the instruction in question
*/
private void processPutField(Instruction s) {
Operand value = PutField.getValue(s);
if (value.isConstant()) {
findOrCreateVertex((ConstantOperand) value);
}
}