private BlockDataFlowState generateDFState(CFGBlock block) {
int totalGlobals = this.uniqueGlobals.get(block.getMethodName()).size();
// Get the original inBitSet for this block
BitSet origIn;
if (this.cfgBlocksState.containsKey(block)) {
origIn = this.cfgBlocksState.get(block).getIn();
} else {
origIn = new BitSet(totalGlobals);
origIn.set(0, totalGlobals);
}
// Calculate the in BitSet by taking intersection of predecessors
BlockDataFlowState bFlow = new BlockDataFlowState(totalGlobals);
// If there exist at least one successor, set Out to all True
if (block.getSuccessors().size() > 0) {
bFlow.getOut().set(0, totalGlobals);
}
BitSet out = bFlow.getOut();
for (CFGBlock pred : block.getSuccessors()) {
if (this.cfgBlocksState.containsKey(pred)) {
out.and(this.cfgBlocksState.get(pred).getIn());
}
}
calculateGenKillSets(block, bFlow);
// Calculate Out
BitSet in = bFlow.getIn(); // IN = (OUT - KILL) U GEN
in.or(out);
in.xor(bFlow.getKill());
in.or(bFlow.getGen());
if (!in.equals(origIn)) {
// Add successors to cfgBlocks list
for (CFGBlock pred : block.getPredecessors()) {
if (!cfgBlocksToProcess.contains(pred)) {
cfgBlocksToProcess.add(pred);
}
}
}
// Remove this block, since it has been processed
cfgBlocksToProcess.remove(block);
return bFlow;
}
private void calculateGenKillSets(CFGBlock block, BlockDataFlowState bFlow) {
for (int i = block.getStatements().size() - 1; i >= 0; i--) {
LIRStatement stmt = block.getStatements().get(i);
if (stmt.getClass().equals(QuadrupletStmt.class)) {
QuadrupletStmt qStmt = (QuadrupletStmt) stmt;
if (!qStmt.getDestination().getClass().equals(RegisterName.class)) {
updateKillGenSet(block.getMethodName(), qStmt, bFlow);
}
} else if (stmt.getClass().equals(StoreStmt.class)) {
updateKillGenSet(block.getMethodName(), (StoreStmt) stmt, bFlow);
} else if (stmt.getClass().equals(CallStmt.class)) {
updateKillGenSet(block.getMethodName(), (CallStmt) stmt, bFlow);
}
}
}
private void setExitBlock(String methodName) {
for (CFGBlock block : this.mMap.get(methodName).getCfgBlocks()) {
if (block.getSuccessors().size() == 0) {
// return block;
CFGBlock exit = block;
BlockDataFlowState entryBlockFlow =
new BlockDataFlowState(
this.uniqueGlobals.get(methodName).size()); // IN = GEN for entry block
calculateGenKillSets(exit, entryBlockFlow);
entryBlockFlow.setIn(entryBlockFlow.getGen());
cfgBlocksToProcess.remove(exit);
this.cfgBlocksState.put(exit, entryBlockFlow);
}
}
}
private void initialize(String methodName) {
this.cfgBlocksToProcess.clear();
HashSet<Name> temp = new HashSet<Name>();
for (CFGBlock block : this.mMap.get(methodName).getCfgBlocks()) {
List<LIRStatement> blockStmts = block.getStatements();
for (int i = 0; i < blockStmts.size(); i++) {
LIRStatement stmt = blockStmts.get(i);
if (stmt.getClass().equals(QuadrupletStmt.class)) {
QuadrupletStmt qStmt = (QuadrupletStmt) stmt;
if (qStmt.getDestination().isGlobal()) temp.add(qStmt.getDestination());
} else if (stmt.getClass().equals(StoreStmt.class)) {
StoreStmt sStmt = (StoreStmt) stmt;
temp.add(sStmt.getVariable());
}
}
this.cfgBlocksToProcess.add(block);
}
this.uniqueGlobals.put(methodName, new ArrayList<Name>());
this.uniqueGlobals.get(methodName).addAll(temp);
}
private void optimize(CFGBlock block) {
BlockDataFlowState bFlow = assignmentDefGenerator.getBlockAssignReachingDefs().get(block);
QuadrupletStmt qStmt;
PopStmt popStmt;
PushStmt pushStmt;
CmpStmt cStmt;
Name newArg1, newArg2, dest;
for (LIRStatement stmt : block.getStatements()) {
// Reset kill set
bFlow.getKill().clear();
if (stmt.getClass().equals(CallStmt.class)) {
CallStmt callStmt = (CallStmt) stmt;
if (callStmt.getMethodLabel().equals(ProgramFlattener.exceptionHandlerLabel)) continue;
// Update BlockDataFlowState kill set
assignmentDefGenerator.invalidateFunctionCall(bFlow);
// Update BlockDataFlowState in set by using updated kill set
bFlow.getIn().xor(bFlow.getKill());
} else if (stmt.getClass().equals(QuadrupletStmt.class)) {
qStmt = (QuadrupletStmt) stmt;
newArg1 = copyPropagateOnArg(qStmt.getArg1(), bFlow);
if (newArg1 != null) {
qStmt.setArg1(newArg1);
}
newArg2 = copyPropagateOnArg(qStmt.getArg2(), bFlow);
if (newArg2 != null) {
qStmt.setArg2(newArg2);
}
dest = qStmt.getDestination();
if (dest != null) {
// Check if dest is ArrayName and try to optimize index
if (dest.getClass().equals(ArrayName.class)) {
Name arrIndex = ((ArrayName) dest).getIndex();
Name propagatedName = copyPropagateOnArg(arrIndex, bFlow);
if (propagatedName != null) ((ArrayName) dest).setIndex(propagatedName);
}
}
// Update BlockDataFlowState kill set
assignmentDefGenerator.updateKillGenSet(dest, bFlow);
// Update BlockDataFlowState in set by using updated kill set
bFlow.getIn().xor(bFlow.getKill());
// Optimize PopStmt
} else if (stmt.getClass().equals(PopStmt.class)) {
popStmt = (PopStmt) stmt;
newArg1 = copyPropagateOnArg(popStmt.getName(), bFlow);
if (newArg1 != null) {
popStmt.setName(newArg1);
}
// Optimize PushStmt
} else if (stmt.getClass().equals(PushStmt.class)) {
pushStmt = (PushStmt) stmt;
newArg1 = copyPropagateOnArg(pushStmt.getName(), bFlow);
if (newArg1 != null) {
pushStmt.setName(newArg1);
}
// Optimize CmpStmt
} else if (stmt.getClass().equals(CmpStmt.class)) {
cStmt = (CmpStmt) stmt;
newArg1 = copyPropagateOnArg(cStmt.getArg1(), bFlow);
if (newArg1 != null) {
cStmt.setArg1(newArg1);
}
newArg2 = copyPropagateOnArg(cStmt.getArg2(), bFlow);
if (newArg2 != null) {
cStmt.setArg2(newArg2);
}
}
}
}