public void attachLivenessInfo(FlowGraph flowGraph, FlowGraphDecorator flowGraphDecorator) {
for (Function function : flowGraph.getFunctions()) {
// Perform liveness analysis
TransferFunction<LiveVariableState> transferFunction = new LiveVariableTransferFunction();
BackwardAnalysis<LiveVariableState> analysis =
new BackwardAnalysis<LiveVariableState>(flowGraphDecorator, function);
Map<Node, LiveVariableState> states = analysis.solve(transferFunction);
// Attach live variables to each basic block
for (BasicBlock basicBlock : function.getBlocks()) {
LiveVariableState state =
transferFunction.join(flowGraphDecorator, states, basicBlock.getLastNode());
Set<Integer> liveVariables = state.getLiveVariables();
// NOTE: The EdgeTransfer function may use the conditional variable contained in an if node.
// We check if the last node of the basic block is an if node, and if it is, we add
// the conditional variable to the set of live variables.
if (basicBlock.getLastNode() instanceof IfNode) {
IfNode ifNode = (IfNode) basicBlock.getLastNode();
liveVariables.add(ifNode.getConditionVar());
}
int[] result = new int[liveVariables.size()];
Iterator<Integer> iterator = liveVariables.iterator();
int i = 0;
while (iterator.hasNext()) {
result[i] = iterator.next();
i++;
}
basicBlock.setLiveVariables(result);
}
}
}
/** 11.13 and 11.1.2 assignment with left-hand-side identifier reference. */
@Override
public void visit(WriteVariableNode n, State state) {
Value v = state.readRegister(n.getValueRegister());
m.visitWriteVariable(n, v, state);
Set<ObjectLabel> objs = state.writeVariable(n.getVariableName(), v, true);
Function f = n.getBlock().getFunction();
if (f.getParameterNames().contains(n.getVariableName())) { // TODO: review
ObjectLabel arguments_obj = new ObjectLabel(f.getEntry().getFirstNode(), Kind.ARGUMENTS);
state.writeProperty(
arguments_obj, Integer.toString(f.getParameterNames().indexOf(n.getVariableName())), v);
}
m.visitPropertyWrite(n, objs, Value.makeTemporaryStr(n.getVariableName()));
m.visitVariableOrProperty(
n.getVariableName(), n.getSourceLocation(), v, state.getContext(), state);
}
/** Transfer ordinary and exceptional return for the given call node and callee entry. */
public void transferReturn(
AbstractNode call_node,
BasicBlock callee_entry,
Context caller_context,
Context callee_context,
Context edge_context) {
if (call_node instanceof BeginForInNode) {
for (EndForInNode endNode : ((BeginForInNode) call_node).getEndNodes()) {
BasicBlock end_block = endNode.getBlock();
if (c.getAnalysisLatticeElement().getState(end_block, callee_context)
!= null) // (EndForInNode uses same context as corresponding BeginForInNode)
c.addToWorklist(end_block, callee_context);
}
} else { // call_node is an ordinary call node
Function callee = callee_entry.getFunction();
BasicBlock ordinary_exit = callee.getOrdinaryExit();
BasicBlock exceptional_exit = callee.getExceptionalExit();
State ordinary_exit_state =
c.getAnalysisLatticeElement()
.getState(
ordinary_exit,
callee_context); // (ReturnNode uses same context as corresponding function entry
// node)
State exceptional_exit_state =
c.getAnalysisLatticeElement().getState(exceptional_exit, callee_context);
NodeAndContext<Context> caller = new NodeAndContext<>(call_node, caller_context);
if (ordinary_exit_state != null) {
if (ordinary_exit.getFirstNode() instanceof ReturnNode) {
ReturnNode returnNode = (ReturnNode) ordinary_exit.getFirstNode();
transferReturn(
returnNode.getReturnValueRegister(),
ordinary_exit,
ordinary_exit_state.clone(),
caller,
edge_context);
} else throw new AnalysisException("ReturnNode expected");
}
if (exceptional_exit_state != null) {
transferExceptionalReturn(
exceptional_exit, exceptional_exit_state.clone(), caller, edge_context);
}
}
}