public static boolean tryKillUnused(Node node) {
if (node.isAlive() && isFloatingNode().apply(node) && node.usages().isEmpty()) {
killWithUnusedFloatingInputs(node);
return true;
}
return false;
}
public static void killWithUnusedFloatingInputs(Node node) {
List<Node> floatingInputs = node.inputs().filter(isFloatingNode()).snapshot();
node.safeDelete();
for (Node in : floatingInputs) {
if (in.isAlive() && in.usages().isEmpty()) {
killWithUnusedFloatingInputs(in);
}
}
}
public static void killCFG(Node node, SimplifierTool tool) {
assert node.isAlive();
if (node instanceof AbstractEndNode) {
// We reached a control flow end.
AbstractEndNode end = (AbstractEndNode) node;
killEnd(end, tool);
} else {
// Normal control flow node.
/*
* We do not take a successor snapshot because this iterator supports concurrent
* modifications as long as they do not change the size of the successor list. Not
* taking a snapshot allows us to see modifications to other branches that may happen
* while processing one branch.
*/
for (Node successor : node.successors()) {
killCFG(successor, tool);
}
}
propagateKill(node);
}
/**
* Gets an approximate source code location for a node if possible.
*
* @return the StackTraceElements if an approximate source location is found, null otherwise
*/
public static StackTraceElement[] approxSourceStackTraceElement(Node node) {
ArrayList<StackTraceElement> elements = new ArrayList<>();
Node n = node;
while (n != null) {
if (n instanceof MethodCallTargetNode) {
elements.add(((MethodCallTargetNode) n).targetMethod().asStackTraceElement(-1));
n = ((MethodCallTargetNode) n).invoke().asNode();
}
if (n instanceof StateSplit) {
FrameState state = ((StateSplit) n).stateAfter();
while (state != null) {
ResolvedJavaMethod method = state.method();
if (method != null) {
elements.add(method.asStackTraceElement(state.bci - 1));
}
state = state.outerFrameState();
}
break;
}
n = n.predecessor();
}
return elements.toArray(new StackTraceElement[elements.size()]);
}
public static void propagateKill(Node node) {
if (node != null && node.isAlive()) {
List<Node> usagesSnapshot = node.usages().filter(isFloatingNode()).snapshot();
// null out remaining usages
node.replaceAtUsages(null);
node.replaceAtPredecessor(null);
killWithUnusedFloatingInputs(node);
for (Node usage : usagesSnapshot) {
if (!usage.isDeleted()) {
if (usage instanceof PhiNode) {
usage.replaceFirstInput(node, null);
} else {
propagateKill(usage);
}
}
}
}
}
public void deleteBranch(Node branch) {
branch.predecessor().replaceFirstSuccessor(branch, null);
GraphUtil.killCFG(branch, this);
}