//
// This can help use eliminate writes to %block that are not used since this is
// a special local-variable, not programmer-defined local-variable
public void computeScopeFlags() {
if (flagsComputed) {
return;
}
// init
canModifyCode = true;
canCaptureCallersBinding = false;
usesZSuper = false;
usesEval = false;
usesBackrefOrLastline = false;
// NOTE: bindingHasEscaped is the crucial flag and it effectively is
// unconditionally true whenever it has a call that receives a closure.
// See CallInstr.computeRequiresCallersBindingFlag
bindingHasEscaped =
(this instanceof IREvalScript); // for eval scopes, bindings are considered escaped ...
hasBreakInstrs = false;
hasNonlocalReturns = false;
canReceiveBreaks = false;
canReceiveNonlocalReturns = false;
// recompute flags -- we could be calling this method different times
// definitely once after ir generation and local optimizations propagates constants locally
// but potentially at a later time after doing ssa generation and constant propagation
if (cfg == null) {
computeScopeFlags(false, getInstrs());
} else {
boolean receivesClosureArg = false;
for (BasicBlock b : cfg.getBasicBlocks()) {
receivesClosureArg = computeScopeFlags(receivesClosureArg, b.getInstrs());
}
}
// Compute flags for nested closures (recursively) and set derived flags.
for (IRClosure cl : getClosures()) {
cl.computeScopeFlags();
if (cl.hasBreakInstrs || cl.canReceiveBreaks) {
canReceiveBreaks = true;
}
if (cl.hasNonlocalReturns || cl.canReceiveNonlocalReturns) {
canReceiveNonlocalReturns = true;
}
if (cl.usesZSuper()) {
usesZSuper = true;
}
}
flagsComputed = true;
}
