public void applyTransferFunction(Instr i) {
// Rescue node, if any
boolean scopeBindingHasEscaped = problem.getScope().bindingHasEscaped();
Variable dst = null;
boolean dirtied = false;
boolean hitDFBarrier = false;
if (i instanceof ResultInstr) {
dst = ((ResultInstr) i).getResult();
}
if (i instanceof CopyInstr) {
// Copies are easy
Operand src = ((CopyInstr) i).getSource();
Class srcType = getOperandType(tmpState, src);
setOperandType(tmpState, dst, srcType);
// If we have an unboxed type for 'src', we can leave this unboxed.
//
// FIXME: However, if 'src' is a constant, this could unnecessarily
// leave 'src' unboxed and lead to a boxing instruction further down
// at the use site of 'dst'. This indicates that leaving this unboxed
// should ideally be done 'on-demand'. This indicates that this could
// be a backward-flow algo OR that this algo should be run on a
// dataflow graph / SSA graph.
if (srcType == Float.class) {
dirtied = true;
}
} else if (i instanceof CallBase) {
// Process calls specially -- these are what we want to optimize!
CallBase c = (CallBase) i;
Operand o = c.getClosureArg(null);
if (o == null) {
MethAddr m = c.getMethodAddr();
Operand r = c.getReceiver();
Operand[] args = c.getCallArgs();
if (args.length == 1 && m.resemblesALUOp()) {
Operand a = args[0];
Class receiverType = getOperandType(tmpState, r);
Class argType = getOperandType(tmpState, a);
// Optimistically assume that call is an ALU op
if (receiverType == Float.class
|| (receiverType == Fixnum.class && argType == Float.class)) {
setOperandType(tmpState, dst, Float.class);
// If 'r' and 'a' are not already in unboxed forms at this point,
// they will get unboxed after this, because we want to opt. this call
if (r instanceof Variable) {
tmpState.unboxedVars.add((Variable) r);
}
if (a instanceof Variable) {
tmpState.unboxedVars.add((Variable) a);
}
dirtied = true;
} else {
if (receiverType == Fixnum.class && argType == Fixnum.class) {
setOperandType(tmpState, dst, Fixnum.class);
} else {
setOperandType(tmpState, dst, Object.class);
}
if (c.targetRequiresCallersBinding()) {
hitDFBarrier = true;
}
}
} else {
setOperandType(tmpState, dst, Object.class);
}
} else {
if (o instanceof WrappedIRClosure) {
// Fetch the nested unboxing-analysis problem, creating one if necessary
IRClosure cl = ((WrappedIRClosure) o).getClosure();
UnboxableOpsAnalysisProblem subProblem =
(UnboxableOpsAnalysisProblem) cl.getDataFlowSolution(DataFlowConstants.UNBOXING);
if (subProblem == null) {
subProblem = new UnboxableOpsAnalysisProblem();
subProblem.setup(cl);
cl.setDataFlowSolution(DataFlowConstants.UNBOXING, subProblem);
}
UnboxableOpsAnalysisNode exitNode = (UnboxableOpsAnalysisNode) subProblem.getExitNode();
UnboxableOpsAnalysisNode entryNode = (UnboxableOpsAnalysisNode) subProblem.getEntryNode();
// Init it to MEET(state-on-entry, state-on-exit).
// The meet is required to account for participation of the closure in a loop.
// Ex: f = 0.0; n.times { f += 10; }
entryNode.inState = new UnboxState();
for (Variable v : tmpState.types.keySet()) {
if (v instanceof LocalVariable) {
entryNode.inState.types.put(v, tmpState.types.get(v));
}
}
entryNode.inState.computeMEET(exitNode.outState);
// Compute solution
subProblem.compute_MOP_Solution();
// Update types to MEET(new-state-on-exit, current-state)
tmpState.computeMEETForTypes(exitNode.outState, true);
// As for unboxed var state, since binding can escape in
// arbitrary ways in the general case, assume the worst for now.
// If we are guaranteed that the closure binding is not used
// outside the closure itself, we can avoid worst-case behavior
// and only clear vars that are modified in the closure.
hitDFBarrier = true;
} else {
// Black hole -- cannot analyze
hitDFBarrier = true;
}
}
} else {
// We dont know how to optimize this instruction.
// So, we assume we dont know type of the result.
// TOP/class --> BOTTOM
setOperandType(tmpState, dst, Object.class);
}
if (dirtied) {
tmpState.unboxedVars.add(dst);
tmpState.unboxedDirtyVars.add(dst);
} else {
// Since the instruction didn't run in unboxed form,
// dirty unboxed vars will have to get boxed here.
updateUnboxedVarsInfo(i, tmpState, dst, hasExceptionsRescued(), hitDFBarrier);
}
}
