package org.jruby.ir.passes;
import org.jruby.ir.IRScope;
import org.jruby.ir.instructions.CopyInstr;
import org.jruby.ir.instructions.Instr;
import org.jruby.ir.operands.Nil;
import org.jruby.ir.operands.TemporaryVariable;
import org.jruby.ir.operands.Variable;
import org.jruby.ir.representations.BasicBlock;
import org.jruby.ir.representations.CFG;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class EnsureTempsAssigned extends CompilerPass {
public static List<Class<? extends CompilerPass>> DEPENDENCIES = Arrays.<Class<? extends CompilerPass>>asList(CFGBuilder.class);
@Override
public String getLabel() {
return "Ensure Temporary Variables Assigned";
}
@Override
public List<Class<? extends CompilerPass>> getDependencies() {
return DEPENDENCIES;
}
@Override
public Object execute(IRScope scope, Object... data) {
processCFG(scope.getCFG());
return null;
}
private void processCFG(CFG cfg) {
Set<TemporaryVariable> names = new HashSet<TemporaryVariable>();
for (BasicBlock b : cfg.getBasicBlocks()) {
for (Instr i : b.getInstrs()) {
for (Variable v : i.getUsedVariables()) {
if (v instanceof TemporaryVariable) {
names.add((TemporaryVariable)v);
}
}
}
}
BasicBlock bb = cfg.getEntryBB();
int index = 0;
TemporaryVariable first = null;
for (TemporaryVariable name : names) {
if (first == null) {
bb.getInstrs().add(index++, new CopyInstr(name, new Nil()));
first = name;
} else {
bb.getInstrs().add(index++, new CopyInstr(name, first));
}
}
// recurse
for (IRScope childScope : cfg.getScope().getClosures()) {
run(childScope, false, true);
}
}
}