package org.renjin.compiler.ir.tac.functions;
import org.renjin.compiler.ir.tac.IRBodyBuilder;
import org.renjin.compiler.ir.tac.IRLabel;
import org.renjin.compiler.ir.tac.expressions.CmpGE;
import org.renjin.compiler.ir.tac.expressions.Constant;
import org.renjin.compiler.ir.tac.expressions.ElementAccess;
import org.renjin.compiler.ir.tac.expressions.EnvironmentVariable;
import org.renjin.compiler.ir.tac.expressions.Expression;
import org.renjin.compiler.ir.tac.expressions.Increment;
import org.renjin.compiler.ir.tac.expressions.Length;
import org.renjin.compiler.ir.tac.expressions.LocalVariable;
import org.renjin.compiler.ir.tac.expressions.PrimitiveCall;
import org.renjin.compiler.ir.tac.expressions.Temp;
import org.renjin.compiler.ir.tac.expressions.Variable;
import org.renjin.compiler.ir.tac.statements.Assignment;
import org.renjin.compiler.ir.tac.statements.GotoStatement;
import org.renjin.compiler.ir.tac.statements.IfStatement;
import org.renjin.sexp.FunctionCall;
import org.renjin.sexp.Null;
import org.renjin.sexp.SEXP;
import org.renjin.sexp.Symbol;
import com.google.common.collect.Lists;
public class ForTranslator extends FunctionCallTranslator {
@Override
public Symbol getName() {
return Symbol.get("for");
}
@Override
public Expression translateToExpression(IRBodyBuilder builder, TranslationContext context, FunctionCall call) {
addForLoop(builder, context, call);
return new Constant(Null.INSTANCE);
}
@Override
public void addStatement(IRBodyBuilder builder, TranslationContext context, FunctionCall call) {
addForLoop(builder, context, call);
}
private void addForLoop(IRBodyBuilder factory, TranslationContext context, FunctionCall call) {
Symbol symbol = call.getArgument(0);
LocalVariable counter = factory.newLocalVariable();
Temp length = factory.newTemp();
Variable elementVariable = new EnvironmentVariable(symbol);
Expression vector =
factory.translateSimpleExpression(context, call.getArgument(1));
SEXP body = call.getArgument(2);
IRLabel counterLabel = factory.newLabel();
IRLabel bodyLabel = factory.newLabel();
IRLabel nextLabel = factory.newLabel();
IRLabel exitLabel = factory.newLabel();
// initialize the counter
factory.addStatement(new Assignment(counter, new Constant(0)));
factory.addStatement(new Assignment(length,
new Length((Expression)vector)));
// check the counter and potentially loop
factory.addLabel(counterLabel);
factory.addStatement(new IfStatement(new CmpGE(counter, length), exitLabel, bodyLabel));
// start the body here
factory.addLabel(bodyLabel);
factory.addStatement(new Assignment(elementVariable, new ElementAccess(vector, counter)));
LoopContext loopContext = new LoopContext(nextLabel, exitLabel);
factory.translateStatements(loopContext, body);
// increment the counter
factory.addLabel(nextLabel);
factory.addStatement(new Assignment(counter, new Increment(counter)));
factory.addStatement(new GotoStatement(counterLabel));
factory.addLabel(exitLabel);
}
}