Automata, Languages and Compilers 2018/19 spring

Kompilaatori kodutöö, vihje 1

package week12;

import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.MethodVisitor;
import week11.AktkBinding;
import week9.AktkAst;
import week9.ast.*;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;

import static org.objectweb.asm.Opcodes.*;


public class AktkCompiler {

	public static void main(String[] args) throws IOException {
		// lihtsam viis "käsurea parameetrite andmiseks":
		//args = new String[] {"yks_pluss_yks.aktk"};

		if (args.length != 1) {
			throw new IllegalArgumentException("Sellele programmile tuleb anda parameetriks kompileeritava AKTK faili nimi");
		}

		Path sourceFile = Paths.get(args[0]);
		if (!Files.isRegularFile(sourceFile)) {
			throw new IllegalArgumentException("Ei leia faili nimega '" + sourceFile + "'");
		}

		String className = sourceFile.getFileName().toString().replace(".aktk", "");
		Path classFile = sourceFile.toAbsolutePath().getParent().resolve(className + ".class");

		createClassFile(sourceFile, className, classFile);
	}

	private static void createClassFile(Path sourceFile, String className, Path classFile) throws IOException {
		// loen faili sisu muutujasse
		String source = new String(Files.readAllBytes(sourceFile), StandardCharsets.UTF_8);

		// parsin ja moodustan AST'i
		AstNode ast = AktkAst.createAst(source);

		// seon muutujad
        AktkBinding.bind(ast);

		// kompileerin
		byte[] bytes = createClass(ast, className);
		Files.write(classFile, bytes);
	}

	public static byte[] createClass(AstNode ast, String className) {
		ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);

		// Klassi attribuudid
		cw.visit(V1_8, ACC_PUBLIC + ACC_SUPER, className, null, "java/lang/Object", null);
		cw.visitSource(null, null);

		// main meetod
		MethodVisitor mv = cw.visitMethod(
				ACC_PUBLIC + ACC_STATIC, 					// modifikaatorid
				"main",										// meetodi nimi
				"([Ljava/lang/String;)V",					// meetodi kirjeldaja
				null, 										// geneerikute info
				new String[] { "java/io/IOException" });
		mv.visitCode();
		// terve AKTK programm tuleb kompileerida main meetodi sisse
		new AktkCompilerVisitor(mv).visit(ast);
		mv.visitInsn(RETURN);
		mv.visitMaxs(0, 0);
		mv.visitEnd();


		// klassi lõpetamine
		cw.visitEnd();

		// klassi baidijada genereerimine
		return cw.toByteArray();
	}

	private static class AktkCompilerVisitor extends AstVisitor.VoidVisitor {

		private final Map<VariableBinding, Integer> variableIndices = new HashMap<>();;
		private final MethodVisitor mv;

		private AktkCompilerVisitor(MethodVisitor mv) {
			this.mv = mv;
		}

		private int getVariableIndex(VariableBinding binding) {
			Integer index = variableIndices.get(binding);
			if (index != null) {
				return index;
			}
			else {
				// muutuja 0 on meie main-meetodi parameeter

				index = variableIndices.size()+1;
				variableIndices.put(binding, index);
				return index;
			}
		}

		// ...
	}
}