Class IRFactory

rhino/src/main/java/org/mozilla/javascript/IRFactory.java:92–2637

This class rewrites the parse tree into an IR suitable for codegen. @see Node @author Mike McCabe @author Norris Boyd

 * @author Norris Boyd
 */
public final class IRFactory {
    private static final int LOOP_DO_WHILE = 0;
    private static final int LOOP_WHILE = 1;
    private static final int LOOP_FOR = 2;

    private static final int ALWAYS_TRUE_BOOLEAN = 1;
    private static final int ALWAYS_FALSE_BOOLEAN = -1;

    private Parser parser;
    private AstNodePosition astNodePos;
    private boolean outerScopeIsStrict;

    public IRFactory(CompilerEnvirons env, String sourceString) {
        this(env, null, sourceString, env.getErrorReporter());
    }

    /** Use {@link #IRFactory(CompilerEnvirons, String, String, ErrorReporter)} */
    @Deprecated
    public IRFactory(CompilerEnvirons env, String sourceString, ErrorReporter errorReporter) {
        this(env, null, sourceString, errorReporter);
    }

    public IRFactory(
            CompilerEnvirons env,
            String sourceName,
            String sourceString,
            ErrorReporter errorReporter) {
        parser = new Parser(env, errorReporter);
        astNodePos = new AstNodePosition(sourceString);
        parser.currentPos = astNodePos;
        parser.setSourceURI(sourceName);
    }

    /** Transforms the tree into a lower-level IR suitable for codegen. */
    public ScriptNode transformTree(AstRoot root) {
        parser.currentScriptOrFn = root;
        parser.inUseStrictDirective = root.isInStrictMode();

        if (Token.printTrees) {
            System.out.println("IRFactory.transformTree");
            System.out.println(root.debugPrint());
        }

        astNodePos.push(root);
        try {
            return (ScriptNode) transform(root);
        } catch (Parser.ParserException e) {
            parser.reportErrorsIfExists(root.getLineno());
            return null;
        } finally {
            astNodePos.pop();
        }
    }

    // Might want to convert this to polymorphism - move transform*
    // functions into the AstNode subclasses.  OTOH that would make
    // IR transformation part of the public AST API - desirable?
    // Another possibility:  create AstTransformer interface and adapter.