com.tangosol.dev.compiler.java.ContinueStatement Maven / Gradle / Ivy

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/*
 * Copyright (c) 2000, 2020, Oracle and/or its affiliates.
 *
 * Licensed under the Universal Permissive License v 1.0 as shown at
 * http://oss.oracle.com/licenses/upl.
 */


package com.tangosol.dev.compiler.java;


import com.tangosol.dev.assembler.CodeAttribute;
import com.tangosol.dev.assembler.Goto;
import com.tangosol.dev.assembler.Label;

import com.tangosol.dev.compiler.CompilerException;
import com.tangosol.dev.compiler.Context;

import com.tangosol.dev.component.DataType;

import com.tangosol.util.ErrorList;

import java.util.Set;
import java.util.Map;


/**
* This class implements the continue statement.
*
*   ContinueStatement:
*       continue Identifier-opt ;
*
* @version 1.00, 09/21/98
* @author  Cameron Purdy
*/
public class ContinueStatement extends BranchStatement
    {
    // ----- construction ---------------------------------------------------

    /**
    * Construct a continue statement.
    *
    * @param stmt      the statement within which this element exists
    * @param tokFirst  the first token of the statement
    * @param tokLabel  the optional branch label
    */
    public ContinueStatement(Statement stmt, Token tokFirst, Token tokLabel)
        {
        super(stmt, tokFirst, tokLabel);
        }


    // ----- code generation ------------------------------------------------

    /**
    * Perform semantic checks, parse tree re-organization, name binding,
    * and optimizations.
    *
    * @param ctx        the compiler context
    * @param setUVars   the set of potentially unassigned variables
    * @param setFVars   the set of potentially assigned final variables
    * @param mapThrown  the set of potentially thrown checked exceptions
    * @param errlist    the error list
    *
    * @exception CompilerException  thrown if an error occurs that should
    *            stop the compilation process
    */
    protected Element precompile(Context ctx, DualSet setUVars, DualSet setFVars, Map mapThrown, ErrorList errlist)
            throws CompilerException
        {
        String    sName = getLabelName();
        Statement stmt  = getOuterStatement();

        if (sName == null)
            {
            // find the first enclosing while, do, or for statement
            while (stmt != null)
                {
                if (stmt instanceof WhileStatement  ||
                    stmt instanceof DoStatement     ||
                    stmt instanceof ForStatement)
                    {
                    break;
                    }

                stmt = stmt.getOuterStatement();
                }

            if (stmt == null)
                {
                logError(ERROR, CONTINUE_TARGET, null, errlist);
                }
            }
        else
            {
            // find the enclosing label statement to break to
            while (stmt != null)
                {
                if (stmt instanceof LabelStatement &&
                    sName.equals(((LabelStatement) stmt).getName()))
                    {
                    break;
                    }

                stmt = stmt.getOuterStatement();
                }

            if (stmt == null)
                {
                getLabelToken().logError(ERROR, LABEL_MISSING, new String[] {sName}, errlist);
                }
            else
                {
                stmt = stmt.getInnerStatement();
                if (!(stmt instanceof WhileStatement  ||
                      stmt instanceof DoStatement     ||
                      stmt instanceof ForStatement))
                    {
                    logError(ERROR, CONTINUE_TARGET, null, errlist);
                    stmt = null;
                    }
                }
            }

        if (stmt != null)
            {
            // we will need the loop continuation label, so ask for it now
            stmt.getContinuationLabel();

            // register all unassigned variables with the target statement
            if (!setUVars.isEmpty())
                {
                stmt.addContinueUVars(setUVars);
                }

            // register all assigned final variables with the target statement
            if (!setFVars.isEmpty())
                {
                stmt.addContinueFVars(setFVars);
                }

            setTargetStatement(stmt);
            }

        // JLS 16.2.11:  By convention, we say that V is definitely assigned
        // after any break, continue, return, or throw statement.
        setUVars.clear();
        setFVars.clear();

        return this;
        }

    /**
    * Perform final optimizations and code generation.
    *
    * @param ctx       the compiler context
    * @param code      the assembler code attribute to compile to
    * @param fReached  true if this language element is reached (JLS 14.19)
    * @param errlist   the error list to log errors to
    *
    * @return true if the element can complete normally (JLS 14.1)
    *
    * @exception CompilerException  thrown if an error occurs that should
    *            stop the compilation process
    */
    protected boolean compileImpl(Context ctx, CodeAttribute code, boolean fReached, ErrorList errlist)
            throws CompilerException
        {
        // compilation for continue:
        //
        //          jsr     lblFinally[0]       ; innermost finally
        //          jsr     lblFinally[1]       ; next innermost
        //          ...                         ; and so on
        //          goto    lblContinuation     ; continuation point

        // invoke the finally clauses
        compileFinallyClauses(code);

        // jump to continuation point
        code.add(new Goto(getTargetStatement().getContinuationLabel()));

        // JLS 14.19: A break, continue, return, or throw statement cannot
        // complete normally.
        return false;
        }


    // ----- data members ---------------------------------------------------

    /**
    * The class name.
    */
    private static final String CLASS = "ContinueStatement";
    }