ForStatement.java

/*
 * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
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package sun.tools.tree;

import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import java.io.PrintStream;
import java.util.Hashtable;

/**
 * WARNING: The contents of this source file are not part of any
 * supported API.  Code that depends on them does so at its own risk:
 * they are subject to change or removal without notice.
 */
public
class ForStatement extends Statement {
    Statement init;
    Expression cond;
    Expression inc;
    Statement body;

    /**
     * Constructor
     */
    public ForStatement(long where, Statement init, Expression cond, Expression inc, Statement body) {
	super(FOR, where);
	this.init = init;
	this.cond = cond;
	this.inc = inc;
	this.body = body;
    }

    /**
     * Check statement
     */
    Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
	checkLabel(env, ctx);
	vset = reach(env, vset);
	Context initctx = new Context(ctx, this);
	if (init != null) {
	    vset = init.checkBlockStatement(env, initctx, vset, exp);
	}
	CheckContext newctx = new CheckContext(initctx, this);
	// remember what was unassigned on entry
	Vset vsEntry = vset.copy();
	ConditionVars cvars;
	if (cond != null) {
	    cvars = cond.checkCondition(env, newctx, vset, exp);
	    cond = convert(env, newctx, Type.tBoolean, cond);
	} else {
	    // a missing test is equivalent to "true"
	    cvars = new ConditionVars();
	    cvars.vsFalse = Vset.DEAD_END; 
	    cvars.vsTrue = vset;
	}
	vset = body.check(env, newctx, cvars.vsTrue, exp);
	vset = vset.join(newctx.vsContinue);
	if (inc != null) {
	    vset = inc.check(env, newctx, vset, exp);
	}
	// Make sure the back-branch fits the entry of the loop.
	// Must include variables declared in the for-init part in the
	// set of variables visible upon loop entry that must be checked.
	initctx.checkBackBranch(env, this, vsEntry, vset);
	// exit by testing false or executing a break;
	vset = newctx.vsBreak.join(cvars.vsFalse);
	return ctx.removeAdditionalVars(vset);
    }

    /**
     * Inline
     */
    public Statement inline(Environment env, Context ctx) {
	ctx = new Context(ctx, this);
	if (init != null) {
	    Statement body[] = {init, this};
	    init = null;
	    return new CompoundStatement(where, body).inline(env, ctx);
	}
	if (cond != null) {
	    cond = cond.inlineValue(env, ctx);
	}
	if (body != null) {
	    body = body.inline(env, ctx);
	}
	if (inc != null) {
	    inc = inc.inline(env, ctx);
	}
	return this;
    }

    /**
     * Create a copy of the statement for method inlining
     */
    public Statement copyInline(Context ctx, boolean valNeeded) {
	ForStatement s = (ForStatement)clone();
	if (init != null) {
	    s.init = init.copyInline(ctx, valNeeded);
	}
	if (cond != null) {
	    s.cond = cond.copyInline(ctx);
	}
	if (body != null) {
	    s.body = body.copyInline(ctx, valNeeded);
	}
	if (inc != null) {
	    s.inc = inc.copyInline(ctx);
	}
	return s;
    }

    /**
     * The cost of inlining this statement
     */
    public int costInline(int thresh, Environment env, Context ctx) {
	int cost = 2;
	if (init != null) {
	    cost += init.costInline(thresh, env, ctx);
	}
	if (cond != null) {
	    cost += cond.costInline(thresh, env, ctx);
	}
	if (body != null) {
	    cost += body.costInline(thresh, env, ctx);
	}
	if (inc != null) {
	    cost += inc.costInline(thresh, env, ctx);
	}
	return cost;
    }

    /**
     * Code
     */
    public void code(Environment env, Context ctx, Assembler asm) {
	CodeContext newctx = new CodeContext(ctx, this);
	if (init != null) {
	    init.code(env, newctx, asm);
	}

	Label l1 = new Label();
	Label l2 = new Label();

	asm.add(where, opc_goto, l2);

	asm.add(l1);
	if (body != null) {
	    body.code(env, newctx, asm);
	}

	asm.add(newctx.contLabel);
	if (inc != null) {
	    inc.code(env, newctx, asm);
	}

	asm.add(l2);
	if (cond != null) {
	    cond.codeBranch(env, newctx, asm, l1, true);
	} else {
	    asm.add(where, opc_goto, l1);
	}
	asm.add(newctx.breakLabel);
    }

    /**
     * Print
     */
    public void print(PrintStream out, int indent) {
	super.print(out, indent);
	out.print("for (");
	if (init != null) {
	    init.print(out, indent);
	    out.print(" ");
	} else {
	    out.print("; ");
	}
	if (cond != null) {
	    cond.print(out);
	    out.print(" ");
	}
	out.print("; ");
	if (inc != null) {
	    inc.print(out);
	}
	out.print(") ");
	if (body != null) {
	    body.print(out, indent);
	} else {
	    out.print(";");
	}
    }
}