ojluni/src/main/java/sun/tools/tree/SwitchStatement.java - platform/libcore.git - Git at Google

 /*
  * 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
  * questions.
  */

 package sun.tools.tree;

 import sun.tools.java.*;
 import sun.tools.asm.Assembler;
 import sun.tools.asm.Label;
 import sun.tools.asm.SwitchData;
 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 SwitchStatement extends Statement {
     Expression expr;
     Statement args[];

     /**
      * Constructor
      */
     public SwitchStatement(long where, Expression expr, Statement args[]) {
         super(SWITCH, where);
         this.expr = expr;
         this.args = args;
     }

     /**
      * Check statement
      */
     Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
         checkLabel(env, ctx);
         CheckContext newctx = new CheckContext(ctx, this);
         vset = expr.checkValue(env, newctx, reach(env, vset), exp);
         Type switchType = expr.type;

         expr = convert(env, newctx, Type.tInt, expr);

         Hashtable tab = new Hashtable();
         boolean hasDefault = false;
         // Note that vs is reset to vset.copy() on every case label.
         // If the first substatement is not a case label, it is unreached.
         Vset vs = DEAD_END;

         for (int i = 0 ; i < args.length ; i++) {
             Statement s = args[i];

             if (s.op == CASE) {

                 vs = s.check(env, newctx, vs.join(vset.copy()), exp);

                 Expression lbl = ((CaseStatement)s).expr;
                 if (lbl != null) {
                     if (lbl instanceof IntegerExpression) {
                         Integer Ivalue =
                             (Integer)(((IntegerExpression)lbl).getValue());
                         int ivalue = Ivalue.intValue();
                         if (tab.get(lbl) != null) {
                             env.error(s.where, "duplicate.label", Ivalue);
                         } else {
                             tab.put(lbl, s);
                             boolean overflow;
                             switch (switchType.getTypeCode()) {
                                 case TC_BYTE:
                                     overflow = (ivalue != (byte)ivalue); break;
                                 case TC_SHORT:
                                     overflow = (ivalue != (short)ivalue); break;
                                 case TC_CHAR:
                                     overflow = (ivalue != (char)ivalue); break;
                                 default:
                                     overflow = false;
                             }
                             if (overflow) {
                                 env.error(s.where, "switch.overflow",
                                           Ivalue, switchType);
                             }
                         }
                     } else {
                         // Suppose a class got an error early on during
                         // checking.  It will set all of its members to
                         // have the status "ERROR".  Now suppose that a
                         // case label refers to one of this class's
                         // fields.  When we check the case label, the
                         // compiler will try to inline the FieldExpression.
                         // Since the expression has ERROR status, it doesn't
                         // inline.  This means that instead of the case
                         // label being an IntegerExpression, it will still
                         // be a FieldExpression, and we will end up in this
                         // else block.  So, before we just assume that
                         // the expression isn't constant, do a check to
                         // see if it was constant but unable to inline.
                         // This eliminates some spurious error messages.
                         // (Bug id 4067498).
                         if (!lbl.isConstant() ||
                             lbl.getType() != Type.tInt) {
                             env.error(s.where, "const.expr.required");
                         }
                     }
                 } else {
                     if (hasDefault) {
                         env.error(s.where, "duplicate.default");
                     }
                     hasDefault = true;
                 }
             } else {
                 vs = s.checkBlockStatement(env, newctx, vs, exp);
             }
         }
         if (!vs.isDeadEnd()) {
             newctx.vsBreak = newctx.vsBreak.join(vs);
         }
         if (hasDefault)
             vset = newctx.vsBreak;
         return ctx.removeAdditionalVars(vset);
     }

     /**
      * Inline
      */
     public Statement inline(Environment env, Context ctx) {
         ctx = new Context(ctx, this);
         expr = expr.inlineValue(env, ctx);
         for (int i = 0 ; i < args.length ; i++) {
             if (args[i] != null) {
                 args[i] = args[i].inline(env, ctx);
             }
         }
         return this;
     }

     /**
      * Create a copy of the statement for method inlining
      */
     public Statement copyInline(Context ctx, boolean valNeeded) {
         SwitchStatement s = (SwitchStatement)clone();
         s.expr = expr.copyInline(ctx);
         s.args = new Statement[args.length];
         for (int i = 0 ; i < args.length ; i++) {
             if (args[i] != null) {
                 s.args[i] = args[i].copyInline(ctx, valNeeded);
             }
         }
         return s;
     }

     /**
      * The cost of inlining this statement
      */
     public int costInline(int thresh, Environment env, Context ctx) {
         int cost = expr.costInline(thresh, env, ctx);
         for (int i = 0 ; (i < args.length) && (cost < thresh) ; i++) {
             if (args[i] != null) {
                 cost += args[i].costInline(thresh, env, ctx);
             }
         }
         return cost;
     }

     /**
      * Code
      */
     public void code(Environment env, Context ctx, Assembler asm) {
         CodeContext newctx = new CodeContext(ctx, this);

         expr.codeValue(env, newctx, asm);

         SwitchData sw = new SwitchData();
         boolean hasDefault = false;

         for (int i = 0 ; i < args.length ; i++) {
             Statement s = args[i];
             if ((s != null) && (s.op == CASE)) {
                 Expression e = ((CaseStatement)s).expr;
                 if (e != null) {
                     sw.add(((IntegerExpression)e).value, new Label());
                 }
 // JCOV
                 else {
                     hasDefault = true;
                 }
 // end JCOV
             }
         }

 // JCOV
         if (env.coverage())
             sw.initTableCase();
 // end JCOV
         asm.add(where, opc_tableswitch, sw);

         for (int i = 0 ; i < args.length ; i++) {
             Statement s = args[i];
             if (s != null) {
                 if (s.op == CASE) {
                     Expression e = ((CaseStatement)s).expr;
                     if (e != null) {
                         asm.add(sw.get(((IntegerExpression)e).value));
 // JCOV
                         sw.addTableCase(((IntegerExpression)e).value, s.where);
 // end JCOV
                     } else {
                         asm.add(sw.getDefaultLabel());
 // JCOV
                         sw.addTableDefault(s.where);
 // end JCOV
 /* JCOV                 hasDefault = true;   end JCOV */
                     }
                 } else {
                     s.code(env, newctx, asm);
                 }
             }
         }

         if (!hasDefault) {
             asm.add(sw.getDefaultLabel());
         }
         asm.add(newctx.breakLabel);
     }

     /**
      * Print
      */
     public void print(PrintStream out, int indent) {
         super.print(out, indent);
         out.print("switch (");
         expr.print(out);
         out.print(") {\n");
         for (int i = 0 ; i < args.length ; i++) {
             if (args[i] != null) {
                 printIndent(out, indent + 1);
                 args[i].print(out, indent + 1);
                 out.print("\n");
             }
         }
         printIndent(out, indent);
         out.print("}");
     }
 }
	/*
	* 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
	* questions.
	*/

	package sun.tools.tree;

	import sun.tools.java.*;
	import sun.tools.asm.Assembler;
	import sun.tools.asm.Label;
	import sun.tools.asm.SwitchData;
	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 SwitchStatement extends Statement {
	Expression expr;
	Statement args[];

	/**
	* Constructor
	*/
	public SwitchStatement(long where, Expression expr, Statement args[]) {
	super(SWITCH, where);
	this.expr = expr;
	this.args = args;
	}

	/**
	* Check statement
	*/
	Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
	checkLabel(env, ctx);
	CheckContext newctx = new CheckContext(ctx, this);
	vset = expr.checkValue(env, newctx, reach(env, vset), exp);
	Type switchType = expr.type;

	expr = convert(env, newctx, Type.tInt, expr);

	Hashtable tab = new Hashtable();
	boolean hasDefault = false;
	// Note that vs is reset to vset.copy() on every case label.
	// If the first substatement is not a case label, it is unreached.
	Vset vs = DEAD_END;

	for (int i = 0 ; i < args.length ; i++) {
	Statement s = args[i];

	if (s.op == CASE) {

	vs = s.check(env, newctx, vs.join(vset.copy()), exp);

	Expression lbl = ((CaseStatement)s).expr;
	if (lbl != null) {
	if (lbl instanceof IntegerExpression) {
	Integer Ivalue =
	(Integer)(((IntegerExpression)lbl).getValue());
	int ivalue = Ivalue.intValue();
	if (tab.get(lbl) != null) {
	env.error(s.where, "duplicate.label", Ivalue);
	} else {
	tab.put(lbl, s);
	boolean overflow;
	switch (switchType.getTypeCode()) {
	case TC_BYTE:
	overflow = (ivalue != (byte)ivalue); break;
	case TC_SHORT:
	overflow = (ivalue != (short)ivalue); break;
	case TC_CHAR:
	overflow = (ivalue != (char)ivalue); break;
	default:
	overflow = false;
	}
	if (overflow) {
	env.error(s.where, "switch.overflow",
	Ivalue, switchType);
	}
	}
	} else {
	// Suppose a class got an error early on during
	// checking. It will set all of its members to
	// have the status "ERROR". Now suppose that a
	// case label refers to one of this class's
	// fields. When we check the case label, the
	// compiler will try to inline the FieldExpression.
	// Since the expression has ERROR status, it doesn't
	// inline. This means that instead of the case
	// label being an IntegerExpression, it will still
	// be a FieldExpression, and we will end up in this
	// else block. So, before we just assume that
	// the expression isn't constant, do a check to
	// see if it was constant but unable to inline.
	// This eliminates some spurious error messages.
	// (Bug id 4067498).
	if (!lbl.isConstant() \|\|
	lbl.getType() != Type.tInt) {
	env.error(s.where, "const.expr.required");
	}
	}
	} else {
	if (hasDefault) {
	env.error(s.where, "duplicate.default");
	}
	hasDefault = true;
	}
	} else {
	vs = s.checkBlockStatement(env, newctx, vs, exp);
	}
	}
	if (!vs.isDeadEnd()) {
	newctx.vsBreak = newctx.vsBreak.join(vs);
	}
	if (hasDefault)
	vset = newctx.vsBreak;
	return ctx.removeAdditionalVars(vset);
	}

	/**
	* Inline
	*/
	public Statement inline(Environment env, Context ctx) {
	ctx = new Context(ctx, this);
	expr = expr.inlineValue(env, ctx);
	for (int i = 0 ; i < args.length ; i++) {
	if (args[i] != null) {
	args[i] = args[i].inline(env, ctx);
	}
	}
	return this;
	}

	/**
	* Create a copy of the statement for method inlining
	*/
	public Statement copyInline(Context ctx, boolean valNeeded) {
	SwitchStatement s = (SwitchStatement)clone();
	s.expr = expr.copyInline(ctx);
	s.args = new Statement[args.length];
	for (int i = 0 ; i < args.length ; i++) {
	if (args[i] != null) {
	s.args[i] = args[i].copyInline(ctx, valNeeded);
	}
	}
	return s;
	}

	/**
	* The cost of inlining this statement
	*/
	public int costInline(int thresh, Environment env, Context ctx) {
	int cost = expr.costInline(thresh, env, ctx);
	for (int i = 0 ; (i < args.length) && (cost < thresh) ; i++) {
	if (args[i] != null) {
	cost += args[i].costInline(thresh, env, ctx);
	}
	}
	return cost;
	}

	/**
	* Code
	*/
	public void code(Environment env, Context ctx, Assembler asm) {
	CodeContext newctx = new CodeContext(ctx, this);

	expr.codeValue(env, newctx, asm);

	SwitchData sw = new SwitchData();
	boolean hasDefault = false;

	for (int i = 0 ; i < args.length ; i++) {
	Statement s = args[i];
	if ((s != null) && (s.op == CASE)) {
	Expression e = ((CaseStatement)s).expr;
	if (e != null) {
	sw.add(((IntegerExpression)e).value, new Label());
	}
	// JCOV
	else {
	hasDefault = true;
	}
	// end JCOV
	}
	}

	// JCOV
	if (env.coverage())
	sw.initTableCase();
	// end JCOV
	asm.add(where, opc_tableswitch, sw);

	for (int i = 0 ; i < args.length ; i++) {
	Statement s = args[i];
	if (s != null) {
	if (s.op == CASE) {
	Expression e = ((CaseStatement)s).expr;
	if (e != null) {
	asm.add(sw.get(((IntegerExpression)e).value));
	// JCOV
	sw.addTableCase(((IntegerExpression)e).value, s.where);
	// end JCOV
	} else {
	asm.add(sw.getDefaultLabel());
	// JCOV
	sw.addTableDefault(s.where);
	// end JCOV
	/* JCOV hasDefault = true; end JCOV */
	}
	} else {
	s.code(env, newctx, asm);
	}
	}
	}

	if (!hasDefault) {
	asm.add(sw.getDefaultLabel());
	}
	asm.add(newctx.breakLabel);
	}

	/**
	* Print
	*/
	public void print(PrintStream out, int indent) {
	super.print(out, indent);
	out.print("switch (");
	expr.print(out);
	out.print(") {\n");
	for (int i = 0 ; i < args.length ; i++) {
	if (args[i] != null) {
	printIndent(out, indent + 1);
	args[i].print(out, indent + 1);
	out.print("\n");
	}
	}
	printIndent(out, indent);
	out.print("}");
	}
	}