ojluni/src/main/java/sun/tools/tree/TryStatement.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.TryData;
 import sun.tools.asm.CatchData;
 import java.io.PrintStream;
 import java.util.Enumeration;
 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 TryStatement extends Statement {
     Statement body;
     Statement args[];
     long arrayCloneWhere;       // private note posted from MethodExpression

     /**
      * Constructor
      */
     public TryStatement(long where, Statement body, Statement args[]) {
         super(TRY, where);
         this.body = body;
         this.args = args;
     }

     /**
      * Check statement
      */
     Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
         checkLabel(env, ctx);
         try {
             vset = reach(env, vset);
             Hashtable newexp = new Hashtable();
             CheckContext newctx =  new CheckContext(ctx, this);

             // Check 'try' block.  A variable is DA (DU) before the try
             // block if it is DA (DU) before the try statement.
             Vset vs = body.check(env, newctx, vset.copy(), newexp);

             // A variable is DA before a catch block if it is DA before the
             // try statement.  A variable is DU before a catch block if it
             // is DU after the try block and before any 'break', 'continue',
             // 'throw', or 'return' contained therein. That is, the variable
             // is DU upon entry to the try-statement and is not assigned to
             // anywhere within the try block.
             Vset cvs = Vset.firstDAandSecondDU(vset, vs.copy().join(newctx.vsTryExit));

             for (int i = 0 ; i < args.length ; i++) {
                 // A variable is DA (DU) after a try statement if
                 // it is DA (DU) after every catch block.
                 vs = vs.join(args[i].check(env, newctx, cvs.copy(), exp));
             }

             // Check that catch statements are actually reached
             for (int i = 1 ; i < args.length ; i++) {
                 CatchStatement cs = (CatchStatement)args[i];
                 if (cs.field == null) {
                     continue;
                 }
                 Type type = cs.field.getType();
                 ClassDefinition def = env.getClassDefinition(type);

                 for (int j = 0 ; j < i ; j++) {
                     CatchStatement cs2 = (CatchStatement)args[j];
                     if (cs2.field == null) {
                         continue;
                     }
                     Type t = cs2.field.getType();
                     ClassDeclaration c = env.getClassDeclaration(t);
                     if (def.subClassOf(env, c)) {
                         env.error(args[i].where, "catch.not.reached");
                         break;
                     }
                 }
             }

             ClassDeclaration ignore1 = env.getClassDeclaration(idJavaLangError);
             ClassDeclaration ignore2 = env.getClassDeclaration(idJavaLangRuntimeException);

             // Make sure the exception is actually throw in that part of the code
             for (int i = 0 ; i < args.length ; i++) {
                 CatchStatement cs = (CatchStatement)args[i];
                 if (cs.field == null) {
                     continue;
                 }
                 Type type = cs.field.getType();
                 if (!type.isType(TC_CLASS)) {
                     // CatchStatement.checkValue() will have already printed
                     // an error message
                     continue;
                 }

                 ClassDefinition def = env.getClassDefinition(type);

                 // Anyone can throw these!
                 if (def.subClassOf(env, ignore1) || def.superClassOf(env, ignore1) ||
                     def.subClassOf(env, ignore2) || def.superClassOf(env, ignore2)) {
                     continue;
                 }

                 // Make sure the exception is actually throw in that part of the code
                 boolean ok = false;
                 for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
                     ClassDeclaration c = (ClassDeclaration)e.nextElement();
                     if (def.superClassOf(env, c) || def.subClassOf(env, c)) {
                         ok = true;
                         break;
                     }
                 }
                 if (!ok && arrayCloneWhere != 0
                     && def.getName().toString().equals("java.lang.CloneNotSupportedException")) {
                     env.error(arrayCloneWhere, "warn.array.clone.supported", def.getName());
                 }

                 if (!ok) {
                     env.error(cs.where, "catch.not.thrown", def.getName());
                 }
             }

             // Only carry over exceptions that are not caught
             for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
                 ClassDeclaration c = (ClassDeclaration)e.nextElement();
                 ClassDefinition def = c.getClassDefinition(env);
                 boolean add = true;
                 for (int i = 0 ; i < args.length ; i++) {
                     CatchStatement cs = (CatchStatement)args[i];
                     if (cs.field == null) {
                         continue;
                     }
                     Type type = cs.field.getType();
                     if (type.isType(TC_ERROR))
                         continue;
                     if (def.subClassOf(env, env.getClassDeclaration(type))) {
                         add = false;
                         break;
                     }
                 }
                 if (add) {
                     exp.put(c, newexp.get(c));
                 }
             }
             // A variable is DA (DU) after a try statement if it is DA (DU)
             // after the try block and after every catch block. These variables
             // are represented by 'vs'.  If the try statement is labelled, we
             // may also exit from it (including from within a catch block) via
             // a break statement.
             // If there is a finally block, the Vset returned here is further
             // adjusted. Note that this 'TryStatement' node will be a child of
             // a 'FinallyStatement' node in that case.
             return ctx.removeAdditionalVars(vs.join(newctx.vsBreak));
         } catch (ClassNotFound e) {
             env.error(where, "class.not.found", e.name, opNames[op]);
             return vset;
         }
     }

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

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

     /**
      * Compute cost of inlining this statement
      */
     public int costInline(int thresh, Environment env, Context ctx){

         // Don't inline methods containing try statements.
         // If the try statement is being inlined in order to
         // inline a method that returns a value which is
         // a subexpression of an expression involving the
         // operand stack, then the early operands may get lost.
         // This shows up as a verifier error.  For example,
         // in the following:
         //
         //    public static int test() {
         //       try { return 2; } catch (Exception e)  { return 0; }
         //    }
         //
         //    System.out.println(test());
         //
         // an inlined call to test() might look like this:
         //
         //     0 getstatic <Field java.io.PrintStream out>
         //     3 iconst_2
         //     4 goto 9
         //     7 pop
         //     8 iconst_0
         //     9 invokevirtual <Method void println(int)>
         //    12 return
         //  Exception table:
         //     from   to  target type
         //       3     7     7   <Class java.lang.Exception>
         //
         // This fails to verify because the operand stored
         // for System.out gets axed at an exception, leading to
         // an inconsistent stack depth at pc=7.
         //
         // Note that although all code must be able to be inlined
         // to implement initializers, this problem doesn't come up,
         // as try statements themselves can never be expressions.
         // It suffices here to make sure they are never inlined as part
         // of optimization.

         return thresh;
     }

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

         TryData td = new TryData();
         for (int i = 0 ; i < args.length ; i++) {
             Type t = ((CatchStatement)args[i]).field.getType();
             if (t.isType(TC_CLASS)) {
                 td.add(env.getClassDeclaration(t));
             } else {
                 td.add(t);
             }
         }
         asm.add(where, opc_try, td);
         if (body != null) {
             body.code(env, newctx, asm);
         }

         asm.add(td.getEndLabel());
         asm.add(where, opc_goto, newctx.breakLabel);

         for (int i = 0 ; i < args.length ; i++) {
             CatchData cd = td.getCatch(i);
             asm.add(cd.getLabel());
             args[i].code(env, newctx, asm);
             asm.add(where, opc_goto, newctx.breakLabel);
         }

         asm.add(newctx.breakLabel);
     }

     /**
      * Print
      */
     public void print(PrintStream out, int indent) {
         super.print(out, indent);
         out.print("try ");
         if (body != null) {
             body.print(out, indent);
         } else {
             out.print("<empty>");
         }
         for (int i = 0 ; i < args.length ; i++) {
             out.print(" ");
             args[i].print(out, indent);
         }
     }
 }
	/*
	* 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.TryData;
	import sun.tools.asm.CatchData;
	import java.io.PrintStream;
	import java.util.Enumeration;
	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 TryStatement extends Statement {
	Statement body;
	Statement args[];
	long arrayCloneWhere; // private note posted from MethodExpression

	/**
	* Constructor
	*/
	public TryStatement(long where, Statement body, Statement args[]) {
	super(TRY, where);
	this.body = body;
	this.args = args;
	}

	/**
	* Check statement
	*/
	Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
	checkLabel(env, ctx);
	try {
	vset = reach(env, vset);
	Hashtable newexp = new Hashtable();
	CheckContext newctx = new CheckContext(ctx, this);

	// Check 'try' block. A variable is DA (DU) before the try
	// block if it is DA (DU) before the try statement.
	Vset vs = body.check(env, newctx, vset.copy(), newexp);

	// A variable is DA before a catch block if it is DA before the
	// try statement. A variable is DU before a catch block if it
	// is DU after the try block and before any 'break', 'continue',
	// 'throw', or 'return' contained therein. That is, the variable
	// is DU upon entry to the try-statement and is not assigned to
	// anywhere within the try block.
	Vset cvs = Vset.firstDAandSecondDU(vset, vs.copy().join(newctx.vsTryExit));

	for (int i = 0 ; i < args.length ; i++) {
	// A variable is DA (DU) after a try statement if
	// it is DA (DU) after every catch block.
	vs = vs.join(args[i].check(env, newctx, cvs.copy(), exp));
	}

	// Check that catch statements are actually reached
	for (int i = 1 ; i < args.length ; i++) {
	CatchStatement cs = (CatchStatement)args[i];
	if (cs.field == null) {
	continue;
	}
	Type type = cs.field.getType();
	ClassDefinition def = env.getClassDefinition(type);

	for (int j = 0 ; j < i ; j++) {
	CatchStatement cs2 = (CatchStatement)args[j];
	if (cs2.field == null) {
	continue;
	}
	Type t = cs2.field.getType();
	ClassDeclaration c = env.getClassDeclaration(t);
	if (def.subClassOf(env, c)) {
	env.error(args[i].where, "catch.not.reached");
	break;
	}
	}
	}

	ClassDeclaration ignore1 = env.getClassDeclaration(idJavaLangError);
	ClassDeclaration ignore2 = env.getClassDeclaration(idJavaLangRuntimeException);

	// Make sure the exception is actually throw in that part of the code
	for (int i = 0 ; i < args.length ; i++) {
	CatchStatement cs = (CatchStatement)args[i];
	if (cs.field == null) {
	continue;
	}
	Type type = cs.field.getType();
	if (!type.isType(TC_CLASS)) {
	// CatchStatement.checkValue() will have already printed
	// an error message
	continue;
	}

	ClassDefinition def = env.getClassDefinition(type);

	// Anyone can throw these!
	if (def.subClassOf(env, ignore1) \|\| def.superClassOf(env, ignore1) \|\|
	def.subClassOf(env, ignore2) \|\| def.superClassOf(env, ignore2)) {
	continue;
	}

	// Make sure the exception is actually throw in that part of the code
	boolean ok = false;
	for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
	ClassDeclaration c = (ClassDeclaration)e.nextElement();
	if (def.superClassOf(env, c) \|\| def.subClassOf(env, c)) {
	ok = true;
	break;
	}
	}
	if (!ok && arrayCloneWhere != 0
	&& def.getName().toString().equals("java.lang.CloneNotSupportedException")) {
	env.error(arrayCloneWhere, "warn.array.clone.supported", def.getName());
	}

	if (!ok) {
	env.error(cs.where, "catch.not.thrown", def.getName());
	}
	}

	// Only carry over exceptions that are not caught
	for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
	ClassDeclaration c = (ClassDeclaration)e.nextElement();
	ClassDefinition def = c.getClassDefinition(env);
	boolean add = true;
	for (int i = 0 ; i < args.length ; i++) {
	CatchStatement cs = (CatchStatement)args[i];
	if (cs.field == null) {
	continue;
	}
	Type type = cs.field.getType();
	if (type.isType(TC_ERROR))
	continue;
	if (def.subClassOf(env, env.getClassDeclaration(type))) {
	add = false;
	break;
	}
	}
	if (add) {
	exp.put(c, newexp.get(c));
	}
	}
	// A variable is DA (DU) after a try statement if it is DA (DU)
	// after the try block and after every catch block. These variables
	// are represented by 'vs'. If the try statement is labelled, we
	// may also exit from it (including from within a catch block) via
	// a break statement.
	// If there is a finally block, the Vset returned here is further
	// adjusted. Note that this 'TryStatement' node will be a child of
	// a 'FinallyStatement' node in that case.
	return ctx.removeAdditionalVars(vs.join(newctx.vsBreak));
	} catch (ClassNotFound e) {
	env.error(where, "class.not.found", e.name, opNames[op]);
	return vset;
	}
	}

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

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

	/**
	* Compute cost of inlining this statement
	*/
	public int costInline(int thresh, Environment env, Context ctx){

	// Don't inline methods containing try statements.
	// If the try statement is being inlined in order to
	// inline a method that returns a value which is
	// a subexpression of an expression involving the
	// operand stack, then the early operands may get lost.
	// This shows up as a verifier error. For example,
	// in the following:
	//
	// public static int test() {
	// try { return 2; } catch (Exception e) { return 0; }
	// }
	//
	// System.out.println(test());
	//
	// an inlined call to test() might look like this:
	//
	// 0 getstatic <Field java.io.PrintStream out>
	// 3 iconst_2
	// 4 goto 9
	// 7 pop
	// 8 iconst_0
	// 9 invokevirtual <Method void println(int)>
	// 12 return
	// Exception table:
	// from to target type
	// 3 7 7 <Class java.lang.Exception>
	//
	// This fails to verify because the operand stored
	// for System.out gets axed at an exception, leading to
	// an inconsistent stack depth at pc=7.
	//
	// Note that although all code must be able to be inlined
	// to implement initializers, this problem doesn't come up,
	// as try statements themselves can never be expressions.
	// It suffices here to make sure they are never inlined as part
	// of optimization.

	return thresh;
	}

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

	TryData td = new TryData();
	for (int i = 0 ; i < args.length ; i++) {
	Type t = ((CatchStatement)args[i]).field.getType();
	if (t.isType(TC_CLASS)) {
	td.add(env.getClassDeclaration(t));
	} else {
	td.add(t);
	}
	}
	asm.add(where, opc_try, td);
	if (body != null) {
	body.code(env, newctx, asm);
	}

	asm.add(td.getEndLabel());
	asm.add(where, opc_goto, newctx.breakLabel);

	for (int i = 0 ; i < args.length ; i++) {
	CatchData cd = td.getCatch(i);
	asm.add(cd.getLabel());
	args[i].code(env, newctx, asm);
	asm.add(where, opc_goto, newctx.breakLabel);
	}

	asm.add(newctx.breakLabel);
	}

	/**
	* Print
	*/
	public void print(PrintStream out, int indent) {
	super.print(out, indent);
	out.print("try ");
	if (body != null) {
	body.print(out, indent);
	} else {
	out.print("<empty>");
	}
	for (int i = 0 ; i < args.length ; i++) {
	out.print(" ");
	args[i].print(out, indent);
	}
	}
	}