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1   /*
2    * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  package sun.tools.tree;
27  
28  import sun.tools.java.*;
29  import sun.tools.asm.Assembler;
30  import sun.tools.asm.LocalVariable;
31  import java.io.PrintStream;
32  import java.util.Hashtable;
33  
34  /**
35   * WARNING: The contents of this source file are not part of any
36   * supported API.  Code that depends on them does so at its own risk:
37   * they are subject to change or removal without notice.
38   */
39  public
40  class VarDeclarationStatement extends Statement {
41      LocalMember field;
42      Expression expr;
43  
44      /**
45       * Constructor
46       */
47      public VarDeclarationStatement(long where, Expression expr) {
48          super(VARDECLARATION, where);
49          this.expr = expr;
50      }
51      public VarDeclarationStatement(long where, LocalMember field, Expression expr) {
52          super(VARDECLARATION, where);
53          this.field = field;
54          this.expr = expr;
55      }
56  
57      /**
58       * Check statement
59       */
60      Vset checkDeclaration(Environment env, Context ctx, Vset vset, int mod, Type t, Hashtable exp) {
61          if (labels != null) {
62              env.error(where, "declaration.with.label", labels[0]);
63          }
64          if (field != null) {
65              if (ctx.getLocalClass(field.getName()) != null
66                  && field.isInnerClass()) {
67                  env.error(where, "local.class.redefined", field.getName());
68              }
69  
70              ctx.declare(env, field);
71              if (field.isInnerClass()) {
72                  ClassDefinition body = field.getInnerClass();
73                  try {
74                      vset = body.checkLocalClass(env, ctx, vset,
75                                                  null, null, null);
76                  } catch (ClassNotFound ee) {
77                      env.error(where, "class.not.found", ee.name, opNames[op]);
78                  }
79                  return vset;
80              }
81              vset.addVar(field.number);
82              return (expr != null) ? expr.checkValue(env, ctx, vset, exp) : vset;
83          }
84  
85          // Argument 'expr' is either an IdentifierExpression for a declaration of
86          // the form 'type x' or an AssignmentExpression for a declaration of the
87          // form 'type x = initvalue'.  Note that these expressions are treated
88          // specially in this context, and don't have much connection to their ordinary
89          // meaning.
90  
91          Expression e = expr;
92  
93          if (e.op == ASSIGN) {
94              expr = ((AssignExpression)e).right;
95              e = ((AssignExpression)e).left;
96          } else {
97              expr = null;
98          }
99  
100         boolean declError = t.isType(TC_ERROR);
101         while (e.op == ARRAYACCESS) {
102             ArrayAccessExpression array = (ArrayAccessExpression)e;
103             if (array.index != null) {
104                 env.error(array.index.where, "array.dim.in.type");
105                 declError = true;
106             }
107             e = array.right;
108             t = Type.tArray(t);
109         }
110         if (e.op == IDENT) {
111             Identifier id = ((IdentifierExpression)e).id;
112             if (ctx.getLocalField(id) != null) {
113                 env.error(where, "local.redefined", id);
114             }
115 
116             field = new LocalMember(e.where, ctx.field.getClassDefinition(), mod, t, id);
117             ctx.declare(env, field);
118 
119             if (expr != null) {
120                 vset = expr.checkInitializer(env, ctx, vset, t, exp);
121                 expr = convert(env, ctx, t, expr);
122                 field.setValue(expr); // for the sake of non-blank finals
123                 if (field.isConstant()) {
124                     // Keep in mind that isConstant() only means expressions
125                     // that are constant according to the JLS.  They might
126                     // not be either constants or evaluable (eg. 1/0).
127                     field.addModifiers(M_INLINEABLE);
128                 }
129                 vset.addVar(field.number);
130             } else if (declError) {
131                 vset.addVar(field.number);
132             } else {
133                 vset.addVarUnassigned(field.number);
134             }
135             return vset;
136         }
137         env.error(e.where, "invalid.decl");
138         return vset;
139     }
140 
141     /**
142      * Inline
143      */
144     public Statement inline(Environment env, Context ctx) {
145         if (field.isInnerClass()) {
146             ClassDefinition body = field.getInnerClass();
147             body.inlineLocalClass(env);
148             return null;
149         }
150 
151         // Don't generate code for variable if unused and
152         // optimization is on, whether or not debugging is on
153         if (env.opt() && !field.isUsed()) {
154             return new ExpressionStatement(where, expr).inline(env, ctx);
155         }
156 
157         ctx.declare(env, field);
158 
159         if (expr != null) {
160             expr = expr.inlineValue(env, ctx);
161             field.setValue(expr); // for the sake of non-blank finals
162             if (env.opt() && (field.writecount == 0)) {
163                 if (expr.op == IDENT) {
164 
165                     // This code looks like it tests whether a final variable
166                     // is being initialized by an identifier expression.
167                     // Then if the identifier is a local of the same method
168                     // it makes the final variable eligible to be inlined.
169                     // BUT: why isn't the local also checked to make sure
170                     // it is itself final?  Unknown.
171 
172                     IdentifierExpression e = (IdentifierExpression)expr;
173                     if (e.field.isLocal() && ((ctx = ctx.getInlineContext()) != null) &&
174                         (((LocalMember)e.field).number < ctx.varNumber)) {
175                         //System.out.println("FINAL IDENT = " + field + " in " + ctx.field);
176                         field.setValue(expr);
177                         field.addModifiers(M_INLINEABLE);
178 
179                         // The two lines below used to elide the declaration
180                         // of inlineable variables, on the theory that there
181                         // wouldn't be any references.  But this breaks the
182                         // translation of nested classes, which might refer to
183                         // the variable.
184 
185                         //expr = null;
186                         //return null;
187                     }
188                 }
189                 if (expr.isConstant() || (expr.op == THIS) || (expr.op == SUPER)) {
190                     //System.out.println("FINAL = " + field + " in " + ctx.field);
191                     field.setValue(expr);
192                     field.addModifiers(M_INLINEABLE);
193 
194                     // The two lines below used to elide the declaration
195                     // of inlineable variables, on the theory that there
196                     // wouldn't be any references.  But this breaks the
197                     // translation of nested classes, which might refer to
198                     // the variable.  Fix for 4073244.
199 
200                     //expr = null;
201                     //return null;
202                 }
203             }
204         }
205         return this;
206     }
207 
208     /**
209      * Create a copy of the statement for method inlining
210      */
211     public Statement copyInline(Context ctx, boolean valNeeded) {
212         VarDeclarationStatement s = (VarDeclarationStatement)clone();
213         if (expr != null) {
214             s.expr = expr.copyInline(ctx);
215         }
216         return s;
217     }
218 
219     /**
220      * The cost of inlining this statement
221      */
222     public int costInline(int thresh, Environment env, Context ctx) {
223         if (field != null && field.isInnerClass()) {
224             return thresh;      // don't copy classes...
225         }
226         return (expr != null) ? expr.costInline(thresh, env, ctx) : 0;
227     }
228 
229     /**
230      * Code
231      */
232     public void code(Environment env, Context ctx, Assembler asm) {
233         if (expr != null && !expr.type.isType(TC_VOID)) {
234             // The two lines of code directly following this comment used
235             // to be in the opposite order.  They were switched so that
236             // lines like the following:
237             //
238             //     int j = (j = 4);
239             //
240             // will compile correctly.  (Constructions like the above are
241             // legal.  JLS 14.3.2 says that the scope of a local variable
242             // includes its own initializer.)  It is important that we
243             // declare `field' before we code `expr', because otherwise
244             // situations can arise where `field' thinks it is assigned
245             // a local variable slot that is, in actuality, assigned to
246             // an entirely different variable.  (Bug id 4076729)
247             ctx.declare(env, field);
248             expr.codeValue(env, ctx, asm);
249 
250             asm.add(where, opc_istore + field.getType().getTypeCodeOffset(),
251                     new LocalVariable(field, field.number));
252         } else {
253             ctx.declare(env, field);
254             if (expr != null) {
255                 // an initial side effect, rather than an initial value
256                 expr.code(env, ctx, asm);
257             }
258         }
259     }
260 
261     /**
262      * Print
263      */
264     public void print(PrintStream out, int indent) {
265         out.print("local ");
266         if (field != null) {
267             out.print(field + "#" + field.hashCode());
268             if (expr != null) {
269                 out.print(" = ");
270                 expr.print(out);
271             }
272         } else {
273             expr.print(out);
274             out.print(";");
275         }
276     }
277 }