1 /*
2  * Copyright (c) 1994, 2014, 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
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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
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19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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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.Label;
31 import sun.tools.asm.TryData;
32 import sun.tools.asm.CatchData;
33 import java.io.PrintStream;
34 import java.util.Hashtable;
35 
36 /**
37  * WARNING: The contents of this source file are not part of any
38  * supported API.  Code that depends on them does so at its own risk:
39  * they are subject to change or removal without notice.
40  */
41 public
42 class SynchronizedStatement extends Statement {
43     Expression expr;
44     Statement body;
45     boolean needReturnSlot;   // set by inner return statement
46 
47     /**
48      * Constructor
49      */
SynchronizedStatement(long where, Expression expr, Statement body)50     public SynchronizedStatement(long where, Expression expr, Statement body) {
51         super(SYNCHRONIZED, where);
52         this.expr = expr;
53         this.body = body;
54     }
55 
56     /**
57      * Check statement
58      */
check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp)59     Vset check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) {
60         checkLabel(env, ctx);
61         CheckContext newctx = new CheckContext(ctx, this);
62         vset = reach(env, vset);
63         vset = expr.checkValue(env, newctx, vset, exp);
64         if (expr.type.equals(Type.tNull)) {
65             env.error(expr.where, "synchronized.null");
66         }
67         expr = convert(env, newctx, Type.tClass(idJavaLangObject), expr);
68         vset = body.check(env, newctx, vset, exp);
69         return ctx.removeAdditionalVars(vset.join(newctx.vsBreak));
70     }
71 
72     /**
73      * Inline
74      */
inline(Environment env, Context ctx)75     public Statement inline(Environment env, Context ctx) {
76         if (body != null) {
77             body = body.inline(env, ctx);
78         }
79         expr = expr.inlineValue(env, ctx);
80         return this;
81     }
82 
83     /**
84      * Create a copy of the statement for method inlining
85      */
copyInline(Context ctx, boolean valNeeded)86     public Statement copyInline(Context ctx, boolean valNeeded) {
87         SynchronizedStatement s = (SynchronizedStatement)clone();
88         s.expr = expr.copyInline(ctx);
89         if (body != null) {
90             s.body = body.copyInline(ctx, valNeeded);
91         }
92         return s;
93     }
94 
95     /**
96      * Compute cost of inlining this statement
97      */
costInline(int thresh, Environment env, Context ctx)98     public int costInline(int thresh, Environment env, Context ctx){
99         int cost = 1;
100         if (expr != null) {
101             cost += expr.costInline(thresh, env,ctx);
102             if (cost >= thresh) return cost;
103         }
104         if (body != null) {
105             cost += body.costInline(thresh, env,ctx);
106         }
107         return cost;
108     }
109 
110     /**
111      * Code
112      */
code(Environment env, Context ctx, Assembler asm)113     public void code(Environment env, Context ctx, Assembler asm) {
114         ClassDefinition clazz = ctx.field.getClassDefinition();
115         expr.codeValue(env, ctx, asm);
116         ctx = new Context(ctx);
117 
118         if (needReturnSlot) {
119             Type returnType = ctx.field.getType().getReturnType();
120             LocalMember localfield = new LocalMember(0, clazz, 0, returnType,
121                                                    idFinallyReturnValue);
122             ctx.declare(env, localfield);
123             Environment.debugOutput("Assigning return slot to " + localfield.number);
124         }
125 
126         LocalMember f1 = new LocalMember(where, clazz, 0, Type.tObject, null);
127         LocalMember f2 = new LocalMember(where, clazz, 0, Type.tInt, null);
128         Integer num1 = ctx.declare(env, f1);
129         Integer num2 = ctx.declare(env, f2);
130 
131         Label endLabel = new Label();
132 
133         TryData td = new TryData();
134         td.add(null);
135 
136         // lock the object
137         asm.add(where, opc_astore, num1);
138         asm.add(where, opc_aload, num1);
139         asm.add(where, opc_monitorenter);
140 
141         // Main body
142         CodeContext bodyctx = new CodeContext(ctx, this);
143         asm.add(where, opc_try, td);
144         if (body != null) {
145             body.code(env, bodyctx, asm);
146         } else {
147             asm.add(where, opc_nop);
148         }
149         asm.add(bodyctx.breakLabel);
150         asm.add(td.getEndLabel());
151 
152         // Cleanup afer body
153         asm.add(where, opc_aload, num1);
154         asm.add(where, opc_monitorexit);
155         asm.add(where, opc_goto, endLabel);
156 
157         // Catch code
158         CatchData cd = td.getCatch(0);
159         asm.add(cd.getLabel());
160         asm.add(where, opc_aload, num1);
161         asm.add(where, opc_monitorexit);
162         asm.add(where, opc_athrow);
163 
164         // Final body
165         asm.add(bodyctx.contLabel);
166         asm.add(where, opc_astore, num2);
167         asm.add(where, opc_aload, num1);
168         asm.add(where, opc_monitorexit);
169         asm.add(where, opc_ret, num2);
170 
171         asm.add(endLabel);
172     }
173 
174     /**
175      * Print
176      */
print(PrintStream out, int indent)177     public void print(PrintStream out, int indent) {
178         super.print(out, indent);
179         out.print("synchronized ");
180         expr.print(out);
181         out.print(" ");
182         if (body != null) {
183             body.print(out, indent);
184         } else {
185             out.print("{}");
186         }
187     }
188 }
189