1 /*
2 * Copyright (c) 1994, 2004, 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.Label;
31 import sun.tools.asm.TryData;
32 import sun.tools.asm.CatchData;
33 import java.io.PrintStream;
34 import java.util.Hashtable;
35 import java.util.Enumeration;
36
37 /**
38 * WARNING: The contents of this source file are not part of any
39 * supported API. Code that depends on them does so at its own risk:
40 * they are subject to change or removal without notice.
41 */
42 public
43 class FinallyStatement extends Statement {
44 Statement body;
45 Statement finalbody;
46 boolean finallyCanFinish; // does finalBody never return?
47 boolean needReturnSlot; // set by inner return statement
48 Statement init; // try object expression or declaration from parser
49 LocalMember tryTemp; // temp holding the try object, if any
50
51 /**
52 * Constructor
53 */
54 public FinallyStatement(long where, Statement body, Statement finalbody) {
55 super(FINALLY, where);
56 this.body = body;
57 this.finalbody = finalbody;
58 }
59
60 // /**
61 // * Constructor for try (init) {body}
62 // */
63 // public FinallyStatement(long where, Statement init, Statement body, int junk) {
64 // this(where, body, null);
65 // this.init = init;
66 // }
67
68 /**
69 * Check statement
70 */
71 Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) {
72 vset = reach(env, vset);
73 Hashtable newexp = new Hashtable();
74
75 // Handle the proposed 'try (init) { stmts } finally { stmts }' syntax.
76 // This feature has not been adopted, and support is presently disabled.
77 /*-----------------------------------------------------------*
78 if (init != null) {
79 ClassDefinition sourceClass = ctx.field.getClassDefinition();
80 Expression tryExpr = null;
81 DeclarationStatement tryDecl = null;
82 long where = init.getWhere();
83 // find out whether init is a simple expression or a declaration
84 if (init.getOp() == EXPRESSION) {
85 tryExpr = ((ExpressionStatement)init).expr;
86 init = null; // restore it below
87 vset = tryExpr.checkValue(env, ctx, vset, exp);
88 } else if (init.getOp() == DECLARATION) {
89 tryDecl = (DeclarationStatement) init;
90 init = null; // restore it below
91 vset = tryDecl.checkBlockStatement(env, ctx, vset, exp);
92 if (tryDecl.args.length != 1) {
93 env.error(where, "invalid.decl");
94 } else {
95 LocalMember field =
96 ((VarDeclarationStatement) tryDecl.args[0]).field;
97 tryExpr = new IdentifierExpression(where, field);
98 tryExpr.type = field.getType();
99 }
100 } else {
101 env.error(where, "invalid.expr");
102 vset = init.check(env, ctx, vset, exp);
103 }
104 Type type = (tryExpr == null) ? Type.tError : tryExpr.getType();
105
106 MemberDefinition tryEnter = null;
107 MemberDefinition tryExit = null;
108 if (!type.isType(TC_CLASS)) {
109 if (!type.isType(TC_ERROR)) {
110 env.error(where, "invalid.method.invoke", type);
111 }
112 } else {
113 Identifier idTryEnter = Identifier.lookup("tryEnter");
114 Identifier idTryExit = Identifier.lookup("tryExit");
115 Type tTryMethod = Type.tMethod(Type.tVoid);
116 try {
117 ClassDefinition tryClass = env.getClassDefinition(type);
118 tryEnter = tryClass.matchMethod(env, sourceClass, idTryEnter);
119 tryExit = tryClass.matchMethod(env, sourceClass, idTryExit);
120 if (tryEnter != null && !tryEnter.getType().equals(tTryMethod)) {
121 tryEnter = null;
122 }
123 if (tryExit != null && !tryExit.getType().equals(tTryMethod)) {
124 tryExit = null;
125 }
126 } catch (ClassNotFound ee) {
127 env.error(where, "class.not.found", ee.name, ctx.field);
128 } catch (AmbiguousMember ee) {
129 Identifier id = ee.field1.getName();
130 env.error(where, "ambig.field", id, ee.field1, ee.field2);
131 }
132 }
133 if (tryEnter == null || tryExit == null) {
134 // Make a better (more didactic) error here!
135 env.error(where, "invalid.method.invoke", type);
136 } else {
137 tryTemp = new LocalMember(where, sourceClass, 0,
138 type, Identifier.lookup("<try_object>"));
139 ctx = new Context(ctx, this);
140 ctx.declare(env, tryTemp);
141
142 Expression e;
143 e = new IdentifierExpression(where, tryTemp);
144 e = new AssignExpression(where, e, tryExpr);
145 e = new MethodExpression(where, e, tryEnter, new Expression[0]);
146 e.type = Type.tVoid;
147 Statement enterCall = new ExpressionStatement(where, e);
148 // store it on the init, for code generation
149 if (tryDecl != null) {
150 Statement args2[] = { tryDecl.args[0], enterCall };
151 tryDecl.args = args2;
152 init = tryDecl;
153 } else {
154 init = enterCall;
155 }
156 e = new IdentifierExpression(where, tryTemp);
157 e = new MethodExpression(where, e, tryExit, new Expression[0]);
158 e.type = Type.tVoid;
159 Statement exitCall = new ExpressionStatement(where, e);
160 finalbody = exitCall;
161 }
162 }
163 *-----------------------------------------------------------*/
164
165 // Check the try part. We reach the end of the try part either by
166 // finishing normally, or doing a break to the label of the try/finally.
167 // NOTE: I don't think newctx1.vsBreak is ever used -- see TryStatement.
168 CheckContext newctx1 = new CheckContext(ctx, this);
169 Vset vset1 = body.check(env, newctx1, vset.copy(), newexp)
170 .join(newctx1.vsBreak);
171 // Check the finally part.
172 CheckContext newctx2 = new CheckContext(ctx, this);
173 // Should never access this field. The null indicates the finally part.
174 newctx2.vsContinue = null;
175 Vset vset2 = finalbody.check(env, newctx2, vset, exp);
176 finallyCanFinish = !vset2.isDeadEnd();
177 vset2 = vset2.join(newctx2.vsBreak);
178 // If !finallyCanFinish, then the only possible exceptions that can
179 // occur at this point are the ones preceding the try/finally, or
180 // the ones generated by the finally. Anything in the try is
181 // irrelevant. Otherwise, we have to merge in all the exceptions
182 // generated by the body into exp.
183 if (finallyCanFinish) {
184 // Add newexp's back into exp; cf. ThrowStatement.check().
185 for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) {
186 Object def = e.nextElement();
187 exp.put(def, newexp.get(def));
188 }
189 }
190 return ctx.removeAdditionalVars(vset1.addDAandJoinDU(vset2));
191 }
192
193 /**
194 * Inline
195 */
196 public Statement inline(Environment env, Context ctx) {
197 if (tryTemp != null) {
198 ctx = new Context(ctx, this);
199 ctx.declare(env, tryTemp);
200 }
201 if (init != null) {
202 init = init.inline(env, ctx);
203 }
204 if (body != null) {
205 body = body.inline(env, ctx);
206 }
207 if (finalbody != null) {
208 finalbody = finalbody.inline(env, ctx);
209 }
210 if (body == null) {
211 return eliminate(env, finalbody);
212 }
213 if (finalbody == null) {
214 return eliminate(env, body);
215 }
216 return this;
217 }
218
219 /**
220 * Create a copy of the statement for method inlining
221 */
222 public Statement copyInline(Context ctx, boolean valNeeded) {
223 FinallyStatement s = (FinallyStatement)clone();
224 if (tryTemp != null) {
225 s.tryTemp = tryTemp.copyInline(ctx);
226 }
227 if (init != null) {
228 s.init = init.copyInline(ctx, valNeeded);
229 }
230 if (body != null) {
231 s.body = body.copyInline(ctx, valNeeded);
232 }
233 if (finalbody != null) {
234 s.finalbody = finalbody.copyInline(ctx, valNeeded);
235 }
236 return s;
237 }
238
239 /**
240 * Compute cost of inlining this statement
241 */
242 public int costInline(int thresh, Environment env, Context ctx){
243 int cost = 4;
244 if (init != null) {
245 cost += init.costInline(thresh, env,ctx);
246 if (cost >= thresh) return cost;
247 }
248 if (body != null) {
249 cost += body.costInline(thresh, env,ctx);
250 if (cost >= thresh) return cost;
251 }
252 if (finalbody != null) {
253 cost += finalbody.costInline(thresh, env,ctx);
254 }
255 return cost;
256 }
257
258 /**
259 * Code
260 */
261 public void code(Environment env, Context ctx, Assembler asm) {
262 ctx = new Context(ctx);
263 Integer num1 = null, num2 = null;
264 Label endLabel = new Label();
265
266 if (tryTemp != null) {
267 ctx.declare(env, tryTemp);
268 }
269 if (init != null) {
270 CodeContext exprctx = new CodeContext(ctx, this);
271 init.code(env, exprctx, asm);
272 }
273
274 if (finallyCanFinish) {
275 LocalMember f1, f2;
276 ClassDefinition thisClass = ctx.field.getClassDefinition();
277
278 if (needReturnSlot) {
279 Type returnType = ctx.field.getType().getReturnType();
280 LocalMember localfield = new LocalMember(0, thisClass, 0,
281 returnType,
282 idFinallyReturnValue);
283 ctx.declare(env, localfield);
284 env.debugOutput("Assigning return slot to " + localfield.number);
285 }
286
287 // allocate space for the exception and return address
288 f1 = new LocalMember(where, thisClass, 0, Type.tObject, null);
289 f2 = new LocalMember(where, thisClass, 0, Type.tInt, null);
290 num1 = new Integer(ctx.declare(env, f1));
291 num2 = new Integer(ctx.declare(env, f2));
292 }
293
294 TryData td = new TryData();
295 td.add(null);
296
297 // Main body
298 CodeContext bodyctx = new CodeContext(ctx, this);
299 asm.add(where, opc_try, td); // start of protected code
300 body.code(env, bodyctx, asm);
301 asm.add(bodyctx.breakLabel);
302 asm.add(td.getEndLabel()); // end of protected code
303
304 // Cleanup afer body
305 if (finallyCanFinish) {
306 asm.add(where, opc_jsr, bodyctx.contLabel);
307 asm.add(where, opc_goto, endLabel);
308 } else {
309 // just goto the cleanup code. It will never return.
310 asm.add(where, opc_goto, bodyctx.contLabel);
311 }
312
313 // Catch code
314 CatchData cd = td.getCatch(0);
315 asm.add(cd.getLabel());
316 if (finallyCanFinish) {
317 asm.add(where, opc_astore, num1); // store exception
318 asm.add(where, opc_jsr, bodyctx.contLabel);
319 asm.add(where, opc_aload, num1); // rethrow exception
320 asm.add(where, opc_athrow);
321 } else {
322 // pop exception off stack. Fall through to finally code
323 asm.add(where, opc_pop);
324 }
325
326 // The finally part, which is marked by the contLabel. Update
327 // breakLabel: since break's in the finally are different
328 // contLabel: to null to indicate no longer in the protected code.
329 asm.add(bodyctx.contLabel);
330 bodyctx.contLabel = null;
331 bodyctx.breakLabel = endLabel;
332 if (finallyCanFinish) {
333 asm.add(where, opc_astore, num2); // save the return address
334 finalbody.code(env, bodyctx, asm); // execute the cleanup code
335 asm.add(where, opc_ret, num2); // return
336 } else {
337 finalbody.code(env, bodyctx, asm); // execute the cleanup code
338 }
339 asm.add(endLabel); // breaks come here
340 }
341
342 /**
343 * Print
344 */
345 public void print(PrintStream out, int indent) {
346 super.print(out, indent);
347 out.print("try ");
348 if (body != null) {
349 body.print(out, indent);
350 } else {
351 out.print("<empty>");
352 }
353 out.print(" finally ");
354 if (finalbody != null) {
355 finalbody.print(out, indent);
356 } else {
357 out.print("<empty>");
358 }
359 }
360 }