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| 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 | ||
| 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 | +} | |