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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.Label; | |
| 31 | +import sun.tools.asm.TryData; | |
| 32 | +import sun.tools.asm.CatchData; | |
| 33 | +import java.io.PrintStream; | |
| 34 | +import java.util.Enumeration; | |
| 35 | +import java.util.Hashtable; | |
| 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 TryStatement extends Statement { | |
| 44 | + Statement body; | |
| 45 | + Statement args[]; | |
| 46 | + long arrayCloneWhere; // private note posted from MethodExpression | |
| 47 | + | |
| 48 | + /** | |
| 49 | + * Constructor | |
| 50 | + */ | |
| 51 | + public TryStatement(long where, Statement body, Statement args[]) { | |
| 52 | + super(TRY, where); | |
| 53 | + this.body = body; | |
| 54 | + this.args = args; | |
| 55 | + } | |
| 56 | + | |
| 57 | + /** | |
| 58 | + * Check statement | |
| 59 | + */ | |
| 60 | + Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) { | |
| 61 | + checkLabel(env, ctx); | |
| 62 | + try { | |
| 63 | + vset = reach(env, vset); | |
| 64 | + Hashtable newexp = new Hashtable(); | |
| 65 | + CheckContext newctx = new CheckContext(ctx, this); | |
| 66 | + | |
| 67 | + // Check 'try' block. A variable is DA (DU) before the try | |
| 68 | + // block if it is DA (DU) before the try statement. | |
| 69 | + Vset vs = body.check(env, newctx, vset.copy(), newexp); | |
| 70 | + | |
| 71 | + // A variable is DA before a catch block if it is DA before the | |
| 72 | + // try statement. A variable is DU before a catch block if it | |
| 73 | + // is DU after the try block and before any 'break', 'continue', | |
| 74 | + // 'throw', or 'return' contained therein. That is, the variable | |
| 75 | + // is DU upon entry to the try-statement and is not assigned to | |
| 76 | + // anywhere within the try block. | |
| 77 | + Vset cvs = Vset.firstDAandSecondDU(vset, vs.copy().join(newctx.vsTryExit)); | |
| 78 | + | |
| 79 | + for (int i = 0 ; i < args.length ; i++) { | |
| 80 | + // A variable is DA (DU) after a try statement if | |
| 81 | + // it is DA (DU) after every catch block. | |
| 82 | + vs = vs.join(args[i].check(env, newctx, cvs.copy(), exp)); | |
| 83 | + } | |
| 84 | + | |
| 85 | + // Check that catch statements are actually reached | |
| 86 | + for (int i = 1 ; i < args.length ; i++) { | |
| 87 | + CatchStatement cs = (CatchStatement)args[i]; | |
| 88 | + if (cs.field == null) { | |
| 89 | + continue; | |
| 90 | + } | |
| 91 | + Type type = cs.field.getType(); | |
| 92 | + ClassDefinition def = env.getClassDefinition(type); | |
| 93 | + | |
| 94 | + for (int j = 0 ; j < i ; j++) { | |
| 95 | + CatchStatement cs2 = (CatchStatement)args[j]; | |
| 96 | + if (cs2.field == null) { | |
| 97 | + continue; | |
| 98 | + } | |
| 99 | + Type t = cs2.field.getType(); | |
| 100 | + ClassDeclaration c = env.getClassDeclaration(t); | |
| 101 | + if (def.subClassOf(env, c)) { | |
| 102 | + env.error(args[i].where, "catch.not.reached"); | |
| 103 | + break; | |
| 104 | + } | |
| 105 | + } | |
| 106 | + } | |
| 107 | + | |
| 108 | + ClassDeclaration ignore1 = env.getClassDeclaration(idJavaLangError); | |
| 109 | + ClassDeclaration ignore2 = env.getClassDeclaration(idJavaLangRuntimeException); | |
| 110 | + | |
| 111 | + // Make sure the exception is actually throw in that part of the code | |
| 112 | + for (int i = 0 ; i < args.length ; i++) { | |
| 113 | + CatchStatement cs = (CatchStatement)args[i]; | |
| 114 | + if (cs.field == null) { | |
| 115 | + continue; | |
| 116 | + } | |
| 117 | + Type type = cs.field.getType(); | |
| 118 | + if (!type.isType(TC_CLASS)) { | |
| 119 | + // CatchStatement.checkValue() will have already printed | |
| 120 | + // an error message | |
| 121 | + continue; | |
| 122 | + } | |
| 123 | + | |
| 124 | + ClassDefinition def = env.getClassDefinition(type); | |
| 125 | + | |
| 126 | + // Anyone can throw these! | |
| 127 | + if (def.subClassOf(env, ignore1) || def.superClassOf(env, ignore1) || | |
| 128 | + def.subClassOf(env, ignore2) || def.superClassOf(env, ignore2)) { | |
| 129 | + continue; | |
| 130 | + } | |
| 131 | + | |
| 132 | + // Make sure the exception is actually throw in that part of the code | |
| 133 | + boolean ok = false; | |
| 134 | + for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) { | |
| 135 | + ClassDeclaration c = (ClassDeclaration)e.nextElement(); | |
| 136 | + if (def.superClassOf(env, c) || def.subClassOf(env, c)) { | |
| 137 | + ok = true; | |
| 138 | + break; | |
| 139 | + } | |
| 140 | + } | |
| 141 | + if (!ok && arrayCloneWhere != 0 | |
| 142 | + && def.getName().toString().equals("java.lang.CloneNotSupportedException")) { | |
| 143 | + env.error(arrayCloneWhere, "warn.array.clone.supported", def.getName()); | |
| 144 | + } | |
| 145 | + | |
| 146 | + if (!ok) { | |
| 147 | + env.error(cs.where, "catch.not.thrown", def.getName()); | |
| 148 | + } | |
| 149 | + } | |
| 150 | + | |
| 151 | + // Only carry over exceptions that are not caught | |
| 152 | + for (Enumeration e = newexp.keys() ; e.hasMoreElements() ; ) { | |
| 153 | + ClassDeclaration c = (ClassDeclaration)e.nextElement(); | |
| 154 | + ClassDefinition def = c.getClassDefinition(env); | |
| 155 | + boolean add = true; | |
| 156 | + for (int i = 0 ; i < args.length ; i++) { | |
| 157 | + CatchStatement cs = (CatchStatement)args[i]; | |
| 158 | + if (cs.field == null) { | |
| 159 | + continue; | |
| 160 | + } | |
| 161 | + Type type = cs.field.getType(); | |
| 162 | + if (type.isType(TC_ERROR)) | |
| 163 | + continue; | |
| 164 | + if (def.subClassOf(env, env.getClassDeclaration(type))) { | |
| 165 | + add = false; | |
| 166 | + break; | |
| 167 | + } | |
| 168 | + } | |
| 169 | + if (add) { | |
| 170 | + exp.put(c, newexp.get(c)); | |
| 171 | + } | |
| 172 | + } | |
| 173 | + // A variable is DA (DU) after a try statement if it is DA (DU) | |
| 174 | + // after the try block and after every catch block. These variables | |
| 175 | + // are represented by 'vs'. If the try statement is labelled, we | |
| 176 | + // may also exit from it (including from within a catch block) via | |
| 177 | + // a break statement. | |
| 178 | + // If there is a finally block, the Vset returned here is further | |
| 179 | + // adjusted. Note that this 'TryStatement' node will be a child of | |
| 180 | + // a 'FinallyStatement' node in that case. | |
| 181 | + return ctx.removeAdditionalVars(vs.join(newctx.vsBreak)); | |
| 182 | + } catch (ClassNotFound e) { | |
| 183 | + env.error(where, "class.not.found", e.name, opNames[op]); | |
| 184 | + return vset; | |
| 185 | + } | |
| 186 | + } | |
| 187 | + | |
| 188 | + /** | |
| 189 | + * Inline | |
| 190 | + */ | |
| 191 | + public Statement inline(Environment env, Context ctx) { | |
| 192 | + if (body != null) { | |
| 193 | + body = body.inline(env, new Context(ctx, this)); | |
| 194 | + } | |
| 195 | + if (body == null) { | |
| 196 | + return null; | |
| 197 | + } | |
| 198 | + for (int i = 0 ; i < args.length ; i++) { | |
| 199 | + if (args[i] != null) { | |
| 200 | + args[i] = args[i].inline(env, new Context(ctx, this)); | |
| 201 | + } | |
| 202 | + } | |
| 203 | + return (args.length == 0) ? eliminate(env, body) : this; | |
| 204 | + } | |
| 205 | + | |
| 206 | + /** | |
| 207 | + * Create a copy of the statement for method inlining | |
| 208 | + */ | |
| 209 | + public Statement copyInline(Context ctx, boolean valNeeded) { | |
| 210 | + TryStatement s = (TryStatement)clone(); | |
| 211 | + if (body != null) { | |
| 212 | + s.body = body.copyInline(ctx, valNeeded); | |
| 213 | + } | |
| 214 | + s.args = new Statement[args.length]; | |
| 215 | + for (int i = 0 ; i < args.length ; i++) { | |
| 216 | + if (args[i] != null) { | |
| 217 | + s.args[i] = args[i].copyInline(ctx, valNeeded); | |
| 218 | + } | |
| 219 | + } | |
| 220 | + return s; | |
| 221 | + } | |
| 222 | + | |
| 223 | + /** | |
| 224 | + * Compute cost of inlining this statement | |
| 225 | + */ | |
| 226 | + public int costInline(int thresh, Environment env, Context ctx){ | |
| 227 | + | |
| 228 | + // Don't inline methods containing try statements. | |
| 229 | + // If the try statement is being inlined in order to | |
| 230 | + // inline a method that returns a value which is | |
| 231 | + // a subexpression of an expression involving the | |
| 232 | + // operand stack, then the early operands may get lost. | |
| 233 | + // This shows up as a verifier error. For example, | |
| 234 | + // in the following: | |
| 235 | + // | |
| 236 | + // public static int test() { | |
| 237 | + // try { return 2; } catch (Exception e) { return 0; } | |
| 238 | + // } | |
| 239 | + // | |
| 240 | + // System.out.println(test()); | |
| 241 | + // | |
| 242 | + // an inlined call to test() might look like this: | |
| 243 | + // | |
| 244 | + // 0 getstatic <Field java.io.PrintStream out> | |
| 245 | + // 3 iconst_2 | |
| 246 | + // 4 goto 9 | |
| 247 | + // 7 pop | |
| 248 | + // 8 iconst_0 | |
| 249 | + // 9 invokevirtual <Method void println(int)> | |
| 250 | + // 12 return | |
| 251 | + // Exception table: | |
| 252 | + // from to target type | |
| 253 | + // 3 7 7 <Class java.lang.Exception> | |
| 254 | + // | |
| 255 | + // This fails to verify because the operand stored | |
| 256 | + // for System.out gets axed at an exception, leading to | |
| 257 | + // an inconsistent stack depth at pc=7. | |
| 258 | + // | |
| 259 | + // Note that although all code must be able to be inlined | |
| 260 | + // to implement initializers, this problem doesn't come up, | |
| 261 | + // as try statements themselves can never be expressions. | |
| 262 | + // It suffices here to make sure they are never inlined as part | |
| 263 | + // of optimization. | |
| 264 | + | |
| 265 | + return thresh; | |
| 266 | + } | |
| 267 | + | |
| 268 | + /** | |
| 269 | + * Code | |
| 270 | + */ | |
| 271 | + public void code(Environment env, Context ctx, Assembler asm) { | |
| 272 | + CodeContext newctx = new CodeContext(ctx, this); | |
| 273 | + | |
| 274 | + TryData td = new TryData(); | |
| 275 | + for (int i = 0 ; i < args.length ; i++) { | |
| 276 | + Type t = ((CatchStatement)args[i]).field.getType(); | |
| 277 | + if (t.isType(TC_CLASS)) { | |
| 278 | + td.add(env.getClassDeclaration(t)); | |
| 279 | + } else { | |
| 280 | + td.add(t); | |
| 281 | + } | |
| 282 | + } | |
| 283 | + asm.add(where, opc_try, td); | |
| 284 | + if (body != null) { | |
| 285 | + body.code(env, newctx, asm); | |
| 286 | + } | |
| 287 | + | |
| 288 | + asm.add(td.getEndLabel()); | |
| 289 | + asm.add(where, opc_goto, newctx.breakLabel); | |
| 290 | + | |
| 291 | + for (int i = 0 ; i < args.length ; i++) { | |
| 292 | + CatchData cd = td.getCatch(i); | |
| 293 | + asm.add(cd.getLabel()); | |
| 294 | + args[i].code(env, newctx, asm); | |
| 295 | + asm.add(where, opc_goto, newctx.breakLabel); | |
| 296 | + } | |
| 297 | + | |
| 298 | + asm.add(newctx.breakLabel); | |
| 299 | + } | |
| 300 | + | |
| 301 | + /** | |
| 302 | ||
| 303 | + */ | |
| 304 | + public void print(PrintStream out, int indent) { | |
| 305 | + super.print(out, indent); | |
| 306 | + out.print("try "); | |
| 307 | + if (body != null) { | |
| 308 | + body.print(out, indent); | |
| 309 | + } else { | |
| 310 | + out.print("<empty>"); | |
| 311 | + } | |
| 312 | + for (int i = 0 ; i < args.length ; i++) { | |
| 313 | + out.print(" "); | |
| 314 | + args[i].print(out, indent); | |
| 315 | + } | |
| 316 | + } | |
| 317 | +} | |