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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 | } | ||