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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 java.io.PrintStream; | |
| 32 | +import java.util.Hashtable; | |
| 33 | + | |
| 34 | +/** | |
| 35 | + * WARNING: The contents of this source file are not part of any | |
| 36 | + * supported API. Code that depends on them does so at its own risk: | |
| 37 | + * they are subject to change or removal without notice. | |
| 38 | + */ | |
| 39 | +public | |
| 40 | +class Statement extends Node { | |
| 41 | + public static final Vset DEAD_END = Vset.DEAD_END; | |
| 42 | + Identifier labels[] = null; | |
| 43 | + | |
| 44 | + /** | |
| 45 | + * Constructor | |
| 46 | + */ | |
| 47 | + Statement(int op, long where) { | |
| 48 | + super(op, where); | |
| 49 | + } | |
| 50 | + | |
| 51 | + /** | |
| 52 | + * An empty statement. Its costInline is infinite. | |
| 53 | + */ | |
| 54 | + public static final Statement empty = new Statement(STAT, 0); | |
| 55 | + | |
| 56 | + /** | |
| 57 | + * The largest possible interesting inline cost value. | |
| 58 | + */ | |
| 59 | + public static final int MAXINLINECOST = | |
| 60 | + Integer.getInteger("javac.maxinlinecost", | |
| 61 | + 30).intValue(); | |
| 62 | + | |
| 63 | + /** | |
| 64 | + * Insert a bit of code at the front of a statement. | |
| 65 | + * Side-effect s2, if it is a CompoundStatement. | |
| 66 | + */ | |
| 67 | + public static Statement insertStatement(Statement s1, Statement s2) { | |
| 68 | + if (s2 == null) { | |
| 69 | + s2 = s1; | |
| 70 | + } else if (s2 instanceof CompoundStatement) { | |
| 71 | + // Do not add another level of block nesting. | |
| 72 | + ((CompoundStatement)s2).insertStatement(s1); | |
| 73 | + } else { | |
| 74 | + Statement body[] = { s1, s2 }; | |
| 75 | + s2 = new CompoundStatement(s1.getWhere(), body); | |
| 76 | + } | |
| 77 | + return s2; | |
| 78 | + } | |
| 79 | + | |
| 80 | + /** | |
| 81 | + * Set the label of a statement | |
| 82 | + */ | |
| 83 | + public void setLabel(Environment env, Expression e) { | |
| 84 | + if (e.op == IDENT) { | |
| 85 | + if (labels == null) { | |
| 86 | + labels = new Identifier[1]; | |
| 87 | + } else { | |
| 88 | + // this should almost never happen. Multiple labels on | |
| 89 | + // the same statement. But handle it gracefully. | |
| 90 | + Identifier newLabels[] = new Identifier[labels.length + 1]; | |
| 91 | + System.arraycopy(labels, 0, newLabels, 1, labels.length); | |
| 92 | + labels = newLabels; | |
| 93 | + } | |
| 94 | + labels[0] = ((IdentifierExpression)e).id; | |
| 95 | + } else { | |
| 96 | + env.error(e.where, "invalid.label"); | |
| 97 | + } | |
| 98 | + } | |
| 99 | + | |
| 100 | + /** | |
| 101 | + * Check a statement | |
| 102 | + */ | |
| 103 | + public Vset checkMethod(Environment env, Context ctx, Vset vset, Hashtable exp) { | |
| 104 | + // Set up ctx.getReturnContext() for the sake of ReturnStatement.check(). | |
| 105 | + CheckContext mctx = new CheckContext(ctx, new Statement(METHOD, 0)); | |
| 106 | + ctx = mctx; | |
| 107 | + | |
| 108 | + vset = check(env, ctx, vset, exp); | |
| 109 | + | |
| 110 | + // Check for return | |
| 111 | + if (!ctx.field.getType().getReturnType().isType(TC_VOID)) { | |
| 112 | + // In general, we suppress further error messages due to | |
| 113 | + // unreachable statements after reporting the first error | |
| 114 | + // along a flow path (using 'clearDeadEnd'). Here, we | |
| 115 | + // report an error anyway, because the end of the method | |
| 116 | + // should be unreachable despite the earlier error. The | |
| 117 | + // difference in treatment is due to the fact that, in this | |
| 118 | + // case, the error is reachability, not unreachability. | |
| 119 | + // NOTE: In addition to this subtle difference in the quality | |
| 120 | + // of the error diagnostics, this treatment is essential to | |
| 121 | + // preserve the correctness of using 'clearDeadEnd' to implement | |
| 122 | + // the special-case reachability rules for if-then and if-then-else. | |
| 123 | + if (!vset.isDeadEnd()) { | |
| 124 | + env.error(ctx.field.getWhere(), "return.required.at.end", ctx.field); | |
| 125 | + } | |
| 126 | + } | |
| 127 | + | |
| 128 | + // Simulate a return at the end. | |
| 129 | + vset = vset.join(mctx.vsBreak); | |
| 130 | + | |
| 131 | + return vset; | |
| 132 | + } | |
| 133 | + Vset checkDeclaration(Environment env, Context ctx, Vset vset, int mod, Type t, Hashtable exp) { | |
| 134 | + throw new CompilerError("checkDeclaration"); | |
| 135 | + } | |
| 136 | + | |
| 137 | + /** | |
| 138 | + * Make sure the labels on this statement do not duplicate the | |
| 139 | + * labels on any enclosing statement. Provided as a convenience | |
| 140 | + * for subclasses. | |
| 141 | + */ | |
| 142 | + protected void checkLabel(Environment env, Context ctx) { | |
| 143 | + if (labels != null) { | |
| 144 | + loop: for (int i = 0; i < labels.length; i++) { | |
| 145 | + // Make sure there is not a double label on this statement. | |
| 146 | + for (int j = i+1; j < labels.length; j++) { | |
| 147 | + if (labels[i] == labels[j]) { | |
| 148 | + env.error(where, "nested.duplicate.label", labels[i]); | |
| 149 | + continue loop; | |
| 150 | + } | |
| 151 | + } | |
| 152 | + | |
| 153 | + // Make sure no enclosing statement has the same label. | |
| 154 | + CheckContext destCtx = | |
| 155 | + (CheckContext) ctx.getLabelContext(labels[i]); | |
| 156 | + | |
| 157 | + if (destCtx != null) { | |
| 158 | + // Check to make sure the label is in not uplevel. | |
| 159 | + if (destCtx.frameNumber == ctx.frameNumber) { | |
| 160 | + env.error(where, "nested.duplicate.label", labels[i]); | |
| 161 | + } | |
| 162 | + } | |
| 163 | + } // end loop | |
| 164 | + } | |
| 165 | + } | |
| 166 | + | |
| 167 | + Vset check(Environment env, Context ctx, Vset vset, Hashtable exp) { | |
| 168 | + throw new CompilerError("check"); | |
| 169 | + } | |
| 170 | + | |
| 171 | + /** This is called in contexts where declarations are valid. */ | |
| 172 | + Vset checkBlockStatement(Environment env, Context ctx, Vset vset, Hashtable exp) { | |
| 173 | + return check(env, ctx, vset, exp); | |
| 174 | + } | |
| 175 | + | |
| 176 | + Vset reach(Environment env, Vset vset) { | |
| 177 | + if (vset.isDeadEnd()) { | |
| 178 | + env.error(where, "stat.not.reached"); | |
| 179 | + vset = vset.clearDeadEnd(); | |
| 180 | + } | |
| 181 | + return vset; | |
| 182 | + } | |
| 183 | + | |
| 184 | + /** | |
| 185 | + * Inline | |
| 186 | + */ | |
| 187 | + public Statement inline(Environment env, Context ctx) { | |
| 188 | + return this; | |
| 189 | + } | |
| 190 | + | |
| 191 | + /** | |
| 192 | + * Eliminate this statement, which is only possible if it has no label. | |
| 193 | + */ | |
| 194 | + public Statement eliminate(Environment env, Statement s) { | |
| 195 | + if ((s != null) && (labels != null)) { | |
| 196 | + Statement args[] = {s}; | |
| 197 | + s = new CompoundStatement(where, args); | |
| 198 | + s.labels = labels; | |
| 199 | + } | |
| 200 | + return s; | |
| 201 | + } | |
| 202 | + | |
| 203 | + | |
| 204 | + /** | |
| 205 | + * Code | |
| 206 | + */ | |
| 207 | + public void code(Environment env, Context ctx, Assembler asm) { | |
| 208 | + throw new CompilerError("code"); | |
| 209 | + } | |
| 210 | + | |
| 211 | + /** | |
| 212 | + * Generate the code to call all finally's for a break, continue, or | |
| 213 | + * return statement. We must call "jsr" on all the cleanup code between | |
| 214 | + * the current context "ctx", and the destination context "stopctx". | |
| 215 | + * If 'save' isn't null, there is also a value on the top of the stack | |
| 216 | + */ | |
| 217 | + void codeFinally(Environment env, Context ctx, Assembler asm, | |
| 218 | + Context stopctx, Type save) { | |
| 219 | + Integer num = null; | |
| 220 | + boolean haveCleanup = false; // there is a finally or synchronize; | |
| 221 | + boolean haveNonLocalFinally = false; // some finally doesn't return; | |
| 222 | + | |
| 223 | + for (Context c = ctx; (c != null) && (c != stopctx); c = c.prev) { | |
| 224 | + if (c.node == null) | |
| 225 | + continue; | |
| 226 | + if (c.node.op == SYNCHRONIZED) { | |
| 227 | + haveCleanup = true; | |
| 228 | + } else if (c.node.op == FINALLY | |
| 229 | + && ((CodeContext)c).contLabel != null) { | |
| 230 | + // c.contLabel == null indicates we're in the "finally" part | |
| 231 | + haveCleanup = true; | |
| 232 | + FinallyStatement st = ((FinallyStatement)(c.node)); | |
| 233 | + if (!st.finallyCanFinish) { | |
| 234 | + haveNonLocalFinally = true; | |
| 235 | + // after hitting a non-local finally, no need generating | |
| 236 | + // further code, because it won't get executed. | |
| 237 | + break; | |
| 238 | + } | |
| 239 | + } | |
| 240 | + } | |
| 241 | + if (!haveCleanup) { | |
| 242 | + // there is no cleanup that needs to be done. Just quit. | |
| 243 | + return; | |
| 244 | + } | |
| 245 | + if (save != null) { | |
| 246 | + // This statement has a return value on the stack. | |
| 247 | + ClassDefinition def = ctx.field.getClassDefinition(); | |
| 248 | + if (!haveNonLocalFinally) { | |
| 249 | + // Save the return value in the register which should have | |
| 250 | + // been reserved. | |
| 251 | + LocalMember lf = ctx.getLocalField(idFinallyReturnValue); | |
| 252 | + num = new Integer(lf.number); | |
| 253 | + asm.add(where, opc_istore + save.getTypeCodeOffset(), num); | |
| 254 | + } else { | |
| 255 | + // Pop the return value. | |
| 256 | + switch(ctx.field.getType().getReturnType().getTypeCode()) { | |
| 257 | + case TC_VOID: | |
| 258 | + break; | |
| 259 | + case TC_DOUBLE: case TC_LONG: | |
| 260 | + asm.add(where, opc_pop2); break; | |
| 261 | + default: | |
| 262 | + asm.add(where, opc_pop); break; | |
| 263 | + } | |
| 264 | + } | |
| 265 | + } | |
| 266 | + // Call each of the cleanup functions, as necessary. | |
| 267 | + for (Context c = ctx ; (c != null) && (c != stopctx) ; c = c.prev) { | |
| 268 | + if (c.node == null) | |
| 269 | + continue; | |
| 270 | + if (c.node.op == SYNCHRONIZED) { | |
| 271 | + asm.add(where, opc_jsr, ((CodeContext)c).contLabel); | |
| 272 | + } else if (c.node.op == FINALLY | |
| 273 | + && ((CodeContext)c).contLabel != null) { | |
| 274 | + FinallyStatement st = ((FinallyStatement)(c.node)); | |
| 275 | + Label label = ((CodeContext)c).contLabel; | |
| 276 | + if (st.finallyCanFinish) { | |
| 277 | + asm.add(where, opc_jsr, label); | |
| 278 | + } else { | |
| 279 | + // the code never returns, so we're done. | |
| 280 | + asm.add(where, opc_goto, label); | |
| 281 | + break; | |
| 282 | + } | |
| 283 | + } | |
| 284 | + } | |
| 285 | + // Move the return value from the register back to the stack. | |
| 286 | + if (num != null) { | |
| 287 | + asm.add(where, opc_iload + save.getTypeCodeOffset(), num); | |
| 288 | + } | |
| 289 | + } | |
| 290 | + | |
| 291 | + /* | |
| 292 | + * Return true if the statement has the given label | |
| 293 | + */ | |
| 294 | + public boolean hasLabel (Identifier lbl) { | |
| 295 | + Identifier labels[] = this.labels; | |
| 296 | + if (labels != null) { | |
| 297 | + for (int i = labels.length; --i >= 0; ) { | |
| 298 | + if (labels[i].equals(lbl)) { | |
| 299 | + return true; | |
| 300 | + } | |
| 301 | + } | |
| 302 | + } | |
| 303 | + return false; | |
| 304 | + } | |
| 305 | + | |
| 306 | + /** | |
| 307 | + * Check if the first thing is a constructor invocation | |
| 308 | + */ | |
| 309 | + public Expression firstConstructor() { | |
| 310 | + return null; | |
| 311 | + } | |
| 312 | + | |
| 313 | + /** | |
| 314 | + * Create a copy of the statement for method inlining | |
| 315 | + */ | |
| 316 | + public Statement copyInline(Context ctx, boolean valNeeded) { | |
| 317 | + return (Statement)clone(); | |
| 318 | + } | |
| 319 | + | |
| 320 | + public int costInline(int thresh, Environment env, Context ctx) { | |
| 321 | + return thresh; | |
| 322 | + } | |
| 323 | + | |
| 324 | + | |
| 325 | + /** | |
| 326 | ||
| 327 | + */ | |
| 328 | + void printIndent(PrintStream out, int indent) { | |
| 329 | + for (int i = 0 ; i < indent ; i++) { | |
| 330 | + out.print(" "); | |
| 331 | + } | |
| 332 | + } | |
| 333 | + public void print(PrintStream out, int indent) { | |
| 334 | + if (labels != null) { | |
| 335 | + for (int i = labels.length; --i >= 0; ) | |
| 336 | + out.print(labels[i] + ": "); | |
| 337 | + } | |
| 338 | + } | |
| 339 | + public void print(PrintStream out) { | |
| 340 | + print(out, 0); | |
| 341 | + } | |
| 342 | +} | |