J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1994-2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any 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 | * Print |
| 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 | } |