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| 1 | /* | ||
| 2 | * Copyright (c) 1997, 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.tree.*; | ||
| 30 | import sun.tools.asm.Assembler; | ||
| 31 | |||
| 32 | /** | ||
| 33 | * A reference from one scope to another. | ||
| 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 | */ | ||
| 40 | |||
| 41 | public | ||
| 42 | class UplevelReference implements Constants { | ||
| 43 | /** | ||
| 44 | * The class in which the reference occurs. | ||
| 45 | */ | ||
| 46 | ClassDefinition client; | ||
| 47 | |||
| 48 | /** | ||
| 49 | * The field being referenced. | ||
| 50 | * It is always a final argument or a final local variable. | ||
| 51 | * (An uplevel reference to a field of a class C is fetched | ||
| 52 | * through an implicit uplevel reference to C.this, which is | ||
| 53 | * an argument.) | ||
| 54 | */ | ||
| 55 | LocalMember target; | ||
| 56 | |||
| 57 | /** | ||
| 58 | * The local variable which bears a copy of the target's value, | ||
| 59 | * for all methods of the client class. | ||
| 60 | * Its name is "this$C" for <code>this.C</code> or | ||
| 61 | * "val$x" for other target variables <code>x</code>. | ||
| 62 | * <p> | ||
| 63 | * This local variable is always a constructor argument, | ||
| 64 | * and is therefore usable only in the constructor and in initializers. | ||
| 65 | * All other methods use the local field. | ||
| 66 | * @see #localField | ||
| 67 | */ | ||
| 68 | LocalMember localArgument; | ||
| 69 | |||
| 70 | /** | ||
| 71 | * A private synthetic field of the client class which | ||
| 72 | * bears a copy of the target's value. | ||
| 73 | * The compiler tries to avoid creating it if possible. | ||
| 74 | * The field has the same name and type as the localArgument. | ||
| 75 | * @see #localArgument | ||
| 76 | */ | ||
| 77 | MemberDefinition localField; | ||
| 78 | |||
| 79 | /** | ||
| 80 | * The next item on the references list of the client. | ||
| 81 | */ | ||
| 82 | UplevelReference next; | ||
| 83 | |||
| 84 | /** | ||
| 85 | * constructor | ||
| 86 | */ | ||
| 87 | public UplevelReference(ClassDefinition client, LocalMember target) { | ||
| 88 | this.client = client; | ||
| 89 | this.target = target; | ||
| 90 | |||
| 91 | // Choose a name and build a variable declaration node. | ||
| 92 | Identifier valName; | ||
| 93 | if (target.getName().equals(idThis)) { | ||
| 94 | ClassDefinition tc = target.getClassDefinition(); | ||
| 95 | // It should always be true that tc.enclosingClassOf(client). | ||
| 96 | // If it were false, the numbering scheme would fail | ||
| 97 | // to produce unique names, since we'd be trying | ||
| 98 | // to number classes which were not in the sequence | ||
| 99 | // of enclosing scopes. The next paragraph of this | ||
| 100 | // code robustly deals with that possibility, however, | ||
| 101 | // by detecting name collisions and perturbing the names. | ||
| 102 | int depth = 0; | ||
| 103 | for (ClassDefinition pd = tc; !pd.isTopLevel(); pd = pd.getOuterClass()) { | ||
| 104 | // The inner classes specification states that the name of | ||
| 105 | // a private field containing a reference to the outermost | ||
| 106 | // enclosing instance is named "this$0". That outermost | ||
| 107 | // enclosing instance is always the innermost toplevel class. | ||
| 108 | depth += 1; | ||
| 109 | } | ||
| 110 | // In this example, T1,T2,T3 are all top-level (static), | ||
| 111 | // while I4,I5,I6,I7 are all inner. Each of the inner classes | ||
| 112 | // will have a single up-level "this$N" reference to the next | ||
| 113 | // class out. Only the outermost "this$0" will refer to a | ||
| 114 | // top-level class, T3. | ||
| 115 | // | ||
| 116 | // class T1 { | ||
| 117 | // static class T2 { | ||
| 118 | // static class T3 { | ||
| 119 | // class I4 { | ||
| 120 | // class I5 { | ||
| 121 | // class I6 { | ||
| 122 | // // at this point we have these fields in various places: | ||
| 123 | // // I4 this$0; I5 this$1; I6 this$2; | ||
| 124 | // } | ||
| 125 | // } | ||
| 126 | // class I7 { | ||
| 127 | // // I4 this$0; I7 this$1; | ||
| 128 | // } | ||
| 129 | // } | ||
| 130 | // } | ||
| 131 | // } | ||
| 132 | // } | ||
| 133 | valName = Identifier.lookup(prefixThis + depth); | ||
| 134 | } else { | ||
| 135 | valName = Identifier.lookup(prefixVal + target.getName()); | ||
| 136 | } | ||
| 137 | |||
| 138 | // Make reasonably certain that valName is unique to this client. | ||
| 139 | // (This check can be fooled by malicious naming of explicit | ||
| 140 | // constructor arguments, or of inherited fields.) | ||
| 141 | Identifier base = valName; | ||
| 142 | int tick = 0; | ||
| 143 | while (true) { | ||
| 144 | boolean failed = (client.getFirstMatch(valName) != null); | ||
| 145 | for (UplevelReference r = client.getReferences(); | ||
| 146 | r != null; r = r.next) { | ||
| 147 | if (r.target.getName().equals(valName)) { | ||
| 148 | failed = true; | ||
| 149 | } | ||
| 150 | } | ||
| 151 | if (!failed) { | ||
| 152 | break; | ||
| 153 | } | ||
| 154 | // try another name | ||
| 155 | valName = Identifier.lookup(base + "$" + (++tick)); | ||
| 156 | } | ||
| 157 | |||
| 158 | // Build the constructor argument. | ||
| 159 | // Like "this", it wil be shared equally by all constructors of client. | ||
| 160 | localArgument = new LocalMember(target.getWhere(), | ||
| 161 | client, | ||
| 162 | M_FINAL | M_SYNTHETIC, | ||
| 163 | target.getType(), | ||
| 164 | valName); | ||
| 165 | } | ||
| 166 | |||
| 167 | /** | ||
| 168 | * Insert self into a list of references. | ||
| 169 | * Maintain "isEarlierThan" as an invariant of the list. | ||
| 170 | * This is important (a) to maximize stability of signatures, | ||
| 171 | * and (b) to allow uplevel "this" parameters to come at the | ||
| 172 | * front of every argument list they appear in. | ||
| 173 | */ | ||
| 174 | public UplevelReference insertInto(UplevelReference references) { | ||
| 175 | if (references == null || isEarlierThan(references)) { | ||
| 176 | next = references; | ||
| 177 | return this; | ||
| 178 | } else { | ||
| 179 | UplevelReference prev = references; | ||
| 180 | while (!(prev.next == null || isEarlierThan(prev.next))) { | ||
| 181 | prev = prev.next; | ||
| 182 | } | ||
| 183 | next = prev.next; | ||
| 184 | prev.next = this; | ||
| 185 | return references; | ||
| 186 | } | ||
| 187 | } | ||
| 188 | |||
| 189 | /** | ||
| 190 | * Tells if self precedes the other in the canonical ordering. | ||
| 191 | */ | ||
| 192 | public final boolean isEarlierThan(UplevelReference other) { | ||
| 193 | // Outer fields always come first. | ||
| 194 | if (isClientOuterField()) { | ||
| 195 | return true; | ||
| 196 | } else if (other.isClientOuterField()) { | ||
| 197 | return false; | ||
| 198 | } | ||
| 199 | |||
| 200 | // Now it doesn't matter what the order is; use string comparison. | ||
| 201 | LocalMember target2 = other.target; | ||
| 202 | Identifier name = target.getName(); | ||
| 203 | Identifier name2 = target2.getName(); | ||
| 204 | int cmp = name.toString().compareTo(name2.toString()); | ||
| 205 | if (cmp != 0) { | ||
| 206 | return cmp < 0; | ||
| 207 | } | ||
| 208 | Identifier cname = target.getClassDefinition().getName(); | ||
| 209 | Identifier cname2 = target2.getClassDefinition().getName(); | ||
| 210 | int ccmp = cname.toString().compareTo(cname2.toString()); | ||
| 211 | return ccmp < 0; | ||
| 212 | } | ||
| 213 | |||
| 214 | /** | ||
| 215 | * the target of this reference | ||
| 216 | */ | ||
| 217 | public final LocalMember getTarget() { | ||
| 218 | return target; | ||
| 219 | } | ||
| 220 | |||
| 221 | /** | ||
| 222 | * the local argument for this reference | ||
| 223 | */ | ||
| 224 | public final LocalMember getLocalArgument() { | ||
| 225 | return localArgument; | ||
| 226 | } | ||
| 227 | |||
| 228 | /** | ||
| 229 | * the field allocated in the client for this reference | ||
| 230 | */ | ||
| 231 | public final MemberDefinition getLocalField() { | ||
| 232 | return localField; | ||
| 233 | } | ||
| 234 | |||
| 235 | /** | ||
| 236 | * Get the local field, creating one if necessary. | ||
| 237 | * The client class must not be frozen. | ||
| 238 | */ | ||
| 239 | public final MemberDefinition getLocalField(Environment env) { | ||
| 240 | if (localField == null) { | ||
| 241 | makeLocalField(env); | ||
| 242 | } | ||
| 243 | return localField; | ||
| 244 | } | ||
| 245 | |||
| 246 | /** | ||
| 247 | * the client class | ||
| 248 | */ | ||
| 249 | public final ClassDefinition getClient() { | ||
| 250 | return client; | ||
| 251 | } | ||
| 252 | |||
| 253 | /** | ||
| 254 | * the next reference in the client's list | ||
| 255 | */ | ||
| 256 | public final UplevelReference getNext() { | ||
| 257 | return next; | ||
| 258 | } | ||
| 259 | |||
| 260 | /** | ||
| 261 | * Tell if this uplevel reference is the up-level "this" pointer | ||
| 262 | * of an inner class. Such references are treated differently | ||
| 263 | * than others, because they affect constructor calls across | ||
| 264 | * compilation units. | ||
| 265 | */ | ||
| 266 | public boolean isClientOuterField() { | ||
| 267 | MemberDefinition outerf = client.findOuterMember(); | ||
| 268 | return (outerf != null) && (localField == outerf); | ||
| 269 | } | ||
| 270 | |||
| 271 | /** | ||
| 272 | * Tell if my local argument is directly available in this context. | ||
| 273 | * If not, the uplevel reference will have to be via a class field. | ||
| 274 | * <p> | ||
| 275 | * This must be called in a context which is local | ||
| 276 | * to the client of the uplevel reference. | ||
| 277 | */ | ||
| 278 | public boolean localArgumentAvailable(Environment env, Context ctx) { | ||
| 279 | MemberDefinition reff = ctx.field; | ||
| 280 | if (reff.getClassDefinition() != client) { | ||
| 281 | throw new CompilerError("localArgumentAvailable"); | ||
| 282 | } | ||
| 283 | return ( reff.isConstructor() | ||
| 284 | || reff.isVariable() | ||
| 285 | || reff.isInitializer() ); | ||
| 286 | } | ||
| 287 | |||
| 288 | /** | ||
| 289 | * Process an uplevel reference. | ||
| 290 | * The only decision to make at this point is whether | ||
| 291 | * to build a "localField" instance variable, which | ||
| 292 | * is done (lazily) when localArgumentAvailable() proves false. | ||
| 293 | */ | ||
| 294 | public void noteReference(Environment env, Context ctx) { | ||
| 295 | if (localField == null && !localArgumentAvailable(env, ctx)) { | ||
| 296 | // We need an instance variable unless client is a constructor. | ||
| 297 | makeLocalField(env); | ||
| 298 | } | ||
| 299 | } | ||
| 300 | |||
| 301 | private void makeLocalField(Environment env) { | ||
| 302 | // Cannot alter decisions like this one at a late date. | ||
| 303 | client.referencesMustNotBeFrozen(); | ||
| 304 | int mod = M_PRIVATE | M_FINAL | M_SYNTHETIC; | ||
| 305 | localField = env.makeMemberDefinition(env, | ||
| 306 | localArgument.getWhere(), | ||
| 307 | client, null, | ||
| 308 | mod, | ||
| 309 | localArgument.getType(), | ||
| 310 | localArgument.getName(), | ||
| 311 | null, null, null); | ||
| 312 | } | ||
| 313 | |||
| 314 | /** | ||
| 315 | * Assuming noteReference() is all taken care of, | ||
| 316 | * build an uplevel reference. | ||
| 317 | * <p> | ||
| 318 | * This must be called in a context which is local | ||
| 319 | * to the client of the uplevel reference. | ||
| 320 | */ | ||
| 321 | public Expression makeLocalReference(Environment env, Context ctx) { | ||
| 322 | if (ctx.field.getClassDefinition() != client) { | ||
| 323 | throw new CompilerError("makeLocalReference"); | ||
| 324 | } | ||
| 325 | if (localArgumentAvailable(env, ctx)) { | ||
| 326 | return new IdentifierExpression(0, localArgument); | ||
| 327 | } else { | ||
| 328 | return makeFieldReference(env, ctx); | ||
| 329 | } | ||
| 330 | } | ||
| 331 | |||
| 332 | /** | ||
| 333 | * As with makeLocalReference(), build a locally-usable reference. | ||
| 334 | * Ignore the availability of local arguments; always use a class field. | ||
| 335 | */ | ||
| 336 | public Expression makeFieldReference(Environment env, Context ctx) { | ||
| 337 | Expression e = ctx.findOuterLink(env, 0, localField); | ||
| 338 | return new FieldExpression(0, e, localField); | ||
| 339 | } | ||
| 340 | |||
| 341 | /** | ||
| 342 | * During the inline phase, call this on a list of references | ||
| 343 | * for which the code phase will later emit arguments. | ||
| 344 | * It will make sure that any "double-uplevel" values | ||
| 345 | * needed by the callee are also present at the call site. | ||
| 346 | * <p> | ||
| 347 | * If any reference is a "ClientOuterField", it is skipped | ||
| 348 | * by this method (and by willCodeArguments). This is because | ||
| 349 | */ | ||
| 350 | public void willCodeArguments(Environment env, Context ctx) { | ||
| 351 | if (!isClientOuterField()) { | ||
| 352 | ctx.noteReference(env, target); | ||
| 353 | } | ||
| 354 | |||
| 355 | if (next != null) { | ||
| 356 | next.willCodeArguments(env, ctx); | ||
| 357 | } | ||
| 358 | } | ||
| 359 | |||
| 360 | /** | ||
| 361 | * Code is being generated for a call to a constructor of | ||
| 362 | * the client class. Push an argument for the constructor. | ||
| 363 | */ | ||
| 364 | public void codeArguments(Environment env, Context ctx, Assembler asm, | ||
| 365 | long where, MemberDefinition conField) { | ||
| 366 | if (!isClientOuterField()) { | ||
| 367 | Expression e = ctx.makeReference(env, target); | ||
| 368 | e.codeValue(env, ctx, asm); | ||
| 369 | } | ||
| 370 | |||
| 371 | if (next != null) { | ||
| 372 | next.codeArguments(env, ctx, asm, where, conField); | ||
| 373 | } | ||
| 374 | } | ||
| 375 | |||
| 376 | /** | ||
| 377 | * Code is being generated for a constructor of the client class. | ||
| 378 | * Emit code which initializes the instance. | ||
| 379 | */ | ||
| 380 | public void codeInitialization(Environment env, Context ctx, Assembler asm, | ||
| 381 | long where, MemberDefinition conField) { | ||
| 382 | // If the reference is a clientOuterField, then the initialization | ||
| 383 | // code is generated in MethodExpression.makeVarInits(). | ||
| 384 | // (Fix for bug 4075063.) | ||
| 385 | if (localField != null && !isClientOuterField()) { | ||
| 386 | Expression e = ctx.makeReference(env, target); | ||
| 387 | Expression f = makeFieldReference(env, ctx); | ||
| 388 | e = new AssignExpression(e.getWhere(), f, e); | ||
| 389 | e.type = localField.getType(); | ||
| 390 | e.code(env, ctx, asm); | ||
| 391 | } | ||
| 392 | |||
| 393 | if (next != null) { | ||
| 394 | next.codeInitialization(env, ctx, asm, where, conField); | ||
| 395 | } | ||
| 396 | } | ||
| 397 | |||
| 398 | public String toString() { | ||
| 399 | return "[" + localArgument + " in " + client + "]"; | ||
| 400 | } | ||
| 401 | } | ||