Mercurial > hg > truffle
annotate src/share/vm/ci/ciField.cpp @ 1930:2d26b0046e0d
Merge.
| author | Thomas Wuerthinger <wuerthinger@ssw.jku.at> |
|---|---|
| date | Tue, 30 Nov 2010 14:53:30 +0100 |
| parents | 944071972cd9 e5dfb3ccb88b |
| children | 06f017f7daa7 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1999, 2009, Oracle and/or its affiliates. All rights reserved. |
| 0 | 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. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 #include "incls/_precompiled.incl" | |
| 26 #include "incls/_ciField.cpp.incl" | |
| 27 | |
| 28 // ciField | |
| 29 // | |
| 30 // This class represents the result of a field lookup in the VM. | |
| 31 // The lookup may not succeed, in which case the information in | |
| 32 // the ciField will be incomplete. | |
| 33 | |
| 34 // The ciObjectFactory cannot create circular data structures in one query. | |
| 35 // To avoid vicious circularities, we initialize ciField::_type to NULL | |
| 36 // for reference types and derive it lazily from the ciField::_signature. | |
| 37 // Primitive types are eagerly initialized, and basic layout queries | |
| 38 // can succeed without initialization, using only the BasicType of the field. | |
| 39 | |
| 40 // Notes on bootstrapping and shared CI objects: A field is shared if and | |
| 41 // only if it is (a) non-static and (b) declared by a shared instance klass. | |
| 42 // This allows non-static field lists to be cached on shared types. | |
| 43 // Because the _type field is lazily initialized, however, there is a | |
| 44 // special restriction that a shared field cannot cache an unshared type. | |
| 45 // This puts a small performance penalty on shared fields with unshared | |
| 46 // types, such as StackTraceElement[] Throwable.stackTrace. | |
| 47 // (Throwable is shared because ClassCastException is shared, but | |
| 48 // StackTraceElement is not presently shared.) | |
| 49 | |
| 50 // It is not a vicious circularity for a ciField to recursively create | |
| 51 // the ciSymbols necessary to represent its name and signature. | |
| 52 // Therefore, these items are created eagerly, and the name and signature | |
| 53 // of a shared field are themselves shared symbols. This somewhat | |
| 54 // pollutes the set of shared CI objects: It grows from 50 to 93 items, | |
| 55 // with all of the additional 43 being uninteresting shared ciSymbols. | |
| 56 // This adds at most one step to the binary search, an amount which | |
| 57 // decreases for complex compilation tasks. | |
| 58 | |
| 59 // ------------------------------------------------------------------ | |
| 60 // ciField::ciField | |
| 61 ciField::ciField(ciInstanceKlass* klass, int index): _known_to_link_with(NULL) { | |
| 62 ASSERT_IN_VM; | |
| 63 CompilerThread *thread = CompilerThread::current(); | |
| 64 | |
| 65 assert(ciObjectFactory::is_initialized(), "not a shared field"); | |
| 66 | |
| 67 assert(klass->get_instanceKlass()->is_linked(), "must be linked before using its constan-pool"); | |
| 68 | |
| 69 _cp_index = index; | |
| 70 constantPoolHandle cpool(thread, klass->get_instanceKlass()->constants()); | |
| 71 | |
| 72 // Get the field's name, signature, and type. | |
| 73 symbolHandle name (thread, cpool->name_ref_at(index)); | |
| 74 _name = ciEnv::current(thread)->get_object(name())->as_symbol(); | |
| 75 | |
| 76 int nt_index = cpool->name_and_type_ref_index_at(index); | |
| 77 int sig_index = cpool->signature_ref_index_at(nt_index); | |
| 78 symbolHandle signature (thread, cpool->symbol_at(sig_index)); | |
| 79 _signature = ciEnv::current(thread)->get_object(signature())->as_symbol(); | |
| 80 | |
| 81 BasicType field_type = FieldType::basic_type(signature()); | |
| 82 | |
| 83 // If the field is a pointer type, get the klass of the | |
| 84 // field. | |
| 85 if (field_type == T_OBJECT || field_type == T_ARRAY) { | |
| 86 bool ignore; | |
| 87 // This is not really a class reference; the index always refers to the | |
| 88 // field's type signature, as a symbol. Linkage checks do not apply. | |
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89 _type = ciEnv::current(thread)->get_klass_by_index(cpool, sig_index, ignore, klass); |
| 0 | 90 } else { |
| 91 _type = ciType::make(field_type); | |
| 92 } | |
| 93 | |
| 94 _name = (ciSymbol*)ciEnv::current(thread)->get_object(name()); | |
| 95 | |
| 96 // Get the field's declared holder. | |
| 97 // | |
| 98 // Note: we actually create a ciInstanceKlass for this klass, | |
| 99 // even though we may not need to. | |
| 100 int holder_index = cpool->klass_ref_index_at(index); | |
| 101 bool holder_is_accessible; | |
| 102 ciInstanceKlass* declared_holder = | |
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103 ciEnv::current(thread)->get_klass_by_index(cpool, holder_index, |
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104 holder_is_accessible, |
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105 klass)->as_instance_klass(); |
| 0 | 106 |
| 107 // The declared holder of this field may not have been loaded. | |
| 108 // Bail out with partial field information. | |
| 109 if (!holder_is_accessible) { | |
| 110 // _cp_index and _type have already been set. | |
| 111 // The default values for _flags and _constant_value will suffice. | |
| 112 // We need values for _holder, _offset, and _is_constant, | |
| 113 _holder = declared_holder; | |
| 114 _offset = -1; | |
| 115 _is_constant = false; | |
| 116 return; | |
| 117 } | |
| 118 | |
| 119 instanceKlass* loaded_decl_holder = declared_holder->get_instanceKlass(); | |
| 120 | |
| 121 // Perform the field lookup. | |
| 122 fieldDescriptor field_desc; | |
| 123 klassOop canonical_holder = | |
| 124 loaded_decl_holder->find_field(name(), signature(), &field_desc); | |
| 125 if (canonical_holder == NULL) { | |
| 126 // Field lookup failed. Will be detected by will_link. | |
| 127 _holder = declared_holder; | |
| 128 _offset = -1; | |
| 129 _is_constant = false; | |
| 130 return; | |
| 131 } | |
| 132 | |
| 133 assert(canonical_holder == field_desc.field_holder(), "just checking"); | |
| 134 initialize_from(&field_desc); | |
| 135 } | |
| 136 | |
| 137 ciField::ciField(fieldDescriptor *fd): _known_to_link_with(NULL) { | |
| 138 ASSERT_IN_VM; | |
| 139 | |
| 140 _cp_index = -1; | |
| 141 | |
| 142 // Get the field's name, signature, and type. | |
| 143 ciEnv* env = CURRENT_ENV; | |
| 144 _name = env->get_object(fd->name())->as_symbol(); | |
| 145 _signature = env->get_object(fd->signature())->as_symbol(); | |
| 146 | |
| 147 BasicType field_type = fd->field_type(); | |
| 148 | |
| 149 // If the field is a pointer type, get the klass of the | |
| 150 // field. | |
| 151 if (field_type == T_OBJECT || field_type == T_ARRAY) { | |
| 152 _type = NULL; // must call compute_type on first access | |
| 153 } else { | |
| 154 _type = ciType::make(field_type); | |
| 155 } | |
| 156 | |
| 157 initialize_from(fd); | |
| 158 | |
| 159 // Either (a) it is marked shared, or else (b) we are done bootstrapping. | |
| 160 assert(is_shared() || ciObjectFactory::is_initialized(), | |
| 161 "bootstrap classes must not create & cache unshared fields"); | |
| 162 } | |
| 163 | |
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164 static bool trust_final_non_static_fields(ciInstanceKlass* holder) { |
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165 if (holder == NULL) |
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166 return false; |
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167 if (holder->name() == ciSymbol::java_lang_System()) |
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168 // Never trust strangely unstable finals: System.out, etc. |
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169 return false; |
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170 // Even if general trusting is disabled, trust system-built closures in these packages. |
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171 if (holder->is_in_package("java/dyn") || holder->is_in_package("sun/dyn")) |
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172 return true; |
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173 return TrustFinalNonStaticFields; |
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174 } |
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175 |
| 0 | 176 void ciField::initialize_from(fieldDescriptor* fd) { |
| 177 // Get the flags, offset, and canonical holder of the field. | |
| 178 _flags = ciFlags(fd->access_flags()); | |
| 179 _offset = fd->offset(); | |
| 180 _holder = CURRENT_ENV->get_object(fd->field_holder())->as_instance_klass(); | |
| 181 | |
| 182 // Check to see if the field is constant. | |
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183 if (_holder->is_initialized() && this->is_final()) { |
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184 if (!this->is_static()) { |
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185 // A field can be constant if it's a final static field or if it's |
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186 // a final non-static field of a trusted class ({java,sun}.dyn). |
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187 if (trust_final_non_static_fields(_holder)) { |
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188 _is_constant = true; |
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189 return; |
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190 } |
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191 _is_constant = false; |
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192 return; |
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193 } |
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194 |
| 0 | 195 // This field just may be constant. The only cases where it will |
| 196 // not be constant are: | |
| 197 // | |
| 198 // 1. The field holds a non-perm-space oop. The field is, strictly | |
| 199 // speaking, constant but we cannot embed non-perm-space oops into | |
| 200 // generated code. For the time being we need to consider the | |
| 201 // field to be not constant. | |
| 202 // 2. The field is a *special* static&final field whose value | |
| 203 // may change. The three examples are java.lang.System.in, | |
| 204 // java.lang.System.out, and java.lang.System.err. | |
| 205 | |
| 206 klassOop k = _holder->get_klassOop(); | |
| 1142 | 207 assert( SystemDictionary::System_klass() != NULL, "Check once per vm"); |
| 208 if( k == SystemDictionary::System_klass() ) { | |
| 0 | 209 // Check offsets for case 2: System.in, System.out, or System.err |
| 210 if( _offset == java_lang_System::in_offset_in_bytes() || | |
| 211 _offset == java_lang_System::out_offset_in_bytes() || | |
| 212 _offset == java_lang_System::err_offset_in_bytes() ) { | |
| 213 _is_constant = false; | |
| 214 return; | |
| 215 } | |
| 216 } | |
| 217 | |
| 218 _is_constant = true; | |
| 219 switch(type()->basic_type()) { | |
| 220 case T_BYTE: | |
| 221 _constant_value = ciConstant(type()->basic_type(), k->byte_field(_offset)); | |
| 222 break; | |
| 223 case T_CHAR: | |
| 224 _constant_value = ciConstant(type()->basic_type(), k->char_field(_offset)); | |
| 225 break; | |
| 226 case T_SHORT: | |
| 227 _constant_value = ciConstant(type()->basic_type(), k->short_field(_offset)); | |
| 228 break; | |
| 229 case T_BOOLEAN: | |
| 230 _constant_value = ciConstant(type()->basic_type(), k->bool_field(_offset)); | |
| 231 break; | |
| 232 case T_INT: | |
| 233 _constant_value = ciConstant(type()->basic_type(), k->int_field(_offset)); | |
| 234 break; | |
| 235 case T_FLOAT: | |
| 236 _constant_value = ciConstant(k->float_field(_offset)); | |
| 237 break; | |
| 238 case T_DOUBLE: | |
| 239 _constant_value = ciConstant(k->double_field(_offset)); | |
| 240 break; | |
| 241 case T_LONG: | |
| 242 _constant_value = ciConstant(k->long_field(_offset)); | |
| 243 break; | |
| 244 case T_OBJECT: | |
| 245 case T_ARRAY: | |
| 246 { | |
| 247 oop o = k->obj_field(_offset); | |
| 248 | |
| 249 // A field will be "constant" if it is known always to be | |
| 250 // a non-null reference to an instance of a particular class, | |
| 251 // or to a particular array. This can happen even if the instance | |
| 252 // or array is not perm. In such a case, an "unloaded" ciArray | |
| 253 // or ciInstance is created. The compiler may be able to use | |
| 254 // information about the object's class (which is exact) or length. | |
| 255 | |
| 256 if (o == NULL) { | |
| 257 _constant_value = ciConstant(type()->basic_type(), ciNullObject::make()); | |
| 258 } else { | |
| 259 _constant_value = ciConstant(type()->basic_type(), CURRENT_ENV->get_object(o)); | |
| 260 assert(_constant_value.as_object() == CURRENT_ENV->get_object(o), "check interning"); | |
| 261 } | |
| 262 } | |
| 263 } | |
| 264 } else { | |
| 265 _is_constant = false; | |
| 266 } | |
| 267 } | |
| 268 | |
| 269 // ------------------------------------------------------------------ | |
| 270 // ciField::compute_type | |
| 271 // | |
| 272 // Lazily compute the type, if it is an instance klass. | |
| 273 ciType* ciField::compute_type() { | |
| 274 GUARDED_VM_ENTRY(return compute_type_impl();) | |
| 275 } | |
| 276 | |
| 277 ciType* ciField::compute_type_impl() { | |
| 278 ciKlass* type = CURRENT_ENV->get_klass_by_name_impl(_holder, _signature, false); | |
| 279 if (!type->is_primitive_type() && is_shared()) { | |
| 280 // We must not cache a pointer to an unshared type, in a shared field. | |
| 281 bool type_is_also_shared = false; | |
| 282 if (type->is_type_array_klass()) { | |
| 283 type_is_also_shared = true; // int[] etc. are explicitly bootstrapped | |
| 284 } else if (type->is_instance_klass()) { | |
| 285 type_is_also_shared = type->as_instance_klass()->is_shared(); | |
| 286 } else { | |
| 287 // Currently there is no 'shared' query for array types. | |
| 288 type_is_also_shared = !ciObjectFactory::is_initialized(); | |
| 289 } | |
| 290 if (!type_is_also_shared) | |
| 291 return type; // Bummer. | |
| 292 } | |
| 293 _type = type; | |
| 294 return type; | |
| 295 } | |
| 296 | |
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297 bool ciField::will_link(ciInstanceKlass* accessing_klass, |
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298 Bytecodes::Code bc) { |
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299 VM_ENTRY_MARK; |
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300 will_link_from_vm(accessing_klass, bc); |
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301 } |
| 0 | 302 |
| 303 // ------------------------------------------------------------------ | |
| 304 // ciField::will_link | |
| 305 // | |
| 306 // Can a specific access to this field be made without causing | |
| 307 // link errors? | |
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308 bool ciField::will_link_from_vm(ciInstanceKlass* accessing_klass, |
| 0 | 309 Bytecodes::Code bc) { |
| 1461 | 310 Thread* THREAD = Thread::current(); |
| 0 | 311 if (_offset == -1) { |
| 312 // at creation we couldn't link to our holder so we need to | |
| 313 // maintain that stance, otherwise there's no safe way to use this | |
| 314 // ciField. | |
| 315 return false; | |
| 316 } | |
| 317 | |
| 318 if (_known_to_link_with == accessing_klass) { | |
| 319 return true; | |
| 320 } | |
| 321 | |
| 322 FieldAccessInfo result; | |
| 323 constantPoolHandle c_pool(THREAD, | |
| 324 accessing_klass->get_instanceKlass()->constants()); | |
| 325 LinkResolver::resolve_field(result, c_pool, _cp_index, | |
| 326 Bytecodes::java_code(bc), | |
| 327 true, false, KILL_COMPILE_ON_FATAL_(false)); | |
| 328 | |
| 329 // update the hit-cache, unless there is a problem with memory scoping: | |
| 330 if (accessing_klass->is_shared() || !is_shared()) | |
| 331 _known_to_link_with = accessing_klass; | |
| 332 | |
| 333 return true; | |
| 334 } | |
| 335 | |
| 336 // ------------------------------------------------------------------ | |
| 337 // ciField::print | |
| 338 void ciField::print() { | |
| 339 tty->print("<ciField "); | |
| 340 _holder->print_name(); | |
| 341 tty->print("."); | |
| 342 _name->print_symbol(); | |
| 343 tty->print(" offset=%d type=", _offset); | |
| 344 if (_type != NULL) _type->print_name(); | |
| 345 else tty->print("(reference)"); | |
| 346 tty->print(" is_constant=%s", bool_to_str(_is_constant)); | |
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347 if (_is_constant && is_static()) { |
| 0 | 348 tty->print(" constant_value="); |
| 349 _constant_value.print(); | |
| 350 } | |
| 351 tty->print(">"); | |
| 352 } | |
| 353 | |
| 354 // ------------------------------------------------------------------ | |
| 355 // ciField::print_name_on | |
| 356 // | |
| 357 // Print the name of this field | |
| 358 void ciField::print_name_on(outputStream* st) { | |
| 359 name()->print_symbol_on(st); | |
| 360 } |