Mercurial > hg > truffle
annotate src/share/vm/ci/ciField.cpp @ 2177:3582bf76420e
6990754: Use native memory and reference counting to implement SymbolTable
Summary: move symbols from permgen into C heap and reference count them
Reviewed-by: never, acorn, jmasa, stefank
| author | coleenp |
|---|---|
| date | Thu, 27 Jan 2011 16:11:27 -0800 |
| parents | f95d63e2154a |
| children | d25d4ca69222 1957c1478794 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 1999, 2010, 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 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "ci/ciField.hpp" | |
| 27 #include "ci/ciInstanceKlass.hpp" | |
| 28 #include "ci/ciUtilities.hpp" | |
| 29 #include "classfile/systemDictionary.hpp" | |
| 30 #include "gc_interface/collectedHeap.inline.hpp" | |
| 31 #include "interpreter/linkResolver.hpp" | |
| 32 #include "memory/universe.inline.hpp" | |
| 33 #include "oops/oop.inline.hpp" | |
| 34 #include "oops/oop.inline2.hpp" | |
| 35 #include "runtime/fieldDescriptor.hpp" | |
| 0 | 36 |
| 37 // ciField | |
| 38 // | |
| 39 // This class represents the result of a field lookup in the VM. | |
| 40 // The lookup may not succeed, in which case the information in | |
| 41 // the ciField will be incomplete. | |
| 42 | |
| 43 // The ciObjectFactory cannot create circular data structures in one query. | |
| 44 // To avoid vicious circularities, we initialize ciField::_type to NULL | |
| 45 // for reference types and derive it lazily from the ciField::_signature. | |
| 46 // Primitive types are eagerly initialized, and basic layout queries | |
| 47 // can succeed without initialization, using only the BasicType of the field. | |
| 48 | |
| 49 // Notes on bootstrapping and shared CI objects: A field is shared if and | |
| 50 // only if it is (a) non-static and (b) declared by a shared instance klass. | |
| 51 // This allows non-static field lists to be cached on shared types. | |
| 52 // Because the _type field is lazily initialized, however, there is a | |
| 53 // special restriction that a shared field cannot cache an unshared type. | |
| 54 // This puts a small performance penalty on shared fields with unshared | |
| 55 // types, such as StackTraceElement[] Throwable.stackTrace. | |
| 56 // (Throwable is shared because ClassCastException is shared, but | |
| 57 // StackTraceElement is not presently shared.) | |
| 58 | |
| 59 // It is not a vicious circularity for a ciField to recursively create | |
| 60 // the ciSymbols necessary to represent its name and signature. | |
| 61 // Therefore, these items are created eagerly, and the name and signature | |
| 62 // of a shared field are themselves shared symbols. This somewhat | |
| 63 // pollutes the set of shared CI objects: It grows from 50 to 93 items, | |
| 64 // with all of the additional 43 being uninteresting shared ciSymbols. | |
| 65 // This adds at most one step to the binary search, an amount which | |
| 66 // decreases for complex compilation tasks. | |
| 67 | |
| 68 // ------------------------------------------------------------------ | |
| 69 // ciField::ciField | |
| 70 ciField::ciField(ciInstanceKlass* klass, int index): _known_to_link_with(NULL) { | |
| 71 ASSERT_IN_VM; | |
| 72 CompilerThread *thread = CompilerThread::current(); | |
| 73 | |
| 74 assert(ciObjectFactory::is_initialized(), "not a shared field"); | |
| 75 | |
| 76 assert(klass->get_instanceKlass()->is_linked(), "must be linked before using its constan-pool"); | |
| 77 | |
| 78 _cp_index = index; | |
| 79 constantPoolHandle cpool(thread, klass->get_instanceKlass()->constants()); | |
| 80 | |
| 81 // Get the field's name, signature, and type. | |
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82 Symbol* name = cpool->name_ref_at(index); |
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83 _name = ciEnv::current(thread)->get_symbol(name); |
| 0 | 84 |
| 85 int nt_index = cpool->name_and_type_ref_index_at(index); | |
| 86 int sig_index = cpool->signature_ref_index_at(nt_index); | |
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87 Symbol* signature = cpool->symbol_at(sig_index); |
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88 _signature = ciEnv::current(thread)->get_symbol(signature); |
| 0 | 89 |
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90 BasicType field_type = FieldType::basic_type(signature); |
| 0 | 91 |
| 92 // If the field is a pointer type, get the klass of the | |
| 93 // field. | |
| 94 if (field_type == T_OBJECT || field_type == T_ARRAY) { | |
| 95 bool ignore; | |
| 96 // This is not really a class reference; the index always refers to the | |
| 97 // field's type signature, as a symbol. Linkage checks do not apply. | |
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98 _type = ciEnv::current(thread)->get_klass_by_index(cpool, sig_index, ignore, klass); |
| 0 | 99 } else { |
| 100 _type = ciType::make(field_type); | |
| 101 } | |
| 102 | |
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103 _name = (ciSymbol*)ciEnv::current(thread)->get_symbol(name); |
| 0 | 104 |
| 105 // Get the field's declared holder. | |
| 106 // | |
| 107 // Note: we actually create a ciInstanceKlass for this klass, | |
| 108 // even though we may not need to. | |
| 109 int holder_index = cpool->klass_ref_index_at(index); | |
| 110 bool holder_is_accessible; | |
| 111 ciInstanceKlass* declared_holder = | |
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112 ciEnv::current(thread)->get_klass_by_index(cpool, holder_index, |
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113 holder_is_accessible, |
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114 klass)->as_instance_klass(); |
| 0 | 115 |
| 116 // The declared holder of this field may not have been loaded. | |
| 117 // Bail out with partial field information. | |
| 118 if (!holder_is_accessible) { | |
| 119 // _cp_index and _type have already been set. | |
| 120 // The default values for _flags and _constant_value will suffice. | |
| 121 // We need values for _holder, _offset, and _is_constant, | |
| 122 _holder = declared_holder; | |
| 123 _offset = -1; | |
| 124 _is_constant = false; | |
| 125 return; | |
| 126 } | |
| 127 | |
| 128 instanceKlass* loaded_decl_holder = declared_holder->get_instanceKlass(); | |
| 129 | |
| 130 // Perform the field lookup. | |
| 131 fieldDescriptor field_desc; | |
| 132 klassOop canonical_holder = | |
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133 loaded_decl_holder->find_field(name, signature, &field_desc); |
| 0 | 134 if (canonical_holder == NULL) { |
| 135 // Field lookup failed. Will be detected by will_link. | |
| 136 _holder = declared_holder; | |
| 137 _offset = -1; | |
| 138 _is_constant = false; | |
| 139 return; | |
| 140 } | |
| 141 | |
| 142 assert(canonical_holder == field_desc.field_holder(), "just checking"); | |
| 143 initialize_from(&field_desc); | |
| 144 } | |
| 145 | |
| 146 ciField::ciField(fieldDescriptor *fd): _known_to_link_with(NULL) { | |
| 147 ASSERT_IN_VM; | |
| 148 | |
| 149 _cp_index = -1; | |
| 150 | |
| 151 // Get the field's name, signature, and type. | |
| 152 ciEnv* env = CURRENT_ENV; | |
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153 _name = env->get_symbol(fd->name()); |
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154 _signature = env->get_symbol(fd->signature()); |
| 0 | 155 |
| 156 BasicType field_type = fd->field_type(); | |
| 157 | |
| 158 // If the field is a pointer type, get the klass of the | |
| 159 // field. | |
| 160 if (field_type == T_OBJECT || field_type == T_ARRAY) { | |
| 161 _type = NULL; // must call compute_type on first access | |
| 162 } else { | |
| 163 _type = ciType::make(field_type); | |
| 164 } | |
| 165 | |
| 166 initialize_from(fd); | |
| 167 | |
| 168 // Either (a) it is marked shared, or else (b) we are done bootstrapping. | |
| 169 assert(is_shared() || ciObjectFactory::is_initialized(), | |
| 170 "bootstrap classes must not create & cache unshared fields"); | |
| 171 } | |
| 172 | |
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173 static bool trust_final_non_static_fields(ciInstanceKlass* holder) { |
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174 if (holder == NULL) |
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175 return false; |
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176 if (holder->name() == ciSymbol::java_lang_System()) |
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177 // Never trust strangely unstable finals: System.out, etc. |
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178 return false; |
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179 // Even if general trusting is disabled, trust system-built closures in these packages. |
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180 if (holder->is_in_package("java/dyn") || holder->is_in_package("sun/dyn")) |
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181 return true; |
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182 return TrustFinalNonStaticFields; |
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183 } |
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184 |
| 0 | 185 void ciField::initialize_from(fieldDescriptor* fd) { |
| 186 // Get the flags, offset, and canonical holder of the field. | |
| 187 _flags = ciFlags(fd->access_flags()); | |
| 188 _offset = fd->offset(); | |
| 189 _holder = CURRENT_ENV->get_object(fd->field_holder())->as_instance_klass(); | |
| 190 | |
| 191 // Check to see if the field is constant. | |
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192 if (_holder->is_initialized() && this->is_final()) { |
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193 if (!this->is_static()) { |
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194 // A field can be constant if it's a final static field or if it's |
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195 // a final non-static field of a trusted class ({java,sun}.dyn). |
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196 if (trust_final_non_static_fields(_holder)) { |
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197 _is_constant = true; |
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198 return; |
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199 } |
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200 _is_constant = false; |
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201 return; |
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202 } |
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203 |
| 0 | 204 // This field just may be constant. The only cases where it will |
| 205 // not be constant are: | |
| 206 // | |
| 207 // 1. The field holds a non-perm-space oop. The field is, strictly | |
| 208 // speaking, constant but we cannot embed non-perm-space oops into | |
| 209 // generated code. For the time being we need to consider the | |
| 210 // field to be not constant. | |
| 211 // 2. The field is a *special* static&final field whose value | |
| 212 // may change. The three examples are java.lang.System.in, | |
| 213 // java.lang.System.out, and java.lang.System.err. | |
| 214 | |
| 215 klassOop k = _holder->get_klassOop(); | |
| 1142 | 216 assert( SystemDictionary::System_klass() != NULL, "Check once per vm"); |
| 217 if( k == SystemDictionary::System_klass() ) { | |
| 0 | 218 // Check offsets for case 2: System.in, System.out, or System.err |
| 219 if( _offset == java_lang_System::in_offset_in_bytes() || | |
| 220 _offset == java_lang_System::out_offset_in_bytes() || | |
| 221 _offset == java_lang_System::err_offset_in_bytes() ) { | |
| 222 _is_constant = false; | |
| 223 return; | |
| 224 } | |
| 225 } | |
| 226 | |
| 227 _is_constant = true; | |
| 228 switch(type()->basic_type()) { | |
| 229 case T_BYTE: | |
| 230 _constant_value = ciConstant(type()->basic_type(), k->byte_field(_offset)); | |
| 231 break; | |
| 232 case T_CHAR: | |
| 233 _constant_value = ciConstant(type()->basic_type(), k->char_field(_offset)); | |
| 234 break; | |
| 235 case T_SHORT: | |
| 236 _constant_value = ciConstant(type()->basic_type(), k->short_field(_offset)); | |
| 237 break; | |
| 238 case T_BOOLEAN: | |
| 239 _constant_value = ciConstant(type()->basic_type(), k->bool_field(_offset)); | |
| 240 break; | |
| 241 case T_INT: | |
| 242 _constant_value = ciConstant(type()->basic_type(), k->int_field(_offset)); | |
| 243 break; | |
| 244 case T_FLOAT: | |
| 245 _constant_value = ciConstant(k->float_field(_offset)); | |
| 246 break; | |
| 247 case T_DOUBLE: | |
| 248 _constant_value = ciConstant(k->double_field(_offset)); | |
| 249 break; | |
| 250 case T_LONG: | |
| 251 _constant_value = ciConstant(k->long_field(_offset)); | |
| 252 break; | |
| 253 case T_OBJECT: | |
| 254 case T_ARRAY: | |
| 255 { | |
| 256 oop o = k->obj_field(_offset); | |
| 257 | |
| 258 // A field will be "constant" if it is known always to be | |
| 259 // a non-null reference to an instance of a particular class, | |
| 260 // or to a particular array. This can happen even if the instance | |
| 261 // or array is not perm. In such a case, an "unloaded" ciArray | |
| 262 // or ciInstance is created. The compiler may be able to use | |
| 263 // information about the object's class (which is exact) or length. | |
| 264 | |
| 265 if (o == NULL) { | |
| 266 _constant_value = ciConstant(type()->basic_type(), ciNullObject::make()); | |
| 267 } else { | |
| 268 _constant_value = ciConstant(type()->basic_type(), CURRENT_ENV->get_object(o)); | |
| 269 assert(_constant_value.as_object() == CURRENT_ENV->get_object(o), "check interning"); | |
| 270 } | |
| 271 } | |
| 272 } | |
| 273 } else { | |
| 274 _is_constant = false; | |
| 275 } | |
| 276 } | |
| 277 | |
| 278 // ------------------------------------------------------------------ | |
| 279 // ciField::compute_type | |
| 280 // | |
| 281 // Lazily compute the type, if it is an instance klass. | |
| 282 ciType* ciField::compute_type() { | |
| 283 GUARDED_VM_ENTRY(return compute_type_impl();) | |
| 284 } | |
| 285 | |
| 286 ciType* ciField::compute_type_impl() { | |
| 287 ciKlass* type = CURRENT_ENV->get_klass_by_name_impl(_holder, _signature, false); | |
| 288 if (!type->is_primitive_type() && is_shared()) { | |
| 289 // We must not cache a pointer to an unshared type, in a shared field. | |
| 290 bool type_is_also_shared = false; | |
| 291 if (type->is_type_array_klass()) { | |
| 292 type_is_also_shared = true; // int[] etc. are explicitly bootstrapped | |
| 293 } else if (type->is_instance_klass()) { | |
| 294 type_is_also_shared = type->as_instance_klass()->is_shared(); | |
| 295 } else { | |
| 296 // Currently there is no 'shared' query for array types. | |
| 297 type_is_also_shared = !ciObjectFactory::is_initialized(); | |
| 298 } | |
| 299 if (!type_is_also_shared) | |
| 300 return type; // Bummer. | |
| 301 } | |
| 302 _type = type; | |
| 303 return type; | |
| 304 } | |
| 305 | |
| 306 | |
| 307 // ------------------------------------------------------------------ | |
| 308 // ciField::will_link | |
| 309 // | |
| 310 // Can a specific access to this field be made without causing | |
| 311 // link errors? | |
| 312 bool ciField::will_link(ciInstanceKlass* accessing_klass, | |
| 313 Bytecodes::Code bc) { | |
| 314 VM_ENTRY_MARK; | |
| 315 if (_offset == -1) { | |
| 316 // at creation we couldn't link to our holder so we need to | |
| 317 // maintain that stance, otherwise there's no safe way to use this | |
| 318 // ciField. | |
| 319 return false; | |
| 320 } | |
| 321 | |
| 322 if (_known_to_link_with == accessing_klass) { | |
| 323 return true; | |
| 324 } | |
| 325 | |
| 326 FieldAccessInfo result; | |
| 327 constantPoolHandle c_pool(THREAD, | |
| 328 accessing_klass->get_instanceKlass()->constants()); | |
| 329 LinkResolver::resolve_field(result, c_pool, _cp_index, | |
| 330 Bytecodes::java_code(bc), | |
| 331 true, false, KILL_COMPILE_ON_FATAL_(false)); | |
| 332 | |
| 333 // update the hit-cache, unless there is a problem with memory scoping: | |
| 334 if (accessing_klass->is_shared() || !is_shared()) | |
| 335 _known_to_link_with = accessing_klass; | |
| 336 | |
| 337 return true; | |
| 338 } | |
| 339 | |
| 340 // ------------------------------------------------------------------ | |
| 341 // ciField::print | |
| 342 void ciField::print() { | |
| 343 tty->print("<ciField "); | |
| 344 _holder->print_name(); | |
| 345 tty->print("."); | |
| 346 _name->print_symbol(); | |
| 347 tty->print(" offset=%d type=", _offset); | |
| 348 if (_type != NULL) _type->print_name(); | |
| 349 else tty->print("(reference)"); | |
| 350 tty->print(" is_constant=%s", bool_to_str(_is_constant)); | |
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351 if (_is_constant && is_static()) { |
| 0 | 352 tty->print(" constant_value="); |
| 353 _constant_value.print(); | |
| 354 } | |
| 355 tty->print(">"); | |
| 356 } | |
| 357 | |
| 358 // ------------------------------------------------------------------ | |
| 359 // ciField::print_name_on | |
| 360 // | |
| 361 // Print the name of this field | |
| 362 void ciField::print_name_on(outputStream* st) { | |
| 363 name()->print_symbol_on(st); | |
| 364 } |