ciField.cpp revision 3602:da91efe96a93
1227569Sphilip/* 2301388Sarybchik * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved. 3284555Sarybchik * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4227569Sphilip * 5227569Sphilip * This code is free software; you can redistribute it and/or modify it 6284555Sarybchik * under the terms of the GNU General Public License version 2 only, as 7227569Sphilip * published by the Free Software Foundation. 8284555Sarybchik * 9284555Sarybchik * This code is distributed in the hope that it will be useful, but WITHOUT 10284555Sarybchik * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11284555Sarybchik * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12284555Sarybchik * version 2 for more details (a copy is included in the LICENSE file that 13284555Sarybchik * accompanied this code). 14284555Sarybchik * 15284555Sarybchik * You should have received a copy of the GNU General Public License version 16284555Sarybchik * 2 along with this work; if not, write to the Free Software Foundation, 17284555Sarybchik * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18284555Sarybchik * 19284555Sarybchik * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20284555Sarybchik * or visit www.oracle.com if you need additional information or have any 21284555Sarybchik * questions. 22284555Sarybchik * 23284555Sarybchik */ 24284555Sarybchik 25284555Sarybchik#include "precompiled.hpp" 26284555Sarybchik#include "ci/ciField.hpp" 27284555Sarybchik#include "ci/ciInstanceKlass.hpp" 28284555Sarybchik#include "ci/ciUtilities.hpp" 29227569Sphilip#include "classfile/systemDictionary.hpp" 30228078Sphilip#include "gc_interface/collectedHeap.inline.hpp" 31228078Sphilip#include "interpreter/linkResolver.hpp" 32228078Sphilip#include "memory/universe.inline.hpp" 33228078Sphilip#include "oops/oop.inline.hpp" 34227569Sphilip#include "oops/oop.inline2.hpp" 35227569Sphilip#include "runtime/fieldDescriptor.hpp" 36284555Sarybchik 37227569Sphilip// ciField 38227569Sphilip// 39227569Sphilip// This class represents the result of a field lookup in the VM. 40311064Sarybchik// The lookup may not succeed, in which case the information in 41311064Sarybchik// the ciField will be incomplete. 42293927Sarybchik 43227569Sphilip// The ciObjectFactory cannot create circular data structures in one query. 44227569Sphilip// To avoid vicious circularities, we initialize ciField::_type to NULL 45227569Sphilip// for reference types and derive it lazily from the ciField::_signature. 46227569Sphilip// Primitive types are eagerly initialized, and basic layout queries 47227569Sphilip// can succeed without initialization, using only the BasicType of the field. 48342516Sarybchik 49342516Sarybchik// Notes on bootstrapping and shared CI objects: A field is shared if and 50293927Sarybchik// only if it is (a) non-static and (b) declared by a shared instance klass. 51227569Sphilip// This allows non-static field lists to be cached on shared types. 52227569Sphilip// Because the _type field is lazily initialized, however, there is a 53284555Sarybchik// special restriction that a shared field cannot cache an unshared type. 54284555Sarybchik// This puts a small performance penalty on shared fields with unshared 55284555Sarybchik// types, such as StackTraceElement[] Throwable.stackTrace. 56284555Sarybchik// (Throwable is shared because ClassCastException is shared, but 57227569Sphilip// StackTraceElement is not presently shared.) 58227569Sphilip 59227569Sphilip// It is not a vicious circularity for a ciField to recursively create 60227569Sphilip// the ciSymbols necessary to represent its name and signature. 61227569Sphilip// Therefore, these items are created eagerly, and the name and signature 62227569Sphilip// of a shared field are themselves shared symbols. This somewhat 63227569Sphilip// pollutes the set of shared CI objects: It grows from 50 to 93 items, 64227569Sphilip// with all of the additional 43 being uninteresting shared ciSymbols. 65227569Sphilip// This adds at most one step to the binary search, an amount which 66227569Sphilip// decreases for complex compilation tasks. 67227569Sphilip 68227569Sphilip// ------------------------------------------------------------------ 69227569Sphilip// ciField::ciField 70227569SphilipciField::ciField(ciInstanceKlass* klass, int index): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) { 71227569Sphilip ASSERT_IN_VM; 72227569Sphilip CompilerThread *thread = CompilerThread::current(); 73227569Sphilip 74227569Sphilip assert(ciObjectFactory::is_initialized(), "not a shared field"); 75227569Sphilip 76227569Sphilip assert(klass->get_instanceKlass()->is_linked(), "must be linked before using its constan-pool"); 77293927Sarybchik 78227569Sphilip _cp_index = index; 79227569Sphilip constantPoolHandle cpool(thread, klass->get_instanceKlass()->constants()); 80227569Sphilip 81227569Sphilip // Get the field's name, signature, and type. 82311064Sarybchik Symbol* name = cpool->name_ref_at(index); 83311064Sarybchik _name = ciEnv::current(thread)->get_symbol(name); 84293927Sarybchik 85227569Sphilip int nt_index = cpool->name_and_type_ref_index_at(index); 86227569Sphilip int sig_index = cpool->signature_ref_index_at(nt_index); 87227569Sphilip Symbol* signature = cpool->symbol_at(sig_index); 88227569Sphilip _signature = ciEnv::current(thread)->get_symbol(signature); 89284555Sarybchik 90284555Sarybchik BasicType field_type = FieldType::basic_type(signature); 91284555Sarybchik 92284555Sarybchik // If the field is a pointer type, get the klass of the 93293927Sarybchik // field. 94227569Sphilip if (field_type == T_OBJECT || field_type == T_ARRAY) { 95284555Sarybchik bool ignore; 96284555Sarybchik // This is not really a class reference; the index always refers to the 97284555Sarybchik // field's type signature, as a symbol. Linkage checks do not apply. 98227569Sphilip _type = ciEnv::current(thread)->get_klass_by_index(cpool, sig_index, ignore, klass); 99284555Sarybchik } else { 100284555Sarybchik _type = ciType::make(field_type); 101227569Sphilip } 102227569Sphilip 103280550Sarybchik _name = (ciSymbol*)ciEnv::current(thread)->get_symbol(name); 104227569Sphilip 105284555Sarybchik // Get the field's declared holder. 106227569Sphilip // 107311079Sarybchik // Note: we actually create a ciInstanceKlass for this klass, 108311079Sarybchik // even though we may not need to. 109311079Sarybchik int holder_index = cpool->klass_ref_index_at(index); 110311079Sarybchik bool holder_is_accessible; 111311079Sarybchik ciInstanceKlass* declared_holder = 112311079Sarybchik ciEnv::current(thread)->get_klass_by_index(cpool, holder_index, 113311079Sarybchik holder_is_accessible, 114280550Sarybchik klass)->as_instance_klass(); 115280550Sarybchik 116284555Sarybchik // The declared holder of this field may not have been loaded. 117280550Sarybchik // Bail out with partial field information. 118280550Sarybchik if (!holder_is_accessible) { 119284555Sarybchik // _cp_index and _type have already been set. 120284555Sarybchik // The default values for _flags and _constant_value will suffice. 121280550Sarybchik // We need values for _holder, _offset, and _is_constant, 122284555Sarybchik _holder = declared_holder; 123280550Sarybchik _offset = -1; 124280550Sarybchik _is_constant = false; 125280588Sarybchik return; 126280588Sarybchik } 127280588Sarybchik 128280588Sarybchik InstanceKlass* loaded_decl_holder = declared_holder->get_instanceKlass(); 129280550Sarybchik 130284555Sarybchik // Perform the field lookup. 131284555Sarybchik fieldDescriptor field_desc; 132227569Sphilip Klass* canonical_holder = 133284555Sarybchik loaded_decl_holder->find_field(name, signature, &field_desc); 134284555Sarybchik if (canonical_holder == NULL) { 135284555Sarybchik // Field lookup failed. Will be detected by will_link. 136227569Sphilip _holder = declared_holder; 137284555Sarybchik _offset = -1; 138284555Sarybchik _is_constant = false; 139227569Sphilip return; 140311768Sarybchik } 141311768Sarybchik 142311768Sarybchik assert(canonical_holder == field_desc.field_holder(), "just checking"); 143311768Sarybchik initialize_from(&field_desc); 144284555Sarybchik} 145284555Sarybchik 146284555SarybchikciField::ciField(fieldDescriptor *fd): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) { 147284555Sarybchik ASSERT_IN_VM; 148284555Sarybchik 149284555Sarybchik _cp_index = -1; 150284555Sarybchik 151284555Sarybchik // Get the field's name, signature, and type. 152284555Sarybchik ciEnv* env = CURRENT_ENV; 153227569Sphilip _name = env->get_symbol(fd->name()); 154284555Sarybchik _signature = env->get_symbol(fd->signature()); 155284555Sarybchik 156284555Sarybchik BasicType field_type = fd->field_type(); 157227569Sphilip 158342480Sarybchik // If the field is a pointer type, get the klass of the 159342480Sarybchik // field. 160227569Sphilip if (field_type == T_OBJECT || field_type == T_ARRAY) { 161280562Sarybchik _type = NULL; // must call compute_type on first access 162280562Sarybchik } else { 163227569Sphilip _type = ciType::make(field_type); 164284555Sarybchik } 165284555Sarybchik 166294381Sarybchik initialize_from(fd); 167311078Sarybchik 168293953Sarybchik // Either (a) it is marked shared, or else (b) we are done bootstrapping. 169284555Sarybchik assert(is_shared() || ciObjectFactory::is_initialized(), 170301365Sarybchik "bootstrap classes must not create & cache unshared fields"); 171301365Sarybchik} 172301365Sarybchik 173301365Sarybchikstatic bool trust_final_non_static_fields(ciInstanceKlass* holder) { 174311495Sarybchik if (holder == NULL) 175311495Sarybchik return false; 176227569Sphilip if (holder->name() == ciSymbol::java_lang_System()) 177227569Sphilip // Never trust strangely unstable finals: System.out, etc. 178227569Sphilip return false; 179227569Sphilip // Even if general trusting is disabled, trust system-built closures in these packages. 180227569Sphilip if (holder->is_in_package("java/lang/invoke") || holder->is_in_package("sun/invoke")) 181293927Sarybchik return true; 182227569Sphilip return TrustFinalNonStaticFields; 183227569Sphilip} 184227569Sphilip 185227569Sphilipvoid ciField::initialize_from(fieldDescriptor* fd) { 186293927Sarybchik // Get the flags, offset, and canonical holder of the field. 187227569Sphilip _flags = ciFlags(fd->access_flags()); 188227569Sphilip _offset = fd->offset(); 189227569Sphilip _holder = CURRENT_ENV->get_instance_klass(fd->field_holder()); 190342495Sarybchik 191227569Sphilip // Check to see if the field is constant. 192342495Sarybchik if (_holder->is_initialized() && this->is_final()) { 193293927Sarybchik if (!this->is_static()) { 194227569Sphilip // A field can be constant if it's a final static field or if 195284555Sarybchik // it's a final non-static field of a trusted class (classes in 196284555Sarybchik // java.lang.invoke and sun.invoke packages and subpackages). 197227569Sphilip if (trust_final_non_static_fields(_holder)) { 198227569Sphilip _is_constant = true; 199227569Sphilip return; 200227569Sphilip } 201284555Sarybchik _is_constant = false; 202227569Sphilip return; 203227569Sphilip } 204227569Sphilip 205227569Sphilip // This field just may be constant. The only cases where it will 206227569Sphilip // not be constant are: 207227569Sphilip // 208293927Sarybchik // 1. The field holds a non-perm-space oop. The field is, strictly 209227569Sphilip // speaking, constant but we cannot embed non-perm-space oops into 210227569Sphilip // generated code. For the time being we need to consider the 211227569Sphilip // field to be not constant. 212227569Sphilip // 2. The field is a *special* static&final field whose value 213342507Sarybchik // may change. The three examples are java.lang.System.in, 214342507Sarybchik // java.lang.System.out, and java.lang.System.err. 215342507Sarybchik 216342507Sarybchik KlassHandle k = _holder->get_Klass(); 217342507Sarybchik assert( SystemDictionary::System_klass() != NULL, "Check once per vm"); 218342507Sarybchik if( k() == SystemDictionary::System_klass() ) { 219342507Sarybchik // Check offsets for case 2: System.in, System.out, or System.err 220342507Sarybchik if( _offset == java_lang_System::in_offset_in_bytes() || 221342507Sarybchik _offset == java_lang_System::out_offset_in_bytes() || 222342507Sarybchik _offset == java_lang_System::err_offset_in_bytes() ) { 223342507Sarybchik _is_constant = false; 224342507Sarybchik return; 225342507Sarybchik } 226342507Sarybchik } 227342507Sarybchik 228342507Sarybchik Handle mirror = k->java_mirror(); 229342507Sarybchik 230342507Sarybchik _is_constant = true; 231342507Sarybchik switch(type()->basic_type()) { 232342507Sarybchik case T_BYTE: 233342507Sarybchik _constant_value = ciConstant(type()->basic_type(), mirror->byte_field(_offset)); 234342507Sarybchik break; 235342507Sarybchik case T_CHAR: 236342507Sarybchik _constant_value = ciConstant(type()->basic_type(), mirror->char_field(_offset)); 237342507Sarybchik break; 238342507Sarybchik case T_SHORT: 239342507Sarybchik _constant_value = ciConstant(type()->basic_type(), mirror->short_field(_offset)); 240342507Sarybchik break; 241342507Sarybchik case T_BOOLEAN: 242342507Sarybchik _constant_value = ciConstant(type()->basic_type(), mirror->bool_field(_offset)); 243342507Sarybchik break; 244342507Sarybchik case T_INT: 245342507Sarybchik _constant_value = ciConstant(type()->basic_type(), mirror->int_field(_offset)); 246342507Sarybchik break; 247342507Sarybchik case T_FLOAT: 248342507Sarybchik _constant_value = ciConstant(mirror->float_field(_offset)); 249342507Sarybchik break; 250342507Sarybchik case T_DOUBLE: 251342507Sarybchik _constant_value = ciConstant(mirror->double_field(_offset)); 252342507Sarybchik break; 253342507Sarybchik case T_LONG: 254342507Sarybchik _constant_value = ciConstant(mirror->long_field(_offset)); 255342507Sarybchik break; 256342507Sarybchik case T_OBJECT: 257342507Sarybchik case T_ARRAY: 258342507Sarybchik { 259342507Sarybchik oop o = mirror->obj_field(_offset); 260342507Sarybchik 261342507Sarybchik // A field will be "constant" if it is known always to be 262342507Sarybchik // a non-null reference to an instance of a particular class, 263342507Sarybchik // or to a particular array. This can happen even if the instance 264342507Sarybchik // or array is not perm. In such a case, an "unloaded" ciArray 265342507Sarybchik // or ciInstance is created. The compiler may be able to use 266342507Sarybchik // information about the object's class (which is exact) or length. 267342507Sarybchik 268342507Sarybchik if (o == NULL) { 269342507Sarybchik _constant_value = ciConstant(type()->basic_type(), ciNullObject::make()); 270342507Sarybchik } else { 271342507Sarybchik _constant_value = ciConstant(type()->basic_type(), CURRENT_ENV->get_object(o)); 272342507Sarybchik assert(_constant_value.as_object() == CURRENT_ENV->get_object(o), "check interning"); 273342507Sarybchik } 274342507Sarybchik } 275342507Sarybchik } 276342507Sarybchik } else { 277342507Sarybchik _is_constant = false; 278342507Sarybchik } 279342507Sarybchik} 280342507Sarybchik 281342507Sarybchik// ------------------------------------------------------------------ 282342507Sarybchik// ciField::compute_type 283342507Sarybchik// 284293927Sarybchik// Lazily compute the type, if it is an instance klass. 285227569SphilipciType* ciField::compute_type() { 286227569Sphilip GUARDED_VM_ENTRY(return compute_type_impl();) 287227569Sphilip} 288227569Sphilip 289227569SphilipciType* ciField::compute_type_impl() { 290227569Sphilip ciKlass* type = CURRENT_ENV->get_klass_by_name_impl(_holder, constantPoolHandle(), _signature, false); 291227569Sphilip if (!type->is_primitive_type() && is_shared()) { 292284555Sarybchik // We must not cache a pointer to an unshared type, in a shared field. 293293927Sarybchik bool type_is_also_shared = false; 294227569Sphilip if (type->is_type_array_klass()) { 295227569Sphilip type_is_also_shared = true; // int[] etc. are explicitly bootstrapped 296227569Sphilip } else if (type->is_instance_klass()) { 297284555Sarybchik type_is_also_shared = type->as_instance_klass()->is_shared(); 298342507Sarybchik } else { 299227569Sphilip // Currently there is no 'shared' query for array types. 300227569Sphilip type_is_also_shared = !ciObjectFactory::is_initialized(); 301284555Sarybchik } 302284555Sarybchik if (!type_is_also_shared) 303284555Sarybchik return type; // Bummer. 304284555Sarybchik } 305284555Sarybchik _type = type; 306284555Sarybchik return type; 307284555Sarybchik} 308284555Sarybchik 309284555Sarybchik 310284555Sarybchik// ------------------------------------------------------------------ 311227569Sphilip// ciField::will_link 312227569Sphilip// 313284555Sarybchik// Can a specific access to this field be made without causing 314284555Sarybchik// link errors? 315227569Sphilipbool ciField::will_link(ciInstanceKlass* accessing_klass, 316227569Sphilip Bytecodes::Code bc) { 317284555Sarybchik VM_ENTRY_MARK; 318284555Sarybchik assert(bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic || 319227569Sphilip bc == Bytecodes::_getfield || bc == Bytecodes::_putfield, 320227569Sphilip "unexpected bytecode"); 321284555Sarybchik 322227569Sphilip if (_offset == -1) { 323227569Sphilip // at creation we couldn't link to our holder so we need to 324284555Sarybchik // maintain that stance, otherwise there's no safe way to use this 325284555Sarybchik // ciField. 326284555Sarybchik return false; 327227569Sphilip } 328227569Sphilip 329284555Sarybchik // Check for static/nonstatic mismatch 330227569Sphilip bool is_static = (bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic); 331284555Sarybchik if (is_static != this->is_static()) { 332227569Sphilip return false; 333227569Sphilip } 334227569Sphilip 335227569Sphilip // Get and put can have different accessibility rules 336227569Sphilip bool is_put = (bc == Bytecodes::_putfield || bc == Bytecodes::_putstatic); 337284555Sarybchik if (is_put) { 338227569Sphilip if (_known_to_link_with_put == accessing_klass) { 339227569Sphilip return true; 340227569Sphilip } 341227569Sphilip } else { 342227569Sphilip if (_known_to_link_with_get == accessing_klass) { 343284555Sarybchik return true; 344284555Sarybchik } 345227569Sphilip } 346227569Sphilip 347227569Sphilip FieldAccessInfo result; 348284555Sarybchik constantPoolHandle c_pool(THREAD, 349284555Sarybchik accessing_klass->get_instanceKlass()->constants()); 350227569Sphilip LinkResolver::resolve_field(result, c_pool, _cp_index, 351227569Sphilip Bytecodes::java_code(bc), 352227569Sphilip true, false, KILL_COMPILE_ON_FATAL_(false)); 353284555Sarybchik 354284555Sarybchik // update the hit-cache, unless there is a problem with memory scoping: 355227569Sphilip if (accessing_klass->is_shared() || !is_shared()) { 356227569Sphilip if (is_put) { 357227569Sphilip _known_to_link_with_put = accessing_klass; 358227569Sphilip } else { 359227569Sphilip _known_to_link_with_get = accessing_klass; 360227569Sphilip } 361227569Sphilip } 362284555Sarybchik 363284555Sarybchik return true; 364284555Sarybchik} 365284555Sarybchik 366227569Sphilip// ------------------------------------------------------------------ 367227569Sphilip// ciField::print 368227569Sphilipvoid ciField::print() { 369284555Sarybchik tty->print("<ciField "); 370227569Sphilip _holder->print_name(); 371227569Sphilip tty->print("."); 372227569Sphilip _name->print_symbol(); 373284555Sarybchik tty->print(" offset=%d type=", _offset); 374227569Sphilip if (_type != NULL) _type->print_name(); 375227569Sphilip else tty->print("(reference)"); 376227569Sphilip tty->print(" is_constant=%s", bool_to_str(_is_constant)); 377227569Sphilip if (_is_constant && is_static()) { 378227569Sphilip tty->print(" constant_value="); 379227569Sphilip _constant_value.print(); 380227569Sphilip } 381227569Sphilip tty->print(">"); 382227569Sphilip} 383227569Sphilip 384227569Sphilip// ------------------------------------------------------------------ 385227569Sphilip// ciField::print_name_on 386227569Sphilip// 387227569Sphilip// Print the name of this field 388227569Sphilipvoid ciField::print_name_on(outputStream* st) { 389227569Sphilip name()->print_symbol_on(st); 390227569Sphilip} 391227569Sphilip