jdk8-mips64-public/hotspot: src/share/vm/ci/ciField.cpp@eef07cd490d4 (annotated)

src/share/vm/ci/ciField.cpp@eef07cd490d4 (annotated)

src/share/vm/ci/ciField.cpp

Wed, 03 Jul 2019 20:42:37 +0800

author: aoqi
date: Wed, 03 Jul 2019 20:42:37 +0800
changeset 9637: eef07cd490d4
parent 8856: ac27a9c85bea
permissions: -rw-r--r--

Merge

 /*
  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "ci/ciField.hpp"
 #include "ci/ciInstanceKlass.hpp"
 #include "ci/ciUtilities.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "gc_interface/collectedHeap.inline.hpp"
 #include "interpreter/linkResolver.hpp"
 #include "memory/universe.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "oops/oop.inline2.hpp"
 #include "runtime/fieldDescriptor.hpp"
 // ciField
 //
 // This class represents the result of a field lookup in the VM.
 // The lookup may not succeed, in which case the information in
 // the ciField will be incomplete.
 // The ciObjectFactory cannot create circular data structures in one query.
 // To avoid vicious circularities, we initialize ciField::_type to NULL
 // for reference types and derive it lazily from the ciField::_signature.
 // Primitive types are eagerly initialized, and basic layout queries
 // can succeed without initialization, using only the BasicType of the field.
 // Notes on bootstrapping and shared CI objects:  A field is shared if and
 // only if it is (a) non-static and (b) declared by a shared instance klass.
 // This allows non-static field lists to be cached on shared types.
 // Because the _type field is lazily initialized, however, there is a
 // special restriction that a shared field cannot cache an unshared type.
 // This puts a small performance penalty on shared fields with unshared
 // types, such as StackTraceElement[] Throwable.stackTrace.
 // (Throwable is shared because ClassCastException is shared, but
 // StackTraceElement is not presently shared.)
 // It is not a vicious circularity for a ciField to recursively create
 // the ciSymbols necessary to represent its name and signature.
 // Therefore, these items are created eagerly, and the name and signature
 // of a shared field are themselves shared symbols.  This somewhat
 // pollutes the set of shared CI objects:  It grows from 50 to 93 items,
 // with all of the additional 43 being uninteresting shared ciSymbols.
 // This adds at most one step to the binary search, an amount which
 // decreases for complex compilation tasks.
 // ------------------------------------------------------------------
 // ciField::ciField
 ciField::ciField(ciInstanceKlass* klass, int index): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) {
   ASSERT_IN_VM;
   CompilerThread *thread = CompilerThread::current();
   assert(ciObjectFactory::is_initialized(), "not a shared field");
   assert(klass->get_instanceKlass()->is_linked(), "must be linked before using its constan-pool");
   constantPoolHandle cpool(thread, klass->get_instanceKlass()->constants());
   // Get the field's name, signature, and type.
   Symbol* name  = cpool->name_ref_at(index);
   _name = ciEnv::current(thread)->get_symbol(name);
   int nt_index = cpool->name_and_type_ref_index_at(index);
   int sig_index = cpool->signature_ref_index_at(nt_index);
   Symbol* signature = cpool->symbol_at(sig_index);
   _signature = ciEnv::current(thread)->get_symbol(signature);
   BasicType field_type = FieldType::basic_type(signature);
   // If the field is a pointer type, get the klass of the
   // field.
   if (field_type == T_OBJECT || field_type == T_ARRAY) {
     bool ignore;
     // This is not really a class reference; the index always refers to the
     // field's type signature, as a symbol.  Linkage checks do not apply.
     _type = ciEnv::current(thread)->get_klass_by_index(cpool, sig_index, ignore, klass);
   } else {
     _type = ciType::make(field_type);
   }
   _name = (ciSymbol*)ciEnv::current(thread)->get_symbol(name);
   // Get the field's declared holder.
   //
   // Note: we actually create a ciInstanceKlass for this klass,
   // even though we may not need to.
   int holder_index = cpool->klass_ref_index_at(index);
   bool holder_is_accessible;
   ciInstanceKlass* declared_holder =
     ciEnv::current(thread)->get_klass_by_index(cpool, holder_index,
                                                holder_is_accessible,
                                                klass)->as_instance_klass();
   // The declared holder of this field may not have been loaded.
   // Bail out with partial field information.
   if (!holder_is_accessible) {
     // _type has already been set.
     // The default values for _flags and _constant_value will suffice.
     // We need values for _holder, _offset,  and _is_constant,
     _holder = declared_holder;
     _offset = -1;
     _is_constant = false;
     return;
   }
   InstanceKlass* loaded_decl_holder = declared_holder->get_instanceKlass();
   // Perform the field lookup.
   fieldDescriptor field_desc;
   Klass* canonical_holder =
     loaded_decl_holder->find_field(name, signature, &field_desc);
   if (canonical_holder == NULL) {
     // Field lookup failed.  Will be detected by will_link.
     _holder = declared_holder;
     _offset = -1;
     _is_constant = false;
     return;
   }
   // Access check based on declared_holder. canonical_holder should not be used
   // to check access because it can erroneously succeed. If this check fails,
   // propagate the declared holder to will_link() which in turn will bail out
   // compilation for this field access.
   if (!Reflection::verify_field_access(klass->get_Klass(), declared_holder->get_Klass(), canonical_holder, field_desc.access_flags(), true)) {
     _holder = declared_holder;
     _offset = -1;
     _is_constant = false;
     return;
   }
   assert(canonical_holder == field_desc.field_holder(), "just checking");
   initialize_from(&field_desc);
 }
 ciField::ciField(fieldDescriptor *fd): _known_to_link_with_put(NULL), _known_to_link_with_get(NULL) {
   ASSERT_IN_VM;
   // Get the field's name, signature, and type.
   ciEnv* env = CURRENT_ENV;
   _name = env->get_symbol(fd->name());
   _signature = env->get_symbol(fd->signature());
   BasicType field_type = fd->field_type();
   // If the field is a pointer type, get the klass of the
   // field.
   if (field_type == T_OBJECT || field_type == T_ARRAY) {
     _type = NULL;  // must call compute_type on first access
   } else {
     _type = ciType::make(field_type);
   }
   initialize_from(fd);
   // Either (a) it is marked shared, or else (b) we are done bootstrapping.
   assert(is_shared() || ciObjectFactory::is_initialized(),
          "bootstrap classes must not create & cache unshared fields");
 }
 static bool trust_final_non_static_fields(ciInstanceKlass* holder) {
   if (holder == NULL)
     return false;
   if (holder->name() == ciSymbol::java_lang_System())
     // Never trust strangely unstable finals:  System.out, etc.
     return false;
   // Even if general trusting is disabled, trust system-built closures in these packages.
   if (holder->is_in_package("java/lang/invoke") || holder->is_in_package("sun/invoke"))
     return true;
   // Trust Atomic*FieldUpdaters: they are very important for performance, and make up one
   // more reason not to use Unsafe, if their final fields are trusted. See more in JDK-8140483.
   if (holder->name() == ciSymbol::java_util_concurrent_atomic_AtomicIntegerFieldUpdater_Impl() ||
       holder->name() == ciSymbol::java_util_concurrent_atomic_AtomicLongFieldUpdater_CASUpdater() ||
       holder->name() == ciSymbol::java_util_concurrent_atomic_AtomicLongFieldUpdater_LockedUpdater() ||
       holder->name() == ciSymbol::java_util_concurrent_atomic_AtomicReferenceFieldUpdater_Impl()) {
     return true;
   }
   return TrustFinalNonStaticFields;
 }
 void ciField::initialize_from(fieldDescriptor* fd) {
   // Get the flags, offset, and canonical holder of the field.
   _flags = ciFlags(fd->access_flags());
   _offset = fd->offset();
   _holder = CURRENT_ENV->get_instance_klass(fd->field_holder());
   // Check to see if the field is constant.
   bool is_final = this->is_final();
   bool is_stable = FoldStableValues && this->is_stable();
   if (_holder->is_initialized() && ((is_final && !has_initialized_final_update()) || is_stable)) {
     if (!this->is_static()) {
       // A field can be constant if it's a final static field or if
       // it's a final non-static field of a trusted class (classes in
       // java.lang.invoke and sun.invoke packages and subpackages).
       if (is_stable || trust_final_non_static_fields(_holder)) {
         _is_constant = true;
         return;
       }
       _is_constant = false;
       return;
     }
     // This field just may be constant.  The only cases where it will
     // not be constant are:
     //
     // 1. The field holds a non-perm-space oop.  The field is, strictly
     //    speaking, constant but we cannot embed non-perm-space oops into
     //    generated code.  For the time being we need to consider the
     //    field to be not constant.
     // 2. The field is a *special* static&final field whose value
     //    may change.  The three examples are java.lang.System.in,
     //    java.lang.System.out, and java.lang.System.err.
     KlassHandle k = _holder->get_Klass();
     assert( SystemDictionary::System_klass() != NULL, "Check once per vm");
     if( k() == SystemDictionary::System_klass() ) {
       // Check offsets for case 2: System.in, System.out, or System.err
       if( _offset == java_lang_System::in_offset_in_bytes()  ||
           _offset == java_lang_System::out_offset_in_bytes() ||
           _offset == java_lang_System::err_offset_in_bytes() ) {
         _is_constant = false;
         return;
       }
     }
     Handle mirror = k->java_mirror();
     switch(type()->basic_type()) {
     case T_BYTE:
       _constant_value = ciConstant(type()->basic_type(), mirror->byte_field(_offset));
       break;
     case T_CHAR:
       _constant_value = ciConstant(type()->basic_type(), mirror->char_field(_offset));
       break;
     case T_SHORT:
       _constant_value = ciConstant(type()->basic_type(), mirror->short_field(_offset));
       break;
     case T_BOOLEAN:
       _constant_value = ciConstant(type()->basic_type(), mirror->bool_field(_offset));
       break;
     case T_INT:
       _constant_value = ciConstant(type()->basic_type(), mirror->int_field(_offset));
       break;
     case T_FLOAT:
       _constant_value = ciConstant(mirror->float_field(_offset));
       break;
     case T_DOUBLE:
       _constant_value = ciConstant(mirror->double_field(_offset));
       break;
     case T_LONG:
       _constant_value = ciConstant(mirror->long_field(_offset));
       break;
     case T_OBJECT:
     case T_ARRAY:
       {
         oop o = mirror->obj_field(_offset);
         // A field will be "constant" if it is known always to be
         // a non-null reference to an instance of a particular class,
         // or to a particular array.  This can happen even if the instance
         // or array is not perm.  In such a case, an "unloaded" ciArray
         // or ciInstance is created.  The compiler may be able to use
         // information about the object's class (which is exact) or length.
         if (o == NULL) {
           _constant_value = ciConstant(type()->basic_type(), ciNullObject::make());
         } else {
           _constant_value = ciConstant(type()->basic_type(), CURRENT_ENV->get_object(o));
           assert(_constant_value.as_object() == CURRENT_ENV->get_object(o), "check interning");
         }
       }
     }
     if (is_stable && _constant_value.is_null_or_zero()) {
       // It is not a constant after all; treat it as uninitialized.
       _is_constant = false;
     } else {
       _is_constant = true;
     }
   } else {
     _is_constant = false;
   }
 }
 // ------------------------------------------------------------------
 // ciField::compute_type
 //
 // Lazily compute the type, if it is an instance klass.
 ciType* ciField::compute_type() {
   GUARDED_VM_ENTRY(return compute_type_impl();)
 }
 ciType* ciField::compute_type_impl() {
   ciKlass* type = CURRENT_ENV->get_klass_by_name_impl(_holder, constantPoolHandle(), _signature, false);
   if (!type->is_primitive_type() && is_shared()) {
     // We must not cache a pointer to an unshared type, in a shared field.
     bool type_is_also_shared = false;
     if (type->is_type_array_klass()) {
       type_is_also_shared = true;  // int[] etc. are explicitly bootstrapped
     } else if (type->is_instance_klass()) {
       type_is_also_shared = type->as_instance_klass()->is_shared();
     } else {
       // Currently there is no 'shared' query for array types.
       type_is_also_shared = !ciObjectFactory::is_initialized();
     }
     if (!type_is_also_shared)
       return type;              // Bummer.
   }
   _type = type;
   return type;
 }
 // ------------------------------------------------------------------
 // ciField::will_link
 //
 // Can a specific access to this field be made without causing
 // link errors?
 bool ciField::will_link(ciInstanceKlass* accessing_klass,
                         Bytecodes::Code bc) {
   VM_ENTRY_MARK;
   assert(bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic ||
          bc == Bytecodes::_getfield  || bc == Bytecodes::_putfield,
          "unexpected bytecode");
   if (_offset == -1) {
     // at creation we couldn't link to our holder so we need to
     // maintain that stance, otherwise there's no safe way to use this
     // ciField.
     return false;
   }
   // Check for static/nonstatic mismatch
   bool is_static = (bc == Bytecodes::_getstatic || bc == Bytecodes::_putstatic);
   if (is_static != this->is_static()) {
     return false;
   }
   // Get and put can have different accessibility rules
   bool is_put    = (bc == Bytecodes::_putfield  || bc == Bytecodes::_putstatic);
   if (is_put) {
     if (_known_to_link_with_put == accessing_klass) {
       return true;
     }
   } else {
     if (_known_to_link_with_get == accessing_klass) {
       return true;
     }
   }
   fieldDescriptor result;
   LinkResolver::resolve_field(result, _holder->get_instanceKlass(),
                               _name->get_symbol(), _signature->get_symbol(),
                               accessing_klass->get_Klass(), bc, true, false,
                               KILL_COMPILE_ON_FATAL_(false));
   // update the hit-cache, unless there is a problem with memory scoping:
   if (accessing_klass->is_shared() || !is_shared()) {
     if (is_put) {
       _known_to_link_with_put = accessing_klass;
     } else {
       _known_to_link_with_get = accessing_klass;
     }
   }
   return true;
 }
 // ------------------------------------------------------------------
 // ciField::print
 void ciField::print() {
   tty->print("<ciField name=");
   _holder->print_name();
   tty->print(".");
   _name->print_symbol();
   tty->print(" signature=");
   _signature->print_symbol();
   tty->print(" offset=%d type=", _offset);
   if (_type != NULL)
     _type->print_name();
   else
     tty->print("(reference)");
   tty->print(" flags=%04x", flags().as_int());
   tty->print(" is_constant=%s", bool_to_str(_is_constant));
   if (_is_constant && is_static()) {
     tty->print(" constant_value=");
     _constant_value.print();
   }
   tty->print(">");
 }
 // ------------------------------------------------------------------
 // ciField::print_name_on
 //
 // Print the name of this field
 void ciField::print_name_on(outputStream* st) {
   name()->print_symbol_on(st);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/ci/ciField.cpp@eef07cd490d4 (annotated)

src/share/vm/ci/ciField.cpp