jdk8-mips64-public/hotspot: src/share/vm/oops/klassVtable.cpp@f258c5828eb8 (annotated)

src/share/vm/oops/klassVtable.cpp@f258c5828eb8 (annotated)

src/share/vm/oops/klassVtable.cpp

Mon, 29 Apr 2013 16:13:57 -0400

author: hseigel
date: Mon, 29 Apr 2013 16:13:57 -0400
changeset 4987: f258c5828eb8
parent 4840: cd3089a56438
child 4998: 08236d966eea
permissions: -rw-r--r--

8011773: Some tests on Interned String crashed JVM with OOM
Summary: Instead of terminating the VM, throw OutOfMemoryError exceptions.
Reviewed-by: coleenp, dholmes

 /*
  * Copyright (c) 1997, 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 "classfile/systemDictionary.hpp"
 #include "classfile/vmSymbols.hpp"
 #include "gc_implementation/shared/markSweep.inline.hpp"
 #include "memory/gcLocker.hpp"
 #include "memory/resourceArea.hpp"
 #include "memory/universe.inline.hpp"
 #include "oops/instanceKlass.hpp"
 #include "oops/klassVtable.hpp"
 #include "oops/method.hpp"
 #include "oops/objArrayOop.hpp"
 #include "oops/oop.inline.hpp"
 #include "prims/jvmtiRedefineClassesTrace.hpp"
 #include "runtime/arguments.hpp"
 #include "runtime/handles.inline.hpp"
 #include "utilities/copy.hpp"
 inline InstanceKlass* klassVtable::ik() const {
   Klass* k = _klass();
   assert(k->oop_is_instance(), "not an InstanceKlass");
   return (InstanceKlass*)k;
 }
 // this function computes the vtable size (including the size needed for miranda
 // methods) and the number of miranda methods in this class
 // Note on Miranda methods: Let's say there is a class C that implements
 // interface I.  Let's say there is a method m in I that neither C nor any
 // of its super classes implement (i.e there is no method of any access, with
 // the same name and signature as m), then m is a Miranda method which is
 // entered as a public abstract method in C's vtable.  From then on it should
 // treated as any other public method in C for method over-ride purposes.
 void klassVtable::compute_vtable_size_and_num_mirandas(
     int* vtable_length_ret, int* num_new_mirandas,
     GrowableArray<Method*>* all_mirandas, Klass* super,
     Array<Method*>* methods, AccessFlags class_flags,
     Handle classloader, Symbol* classname, Array<Klass*>* local_interfaces,
     TRAPS) {
   No_Safepoint_Verifier nsv;
   // set up default result values
   int vtable_length = 0;
   // start off with super's vtable length
   InstanceKlass* sk = (InstanceKlass*)super;
   vtable_length = super == NULL ? 0 : sk->vtable_length();
   // go thru each method in the methods table to see if it needs a new entry
   int len = methods->length();
   for (int i = 0; i < len; i++) {
     assert(methods->at(i)->is_method(), "must be a Method*");
     methodHandle mh(THREAD, methods->at(i));
     if (needs_new_vtable_entry(mh, super, classloader, classname, class_flags, THREAD)) {
       vtable_length += vtableEntry::size(); // we need a new entry
     }
   }
   GrowableArray<Method*> new_mirandas(20);
   // compute the number of mirandas methods that must be added to the end
   get_mirandas(&new_mirandas, all_mirandas, super, methods, local_interfaces);
   *num_new_mirandas = new_mirandas.length();
   vtable_length += *num_new_mirandas * vtableEntry::size();
   if (Universe::is_bootstrapping() && vtable_length == 0) {
     // array classes don't have their superclass set correctly during
     // bootstrapping
     vtable_length = Universe::base_vtable_size();
   }
   if (super == NULL && !Universe::is_bootstrapping() &&
       vtable_length != Universe::base_vtable_size()) {
     // Someone is attempting to redefine java.lang.Object incorrectly.  The
     // only way this should happen is from
     // SystemDictionary::resolve_from_stream(), which will detect this later
     // and throw a security exception.  So don't assert here to let
     // the exception occur.
     vtable_length = Universe::base_vtable_size();
   }
   assert(super != NULL || vtable_length == Universe::base_vtable_size(),
          "bad vtable size for class Object");
   assert(vtable_length % vtableEntry::size() == 0, "bad vtable length");
   assert(vtable_length >= Universe::base_vtable_size(), "vtable too small");
   *vtable_length_ret = vtable_length;
 }
 int klassVtable::index_of(Method* m, int len) const {
   assert(m->vtable_index() >= 0, "do not ask this of non-vtable methods");
   return m->vtable_index();
 }
 int klassVtable::initialize_from_super(KlassHandle super) {
   if (super.is_null()) {
     return 0;
   } else {
     // copy methods from superKlass
     // can't inherit from array class, so must be InstanceKlass
     assert(super->oop_is_instance(), "must be instance klass");
     InstanceKlass* sk = (InstanceKlass*)super();
     klassVtable* superVtable = sk->vtable();
     assert(superVtable->length() <= _length, "vtable too short");
 #ifdef ASSERT
     superVtable->verify(tty, true);
 #endif
     superVtable->copy_vtable_to(table());
 #ifndef PRODUCT
     if (PrintVtables && Verbose) {
       ResourceMark rm;
       tty->print_cr("copy vtable from %s to %s size %d", sk->internal_name(), klass()->internal_name(), _length);
     }
 #endif
     return superVtable->length();
   }
 }
 // Revised lookup semantics   introduced 1.3 (Kestral beta)
 void klassVtable::initialize_vtable(bool checkconstraints, TRAPS) {
   // Note:  Arrays can have intermediate array supers.  Use java_super to skip them.
   KlassHandle super (THREAD, klass()->java_super());
   int nofNewEntries = 0;
   if (PrintVtables && !klass()->oop_is_array()) {
     ResourceMark rm(THREAD);
     tty->print_cr("Initializing: %s", _klass->name()->as_C_string());
   }
 #ifdef ASSERT
   oop* end_of_obj = (oop*)_klass() + _klass()->size();
   oop* end_of_vtable = (oop*)&table()[_length];
   assert(end_of_vtable <= end_of_obj, "vtable extends beyond end");
 #endif
   if (Universe::is_bootstrapping()) {
     // just clear everything
     for (int i = 0; i < _length; i++) table()[i].clear();
     return;
   }
   int super_vtable_len = initialize_from_super(super);
   if (klass()->oop_is_array()) {
     assert(super_vtable_len == _length, "arrays shouldn't introduce new methods");
   } else {
     assert(_klass->oop_is_instance(), "must be InstanceKlass");
     Array<Method*>* methods = ik()->methods();
     int len = methods->length();
     int initialized = super_vtable_len;
     // update_inherited_vtable can stop for gc - ensure using handles
     for (int i = 0; i < len; i++) {
       HandleMark hm(THREAD);
       assert(methods->at(i)->is_method(), "must be a Method*");
       methodHandle mh(THREAD, methods->at(i));
       bool needs_new_entry = update_inherited_vtable(ik(), mh, super_vtable_len, checkconstraints, CHECK);
       if (needs_new_entry) {
         put_method_at(mh(), initialized);
         mh()->set_vtable_index(initialized); // set primary vtable index
         initialized++;
       }
     }
     // add miranda methods; it will also update the value of initialized
     fill_in_mirandas(&initialized);
     // In class hierarchies where the accessibility is not increasing (i.e., going from private ->
     // package_private -> publicprotected), the vtable might actually be smaller than our initial
     // calculation.
     assert(initialized <= _length, "vtable initialization failed");
     for(;initialized < _length; initialized++) {
       put_method_at(NULL, initialized);
     }
     NOT_PRODUCT(verify(tty, true));
   }
 }
 // Called for cases where a method does not override its superclass' vtable entry
 // For bytecodes not produced by javac together it is possible that a method does not override
 // the superclass's method, but might indirectly override a super-super class's vtable entry
 // If none found, return a null superk, else return the superk of the method this does override
 InstanceKlass* klassVtable::find_transitive_override(InstanceKlass* initialsuper, methodHandle target_method,
                             int vtable_index, Handle target_loader, Symbol* target_classname, Thread * THREAD) {
   InstanceKlass* superk = initialsuper;
   while (superk != NULL && superk->super() != NULL) {
     InstanceKlass* supersuperklass = InstanceKlass::cast(superk->super());
     klassVtable* ssVtable = supersuperklass->vtable();
     if (vtable_index < ssVtable->length()) {
       Method* super_method = ssVtable->method_at(vtable_index);
 #ifndef PRODUCT
       Symbol* name= target_method()->name();
       Symbol* signature = target_method()->signature();
       assert(super_method->name() == name && super_method->signature() == signature, "vtable entry name/sig mismatch");
 #endif
       if (supersuperklass->is_override(super_method, target_loader, target_classname, THREAD)) {
 #ifndef PRODUCT
         if (PrintVtables && Verbose) {
           ResourceMark rm(THREAD);
           tty->print("transitive overriding superclass %s with %s::%s index %d, original flags: ",
            supersuperklass->internal_name(),
            _klass->internal_name(), (target_method() != NULL) ?
            target_method()->name()->as_C_string() : "<NULL>", vtable_index);
            super_method->access_flags().print_on(tty);
            tty->print("overriders flags: ");
            target_method->access_flags().print_on(tty);
            tty->cr();
         }
 #endif /*PRODUCT*/
         break; // return found superk
       }
     } else  {
       // super class has no vtable entry here, stop transitive search
       superk = (InstanceKlass*)NULL;
       break;
     }
     // if no override found yet, continue to search up
     superk = InstanceKlass::cast(superk->super());
   }
   return superk;
 }
 // Methods that are "effectively" final don't need vtable entries.
 bool method_is_effectively_final(
     AccessFlags klass_flags, methodHandle target) {
   return target->is_final() || klass_flags.is_final() && !target->is_overpass();
 }
 // Update child's copy of super vtable for overrides
 // OR return true if a new vtable entry is required
 // Only called for InstanceKlass's, i.e. not for arrays
 // If that changed, could not use _klass as handle for klass
 bool klassVtable::update_inherited_vtable(InstanceKlass* klass, methodHandle target_method, int super_vtable_len,
                   bool checkconstraints, TRAPS) {
   ResourceMark rm;
   bool allocate_new = true;
   assert(klass->oop_is_instance(), "must be InstanceKlass");
   // Initialize the method's vtable index to "nonvirtual".
   // If we allocate a vtable entry, we will update it to a non-negative number.
   target_method()->set_vtable_index(Method::nonvirtual_vtable_index);
   // Static and <init> methods are never in
   if (target_method()->is_static() || target_method()->name() ==  vmSymbols::object_initializer_name()) {
     return false;
   }
   if (method_is_effectively_final(klass->access_flags(), target_method)) {
     // a final method never needs a new entry; final methods can be statically
     // resolved and they have to be present in the vtable only if they override
     // a super's method, in which case they re-use its entry
     allocate_new = false;
   }
   // we need a new entry if there is no superclass
   if (klass->super() == NULL) {
     return allocate_new;
   }
   // private methods always have a new entry in the vtable
   // specification interpretation since classic has
   // private methods not overriding
   if (target_method()->is_private()) {
     return allocate_new;
   }
   // search through the vtable and update overridden entries
   // Since check_signature_loaders acquires SystemDictionary_lock
   // which can block for gc, once we are in this loop, use handles
   // For classfiles built with >= jdk7, we now look for transitive overrides
   Symbol* name = target_method()->name();
   Symbol* signature = target_method()->signature();
   Handle target_loader(THREAD, _klass()->class_loader());
   Symbol*  target_classname = _klass->name();
   for(int i = 0; i < super_vtable_len; i++) {
     Method* super_method = method_at(i);
     // Check if method name matches
     if (super_method->name() == name && super_method->signature() == signature) {
       // get super_klass for method_holder for the found method
       InstanceKlass* super_klass =  super_method->method_holder();
       if ((super_klass->is_override(super_method, target_loader, target_classname, THREAD)) ||
       ((klass->major_version() >= VTABLE_TRANSITIVE_OVERRIDE_VERSION)
         && ((super_klass = find_transitive_override(super_klass, target_method, i, target_loader,
              target_classname, THREAD)) != (InstanceKlass*)NULL))) {
         // overriding, so no new entry
         allocate_new = false;
         if (checkconstraints) {
         // Override vtable entry if passes loader constraint check
         // if loader constraint checking requested
         // No need to visit his super, since he and his super
         // have already made any needed loader constraints.
         // Since loader constraints are transitive, it is enough
         // to link to the first super, and we get all the others.
           Handle super_loader(THREAD, super_klass->class_loader());
           if (target_loader() != super_loader()) {
             ResourceMark rm(THREAD);
             Symbol* failed_type_symbol =
               SystemDictionary::check_signature_loaders(signature, target_loader,
                                                         super_loader, true,
                                                         CHECK_(false));
             if (failed_type_symbol != NULL) {
               const char* msg = "loader constraint violation: when resolving "
                 "overridden method \"%s\" the class loader (instance"
                 " of %s) of the current class, %s, and its superclass loader "
                 "(instance of %s), have different Class objects for the type "
                 "%s used in the signature";
               char* sig = target_method()->name_and_sig_as_C_string();
               const char* loader1 = SystemDictionary::loader_name(target_loader());
               char* current = _klass->name()->as_C_string();
               const char* loader2 = SystemDictionary::loader_name(super_loader());
               char* failed_type_name = failed_type_symbol->as_C_string();
               size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
                 strlen(current) + strlen(loader2) + strlen(failed_type_name);
               char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
               jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
                            failed_type_name);
               THROW_MSG_(vmSymbols::java_lang_LinkageError(), buf, false);
             }
           }
        }
         put_method_at(target_method(), i);
         target_method()->set_vtable_index(i);
 #ifndef PRODUCT
         if (PrintVtables && Verbose) {
           tty->print("overriding with %s::%s index %d, original flags: ",
            _klass->internal_name(), (target_method() != NULL) ?
            target_method()->name()->as_C_string() : "<NULL>", i);
            super_method->access_flags().print_on(tty);
            tty->print("overriders flags: ");
            target_method->access_flags().print_on(tty);
            tty->cr();
         }
 #endif /*PRODUCT*/
       } else {
         // allocate_new = true; default. We might override one entry,
         // but not override another. Once we override one, not need new
 #ifndef PRODUCT
         if (PrintVtables && Verbose) {
           tty->print("NOT overriding with %s::%s index %d, original flags: ",
            _klass->internal_name(), (target_method() != NULL) ?
            target_method()->name()->as_C_string() : "<NULL>", i);
            super_method->access_flags().print_on(tty);
            tty->print("overriders flags: ");
            target_method->access_flags().print_on(tty);
            tty->cr();
         }
 #endif /*PRODUCT*/
       }
     }
   }
   return allocate_new;
 }
 void klassVtable::put_method_at(Method* m, int index) {
 #ifndef PRODUCT
   if (PrintVtables && Verbose) {
     ResourceMark rm;
     tty->print_cr("adding %s::%s at index %d", _klass->internal_name(),
       (m != NULL) ? m->name()->as_C_string() : "<NULL>", index);
   }
 #endif
   table()[index].set(m);
 }
 // Find out if a method "m" with superclass "super", loader "classloader" and
 // name "classname" needs a new vtable entry.  Let P be a class package defined
 // by "classloader" and "classname".
 // NOTE: The logic used here is very similar to the one used for computing
 // the vtables indices for a method. We cannot directly use that function because,
 // we allocate the InstanceKlass at load time, and that requires that the
 // superclass has been loaded.
 // However, the vtable entries are filled in at link time, and therefore
 // the superclass' vtable may not yet have been filled in.
 bool klassVtable::needs_new_vtable_entry(methodHandle target_method,
                                          Klass* super,
                                          Handle classloader,
                                          Symbol* classname,
                                          AccessFlags class_flags,
                                          TRAPS) {
   if (method_is_effectively_final(class_flags, target_method) ||
       // a final method never needs a new entry; final methods can be statically
       // resolved and they have to be present in the vtable only if they override
       // a super's method, in which case they re-use its entry
       (target_method()->is_static()) ||
       // static methods don't need to be in vtable
       (target_method()->name() ==  vmSymbols::object_initializer_name())
       // <init> is never called dynamically-bound
       ) {
     return false;
   }
   // we need a new entry if there is no superclass
   if (super == NULL) {
     return true;
   }
   // private methods always have a new entry in the vtable
   // specification interpretation since classic has
   // private methods not overriding
   if (target_method()->is_private()) {
     return true;
   }
   // search through the super class hierarchy to see if we need
   // a new entry
   ResourceMark rm;
   Symbol* name = target_method()->name();
   Symbol* signature = target_method()->signature();
   Klass* k = super;
   Method* super_method = NULL;
   InstanceKlass *holder = NULL;
   Method* recheck_method =  NULL;
   while (k != NULL) {
     // lookup through the hierarchy for a method with matching name and sign.
     super_method = InstanceKlass::cast(k)->lookup_method(name, signature);
     if (super_method == NULL) {
       break; // we still have to search for a matching miranda method
     }
     // get the class holding the matching method
     // make sure you use that class for is_override
     InstanceKlass* superk = super_method->method_holder();
     // we want only instance method matches
     // pretend private methods are not in the super vtable
     // since we do override around them: e.g. a.m pub/b.m private/c.m pub,
     // ignore private, c.m pub does override a.m pub
     // For classes that were not javac'd together, we also do transitive overriding around
     // methods that have less accessibility
     if ((!super_method->is_static()) &&
        (!super_method->is_private())) {
       if (superk->is_override(super_method, classloader, classname, THREAD)) {
         return false;
       // else keep looking for transitive overrides
       }
     }
     // Start with lookup result and continue to search up
     k = superk->super(); // haven't found an override match yet; continue to look
   }
   // if the target method is public or protected it may have a matching
   // miranda method in the super, whose entry it should re-use.
   // Actually, to handle cases that javac would not generate, we need
   // this check for all access permissions.
   InstanceKlass *sk = InstanceKlass::cast(super);
   if (sk->has_miranda_methods()) {
     if (sk->lookup_method_in_all_interfaces(name, signature) != NULL) {
       return false;  // found a matching miranda; we do not need a new entry
     }
   }
   return true; // found no match; we need a new entry
 }
 // Support for miranda methods
 // get the vtable index of a miranda method with matching "name" and "signature"
 int klassVtable::index_of_miranda(Symbol* name, Symbol* signature) {
   // search from the bottom, might be faster
   for (int i = (length() - 1); i >= 0; i--) {
     Method* m = table()[i].method();
     if (is_miranda_entry_at(i) &&
         m->name() == name && m->signature() == signature) {
       return i;
     }
   }
   return Method::invalid_vtable_index;
 }
 // check if an entry is miranda
 bool klassVtable::is_miranda_entry_at(int i) {
   Method* m = method_at(i);
   Klass* method_holder = m->method_holder();
   InstanceKlass *mhk = InstanceKlass::cast(method_holder);
   // miranda methods are interface methods in a class's vtable
   if (mhk->is_interface()) {
     assert(m->is_public(), "should be public");
     assert(ik()->implements_interface(method_holder) , "this class should implement the interface");
     assert(is_miranda(m, ik()->methods(), ik()->super()), "should be a miranda_method");
     return true;
   }
   return false;
 }
 // check if a method is a miranda method, given a class's methods table and it's super
 // the caller must make sure that the method belongs to an interface implemented by the class
 bool klassVtable::is_miranda(Method* m, Array<Method*>* class_methods, Klass* super) {
   Symbol* name = m->name();
   Symbol* signature = m->signature();
   if (InstanceKlass::find_method(class_methods, name, signature) == NULL) {
     // did not find it in the method table of the current class
     if (super == NULL) {
       // super doesn't exist
       return true;
     }
     Method* mo = InstanceKlass::cast(super)->lookup_method(name, signature);
     if (mo == NULL || mo->access_flags().is_private() ) {
       // super class hierarchy does not implement it or protection is different
       return true;
     }
   }
   return false;
 }
 void klassVtable::add_new_mirandas_to_lists(
     GrowableArray<Method*>* new_mirandas, GrowableArray<Method*>* all_mirandas,
     Array<Method*>* current_interface_methods, Array<Method*>* class_methods,
     Klass* super) {
   // iterate thru the current interface's method to see if it a miranda
   int num_methods = current_interface_methods->length();
   for (int i = 0; i < num_methods; i++) {
     Method* im = current_interface_methods->at(i);
     bool is_duplicate = false;
     int num_of_current_mirandas = new_mirandas->length();
     // check for duplicate mirandas in different interfaces we implement
     for (int j = 0; j < num_of_current_mirandas; j++) {
       Method* miranda = new_mirandas->at(j);
       if ((im->name() == miranda->name()) &&
           (im->signature() == miranda->signature())) {
         is_duplicate = true;
         break;
       }
     }
     if (!is_duplicate) { // we don't want duplicate miranda entries in the vtable
       if (is_miranda(im, class_methods, super)) { // is it a miranda at all?
         InstanceKlass *sk = InstanceKlass::cast(super);
         // check if it is a duplicate of a super's miranda
         if (sk->lookup_method_in_all_interfaces(im->name(), im->signature()) == NULL) {
           new_mirandas->append(im);
         }
         if (all_mirandas != NULL) {
           all_mirandas->append(im);
         }
       }
     }
   }
 }
 void klassVtable::get_mirandas(GrowableArray<Method*>* new_mirandas,
                                GrowableArray<Method*>* all_mirandas,
                                Klass* super, Array<Method*>* class_methods,
                                Array<Klass*>* local_interfaces) {
   assert((new_mirandas->length() == 0) , "current mirandas must be 0");
   // iterate thru the local interfaces looking for a miranda
   int num_local_ifs = local_interfaces->length();
   for (int i = 0; i < num_local_ifs; i++) {
     InstanceKlass *ik = InstanceKlass::cast(local_interfaces->at(i));
     add_new_mirandas_to_lists(new_mirandas, all_mirandas,
                               ik->methods(), class_methods, super);
     // iterate thru each local's super interfaces
     Array<Klass*>* super_ifs = ik->transitive_interfaces();
     int num_super_ifs = super_ifs->length();
     for (int j = 0; j < num_super_ifs; j++) {
       InstanceKlass *sik = InstanceKlass::cast(super_ifs->at(j));
       add_new_mirandas_to_lists(new_mirandas, all_mirandas,
                                 sik->methods(), class_methods, super);
     }
   }
 }
 // fill in mirandas
 void klassVtable::fill_in_mirandas(int* initialized) {
   GrowableArray<Method*> mirandas(20);
   get_mirandas(&mirandas, NULL, ik()->super(), ik()->methods(),
                ik()->local_interfaces());
   for (int i = 0; i < mirandas.length(); i++) {
     put_method_at(mirandas.at(i), *initialized);
     ++(*initialized);
   }
 }
 void klassVtable::copy_vtable_to(vtableEntry* start) {
   Copy::disjoint_words((HeapWord*)table(), (HeapWord*)start, _length * vtableEntry::size());
 }
 #if INCLUDE_JVMTI
 void klassVtable::adjust_method_entries(Method** old_methods, Method** new_methods,
                                         int methods_length, bool * trace_name_printed) {
   // search the vtable for uses of either obsolete or EMCP methods
   for (int j = 0; j < methods_length; j++) {
     Method* old_method = old_methods[j];
     Method* new_method = new_methods[j];
     // In the vast majority of cases we could get the vtable index
     // by using:  old_method->vtable_index()
     // However, there are rare cases, eg. sun.awt.X11.XDecoratedPeer.getX()
     // in sun.awt.X11.XFramePeer where methods occur more than once in the
     // vtable, so, alas, we must do an exhaustive search.
     for (int index = 0; index < length(); index++) {
       if (unchecked_method_at(index) == old_method) {
         put_method_at(new_method, index);
         if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
           if (!(*trace_name_printed)) {
             // RC_TRACE_MESG macro has an embedded ResourceMark
             RC_TRACE_MESG(("adjust: name=%s",
                            old_method->method_holder()->external_name()));
             *trace_name_printed = true;
           }
           // RC_TRACE macro has an embedded ResourceMark
           RC_TRACE(0x00100000, ("vtable method update: %s(%s)",
                                 new_method->name()->as_C_string(),
                                 new_method->signature()->as_C_string()));
         }
         // cannot 'break' here; see for-loop comment above.
       }
     }
   }
 }
 // a vtable should never contain old or obsolete methods
 bool klassVtable::check_no_old_or_obsolete_entries() {
   for (int i = 0; i < length(); i++) {
     Method* m = unchecked_method_at(i);
     if (m != NULL &&
         (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
       return false;
     }
   }
   return true;
 }
 void klassVtable::dump_vtable() {
   tty->print_cr("vtable dump --");
   for (int i = 0; i < length(); i++) {
     Method* m = unchecked_method_at(i);
     if (m != NULL) {
       tty->print("      (%5d)  ", i);
       m->access_flags().print_on(tty);
       tty->print(" --  ");
       m->print_name(tty);
       tty->cr();
     }
   }
 }
 #endif // INCLUDE_JVMTI
 // CDS/RedefineClasses support - clear vtables so they can be reinitialized
 void klassVtable::clear_vtable() {
   for (int i = 0; i < _length; i++) table()[i].clear();
 }
 bool klassVtable::is_initialized() {
   return _length == 0 || table()[0].method() != NULL;
 }
 //-----------------------------------------------------------------------------------------
 // Itable code
 // Initialize a itableMethodEntry
 void itableMethodEntry::initialize(Method* m) {
   if (m == NULL) return;
   _method = m;
 }
 klassItable::klassItable(instanceKlassHandle klass) {
   _klass = klass;
   if (klass->itable_length() > 0) {
     itableOffsetEntry* offset_entry = (itableOffsetEntry*)klass->start_of_itable();
     if (offset_entry  != NULL && offset_entry->interface_klass() != NULL) { // Check that itable is initialized
       // First offset entry points to the first method_entry
       intptr_t* method_entry  = (intptr_t *)(((address)klass()) + offset_entry->offset());
       intptr_t* end         = klass->end_of_itable();
       _table_offset      = (intptr_t*)offset_entry - (intptr_t*)klass();
       _size_offset_table = (method_entry - ((intptr_t*)offset_entry)) / itableOffsetEntry::size();
       _size_method_table = (end - method_entry)                  / itableMethodEntry::size();
       assert(_table_offset >= 0 && _size_offset_table >= 0 && _size_method_table >= 0, "wrong computation");
       return;
     }
   }
   // The length of the itable was either zero, or it has not yet been initialized.
   _table_offset      = 0;
   _size_offset_table = 0;
   _size_method_table = 0;
 }
 static int initialize_count = 0;
 // Initialization
 void klassItable::initialize_itable(bool checkconstraints, TRAPS) {
   // Cannot be setup doing bootstrapping, interfaces don't have
   // itables, and klass with only ones entry have empty itables
   if (Universe::is_bootstrapping() ||
       _klass->is_interface() ||
       _klass->itable_length() == itableOffsetEntry::size()) return;
   // There's alway an extra itable entry so we can null-terminate it.
   guarantee(size_offset_table() >= 1, "too small");
   int num_interfaces = size_offset_table() - 1;
   if (num_interfaces > 0) {
     if (TraceItables) tty->print_cr("%3d: Initializing itables for %s", ++initialize_count,
                                     _klass->name()->as_C_string());
     // Iterate through all interfaces
     int i;
     for(i = 0; i < num_interfaces; i++) {
       itableOffsetEntry* ioe = offset_entry(i);
       HandleMark hm(THREAD);
       KlassHandle interf_h (THREAD, ioe->interface_klass());
       assert(interf_h() != NULL && ioe->offset() != 0, "bad offset entry in itable");
       initialize_itable_for_interface(ioe->offset(), interf_h, checkconstraints, CHECK);
     }
   }
   // Check that the last entry is empty
   itableOffsetEntry* ioe = offset_entry(size_offset_table() - 1);
   guarantee(ioe->interface_klass() == NULL && ioe->offset() == 0, "terminator entry missing");
 }
 void klassItable::initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS) {
   Array<Method*>* methods = InstanceKlass::cast(interf_h())->methods();
   int nof_methods = methods->length();
   HandleMark hm;
   KlassHandle klass = _klass;
   assert(nof_methods > 0, "at least one method must exist for interface to be in vtable");
   Handle interface_loader (THREAD, InstanceKlass::cast(interf_h())->class_loader());
   int ime_num = 0;
   // Skip first Method* if it is a class initializer
   int i = methods->at(0)->is_static_initializer() ? 1 : 0;
   // m, method_name, method_signature, klass reset each loop so they
   // don't need preserving across check_signature_loaders call
   // methods needs a handle in case of gc from check_signature_loaders
   for(; i < nof_methods; i++) {
     Method* m = methods->at(i);
     Symbol* method_name = m->name();
     Symbol* method_signature = m->signature();
     // This is same code as in Linkresolver::lookup_instance_method_in_klasses
     Method* target = klass->uncached_lookup_method(method_name, method_signature);
     while (target != NULL && target->is_static()) {
       // continue with recursive lookup through the superclass
       Klass* super = target->method_holder()->super();
       target = (super == NULL) ? (Method*)NULL : super->uncached_lookup_method(method_name, method_signature);
     }
     if (target == NULL || !target->is_public() || target->is_abstract()) {
       // Entry do not resolve. Leave it empty
     } else {
       // Entry did resolve, check loader constraints before initializing
       // if checkconstraints requested
       methodHandle  target_h (THREAD, target); // preserve across gc
       if (checkconstraints) {
         Handle method_holder_loader (THREAD, target->method_holder()->class_loader());
         if (method_holder_loader() != interface_loader()) {
           ResourceMark rm(THREAD);
           Symbol* failed_type_symbol =
             SystemDictionary::check_signature_loaders(method_signature,
                                                       method_holder_loader,
                                                       interface_loader,
                                                       true, CHECK);
           if (failed_type_symbol != NULL) {
             const char* msg = "loader constraint violation in interface "
               "itable initialization: when resolving method \"%s\" the class"
               " loader (instance of %s) of the current class, %s, "
               "and the class loader (instance of %s) for interface "
               "%s have different Class objects for the type %s "
               "used in the signature";
             char* sig = target_h()->name_and_sig_as_C_string();
             const char* loader1 = SystemDictionary::loader_name(method_holder_loader());
             char* current = klass->name()->as_C_string();
             const char* loader2 = SystemDictionary::loader_name(interface_loader());
             char* iface = InstanceKlass::cast(interf_h())->name()->as_C_string();
             char* failed_type_name = failed_type_symbol->as_C_string();
             size_t buflen = strlen(msg) + strlen(sig) + strlen(loader1) +
               strlen(current) + strlen(loader2) + strlen(iface) +
               strlen(failed_type_name);
             char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
             jio_snprintf(buf, buflen, msg, sig, loader1, current, loader2,
                          iface, failed_type_name);
             THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
           }
         }
       }
       // ime may have moved during GC so recalculate address
       itableOffsetEntry::method_entry(_klass(), method_table_offset)[ime_num].initialize(target_h());
     }
     // Progress to next entry
     ime_num++;
   }
 }
 // Update entry for specific Method*
 void klassItable::initialize_with_method(Method* m) {
   itableMethodEntry* ime = method_entry(0);
   for(int i = 0; i < _size_method_table; i++) {
     if (ime->method() == m) {
       ime->initialize(m);
     }
     ime++;
   }
 }
 #if INCLUDE_JVMTI
 void klassItable::adjust_method_entries(Method** old_methods, Method** new_methods,
                                         int methods_length, bool * trace_name_printed) {
   // search the itable for uses of either obsolete or EMCP methods
   for (int j = 0; j < methods_length; j++) {
     Method* old_method = old_methods[j];
     Method* new_method = new_methods[j];
     itableMethodEntry* ime = method_entry(0);
     // The itable can describe more than one interface and the same
     // method signature can be specified by more than one interface.
     // This means we have to do an exhaustive search to find all the
     // old_method references.
     for (int i = 0; i < _size_method_table; i++) {
       if (ime->method() == old_method) {
         ime->initialize(new_method);
         if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
           if (!(*trace_name_printed)) {
             // RC_TRACE_MESG macro has an embedded ResourceMark
             RC_TRACE_MESG(("adjust: name=%s",
               old_method->method_holder()->external_name()));
             *trace_name_printed = true;
           }
           // RC_TRACE macro has an embedded ResourceMark
           RC_TRACE(0x00200000, ("itable method update: %s(%s)",
             new_method->name()->as_C_string(),
             new_method->signature()->as_C_string()));
         }
         // cannot 'break' here; see for-loop comment above.
       }
       ime++;
     }
   }
 }
 // an itable should never contain old or obsolete methods
 bool klassItable::check_no_old_or_obsolete_entries() {
   itableMethodEntry* ime = method_entry(0);
   for (int i = 0; i < _size_method_table; i++) {
     Method* m = ime->method();
     if (m != NULL &&
         (NOT_PRODUCT(!m->is_valid() ||) m->is_old() || m->is_obsolete())) {
       return false;
     }
     ime++;
   }
   return true;
 }
 void klassItable::dump_itable() {
   itableMethodEntry* ime = method_entry(0);
   tty->print_cr("itable dump --");
   for (int i = 0; i < _size_method_table; i++) {
     Method* m = ime->method();
     if (m != NULL) {
       tty->print("      (%5d)  ", i);
       m->access_flags().print_on(tty);
       tty->print(" --  ");
       m->print_name(tty);
       tty->cr();
     }
     ime++;
   }
 }
 #endif // INCLUDE_JVMTI
 // Setup
 class InterfaceVisiterClosure : public StackObj {
  public:
   virtual void doit(Klass* intf, int method_count) = 0;
 };
 // Visit all interfaces with at-least one method (excluding <clinit>)
 void visit_all_interfaces(Array<Klass*>* transitive_intf, InterfaceVisiterClosure *blk) {
   // Handle array argument
   for(int i = 0; i < transitive_intf->length(); i++) {
     Klass* intf = transitive_intf->at(i);
     assert(intf->is_interface(), "sanity check");
     // Find no. of methods excluding a <clinit>
     int method_count = InstanceKlass::cast(intf)->methods()->length();
     if (method_count > 0) {
       Method* m = InstanceKlass::cast(intf)->methods()->at(0);
       assert(m != NULL && m->is_method(), "sanity check");
       if (m->name() == vmSymbols::object_initializer_name()) {
         method_count--;
       }
     }
     // Only count interfaces with at least one method
     if (method_count > 0) {
       blk->doit(intf, method_count);
     }
   }
 }
 class CountInterfacesClosure : public InterfaceVisiterClosure {
  private:
   int _nof_methods;
   int _nof_interfaces;
  public:
    CountInterfacesClosure() { _nof_methods = 0; _nof_interfaces = 0; }
    int nof_methods() const    { return _nof_methods; }
    int nof_interfaces() const { return _nof_interfaces; }
    void doit(Klass* intf, int method_count) { _nof_methods += method_count; _nof_interfaces++; }
 };
 class SetupItableClosure : public InterfaceVisiterClosure  {
  private:
   itableOffsetEntry* _offset_entry;
   itableMethodEntry* _method_entry;
   address            _klass_begin;
  public:
   SetupItableClosure(address klass_begin, itableOffsetEntry* offset_entry, itableMethodEntry* method_entry) {
     _klass_begin  = klass_begin;
     _offset_entry = offset_entry;
     _method_entry = method_entry;
   }
   itableMethodEntry* method_entry() const { return _method_entry; }
   void doit(Klass* intf, int method_count) {
     int offset = ((address)_method_entry) - _klass_begin;
     _offset_entry->initialize(intf, offset);
     _offset_entry++;
     _method_entry += method_count;
   }
 };
 int klassItable::compute_itable_size(Array<Klass*>* transitive_interfaces) {
   // Count no of interfaces and total number of interface methods
   CountInterfacesClosure cic;
   visit_all_interfaces(transitive_interfaces, &cic);
   // There's alway an extra itable entry so we can null-terminate it.
   int itable_size = calc_itable_size(cic.nof_interfaces() + 1, cic.nof_methods());
   // Statistics
   update_stats(itable_size * HeapWordSize);
   return itable_size;
 }
 // Fill out offset table and interface klasses into the itable space
 void klassItable::setup_itable_offset_table(instanceKlassHandle klass) {
   if (klass->itable_length() == 0) return;
   assert(!klass->is_interface(), "Should have zero length itable");
   // Count no of interfaces and total number of interface methods
   CountInterfacesClosure cic;
   visit_all_interfaces(klass->transitive_interfaces(), &cic);
   int nof_methods    = cic.nof_methods();
   int nof_interfaces = cic.nof_interfaces();
   // Add one extra entry so we can null-terminate the table
   nof_interfaces++;
   assert(compute_itable_size(klass->transitive_interfaces()) ==
          calc_itable_size(nof_interfaces, nof_methods),
          "mismatch calculation of itable size");
   // Fill-out offset table
   itableOffsetEntry* ioe = (itableOffsetEntry*)klass->start_of_itable();
   itableMethodEntry* ime = (itableMethodEntry*)(ioe + nof_interfaces);
   intptr_t* end               = klass->end_of_itable();
   assert((oop*)(ime + nof_methods) <= (oop*)klass->start_of_nonstatic_oop_maps(), "wrong offset calculation (1)");
   assert((oop*)(end) == (oop*)(ime + nof_methods),                      "wrong offset calculation (2)");
   // Visit all interfaces and initialize itable offset table
   SetupItableClosure sic((address)klass(), ioe, ime);
   visit_all_interfaces(klass->transitive_interfaces(), &sic);
 #ifdef ASSERT
   ime  = sic.method_entry();
   oop* v = (oop*) klass->end_of_itable();
   assert( (oop*)(ime) == v, "wrong offset calculation (2)");
 #endif
 }
 // m must be a method in an interface
 int klassItable::compute_itable_index(Method* m) {
   InstanceKlass* intf = m->method_holder();
   assert(intf->is_interface(), "sanity check");
   Array<Method*>* methods = intf->methods();
   int index = 0;
   while(methods->at(index) != m) {
     index++;
     assert(index < methods->length(), "should find index for resolve_invoke");
   }
   // Adjust for <clinit>, which is left out of table if first method
   if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
     index--;
   }
   return index;
 }
 // inverse to compute_itable_index
 Method* klassItable::method_for_itable_index(Klass* intf, int itable_index) {
   assert(InstanceKlass::cast(intf)->is_interface(), "sanity check");
   Array<Method*>* methods = InstanceKlass::cast(intf)->methods();
   int index = itable_index;
   // Adjust for <clinit>, which is left out of table if first method
   if (methods->length() > 0 && methods->at(0)->is_static_initializer()) {
     index++;
   }
   if (itable_index < 0 || index >= methods->length())
     return NULL;                // help caller defend against bad indexes
   Method* m = methods->at(index);
   assert(compute_itable_index(m) == itable_index, "correct inverse");
   return m;
 }
 void klassVtable::verify(outputStream* st, bool forced) {
   // make sure table is initialized
   if (!Universe::is_fully_initialized()) return;
 #ifndef PRODUCT
   // avoid redundant verifies
   if (!forced && _verify_count == Universe::verify_count()) return;
   _verify_count = Universe::verify_count();
 #endif
   oop* end_of_obj = (oop*)_klass() + _klass()->size();
   oop* end_of_vtable = (oop *)&table()[_length];
   if (end_of_vtable > end_of_obj) {
     fatal(err_msg("klass %s: klass object too short (vtable extends beyond "
                   "end)", _klass->internal_name()));
   }
   for (int i = 0; i < _length; i++) table()[i].verify(this, st);
   // verify consistency with superKlass vtable
   Klass* super = _klass->super();
   if (super != NULL) {
     InstanceKlass* sk = InstanceKlass::cast(super);
     klassVtable* vt = sk->vtable();
     for (int i = 0; i < vt->length(); i++) {
       verify_against(st, vt, i);
     }
   }
 }
 void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
   vtableEntry* vte = &vt->table()[index];
   if (vte->method()->name()      != table()[index].method()->name() ||
       vte->method()->signature() != table()[index].method()->signature()) {
     fatal("mismatched name/signature of vtable entries");
   }
 }
 #ifndef PRODUCT
 void klassVtable::print() {
   ResourceMark rm;
   tty->print("klassVtable for klass %s (length %d):\n", _klass->internal_name(), length());
   for (int i = 0; i < length(); i++) {
     table()[i].print();
     tty->cr();
   }
 }
 #endif
 void vtableEntry::verify(klassVtable* vt, outputStream* st) {
   NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
   assert(method() != NULL, "must have set method");
   method()->verify();
   // we sub_type, because it could be a miranda method
   if (!vt->klass()->is_subtype_of(method()->method_holder())) {
 #ifndef PRODUCT
     print();
 #endif
     fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
   }
 }
 #ifndef PRODUCT
 void vtableEntry::print() {
   ResourceMark rm;
   tty->print("vtableEntry %s: ", method()->name()->as_C_string());
   if (Verbose) {
     tty->print("m %#lx ", (address)method());
   }
 }
 class VtableStats : AllStatic {
  public:
   static int no_klasses;                // # classes with vtables
   static int no_array_klasses;          // # array classes
   static int no_instance_klasses;       // # instanceKlasses
   static int sum_of_vtable_len;         // total # of vtable entries
   static int sum_of_array_vtable_len;   // total # of vtable entries in array klasses only
   static int fixed;                     // total fixed overhead in bytes
   static int filler;                    // overhead caused by filler bytes
   static int entries;                   // total bytes consumed by vtable entries
   static int array_entries;             // total bytes consumed by array vtable entries
   static void do_class(Klass* k) {
     Klass* kl = k;
     klassVtable* vt = kl->vtable();
     if (vt == NULL) return;
     no_klasses++;
     if (kl->oop_is_instance()) {
       no_instance_klasses++;
       kl->array_klasses_do(do_class);
     }
     if (kl->oop_is_array()) {
       no_array_klasses++;
       sum_of_array_vtable_len += vt->length();
     }
     sum_of_vtable_len += vt->length();
   }
   static void compute() {
     SystemDictionary::classes_do(do_class);
     fixed  = no_klasses * oopSize;      // vtable length
     // filler size is a conservative approximation
     filler = oopSize * (no_klasses - no_instance_klasses) * (sizeof(InstanceKlass) - sizeof(ArrayKlass) - 1);
     entries = sizeof(vtableEntry) * sum_of_vtable_len;
     array_entries = sizeof(vtableEntry) * sum_of_array_vtable_len;
   }
 };
 int VtableStats::no_klasses = 0;
 int VtableStats::no_array_klasses = 0;
 int VtableStats::no_instance_klasses = 0;
 int VtableStats::sum_of_vtable_len = 0;
 int VtableStats::sum_of_array_vtable_len = 0;
 int VtableStats::fixed = 0;
 int VtableStats::filler = 0;
 int VtableStats::entries = 0;
 int VtableStats::array_entries = 0;
 void klassVtable::print_statistics() {
   ResourceMark rm;
   HandleMark hm;
   VtableStats::compute();
   tty->print_cr("vtable statistics:");
   tty->print_cr("%6d classes (%d instance, %d array)", VtableStats::no_klasses, VtableStats::no_instance_klasses, VtableStats::no_array_klasses);
   int total = VtableStats::fixed + VtableStats::filler + VtableStats::entries;
   tty->print_cr("%6d bytes fixed overhead (refs + vtable object header)", VtableStats::fixed);
   tty->print_cr("%6d bytes filler overhead", VtableStats::filler);
   tty->print_cr("%6d bytes for vtable entries (%d for arrays)", VtableStats::entries, VtableStats::array_entries);
   tty->print_cr("%6d bytes total", total);
 }
 int  klassItable::_total_classes;   // Total no. of classes with itables
 long klassItable::_total_size;      // Total no. of bytes used for itables
 void klassItable::print_statistics() {
  tty->print_cr("itable statistics:");
  tty->print_cr("%6d classes with itables", _total_classes);
  tty->print_cr("%6d K uses for itables (average by class: %d bytes)", _total_size / K, _total_size / _total_classes);
 }
 #endif // PRODUCT

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/oops/klassVtable.cpp@f258c5828eb8 (annotated)

src/share/vm/oops/klassVtable.cpp