jdk8-mips64-public/hotspot: src/share/vm/classfile/loaderConstraints.cpp@3582bf76420e (annotated)

src/share/vm/classfile/loaderConstraints.cpp@3582bf76420e (annotated)

src/share/vm/classfile/loaderConstraints.cpp

Thu, 27 Jan 2011 16:11:27 -0800

author: coleenp
date: Thu, 27 Jan 2011 16:11:27 -0800
changeset 2497: 3582bf76420e
parent 2314: f95d63e2154a
child 2551: 4f26f535a225
permissions: -rw-r--r--

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

 /*
  * Copyright (c) 2003, 2010, 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/loaderConstraints.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/safepoint.hpp"
 #include "utilities/hashtable.inline.hpp"
 LoaderConstraintTable::LoaderConstraintTable(int nof_buckets)
   : Hashtable<klassOop>(nof_buckets, sizeof(LoaderConstraintEntry)) {};
 LoaderConstraintEntry* LoaderConstraintTable::new_entry(
                                  unsigned int hash, Symbol* name,
                                  klassOop klass, int num_loaders,
                                  int max_loaders) {
   LoaderConstraintEntry* entry;
   entry = (LoaderConstraintEntry*)Hashtable<klassOop>::new_entry(hash, klass);
   entry->set_name(name);
   entry->set_num_loaders(num_loaders);
   entry->set_max_loaders(max_loaders);
   return entry;
 }
 void LoaderConstraintTable::free_entry(LoaderConstraintEntry *entry) {
   // decrement name refcount before freeing
   entry->name()->decrement_refcount();
   Hashtable<klassOop>::free_entry(entry);
 }
 void LoaderConstraintTable::oops_do(OopClosure* f) {
   for (int index = 0; index < table_size(); index++) {
     for (LoaderConstraintEntry* probe = bucket(index);
                                 probe != NULL;
                                 probe = probe->next()) {
       if (probe->klass() != NULL) {
         f->do_oop((oop*)probe->klass_addr());
       }
       for (int n = 0; n < probe->num_loaders(); n++) {
         if (probe->loader(n) != NULL) {
           f->do_oop(probe->loader_addr(n));
         }
       }
     }
   }
 }
 // The loaderConstraintTable must always be accessed with the
 // SystemDictionary lock held. This is true even for readers as
 // entries in the table could be being dynamically resized.
 LoaderConstraintEntry** LoaderConstraintTable::find_loader_constraint(
                                     Symbol* name, Handle loader) {
   unsigned int hash = compute_hash(name);
   int index = hash_to_index(hash);
   LoaderConstraintEntry** pp = bucket_addr(index);
   while (*pp) {
     LoaderConstraintEntry* p = *pp;
     if (p->hash() == hash) {
       if (p->name() == name) {
         for (int i = p->num_loaders() - 1; i >= 0; i--) {
           if (p->loader(i) == loader()) {
             return pp;
           }
         }
       }
     }
     pp = p->next_addr();
   }
   return pp;
 }
 void LoaderConstraintTable::purge_loader_constraints(BoolObjectClosure* is_alive) {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
   // Remove unloaded entries from constraint table
   for (int index = 0; index < table_size(); index++) {
     LoaderConstraintEntry** p = bucket_addr(index);
     while(*p) {
       LoaderConstraintEntry* probe = *p;
       klassOop klass = probe->klass();
       // Remove klass that is no longer alive
       if (klass != NULL && !is_alive->do_object_b(klass)) {
         probe->set_klass(NULL);
         if (TraceLoaderConstraints) {
           ResourceMark rm;
           tty->print_cr("[Purging class object from constraint for name %s,"
                      " loader list:",
                      probe->name()->as_C_string());
           for (int i = 0; i < probe->num_loaders(); i++) {
             tty->print_cr("[   [%d]: %s", i,
                           SystemDictionary::loader_name(probe->loader(i)));
           }
         }
       }
       // Remove entries no longer alive from loader array
       int n = 0;
       while (n < probe->num_loaders()) {
         if (probe->loader(n) != NULL) {
           if (!is_alive->do_object_b(probe->loader(n))) {
             if (TraceLoaderConstraints) {
               ResourceMark rm;
               tty->print_cr("[Purging loader %s from constraint for name %s",
                             SystemDictionary::loader_name(probe->loader(n)),
                             probe->name()->as_C_string()
                             );
             }
             // Compact array
             int num = probe->num_loaders() - 1;
             probe->set_num_loaders(num);
             probe->set_loader(n, probe->loader(num));
             probe->set_loader(num, NULL);
             if (TraceLoaderConstraints) {
               ResourceMark rm;
               tty->print_cr("[New loader list:");
               for (int i = 0; i < probe->num_loaders(); i++) {
                 tty->print_cr("[   [%d]: %s", i,
                               SystemDictionary::loader_name(probe->loader(i)));
               }
             }
             continue;  // current element replaced, so restart without
                        // incrementing n
           }
         }
         n++;
       }
       // Check whether entry should be purged
       if (probe->num_loaders() < 2) {
             if (TraceLoaderConstraints) {
               ResourceMark rm;
               tty->print("[Purging complete constraint for name %s\n",
                          probe->name()->as_C_string());
             }
         // Purge entry
         *p = probe->next();
         FREE_C_HEAP_ARRAY(oop, probe->loaders());
         free_entry(probe);
       } else {
 #ifdef ASSERT
         if (probe->klass() != NULL) {
           assert(is_alive->do_object_b(probe->klass()), "klass should be live");
         }
         for (n = 0; n < probe->num_loaders(); n++) {
           if (probe->loader(n) != NULL) {
             assert(is_alive->do_object_b(probe->loader(n)), "loader should be live");
           }
         }
 #endif
         // Go to next entry
         p = probe->next_addr();
       }
     }
   }
 }
 bool LoaderConstraintTable::add_entry(Symbol* class_name,
                                       klassOop klass1, Handle class_loader1,
                                       klassOop klass2, Handle class_loader2) {
   int failure_code = 0; // encode different reasons for failing
   if (klass1 != NULL && klass2 != NULL && klass1 != klass2) {
     failure_code = 1;
   } else {
     klassOop klass = klass1 != NULL ? klass1 : klass2;
     LoaderConstraintEntry** pp1 = find_loader_constraint(class_name,
                                                          class_loader1);
     if (*pp1 != NULL && (*pp1)->klass() != NULL) {
       if (klass != NULL) {
         if (klass != (*pp1)->klass()) {
           failure_code = 2;
         }
       } else {
         klass = (*pp1)->klass();
       }
     }
     LoaderConstraintEntry** pp2 = find_loader_constraint(class_name,
                                                          class_loader2);
     if (*pp2 != NULL && (*pp2)->klass() != NULL) {
       if (klass != NULL) {
         if (klass != (*pp2)->klass()) {
           failure_code = 3;
         }
       } else {
         klass = (*pp2)->klass();
       }
     }
     if (failure_code == 0) {
       if (*pp1 == NULL && *pp2 == NULL) {
         unsigned int hash = compute_hash(class_name);
         int index = hash_to_index(hash);
         LoaderConstraintEntry* p;
         p = new_entry(hash, class_name, klass, 2, 2);
         p->set_loaders(NEW_C_HEAP_ARRAY(oop, 2));
         p->set_loader(0, class_loader1());
         p->set_loader(1, class_loader2());
         p->set_klass(klass);
         p->set_next(bucket(index));
         set_entry(index, p);
         if (TraceLoaderConstraints) {
           ResourceMark rm;
           tty->print("[Adding new constraint for name: %s, loader[0]: %s,"
                      " loader[1]: %s ]\n",
                      class_name->as_C_string(),
                      SystemDictionary::loader_name(class_loader1()),
                      SystemDictionary::loader_name(class_loader2())
                      );
         }
       } else if (*pp1 == *pp2) {
         /* constraint already imposed */
         if ((*pp1)->klass() == NULL) {
           (*pp1)->set_klass(klass);
           if (TraceLoaderConstraints) {
             ResourceMark rm;
             tty->print("[Setting class object in existing constraint for"
                        " name: %s and loader %s ]\n",
                        class_name->as_C_string(),
                        SystemDictionary::loader_name(class_loader1())
                        );
           }
         } else {
           assert((*pp1)->klass() == klass, "loader constraints corrupted");
         }
       } else if (*pp1 == NULL) {
         extend_loader_constraint(*pp2, class_loader1, klass);
       } else if (*pp2 == NULL) {
         extend_loader_constraint(*pp1, class_loader2, klass);
       } else {
         merge_loader_constraints(pp1, pp2, klass);
       }
     }
   }
   if (failure_code != 0 && TraceLoaderConstraints) {
     ResourceMark rm;
     const char* reason = "";
     switch(failure_code) {
     case 1: reason = "the class objects presented by loader[0] and loader[1]"
               " are different"; break;
     case 2: reason = "the class object presented by loader[0] does not match"
               " the stored class object in the constraint"; break;
     case 3: reason = "the class object presented by loader[1] does not match"
               " the stored class object in the constraint"; break;
     default: reason = "unknown reason code";
     }
     tty->print("[Failed to add constraint for name: %s, loader[0]: %s,"
                " loader[1]: %s, Reason: %s ]\n",
                class_name->as_C_string(),
                SystemDictionary::loader_name(class_loader1()),
                SystemDictionary::loader_name(class_loader2()),
                reason
                );
   }
   return failure_code == 0;
 }
 // return true if the constraint was updated, false if the constraint is
 // violated
 bool LoaderConstraintTable::check_or_update(instanceKlassHandle k,
                                                    Handle loader,
                                                    Symbol* name) {
   LoaderConstraintEntry* p = *(find_loader_constraint(name, loader));
   if (p && p->klass() != NULL && p->klass() != k()) {
     if (TraceLoaderConstraints) {
       ResourceMark rm;
       tty->print("[Constraint check failed for name %s, loader %s: "
                  "the presented class object differs from that stored ]\n",
                  name->as_C_string(),
                  SystemDictionary::loader_name(loader()));
     }
     return false;
   } else {
     if (p && p->klass() == NULL) {
       p->set_klass(k());
       if (TraceLoaderConstraints) {
         ResourceMark rm;
         tty->print("[Updating constraint for name %s, loader %s, "
                    "by setting class object ]\n",
                    name->as_C_string(),
                    SystemDictionary::loader_name(loader()));
       }
     }
     return true;
   }
 }
 klassOop LoaderConstraintTable::find_constrained_klass(Symbol* name,
                                                        Handle loader) {
   LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
   if (p != NULL && p->klass() != NULL)
     return p->klass();
   // No constraints, or else no klass loaded yet.
   return NULL;
 }
 void LoaderConstraintTable::ensure_loader_constraint_capacity(
                                                      LoaderConstraintEntry *p,
                                                     int nfree) {
     if (p->max_loaders() - p->num_loaders() < nfree) {
         int n = nfree + p->num_loaders();
         oop* new_loaders = NEW_C_HEAP_ARRAY(oop, n);
         memcpy(new_loaders, p->loaders(), sizeof(oop) * p->num_loaders());
         p->set_max_loaders(n);
         FREE_C_HEAP_ARRAY(oop, p->loaders());
         p->set_loaders(new_loaders);
     }
 }
 void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p,
                                                      Handle loader,
                                                      klassOop klass) {
   ensure_loader_constraint_capacity(p, 1);
   int num = p->num_loaders();
   p->set_loader(num, loader());
   p->set_num_loaders(num + 1);
   if (TraceLoaderConstraints) {
     ResourceMark rm;
     tty->print("[Extending constraint for name %s by adding loader[%d]: %s %s",
                p->name()->as_C_string(),
                num,
                SystemDictionary::loader_name(loader()),
                (p->klass() == NULL ? " and setting class object ]\n" : " ]\n")
                );
   }
   if (p->klass() == NULL) {
     p->set_klass(klass);
   } else {
     assert(klass == NULL || p->klass() == klass, "constraints corrupted");
   }
 }
 void LoaderConstraintTable::merge_loader_constraints(
                                                    LoaderConstraintEntry** pp1,
                                                    LoaderConstraintEntry** pp2,
                                                    klassOop klass) {
   // make sure *pp1 has higher capacity
   if ((*pp1)->max_loaders() < (*pp2)->max_loaders()) {
     LoaderConstraintEntry** tmp = pp2;
     pp2 = pp1;
     pp1 = tmp;
   }
   LoaderConstraintEntry* p1 = *pp1;
   LoaderConstraintEntry* p2 = *pp2;
   ensure_loader_constraint_capacity(p1, p2->num_loaders());
   for (int i = 0; i < p2->num_loaders(); i++) {
     int num = p1->num_loaders();
     p1->set_loader(num, p2->loader(i));
     p1->set_num_loaders(num + 1);
   }
   if (TraceLoaderConstraints) {
     ResourceMark rm;
     tty->print_cr("[Merged constraints for name %s, new loader list:",
                   p1->name()->as_C_string()
                   );
     for (int i = 0; i < p1->num_loaders(); i++) {
       tty->print_cr("[   [%d]: %s", i,
                     SystemDictionary::loader_name(p1->loader(i)));
     }
     if (p1->klass() == NULL) {
       tty->print_cr("[... and setting class object]");
     }
   }
   // p1->klass() will hold NULL if klass, p2->klass(), and old
   // p1->klass() are all NULL.  In addition, all three must have
   // matching non-NULL values, otherwise either the constraints would
   // have been violated, or the constraints had been corrupted (and an
   // assertion would fail).
   if (p2->klass() != NULL) {
     assert(p2->klass() == klass, "constraints corrupted");
   }
   if (p1->klass() == NULL) {
     p1->set_klass(klass);
   } else {
     assert(p1->klass() == klass, "constraints corrupted");
   }
   *pp2 = p2->next();
   FREE_C_HEAP_ARRAY(oop, p2->loaders());
   free_entry(p2);
   return;
 }
 void LoaderConstraintTable::verify(Dictionary* dictionary,
                                    PlaceholderTable* placeholders) {
   Thread *thread = Thread::current();
   for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
     for (LoaderConstraintEntry* probe = bucket(cindex);
                                 probe != NULL;
                                 probe = probe->next()) {
       if (probe->klass() != NULL) {
         instanceKlass* ik = instanceKlass::cast(probe->klass());
         guarantee(ik->name() == probe->name(), "name should match");
         Symbol* name = ik->name();
         Handle loader(thread, ik->class_loader());
         unsigned int d_hash = dictionary->compute_hash(name, loader);
         int d_index = dictionary->hash_to_index(d_hash);
         klassOop k = dictionary->find_class(d_index, d_hash, name, loader);
         if (k != NULL) {
           // We found the class in the system dictionary, so we should
           // make sure that the klassOop matches what we already have.
           guarantee(k == probe->klass(), "klass should be in dictionary");
         } else {
           // If we don't find the class in the system dictionary, it
           // has to be in the placeholders table.
           unsigned int p_hash = placeholders->compute_hash(name, loader);
           int p_index = placeholders->hash_to_index(p_hash);
           PlaceholderEntry* entry = placeholders->get_entry(p_index, p_hash,
                                                             name, loader);
           // The instanceKlass might not be on the entry, so the only
           // thing we can check here is whether we were successful in
           // finding the class in the placeholders table.
           guarantee(entry != NULL, "klass should be in the placeholders");
         }
       }
       for (int n = 0; n< probe->num_loaders(); n++) {
         guarantee(probe->loader(n)->is_oop_or_null(), "should be oop");
       }
     }
   }
 }
 #ifndef PRODUCT
 // Called with the system dictionary lock held
 void LoaderConstraintTable::print() {
   ResourceMark rm;
   assert_locked_or_safepoint(SystemDictionary_lock);
   tty->print_cr("Java loader constraints (entries=%d)", _loader_constraint_size);
   for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
     for (LoaderConstraintEntry* probe = bucket(cindex);
                                 probe != NULL;
                                 probe = probe->next()) {
       tty->print("%4d: ", cindex);
       probe->name()->print();
       tty->print(" , loaders:");
       for (int n = 0; n < probe->num_loaders(); n++) {
         probe->loader(n)->print_value();
         tty->print(", ");
       }
       tty->cr();
     }
   }
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/classfile/loaderConstraints.cpp@3582bf76420e (annotated)

src/share/vm/classfile/loaderConstraints.cpp