jdk8-mips64-public/hotspot: src/share/vm/memory/dump.cpp@b099aaf51bf8 (annotated)

src/share/vm/memory/dump.cpp@b099aaf51bf8 (annotated)

src/share/vm/memory/dump.cpp

Tue, 22 Mar 2011 13:36:33 -0700

author: jcoomes
date: Tue, 22 Mar 2011 13:36:33 -0700
changeset 2661: b099aaf51bf8
parent 2497: 3582bf76420e
child 2700: 352622fd140a
permissions: -rw-r--r--

6962931: move interned strings out of the perm gen
Reviewed-by: never, coleenp, ysr, jwilhelm

 /*
  * 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/javaClasses.hpp"
 #include "classfile/loaderConstraints.hpp"
 #include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "gc_implementation/shared/spaceDecorator.hpp"
 #include "memory/classify.hpp"
 #include "memory/filemap.hpp"
 #include "memory/oopFactory.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/methodDataOop.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/javaCalls.hpp"
 #include "runtime/signature.hpp"
 #include "runtime/vmThread.hpp"
 #include "runtime/vm_operations.hpp"
 #include "utilities/copy.hpp"
 // Closure to set up the fingerprint field for all methods.
 class FingerprintMethodsClosure: public ObjectClosure {
 public:
   void do_object(oop obj) {
     if (obj->is_method()) {
       methodOop mobj = (methodOop)obj;
       ResourceMark rm;
       (new Fingerprinter(mobj))->fingerprint();
     }
   }
 };
 // Closure to set the hash value (String.hash field) in all of the
 // String objects in the heap.  Setting the hash value is not required.
 // However, setting the value in advance prevents the value from being
 // written later, increasing the likelihood that the shared page contain
 // the hash can be shared.
 //
 // NOTE THAT the algorithm in StringTable::hash_string() MUST MATCH the
 // algorithm in java.lang.String.hashCode().
 class StringHashCodeClosure: public OopClosure {
 private:
   Thread* THREAD;
   int hash_offset;
 public:
   StringHashCodeClosure(Thread* t) {
     THREAD = t;
     hash_offset = java_lang_String::hash_offset_in_bytes();
   }
   void do_oop(oop* p) {
     if (p != NULL) {
       oop obj = *p;
       if (obj->klass() == SystemDictionary::String_klass()) {
         int hash;
         typeArrayOop value = java_lang_String::value(obj);
         int length = java_lang_String::length(obj);
         if (length == 0) {
           hash = 0;
         } else {
           int offset = java_lang_String::offset(obj);
           jchar* s = value->char_at_addr(offset);
           hash = StringTable::hash_string(s, length);
         }
         obj->int_field_put(hash_offset, hash);
       }
     }
   }
   void do_oop(narrowOop* p) { ShouldNotReachHere(); }
 };
 // Remove data from objects which should not appear in the shared file
 // (as it pertains only to the current JVM).
 class RemoveUnshareableInfoClosure : public ObjectClosure {
 public:
   void do_object(oop obj) {
     // Zap data from the objects which is pertains only to this JVM.  We
     // want that data recreated in new JVMs when the shared file is used.
     if (obj->is_method()) {
       ((methodOop)obj)->remove_unshareable_info();
     }
     else if (obj->is_klass()) {
       Klass::cast((klassOop)obj)->remove_unshareable_info();
     }
     // Don't save compiler related special oops (shouldn't be any yet).
     if (obj->is_methodData() || obj->is_compiledICHolder()) {
       ShouldNotReachHere();
     }
   }
 };
 static bool mark_object(oop obj) {
   if (obj != NULL &&
       !obj->is_shared() &&
       !obj->is_forwarded() &&
       !obj->is_gc_marked()) {
     obj->set_mark(markOopDesc::prototype()->set_marked());
     return true;
   }
   return false;
 }
 class MoveSymbols : public SymbolClosure {
 private:
   char* _start;
   char* _end;
   char* _top;
   int _count;
   bool in_shared_space(Symbol* sym) const {
     return (char*)sym >= _start && (char*)sym < _end;
   }
   Symbol* get_shared_copy(Symbol* sym) {
     return sym->refcount() > 0 ? NULL : (Symbol*)(_start - sym->refcount());
   }
   Symbol* make_shared_copy(Symbol* sym) {
     Symbol* new_sym = (Symbol*)_top;
     int size = sym->object_size();
     _top += size * HeapWordSize;
     if (_top <= _end) {
       Copy::disjoint_words((HeapWord*)sym, (HeapWord*)new_sym, size);
       // Encode a reference to the copy as a negative distance from _start
       // When a symbol is being copied to a shared space
       // during CDS archive creation, the original symbol is marked
       // as relocated by putting a negative value to its _refcount field,
       // This value is also used to find where exactly the shared copy is
       // (see MoveSymbols::get_shared_copy), so that the other references
       // to this symbol could be changed to point to the shared copy.
       sym->_refcount = (int)(_start - (char*)new_sym);
       // Mark the symbol in the shared archive as immortal so it is read only
       // and not refcounted.
       new_sym->_refcount = -1;
       _count++;
     } else {
       report_out_of_shared_space(SharedMiscData);
     }
     return new_sym;
   }
 public:
   MoveSymbols(char* top, char* end) :
     _start(top), _end(end), _top(top), _count(0) { }
   char* get_top() const { return _top; }
   int count()     const { return _count; }
   void do_symbol(Symbol** p) {
     Symbol* sym = load_symbol(p);
     if (sym != NULL && !in_shared_space(sym)) {
       Symbol* new_sym = get_shared_copy(sym);
       if (new_sym == NULL) {
         // The symbol has not been relocated yet; copy it to _top address
         assert(sym->refcount() > 0, "should have positive reference count");
         new_sym = make_shared_copy(sym);
       }
       // Make the reference point to the shared copy of the symbol
       store_symbol(p, new_sym);
     }
   }
 };
 // Closure:  mark objects closure.
 class MarkObjectsOopClosure : public OopClosure {
 public:
   void do_oop(oop* p)       { mark_object(*p); }
   void do_oop(narrowOop* p) { ShouldNotReachHere(); }
 };
 class MarkObjectsSkippingKlassesOopClosure : public OopClosure {
 public:
   void do_oop(oop* pobj) {
     oop obj = *pobj;
     if (obj != NULL &&
         !obj->is_klass()) {
       mark_object(obj);
     }
   }
   void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
 };
 static void mark_object_recursive_skipping_klasses(oop obj) {
   mark_object(obj);
   if (obj != NULL) {
     MarkObjectsSkippingKlassesOopClosure mark_all;
     obj->oop_iterate(&mark_all);
   }
 }
 // Closure:  mark common read-only objects
 class MarkCommonReadOnly : public ObjectClosure {
 private:
   MarkObjectsOopClosure mark_all;
 public:
   void do_object(oop obj) {
     // Mark all constMethod objects.
     if (obj->is_constMethod()) {
       mark_object(obj);
       mark_object(constMethodOop(obj)->stackmap_data());
       // Exception tables are needed by ci code during compilation.
       mark_object(constMethodOop(obj)->exception_table());
     }
     // Mark objects referenced by klass objects which are read-only.
     else if (obj->is_klass()) {
       Klass* k = Klass::cast((klassOop)obj);
       mark_object(k->secondary_supers());
       // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
       // it is never modified. Otherwise, they will be pre-marked; the
       // GC marking phase will skip them; and by skipping them will fail
       // to mark the methods objects referenced by the array.
       if (obj->blueprint()->oop_is_instanceKlass()) {
         instanceKlass* ik = instanceKlass::cast((klassOop)obj);
         mark_object(ik->method_ordering());
         mark_object(ik->local_interfaces());
         mark_object(ik->transitive_interfaces());
         mark_object(ik->fields());
         mark_object(ik->class_annotations());
         mark_object_recursive_skipping_klasses(ik->fields_annotations());
         mark_object_recursive_skipping_klasses(ik->methods_annotations());
         mark_object_recursive_skipping_klasses(ik->methods_parameter_annotations());
         mark_object_recursive_skipping_klasses(ik->methods_default_annotations());
         typeArrayOop inner_classes = ik->inner_classes();
         if (inner_classes != NULL) {
           mark_object(inner_classes);
         }
       }
     }
   }
 };
 // Closure:  find symbol references in Java Heap objects
 class CommonSymbolsClosure : public ObjectClosure {
 private:
   SymbolClosure* _closure;
 public:
   CommonSymbolsClosure(SymbolClosure* closure) : _closure(closure) { }
   void do_object(oop obj) {
     // Traverse symbols referenced by method objects.
     if (obj->is_method()) {
       methodOop m = methodOop(obj);
       constantPoolOop constants = m->constants();
       _closure->do_symbol(constants->symbol_at_addr(m->name_index()));
       _closure->do_symbol(constants->symbol_at_addr(m->signature_index()));
     }
     // Traverse symbols referenced by klass objects which are read-only.
     else if (obj->is_klass()) {
       Klass* k = Klass::cast((klassOop)obj);
       k->shared_symbols_iterate(_closure);
       if (obj->blueprint()->oop_is_instanceKlass()) {
         instanceKlass* ik = instanceKlass::cast((klassOop)obj);
         typeArrayOop inner_classes = ik->inner_classes();
         if (inner_classes != NULL) {
           constantPoolOop constants = ik->constants();
           int n = inner_classes->length();
           for (int i = 0; i < n; i += instanceKlass::inner_class_next_offset) {
             int ioff = i + instanceKlass::inner_class_inner_name_offset;
             int index = inner_classes->ushort_at(ioff);
             if (index != 0) {
               _closure->do_symbol(constants->symbol_at_addr(index));
             }
           }
         }
       }
     }
     // Traverse symbols referenced by other constantpool entries.
     else if (obj->is_constantPool()) {
       constantPoolOop(obj)->shared_symbols_iterate(_closure);
     }
   }
 };
 // Closure:  mark char arrays used by strings
 class MarkStringValues : public ObjectClosure {
 private:
   MarkObjectsOopClosure mark_all;
 public:
   void do_object(oop obj) {
     // Character arrays referenced by String objects are read-only.
     if (java_lang_String::is_instance(obj)) {
       mark_object(java_lang_String::value(obj));
     }
   }
 };
 #ifdef DEBUG
 // Closure:  Check for objects left in the heap which have not been moved.
 class CheckRemainingObjects : public ObjectClosure {
 private:
   int count;
 public:
   CheckRemainingObjects() {
     count = 0;
   }
   void do_object(oop obj) {
     if (!obj->is_shared() &&
         !obj->is_forwarded()) {
       ++count;
       if (Verbose) {
         tty->print("Unreferenced object: ");
         obj->print_on(tty);
       }
     }
   }
   void status() {
     tty->print_cr("%d objects no longer referenced, not shared.", count);
   }
 };
 #endif
 // Closure:  Mark remaining objects read-write, except Strings.
 class MarkReadWriteObjects : public ObjectClosure {
 private:
   MarkObjectsOopClosure mark_objects;
 public:
   void do_object(oop obj) {
       // The METHODS() OBJARRAYS CANNOT BE MADE READ-ONLY, even though
       // it is never modified. Otherwise, they will be pre-marked; the
       // GC marking phase will skip them; and by skipping them will fail
       // to mark the methods objects referenced by the array.
     if (obj->is_klass()) {
       mark_object(obj);
       Klass* k = klassOop(obj)->klass_part();
       mark_object(k->java_mirror());
       if (obj->blueprint()->oop_is_instanceKlass()) {
         instanceKlass* ik = (instanceKlass*)k;
         mark_object(ik->methods());
         mark_object(ik->constants());
       }
       if (obj->blueprint()->oop_is_javaArray()) {
         arrayKlass* ak = (arrayKlass*)k;
         mark_object(ak->component_mirror());
       }
       return;
     }
     // Mark constantPool tags and the constantPoolCache.
     else if (obj->is_constantPool()) {
       constantPoolOop pool = constantPoolOop(obj);
       mark_object(pool->cache());
       pool->shared_tags_iterate(&mark_objects);
       return;
     }
     // Mark all method objects.
     if (obj->is_method()) {
       mark_object(obj);
     }
   }
 };
 // Closure:  Mark String objects read-write.
 class MarkStringObjects : public ObjectClosure {
 private:
   MarkObjectsOopClosure mark_objects;
 public:
   void do_object(oop obj) {
     // Mark String objects referenced by constant pool entries.
     if (obj->is_constantPool()) {
       constantPoolOop pool = constantPoolOop(obj);
       pool->shared_strings_iterate(&mark_objects);
       return;
     }
   }
 };
 // Move objects matching specified type (ie. lock_bits) to the specified
 // space.
 class MoveMarkedObjects : public ObjectClosure {
 private:
   OffsetTableContigSpace* _space;
   bool _read_only;
 public:
   MoveMarkedObjects(OffsetTableContigSpace* space, bool read_only) {
     _space = space;
     _read_only = read_only;
   }
   void do_object(oop obj) {
     if (obj->is_shared()) {
       return;
     }
     if (obj->is_gc_marked() && obj->forwardee() == NULL) {
       int s = obj->size();
       oop sh_obj = (oop)_space->allocate(s);
       if (sh_obj == NULL) {
         report_out_of_shared_space(_read_only ? SharedReadOnly : SharedReadWrite);
       }
       if (PrintSharedSpaces && Verbose && WizardMode) {
         tty->print_cr("\nMoveMarkedObjects: " PTR_FORMAT " -> " PTR_FORMAT " %s", obj, sh_obj,
                       (_read_only ? "ro" : "rw"));
       }
       Copy::aligned_disjoint_words((HeapWord*)obj, (HeapWord*)sh_obj, s);
       obj->forward_to(sh_obj);
       if (_read_only) {
         // Readonly objects: set hash value to self pointer and make gc_marked.
         sh_obj->forward_to(sh_obj);
       } else {
         sh_obj->init_mark();
       }
     }
   }
 };
 static void mark_and_move(oop obj, MoveMarkedObjects* move) {
   if (mark_object(obj)) move->do_object(obj);
 }
 enum order_policy {
   OP_favor_startup = 0,
   OP_balanced = 1,
   OP_favor_runtime = 2
 };
 static void mark_and_move_for_policy(order_policy policy, oop obj, MoveMarkedObjects* move) {
   if (SharedOptimizeColdStartPolicy >= policy) mark_and_move(obj, move);
 }
 class MarkAndMoveOrderedReadOnly : public ObjectClosure {
 private:
   MoveMarkedObjects *_move_ro;
 public:
   MarkAndMoveOrderedReadOnly(MoveMarkedObjects *move_ro) : _move_ro(move_ro) {}
   void do_object(oop obj) {
     if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
       instanceKlass* ik = instanceKlass::cast((klassOop)obj);
       int i;
       if (ik->super() != NULL) {
         do_object(ik->super());
       }
       objArrayOop interfaces = ik->local_interfaces();
       mark_and_move_for_policy(OP_favor_startup, interfaces, _move_ro);
       for(i = 0; i < interfaces->length(); i++) {
         klassOop k = klassOop(interfaces->obj_at(i));
         do_object(k);
       }
       objArrayOop methods = ik->methods();
       for(i = 0; i < methods->length(); i++) {
         methodOop m = methodOop(methods->obj_at(i));
         mark_and_move_for_policy(OP_favor_startup, m->constMethod(), _move_ro);
         mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->exception_table(), _move_ro);
         mark_and_move_for_policy(OP_favor_runtime, m->constMethod()->stackmap_data(), _move_ro);
       }
       mark_and_move_for_policy(OP_favor_startup, ik->transitive_interfaces(), _move_ro);
       mark_and_move_for_policy(OP_favor_startup, ik->fields(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(),  _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->method_ordering(),   _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->class_annotations(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->fields_annotations(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->methods_annotations(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->methods_parameter_annotations(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->methods_default_annotations(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->inner_classes(), _move_ro);
       mark_and_move_for_policy(OP_favor_runtime, ik->secondary_supers(), _move_ro);
     }
   }
 };
 class MarkAndMoveOrderedReadWrite: public ObjectClosure {
 private:
   MoveMarkedObjects *_move_rw;
 public:
   MarkAndMoveOrderedReadWrite(MoveMarkedObjects *move_rw) : _move_rw(move_rw) {}
   void do_object(oop obj) {
     if (obj->is_klass() && obj->blueprint()->oop_is_instanceKlass()) {
       instanceKlass* ik = instanceKlass::cast((klassOop)obj);
       int i;
       mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop(), _move_rw);
       if (ik->super() != NULL) {
         do_object(ik->super());
       }
       objArrayOop interfaces = ik->local_interfaces();
       for(i = 0; i < interfaces->length(); i++) {
         klassOop k = klassOop(interfaces->obj_at(i));
         mark_and_move_for_policy(OP_favor_startup, k, _move_rw);
         do_object(k);
       }
       objArrayOop methods = ik->methods();
       mark_and_move_for_policy(OP_favor_startup, methods, _move_rw);
       for(i = 0; i < methods->length(); i++) {
         methodOop m = methodOop(methods->obj_at(i));
         mark_and_move_for_policy(OP_favor_startup, m, _move_rw);
         mark_and_move_for_policy(OP_favor_startup, ik->constants(), _move_rw);          // idempotent
         mark_and_move_for_policy(OP_balanced, ik->constants()->cache(), _move_rw); // idempotent
         mark_and_move_for_policy(OP_balanced, ik->constants()->tags(), _move_rw);  // idempotent
       }
       mark_and_move_for_policy(OP_favor_startup, ik->as_klassOop()->klass(), _move_rw);
       mark_and_move_for_policy(OP_favor_startup, ik->constants()->klass(), _move_rw);
       // Although Java mirrors are marked in MarkReadWriteObjects,
       // apparently they were never moved into shared spaces since
       // MoveMarkedObjects skips marked instance oops.  This may
       // be a bug in the original implementation or simply the vestige
       // of an abandoned experiment.  Nevertheless we leave a hint
       // here in case this capability is ever correctly implemented.
       //
       // mark_and_move_for_policy(OP_favor_runtime, ik->java_mirror(), _move_rw);
     }
   }
 };
 // Adjust references in oops to refer to shared spaces.
 class ResolveForwardingClosure: public OopClosure {
 public:
   void do_oop(oop* p) {
     oop obj = *p;
     if (!obj->is_shared()) {
       if (obj != NULL) {
         oop f = obj->forwardee();
         guarantee(f->is_shared(), "Oop doesn't refer to shared space.");
         *p = f;
       }
     }
   }
   void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
 };
 // The methods array must be reordered by Symbol* address.
 // (See classFileParser.cpp where methods in a class are originally
 // sorted). The addresses of symbols have been changed as a result
 // of moving to the shared space.
 class SortMethodsClosure: public ObjectClosure {
 public:
   void do_object(oop obj) {
     if (obj->blueprint()->oop_is_instanceKlass()) {
       instanceKlass* ik = instanceKlass::cast((klassOop)obj);
       methodOopDesc::sort_methods(ik->methods(),
                                   ik->methods_annotations(),
                                   ik->methods_parameter_annotations(),
                                   ik->methods_default_annotations(),
                                   true /* idempotent, slow */);
     }
   }
 };
 // Itable indices are calculated based on methods array order
 // (see klassItable::compute_itable_index()).  Must reinitialize
 // after ALL methods of ALL classes have been reordered.
 // We assume that since checkconstraints is false, this method
 // cannot throw an exception.  An exception here would be
 // problematic since this is the VMThread, not a JavaThread.
 class ReinitializeItables: public ObjectClosure {
 private:
   Thread* _thread;
 public:
   ReinitializeItables(Thread* thread) : _thread(thread) {}
   void do_object(oop obj) {
     if (obj->blueprint()->oop_is_instanceKlass()) {
       instanceKlass* ik = instanceKlass::cast((klassOop)obj);
       ik->itable()->initialize_itable(false, _thread);
     }
   }
 };
 // Adjust references in oops to refer to shared spaces.
 class PatchOopsClosure: public ObjectClosure {
 private:
   Thread* _thread;
   ResolveForwardingClosure resolve;
 public:
   PatchOopsClosure(Thread* thread) : _thread(thread) {}
   void do_object(oop obj) {
     obj->oop_iterate_header(&resolve);
     obj->oop_iterate(&resolve);
     assert(obj->klass()->is_shared(), "Klass not pointing into shared space.");
     // If the object is a Java object or class which might (in the
     // future) contain a reference to a young gen object, add it to the
     // list.
     if (obj->is_klass() || obj->is_instance()) {
       if (obj->is_klass() ||
           obj->is_a(SystemDictionary::Class_klass()) ||
           obj->is_a(SystemDictionary::Throwable_klass())) {
         // Do nothing
       }
       else if (obj->is_a(SystemDictionary::String_klass())) {
         // immutable objects.
       } else {
         // someone added an object we hadn't accounted for.
         ShouldNotReachHere();
       }
     }
   }
 };
 // Empty the young and old generations.
 class ClearSpaceClosure : public SpaceClosure {
 public:
   void do_space(Space* s) {
     s->clear(SpaceDecorator::Mangle);
   }
 };
 // Closure for serializing initialization data out to a data area to be
 // written to the shared file.
 class WriteClosure : public SerializeOopClosure {
 private:
   oop* top;
   char* end;
   inline void check_space() {
     if ((char*)top + sizeof(oop) > end) {
       report_out_of_shared_space(SharedMiscData);
     }
   }
 public:
   WriteClosure(char* md_top, char* md_end) {
     top = (oop*)md_top;
     end = md_end;
   }
   char* get_top() { return (char*)top; }
   void do_oop(oop* p) {
     check_space();
     oop obj = *p;
     assert(obj->is_oop_or_null(), "invalid oop");
     assert(obj == NULL || obj->is_shared(),
            "Oop in shared space not pointing into shared space.");
     *top = obj;
     ++top;
   }
   void do_oop(narrowOop* pobj) { ShouldNotReachHere(); }
   void do_int(int* p) {
     check_space();
     *top = (oop)(intptr_t)*p;
     ++top;
   }
   void do_size_t(size_t* p) {
     check_space();
     *top = (oop)(intptr_t)*p;
     ++top;
   }
   void do_ptr(void** p) {
     check_space();
     *top = (oop)*p;
     ++top;
   }
   void do_ptr(HeapWord** p) { do_ptr((void **) p); }
   void do_tag(int tag) {
     check_space();
     *top = (oop)(intptr_t)tag;
     ++top;
   }
   void do_region(u_char* start, size_t size) {
     if ((char*)top + size > end) {
       report_out_of_shared_space(SharedMiscData);
     }
     assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
     assert(size % sizeof(oop) == 0, "bad size");
     do_tag((int)size);
     while (size > 0) {
       *top = *(oop*)start;
       ++top;
       start += sizeof(oop);
       size -= sizeof(oop);
     }
   }
   bool reading() const { return false; }
 };
 class ResolveConstantPoolsClosure : public ObjectClosure {
 private:
   TRAPS;
 public:
   ResolveConstantPoolsClosure(Thread *t) {
     __the_thread__ = t;
   }
   void do_object(oop obj) {
     if (obj->is_constantPool()) {
       constantPoolOop cpool = (constantPoolOop)obj;
       int unresolved = cpool->pre_resolve_shared_klasses(THREAD);
     }
   }
 };
 // Print a summary of the contents of the read/write spaces to help
 // identify objects which might be able to be made read-only.  At this
 // point, the objects have been written, and we can trash them as
 // needed.
 static void print_contents() {
   if (PrintSharedSpaces) {
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
     // High level summary of the read-only space:
     ClassifyObjectClosure coc;
     tty->cr(); tty->print_cr("ReadOnly space:");
     gen->ro_space()->object_iterate(&coc);
     coc.print();
     // High level summary of the read-write space:
     coc.reset();
     tty->cr(); tty->print_cr("ReadWrite space:");
     gen->rw_space()->object_iterate(&coc);
     coc.print();
     // Reset counters
     ClearAllocCountClosure cacc;
     gen->ro_space()->object_iterate(&cacc);
     gen->rw_space()->object_iterate(&cacc);
     coc.reset();
     // Lower level summary of the read-only space:
     gen->ro_space()->object_iterate(&coc);
     tty->cr(); tty->print_cr("ReadOnly space:");
     ClassifyInstanceKlassClosure cikc;
     gen->rw_space()->object_iterate(&cikc);
     cikc.print();
     // Reset counters
     gen->ro_space()->object_iterate(&cacc);
     gen->rw_space()->object_iterate(&cacc);
     coc.reset();
     // Lower level summary of the read-write space:
     gen->rw_space()->object_iterate(&coc);
     cikc.reset();
     tty->cr();  tty->print_cr("ReadWrite space:");
     gen->rw_space()->object_iterate(&cikc);
     cikc.print();
   }
 }
 // Patch C++ vtable pointer in klass oops.
 // Klass objects contain references to c++ vtables in the JVM library.
 // Fix them to point to our constructed vtables.  However, don't iterate
 // across the space while doing this, as that causes the vtables to be
 // patched, undoing our useful work.  Instead, iterate to make a list,
 // then use the list to do the fixing.
 //
 // Our constructed vtables:
 // Dump time:
 //  1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs
 //  2. generate_vtable_methods: create jump table, appended to above vtbl_list
 //  3. PatchKlassVtables: for Klass list, patch the vtable entry to point to jump table
 //     rather than to current vtbl
 // Table layout: NOTE FIXED SIZE
 //   1. vtbl pointers
 //   2. #Klass X #virtual methods per Klass
 //   1 entry for each, in the order:
 //   Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry
 //   Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry
 //   ...
 //   Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry,
 //       ... Klass<vtbl_list_size>:method<num_virtuals> entry
 //  Sample entry: (Sparc):
 //   save(sp, -256, sp)
 //   ba,pt common_code
 //   mov XXX, %L0       %L0 gets: Klass index <<8 + method index (note: max method index 255)
 //
 // Restore time:
 //   1. initialize_oops: reserve space for table
 //   2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text
 //
 // Execution time:
 //   First virtual method call for any object of these Klass types:
 //   1. object->klass->klass_part
 //   2. vtable entry for that klass_part points to the jump table entries
 //   3. branches to common_code with %O0/klass_part, %L0: Klass index <<8 + method index
 //   4. common_code:
 //      Get address of new vtbl pointer for this Klass from updated table
 //      Update new vtbl pointer in the Klass: future virtual calls go direct
 //      Jump to method, using new vtbl pointer and method index
 class PatchKlassVtables: public ObjectClosure {
 private:
   GrowableArray<klassOop>* _klass_objects;
 public:
   PatchKlassVtables() {
     _klass_objects = new GrowableArray<klassOop>();
   }
   void do_object(oop obj) {
     if (obj->is_klass()) {
       _klass_objects->append(klassOop(obj));
     }
   }
   void patch(void** vtbl_list, void* new_vtable_start) {
     int n = _klass_objects->length();
     for (int i = 0; i < n; i++) {
       klassOop obj = (klassOop)_klass_objects->at(i);
       Klass* k = obj->klass_part();
       *(void**)k = CompactingPermGenGen::find_matching_vtbl_ptr(
                      vtbl_list, new_vtable_start, k);
     }
   }
 };
 // Walk through all symbols and patch their vtable pointers.
 // Note that symbols have vtable pointers only in non-product builds
 // (see allocation.hpp).
 #ifndef PRODUCT
 class PatchSymbolVtables: public SymbolClosure {
 private:
   void* _new_vtbl_ptr;
 public:
   PatchSymbolVtables(void** vtbl_list, void* new_vtable_start) {
     Symbol s;
     _new_vtbl_ptr = CompactingPermGenGen::find_matching_vtbl_ptr(
                       vtbl_list, new_vtable_start, &s);
   }
   void do_symbol(Symbol** p) {
     Symbol* sym = load_symbol(p);
     *(void**)sym = _new_vtbl_ptr;
   }
 };
 #endif
 // Populate the shared space.
 class VM_PopulateDumpSharedSpace: public VM_Operation {
 private:
   GrowableArray<oop> *_class_promote_order;
   OffsetTableContigSpace* _ro_space;
   OffsetTableContigSpace* _rw_space;
   VirtualSpace* _md_vs;
   VirtualSpace* _mc_vs;
 public:
   VM_PopulateDumpSharedSpace(GrowableArray<oop> *class_promote_order,
                              OffsetTableContigSpace* ro_space,
                              OffsetTableContigSpace* rw_space,
                              VirtualSpace* md_vs, VirtualSpace* mc_vs) {
     _class_promote_order = class_promote_order;
     _ro_space = ro_space;
     _rw_space = rw_space;
     _md_vs = md_vs;
     _mc_vs = mc_vs;
   }
   VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; }
   void doit() {
     Thread* THREAD = VMThread::vm_thread();
     NOT_PRODUCT(SystemDictionary::verify();)
     // The following guarantee is meant to ensure that no loader constraints
     // exist yet, since the constraints table is not shared.  This becomes
     // more important now that we don't re-initialize vtables/itables for
     // shared classes at runtime, where constraints were previously created.
     guarantee(SystemDictionary::constraints()->number_of_entries() == 0,
               "loader constraints are not saved");
     // Revisit and implement this if we prelink method handle call sites:
     guarantee(SystemDictionary::invoke_method_table() == NULL ||
               SystemDictionary::invoke_method_table()->number_of_entries() == 0,
               "invoke method table is not saved");
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     // At this point, many classes have been loaded.
     // Update all the fingerprints in the shared methods.
     tty->print("Calculating fingerprints ... ");
     FingerprintMethodsClosure fpmc;
     gch->object_iterate(&fpmc);
     tty->print_cr("done. ");
     // Remove all references outside the heap.
     tty->print("Removing unshareable information ... ");
     RemoveUnshareableInfoClosure ruic;
     gch->object_iterate(&ruic);
     tty->print_cr("done. ");
     // Move the objects in three passes.
     MarkObjectsOopClosure mark_all;
     MarkCommonReadOnly mark_common_ro;
     MarkStringValues mark_string_values;
     MarkReadWriteObjects mark_rw;
     MarkStringObjects mark_strings;
     MoveMarkedObjects move_ro(_ro_space, true);
     MoveMarkedObjects move_rw(_rw_space, false);
     // The SharedOptimizeColdStart VM option governs the new layout
     // algorithm for promoting classes into the shared archive.
     // The general idea is to minimize cold start time by laying
     // out the objects in the order they are accessed at startup time.
     // By doing this we are trying to eliminate out-of-order accesses
     // in the shared archive.  This benefits cold startup time by making
     // disk reads as sequential as possible during class loading and
     // bootstrapping activities.  There may also be a small secondary
     // effect of better "packing" of more commonly used data on a smaller
     // number of pages, although no direct benefit has been measured from
     // this effect.
     //
     // At the class level of granularity, the promotion order is dictated
     // by the classlist file whose generation is discussed elsewhere.
     //
     // At smaller granularity, optimal ordering was determined by an
     // offline analysis of object access order in the shared archive.
     // The dbx watchpoint facility, combined with SA post-processing,
     // was used to observe common access patterns primarily during
     // classloading.  This information was used to craft the promotion
     // order seen in the following closures.
     //
     // The observed access order is mostly governed by what happens
     // in SystemDictionary::load_shared_class().  NOTE WELL - care
     // should be taken when making changes to this method, because it
     // may invalidate assumptions made about access order!
     //
     // (Ideally, there would be a better way to manage changes to
     //  the access order.  Unfortunately a generic in-VM solution for
     //  dynamically observing access order and optimizing shared
     //  archive layout is pretty difficult.  We go with the static
     //  analysis because the code is fairly mature at this point
     //  and we're betting that the access order won't change much.)
     MarkAndMoveOrderedReadOnly  mark_and_move_ordered_ro(&move_ro);
     MarkAndMoveOrderedReadWrite mark_and_move_ordered_rw(&move_rw);
     // Set up the share data and shared code segments.
     char* md_top = _md_vs->low();
     char* md_end = _md_vs->high();
     char* mc_top = _mc_vs->low();
     char* mc_end = _mc_vs->high();
     // Reserve space for the list of klassOops whose vtables are used
     // for patching others as needed.
     void** vtbl_list = (void**)md_top;
     int vtbl_list_size = CompactingPermGenGen::vtbl_list_size;
     Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
     md_top += vtbl_list_size * sizeof(void*);
     void* vtable = md_top;
     // Reserve space for a new dummy vtable for klass objects in the
     // heap.  Generate self-patching vtable entries.
     CompactingPermGenGen::generate_vtable_methods(vtbl_list,
                                                   &vtable,
                                                   &md_top, md_end,
                                                   &mc_top, mc_end);
     // Reserve space for the total size and the number of stored symbols.
     md_top += sizeof(intptr_t) * 2;
     MoveSymbols move_symbols(md_top, md_end);
     CommonSymbolsClosure traverse_common_symbols(&move_symbols);
     // Phase 1a: remove symbols with _refcount == 0
     SymbolTable::unlink();
     // Phase 1b: move commonly used symbols referenced by oop fields.
     tty->print("Moving common symbols to metadata section at " PTR_FORMAT " ... ",
                move_symbols.get_top());
     gch->object_iterate(&traverse_common_symbols);
     tty->print_cr("done. ");
     // Phase 1c: move known names and signatures.
     tty->print("Moving vmSymbols to metadata section at " PTR_FORMAT " ... ",
                move_symbols.get_top());
     vmSymbols::symbols_do(&move_symbols);
     tty->print_cr("done. ");
     // Phase 1d: move the remaining symbols by scanning the whole SymbolTable.
     void* extra_symbols = move_symbols.get_top();
     tty->print("Moving the remaining symbols to metadata section at " PTR_FORMAT " ... ",
                move_symbols.get_top());
     SymbolTable::symbols_do(&move_symbols);
     tty->print_cr("done. ");
     // Record the total length of all symbols at the beginning of the block.
     ((intptr_t*)md_top)[-2] = move_symbols.get_top() - md_top;
     ((intptr_t*)md_top)[-1] = move_symbols.count();
     tty->print_cr("Moved %d symbols, %d bytes.",
                   move_symbols.count(), move_symbols.get_top() - md_top);
     // Advance the pointer to the end of symbol store.
     md_top = move_symbols.get_top();
     // Phase 2: move commonly used read-only objects to the read-only space.
     if (SharedOptimizeColdStart) {
       tty->print("Moving pre-ordered read-only objects to shared space at " PTR_FORMAT " ... ",
                  _ro_space->top());
       for (int i = 0; i < _class_promote_order->length(); i++) {
         oop obj = _class_promote_order->at(i);
         mark_and_move_ordered_ro.do_object(obj);
       }
       tty->print_cr("done. ");
     }
     tty->print("Moving read-only objects to shared space at " PTR_FORMAT " ... ",
                _ro_space->top());
     gch->object_iterate(&mark_common_ro);
     gch->object_iterate(&move_ro);
     tty->print_cr("done. ");
     // Phase 3: move String character arrays to the read-only space.
     tty->print("Moving string char arrays to shared space at " PTR_FORMAT " ... ",
                _ro_space->top());
     gch->object_iterate(&mark_string_values);
     gch->object_iterate(&move_ro);
     tty->print_cr("done. ");
     // Phase 4: move read-write objects to the read-write space, except
     // Strings.
     if (SharedOptimizeColdStart) {
       tty->print("Moving pre-ordered read-write objects to shared space at " PTR_FORMAT " ... ",
                  _rw_space->top());
       for (int i = 0; i < _class_promote_order->length(); i++) {
         oop obj = _class_promote_order->at(i);
         mark_and_move_ordered_rw.do_object(obj);
       }
       tty->print_cr("done. ");
     }
     tty->print("Moving read-write objects to shared space at " PTR_FORMAT " ... ",
                _rw_space->top());
     Universe::oops_do(&mark_all, true);
     SystemDictionary::oops_do(&mark_all);
     oop tmp = Universe::arithmetic_exception_instance();
     mark_object(java_lang_Throwable::message(tmp));
     gch->object_iterate(&mark_rw);
     gch->object_iterate(&move_rw);
     tty->print_cr("done. ");
     // Phase 5: move String objects to the read-write space.
     tty->print("Moving String objects to shared space at " PTR_FORMAT " ... ",
                _rw_space->top());
     StringTable::oops_do(&mark_all);
     gch->object_iterate(&mark_strings);
     gch->object_iterate(&move_rw);
     tty->print_cr("done. ");
     tty->print_cr("Read-write space ends at " PTR_FORMAT ", %d bytes.",
                   _rw_space->top(), _rw_space->used());
 #ifdef DEBUG
     // Check: scan for objects which were not moved.
     CheckRemainingObjects check_objects;
     gch->object_iterate(&check_objects);
     check_objects.status();
 #endif
     // Resolve forwarding in objects and saved C++ structures
     tty->print("Updating references to shared objects ... ");
     ResolveForwardingClosure resolve;
     Universe::oops_do(&resolve);
     SystemDictionary::oops_do(&resolve);
     StringTable::oops_do(&resolve);
     // Fix (forward) all of the references in these shared objects (which
     // are required to point ONLY to objects in the shared spaces).
     // Also, create a list of all objects which might later contain a
     // reference to a younger generation object.
     CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
     PatchOopsClosure patch(THREAD);
     gen->ro_space()->object_iterate(&patch);
     gen->rw_space()->object_iterate(&patch);
     // Previously method sorting was done concurrently with forwarding
     // pointer resolution in the shared spaces.  This imposed an ordering
     // restriction in that methods were required to be promoted/patched
     // before their holder classes.  (Because constant pool pointers in
     // methodKlasses are required to be resolved before their holder class
     // is visited for sorting, otherwise methods are sorted by incorrect,
     // pre-forwarding addresses.)
     //
     // Now, we reorder methods as a separate step after ALL forwarding
     // pointer resolution, so that methods can be promoted in any order
     // with respect to their holder classes.
     SortMethodsClosure sort;
     gen->ro_space()->object_iterate(&sort);
     gen->rw_space()->object_iterate(&sort);
     ReinitializeItables reinit_itables(THREAD);
     gen->ro_space()->object_iterate(&reinit_itables);
     gen->rw_space()->object_iterate(&reinit_itables);
     tty->print_cr("done. ");
     tty->cr();
     // Reorder the system dictionary.  (Moving the symbols opps affects
     // how the hash table indices are calculated.)
     SystemDictionary::reorder_dictionary();
     // Empty the non-shared heap (because most of the objects were
     // copied out, and the remainder cannot be considered valid oops).
     ClearSpaceClosure csc;
     for (int i = 0; i < gch->n_gens(); ++i) {
       gch->get_gen(i)->space_iterate(&csc);
     }
     csc.do_space(gen->the_space());
     NOT_PRODUCT(SystemDictionary::verify();)
     // Copy the String table, the symbol table, and the system
     // dictionary to the shared space in usable form.  Copy the hastable
     // buckets first [read-write], then copy the linked lists of entries
     // [read-only].
     SymbolTable::reverse(extra_symbols);
     NOT_PRODUCT(SymbolTable::verify());
     SymbolTable::copy_buckets(&md_top, md_end);
     StringTable::reverse();
     NOT_PRODUCT(StringTable::verify());
     StringTable::copy_buckets(&md_top, md_end);
     SystemDictionary::reverse();
     SystemDictionary::copy_buckets(&md_top, md_end);
     ClassLoader::verify();
     ClassLoader::copy_package_info_buckets(&md_top, md_end);
     ClassLoader::verify();
     SymbolTable::copy_table(&md_top, md_end);
     StringTable::copy_table(&md_top, md_end);
     SystemDictionary::copy_table(&md_top, md_end);
     ClassLoader::verify();
     ClassLoader::copy_package_info_table(&md_top, md_end);
     ClassLoader::verify();
     // Print debug data.
     if (PrintSharedSpaces) {
       const char* fmt = "%s space: " PTR_FORMAT " out of " PTR_FORMAT " bytes allocated at " PTR_FORMAT ".";
       tty->print_cr(fmt, "ro", _ro_space->used(), _ro_space->capacity(),
                     _ro_space->bottom());
       tty->print_cr(fmt, "rw", _rw_space->used(), _rw_space->capacity(),
                     _rw_space->bottom());
     }
     // Write the oop data to the output array.
     WriteClosure wc(md_top, md_end);
     CompactingPermGenGen::serialize_oops(&wc);
     md_top = wc.get_top();
     // Update the vtable pointers in all of the Klass objects in the
     // heap. They should point to newly generated vtable.
     PatchKlassVtables pkvt;
     _rw_space->object_iterate(&pkvt);
     pkvt.patch(vtbl_list, vtable);
 #ifndef PRODUCT
     // Update the vtable pointers in all symbols,
     // but only in non-product builds where symbols DO have virtual methods.
     PatchSymbolVtables psvt(vtbl_list, vtable);
     SymbolTable::symbols_do(&psvt);
 #endif
     char* saved_vtbl = (char*)malloc(vtbl_list_size * sizeof(void*));
     memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*));
     memset(vtbl_list, 0, vtbl_list_size * sizeof(void*));
     // Create and write the archive file that maps the shared spaces.
     FileMapInfo* mapinfo = new FileMapInfo();
     mapinfo->populate_header(gch->gen_policy()->max_alignment());
     // Pass 1 - update file offsets in header.
     mapinfo->write_header();
     mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
     _ro_space->set_saved_mark();
     mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
     _rw_space->set_saved_mark();
     mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
                           pointer_delta(md_top, _md_vs->low(), sizeof(char)),
                           SharedMiscDataSize,
                           false, false);
     mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
                           pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
                           SharedMiscCodeSize,
                           true, true);
     // Pass 2 - write data.
     mapinfo->open_for_write();
     mapinfo->write_header();
     mapinfo->write_space(CompactingPermGenGen::ro, _ro_space, true);
     mapinfo->write_space(CompactingPermGenGen::rw, _rw_space, false);
     mapinfo->write_region(CompactingPermGenGen::md, _md_vs->low(),
                           pointer_delta(md_top, _md_vs->low(), sizeof(char)),
                           SharedMiscDataSize,
                           false, false);
     mapinfo->write_region(CompactingPermGenGen::mc, _mc_vs->low(),
                           pointer_delta(mc_top, _mc_vs->low(), sizeof(char)),
                           SharedMiscCodeSize,
                           true, true);
     mapinfo->close();
     // Summarize heap.
     memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*));
     print_contents();
   }
 }; // class VM_PopulateDumpSharedSpace
 // Populate the shared spaces and dump to a file.
 jint CompactingPermGenGen::dump_shared(GrowableArray<oop>* class_promote_order, TRAPS) {
   GenCollectedHeap* gch = GenCollectedHeap::heap();
   // Calculate hash values for all of the (interned) strings to avoid
   // writes to shared pages in the future.
   tty->print("Calculating hash values for String objects .. ");
   StringHashCodeClosure shcc(THREAD);
   StringTable::oops_do(&shcc);
   tty->print_cr("done. ");
   CompactingPermGenGen* gen = (CompactingPermGenGen*)gch->perm_gen();
   VM_PopulateDumpSharedSpace op(class_promote_order,
                                 gen->ro_space(), gen->rw_space(),
                                 gen->md_space(), gen->mc_space());
   VMThread::execute(&op);
   return JNI_OK;
 }
 void* CompactingPermGenGen::find_matching_vtbl_ptr(void** vtbl_list,
                                                    void* new_vtable_start,
                                                    void* obj) {
   void* old_vtbl_ptr = *(void**)obj;
   for (int i = 0; i < vtbl_list_size; i++) {
     if (vtbl_list[i] == old_vtbl_ptr) {
       return (void**)new_vtable_start + i * num_virtuals;
     }
   }
   ShouldNotReachHere();
   return NULL;
 }
 class LinkClassesClosure : public ObjectClosure {
  private:
   Thread* THREAD;
  public:
   LinkClassesClosure(Thread* thread) : THREAD(thread) {}
   void do_object(oop obj) {
     if (obj->is_klass()) {
       Klass* k = Klass::cast((klassOop) obj);
       if (k->oop_is_instance()) {
         instanceKlass* ik = (instanceKlass*) k;
         // Link the class to cause the bytecodes to be rewritten and the
         // cpcache to be created.
         if (ik->get_init_state() < instanceKlass::linked) {
           ik->link_class(THREAD);
           guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting");
         }
         // Create String objects from string initializer symbols.
         ik->constants()->resolve_string_constants(THREAD);
         guarantee(!HAS_PENDING_EXCEPTION, "exception resolving string constants");
       }
     }
   }
 };
 // Support for a simple checksum of the contents of the class list
 // file to prevent trivial tampering. The algorithm matches that in
 // the MakeClassList program used by the J2SE build process.
 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe))
 static jlong
 jsum(jlong start, const char *buf, const int len)
 {
     jlong h = start;
     char *p = (char *)buf, *e = p + len;
     while (p < e) {
         char c = *p++;
         if (c <= ' ') {
             /* Skip spaces and control characters */
             continue;
         }
         h = 31 * h + c;
     }
     return h;
 }
 // Preload classes from a list, populate the shared spaces and dump to a
 // file.
 void GenCollectedHeap::preload_and_dump(TRAPS) {
   TraceTime timer("Dump Shared Spaces", TraceStartupTime);
   ResourceMark rm;
   // Preload classes to be shared.
   // Should use some os:: method rather than fopen() here. aB.
   // Construct the path to the class list (in jre/lib)
   // Walk up two directories from the location of the VM and
   // optionally tack on "lib" (depending on platform)
   char class_list_path[JVM_MAXPATHLEN];
   os::jvm_path(class_list_path, sizeof(class_list_path));
   for (int i = 0; i < 3; i++) {
     char *end = strrchr(class_list_path, *os::file_separator());
     if (end != NULL) *end = '\0';
   }
   int class_list_path_len = (int)strlen(class_list_path);
   if (class_list_path_len >= 3) {
     if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) {
       strcat(class_list_path, os::file_separator());
       strcat(class_list_path, "lib");
     }
   }
   strcat(class_list_path, os::file_separator());
   strcat(class_list_path, "classlist");
   FILE* file = fopen(class_list_path, "r");
   if (file != NULL) {
     jlong computed_jsum  = JSUM_SEED;
     jlong file_jsum      = 0;
     char class_name[256];
     int class_count = 0;
     GenCollectedHeap* gch = GenCollectedHeap::heap();
     gch->_preloading_shared_classes = true;
     GrowableArray<oop>* class_promote_order = new GrowableArray<oop>();
     // Preload (and intern) strings which will be used later.
     StringTable::intern("main", THREAD);
     StringTable::intern("([Ljava/lang/String;)V", THREAD);
     StringTable::intern("Ljava/lang/Class;", THREAD);
     StringTable::intern("I", THREAD);   // Needed for StringBuffer persistence?
     StringTable::intern("Z", THREAD);   // Needed for StringBuffer persistence?
     // sun.io.Converters
     static const char obj_array_sig[] = "[[Ljava/lang/Object;";
     SymbolTable::lookup(obj_array_sig, (int)strlen(obj_array_sig), THREAD);
     // java.util.HashMap
     static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;";
     SymbolTable::lookup(map_entry_array_sig, (int)strlen(map_entry_array_sig),
                         THREAD);
     tty->print("Loading classes to share ... ");
     while ((fgets(class_name, sizeof class_name, file)) != NULL) {
       if (*class_name == '#') {
         jint fsh, fsl;
         if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) {
           file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff);
         }
         continue;
       }
       // Remove trailing newline
       size_t name_len = strlen(class_name);
       class_name[name_len-1] = '\0';
       computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1);
       // Got a class name - load it.
       TempNewSymbol class_name_symbol = SymbolTable::new_symbol(class_name, THREAD);
       guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol.");
       klassOop klass = SystemDictionary::resolve_or_null(class_name_symbol,
                                                          THREAD);
       guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class.");
       if (klass != NULL) {
         if (PrintSharedSpaces) {
           tty->print_cr("Shared spaces preloaded: %s", class_name);
         }
         instanceKlass* ik = instanceKlass::cast(klass);
         // Should be class load order as per -XX:+TraceClassLoadingPreorder
         class_promote_order->append(ik->as_klassOop());
         // Link the class to cause the bytecodes to be rewritten and the
         // cpcache to be created. The linking is done as soon as classes
         // are loaded in order that the related data structures (klass,
         // cpCache, Sting constants) are located together.
         if (ik->get_init_state() < instanceKlass::linked) {
           ik->link_class(THREAD);
           guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting");
         }
         // Create String objects from string initializer symbols.
         ik->constants()->resolve_string_constants(THREAD);
         class_count++;
       } else {
         if (PrintSharedSpaces) {
           tty->cr();
           tty->print_cr(" Preload failed: %s", class_name);
         }
       }
       file_jsum = 0; // Checksum must be on last line of file
     }
     if (computed_jsum != file_jsum) {
       tty->cr();
       tty->print_cr("Preload failed: checksum of class list was incorrect.");
       exit(1);
     }
     tty->print_cr("done. ");
     if (PrintSharedSpaces) {
       tty->print_cr("Shared spaces: preloaded %d classes", class_count);
     }
     // Rewrite and unlink classes.
     tty->print("Rewriting and unlinking classes ... ");
     // Make heap parsable
     ensure_parsability(false); // arg is actually don't care
     // Link any classes which got missed.  (It's not quite clear why
     // they got missed.)  This iteration would be unsafe if we weren't
     // single-threaded at this point; however we can't do it on the VM
     // thread because it requires object allocation.
     LinkClassesClosure lcc(Thread::current());
     object_iterate(&lcc);
     ensure_parsability(false); // arg is actually don't care
     tty->print_cr("done. ");
     // Create and dump the shared spaces.
     jint err = CompactingPermGenGen::dump_shared(class_promote_order, THREAD);
     if (err != JNI_OK) {
       fatal("Dumping shared spaces failed.");
     }
   } else {
     char errmsg[JVM_MAXPATHLEN];
     os::lasterror(errmsg, JVM_MAXPATHLEN);
     tty->print_cr("Loading classlist failed: %s", errmsg);
     exit(1);
   }
   // Since various initialization steps have been undone by this process,
   // it is not reasonable to continue running a java process.
   exit(0);
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/dump.cpp@b099aaf51bf8 (annotated)

src/share/vm/memory/dump.cpp