8251261: CDS dumping should not clear states in live classes

Reviewed-by: minqi, ccheung

src/hotspot/share/classfile/javaClasses.cpp

@@ -1179,8 +1179,7 @@ oop java_lang_Class::archive_mirror(Klass* k, TRAPS) {
     if (!(ik->is_shared_boot_class() || ik->is_shared_platform_class() ||
           ik->is_shared_app_class())) {
       // Archiving mirror for classes from non-builtin loaders is not
-      // supported. Clear the _java_mirror within the archived class.
-      k->clear_java_mirror_handle();
+      // supported.
       return NULL;
     }
   }

src/hotspot/share/memory/archiveBuilder.cpp

@@ -41,6 +41,7 @@
 #include "utilities/hashtable.inline.hpp"
 
 ArchiveBuilder* ArchiveBuilder::_singleton = NULL;
+intx ArchiveBuilder::_buffer_to_target_delta = 0;
 
 ArchiveBuilder::OtherROAllocMark::~OtherROAllocMark() {
   char* newtop = ArchiveBuilder::singleton()->_ro_region->top();
@@ -564,6 +565,34 @@ void ArchiveBuilder::relocate_well_known_klasses() {
   SystemDictionary::well_known_klasses_do(&doit);
 }
 
+void ArchiveBuilder::make_klasses_shareable() {
+  for (int i = 0; i < klasses()->length(); i++) {
+    Klass* k = klasses()->at(i);
+    k->remove_java_mirror();
+    if (k->is_objArray_klass()) {
+      // InstanceKlass and TypeArrayKlass will in turn call remove_unshareable_info
+      // on their array classes.
+    } else if (k->is_typeArray_klass()) {
+      k->remove_unshareable_info();
+    } else {
+      assert(k->is_instance_klass(), " must be");
+      InstanceKlass* ik = InstanceKlass::cast(k);
+      if (DynamicDumpSharedSpaces) {
+        // For static dump, class loader type are already set.
+        ik->assign_class_loader_type();
+      }
+
+      MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread::current(), ik);
+      ik->remove_unshareable_info();
+
+      if (log_is_enabled(Debug, cds, class)) {
+        ResourceMark rm;
+        log_debug(cds, class)("klasses[%4d] = " PTR_FORMAT " %s", i, p2i(to_target(ik)), ik->external_name());
+      }
+    }
+  }
+}
+
 void ArchiveBuilder::print_stats(int ro_all, int rw_all, int mc_all) {
   _alloc_stats->print_stats(ro_all, rw_all, mc_all);
 }

src/hotspot/share/memory/archiveBuilder.hpp

@@ -193,6 +193,37 @@ protected:
     _ro_region = ro_region;
   }
 
+protected:
+  DumpRegion* _current_dump_space;
+  address _alloc_bottom;
+
+  DumpRegion* current_dump_space() const {  return _current_dump_space;  }
+
+public:
+  void set_current_dump_space(DumpRegion* r) { _current_dump_space = r; }
+
+  bool is_in_buffer_space(address p) const {
+    return (_alloc_bottom <= p && p < (address)current_dump_space()->top());
+  }
+
+  template <typename T> bool is_in_target_space(T target_obj) const {
+    address buff_obj = address(target_obj) - _buffer_to_target_delta;
+    return is_in_buffer_space(buff_obj);
+  }
+
+  template <typename T> bool is_in_buffer_space(T obj) const {
+    return is_in_buffer_space(address(obj));
+  }
+
+  template <typename T> T to_target_no_check(T obj) const {
+    return (T)(address(obj) + _buffer_to_target_delta);
+  }
+
+  template <typename T> T to_target(T obj) const {
+    assert(is_in_buffer_space(obj), "must be");
+    return (T)(address(obj) + _buffer_to_target_delta);
+  }
+
 public:
   ArchiveBuilder(DumpRegion* rw_region, DumpRegion* ro_region);
   ~ArchiveBuilder();
@@ -208,7 +239,7 @@ public:
   void dump_ro_region();
   void relocate_pointers();
   void relocate_well_known_klasses();
-
+  void make_klasses_shareable();
   address get_dumped_addr(address src_obj) const;
 
   // All klasses and symbols that will be copied into the archive
@@ -235,6 +266,7 @@ public:
   }
 
   void print_stats(int ro_all, int rw_all, int mc_all);
+  static intx _buffer_to_target_delta;
 };
 
 #endif // SHARE_MEMORY_ARCHIVEBUILDER_HPP

src/hotspot/share/memory/dynamicArchive.cpp

@@ -44,8 +44,6 @@
 
 class DynamicArchiveBuilder : public ArchiveBuilder {
 public:
-  static intx _buffer_to_target_delta;
-  DumpRegion* _current_dump_space;
 
   static size_t reserve_alignment() {
     return os::vm_allocation_granularity();
@@ -59,32 +57,6 @@ public:
     ArchivePtrMarker::mark_pointer(ptr_loc);
   }
 
-  DumpRegion* current_dump_space() const {
-    return _current_dump_space;
-  }
-
-  bool is_in_buffer_space(address p) const {
-    return (_alloc_bottom <= p && p < (address)current_dump_space()->top());
-  }
-
-  template <typename T> bool is_in_target_space(T target_obj) const {
-    address buff_obj = address(target_obj) - _buffer_to_target_delta;
-    return is_in_buffer_space(buff_obj);
-  }
-
-  template <typename T> bool is_in_buffer_space(T obj) const {
-    return is_in_buffer_space(address(obj));
-  }
-
-  template <typename T> T to_target_no_check(T obj) const {
-    return (T)(address(obj) + _buffer_to_target_delta);
-  }
-
-  template <typename T> T to_target(T obj) const {
-    assert(is_in_buffer_space(obj), "must be");
-    return (T)(address(obj) + _buffer_to_target_delta);
-  }
-
   template <typename T> T get_dumped_addr(T obj) {
     return (T)ArchiveBuilder::get_dumped_addr((address)obj);
   }
@@ -113,7 +85,6 @@ public:
 
 public:
   DynamicArchiveHeader *_header;
-  address _alloc_bottom;
   address _last_verified_top;
   size_t _other_region_used_bytes;
 
@@ -128,7 +99,7 @@ public:
   void init_header(address addr);
   void release_header();
   void make_trampolines();
-  void make_klasses_shareable();
+  void sort_methods();
   void sort_methods(InstanceKlass* ik) const;
   void remark_pointers_for_instance_klass(InstanceKlass* k, bool should_mark) const;
   void relocate_buffer_to_target();
@@ -250,6 +221,7 @@ public:
     verify_estimate_size(_estimated_hashtable_bytes, "Hashtables");
 
     make_trampolines();
+    sort_methods();
 
     log_info(cds)("Make classes shareable");
     make_klasses_shareable();
@@ -275,8 +247,6 @@ public:
   }
 };
 
-intx DynamicArchiveBuilder::_buffer_to_target_delta;
-
 size_t DynamicArchiveBuilder::estimate_archive_size() {
   // size of the symbol table and two dictionaries, plus the RunTimeSharedClassInfo's
   _estimated_hashtable_bytes = 0;
@@ -408,35 +378,14 @@ void DynamicArchiveBuilder::make_trampolines() {
   guarantee(p <= mc_space->top(), "Estimate of trampoline size is insufficient");
 }
 
-void DynamicArchiveBuilder::make_klasses_shareable() {
-  int i, count = klasses()->length();
-
+void DynamicArchiveBuilder::sort_methods() {
   InstanceKlass::disable_method_binary_search();
-  for (i = 0; i < count; i++) {
+  for (int i = 0; i < klasses()->length(); i++) {
     Klass* k = klasses()->at(i);
     if (k->is_instance_klass()) {
       sort_methods(InstanceKlass::cast(k));
     }
   }
-
-  for (i = 0; i < count; i++) {
-    Klass* k = klasses()->at(i);
-    if (!k->is_instance_klass()) {
-      continue;
-    }
-    InstanceKlass* ik = InstanceKlass::cast(k);
-    ik->assign_class_loader_type();
-
-    MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread::current(), ik);
-    ik->remove_unshareable_info();
-
-    assert(ik->array_klasses() == NULL, "sanity");
-
-    if (log_is_enabled(Debug, cds, dynamic)) {
-      ResourceMark rm;
-      log_debug(cds, dynamic)("klasses[%4i] = " PTR_FORMAT " %s", i, p2i(to_target(ik)), ik->external_name());
-    }
-  }
 }
 
 // The address order of the copied Symbols may be different than when the original

src/hotspot/share/memory/heapShared.cpp

@@ -36,6 +36,7 @@
 #include "logging/log.hpp"
 #include "logging/logMessage.hpp"
 #include "logging/logStream.hpp"
+#include "memory/archiveBuilder.hpp"
 #include "memory/archiveUtils.hpp"
 #include "memory/filemap.hpp"
 #include "memory/heapShared.inline.hpp"
@@ -398,7 +399,7 @@ void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k, Klass *relocate
       new(ResourceObj::C_HEAP, mtClass) GrowableArray<Klass*>(50, mtClass);
   }
 
-  assert(relocated_k->is_shared(), "must be a shared class");
+  assert(ArchiveBuilder::singleton()->is_in_buffer_space(relocated_k), "must be a shared class");
 
   if (_k == relocated_k) {
     // Don't add the Klass containing the sub-graph to it's own klass

src/hotspot/share/memory/metaspaceShared.cpp

@@ -544,30 +544,6 @@ GrowableArray<Klass*>* MetaspaceShared::collected_klasses() {
   return _global_klass_objects;
 }
 
-static void remove_unshareable_in_classes() {
-  for (int i = 0; i < _global_klass_objects->length(); i++) {
-    Klass* k = _global_klass_objects->at(i);
-    if (!k->is_objArray_klass()) {
-      // InstanceKlass and TypeArrayKlass will in turn call remove_unshareable_info
-      // on their array classes.
-      assert(k->is_instance_klass() || k->is_typeArray_klass(), "must be");
-      k->remove_unshareable_info();
-    }
-  }
-}
-
-static void remove_java_mirror_in_classes() {
-  for (int i = 0; i < _global_klass_objects->length(); i++) {
-    Klass* k = _global_klass_objects->at(i);
-    if (!k->is_objArray_klass()) {
-      // InstanceKlass and TypeArrayKlass will in turn call remove_unshareable_info
-      // on their array classes.
-      assert(k->is_instance_klass() || k->is_typeArray_klass(), "must be");
-      k->remove_java_mirror();
-    }
-  }
-}
-
 static void rewrite_nofast_bytecode(const methodHandle& method) {
   BytecodeStream bcs(method);
   while (!bcs.is_last_bytecode()) {
@@ -587,21 +563,9 @@ static void rewrite_nofast_bytecode(const methodHandle& method) {
   }
 }
 
-// Walk all methods in the class list to ensure that they won't be modified at
-// run time. This includes:
 // [1] Rewrite all bytecodes as needed, so that the ConstMethod* will not be modified
 //     at run time by RewriteBytecodes/RewriteFrequentPairs
 // [2] Assign a fingerprint, so one doesn't need to be assigned at run-time.
-static void rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread* thread) {
-  for (int i = 0; i < _global_klass_objects->length(); i++) {
-    Klass* k = _global_klass_objects->at(i);
-    if (k->is_instance_klass()) {
-      InstanceKlass* ik = InstanceKlass::cast(k);
-      MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(thread, ik);
-    }
-  }
-}
-
 void MetaspaceShared::rewrite_nofast_bytecodes_and_calculate_fingerprints(Thread* thread, InstanceKlass* ik) {
   for (int i = 0; i < ik->methods()->length(); i++) {
     methodHandle m(thread, ik->methods()->at(i));
@@ -645,7 +609,10 @@ public:
 class StaticArchiveBuilder : public ArchiveBuilder {
 public:
   StaticArchiveBuilder(DumpRegion* rw_region, DumpRegion* ro_region)
-    : ArchiveBuilder(rw_region, ro_region) {}
+    : ArchiveBuilder(rw_region, ro_region) {
+    _alloc_bottom = address(SharedBaseAddress);
+    _buffer_to_target_delta = 0;
+  }
 
   virtual void iterate_roots(MetaspaceClosure* it, bool is_relocating_pointers) {
     FileMapInfo::metaspace_pointers_do(it, false);
@@ -669,13 +636,6 @@ public:
 char* VM_PopulateDumpSharedSpace::dump_read_only_tables() {
   ArchiveBuilder::OtherROAllocMark mark;
 
-  log_info(cds)("Removing java_mirror ... ");
-  if (!HeapShared::is_heap_object_archiving_allowed()) {
-    Universe::clear_basic_type_mirrors();
-  }
-  remove_java_mirror_in_classes();
-  log_info(cds)("done. ");
-
   SystemDictionaryShared::write_to_archive();
 
   // Write the other data to the output array.
@@ -765,19 +725,10 @@ void VM_PopulateDumpSharedSpace::doit() {
   SystemDictionaryShared::check_excluded_classes();
 
   StaticArchiveBuilder builder(&_rw_region, &_ro_region);
+  builder.set_current_dump_space(&_mc_region);
   builder.gather_klasses_and_symbols();
   _global_klass_objects = builder.klasses();
 
-  // Ensure the ConstMethods won't be modified at run-time
-  log_info(cds)("Updating ConstMethods ... ");
-  rewrite_nofast_bytecodes_and_calculate_fingerprints(THREAD);
-  log_info(cds)("done. ");
-
-  // Remove all references outside the metadata
-  log_info(cds)("Removing unshareable information ... ");
-  remove_unshareable_in_classes();
-  log_info(cds)("done. ");
-
   builder.gather_source_objs();
 
   CppVtables::allocate_cloned_cpp_vtptrs();
@@ -786,6 +737,7 @@ void VM_PopulateDumpSharedSpace::doit() {
 
   {
     _mc_region.pack(&_rw_region);
+    builder.set_current_dump_space(&_rw_region);
     builder.dump_rw_region();
 #if INCLUDE_CDS_JAVA_HEAP
     if (MetaspaceShared::use_full_module_graph()) {
@@ -798,6 +750,7 @@ void VM_PopulateDumpSharedSpace::doit() {
   }
   {
     _rw_region.pack(&_ro_region);
+    builder.set_current_dump_space(&_ro_region);
     builder.dump_ro_region();
 #if INCLUDE_CDS_JAVA_HEAP
     if (MetaspaceShared::use_full_module_graph()) {
@@ -818,6 +771,9 @@ void VM_PopulateDumpSharedSpace::doit() {
 
   builder.relocate_well_known_klasses();
 
+  log_info(cds)("Make classes shareable");
+  builder.make_klasses_shareable();
+
   char* serialized_data = dump_read_only_tables();
   _ro_region.pack();
 
@@ -871,9 +827,9 @@ void VM_PopulateDumpSharedSpace::doit() {
             "for testing purposes only and should not be used in a production environment");
   }
 
-  // There may be other pending VM operations that operate on the InstanceKlasses,
-  // which will fail because InstanceKlasses::remove_unshareable_info()
-  // has been called. Forget these operations and exit the VM directly.
+  // There may be pending VM operations. We have changed some global states
+  // (such as SystemDictionary::_well_known_klasses) that may cause these VM operations
+  // to fail. For safety, forget these operations and exit the VM directly.
   vm_direct_exit(0);
 }
 

src/hotspot/share/memory/universe.cpp

@@ -185,15 +185,6 @@ void Universe::replace_mirror(BasicType t, oop new_mirror) {
   Universe::_mirrors[t].replace(new_mirror);
 }
 
-// Not sure why CDS has to do this
-void Universe::clear_basic_type_mirrors() {
-  for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
-    if (!is_reference_type((BasicType)i)) {
-      Universe::_mirrors[i].replace(NULL);
-    }
-  }
-}
-
 void Universe::basic_type_classes_do(void f(Klass*)) {
   for (int i = T_BOOLEAN; i < T_LONG+1; i++) {
     f(_typeArrayKlassObjs[i]);
@@ -245,7 +236,11 @@ void Universe::serialize(SerializeClosure* f) {
           _mirrors[i] = OopHandle(vm_global(), mirror_oop);
         }
       } else {
-        mirror_oop = _mirrors[i].resolve();
+        if (HeapShared::is_heap_object_archiving_allowed()) {
+          mirror_oop = _mirrors[i].resolve();
+        } else {
+          mirror_oop = NULL;
+        }
         f->do_oop(&mirror_oop); // write to archive
       }
       if (mirror_oop != NULL) { // may be null if archived heap is disabled

src/hotspot/share/memory/universe.hpp

@@ -232,7 +232,6 @@ class Universe: AllStatic {
 
   static oop java_mirror(BasicType t);
   static void replace_mirror(BasicType t, oop obj);
-  static void clear_basic_type_mirrors();
 
   static oop      main_thread_group();
   static void set_main_thread_group(oop group);

src/hotspot/share/oops/constantPool.cpp

@@ -283,7 +283,6 @@ void ConstantPool::archive_resolved_references(Thread* THREAD) {
         ik->is_shared_app_class())) {
     // Archiving resolved references for classes from non-builtin loaders
     // is not yet supported.
-    set_resolved_references(OopHandle());
     return;
   }
 
@@ -316,7 +315,6 @@ void ConstantPool::archive_resolved_references(Thread* THREAD) {
     // resolved references will be created using the normal process
     // when there is no archived value.
     _cache->set_archived_references(archived);
-    set_resolved_references(OopHandle());
   }
 }
 
@@ -396,15 +394,7 @@ void ConstantPool::remove_unshareable_info() {
   // at runtime.
   set_resolved_reference_length(
     resolved_references() != NULL ? resolved_references()->length() : 0);
-
-  // If archiving heap objects is not allowed, clear the resolved references.
-  // Otherwise, it is cleared after the resolved references array is cached
-  // (see archive_resolved_references()).
-  // If DynamicDumpSharedSpaces is enabled, clear the resolved references also
-  // as java objects are not archived in the top layer.
-  if (!HeapShared::is_heap_object_archiving_allowed() || DynamicDumpSharedSpaces) {
-    set_resolved_references(OopHandle());
-  }
+  set_resolved_references(OopHandle());
 
   // Shared ConstantPools are in the RO region, so the _flags cannot be modified.
   // The _on_stack flag is used to prevent ConstantPools from deallocation during