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 /*

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  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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  * 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

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 #ifndef SHARE_VM_OOPS_KLASSVTABLE_HPP

 #define SHARE_VM_OOPS_KLASSVTABLE_HPP

 #include "memory/allocation.hpp"

 #include "oops/oopsHierarchy.hpp"

 #include "runtime/handles.hpp"

 #include "utilities/growableArray.hpp"

 // A klassVtable abstracts the variable-length vtable that is embedded in instanceKlass

 // and arrayKlass.  klassVtable objects are used just as convenient transient accessors to the vtable,

 // not to actually hold the vtable data.

 // Note: the klassVtable should not be accessed before the class has been verified

 // (until that point, the vtable is uninitialized).

 // Currently a klassVtable contains a direct reference to the vtable data, and is therefore

 // not preserved across GCs.

 class vtableEntry;

 class klassVtable : public ResourceObj {

   KlassHandle  _klass;            // my klass

   int          _tableOffset;      // offset of start of vtable data within klass

   int          _length;           // length of vtable (number of entries)

 #ifndef PRODUCT

   int          _verify_count;     // to make verify faster

 #endif

   // Ordering important, so greater_than (>) can be used as an merge operator.

   enum AccessType {

     acc_private         = 0,

     acc_package_private = 1,

     acc_publicprotected = 2

   };

  public:

   klassVtable(KlassHandle h_klass, void* base, int length) : _klass(h_klass) {

     _tableOffset = (address)base - (address)h_klass(); _length = length;

   }

   // accessors

   vtableEntry* table() const      { return (vtableEntry*)(address(_klass()) + _tableOffset); }

   KlassHandle klass() const       { return _klass;  }

   int length() const              { return _length; }

   inline methodOop method_at(int i) const;

   inline methodOop unchecked_method_at(int i) const;

   inline oop*      adr_method_at(int i) const;

   // searching; all methods return -1 if not found

   int index_of(methodOop m) const                         { return index_of(m, _length); }

   int index_of_miranda(Symbol* name, Symbol* signature);

   void initialize_vtable(bool checkconstraints, TRAPS);   // initialize vtable of a new klass

   // conputes vtable length (in words) and the number of miranda methods

   static void compute_vtable_size_and_num_mirandas(int &vtable_length, int &num_miranda_methods,

                                                    klassOop super, objArrayOop methods,

                                                    AccessFlags class_flags, Handle classloader,

                                                    Symbol* classname, objArrayOop local_interfaces,

                                                    TRAPS);

   // RedefineClasses() API support:

   // If any entry of this vtable points to any of old_methods,

   // replace it with the corresponding new_method.

   // trace_name_printed is set to true if the current call has

   // printed the klass name so that other routines in the adjust_*

   // group don't print the klass name.

   void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,

                              int methods_length, bool * trace_name_printed);

   // Garbage collection

   void oop_follow_contents();

   void oop_adjust_pointers();

 #ifndef SERIALGC

   // Parallel Old

   void oop_follow_contents(ParCompactionManager* cm);

   void oop_update_pointers(ParCompactionManager* cm);

 #endif // SERIALGC

   // Iterators

   void oop_oop_iterate(OopClosure* blk);

   void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);

   // Debugging code

   void print()                                              PRODUCT_RETURN;

   void verify(outputStream* st, bool force = false);

   static void print_statistics()                            PRODUCT_RETURN;

 #ifndef PRODUCT

   bool check_no_old_entries();

   void dump_vtable();

 #endif

  protected:

   friend class vtableEntry;

  private:

   enum { VTABLE_TRANSITIVE_OVERRIDE_VERSION = 51 } ;

   void copy_vtable_to(vtableEntry* start);

   int  initialize_from_super(KlassHandle super);

   int  index_of(methodOop m, int len) const; // same as index_of, but search only up to len

   void put_method_at(methodOop m, int index);

   static bool needs_new_vtable_entry(methodHandle m, klassOop super, Handle classloader, Symbol* classname, AccessFlags access_flags, TRAPS);

   bool update_inherited_vtable(instanceKlass* klass, methodHandle target_method, int super_vtable_len, bool checkconstraints, TRAPS);

  instanceKlass* find_transitive_override(instanceKlass* initialsuper, methodHandle target_method, int vtable_index,

                                          Handle target_loader, Symbol* target_classname, Thread* THREAD);

   // support for miranda methods

   bool is_miranda_entry_at(int i);

   void fill_in_mirandas(int& initialized);

   static bool is_miranda(methodOop m, objArrayOop class_methods, klassOop super);

   static void add_new_mirandas_to_list(GrowableArray<methodOop>* list_of_current_mirandas, objArrayOop current_interface_methods, objArrayOop class_methods, klassOop super);

   static void get_mirandas(GrowableArray<methodOop>* mirandas, klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);

   static int get_num_mirandas(klassOop super, objArrayOop class_methods, objArrayOop local_interfaces);

   void verify_against(outputStream* st, klassVtable* vt, int index);

   inline instanceKlass* ik() const;

 };

 // private helper class for klassVtable

 // description of entry points:

 //    destination is interpreted:

 //      from_compiled_code_entry_point -> c2iadapter

 //      from_interpreter_entry_point   -> interpreter entry point

 //    destination is compiled:

 //      from_compiled_code_entry_point -> nmethod entry point

 //      from_interpreter_entry_point   -> i2cadapter

 class vtableEntry VALUE_OBJ_CLASS_SPEC {

  public:

   // size in words

   static int size() {

     return sizeof(vtableEntry) / sizeof(HeapWord);

   }

   static int method_offset_in_bytes() { return offset_of(vtableEntry, _method); }

   methodOop method() const    { return _method; }

  private:

   methodOop _method;

   void set(methodOop method)  { assert(method != NULL, "use clear"); _method = method; }

   void clear()                { _method = NULL; }

   void print()                                        PRODUCT_RETURN;

   void verify(klassVtable* vt, outputStream* st);

   friend class klassVtable;

 };

 inline methodOop klassVtable::method_at(int i) const {

   assert(i >= 0 && i < _length, "index out of bounds");

   assert(table()[i].method() != NULL, "should not be null");

   assert(oop(table()[i].method())->is_method(), "should be method");

   return table()[i].method();

 }

 inline methodOop klassVtable::unchecked_method_at(int i) const {

   assert(i >= 0 && i < _length, "index out of bounds");

   return table()[i].method();

 }

 inline oop* klassVtable::adr_method_at(int i) const {

   // Allow one past the last entry to be referenced; useful for loop bounds.

   assert(i >= 0 && i <= _length, "index out of bounds");

   return (oop*)(address(table() + i) + vtableEntry::method_offset_in_bytes());

 }

 // --------------------------------------------------------------------------------

 class klassItable;

 class itableMethodEntry;

 class itableOffsetEntry VALUE_OBJ_CLASS_SPEC {

  private:

   klassOop _interface;

   int      _offset;

  public:

   klassOop interface_klass() const { return _interface; }

   int      offset() const          { return _offset; }

   static itableMethodEntry* method_entry(klassOop k, int offset) { return (itableMethodEntry*)(((address)k) + offset); }

   itableMethodEntry* first_method_entry(klassOop k)              { return method_entry(k, _offset); }

   void initialize(klassOop interf, int offset) { _interface = interf; _offset = offset; }

   // Static size and offset accessors

   static int size()                       { return sizeof(itableOffsetEntry) / HeapWordSize; }    // size in words

   static int interface_offset_in_bytes()  { return offset_of(itableOffsetEntry, _interface); }

   static int offset_offset_in_bytes()     { return offset_of(itableOffsetEntry, _offset); }

   friend class klassItable;

 };

 class itableMethodEntry VALUE_OBJ_CLASS_SPEC {

  private:

   methodOop _method;

  public:

   methodOop method() const { return _method; }

   void clear()             { _method = NULL; }

   void initialize(methodOop method);

   // Static size and offset accessors

   static int size()                         { return sizeof(itableMethodEntry) / HeapWordSize; }  // size in words

   static int method_offset_in_bytes()       { return offset_of(itableMethodEntry, _method); }

   friend class klassItable;

 };

 //

 // Format of an itable

 //

 //    ---- offset table ---

 //    klassOop of interface 1             \

 //    offset to vtable from start of oop  / offset table entry

 //    ...

 //    klassOop of interface n             \

 //    offset to vtable from start of oop  / offset table entry

 //    --- vtable for interface 1 ---

 //    methodOop                           \

 //    compiler entry point                / method table entry

 //    ...

 //    methodOop                           \

 //    compiler entry point                / method table entry

 //    -- vtable for interface 2 ---

 //    ...

 //

 class klassItable : public ResourceObj {

  private:

   instanceKlassHandle  _klass;             // my klass

   int                  _table_offset;      // offset of start of itable data within klass (in words)

   int                  _size_offset_table; // size of offset table (in itableOffset entries)

   int                  _size_method_table; // size of methodtable (in itableMethodEntry entries)

   void initialize_itable_for_interface(int method_table_offset, KlassHandle interf_h, bool checkconstraints, TRAPS);

  public:

   klassItable(instanceKlassHandle klass);

   itableOffsetEntry* offset_entry(int i) { assert(0 <= i && i <= _size_offset_table, "index out of bounds");

                                            return &((itableOffsetEntry*)vtable_start())[i]; }

   itableMethodEntry* method_entry(int i) { assert(0 <= i && i <= _size_method_table, "index out of bounds");

                                            return &((itableMethodEntry*)method_start())[i]; }

   int size_offset_table()                { return _size_offset_table; }

   // Initialization

   void initialize_itable(bool checkconstraints, TRAPS);

   // Updates

   void initialize_with_method(methodOop m);

   // RedefineClasses() API support:

   // if any entry of this itable points to any of old_methods,

   // replace it with the corresponding new_method.

   // trace_name_printed is set to true if the current call has

   // printed the klass name so that other routines in the adjust_*

   // group don't print the klass name.

   void adjust_method_entries(methodOop* old_methods, methodOop* new_methods,

                              int methods_length, bool * trace_name_printed);

   // Garbage collection

   void oop_follow_contents();

   void oop_adjust_pointers();

 #ifndef SERIALGC

   // Parallel Old

   void oop_follow_contents(ParCompactionManager* cm);

   void oop_update_pointers(ParCompactionManager* cm);

 #endif // SERIALGC

   // Iterators

   void oop_oop_iterate(OopClosure* blk);

   void oop_oop_iterate_m(OopClosure* blk, MemRegion mr);

   // Setup of itable

   static int compute_itable_size(objArrayHandle transitive_interfaces);

   static void setup_itable_offset_table(instanceKlassHandle klass);

   // Resolving of method to index

   static int compute_itable_index(methodOop m);

   // ...and back again:

   static methodOop method_for_itable_index(klassOop klass, int itable_index);

   // Debugging/Statistics

   static void print_statistics() PRODUCT_RETURN;

  private:

   intptr_t* vtable_start() const { return ((intptr_t*)_klass()) + _table_offset; }

   intptr_t* method_start() const { return vtable_start() + _size_offset_table * itableOffsetEntry::size(); }

   // Helper methods

   static int  calc_itable_size(int num_interfaces, int num_methods) { return (num_interfaces * itableOffsetEntry::size()) + (num_methods * itableMethodEntry::size()); }

   // Statistics

   NOT_PRODUCT(static int  _total_classes;)   // Total no. of classes with itables

   NOT_PRODUCT(static long _total_size;)      // Total no. of bytes used for itables

   static void update_stats(int size) PRODUCT_RETURN NOT_PRODUCT({ _total_classes++; _total_size += size; })

 };

 #endif // SHARE_VM_OOPS_KLASSVTABLE_HPP