jdk8-mips64-public/hotspot: src/share/vm/runtime/handles.hpp@01147d8aac1d

7009923: JSR 292: VM crash in JavaThread::last_frame
Summary: Handle stack overflow before the first frame is called, by printing out the called method and not walking the stack.
Reviewed-by: dholmes, phh, dsamersoff

     1 /*

     2  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.

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

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    25 #ifndef SHARE_VM_RUNTIME_HANDLES_HPP

    26 #define SHARE_VM_RUNTIME_HANDLES_HPP

    28 #include "oops/klass.hpp"

    29 #include "oops/klassOop.hpp"

    30 #include "utilities/top.hpp"

    32 //------------------------------------------------------------------------------------------------------------------------

    33 // In order to preserve oops during garbage collection, they should be

    34 // allocated and passed around via Handles within the VM. A handle is

    35 // simply an extra indirection allocated in a thread local handle area.

    36 //

    37 // A handle is a ValueObj, so it can be passed around as a value, can

    38 // be used as a parameter w/o using &-passing, and can be returned as a

    39 // return value.

    40 //

    41 // oop parameters and return types should be Handles whenever feasible.

    42 //

    43 // Handles are declared in a straight-forward manner, e.g.

    44 //

    45 //   oop obj = ...;

    46 //   Handle h1(obj);              // allocate new handle

    47 //   Handle h2(thread, obj);      // faster allocation when current thread is known

    48 //   Handle h3;                   // declare handle only, no allocation occurs

    49 //   ...

    50 //   h3 = h1;                     // make h3 refer to same indirection as h1

    51 //   oop obj2 = h2();             // get handle value

    52 //   h1->print();                 // invoking operation on oop

    53 //

    54 // Handles are specialized for different oop types to provide extra type

    55 // information and avoid unnecessary casting. For each oop type xxxOop

    56 // there is a corresponding handle called xxxHandle, e.g.

    57 //

    58 //   oop           Handle

    59 //   methodOop     methodHandle

    60 //   instanceOop   instanceHandle

    61 //

    62 // For klassOops, it is often useful to model the Klass hierarchy in order

    63 // to get access to the klass_part without casting. For each xxxKlass there

    64 // is a corresponding handle called xxxKlassHandle, e.g.

    65 //

    66 //   klassOop      Klass           KlassHandle

    67 //   klassOop      methodKlass     methodKlassHandle

    68 //   klassOop      instanceKlass   instanceKlassHandle

    69 //

    71 //------------------------------------------------------------------------------------------------------------------------

    72 // Base class for all handles. Provides overloading of frequently

    73 // used operators for ease of use.

    75 class Handle VALUE_OBJ_CLASS_SPEC {

    76  private:

    77   oop* _handle;

    79  protected:

    80   oop     obj() const                            { return _handle == NULL ? (oop)NULL : *_handle; }

    81   oop     non_null_obj() const                   { assert(_handle != NULL, "resolving NULL handle"); return *_handle; }

    83  public:

    84   // Constructors

    85   Handle()                                       { _handle = NULL; }

    86   Handle(oop obj);

    87 #ifndef ASSERT

    88   Handle(Thread* thread, oop obj);

    89 #else

    90   // Don't inline body with assert for current thread

    91   Handle(Thread* thread, oop obj);

    92 #endif // ASSERT

    94   // General access

    95   oop     operator () () const                   { return obj(); }

    96   oop     operator -> () const                   { return non_null_obj(); }

    97   bool    operator == (oop o) const              { return obj() == o; }

    98   bool    operator == (const Handle& h) const          { return obj() == h.obj(); }

   100   // Null checks

   101   bool    is_null() const                        { return _handle == NULL; }

   102   bool    not_null() const                       { return _handle != NULL; }

   104   // Debugging

   105   void    print()                                { obj()->print(); }

   107   // Direct interface, use very sparingly.

   108   // Used by JavaCalls to quickly convert handles and to create handles static data structures.

   109   // Constructor takes a dummy argument to prevent unintentional type conversion in C++.

   110   Handle(oop *handle, bool dummy)                { _handle = handle; }

   112   // Raw handle access. Allows easy duplication of Handles. This can be very unsafe

   113   // since duplicates is only valid as long as original handle is alive.

   114   oop* raw_value()                               { return _handle; }

   115   static oop raw_resolve(oop *handle)            { return handle == NULL ? (oop)NULL : *handle; }

   116 };

   119 //------------------------------------------------------------------------------------------------------------------------

   120 // Base class for Handles containing klassOops. Provides overloading of frequently

   121 // used operators for ease of use and typed access to the Klass part.

   122 class KlassHandle: public Handle {

   123  protected:

   124   klassOop    obj() const                        { return (klassOop)Handle::obj(); }

   125   klassOop    non_null_obj() const               { return (klassOop)Handle::non_null_obj(); }

   126   Klass*      as_klass() const                   { return non_null_obj()->klass_part(); }

   128  public:

   129   // Constructors

   130   KlassHandle ()                                 : Handle()            {}

   131   KlassHandle (oop obj) : Handle(obj) {

   132     assert(SharedSkipVerify || is_null() || obj->is_klass(), "not a klassOop");

   133   }

   134   KlassHandle (Klass* kl) : Handle(kl ? kl->as_klassOop() : (klassOop)NULL) {

   135     assert(SharedSkipVerify || is_null() || obj()->is_klass(), "not a klassOop");

   136   }

   138   // Faster versions passing Thread

   139   KlassHandle (Thread* thread, oop obj) : Handle(thread, obj) {

   140     assert(SharedSkipVerify || is_null() || obj->is_klass(), "not a klassOop");

   141   }

   142   KlassHandle (Thread *thread, Klass* kl)

   143     : Handle(thread, kl ? kl->as_klassOop() : (klassOop)NULL) {

   144     assert(is_null() || obj()->is_klass(), "not a klassOop");

   145   }

   147   // Direct interface, use very sparingly.

   148   // Used by SystemDictionaryHandles to create handles on existing WKKs.

   149   // The obj of such a klass handle may be null, because the handle is formed

   150   // during system bootstrapping.

   151   KlassHandle(klassOop *handle, bool dummy) : Handle((oop*)handle, dummy) {

   152     assert(SharedSkipVerify || is_null() || obj() == NULL || obj()->is_klass(), "not a klassOop");

   153   }

   155   // General access

   156   klassOop    operator () () const               { return obj(); }

   157   Klass*      operator -> () const               { return as_klass(); }

   158 };

   161 //------------------------------------------------------------------------------------------------------------------------

   162 // Specific Handles for different oop types

   163 #define DEF_HANDLE(type, is_a)                   \

   164   class type##Handle;                            \

   165   class type##Handle: public Handle {            \

   166    protected:                                    \

   167     type##Oop    obj() const                     { return (type##Oop)Handle::obj(); } \

   168     type##Oop    non_null_obj() const            { return (type##Oop)Handle::non_null_obj(); } \

   169                                                  \

   170    public:                                       \

   171     /* Constructors */                           \

   172     type##Handle ()                              : Handle()                 {} \

   173     type##Handle (type##Oop obj) : Handle((oop)obj) {                         \

   174       assert(SharedSkipVerify || is_null() || ((oop)obj)->is_a(),             \

   175              "illegal type");                                                 \

   176     }                                                                         \

   177     type##Handle (Thread* thread, type##Oop obj) : Handle(thread, (oop)obj) { \

   178       assert(SharedSkipVerify || is_null() || ((oop)obj)->is_a(), "illegal type");  \

   179     }                                                                         \

   180     \

   181     /* Special constructor, use sparingly */ \

   182     type##Handle (type##Oop *handle, bool dummy) : Handle((oop*)handle, dummy) {} \

   183                                                  \

   184     /* Operators for ease of use */              \

   185     type##Oop    operator () () const            { return obj(); } \

   186     type##Oop    operator -> () const            { return non_null_obj(); } \

   187   };

   190 DEF_HANDLE(instance         , is_instance         )

   191 DEF_HANDLE(method           , is_method           )

   192 DEF_HANDLE(constMethod      , is_constMethod      )

   193 DEF_HANDLE(methodData       , is_methodData       )

   194 DEF_HANDLE(array            , is_array            )

   195 DEF_HANDLE(constantPool     , is_constantPool     )

   196 DEF_HANDLE(constantPoolCache, is_constantPoolCache)

   197 DEF_HANDLE(objArray         , is_objArray         )

   198 DEF_HANDLE(typeArray        , is_typeArray        )

   200 //------------------------------------------------------------------------------------------------------------------------

   201 // Specific KlassHandles for different Klass types

   203 #define DEF_KLASS_HANDLE(type, is_a)             \

   204   class type##Handle : public KlassHandle {      \

   205    public:                                       \

   206     /* Constructors */                           \

   207     type##Handle ()                              : KlassHandle()           {} \

   208     type##Handle (klassOop obj) : KlassHandle(obj) {                          \

   209       assert(SharedSkipVerify || is_null() || obj->klass_part()->is_a(),      \

   210              "illegal type");                                                 \

   211     }                                                                         \

   212     type##Handle (Thread* thread, klassOop obj) : KlassHandle(thread, obj) {  \

   213       assert(SharedSkipVerify || is_null() || obj->klass_part()->is_a(),      \

   214              "illegal type");                                                 \

   215     }                                                                         \

   216                                                  \

   217     /* Access to klass part */                   \

   218     type*        operator -> () const            { return (type*)obj()->klass_part(); } \

   219                                                  \

   220     static type##Handle cast(KlassHandle h)      { return type##Handle(h()); } \

   221                                                  \

   222   };

   225 DEF_KLASS_HANDLE(instanceKlass         , oop_is_instance_slow )

   226 DEF_KLASS_HANDLE(methodKlass           , oop_is_method        )

   227 DEF_KLASS_HANDLE(constMethodKlass      , oop_is_constMethod   )

   228 DEF_KLASS_HANDLE(klassKlass            , oop_is_klass         )

   229 DEF_KLASS_HANDLE(arrayKlassKlass       , oop_is_arrayKlass    )

   230 DEF_KLASS_HANDLE(objArrayKlassKlass    , oop_is_objArrayKlass )

   231 DEF_KLASS_HANDLE(typeArrayKlassKlass   , oop_is_typeArrayKlass)

   232 DEF_KLASS_HANDLE(arrayKlass            , oop_is_array         )

   233 DEF_KLASS_HANDLE(typeArrayKlass        , oop_is_typeArray_slow)

   234 DEF_KLASS_HANDLE(objArrayKlass         , oop_is_objArray_slow )

   235 DEF_KLASS_HANDLE(constantPoolKlass     , oop_is_constantPool  )

   236 DEF_KLASS_HANDLE(constantPoolCacheKlass, oop_is_constantPool  )

   239 //------------------------------------------------------------------------------------------------------------------------

   240 // Thread local handle area

   242 class HandleArea: public Arena {

   243   friend class HandleMark;

   244   friend class NoHandleMark;

   245   friend class ResetNoHandleMark;

   246 #ifdef ASSERT

   247   int _handle_mark_nesting;

   248   int _no_handle_mark_nesting;

   249 #endif

   250   HandleArea* _prev;          // link to outer (older) area

   251  public:

   252   // Constructor

   253   HandleArea(HandleArea* prev) {

   254     debug_only(_handle_mark_nesting    = 0);

   255     debug_only(_no_handle_mark_nesting = 0);

   256     _prev = prev;

   257   }

   259   // Handle allocation

   260  private:

   261   oop* real_allocate_handle(oop obj) {

   262 #ifdef ASSERT

   263     oop* handle = (oop*) (UseMallocOnly ? internal_malloc_4(oopSize) : Amalloc_4(oopSize));

   264 #else

   265     oop* handle = (oop*) Amalloc_4(oopSize);

   266 #endif

   267     *handle = obj;

   268     return handle;

   269   }

   270  public:

   271 #ifdef ASSERT

   272   oop* allocate_handle(oop obj);

   273 #else

   274   oop* allocate_handle(oop obj) { return real_allocate_handle(obj); }

   275 #endif

   277   // Garbage collection support

   278   void oops_do(OopClosure* f);

   280   // Number of handles in use

   281   size_t used() const     { return Arena::used() / oopSize; }

   283   debug_only(bool no_handle_mark_active() { return _no_handle_mark_nesting > 0; })

   284 };

   287 //------------------------------------------------------------------------------------------------------------------------

   288 // Handles are allocated in a (growable) thread local handle area. Deallocation

   289 // is managed using a HandleMark. It should normally not be necessary to use

   290 // HandleMarks manually.

   291 //

   292 // A HandleMark constructor will record the current handle area top, and the

   293 // desctructor will reset the top, destroying all handles allocated in between.

   294 // The following code will therefore NOT work:

   295 //

   296 //   Handle h;

   297 //   {

   298 //     HandleMark hm;

   299 //     h = Handle(obj);

   300 //   }

   301 //   h()->print();       // WRONG, h destroyed by HandleMark destructor.

   302 //

   303 // If h has to be preserved, it can be converted to an oop or a local JNI handle

   304 // across the HandleMark boundary.

   306 // The base class of HandleMark should have been StackObj but we also heap allocate

   307 // a HandleMark when a thread is created.

   309 class HandleMark {

   310  private:

   311   Thread *_thread;              // thread that owns this mark

   312   HandleArea *_area;            // saved handle area

   313   Chunk *_chunk;                // saved arena chunk

   314   char *_hwm, *_max;            // saved arena info

   315   NOT_PRODUCT(size_t _size_in_bytes;) // size of handle area

   316   // Link to previous active HandleMark in thread

   317   HandleMark* _previous_handle_mark;

   319   void initialize(Thread* thread);                // common code for constructors

   320   void set_previous_handle_mark(HandleMark* mark) { _previous_handle_mark = mark; }

   321   HandleMark* previous_handle_mark() const        { return _previous_handle_mark; }

   323  public:

   324   HandleMark();                            // see handles_inline.hpp

   325   HandleMark(Thread* thread)                      { initialize(thread); }

   326   ~HandleMark();

   328   // Functions used by HandleMarkCleaner

   329   // called in the constructor of HandleMarkCleaner

   330   void push();

   331   // called in the destructor of HandleMarkCleaner

   332   void pop_and_restore();

   333 };

   335 //------------------------------------------------------------------------------------------------------------------------

   336 // A NoHandleMark stack object will verify that no handles are allocated

   337 // in its scope. Enabled in debug mode only.

   339 class NoHandleMark: public StackObj {

   340  public:

   341 #ifdef ASSERT

   342   NoHandleMark();

   343   ~NoHandleMark();

   344 #else

   345   NoHandleMark()  {}

   346   ~NoHandleMark() {}

   347 #endif

   348 };

   351 class ResetNoHandleMark: public StackObj {

   352   int _no_handle_mark_nesting;

   353  public:

   354 #ifdef ASSERT

   355   ResetNoHandleMark();

   356   ~ResetNoHandleMark();

   357 #else

   358   ResetNoHandleMark()  {}

   359   ~ResetNoHandleMark() {}

   360 #endif

   361 };

   363 #endif // SHARE_VM_RUNTIME_HANDLES_HPP

Mercurial > jdk8-mips64-public > hotspot / file revision

src/share/vm/runtime/handles.hpp@01147d8aac1d

src/share/vm/runtime/handles.hpp