1 /*

     2  * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    20  * CA 95054 USA or visit www.sun.com if you need additional information or

    21  * have any questions.

    22  *

    23  */

    24 

    25 class ProfileData;

    26 class vframeArray;

    27 class MonitorValue;

    28 class ObjectValue;

    29 

    30 class Deoptimization : AllStatic {

    31  public:

    32   // What condition caused the deoptimization?

    33   enum DeoptReason {

    34     Reason_many = -1,             // indicates presence of several reasons

    35     Reason_none = 0,              // indicates absence of a relevant deopt.

    36     Reason_null_check,            // saw unexpected null or zero divisor (@bci)

    37     Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)

    38     Reason_range_check,           // saw unexpected array index (@bci)

    39     Reason_class_check,           // saw unexpected object class (@bci)

    40     Reason_array_check,           // saw unexpected array class (aastore @bci)

    41     Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)

    42     Reason_unloaded,              // unloaded class or constant pool entry

    43     Reason_uninitialized,         // bad class state (uninitialized)

    44     Reason_unreached,             // code is not reached, compiler

    45     Reason_unhandled,             // arbitrary compiler limitation

    46     Reason_constraint,            // arbitrary runtime constraint violated

    47     Reason_div0_check,            // a null_check due to division by zero

    48     Reason_age,                   // nmethod too old; tier threshold reached

    49     Reason_LIMIT,

    50     // Note:  Keep this enum in sync. with _trap_reason_name.

    51     Reason_RECORDED_LIMIT = Reason_unloaded   // some are not recorded per bc

    52     // Note:  Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of

    53     // DataLayout::trap_bits.  This dependency is enforced indirectly

    54     // via asserts, to avoid excessive direct header-to-header dependencies.

    55     // See Deoptimization::trap_state_reason and class DataLayout.

    56   };

    57 

    58   // What action must be taken by the runtime?

    59   enum DeoptAction {

    60     Action_none,                  // just interpret, do not invalidate nmethod

    61     Action_maybe_recompile,       // recompile the nmethod; need not invalidate

    62     Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile

    63     Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)

    64     Action_make_not_compilable,   // invalidate the nmethod and do not compile

    65     Action_LIMIT

    66     // Note:  Keep this enum in sync. with _trap_action_name.

    67   };

    68 

    69   enum {

    70     _action_bits = 3,

    71     _reason_bits = 4,

    72     _action_shift = 0,

    73     _reason_shift = _action_shift+_action_bits,

    74     BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist

    75   };

    76 

    77   enum UnpackType {

    78     Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack

    79     Unpack_exception            = 1, // exception is pending

    80     Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)

    81     Unpack_reexecute            = 3  // reexecute bytecode (C1 only)

    82   };

    83 

    84   // Checks all compiled methods. Invalid methods are deleted and

    85   // corresponding activations are deoptimized.

    86   static int deoptimize_dependents();

    87 

    88   // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame

    89   static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);

    90 

    91   private:

    92   // Does the actual work for deoptimizing a single frame

    93   static void deoptimize_single_frame(JavaThread* thread, frame fr);

    94 

    95   // Helper function to revoke biases of all monitors in frame if UseBiasedLocking

    96   // is enabled

    97   static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);

    98   // Helper function to revoke biases of all monitors in frames

    99   // executing in a particular CodeBlob if UseBiasedLocking is enabled

   100   static void revoke_biases_of_monitors(CodeBlob* cb);

   101 

   102 #ifdef COMPILER2

   103   // Support for restoring non-escaping objects

   104   static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);

   105   static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);

   106   static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);

   107   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);

   108   static void relock_objects(frame* fr, RegisterMap* reg_map, GrowableArray<MonitorValue*>* monitors);

   109   NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)

   110 #endif // COMPILER2

   111 

   112   public:

   113   static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);

   114 

   115   // Interface used for unpacking deoptimized frames

   116 

   117   // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).

   118   // This is only a CheapObj to ease debugging after a deopt failure

   119   class UnrollBlock : public CHeapObj {

   120    private:

   121     int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame

   122     int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame

   123     int       _number_of_frames;          // Number frames to unroll

   124     int       _total_frame_sizes;         // Total of number*sizes frames

   125     intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack

   126     address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack

   127     intptr_t* _register_block;            // Block for storing callee-saved registers.

   128     BasicType _return_type;               // Tells if we have to restore double or long return value

   129     // The following fields are used as temps during the unpacking phase

   130     // (which is tight on registers, especially on x86). They really ought

   131     // to be PD variables but that involves moving this class into its own

   132     // file to use the pd include mechanism. Maybe in a later cleanup ...

   133     intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)

   134     intptr_t  _initial_fp;                // SHOULD BE PD VARIABLE (x86/c2 initial ebp)

   135     intptr_t  _unpack_kind;               // SHOULD BE PD VARIABLE (x86 unpack kind)

   136     intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)

   137    public:

   138     // Constructor

   139     UnrollBlock(int  size_of_deoptimized_frame,

   140                 int  caller_adjustment,

   141                 int  number_of_frames,

   142                 intptr_t* frame_sizes,

   143                 address* frames_pcs,

   144                 BasicType return_type);

   145     ~UnrollBlock();

   146 

   147     // Returns where a register is located.

   148     intptr_t* value_addr_at(int register_number) const;

   149 

   150     // Accessors

   151     intptr_t* frame_sizes()  const { return _frame_sizes; }

   152     int number_of_frames()  const { return _number_of_frames; }

   153     address*  frame_pcs()   const { return _frame_pcs ; }

   154 

   155     // Returns the total size of frames

   156     int size_of_frames() const;

   157 

   158     // Accessors used by the code generator for the unpack stub.

   159     static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }

   160     static int caller_adjustment_offset_in_bytes()         { return offset_of(UnrollBlock, _caller_adjustment);         }

   161     static int number_of_frames_offset_in_bytes()          { return offset_of(UnrollBlock, _number_of_frames);          }

   162     static int frame_sizes_offset_in_bytes()               { return offset_of(UnrollBlock, _frame_sizes);               }

   163     static int total_frame_sizes_offset_in_bytes()         { return offset_of(UnrollBlock, _total_frame_sizes);         }

   164     static int frame_pcs_offset_in_bytes()                 { return offset_of(UnrollBlock, _frame_pcs);                 }

   165     static int register_block_offset_in_bytes()            { return offset_of(UnrollBlock, _register_block);            }

   166     static int return_type_offset_in_bytes()               { return offset_of(UnrollBlock, _return_type);               }

   167     static int counter_temp_offset_in_bytes()              { return offset_of(UnrollBlock, _counter_temp);              }

   168     static int initial_fp_offset_in_bytes()                { return offset_of(UnrollBlock, _initial_fp);                }

   169     static int unpack_kind_offset_in_bytes()               { return offset_of(UnrollBlock, _unpack_kind);               }

   170     static int sender_sp_temp_offset_in_bytes()            { return offset_of(UnrollBlock, _sender_sp_temp);            }

   171 

   172     BasicType return_type() const { return _return_type; }

   173     void print();

   174   };

   175 

   176   //** Returns an UnrollBlock continuing information

   177   // how to make room for the resulting interpreter frames.

   178   // Called by assembly stub after execution has returned to

   179   // deoptimized frame.

   180   // @argument thread.     Thread where stub_frame resides.

   181   // @see OptoRuntime::deoptimization_fetch_unroll_info_C

   182   static UnrollBlock* fetch_unroll_info(JavaThread* thread);

   183 

   184   //** Unpacks vframeArray onto execution stack

   185   // Called by assembly stub after execution has returned to

   186   // deoptimized frame and after the stack unrolling.

   187   // @argument thread.     Thread where stub_frame resides.

   188   // @argument exec_mode.  Determines how execution should be continuted in top frame.

   189   //                       0 means continue after current byte code

   190   //                       1 means exception has happened, handle exception

   191   //                       2 means reexecute current bytecode (for uncommon traps).

   192   // @see OptoRuntime::deoptimization_unpack_frames_C

   193   // Return BasicType of call return type, if any

   194   static BasicType unpack_frames(JavaThread* thread, int exec_mode);

   195 

   196   // Cleans up deoptimization bits on thread after unpacking or in the

   197   // case of an exception.

   198   static void cleanup_deopt_info(JavaThread  *thread,

   199                                  vframeArray * array);

   200 

   201   // Restores callee saved values from deoptimized frame into oldest interpreter frame

   202   // so caller of the deoptimized frame will get back the values it expects.

   203   static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);

   204 

   205   //** Performs an uncommon trap for compiled code.

   206   // The top most compiler frame is converted into interpreter frames

   207   static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);

   208   // Helper routine that enters the VM and may block

   209   static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);

   210 

   211   //** Deoptimizes the frame identified by id.

   212   // Only called from VMDeoptimizeFrame

   213   // @argument thread.     Thread where stub_frame resides.

   214   // @argument id.         id of frame that should be deoptimized.

   215   static void deoptimize_frame(JavaThread* thread, intptr_t* id);

   216 

   217   // Statistics

   218   static void gather_statistics(DeoptReason reason, DeoptAction action,

   219                                 Bytecodes::Code bc = Bytecodes::_illegal);

   220   static void print_statistics();

   221 

   222   // How much room to adjust the last frame's SP by, to make space for

   223   // the callee's interpreter frame (which expects locals to be next to

   224   // incoming arguments)

   225   static int last_frame_adjust(int callee_parameters, int callee_locals);

   226 

   227   // trap_request codes

   228   static DeoptReason trap_request_reason(int trap_request) {

   229     if (trap_request < 0)

   230       return (DeoptReason)

   231         ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));

   232     else

   233       // standard reason for unloaded CP entry

   234       return Reason_unloaded;

   235   }

   236   static DeoptAction trap_request_action(int trap_request) {

   237     if (trap_request < 0)

   238       return (DeoptAction)

   239         ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));

   240     else

   241       // standard action for unloaded CP entry

   242       return _unloaded_action;

   243   }

   244   static int trap_request_index(int trap_request) {

   245     if (trap_request < 0)

   246       return -1;

   247     else

   248       return trap_request;

   249   }

   250   static int make_trap_request(DeoptReason reason, DeoptAction action,

   251                                int index = -1) {

   252     assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");

   253     assert((1 << _action_bits) >= Action_LIMIT, "enough bits");

   254     int trap_request;

   255     if (index != -1)

   256       trap_request = index;

   257     else

   258       trap_request = (~(((reason) << _reason_shift)

   259                         + ((action) << _action_shift)));

   260     assert(reason == trap_request_reason(trap_request), "valid reason");

   261     assert(action == trap_request_action(trap_request), "valid action");

   262     assert(index  == trap_request_index(trap_request),  "valid index");

   263     return trap_request;

   264   }

   265 

   266   // The trap_state stored in a MDO is decoded here.

   267   // It records two items of information.

   268   //  reason:  If a deoptimization happened here, what its reason was,

   269   //           or if there were multiple deopts with differing reasons.

   270   //  recompiled: If a deoptimization here triggered a recompilation.

   271   // Note that not all reasons are recorded per-bci.

   272   static DeoptReason trap_state_reason(int trap_state);

   273   static int  trap_state_has_reason(int trap_state, int reason);

   274   static int  trap_state_add_reason(int trap_state, int reason);

   275   static bool trap_state_is_recompiled(int trap_state);

   276   static int  trap_state_set_recompiled(int trap_state, bool z);

   277   static const char* format_trap_state(char* buf, size_t buflen,

   278                                        int trap_state);

   279 

   280   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {

   281     return reason > Reason_none && reason < Reason_RECORDED_LIMIT;

   282   }

   283 

   284   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {

   285     if (reason_is_recorded_per_bytecode(reason))

   286       return reason;

   287     else if (reason == Reason_div0_check) // null check due to divide-by-zero?

   288       return Reason_null_check;           // recorded per BCI as a null check

   289     else

   290       return Reason_none;

   291   }

   292 

   293   static const char* trap_reason_name(int reason);

   294   static const char* trap_action_name(int action);

   295   // Format like reason='foo' action='bar' index='123'.

   296   // This is suitable both for XML and for tty output.

   297   static const char* format_trap_request(char* buf, size_t buflen,

   298                                          int trap_request);

   299 

   300   static jint total_deoptimization_count();

   301   static jint deoptimization_count(DeoptReason reason);

   302 

   303   // JVMTI PopFrame support

   304 

   305   // Preserves incoming arguments to the popped frame when it is

   306   // returning to a deoptimized caller

   307   static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);

   308 

   309  private:

   310   enum {

   311     _no_count = -1

   312   };

   313 

   314   static void reset_invocation_counter(ScopeDesc* trap_scope, jint count = _no_count);

   315 

   316   static methodDataOop get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);

   317   // Update the mdo's count and per-BCI reason bits, returning previous state:

   318   static ProfileData* query_update_method_data(methodDataHandle trap_mdo,

   319                                                int trap_bci,

   320                                                DeoptReason reason,

   321                                                //outputs:

   322                                                uint& ret_this_trap_count,

   323                                                bool& ret_maybe_prior_trap,

   324                                                bool& ret_maybe_prior_recompile);

   325   // class loading support for uncommon trap

   326   static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);

   327   static void load_class_by_index(constantPoolHandle constant_pool, int index);

   328 

   329   static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);

   330 

   331   static DeoptAction _unloaded_action; // == Action_reinterpret;

   332   static const char* _trap_reason_name[Reason_LIMIT];

   333   static const char* _trap_action_name[Action_LIMIT];

   334 

   335   static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];

   336   // Note:  Histogram array size is 1-2 Kb.

   337 

   338  public:

   339   static void update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason);

   340 };

   341 

   342 class DeoptimizationMarker : StackObj {  // for profiling

   343   static bool _is_active;

   344 public:

   345   DeoptimizationMarker()  { _is_active = true; }

   346   ~DeoptimizationMarker() { _is_active = false; }

   347   static bool is_active() { return _is_active; }

   348 };