1 /*

     2  * Copyright (c) 1997, 2017, 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  */

    24 

    25 #ifndef SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP

    26 #define SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP

    27 

    28 #include "memory/allocation.hpp"

    29 #include "runtime/frame.inline.hpp"

    30 

    31 class ProfileData;

    32 class vframeArray;

    33 class MonitorValue;

    34 class ObjectValue;

    35 

    36 class Deoptimization : AllStatic {

    37   friend class VMStructs;

    38 

    39  public:

    40   // What condition caused the deoptimization?

    41   enum DeoptReason {

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

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

    44     // Next 7 reasons are recorded per bytecode in DataLayout::trap_bits.

    45     // This is more complicated for JVMCI as JVMCI may deoptimize to *some* bytecode before the

    46     // bytecode that actually caused the deopt (with inlining, JVMCI may even deoptimize to a

    47     // bytecode in another method):

    48     //  - bytecode y in method b() causes deopt

    49     //  - JVMCI deoptimizes to bytecode x in method a()

    50     // -> the deopt reason will be recorded for method a() at bytecode x

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

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

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

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

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

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

    57     Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)

    58 

    59 #if INCLUDE_JVMCI

    60     Reason_unreached0             = Reason_null_assert,

    61     Reason_type_checked_inlining  = Reason_intrinsic,

    62     Reason_optimized_type_check   = Reason_bimorphic,

    63 #endif

    64 

    65     // recorded per method

    66     Reason_unloaded,              // unloaded class or constant pool entry

    67     Reason_uninitialized,         // bad class state (uninitialized)

    68     Reason_unreached,             // code is not reached, compiler

    69     Reason_unhandled,             // arbitrary compiler limitation

    70     Reason_constraint,            // arbitrary runtime constraint violated

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

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

    73     Reason_predicate,             // compiler generated predicate failed

    74     Reason_loop_limit_check,      // compiler generated loop limits check failed

    75     Reason_speculate_class_check, // saw unexpected object class from type speculation

    76     Reason_speculate_null_check,  // saw unexpected null from type speculation

    77     Reason_speculate_null_assert, // saw unexpected null from type speculation

    78     Reason_rtm_state_change,      // rtm state change detected

    79     Reason_unstable_if,           // a branch predicted always false was taken

    80     Reason_unstable_fused_if,     // fused two ifs that had each one untaken branch. One is now taken.

    81 #if INCLUDE_JVMCI

    82     Reason_aliasing,              // optimistic assumption about aliasing failed

    83     Reason_transfer_to_interpreter, // explicit transferToInterpreter()

    84     Reason_not_compiled_exception_handler,

    85     Reason_unresolved,

    86     Reason_jsr_mismatch,

    87 #endif

    88 

    89     // Reason_tenured is counted separately, add normal counted Reasons above.

    90     // Related to MethodData::_trap_hist_limit where Reason_tenured isn't included

    91     Reason_tenured,               // age of the code has reached the limit

    92     Reason_LIMIT,

    93 

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

    95     Reason_RECORDED_LIMIT = Reason_bimorphic  // some are not recorded per bc

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

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

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

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

   100   };

   101 

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

   103   enum DeoptAction {

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

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

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

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

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

   109     Action_LIMIT

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

   111   };

   112 

   113   enum {

   114     _action_bits = 3,

   115     _reason_bits = 5,

   116     _debug_id_bits = 23,

   117     _action_shift = 0,

   118     _reason_shift = _action_shift+_action_bits,

   119     _debug_id_shift = _reason_shift+_reason_bits,

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

   121   };

   122 

   123   enum UnpackType {

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

   125     Unpack_exception            = 1, // exception is pending

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

   127     Unpack_reexecute            = 3, // reexecute bytecode (C1 only)

   128     Unpack_LIMIT                = 4

   129   };

   130 

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

   132   // corresponding activations are deoptimized.

   133   static int deoptimize_dependents();

   134 

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

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

   137   static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map, DeoptReason reason);

   138 

   139 #if INCLUDE_JVMCI

   140   static address deoptimize_for_missing_exception_handler(CompiledMethod* cm);

   141 #endif

   142 

   143   private:

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

   145   static void deoptimize_single_frame(JavaThread* thread, frame fr, DeoptReason reason);

   146 

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

   148   // is enabled

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

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

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

   152   static void revoke_biases_of_monitors(CodeBlob* cb);

   153 

   154 #if defined(COMPILER2) || INCLUDE_JVMCI

   155 JVMCI_ONLY(public:)

   156 

   157   // Support for restoring non-escaping objects

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

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

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

   161   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, bool realloc_failures, bool skip_internal);

   162   static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread, bool realloc_failures);

   163   static void pop_frames_failed_reallocs(JavaThread* thread, vframeArray* array);

   164   NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects, bool realloc_failures);)

   165 #endif // COMPILER2 || INCLUDE_JVMCI

   166 

   167   public:

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

   169 

   170   // Interface used for unpacking deoptimized frames

   171 

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

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

   174   class UnrollBlock : public CHeapObj<mtCompiler> {

   175     friend class VMStructs;

   176     friend class JVMCIVMStructs;

   177    private:

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

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

   180     int       _number_of_frames;          // Number frames to unroll

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

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

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

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

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

   186     intptr_t  _initial_info;              // Platform dependent data for the sender frame (was FP on x86)

   187     int       _caller_actual_parameters;  // The number of actual arguments at the

   188                                           // interpreted caller of the deoptimized frame

   189     int       _unpack_kind;               // exec_mode that can be changed during fetch_unroll_info

   190 

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

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

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

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

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

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

   197    public:

   198     // Constructor

   199     UnrollBlock(int  size_of_deoptimized_frame,

   200                 int  caller_adjustment,

   201                 int  caller_actual_parameters,

   202                 int  number_of_frames,

   203                 intptr_t* frame_sizes,

   204                 address* frames_pcs,

   205                 BasicType return_type,

   206                 int unpack_kind);

   207     ~UnrollBlock();

   208 

   209     // Returns where a register is located.

   210     intptr_t* value_addr_at(int register_number) const;

   211 

   212     // Accessors

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

   214     int number_of_frames()  const { return _number_of_frames; }

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

   216     int  unpack_kind()   const { return _unpack_kind; }

   217 

   218     // Returns the total size of frames

   219     int size_of_frames() const;

   220 

   221     void set_initial_info(intptr_t info) { _initial_info = info; }

   222 

   223     int caller_actual_parameters() const { return _caller_actual_parameters; }

   224 

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

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

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

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

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

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

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

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

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

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

   235     static int initial_info_offset_in_bytes()              { return offset_of(UnrollBlock, _initial_info);              }

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

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

   238 

   239     BasicType return_type() const { return _return_type; }

   240     void print();

   241   };

   242 

   243   //** Returns an UnrollBlock continuing information

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

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

   246   // deoptimized frame.

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

   248   // @see OptoRuntime::deoptimization_fetch_unroll_info_C

   249   static UnrollBlock* fetch_unroll_info(JavaThread* thread, int exec_mode);

   250 

   251   //** Unpacks vframeArray onto execution stack

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

   253   // deoptimized frame and after the stack unrolling.

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

   255   // @argument exec_mode.  Determines how execution should be continued in top frame.

   256   //                       0 means continue after current byte code

   257   //                       1 means exception has happened, handle exception

   258   //                       2 means reexecute current bytecode (for uncommon traps).

   259   // @see OptoRuntime::deoptimization_unpack_frames_C

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

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

   262 

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

   264   // case of an exception.

   265   static void cleanup_deopt_info(JavaThread  *thread,

   266                                  vframeArray * array);

   267 

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

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

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

   271 

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

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

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

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

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

   277 

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

   279   // Only called from VMDeoptimizeFrame

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

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

   282   static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id, DeoptReason reason);

   283 

   284   // if thread is not the current thread then execute

   285   // VM_DeoptimizeFrame otherwise deoptimize directly.

   286   static void deoptimize_frame(JavaThread* thread, intptr_t* id, DeoptReason reason);

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

   288 

   289   // Statistics

   290   static void gather_statistics(DeoptReason reason, DeoptAction action,

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

   292   static void print_statistics();

   293 

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

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

   296   // incoming arguments)

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

   298 

   299   // trap_request codes

   300   static DeoptReason trap_request_reason(int trap_request) {

   301     if (trap_request < 0)

   302       return (DeoptReason)

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

   304     else

   305       // standard reason for unloaded CP entry

   306       return Reason_unloaded;

   307   }

   308   static DeoptAction trap_request_action(int trap_request) {

   309     if (trap_request < 0)

   310       return (DeoptAction)

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

   312     else

   313       // standard action for unloaded CP entry

   314       return _unloaded_action;

   315   }

   316   static int trap_request_debug_id(int trap_request) {

   317     if (trap_request < 0) {

   318       return ((~(trap_request) >> _debug_id_shift) & right_n_bits(_debug_id_bits));

   319     } else {

   320       // standard action for unloaded CP entry

   321       return 0;

   322     }

   323   }

   324   static int trap_request_index(int trap_request) {

   325     if (trap_request < 0)

   326       return -1;

   327     else

   328       return trap_request;

   329   }

   330   static int make_trap_request(DeoptReason reason, DeoptAction action,

   331                                int index = -1) {

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

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

   334     int trap_request;

   335     if (index != -1)

   336       trap_request = index;

   337     else

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

   339                         + ((action) << _action_shift)));

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

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

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

   343     return trap_request;

   344   }

   345 

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

   347   // It records two items of information.

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

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

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

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

   352   static DeoptReason trap_state_reason(int trap_state);

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

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

   355   static bool trap_state_is_recompiled(int trap_state);

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

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

   358                                        int trap_state);

   359 

   360   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {

   361     return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;

   362   }

   363 

   364   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {

   365     if (reason_is_recorded_per_bytecode(reason))

   366       return reason;

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

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

   369     else if (reason == Reason_speculate_class_check)

   370       return Reason_class_check;

   371     else if (reason == Reason_speculate_null_check)

   372       return Reason_null_check;

   373     else if (reason == Reason_speculate_null_assert)

   374       return Reason_null_assert;

   375     else if (reason == Reason_unstable_if)

   376       return Reason_intrinsic;

   377     else if (reason == Reason_unstable_fused_if)

   378       return Reason_range_check;

   379     else

   380       return Reason_none;

   381   }

   382 

   383   static bool reason_is_speculate(int reason) {

   384     if (reason == Reason_speculate_class_check ||

   385         reason == Reason_speculate_null_check ||

   386         reason == Reason_speculate_null_assert) {

   387       return true;

   388     }

   389     return false;

   390   }

   391 

   392   static DeoptReason reason_null_check(bool speculative) {

   393     return speculative ? Deoptimization::Reason_speculate_null_check : Deoptimization::Reason_null_check;

   394   }

   395 

   396   static DeoptReason reason_class_check(bool speculative) {

   397     return speculative ? Deoptimization::Reason_speculate_class_check : Deoptimization::Reason_class_check;

   398   }

   399 

   400   static DeoptReason reason_null_assert(bool speculative) {

   401     return speculative ? Deoptimization::Reason_speculate_null_assert : Deoptimization::Reason_null_assert;

   402   }

   403 

   404   static uint per_method_trap_limit(int reason) {

   405     return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;

   406   }

   407 

   408   static const char* trap_reason_name(int reason);

   409   static const char* trap_action_name(int action);

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

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

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

   413                                          int trap_request);

   414 

   415   static jint total_deoptimization_count();

   416   static jint deoptimization_count(DeoptReason reason);

   417 

   418   // JVMTI PopFrame support

   419 

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

   421   // returning to a deoptimized caller

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

   423 

   424   static MethodData* get_method_data(JavaThread* thread, const methodHandle& m, bool create_if_missing);

   425  private:

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

   427   static ProfileData* query_update_method_data(MethodData* trap_mdo,

   428                                                int trap_bci,

   429                                                DeoptReason reason,

   430                                                bool update_total_trap_count,

   431 #if INCLUDE_JVMCI

   432                                                bool is_osr,

   433 #endif

   434                                                Method* compiled_method,

   435                                                //outputs:

   436                                                uint& ret_this_trap_count,

   437                                                bool& ret_maybe_prior_trap,

   438                                                bool& ret_maybe_prior_recompile);

   439   // class loading support for uncommon trap

   440   static void load_class_by_index(const constantPoolHandle& constant_pool, int index, TRAPS);

   441   static void load_class_by_index(const constantPoolHandle& constant_pool, int index);

   442 

   443   static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread, int exec_mode);

   444 

   445   static DeoptAction _unloaded_action; // == Action_reinterpret;

   446   static const char* _trap_reason_name[];

   447   static const char* _trap_action_name[];

   448 

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

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

   451 

   452  public:

   453   static void update_method_data_from_interpreter(MethodData* trap_mdo, int trap_bci, int reason);

   454 };

   455 

   456 class DeoptimizationMarker : StackObj {  // for profiling

   457   static bool _is_active;

   458 public:

   459   DeoptimizationMarker()  { _is_active = true; }

   460   ~DeoptimizationMarker() { _is_active = false; }

   461   static bool is_active() { return _is_active; }

   462 };

   463 

   464 #endif // SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP