1 /*
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   6  * under the terms of the GNU General Public License version 2 only, as
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  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).
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  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     Reason_null_check,            // saw unexpected null or zero divisor (@bci)
  46     Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)
  47     Reason_range_check,           // saw unexpected array index (@bci)
  48     Reason_class_check,           // saw unexpected object class (@bci)
  49     Reason_array_check,           // saw unexpected array class (aastore @bci)
  50     Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)
  51     Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)
  52 
  53     Reason_unloaded,              // unloaded class or constant pool entry
  54     Reason_uninitialized,         // bad class state (uninitialized)
  55     Reason_unreached,             // code is not reached, compiler
  56     Reason_unhandled,             // arbitrary compiler limitation
  57     Reason_constraint,            // arbitrary runtime constraint violated
  58     Reason_div0_check,            // a null_check due to division by zero
  59     Reason_age,                   // nmethod too old; tier threshold reached
  60     Reason_predicate,             // compiler generated predicate failed
  61     Reason_loop_limit_check,      // compiler generated loop limits check failed
  62     Reason_LIMIT,
  63     // Note:  Keep this enum in sync. with _trap_reason_name.
  64     Reason_RECORDED_LIMIT = Reason_bimorphic  // some are not recorded per bc
  65     // Note:  Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of
  66     // DataLayout::trap_bits.  This dependency is enforced indirectly
  67     // via asserts, to avoid excessive direct header-to-header dependencies.
  68     // See Deoptimization::trap_state_reason and class DataLayout.
  69   };
  70 
  71   // What action must be taken by the runtime?
  72   enum DeoptAction {
  73     Action_none,                  // just interpret, do not invalidate nmethod
  74     Action_maybe_recompile,       // recompile the nmethod; need not invalidate
  75     Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile
  76     Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)
  77     Action_make_not_compilable,   // invalidate the nmethod and do not compile
  78     Action_LIMIT
  79     // Note:  Keep this enum in sync. with _trap_action_name.
  80   };
  81 
  82   enum {
  83     _action_bits = 3,
  84     _reason_bits = 5,
  85     _action_shift = 0,
  86     _reason_shift = _action_shift+_action_bits,
  87     BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
  88   };
  89 
  90   enum UnpackType {
  91     Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
  92     Unpack_exception            = 1, // exception is pending
  93     Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)
  94     Unpack_reexecute            = 3  // reexecute bytecode (C1 only)
  95   };
  96 
  97   // Checks all compiled methods. Invalid methods are deleted and
  98   // corresponding activations are deoptimized.
  99   static int deoptimize_dependents();
 100 
 101   // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame
 102   static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);
 103 
 104   private:
 105   // Does the actual work for deoptimizing a single frame
 106   static void deoptimize_single_frame(JavaThread* thread, frame fr);
 107 
 108   // Helper function to revoke biases of all monitors in frame if UseBiasedLocking
 109   // is enabled
 110   static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);
 111   // Helper function to revoke biases of all monitors in frames
 112   // executing in a particular CodeBlob if UseBiasedLocking is enabled
 113   static void revoke_biases_of_monitors(CodeBlob* cb);
 114 
 115 #ifdef COMPILER2
 116   // Support for restoring non-escaping objects
 117   static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);
 118   static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
 119   static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
 120   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);
 121   static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread);
 122   NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)
 123 #endif // COMPILER2
 124 
 125   public:
 126   static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);
 127 
 128   // Interface used for unpacking deoptimized frames
 129 
 130   // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
 131   // This is only a CheapObj to ease debugging after a deopt failure
 132   class UnrollBlock : public CHeapObj {
 133    private:
 134     int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
 135     int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame
 136     int       _number_of_frames;          // Number frames to unroll
 137     int       _total_frame_sizes;         // Total of number*sizes frames
 138     intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack
 139     address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack
 140     intptr_t* _register_block;            // Block for storing callee-saved registers.
 141     BasicType _return_type;               // Tells if we have to restore double or long return value
 142     intptr_t  _initial_fp;                // FP of the sender frame
 143     int       _caller_actual_parameters;  // The number of actual arguments at the
 144                                           // interpreted caller of the deoptimized frame
 145 
 146     // The following fields are used as temps during the unpacking phase
 147     // (which is tight on registers, especially on x86). They really ought
 148     // to be PD variables but that involves moving this class into its own
 149     // file to use the pd include mechanism. Maybe in a later cleanup ...
 150     intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)
 151     intptr_t  _unpack_kind;               // SHOULD BE PD VARIABLE (x86 unpack kind)
 152     intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)
 153    public:
 154     // Constructor
 155     UnrollBlock(int  size_of_deoptimized_frame,
 156                 int  caller_adjustment,
 157                 int  caller_actual_parameters,
 158                 int  number_of_frames,
 159                 intptr_t* frame_sizes,
 160                 address* frames_pcs,
 161                 BasicType return_type);
 162     ~UnrollBlock();
 163 
 164     // Returns where a register is located.
 165     intptr_t* value_addr_at(int register_number) const;
 166 
 167     // Accessors
 168     intptr_t* frame_sizes()  const { return _frame_sizes; }
 169     int number_of_frames()  const { return _number_of_frames; }
 170     address*  frame_pcs()   const { return _frame_pcs ; }
 171 
 172     // Returns the total size of frames
 173     int size_of_frames() const;
 174 
 175     void set_initial_fp(intptr_t fp) { _initial_fp = fp; }
 176 
 177     int caller_actual_parameters() const { return _caller_actual_parameters; }
 178 
 179     // Accessors used by the code generator for the unpack stub.
 180     static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
 181     static int caller_adjustment_offset_in_bytes()         { return offset_of(UnrollBlock, _caller_adjustment);         }
 182     static int number_of_frames_offset_in_bytes()          { return offset_of(UnrollBlock, _number_of_frames);          }
 183     static int frame_sizes_offset_in_bytes()               { return offset_of(UnrollBlock, _frame_sizes);               }
 184     static int total_frame_sizes_offset_in_bytes()         { return offset_of(UnrollBlock, _total_frame_sizes);         }
 185     static int frame_pcs_offset_in_bytes()                 { return offset_of(UnrollBlock, _frame_pcs);                 }
 186     static int register_block_offset_in_bytes()            { return offset_of(UnrollBlock, _register_block);            }
 187     static int return_type_offset_in_bytes()               { return offset_of(UnrollBlock, _return_type);               }
 188     static int counter_temp_offset_in_bytes()              { return offset_of(UnrollBlock, _counter_temp);              }
 189     static int initial_fp_offset_in_bytes()                { return offset_of(UnrollBlock, _initial_fp);                }
 190     static int unpack_kind_offset_in_bytes()               { return offset_of(UnrollBlock, _unpack_kind);               }
 191     static int sender_sp_temp_offset_in_bytes()            { return offset_of(UnrollBlock, _sender_sp_temp);            }
 192 
 193     BasicType return_type() const { return _return_type; }
 194     void print();
 195   };
 196 
 197   //** Returns an UnrollBlock continuing information
 198   // how to make room for the resulting interpreter frames.
 199   // Called by assembly stub after execution has returned to
 200   // deoptimized frame.
 201   // @argument thread.     Thread where stub_frame resides.
 202   // @see OptoRuntime::deoptimization_fetch_unroll_info_C
 203   static UnrollBlock* fetch_unroll_info(JavaThread* thread);
 204 
 205   //** Unpacks vframeArray onto execution stack
 206   // Called by assembly stub after execution has returned to
 207   // deoptimized frame and after the stack unrolling.
 208   // @argument thread.     Thread where stub_frame resides.
 209   // @argument exec_mode.  Determines how execution should be continuted in top frame.
 210   //                       0 means continue after current byte code
 211   //                       1 means exception has happened, handle exception
 212   //                       2 means reexecute current bytecode (for uncommon traps).
 213   // @see OptoRuntime::deoptimization_unpack_frames_C
 214   // Return BasicType of call return type, if any
 215   static BasicType unpack_frames(JavaThread* thread, int exec_mode);
 216 
 217   // Cleans up deoptimization bits on thread after unpacking or in the
 218   // case of an exception.
 219   static void cleanup_deopt_info(JavaThread  *thread,
 220                                  vframeArray * array);
 221 
 222   // Restores callee saved values from deoptimized frame into oldest interpreter frame
 223   // so caller of the deoptimized frame will get back the values it expects.
 224   static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
 225 
 226   //** Performs an uncommon trap for compiled code.
 227   // The top most compiler frame is converted into interpreter frames
 228   static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
 229   // Helper routine that enters the VM and may block
 230   static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);
 231 
 232   //** Deoptimizes the frame identified by id.
 233   // Only called from VMDeoptimizeFrame
 234   // @argument thread.     Thread where stub_frame resides.
 235   // @argument id.         id of frame that should be deoptimized.
 236   static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id);
 237 
 238   // If thread is not the current thread then execute
 239   // VM_DeoptimizeFrame otherwise deoptimize directly.
 240   static void deoptimize_frame(JavaThread* thread, intptr_t* id);
 241 
 242   // Statistics
 243   static void gather_statistics(DeoptReason reason, DeoptAction action,
 244                                 Bytecodes::Code bc = Bytecodes::_illegal);
 245   static void print_statistics();
 246 
 247   // How much room to adjust the last frame's SP by, to make space for
 248   // the callee's interpreter frame (which expects locals to be next to
 249   // incoming arguments)
 250   static int last_frame_adjust(int callee_parameters, int callee_locals);
 251 
 252   // trap_request codes
 253   static DeoptReason trap_request_reason(int trap_request) {
 254     if (trap_request < 0)
 255       return (DeoptReason)
 256         ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
 257     else
 258       // standard reason for unloaded CP entry
 259       return Reason_unloaded;
 260   }
 261   static DeoptAction trap_request_action(int trap_request) {
 262     if (trap_request < 0)
 263       return (DeoptAction)
 264         ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
 265     else
 266       // standard action for unloaded CP entry
 267       return _unloaded_action;
 268   }
 269   static int trap_request_index(int trap_request) {
 270     if (trap_request < 0)
 271       return -1;
 272     else
 273       return trap_request;
 274   }
 275   static int make_trap_request(DeoptReason reason, DeoptAction action,
 276                                int index = -1) {
 277     assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
 278     assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
 279     int trap_request;
 280     if (index != -1)
 281       trap_request = index;
 282     else
 283       trap_request = (~(((reason) << _reason_shift)
 284                         + ((action) << _action_shift)));
 285     assert(reason == trap_request_reason(trap_request), "valid reason");
 286     assert(action == trap_request_action(trap_request), "valid action");
 287     assert(index  == trap_request_index(trap_request),  "valid index");
 288     return trap_request;
 289   }
 290 
 291   // The trap_state stored in a MDO is decoded here.
 292   // It records two items of information.
 293   //  reason:  If a deoptimization happened here, what its reason was,
 294   //           or if there were multiple deopts with differing reasons.
 295   //  recompiled: If a deoptimization here triggered a recompilation.
 296   // Note that not all reasons are recorded per-bci.
 297   static DeoptReason trap_state_reason(int trap_state);
 298   static int  trap_state_has_reason(int trap_state, int reason);
 299   static int  trap_state_add_reason(int trap_state, int reason);
 300   static bool trap_state_is_recompiled(int trap_state);
 301   static int  trap_state_set_recompiled(int trap_state, bool z);
 302   static const char* format_trap_state(char* buf, size_t buflen,
 303                                        int trap_state);
 304 
 305   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
 306     return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
 307   }
 308 
 309   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
 310     if (reason_is_recorded_per_bytecode(reason))
 311       return reason;
 312     else if (reason == Reason_div0_check) // null check due to divide-by-zero?
 313       return Reason_null_check;           // recorded per BCI as a null check
 314     else
 315       return Reason_none;
 316   }
 317 
 318   static const char* trap_reason_name(int reason);
 319   static const char* trap_action_name(int action);
 320   // Format like reason='foo' action='bar' index='123'.
 321   // This is suitable both for XML and for tty output.
 322   static const char* format_trap_request(char* buf, size_t buflen,
 323                                          int trap_request);
 324 
 325   static jint total_deoptimization_count();
 326   static jint deoptimization_count(DeoptReason reason);
 327 
 328   // JVMTI PopFrame support
 329 
 330   // Preserves incoming arguments to the popped frame when it is
 331   // returning to a deoptimized caller
 332   static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
 333 
 334  private:
 335   static methodDataOop get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);
 336   // Update the mdo's count and per-BCI reason bits, returning previous state:
 337   static ProfileData* query_update_method_data(methodDataHandle trap_mdo,
 338                                                int trap_bci,
 339                                                DeoptReason reason,
 340                                                //outputs:
 341                                                uint& ret_this_trap_count,
 342                                                bool& ret_maybe_prior_trap,
 343                                                bool& ret_maybe_prior_recompile);
 344   // class loading support for uncommon trap
 345   static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);
 346   static void load_class_by_index(constantPoolHandle constant_pool, int index);
 347 
 348   static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);
 349 
 350   static DeoptAction _unloaded_action; // == Action_reinterpret;
 351   static const char* _trap_reason_name[Reason_LIMIT];
 352   static const char* _trap_action_name[Action_LIMIT];
 353 
 354   static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
 355   // Note:  Histogram array size is 1-2 Kb.
 356 
 357  public:
 358   static void update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason);
 359 };
 360 
 361 class DeoptimizationMarker : StackObj {  // for profiling
 362   static bool _is_active;
 363 public:
 364   DeoptimizationMarker()  { _is_active = true; }
 365   ~DeoptimizationMarker() { _is_active = false; }
 366   static bool is_active() { return _is_active; }
 367 };
 368 
 369 #endif // SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP