1 /*
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  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  public:
  38   // What condition caused the deoptimization?
  39   enum DeoptReason {
  40     Reason_many = -1,             // indicates presence of several reasons
  41     Reason_none = 0,              // indicates absence of a relevant deopt.
  42     // Next 7 reasons are recorded per bytecode in DataLayout::trap_bits
  43     Reason_null_check,            // saw unexpected null or zero divisor (@bci)
  44     Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)
  45     Reason_range_check,           // saw unexpected array index (@bci)
  46     Reason_class_check,           // saw unexpected object class (@bci)
  47     Reason_array_check,           // saw unexpected array class (aastore @bci)
  48     Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)
  49     Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)
  50 
  51     Reason_unloaded,              // unloaded class or constant pool entry
  52     Reason_uninitialized,         // bad class state (uninitialized)
  53     Reason_unreached,             // code is not reached, compiler
  54     Reason_unhandled,             // arbitrary compiler limitation
  55     Reason_constraint,            // arbitrary runtime constraint violated
  56     Reason_div0_check,            // a null_check due to division by zero
  57     Reason_age,                   // nmethod too old; tier threshold reached
  58     Reason_predicate,             // compiler generated predicate failed
  59     Reason_loop_limit_check,      // compiler generated loop limits check failed
  60     Reason_LIMIT,
  61     // Note:  Keep this enum in sync. with _trap_reason_name.
  62     Reason_RECORDED_LIMIT = Reason_bimorphic  // some are not recorded per bc
  63     // Note:  Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of
  64     // DataLayout::trap_bits.  This dependency is enforced indirectly
  65     // via asserts, to avoid excessive direct header-to-header dependencies.
  66     // See Deoptimization::trap_state_reason and class DataLayout.
  67   };
  68 
  69   // What action must be taken by the runtime?
  70   enum DeoptAction {
  71     Action_none,                  // just interpret, do not invalidate nmethod
  72     Action_maybe_recompile,       // recompile the nmethod; need not invalidate
  73     Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile
  74     Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)
  75     Action_make_not_compilable,   // invalidate the nmethod and do not compile
  76     Action_LIMIT
  77     // Note:  Keep this enum in sync. with _trap_action_name.
  78   };
  79 
  80   enum {
  81     _action_bits = 3,
  82     _reason_bits = 5,
  83     _action_shift = 0,
  84     _reason_shift = _action_shift+_action_bits,
  85     BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
  86   };
  87 
  88   enum UnpackType {
  89     Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
  90     Unpack_exception            = 1, // exception is pending
  91     Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)
  92     Unpack_reexecute            = 3  // reexecute bytecode (C1 only)
  93   };
  94 
  95   // Checks all compiled methods. Invalid methods are deleted and
  96   // corresponding activations are deoptimized.
  97   static int deoptimize_dependents();
  98 
  99   // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame
 100   static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);
 101 
 102   private:
 103   // Does the actual work for deoptimizing a single frame
 104   static void deoptimize_single_frame(JavaThread* thread, frame fr);
 105 
 106   // Helper function to revoke biases of all monitors in frame if UseBiasedLocking
 107   // is enabled
 108   static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);
 109   // Helper function to revoke biases of all monitors in frames
 110   // executing in a particular CodeBlob if UseBiasedLocking is enabled
 111   static void revoke_biases_of_monitors(CodeBlob* cb);
 112 
 113 #ifdef COMPILER2
 114   // Support for restoring non-escaping objects
 115   static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);
 116   static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
 117   static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
 118   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);
 119   static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread);
 120   NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)
 121 #endif // COMPILER2
 122 
 123   public:
 124   static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);
 125 
 126   // Interface used for unpacking deoptimized frames
 127 
 128   // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
 129   // This is only a CheapObj to ease debugging after a deopt failure
 130   class UnrollBlock : public CHeapObj {
 131    private:
 132     int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
 133     int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame
 134     int       _number_of_frames;          // Number frames to unroll
 135     int       _total_frame_sizes;         // Total of number*sizes frames
 136     intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack
 137     address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack
 138     intptr_t* _register_block;            // Block for storing callee-saved registers.
 139     BasicType _return_type;               // Tells if we have to restore double or long return value
 140     intptr_t  _initial_fp;                // FP of the sender frame
 141     int       _caller_actual_parameters;  // The number of actual arguments at the
 142                                           // interpreted caller of the deoptimized frame
 143 
 144     // The following fields are used as temps during the unpacking phase
 145     // (which is tight on registers, especially on x86). They really ought
 146     // to be PD variables but that involves moving this class into its own
 147     // file to use the pd include mechanism. Maybe in a later cleanup ...
 148     intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)
 149     intptr_t  _unpack_kind;               // SHOULD BE PD VARIABLE (x86 unpack kind)
 150     intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)
 151    public:
 152     // Constructor
 153     UnrollBlock(int  size_of_deoptimized_frame,
 154                 int  caller_adjustment,
 155                 int  caller_actual_parameters,
 156                 int  number_of_frames,
 157                 intptr_t* frame_sizes,
 158                 address* frames_pcs,
 159                 BasicType return_type);
 160     ~UnrollBlock();
 161 
 162     // Returns where a register is located.
 163     intptr_t* value_addr_at(int register_number) const;
 164 
 165     // Accessors
 166     intptr_t* frame_sizes()  const { return _frame_sizes; }
 167     int number_of_frames()  const { return _number_of_frames; }
 168     address*  frame_pcs()   const { return _frame_pcs ; }
 169 
 170     // Returns the total size of frames
 171     int size_of_frames() const;
 172 
 173     void set_initial_fp(intptr_t fp) { _initial_fp = fp; }
 174 
 175     int caller_actual_parameters() const { return _caller_actual_parameters; }
 176 
 177     // Accessors used by the code generator for the unpack stub.
 178     static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
 179     static int caller_adjustment_offset_in_bytes()         { return offset_of(UnrollBlock, _caller_adjustment);         }
 180     static int number_of_frames_offset_in_bytes()          { return offset_of(UnrollBlock, _number_of_frames);          }
 181     static int frame_sizes_offset_in_bytes()               { return offset_of(UnrollBlock, _frame_sizes);               }
 182     static int total_frame_sizes_offset_in_bytes()         { return offset_of(UnrollBlock, _total_frame_sizes);         }
 183     static int frame_pcs_offset_in_bytes()                 { return offset_of(UnrollBlock, _frame_pcs);                 }
 184     static int register_block_offset_in_bytes()            { return offset_of(UnrollBlock, _register_block);            }
 185     static int return_type_offset_in_bytes()               { return offset_of(UnrollBlock, _return_type);               }
 186     static int counter_temp_offset_in_bytes()              { return offset_of(UnrollBlock, _counter_temp);              }
 187     static int initial_fp_offset_in_bytes()                { return offset_of(UnrollBlock, _initial_fp);                }
 188     static int unpack_kind_offset_in_bytes()               { return offset_of(UnrollBlock, _unpack_kind);               }
 189     static int sender_sp_temp_offset_in_bytes()            { return offset_of(UnrollBlock, _sender_sp_temp);            }
 190 
 191     BasicType return_type() const { return _return_type; }
 192     void print();
 193   };
 194 
 195   //** Returns an UnrollBlock continuing information
 196   // how to make room for the resulting interpreter frames.
 197   // Called by assembly stub after execution has returned to
 198   // deoptimized frame.
 199   // @argument thread.     Thread where stub_frame resides.
 200   // @see OptoRuntime::deoptimization_fetch_unroll_info_C
 201   static UnrollBlock* fetch_unroll_info(JavaThread* thread);
 202 
 203   //** Unpacks vframeArray onto execution stack
 204   // Called by assembly stub after execution has returned to
 205   // deoptimized frame and after the stack unrolling.
 206   // @argument thread.     Thread where stub_frame resides.
 207   // @argument exec_mode.  Determines how execution should be continuted in top frame.
 208   //                       0 means continue after current byte code
 209   //                       1 means exception has happened, handle exception
 210   //                       2 means reexecute current bytecode (for uncommon traps).
 211   // @see OptoRuntime::deoptimization_unpack_frames_C
 212   // Return BasicType of call return type, if any
 213   static BasicType unpack_frames(JavaThread* thread, int exec_mode);
 214 
 215   // Cleans up deoptimization bits on thread after unpacking or in the
 216   // case of an exception.
 217   static void cleanup_deopt_info(JavaThread  *thread,
 218                                  vframeArray * array);
 219 
 220   // Restores callee saved values from deoptimized frame into oldest interpreter frame
 221   // so caller of the deoptimized frame will get back the values it expects.
 222   static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
 223 
 224   //** Performs an uncommon trap for compiled code.
 225   // The top most compiler frame is converted into interpreter frames
 226   static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
 227   // Helper routine that enters the VM and may block
 228   static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);
 229 
 230   //** Deoptimizes the frame identified by id.
 231   // Only called from VMDeoptimizeFrame
 232   // @argument thread.     Thread where stub_frame resides.
 233   // @argument id.         id of frame that should be deoptimized.
 234   static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id);
 235 
 236   // If thread is not the current thread then execute
 237   // VM_DeoptimizeFrame otherwise deoptimize directly.
 238   static void deoptimize_frame(JavaThread* thread, intptr_t* id);
 239 
 240   // Statistics
 241   static void gather_statistics(DeoptReason reason, DeoptAction action,
 242                                 Bytecodes::Code bc = Bytecodes::_illegal);
 243   static void print_statistics();
 244 
 245   // How much room to adjust the last frame's SP by, to make space for
 246   // the callee's interpreter frame (which expects locals to be next to
 247   // incoming arguments)
 248   static int last_frame_adjust(int callee_parameters, int callee_locals);
 249 
 250   // trap_request codes
 251   static DeoptReason trap_request_reason(int trap_request) {
 252     if (trap_request < 0)
 253       return (DeoptReason)
 254         ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
 255     else
 256       // standard reason for unloaded CP entry
 257       return Reason_unloaded;
 258   }
 259   static DeoptAction trap_request_action(int trap_request) {
 260     if (trap_request < 0)
 261       return (DeoptAction)
 262         ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
 263     else
 264       // standard action for unloaded CP entry
 265       return _unloaded_action;
 266   }
 267   static int trap_request_index(int trap_request) {
 268     if (trap_request < 0)
 269       return -1;
 270     else
 271       return trap_request;
 272   }
 273   static int make_trap_request(DeoptReason reason, DeoptAction action,
 274                                int index = -1) {
 275     assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
 276     assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
 277     int trap_request;
 278     if (index != -1)
 279       trap_request = index;
 280     else
 281       trap_request = (~(((reason) << _reason_shift)
 282                         + ((action) << _action_shift)));
 283     assert(reason == trap_request_reason(trap_request), "valid reason");
 284     assert(action == trap_request_action(trap_request), "valid action");
 285     assert(index  == trap_request_index(trap_request),  "valid index");
 286     return trap_request;
 287   }
 288 
 289   // The trap_state stored in a MDO is decoded here.
 290   // It records two items of information.
 291   //  reason:  If a deoptimization happened here, what its reason was,
 292   //           or if there were multiple deopts with differing reasons.
 293   //  recompiled: If a deoptimization here triggered a recompilation.
 294   // Note that not all reasons are recorded per-bci.
 295   static DeoptReason trap_state_reason(int trap_state);
 296   static int  trap_state_has_reason(int trap_state, int reason);
 297   static int  trap_state_add_reason(int trap_state, int reason);
 298   static bool trap_state_is_recompiled(int trap_state);
 299   static int  trap_state_set_recompiled(int trap_state, bool z);
 300   static const char* format_trap_state(char* buf, size_t buflen,
 301                                        int trap_state);
 302 
 303   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
 304     return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
 305   }
 306 
 307   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
 308     if (reason_is_recorded_per_bytecode(reason))
 309       return reason;
 310     else if (reason == Reason_div0_check) // null check due to divide-by-zero?
 311       return Reason_null_check;           // recorded per BCI as a null check
 312     else
 313       return Reason_none;
 314   }
 315 
 316   static const char* trap_reason_name(int reason);
 317   static const char* trap_action_name(int action);
 318   // Format like reason='foo' action='bar' index='123'.
 319   // This is suitable both for XML and for tty output.
 320   static const char* format_trap_request(char* buf, size_t buflen,
 321                                          int trap_request);
 322 
 323   static jint total_deoptimization_count();
 324   static jint deoptimization_count(DeoptReason reason);
 325 
 326   // JVMTI PopFrame support
 327 
 328   // Preserves incoming arguments to the popped frame when it is
 329   // returning to a deoptimized caller
 330   static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
 331 
 332  private:
 333   static methodDataOop get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);
 334   // Update the mdo's count and per-BCI reason bits, returning previous state:
 335   static ProfileData* query_update_method_data(methodDataHandle trap_mdo,
 336                                                int trap_bci,
 337                                                DeoptReason reason,
 338                                                //outputs:
 339                                                uint& ret_this_trap_count,
 340                                                bool& ret_maybe_prior_trap,
 341                                                bool& ret_maybe_prior_recompile);
 342   // class loading support for uncommon trap
 343   static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);
 344   static void load_class_by_index(constantPoolHandle constant_pool, int index);
 345 
 346   static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);
 347 
 348   static DeoptAction _unloaded_action; // == Action_reinterpret;
 349   static const char* _trap_reason_name[Reason_LIMIT];
 350   static const char* _trap_action_name[Action_LIMIT];
 351 
 352   static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
 353   // Note:  Histogram array size is 1-2 Kb.
 354 
 355  public:
 356   static void update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason);
 357 };
 358 
 359 class DeoptimizationMarker : StackObj {  // for profiling
 360   static bool _is_active;
 361 public:
 362   DeoptimizationMarker()  { _is_active = true; }
 363   ~DeoptimizationMarker() { _is_active = false; }
 364   static bool is_active() { return _is_active; }
 365 };
 366 
 367 #endif // SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP