1 /*
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 24 
 25 #ifndef SHARE_RUNTIME_DEOPTIMIZATION_HPP
 26 #define SHARE_RUNTIME_DEOPTIMIZATION_HPP
 27 
 28 #include "interpreter/bytecodes.hpp"
 29 #include "memory/allocation.hpp"
 30 #include "runtime/frame.hpp"
 31 
 32 class ProfileData;
 33 class vframeArray;
 34 class MonitorInfo;
 35 class MonitorValue;
 36 class ObjectValue;
 37 class AutoBoxObjectValue;
 38 class ScopeValue;
 39 class compiledVFrame;
 40 
 41 template<class E> class GrowableArray;
 42 
 43 class DeoptimizationScope {
 44  private:
 45   // What gen we have done the deopt handshake for.
 46   static uint64_t _committed_deopt_gen;
 47   // What gen to mark a method with, hence larger than _committed_deopt_gen.
 48   static uint64_t _active_deopt_gen;
 49   // Indicate an in-progress deopt handshake.
 50   static bool     _committing_in_progress;
 51 
 52   // The required gen we need to execute/wait for
 53   uint64_t _required_gen;
 54   DEBUG_ONLY(bool _deopted;)
 55 
 56  public:
 57   DeoptimizationScope();
 58   ~DeoptimizationScope();
 59   // Mark a method, if already marked as dependent.
 60   void mark(CompiledMethod* cm, bool inc_recompile_counts = true);
 61   // Record this as a dependent method.
 62   void dependent(CompiledMethod* cm);
 63 
 64   // Execute the deoptimization.
 65   // Make the nmethods not entrant, stackwalks and patch return pcs and sets post call nops.
 66   void deoptimize_marked();
 67 };
 68 
 69 class Deoptimization : AllStatic {
 70   friend class VMStructs;
 71   friend class EscapeBarrier;
 72 
 73  public:
 74   // What condition caused the deoptimization?
 75   // Note: Keep this enum in sync. with Deoptimization::_trap_reason_name.
 76   enum DeoptReason {
 77     Reason_many = -1,             // indicates presence of several reasons
 78     Reason_none = 0,              // indicates absence of a relevant deopt.
 79     // Next 8 reasons are recorded per bytecode in DataLayout::trap_bits.
 80     // This is more complicated for JVMCI as JVMCI may deoptimize to *some* bytecode before the
 81     // bytecode that actually caused the deopt (with inlining, JVMCI may even deoptimize to a
 82     // bytecode in another method):
 83     //  - bytecode y in method b() causes deopt
 84     //  - JVMCI deoptimizes to bytecode x in method a()
 85     // -> the deopt reason will be recorded for method a() at bytecode x
 86     Reason_null_check,            // saw unexpected null or zero divisor (@bci)
 87     Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)
 88     Reason_range_check,           // saw unexpected array index (@bci)
 89     Reason_class_check,           // saw unexpected object class (@bci)
 90     Reason_array_check,           // saw unexpected array class (aastore @bci)
 91     Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)
 92     Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)
 93 
 94 #if INCLUDE_JVMCI
 95     Reason_unreached0             = Reason_null_assert,
 96     Reason_type_checked_inlining  = Reason_intrinsic,
 97     Reason_optimized_type_check   = Reason_bimorphic,
 98 #endif
 99 
100     Reason_profile_predicate,     // compiler generated predicate moved from frequent branch in a loop failed
101 
102     // recorded per method
103     Reason_unloaded,              // unloaded class or constant pool entry
104     Reason_uninitialized,         // bad class state (uninitialized)
105     Reason_initialized,           // class has been fully initialized
106     Reason_unreached,             // code is not reached, compiler
107     Reason_unhandled,             // arbitrary compiler limitation
108     Reason_constraint,            // arbitrary runtime constraint violated
109     Reason_div0_check,            // a null_check due to division by zero
110     Reason_age,                   // nmethod too old; tier threshold reached
111     Reason_predicate,             // compiler generated predicate failed
112     Reason_loop_limit_check,      // compiler generated loop limits check failed
113     Reason_speculate_class_check, // saw unexpected object class from type speculation
114     Reason_speculate_null_check,  // saw unexpected null from type speculation
115     Reason_speculate_null_assert, // saw unexpected null from type speculation
116     Reason_rtm_state_change,      // rtm state change detected
117     Reason_unstable_if,           // a branch predicted always false was taken
118     Reason_unstable_fused_if,     // fused two ifs that had each one untaken branch. One is now taken.
119     Reason_receiver_constraint,   // receiver subtype check failed
120 #if INCLUDE_JVMCI
121     Reason_aliasing,              // optimistic assumption about aliasing failed
122     Reason_transfer_to_interpreter, // explicit transferToInterpreter()
123     Reason_not_compiled_exception_handler,
124     Reason_unresolved,
125     Reason_jsr_mismatch,
126 #endif
127 
128     // Used to define MethodData::_trap_hist_limit where Reason_tenured isn't included
129     Reason_TRAP_HISTORY_LENGTH,
130 
131     // Reason_tenured is counted separately, add normal counted Reasons above.
132     Reason_tenured = Reason_TRAP_HISTORY_LENGTH, // age of the code has reached the limit
133     Reason_LIMIT,
134 
135     // Note:  Reason_RECORDED_LIMIT should fit into 31 bits of
136     // DataLayout::trap_bits.  This dependency is enforced indirectly
137     // via asserts, to avoid excessive direct header-to-header dependencies.
138     // See Deoptimization::trap_state_reason and class DataLayout.
139     Reason_RECORDED_LIMIT = Reason_profile_predicate,  // some are not recorded per bc
140   };
141 
142   // What action must be taken by the runtime?
143   // Note: Keep this enum in sync. with Deoptimization::_trap_action_name.
144   enum DeoptAction {
145     Action_none,                  // just interpret, do not invalidate nmethod
146     Action_maybe_recompile,       // recompile the nmethod; need not invalidate
147     Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile
148     Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)
149     Action_make_not_compilable,   // invalidate the nmethod and do not compile
150     Action_LIMIT
151   };
152 
153   enum {
154     _action_bits = 3,
155     _reason_bits = 5,
156     _debug_id_bits = 23,
157     _action_shift = 0,
158     _reason_shift = _action_shift+_action_bits,
159     _debug_id_shift = _reason_shift+_reason_bits,
160     BC_CASE_LIMIT = 4 // for _deoptimization_hist
161   };
162 
163   enum UnpackType {
164     Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
165     Unpack_exception            = 1, // exception is pending
166     Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)
167     Unpack_reexecute            = 3, // reexecute bytecode (C1 only)
168     Unpack_none                 = 4, // not deoptimizing the frame, just reallocating/relocking for JVMTI
169     Unpack_LIMIT                = 5
170   };
171 
172 #if INCLUDE_JVMCI
173   // Can reconstruct virtualized unsafe large accesses to byte arrays.
174   static const int _support_large_access_byte_array_virtualization = 1;
175 #endif
176 
177   // Make all nmethods that are marked_for_deoptimization not_entrant and deoptimize any live
178   // activations using those nmethods. Scan of the code cache is done to
179   // find all marked nmethods and they are made not_entrant.
180   static void deoptimize_all_marked();
181 
182  public:
183   // Deoptimizes a frame lazily. Deopt happens on return to the frame.
184   static void deoptimize(JavaThread* thread, frame fr, DeoptReason reason = Reason_constraint);
185 
186 #if INCLUDE_JVMCI
187   static address deoptimize_for_missing_exception_handler(CompiledMethod* cm);
188   static oop get_cached_box(AutoBoxObjectValue* bv, frame* fr, RegisterMap* reg_map, bool& cache_init_error, TRAPS);
189 #endif
190 
191   private:
192   // Does the actual work for deoptimizing a single frame
193   static void deoptimize_single_frame(JavaThread* thread, frame fr, DeoptReason reason);
194 
195 #if COMPILER2_OR_JVMCI
196   // Deoptimize objects, that is reallocate and relock them, just before they
197   // escape through JVMTI.  The given vframes cover one physical frame.
198   static bool deoptimize_objects_internal(JavaThread* thread, GrowableArray<compiledVFrame*>* chunk,
199                                           bool& realloc_failures);
200 
201  public:
202 
203   // Support for restoring non-escaping objects
204   static bool realloc_objects(JavaThread* thread, frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, TRAPS);
205   static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
206   static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
207   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, bool realloc_failures, bool skip_internal);
208   static bool relock_objects(JavaThread* thread, GrowableArray<MonitorInfo*>* monitors,
209                              JavaThread* deoptee_thread, frame& fr, int exec_mode, bool realloc_failures);
210   static void pop_frames_failed_reallocs(JavaThread* thread, vframeArray* array);
211 #endif // COMPILER2_OR_JVMCI
212 
213   public:
214   static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk, bool realloc_failures);
215 
216   // Interface used for unpacking deoptimized frames
217 
218   // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
219   // This is only a CheapObj to ease debugging after a deopt failure
220   class UnrollBlock : public CHeapObj<mtCompiler> {
221     friend class VMStructs;
222     friend class JVMCIVMStructs;
223    private:
224     int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
225     int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame
226     int       _number_of_frames;          // Number frames to unroll
227     int       _total_frame_sizes;         // Total of number*sizes frames
228     intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack
229     address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack
230     intptr_t* _register_block;            // Block for storing callee-saved registers.
231     BasicType _return_type;               // Tells if we have to restore double or long return value
232     intptr_t  _initial_info;              // Platform dependent data for the sender frame (was FP on x86)
233     int       _caller_actual_parameters;  // The number of actual arguments at the
234                                           // interpreted caller of the deoptimized frame
235     int       _unpack_kind;               // exec_mode that can be changed during fetch_unroll_info
236 
237     // The following fields are used as temps during the unpacking phase
238     // (which is tight on registers, especially on x86). They really ought
239     // to be PD variables but that involves moving this class into its own
240     // file to use the pd include mechanism. Maybe in a later cleanup ...
241     intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)
242     intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)
243    public:
244     // Constructor
245     UnrollBlock(int  size_of_deoptimized_frame,
246                 int  caller_adjustment,
247                 int  caller_actual_parameters,
248                 int  number_of_frames,
249                 intptr_t* frame_sizes,
250                 address* frames_pcs,
251                 BasicType return_type,
252                 int unpack_kind);
253     ~UnrollBlock();
254 
255     // Accessors
256     intptr_t* frame_sizes()  const { return _frame_sizes; }
257     int number_of_frames()  const { return _number_of_frames; }
258 
259     // Returns the total size of frames
260     int size_of_frames() const;
261 
262     void set_initial_info(intptr_t info) { _initial_info = info; }
263 
264     int caller_actual_parameters() const { return _caller_actual_parameters; }
265 
266     // Accessors used by the code generator for the unpack stub.
267     static ByteSize size_of_deoptimized_frame_offset() { return byte_offset_of(UnrollBlock, _size_of_deoptimized_frame); }
268     static ByteSize caller_adjustment_offset()         { return byte_offset_of(UnrollBlock, _caller_adjustment);         }
269     static ByteSize number_of_frames_offset()          { return byte_offset_of(UnrollBlock, _number_of_frames);          }
270     static ByteSize frame_sizes_offset()               { return byte_offset_of(UnrollBlock, _frame_sizes);               }
271     static ByteSize total_frame_sizes_offset()         { return byte_offset_of(UnrollBlock, _total_frame_sizes);         }
272     static ByteSize frame_pcs_offset()                 { return byte_offset_of(UnrollBlock, _frame_pcs);                 }
273     static ByteSize counter_temp_offset()              { return byte_offset_of(UnrollBlock, _counter_temp);              }
274     static ByteSize initial_info_offset()              { return byte_offset_of(UnrollBlock, _initial_info);              }
275     static ByteSize unpack_kind_offset()               { return byte_offset_of(UnrollBlock, _unpack_kind);               }
276     static ByteSize sender_sp_temp_offset()            { return byte_offset_of(UnrollBlock, _sender_sp_temp);            }
277 
278     BasicType return_type() const { return _return_type; }
279     void print();
280   };
281 
282   //** Returns an UnrollBlock continuing information
283   // how to make room for the resulting interpreter frames.
284   // Called by assembly stub after execution has returned to
285   // deoptimized frame.
286   // @argument thread.     Thread where stub_frame resides.
287   // @see OptoRuntime::deoptimization_fetch_unroll_info_C
288   static UnrollBlock* fetch_unroll_info(JavaThread* current, int exec_mode);
289 
290   //** Unpacks vframeArray onto execution stack
291   // Called by assembly stub after execution has returned to
292   // deoptimized frame and after the stack unrolling.
293   // @argument thread.     Thread where stub_frame resides.
294   // @argument exec_mode.  Determines how execution should be continued in top frame.
295   //                       0 means continue after current byte code
296   //                       1 means exception has happened, handle exception
297   //                       2 means reexecute current bytecode (for uncommon traps).
298   // @see OptoRuntime::deoptimization_unpack_frames_C
299   // Return BasicType of call return type, if any
300   static BasicType unpack_frames(JavaThread* thread, int exec_mode);
301 
302   // Cleans up deoptimization bits on thread after unpacking or in the
303   // case of an exception.
304   static void cleanup_deopt_info(JavaThread  *thread,
305                                  vframeArray * array);
306 
307   // Restores callee saved values from deoptimized frame into oldest interpreter frame
308   // so caller of the deoptimized frame will get back the values it expects.
309   static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
310 
311   //** Performs an uncommon trap for compiled code.
312   // The top most compiler frame is converted into interpreter frames
313   static UnrollBlock* uncommon_trap(JavaThread* current, jint unloaded_class_index, jint exec_mode);
314   // Helper routine that enters the VM and may block
315   static void uncommon_trap_inner(JavaThread* current, jint unloaded_class_index);
316 
317   //** Deoptimizes the frame identified by id.
318   // Only called from VMDeoptimizeFrame
319   // @argument thread.     Thread where stub_frame resides.
320   // @argument id.         id of frame that should be deoptimized.
321   static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id, DeoptReason reason);
322 
323   // if thread is not the current thread then execute
324   // VM_DeoptimizeFrame otherwise deoptimize directly.
325   static void deoptimize_frame(JavaThread* thread, intptr_t* id, DeoptReason reason);
326   static void deoptimize_frame(JavaThread* thread, intptr_t* id);
327 
328   // Statistics
329   static void gather_statistics(DeoptReason reason, DeoptAction action,
330                                 Bytecodes::Code bc = Bytecodes::_illegal);
331   static void print_statistics();
332   static void print_statistics_on(outputStream* st);
333 
334   // How much room to adjust the last frame's SP by, to make space for
335   // the callee's interpreter frame (which expects locals to be next to
336   // incoming arguments)
337   static int last_frame_adjust(int callee_parameters, int callee_locals);
338 
339   // trap_request codes
340   static DeoptReason trap_request_reason(int trap_request) {
341     if (trap_request < 0)
342       return (DeoptReason)
343         ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
344     else
345       // standard reason for unloaded CP entry
346       return Reason_unloaded;
347   }
348   static DeoptAction trap_request_action(int trap_request) {
349     if (trap_request < 0)
350       return (DeoptAction)
351         ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
352     else
353       // standard action for unloaded CP entry
354       return _unloaded_action;
355   }
356   static int trap_request_debug_id(int trap_request) {
357     if (trap_request < 0) {
358       return ((~(trap_request) >> _debug_id_shift) & right_n_bits(_debug_id_bits));
359     } else {
360       // standard action for unloaded CP entry
361       return 0;
362     }
363   }
364   static int trap_request_index(int trap_request) {
365     if (trap_request < 0)
366       return -1;
367     else
368       return trap_request;
369   }
370   static int make_trap_request(DeoptReason reason, DeoptAction action,
371                                int index = -1) {
372     assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
373     assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
374     int trap_request;
375     if (index != -1)
376       trap_request = index;
377     else
378       trap_request = (~(((reason) << _reason_shift)
379                         + ((action) << _action_shift)));
380     assert(reason == trap_request_reason(trap_request), "valid reason");
381     assert(action == trap_request_action(trap_request), "valid action");
382     assert(index  == trap_request_index(trap_request),  "valid index");
383     return trap_request;
384   }
385 
386   // The trap_state stored in a MDO is decoded here.
387   // It records two items of information.
388   //  reason:  If a deoptimization happened here, what its reason was,
389   //           or if there were multiple deopts with differing reasons.
390   //  recompiled: If a deoptimization here triggered a recompilation.
391   // Note that not all reasons are recorded per-bci.
392   static DeoptReason trap_state_reason(int trap_state);
393   static int  trap_state_has_reason(int trap_state, int reason);
394   static int  trap_state_add_reason(int trap_state, int reason);
395   static bool trap_state_is_recompiled(int trap_state);
396   static int  trap_state_set_recompiled(int trap_state, bool z);
397   static const char* format_trap_state(char* buf, size_t buflen,
398                                        int trap_state);
399 
400   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
401     return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
402   }
403 
404   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
405     if (reason_is_recorded_per_bytecode(reason))
406       return reason;
407     else if (reason == Reason_div0_check) // null check due to divide-by-zero?
408       return Reason_null_check;           // recorded per BCI as a null check
409     else if (reason == Reason_speculate_class_check)
410       return Reason_class_check;
411     else if (reason == Reason_speculate_null_check)
412       return Reason_null_check;
413     else if (reason == Reason_speculate_null_assert)
414       return Reason_null_assert;
415     else if (reason == Reason_unstable_if)
416       return Reason_intrinsic;
417     else if (reason == Reason_unstable_fused_if)
418       return Reason_range_check;
419     else
420       return Reason_none;
421   }
422 
423   static bool reason_is_speculate(int reason) {
424     if (reason == Reason_speculate_class_check ||
425         reason == Reason_speculate_null_check ||
426         reason == Reason_speculate_null_assert) {
427       return true;
428     }
429     return false;
430   }
431 
432   static DeoptReason reason_null_check(bool speculative) {
433     return speculative ? Deoptimization::Reason_speculate_null_check : Deoptimization::Reason_null_check;
434   }
435 
436   static DeoptReason reason_class_check(bool speculative) {
437     return speculative ? Deoptimization::Reason_speculate_class_check : Deoptimization::Reason_class_check;
438   }
439 
440   static DeoptReason reason_null_assert(bool speculative) {
441     return speculative ? Deoptimization::Reason_speculate_null_assert : Deoptimization::Reason_null_assert;
442   }
443 
444   static uint per_method_trap_limit(int reason) {
445     return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;
446   }
447 
448   static const char* trap_reason_name(int reason);
449   static const char* trap_action_name(int action);
450   // Format like reason='foo' action='bar' index='123'.
451   // This is suitable both for XML and for tty output.
452   static const char* format_trap_request(char* buf, size_t buflen,
453                                          int trap_request);
454 
455   static jint total_deoptimization_count();
456   static jint deoptimization_count(const char* reason_str, const char* action_str);
457 
458   // JVMTI PopFrame support
459 
460   // Preserves incoming arguments to the popped frame when it is
461   // returning to a deoptimized caller
462   static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
463 
464   static MethodData* get_method_data(JavaThread* thread, const methodHandle& m, bool create_if_missing);
465  private:
466   // Update the mdo's count and per-BCI reason bits, returning previous state:
467   static ProfileData* query_update_method_data(MethodData* trap_mdo,
468                                                int trap_bci,
469                                                DeoptReason reason,
470                                                bool update_total_trap_count,
471 #if INCLUDE_JVMCI
472                                                bool is_osr,
473 #endif
474                                                Method* compiled_method,
475                                                //outputs:
476                                                uint& ret_this_trap_count,
477                                                bool& ret_maybe_prior_trap,
478                                                bool& ret_maybe_prior_recompile);
479   // class loading support for uncommon trap
480   static void load_class_by_index(const constantPoolHandle& constant_pool, int index, TRAPS);
481 
482   static UnrollBlock* fetch_unroll_info_helper(JavaThread* current, int exec_mode);
483 
484   static DeoptAction _unloaded_action; // == Action_reinterpret;
485   static const char* _trap_reason_name[];
486   static const char* _trap_action_name[];
487 
488   static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
489   // Note:  Histogram array size is 1-2 Kb.
490 
491  public:
492   static void update_method_data_from_interpreter(MethodData* trap_mdo, int trap_bci, int reason);
493 
494   static void init_counters();
495   static void print_counters_on(outputStream* st);
496 };
497 
498 #endif // SHARE_RUNTIME_DEOPTIMIZATION_HPP