1 /*
  2  * Copyright (c) 1997, 2021, 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_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 Deoptimization : AllStatic {
 44   friend class VMStructs;
 45   friend class EscapeBarrier;
 46 
 47  public:
 48   // What condition caused the deoptimization?
 49   // Note: Keep this enum in sync. with Deoptimization::_trap_reason_name.
 50   enum DeoptReason {
 51     Reason_many = -1,             // indicates presence of several reasons
 52     Reason_none = 0,              // indicates absence of a relevant deopt.
 53     // Next 8 reasons are recorded per bytecode in DataLayout::trap_bits.
 54     // This is more complicated for JVMCI as JVMCI may deoptimize to *some* bytecode before the
 55     // bytecode that actually caused the deopt (with inlining, JVMCI may even deoptimize to a
 56     // bytecode in another method):
 57     //  - bytecode y in method b() causes deopt
 58     //  - JVMCI deoptimizes to bytecode x in method a()
 59     // -> the deopt reason will be recorded for method a() at bytecode x
 60     Reason_null_check,            // saw unexpected null or zero divisor (@bci)
 61     Reason_null_assert,           // saw unexpected non-null or non-zero (@bci)
 62     Reason_range_check,           // saw unexpected array index (@bci)
 63     Reason_class_check,           // saw unexpected object class (@bci)
 64     Reason_array_check,           // saw unexpected array class (aastore @bci)
 65     Reason_intrinsic,             // saw unexpected operand to intrinsic (@bci)
 66     Reason_bimorphic,             // saw unexpected object class in bimorphic inlining (@bci)
 67 
 68 #if INCLUDE_JVMCI
 69     Reason_unreached0             = Reason_null_assert,
 70     Reason_type_checked_inlining  = Reason_intrinsic,
 71     Reason_optimized_type_check   = Reason_bimorphic,
 72 #endif
 73 
 74     Reason_profile_predicate,     // compiler generated predicate moved from frequent branch in a loop failed
 75 
 76     // recorded per method
 77     Reason_unloaded,              // unloaded class or constant pool entry
 78     Reason_uninitialized,         // bad class state (uninitialized)
 79     Reason_initialized,           // class has been fully initialized
 80     Reason_unreached,             // code is not reached, compiler
 81     Reason_unhandled,             // arbitrary compiler limitation
 82     Reason_constraint,            // arbitrary runtime constraint violated
 83     Reason_div0_check,            // a null_check due to division by zero
 84     Reason_age,                   // nmethod too old; tier threshold reached
 85     Reason_predicate,             // compiler generated predicate failed
 86     Reason_loop_limit_check,      // compiler generated loop limits check failed
 87     Reason_speculate_class_check, // saw unexpected object class from type speculation
 88     Reason_speculate_null_check,  // saw unexpected null from type speculation
 89     Reason_speculate_null_assert, // saw unexpected null from type speculation
 90     Reason_rtm_state_change,      // rtm state change detected
 91     Reason_unstable_if,           // a branch predicted always false was taken
 92     Reason_unstable_fused_if,     // fused two ifs that had each one untaken branch. One is now taken.
 93     Reason_receiver_constraint,   // receiver subtype check failed
 94 #if INCLUDE_JVMCI
 95     Reason_aliasing,              // optimistic assumption about aliasing failed
 96     Reason_transfer_to_interpreter, // explicit transferToInterpreter()
 97     Reason_not_compiled_exception_handler,
 98     Reason_unresolved,
 99     Reason_jsr_mismatch,
100 #endif
101 
102     // Used to define MethodData::_trap_hist_limit where Reason_tenured isn't included
103     Reason_TRAP_HISTORY_LENGTH,
104 
105     // Reason_tenured is counted separately, add normal counted Reasons above.
106     Reason_tenured = Reason_TRAP_HISTORY_LENGTH, // age of the code has reached the limit
107     Reason_LIMIT,
108 
109     // Note:  Reason_RECORDED_LIMIT should fit into 31 bits of
110     // DataLayout::trap_bits.  This dependency is enforced indirectly
111     // via asserts, to avoid excessive direct header-to-header dependencies.
112     // See Deoptimization::trap_state_reason and class DataLayout.
113     Reason_RECORDED_LIMIT = Reason_profile_predicate,  // some are not recorded per bc
114   };
115 
116   // What action must be taken by the runtime?
117   // Note: Keep this enum in sync. with Deoptimization::_trap_action_name.
118   enum DeoptAction {
119     Action_none,                  // just interpret, do not invalidate nmethod
120     Action_maybe_recompile,       // recompile the nmethod; need not invalidate
121     Action_reinterpret,           // invalidate the nmethod, reset IC, maybe recompile
122     Action_make_not_entrant,      // invalidate the nmethod, recompile (probably)
123     Action_make_not_compilable,   // invalidate the nmethod and do not compile
124     Action_LIMIT
125   };
126 
127   enum {
128     _action_bits = 3,
129     _reason_bits = 5,
130     _debug_id_bits = 23,
131     _action_shift = 0,
132     _reason_shift = _action_shift+_action_bits,
133     _debug_id_shift = _reason_shift+_reason_bits,
134     BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
135   };
136 
137   enum UnpackType {
138     Unpack_deopt                = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
139     Unpack_exception            = 1, // exception is pending
140     Unpack_uncommon_trap        = 2, // redo last byte code (C2 only)
141     Unpack_reexecute            = 3, // reexecute bytecode (C1 only)
142     Unpack_none                 = 4, // not deoptimizing the frame, just reallocating/relocking for JVMTI
143     Unpack_LIMIT                = 5
144   };
145 
146 #if INCLUDE_JVMCI
147   // Can reconstruct virtualized unsafe large accesses to byte arrays.
148   static const int _support_large_access_byte_array_virtualization = 1;
149 #endif
150 
151   // Make all nmethods that are marked_for_deoptimization not_entrant and deoptimize any live
152   // activations using those nmethods.  If an nmethod is passed as an argument then it is
153   // marked_for_deoptimization and made not_entrant.  Otherwise a scan of the code cache is done to
154   // find all marked nmethods and they are made not_entrant.
155   static void deoptimize_all_marked(nmethod* nmethod_only = NULL);
156 
157  public:
158   // Deoptimizes a frame lazily. Deopt happens on return to the frame.
159   static void deoptimize(JavaThread* thread, frame fr, DeoptReason reason = Reason_constraint);
160 
161 #if INCLUDE_JVMCI
162   static address deoptimize_for_missing_exception_handler(CompiledMethod* cm);
163 #endif
164 
165   static oop get_cached_box(AutoBoxObjectValue* bv, frame* fr, RegisterMap* reg_map, TRAPS);
166 
167   private:
168   // Does the actual work for deoptimizing a single frame
169   static void deoptimize_single_frame(JavaThread* thread, frame fr, DeoptReason reason);
170 
171 #if COMPILER2_OR_JVMCI
172   // Deoptimize objects, that is reallocate and relock them, just before they
173   // escape through JVMTI.  The given vframes cover one physical frame.
174   static bool deoptimize_objects_internal(JavaThread* thread, GrowableArray<compiledVFrame*>* chunk,
175                                           bool& realloc_failures);
176 
177  public:
178 
179   // Support for restoring non-escaping objects
180   static bool realloc_objects(JavaThread* thread, frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, TRAPS);
181   static bool realloc_inline_type_result(InlineKlass* vk, const RegisterMap& map, GrowableArray<Handle>& return_oops, TRAPS);
182   static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
183   static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
184   static void reassign_flat_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, flatArrayOop obj, FlatArrayKlass* vak, bool skip_internal, TRAPS);
185   static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects, bool realloc_failures, bool skip_internal, TRAPS);
186   static bool relock_objects(JavaThread* thread, GrowableArray<MonitorInfo*>* monitors,
187                              JavaThread* deoptee_thread, frame& fr, int exec_mode, bool realloc_failures);
188   static void pop_frames_failed_reallocs(JavaThread* thread, vframeArray* array);
189 #endif // COMPILER2_OR_JVMCI
190 
191   public:
192   static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk, bool realloc_failures);
193 
194   // Interface used for unpacking deoptimized frames
195 
196   // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
197   // This is only a CheapObj to ease debugging after a deopt failure
198   class UnrollBlock : public CHeapObj<mtCompiler> {
199     friend class VMStructs;
200     friend class JVMCIVMStructs;
201    private:
202     int       _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
203     int       _caller_adjustment;         // Adjustment, in bytes, to caller's SP by initial interpreted frame
204     int       _number_of_frames;          // Number frames to unroll
205     int       _total_frame_sizes;         // Total of number*sizes frames
206     intptr_t* _frame_sizes;               // Array of frame sizes, in bytes, for unrolling the stack
207     address*  _frame_pcs;                 // Array of frame pc's, in bytes, for unrolling the stack
208     intptr_t* _register_block;            // Block for storing callee-saved registers.
209     BasicType _return_type;               // Tells if we have to restore double or long return value
210     intptr_t  _initial_info;              // Platform dependent data for the sender frame (was FP on x86)
211     int       _caller_actual_parameters;  // The number of actual arguments at the
212                                           // interpreted caller of the deoptimized frame
213     int       _unpack_kind;               // exec_mode that can be changed during fetch_unroll_info
214 
215     // The following fields are used as temps during the unpacking phase
216     // (which is tight on registers, especially on x86). They really ought
217     // to be PD variables but that involves moving this class into its own
218     // file to use the pd include mechanism. Maybe in a later cleanup ...
219     intptr_t  _counter_temp;              // SHOULD BE PD VARIABLE (x86 frame count temp)
220     intptr_t  _sender_sp_temp;            // SHOULD BE PD VARIABLE (x86 sender_sp)
221    public:
222     // Constructor
223     UnrollBlock(int  size_of_deoptimized_frame,
224                 int  caller_adjustment,
225                 int  caller_actual_parameters,
226                 int  number_of_frames,
227                 intptr_t* frame_sizes,
228                 address* frames_pcs,
229                 BasicType return_type,
230                 int unpack_kind);
231     ~UnrollBlock();
232 
233     // Returns where a register is located.
234     intptr_t* value_addr_at(int register_number) const;
235 
236     // Accessors
237     intptr_t* frame_sizes()  const { return _frame_sizes; }
238     int number_of_frames()  const { return _number_of_frames; }
239     address*  frame_pcs()   const { return _frame_pcs ; }
240     int  unpack_kind()   const { return _unpack_kind; }
241 
242     // Returns the total size of frames
243     int size_of_frames() const;
244 
245     void set_initial_info(intptr_t info) { _initial_info = info; }
246 
247     int caller_actual_parameters() const { return _caller_actual_parameters; }
248 
249     // Accessors used by the code generator for the unpack stub.
250     static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
251     static int caller_adjustment_offset_in_bytes()         { return offset_of(UnrollBlock, _caller_adjustment);         }
252     static int number_of_frames_offset_in_bytes()          { return offset_of(UnrollBlock, _number_of_frames);          }
253     static int frame_sizes_offset_in_bytes()               { return offset_of(UnrollBlock, _frame_sizes);               }
254     static int total_frame_sizes_offset_in_bytes()         { return offset_of(UnrollBlock, _total_frame_sizes);         }
255     static int frame_pcs_offset_in_bytes()                 { return offset_of(UnrollBlock, _frame_pcs);                 }
256     static int register_block_offset_in_bytes()            { return offset_of(UnrollBlock, _register_block);            }
257     static int return_type_offset_in_bytes()               { return offset_of(UnrollBlock, _return_type);               }
258     static int counter_temp_offset_in_bytes()              { return offset_of(UnrollBlock, _counter_temp);              }
259     static int initial_info_offset_in_bytes()              { return offset_of(UnrollBlock, _initial_info);              }
260     static int unpack_kind_offset_in_bytes()               { return offset_of(UnrollBlock, _unpack_kind);               }
261     static int sender_sp_temp_offset_in_bytes()            { return offset_of(UnrollBlock, _sender_sp_temp);            }
262 
263     BasicType return_type() const { return _return_type; }
264     void print();
265   };
266 
267   //** Returns an UnrollBlock continuing information
268   // how to make room for the resulting interpreter frames.
269   // Called by assembly stub after execution has returned to
270   // deoptimized frame.
271   // @argument thread.     Thread where stub_frame resides.
272   // @see OptoRuntime::deoptimization_fetch_unroll_info_C
273   static UnrollBlock* fetch_unroll_info(JavaThread* current, int exec_mode);
274 
275   //** Unpacks vframeArray onto execution stack
276   // Called by assembly stub after execution has returned to
277   // deoptimized frame and after the stack unrolling.
278   // @argument thread.     Thread where stub_frame resides.
279   // @argument exec_mode.  Determines how execution should be continued in top frame.
280   //                       0 means continue after current byte code
281   //                       1 means exception has happened, handle exception
282   //                       2 means reexecute current bytecode (for uncommon traps).
283   // @see OptoRuntime::deoptimization_unpack_frames_C
284   // Return BasicType of call return type, if any
285   static BasicType unpack_frames(JavaThread* thread, int exec_mode);
286 
287   // Cleans up deoptimization bits on thread after unpacking or in the
288   // case of an exception.
289   static void cleanup_deopt_info(JavaThread  *thread,
290                                  vframeArray * array);
291 
292   // Restores callee saved values from deoptimized frame into oldest interpreter frame
293   // so caller of the deoptimized frame will get back the values it expects.
294   static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
295 
296   //** Performs an uncommon trap for compiled code.
297   // The top most compiler frame is converted into interpreter frames
298   static UnrollBlock* uncommon_trap(JavaThread* current, jint unloaded_class_index, jint exec_mode);
299   // Helper routine that enters the VM and may block
300   static void uncommon_trap_inner(JavaThread* current, jint unloaded_class_index);
301 
302   //** Deoptimizes the frame identified by id.
303   // Only called from VMDeoptimizeFrame
304   // @argument thread.     Thread where stub_frame resides.
305   // @argument id.         id of frame that should be deoptimized.
306   static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id, DeoptReason reason);
307 
308   // if thread is not the current thread then execute
309   // VM_DeoptimizeFrame otherwise deoptimize directly.
310   static void deoptimize_frame(JavaThread* thread, intptr_t* id, DeoptReason reason);
311   static void deoptimize_frame(JavaThread* thread, intptr_t* id);
312 
313   // Statistics
314   static void gather_statistics(DeoptReason reason, DeoptAction action,
315                                 Bytecodes::Code bc = Bytecodes::_illegal);
316   static void print_statistics();
317 
318   // How much room to adjust the last frame's SP by, to make space for
319   // the callee's interpreter frame (which expects locals to be next to
320   // incoming arguments)
321   static int last_frame_adjust(int callee_parameters, int callee_locals);
322 
323   // trap_request codes
324   static DeoptReason trap_request_reason(int trap_request) {
325     if (trap_request < 0)
326       return (DeoptReason)
327         ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
328     else
329       // standard reason for unloaded CP entry
330       return Reason_unloaded;
331   }
332   static DeoptAction trap_request_action(int trap_request) {
333     if (trap_request < 0)
334       return (DeoptAction)
335         ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
336     else
337       // standard action for unloaded CP entry
338       return _unloaded_action;
339   }
340   static int trap_request_debug_id(int trap_request) {
341     if (trap_request < 0) {
342       return ((~(trap_request) >> _debug_id_shift) & right_n_bits(_debug_id_bits));
343     } else {
344       // standard action for unloaded CP entry
345       return 0;
346     }
347   }
348   static int trap_request_index(int trap_request) {
349     if (trap_request < 0)
350       return -1;
351     else
352       return trap_request;
353   }
354   static int make_trap_request(DeoptReason reason, DeoptAction action,
355                                int index = -1) {
356     assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
357     assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
358     int trap_request;
359     if (index != -1)
360       trap_request = index;
361     else
362       trap_request = (~(((reason) << _reason_shift)
363                         + ((action) << _action_shift)));
364     assert(reason == trap_request_reason(trap_request), "valid reason");
365     assert(action == trap_request_action(trap_request), "valid action");
366     assert(index  == trap_request_index(trap_request),  "valid index");
367     return trap_request;
368   }
369 
370   // The trap_state stored in a MDO is decoded here.
371   // It records two items of information.
372   //  reason:  If a deoptimization happened here, what its reason was,
373   //           or if there were multiple deopts with differing reasons.
374   //  recompiled: If a deoptimization here triggered a recompilation.
375   // Note that not all reasons are recorded per-bci.
376   static DeoptReason trap_state_reason(int trap_state);
377   static int  trap_state_has_reason(int trap_state, int reason);
378   static int  trap_state_add_reason(int trap_state, int reason);
379   static bool trap_state_is_recompiled(int trap_state);
380   static int  trap_state_set_recompiled(int trap_state, bool z);
381   static const char* format_trap_state(char* buf, size_t buflen,
382                                        int trap_state);
383 
384   static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
385     return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
386   }
387 
388   static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
389     if (reason_is_recorded_per_bytecode(reason))
390       return reason;
391     else if (reason == Reason_div0_check) // null check due to divide-by-zero?
392       return Reason_null_check;           // recorded per BCI as a null check
393     else if (reason == Reason_speculate_class_check)
394       return Reason_class_check;
395     else if (reason == Reason_speculate_null_check)
396       return Reason_null_check;
397     else if (reason == Reason_speculate_null_assert)
398       return Reason_null_assert;
399     else if (reason == Reason_unstable_if)
400       return Reason_intrinsic;
401     else if (reason == Reason_unstable_fused_if)
402       return Reason_range_check;
403     else
404       return Reason_none;
405   }
406 
407   static bool reason_is_speculate(int reason) {
408     if (reason == Reason_speculate_class_check ||
409         reason == Reason_speculate_null_check ||
410         reason == Reason_speculate_null_assert) {
411       return true;
412     }
413     return false;
414   }
415 
416   static DeoptReason reason_null_check(bool speculative) {
417     return speculative ? Deoptimization::Reason_speculate_null_check : Deoptimization::Reason_null_check;
418   }
419 
420   static DeoptReason reason_class_check(bool speculative) {
421     return speculative ? Deoptimization::Reason_speculate_class_check : Deoptimization::Reason_class_check;
422   }
423 
424   static DeoptReason reason_null_assert(bool speculative) {
425     return speculative ? Deoptimization::Reason_speculate_null_assert : Deoptimization::Reason_null_assert;
426   }
427 
428   static uint per_method_trap_limit(int reason) {
429     return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;
430   }
431 
432   static const char* trap_reason_name(int reason);
433   static const char* trap_action_name(int action);
434   // Format like reason='foo' action='bar' index='123'.
435   // This is suitable both for XML and for tty output.
436   static const char* format_trap_request(char* buf, size_t buflen,
437                                          int trap_request);
438 
439   static jint total_deoptimization_count();
440   static jint deoptimization_count(const char* reason_str, const char* action_str);
441 
442   // JVMTI PopFrame support
443 
444   // Preserves incoming arguments to the popped frame when it is
445   // returning to a deoptimized caller
446   static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
447 
448   static MethodData* get_method_data(JavaThread* thread, const methodHandle& m, bool create_if_missing);
449  private:
450   // Update the mdo's count and per-BCI reason bits, returning previous state:
451   static ProfileData* query_update_method_data(MethodData* trap_mdo,
452                                                int trap_bci,
453                                                DeoptReason reason,
454                                                bool update_total_trap_count,
455 #if INCLUDE_JVMCI
456                                                bool is_osr,
457 #endif
458                                                Method* compiled_method,
459                                                //outputs:
460                                                uint& ret_this_trap_count,
461                                                bool& ret_maybe_prior_trap,
462                                                bool& ret_maybe_prior_recompile);
463   // class loading support for uncommon trap
464   static void load_class_by_index(const constantPoolHandle& constant_pool, int index, TRAPS);
465 
466   static UnrollBlock* fetch_unroll_info_helper(JavaThread* current, int exec_mode);
467 
468   static DeoptAction _unloaded_action; // == Action_reinterpret;
469   static const char* _trap_reason_name[];
470   static const char* _trap_action_name[];
471 
472   static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
473   // Note:  Histogram array size is 1-2 Kb.
474 
475  public:
476   static void update_method_data_from_interpreter(MethodData* trap_mdo, int trap_bci, int reason);
477 };
478 
479 
480 class DeoptimizationMarker : StackObj {  // for profiling
481   static bool _is_active;
482 public:
483   DeoptimizationMarker()  { _is_active = true; }
484   ~DeoptimizationMarker() { _is_active = false; }
485   static bool is_active() { return _is_active; }
486 };
487 
488 #endif // SHARE_RUNTIME_DEOPTIMIZATION_HPP