1 /*
2 * Copyright (c) 1997, 2012, 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 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_speculate_class_check, // saw unexpected object class from type speculation
63 Reason_rtm_state_change, // rtm state change detected
64 Reason_LIMIT,
65 // Note: Keep this enum in sync. with _trap_reason_name.
66 Reason_RECORDED_LIMIT = Reason_bimorphic // some are not recorded per bc
67 // Note: Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of
68 // DataLayout::trap_bits. This dependency is enforced indirectly
69 // via asserts, to avoid excessive direct header-to-header dependencies.
70 // See Deoptimization::trap_state_reason and class DataLayout.
71 };
72
73 // What action must be taken by the runtime?
74 enum DeoptAction {
75 Action_none, // just interpret, do not invalidate nmethod
76 Action_maybe_recompile, // recompile the nmethod; need not invalidate
77 Action_reinterpret, // invalidate the nmethod, reset IC, maybe recompile
78 Action_make_not_entrant, // invalidate the nmethod, recompile (probably)
79 Action_make_not_compilable, // invalidate the nmethod and do not compile
80 Action_LIMIT
81 // Note: Keep this enum in sync. with _trap_action_name.
82 };
83
84 enum {
85 _action_bits = 3,
86 _reason_bits = 5,
87 _action_shift = 0,
88 _reason_shift = _action_shift+_action_bits,
89 BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
90 };
91
92 enum UnpackType {
93 Unpack_deopt = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
94 Unpack_exception = 1, // exception is pending
95 Unpack_uncommon_trap = 2, // redo last byte code (C2 only)
96 Unpack_reexecute = 3 // reexecute bytecode (C1 only)
97 };
98
99 // Checks all compiled methods. Invalid methods are deleted and
100 // corresponding activations are deoptimized.
101 static int deoptimize_dependents();
102
103 // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame
104 static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);
105
106 private:
107 // Does the actual work for deoptimizing a single frame
108 static void deoptimize_single_frame(JavaThread* thread, frame fr);
109
110 // Helper function to revoke biases of all monitors in frame if UseBiasedLocking
111 // is enabled
112 static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);
113 // Helper function to revoke biases of all monitors in frames
114 // executing in a particular CodeBlob if UseBiasedLocking is enabled
115 static void revoke_biases_of_monitors(CodeBlob* cb);
116
117 #ifdef COMPILER2
118 // Support for restoring non-escaping objects
119 static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);
120 static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
121 static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
122 static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);
123 static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread);
124 NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)
125 #endif // COMPILER2
126
127 public:
128 static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);
129
130 // Interface used for unpacking deoptimized frames
131
132 // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
133 // This is only a CheapObj to ease debugging after a deopt failure
134 class UnrollBlock : public CHeapObj<mtCompiler> {
135 private:
136 int _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
137 int _caller_adjustment; // Adjustment, in bytes, to caller's SP by initial interpreted frame
138 int _number_of_frames; // Number frames to unroll
139 int _total_frame_sizes; // Total of number*sizes frames
140 intptr_t* _frame_sizes; // Array of frame sizes, in bytes, for unrolling the stack
141 address* _frame_pcs; // Array of frame pc's, in bytes, for unrolling the stack
142 intptr_t* _register_block; // Block for storing callee-saved registers.
143 BasicType _return_type; // Tells if we have to restore double or long return value
144 intptr_t _initial_info; // Platform dependent data for the sender frame (was FP on x86)
145 int _caller_actual_parameters; // The number of actual arguments at the
146 // interpreted caller of the deoptimized frame
147
148 // The following fields are used as temps during the unpacking phase
149 // (which is tight on registers, especially on x86). They really ought
150 // to be PD variables but that involves moving this class into its own
151 // file to use the pd include mechanism. Maybe in a later cleanup ...
152 intptr_t _counter_temp; // SHOULD BE PD VARIABLE (x86 frame count temp)
153 intptr_t _unpack_kind; // SHOULD BE PD VARIABLE (x86 unpack kind)
154 intptr_t _sender_sp_temp; // SHOULD BE PD VARIABLE (x86 sender_sp)
155 public:
156 // Constructor
157 UnrollBlock(int size_of_deoptimized_frame,
158 int caller_adjustment,
159 int caller_actual_parameters,
160 int number_of_frames,
161 intptr_t* frame_sizes,
162 address* frames_pcs,
163 BasicType return_type);
164 ~UnrollBlock();
165
166 // Returns where a register is located.
167 intptr_t* value_addr_at(int register_number) const;
168
169 // Accessors
170 intptr_t* frame_sizes() const { return _frame_sizes; }
171 int number_of_frames() const { return _number_of_frames; }
172 address* frame_pcs() const { return _frame_pcs ; }
173
174 // Returns the total size of frames
175 int size_of_frames() const;
176
177 void set_initial_info(intptr_t info) { _initial_info = info; }
178
179 int caller_actual_parameters() const { return _caller_actual_parameters; }
180
181 // Accessors used by the code generator for the unpack stub.
182 static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
183 static int caller_adjustment_offset_in_bytes() { return offset_of(UnrollBlock, _caller_adjustment); }
184 static int number_of_frames_offset_in_bytes() { return offset_of(UnrollBlock, _number_of_frames); }
185 static int frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _frame_sizes); }
186 static int total_frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _total_frame_sizes); }
187 static int frame_pcs_offset_in_bytes() { return offset_of(UnrollBlock, _frame_pcs); }
188 static int register_block_offset_in_bytes() { return offset_of(UnrollBlock, _register_block); }
189 static int return_type_offset_in_bytes() { return offset_of(UnrollBlock, _return_type); }
190 static int counter_temp_offset_in_bytes() { return offset_of(UnrollBlock, _counter_temp); }
191 static int initial_info_offset_in_bytes() { return offset_of(UnrollBlock, _initial_info); }
192 static int unpack_kind_offset_in_bytes() { return offset_of(UnrollBlock, _unpack_kind); }
193 static int sender_sp_temp_offset_in_bytes() { return offset_of(UnrollBlock, _sender_sp_temp); }
194
195 BasicType return_type() const { return _return_type; }
196 void print();
197 };
198
199 //** Returns an UnrollBlock continuing information
200 // how to make room for the resulting interpreter frames.
201 // Called by assembly stub after execution has returned to
202 // deoptimized frame.
203 // @argument thread. Thread where stub_frame resides.
204 // @see OptoRuntime::deoptimization_fetch_unroll_info_C
205 static UnrollBlock* fetch_unroll_info(JavaThread* thread);
206
207 //** Unpacks vframeArray onto execution stack
208 // Called by assembly stub after execution has returned to
209 // deoptimized frame and after the stack unrolling.
210 // @argument thread. Thread where stub_frame resides.
211 // @argument exec_mode. Determines how execution should be continued in top frame.
212 // 0 means continue after current byte code
213 // 1 means exception has happened, handle exception
214 // 2 means reexecute current bytecode (for uncommon traps).
215 // @see OptoRuntime::deoptimization_unpack_frames_C
216 // Return BasicType of call return type, if any
217 static BasicType unpack_frames(JavaThread* thread, int exec_mode);
218
219 // Cleans up deoptimization bits on thread after unpacking or in the
220 // case of an exception.
221 static void cleanup_deopt_info(JavaThread *thread,
222 vframeArray * array);
223
224 // Restores callee saved values from deoptimized frame into oldest interpreter frame
225 // so caller of the deoptimized frame will get back the values it expects.
226 static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
227
228 //** Performs an uncommon trap for compiled code.
229 // The top most compiler frame is converted into interpreter frames
230 static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
231 // Helper routine that enters the VM and may block
232 static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);
233
234 //** Deoptimizes the frame identified by id.
235 // Only called from VMDeoptimizeFrame
236 // @argument thread. Thread where stub_frame resides.
237 // @argument id. id of frame that should be deoptimized.
238 static void deoptimize_frame_internal(JavaThread* thread, intptr_t* id);
239
240 // If thread is not the current thread then execute
241 // VM_DeoptimizeFrame otherwise deoptimize directly.
242 static void deoptimize_frame(JavaThread* thread, intptr_t* id);
243
244 // Statistics
245 static void gather_statistics(DeoptReason reason, DeoptAction action,
246 Bytecodes::Code bc = Bytecodes::_illegal);
247 static void print_statistics();
248
249 // How much room to adjust the last frame's SP by, to make space for
250 // the callee's interpreter frame (which expects locals to be next to
251 // incoming arguments)
252 static int last_frame_adjust(int callee_parameters, int callee_locals);
253
254 // trap_request codes
255 static DeoptReason trap_request_reason(int trap_request) {
256 if (trap_request < 0)
257 return (DeoptReason)
258 ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
259 else
260 // standard reason for unloaded CP entry
261 return Reason_unloaded;
262 }
263 static DeoptAction trap_request_action(int trap_request) {
264 if (trap_request < 0)
265 return (DeoptAction)
266 ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
267 else
268 // standard action for unloaded CP entry
269 return _unloaded_action;
270 }
271 static int trap_request_index(int trap_request) {
272 if (trap_request < 0)
273 return -1;
274 else
275 return trap_request;
276 }
277 static int make_trap_request(DeoptReason reason, DeoptAction action,
278 int index = -1) {
279 assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
280 assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
281 int trap_request;
282 if (index != -1)
283 trap_request = index;
284 else
285 trap_request = (~(((reason) << _reason_shift)
286 + ((action) << _action_shift)));
287 assert(reason == trap_request_reason(trap_request), "valid reason");
288 assert(action == trap_request_action(trap_request), "valid action");
289 assert(index == trap_request_index(trap_request), "valid index");
290 return trap_request;
291 }
292
293 // The trap_state stored in a MDO is decoded here.
294 // It records two items of information.
295 // reason: If a deoptimization happened here, what its reason was,
296 // or if there were multiple deopts with differing reasons.
297 // recompiled: If a deoptimization here triggered a recompilation.
298 // Note that not all reasons are recorded per-bci.
299 static DeoptReason trap_state_reason(int trap_state);
300 static int trap_state_has_reason(int trap_state, int reason);
301 static int trap_state_add_reason(int trap_state, int reason);
302 static bool trap_state_is_recompiled(int trap_state);
303 static int trap_state_set_recompiled(int trap_state, bool z);
304 static const char* format_trap_state(char* buf, size_t buflen,
305 int trap_state);
306
307 static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
308 return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
309 }
310
311 static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
312 if (reason_is_recorded_per_bytecode(reason))
313 return reason;
314 else if (reason == Reason_div0_check) // null check due to divide-by-zero?
315 return Reason_null_check; // recorded per BCI as a null check
316 else if (reason == Reason_speculate_class_check)
317 return Reason_class_check;
318 else
319 return Reason_none;
320 }
321
322 static bool reason_is_speculate(int reason) {
323 if (reason == Reason_speculate_class_check) {
324 return true;
325 }
326 return false;
327 }
328
329 static uint per_method_trap_limit(int reason) {
330 return reason_is_speculate(reason) ? (uint)PerMethodSpecTrapLimit : (uint)PerMethodTrapLimit;
331 }
332
333 static const char* trap_reason_name(int reason);
334 static const char* trap_action_name(int action);
335 // Format like reason='foo' action='bar' index='123'.
336 // This is suitable both for XML and for tty output.
337 static const char* format_trap_request(char* buf, size_t buflen,
338 int trap_request);
339
340 static jint total_deoptimization_count();
341 static jint deoptimization_count(DeoptReason reason);
342
343 // JVMTI PopFrame support
344
345 // Preserves incoming arguments to the popped frame when it is
346 // returning to a deoptimized caller
347 static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
348
349 private:
350 static MethodData* get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);
351 // Update the mdo's count and per-BCI reason bits, returning previous state:
352 static ProfileData* query_update_method_data(MethodData* trap_mdo,
353 int trap_bci,
354 DeoptReason reason,
355 Method* compiled_method,
356 //outputs:
357 uint& ret_this_trap_count,
358 bool& ret_maybe_prior_trap,
359 bool& ret_maybe_prior_recompile);
360 // class loading support for uncommon trap
361 static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);
362 static void load_class_by_index(constantPoolHandle constant_pool, int index);
363
364 static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);
365
366 static DeoptAction _unloaded_action; // == Action_reinterpret;
367 static const char* _trap_reason_name[Reason_LIMIT];
368 static const char* _trap_action_name[Action_LIMIT];
369
370 static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
371 // Note: Histogram array size is 1-2 Kb.
372
373 public:
374 static void update_method_data_from_interpreter(MethodData* trap_mdo, int trap_bci, int reason);
375 };
376
377 class DeoptimizationMarker : StackObj { // for profiling
378 static bool _is_active;
379 public:
380 DeoptimizationMarker() { _is_active = true; }
381 ~DeoptimizationMarker() { _is_active = false; }
382 static bool is_active() { return _is_active; }
383 };
384
385 #endif // SHARE_VM_RUNTIME_DEOPTIMIZATION_HPP