1 /*
2 * Copyright (c) 1997, 2008, 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 class ProfileData;
26 class vframeArray;
27 class MonitorValue;
28 class ObjectValue;
29
30 class Deoptimization : AllStatic {
31 public:
32 // What condition caused the deoptimization?
33 enum DeoptReason {
34 Reason_many = -1, // indicates presence of several reasons
35 Reason_none = 0, // indicates absence of a relevant deopt.
36 // Next 7 reasons are recorded per bytecode in DataLayout::trap_bits
37 Reason_null_check, // saw unexpected null or zero divisor (@bci)
38 Reason_null_assert, // saw unexpected non-null or non-zero (@bci)
39 Reason_range_check, // saw unexpected array index (@bci)
40 Reason_class_check, // saw unexpected object class (@bci)
41 Reason_array_check, // saw unexpected array class (aastore @bci)
42 Reason_intrinsic, // saw unexpected operand to intrinsic (@bci)
43 Reason_bimorphic, // saw unexpected object class in bimorphic inlining (@bci)
44
45 Reason_unloaded, // unloaded class or constant pool entry
46 Reason_uninitialized, // bad class state (uninitialized)
47 Reason_unreached, // code is not reached, compiler
48 Reason_unhandled, // arbitrary compiler limitation
49 Reason_constraint, // arbitrary runtime constraint violated
50 Reason_div0_check, // a null_check due to division by zero
51 Reason_age, // nmethod too old; tier threshold reached
52 Reason_predicate, // compiler generated predicate failed
53 Reason_LIMIT,
54 // Note: Keep this enum in sync. with _trap_reason_name.
55 Reason_RECORDED_LIMIT = Reason_bimorphic // some are not recorded per bc
56 // Note: Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of
57 // DataLayout::trap_bits. This dependency is enforced indirectly
58 // via asserts, to avoid excessive direct header-to-header dependencies.
59 // See Deoptimization::trap_state_reason and class DataLayout.
60 };
61
62 // What action must be taken by the runtime?
63 enum DeoptAction {
64 Action_none, // just interpret, do not invalidate nmethod
65 Action_maybe_recompile, // recompile the nmethod; need not invalidate
66 Action_reinterpret, // invalidate the nmethod, reset IC, maybe recompile
67 Action_make_not_entrant, // invalidate the nmethod, recompile (probably)
68 Action_make_not_compilable, // invalidate the nmethod and do not compile
69 Action_LIMIT
70 // Note: Keep this enum in sync. with _trap_action_name.
71 };
72
73 enum {
74 _action_bits = 3,
75 _reason_bits = 4,
76 _action_shift = 0,
77 _reason_shift = _action_shift+_action_bits,
78 BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
79 };
80
81 enum UnpackType {
82 Unpack_deopt = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
83 Unpack_exception = 1, // exception is pending
84 Unpack_uncommon_trap = 2, // redo last byte code (C2 only)
85 Unpack_reexecute = 3 // reexecute bytecode (C1 only)
86 };
87
88 // Checks all compiled methods. Invalid methods are deleted and
89 // corresponding activations are deoptimized.
90 static int deoptimize_dependents();
91
92 // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame
93 static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);
94
95 private:
96 // Does the actual work for deoptimizing a single frame
97 static void deoptimize_single_frame(JavaThread* thread, frame fr);
98
99 // Helper function to revoke biases of all monitors in frame if UseBiasedLocking
100 // is enabled
101 static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);
102 // Helper function to revoke biases of all monitors in frames
103 // executing in a particular CodeBlob if UseBiasedLocking is enabled
104 static void revoke_biases_of_monitors(CodeBlob* cb);
105
106 #ifdef COMPILER2
107 // Support for restoring non-escaping objects
108 static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);
109 static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
110 static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
111 static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);
112 static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread);
113 NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)
114 #endif // COMPILER2
115
116 public:
117 static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);
118
119 // Interface used for unpacking deoptimized frames
120
121 // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
122 // This is only a CheapObj to ease debugging after a deopt failure
123 class UnrollBlock : public CHeapObj {
124 private:
125 int _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
126 int _caller_adjustment; // Adjustment, in bytes, to caller's SP by initial interpreted frame
127 int _number_of_frames; // Number frames to unroll
128 int _total_frame_sizes; // Total of number*sizes frames
129 intptr_t* _frame_sizes; // Array of frame sizes, in bytes, for unrolling the stack
130 address* _frame_pcs; // Array of frame pc's, in bytes, for unrolling the stack
131 intptr_t* _register_block; // Block for storing callee-saved registers.
132 BasicType _return_type; // Tells if we have to restore double or long return value
133 // The following fields are used as temps during the unpacking phase
134 // (which is tight on registers, especially on x86). They really ought
135 // to be PD variables but that involves moving this class into its own
136 // file to use the pd include mechanism. Maybe in a later cleanup ...
137 intptr_t _counter_temp; // SHOULD BE PD VARIABLE (x86 frame count temp)
138 intptr_t _initial_fp; // SHOULD BE PD VARIABLE (x86/c2 initial ebp)
139 intptr_t _unpack_kind; // SHOULD BE PD VARIABLE (x86 unpack kind)
140 intptr_t _sender_sp_temp; // SHOULD BE PD VARIABLE (x86 sender_sp)
141 public:
142 // Constructor
143 UnrollBlock(int size_of_deoptimized_frame,
144 int caller_adjustment,
145 int number_of_frames,
146 intptr_t* frame_sizes,
147 address* frames_pcs,
148 BasicType return_type);
149 ~UnrollBlock();
150
151 // Returns where a register is located.
152 intptr_t* value_addr_at(int register_number) const;
153
154 // Accessors
155 intptr_t* frame_sizes() const { return _frame_sizes; }
156 int number_of_frames() const { return _number_of_frames; }
157 address* frame_pcs() const { return _frame_pcs ; }
158
159 // Returns the total size of frames
160 int size_of_frames() const;
161
162 // Accessors used by the code generator for the unpack stub.
163 static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
164 static int caller_adjustment_offset_in_bytes() { return offset_of(UnrollBlock, _caller_adjustment); }
165 static int number_of_frames_offset_in_bytes() { return offset_of(UnrollBlock, _number_of_frames); }
166 static int frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _frame_sizes); }
167 static int total_frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _total_frame_sizes); }
168 static int frame_pcs_offset_in_bytes() { return offset_of(UnrollBlock, _frame_pcs); }
169 static int register_block_offset_in_bytes() { return offset_of(UnrollBlock, _register_block); }
170 static int return_type_offset_in_bytes() { return offset_of(UnrollBlock, _return_type); }
171 static int counter_temp_offset_in_bytes() { return offset_of(UnrollBlock, _counter_temp); }
172 static int initial_fp_offset_in_bytes() { return offset_of(UnrollBlock, _initial_fp); }
173 static int unpack_kind_offset_in_bytes() { return offset_of(UnrollBlock, _unpack_kind); }
174 static int sender_sp_temp_offset_in_bytes() { return offset_of(UnrollBlock, _sender_sp_temp); }
175
176 BasicType return_type() const { return _return_type; }
177 void print();
178 };
179
180 //** Returns an UnrollBlock continuing information
181 // how to make room for the resulting interpreter frames.
182 // Called by assembly stub after execution has returned to
183 // deoptimized frame.
184 // @argument thread. Thread where stub_frame resides.
185 // @see OptoRuntime::deoptimization_fetch_unroll_info_C
186 static UnrollBlock* fetch_unroll_info(JavaThread* thread);
187
188 //** Unpacks vframeArray onto execution stack
189 // Called by assembly stub after execution has returned to
190 // deoptimized frame and after the stack unrolling.
191 // @argument thread. Thread where stub_frame resides.
192 // @argument exec_mode. Determines how execution should be continuted in top frame.
193 // 0 means continue after current byte code
194 // 1 means exception has happened, handle exception
195 // 2 means reexecute current bytecode (for uncommon traps).
196 // @see OptoRuntime::deoptimization_unpack_frames_C
197 // Return BasicType of call return type, if any
198 static BasicType unpack_frames(JavaThread* thread, int exec_mode);
199
200 // Cleans up deoptimization bits on thread after unpacking or in the
201 // case of an exception.
202 static void cleanup_deopt_info(JavaThread *thread,
203 vframeArray * array);
204
205 // Restores callee saved values from deoptimized frame into oldest interpreter frame
206 // so caller of the deoptimized frame will get back the values it expects.
207 static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
208
209 //** Performs an uncommon trap for compiled code.
210 // The top most compiler frame is converted into interpreter frames
211 static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
212 // Helper routine that enters the VM and may block
213 static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);
214
215 //** Deoptimizes the frame identified by id.
216 // Only called from VMDeoptimizeFrame
217 // @argument thread. Thread where stub_frame resides.
218 // @argument id. id of frame that should be deoptimized.
219 static void deoptimize_frame(JavaThread* thread, intptr_t* id);
220
221 // Statistics
222 static void gather_statistics(DeoptReason reason, DeoptAction action,
223 Bytecodes::Code bc = Bytecodes::_illegal);
224 static void print_statistics();
225
226 // How much room to adjust the last frame's SP by, to make space for
227 // the callee's interpreter frame (which expects locals to be next to
228 // incoming arguments)
229 static int last_frame_adjust(int callee_parameters, int callee_locals);
230
231 // trap_request codes
232 static DeoptReason trap_request_reason(int trap_request) {
233 if (trap_request < 0)
234 return (DeoptReason)
235 ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
236 else
237 // standard reason for unloaded CP entry
238 return Reason_unloaded;
239 }
240 static DeoptAction trap_request_action(int trap_request) {
241 if (trap_request < 0)
242 return (DeoptAction)
243 ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
244 else
245 // standard action for unloaded CP entry
246 return _unloaded_action;
247 }
248 static int trap_request_index(int trap_request) {
249 if (trap_request < 0)
250 return -1;
251 else
252 return trap_request;
253 }
254 static int make_trap_request(DeoptReason reason, DeoptAction action,
255 int index = -1) {
256 assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
257 assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
258 int trap_request;
259 if (index != -1)
260 trap_request = index;
261 else
262 trap_request = (~(((reason) << _reason_shift)
263 + ((action) << _action_shift)));
264 assert(reason == trap_request_reason(trap_request), "valid reason");
265 assert(action == trap_request_action(trap_request), "valid action");
266 assert(index == trap_request_index(trap_request), "valid index");
267 return trap_request;
268 }
269
270 // The trap_state stored in a MDO is decoded here.
271 // It records two items of information.
272 // reason: If a deoptimization happened here, what its reason was,
273 // or if there were multiple deopts with differing reasons.
274 // recompiled: If a deoptimization here triggered a recompilation.
275 // Note that not all reasons are recorded per-bci.
276 static DeoptReason trap_state_reason(int trap_state);
277 static int trap_state_has_reason(int trap_state, int reason);
278 static int trap_state_add_reason(int trap_state, int reason);
279 static bool trap_state_is_recompiled(int trap_state);
280 static int trap_state_set_recompiled(int trap_state, bool z);
281 static const char* format_trap_state(char* buf, size_t buflen,
282 int trap_state);
283
284 static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
285 return reason > Reason_none && reason <= Reason_RECORDED_LIMIT;
286 }
287
288 static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
289 if (reason_is_recorded_per_bytecode(reason))
290 return reason;
291 else if (reason == Reason_div0_check) // null check due to divide-by-zero?
292 return Reason_null_check; // recorded per BCI as a null check
293 else
294 return Reason_none;
295 }
296
297 static const char* trap_reason_name(int reason);
298 static const char* trap_action_name(int action);
299 // Format like reason='foo' action='bar' index='123'.
300 // This is suitable both for XML and for tty output.
301 static const char* format_trap_request(char* buf, size_t buflen,
302 int trap_request);
303
304 static jint total_deoptimization_count();
305 static jint deoptimization_count(DeoptReason reason);
306
307 // JVMTI PopFrame support
308
309 // Preserves incoming arguments to the popped frame when it is
310 // returning to a deoptimized caller
311 static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
312
313 private:
314 static methodDataOop get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);
315 // Update the mdo's count and per-BCI reason bits, returning previous state:
316 static ProfileData* query_update_method_data(methodDataHandle trap_mdo,
317 int trap_bci,
318 DeoptReason reason,
319 //outputs:
320 uint& ret_this_trap_count,
321 bool& ret_maybe_prior_trap,
322 bool& ret_maybe_prior_recompile);
323 // class loading support for uncommon trap
324 static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);
325 static void load_class_by_index(constantPoolHandle constant_pool, int index);
326
327 static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);
328
329 static DeoptAction _unloaded_action; // == Action_reinterpret;
330 static const char* _trap_reason_name[Reason_LIMIT];
331 static const char* _trap_action_name[Action_LIMIT];
332
333 static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
334 // Note: Histogram array size is 1-2 Kb.
335
336 public:
337 static void update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason);
338 };
339
340 class DeoptimizationMarker : StackObj { // for profiling
341 static bool _is_active;
342 public:
343 DeoptimizationMarker() { _is_active = true; }
344 ~DeoptimizationMarker() { _is_active = false; }
345 static bool is_active() { return _is_active; }
346 };