1 /*
2 * Copyright 1997-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any 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 Reason_null_check, // saw unexpected null or zero divisor (@bci)
37 Reason_null_assert, // saw unexpected non-null or non-zero (@bci)
38 Reason_range_check, // saw unexpected array index (@bci)
39 Reason_class_check, // saw unexpected object class (@bci)
40 Reason_array_check, // saw unexpected array class (aastore @bci)
41 Reason_intrinsic, // saw unexpected operand to intrinsic (@bci)
42 Reason_unloaded, // unloaded class or constant pool entry
43 Reason_uninitialized, // bad class state (uninitialized)
44 Reason_unreached, // code is not reached, compiler
45 Reason_unhandled, // arbitrary compiler limitation
46 Reason_constraint, // arbitrary runtime constraint violated
47 Reason_div0_check, // a null_check due to division by zero
48 Reason_age, // nmethod too old; tier threshold reached
49 Reason_predicate, // compiler generated predicate failed
50 Reason_LIMIT,
51 // Note: Keep this enum in sync. with _trap_reason_name.
52 Reason_RECORDED_LIMIT = Reason_unloaded // some are not recorded per bc
53 // Note: Reason_RECORDED_LIMIT should be < 8 to fit into 3 bits of
54 // DataLayout::trap_bits. This dependency is enforced indirectly
55 // via asserts, to avoid excessive direct header-to-header dependencies.
56 // See Deoptimization::trap_state_reason and class DataLayout.
57 };
58
59 // What action must be taken by the runtime?
60 enum DeoptAction {
61 Action_none, // just interpret, do not invalidate nmethod
62 Action_maybe_recompile, // recompile the nmethod; need not invalidate
63 Action_reinterpret, // invalidate the nmethod, reset IC, maybe recompile
64 Action_make_not_entrant, // invalidate the nmethod, recompile (probably)
65 Action_make_not_compilable, // invalidate the nmethod and do not compile
66 Action_LIMIT
67 // Note: Keep this enum in sync. with _trap_action_name.
68 };
69
70 enum {
71 _action_bits = 3,
72 _reason_bits = 4,
73 _action_shift = 0,
74 _reason_shift = _action_shift+_action_bits,
75 BC_CASE_LIMIT = PRODUCT_ONLY(1) NOT_PRODUCT(4) // for _deoptimization_hist
76 };
77
78 enum UnpackType {
79 Unpack_deopt = 0, // normal deoptimization, use pc computed in unpack_vframe_on_stack
80 Unpack_exception = 1, // exception is pending
81 Unpack_uncommon_trap = 2, // redo last byte code (C2 only)
82 Unpack_reexecute = 3 // reexecute bytecode (C1 only)
83 };
84
85 // Checks all compiled methods. Invalid methods are deleted and
86 // corresponding activations are deoptimized.
87 static int deoptimize_dependents();
88
89 // Deoptimizes a frame lazily. nmethod gets patched deopt happens on return to the frame
90 static void deoptimize(JavaThread* thread, frame fr, RegisterMap *reg_map);
91
92 private:
93 // Does the actual work for deoptimizing a single frame
94 static void deoptimize_single_frame(JavaThread* thread, frame fr);
95
96 // Helper function to revoke biases of all monitors in frame if UseBiasedLocking
97 // is enabled
98 static void revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map);
99 // Helper function to revoke biases of all monitors in frames
100 // executing in a particular CodeBlob if UseBiasedLocking is enabled
101 static void revoke_biases_of_monitors(CodeBlob* cb);
102
103 #ifdef COMPILER2
104 // Support for restoring non-escaping objects
105 static bool realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS);
106 static void reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type);
107 static void reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj);
108 static void reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects);
109 static void relock_objects(GrowableArray<MonitorInfo*>* monitors, JavaThread* thread);
110 NOT_PRODUCT(static void print_objects(GrowableArray<ScopeValue*>* objects);)
111 #endif // COMPILER2
112
113 public:
114 static vframeArray* create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk);
115
116 // Interface used for unpacking deoptimized frames
117
118 // UnrollBlock is returned by fetch_unroll_info() to the deoptimization handler (blob).
119 // This is only a CheapObj to ease debugging after a deopt failure
120 class UnrollBlock : public CHeapObj {
121 private:
122 int _size_of_deoptimized_frame; // Size, in bytes, of current deoptimized frame
123 int _caller_adjustment; // Adjustment, in bytes, to caller's SP by initial interpreted frame
124 int _number_of_frames; // Number frames to unroll
125 int _total_frame_sizes; // Total of number*sizes frames
126 intptr_t* _frame_sizes; // Array of frame sizes, in bytes, for unrolling the stack
127 address* _frame_pcs; // Array of frame pc's, in bytes, for unrolling the stack
128 intptr_t* _register_block; // Block for storing callee-saved registers.
129 BasicType _return_type; // Tells if we have to restore double or long return value
130 // The following fields are used as temps during the unpacking phase
131 // (which is tight on registers, especially on x86). They really ought
132 // to be PD variables but that involves moving this class into its own
133 // file to use the pd include mechanism. Maybe in a later cleanup ...
134 intptr_t _counter_temp; // SHOULD BE PD VARIABLE (x86 frame count temp)
135 intptr_t _initial_fp; // SHOULD BE PD VARIABLE (x86/c2 initial ebp)
136 intptr_t _unpack_kind; // SHOULD BE PD VARIABLE (x86 unpack kind)
137 intptr_t _sender_sp_temp; // SHOULD BE PD VARIABLE (x86 sender_sp)
138 public:
139 // Constructor
140 UnrollBlock(int size_of_deoptimized_frame,
141 int caller_adjustment,
142 int number_of_frames,
143 intptr_t* frame_sizes,
144 address* frames_pcs,
145 BasicType return_type);
146 ~UnrollBlock();
147
148 // Returns where a register is located.
149 intptr_t* value_addr_at(int register_number) const;
150
151 // Accessors
152 intptr_t* frame_sizes() const { return _frame_sizes; }
153 int number_of_frames() const { return _number_of_frames; }
154 address* frame_pcs() const { return _frame_pcs ; }
155
156 // Returns the total size of frames
157 int size_of_frames() const;
158
159 // Accessors used by the code generator for the unpack stub.
160 static int size_of_deoptimized_frame_offset_in_bytes() { return offset_of(UnrollBlock, _size_of_deoptimized_frame); }
161 static int caller_adjustment_offset_in_bytes() { return offset_of(UnrollBlock, _caller_adjustment); }
162 static int number_of_frames_offset_in_bytes() { return offset_of(UnrollBlock, _number_of_frames); }
163 static int frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _frame_sizes); }
164 static int total_frame_sizes_offset_in_bytes() { return offset_of(UnrollBlock, _total_frame_sizes); }
165 static int frame_pcs_offset_in_bytes() { return offset_of(UnrollBlock, _frame_pcs); }
166 static int register_block_offset_in_bytes() { return offset_of(UnrollBlock, _register_block); }
167 static int return_type_offset_in_bytes() { return offset_of(UnrollBlock, _return_type); }
168 static int counter_temp_offset_in_bytes() { return offset_of(UnrollBlock, _counter_temp); }
169 static int initial_fp_offset_in_bytes() { return offset_of(UnrollBlock, _initial_fp); }
170 static int unpack_kind_offset_in_bytes() { return offset_of(UnrollBlock, _unpack_kind); }
171 static int sender_sp_temp_offset_in_bytes() { return offset_of(UnrollBlock, _sender_sp_temp); }
172
173 BasicType return_type() const { return _return_type; }
174 void print();
175 };
176
177 //** Returns an UnrollBlock continuing information
178 // how to make room for the resulting interpreter frames.
179 // Called by assembly stub after execution has returned to
180 // deoptimized frame.
181 // @argument thread. Thread where stub_frame resides.
182 // @see OptoRuntime::deoptimization_fetch_unroll_info_C
183 static UnrollBlock* fetch_unroll_info(JavaThread* thread);
184
185 //** Unpacks vframeArray onto execution stack
186 // Called by assembly stub after execution has returned to
187 // deoptimized frame and after the stack unrolling.
188 // @argument thread. Thread where stub_frame resides.
189 // @argument exec_mode. Determines how execution should be continuted in top frame.
190 // 0 means continue after current byte code
191 // 1 means exception has happened, handle exception
192 // 2 means reexecute current bytecode (for uncommon traps).
193 // @see OptoRuntime::deoptimization_unpack_frames_C
194 // Return BasicType of call return type, if any
195 static BasicType unpack_frames(JavaThread* thread, int exec_mode);
196
197 // Cleans up deoptimization bits on thread after unpacking or in the
198 // case of an exception.
199 static void cleanup_deopt_info(JavaThread *thread,
200 vframeArray * array);
201
202 // Restores callee saved values from deoptimized frame into oldest interpreter frame
203 // so caller of the deoptimized frame will get back the values it expects.
204 static void unwind_callee_save_values(frame* f, vframeArray* vframe_array);
205
206 //** Performs an uncommon trap for compiled code.
207 // The top most compiler frame is converted into interpreter frames
208 static UnrollBlock* uncommon_trap(JavaThread* thread, jint unloaded_class_index);
209 // Helper routine that enters the VM and may block
210 static void uncommon_trap_inner(JavaThread* thread, jint unloaded_class_index);
211
212 //** Deoptimizes the frame identified by id.
213 // Only called from VMDeoptimizeFrame
214 // @argument thread. Thread where stub_frame resides.
215 // @argument id. id of frame that should be deoptimized.
216 static void deoptimize_frame(JavaThread* thread, intptr_t* id);
217
218 // Statistics
219 static void gather_statistics(DeoptReason reason, DeoptAction action,
220 Bytecodes::Code bc = Bytecodes::_illegal);
221 static void print_statistics();
222
223 // How much room to adjust the last frame's SP by, to make space for
224 // the callee's interpreter frame (which expects locals to be next to
225 // incoming arguments)
226 static int last_frame_adjust(int callee_parameters, int callee_locals);
227
228 // trap_request codes
229 static DeoptReason trap_request_reason(int trap_request) {
230 if (trap_request < 0)
231 return (DeoptReason)
232 ((~(trap_request) >> _reason_shift) & right_n_bits(_reason_bits));
233 else
234 // standard reason for unloaded CP entry
235 return Reason_unloaded;
236 }
237 static DeoptAction trap_request_action(int trap_request) {
238 if (trap_request < 0)
239 return (DeoptAction)
240 ((~(trap_request) >> _action_shift) & right_n_bits(_action_bits));
241 else
242 // standard action for unloaded CP entry
243 return _unloaded_action;
244 }
245 static int trap_request_index(int trap_request) {
246 if (trap_request < 0)
247 return -1;
248 else
249 return trap_request;
250 }
251 static int make_trap_request(DeoptReason reason, DeoptAction action,
252 int index = -1) {
253 assert((1 << _reason_bits) >= Reason_LIMIT, "enough bits");
254 assert((1 << _action_bits) >= Action_LIMIT, "enough bits");
255 int trap_request;
256 if (index != -1)
257 trap_request = index;
258 else
259 trap_request = (~(((reason) << _reason_shift)
260 + ((action) << _action_shift)));
261 assert(reason == trap_request_reason(trap_request), "valid reason");
262 assert(action == trap_request_action(trap_request), "valid action");
263 assert(index == trap_request_index(trap_request), "valid index");
264 return trap_request;
265 }
266
267 // The trap_state stored in a MDO is decoded here.
268 // It records two items of information.
269 // reason: If a deoptimization happened here, what its reason was,
270 // or if there were multiple deopts with differing reasons.
271 // recompiled: If a deoptimization here triggered a recompilation.
272 // Note that not all reasons are recorded per-bci.
273 static DeoptReason trap_state_reason(int trap_state);
274 static int trap_state_has_reason(int trap_state, int reason);
275 static int trap_state_add_reason(int trap_state, int reason);
276 static bool trap_state_is_recompiled(int trap_state);
277 static int trap_state_set_recompiled(int trap_state, bool z);
278 static const char* format_trap_state(char* buf, size_t buflen,
279 int trap_state);
280
281 static bool reason_is_recorded_per_bytecode(DeoptReason reason) {
282 return reason > Reason_none && reason < Reason_RECORDED_LIMIT;
283 }
284
285 static DeoptReason reason_recorded_per_bytecode_if_any(DeoptReason reason) {
286 if (reason_is_recorded_per_bytecode(reason))
287 return reason;
288 else if (reason == Reason_div0_check) // null check due to divide-by-zero?
289 return Reason_null_check; // recorded per BCI as a null check
290 else
291 return Reason_none;
292 }
293
294 static const char* trap_reason_name(int reason);
295 static const char* trap_action_name(int action);
296 // Format like reason='foo' action='bar' index='123'.
297 // This is suitable both for XML and for tty output.
298 static const char* format_trap_request(char* buf, size_t buflen,
299 int trap_request);
300
301 static jint total_deoptimization_count();
302 static jint deoptimization_count(DeoptReason reason);
303
304 // JVMTI PopFrame support
305
306 // Preserves incoming arguments to the popped frame when it is
307 // returning to a deoptimized caller
308 static void popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address);
309
310 private:
311 enum {
312 _no_count = -1
313 };
314
315 static void reset_invocation_counter(ScopeDesc* trap_scope, jint count = _no_count);
316
317 static methodDataOop get_method_data(JavaThread* thread, methodHandle m, bool create_if_missing);
318 // Update the mdo's count and per-BCI reason bits, returning previous state:
319 static ProfileData* query_update_method_data(methodDataHandle trap_mdo,
320 int trap_bci,
321 DeoptReason reason,
322 //outputs:
323 uint& ret_this_trap_count,
324 bool& ret_maybe_prior_trap,
325 bool& ret_maybe_prior_recompile);
326 // class loading support for uncommon trap
327 static void load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS);
328 static void load_class_by_index(constantPoolHandle constant_pool, int index);
329
330 static UnrollBlock* fetch_unroll_info_helper(JavaThread* thread);
331
332 static DeoptAction _unloaded_action; // == Action_reinterpret;
333 static const char* _trap_reason_name[Reason_LIMIT];
334 static const char* _trap_action_name[Action_LIMIT];
335
336 static juint _deoptimization_hist[Reason_LIMIT][1+Action_LIMIT][BC_CASE_LIMIT];
337 // Note: Histogram array size is 1-2 Kb.
338
339 public:
340 static void update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason);
341 };
342
343 class DeoptimizationMarker : StackObj { // for profiling
344 static bool _is_active;
345 public:
346 DeoptimizationMarker() { _is_active = true; }
347 ~DeoptimizationMarker() { _is_active = false; }
348 static bool is_active() { return _is_active; }
349 };