Fri, 02 Sep 2011 20:58:21 -0700
7071307: MethodHandle bimorphic inlining should consider the frequency
Reviewed-by: twisti, roland, kvn, iveresov
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_OOPS_METHODDATAOOP_HPP
26 #define SHARE_VM_OOPS_METHODDATAOOP_HPP
28 #include "interpreter/bytecodes.hpp"
29 #include "memory/universe.hpp"
30 #include "oops/methodOop.hpp"
31 #include "oops/oop.hpp"
32 #include "runtime/orderAccess.hpp"
34 class BytecodeStream;
36 // The MethodData object collects counts and other profile information
37 // during zeroth-tier (interpretive) and first-tier execution.
38 // The profile is used later by compilation heuristics. Some heuristics
39 // enable use of aggressive (or "heroic") optimizations. An aggressive
40 // optimization often has a down-side, a corner case that it handles
41 // poorly, but which is thought to be rare. The profile provides
42 // evidence of this rarity for a given method or even BCI. It allows
43 // the compiler to back out of the optimization at places where it
44 // has historically been a poor choice. Other heuristics try to use
45 // specific information gathered about types observed at a given site.
46 //
47 // All data in the profile is approximate. It is expected to be accurate
48 // on the whole, but the system expects occasional inaccuraces, due to
49 // counter overflow, multiprocessor races during data collection, space
50 // limitations, missing MDO blocks, etc. Bad or missing data will degrade
51 // optimization quality but will not affect correctness. Also, each MDO
52 // is marked with its birth-date ("creation_mileage") which can be used
53 // to assess the quality ("maturity") of its data.
54 //
55 // Short (<32-bit) counters are designed to overflow to a known "saturated"
56 // state. Also, certain recorded per-BCI events are given one-bit counters
57 // which overflow to a saturated state which applied to all counters at
58 // that BCI. In other words, there is a small lattice which approximates
59 // the ideal of an infinite-precision counter for each event at each BCI,
60 // and the lattice quickly "bottoms out" in a state where all counters
61 // are taken to be indefinitely large.
62 //
63 // The reader will find many data races in profile gathering code, starting
64 // with invocation counter incrementation. None of these races harm correct
65 // execution of the compiled code.
67 // forward decl
68 class ProfileData;
70 // DataLayout
71 //
72 // Overlay for generic profiling data.
73 class DataLayout VALUE_OBJ_CLASS_SPEC {
74 private:
75 // Every data layout begins with a header. This header
76 // contains a tag, which is used to indicate the size/layout
77 // of the data, 4 bits of flags, which can be used in any way,
78 // 4 bits of trap history (none/one reason/many reasons),
79 // and a bci, which is used to tie this piece of data to a
80 // specific bci in the bytecodes.
81 union {
82 intptr_t _bits;
83 struct {
84 u1 _tag;
85 u1 _flags;
86 u2 _bci;
87 } _struct;
88 } _header;
90 // The data layout has an arbitrary number of cells, each sized
91 // to accomodate a pointer or an integer.
92 intptr_t _cells[1];
94 // Some types of data layouts need a length field.
95 static bool needs_array_len(u1 tag);
97 public:
98 enum {
99 counter_increment = 1
100 };
102 enum {
103 cell_size = sizeof(intptr_t)
104 };
106 // Tag values
107 enum {
108 no_tag,
109 bit_data_tag,
110 counter_data_tag,
111 jump_data_tag,
112 receiver_type_data_tag,
113 virtual_call_data_tag,
114 ret_data_tag,
115 branch_data_tag,
116 multi_branch_data_tag,
117 arg_info_data_tag
118 };
120 enum {
121 // The _struct._flags word is formatted as [trap_state:4 | flags:4].
122 // The trap state breaks down further as [recompile:1 | reason:3].
123 // This further breakdown is defined in deoptimization.cpp.
124 // See Deoptimization::trap_state_reason for an assert that
125 // trap_bits is big enough to hold reasons < Reason_RECORDED_LIMIT.
126 //
127 // The trap_state is collected only if ProfileTraps is true.
128 trap_bits = 1+3, // 3: enough to distinguish [0..Reason_RECORDED_LIMIT].
129 trap_shift = BitsPerByte - trap_bits,
130 trap_mask = right_n_bits(trap_bits),
131 trap_mask_in_place = (trap_mask << trap_shift),
132 flag_limit = trap_shift,
133 flag_mask = right_n_bits(flag_limit),
134 first_flag = 0
135 };
137 // Size computation
138 static int header_size_in_bytes() {
139 return cell_size;
140 }
141 static int header_size_in_cells() {
142 return 1;
143 }
145 static int compute_size_in_bytes(int cell_count) {
146 return header_size_in_bytes() + cell_count * cell_size;
147 }
149 // Initialization
150 void initialize(u1 tag, u2 bci, int cell_count);
152 // Accessors
153 u1 tag() {
154 return _header._struct._tag;
155 }
157 // Return a few bits of trap state. Range is [0..trap_mask].
158 // The state tells if traps with zero, one, or many reasons have occurred.
159 // It also tells whether zero or many recompilations have occurred.
160 // The associated trap histogram in the MDO itself tells whether
161 // traps are common or not. If a BCI shows that a trap X has
162 // occurred, and the MDO shows N occurrences of X, we make the
163 // simplifying assumption that all N occurrences can be blamed
164 // on that BCI.
165 int trap_state() {
166 return ((_header._struct._flags >> trap_shift) & trap_mask);
167 }
169 void set_trap_state(int new_state) {
170 assert(ProfileTraps, "used only under +ProfileTraps");
171 uint old_flags = (_header._struct._flags & flag_mask);
172 _header._struct._flags = (new_state << trap_shift) | old_flags;
173 }
175 u1 flags() {
176 return _header._struct._flags;
177 }
179 u2 bci() {
180 return _header._struct._bci;
181 }
183 void set_header(intptr_t value) {
184 _header._bits = value;
185 }
186 void release_set_header(intptr_t value) {
187 OrderAccess::release_store_ptr(&_header._bits, value);
188 }
189 intptr_t header() {
190 return _header._bits;
191 }
192 void set_cell_at(int index, intptr_t value) {
193 _cells[index] = value;
194 }
195 void release_set_cell_at(int index, intptr_t value) {
196 OrderAccess::release_store_ptr(&_cells[index], value);
197 }
198 intptr_t cell_at(int index) {
199 return _cells[index];
200 }
201 intptr_t* adr_cell_at(int index) {
202 return &_cells[index];
203 }
204 oop* adr_oop_at(int index) {
205 return (oop*)&(_cells[index]);
206 }
208 void set_flag_at(int flag_number) {
209 assert(flag_number < flag_limit, "oob");
210 _header._struct._flags |= (0x1 << flag_number);
211 }
212 bool flag_at(int flag_number) {
213 assert(flag_number < flag_limit, "oob");
214 return (_header._struct._flags & (0x1 << flag_number)) != 0;
215 }
217 // Low-level support for code generation.
218 static ByteSize header_offset() {
219 return byte_offset_of(DataLayout, _header);
220 }
221 static ByteSize tag_offset() {
222 return byte_offset_of(DataLayout, _header._struct._tag);
223 }
224 static ByteSize flags_offset() {
225 return byte_offset_of(DataLayout, _header._struct._flags);
226 }
227 static ByteSize bci_offset() {
228 return byte_offset_of(DataLayout, _header._struct._bci);
229 }
230 static ByteSize cell_offset(int index) {
231 return byte_offset_of(DataLayout, _cells) + in_ByteSize(index * cell_size);
232 }
233 // Return a value which, when or-ed as a byte into _flags, sets the flag.
234 static int flag_number_to_byte_constant(int flag_number) {
235 assert(0 <= flag_number && flag_number < flag_limit, "oob");
236 DataLayout temp; temp.set_header(0);
237 temp.set_flag_at(flag_number);
238 return temp._header._struct._flags;
239 }
240 // Return a value which, when or-ed as a word into _header, sets the flag.
241 static intptr_t flag_mask_to_header_mask(int byte_constant) {
242 DataLayout temp; temp.set_header(0);
243 temp._header._struct._flags = byte_constant;
244 return temp._header._bits;
245 }
247 // GC support
248 ProfileData* data_in();
249 void follow_weak_refs(BoolObjectClosure* cl);
250 };
253 // ProfileData class hierarchy
254 class ProfileData;
255 class BitData;
256 class CounterData;
257 class ReceiverTypeData;
258 class VirtualCallData;
259 class RetData;
260 class JumpData;
261 class BranchData;
262 class ArrayData;
263 class MultiBranchData;
264 class ArgInfoData;
267 // ProfileData
268 //
269 // A ProfileData object is created to refer to a section of profiling
270 // data in a structured way.
271 class ProfileData : public ResourceObj {
272 private:
273 #ifndef PRODUCT
274 enum {
275 tab_width_one = 16,
276 tab_width_two = 36
277 };
278 #endif // !PRODUCT
280 // This is a pointer to a section of profiling data.
281 DataLayout* _data;
283 protected:
284 DataLayout* data() { return _data; }
286 enum {
287 cell_size = DataLayout::cell_size
288 };
290 public:
291 // How many cells are in this?
292 virtual int cell_count() {
293 ShouldNotReachHere();
294 return -1;
295 }
297 // Return the size of this data.
298 int size_in_bytes() {
299 return DataLayout::compute_size_in_bytes(cell_count());
300 }
302 protected:
303 // Low-level accessors for underlying data
304 void set_intptr_at(int index, intptr_t value) {
305 assert(0 <= index && index < cell_count(), "oob");
306 data()->set_cell_at(index, value);
307 }
308 void release_set_intptr_at(int index, intptr_t value) {
309 assert(0 <= index && index < cell_count(), "oob");
310 data()->release_set_cell_at(index, value);
311 }
312 intptr_t intptr_at(int index) {
313 assert(0 <= index && index < cell_count(), "oob");
314 return data()->cell_at(index);
315 }
316 void set_uint_at(int index, uint value) {
317 set_intptr_at(index, (intptr_t) value);
318 }
319 void release_set_uint_at(int index, uint value) {
320 release_set_intptr_at(index, (intptr_t) value);
321 }
322 uint uint_at(int index) {
323 return (uint)intptr_at(index);
324 }
325 void set_int_at(int index, int value) {
326 set_intptr_at(index, (intptr_t) value);
327 }
328 void release_set_int_at(int index, int value) {
329 release_set_intptr_at(index, (intptr_t) value);
330 }
331 int int_at(int index) {
332 return (int)intptr_at(index);
333 }
334 int int_at_unchecked(int index) {
335 return (int)data()->cell_at(index);
336 }
337 void set_oop_at(int index, oop value) {
338 set_intptr_at(index, (intptr_t) value);
339 }
340 oop oop_at(int index) {
341 return (oop)intptr_at(index);
342 }
343 oop* adr_oop_at(int index) {
344 assert(0 <= index && index < cell_count(), "oob");
345 return data()->adr_oop_at(index);
346 }
348 void set_flag_at(int flag_number) {
349 data()->set_flag_at(flag_number);
350 }
351 bool flag_at(int flag_number) {
352 return data()->flag_at(flag_number);
353 }
355 // two convenient imports for use by subclasses:
356 static ByteSize cell_offset(int index) {
357 return DataLayout::cell_offset(index);
358 }
359 static int flag_number_to_byte_constant(int flag_number) {
360 return DataLayout::flag_number_to_byte_constant(flag_number);
361 }
363 ProfileData(DataLayout* data) {
364 _data = data;
365 }
367 public:
368 // Constructor for invalid ProfileData.
369 ProfileData();
371 u2 bci() {
372 return data()->bci();
373 }
375 address dp() {
376 return (address)_data;
377 }
379 int trap_state() {
380 return data()->trap_state();
381 }
382 void set_trap_state(int new_state) {
383 data()->set_trap_state(new_state);
384 }
386 // Type checking
387 virtual bool is_BitData() { return false; }
388 virtual bool is_CounterData() { return false; }
389 virtual bool is_JumpData() { return false; }
390 virtual bool is_ReceiverTypeData(){ return false; }
391 virtual bool is_VirtualCallData() { return false; }
392 virtual bool is_RetData() { return false; }
393 virtual bool is_BranchData() { return false; }
394 virtual bool is_ArrayData() { return false; }
395 virtual bool is_MultiBranchData() { return false; }
396 virtual bool is_ArgInfoData() { return false; }
399 BitData* as_BitData() {
400 assert(is_BitData(), "wrong type");
401 return is_BitData() ? (BitData*) this : NULL;
402 }
403 CounterData* as_CounterData() {
404 assert(is_CounterData(), "wrong type");
405 return is_CounterData() ? (CounterData*) this : NULL;
406 }
407 JumpData* as_JumpData() {
408 assert(is_JumpData(), "wrong type");
409 return is_JumpData() ? (JumpData*) this : NULL;
410 }
411 ReceiverTypeData* as_ReceiverTypeData() {
412 assert(is_ReceiverTypeData(), "wrong type");
413 return is_ReceiverTypeData() ? (ReceiverTypeData*)this : NULL;
414 }
415 VirtualCallData* as_VirtualCallData() {
416 assert(is_VirtualCallData(), "wrong type");
417 return is_VirtualCallData() ? (VirtualCallData*)this : NULL;
418 }
419 RetData* as_RetData() {
420 assert(is_RetData(), "wrong type");
421 return is_RetData() ? (RetData*) this : NULL;
422 }
423 BranchData* as_BranchData() {
424 assert(is_BranchData(), "wrong type");
425 return is_BranchData() ? (BranchData*) this : NULL;
426 }
427 ArrayData* as_ArrayData() {
428 assert(is_ArrayData(), "wrong type");
429 return is_ArrayData() ? (ArrayData*) this : NULL;
430 }
431 MultiBranchData* as_MultiBranchData() {
432 assert(is_MultiBranchData(), "wrong type");
433 return is_MultiBranchData() ? (MultiBranchData*)this : NULL;
434 }
435 ArgInfoData* as_ArgInfoData() {
436 assert(is_ArgInfoData(), "wrong type");
437 return is_ArgInfoData() ? (ArgInfoData*)this : NULL;
438 }
441 // Subclass specific initialization
442 virtual void post_initialize(BytecodeStream* stream, methodDataOop mdo) {}
444 // GC support
445 virtual void follow_contents() {}
446 virtual void oop_iterate(OopClosure* blk) {}
447 virtual void oop_iterate_m(OopClosure* blk, MemRegion mr) {}
448 virtual void adjust_pointers() {}
449 virtual void follow_weak_refs(BoolObjectClosure* is_alive_closure) {}
451 #ifndef SERIALGC
452 // Parallel old support
453 virtual void follow_contents(ParCompactionManager* cm) {}
454 virtual void update_pointers() {}
455 #endif // SERIALGC
457 // CI translation: ProfileData can represent both MethodDataOop data
458 // as well as CIMethodData data. This function is provided for translating
459 // an oop in a ProfileData to the ci equivalent. Generally speaking,
460 // most ProfileData don't require any translation, so we provide the null
461 // translation here, and the required translators are in the ci subclasses.
462 virtual void translate_from(ProfileData* data) {}
464 virtual void print_data_on(outputStream* st) {
465 ShouldNotReachHere();
466 }
468 #ifndef PRODUCT
469 void print_shared(outputStream* st, const char* name);
470 void tab(outputStream* st);
471 #endif
472 };
474 // BitData
475 //
476 // A BitData holds a flag or two in its header.
477 class BitData : public ProfileData {
478 protected:
479 enum {
480 // null_seen:
481 // saw a null operand (cast/aastore/instanceof)
482 null_seen_flag = DataLayout::first_flag + 0
483 };
484 enum { bit_cell_count = 0 }; // no additional data fields needed.
485 public:
486 BitData(DataLayout* layout) : ProfileData(layout) {
487 }
489 virtual bool is_BitData() { return true; }
491 static int static_cell_count() {
492 return bit_cell_count;
493 }
495 virtual int cell_count() {
496 return static_cell_count();
497 }
499 // Accessor
501 // The null_seen flag bit is specially known to the interpreter.
502 // Consulting it allows the compiler to avoid setting up null_check traps.
503 bool null_seen() { return flag_at(null_seen_flag); }
504 void set_null_seen() { set_flag_at(null_seen_flag); }
507 // Code generation support
508 static int null_seen_byte_constant() {
509 return flag_number_to_byte_constant(null_seen_flag);
510 }
512 static ByteSize bit_data_size() {
513 return cell_offset(bit_cell_count);
514 }
516 #ifndef PRODUCT
517 void print_data_on(outputStream* st);
518 #endif
519 };
521 // CounterData
522 //
523 // A CounterData corresponds to a simple counter.
524 class CounterData : public BitData {
525 protected:
526 enum {
527 count_off,
528 counter_cell_count
529 };
530 public:
531 CounterData(DataLayout* layout) : BitData(layout) {}
533 virtual bool is_CounterData() { return true; }
535 static int static_cell_count() {
536 return counter_cell_count;
537 }
539 virtual int cell_count() {
540 return static_cell_count();
541 }
543 // Direct accessor
544 uint count() {
545 return uint_at(count_off);
546 }
548 // Code generation support
549 static ByteSize count_offset() {
550 return cell_offset(count_off);
551 }
552 static ByteSize counter_data_size() {
553 return cell_offset(counter_cell_count);
554 }
556 void set_count(uint count) {
557 set_uint_at(count_off, count);
558 }
560 #ifndef PRODUCT
561 void print_data_on(outputStream* st);
562 #endif
563 };
565 // JumpData
566 //
567 // A JumpData is used to access profiling information for a direct
568 // branch. It is a counter, used for counting the number of branches,
569 // plus a data displacement, used for realigning the data pointer to
570 // the corresponding target bci.
571 class JumpData : public ProfileData {
572 protected:
573 enum {
574 taken_off_set,
575 displacement_off_set,
576 jump_cell_count
577 };
579 void set_displacement(int displacement) {
580 set_int_at(displacement_off_set, displacement);
581 }
583 public:
584 JumpData(DataLayout* layout) : ProfileData(layout) {
585 assert(layout->tag() == DataLayout::jump_data_tag ||
586 layout->tag() == DataLayout::branch_data_tag, "wrong type");
587 }
589 virtual bool is_JumpData() { return true; }
591 static int static_cell_count() {
592 return jump_cell_count;
593 }
595 virtual int cell_count() {
596 return static_cell_count();
597 }
599 // Direct accessor
600 uint taken() {
601 return uint_at(taken_off_set);
602 }
604 void set_taken(uint cnt) {
605 set_uint_at(taken_off_set, cnt);
606 }
608 // Saturating counter
609 uint inc_taken() {
610 uint cnt = taken() + 1;
611 // Did we wrap? Will compiler screw us??
612 if (cnt == 0) cnt--;
613 set_uint_at(taken_off_set, cnt);
614 return cnt;
615 }
617 int displacement() {
618 return int_at(displacement_off_set);
619 }
621 // Code generation support
622 static ByteSize taken_offset() {
623 return cell_offset(taken_off_set);
624 }
626 static ByteSize displacement_offset() {
627 return cell_offset(displacement_off_set);
628 }
630 // Specific initialization.
631 void post_initialize(BytecodeStream* stream, methodDataOop mdo);
633 #ifndef PRODUCT
634 void print_data_on(outputStream* st);
635 #endif
636 };
638 // ReceiverTypeData
639 //
640 // A ReceiverTypeData is used to access profiling information about a
641 // dynamic type check. It consists of a counter which counts the total times
642 // that the check is reached, and a series of (klassOop, count) pairs
643 // which are used to store a type profile for the receiver of the check.
644 class ReceiverTypeData : public CounterData {
645 protected:
646 enum {
647 receiver0_offset = counter_cell_count,
648 count0_offset,
649 receiver_type_row_cell_count = (count0_offset + 1) - receiver0_offset
650 };
652 public:
653 ReceiverTypeData(DataLayout* layout) : CounterData(layout) {
654 assert(layout->tag() == DataLayout::receiver_type_data_tag ||
655 layout->tag() == DataLayout::virtual_call_data_tag, "wrong type");
656 }
658 virtual bool is_ReceiverTypeData() { return true; }
660 static int static_cell_count() {
661 return counter_cell_count + (uint) TypeProfileWidth * receiver_type_row_cell_count;
662 }
664 virtual int cell_count() {
665 return static_cell_count();
666 }
668 // Direct accessors
669 static uint row_limit() {
670 return TypeProfileWidth;
671 }
672 static int receiver_cell_index(uint row) {
673 return receiver0_offset + row * receiver_type_row_cell_count;
674 }
675 static int receiver_count_cell_index(uint row) {
676 return count0_offset + row * receiver_type_row_cell_count;
677 }
679 // Get the receiver at row. The 'unchecked' version is needed by parallel old
680 // gc; it does not assert the receiver is a klass. During compaction of the
681 // perm gen, the klass may already have moved, so the is_klass() predicate
682 // would fail. The 'normal' version should be used whenever possible.
683 klassOop receiver_unchecked(uint row) {
684 assert(row < row_limit(), "oob");
685 oop recv = oop_at(receiver_cell_index(row));
686 return (klassOop)recv;
687 }
689 klassOop receiver(uint row) {
690 klassOop recv = receiver_unchecked(row);
691 assert(recv == NULL || ((oop)recv)->is_klass(), "wrong type");
692 return recv;
693 }
695 void set_receiver(uint row, oop p) {
696 assert((uint)row < row_limit(), "oob");
697 set_oop_at(receiver_cell_index(row), p);
698 }
700 uint receiver_count(uint row) {
701 assert(row < row_limit(), "oob");
702 return uint_at(receiver_count_cell_index(row));
703 }
705 void set_receiver_count(uint row, uint count) {
706 assert(row < row_limit(), "oob");
707 set_uint_at(receiver_count_cell_index(row), count);
708 }
710 void clear_row(uint row) {
711 assert(row < row_limit(), "oob");
712 // Clear total count - indicator of polymorphic call site.
713 // The site may look like as monomorphic after that but
714 // it allow to have more accurate profiling information because
715 // there was execution phase change since klasses were unloaded.
716 // If the site is still polymorphic then MDO will be updated
717 // to reflect it. But it could be the case that the site becomes
718 // only bimorphic. Then keeping total count not 0 will be wrong.
719 // Even if we use monomorphic (when it is not) for compilation
720 // we will only have trap, deoptimization and recompile again
721 // with updated MDO after executing method in Interpreter.
722 // An additional receiver will be recorded in the cleaned row
723 // during next call execution.
724 //
725 // Note: our profiling logic works with empty rows in any slot.
726 // We do sorting a profiling info (ciCallProfile) for compilation.
727 //
728 set_count(0);
729 set_receiver(row, NULL);
730 set_receiver_count(row, 0);
731 }
733 // Code generation support
734 static ByteSize receiver_offset(uint row) {
735 return cell_offset(receiver_cell_index(row));
736 }
737 static ByteSize receiver_count_offset(uint row) {
738 return cell_offset(receiver_count_cell_index(row));
739 }
740 static ByteSize receiver_type_data_size() {
741 return cell_offset(static_cell_count());
742 }
744 // GC support
745 virtual void follow_contents();
746 virtual void oop_iterate(OopClosure* blk);
747 virtual void oop_iterate_m(OopClosure* blk, MemRegion mr);
748 virtual void adjust_pointers();
749 virtual void follow_weak_refs(BoolObjectClosure* is_alive_closure);
751 #ifndef SERIALGC
752 // Parallel old support
753 virtual void follow_contents(ParCompactionManager* cm);
754 virtual void update_pointers();
755 #endif // SERIALGC
757 oop* adr_receiver(uint row) {
758 return adr_oop_at(receiver_cell_index(row));
759 }
761 #ifndef PRODUCT
762 void print_receiver_data_on(outputStream* st);
763 void print_data_on(outputStream* st);
764 #endif
765 };
767 // VirtualCallData
768 //
769 // A VirtualCallData is used to access profiling information about a
770 // virtual call. For now, it has nothing more than a ReceiverTypeData.
771 class VirtualCallData : public ReceiverTypeData {
772 public:
773 VirtualCallData(DataLayout* layout) : ReceiverTypeData(layout) {
774 assert(layout->tag() == DataLayout::virtual_call_data_tag, "wrong type");
775 }
777 virtual bool is_VirtualCallData() { return true; }
779 static int static_cell_count() {
780 // At this point we could add more profile state, e.g., for arguments.
781 // But for now it's the same size as the base record type.
782 return ReceiverTypeData::static_cell_count();
783 }
785 virtual int cell_count() {
786 return static_cell_count();
787 }
789 // Direct accessors
790 static ByteSize virtual_call_data_size() {
791 return cell_offset(static_cell_count());
792 }
794 #ifndef PRODUCT
795 void print_data_on(outputStream* st);
796 #endif
797 };
799 // RetData
800 //
801 // A RetData is used to access profiling information for a ret bytecode.
802 // It is composed of a count of the number of times that the ret has
803 // been executed, followed by a series of triples of the form
804 // (bci, count, di) which count the number of times that some bci was the
805 // target of the ret and cache a corresponding data displacement.
806 class RetData : public CounterData {
807 protected:
808 enum {
809 bci0_offset = counter_cell_count,
810 count0_offset,
811 displacement0_offset,
812 ret_row_cell_count = (displacement0_offset + 1) - bci0_offset
813 };
815 void set_bci(uint row, int bci) {
816 assert((uint)row < row_limit(), "oob");
817 set_int_at(bci0_offset + row * ret_row_cell_count, bci);
818 }
819 void release_set_bci(uint row, int bci) {
820 assert((uint)row < row_limit(), "oob");
821 // 'release' when setting the bci acts as a valid flag for other
822 // threads wrt bci_count and bci_displacement.
823 release_set_int_at(bci0_offset + row * ret_row_cell_count, bci);
824 }
825 void set_bci_count(uint row, uint count) {
826 assert((uint)row < row_limit(), "oob");
827 set_uint_at(count0_offset + row * ret_row_cell_count, count);
828 }
829 void set_bci_displacement(uint row, int disp) {
830 set_int_at(displacement0_offset + row * ret_row_cell_count, disp);
831 }
833 public:
834 RetData(DataLayout* layout) : CounterData(layout) {
835 assert(layout->tag() == DataLayout::ret_data_tag, "wrong type");
836 }
838 virtual bool is_RetData() { return true; }
840 enum {
841 no_bci = -1 // value of bci when bci1/2 are not in use.
842 };
844 static int static_cell_count() {
845 return counter_cell_count + (uint) BciProfileWidth * ret_row_cell_count;
846 }
848 virtual int cell_count() {
849 return static_cell_count();
850 }
852 static uint row_limit() {
853 return BciProfileWidth;
854 }
855 static int bci_cell_index(uint row) {
856 return bci0_offset + row * ret_row_cell_count;
857 }
858 static int bci_count_cell_index(uint row) {
859 return count0_offset + row * ret_row_cell_count;
860 }
861 static int bci_displacement_cell_index(uint row) {
862 return displacement0_offset + row * ret_row_cell_count;
863 }
865 // Direct accessors
866 int bci(uint row) {
867 return int_at(bci_cell_index(row));
868 }
869 uint bci_count(uint row) {
870 return uint_at(bci_count_cell_index(row));
871 }
872 int bci_displacement(uint row) {
873 return int_at(bci_displacement_cell_index(row));
874 }
876 // Interpreter Runtime support
877 address fixup_ret(int return_bci, methodDataHandle mdo);
879 // Code generation support
880 static ByteSize bci_offset(uint row) {
881 return cell_offset(bci_cell_index(row));
882 }
883 static ByteSize bci_count_offset(uint row) {
884 return cell_offset(bci_count_cell_index(row));
885 }
886 static ByteSize bci_displacement_offset(uint row) {
887 return cell_offset(bci_displacement_cell_index(row));
888 }
890 // Specific initialization.
891 void post_initialize(BytecodeStream* stream, methodDataOop mdo);
893 #ifndef PRODUCT
894 void print_data_on(outputStream* st);
895 #endif
896 };
898 // BranchData
899 //
900 // A BranchData is used to access profiling data for a two-way branch.
901 // It consists of taken and not_taken counts as well as a data displacement
902 // for the taken case.
903 class BranchData : public JumpData {
904 protected:
905 enum {
906 not_taken_off_set = jump_cell_count,
907 branch_cell_count
908 };
910 void set_displacement(int displacement) {
911 set_int_at(displacement_off_set, displacement);
912 }
914 public:
915 BranchData(DataLayout* layout) : JumpData(layout) {
916 assert(layout->tag() == DataLayout::branch_data_tag, "wrong type");
917 }
919 virtual bool is_BranchData() { return true; }
921 static int static_cell_count() {
922 return branch_cell_count;
923 }
925 virtual int cell_count() {
926 return static_cell_count();
927 }
929 // Direct accessor
930 uint not_taken() {
931 return uint_at(not_taken_off_set);
932 }
934 void set_not_taken(uint cnt) {
935 set_uint_at(not_taken_off_set, cnt);
936 }
938 uint inc_not_taken() {
939 uint cnt = not_taken() + 1;
940 // Did we wrap? Will compiler screw us??
941 if (cnt == 0) cnt--;
942 set_uint_at(not_taken_off_set, cnt);
943 return cnt;
944 }
946 // Code generation support
947 static ByteSize not_taken_offset() {
948 return cell_offset(not_taken_off_set);
949 }
950 static ByteSize branch_data_size() {
951 return cell_offset(branch_cell_count);
952 }
954 // Specific initialization.
955 void post_initialize(BytecodeStream* stream, methodDataOop mdo);
957 #ifndef PRODUCT
958 void print_data_on(outputStream* st);
959 #endif
960 };
962 // ArrayData
963 //
964 // A ArrayData is a base class for accessing profiling data which does
965 // not have a statically known size. It consists of an array length
966 // and an array start.
967 class ArrayData : public ProfileData {
968 protected:
969 friend class DataLayout;
971 enum {
972 array_len_off_set,
973 array_start_off_set
974 };
976 uint array_uint_at(int index) {
977 int aindex = index + array_start_off_set;
978 return uint_at(aindex);
979 }
980 int array_int_at(int index) {
981 int aindex = index + array_start_off_set;
982 return int_at(aindex);
983 }
984 oop array_oop_at(int index) {
985 int aindex = index + array_start_off_set;
986 return oop_at(aindex);
987 }
988 void array_set_int_at(int index, int value) {
989 int aindex = index + array_start_off_set;
990 set_int_at(aindex, value);
991 }
993 // Code generation support for subclasses.
994 static ByteSize array_element_offset(int index) {
995 return cell_offset(array_start_off_set + index);
996 }
998 public:
999 ArrayData(DataLayout* layout) : ProfileData(layout) {}
1001 virtual bool is_ArrayData() { return true; }
1003 static int static_cell_count() {
1004 return -1;
1005 }
1007 int array_len() {
1008 return int_at_unchecked(array_len_off_set);
1009 }
1011 virtual int cell_count() {
1012 return array_len() + 1;
1013 }
1015 // Code generation support
1016 static ByteSize array_len_offset() {
1017 return cell_offset(array_len_off_set);
1018 }
1019 static ByteSize array_start_offset() {
1020 return cell_offset(array_start_off_set);
1021 }
1022 };
1024 // MultiBranchData
1025 //
1026 // A MultiBranchData is used to access profiling information for
1027 // a multi-way branch (*switch bytecodes). It consists of a series
1028 // of (count, displacement) pairs, which count the number of times each
1029 // case was taken and specify the data displacment for each branch target.
1030 class MultiBranchData : public ArrayData {
1031 protected:
1032 enum {
1033 default_count_off_set,
1034 default_disaplacement_off_set,
1035 case_array_start
1036 };
1037 enum {
1038 relative_count_off_set,
1039 relative_displacement_off_set,
1040 per_case_cell_count
1041 };
1043 void set_default_displacement(int displacement) {
1044 array_set_int_at(default_disaplacement_off_set, displacement);
1045 }
1046 void set_displacement_at(int index, int displacement) {
1047 array_set_int_at(case_array_start +
1048 index * per_case_cell_count +
1049 relative_displacement_off_set,
1050 displacement);
1051 }
1053 public:
1054 MultiBranchData(DataLayout* layout) : ArrayData(layout) {
1055 assert(layout->tag() == DataLayout::multi_branch_data_tag, "wrong type");
1056 }
1058 virtual bool is_MultiBranchData() { return true; }
1060 static int compute_cell_count(BytecodeStream* stream);
1062 int number_of_cases() {
1063 int alen = array_len() - 2; // get rid of default case here.
1064 assert(alen % per_case_cell_count == 0, "must be even");
1065 return (alen / per_case_cell_count);
1066 }
1068 uint default_count() {
1069 return array_uint_at(default_count_off_set);
1070 }
1071 int default_displacement() {
1072 return array_int_at(default_disaplacement_off_set);
1073 }
1075 uint count_at(int index) {
1076 return array_uint_at(case_array_start +
1077 index * per_case_cell_count +
1078 relative_count_off_set);
1079 }
1080 int displacement_at(int index) {
1081 return array_int_at(case_array_start +
1082 index * per_case_cell_count +
1083 relative_displacement_off_set);
1084 }
1086 // Code generation support
1087 static ByteSize default_count_offset() {
1088 return array_element_offset(default_count_off_set);
1089 }
1090 static ByteSize default_displacement_offset() {
1091 return array_element_offset(default_disaplacement_off_set);
1092 }
1093 static ByteSize case_count_offset(int index) {
1094 return case_array_offset() +
1095 (per_case_size() * index) +
1096 relative_count_offset();
1097 }
1098 static ByteSize case_array_offset() {
1099 return array_element_offset(case_array_start);
1100 }
1101 static ByteSize per_case_size() {
1102 return in_ByteSize(per_case_cell_count) * cell_size;
1103 }
1104 static ByteSize relative_count_offset() {
1105 return in_ByteSize(relative_count_off_set) * cell_size;
1106 }
1107 static ByteSize relative_displacement_offset() {
1108 return in_ByteSize(relative_displacement_off_set) * cell_size;
1109 }
1111 // Specific initialization.
1112 void post_initialize(BytecodeStream* stream, methodDataOop mdo);
1114 #ifndef PRODUCT
1115 void print_data_on(outputStream* st);
1116 #endif
1117 };
1119 class ArgInfoData : public ArrayData {
1121 public:
1122 ArgInfoData(DataLayout* layout) : ArrayData(layout) {
1123 assert(layout->tag() == DataLayout::arg_info_data_tag, "wrong type");
1124 }
1126 virtual bool is_ArgInfoData() { return true; }
1129 int number_of_args() {
1130 return array_len();
1131 }
1133 uint arg_modified(int arg) {
1134 return array_uint_at(arg);
1135 }
1137 void set_arg_modified(int arg, uint val) {
1138 array_set_int_at(arg, val);
1139 }
1141 #ifndef PRODUCT
1142 void print_data_on(outputStream* st);
1143 #endif
1144 };
1146 // methodDataOop
1147 //
1148 // A methodDataOop holds information which has been collected about
1149 // a method. Its layout looks like this:
1150 //
1151 // -----------------------------
1152 // | header |
1153 // | klass |
1154 // -----------------------------
1155 // | method |
1156 // | size of the methodDataOop |
1157 // -----------------------------
1158 // | Data entries... |
1159 // | (variable size) |
1160 // | |
1161 // . .
1162 // . .
1163 // . .
1164 // | |
1165 // -----------------------------
1166 //
1167 // The data entry area is a heterogeneous array of DataLayouts. Each
1168 // DataLayout in the array corresponds to a specific bytecode in the
1169 // method. The entries in the array are sorted by the corresponding
1170 // bytecode. Access to the data is via resource-allocated ProfileData,
1171 // which point to the underlying blocks of DataLayout structures.
1172 //
1173 // During interpretation, if profiling in enabled, the interpreter
1174 // maintains a method data pointer (mdp), which points at the entry
1175 // in the array corresponding to the current bci. In the course of
1176 // intepretation, when a bytecode is encountered that has profile data
1177 // associated with it, the entry pointed to by mdp is updated, then the
1178 // mdp is adjusted to point to the next appropriate DataLayout. If mdp
1179 // is NULL to begin with, the interpreter assumes that the current method
1180 // is not (yet) being profiled.
1181 //
1182 // In methodDataOop parlance, "dp" is a "data pointer", the actual address
1183 // of a DataLayout element. A "di" is a "data index", the offset in bytes
1184 // from the base of the data entry array. A "displacement" is the byte offset
1185 // in certain ProfileData objects that indicate the amount the mdp must be
1186 // adjusted in the event of a change in control flow.
1187 //
1189 class methodDataOopDesc : public oopDesc {
1190 friend class VMStructs;
1191 private:
1192 friend class ProfileData;
1194 // Back pointer to the methodOop
1195 methodOop _method;
1197 // Size of this oop in bytes
1198 int _size;
1200 // Cached hint for bci_to_dp and bci_to_data
1201 int _hint_di;
1203 // Whole-method sticky bits and flags
1204 public:
1205 enum {
1206 _trap_hist_limit = 17, // decoupled from Deoptimization::Reason_LIMIT
1207 _trap_hist_mask = max_jubyte,
1208 _extra_data_count = 4 // extra DataLayout headers, for trap history
1209 }; // Public flag values
1210 private:
1211 uint _nof_decompiles; // count of all nmethod removals
1212 uint _nof_overflow_recompiles; // recompile count, excluding recomp. bits
1213 uint _nof_overflow_traps; // trap count, excluding _trap_hist
1214 union {
1215 intptr_t _align;
1216 u1 _array[_trap_hist_limit];
1217 } _trap_hist;
1219 // Support for interprocedural escape analysis, from Thomas Kotzmann.
1220 intx _eflags; // flags on escape information
1221 intx _arg_local; // bit set of non-escaping arguments
1222 intx _arg_stack; // bit set of stack-allocatable arguments
1223 intx _arg_returned; // bit set of returned arguments
1225 int _creation_mileage; // method mileage at MDO creation
1227 // How many invocations has this MDO seen?
1228 // These counters are used to determine the exact age of MDO.
1229 // We need those because in tiered a method can be concurrently
1230 // executed at different levels.
1231 InvocationCounter _invocation_counter;
1232 // Same for backedges.
1233 InvocationCounter _backedge_counter;
1234 // Counter values at the time profiling started.
1235 int _invocation_counter_start;
1236 int _backedge_counter_start;
1237 // Number of loops and blocks is computed when compiling the first
1238 // time with C1. It is used to determine if method is trivial.
1239 short _num_loops;
1240 short _num_blocks;
1241 // Highest compile level this method has ever seen.
1242 u1 _highest_comp_level;
1243 // Same for OSR level
1244 u1 _highest_osr_comp_level;
1245 // Does this method contain anything worth profiling?
1246 bool _would_profile;
1248 // Size of _data array in bytes. (Excludes header and extra_data fields.)
1249 int _data_size;
1251 // Beginning of the data entries
1252 intptr_t _data[1];
1254 // Helper for size computation
1255 static int compute_data_size(BytecodeStream* stream);
1256 static int bytecode_cell_count(Bytecodes::Code code);
1257 enum { no_profile_data = -1, variable_cell_count = -2 };
1259 // Helper for initialization
1260 DataLayout* data_layout_at(int data_index) {
1261 assert(data_index % sizeof(intptr_t) == 0, "unaligned");
1262 return (DataLayout*) (((address)_data) + data_index);
1263 }
1265 // Initialize an individual data segment. Returns the size of
1266 // the segment in bytes.
1267 int initialize_data(BytecodeStream* stream, int data_index);
1269 // Helper for data_at
1270 DataLayout* limit_data_position() {
1271 return (DataLayout*)((address)data_base() + _data_size);
1272 }
1273 bool out_of_bounds(int data_index) {
1274 return data_index >= data_size();
1275 }
1277 // Give each of the data entries a chance to perform specific
1278 // data initialization.
1279 void post_initialize(BytecodeStream* stream);
1281 // hint accessors
1282 int hint_di() const { return _hint_di; }
1283 void set_hint_di(int di) {
1284 assert(!out_of_bounds(di), "hint_di out of bounds");
1285 _hint_di = di;
1286 }
1287 ProfileData* data_before(int bci) {
1288 // avoid SEGV on this edge case
1289 if (data_size() == 0)
1290 return NULL;
1291 int hint = hint_di();
1292 if (data_layout_at(hint)->bci() <= bci)
1293 return data_at(hint);
1294 return first_data();
1295 }
1297 // What is the index of the first data entry?
1298 int first_di() { return 0; }
1300 // Find or create an extra ProfileData:
1301 ProfileData* bci_to_extra_data(int bci, bool create_if_missing);
1303 // return the argument info cell
1304 ArgInfoData *arg_info();
1306 public:
1307 static int header_size() {
1308 return sizeof(methodDataOopDesc)/wordSize;
1309 }
1311 // Compute the size of a methodDataOop before it is created.
1312 static int compute_allocation_size_in_bytes(methodHandle method);
1313 static int compute_allocation_size_in_words(methodHandle method);
1314 static int compute_extra_data_count(int data_size, int empty_bc_count);
1316 // Determine if a given bytecode can have profile information.
1317 static bool bytecode_has_profile(Bytecodes::Code code) {
1318 return bytecode_cell_count(code) != no_profile_data;
1319 }
1321 // Perform initialization of a new methodDataOop
1322 void initialize(methodHandle method);
1324 // My size
1325 int object_size_in_bytes() { return _size; }
1326 int object_size() {
1327 return align_object_size(align_size_up(_size, BytesPerWord)/BytesPerWord);
1328 }
1330 int creation_mileage() const { return _creation_mileage; }
1331 void set_creation_mileage(int x) { _creation_mileage = x; }
1333 int invocation_count() {
1334 if (invocation_counter()->carry()) {
1335 return InvocationCounter::count_limit;
1336 }
1337 return invocation_counter()->count();
1338 }
1339 int backedge_count() {
1340 if (backedge_counter()->carry()) {
1341 return InvocationCounter::count_limit;
1342 }
1343 return backedge_counter()->count();
1344 }
1346 int invocation_count_start() {
1347 if (invocation_counter()->carry()) {
1348 return 0;
1349 }
1350 return _invocation_counter_start;
1351 }
1353 int backedge_count_start() {
1354 if (backedge_counter()->carry()) {
1355 return 0;
1356 }
1357 return _backedge_counter_start;
1358 }
1360 int invocation_count_delta() { return invocation_count() - invocation_count_start(); }
1361 int backedge_count_delta() { return backedge_count() - backedge_count_start(); }
1363 void reset_start_counters() {
1364 _invocation_counter_start = invocation_count();
1365 _backedge_counter_start = backedge_count();
1366 }
1368 InvocationCounter* invocation_counter() { return &_invocation_counter; }
1369 InvocationCounter* backedge_counter() { return &_backedge_counter; }
1371 void set_would_profile(bool p) { _would_profile = p; }
1372 bool would_profile() const { return _would_profile; }
1374 int highest_comp_level() { return _highest_comp_level; }
1375 void set_highest_comp_level(int level) { _highest_comp_level = level; }
1376 int highest_osr_comp_level() { return _highest_osr_comp_level; }
1377 void set_highest_osr_comp_level(int level) { _highest_osr_comp_level = level; }
1379 int num_loops() const { return _num_loops; }
1380 void set_num_loops(int n) { _num_loops = n; }
1381 int num_blocks() const { return _num_blocks; }
1382 void set_num_blocks(int n) { _num_blocks = n; }
1384 bool is_mature() const; // consult mileage and ProfileMaturityPercentage
1385 static int mileage_of(methodOop m);
1387 // Support for interprocedural escape analysis, from Thomas Kotzmann.
1388 enum EscapeFlag {
1389 estimated = 1 << 0,
1390 return_local = 1 << 1,
1391 return_allocated = 1 << 2,
1392 allocated_escapes = 1 << 3,
1393 unknown_modified = 1 << 4
1394 };
1396 intx eflags() { return _eflags; }
1397 intx arg_local() { return _arg_local; }
1398 intx arg_stack() { return _arg_stack; }
1399 intx arg_returned() { return _arg_returned; }
1400 uint arg_modified(int a) { ArgInfoData *aid = arg_info();
1401 assert(a >= 0 && a < aid->number_of_args(), "valid argument number");
1402 return aid->arg_modified(a); }
1404 void set_eflags(intx v) { _eflags = v; }
1405 void set_arg_local(intx v) { _arg_local = v; }
1406 void set_arg_stack(intx v) { _arg_stack = v; }
1407 void set_arg_returned(intx v) { _arg_returned = v; }
1408 void set_arg_modified(int a, uint v) { ArgInfoData *aid = arg_info();
1409 assert(a >= 0 && a < aid->number_of_args(), "valid argument number");
1411 aid->set_arg_modified(a, v); }
1413 void clear_escape_info() { _eflags = _arg_local = _arg_stack = _arg_returned = 0; }
1415 // Location and size of data area
1416 address data_base() const {
1417 return (address) _data;
1418 }
1419 int data_size() {
1420 return _data_size;
1421 }
1423 // Accessors
1424 methodOop method() { return _method; }
1426 // Get the data at an arbitrary (sort of) data index.
1427 ProfileData* data_at(int data_index);
1429 // Walk through the data in order.
1430 ProfileData* first_data() { return data_at(first_di()); }
1431 ProfileData* next_data(ProfileData* current);
1432 bool is_valid(ProfileData* current) { return current != NULL; }
1434 // Convert a dp (data pointer) to a di (data index).
1435 int dp_to_di(address dp) {
1436 return dp - ((address)_data);
1437 }
1439 address di_to_dp(int di) {
1440 return (address)data_layout_at(di);
1441 }
1443 // bci to di/dp conversion.
1444 address bci_to_dp(int bci);
1445 int bci_to_di(int bci) {
1446 return dp_to_di(bci_to_dp(bci));
1447 }
1449 // Get the data at an arbitrary bci, or NULL if there is none.
1450 ProfileData* bci_to_data(int bci);
1452 // Same, but try to create an extra_data record if one is needed:
1453 ProfileData* allocate_bci_to_data(int bci) {
1454 ProfileData* data = bci_to_data(bci);
1455 return (data != NULL) ? data : bci_to_extra_data(bci, true);
1456 }
1458 // Add a handful of extra data records, for trap tracking.
1459 DataLayout* extra_data_base() { return limit_data_position(); }
1460 DataLayout* extra_data_limit() { return (DataLayout*)((address)this + object_size_in_bytes()); }
1461 int extra_data_size() { return (address)extra_data_limit()
1462 - (address)extra_data_base(); }
1463 static DataLayout* next_extra(DataLayout* dp) { return (DataLayout*)((address)dp + in_bytes(DataLayout::cell_offset(0))); }
1465 // Return (uint)-1 for overflow.
1466 uint trap_count(int reason) const {
1467 assert((uint)reason < _trap_hist_limit, "oob");
1468 return (int)((_trap_hist._array[reason]+1) & _trap_hist_mask) - 1;
1469 }
1470 // For loops:
1471 static uint trap_reason_limit() { return _trap_hist_limit; }
1472 static uint trap_count_limit() { return _trap_hist_mask; }
1473 uint inc_trap_count(int reason) {
1474 // Count another trap, anywhere in this method.
1475 assert(reason >= 0, "must be single trap");
1476 if ((uint)reason < _trap_hist_limit) {
1477 uint cnt1 = 1 + _trap_hist._array[reason];
1478 if ((cnt1 & _trap_hist_mask) != 0) { // if no counter overflow...
1479 _trap_hist._array[reason] = cnt1;
1480 return cnt1;
1481 } else {
1482 return _trap_hist_mask + (++_nof_overflow_traps);
1483 }
1484 } else {
1485 // Could not represent the count in the histogram.
1486 return (++_nof_overflow_traps);
1487 }
1488 }
1490 uint overflow_trap_count() const {
1491 return _nof_overflow_traps;
1492 }
1493 uint overflow_recompile_count() const {
1494 return _nof_overflow_recompiles;
1495 }
1496 void inc_overflow_recompile_count() {
1497 _nof_overflow_recompiles += 1;
1498 }
1499 uint decompile_count() const {
1500 return _nof_decompiles;
1501 }
1502 void inc_decompile_count() {
1503 _nof_decompiles += 1;
1504 if (decompile_count() > (uint)PerMethodRecompilationCutoff) {
1505 method()->set_not_compilable(CompLevel_full_optimization);
1506 }
1507 }
1509 // Support for code generation
1510 static ByteSize data_offset() {
1511 return byte_offset_of(methodDataOopDesc, _data[0]);
1512 }
1514 static ByteSize invocation_counter_offset() {
1515 return byte_offset_of(methodDataOopDesc, _invocation_counter);
1516 }
1517 static ByteSize backedge_counter_offset() {
1518 return byte_offset_of(methodDataOopDesc, _backedge_counter);
1519 }
1521 // GC support
1522 oop* adr_method() const { return (oop*)&_method; }
1523 bool object_is_parsable() const { return _size != 0; }
1524 void set_object_is_parsable(int object_size_in_bytes) { _size = object_size_in_bytes; }
1526 #ifndef PRODUCT
1527 // printing support for method data
1528 void print_data_on(outputStream* st);
1529 #endif
1531 // verification
1532 void verify_data_on(outputStream* st);
1533 };
1535 #endif // SHARE_VM_OOPS_METHODDATAOOP_HPP