1 /*
  2  * Copyright (c) 1998, 2024, 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.
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 23  */
 24 
 25 #ifndef SHARE_COMPILER_OOPMAP_HPP
 26 #define SHARE_COMPILER_OOPMAP_HPP
 27 
 28 #include "code/compressedStream.hpp"
 29 #include "code/vmreg.hpp"
 30 #include "memory/allocation.hpp"
 31 #include "memory/iterator.hpp"
 32 #include "oops/oopsHierarchy.hpp"
 33 #include "utilities/checkedCast.hpp"
 34 #include "utilities/growableArray.hpp"
 35 
 36 // Interface for generating the frame map for compiled code.  A frame map
 37 // describes for a specific pc whether each register and frame stack slot is:
 38 //   Oop         - A GC root for current frame
 39 //   Dead        - Dead; can be Zapped for debugging
 40 //   CalleeXX    - Callee saved; also describes which caller register is saved
 41 //   DerivedXX   - A derived oop; original oop is described.
 42 //
 43 // OopMapValue describes a single OopMap entry
 44 
 45 enum class DerivedPointerIterationMode;
 46 class frame;
 47 class RegisterMap;
 48 class OopClosure;
 49 class CodeBlob;
 50 class ImmutableOopMap;
 51 
 52 enum class derived_base : intptr_t {};
 53 enum class derived_pointer : intptr_t {};
 54 
 55 class OopMapValue: public StackObj {
 56   friend class VMStructs;
 57 private:
 58   unsigned short _value;
 59   unsigned short value() const                      { return _value; }
 60   void set_value(unsigned short value)              { _value = value; }
 61   short _content_reg;
 62 
 63 public:
 64   // Constants
 65   enum { type_bits                = 2,
 66          register_bits            = BitsPerShort - type_bits };
 67 
 68   enum { type_shift               = 0,
 69          register_shift           = type_bits };
 70 
 71   enum { type_mask                = right_n_bits(type_bits),
 72          type_mask_in_place       = type_mask << type_shift,
 73          register_mask            = right_n_bits(register_bits),
 74          register_mask_in_place   = register_mask << register_shift };
 75 
 76   enum oop_types {
 77          oop_value,
 78          narrowoop_value,
 79          callee_saved_value,
 80          derived_oop_value,
 81          unused_value = -1          // Only used as a sentinel value
 82   };
 83 
 84   // Constructors
 85   OopMapValue () { set_value(0); set_content_reg(VMRegImpl::Bad()); }
 86   OopMapValue (VMReg reg, oop_types t, VMReg reg2) {
 87     set_reg_type(reg, t);
 88     set_content_reg(reg2);
 89   }
 90 
 91  private:
 92   void set_reg_type(VMReg p, oop_types t) {
 93     set_value(checked_cast<unsigned short>((p->value() << register_shift) | t));
 94     assert(reg() == p, "sanity check" );
 95     assert(type() == t, "sanity check" );
 96   }
 97 
 98   void set_content_reg(VMReg r) {
 99     if (is_callee_saved()) {
100       // This can never be a stack location, so we don't need to transform it.
101       assert(r->is_reg(), "Trying to callee save a stack location");
102     } else if (is_derived_oop()) {
103       assert (r->is_valid(), "must have a valid VMReg");
104     } else {
105       assert (!r->is_valid(), "valid VMReg not allowed");
106     }
107     _content_reg = checked_cast<short>(r->value());
108   }
109 
110  public:
111   // Archiving
112   void write_on(CompressedWriteStream* stream) {
113     stream->write_int(value());
114     if(is_callee_saved() || is_derived_oop()) {
115       stream->write_int(checked_cast<int>(content_reg()->value()));
116     }
117   }
118 
119   void read_from(CompressedReadStream* stream) {
120     set_value(checked_cast<unsigned short>(stream->read_int()));
121     if (is_callee_saved() || is_derived_oop()) {
122       set_content_reg(VMRegImpl::as_VMReg(stream->read_int(), true));
123     }
124   }
125 
126   // Querying
127   bool is_oop()               { return mask_bits(value(), type_mask_in_place) == oop_value; }
128   bool is_narrowoop()         { return mask_bits(value(), type_mask_in_place) == narrowoop_value; }
129   bool is_callee_saved()      { return mask_bits(value(), type_mask_in_place) == callee_saved_value; }
130   bool is_derived_oop()       { return mask_bits(value(), type_mask_in_place) == derived_oop_value; }
131 
132   VMReg reg() const { return VMRegImpl::as_VMReg(checked_cast<int>(mask_bits(value(), register_mask_in_place) >> register_shift)); }
133   oop_types type() const      { return (oop_types)mask_bits(value(), type_mask_in_place); }
134 
135   static bool legal_vm_reg_name(VMReg p) {
136     return (p->value()  == (p->value() & register_mask));
137   }
138 
139   VMReg content_reg() const       { return VMRegImpl::as_VMReg(_content_reg, true); }
140 
141   // Returns offset from sp.
142   int stack_offset() {
143     assert(reg()->is_stack(), "must be stack location");
144     return reg()->reg2stack();
145   }
146 
147   void print_on(outputStream* st) const;
148   void print() const;
149 };
150 
151 
152 class OopMap: public ResourceObj {
153   friend class OopMapStream;
154   friend class VMStructs;
155   friend class OopMapSet;
156   friend class OopMapSort;
157   friend class SCCReader;
158  private:
159   int  _pc_offset; // offset in the code that this OopMap corresponds to
160   int  _omv_count; // number of OopMapValues in the stream
161   int  _num_oops;  // number of oops
162   int  _index;     // index in OopMapSet
163   bool _has_derived_oops;
164   CompressedWriteStream* _write_stream;
165 
166   debug_only( OopMapValue::oop_types* _locs_used; int _locs_length;)
167 
168   // Accessors
169   int omv_count() const                       { return _omv_count; }
170   void set_omv_count(int value)               { _omv_count = value; }
171   void increment_count()                      { _omv_count++; }
172   void increment_num_oops()                   { _num_oops++; }
173   void set_has_derived_oops(bool value)       { _has_derived_oops = value; }
174   CompressedWriteStream* write_stream() const { return _write_stream; }
175   void set_write_stream(CompressedWriteStream* value) { _write_stream = value; }
176 
177   enum DeepCopyToken { _deep_copy_token };
178   OopMap(DeepCopyToken, OopMap* source);  // used only by deep_copy
179 
180   void set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional);
181 
182  public:
183   OopMap(int frame_size, int arg_count);
184   OopMap(int data_size);
185 
186   // pc-offset handling
187   int offset() const     { return _pc_offset; }
188   void set_offset(int o) { _pc_offset = o; }
189   int count() const { return _omv_count; }
190   int data_size() const  { return write_stream()->position(); }
191   address data() const { return write_stream()->buffer(); }
192   int num_oops() const { return _num_oops; }
193   bool has_derived_oops() const { return _has_derived_oops; }
194   int index() const { return _index; }
195 
196   // Construction
197   // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
198   // slots to hold 4-byte values like ints and floats in the LP64 build.
199   void set_oop  ( VMReg local);
200   void set_narrowoop(VMReg local);
201   void set_callee_saved( VMReg local, VMReg caller_machine_register );
202   void set_derived_oop ( VMReg local, VMReg derived_from_local_register );
203 
204   int heap_size() const;
205   void copy_data_to(address addr) const;
206   void copy_and_sort_data_to(address addr) const;
207   OopMap* deep_copy();
208 
209   bool legal_vm_reg_name(VMReg local) {
210      return OopMapValue::legal_vm_reg_name(local);
211   }
212 
213   // Printing
214   void print_on(outputStream* st) const;
215   void print() const;
216   bool equals(const OopMap* other) const;
217 };
218 
219 class OopMapSet : public ResourceObj {
220   friend class VMStructs;
221   friend class SCCReader;
222  private:
223   GrowableArray<OopMap*> _list;
224 
225   int add(OopMap* value) { return _list.append(value); }
226 
227  public:
228   OopMapSet();
229   OopMapSet(int size);
230 
231   // returns the number of OopMaps in this OopMapSet
232   int size() const            { return _list.length(); }
233   // returns the OopMap at a given index
234   OopMap* at(int index) const { return _list.at(index); }
235 
236   // Collect OopMaps.
237   int add_gc_map(int pc, OopMap* map);
238 
239   // Methods oops_do() and all_do() filter out nullptr oops and
240   // oop == CompressedOops::base() before passing oops
241   // to closures.
242 
243   static const ImmutableOopMap* find_map(const CodeBlob* cb, address pc);
244   static const ImmutableOopMap* find_map(const frame *fr);
245 
246   // Iterates through frame for a compiled method
247   static void oops_do            (const frame* fr,
248                                   const RegisterMap* reg_map,
249                                   OopClosure* f,
250                                   DerivedOopClosure* df);
251   static void oops_do            (const frame* fr,
252                                   const RegisterMap* reg_map,
253                                   OopClosure* f,
254                                   DerivedPointerIterationMode mode);
255   static void update_register_map(const frame* fr, RegisterMap *reg_map);
256 
257 #ifndef PRODUCT
258   static void trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map);
259 #endif
260 
261   // Printing
262   void print_on(outputStream* st) const;
263   void print() const;
264 };
265 
266 class ImmutableOopMapBuilder;
267 
268 class OopMapClosure : public Closure {
269  public:
270   virtual bool handle_type(OopMapValue::oop_types type) { return true; }
271   virtual void do_value(VMReg reg, OopMapValue::oop_types type) = 0;
272 };
273 
274 template <typename OopFnT, typename DerivedOopFnT, typename ValueFilterT>
275 class OopMapDo;
276 
277 class ImmutableOopMap {
278   friend class OopMapStream;
279   friend class VMStructs;
280   template <typename OopFnT, typename DerivedOopFnT, typename ValueFilterT>
281   friend class OopMapDo;
282 #ifdef ASSERT
283   friend class ImmutableOopMapBuilder;
284 #endif
285 private:
286   int _count; // contains the number of entries in this OopMap
287   int _num_oops;
288   bool _has_derived_oops;
289 
290   address data_addr() const { return (address) this + sizeof(ImmutableOopMap); }
291 public:
292   ImmutableOopMap(const OopMap* oopmap);
293 
294   int count() const { return _count; }
295   int num_oops() const { return _num_oops; }
296   bool has_derived_oops() const { return _has_derived_oops; }
297   bool has_any(OopMapValue::oop_types type) const;
298 
299 #ifdef ASSERT
300   int nr_of_bytes() const; // this is an expensive operation, only used in debug builds
301 #endif
302 
303   void oops_do(const frame* fr, const RegisterMap* reg_map, OopClosure* f, DerivedOopClosure* df) const;
304   void oops_do(const frame* fr, const RegisterMap* reg_map, OopClosure* f, DerivedPointerIterationMode derived_mode) const;
305   void all_type_do(const frame *fr, OopMapValue::oop_types type, OopMapClosure* fn) const;
306   void all_type_do(const frame *fr, OopMapClosure* fn) const;
307   void update_register_map(const frame* fr, RegisterMap *reg_map) const;
308 
309   // Printing
310   void print_on(outputStream* st) const;
311   void print() const;
312 };
313 
314 class ImmutableOopMapSet;
315 class ImmutableOopMap;
316 class OopMapSet;
317 
318 class ImmutableOopMapPair {
319   friend class VMStructs;
320 private:
321   int _pc_offset; // program counter offset from the beginning of the method
322   int _oopmap_offset; // offset in the data in the ImmutableOopMapSet where the ImmutableOopMap is located
323 public:
324   ImmutableOopMapPair(int pc_offset, int oopmap_offset) : _pc_offset(pc_offset), _oopmap_offset(oopmap_offset) {
325     assert(pc_offset >= 0 && oopmap_offset >= 0, "check");
326   }
327   const ImmutableOopMap* get_from(const ImmutableOopMapSet* set) const;
328 
329   int pc_offset() const { return _pc_offset; }
330   int oopmap_offset() const { return _oopmap_offset; }
331 };
332 
333 class ImmutableOopMapSet {
334   friend class VMStructs;
335 private:
336   int _count; // nr of ImmutableOopMapPairs in the Set
337   int _size; // nr of bytes including ImmutableOopMapSet itself
338 
339   address data() const { return (address) this + sizeof(*this) + sizeof(ImmutableOopMapPair) * _count; }
340 
341 public:
342   void operator delete(void* p);
343 
344   ImmutableOopMapSet(const OopMapSet* oopmap_set, int size) : _count(oopmap_set->size()), _size(size) {}
345   ~ImmutableOopMapSet() = default;
346 
347   ImmutableOopMap* oopmap_at_offset(int offset) const {
348     assert(offset >= 0 && offset < _size, "must be within boundaries");
349     address addr = data() + offset;
350     return (ImmutableOopMap*) addr;
351   }
352 
353   ImmutableOopMapPair* get_pairs() const { return (ImmutableOopMapPair*) ((address) this + sizeof(*this)); }
354 
355   static ImmutableOopMapSet* build_from(const OopMapSet* oopmap_set);
356 
357   int find_slot_for_offset(int pc_offset) const;
358   const ImmutableOopMap* find_map_at_offset(int pc_offset) const;
359   const ImmutableOopMap* find_map_at_slot(int slot, int pc_offset) const;
360 
361   const ImmutableOopMapPair* pair_at(int index) const { assert(index >= 0 && index < _count, "check"); return &get_pairs()[index]; }
362 
363   int count() const { return _count; }
364   int nr_of_bytes() const { return _size; }
365 
366   void print_on(outputStream* st) const;
367   void print() const;
368 };
369 
370 class OopMapStream : public StackObj {
371  private:
372   CompressedReadStream _stream;
373   int _size;
374   int _position;
375   bool _valid_omv;
376   OopMapValue _omv;
377   void find_next();
378 
379  public:
380   OopMapStream(const OopMap* oop_map);
381   OopMapStream(const ImmutableOopMap* oop_map);
382   bool is_done()                        { if(!_valid_omv) { find_next(); } return !_valid_omv; }
383   void next()                           { find_next(); }
384   OopMapValue current()                 { return _omv; }
385 #ifdef ASSERT
386   int stream_position() const           { return _stream.position(); }
387 #endif
388 };
389 
390 class ImmutableOopMapBuilder {
391 private:
392   class Mapping;
393 
394 private:
395   const OopMapSet* _set;
396   const OopMap* _empty;
397   const OopMap* _last;
398   int _empty_offset;
399   int _last_offset;
400   int _offset;
401   int _required;
402   Mapping* _mapping;
403   ImmutableOopMapSet* _new_set;
404 
405   /* Used for bookkeeping when building ImmutableOopMaps */
406   class Mapping : public ResourceObj {
407   public:
408     enum kind_t { OOPMAP_UNKNOWN = 0, OOPMAP_NEW = 1, OOPMAP_EMPTY = 2, OOPMAP_DUPLICATE = 3 };
409 
410     kind_t _kind;
411     int _offset;
412     int _size;
413     const OopMap* _map;
414     const OopMap* _other;
415 
416     Mapping() : _kind(OOPMAP_UNKNOWN), _offset(-1), _size(-1), _map(nullptr) {}
417 
418     void set(kind_t kind, int offset, int size, const OopMap* map, const OopMap* other = nullptr) {
419       _kind = kind;
420       _offset = offset;
421       _size = size;
422       _map = map;
423       _other = other;
424     }
425   };
426 
427 public:
428   ImmutableOopMapBuilder(const OopMapSet* set);
429 
430   int heap_size();
431   ImmutableOopMapSet* build();
432   ImmutableOopMapSet* generate_into(address buffer);
433 private:
434   bool is_empty(const OopMap* map) const {
435     return map->count() == 0;
436   }
437 
438   bool is_last_duplicate(const OopMap* map) {
439     if (_last != nullptr && _last->count() > 0 && _last->equals(map)) {
440       return true;
441     }
442     return false;
443   }
444 
445 #ifdef ASSERT
446   void verify(address buffer, int size, const ImmutableOopMapSet* set);
447 #endif
448 
449   bool has_empty() const {
450     return _empty_offset != -1;
451   }
452 
453   int size_for(const OopMap* map) const;
454   void fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);
455   int fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set);
456   void fill(ImmutableOopMapSet* set, int size);
457 };
458 
459 class SkipNullValue {
460 public:
461   static inline bool should_skip(void* val);
462 };
463 
464 class IncludeAllValues {
465 public:
466   static bool should_skip(void* value) { return false; }
467 };
468 
469 template <typename OopFnT, typename DerivedOopFnT, typename ValueFilterT>
470 class OopMapDo {
471 private:
472   OopFnT* _oop_fn;
473   DerivedOopFnT* _derived_oop_fn;
474 public:
475   OopMapDo(OopFnT* oop_fn, DerivedOopFnT* derived_oop_fn) : _oop_fn(oop_fn), _derived_oop_fn(derived_oop_fn) {}
476   template <typename RegisterMapT>
477   void oops_do(const frame* fr, const RegisterMapT* reg_map, const ImmutableOopMap* oopmap);
478 private:
479   template <typename RegisterMapT>
480   void iterate_oops_do(const frame *fr, const RegisterMapT *reg_map, const ImmutableOopMap* oopmap);
481 };
482 
483 // Derived pointer support. This table keeps track of all derived points on a
484 // stack.  It is cleared before each scavenge/GC.  During the traversal of all
485 // oops, it is filled in with references to all locations that contains a
486 // derived oop (assumed to be very few).  When the GC is complete, the derived
487 // pointers are updated based on their base pointers new value and an offset.
488 #if COMPILER2_OR_JVMCI
489 class DerivedPointerTable : public AllStatic {
490   friend class VMStructs;
491  private:
492   class Entry;
493   static bool _active;                                           // do not record pointers for verify pass etc.
494 
495  public:
496   static void clear();                                           // Called before scavenge/GC
497   static void add(derived_pointer* derived, derived_base* base); // Called during scavenge/GC
498   static void update_pointers();                                 // Called after  scavenge/GC
499   static bool is_empty();
500   static bool is_active()                    { return _active; }
501   static void set_active(bool value)         { _active = value; }
502 };
503 
504 // A utility class to temporarily "deactivate" the DerivedPointerTable.
505 // (Note: clients are responsible for any MT-safety issues)
506 class DerivedPointerTableDeactivate: public StackObj {
507  private:
508   bool _active;
509  public:
510   DerivedPointerTableDeactivate() {
511     _active = DerivedPointerTable::is_active();
512     if (_active) {
513       DerivedPointerTable::set_active(false);
514     }
515   }
516 
517   ~DerivedPointerTableDeactivate() {
518     assert(!DerivedPointerTable::is_active(),
519            "Inconsistency: not MT-safe");
520     if (_active) {
521       DerivedPointerTable::set_active(true);
522     }
523   }
524 };
525 #endif // COMPILER2_OR_JVMCI
526 
527 #endif // SHARE_COMPILER_OOPMAP_HPP