1 /*
2 * Copyright (c) 1997, 2023, 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_OOPS_GENERATEOOPMAP_HPP
26 #define SHARE_OOPS_GENERATEOOPMAP_HPP
27
28 #include "memory/allocation.hpp"
29 #include "oops/method.hpp"
30 #include "oops/oopsHierarchy.hpp"
31 #include "runtime/signature.hpp"
32 #include "utilities/bitMap.hpp"
33
34 // Forward definition
35 class BytecodeStream;
36 class GenerateOopMap;
37 class BasicBlock;
38 class CellTypeState;
39 class StackMap;
40
41 // These two should be removed. But requires some code to be cleaned up
42 #define MAXARGSIZE 256 // This should be enough
43 #define MAX_LOCAL_VARS 65536 // 16-bit entry
44
45 typedef void (*jmpFct_t)(GenerateOopMap *c, int bcpDelta, int* data);
46
47
48 // RetTable
49 //
50 // Contains mapping between jsr targets and there return addresses. One-to-many mapping
51 //
52 class RetTableEntry : public ResourceObj {
53 private:
54 static int _init_nof_jsrs; // Default size of jsrs list
55 int _target_bci; // Target PC address of jump (bytecode index)
56 GrowableArray<int> * _jsrs; // List of return addresses (bytecode index)
57 RetTableEntry *_next; // Link to next entry
58 public:
59 RetTableEntry(int target, RetTableEntry *next);
60
61 // Query
62 int target_bci() const { return _target_bci; }
63 int nof_jsrs() const { return _jsrs->length(); }
64 int jsrs(int i) const { assert(i>=0 && i<nof_jsrs(), "Index out of bounds"); return _jsrs->at(i); }
65
66 // Update entry
67 void add_jsr (int return_bci) { _jsrs->append(return_bci); }
68 void add_delta (int bci, int delta);
69 RetTableEntry * next() const { return _next; }
70 };
71
72
73 class RetTable {
74 private:
75 RetTableEntry *_first;
76 static int _init_nof_entries;
77
78 void add_jsr(int return_bci, int target_bci); // Adds entry to list
79 public:
80 RetTable() { _first = nullptr; }
81 void compute_ret_table(const methodHandle& method);
82 void update_ret_table(int bci, int delta);
83 RetTableEntry* find_jsrs_for_target(int targBci);
84 };
85
86 //
87 // CellTypeState
88 //
89 class CellTypeState {
90 private:
91 unsigned int _state;
92
93 // Masks for separating the BITS and INFO portions of a CellTypeState
94 enum { info_mask = right_n_bits(28),
95 bits_mask = (int)(~info_mask) };
96
97 // These constant are used for manipulating the BITS portion of a
98 // CellTypeState
99 enum { uninit_bit = (int)(nth_bit(31)),
100 ref_bit = nth_bit(30),
101 val_bit = nth_bit(29),
102 addr_bit = nth_bit(28),
103 live_bits_mask = (int)(bits_mask & ~uninit_bit) };
104
105 // These constants are used for manipulating the INFO portion of a
106 // CellTypeState
107 enum { top_info_bit = nth_bit(27),
108 not_bottom_info_bit = nth_bit(26),
109 info_data_mask = right_n_bits(26),
110 info_conflict = info_mask };
111
112 // Within the INFO data, these values are used to distinguish different
113 // kinds of references.
114 enum { ref_not_lock_bit = nth_bit(25), // 0 if this reference is locked as a monitor
115 ref_slot_bit = nth_bit(24), // 1 if this reference is a "slot" reference,
116 // 0 if it is a "line" reference.
117 ref_data_mask = right_n_bits(24) };
118
119
120 // These values are used to initialize commonly used CellTypeState
121 // constants.
122 enum { bottom_value = 0,
123 uninit_value = (int)(uninit_bit | info_conflict),
124 ref_value = ref_bit,
125 ref_conflict = ref_bit | info_conflict,
126 val_value = val_bit | info_conflict,
127 addr_value = addr_bit,
128 addr_conflict = addr_bit | info_conflict };
129
130 public:
131
132 // Since some C++ constructors generate poor code for declarations of the
133 // form...
134 //
135 // CellTypeState vector[length];
136 //
137 // ...we avoid making a constructor for this class. CellTypeState values
138 // should be constructed using one of the make_* methods:
139
140 static CellTypeState make_any(int state) {
141 CellTypeState s;
142 s._state = state;
143 // Causes SS10 warning.
144 // assert(s.is_valid_state(), "check to see if CellTypeState is valid");
145 return s;
146 }
147
148 static CellTypeState make_bottom() {
149 return make_any(0);
150 }
151
152 static CellTypeState make_top() {
153 return make_any(AllBits);
154 }
155
156 static CellTypeState make_addr(int bci) {
157 assert((bci >= 0) && (bci < info_data_mask), "check to see if ret addr is valid");
158 return make_any(addr_bit | not_bottom_info_bit | (bci & info_data_mask));
159 }
160
161 static CellTypeState make_slot_ref(int slot_num) {
162 assert(slot_num >= 0 && slot_num < ref_data_mask, "slot out of range");
163 return make_any(ref_bit | not_bottom_info_bit | ref_not_lock_bit | ref_slot_bit |
164 (slot_num & ref_data_mask));
165 }
166
167 static CellTypeState make_line_ref(int bci) {
168 assert(bci >= 0 && bci < ref_data_mask, "line out of range");
169 return make_any(ref_bit | not_bottom_info_bit | ref_not_lock_bit |
170 (bci & ref_data_mask));
171 }
172
173 static CellTypeState make_lock_ref(int bci) {
174 assert(bci >= 0 && bci < ref_data_mask, "line out of range");
175 return make_any(ref_bit | not_bottom_info_bit | (bci & ref_data_mask));
176 }
177
178 // Query methods:
179 bool is_bottom() const { return _state == 0; }
180 bool is_live() const { return ((_state & live_bits_mask) != 0); }
181 bool is_valid_state() const {
182 // Uninitialized and value cells must contain no data in their info field:
183 if ((can_be_uninit() || can_be_value()) && !is_info_top()) {
184 return false;
185 }
186 // The top bit is only set when all info bits are set:
187 if (is_info_top() && ((_state & info_mask) != info_mask)) {
188 return false;
189 }
190 // The not_bottom_bit must be set when any other info bit is set:
191 if (is_info_bottom() && ((_state & info_mask) != 0)) {
192 return false;
193 }
194 return true;
195 }
196
197 bool is_address() const { return ((_state & bits_mask) == addr_bit); }
198 bool is_reference() const { return ((_state & bits_mask) == ref_bit); }
199 bool is_value() const { return ((_state & bits_mask) == val_bit); }
200 bool is_uninit() const { return ((_state & bits_mask) == (uint)uninit_bit); }
201
202 bool can_be_address() const { return ((_state & addr_bit) != 0); }
203 bool can_be_reference() const { return ((_state & ref_bit) != 0); }
204 bool can_be_value() const { return ((_state & val_bit) != 0); }
205 bool can_be_uninit() const { return ((_state & uninit_bit) != 0); }
206
207 bool is_info_bottom() const { return ((_state & not_bottom_info_bit) == 0); }
208 bool is_info_top() const { return ((_state & top_info_bit) != 0); }
209 int get_info() const {
210 assert((!is_info_top() && !is_info_bottom()),
211 "check to make sure top/bottom info is not used");
212 return (_state & info_data_mask);
213 }
214
215 bool is_good_address() const { return is_address() && !is_info_top(); }
216 bool is_lock_reference() const {
217 return ((_state & (bits_mask | top_info_bit | ref_not_lock_bit)) == ref_bit);
218 }
219 bool is_nonlock_reference() const {
220 return ((_state & (bits_mask | top_info_bit | ref_not_lock_bit)) == (ref_bit | ref_not_lock_bit));
221 }
222
223 bool equal(CellTypeState a) const { return _state == a._state; }
224 bool equal_kind(CellTypeState a) const {
225 return (_state & bits_mask) == (a._state & bits_mask);
226 }
227
228 char to_char() const;
229
230 // Merge
231 CellTypeState merge (CellTypeState cts, int slot) const;
232
233 // Debugging output
234 void print(outputStream *os);
235
236 // Default values of common values
237 static CellTypeState bottom;
238 static CellTypeState uninit;
239 static CellTypeState ref;
240 static CellTypeState value;
241 static CellTypeState refUninit;
242 static CellTypeState varUninit;
243 static CellTypeState top;
244 static CellTypeState addr;
245 };
246
247
248 //
249 // BasicBlockStruct
250 //
251 class BasicBlock: ResourceObj {
252 private:
253 bool _changed; // Reached a fixpoint or not
254 public:
255 enum Constants {
256 _dead_basic_block = -2,
257 _unreached = -1 // Alive but not yet reached by analysis
258 // >=0 // Alive and has a merged state
259 };
260
261 int _bci; // Start of basic block
262 int _end_bci; // Bci of last instruction in basicblock
263 int _max_locals; // Determines split between vars and stack
264 int _max_stack; // Determines split between stack and monitors
265 CellTypeState* _state; // State (vars, stack) at entry.
266 int _stack_top; // -1 indicates bottom stack value.
267 int _monitor_top; // -1 indicates bottom monitor stack value.
268
269 CellTypeState* vars() { return _state; }
270 CellTypeState* stack() { return _state + _max_locals; }
271
272 bool changed() { return _changed; }
273 void set_changed(bool s) { _changed = s; }
274
275 bool is_reachable() const { return _stack_top >= 0; } // Analysis has reached this basicblock
276
277 // All basicblocks that are unreachable are going to have a _stack_top == _dead_basic_block.
278 // This info. is setup in a pre-parse before the real abstract interpretation starts.
279 bool is_dead() const { return _stack_top == _dead_basic_block; }
280 bool is_alive() const { return _stack_top != _dead_basic_block; }
281 void mark_as_alive() { assert(is_dead(), "must be dead"); _stack_top = _unreached; }
282 };
283
284
285 //
286 // GenerateOopMap
287 //
288 // Main class used to compute the pointer-maps in a Method
289 //
290 class GenerateOopMap {
291 protected:
292
293 // _monitor_top is set to this constant to indicate that a monitor matching
294 // problem was encountered prior to this point in control flow.
295 enum { bad_monitors = -1 };
296
297 // Main variables
298 methodHandle _method; // The method we are examine
299 RetTable _rt; // Contains the return address mappings
300 int _max_locals; // Cached value of no. of locals
301 int _max_stack; // Cached value of max. stack depth
302 int _max_monitors; // Cached value of max. monitor stack depth
303 int _has_exceptions; // True, if exceptions exist for method
304 bool _got_error; // True, if an error occurred during interpretation.
305 Handle _exception; // Exception if got_error is true.
306 bool _did_rewriting; // was bytecodes rewritten
307 bool _did_relocation; // was relocation necessary
308 bool _monitor_safe; // The monitors in this method have been determined
309 // to be safe.
310
311 // Working Cell type state
312 int _state_len; // Size of states
313 CellTypeState *_state; // list of states
314 char *_state_vec_buf; // Buffer used to print a readable version of a state
315 int _stack_top;
316 int _monitor_top;
317
318 // Timing and statistics
319 static elapsedTimer _total_oopmap_time; // Holds cumulative oopmap generation time
320 static uint64_t _total_byte_count; // Holds cumulative number of bytes inspected
321
322 // Cell type methods
323 void init_state();
324 void make_context_uninitialized ();
325 int methodsig_to_effect (Symbol* signature, bool isStatic, CellTypeState* effect);
326 bool merge_local_state_vectors (CellTypeState* cts, CellTypeState* bbts);
327 bool merge_monitor_state_vectors(CellTypeState* cts, CellTypeState* bbts);
328 void copy_state (CellTypeState *dst, CellTypeState *src);
329 void merge_state_into_bb (BasicBlock *bb);
330 static void merge_state (GenerateOopMap *gom, int bcidelta, int* data);
331 void set_var (int localNo, CellTypeState cts);
332 CellTypeState get_var (int localNo);
333 CellTypeState pop ();
334 void push (CellTypeState cts);
335 CellTypeState monitor_pop ();
336 void monitor_push (CellTypeState cts);
337 CellTypeState * vars () { return _state; }
338 CellTypeState * stack () { return _state+_max_locals; }
339 CellTypeState * monitors () { return _state+_max_locals+_max_stack; }
340
341 void replace_all_CTS_matches (CellTypeState match,
342 CellTypeState replace);
343 void print_states (outputStream *os, CellTypeState *vector, int num);
344 void print_current_state (outputStream *os,
345 BytecodeStream *itr,
346 bool detailed);
347 void report_monitor_mismatch (const char *msg);
348
349 // Basicblock info
350 BasicBlock * _basic_blocks; // Array of basicblock info
351 int _gc_points;
352 int _bb_count;
353 ResourceBitMap _bb_hdr_bits;
354
355 // Basicblocks methods
356 void initialize_bb ();
357 void mark_bbheaders_and_count_gc_points();
358 bool is_bb_header (int bci) const {
359 return _bb_hdr_bits.at(bci);
360 }
361 int gc_points () const { return _gc_points; }
362 int bb_count () const { return _bb_count; }
363 void set_bbmark_bit (int bci);
364 BasicBlock * get_basic_block_at (int bci) const;
365 BasicBlock * get_basic_block_containing (int bci) const;
366 void interp_bb (BasicBlock *bb);
367 void restore_state (BasicBlock *bb);
368 int next_bb_start_pc (BasicBlock *bb);
369 void update_basic_blocks (int bci, int delta, int new_method_size);
370 static void bb_mark_fct (GenerateOopMap *c, int deltaBci, int *data);
371
372 // Dead code detection
373 void mark_reachable_code();
374 static void reachable_basicblock (GenerateOopMap *c, int deltaBci, int *data);
375
376 // Interpretation methods (primary)
377 void do_interpretation ();
378 void init_basic_blocks ();
379 void setup_method_entry_state ();
380 void interp_all ();
381
382 // Interpretation methods (secondary)
383 void interp1 (BytecodeStream *itr);
384 void do_exception_edge (BytecodeStream *itr);
385 void check_type (CellTypeState expected, CellTypeState actual);
386 void ppstore (CellTypeState *in, int loc_no);
387 void ppload (CellTypeState *out, int loc_no);
388 void ppush1 (CellTypeState in);
389 void ppush (CellTypeState *in);
390 void ppop1 (CellTypeState out);
391 void ppop (CellTypeState *out);
392 void ppop_any (int poplen);
393 void pp (CellTypeState *in, CellTypeState *out);
394 void pp_new_ref (CellTypeState *in, int bci);
395 void ppdupswap (int poplen, const char *out);
396 void do_ldc (int bci);
397 void do_astore (int idx);
398 void do_jsr (int delta);
399 void do_field (int is_get, int is_static, int idx, int bci, Bytecodes::Code bc);
400 void do_method (int is_static, int is_interface, int idx, int bci, Bytecodes::Code bc);
401 void do_multianewarray (int dims, int bci);
402 void do_monitorenter (int bci);
403 void do_monitorexit (int bci);
404 void do_return_monitor_check ();
405 void do_checkcast ();
406 CellTypeState *signature_to_effect (const Symbol* sig, int bci, CellTypeState *out);
407 int copy_cts (CellTypeState *dst, CellTypeState *src);
408
409 // Error handling
410 void error_work (const char *format, va_list ap) ATTRIBUTE_PRINTF(2, 0);
411 void report_error (const char *format, ...) ATTRIBUTE_PRINTF(2, 3);
412 void verify_error (const char *format, ...) ATTRIBUTE_PRINTF(2, 3);
413 bool got_error() { return _got_error; }
414
415 // Create result set
416 bool _report_result;
417 bool _report_result_for_send; // Unfortunately, stackmaps for sends are special, so we need some extra
418 BytecodeStream *_itr_send; // variables to handle them properly.
419
420 void report_result ();
421
422 // Initvars
423 GrowableArray<intptr_t> * _init_vars;
424
425 void initialize_vars ();
426 void add_to_ref_init_set (int localNo);
427
428 // Conflicts rewrite logic
429 bool _conflict; // True, if a conflict occurred during interpretation
430 int _nof_refval_conflicts; // No. of conflicts that require rewrites
431 int * _new_var_map;
432
433 void record_refval_conflict (int varNo);
434 void rewrite_refval_conflicts ();
435 void rewrite_refval_conflict (int from, int to);
436 bool rewrite_refval_conflict_inst (BytecodeStream *i, int from, int to);
437 bool rewrite_load_or_store (BytecodeStream *i, Bytecodes::Code bc, Bytecodes::Code bc0, unsigned int varNo);
438
439 void expand_current_instr (int bci, int ilen, int newIlen, u_char inst_buffer[]);
440 bool is_astore (BytecodeStream *itr, int *index);
441 bool is_aload (BytecodeStream *itr, int *index);
442
443 // List of bci's where a return address is on top of the stack
444 GrowableArray<int>* _ret_adr_tos;
445
446 bool stack_top_holds_ret_addr (int bci);
447 void compute_ret_adr_at_TOS ();
448 void update_ret_adr_at_TOS (int bci, int delta);
449
450 int binsToHold (int no) { return ((no+(BitsPerWord-1))/BitsPerWord); }
451 char *state_vec_to_string (CellTypeState* vec, int len);
452
453 // Helper method. Can be used in subclasses to fx. calculate gc_points. If the current instruction
454 // is a control transfer, then calls the jmpFct all possible destinations.
455 void ret_jump_targets_do (BytecodeStream *bcs, jmpFct_t jmpFct, int varNo,int *data);
456 bool jump_targets_do (BytecodeStream *bcs, jmpFct_t jmpFct, int *data);
457
458 friend class RelocCallback;
459 public:
460 GenerateOopMap(const methodHandle& method);
461
462 // Compute the map - returns true on success and false on error.
463 bool compute_map(Thread* current);
464 // Returns the exception related to any error, if the map was computed by a suitable JavaThread.
465 Handle exception() { return _exception; }
466
467 void result_for_basicblock(int bci); // Do a callback on fill_stackmap_for_opcodes for basicblock containing bci
468
469 // Query
470 int max_locals() const { return _max_locals; }
471 Method* method() const { return _method(); }
472 methodHandle method_as_handle() const { return _method; }
473
474 bool did_rewriting() { return _did_rewriting; }
475 bool did_relocation() { return _did_relocation; }
476
477 static void print_time();
478
479 // Monitor query
480 bool monitor_safe() { return _monitor_safe; }
481
482 // Specialization methods. Intended use:
483 // - possible_gc_point must return true for every bci for which the stackmaps must be returned
484 // - fill_stackmap_prolog is called just before the result is reported. The arguments tells the estimated
485 // number of gc points
486 // - fill_stackmap_for_opcodes is called once for each bytecode index in order (0...code_length-1)
487 // - fill_stackmap_epilog is called after all results has been reported. Note: Since the algorithm does not report
488 // stackmaps for deadcode, fewer gc_points might have been encountered than assumed during the epilog. It is the
489 // responsibility of the subclass to count the correct number.
490 // - fill_init_vars are called once with the result of the init_vars computation
491 //
492 // All these methods are used during a call to: compute_map. Note: Non of the return results are valid
493 // after compute_map returns, since all values are allocated as resource objects.
494 //
495 // All virtual method must be implemented in subclasses
496 virtual bool allow_rewrites () const { return false; }
497 virtual bool report_results () const { return true; }
498 virtual bool report_init_vars () const { return true; }
499 virtual bool possible_gc_point (BytecodeStream *bcs) { ShouldNotReachHere(); return false; }
500 virtual void fill_stackmap_prolog (int nof_gc_points) { ShouldNotReachHere(); }
501 virtual void fill_stackmap_epilog () { ShouldNotReachHere(); }
502 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
503 CellTypeState* vars,
504 CellTypeState* stack,
505 int stackTop) { ShouldNotReachHere(); }
506 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars) { ShouldNotReachHere();; }
507 };
508
509 //
510 // Subclass of the GenerateOopMap Class that just do rewrites of the method, if needed.
511 // It does not store any oopmaps.
512 //
513 class ResolveOopMapConflicts: public GenerateOopMap {
514 private:
515
516 bool _must_clear_locals;
517
518 virtual bool report_results() const { return false; }
519 virtual bool report_init_vars() const { return true; }
520 virtual bool allow_rewrites() const { return true; }
521 virtual bool possible_gc_point (BytecodeStream *bcs) { return false; }
522 virtual void fill_stackmap_prolog (int nof_gc_points) {}
523 virtual void fill_stackmap_epilog () {}
524 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
525 CellTypeState* vars,
526 CellTypeState* stack,
527 int stack_top) {}
528 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars) { _must_clear_locals = init_vars->length() > 0; }
529
530 #ifndef PRODUCT
531 // Statistics
532 static int _nof_invocations;
533 static int _nof_rewrites;
534 static int _nof_relocations;
535 #endif
536
537 public:
538 ResolveOopMapConflicts(const methodHandle& method) : GenerateOopMap(method) { _must_clear_locals = false; };
539
540 methodHandle do_potential_rewrite(TRAPS);
541 bool must_clear_locals() const { return _must_clear_locals; }
542 };
543
544
545 //
546 // Subclass used by the compiler to generate pairing information
547 //
548 class GeneratePairingInfo: public GenerateOopMap {
549 private:
550
551 virtual bool report_results() const { return false; }
552 virtual bool report_init_vars() const { return false; }
553 virtual bool allow_rewrites() const { return false; }
554 virtual bool possible_gc_point (BytecodeStream *bcs) { return false; }
555 virtual void fill_stackmap_prolog (int nof_gc_points) {}
556 virtual void fill_stackmap_epilog () {}
557 virtual void fill_stackmap_for_opcodes (BytecodeStream *bcs,
558 CellTypeState* vars,
559 CellTypeState* stack,
560 int stack_top) {}
561 virtual void fill_init_vars (GrowableArray<intptr_t> *init_vars) {}
562 public:
563 GeneratePairingInfo(const methodHandle& method) : GenerateOopMap(method) {};
564
565 // Call compute_map() to generate info.
566 };
567
568 #endif // SHARE_OOPS_GENERATEOOPMAP_HPP