1 /*
2 * Copyright (c) 1997, 2019, 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.
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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
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23 */
24
25 #ifndef SHARE_CODE_NMETHOD_HPP
26 #define SHARE_CODE_NMETHOD_HPP
27
28 #include "code/compiledMethod.hpp"
29 #include "compiler/compilerDefinitions.hpp"
30
31 class DepChange;
32 class DirectiveSet;
33 class DebugInformationRecorder;
34
35 // nmethods (native methods) are the compiled code versions of Java methods.
36 //
37 // An nmethod contains:
38 // - header (the nmethod structure)
39 // [Relocation]
40 // - relocation information
41 // - constant part (doubles, longs and floats used in nmethod)
42 // - oop table
43 // [Code]
44 // - code body
45 // - exception handler
46 // - stub code
47 // [Debugging information]
48 // - oop array
49 // - data array
50 // - pcs
51 // [Exception handler table]
52 // - handler entry point array
53 // [Implicit Null Pointer exception table]
54 // - implicit null table array
55
56 class nmethod : public CompiledMethod {
57 friend class VMStructs;
58 friend class JVMCIVMStructs;
59 friend class NMethodSweeper;
60 friend class CodeCache; // scavengable oops
61 private:
62
63 // Shared fields for all nmethod's
64 int _entry_bci; // != InvocationEntryBci if this nmethod is an on-stack replacement method
65 jmethodID _jmethod_id; // Cache of method()->jmethod_id()
66
67 #if INCLUDE_JVMCI
68 // A weak reference to an InstalledCode object associated with
69 // this nmethod.
70 jweak _jvmci_installed_code;
71
72 // A weak reference to a SpeculationLog object associated with
73 // this nmethod.
74 jweak _speculation_log;
75
76 // Determines whether this nmethod is unloaded when the
77 // referent in _jvmci_installed_code is cleared. This
78 // will be false if the referent is initialized to a
79 // HotSpotNMethod object whose isDefault field is true.
80 // That is, installed code other than a "default"
81 // HotSpotNMethod causes nmethod unloading.
82 // This field is ignored once _jvmci_installed_code is NULL.
83 bool _jvmci_installed_code_triggers_invalidation;
84 #endif
85
86 // To support simple linked-list chaining of nmethods:
87 nmethod* _osr_link; // from InstanceKlass::osr_nmethods_head
88
89 static nmethod* volatile _oops_do_mark_nmethods;
90 nmethod* volatile _oops_do_mark_link;
91
92 // offsets for entry points
93 address _entry_point; // entry point with class check
94 address _verified_entry_point; // entry point without class check
95 address _verified_value_entry_point; // value type entry point (unpack all value args) without class check
96 address _verified_value_ro_entry_point; // value type entry point (unpack receiver only) without class check
97 address _osr_entry_point; // entry point for on stack replacement
98
99 // Offsets for different nmethod parts
100 int _exception_offset;
101 // Offset of the unwind handler if it exists
102 int _unwind_handler_offset;
103
104 int _consts_offset;
105 int _stub_offset;
106 int _oops_offset; // offset to where embedded oop table begins (inside data)
107 int _metadata_offset; // embedded meta data table
108 int _scopes_data_offset;
109 int _scopes_pcs_offset;
110 int _dependencies_offset;
111 int _handler_table_offset;
112 int _nul_chk_table_offset;
113 int _nmethod_end_offset;
114
115 int code_offset() const { return (address) code_begin() - header_begin(); }
116
117 // location in frame (offset for sp) that deopt can store the original
118 // pc during a deopt.
119 int _orig_pc_offset;
120
121 int _compile_id; // which compilation made this nmethod
122 int _comp_level; // compilation level
123
124 // protected by CodeCache_lock
125 bool _has_flushed_dependencies; // Used for maintenance of dependencies (CodeCache_lock)
126
127 // used by jvmti to track if an unload event has been posted for this nmethod.
128 bool _unload_reported;
129
130 // Protected by Patching_lock
131 volatile signed char _state; // {not_installed, in_use, not_entrant, zombie, unloaded}
132
133 #ifdef ASSERT
134 bool _oops_are_stale; // indicates that it's no longer safe to access oops section
135 #endif
136
137 #if INCLUDE_RTM_OPT
138 // RTM state at compile time. Used during deoptimization to decide
139 // whether to restart collecting RTM locking abort statistic again.
140 RTMState _rtm_state;
141 #endif
142
143 // Nmethod Flushing lock. If non-zero, then the nmethod is not removed
144 // and is not made into a zombie. However, once the nmethod is made into
145 // a zombie, it will be locked one final time if CompiledMethodUnload
146 // event processing needs to be done.
147 volatile jint _lock_count;
148
149 // not_entrant method removal. Each mark_sweep pass will update
150 // this mark to current sweep invocation count if it is seen on the
151 // stack. An not_entrant method can be removed when there are no
152 // more activations, i.e., when the _stack_traversal_mark is less than
153 // current sweep traversal index.
154 volatile long _stack_traversal_mark;
155
156 // The _hotness_counter indicates the hotness of a method. The higher
157 // the value the hotter the method. The hotness counter of a nmethod is
158 // set to [(ReservedCodeCacheSize / (1024 * 1024)) * 2] each time the method
159 // is active while stack scanning (mark_active_nmethods()). The hotness
160 // counter is decreased (by 1) while sweeping.
161 int _hotness_counter;
162
163 // Local state used to keep track of whether unloading is happening or not
164 volatile uint8_t _is_unloading_state;
165
166 // These are used for compiled synchronized native methods to
167 // locate the owner and stack slot for the BasicLock so that we can
168 // properly revoke the bias of the owner if necessary. They are
169 // needed because there is no debug information for compiled native
170 // wrappers and the oop maps are insufficient to allow
171 // frame::retrieve_receiver() to work. Currently they are expected
172 // to be byte offsets from the Java stack pointer for maximum code
173 // sharing between platforms. Note that currently biased locking
174 // will never cause Class instances to be biased but this code
175 // handles the static synchronized case as well.
176 // JVMTI's GetLocalInstance() also uses these offsets to find the receiver
177 // for non-static native wrapper frames.
178 ByteSize _native_receiver_sp_offset;
179 ByteSize _native_basic_lock_sp_offset;
180
181 friend class nmethodLocker;
182
183 // For native wrappers
184 nmethod(Method* method,
185 CompilerType type,
186 int nmethod_size,
187 int compile_id,
188 CodeOffsets* offsets,
189 CodeBuffer *code_buffer,
190 int frame_size,
191 ByteSize basic_lock_owner_sp_offset, /* synchronized natives only */
192 ByteSize basic_lock_sp_offset, /* synchronized natives only */
193 OopMapSet* oop_maps);
194
195 // Creation support
196 nmethod(Method* method,
197 CompilerType type,
198 int nmethod_size,
199 int compile_id,
200 int entry_bci,
201 CodeOffsets* offsets,
202 int orig_pc_offset,
203 DebugInformationRecorder *recorder,
204 Dependencies* dependencies,
205 CodeBuffer *code_buffer,
206 int frame_size,
207 OopMapSet* oop_maps,
208 ExceptionHandlerTable* handler_table,
209 ImplicitExceptionTable* nul_chk_table,
210 AbstractCompiler* compiler,
211 int comp_level
212 #if INCLUDE_JVMCI
213 , jweak installed_code,
214 jweak speculation_log
215 #endif
216 );
217
218 // helper methods
219 void* operator new(size_t size, int nmethod_size, int comp_level) throw();
220
221 const char* reloc_string_for(u_char* begin, u_char* end);
222 // Returns true if this thread changed the state of the nmethod or
223 // false if another thread performed the transition.
224 bool make_not_entrant_or_zombie(int state);
225 bool make_entrant() { Unimplemented(); return false; }
226 void inc_decompile_count();
227
228 // Inform external interfaces that a compiled method has been unloaded
229 void post_compiled_method_unload();
230
231 // Initailize fields to their default values
232 void init_defaults();
233
234 // Offsets
235 int content_offset() const { return content_begin() - header_begin(); }
236 int data_offset() const { return _data_offset; }
237
238 address header_end() const { return (address) header_begin() + header_size(); }
239
240 public:
241 // create nmethod with entry_bci
242 static nmethod* new_nmethod(const methodHandle& method,
243 int compile_id,
244 int entry_bci,
245 CodeOffsets* offsets,
246 int orig_pc_offset,
247 DebugInformationRecorder* recorder,
248 Dependencies* dependencies,
249 CodeBuffer *code_buffer,
250 int frame_size,
251 OopMapSet* oop_maps,
252 ExceptionHandlerTable* handler_table,
253 ImplicitExceptionTable* nul_chk_table,
254 AbstractCompiler* compiler,
255 int comp_level
256 #if INCLUDE_JVMCI
257 , jweak installed_code = NULL,
258 jweak speculation_log = NULL
259 #endif
260 );
261
262 // Only used for unit tests.
263 nmethod()
264 : CompiledMethod(),
265 _is_unloading_state(0),
266 _native_receiver_sp_offset(in_ByteSize(-1)),
267 _native_basic_lock_sp_offset(in_ByteSize(-1)) {}
268
269
270 static nmethod* new_native_nmethod(const methodHandle& method,
271 int compile_id,
272 CodeBuffer *code_buffer,
273 int vep_offset,
274 int frame_complete,
275 int frame_size,
276 ByteSize receiver_sp_offset,
277 ByteSize basic_lock_sp_offset,
278 OopMapSet* oop_maps);
279
280 // type info
281 bool is_nmethod() const { return true; }
282 bool is_osr_method() const { return _entry_bci != InvocationEntryBci; }
283
284 // boundaries for different parts
285 address consts_begin () const { return header_begin() + _consts_offset ; }
286 address consts_end () const { return code_begin() ; }
287 address stub_begin () const { return header_begin() + _stub_offset ; }
288 address stub_end () const { return header_begin() + _oops_offset ; }
289 address exception_begin () const { return header_begin() + _exception_offset ; }
290 address unwind_handler_begin () const { return _unwind_handler_offset != -1 ? (header_begin() + _unwind_handler_offset) : NULL; }
291 oop* oops_begin () const { return (oop*) (header_begin() + _oops_offset) ; }
292 oop* oops_end () const { return (oop*) (header_begin() + _metadata_offset) ; }
293
294 Metadata** metadata_begin () const { return (Metadata**) (header_begin() + _metadata_offset) ; }
295 Metadata** metadata_end () const { return (Metadata**) _scopes_data_begin; }
296
297 address scopes_data_end () const { return header_begin() + _scopes_pcs_offset ; }
298 PcDesc* scopes_pcs_begin () const { return (PcDesc*)(header_begin() + _scopes_pcs_offset ); }
299 PcDesc* scopes_pcs_end () const { return (PcDesc*)(header_begin() + _dependencies_offset) ; }
300 address dependencies_begin () const { return header_begin() + _dependencies_offset ; }
301 address dependencies_end () const { return header_begin() + _handler_table_offset ; }
302 address handler_table_begin () const { return header_begin() + _handler_table_offset ; }
303 address handler_table_end () const { return header_begin() + _nul_chk_table_offset ; }
304 address nul_chk_table_begin () const { return header_begin() + _nul_chk_table_offset ; }
305 address nul_chk_table_end () const { return header_begin() + _nmethod_end_offset ; }
306
307 // Sizes
308 int oops_size () const { return (address) oops_end () - (address) oops_begin (); }
309 int metadata_size () const { return (address) metadata_end () - (address) metadata_begin (); }
310 int dependencies_size () const { return dependencies_end () - dependencies_begin (); }
311
312 int oops_count() const { assert(oops_size() % oopSize == 0, ""); return (oops_size() / oopSize) + 1; }
313 int metadata_count() const { assert(metadata_size() % wordSize == 0, ""); return (metadata_size() / wordSize) + 1; }
314
315 int total_size () const;
316
317 void dec_hotness_counter() { _hotness_counter--; }
318 void set_hotness_counter(int val) { _hotness_counter = val; }
319 int hotness_counter() const { return _hotness_counter; }
320
321 // Containment
322 bool oops_contains (oop* addr) const { return oops_begin () <= addr && addr < oops_end (); }
323 bool metadata_contains (Metadata** addr) const { return metadata_begin () <= addr && addr < metadata_end (); }
324 bool scopes_data_contains (address addr) const { return scopes_data_begin () <= addr && addr < scopes_data_end (); }
325 bool scopes_pcs_contains (PcDesc* addr) const { return scopes_pcs_begin () <= addr && addr < scopes_pcs_end (); }
326
327 // entry points
328 address entry_point() const { return _entry_point; } // normal entry point
329 address verified_entry_point() const { return _verified_entry_point; } // normal entry point without class check
330 address verified_value_entry_point() const { return _verified_value_entry_point; } // value type entry point (unpack all value args) without class check
331 address verified_value_ro_entry_point() const { return _verified_value_ro_entry_point; } // value type entry point (only unpack receiver) without class check
332
333 // flag accessing and manipulation
334 bool is_not_installed() const { return _state == not_installed; }
335 bool is_in_use() const { return _state <= in_use; }
336 bool is_alive() const { return _state < zombie; }
337 bool is_not_entrant() const { return _state == not_entrant; }
338 bool is_zombie() const { return _state == zombie; }
339 bool is_unloaded() const { return _state == unloaded; }
340
341 void clear_unloading_state();
342 virtual bool is_unloading();
343 virtual void do_unloading(bool unloading_occurred);
344
345 #if INCLUDE_RTM_OPT
346 // rtm state accessing and manipulating
347 RTMState rtm_state() const { return _rtm_state; }
348 void set_rtm_state(RTMState state) { _rtm_state = state; }
349 #endif
350
351 void make_in_use() { _state = in_use; }
352 // Make the nmethod non entrant. The nmethod will continue to be
353 // alive. It is used when an uncommon trap happens. Returns true
354 // if this thread changed the state of the nmethod or false if
355 // another thread performed the transition.
356 bool make_not_entrant() {
357 assert(!method()->is_method_handle_intrinsic(), "Cannot make MH intrinsic not entrant");
358 return make_not_entrant_or_zombie(not_entrant);
359 }
360 bool make_not_used() { return make_not_entrant(); }
361 bool make_zombie() { return make_not_entrant_or_zombie(zombie); }
362
363 // used by jvmti to track if the unload event has been reported
364 bool unload_reported() { return _unload_reported; }
365 void set_unload_reported() { _unload_reported = true; }
366
367 int get_state() const {
368 return _state;
369 }
370
371 void make_unloaded();
372
373 bool has_dependencies() { return dependencies_size() != 0; }
374 void flush_dependencies(bool delete_immediately);
375 bool has_flushed_dependencies() { return _has_flushed_dependencies; }
376 void set_has_flushed_dependencies() {
377 assert(!has_flushed_dependencies(), "should only happen once");
378 _has_flushed_dependencies = 1;
379 }
380
381 int comp_level() const { return _comp_level; }
382 bool is_c1() const { return CompLevel_simple <= _comp_level && _comp_level <= CompLevel_full_profile; }
383 void unlink_from_method(bool acquire_lock);
384
385 // Support for oops in scopes and relocs:
386 // Note: index 0 is reserved for null.
387 oop oop_at(int index) const;
388 oop* oop_addr_at(int index) const { // for GC
389 // relocation indexes are biased by 1 (because 0 is reserved)
390 assert(index > 0 && index <= oops_count(), "must be a valid non-zero index");
391 assert(!_oops_are_stale, "oops are stale");
392 return &oops_begin()[index - 1];
393 }
394
395 // Support for meta data in scopes and relocs:
396 // Note: index 0 is reserved for null.
397 Metadata* metadata_at(int index) const { return index == 0 ? NULL: *metadata_addr_at(index); }
398 Metadata** metadata_addr_at(int index) const { // for GC
399 // relocation indexes are biased by 1 (because 0 is reserved)
400 assert(index > 0 && index <= metadata_count(), "must be a valid non-zero index");
401 return &metadata_begin()[index - 1];
402 }
403
404 void copy_values(GrowableArray<jobject>* oops);
405 void copy_values(GrowableArray<Metadata*>* metadata);
406
407 // Relocation support
408 private:
409 void fix_oop_relocations(address begin, address end, bool initialize_immediates);
410 inline void initialize_immediate_oop(oop* dest, jobject handle);
411
412 public:
413 void fix_oop_relocations(address begin, address end) { fix_oop_relocations(begin, end, false); }
414 void fix_oop_relocations() { fix_oop_relocations(NULL, NULL, false); }
415
416 // Sweeper support
417 long stack_traversal_mark() { return _stack_traversal_mark; }
418 void set_stack_traversal_mark(long l) { _stack_traversal_mark = l; }
419
420 // implicit exceptions support
421 address continuation_for_implicit_exception(address pc);
422
423 // On-stack replacement support
424 int osr_entry_bci() const { assert(is_osr_method(), "wrong kind of nmethod"); return _entry_bci; }
425 address osr_entry() const { assert(is_osr_method(), "wrong kind of nmethod"); return _osr_entry_point; }
426 void invalidate_osr_method();
427 nmethod* osr_link() const { return _osr_link; }
428 void set_osr_link(nmethod *n) { _osr_link = n; }
429
430 // Verify calls to dead methods have been cleaned.
431 void verify_clean_inline_caches();
432
433 // unlink and deallocate this nmethod
434 // Only NMethodSweeper class is expected to use this. NMethodSweeper is not
435 // expected to use any other private methods/data in this class.
436
437 protected:
438 void flush();
439
440 public:
441 // When true is returned, it is unsafe to remove this nmethod even if
442 // it is a zombie, since the VM or the ServiceThread might still be
443 // using it.
444 bool is_locked_by_vm() const { return _lock_count >0; }
445
446 // See comment at definition of _last_seen_on_stack
447 void mark_as_seen_on_stack();
448 bool can_convert_to_zombie();
449
450 // Evolution support. We make old (discarded) compiled methods point to new Method*s.
451 void set_method(Method* method) { _method = method; }
452
453 #if INCLUDE_JVMCI
454 // Gets the InstalledCode object associated with this nmethod
455 // which may be NULL if this nmethod was not compiled by JVMCI
456 // or the weak reference has been cleared.
457 oop jvmci_installed_code();
458
459 // Copies the value of the name field in the InstalledCode
460 // object (if any) associated with this nmethod into buf.
461 // Returns the value of buf if it was updated otherwise NULL.
462 char* jvmci_installed_code_name(char* buf, size_t buflen) const;
463
464 // Updates the state of the InstalledCode (if any) associated with
465 // this nmethod based on the current value of _state.
466 void maybe_invalidate_installed_code();
467
468 // Deoptimizes the nmethod (if any) in the address field of a given
469 // InstalledCode object. The address field is zeroed upon return.
470 static void invalidate_installed_code(Handle installed_code, TRAPS);
471
472 // Gets the SpeculationLog object associated with this nmethod
473 // which may be NULL if this nmethod was not compiled by JVMCI
474 // or the weak reference has been cleared.
475 oop speculation_log();
476
477 private:
478 // Deletes the weak reference (if any) to the InstalledCode object
479 // associated with this nmethod.
480 void clear_jvmci_installed_code();
481
482 // Deletes the weak reference (if any) to the SpeculationLog object
483 // associated with this nmethod.
484 void clear_speculation_log();
485
486 public:
487 #endif
488
489 public:
490 void oops_do(OopClosure* f) { oops_do(f, false); }
491 void oops_do(OopClosure* f, bool allow_zombie);
492
493 bool test_set_oops_do_mark();
494 static void oops_do_marking_prologue();
495 static void oops_do_marking_epilogue();
496 static bool oops_do_marking_is_active() { return _oops_do_mark_nmethods != NULL; }
497 bool test_oops_do_mark() { return _oops_do_mark_link != NULL; }
498
499 private:
500 ScopeDesc* scope_desc_in(address begin, address end);
501
502 address* orig_pc_addr(const frame* fr);
503
504 public:
505 // copying of debugging information
506 void copy_scopes_pcs(PcDesc* pcs, int count);
507 void copy_scopes_data(address buffer, int size);
508
509 // Accessor/mutator for the original pc of a frame before a frame was deopted.
510 address get_original_pc(const frame* fr) { return *orig_pc_addr(fr); }
511 void set_original_pc(const frame* fr, address pc) { *orig_pc_addr(fr) = pc; }
512
513 // jvmti support:
514 void post_compiled_method_load_event();
515 jmethodID get_and_cache_jmethod_id();
516
517 // verify operations
518 void verify();
519 void verify_scopes();
520 void verify_interrupt_point(address interrupt_point);
521
522 // printing support
523 void print() const;
524 void print_relocations() PRODUCT_RETURN;
525 void print_pcs() PRODUCT_RETURN;
526 void print_scopes() PRODUCT_RETURN;
527 void print_dependencies() PRODUCT_RETURN;
528 void print_value_on(outputStream* st) const PRODUCT_RETURN;
529 void print_calls(outputStream* st) PRODUCT_RETURN;
530 void print_handler_table() PRODUCT_RETURN;
531 void print_nul_chk_table() PRODUCT_RETURN;
532 void print_recorded_oops() PRODUCT_RETURN;
533 void print_recorded_metadata() PRODUCT_RETURN;
534
535 void maybe_print_nmethod(DirectiveSet* directive);
536 void print_nmethod(bool print_code);
537
538 // need to re-define this from CodeBlob else the overload hides it
539 virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
540 void print_on(outputStream* st, const char* msg) const;
541
542 // Logging
543 void log_identity(xmlStream* log) const;
544 void log_new_nmethod() const;
545 void log_state_change() const;
546
547 // Prints block-level comments, including nmethod specific block labels:
548 virtual void print_block_comment(outputStream* stream, address block_begin) const {
549 print_nmethod_labels(stream, block_begin);
550 CodeBlob::print_block_comment(stream, block_begin);
551 }
552 void print_nmethod_labels(outputStream* stream, address block_begin) const;
553 void print_entry_parameters(outputStream* stream, address block_begin) const;
554
555 // Prints a comment for one native instruction (reloc info, pc desc)
556 void print_code_comment_on(outputStream* st, int column, address begin, address end);
557 static void print_statistics() PRODUCT_RETURN;
558
559 // Compiler task identification. Note that all OSR methods
560 // are numbered in an independent sequence if CICountOSR is true,
561 // and native method wrappers are also numbered independently if
562 // CICountNative is true.
563 virtual int compile_id() const { return _compile_id; }
564 const char* compile_kind() const;
565
566 // tells if any of this method's dependencies have been invalidated
567 // (this is expensive!)
568 static void check_all_dependencies(DepChange& changes);
569
570 // tells if this compiled method is dependent on the given changes,
571 // and the changes have invalidated it
572 bool check_dependency_on(DepChange& changes);
573
574 // Fast breakpoint support. Tells if this compiled method is
575 // dependent on the given method. Returns true if this nmethod
576 // corresponds to the given method as well.
577 virtual bool is_dependent_on_method(Method* dependee);
578
579 // is it ok to patch at address?
580 bool is_patchable_at(address instr_address);
581
582 // UseBiasedLocking support
583 ByteSize native_receiver_sp_offset() {
584 return _native_receiver_sp_offset;
585 }
586 ByteSize native_basic_lock_sp_offset() {
587 return _native_basic_lock_sp_offset;
588 }
589
590 // support for code generation
591 static int verified_entry_point_offset() { return offset_of(nmethod, _verified_entry_point); }
592 static int osr_entry_point_offset() { return offset_of(nmethod, _osr_entry_point); }
593 static int state_offset() { return offset_of(nmethod, _state); }
594
595 virtual void metadata_do(MetadataClosure* f);
596
597 NativeCallWrapper* call_wrapper_at(address call) const;
598 NativeCallWrapper* call_wrapper_before(address return_pc) const;
599 address call_instruction_address(address pc) const;
600
601 virtual CompiledStaticCall* compiledStaticCall_at(Relocation* call_site) const;
602 virtual CompiledStaticCall* compiledStaticCall_at(address addr) const;
603 virtual CompiledStaticCall* compiledStaticCall_before(address addr) const;
604 };
605
606 // Locks an nmethod so its code will not get removed and it will not
607 // be made into a zombie, even if it is a not_entrant method. After the
608 // nmethod becomes a zombie, if CompiledMethodUnload event processing
609 // needs to be done, then lock_nmethod() is used directly to keep the
610 // generated code from being reused too early.
611 class nmethodLocker : public StackObj {
612 CompiledMethod* _nm;
613
614 public:
615
616 // note: nm can be NULL
617 // Only JvmtiDeferredEvent::compiled_method_unload_event()
618 // should pass zombie_ok == true.
619 static void lock_nmethod(CompiledMethod* nm, bool zombie_ok = false);
620 static void unlock_nmethod(CompiledMethod* nm); // (ditto)
621
622 nmethodLocker(address pc); // derive nm from pc
623 nmethodLocker(nmethod *nm) { _nm = nm; lock_nmethod(_nm); }
624 nmethodLocker(CompiledMethod *nm) {
625 _nm = nm;
626 lock(_nm);
627 }
628
629 static void lock(CompiledMethod* method) {
630 if (method == NULL) return;
631 lock_nmethod(method);
632 }
633
634 static void unlock(CompiledMethod* method) {
635 if (method == NULL) return;
636 unlock_nmethod(method);
637 }
638
639 nmethodLocker() { _nm = NULL; }
640 ~nmethodLocker() {
641 unlock(_nm);
642 }
643
644 CompiledMethod* code() { return _nm; }
645 void set_code(CompiledMethod* new_nm) {
646 unlock(_nm); // note: This works even if _nm==new_nm.
647 _nm = new_nm;
648 lock(_nm);
649 }
650 };
651
652 #endif // SHARE_CODE_NMETHOD_HPP