1/*
2 * Copyright (c) 1998, 2016, 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.
22 *
23 */
24
25#ifndef SHARE_VM_CODE_CODEBLOB_HPP
26#define SHARE_VM_CODE_CODEBLOB_HPP
27
28#include "asm/codeBuffer.hpp"
29#include "compiler/compilerDefinitions.hpp"
30#include "compiler/oopMap.hpp"
31#include "runtime/frame.hpp"
32#include "runtime/handles.hpp"
33#include "utilities/align.hpp"
34#include "utilities/macros.hpp"
35
36// CodeBlob Types
37// Used in the CodeCache to assign CodeBlobs to different CodeHeaps
38struct CodeBlobType {
39  enum {
40    MethodNonProfiled   = 0,    // Execution level 1 and 4 (non-profiled) nmethods (including native nmethods)
41    MethodProfiled      = 1,    // Execution level 2 and 3 (profiled) nmethods
42    NonNMethod          = 2,    // Non-nmethods like Buffers, Adapters and Runtime Stubs
43    All                 = 3,    // All types (No code cache segmentation)
44    AOT                 = 4,    // AOT methods
45    NumTypes            = 5     // Number of CodeBlobTypes
46  };
47};
48
49// CodeBlob - superclass for all entries in the CodeCache.
50//
51// Subtypes are:
52//   CompiledMethod       : Compiled Java methods (include method that calls to native code)
53//     nmethod            : JIT Compiled Java methods
54//   RuntimeBlob          : Non-compiled method code; generated glue code
55//     RuntimeStub        : Call to VM runtime methods
56//     DeoptimizationBlob : Used for deoptimization
57//     ExceptionBlob      : Used for stack unrolling
58//     SafepointBlob      : Used to handle illegal instruction exceptions
59//
60//
61// Layout:
62//   - header
63//   - relocation
64//   - content space
65//     - instruction space
66//   - data space
67
68
69class CodeBlobLayout;
70
71class CodeBlob VALUE_OBJ_CLASS_SPEC {
72  friend class VMStructs;
73  friend class JVMCIVMStructs;
74  friend class CodeCacheDumper;
75
76protected:
77
78  const CompilerType _type;                      // CompilerType
79  int        _size;                              // total size of CodeBlob in bytes
80  int        _header_size;                       // size of header (depends on subclass)
81  int        _frame_complete_offset;             // instruction offsets in [0.._frame_complete_offset) have
82                                                 // not finished setting up their frame. Beware of pc's in
83                                                 // that range. There is a similar range(s) on returns
84                                                 // which we don't detect.
85  int        _data_offset;                       // offset to where data region begins
86  int        _frame_size;                        // size of stack frame
87
88  address    _code_begin;
89  address    _code_end;
90  address    _content_begin;                     // address to where content region begins (this includes consts, insts, stubs)
91                                                 // address    _content_end - not required, for all CodeBlobs _code_end == _content_end for now
92  address    _data_end;
93  address    _relocation_begin;
94  address    _relocation_end;
95
96  ImmutableOopMapSet* _oop_maps;                 // OopMap for this CodeBlob
97  bool                _caller_must_gc_arguments;
98  CodeStrings         _strings;
99  const char*         _name;
100  S390_ONLY(int       _ctable_offset;)
101
102  CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, int frame_complete_offset, int frame_size, ImmutableOopMapSet* oop_maps, bool caller_must_gc_arguments);
103  CodeBlob(const char* name, CompilerType type, const CodeBlobLayout& layout, CodeBuffer* cb, int frame_complete_offset, int frame_size, OopMapSet* oop_maps, bool caller_must_gc_arguments);
104public:
105  // Returns the space needed for CodeBlob
106  static unsigned int allocation_size(CodeBuffer* cb, int header_size);
107  static unsigned int align_code_offset(int offset);
108
109  // Deletion
110  virtual void flush();
111
112  // Typing
113  virtual bool is_buffer_blob() const                 { return false; }
114  virtual bool is_nmethod() const                     { return false; }
115  virtual bool is_runtime_stub() const                { return false; }
116  virtual bool is_deoptimization_stub() const         { return false; }
117  virtual bool is_uncommon_trap_stub() const          { return false; }
118  virtual bool is_exception_stub() const              { return false; }
119  virtual bool is_safepoint_stub() const              { return false; }
120  virtual bool is_adapter_blob() const                { return false; }
121  virtual bool is_method_handles_adapter_blob() const { return false; }
122  virtual bool is_aot() const                         { return false; }
123  virtual bool is_compiled() const                    { return false; }
124
125  inline bool is_compiled_by_c1() const    { return _type == compiler_c1; };
126  inline bool is_compiled_by_c2() const    { return _type == compiler_c2; };
127  inline bool is_compiled_by_jvmci() const { return _type == compiler_jvmci; };
128  inline bool is_compiled_by_shark() const { return _type == compiler_shark; };
129  const char* compiler_name() const;
130
131  // Casting
132  nmethod* as_nmethod_or_null()                { return is_nmethod() ? (nmethod*) this : NULL; }
133  nmethod* as_nmethod()                        { assert(is_nmethod(), "must be nmethod"); return (nmethod*) this; }
134  CompiledMethod* as_compiled_method_or_null() { return is_compiled() ? (CompiledMethod*) this : NULL; }
135  CompiledMethod* as_compiled_method()         { assert(is_compiled(), "must be compiled"); return (CompiledMethod*) this; }
136  CodeBlob* as_codeblob_or_null() const        { return (CodeBlob*) this; }
137
138  // Boundaries
139  address header_begin() const        { return (address) this; }
140  relocInfo* relocation_begin() const { return (relocInfo*) _relocation_begin; };
141  relocInfo* relocation_end() const   { return (relocInfo*) _relocation_end; }
142  address content_begin() const       { return _content_begin; }
143  address content_end() const         { return _code_end; } // _code_end == _content_end is true for all types of blobs for now, it is also checked in the constructor
144  address code_begin() const          { return _code_begin;    }
145  address code_end() const            { return _code_end; }
146  address data_end() const            { return _data_end;      }
147
148  // This field holds the beginning of the const section in the old code buffer.
149  // It is needed to fix relocations of pc-relative loads when resizing the
150  // the constant pool or moving it.
151  S390_ONLY(address ctable_begin() const { return header_begin() + _ctable_offset; })
152  void set_ctable_begin(address ctable) { S390_ONLY(_ctable_offset = ctable - header_begin();) }
153
154  // Sizes
155  int size() const                               { return _size; }
156  int header_size() const                        { return _header_size; }
157  int relocation_size() const                    { return (address) relocation_end() - (address) relocation_begin(); }
158  int content_size() const                       { return           content_end()    -           content_begin();    }
159  int code_size() const                          { return           code_end()       -           code_begin();       }
160
161  // Containment
162  bool blob_contains(address addr) const         { return header_begin()       <= addr && addr < data_end();       }
163  bool code_contains(address addr) const         { return code_begin()         <= addr && addr < code_end();       }
164  bool contains(address addr) const              { return content_begin()      <= addr && addr < content_end();    }
165  bool is_frame_complete_at(address addr) const  { return _frame_complete_offset != CodeOffsets::frame_never_safe &&
166                                                          code_contains(addr) && addr >= code_begin() + _frame_complete_offset; }
167
168  // CodeCache support: really only used by the nmethods, but in order to get
169  // asserts and certain bookkeeping to work in the CodeCache they are defined
170  // virtual here.
171  virtual bool is_zombie() const                 { return false; }
172  virtual bool is_locked_by_vm() const           { return false; }
173
174  virtual bool is_unloaded() const               { return false; }
175  virtual bool is_not_entrant() const            { return false; }
176
177  // GC support
178  virtual bool is_alive() const                  = 0;
179
180  // OopMap for frame
181  ImmutableOopMapSet* oop_maps() const           { return _oop_maps; }
182  void set_oop_maps(OopMapSet* p);
183  const ImmutableOopMap* oop_map_for_return_address(address return_address);
184  virtual void preserve_callee_argument_oops(frame fr, const RegisterMap* reg_map, OopClosure* f) = 0;
185
186  // Frame support
187  int  frame_size() const                        { return _frame_size; }
188  void set_frame_size(int size)                  { _frame_size = size; }
189
190  // Returns true, if the next frame is responsible for GC'ing oops passed as arguments
191  bool caller_must_gc_arguments(JavaThread* thread) const { return _caller_must_gc_arguments; }
192
193  // Naming
194  const char* name() const                       { return _name; }
195  void set_name(const char* name)                { _name = name; }
196
197  // Debugging
198  virtual void verify() = 0;
199  virtual void print() const                     { print_on(tty); };
200  virtual void print_on(outputStream* st) const;
201  virtual void print_value_on(outputStream* st) const;
202  void print_code();
203
204  // Print the comment associated with offset on stream, if there is one
205  virtual void print_block_comment(outputStream* stream, address block_begin) const {
206    intptr_t offset = (intptr_t)(block_begin - code_begin());
207    _strings.print_block_comment(stream, offset);
208  }
209
210  // Transfer ownership of comments to this CodeBlob
211  void set_strings(CodeStrings& strings) {
212    assert(!is_aot(), "invalid on aot");
213    _strings.assign(strings);
214  }
215
216  static ByteSize name_field_offset() {
217    return byte_offset_of(CodeBlob, _name);
218  }
219
220  static ByteSize oop_maps_field_offset() {
221    return byte_offset_of(CodeBlob, _oop_maps);
222  }
223};
224
225class CodeBlobLayout : public StackObj {
226private:
227  int _size;
228  int _header_size;
229  int _relocation_size;
230  int _content_offset;
231  int _code_offset;
232  int _data_offset;
233  address _code_begin;
234  address _code_end;
235  address _content_begin;
236  address _content_end;
237  address _data_end;
238  address _relocation_begin;
239  address _relocation_end;
240
241public:
242  CodeBlobLayout(address code_begin, address code_end, address content_begin, address content_end, address data_end, address relocation_begin, address relocation_end) :
243    _size(0),
244    _header_size(0),
245    _relocation_size(0),
246    _content_offset(0),
247    _code_offset(0),
248    _data_offset(0),
249    _content_begin(content_begin),
250    _content_end(content_end),
251    _code_begin(code_begin),
252    _code_end(code_end),
253    _data_end(data_end),
254    _relocation_begin(relocation_begin),
255    _relocation_end(relocation_end)
256  {
257  }
258
259  CodeBlobLayout(const address start, int size, int header_size, int relocation_size, int data_offset) :
260    _size(size),
261    _header_size(header_size),
262    _relocation_size(relocation_size),
263    _content_offset(CodeBlob::align_code_offset(_header_size + _relocation_size)),
264    _code_offset(_content_offset),
265    _data_offset(data_offset)
266  {
267    assert(is_aligned(_relocation_size, oopSize), "unaligned size");
268
269    _code_begin = (address) start + _code_offset;
270    _code_end = (address) start + _data_offset;
271
272    _content_begin = (address) start + _content_offset;
273    _content_end = (address) start + _data_offset;
274
275    _data_end = (address) start + _size;
276    _relocation_begin = (address) start + _header_size;
277    _relocation_end = _relocation_begin + _relocation_size;
278  }
279
280  CodeBlobLayout(const address start, int size, int header_size, const CodeBuffer* cb) :
281    _size(size),
282    _header_size(header_size),
283    _relocation_size(align_up(cb->total_relocation_size(), oopSize)),
284    _content_offset(CodeBlob::align_code_offset(_header_size + _relocation_size)),
285    _code_offset(_content_offset + cb->total_offset_of(cb->insts())),
286    _data_offset(_content_offset + align_up(cb->total_content_size(), oopSize))
287  {
288    assert(is_aligned(_relocation_size, oopSize), "unaligned size");
289
290    _code_begin = (address) start + _code_offset;
291    _code_end = (address) start + _data_offset;
292
293    _content_begin = (address) start + _content_offset;
294    _content_end = (address) start + _data_offset;
295
296    _data_end = (address) start + _size;
297    _relocation_begin = (address) start + _header_size;
298    _relocation_end = _relocation_begin + _relocation_size;
299  }
300
301  int size() const { return _size; }
302  int header_size() const { return _header_size; }
303  int relocation_size() const { return _relocation_size; }
304  int content_offset() const { return _content_offset; }
305  int code_offset() const { return _code_offset; }
306  int data_offset() const { return _data_offset; }
307  address code_begin() const { return _code_begin; }
308  address code_end() const { return _code_end; }
309  address data_end() const { return _data_end; }
310  address relocation_begin() const { return _relocation_begin; }
311  address relocation_end() const { return _relocation_end; }
312  address content_begin() const { return _content_begin; }
313  address content_end() const { return _content_end; }
314};
315
316
317class RuntimeBlob : public CodeBlob {
318  friend class VMStructs;
319 public:
320
321  // Creation
322  // a) simple CodeBlob
323  // frame_complete is the offset from the beginning of the instructions
324  // to where the frame setup (from stackwalk viewpoint) is complete.
325  RuntimeBlob(const char* name, int header_size, int size, int frame_complete, int locs_size);
326
327  // b) full CodeBlob
328  RuntimeBlob(
329    const char* name,
330    CodeBuffer* cb,
331    int         header_size,
332    int         size,
333    int         frame_complete,
334    int         frame_size,
335    OopMapSet*  oop_maps,
336    bool        caller_must_gc_arguments = false
337  );
338
339  // GC support
340  virtual bool is_alive() const                  = 0;
341
342  void verify();
343
344  // OopMap for frame
345  virtual void preserve_callee_argument_oops(frame fr, const RegisterMap* reg_map, OopClosure* f)  { ShouldNotReachHere(); }
346
347  // Debugging
348  void print() const                             { print_on(tty); }
349  virtual void print_on(outputStream* st) const { CodeBlob::print_on(st); }
350  virtual void print_value_on(outputStream* st) const { CodeBlob::print_value_on(st); }
351
352  // Deal with Disassembler, VTune, Forte, JvmtiExport, MemoryService.
353  static void trace_new_stub(RuntimeBlob* blob, const char* name1, const char* name2 = "");
354};
355
356class WhiteBox;
357//----------------------------------------------------------------------------------------------------
358// BufferBlob: used to hold non-relocatable machine code such as the interpreter, stubroutines, etc.
359
360class BufferBlob: public RuntimeBlob {
361  friend class VMStructs;
362  friend class AdapterBlob;
363  friend class MethodHandlesAdapterBlob;
364  friend class WhiteBox;
365
366 private:
367  // Creation support
368  BufferBlob(const char* name, int size);
369  BufferBlob(const char* name, int size, CodeBuffer* cb);
370
371  void* operator new(size_t s, unsigned size) throw();
372
373 public:
374  // Creation
375  static BufferBlob* create(const char* name, int buffer_size);
376  static BufferBlob* create(const char* name, CodeBuffer* cb);
377
378  static void free(BufferBlob* buf);
379
380  // Typing
381  virtual bool is_buffer_blob() const            { return true; }
382
383  // GC/Verification support
384  void preserve_callee_argument_oops(frame fr, const RegisterMap* reg_map, OopClosure* f)  { /* nothing to do */ }
385  bool is_alive() const                          { return true; }
386
387  void verify();
388  void print_on(outputStream* st) const;
389  void print_value_on(outputStream* st) const;
390};
391
392
393//----------------------------------------------------------------------------------------------------
394// AdapterBlob: used to hold C2I/I2C adapters
395
396class AdapterBlob: public BufferBlob {
397private:
398  AdapterBlob(int size, CodeBuffer* cb);
399
400public:
401  // Creation
402  static AdapterBlob* create(CodeBuffer* cb);
403
404  // Typing
405  virtual bool is_adapter_blob() const { return true; }
406};
407
408
409//----------------------------------------------------------------------------------------------------
410// MethodHandlesAdapterBlob: used to hold MethodHandles adapters
411
412class MethodHandlesAdapterBlob: public BufferBlob {
413private:
414  MethodHandlesAdapterBlob(int size)                 : BufferBlob("MethodHandles adapters", size) {}
415
416public:
417  // Creation
418  static MethodHandlesAdapterBlob* create(int buffer_size);
419
420  // Typing
421  virtual bool is_method_handles_adapter_blob() const { return true; }
422};
423
424
425//----------------------------------------------------------------------------------------------------
426// RuntimeStub: describes stubs used by compiled code to call a (static) C++ runtime routine
427
428class RuntimeStub: public RuntimeBlob {
429  friend class VMStructs;
430 private:
431  // Creation support
432  RuntimeStub(
433    const char* name,
434    CodeBuffer* cb,
435    int         size,
436    int         frame_complete,
437    int         frame_size,
438    OopMapSet*  oop_maps,
439    bool        caller_must_gc_arguments
440  );
441
442  void* operator new(size_t s, unsigned size) throw();
443
444 public:
445  // Creation
446  static RuntimeStub* new_runtime_stub(
447    const char* stub_name,
448    CodeBuffer* cb,
449    int         frame_complete,
450    int         frame_size,
451    OopMapSet*  oop_maps,
452    bool        caller_must_gc_arguments
453  );
454
455  // Typing
456  bool is_runtime_stub() const                   { return true; }
457
458  address entry_point() const                    { return code_begin(); }
459
460  // GC/Verification support
461  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f)  { /* nothing to do */ }
462  bool is_alive() const                          { return true; }
463
464  void verify();
465  void print_on(outputStream* st) const;
466  void print_value_on(outputStream* st) const;
467};
468
469
470//----------------------------------------------------------------------------------------------------
471// Super-class for all blobs that exist in only one instance. Implements default behaviour.
472
473class SingletonBlob: public RuntimeBlob {
474  friend class VMStructs;
475
476 protected:
477  void* operator new(size_t s, unsigned size) throw();
478
479 public:
480   SingletonBlob(
481     const char* name,
482     CodeBuffer* cb,
483     int         header_size,
484     int         size,
485     int         frame_size,
486     OopMapSet*  oop_maps
487   )
488   : RuntimeBlob(name, cb, header_size, size, CodeOffsets::frame_never_safe, frame_size, oop_maps)
489  {};
490
491  address entry_point()                          { return code_begin(); }
492
493  bool is_alive() const                          { return true; }
494
495  // GC/Verification support
496  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f)  { /* nothing to do */ }
497  void verify(); // does nothing
498  void print_on(outputStream* st) const;
499  void print_value_on(outputStream* st) const;
500};
501
502
503//----------------------------------------------------------------------------------------------------
504// DeoptimizationBlob
505
506class DeoptimizationBlob: public SingletonBlob {
507  friend class VMStructs;
508  friend class JVMCIVMStructs;
509 private:
510  int _unpack_offset;
511  int _unpack_with_exception;
512  int _unpack_with_reexecution;
513
514  int _unpack_with_exception_in_tls;
515
516#if INCLUDE_JVMCI
517  // Offsets when JVMCI calls uncommon_trap.
518  int _uncommon_trap_offset;
519  int _implicit_exception_uncommon_trap_offset;
520#endif
521
522  // Creation support
523  DeoptimizationBlob(
524    CodeBuffer* cb,
525    int         size,
526    OopMapSet*  oop_maps,
527    int         unpack_offset,
528    int         unpack_with_exception_offset,
529    int         unpack_with_reexecution_offset,
530    int         frame_size
531  );
532
533 public:
534  // Creation
535  static DeoptimizationBlob* create(
536    CodeBuffer* cb,
537    OopMapSet*  oop_maps,
538    int         unpack_offset,
539    int         unpack_with_exception_offset,
540    int         unpack_with_reexecution_offset,
541    int         frame_size
542  );
543
544  // Typing
545  bool is_deoptimization_stub() const { return true; }
546  bool exception_address_is_unpack_entry(address pc) const {
547    address unpack_pc = unpack();
548    return (pc == unpack_pc || (pc + frame::pc_return_offset) == unpack_pc);
549  }
550
551  // GC for args
552  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) { /* Nothing to do */ }
553
554  // Printing
555  void print_value_on(outputStream* st) const;
556
557  address unpack() const                         { return code_begin() + _unpack_offset;           }
558  address unpack_with_exception() const          { return code_begin() + _unpack_with_exception;   }
559  address unpack_with_reexecution() const        { return code_begin() + _unpack_with_reexecution; }
560
561  // Alternate entry point for C1 where the exception and issuing pc
562  // are in JavaThread::_exception_oop and JavaThread::_exception_pc
563  // instead of being in registers.  This is needed because C1 doesn't
564  // model exception paths in a way that keeps these registers free so
565  // there may be live values in those registers during deopt.
566  void set_unpack_with_exception_in_tls_offset(int offset) {
567    _unpack_with_exception_in_tls = offset;
568    assert(code_contains(code_begin() + _unpack_with_exception_in_tls), "must be PC inside codeblob");
569  }
570  address unpack_with_exception_in_tls() const   { return code_begin() + _unpack_with_exception_in_tls; }
571
572#if INCLUDE_JVMCI
573  // Offsets when JVMCI calls uncommon_trap.
574  void set_uncommon_trap_offset(int offset) {
575    _uncommon_trap_offset = offset;
576    assert(contains(code_begin() + _uncommon_trap_offset), "must be PC inside codeblob");
577  }
578  address uncommon_trap() const                  { return code_begin() + _uncommon_trap_offset; }
579
580  void set_implicit_exception_uncommon_trap_offset(int offset) {
581    _implicit_exception_uncommon_trap_offset = offset;
582    assert(contains(code_begin() + _implicit_exception_uncommon_trap_offset), "must be PC inside codeblob");
583  }
584  address implicit_exception_uncommon_trap() const { return code_begin() + _implicit_exception_uncommon_trap_offset; }
585#endif // INCLUDE_JVMCI
586};
587
588
589//----------------------------------------------------------------------------------------------------
590// UncommonTrapBlob (currently only used by Compiler 2)
591
592#ifdef COMPILER2
593
594class UncommonTrapBlob: public SingletonBlob {
595  friend class VMStructs;
596 private:
597  // Creation support
598  UncommonTrapBlob(
599    CodeBuffer* cb,
600    int         size,
601    OopMapSet*  oop_maps,
602    int         frame_size
603  );
604
605 public:
606  // Creation
607  static UncommonTrapBlob* create(
608    CodeBuffer* cb,
609    OopMapSet*  oop_maps,
610    int         frame_size
611  );
612
613  // GC for args
614  void preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f)  { /* nothing to do */ }
615
616  // Typing
617  bool is_uncommon_trap_stub() const             { return true; }
618};
619
620
621//----------------------------------------------------------------------------------------------------
622// ExceptionBlob: used for exception unwinding in compiled code (currently only used by Compiler 2)
623
624class ExceptionBlob: public SingletonBlob {
625  friend class VMStructs;
626 private:
627  // Creation support
628  ExceptionBlob(
629    CodeBuffer* cb,
630    int         size,
631    OopMapSet*  oop_maps,
632    int         frame_size
633  );
634
635 public:
636  // Creation
637  static ExceptionBlob* create(
638    CodeBuffer* cb,
639    OopMapSet*  oop_maps,
640    int         frame_size
641  );
642
643  // GC for args
644  void preserve_callee_argument_oops(frame fr, const RegisterMap* reg_map, OopClosure* f)  { /* nothing to do */ }
645
646  // Typing
647  bool is_exception_stub() const                 { return true; }
648};
649#endif // COMPILER2
650
651
652//----------------------------------------------------------------------------------------------------
653// SafepointBlob: handles illegal_instruction exceptions during a safepoint
654
655class SafepointBlob: public SingletonBlob {
656  friend class VMStructs;
657 private:
658  // Creation support
659  SafepointBlob(
660    CodeBuffer* cb,
661    int         size,
662    OopMapSet*  oop_maps,
663    int         frame_size
664  );
665
666 public:
667  // Creation
668  static SafepointBlob* create(
669    CodeBuffer* cb,
670    OopMapSet*  oop_maps,
671    int         frame_size
672  );
673
674  // GC for args
675  void preserve_callee_argument_oops(frame fr, const RegisterMap* reg_map, OopClosure* f)  { /* nothing to do */ }
676
677  // Typing
678  bool is_safepoint_stub() const                 { return true; }
679};
680
681#endif // SHARE_VM_CODE_CODEBLOB_HPP
682