1 /*
2 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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).
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16 * 2 along with this work; if not, write to the Free Software Foundation,
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23 */
24
25 #ifndef SHARE_OOPS_CONSTMETHOD_HPP
26 #define SHARE_OOPS_CONSTMETHOD_HPP
27
28 #include "oops/oop.hpp"
29 #include "runtime/arguments.hpp"
30 #include "utilities/align.hpp"
31
32 // An ConstMethod represents portions of a Java method which are not written to after
33 // the classfile is parsed(*see below). This part of the method can be shared across
34 // processes in a read-only section with Class Data Sharing (CDS). It's important
35 // that this class doesn't have virtual functions because the vptr cannot be shared
36 // with CDS.
37 //
38 // Note that most applications load thousands of methods, so keeping the size of this
39 // structure small has a big impact on footprint.
40
41 // The actual bytecodes are inlined after the end of the ConstMethod struct.
42 //
43 // The line number table is compressed and inlined following the byte codes. It is
44 // found as the first byte following the byte codes. Note that accessing the line
45 // number and local variable tables is not performance critical at all.
46 //
47 // The checked exceptions table and the local variable table are inlined after the
48 // line number table, and indexed from the end of the method. We do not compress the
49 // checked exceptions table since the average length is less than 2, and it is used
50 // by reflection so access should be fast. We do not bother to compress the local
51 // variable table either since it is mostly absent.
52 //
53 //
54 // ConstMethod embedded field layout (after declared fields):
55 // [EMBEDDED byte codes]
56 // [EMBEDDED compressed linenumber table]
57 // (see class CompressedLineNumberReadStream)
58 // (note that length is unknown until decompressed)
59 // (access flags bit tells whether table is present)
60 // (indexed from start of ConstMethod)
61 // (elements not necessarily sorted!)
62 // [EMBEDDED localvariable table elements + length (length last)]
63 // (length is u2, elements are 6-tuples of u2)
64 // (see class LocalVariableTableElement)
65 // (access flags bit tells whether table is present)
66 // (indexed from end of ConstMethod*)
67 // [EMBEDDED exception table + length (length last)]
68 // (length is u2, elements are 4-tuples of u2)
69 // (see class ExceptionTableElement)
70 // (access flags bit tells whether table is present)
71 // (indexed from end of ConstMethod*)
72 // [EMBEDDED checked exceptions elements + length (length last)]
73 // (length is u2, elements are u2)
74 // (see class CheckedExceptionElement)
75 // (access flags bit tells whether table is present)
76 // (indexed from end of ConstMethod*)
77 // [EMBEDDED method parameters elements + length (length last)]
78 // (length is u2, elements are u2, u4 structures)
79 // (see class MethodParametersElement)
80 // (access flags bit tells whether table is present)
81 // (indexed from end of ConstMethod*)
82 // [EMBEDDED generic signature index (u2)]
83 // (indexed from end of constMethodOop)
84 // [EMBEDDED annotations arrays - method, parameter, type, default]
85 // pointer to Array<u1> if annotation is present
86 //
87 // IMPORTANT: If anything gets added here, there need to be changes to
88 // ensure that ServicabilityAgent doesn't get broken as a result!
89
90
91 // Utility class describing elements in checked exceptions table inlined in Method*.
92 class CheckedExceptionElement {
93 public:
94 u2 class_cp_index;
95 };
96
97
98 // Utility class describing elements in local variable table inlined in Method*.
99 class LocalVariableTableElement {
100 public:
101 u2 start_bci;
102 u2 length;
103 u2 name_cp_index;
104 u2 descriptor_cp_index;
105 u2 signature_cp_index;
106 u2 slot;
107 };
108
109 // Utility class describing elements in exception table
110 class ExceptionTableElement {
111 public:
112 u2 start_pc;
113 u2 end_pc;
114 u2 handler_pc;
115 u2 catch_type_index;
116 };
117
118 // Utility class describing elements in method parameters
119 class MethodParametersElement {
120 public:
121 u2 name_cp_index;
122 u2 flags;
123 };
124
125 class KlassSizeStats;
126 class AdapterHandlerEntry;
127
128 // Class to collect the sizes of ConstMethod inline tables
129 #define INLINE_TABLES_DO(do_element) \
130 do_element(localvariable_table_length) \
131 do_element(compressed_linenumber_size) \
132 do_element(exception_table_length) \
133 do_element(checked_exceptions_length) \
134 do_element(method_parameters_length) \
135 do_element(generic_signature_index) \
136 do_element(method_annotations_length) \
137 do_element(parameter_annotations_length) \
138 do_element(type_annotations_length) \
139 do_element(default_annotations_length)
140
141 #define INLINE_TABLE_DECLARE(sym) int _##sym;
142 #define INLINE_TABLE_PARAM(sym) int sym,
143 #define INLINE_TABLE_INIT(sym) _##sym(sym),
144 #define INLINE_TABLE_NULL(sym) _##sym(0),
145 #define INLINE_TABLE_ACCESSOR(sym) int sym() const { return _##sym; }
146
147 class InlineTableSizes : StackObj {
148 // declarations
149 INLINE_TABLES_DO(INLINE_TABLE_DECLARE)
150 int _end;
151 public:
152 InlineTableSizes(
153 INLINE_TABLES_DO(INLINE_TABLE_PARAM)
154 int end) :
155 INLINE_TABLES_DO(INLINE_TABLE_INIT)
156 _end(end) {}
157
158 // Default constructor for no inlined tables
159 InlineTableSizes() :
160 INLINE_TABLES_DO(INLINE_TABLE_NULL)
161 _end(0) {}
162
163 // Accessors
164 INLINE_TABLES_DO(INLINE_TABLE_ACCESSOR)
165 };
166 #undef INLINE_TABLE_ACCESSOR
167 #undef INLINE_TABLE_NULL
168 #undef INLINE_TABLE_INIT
169 #undef INLINE_TABLE_PARAM
170 #undef INLINE_TABLE_DECLARE
171
172 class ConstMethod : public MetaspaceObj {
173 friend class VMStructs;
174 friend class JVMCIVMStructs;
175
176 public:
177 typedef enum { NORMAL, OVERPASS } MethodType;
178
179 private:
180 enum {
181 _has_linenumber_table = 0x0001,
182 _has_checked_exceptions = 0x0002,
183 _has_localvariable_table = 0x0004,
184 _has_exception_table = 0x0008,
185 _has_generic_signature = 0x0010,
186 _has_method_parameters = 0x0020,
187 _is_overpass = 0x0040,
188 _has_method_annotations = 0x0080,
189 _has_parameter_annotations = 0x0100,
190 _has_type_annotations = 0x0200,
191 _has_default_annotations = 0x0400
192 };
193
194 // Bit vector of signature
195 // Callers interpret 0=not initialized yet and
196 // -1=too many args to fix, must parse the slow way.
197 // The real initial value is special to account for nonatomicity of 64 bit
198 // loads and stores. This value may updated and read without a lock by
199 // multiple threads, so is volatile.
200 volatile uint64_t _fingerprint;
201
202 // If you add a new field that points to any metaspace object, you
203 // must add this field to ConstMethod::metaspace_pointers_do().
204
205 ConstantPool* _constants; // Constant pool
206
207 // Raw stackmap data for the method
208 Array<u1>* _stackmap_data;
209
210 // Adapter blob (i2c/c2i) for this Method*. Set once when method is linked.
211 union {
212 AdapterHandlerEntry* _adapter;
213 AdapterHandlerEntry** _adapter_trampoline; // see comments around Method::link_method()
214 };
215
216 int _constMethod_size;
217 u2 _flags;
218 u1 _result_type; // BasicType of result
219
220 // Size of Java bytecodes allocated immediately after Method*.
221 u2 _code_size;
222 u2 _name_index; // Method name (index in constant pool)
223 u2 _signature_index; // Method signature (index in constant pool)
224 u2 _method_idnum; // unique identification number for the method within the class
225 // initially corresponds to the index into the methods array.
226 // but this may change with redefinition
227 u2 _max_stack; // Maximum number of entries on the expression stack
228 u2 _max_locals; // Number of local variables used by this method
229 u2 _size_of_parameters; // size of the parameter block (receiver + arguments) in words
230 u2 _orig_method_idnum; // Original unique identification number for the method
231
232 // Constructor
233 ConstMethod(int byte_code_size,
234 InlineTableSizes* sizes,
235 MethodType is_overpass,
236 int size);
237 public:
238
239 static ConstMethod* allocate(ClassLoaderData* loader_data,
240 int byte_code_size,
241 InlineTableSizes* sizes,
242 MethodType mt,
243 TRAPS);
244
245 // Inlined tables
246 void set_inlined_tables_length(InlineTableSizes* sizes);
247
248 bool has_generic_signature() const
249 { return (_flags & _has_generic_signature) != 0; }
250
251 bool has_linenumber_table() const
252 { return (_flags & _has_linenumber_table) != 0; }
253
254 bool has_checked_exceptions() const
255 { return (_flags & _has_checked_exceptions) != 0; }
256
257 bool has_localvariable_table() const
258 { return (_flags & _has_localvariable_table) != 0; }
259
260 bool has_exception_handler() const
261 { return (_flags & _has_exception_table) != 0; }
262
263 bool has_method_parameters() const
264 { return (_flags & _has_method_parameters) != 0; }
265
266 MethodType method_type() const {
267 return ((_flags & _is_overpass) == 0) ? NORMAL : OVERPASS;
268 }
269
270 void set_method_type(MethodType mt) {
271 if (mt == NORMAL) {
272 _flags &= ~(_is_overpass);
273 } else {
274 _flags |= _is_overpass;
275 }
276 }
277
278 // constant pool
279 ConstantPool* constants() const { return _constants; }
280 void set_constants(ConstantPool* c) { _constants = c; }
281
282 Method* method() const;
283
284 // stackmap table data
285 Array<u1>* stackmap_data() const { return _stackmap_data; }
286 void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; }
287 void copy_stackmap_data(ClassLoaderData* loader_data, u1* sd, int length, TRAPS);
288 bool has_stackmap_table() const { return _stackmap_data != NULL; }
289
290 // adapter
291 void set_adapter_entry(AdapterHandlerEntry* adapter) {
292 assert(!is_shared(),
293 "shared methods in archive have fixed adapter_trampoline");
294 _adapter = adapter;
295 }
296 void set_adapter_trampoline(AdapterHandlerEntry** trampoline) {
297 Arguments::assert_is_dumping_archive();
298 if (DumpSharedSpaces) {
299 assert(*trampoline == NULL,
300 "must be NULL during dump time, to be initialized at run time");
301 }
302 _adapter_trampoline = trampoline;
303 }
304 void update_adapter_trampoline(AdapterHandlerEntry* adapter) {
305 assert(is_shared(), "must be");
306 *_adapter_trampoline = adapter;
307 assert(this->adapter() == adapter, "must be");
308 }
309 AdapterHandlerEntry* adapter() {
310 if (is_shared()) {
311 return *_adapter_trampoline;
312 } else {
313 return _adapter;
314 }
315 }
316
317 void init_fingerprint() {
318 const uint64_t initval = UCONST64(0x8000000000000000);
319 _fingerprint = initval;
320 }
321
322 uint64_t fingerprint() const {
323 // Since reads aren't atomic for 64 bits, if any of the high or low order
324 // word is the initial value, return 0. See init_fingerprint for initval.
325 uint high_fp = (uint)(_fingerprint >> 32);
326 if ((int) _fingerprint == 0 || high_fp == 0x80000000) {
327 return 0L;
328 } else {
329 return _fingerprint;
330 }
331 }
332
333 uint64_t set_fingerprint(uint64_t new_fingerprint) {
334 #ifdef ASSERT
335 // Assert only valid if complete/valid 64 bit _fingerprint value is read.
336 uint64_t oldfp = fingerprint();
337 #endif // ASSERT
338 _fingerprint = new_fingerprint;
339 assert(oldfp == 0L || new_fingerprint == oldfp,
340 "fingerprint cannot change");
341 assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,
342 "fingerprint should call init to set initial value");
343 return new_fingerprint;
344 }
345
346 // name
347 int name_index() const { return _name_index; }
348 void set_name_index(int index) { _name_index = index; }
349
350 // signature
351 int signature_index() const { return _signature_index; }
352 void set_signature_index(int index) { _signature_index = index; }
353
354 // generics support
355 int generic_signature_index() const {
356 if (has_generic_signature()) {
357 return *generic_signature_index_addr();
358 } else {
359 return 0;
360 }
361 }
362 void set_generic_signature_index(u2 index) {
363 assert(has_generic_signature(), "");
364 u2* addr = generic_signature_index_addr();
365 *addr = index;
366 }
367
368 // Sizing
369 static int header_size() {
370 return align_up((int)sizeof(ConstMethod), wordSize) / wordSize;
371 }
372
373 // Size needed
374 static int size(int code_size, InlineTableSizes* sizes);
375
376 int size() const { return _constMethod_size;}
377 void set_constMethod_size(int size) { _constMethod_size = size; }
378
379 // ConstMethods should be stored in the read-only region of CDS archive.
380 static bool is_read_only_by_default() { return true; }
381
382 #if INCLUDE_SERVICES
383 void collect_statistics(KlassSizeStats *sz) const;
384 #endif
385
386 // code size
387 int code_size() const { return _code_size; }
388 void set_code_size(int size) {
389 assert(max_method_code_size < (1 << 16),
390 "u2 is too small to hold method code size in general");
391 assert(0 <= size && size <= max_method_code_size, "invalid code size");
392 _code_size = size;
393 }
394
395 // linenumber table - note that length is unknown until decompression,
396 // see class CompressedLineNumberReadStream.
397 u_char* compressed_linenumber_table() const; // not preserved by gc
398 u2* generic_signature_index_addr() const;
399 u2* checked_exceptions_length_addr() const;
400 u2* localvariable_table_length_addr() const;
401 u2* exception_table_length_addr() const;
402 u2* method_parameters_length_addr() const;
403
404 // checked exceptions
405 int checked_exceptions_length() const;
406 CheckedExceptionElement* checked_exceptions_start() const;
407
408 // localvariable table
409 int localvariable_table_length() const;
410 LocalVariableTableElement* localvariable_table_start() const;
411
412 // exception table
413 int exception_table_length() const;
414 ExceptionTableElement* exception_table_start() const;
415
416 // method parameters table
417
418 // This returns -1 if no parameters are present, a non-negative
419 // value otherwise. Note: sometimes, there are 0-length parameters
420 // attributes that must be reported up to the reflection API all the
421 // same.
422 int method_parameters_length() const;
423 MethodParametersElement* method_parameters_start() const;
424
425 // method annotations
426 bool has_method_annotations() const
427 { return (_flags & _has_method_annotations) != 0; }
428
429 bool has_parameter_annotations() const
430 { return (_flags & _has_parameter_annotations) != 0; }
431
432 bool has_type_annotations() const
433 { return (_flags & _has_type_annotations) != 0; }
434
435 bool has_default_annotations() const
436 { return (_flags & _has_default_annotations) != 0; }
437
438
439 AnnotationArray** method_annotations_addr() const;
440 AnnotationArray* method_annotations() const {
441 return has_method_annotations() ? *(method_annotations_addr()) : NULL;
442 }
443 void set_method_annotations(AnnotationArray* anno) {
444 *(method_annotations_addr()) = anno;
445 }
446
447 AnnotationArray** parameter_annotations_addr() const;
448 AnnotationArray* parameter_annotations() const {
449 return has_parameter_annotations() ? *(parameter_annotations_addr()) : NULL;
450 }
451 void set_parameter_annotations(AnnotationArray* anno) {
452 *(parameter_annotations_addr()) = anno;
453 }
454
455 AnnotationArray** type_annotations_addr() const;
456 AnnotationArray* type_annotations() const {
457 return has_type_annotations() ? *(type_annotations_addr()) : NULL;
458 }
459 void set_type_annotations(AnnotationArray* anno) {
460 *(type_annotations_addr()) = anno;
461 }
462
463 AnnotationArray** default_annotations_addr() const;
464 AnnotationArray* default_annotations() const {
465 return has_default_annotations() ? *(default_annotations_addr()) : NULL;
466 }
467 void set_default_annotations(AnnotationArray* anno) {
468 *(default_annotations_addr()) = anno;
469 }
470
471 int method_annotations_length() const {
472 return has_method_annotations() ? method_annotations()->length() : 0;
473 }
474 int parameter_annotations_length() const {
475 return has_parameter_annotations() ? parameter_annotations()->length() : 0;
476 }
477 int type_annotations_length() const {
478 return has_type_annotations() ? type_annotations()->length() : 0;
479 }
480 int default_annotations_length() const {
481 return has_default_annotations() ? default_annotations()->length() : 0;
482 }
483
484 // Copy annotations from other ConstMethod
485 void copy_annotations_from(ClassLoaderData* loader_data, ConstMethod* cm, TRAPS);
486
487 // byte codes
488 void set_code(address code) {
489 if (code_size() > 0) {
490 memcpy(code_base(), code, code_size());
491 }
492 }
493 address code_base() const { return (address) (this+1); }
494 address code_end() const { return code_base() + code_size(); }
495 bool contains(address bcp) const { return code_base() <= bcp
496 && bcp < code_end(); }
497 // Offset to bytecodes
498 static ByteSize codes_offset()
499 { return in_ByteSize(sizeof(ConstMethod)); }
500
501 static ByteSize constants_offset()
502 { return byte_offset_of(ConstMethod, _constants); }
503
504 static ByteSize max_stack_offset()
505 { return byte_offset_of(ConstMethod, _max_stack); }
506 static ByteSize size_of_locals_offset()
507 { return byte_offset_of(ConstMethod, _max_locals); }
508 static ByteSize size_of_parameters_offset()
509 { return byte_offset_of(ConstMethod, _size_of_parameters); }
510
511 static ByteSize result_type_offset()
512 { return byte_offset_of(ConstMethod, _result_type); }
513
514 // Unique id for the method
515 static const u2 MAX_IDNUM;
516 static const u2 UNSET_IDNUM;
517 u2 method_idnum() const { return _method_idnum; }
518 void set_method_idnum(u2 idnum) { _method_idnum = idnum; }
519
520 u2 orig_method_idnum() const { return _orig_method_idnum; }
521 void set_orig_method_idnum(u2 idnum) { _orig_method_idnum = idnum; }
522
523 // max stack
524 int max_stack() const { return _max_stack; }
525 void set_max_stack(int size) { _max_stack = size; }
526
527 // max locals
528 int max_locals() const { return _max_locals; }
529 void set_max_locals(int size) { _max_locals = size; }
530
531 // size of parameters
532 int size_of_parameters() const { return _size_of_parameters; }
533 void set_size_of_parameters(int size) { _size_of_parameters = size; }
534
535 void set_result_type(BasicType rt) { assert(rt < 16, "result type too large");
536 _result_type = (u1)rt; }
537 // Deallocation for RedefineClasses
538 void deallocate_contents(ClassLoaderData* loader_data);
539 bool is_klass() const { return false; }
540 DEBUG_ONLY(bool on_stack() { return false; })
541
542 void metaspace_pointers_do(MetaspaceClosure* it);
543 MetaspaceObj::Type type() const { return ConstMethodType; }
544 private:
545 // Since the size of the compressed line number table is unknown, the
546 // offsets of the other variable sized sections are computed backwards
547 // from the end of the ConstMethod*.
548
549 // First byte after ConstMethod*
550 address constMethod_end() const
551 { return (address)((intptr_t*)this + _constMethod_size); }
552
553 // Last short in ConstMethod*
554 u2* last_u2_element() const;
555
556 public:
557 // Printing
558 void print_on (outputStream* st) const;
559 void print_value_on(outputStream* st) const;
560
561 const char* internal_name() const { return "{constMethod}"; }
562
563 // Verify
564 void verify_on(outputStream* st);
565 };
566
567 #endif // SHARE_OOPS_CONSTMETHOD_HPP