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