1 /* 2 * Copyright (c) 2003, 2021, 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_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 to collect the sizes of ConstMethod inline tables 125 #define INLINE_TABLES_DO(do_element) \ 126 do_element(localvariable_table_length) \ 127 do_element(compressed_linenumber_size) \ 128 do_element(exception_table_length) \ 129 do_element(checked_exceptions_length) \ 130 do_element(method_parameters_length) \ 131 do_element(generic_signature_index) \ 132 do_element(method_annotations_length) \ 133 do_element(parameter_annotations_length) \ 134 do_element(type_annotations_length) \ 135 do_element(default_annotations_length) 136 137 #define INLINE_TABLE_DECLARE(sym) int _##sym; 138 #define INLINE_TABLE_PARAM(sym) int sym, 139 #define INLINE_TABLE_INIT(sym) _##sym(sym), 140 #define INLINE_TABLE_NULL(sym) _##sym(0), 141 #define INLINE_TABLE_ACCESSOR(sym) int sym() const { return _##sym; } 142 143 class InlineTableSizes : StackObj { 144 // declarations 145 INLINE_TABLES_DO(INLINE_TABLE_DECLARE) 146 int _end; 147 public: InlineTableSizes(INLINE_TABLES_DO (INLINE_TABLE_PARAM)int end)148 InlineTableSizes( 149 INLINE_TABLES_DO(INLINE_TABLE_PARAM) 150 int end) : 151 INLINE_TABLES_DO(INLINE_TABLE_INIT) 152 _end(end) {} 153 154 // Default constructor for no inlined tables InlineTableSizes()155 InlineTableSizes() : 156 INLINE_TABLES_DO(INLINE_TABLE_NULL) 157 _end(0) {} 158 159 // Accessors 160 INLINE_TABLES_DO(INLINE_TABLE_ACCESSOR) 161 }; 162 #undef INLINE_TABLE_ACCESSOR 163 #undef INLINE_TABLE_NULL 164 #undef INLINE_TABLE_INIT 165 #undef INLINE_TABLE_PARAM 166 #undef INLINE_TABLE_DECLARE 167 168 class ConstMethod : public MetaspaceObj { 169 friend class VMStructs; 170 friend class JVMCIVMStructs; 171 172 public: 173 typedef enum { NORMAL, OVERPASS } MethodType; 174 175 private: 176 enum { 177 _has_linenumber_table = 0x0001, 178 _has_checked_exceptions = 0x0002, 179 _has_localvariable_table = 0x0004, 180 _has_exception_table = 0x0008, 181 _has_generic_signature = 0x0010, 182 _has_method_parameters = 0x0020, 183 _is_overpass = 0x0040, 184 _has_method_annotations = 0x0080, 185 _has_parameter_annotations = 0x0100, 186 _has_type_annotations = 0x0200, 187 _has_default_annotations = 0x0400 188 }; 189 190 // Bit vector of signature 191 // Callers interpret 0=not initialized yet and 192 // -1=too many args to fix, must parse the slow way. 193 // The real initial value is special to account for nonatomicity of 64 bit 194 // loads and stores. This value may updated and read without a lock by 195 // multiple threads, so is volatile. 196 volatile uint64_t _fingerprint; 197 198 // If you add a new field that points to any metaspace object, you 199 // must add this field to ConstMethod::metaspace_pointers_do(). 200 201 ConstantPool* _constants; // Constant pool 202 203 // Raw stackmap data for the method 204 Array<u1>* _stackmap_data; 205 206 int _constMethod_size; 207 u2 _flags; 208 u1 _result_type; // BasicType of result 209 210 // Size of Java bytecodes allocated immediately after Method*. 211 u2 _code_size; 212 u2 _name_index; // Method name (index in constant pool) 213 u2 _signature_index; // Method signature (index in constant pool) 214 u2 _method_idnum; // unique identification number for the method within the class 215 // initially corresponds to the index into the methods array. 216 // but this may change with redefinition 217 u2 _max_stack; // Maximum number of entries on the expression stack 218 u2 _max_locals; // Number of local variables used by this method 219 u2 _size_of_parameters; // size of the parameter block (receiver + arguments) in words 220 u2 _orig_method_idnum; // Original unique identification number for the method 221 222 // Constructor 223 ConstMethod(int byte_code_size, 224 InlineTableSizes* sizes, 225 MethodType is_overpass, 226 int size); 227 public: 228 229 static ConstMethod* allocate(ClassLoaderData* loader_data, 230 int byte_code_size, 231 InlineTableSizes* sizes, 232 MethodType mt, 233 TRAPS); 234 235 // Inlined tables 236 void set_inlined_tables_length(InlineTableSizes* sizes); 237 has_generic_signature() const238 bool has_generic_signature() const 239 { return (_flags & _has_generic_signature) != 0; } 240 has_linenumber_table() const241 bool has_linenumber_table() const 242 { return (_flags & _has_linenumber_table) != 0; } 243 has_checked_exceptions() const244 bool has_checked_exceptions() const 245 { return (_flags & _has_checked_exceptions) != 0; } 246 has_localvariable_table() const247 bool has_localvariable_table() const 248 { return (_flags & _has_localvariable_table) != 0; } 249 has_exception_handler() const250 bool has_exception_handler() const 251 { return (_flags & _has_exception_table) != 0; } 252 has_method_parameters() const253 bool has_method_parameters() const 254 { return (_flags & _has_method_parameters) != 0; } 255 method_type() const256 MethodType method_type() const { 257 return ((_flags & _is_overpass) == 0) ? NORMAL : OVERPASS; 258 } 259 set_method_type(MethodType mt)260 void set_method_type(MethodType mt) { 261 if (mt == NORMAL) { 262 _flags &= ~(_is_overpass); 263 } else { 264 _flags |= _is_overpass; 265 } 266 } 267 268 // constant pool constants() const269 ConstantPool* constants() const { return _constants; } set_constants(ConstantPool * c)270 void set_constants(ConstantPool* c) { _constants = c; } 271 272 Method* method() const; 273 274 // stackmap table data stackmap_data() const275 Array<u1>* stackmap_data() const { return _stackmap_data; } set_stackmap_data(Array<u1> * sd)276 void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; } 277 void copy_stackmap_data(ClassLoaderData* loader_data, u1* sd, int length, TRAPS); has_stackmap_table() const278 bool has_stackmap_table() const { return _stackmap_data != NULL; } 279 init_fingerprint()280 void init_fingerprint() { 281 const uint64_t initval = UCONST64(0x8000000000000000); 282 _fingerprint = initval; 283 } 284 fingerprint() const285 uint64_t fingerprint() const { 286 // Since reads aren't atomic for 64 bits, if any of the high or low order 287 // word is the initial value, return 0. See init_fingerprint for initval. 288 uint high_fp = (uint)(_fingerprint >> 32); 289 if ((int) _fingerprint == 0 || high_fp == 0x80000000) { 290 return 0L; 291 } else { 292 return _fingerprint; 293 } 294 } 295 set_fingerprint(uint64_t new_fingerprint)296 uint64_t set_fingerprint(uint64_t new_fingerprint) { 297 #ifdef ASSERT 298 // Assert only valid if complete/valid 64 bit _fingerprint value is read. 299 uint64_t oldfp = fingerprint(); 300 #endif // ASSERT 301 _fingerprint = new_fingerprint; 302 assert(oldfp == 0L || new_fingerprint == oldfp, 303 "fingerprint cannot change"); 304 assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0, 305 "fingerprint should call init to set initial value"); 306 return new_fingerprint; 307 } 308 309 // name name_index() const310 int name_index() const { return _name_index; } set_name_index(int index)311 void set_name_index(int index) { _name_index = index; } 312 313 // signature signature_index() const314 int signature_index() const { return _signature_index; } set_signature_index(int index)315 void set_signature_index(int index) { _signature_index = index; } 316 317 // generics support generic_signature_index() const318 int generic_signature_index() const { 319 if (has_generic_signature()) { 320 return *generic_signature_index_addr(); 321 } else { 322 return 0; 323 } 324 } set_generic_signature_index(u2 index)325 void set_generic_signature_index(u2 index) { 326 assert(has_generic_signature(), ""); 327 u2* addr = generic_signature_index_addr(); 328 *addr = index; 329 } 330 331 // Sizing header_size()332 static int header_size() { 333 return align_up((int)sizeof(ConstMethod), wordSize) / wordSize; 334 } 335 336 // Size needed 337 static int size(int code_size, InlineTableSizes* sizes); 338 size() const339 int size() const { return _constMethod_size;} set_constMethod_size(int size)340 void set_constMethod_size(int size) { _constMethod_size = size; } 341 342 // ConstMethods should be stored in the read-only region of CDS archive. is_read_only_by_default()343 static bool is_read_only_by_default() { return true; } 344 345 // code size code_size() const346 int code_size() const { return _code_size; } set_code_size(int size)347 void set_code_size(int size) { 348 assert(max_method_code_size < (1 << 16), 349 "u2 is too small to hold method code size in general"); 350 assert(0 <= size && size <= max_method_code_size, "invalid code size"); 351 _code_size = size; 352 } 353 354 // linenumber table - note that length is unknown until decompression, 355 // see class CompressedLineNumberReadStream. 356 u_char* compressed_linenumber_table() const; // not preserved by gc 357 u2* generic_signature_index_addr() const; 358 u2* checked_exceptions_length_addr() const; 359 u2* localvariable_table_length_addr() const; 360 u2* exception_table_length_addr() const; 361 u2* method_parameters_length_addr() const; 362 363 // checked exceptions 364 int checked_exceptions_length() const; 365 CheckedExceptionElement* checked_exceptions_start() const; 366 367 // localvariable table 368 int localvariable_table_length() const; 369 LocalVariableTableElement* localvariable_table_start() const; 370 371 // exception table 372 int exception_table_length() const; 373 ExceptionTableElement* exception_table_start() const; 374 375 // method parameters table 376 377 // This returns -1 if no parameters are present, a non-negative 378 // value otherwise. Note: sometimes, there are 0-length parameters 379 // attributes that must be reported up to the reflection API all the 380 // same. 381 int method_parameters_length() const; 382 MethodParametersElement* method_parameters_start() const; 383 384 // method annotations has_method_annotations() const385 bool has_method_annotations() const 386 { return (_flags & _has_method_annotations) != 0; } 387 has_parameter_annotations() const388 bool has_parameter_annotations() const 389 { return (_flags & _has_parameter_annotations) != 0; } 390 has_type_annotations() const391 bool has_type_annotations() const 392 { return (_flags & _has_type_annotations) != 0; } 393 has_default_annotations() const394 bool has_default_annotations() const 395 { return (_flags & _has_default_annotations) != 0; } 396 397 398 AnnotationArray** method_annotations_addr() const; method_annotations() const399 AnnotationArray* method_annotations() const { 400 return has_method_annotations() ? *(method_annotations_addr()) : NULL; 401 } set_method_annotations(AnnotationArray * anno)402 void set_method_annotations(AnnotationArray* anno) { 403 *(method_annotations_addr()) = anno; 404 } 405 406 AnnotationArray** parameter_annotations_addr() const; parameter_annotations() const407 AnnotationArray* parameter_annotations() const { 408 return has_parameter_annotations() ? *(parameter_annotations_addr()) : NULL; 409 } set_parameter_annotations(AnnotationArray * anno)410 void set_parameter_annotations(AnnotationArray* anno) { 411 *(parameter_annotations_addr()) = anno; 412 } 413 414 AnnotationArray** type_annotations_addr() const; type_annotations() const415 AnnotationArray* type_annotations() const { 416 return has_type_annotations() ? *(type_annotations_addr()) : NULL; 417 } set_type_annotations(AnnotationArray * anno)418 void set_type_annotations(AnnotationArray* anno) { 419 *(type_annotations_addr()) = anno; 420 } 421 422 AnnotationArray** default_annotations_addr() const; default_annotations() const423 AnnotationArray* default_annotations() const { 424 return has_default_annotations() ? *(default_annotations_addr()) : NULL; 425 } set_default_annotations(AnnotationArray * anno)426 void set_default_annotations(AnnotationArray* anno) { 427 *(default_annotations_addr()) = anno; 428 } 429 method_annotations_length() const430 int method_annotations_length() const { 431 return has_method_annotations() ? method_annotations()->length() : 0; 432 } parameter_annotations_length() const433 int parameter_annotations_length() const { 434 return has_parameter_annotations() ? parameter_annotations()->length() : 0; 435 } type_annotations_length() const436 int type_annotations_length() const { 437 return has_type_annotations() ? type_annotations()->length() : 0; 438 } default_annotations_length() const439 int default_annotations_length() const { 440 return has_default_annotations() ? default_annotations()->length() : 0; 441 } 442 443 // Copy annotations from other ConstMethod 444 void copy_annotations_from(ClassLoaderData* loader_data, ConstMethod* cm, TRAPS); 445 446 // byte codes set_code(address code)447 void set_code(address code) { 448 if (code_size() > 0) { 449 memcpy(code_base(), code, code_size()); 450 } 451 } code_base() const452 address code_base() const { return (address) (this+1); } code_end() const453 address code_end() const { return code_base() + code_size(); } contains(address bcp) const454 bool contains(address bcp) const { return code_base() <= bcp 455 && bcp < code_end(); } 456 // Offset to bytecodes codes_offset()457 static ByteSize codes_offset() 458 { return in_ByteSize(sizeof(ConstMethod)); } 459 constants_offset()460 static ByteSize constants_offset() 461 { return byte_offset_of(ConstMethod, _constants); } 462 max_stack_offset()463 static ByteSize max_stack_offset() 464 { return byte_offset_of(ConstMethod, _max_stack); } size_of_locals_offset()465 static ByteSize size_of_locals_offset() 466 { return byte_offset_of(ConstMethod, _max_locals); } size_of_parameters_offset()467 static ByteSize size_of_parameters_offset() 468 { return byte_offset_of(ConstMethod, _size_of_parameters); } 469 result_type_offset()470 static ByteSize result_type_offset() 471 { return byte_offset_of(ConstMethod, _result_type); } 472 473 // Unique id for the method 474 static const u2 MAX_IDNUM; 475 static const u2 UNSET_IDNUM; method_idnum() const476 u2 method_idnum() const { return _method_idnum; } set_method_idnum(u2 idnum)477 void set_method_idnum(u2 idnum) { _method_idnum = idnum; } 478 orig_method_idnum() const479 u2 orig_method_idnum() const { return _orig_method_idnum; } set_orig_method_idnum(u2 idnum)480 void set_orig_method_idnum(u2 idnum) { _orig_method_idnum = idnum; } 481 482 // max stack max_stack() const483 int max_stack() const { return _max_stack; } set_max_stack(int size)484 void set_max_stack(int size) { _max_stack = size; } 485 486 // max locals max_locals() const487 int max_locals() const { return _max_locals; } set_max_locals(int size)488 void set_max_locals(int size) { _max_locals = size; } 489 490 // size of parameters size_of_parameters() const491 int size_of_parameters() const { return _size_of_parameters; } set_size_of_parameters(int size)492 void set_size_of_parameters(int size) { _size_of_parameters = size; } 493 494 // result type (basic type of return value) result_type() const495 BasicType result_type() const { assert(_result_type >= T_BOOLEAN, "Must be set"); 496 return (BasicType)_result_type; } 497 set_result_type(BasicType rt)498 void set_result_type(BasicType rt) { assert(rt < 16, "result type too large"); 499 _result_type = (u1)rt; } 500 // Deallocation for RedefineClasses 501 void deallocate_contents(ClassLoaderData* loader_data); is_klass() const502 bool is_klass() const { return false; } 503 DEBUG_ONLY(bool on_stack() { return false; }) 504 505 void metaspace_pointers_do(MetaspaceClosure* it); type() const506 MetaspaceObj::Type type() const { return ConstMethodType; } 507 private: 508 // Since the size of the compressed line number table is unknown, the 509 // offsets of the other variable sized sections are computed backwards 510 // from the end of the ConstMethod*. 511 512 // First byte after ConstMethod* constMethod_end() const513 address constMethod_end() const 514 { return (address)((intptr_t*)this + _constMethod_size); } 515 516 // Last short in ConstMethod* 517 u2* last_u2_element() const; 518 519 public: 520 // Printing 521 void print_on (outputStream* st) const; 522 void print_value_on(outputStream* st) const; 523 internal_name() const524 const char* internal_name() const { return "{constMethod}"; } 525 526 // Verify 527 void verify_on(outputStream* st); 528 }; 529 530 #endif // SHARE_OOPS_CONSTMETHOD_HPP 531