1 /*
   2  * Copyright (c) 2003, 2014, 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  *
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  24 
  25 #ifndef SHARE_VM_OOPS_CONSTMETHODOOP_HPP
  26 #define SHARE_VM_OOPS_CONSTMETHODOOP_HPP
  27 
  28 #include "oops/oop.hpp"
  29 
  30 // An ConstMethod represents portions of a Java method which are not written to after
  31 // the classfile is parsed(*see below).  This part of the method can be shared across
  32 // processes in a read-only section with Class Data Sharing (CDS).  It's important
  33 // that this class doesn't have virtual functions because the vptr cannot be shared
  34 // with CDS.
  35 //   (*)RewriteByteCodes and RewriteFrequentPairs is an exception but turned off in 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 VALUE_OBJ_CLASS_SPEC {
  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 VALUE_OBJ_CLASS_SPEC {
  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 VALUE_OBJ_CLASS_SPEC {
 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 VALUE_OBJ_CLASS_SPEC {
 119  public:
 120   u2 name_cp_index;
 121   u2 flags;
 122 };
 123 
 124 class KlassSizeStats;
 125 
 126 // Class to collect the sizes of ConstMethod inline tables
 127 #define INLINE_TABLES_DO(do_element)            \
 128   do_element(localvariable_table_length)        \
 129   do_element(compressed_linenumber_size)        \
 130   do_element(exception_table_length)            \
 131   do_element(checked_exceptions_length)         \
 132   do_element(method_parameters_length)          \
 133   do_element(generic_signature_index)           \
 134   do_element(method_annotations_length)         \
 135   do_element(parameter_annotations_length)      \
 136   do_element(type_annotations_length)           \
 137   do_element(default_annotations_length)
 138 
 139 #define INLINE_TABLE_DECLARE(sym)    int _##sym;
 140 #define INLINE_TABLE_PARAM(sym)      int sym,
 141 #define INLINE_TABLE_INIT(sym)       _##sym(sym),
 142 #define INLINE_TABLE_NULL(sym)       _##sym(0),
 143 #define INLINE_TABLE_ACCESSOR(sym)   int sym() const { return _##sym; }
 144 
 145 class InlineTableSizes : StackObj {
 146   // declarations
 147   INLINE_TABLES_DO(INLINE_TABLE_DECLARE)
 148   int _end;
 149  public:
 150   InlineTableSizes(
 151       INLINE_TABLES_DO(INLINE_TABLE_PARAM)
 152       int end) :
 153       INLINE_TABLES_DO(INLINE_TABLE_INIT)
 154       _end(end) {}
 155 
 156   // Default constructor for no inlined tables
 157   InlineTableSizes() :
 158       INLINE_TABLES_DO(INLINE_TABLE_NULL)
 159       _end(0) {}
 160 
 161   // Accessors
 162   INLINE_TABLES_DO(INLINE_TABLE_ACCESSOR)
 163 };
 164 #undef INLINE_TABLE_ACCESSOR
 165 #undef INLINE_TABLE_NULL
 166 #undef INLINE_TABLE_INIT
 167 #undef INLINE_TABLE_PARAM
 168 #undef INLINE_TABLE_DECLARE
 169 
 170 
 171 class ConstMethod : public MetaspaceObj {
 172   friend class VMStructs;
 173 
 174 public:
 175   typedef enum { NORMAL, OVERPASS } MethodType;
 176 
 177 private:
 178   enum {
 179     _has_linenumber_table = 0x0001,
 180     _has_checked_exceptions = 0x0002,
 181     _has_localvariable_table = 0x0004,
 182     _has_exception_table = 0x0008,
 183     _has_generic_signature = 0x0010,
 184     _has_method_parameters = 0x0020,
 185     _is_overpass = 0x0040,
 186     _has_method_annotations = 0x0080,
 187     _has_parameter_annotations = 0x0100,
 188     _has_type_annotations = 0x0200,
 189     _has_default_annotations = 0x0400
 190   };
 191 
 192   // Bit vector of signature
 193   // Callers interpret 0=not initialized yet and
 194   // -1=too many args to fix, must parse the slow way.
 195   // The real initial value is special to account for nonatomicity of 64 bit
 196   // loads and stores.  This value may updated and read without a lock by
 197   // multiple threads, so is volatile.
 198   volatile uint64_t _fingerprint;
 199 
 200   ConstantPool*     _constants;                  // Constant pool
 201 
 202   // Raw stackmap data for the method
 203   Array<u1>*        _stackmap_data;
 204 
 205   int               _constMethod_size;
 206   u2                _flags;
 207 
 208   // Size of Java bytecodes allocated immediately after Method*.
 209   u2                _code_size;
 210   u2                _name_index;                 // Method name (index in constant pool)
 211   u2                _signature_index;            // Method signature (index in constant pool)
 212   u2                _method_idnum;               // unique identification number for the method within the class
 213                                                  // initially corresponds to the index into the methods array.
 214                                                  // but this may change with redefinition
 215   u2                _max_stack;                  // Maximum number of entries on the expression stack
 216   u2                _max_locals;                 // Number of local variables used by this method
 217   u2                _size_of_parameters;         // size of the parameter block (receiver + arguments) in words
 218   u2                _orig_method_idnum;          // Original unique identification number for the method
 219 
 220   // Constructor
 221   ConstMethod(int byte_code_size,
 222               InlineTableSizes* sizes,
 223               MethodType is_overpass,
 224               int size);
 225 public:
 226 
 227   static ConstMethod* allocate(ClassLoaderData* loader_data,
 228                                int byte_code_size,
 229                                InlineTableSizes* sizes,
 230                                MethodType mt,
 231                                TRAPS);
 232 
 233   bool is_constMethod() const { return true; }
 234 
 235   // Inlined tables
 236   void set_inlined_tables_length(InlineTableSizes* sizes);
 237 
 238   bool has_generic_signature() const
 239     { return (_flags & _has_generic_signature) != 0; }
 240 
 241   bool has_linenumber_table() const
 242     { return (_flags & _has_linenumber_table) != 0; }
 243 
 244   bool has_checked_exceptions() const
 245     { return (_flags & _has_checked_exceptions) != 0; }
 246 
 247   bool has_localvariable_table() const
 248     { return (_flags & _has_localvariable_table) != 0; }
 249 
 250   bool has_exception_handler() const
 251     { return (_flags & _has_exception_table) != 0; }
 252 
 253   bool has_method_parameters() const
 254     { return (_flags & _has_method_parameters) != 0; }
 255 
 256   MethodType method_type() const {
 257     return ((_flags & _is_overpass) == 0) ? NORMAL : OVERPASS;
 258   }
 259 
 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
 269   ConstantPool* constants() const        { return _constants; }
 270   void set_constants(ConstantPool* c)    { _constants = c; }
 271 
 272   Method* method() const;
 273 
 274   // stackmap table data
 275   Array<u1>* stackmap_data() const { return _stackmap_data; }
 276   void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; }
 277   void copy_stackmap_data(ClassLoaderData* loader_data, u1* sd, int length, TRAPS);
 278   bool has_stackmap_table() const { return _stackmap_data != NULL; }
 279 
 280   void init_fingerprint() {
 281     const uint64_t initval = UCONST64(0x8000000000000000);
 282     _fingerprint = initval;
 283   }
 284 
 285   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 
 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
 310   int name_index() const                         { return _name_index; }
 311   void set_name_index(int index)                 { _name_index = index; }
 312 
 313   // signature
 314   int signature_index() const                    { return _signature_index; }
 315   void set_signature_index(int index)            { _signature_index = index; }
 316 
 317   // generics support
 318   int generic_signature_index() const            {
 319     if (has_generic_signature()) {
 320       return *generic_signature_index_addr();
 321     } else {
 322       return 0;
 323     }
 324   }
 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
 332   static int header_size() {
 333     return sizeof(ConstMethod)/HeapWordSize;
 334   }
 335 
 336   // Size needed
 337   static int size(int code_size, InlineTableSizes* sizes);
 338 
 339   int size() const                    { return _constMethod_size;}
 340   void set_constMethod_size(int size)     { _constMethod_size = size; }
 341 #if INCLUDE_SERVICES
 342   void collect_statistics(KlassSizeStats *sz) const;
 343 #endif
 344 
 345   // code size
 346   int code_size() const                          { return _code_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
 385   bool has_method_annotations() const
 386     { return (_flags & _has_method_annotations) != 0; }
 387 
 388   bool has_parameter_annotations() const
 389     { return (_flags & _has_parameter_annotations) != 0; }
 390 
 391   bool has_type_annotations() const
 392     { return (_flags & _has_type_annotations) != 0; }
 393 
 394   bool has_default_annotations() const
 395     { return (_flags & _has_default_annotations) != 0; }
 396 
 397 
 398   AnnotationArray** method_annotations_addr() const;
 399   AnnotationArray* method_annotations() const  {
 400     return has_method_annotations() ? *(method_annotations_addr()) : NULL;
 401   }
 402   void set_method_annotations(AnnotationArray* anno) {
 403     *(method_annotations_addr()) = anno;
 404   }
 405 
 406   AnnotationArray** parameter_annotations_addr() const;
 407   AnnotationArray* parameter_annotations() const {
 408     return has_parameter_annotations() ? *(parameter_annotations_addr()) : NULL;
 409   }
 410   void set_parameter_annotations(AnnotationArray* anno) {
 411     *(parameter_annotations_addr()) = anno;
 412   }
 413 
 414   AnnotationArray** type_annotations_addr() const;
 415   AnnotationArray* type_annotations() const {
 416     return has_type_annotations() ? *(type_annotations_addr()) : NULL;
 417   }
 418   void set_type_annotations(AnnotationArray* anno) {
 419     *(type_annotations_addr()) = anno;
 420   }
 421 
 422   AnnotationArray** default_annotations_addr() const;
 423   AnnotationArray* default_annotations() const {
 424     return has_default_annotations() ? *(default_annotations_addr()) : NULL;
 425   }
 426   void set_default_annotations(AnnotationArray* anno) {
 427     *(default_annotations_addr()) = anno;
 428   }
 429 
 430   int method_annotations_length() const {
 431     return has_method_annotations() ? method_annotations()->length() : 0;
 432   }
 433   int parameter_annotations_length() const {
 434     return has_parameter_annotations() ? parameter_annotations()->length() : 0;
 435   }
 436   int type_annotations_length() const {
 437     return has_type_annotations() ? type_annotations()->length() : 0;
 438   }
 439   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(ConstMethod* cm);
 445 
 446   // byte codes
 447   void    set_code(address code) {
 448     if (code_size() > 0) {
 449       memcpy(code_base(), code, code_size());
 450     }
 451   }
 452   address code_base() const            { return (address) (this+1); }
 453   address code_end() const             { return code_base() + code_size(); }
 454   bool    contains(address bcp) const  { return code_base() <= bcp
 455                                                      && bcp < code_end(); }
 456   // Offset to bytecodes
 457   static ByteSize codes_offset()
 458                             { return in_ByteSize(sizeof(ConstMethod)); }
 459 
 460   static ByteSize constants_offset()
 461                             { return byte_offset_of(ConstMethod, _constants); }
 462 
 463   static ByteSize max_stack_offset()
 464                             { return byte_offset_of(ConstMethod, _max_stack); }
 465   static ByteSize size_of_locals_offset()
 466                             { return byte_offset_of(ConstMethod, _max_locals); }
 467   static ByteSize size_of_parameters_offset()
 468                             { return byte_offset_of(ConstMethod, _size_of_parameters); }
 469 
 470 
 471   // Unique id for the method
 472   static const u2 MAX_IDNUM;
 473   static const u2 UNSET_IDNUM;
 474   u2 method_idnum() const                        { return _method_idnum; }
 475   void set_method_idnum(u2 idnum)                { _method_idnum = idnum; }
 476 
 477   u2 orig_method_idnum() const                   { return _orig_method_idnum; }
 478   void set_orig_method_idnum(u2 idnum)           { _orig_method_idnum = idnum; }
 479 
 480   // max stack
 481   int  max_stack() const                         { return _max_stack; }
 482   void set_max_stack(int size)                   { _max_stack = size; }
 483 
 484   // max locals
 485   int  max_locals() const                        { return _max_locals; }
 486   void set_max_locals(int size)                  { _max_locals = size; }
 487 
 488   // size of parameters
 489   int  size_of_parameters() const                { return _size_of_parameters; }
 490   void set_size_of_parameters(int size)          { _size_of_parameters = size; }
 491 
 492   // Deallocation for RedefineClasses
 493   void deallocate_contents(ClassLoaderData* loader_data);
 494   bool is_klass() const { return false; }
 495   DEBUG_ONLY(bool on_stack() { return false; })
 496 
 497 private:
 498   // Since the size of the compressed line number table is unknown, the
 499   // offsets of the other variable sized sections are computed backwards
 500   // from the end of the ConstMethod*.
 501 
 502   // First byte after ConstMethod*
 503   address constMethod_end() const
 504                           { return (address)((intptr_t*)this + _constMethod_size); }
 505 
 506   // Last short in ConstMethod*
 507   u2* last_u2_element() const;
 508 
 509  public:
 510   // Printing
 511   void print_on      (outputStream* st) const;
 512   void print_value_on(outputStream* st) const;
 513 
 514   const char* internal_name() const { return "{constMethod}"; }
 515 
 516   // Verify
 517   void verify_on(outputStream* st);
 518 };
 519 
 520 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP