1 /*
   2  * Copyright (c) 2003, 2012, 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_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
  31 // do not vary.
  32 //
  33 // Memory layout (each line represents a word). Note that most
  34 // applications load thousands of methods, so keeping the size of this
  35 // structure small has a big impact on footprint.
  36 //
  37 // |------------------------------------------------------|
  38 // | header                                               |
  39 // | klass                                                |
  40 // |------------------------------------------------------|
  41 // | fingerprint 1                                        |
  42 // | fingerprint 2                                        |
  43 // | constants                      (oop)                 |
  44 // | stackmap_data                  (oop)                 |
  45 // | constMethod_size                                     |
  46 // | interp_kind  | flags    | code_size                  |
  47 // | name index              | signature index            |
  48 // | method_idnum            | max_stack                  |
  49 // | max_locals              | size_of_parameters         |
  50 // |------------------------------------------------------|
  51 // |                                                      |
  52 // | byte codes                                           |
  53 // |                                                      |
  54 // |------------------------------------------------------|
  55 // | 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 // |------------------------------------------------------|
  62 // | 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 // |------------------------------------------------------|
  68 // | exception table + length (length last)               |
  69 // |  (length is u2, elements are 4-tuples of u2)         |
  70 // |  (see class ExceptionTableElement)                   |
  71 // |  (access flags bit tells whether table is present)   |
  72 // |  (indexed from end of ConstMethod*)                  |
  73 // |------------------------------------------------------|
  74 // | checked exceptions elements + length (length last)   |
  75 // |  (length is u2, elements are u2)                     |
  76 // |  (see class CheckedExceptionElement)                 |
  77 // |  (access flags bit tells whether table is present)   |
  78 // |  (indexed from end of ConstMethod*)                  |
  79 // |------------------------------------------------------|
  80 // | method parameters elements + length (length last)    |
  81 // |  (length is u2, elements are u2, u4 structures)      |
  82 // |  (see class MethodParametersElement)                 |
  83 // |  (access flags bit tells whether table is present)   |
  84 // |  (indexed from end of ConstMethod*)                  |
  85 // |------------------------------------------------------|
  86 // | generic signature index (u2)                         |
  87 // |  (indexed from start of constMethodOop)              |
  88 // |------------------------------------------------------|
  89 //
  90 // IMPORTANT: If anything gets added here, there need to be changes to
  91 // ensure that ServicabilityAgent doesn't get broken as a result!
  92 
  93 
  94 // Utitily class decribing elements in checked exceptions table inlined in Method*.
  95 class CheckedExceptionElement VALUE_OBJ_CLASS_SPEC {
  96  public:
  97   u2 class_cp_index;
  98 };
  99 
 100 
 101 // Utitily class decribing elements in local variable table inlined in Method*.
 102 class LocalVariableTableElement VALUE_OBJ_CLASS_SPEC {
 103  public:
 104   u2 start_bci;
 105   u2 length;
 106   u2 name_cp_index;
 107   u2 descriptor_cp_index;
 108   u2 signature_cp_index;
 109   u2 slot;
 110 };
 111 
 112 // Utitily class describing elements in exception table
 113 class ExceptionTableElement VALUE_OBJ_CLASS_SPEC {
 114  public:
 115   u2 start_pc;
 116   u2 end_pc;
 117   u2 handler_pc;
 118   u2 catch_type_index;
 119 };
 120 
 121 // Utility class describing elements in method parameters
 122 class MethodParametersElement VALUE_OBJ_CLASS_SPEC {
 123  public:
 124   u2 name_cp_index;
 125   // This has to happen, otherwise it will cause SIGBUS from a
 126   // misaligned u4 on some architectures (ie SPARC)
 127   // because MethodParametersElements are only aligned mod 2
 128   // within the ConstMethod container  u2 flags_hi;
 129   u2 flags_hi;
 130   u2 flags_lo;
 131 };
 132 
 133 
 134 class ConstMethod : public MetaspaceObj {
 135   friend class VMStructs;
 136 
 137 public:
 138   typedef enum { NORMAL, OVERPASS } MethodType;
 139 
 140 private:
 141   enum {
 142     _has_linenumber_table = 1,
 143     _has_checked_exceptions = 2,
 144     _has_localvariable_table = 4,
 145     _has_exception_table = 8,
 146     _has_generic_signature = 16,
 147     _has_method_parameters = 32,
 148     _is_overpass = 64
 149   };
 150 
 151   // Bit vector of signature
 152   // Callers interpret 0=not initialized yet and
 153   // -1=too many args to fix, must parse the slow way.
 154   // The real initial value is special to account for nonatomicity of 64 bit
 155   // loads and stores.  This value may updated and read without a lock by
 156   // multiple threads, so is volatile.
 157   volatile uint64_t _fingerprint;
 158 
 159   ConstantPool*     _constants;                  // Constant pool
 160 
 161   // Raw stackmap data for the method
 162   Array<u1>*        _stackmap_data;
 163 
 164   int               _constMethod_size;
 165   jbyte             _interpreter_kind;
 166   jbyte             _flags;
 167 
 168   // Size of Java bytecodes allocated immediately after Method*.
 169   u2                _code_size;
 170   u2                _name_index;                 // Method name (index in constant pool)
 171   u2                _signature_index;            // Method signature (index in constant pool)
 172   u2                _method_idnum;               // unique identification number for the method within the class
 173                                                  // initially corresponds to the index into the methods array.
 174                                                  // but this may change with redefinition
 175   u2                _max_stack;                  // Maximum number of entries on the expression stack
 176   u2                _max_locals;                 // Number of local variables used by this method
 177   u2                _size_of_parameters;         // size of the parameter block (receiver + arguments) in words
 178 
 179   // Constructor
 180   ConstMethod(int byte_code_size,
 181               int compressed_line_number_size,
 182               int localvariable_table_length,
 183               int exception_table_length,
 184               int checked_exceptions_length,
 185               int method_parameters_length,
 186               u2  generic_signature_index,
 187               MethodType is_overpass,
 188               int size);
 189 public:
 190 
 191   static ConstMethod* allocate(ClassLoaderData* loader_data,
 192                                int byte_code_size,
 193                                int compressed_line_number_size,
 194                                int localvariable_table_length,
 195                                int exception_table_length,
 196                                int checked_exceptions_length,
 197                                int method_parameters_length,
 198                                u2  generic_signature_index,
 199                                MethodType mt,
 200                                TRAPS);
 201 
 202   bool is_constMethod() const { return true; }
 203 
 204   // Inlined tables
 205   void set_inlined_tables_length(u2  generic_signature_index,
 206                                  int checked_exceptions_len,
 207                                  int compressed_line_number_size,
 208                                  int localvariable_table_len,
 209                                  int exception_table_len,
 210                                  int method_parameters_length);
 211 
 212   bool has_generic_signature() const
 213     { return (_flags & _has_generic_signature) != 0; }
 214 
 215   bool has_linenumber_table() const
 216     { return (_flags & _has_linenumber_table) != 0; }
 217 
 218   bool has_checked_exceptions() const
 219     { return (_flags & _has_checked_exceptions) != 0; }
 220 
 221   bool has_localvariable_table() const
 222     { return (_flags & _has_localvariable_table) != 0; }
 223 
 224   bool has_exception_handler() const
 225     { return (_flags & _has_exception_table) != 0; }
 226 
 227   bool has_method_parameters() const
 228     { return (_flags & _has_method_parameters) != 0; }
 229 
 230   MethodType method_type() const {
 231     return ((_flags & _is_overpass) == 0) ? NORMAL : OVERPASS;
 232   }
 233 
 234   void set_method_type(MethodType mt) {
 235     if (mt == NORMAL) {
 236       _flags &= ~(_is_overpass);
 237     } else {
 238       _flags |= _is_overpass;
 239     }
 240   }
 241 
 242 
 243   void set_interpreter_kind(int kind)      { _interpreter_kind = kind; }
 244   int  interpreter_kind(void) const        { return _interpreter_kind; }
 245 
 246   // constant pool
 247   ConstantPool* constants() const        { return _constants; }
 248   void set_constants(ConstantPool* c)    { _constants = c; }
 249 
 250   Method* method() const;
 251 
 252   // stackmap table data
 253   Array<u1>* stackmap_data() const { return _stackmap_data; }
 254   void set_stackmap_data(Array<u1>* sd) { _stackmap_data = sd; }
 255   bool has_stackmap_table() const { return _stackmap_data != NULL; }
 256 
 257   void init_fingerprint() {
 258     const uint64_t initval = CONST64(0x8000000000000000);
 259     _fingerprint = initval;
 260   }
 261 
 262   uint64_t fingerprint() const                   {
 263     // Since reads aren't atomic for 64 bits, if any of the high or low order
 264     // word is the initial value, return 0.  See init_fingerprint for initval.
 265     uint high_fp = (uint)(_fingerprint >> 32);
 266     if ((int) _fingerprint == 0 || high_fp == 0x80000000) {
 267       return 0L;
 268     } else {
 269       return _fingerprint;
 270     }
 271   }
 272 
 273   uint64_t set_fingerprint(uint64_t new_fingerprint) {
 274 #ifdef ASSERT
 275     // Assert only valid if complete/valid 64 bit _fingerprint value is read.
 276     uint64_t oldfp = fingerprint();
 277 #endif // ASSERT
 278     _fingerprint = new_fingerprint;
 279     assert(oldfp == 0L || new_fingerprint == oldfp,
 280            "fingerprint cannot change");
 281     assert(((new_fingerprint >> 32) != 0x80000000) && (int)new_fingerprint !=0,
 282            "fingerprint should call init to set initial value");
 283     return new_fingerprint;
 284   }
 285 
 286   // name
 287   int name_index() const                         { return _name_index; }
 288   void set_name_index(int index)                 { _name_index = index; }
 289 
 290   // signature
 291   int signature_index() const                    { return _signature_index; }
 292   void set_signature_index(int index)            { _signature_index = index; }
 293 
 294   // generics support
 295   int generic_signature_index() const            {
 296     if (has_generic_signature()) {
 297       return *generic_signature_index_addr();
 298     } else {
 299       return 0;
 300     }
 301   }
 302   void set_generic_signature_index(u2 index)    {
 303     assert(has_generic_signature(), "");
 304     u2* addr = generic_signature_index_addr();
 305     *addr = index;
 306   }
 307 
 308   // Sizing
 309   static int header_size() {
 310     return sizeof(ConstMethod)/HeapWordSize;
 311   }
 312 
 313   // Size needed
 314   static int size(int code_size, int compressed_line_number_size,
 315                   int local_variable_table_length,
 316                   int exception_table_length,
 317                   int checked_exceptions_length,
 318                   int method_parameters_length,
 319                   u2  generic_signature_index);
 320 
 321   int size() const                    { return _constMethod_size;}
 322   void set_constMethod_size(int size)     { _constMethod_size = size; }
 323 
 324   // code size
 325   int code_size() const                          { return _code_size; }
 326   void set_code_size(int size) {
 327     assert(max_method_code_size < (1 << 16),
 328            "u2 is too small to hold method code size in general");
 329     assert(0 <= size && size <= max_method_code_size, "invalid code size");
 330     _code_size = size;
 331   }
 332 
 333   // linenumber table - note that length is unknown until decompression,
 334   // see class CompressedLineNumberReadStream.
 335   u_char* compressed_linenumber_table() const;         // not preserved by gc
 336   u2* generic_signature_index_addr() const;
 337   u2* checked_exceptions_length_addr() const;
 338   u2* localvariable_table_length_addr() const;
 339   u2* exception_table_length_addr() const;
 340   u2* method_parameters_length_addr() const;
 341 
 342   // checked exceptions
 343   int checked_exceptions_length() const;
 344   CheckedExceptionElement* checked_exceptions_start() const;
 345 
 346   // localvariable table
 347   int localvariable_table_length() const;
 348   LocalVariableTableElement* localvariable_table_start() const;
 349 
 350   // exception table
 351   int exception_table_length() const;
 352   ExceptionTableElement* exception_table_start() const;
 353 
 354   // method parameters table
 355   int method_parameters_length() const;
 356   MethodParametersElement* method_parameters_start() const;
 357 
 358   // byte codes
 359   void    set_code(address code) {
 360     if (code_size() > 0) {
 361       memcpy(code_base(), code, code_size());
 362     }
 363   }
 364   address code_base() const            { return (address) (this+1); }
 365   address code_end() const             { return code_base() + code_size(); }
 366   bool    contains(address bcp) const  { return code_base() <= bcp
 367                                                      && bcp < code_end(); }
 368   // Offset to bytecodes
 369   static ByteSize codes_offset()
 370                             { return in_ByteSize(sizeof(ConstMethod)); }
 371 
 372   static ByteSize constants_offset()
 373                             { return byte_offset_of(ConstMethod, _constants); }
 374 
 375   static ByteSize max_stack_offset()
 376                             { return byte_offset_of(ConstMethod, _max_stack); }
 377   static ByteSize size_of_locals_offset()
 378                             { return byte_offset_of(ConstMethod, _max_locals); }
 379   static ByteSize size_of_parameters_offset()
 380                             { return byte_offset_of(ConstMethod, _size_of_parameters); }
 381 
 382 
 383   // Unique id for the method
 384   static const u2 MAX_IDNUM;
 385   static const u2 UNSET_IDNUM;
 386   u2 method_idnum() const                        { return _method_idnum; }
 387   void set_method_idnum(u2 idnum)                { _method_idnum = idnum; }
 388 
 389   // max stack
 390   int  max_stack() const                         { return _max_stack; }
 391   void set_max_stack(int size)                   { _max_stack = size; }
 392 
 393   // max locals
 394   int  max_locals() const                        { return _max_locals; }
 395   void set_max_locals(int size)                  { _max_locals = size; }
 396 
 397   // size of parameters
 398   int  size_of_parameters() const                { return _size_of_parameters; }
 399   void set_size_of_parameters(int size)          { _size_of_parameters = size; }
 400 
 401   // Deallocation for RedefineClasses
 402   void deallocate_contents(ClassLoaderData* loader_data);
 403   bool is_klass() const { return false; }
 404   DEBUG_ONLY(bool on_stack() { return false; })
 405 
 406 private:
 407   // Since the size of the compressed line number table is unknown, the
 408   // offsets of the other variable sized sections are computed backwards
 409   // from the end of the ConstMethod*.
 410 
 411   // First byte after ConstMethod*
 412   address constMethod_end() const
 413                           { return (address)((oop*)this + _constMethod_size); }
 414 
 415   // Last short in ConstMethod*
 416   u2* last_u2_element() const
 417                                          { return (u2*)constMethod_end() - 1; }
 418 
 419  public:
 420   // Printing
 421   void print_on      (outputStream* st) const;
 422   void print_value_on(outputStream* st) const;
 423 
 424   const char* internal_name() const { return "{constMethod}"; }
 425 
 426   // Verify
 427   void verify_on(outputStream* st);
 428 };
 429 
 430 #endif // SHARE_VM_OOPS_CONSTMETHODOOP_HPP