1 /*
   2  * Copyright (c) 1997, 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.
  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_METHOD_HPP
  26 #define SHARE_OOPS_METHOD_HPP
  27 
  28 #include "classfile/vmSymbols.hpp"
  29 #include "code/compressedStream.hpp"
  30 #include "compiler/compilerDefinitions.hpp"
  31 #include "compiler/oopMap.hpp"
  32 #include "interpreter/invocationCounter.hpp"
  33 #include "oops/annotations.hpp"
  34 #include "oops/constantPool.hpp"
  35 #include "oops/methodCounters.hpp"
  36 #include "oops/instanceKlass.hpp"
  37 #include "oops/oop.hpp"
  38 #include "oops/typeArrayOop.hpp"
  39 #include "utilities/accessFlags.hpp"
  40 #include "utilities/align.hpp"
  41 #include "utilities/growableArray.hpp"
  42 #include "utilities/macros.hpp"
  43 #if INCLUDE_JFR
  44 #include "jfr/support/jfrTraceIdExtension.hpp"
  45 #endif
  46 
  47 
  48 // A Method represents a Java method.
  49 //
  50 // Note that most applications load thousands of methods, so keeping the size of this
  51 // class small has a big impact on footprint.
  52 //
  53 // Note that native_function and signature_handler have to be at fixed offsets
  54 // (required by the interpreter)
  55 //
  56 //  Method embedded field layout (after declared fields):
  57 //   [EMBEDDED native_function       (present only if native) ]
  58 //   [EMBEDDED signature_handler     (present only if native) ]
  59 
  60 class CheckedExceptionElement;
  61 class LocalVariableTableElement;
  62 class AdapterHandlerEntry;
  63 class MethodData;
  64 class MethodCounters;
  65 class ConstMethod;
  66 class InlineTableSizes;
  67 class KlassSizeStats;
  68 class CompiledMethod;
  69 class InterpreterOopMap;
  70 
  71 class Method : public Metadata {
  72  friend class VMStructs;
  73  friend class JVMCIVMStructs;
  74  private:
  75   // If you add a new field that points to any metaspace object, you
  76   // must add this field to Method::metaspace_pointers_do().
  77   ConstMethod*      _constMethod;                // Method read-only data.
  78   MethodData*       _method_data;
  79   MethodCounters*   _method_counters;
  80   AccessFlags       _access_flags;               // Access flags
  81   int               _vtable_index;               // vtable index of this method (see VtableIndexFlag)
  82                                                  // note: can have vtables with >2**16 elements (because of inheritance)
  83   u2                _intrinsic_id;               // vmSymbols::intrinsic_id (0 == _none)
  84 
  85   // Flags
  86   enum Flags {
  87     _caller_sensitive      = 1 << 0,
  88     _force_inline          = 1 << 1,
  89     _dont_inline           = 1 << 2,
  90     _hidden                = 1 << 3,
  91     _has_injected_profile  = 1 << 4,
  92     _running_emcp          = 1 << 5,
  93     _intrinsic_candidate   = 1 << 6,
  94     _reserved_stack_access = 1 << 7
  95   };
  96   mutable u2 _flags;
  97 
  98   JFR_ONLY(DEFINE_TRACE_FLAG;)
  99 
 100 #ifndef PRODUCT
 101   int               _compiled_invocation_count;  // Number of nmethod invocations so far (for perf. debugging)
 102 #endif
 103   // Entry point for calling both from and to the interpreter.
 104   address _i2i_entry;           // All-args-on-stack calling convention
 105   // Entry point for calling from compiled code, to compiled code if it exists
 106   // or else the interpreter.
 107   volatile address _from_compiled_entry;        // Cache of: _code ? _code->entry_point() : _adapter->c2i_entry()
 108   // The entry point for calling both from and to compiled code is
 109   // "_code->entry_point()".  Because of tiered compilation and de-opt, this
 110   // field can come and go.  It can transition from NULL to not-null at any
 111   // time (whenever a compile completes).  It can transition from not-null to
 112   // NULL only at safepoints (because of a de-opt).
 113   CompiledMethod* volatile _code;                       // Points to the corresponding piece of native code
 114   volatile address           _from_interpreted_entry; // Cache of _code ? _adapter->i2c_entry() : _i2i_entry
 115 
 116 #if INCLUDE_AOT && defined(TIERED)
 117   CompiledMethod* _aot_code;
 118 #endif
 119 
 120   // Constructor
 121   Method(ConstMethod* xconst, AccessFlags access_flags);
 122  public:
 123 
 124   static Method* allocate(ClassLoaderData* loader_data,
 125                           int byte_code_size,
 126                           AccessFlags access_flags,
 127                           InlineTableSizes* sizes,
 128                           ConstMethod::MethodType method_type,
 129                           TRAPS);
 130 
 131   // CDS and vtbl checking can create an empty Method to get vtbl pointer.
 132   Method(){}
 133 
 134   bool is_method() const volatile { return true; }
 135 
 136   void restore_unshareable_info(TRAPS);
 137 
 138   // accessors for instance variables
 139 
 140   ConstMethod* constMethod() const             { return _constMethod; }
 141   void set_constMethod(ConstMethod* xconst)    { _constMethod = xconst; }
 142 
 143 
 144   static address make_adapters(const methodHandle& mh, TRAPS);
 145   address from_compiled_entry() const;
 146   address from_compiled_entry_no_trampoline() const;
 147   address from_interpreted_entry() const;
 148 
 149   // access flag
 150   AccessFlags access_flags() const               { return _access_flags;  }
 151   void set_access_flags(AccessFlags flags)       { _access_flags = flags; }
 152 
 153   // name
 154   Symbol* name() const                           { return constants()->symbol_at(name_index()); }
 155   int name_index() const                         { return constMethod()->name_index();         }
 156   void set_name_index(int index)                 { constMethod()->set_name_index(index);       }
 157 
 158   // signature
 159   Symbol* signature() const                      { return constants()->symbol_at(signature_index()); }
 160   int signature_index() const                    { return constMethod()->signature_index();         }
 161   void set_signature_index(int index)            { constMethod()->set_signature_index(index);       }
 162 
 163   // generics support
 164   Symbol* generic_signature() const              { int idx = generic_signature_index(); return ((idx != 0) ? constants()->symbol_at(idx) : (Symbol*)NULL); }
 165   int generic_signature_index() const            { return constMethod()->generic_signature_index(); }
 166   void set_generic_signature_index(int index)    { constMethod()->set_generic_signature_index(index); }
 167 
 168   // annotations support
 169   AnnotationArray* annotations() const           {
 170     return constMethod()->method_annotations();
 171   }
 172   AnnotationArray* parameter_annotations() const {
 173     return constMethod()->parameter_annotations();
 174   }
 175   AnnotationArray* annotation_default() const    {
 176     return constMethod()->default_annotations();
 177   }
 178   AnnotationArray* type_annotations() const      {
 179     return constMethod()->type_annotations();
 180   }
 181 
 182   // Helper routine: get klass name + "." + method name + signature as
 183   // C string, for the purpose of providing more useful
 184   // fatal error handling. The string is allocated in resource
 185   // area if a buffer is not provided by the caller.
 186   char* name_and_sig_as_C_string() const;
 187   char* name_and_sig_as_C_string(char* buf, int size) const;
 188 
 189   // Static routine in the situations we don't have a Method*
 190   static char* name_and_sig_as_C_string(Klass* klass, Symbol* method_name, Symbol* signature);
 191   static char* name_and_sig_as_C_string(Klass* klass, Symbol* method_name, Symbol* signature, char* buf, int size);
 192 
 193   // Get return type + klass name + "." + method name + ( parameters types )
 194   // as a C string or print it to an outputStream.
 195   // This is to be used to assemble strings passed to Java, so that
 196   // the text more resembles Java code. Used in exception messages.
 197   // Memory is allocated in the resource area; the caller needs
 198   // a ResourceMark.
 199   const char* external_name() const;
 200   void  print_external_name(outputStream *os) const;
 201 
 202   static const char* external_name(                  Klass* klass, Symbol* method_name, Symbol* signature);
 203   static void  print_external_name(outputStream *os, Klass* klass, Symbol* method_name, Symbol* signature);
 204 
 205   Bytecodes::Code java_code_at(int bci) const {
 206     return Bytecodes::java_code_at(this, bcp_from(bci));
 207   }
 208   Bytecodes::Code code_at(int bci) const {
 209     return Bytecodes::code_at(this, bcp_from(bci));
 210   }
 211 
 212   // JVMTI breakpoints
 213 #if !INCLUDE_JVMTI
 214   Bytecodes::Code orig_bytecode_at(int bci) const {
 215     ShouldNotReachHere();
 216     return Bytecodes::_shouldnotreachhere;
 217   }
 218   void set_orig_bytecode_at(int bci, Bytecodes::Code code) {
 219     ShouldNotReachHere();
 220   };
 221   u2   number_of_breakpoints() const {return 0;}
 222 #else // !INCLUDE_JVMTI
 223   Bytecodes::Code orig_bytecode_at(int bci) const;
 224   void set_orig_bytecode_at(int bci, Bytecodes::Code code);
 225   void set_breakpoint(int bci);
 226   void clear_breakpoint(int bci);
 227   void clear_all_breakpoints();
 228   // Tracking number of breakpoints, for fullspeed debugging.
 229   // Only mutated by VM thread.
 230   u2   number_of_breakpoints()             const {
 231     MethodCounters* mcs = method_counters();
 232     if (mcs == NULL) {
 233       return 0;
 234     } else {
 235       return mcs->number_of_breakpoints();
 236     }
 237   }
 238   void incr_number_of_breakpoints(TRAPS)         {
 239     MethodCounters* mcs = get_method_counters(CHECK);
 240     if (mcs != NULL) {
 241       mcs->incr_number_of_breakpoints();
 242     }
 243   }
 244   void decr_number_of_breakpoints(TRAPS)         {
 245     MethodCounters* mcs = get_method_counters(CHECK);
 246     if (mcs != NULL) {
 247       mcs->decr_number_of_breakpoints();
 248     }
 249   }
 250   // Initialization only
 251   void clear_number_of_breakpoints()             {
 252     MethodCounters* mcs = method_counters();
 253     if (mcs != NULL) {
 254       mcs->clear_number_of_breakpoints();
 255     }
 256   }
 257 #endif // !INCLUDE_JVMTI
 258 
 259   // index into InstanceKlass methods() array
 260   // note: also used by jfr
 261   u2 method_idnum() const           { return constMethod()->method_idnum(); }
 262   void set_method_idnum(u2 idnum)   { constMethod()->set_method_idnum(idnum); }
 263 
 264   u2 orig_method_idnum() const           { return constMethod()->orig_method_idnum(); }
 265   void set_orig_method_idnum(u2 idnum)   { constMethod()->set_orig_method_idnum(idnum); }
 266 
 267   // code size
 268   int code_size() const                  { return constMethod()->code_size(); }
 269 
 270   // method size in words
 271   int method_size() const                { return sizeof(Method)/wordSize + ( is_native() ? 2 : 0 ); }
 272 
 273   // constant pool for Klass* holding this method
 274   ConstantPool* constants() const              { return constMethod()->constants(); }
 275   void set_constants(ConstantPool* c)          { constMethod()->set_constants(c); }
 276 
 277   // max stack
 278   // return original max stack size for method verification
 279   int  verifier_max_stack() const                { return constMethod()->max_stack(); }
 280   int           max_stack() const                { return constMethod()->max_stack() + extra_stack_entries(); }
 281   void      set_max_stack(int size)              {        constMethod()->set_max_stack(size); }
 282 
 283   // max locals
 284   int  max_locals() const                        { return constMethod()->max_locals(); }
 285   void set_max_locals(int size)                  { constMethod()->set_max_locals(size); }
 286 
 287   int highest_comp_level() const;
 288   void set_highest_comp_level(int level);
 289   int highest_osr_comp_level() const;
 290   void set_highest_osr_comp_level(int level);
 291 
 292 #if COMPILER2_OR_JVMCI
 293   // Count of times method was exited via exception while interpreting
 294   void interpreter_throwout_increment(TRAPS) {
 295     MethodCounters* mcs = get_method_counters(CHECK);
 296     if (mcs != NULL) {
 297       mcs->interpreter_throwout_increment();
 298     }
 299   }
 300 #endif
 301 
 302   int  interpreter_throwout_count() const        {
 303     MethodCounters* mcs = method_counters();
 304     if (mcs == NULL) {
 305       return 0;
 306     } else {
 307       return mcs->interpreter_throwout_count();
 308     }
 309   }
 310 
 311   // size of parameters
 312   int  size_of_parameters() const                { return constMethod()->size_of_parameters(); }
 313   void set_size_of_parameters(int size)          { constMethod()->set_size_of_parameters(size); }
 314 
 315   bool has_stackmap_table() const {
 316     return constMethod()->has_stackmap_table();
 317   }
 318 
 319   Array<u1>* stackmap_data() const {
 320     return constMethod()->stackmap_data();
 321   }
 322 
 323   void set_stackmap_data(Array<u1>* sd) {
 324     constMethod()->set_stackmap_data(sd);
 325   }
 326 
 327   // exception handler table
 328   bool has_exception_handler() const
 329                              { return constMethod()->has_exception_handler(); }
 330   int exception_table_length() const
 331                              { return constMethod()->exception_table_length(); }
 332   ExceptionTableElement* exception_table_start() const
 333                              { return constMethod()->exception_table_start(); }
 334 
 335   // Finds the first entry point bci of an exception handler for an
 336   // exception of klass ex_klass thrown at throw_bci. A value of NULL
 337   // for ex_klass indicates that the exception klass is not known; in
 338   // this case it matches any constraint class. Returns -1 if the
 339   // exception cannot be handled in this method. The handler
 340   // constraint classes are loaded if necessary. Note that this may
 341   // throw an exception if loading of the constraint classes causes
 342   // an IllegalAccessError (bugid 4307310) or an OutOfMemoryError.
 343   // If an exception is thrown, returns the bci of the
 344   // exception handler which caused the exception to be thrown, which
 345   // is needed for proper retries. See, for example,
 346   // InterpreterRuntime::exception_handler_for_exception.
 347   static int fast_exception_handler_bci_for(const methodHandle& mh, Klass* ex_klass, int throw_bci, TRAPS);
 348 
 349   // method data access
 350   MethodData* method_data() const              {
 351     return _method_data;
 352   }
 353 
 354   void set_method_data(MethodData* data);
 355 
 356   MethodCounters* method_counters() const {
 357     return _method_counters;
 358   }
 359 
 360   void clear_method_counters() {
 361     _method_counters = NULL;
 362   }
 363 
 364   bool init_method_counters(MethodCounters* counters);
 365 
 366 #ifdef TIERED
 367   // We are reusing interpreter_invocation_count as a holder for the previous event count!
 368   // We can do that since interpreter_invocation_count is not used in tiered.
 369   int prev_event_count() const                   {
 370     if (method_counters() == NULL) {
 371       return 0;
 372     } else {
 373       return method_counters()->interpreter_invocation_count();
 374     }
 375   }
 376   void set_prev_event_count(int count) {
 377     MethodCounters* mcs = method_counters();
 378     if (mcs != NULL) {
 379       mcs->set_interpreter_invocation_count(count);
 380     }
 381   }
 382   jlong prev_time() const                        {
 383     MethodCounters* mcs = method_counters();
 384     return mcs == NULL ? 0 : mcs->prev_time();
 385   }
 386   void set_prev_time(jlong time) {
 387     MethodCounters* mcs = method_counters();
 388     if (mcs != NULL) {
 389       mcs->set_prev_time(time);
 390     }
 391   }
 392   float rate() const                             {
 393     MethodCounters* mcs = method_counters();
 394     return mcs == NULL ? 0 : mcs->rate();
 395   }
 396   void set_rate(float rate) {
 397     MethodCounters* mcs = method_counters();
 398     if (mcs != NULL) {
 399       mcs->set_rate(rate);
 400     }
 401   }
 402 
 403 #if INCLUDE_AOT
 404   void set_aot_code(CompiledMethod* aot_code) {
 405     _aot_code = aot_code;
 406   }
 407 
 408   CompiledMethod* aot_code() const {
 409     return _aot_code;
 410   }
 411 #else
 412   CompiledMethod* aot_code() const { return NULL; }
 413 #endif // INCLUDE_AOT
 414 #endif // TIERED
 415 
 416   int nmethod_age() const {
 417     if (method_counters() == NULL) {
 418       return INT_MAX;
 419     } else {
 420       return method_counters()->nmethod_age();
 421     }
 422   }
 423 
 424   int invocation_count();
 425   int backedge_count();
 426 
 427   bool was_executed_more_than(int n);
 428   bool was_never_executed()                      { return !was_executed_more_than(0); }
 429 
 430   static void build_interpreter_method_data(const methodHandle& method, TRAPS);
 431 
 432   static MethodCounters* build_method_counters(Method* m, TRAPS);
 433 
 434   int interpreter_invocation_count() {
 435     if (TieredCompilation) {
 436       return invocation_count();
 437     } else {
 438       MethodCounters* mcs = method_counters();
 439       return (mcs == NULL) ? 0 : mcs->interpreter_invocation_count();
 440     }
 441   }
 442 #if COMPILER2_OR_JVMCI
 443   int increment_interpreter_invocation_count(TRAPS) {
 444     if (TieredCompilation) ShouldNotReachHere();
 445     MethodCounters* mcs = get_method_counters(CHECK_0);
 446     return (mcs == NULL) ? 0 : mcs->increment_interpreter_invocation_count();
 447   }
 448 #endif
 449 
 450 #ifndef PRODUCT
 451   int  compiled_invocation_count() const         { return _compiled_invocation_count;  }
 452   void set_compiled_invocation_count(int count)  { _compiled_invocation_count = count; }
 453 #else
 454   // for PrintMethodData in a product build
 455   int  compiled_invocation_count() const         { return 0;  }
 456 #endif // not PRODUCT
 457 
 458   // Clear (non-shared space) pointers which could not be relevant
 459   // if this (shared) method were mapped into another JVM.
 460   void remove_unshareable_info();
 461 
 462   // nmethod/verified compiler entry
 463   address verified_code_entry();
 464   bool check_code() const;      // Not inline to avoid circular ref
 465   CompiledMethod* volatile code() const;
 466   void clear_code(bool acquire_lock = true);    // Clear out any compiled code
 467   static void set_code(const methodHandle& mh, CompiledMethod* code);
 468   void set_adapter_entry(AdapterHandlerEntry* adapter) {
 469     constMethod()->set_adapter_entry(adapter);
 470   }
 471   void update_adapter_trampoline(AdapterHandlerEntry* adapter) {
 472     constMethod()->update_adapter_trampoline(adapter);
 473   }
 474 
 475   address get_i2c_entry();
 476   address get_c2i_entry();
 477   address get_c2i_unverified_entry();
 478   AdapterHandlerEntry* adapter() const {
 479     return constMethod()->adapter();
 480   }
 481   // setup entry points
 482   void link_method(const methodHandle& method, TRAPS);
 483   // clear entry points. Used by sharing code during dump time
 484   void unlink_method() NOT_CDS_RETURN;
 485 
 486   virtual void metaspace_pointers_do(MetaspaceClosure* iter);
 487   virtual MetaspaceObj::Type type() const { return MethodType; }
 488 
 489   // vtable index
 490   enum VtableIndexFlag {
 491     // Valid vtable indexes are non-negative (>= 0).
 492     // These few negative values are used as sentinels.
 493     itable_index_max        = -10, // first itable index, growing downward
 494     pending_itable_index    = -9,  // itable index will be assigned
 495     invalid_vtable_index    = -4,  // distinct from any valid vtable index
 496     garbage_vtable_index    = -3,  // not yet linked; no vtable layout yet
 497     nonvirtual_vtable_index = -2   // there is no need for vtable dispatch
 498     // 6330203 Note:  Do not use -1, which was overloaded with many meanings.
 499   };
 500   DEBUG_ONLY(bool valid_vtable_index() const     { return _vtable_index >= nonvirtual_vtable_index; })
 501   bool has_vtable_index() const                  { return _vtable_index >= 0; }
 502   int  vtable_index() const                      { return _vtable_index; }
 503   void set_vtable_index(int index);
 504   DEBUG_ONLY(bool valid_itable_index() const     { return _vtable_index <= pending_itable_index; })
 505   bool has_itable_index() const                  { return _vtable_index <= itable_index_max; }
 506   int  itable_index() const                      { assert(valid_itable_index(), "");
 507                                                    return itable_index_max - _vtable_index; }
 508   void set_itable_index(int index);
 509 
 510   // interpreter entry
 511   address interpreter_entry() const              { return _i2i_entry; }
 512   // Only used when first initialize so we can set _i2i_entry and _from_interpreted_entry
 513   void set_interpreter_entry(address entry) {
 514     assert(!is_shared(), "shared method's interpreter entry should not be changed at run time");
 515     if (_i2i_entry != entry) {
 516       _i2i_entry = entry;
 517     }
 518     if (_from_interpreted_entry != entry) {
 519       _from_interpreted_entry = entry;
 520     }
 521   }
 522 
 523   // native function (used for native methods only)
 524   enum {
 525     native_bind_event_is_interesting = true
 526   };
 527   address native_function() const                { return *(native_function_addr()); }
 528   address critical_native_function();
 529 
 530   // Must specify a real function (not NULL).
 531   // Use clear_native_function() to unregister.
 532   void set_native_function(address function, bool post_event_flag);
 533   bool has_native_function() const;
 534   void clear_native_function();
 535 
 536   // signature handler (used for native methods only)
 537   address signature_handler() const              { return *(signature_handler_addr()); }
 538   void set_signature_handler(address handler);
 539 
 540   // Interpreter oopmap support
 541   void mask_for(int bci, InterpreterOopMap* mask);
 542 
 543   // operations on invocation counter
 544   void print_invocation_count();
 545 
 546   // byte codes
 547   void    set_code(address code)      { return constMethod()->set_code(code); }
 548   address code_base() const           { return constMethod()->code_base(); }
 549   bool    contains(address bcp) const { return constMethod()->contains(bcp); }
 550 
 551   // prints byte codes
 552   void print_codes() const            { print_codes_on(tty); }
 553   void print_codes_on(outputStream* st) const;
 554   void print_codes_on(int from, int to, outputStream* st) const;
 555 
 556   // method parameters
 557   bool has_method_parameters() const
 558                          { return constMethod()->has_method_parameters(); }
 559   int method_parameters_length() const
 560                          { return constMethod()->method_parameters_length(); }
 561   MethodParametersElement* method_parameters_start() const
 562                           { return constMethod()->method_parameters_start(); }
 563 
 564   // checked exceptions
 565   int checked_exceptions_length() const
 566                          { return constMethod()->checked_exceptions_length(); }
 567   CheckedExceptionElement* checked_exceptions_start() const
 568                           { return constMethod()->checked_exceptions_start(); }
 569 
 570   // localvariable table
 571   bool has_localvariable_table() const
 572                           { return constMethod()->has_localvariable_table(); }
 573   int localvariable_table_length() const
 574                         { return constMethod()->localvariable_table_length(); }
 575   LocalVariableTableElement* localvariable_table_start() const
 576                          { return constMethod()->localvariable_table_start(); }
 577 
 578   bool has_linenumber_table() const
 579                               { return constMethod()->has_linenumber_table(); }
 580   u_char* compressed_linenumber_table() const
 581                        { return constMethod()->compressed_linenumber_table(); }
 582 
 583   // method holder (the Klass* holding this method)
 584   InstanceKlass* method_holder() const         { return constants()->pool_holder(); }
 585 
 586   void compute_size_of_parameters(Thread *thread); // word size of parameters (receiver if any + arguments)
 587   Symbol* klass_name() const;                    // returns the name of the method holder
 588   BasicType result_type() const;                 // type of the method result
 589   bool is_returning_oop() const                  { BasicType r = result_type(); return (r == T_OBJECT || r == T_ARRAY); }
 590   bool is_returning_fp() const                   { BasicType r = result_type(); return (r == T_FLOAT || r == T_DOUBLE); }
 591 
 592   // Checked exceptions thrown by this method (resolved to mirrors)
 593   objArrayHandle resolved_checked_exceptions(TRAPS) { return resolved_checked_exceptions_impl(this, THREAD); }
 594 
 595   // Access flags
 596   bool is_public() const                         { return access_flags().is_public();      }
 597   bool is_private() const                        { return access_flags().is_private();     }
 598   bool is_protected() const                      { return access_flags().is_protected();   }
 599   bool is_package_private() const                { return !is_public() && !is_private() && !is_protected(); }
 600   bool is_static() const                         { return access_flags().is_static();      }
 601   bool is_final() const                          { return access_flags().is_final();       }
 602   bool is_synchronized() const                   { return access_flags().is_synchronized();}
 603   bool is_native() const                         { return access_flags().is_native();      }
 604   bool is_abstract() const                       { return access_flags().is_abstract();    }
 605   bool is_strict() const                         { return access_flags().is_strict();      }
 606   bool is_synthetic() const                      { return access_flags().is_synthetic();   }
 607 
 608   // returns true if contains only return operation
 609   bool is_empty_method() const;
 610 
 611   // returns true if this is a vanilla constructor
 612   bool is_vanilla_constructor() const;
 613 
 614   // checks method and its method holder
 615   bool is_final_method() const;
 616   bool is_final_method(AccessFlags class_access_flags) const;
 617   // interface method declared with 'default' - excludes private interface methods
 618   bool is_default_method() const;
 619 
 620   // true if method needs no dynamic dispatch (final and/or no vtable entry)
 621   bool can_be_statically_bound() const;
 622   bool can_be_statically_bound(InstanceKlass* context) const;
 623   bool can_be_statically_bound(AccessFlags class_access_flags) const;
 624 
 625   // returns true if the method has any backward branches.
 626   bool has_loops() {
 627     return access_flags().loops_flag_init() ? access_flags().has_loops() : compute_has_loops_flag();
 628   };
 629 
 630   bool compute_has_loops_flag();
 631 
 632   bool has_jsrs() {
 633     return access_flags().has_jsrs();
 634   };
 635   void set_has_jsrs() {
 636     _access_flags.set_has_jsrs();
 637   }
 638 
 639   // returns true if the method has any monitors.
 640   bool has_monitors() const                      { return is_synchronized() || access_flags().has_monitor_bytecodes(); }
 641   bool has_monitor_bytecodes() const             { return access_flags().has_monitor_bytecodes(); }
 642 
 643   void set_has_monitor_bytecodes()               { _access_flags.set_has_monitor_bytecodes(); }
 644 
 645   // monitor matching. This returns a conservative estimate of whether the monitorenter/monitorexit bytecodes
 646   // propererly nest in the method. It might return false, even though they actually nest properly, since the info.
 647   // has not been computed yet.
 648   bool guaranteed_monitor_matching() const       { return access_flags().is_monitor_matching(); }
 649   void set_guaranteed_monitor_matching()         { _access_flags.set_monitor_matching(); }
 650 
 651   // returns true if the method is an accessor function (setter/getter).
 652   bool is_accessor() const;
 653 
 654   // returns true if the method is a getter
 655   bool is_getter() const;
 656 
 657   // returns true if the method is a setter
 658   bool is_setter() const;
 659 
 660   // returns true if the method does nothing but return a constant of primitive type
 661   bool is_constant_getter() const;
 662 
 663   // returns true if the method is an initializer (<init> or <clinit>).
 664   bool is_initializer() const;
 665 
 666   // returns true if the method is static OR if the classfile version < 51
 667   bool has_valid_initializer_flags() const;
 668 
 669   // returns true if the method name is <clinit> and the method has
 670   // valid static initializer flags.
 671   bool is_static_initializer() const;
 672 
 673   // returns true if the method name is <init>
 674   bool is_object_initializer() const;
 675 
 676   // compiled code support
 677   // NOTE: code() is inherently racy as deopt can be clearing code
 678   // simultaneously. Use with caution.
 679   bool has_compiled_code() const;
 680 
 681 #ifdef TIERED
 682   bool has_aot_code() const                      { return aot_code() != NULL; }
 683 #endif
 684 
 685   bool needs_clinit_barrier() const;
 686 
 687   // sizing
 688   static int header_size()                       {
 689     return align_up((int)sizeof(Method), wordSize) / wordSize;
 690   }
 691   static int size(bool is_native);
 692   int size() const                               { return method_size(); }
 693 #if INCLUDE_SERVICES
 694   void collect_statistics(KlassSizeStats *sz) const;
 695 #endif
 696   void log_touched(TRAPS);
 697   static void print_touched_methods(outputStream* out);
 698 
 699   // interpreter support
 700   static ByteSize const_offset()                 { return byte_offset_of(Method, _constMethod       ); }
 701   static ByteSize access_flags_offset()          { return byte_offset_of(Method, _access_flags      ); }
 702   static ByteSize from_compiled_offset()         { return byte_offset_of(Method, _from_compiled_entry); }
 703   static ByteSize code_offset()                  { return byte_offset_of(Method, _code); }
 704   static ByteSize method_data_offset()           {
 705     return byte_offset_of(Method, _method_data);
 706   }
 707   static ByteSize method_counters_offset()       {
 708     return byte_offset_of(Method, _method_counters);
 709   }
 710 #ifndef PRODUCT
 711   static ByteSize compiled_invocation_counter_offset() { return byte_offset_of(Method, _compiled_invocation_count); }
 712 #endif // not PRODUCT
 713   static ByteSize native_function_offset()       { return in_ByteSize(sizeof(Method));                 }
 714   static ByteSize from_interpreted_offset()      { return byte_offset_of(Method, _from_interpreted_entry ); }
 715   static ByteSize interpreter_entry_offset()     { return byte_offset_of(Method, _i2i_entry ); }
 716   static ByteSize signature_handler_offset()     { return in_ByteSize(sizeof(Method) + wordSize);      }
 717   static ByteSize itable_index_offset()          { return byte_offset_of(Method, _vtable_index ); }
 718 
 719   // for code generation
 720   static int method_data_offset_in_bytes()       { return offset_of(Method, _method_data); }
 721   static int intrinsic_id_offset_in_bytes()      { return offset_of(Method, _intrinsic_id); }
 722   static int intrinsic_id_size_in_bytes()        { return sizeof(u2); }
 723 
 724   // Static methods that are used to implement member methods where an exposed this pointer
 725   // is needed due to possible GCs
 726   static objArrayHandle resolved_checked_exceptions_impl(Method* method, TRAPS);
 727 
 728   // Returns the byte code index from the byte code pointer
 729   int     bci_from(address bcp) const;
 730   address bcp_from(int bci) const;
 731   address bcp_from(address bcp) const;
 732   int validate_bci_from_bcp(address bcp) const;
 733   int validate_bci(int bci) const;
 734 
 735   // Returns the line number for a bci if debugging information for the method is prowided,
 736   // -1 is returned otherwise.
 737   int line_number_from_bci(int bci) const;
 738 
 739   // Reflection support
 740   bool is_overridden_in(Klass* k) const;
 741 
 742   // Stack walking support
 743   bool is_ignored_by_security_stack_walk() const;
 744 
 745   // JSR 292 support
 746   bool is_method_handle_intrinsic() const;          // MethodHandles::is_signature_polymorphic_intrinsic(intrinsic_id)
 747   bool is_compiled_lambda_form() const;             // intrinsic_id() == vmIntrinsics::_compiledLambdaForm
 748   bool has_member_arg() const;                      // intrinsic_id() == vmIntrinsics::_linkToSpecial, etc.
 749   static methodHandle make_method_handle_intrinsic(vmIntrinsics::ID iid, // _invokeBasic, _linkToVirtual
 750                                                    Symbol* signature, //anything at all
 751                                                    TRAPS);
 752   static Klass* check_non_bcp_klass(Klass* klass);
 753 
 754   enum {
 755     // How many extra stack entries for invokedynamic
 756     extra_stack_entries_for_jsr292 = 1
 757   };
 758 
 759   // this operates only on invoke methods:
 760   // presize interpreter frames for extra interpreter stack entries, if needed
 761   // Account for the extra appendix argument for invokehandle/invokedynamic
 762   static int extra_stack_entries() { return extra_stack_entries_for_jsr292; }
 763   static int extra_stack_words();  // = extra_stack_entries() * Interpreter::stackElementSize
 764 
 765   // RedefineClasses() support:
 766   bool is_old() const                               { return access_flags().is_old(); }
 767   void set_is_old()                                 { _access_flags.set_is_old(); }
 768   bool is_obsolete() const                          { return access_flags().is_obsolete(); }
 769   void set_is_obsolete()                            { _access_flags.set_is_obsolete(); }
 770   bool is_deleted() const                           { return access_flags().is_deleted(); }
 771   void set_is_deleted()                             { _access_flags.set_is_deleted(); }
 772 
 773   bool is_running_emcp() const {
 774     // EMCP methods are old but not obsolete or deleted. Equivalent
 775     // Modulo Constant Pool means the method is equivalent except
 776     // the constant pool and instructions that access the constant
 777     // pool might be different.
 778     // If a breakpoint is set in a redefined method, its EMCP methods that are
 779     // still running must have a breakpoint also.
 780     return (_flags & _running_emcp) != 0;
 781   }
 782 
 783   void set_running_emcp(bool x) {
 784     _flags = x ? (_flags | _running_emcp) : (_flags & ~_running_emcp);
 785   }
 786 
 787   bool on_stack() const                             { return access_flags().on_stack(); }
 788   void set_on_stack(const bool value);
 789 
 790   // see the definition in Method*.cpp for the gory details
 791   bool should_not_be_cached() const;
 792 
 793   // JVMTI Native method prefixing support:
 794   bool is_prefixed_native() const                   { return access_flags().is_prefixed_native(); }
 795   void set_is_prefixed_native()                     { _access_flags.set_is_prefixed_native(); }
 796 
 797   // Rewriting support
 798   static methodHandle clone_with_new_data(const methodHandle& m, u_char* new_code, int new_code_length,
 799                                           u_char* new_compressed_linenumber_table, int new_compressed_linenumber_size, TRAPS);
 800 
 801   // jmethodID handling
 802   // Because the useful life-span of a jmethodID cannot be determined,
 803   // once created they are never reclaimed.  The methods to which they refer,
 804   // however, can be GC'ed away if the class is unloaded or if the method is
 805   // made obsolete or deleted -- in these cases, the jmethodID
 806   // refers to NULL (as is the case for any weak reference).
 807   static jmethodID make_jmethod_id(ClassLoaderData* loader_data, Method* mh);
 808   static void destroy_jmethod_id(ClassLoaderData* loader_data, jmethodID mid);
 809 
 810   // Ensure there is enough capacity in the internal tracking data
 811   // structures to hold the number of jmethodIDs you plan to generate.
 812   // This saves substantial time doing allocations.
 813   static void ensure_jmethod_ids(ClassLoaderData* loader_data, int capacity);
 814 
 815   // Use resolve_jmethod_id() in situations where the caller is expected
 816   // to provide a valid jmethodID; the only sanity checks are in asserts;
 817   // result guaranteed not to be NULL.
 818   inline static Method* resolve_jmethod_id(jmethodID mid) {
 819     assert(mid != NULL, "JNI method id should not be null");
 820     return *((Method**)mid);
 821   }
 822 
 823   // Use checked_resolve_jmethod_id() in situations where the caller
 824   // should provide a valid jmethodID, but might not. NULL is returned
 825   // when the jmethodID does not refer to a valid method.
 826   static Method* checked_resolve_jmethod_id(jmethodID mid);
 827 
 828   static void change_method_associated_with_jmethod_id(jmethodID old_jmid_ptr, Method* new_method);
 829   static bool is_method_id(jmethodID mid);
 830 
 831   // Clear methods
 832   static void clear_jmethod_ids(ClassLoaderData* loader_data);
 833   static void print_jmethod_ids(const ClassLoaderData* loader_data, outputStream* out) PRODUCT_RETURN;
 834 
 835   // Get this method's jmethodID -- allocate if it doesn't exist
 836   jmethodID jmethod_id()                            { return method_holder()->get_jmethod_id(this); }
 837 
 838   // Lookup the jmethodID for this method.  Return NULL if not found.
 839   // NOTE that this function can be called from a signal handler
 840   // (see AsyncGetCallTrace support for Forte Analyzer) and this
 841   // needs to be async-safe. No allocation should be done and
 842   // so handles are not used to avoid deadlock.
 843   jmethodID find_jmethod_id_or_null()               { return method_holder()->jmethod_id_or_null(this); }
 844 
 845   // Support for inlining of intrinsic methods
 846   vmIntrinsics::ID intrinsic_id() const          { return (vmIntrinsics::ID) _intrinsic_id;           }
 847   void     set_intrinsic_id(vmIntrinsics::ID id) {                           _intrinsic_id = (u2) id; }
 848 
 849   // Helper routines for intrinsic_id() and vmIntrinsics::method().
 850   void init_intrinsic_id();     // updates from _none if a match
 851   static vmSymbols::SID klass_id_for_intrinsics(const Klass* holder);
 852 
 853   bool caller_sensitive() {
 854     return (_flags & _caller_sensitive) != 0;
 855   }
 856   void set_caller_sensitive(bool x) {
 857     _flags = x ? (_flags | _caller_sensitive) : (_flags & ~_caller_sensitive);
 858   }
 859 
 860   bool force_inline() {
 861     return (_flags & _force_inline) != 0;
 862   }
 863   void set_force_inline(bool x) {
 864     _flags = x ? (_flags | _force_inline) : (_flags & ~_force_inline);
 865   }
 866 
 867   bool dont_inline() {
 868     return (_flags & _dont_inline) != 0;
 869   }
 870   void set_dont_inline(bool x) {
 871     _flags = x ? (_flags | _dont_inline) : (_flags & ~_dont_inline);
 872   }
 873 
 874   bool is_hidden() {
 875     return (_flags & _hidden) != 0;
 876   }
 877   void set_hidden(bool x) {
 878     _flags = x ? (_flags | _hidden) : (_flags & ~_hidden);
 879   }
 880 
 881   bool intrinsic_candidate() {
 882     return (_flags & _intrinsic_candidate) != 0;
 883   }
 884   void set_intrinsic_candidate(bool x) {
 885     _flags = x ? (_flags | _intrinsic_candidate) : (_flags & ~_intrinsic_candidate);
 886   }
 887 
 888   bool has_injected_profile() {
 889     return (_flags & _has_injected_profile) != 0;
 890   }
 891   void set_has_injected_profile(bool x) {
 892     _flags = x ? (_flags | _has_injected_profile) : (_flags & ~_has_injected_profile);
 893   }
 894 
 895   bool has_reserved_stack_access() {
 896     return (_flags & _reserved_stack_access) != 0;
 897   }
 898 
 899   void set_has_reserved_stack_access(bool x) {
 900     _flags = x ? (_flags | _reserved_stack_access) : (_flags & ~_reserved_stack_access);
 901   }
 902 
 903   JFR_ONLY(DEFINE_TRACE_FLAG_ACCESSOR;)
 904 
 905   ConstMethod::MethodType method_type() const {
 906       return _constMethod->method_type();
 907   }
 908   bool is_overpass() const { return method_type() == ConstMethod::OVERPASS; }
 909 
 910   // On-stack replacement support
 911   bool has_osr_nmethod(int level, bool match_level) {
 912    return method_holder()->lookup_osr_nmethod(this, InvocationEntryBci, level, match_level) != NULL;
 913   }
 914 
 915   int mark_osr_nmethods() {
 916     return method_holder()->mark_osr_nmethods(this);
 917   }
 918 
 919   nmethod* lookup_osr_nmethod_for(int bci, int level, bool match_level) {
 920     return method_holder()->lookup_osr_nmethod(this, bci, level, match_level);
 921   }
 922 
 923   // Find if klass for method is loaded
 924   bool is_klass_loaded_by_klass_index(int klass_index) const;
 925   bool is_klass_loaded(int refinfo_index, bool must_be_resolved = false) const;
 926 
 927   // Indicates whether compilation failed earlier for this method, or
 928   // whether it is not compilable for another reason like having a
 929   // breakpoint set in it.
 930   bool  is_not_compilable(int comp_level = CompLevel_any) const;
 931   void set_not_compilable(int comp_level = CompLevel_all, bool report = true, const char* reason = NULL);
 932   void set_not_compilable_quietly(int comp_level = CompLevel_all) {
 933     set_not_compilable(comp_level, false);
 934   }
 935   bool  is_not_osr_compilable(int comp_level = CompLevel_any) const;
 936   void set_not_osr_compilable(int comp_level = CompLevel_all, bool report = true, const char* reason = NULL);
 937   void set_not_osr_compilable_quietly(int comp_level = CompLevel_all) {
 938     set_not_osr_compilable(comp_level, false);
 939   }
 940   bool is_always_compilable() const;
 941 
 942  private:
 943   void print_made_not_compilable(int comp_level, bool is_osr, bool report, const char* reason);
 944 
 945  public:
 946   MethodCounters* get_method_counters(TRAPS) {
 947     if (_method_counters == NULL) {
 948       build_method_counters(this, CHECK_AND_CLEAR_NULL);
 949     }
 950     return _method_counters;
 951   }
 952 
 953   bool   is_not_c1_compilable() const         { return access_flags().is_not_c1_compilable();  }
 954   void  set_not_c1_compilable()               {       _access_flags.set_not_c1_compilable();   }
 955   void clear_not_c1_compilable()              {       _access_flags.clear_not_c1_compilable(); }
 956   bool   is_not_c2_compilable() const         { return access_flags().is_not_c2_compilable();  }
 957   void  set_not_c2_compilable()               {       _access_flags.set_not_c2_compilable();   }
 958   void clear_not_c2_compilable()              {       _access_flags.clear_not_c2_compilable(); }
 959 
 960   bool    is_not_c1_osr_compilable() const    { return is_not_c1_compilable(); }  // don't waste an accessFlags bit
 961   void   set_not_c1_osr_compilable()          {       set_not_c1_compilable(); }  // don't waste an accessFlags bit
 962   void clear_not_c1_osr_compilable()          {     clear_not_c1_compilable(); }  // don't waste an accessFlags bit
 963   bool   is_not_c2_osr_compilable() const     { return access_flags().is_not_c2_osr_compilable();  }
 964   void  set_not_c2_osr_compilable()           {       _access_flags.set_not_c2_osr_compilable();   }
 965   void clear_not_c2_osr_compilable()          {       _access_flags.clear_not_c2_osr_compilable(); }
 966 
 967   // Background compilation support
 968   bool queued_for_compilation() const  { return access_flags().queued_for_compilation(); }
 969   void set_queued_for_compilation()    { _access_flags.set_queued_for_compilation();     }
 970   void clear_queued_for_compilation()  { _access_flags.clear_queued_for_compilation();   }
 971 
 972   // Resolve all classes in signature, return 'true' if successful
 973   static bool load_signature_classes(const methodHandle& m, TRAPS);
 974 
 975   // Return if true if not all classes references in signature, including return type, has been loaded
 976   static bool has_unloaded_classes_in_signature(const methodHandle& m, TRAPS);
 977 
 978   // Printing
 979   void print_short_name(outputStream* st = tty); // prints as klassname::methodname; Exposed so field engineers can debug VM
 980 #if INCLUDE_JVMTI
 981   void print_name(outputStream* st = tty); // prints as "virtual void foo(int)"; exposed for TraceRedefineClasses
 982 #else
 983   void print_name(outputStream* st = tty)        PRODUCT_RETURN; // prints as "virtual void foo(int)"
 984 #endif
 985 
 986   // Helper routine used for method sorting
 987   static void sort_methods(Array<Method*>* methods, bool set_idnums = true);
 988 
 989   // Deallocation function for redefine classes or if an error occurs
 990   void deallocate_contents(ClassLoaderData* loader_data);
 991 
 992   Method* get_new_method() const {
 993     InstanceKlass* holder = method_holder();
 994     Method* new_method = holder->method_with_idnum(orig_method_idnum());
 995 
 996     assert(new_method != NULL, "method_with_idnum() should not be NULL");
 997     assert(this != new_method, "sanity check");
 998     return new_method;
 999   }
1000 
1001   // Printing
1002 #ifndef PRODUCT
1003   void print_on(outputStream* st) const;
1004 #endif
1005   void print_value_on(outputStream* st) const;
1006   void print_linkage_flags(outputStream* st) PRODUCT_RETURN;
1007 
1008   const char* internal_name() const { return "{method}"; }
1009 
1010   // Check for valid method pointer
1011   static bool has_method_vptr(const void* ptr);
1012   static bool is_valid_method(const Method* m);
1013 
1014   // Verify
1015   void verify() { verify_on(tty); }
1016   void verify_on(outputStream* st);
1017 
1018  private:
1019 
1020   // Inlined elements
1021   address* native_function_addr() const          { assert(is_native(), "must be native"); return (address*) (this+1); }
1022   address* signature_handler_addr() const        { return native_function_addr() + 1; }
1023 };
1024 
1025 
1026 // Utility class for compressing line number tables
1027 
1028 class CompressedLineNumberWriteStream: public CompressedWriteStream {
1029  private:
1030   int _bci;
1031   int _line;
1032  public:
1033   // Constructor
1034   CompressedLineNumberWriteStream(int initial_size) : CompressedWriteStream(initial_size), _bci(0), _line(0) {}
1035   CompressedLineNumberWriteStream(u_char* buffer, int initial_size) : CompressedWriteStream(buffer, initial_size), _bci(0), _line(0) {}
1036 
1037   // Write (bci, line number) pair to stream
1038   void write_pair_regular(int bci_delta, int line_delta);
1039 
1040   // If (bci delta, line delta) fits in (5-bit unsigned, 3-bit unsigned)
1041   // we save it as one byte, otherwise we write a 0xFF escape character
1042   // and use regular compression. 0x0 is used as end-of-stream terminator.
1043   void write_pair_inline(int bci, int line);
1044 
1045   void write_pair(int bci, int line);
1046 
1047   // Write end-of-stream marker
1048   void write_terminator()                        { write_byte(0); }
1049 };
1050 
1051 
1052 // Utility class for decompressing line number tables
1053 
1054 class CompressedLineNumberReadStream: public CompressedReadStream {
1055  private:
1056   int _bci;
1057   int _line;
1058  public:
1059   // Constructor
1060   CompressedLineNumberReadStream(u_char* buffer);
1061   // Read (bci, line number) pair from stream. Returns false at end-of-stream.
1062   bool read_pair();
1063   // Accessing bci and line number (after calling read_pair)
1064   int bci() const                               { return _bci; }
1065   int line() const                              { return _line; }
1066 };
1067 
1068 
1069 #if INCLUDE_JVMTI
1070 
1071 /// Fast Breakpoints.
1072 
1073 // If this structure gets more complicated (because bpts get numerous),
1074 // move it into its own header.
1075 
1076 // There is presently no provision for concurrent access
1077 // to breakpoint lists, which is only OK for JVMTI because
1078 // breakpoints are written only at safepoints, and are read
1079 // concurrently only outside of safepoints.
1080 
1081 class BreakpointInfo : public CHeapObj<mtClass> {
1082   friend class VMStructs;
1083  private:
1084   Bytecodes::Code  _orig_bytecode;
1085   int              _bci;
1086   u2               _name_index;       // of method
1087   u2               _signature_index;  // of method
1088   BreakpointInfo*  _next;             // simple storage allocation
1089 
1090  public:
1091   BreakpointInfo(Method* m, int bci);
1092 
1093   // accessors
1094   Bytecodes::Code orig_bytecode()                     { return _orig_bytecode; }
1095   void        set_orig_bytecode(Bytecodes::Code code) { _orig_bytecode = code; }
1096   int         bci()                                   { return _bci; }
1097 
1098   BreakpointInfo*          next() const               { return _next; }
1099   void                 set_next(BreakpointInfo* n)    { _next = n; }
1100 
1101   // helps for searchers
1102   bool match(const Method* m, int bci) {
1103     return bci == _bci && match(m);
1104   }
1105 
1106   bool match(const Method* m) {
1107     return _name_index == m->name_index() &&
1108       _signature_index == m->signature_index();
1109   }
1110 
1111   void set(Method* method);
1112   void clear(Method* method);
1113 };
1114 
1115 #endif // INCLUDE_JVMTI
1116 
1117 // Utility class for access exception handlers
1118 class ExceptionTable : public StackObj {
1119  private:
1120   ExceptionTableElement* _table;
1121   u2  _length;
1122 
1123  public:
1124   ExceptionTable(const Method* m) {
1125     if (m->has_exception_handler()) {
1126       _table = m->exception_table_start();
1127       _length = m->exception_table_length();
1128     } else {
1129       _table = NULL;
1130       _length = 0;
1131     }
1132   }
1133 
1134   int length() const {
1135     return _length;
1136   }
1137 
1138   u2 start_pc(int idx) const {
1139     assert(idx < _length, "out of bounds");
1140     return _table[idx].start_pc;
1141   }
1142 
1143   void set_start_pc(int idx, u2 value) {
1144     assert(idx < _length, "out of bounds");
1145     _table[idx].start_pc = value;
1146   }
1147 
1148   u2 end_pc(int idx) const {
1149     assert(idx < _length, "out of bounds");
1150     return _table[idx].end_pc;
1151   }
1152 
1153   void set_end_pc(int idx, u2 value) {
1154     assert(idx < _length, "out of bounds");
1155     _table[idx].end_pc = value;
1156   }
1157 
1158   u2 handler_pc(int idx) const {
1159     assert(idx < _length, "out of bounds");
1160     return _table[idx].handler_pc;
1161   }
1162 
1163   void set_handler_pc(int idx, u2 value) {
1164     assert(idx < _length, "out of bounds");
1165     _table[idx].handler_pc = value;
1166   }
1167 
1168   u2 catch_type_index(int idx) const {
1169     assert(idx < _length, "out of bounds");
1170     return _table[idx].catch_type_index;
1171   }
1172 
1173   void set_catch_type_index(int idx, u2 value) {
1174     assert(idx < _length, "out of bounds");
1175     _table[idx].catch_type_index = value;
1176   }
1177 };
1178 
1179 #endif // SHARE_OOPS_METHOD_HPP