Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "code/codeCache.hpp"

 #include "code/compiledIC.hpp"

 #include "code/dependencies.hpp"

 #include "code/nmethod.hpp"

 #include "code/scopeDesc.hpp"

 #include "compiler/abstractCompiler.hpp"

 #include "compiler/compileBroker.hpp"

 #include "compiler/compileLog.hpp"

 #include "compiler/compilerOracle.hpp"

 #include "compiler/disassembler.hpp"

 #include "interpreter/bytecode.hpp"

 #include "oops/methodData.hpp"

 #include "prims/jvmtiRedefineClassesTrace.hpp"

 #include "prims/jvmtiImpl.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "runtime/sweeper.hpp"

 #include "utilities/dtrace.hpp"

 #include "utilities/events.hpp"

 #include "utilities/xmlstream.hpp"

 #ifdef SHARK

 #include "shark/sharkCompiler.hpp"

 #endif

 #ifdef DTRACE_ENABLED

 // Only bother with this argument setup if dtrace is available

 #ifndef USDT2

 HS_DTRACE_PROBE_DECL8(hotspot, compiled__method__load,

   const char*, int, const char*, int, const char*, int, void*, size_t);

 HS_DTRACE_PROBE_DECL6(hotspot, compiled__method__unload,

   char*, int, char*, int, char*, int);

 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \

   {                                                                       \

     Method* m = (method);                                                 \

     if (m != NULL) {                                                      \

       Symbol* klass_name = m->klass_name();                               \

       Symbol* name = m->name();                                           \

       Symbol* signature = m->signature();                                 \

       HS_DTRACE_PROBE6(hotspot, compiled__method__unload,                 \

         klass_name->bytes(), klass_name->utf8_length(),                   \

         name->bytes(), name->utf8_length(),                               \

         signature->bytes(), signature->utf8_length());                    \

     }                                                                     \

   }

 #else /* USDT2 */

 #define DTRACE_METHOD_UNLOAD_PROBE(method)                                \

   {                                                                       \

     Method* m = (method);                                                 \

     if (m != NULL) {                                                      \

       Symbol* klass_name = m->klass_name();                               \

       Symbol* name = m->name();                                           \

       Symbol* signature = m->signature();                                 \

       HOTSPOT_COMPILED_METHOD_UNLOAD(                                     \

         (char *) klass_name->bytes(), klass_name->utf8_length(),                   \

         (char *) name->bytes(), name->utf8_length(),                               \

         (char *) signature->bytes(), signature->utf8_length());                    \

     }                                                                     \

   }

 #endif /* USDT2 */

 #else //  ndef DTRACE_ENABLED

 #define DTRACE_METHOD_UNLOAD_PROBE(method)

 #endif

 bool nmethod::is_compiled_by_c1() const {

   if (compiler() == NULL) {

     return false;

   }

   return compiler()->is_c1();

 }

 bool nmethod::is_compiled_by_c2() const {

   if (compiler() == NULL) {

     return false;

   }

   return compiler()->is_c2();

 }

 bool nmethod::is_compiled_by_shark() const {

   if (compiler() == NULL) {

     return false;

   }

   return compiler()->is_shark();

 }

 //---------------------------------------------------------------------------------

 // NMethod statistics

 // They are printed under various flags, including:

 //   PrintC1Statistics, PrintOptoStatistics, LogVMOutput, and LogCompilation.

 // (In the latter two cases, they like other stats are printed to the log only.)

 #ifndef PRODUCT

 // These variables are put into one block to reduce relocations

 // and make it simpler to print from the debugger.

 static

 struct nmethod_stats_struct {

   int nmethod_count;

   int total_size;

   int relocation_size;

   int consts_size;

   int insts_size;

   int stub_size;

   int scopes_data_size;

   int scopes_pcs_size;

   int dependencies_size;

   int handler_table_size;

   int nul_chk_table_size;

   int oops_size;

   void note_nmethod(nmethod* nm) {

     nmethod_count += 1;

     total_size          += nm->size();

     relocation_size     += nm->relocation_size();

     consts_size         += nm->consts_size();

     insts_size          += nm->insts_size();

     stub_size           += nm->stub_size();

     oops_size           += nm->oops_size();

     scopes_data_size    += nm->scopes_data_size();

     scopes_pcs_size     += nm->scopes_pcs_size();

     dependencies_size   += nm->dependencies_size();

     handler_table_size  += nm->handler_table_size();

     nul_chk_table_size  += nm->nul_chk_table_size();

   }

   void print_nmethod_stats() {

     if (nmethod_count == 0)  return;

     tty->print_cr("Statistics for %d bytecoded nmethods:", nmethod_count);

     if (total_size != 0)          tty->print_cr(" total in heap  = %d", total_size);

     if (relocation_size != 0)     tty->print_cr(" relocation     = %d", relocation_size);

     if (consts_size != 0)         tty->print_cr(" constants      = %d", consts_size);

     if (insts_size != 0)          tty->print_cr(" main code      = %d", insts_size);

     if (stub_size != 0)           tty->print_cr(" stub code      = %d", stub_size);

     if (oops_size != 0)           tty->print_cr(" oops           = %d", oops_size);

     if (scopes_data_size != 0)    tty->print_cr(" scopes data    = %d", scopes_data_size);

     if (scopes_pcs_size != 0)     tty->print_cr(" scopes pcs     = %d", scopes_pcs_size);

     if (dependencies_size != 0)   tty->print_cr(" dependencies   = %d", dependencies_size);

     if (handler_table_size != 0)  tty->print_cr(" handler table  = %d", handler_table_size);

     if (nul_chk_table_size != 0)  tty->print_cr(" nul chk table  = %d", nul_chk_table_size);

   }

   int native_nmethod_count;

   int native_total_size;

   int native_relocation_size;

   int native_insts_size;

   int native_oops_size;

   void note_native_nmethod(nmethod* nm) {

     native_nmethod_count += 1;

     native_total_size       += nm->size();

     native_relocation_size  += nm->relocation_size();

     native_insts_size       += nm->insts_size();

     native_oops_size        += nm->oops_size();

   }

   void print_native_nmethod_stats() {

     if (native_nmethod_count == 0)  return;

     tty->print_cr("Statistics for %d native nmethods:", native_nmethod_count);

     if (native_total_size != 0)       tty->print_cr(" N. total size  = %d", native_total_size);

     if (native_relocation_size != 0)  tty->print_cr(" N. relocation  = %d", native_relocation_size);

     if (native_insts_size != 0)       tty->print_cr(" N. main code   = %d", native_insts_size);

     if (native_oops_size != 0)        tty->print_cr(" N. oops        = %d", native_oops_size);

   }

   int pc_desc_resets;   // number of resets (= number of caches)

   int pc_desc_queries;  // queries to nmethod::find_pc_desc

   int pc_desc_approx;   // number of those which have approximate true

   int pc_desc_repeats;  // number of _pc_descs[0] hits

   int pc_desc_hits;     // number of LRU cache hits

   int pc_desc_tests;    // total number of PcDesc examinations

   int pc_desc_searches; // total number of quasi-binary search steps

   int pc_desc_adds;     // number of LUR cache insertions

   void print_pc_stats() {

     tty->print_cr("PcDesc Statistics:  %d queries, %.2f comparisons per query",

                   pc_desc_queries,

                   (double)(pc_desc_tests + pc_desc_searches)

                   / pc_desc_queries);

     tty->print_cr("  caches=%d queries=%d/%d, hits=%d+%d, tests=%d+%d, adds=%d",

                   pc_desc_resets,

                   pc_desc_queries, pc_desc_approx,

                   pc_desc_repeats, pc_desc_hits,

                   pc_desc_tests, pc_desc_searches, pc_desc_adds);

   }

 } nmethod_stats;

 #endif //PRODUCT

 //---------------------------------------------------------------------------------

 ExceptionCache::ExceptionCache(Handle exception, address pc, address handler) {

   assert(pc != NULL, "Must be non null");

   assert(exception.not_null(), "Must be non null");

   assert(handler != NULL, "Must be non null");

   _count = 0;

   _exception_type = exception->klass();

   _next = NULL;

   add_address_and_handler(pc,handler);

 }

 address ExceptionCache::match(Handle exception, address pc) {

   assert(pc != NULL,"Must be non null");

   assert(exception.not_null(),"Must be non null");

   if (exception->klass() == exception_type()) {

     return (test_address(pc));

   }

   return NULL;

 }

 bool ExceptionCache::match_exception_with_space(Handle exception) {

   assert(exception.not_null(),"Must be non null");

   if (exception->klass() == exception_type() && count() < cache_size) {

     return true;

   }

   return false;

 }

 address ExceptionCache::test_address(address addr) {

   for (int i=0; i<count(); i++) {

     if (pc_at(i) == addr) {

       return handler_at(i);

     }

   }

   return NULL;

 }

 bool ExceptionCache::add_address_and_handler(address addr, address handler) {

   if (test_address(addr) == handler) return true;

   if (count() < cache_size) {

     set_pc_at(count(),addr);

     set_handler_at(count(), handler);

     increment_count();

     return true;

   }

   return false;

 }

 // private method for handling exception cache

 // These methods are private, and used to manipulate the exception cache

 // directly.

 ExceptionCache* nmethod::exception_cache_entry_for_exception(Handle exception) {

   ExceptionCache* ec = exception_cache();

   while (ec != NULL) {

     if (ec->match_exception_with_space(exception)) {

       return ec;

     }

     ec = ec->next();

   }

   return NULL;

 }

 //-----------------------------------------------------------------------------

 // Helper used by both find_pc_desc methods.

 static inline bool match_desc(PcDesc* pc, int pc_offset, bool approximate) {

   NOT_PRODUCT(++nmethod_stats.pc_desc_tests);

   if (!approximate)

     return pc->pc_offset() == pc_offset;

   else

     return (pc-1)->pc_offset() < pc_offset && pc_offset <= pc->pc_offset();

 }

 void PcDescCache::reset_to(PcDesc* initial_pc_desc) {

   if (initial_pc_desc == NULL) {

     _pc_descs[0] = NULL; // native method; no PcDescs at all

     return;

   }

   NOT_PRODUCT(++nmethod_stats.pc_desc_resets);

   // reset the cache by filling it with benign (non-null) values

   assert(initial_pc_desc->pc_offset() < 0, "must be sentinel");

   for (int i = 0; i < cache_size; i++)

     _pc_descs[i] = initial_pc_desc;

 }

 PcDesc* PcDescCache::find_pc_desc(int pc_offset, bool approximate) {

   NOT_PRODUCT(++nmethod_stats.pc_desc_queries);

   NOT_PRODUCT(if (approximate) ++nmethod_stats.pc_desc_approx);

   // Note: one might think that caching the most recently

   // read value separately would be a win, but one would be

   // wrong.  When many threads are updating it, the cache

   // line it's in would bounce between caches, negating

   // any benefit.

   // In order to prevent race conditions do not load cache elements

   // repeatedly, but use a local copy:

   PcDesc* res;

   // Step one:  Check the most recently added value.

   res = _pc_descs[0];

   if (res == NULL) return NULL;  // native method; no PcDescs at all

   if (match_desc(res, pc_offset, approximate)) {

     NOT_PRODUCT(++nmethod_stats.pc_desc_repeats);

     return res;

   }

   // Step two:  Check the rest of the LRU cache.

   for (int i = 1; i < cache_size; ++i) {

     res = _pc_descs[i];

     if (res->pc_offset() < 0) break;  // optimization: skip empty cache

     if (match_desc(res, pc_offset, approximate)) {

       NOT_PRODUCT(++nmethod_stats.pc_desc_hits);

       return res;

     }

   }

   // Report failure.

   return NULL;

 }

 void PcDescCache::add_pc_desc(PcDesc* pc_desc) {

   NOT_PRODUCT(++nmethod_stats.pc_desc_adds);

   // Update the LRU cache by shifting pc_desc forward.

   for (int i = 0; i < cache_size; i++)  {

     PcDesc* next = _pc_descs[i];

     _pc_descs[i] = pc_desc;

     pc_desc = next;

   }

 }

 // adjust pcs_size so that it is a multiple of both oopSize and

 // sizeof(PcDesc) (assumes that if sizeof(PcDesc) is not a multiple

 // of oopSize, then 2*sizeof(PcDesc) is)

 static int adjust_pcs_size(int pcs_size) {

   int nsize = round_to(pcs_size,   oopSize);

   if ((nsize % sizeof(PcDesc)) != 0) {

     nsize = pcs_size + sizeof(PcDesc);

   }

   assert((nsize % oopSize) == 0, "correct alignment");

   return nsize;

 }

 //-----------------------------------------------------------------------------

 void nmethod::add_exception_cache_entry(ExceptionCache* new_entry) {

   assert(ExceptionCache_lock->owned_by_self(),"Must hold the ExceptionCache_lock");

   assert(new_entry != NULL,"Must be non null");

   assert(new_entry->next() == NULL, "Must be null");

   if (exception_cache() != NULL) {

     new_entry->set_next(exception_cache());

   }

   set_exception_cache(new_entry);

 }

 void nmethod::remove_from_exception_cache(ExceptionCache* ec) {

   ExceptionCache* prev = NULL;

   ExceptionCache* curr = exception_cache();

   assert(curr != NULL, "nothing to remove");

   // find the previous and next entry of ec

   while (curr != ec) {

     prev = curr;

     curr = curr->next();

     assert(curr != NULL, "ExceptionCache not found");

   }

   // now: curr == ec

   ExceptionCache* next = curr->next();

   if (prev == NULL) {

     set_exception_cache(next);

   } else {

     prev->set_next(next);

   }

   delete curr;

 }

 // public method for accessing the exception cache

 // These are the public access methods.

 address nmethod::handler_for_exception_and_pc(Handle exception, address pc) {

   // We never grab a lock to read the exception cache, so we may

   // have false negatives. This is okay, as it can only happen during

   // the first few exception lookups for a given nmethod.

   ExceptionCache* ec = exception_cache();

   while (ec != NULL) {

     address ret_val;

     if ((ret_val = ec->match(exception,pc)) != NULL) {

       return ret_val;

     }

     ec = ec->next();

   }

   return NULL;

 }

 void nmethod::add_handler_for_exception_and_pc(Handle exception, address pc, address handler) {

   // There are potential race conditions during exception cache updates, so we

   // must own the ExceptionCache_lock before doing ANY modifications. Because

   // we don't lock during reads, it is possible to have several threads attempt

   // to update the cache with the same data. We need to check for already inserted

   // copies of the current data before adding it.

   MutexLocker ml(ExceptionCache_lock);

   ExceptionCache* target_entry = exception_cache_entry_for_exception(exception);

   if (target_entry == NULL || !target_entry->add_address_and_handler(pc,handler)) {

     target_entry = new ExceptionCache(exception,pc,handler);

     add_exception_cache_entry(target_entry);

   }

 }

 //-------------end of code for ExceptionCache--------------

 int nmethod::total_size() const {

   return

     consts_size()        +

     insts_size()         +

     stub_size()          +

     scopes_data_size()   +

     scopes_pcs_size()    +

     handler_table_size() +

     nul_chk_table_size();

 }

 const char* nmethod::compile_kind() const {

   if (is_osr_method())     return "osr";

   if (method() != NULL && is_native_method())  return "c2n";

   return NULL;

 }

 // Fill in default values for various flag fields

 void nmethod::init_defaults() {

   _state                      = alive;

   _marked_for_reclamation     = 0;

   _has_flushed_dependencies   = 0;

   _speculatively_disconnected = 0;

   _has_unsafe_access          = 0;

   _has_method_handle_invokes  = 0;

   _lazy_critical_native       = 0;

   _has_wide_vectors           = 0;

   _marked_for_deoptimization  = 0;

   _lock_count                 = 0;

   _stack_traversal_mark       = 0;

   _unload_reported            = false;           // jvmti state

 #ifdef ASSERT

   _oops_are_stale             = false;

 #endif

   _oops_do_mark_link       = NULL;

   _jmethod_id              = NULL;

   _osr_link                = NULL;

   _scavenge_root_link      = NULL;

   _scavenge_root_state     = 0;

   _saved_nmethod_link      = NULL;

   _compiler                = NULL;

 #ifdef HAVE_DTRACE_H

   _trap_offset             = 0;

 #endif // def HAVE_DTRACE_H

 }

 nmethod* nmethod::new_native_nmethod(methodHandle method,

   int compile_id,

   CodeBuffer *code_buffer,

   int vep_offset,

   int frame_complete,

   int frame_size,

   ByteSize basic_lock_owner_sp_offset,

   ByteSize basic_lock_sp_offset,

   OopMapSet* oop_maps) {

   code_buffer->finalize_oop_references(method);

   // create nmethod

   nmethod* nm = NULL;

   {

     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

     int native_nmethod_size = allocation_size(code_buffer, sizeof(nmethod));

     CodeOffsets offsets;

     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);

     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);

     nm = new (native_nmethod_size) nmethod(method(), native_nmethod_size,

                                             compile_id, &offsets,

                                             code_buffer, frame_size,

                                             basic_lock_owner_sp_offset,

                                             basic_lock_sp_offset, oop_maps);

     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_native_nmethod(nm));

     if (PrintAssembly && nm != NULL) {

       Disassembler::decode(nm);

     }

   }

   // verify nmethod

   debug_only(if (nm) nm->verify();) // might block

   if (nm != NULL) {

     nm->log_new_nmethod();

   }

   return nm;

 }

 #ifdef HAVE_DTRACE_H

 nmethod* nmethod::new_dtrace_nmethod(methodHandle method,

                                      CodeBuffer *code_buffer,

                                      int vep_offset,

                                      int trap_offset,

                                      int frame_complete,

                                      int frame_size) {

   code_buffer->finalize_oop_references(method);

   // create nmethod

   nmethod* nm = NULL;

   {

     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

     int nmethod_size = allocation_size(code_buffer, sizeof(nmethod));

     CodeOffsets offsets;

     offsets.set_value(CodeOffsets::Verified_Entry, vep_offset);

     offsets.set_value(CodeOffsets::Dtrace_trap, trap_offset);

     offsets.set_value(CodeOffsets::Frame_Complete, frame_complete);

     nm = new (nmethod_size) nmethod(method(), nmethod_size,

                                     &offsets, code_buffer, frame_size);

     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));

     if (PrintAssembly && nm != NULL) {

       Disassembler::decode(nm);

     }

   }

   // verify nmethod

   debug_only(if (nm) nm->verify();) // might block

   if (nm != NULL) {

     nm->log_new_nmethod();

   }

   return nm;

 }

 #endif // def HAVE_DTRACE_H

 nmethod* nmethod::new_nmethod(methodHandle method,

   int compile_id,

   int entry_bci,

   CodeOffsets* offsets,

   int orig_pc_offset,

   DebugInformationRecorder* debug_info,

   Dependencies* dependencies,

   CodeBuffer* code_buffer, int frame_size,

   OopMapSet* oop_maps,

   ExceptionHandlerTable* handler_table,

   ImplicitExceptionTable* nul_chk_table,

   AbstractCompiler* compiler,

   int comp_level

 )

 {

   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");

   code_buffer->finalize_oop_references(method);

   // create nmethod

   nmethod* nm = NULL;

   { MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

     int nmethod_size =

       allocation_size(code_buffer, sizeof(nmethod))

       + adjust_pcs_size(debug_info->pcs_size())

       + round_to(dependencies->size_in_bytes() , oopSize)

       + round_to(handler_table->size_in_bytes(), oopSize)

       + round_to(nul_chk_table->size_in_bytes(), oopSize)

       + round_to(debug_info->data_size()       , oopSize);

     nm = new (nmethod_size)

     nmethod(method(), nmethod_size, compile_id, entry_bci, offsets,

             orig_pc_offset, debug_info, dependencies, code_buffer, frame_size,

             oop_maps,

             handler_table,

             nul_chk_table,

             compiler,

             comp_level);

     if (nm != NULL) {

       // To make dependency checking during class loading fast, record

       // the nmethod dependencies in the classes it is dependent on.

       // This allows the dependency checking code to simply walk the

       // class hierarchy above the loaded class, checking only nmethods

       // which are dependent on those classes.  The slow way is to

       // check every nmethod for dependencies which makes it linear in

       // the number of methods compiled.  For applications with a lot

       // classes the slow way is too slow.

       for (Dependencies::DepStream deps(nm); deps.next(); ) {

         Klass* klass = deps.context_type();

         if (klass == NULL) {

           continue;  // ignore things like evol_method

         }

         // record this nmethod as dependent on this klass

         InstanceKlass::cast(klass)->add_dependent_nmethod(nm);

       }

     }

     NOT_PRODUCT(if (nm != NULL)  nmethod_stats.note_nmethod(nm));

     if (PrintAssembly && nm != NULL) {

       Disassembler::decode(nm);

     }

   }

   // verify nmethod

   debug_only(if (nm) nm->verify();) // might block

   if (nm != NULL) {

     nm->log_new_nmethod();

   }

   // done

   return nm;

 }

 // For native wrappers

 nmethod::nmethod(

   Method* method,

   int nmethod_size,

   int compile_id,

   CodeOffsets* offsets,

   CodeBuffer* code_buffer,

   int frame_size,

   ByteSize basic_lock_owner_sp_offset,

   ByteSize basic_lock_sp_offset,

   OopMapSet* oop_maps )

   : CodeBlob("native nmethod", code_buffer, sizeof(nmethod),

              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),

   _native_receiver_sp_offset(basic_lock_owner_sp_offset),

   _native_basic_lock_sp_offset(basic_lock_sp_offset)

 {

   {

     debug_only(No_Safepoint_Verifier nsv;)

     assert_locked_or_safepoint(CodeCache_lock);

     init_defaults();

     _method                  = method;

     _entry_bci               = InvocationEntryBci;

     // We have no exception handler or deopt handler make the

     // values something that will never match a pc like the nmethod vtable entry

     _exception_offset        = 0;

     _deoptimize_offset       = 0;

     _deoptimize_mh_offset    = 0;

     _orig_pc_offset          = 0;

     _consts_offset           = data_offset();

     _stub_offset             = data_offset();

     _oops_offset             = data_offset();

     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);

     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);

     _scopes_pcs_offset       = _scopes_data_offset;

     _dependencies_offset     = _scopes_pcs_offset;

     _handler_table_offset    = _dependencies_offset;

     _nul_chk_table_offset    = _handler_table_offset;

     _nmethod_end_offset      = _nul_chk_table_offset;

     _compile_id              = compile_id;

     _comp_level              = CompLevel_none;

     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);

     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);

     _osr_entry_point         = NULL;

     _exception_cache         = NULL;

     _pc_desc_cache.reset_to(NULL);

     code_buffer->copy_values_to(this);

     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {

       CodeCache::add_scavenge_root_nmethod(this);

       Universe::heap()->register_nmethod(this);

     }

     debug_only(verify_scavenge_root_oops());

     CodeCache::commit(this);

   }

   if (PrintNativeNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {

     ttyLocker ttyl;  // keep the following output all in one block

     // This output goes directly to the tty, not the compiler log.

     // To enable tools to match it up with the compilation activity,

     // be sure to tag this tty output with the compile ID.

     if (xtty != NULL) {

       xtty->begin_head("print_native_nmethod");

       xtty->method(_method);

       xtty->stamp();

       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);

     }

     // print the header part first

     print();

     // then print the requested information

     if (PrintNativeNMethods) {

       print_code();

       if (oop_maps != NULL) {

         oop_maps->print();

       }

     }

     if (PrintRelocations) {

       print_relocations();

     }

     if (xtty != NULL) {

       xtty->tail("print_native_nmethod");

     }

   }

 }

 // For dtrace wrappers

 #ifdef HAVE_DTRACE_H

 nmethod::nmethod(

   Method* method,

   int nmethod_size,

   CodeOffsets* offsets,

   CodeBuffer* code_buffer,

   int frame_size)

   : CodeBlob("dtrace nmethod", code_buffer, sizeof(nmethod),

              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, NULL),

   _native_receiver_sp_offset(in_ByteSize(-1)),

   _native_basic_lock_sp_offset(in_ByteSize(-1))

 {

   {

     debug_only(No_Safepoint_Verifier nsv;)

     assert_locked_or_safepoint(CodeCache_lock);

     init_defaults();

     _method                  = method;

     _entry_bci               = InvocationEntryBci;

     // We have no exception handler or deopt handler make the

     // values something that will never match a pc like the nmethod vtable entry

     _exception_offset        = 0;

     _deoptimize_offset       = 0;

     _deoptimize_mh_offset    = 0;

     _unwind_handler_offset   = -1;

     _trap_offset             = offsets->value(CodeOffsets::Dtrace_trap);

     _orig_pc_offset          = 0;

     _consts_offset           = data_offset();

     _stub_offset             = data_offset();

     _oops_offset             = data_offset();

     _metadata_offset         = _oops_offset         + round_to(code_buffer->total_oop_size(), oopSize);

     _scopes_data_offset      = _metadata_offset     + round_to(code_buffer->total_metadata_size(), wordSize);

     _scopes_pcs_offset       = _scopes_data_offset;

     _dependencies_offset     = _scopes_pcs_offset;

     _handler_table_offset    = _dependencies_offset;

     _nul_chk_table_offset    = _handler_table_offset;

     _nmethod_end_offset      = _nul_chk_table_offset;

     _compile_id              = 0;  // default

     _comp_level              = CompLevel_none;

     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);

     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);

     _osr_entry_point         = NULL;

     _exception_cache         = NULL;

     _pc_desc_cache.reset_to(NULL);

     code_buffer->copy_values_to(this);

     debug_only(verify_scavenge_root_oops());

     CodeCache::commit(this);

   }

   if (PrintNMethods || PrintDebugInfo || PrintRelocations || PrintDependencies) {

     ttyLocker ttyl;  // keep the following output all in one block

     // This output goes directly to the tty, not the compiler log.

     // To enable tools to match it up with the compilation activity,

     // be sure to tag this tty output with the compile ID.

     if (xtty != NULL) {

       xtty->begin_head("print_dtrace_nmethod");

       xtty->method(_method);

       xtty->stamp();

       xtty->end_head(" address='" INTPTR_FORMAT "'", (intptr_t) this);

     }

     // print the header part first

     print();

     // then print the requested information

     if (PrintNMethods) {

       print_code();

     }

     if (PrintRelocations) {

       print_relocations();

     }

     if (xtty != NULL) {

       xtty->tail("print_dtrace_nmethod");

     }

   }

 }

 #endif // def HAVE_DTRACE_H

 void* nmethod::operator new(size_t size, int nmethod_size) throw() {

   // Not critical, may return null if there is too little continuous memory

   return CodeCache::allocate(nmethod_size);

 }

 nmethod::nmethod(

   Method* method,

   int nmethod_size,

   int compile_id,

   int entry_bci,

   CodeOffsets* offsets,

   int orig_pc_offset,

   DebugInformationRecorder* debug_info,

   Dependencies* dependencies,

   CodeBuffer *code_buffer,

   int frame_size,

   OopMapSet* oop_maps,

   ExceptionHandlerTable* handler_table,

   ImplicitExceptionTable* nul_chk_table,

   AbstractCompiler* compiler,

   int comp_level

   )

   : CodeBlob("nmethod", code_buffer, sizeof(nmethod),

              nmethod_size, offsets->value(CodeOffsets::Frame_Complete), frame_size, oop_maps),

   _native_receiver_sp_offset(in_ByteSize(-1)),

   _native_basic_lock_sp_offset(in_ByteSize(-1))

 {

   assert(debug_info->oop_recorder() == code_buffer->oop_recorder(), "shared OR");

   {

     debug_only(No_Safepoint_Verifier nsv;)

     assert_locked_or_safepoint(CodeCache_lock);

     init_defaults();

     _method                  = method;

     _entry_bci               = entry_bci;

     _compile_id              = compile_id;

     _comp_level              = comp_level;

     _compiler                = compiler;

     _orig_pc_offset          = orig_pc_offset;

     // Section offsets

     _consts_offset           = content_offset()      + code_buffer->total_offset_of(code_buffer->consts());

     _stub_offset             = content_offset()      + code_buffer->total_offset_of(code_buffer->stubs());

     // Exception handler and deopt handler are in the stub section

     assert(offsets->value(CodeOffsets::Exceptions) != -1, "must be set");

     assert(offsets->value(CodeOffsets::Deopt     ) != -1, "must be set");

     _exception_offset        = _stub_offset          + offsets->value(CodeOffsets::Exceptions);

     _deoptimize_offset       = _stub_offset          + offsets->value(CodeOffsets::Deopt);

     if (offsets->value(CodeOffsets::DeoptMH) != -1) {

       _deoptimize_mh_offset  = _stub_offset          + offsets->value(CodeOffsets::DeoptMH);

     } else {

       _deoptimize_mh_offset  = -1;

     }

     if (offsets->value(CodeOffsets::UnwindHandler) != -1) {

       _unwind_handler_offset = code_offset()         + offsets->value(CodeOffsets::UnwindHandler);

     } else {

       _unwind_handler_offset = -1;

     }

     _oops_offset             = data_offset();

     _metadata_offset         = _oops_offset          + round_to(code_buffer->total_oop_size(), oopSize);

     _scopes_data_offset      = _metadata_offset      + round_to(code_buffer->total_metadata_size(), wordSize);

     _scopes_pcs_offset       = _scopes_data_offset   + round_to(debug_info->data_size       (), oopSize);

     _dependencies_offset     = _scopes_pcs_offset    + adjust_pcs_size(debug_info->pcs_size());

     _handler_table_offset    = _dependencies_offset  + round_to(dependencies->size_in_bytes (), oopSize);

     _nul_chk_table_offset    = _handler_table_offset + round_to(handler_table->size_in_bytes(), oopSize);

     _nmethod_end_offset      = _nul_chk_table_offset + round_to(nul_chk_table->size_in_bytes(), oopSize);

     _entry_point             = code_begin()          + offsets->value(CodeOffsets::Entry);

     _verified_entry_point    = code_begin()          + offsets->value(CodeOffsets::Verified_Entry);

     _osr_entry_point         = code_begin()          + offsets->value(CodeOffsets::OSR_Entry);

     _exception_cache         = NULL;

     _pc_desc_cache.reset_to(scopes_pcs_begin());

     // Copy contents of ScopeDescRecorder to nmethod

     code_buffer->copy_values_to(this);

     debug_info->copy_to(this);

     dependencies->copy_to(this);

     if (ScavengeRootsInCode && detect_scavenge_root_oops()) {

       CodeCache::add_scavenge_root_nmethod(this);

       Universe::heap()->register_nmethod(this);

     }

     debug_only(verify_scavenge_root_oops());

     CodeCache::commit(this);

     // Copy contents of ExceptionHandlerTable to nmethod

     handler_table->copy_to(this);

     nul_chk_table->copy_to(this);

     // we use the information of entry points to find out if a method is

     // static or non static

     assert(compiler->is_c2() ||

            _method->is_static() == (entry_point() == _verified_entry_point),

            " entry points must be same for static methods and vice versa");

   }

   bool printnmethods = PrintNMethods

     || CompilerOracle::should_print(_method)

     || CompilerOracle::has_option_string(_method, "PrintNMethods");

   if (printnmethods || PrintDebugInfo || PrintRelocations || PrintDependencies || PrintExceptionHandlers) {

     print_nmethod(printnmethods);

   }

 }

 // Print a short set of xml attributes to identify this nmethod.  The

 // output should be embedded in some other element.

 void nmethod::log_identity(xmlStream* log) const {

   log->print(" compile_id='%d'", compile_id());

   const char* nm_kind = compile_kind();

   if (nm_kind != NULL)  log->print(" compile_kind='%s'", nm_kind);

   if (compiler() != NULL) {

     log->print(" compiler='%s'", compiler()->name());

   }

   if (TieredCompilation) {

     log->print(" level='%d'", comp_level());

   }

 }

 #define LOG_OFFSET(log, name)                    \

   if ((intptr_t)name##_end() - (intptr_t)name##_begin()) \

     log->print(" " XSTR(name) "_offset='%d'"    , \

                (intptr_t)name##_begin() - (intptr_t)this)

 void nmethod::log_new_nmethod() const {

   if (LogCompilation && xtty != NULL) {

     ttyLocker ttyl;

     HandleMark hm;

     xtty->begin_elem("nmethod");

     log_identity(xtty);

     xtty->print(" entry='" INTPTR_FORMAT "' size='%d'", code_begin(), size());

     xtty->print(" address='" INTPTR_FORMAT "'", (intptr_t) this);

     LOG_OFFSET(xtty, relocation);

     LOG_OFFSET(xtty, consts);

     LOG_OFFSET(xtty, insts);

     LOG_OFFSET(xtty, stub);

     LOG_OFFSET(xtty, scopes_data);

     LOG_OFFSET(xtty, scopes_pcs);

     LOG_OFFSET(xtty, dependencies);

     LOG_OFFSET(xtty, handler_table);

     LOG_OFFSET(xtty, nul_chk_table);

     LOG_OFFSET(xtty, oops);

     xtty->method(method());

     xtty->stamp();

     xtty->end_elem();

   }

 }

 #undef LOG_OFFSET

 // Print out more verbose output usually for a newly created nmethod.

 void nmethod::print_on(outputStream* st, const char* msg) const {

   if (st != NULL) {

     ttyLocker ttyl;

     if (WizardMode) {

       CompileTask::print_compilation(st, this, msg, /*short_form:*/ true);

       st->print_cr(" (" INTPTR_FORMAT ")", this);

     } else {

       CompileTask::print_compilation(st, this, msg, /*short_form:*/ false);

     }

   }

 }

 void nmethod::print_nmethod(bool printmethod) {

   ttyLocker ttyl;  // keep the following output all in one block

   if (xtty != NULL) {

     xtty->begin_head("print_nmethod");

     xtty->stamp();

     xtty->end_head();

   }

   // print the header part first

   print();

   // then print the requested information

   if (printmethod) {

     print_code();

     print_pcs();

     if (oop_maps()) {

       oop_maps()->print();

     }

   }

   if (PrintDebugInfo) {

     print_scopes();

   }

   if (PrintRelocations) {

     print_relocations();

   }

   if (PrintDependencies) {

     print_dependencies();

   }

   if (PrintExceptionHandlers) {

     print_handler_table();

     print_nul_chk_table();

   }

   if (xtty != NULL) {

     xtty->tail("print_nmethod");

   }

 }

 // Promote one word from an assembly-time handle to a live embedded oop.

 inline void nmethod::initialize_immediate_oop(oop* dest, jobject handle) {

   if (handle == NULL ||

       // As a special case, IC oops are initialized to 1 or -1.

       handle == (jobject) Universe::non_oop_word()) {

     (*dest) = (oop) handle;

   } else {

     (*dest) = JNIHandles::resolve_non_null(handle);

   }

 }

 // Have to have the same name because it's called by a template

 void nmethod::copy_values(GrowableArray<jobject>* array) {

   int length = array->length();

   assert((address)(oops_begin() + length) <= (address)oops_end(), "oops big enough");

   oop* dest = oops_begin();

   for (int index = 0 ; index < length; index++) {

     initialize_immediate_oop(&dest[index], array->at(index));

   }

   // Now we can fix up all the oops in the code.  We need to do this

   // in the code because the assembler uses jobjects as placeholders.

   // The code and relocations have already been initialized by the

   // CodeBlob constructor, so it is valid even at this early point to

   // iterate over relocations and patch the code.

   fix_oop_relocations(NULL, NULL, /*initialize_immediates=*/ true);

 }

 void nmethod::copy_values(GrowableArray<Metadata*>* array) {

   int length = array->length();

   assert((address)(metadata_begin() + length) <= (address)metadata_end(), "big enough");

   Metadata** dest = metadata_begin();

   for (int index = 0 ; index < length; index++) {

     dest[index] = array->at(index);

   }

 }

 bool nmethod::is_at_poll_return(address pc) {

   RelocIterator iter(this, pc, pc+1);

   while (iter.next()) {

     if (iter.type() == relocInfo::poll_return_type)

       return true;

   }

   return false;

 }

 bool nmethod::is_at_poll_or_poll_return(address pc) {

   RelocIterator iter(this, pc, pc+1);

   while (iter.next()) {

     relocInfo::relocType t = iter.type();

     if (t == relocInfo::poll_return_type || t == relocInfo::poll_type)

       return true;

   }

   return false;

 }

 void nmethod::fix_oop_relocations(address begin, address end, bool initialize_immediates) {

   // re-patch all oop-bearing instructions, just in case some oops moved

   RelocIterator iter(this, begin, end);

   while (iter.next()) {

     if (iter.type() == relocInfo::oop_type) {

       oop_Relocation* reloc = iter.oop_reloc();

       if (initialize_immediates && reloc->oop_is_immediate()) {

         oop* dest = reloc->oop_addr();

         initialize_immediate_oop(dest, (jobject) *dest);

       }

       // Refresh the oop-related bits of this instruction.

       reloc->fix_oop_relocation();

     } else if (iter.type() == relocInfo::metadata_type) {

       metadata_Relocation* reloc = iter.metadata_reloc();

       reloc->fix_metadata_relocation();

     }

   }

 }

 void nmethod::verify_oop_relocations() {

   // Ensure sure that the code matches the current oop values

   RelocIterator iter(this, NULL, NULL);

   while (iter.next()) {

     if (iter.type() == relocInfo::oop_type) {

       oop_Relocation* reloc = iter.oop_reloc();

       if (!reloc->oop_is_immediate()) {

         reloc->verify_oop_relocation();

       }

     }

   }

 }

 ScopeDesc* nmethod::scope_desc_at(address pc) {

   PcDesc* pd = pc_desc_at(pc);

   guarantee(pd != NULL, "scope must be present");

   return new ScopeDesc(this, pd->scope_decode_offset(),

                        pd->obj_decode_offset(), pd->should_reexecute(),

                        pd->return_oop());

 }

 void nmethod::clear_inline_caches() {

   assert(SafepointSynchronize::is_at_safepoint(), "cleaning of IC's only allowed at safepoint");

   if (is_zombie()) {

     return;

   }

   RelocIterator iter(this);

   while (iter.next()) {

     iter.reloc()->clear_inline_cache();

   }

 }

 void nmethod::cleanup_inline_caches() {

   assert_locked_or_safepoint(CompiledIC_lock);

   // If the method is not entrant or zombie then a JMP is plastered over the

   // first few bytes.  If an oop in the old code was there, that oop

   // should not get GC'd.  Skip the first few bytes of oops on

   // not-entrant methods.

   address low_boundary = verified_entry_point();

   if (!is_in_use()) {

     low_boundary += NativeJump::instruction_size;

     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.

     // This means that the low_boundary is going to be a little too high.

     // This shouldn't matter, since oops of non-entrant methods are never used.

     // In fact, why are we bothering to look at oops in a non-entrant method??

   }

   // Find all calls in an nmethod, and clear the ones that points to zombie methods

   ResourceMark rm;

   RelocIterator iter(this, low_boundary);

   while(iter.next()) {

     switch(iter.type()) {

       case relocInfo::virtual_call_type:

       case relocInfo::opt_virtual_call_type: {

         CompiledIC *ic = CompiledIC_at(iter.reloc());

         // Ok, to lookup references to zombies here

         CodeBlob *cb = CodeCache::find_blob_unsafe(ic->ic_destination());

         if( cb != NULL && cb->is_nmethod() ) {

           nmethod* nm = (nmethod*)cb;

           // Clean inline caches pointing to both zombie and not_entrant methods

           if (!nm->is_in_use() || (nm->method()->code() != nm)) ic->set_to_clean();

         }

         break;

       }

       case relocInfo::static_call_type: {

         CompiledStaticCall *csc = compiledStaticCall_at(iter.reloc());

         CodeBlob *cb = CodeCache::find_blob_unsafe(csc->destination());

         if( cb != NULL && cb->is_nmethod() ) {

           nmethod* nm = (nmethod*)cb;

           // Clean inline caches pointing to both zombie and not_entrant methods

           if (!nm->is_in_use() || (nm->method()->code() != nm)) csc->set_to_clean();

         }

         break;

       }

     }

   }

 }

 // This is a private interface with the sweeper.

 void nmethod::mark_as_seen_on_stack() {

   assert(is_not_entrant(), "must be a non-entrant method");

   // Set the traversal mark to ensure that the sweeper does 2

   // cleaning passes before moving to zombie.

   set_stack_traversal_mark(NMethodSweeper::traversal_count());

 }

 // Tell if a non-entrant method can be converted to a zombie (i.e.,

 // there are no activations on the stack, not in use by the VM,

 // and not in use by the ServiceThread)

 bool nmethod::can_not_entrant_be_converted() {

   assert(is_not_entrant(), "must be a non-entrant method");

   // Since the nmethod sweeper only does partial sweep the sweeper's traversal

   // count can be greater than the stack traversal count before it hits the

   // nmethod for the second time.

   return stack_traversal_mark()+1 < NMethodSweeper::traversal_count() &&

          !is_locked_by_vm();

 }

 void nmethod::inc_decompile_count() {

   if (!is_compiled_by_c2()) return;

   // Could be gated by ProfileTraps, but do not bother...

   Method* m = method();

   if (m == NULL)  return;

   MethodData* mdo = m->method_data();

   if (mdo == NULL)  return;

   // There is a benign race here.  See comments in methodData.hpp.

   mdo->inc_decompile_count();

 }

 void nmethod::make_unloaded(BoolObjectClosure* is_alive, oop cause) {

   post_compiled_method_unload();

   // Since this nmethod is being unloaded, make sure that dependencies

   // recorded in instanceKlasses get flushed and pass non-NULL closure to

   // indicate that this work is being done during a GC.

   assert(Universe::heap()->is_gc_active(), "should only be called during gc");

   assert(is_alive != NULL, "Should be non-NULL");

   // A non-NULL is_alive closure indicates that this is being called during GC.

   flush_dependencies(is_alive);

   // Break cycle between nmethod & method

   if (TraceClassUnloading && WizardMode) {

     tty->print_cr("[Class unloading: Making nmethod " INTPTR_FORMAT

                   " unloadable], Method*(" INTPTR_FORMAT

                   "), cause(" INTPTR_FORMAT ")",

                   this, (address)_method, (address)cause);

     if (!Universe::heap()->is_gc_active())

       cause->klass()->print();

   }

   // Unlink the osr method, so we do not look this up again

   if (is_osr_method()) {

     invalidate_osr_method();

   }

   // If _method is already NULL the Method* is about to be unloaded,

   // so we don't have to break the cycle. Note that it is possible to

   // have the Method* live here, in case we unload the nmethod because

   // it is pointing to some oop (other than the Method*) being unloaded.

   if (_method != NULL) {

     // OSR methods point to the Method*, but the Method* does not

     // point back!

     if (_method->code() == this) {

       _method->clear_code(); // Break a cycle

     }

     _method = NULL;            // Clear the method of this dead nmethod

   }

   // Make the class unloaded - i.e., change state and notify sweeper

   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");

   if (is_in_use()) {

     // Transitioning directly from live to unloaded -- so

     // we need to force a cache clean-up; remember this

     // for later on.

     CodeCache::set_needs_cache_clean(true);

   }

   _state = unloaded;

   // Log the unloading.

   log_state_change();

   // The Method* is gone at this point

   assert(_method == NULL, "Tautology");

   set_osr_link(NULL);

   //set_scavenge_root_link(NULL); // done by prune_scavenge_root_nmethods

   NMethodSweeper::notify(this);

 }

 void nmethod::invalidate_osr_method() {

   assert(_entry_bci != InvocationEntryBci, "wrong kind of nmethod");

   // Remove from list of active nmethods

   if (method() != NULL)

     method()->method_holder()->remove_osr_nmethod(this);

   // Set entry as invalid

   _entry_bci = InvalidOSREntryBci;

 }

 void nmethod::log_state_change() const {

   if (LogCompilation) {

     if (xtty != NULL) {

       ttyLocker ttyl;  // keep the following output all in one block

       if (_state == unloaded) {

         xtty->begin_elem("make_unloaded thread='" UINTX_FORMAT "'",

                          os::current_thread_id());

       } else {

         xtty->begin_elem("make_not_entrant thread='" UINTX_FORMAT "'%s",

                          os::current_thread_id(),

                          (_state == zombie ? " zombie='1'" : ""));

       }

       log_identity(xtty);

       xtty->stamp();

       xtty->end_elem();

     }

   }

   if (PrintCompilation && _state != unloaded) {

     print_on(tty, _state == zombie ? "made zombie" : "made not entrant");

   }

 }

 // Common functionality for both make_not_entrant and make_zombie

 bool nmethod::make_not_entrant_or_zombie(unsigned int state) {

   assert(state == zombie || state == not_entrant, "must be zombie or not_entrant");

   assert(!is_zombie(), "should not already be a zombie");

   // Make sure neither the nmethod nor the method is flushed in case of a safepoint in code below.

   nmethodLocker nml(this);

   methodHandle the_method(method());

   No_Safepoint_Verifier nsv;

   // during patching, depending on the nmethod state we must notify the GC that

   // code has been unloaded, unregistering it. We cannot do this right while

   // holding the Patching_lock because we need to use the CodeCache_lock. This

   // would be prone to deadlocks.

   // This flag is used to remember whether we need to later lock and unregister.

   bool nmethod_needs_unregister = false;

   {

     // invalidate osr nmethod before acquiring the patching lock since

     // they both acquire leaf locks and we don't want a deadlock.

     // This logic is equivalent to the logic below for patching the

     // verified entry point of regular methods.

     if (is_osr_method()) {

       // this effectively makes the osr nmethod not entrant

       invalidate_osr_method();

     }

     // Enter critical section.  Does not block for safepoint.

     MutexLockerEx pl(Patching_lock, Mutex::_no_safepoint_check_flag);

     if (_state == state) {

       // another thread already performed this transition so nothing

       // to do, but return false to indicate this.

       return false;

     }

     // The caller can be calling the method statically or through an inline

     // cache call.

     if (!is_osr_method() && !is_not_entrant()) {

       NativeJump::patch_verified_entry(entry_point(), verified_entry_point(),

                   SharedRuntime::get_handle_wrong_method_stub());

     }

     if (is_in_use()) {

       // It's a true state change, so mark the method as decompiled.

       // Do it only for transition from alive.

       inc_decompile_count();

     }

     // If the state is becoming a zombie, signal to unregister the nmethod with

     // the heap.

     // This nmethod may have already been unloaded during a full GC.

     if ((state == zombie) && !is_unloaded()) {

       nmethod_needs_unregister = true;

     }

     // Change state

     _state = state;

     // Log the transition once

     log_state_change();

     // Remove nmethod from method.

     // We need to check if both the _code and _from_compiled_code_entry_point

     // refer to this nmethod because there is a race in setting these two fields

     // in Method* as seen in bugid 4947125.

     // If the vep() points to the zombie nmethod, the memory for the nmethod

     // could be flushed and the compiler and vtable stubs could still call

     // through it.

     if (method() != NULL && (method()->code() == this ||

                              method()->from_compiled_entry() == verified_entry_point())) {

       HandleMark hm;

       method()->clear_code();

     }

     if (state == not_entrant) {

       mark_as_seen_on_stack();

     }

   } // leave critical region under Patching_lock

   // When the nmethod becomes zombie it is no longer alive so the

   // dependencies must be flushed.  nmethods in the not_entrant

   // state will be flushed later when the transition to zombie

   // happens or they get unloaded.

   if (state == zombie) {

     {

       // Flushing dependecies must be done before any possible

       // safepoint can sneak in, otherwise the oops used by the

       // dependency logic could have become stale.

       MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);

       if (nmethod_needs_unregister) {

         Universe::heap()->unregister_nmethod(this);

       }

       flush_dependencies(NULL);

     }

     // zombie only - if a JVMTI agent has enabled the CompiledMethodUnload

     // event and it hasn't already been reported for this nmethod then

     // report it now. The event may have been reported earilier if the GC

     // marked it for unloading). JvmtiDeferredEventQueue support means

     // we no longer go to a safepoint here.

     post_compiled_method_unload();

 #ifdef ASSERT

     // It's no longer safe to access the oops section since zombie

     // nmethods aren't scanned for GC.

     _oops_are_stale = true;

 #endif

      // the Method may be reclaimed by class unloading now that the

      // nmethod is in zombie state

     set_method(NULL);

   } else {

     assert(state == not_entrant, "other cases may need to be handled differently");

   }

   if (TraceCreateZombies) {

     tty->print_cr("nmethod <" INTPTR_FORMAT "> code made %s", this, (state == not_entrant) ? "not entrant" : "zombie");

   }

   // Make sweeper aware that there is a zombie method that needs to be removed

   NMethodSweeper::notify(this);

   return true;

 }

 void nmethod::flush() {

   // Note that there are no valid oops in the nmethod anymore.

   assert(is_zombie() || (is_osr_method() && is_unloaded()), "must be a zombie method");

   assert(is_marked_for_reclamation() || (is_osr_method() && is_unloaded()), "must be marked for reclamation");

   assert (!is_locked_by_vm(), "locked methods shouldn't be flushed");

   assert_locked_or_safepoint(CodeCache_lock);

   // completely deallocate this method

   Events::log(JavaThread::current(), "flushing nmethod " INTPTR_FORMAT, this);

   if (PrintMethodFlushing) {

     tty->print_cr("*flushing nmethod %3d/" INTPTR_FORMAT ". Live blobs:" UINT32_FORMAT "/Free CodeCache:" SIZE_FORMAT "Kb",

         _compile_id, this, CodeCache::nof_blobs(), CodeCache::unallocated_capacity()/1024);

   }

   // We need to deallocate any ExceptionCache data.

   // Note that we do not need to grab the nmethod lock for this, it

   // better be thread safe if we're disposing of it!

   ExceptionCache* ec = exception_cache();

   set_exception_cache(NULL);

   while(ec != NULL) {

     ExceptionCache* next = ec->next();

     delete ec;

     ec = next;

   }

   if (on_scavenge_root_list()) {

     CodeCache::drop_scavenge_root_nmethod(this);

   }

   if (is_speculatively_disconnected()) {

     CodeCache::remove_saved_code(this);

   }

 #ifdef SHARK

   ((SharkCompiler *) compiler())->free_compiled_method(insts_begin());

 #endif // SHARK

   ((CodeBlob*)(this))->flush();

   CodeCache::free(this);

 }

 //

 // Notify all classes this nmethod is dependent on that it is no

 // longer dependent. This should only be called in two situations.

 // First, when a nmethod transitions to a zombie all dependents need

 // to be clear.  Since zombification happens at a safepoint there's no

 // synchronization issues.  The second place is a little more tricky.

 // During phase 1 of mark sweep class unloading may happen and as a

 // result some nmethods may get unloaded.  In this case the flushing

 // of dependencies must happen during phase 1 since after GC any

 // dependencies in the unloaded nmethod won't be updated, so

 // traversing the dependency information in unsafe.  In that case this

 // function is called with a non-NULL argument and this function only

 // notifies instanceKlasses that are reachable

 void nmethod::flush_dependencies(BoolObjectClosure* is_alive) {

   assert_locked_or_safepoint(CodeCache_lock);

   assert(Universe::heap()->is_gc_active() == (is_alive != NULL),

   "is_alive is non-NULL if and only if we are called during GC");

   if (!has_flushed_dependencies()) {

     set_has_flushed_dependencies();

     for (Dependencies::DepStream deps(this); deps.next(); ) {

       Klass* klass = deps.context_type();

       if (klass == NULL)  continue;  // ignore things like evol_method

       // During GC the is_alive closure is non-NULL, and is used to

       // determine liveness of dependees that need to be updated.

       if (is_alive == NULL || klass->is_loader_alive(is_alive)) {

         InstanceKlass::cast(klass)->remove_dependent_nmethod(this);

       }

     }

   }

 }

 // If this oop is not live, the nmethod can be unloaded.

 bool nmethod::can_unload(BoolObjectClosure* is_alive, oop* root, bool unloading_occurred) {

   assert(root != NULL, "just checking");

   oop obj = *root;

   if (obj == NULL || is_alive->do_object_b(obj)) {

       return false;

   }

   // If ScavengeRootsInCode is true, an nmethod might be unloaded

   // simply because one of its constant oops has gone dead.

   // No actual classes need to be unloaded in order for this to occur.

   assert(unloading_occurred || ScavengeRootsInCode, "Inconsistency in unloading");

   make_unloaded(is_alive, obj);

   return true;

 }

 // ------------------------------------------------------------------

 // post_compiled_method_load_event

 // new method for install_code() path

 // Transfer information from compilation to jvmti

 void nmethod::post_compiled_method_load_event() {

   Method* moop = method();

 #ifndef USDT2

   HS_DTRACE_PROBE8(hotspot, compiled__method__load,

       moop->klass_name()->bytes(),

       moop->klass_name()->utf8_length(),

       moop->name()->bytes(),

       moop->name()->utf8_length(),

       moop->signature()->bytes(),

       moop->signature()->utf8_length(),

       insts_begin(), insts_size());

 #else /* USDT2 */

   HOTSPOT_COMPILED_METHOD_LOAD(

       (char *) moop->klass_name()->bytes(),

       moop->klass_name()->utf8_length(),

       (char *) moop->name()->bytes(),

       moop->name()->utf8_length(),

       (char *) moop->signature()->bytes(),

       moop->signature()->utf8_length(),

       insts_begin(), insts_size());

 #endif /* USDT2 */

   if (JvmtiExport::should_post_compiled_method_load() ||

       JvmtiExport::should_post_compiled_method_unload()) {

     get_and_cache_jmethod_id();

   }

   if (JvmtiExport::should_post_compiled_method_load()) {

     // Let the Service thread (which is a real Java thread) post the event

     MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);

     JvmtiDeferredEventQueue::enqueue(

       JvmtiDeferredEvent::compiled_method_load_event(this));

   }

 }

 jmethodID nmethod::get_and_cache_jmethod_id() {

   if (_jmethod_id == NULL) {

     // Cache the jmethod_id since it can no longer be looked up once the

     // method itself has been marked for unloading.

     _jmethod_id = method()->jmethod_id();

   }

   return _jmethod_id;

 }

 void nmethod::post_compiled_method_unload() {

   if (unload_reported()) {

     // During unloading we transition to unloaded and then to zombie

     // and the unloading is reported during the first transition.

     return;

   }

   assert(_method != NULL && !is_unloaded(), "just checking");

   DTRACE_METHOD_UNLOAD_PROBE(method());

   // If a JVMTI agent has enabled the CompiledMethodUnload event then

   // post the event. Sometime later this nmethod will be made a zombie

   // by the sweeper but the Method* will not be valid at that point.

   // If the _jmethod_id is null then no load event was ever requested

   // so don't bother posting the unload.  The main reason for this is

   // that the jmethodID is a weak reference to the Method* so if

   // it's being unloaded there's no way to look it up since the weak

   // ref will have been cleared.

   if (_jmethod_id != NULL && JvmtiExport::should_post_compiled_method_unload()) {

     assert(!unload_reported(), "already unloaded");

     JvmtiDeferredEvent event =

       JvmtiDeferredEvent::compiled_method_unload_event(this,

           _jmethod_id, insts_begin());

     if (SafepointSynchronize::is_at_safepoint()) {

       // Don't want to take the queueing lock. Add it as pending and

       // it will get enqueued later.

       JvmtiDeferredEventQueue::add_pending_event(event);

     } else {

       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);

       JvmtiDeferredEventQueue::enqueue(event);

     }

   }

   // The JVMTI CompiledMethodUnload event can be enabled or disabled at

   // any time. As the nmethod is being unloaded now we mark it has

   // having the unload event reported - this will ensure that we don't

   // attempt to report the event in the unlikely scenario where the

   // event is enabled at the time the nmethod is made a zombie.

   set_unload_reported();

 }

 // This is called at the end of the strong tracing/marking phase of a

 // GC to unload an nmethod if it contains otherwise unreachable

 // oops.

 void nmethod::do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred) {

   // Make sure the oop's ready to receive visitors

   assert(!is_zombie() && !is_unloaded(),

          "should not call follow on zombie or unloaded nmethod");

   // If the method is not entrant then a JMP is plastered over the

   // first few bytes.  If an oop in the old code was there, that oop

   // should not get GC'd.  Skip the first few bytes of oops on

   // not-entrant methods.

   address low_boundary = verified_entry_point();

   if (is_not_entrant()) {

     low_boundary += NativeJump::instruction_size;

     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.

     // (See comment above.)

   }

   // The RedefineClasses() API can cause the class unloading invariant

   // to no longer be true. See jvmtiExport.hpp for details.

   // Also, leave a debugging breadcrumb in local flag.

   bool a_class_was_redefined = JvmtiExport::has_redefined_a_class();

   if (a_class_was_redefined) {

     // This set of the unloading_occurred flag is done before the

     // call to post_compiled_method_unload() so that the unloading

     // of this nmethod is reported.

     unloading_occurred = true;

   }

   // Exception cache

   ExceptionCache* ec = exception_cache();

   while (ec != NULL) {

     Klass* ex_klass = ec->exception_type();

     ExceptionCache* next_ec = ec->next();

     if (ex_klass != NULL && !ex_klass->is_loader_alive(is_alive)) {

       remove_from_exception_cache(ec);

     }

     ec = next_ec;

   }

   // If class unloading occurred we first iterate over all inline caches and

   // clear ICs where the cached oop is referring to an unloaded klass or method.

   // The remaining live cached oops will be traversed in the relocInfo::oop_type

   // iteration below.

   if (unloading_occurred) {

     RelocIterator iter(this, low_boundary);

     while(iter.next()) {

       if (iter.type() == relocInfo::virtual_call_type) {

         CompiledIC *ic = CompiledIC_at(iter.reloc());

         if (ic->is_icholder_call()) {

           // The only exception is compiledICHolder oops which may

           // yet be marked below. (We check this further below).

           CompiledICHolder* cichk_oop = ic->cached_icholder();

           if (cichk_oop->holder_method()->method_holder()->is_loader_alive(is_alive) &&

               cichk_oop->holder_klass()->is_loader_alive(is_alive)) {

               continue;

             }

         } else {

           Metadata* ic_oop = ic->cached_metadata();

           if (ic_oop != NULL) {

             if (ic_oop->is_klass()) {

               if (((Klass*)ic_oop)->is_loader_alive(is_alive)) {

                 continue;

               }

             } else if (ic_oop->is_method()) {

               if (((Method*)ic_oop)->method_holder()->is_loader_alive(is_alive)) {

                 continue;

               }

             } else {

               ShouldNotReachHere();

             }

           }

           }

           ic->set_to_clean();

       }

     }

   }

   // Compiled code

   {

   RelocIterator iter(this, low_boundary);

   while (iter.next()) {

     if (iter.type() == relocInfo::oop_type) {

       oop_Relocation* r = iter.oop_reloc();

       // In this loop, we must only traverse those oops directly embedded in

       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.

       assert(1 == (r->oop_is_immediate()) +

                   (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),

              "oop must be found in exactly one place");

       if (r->oop_is_immediate() && r->oop_value() != NULL) {

         if (can_unload(is_alive, r->oop_addr(), unloading_occurred)) {

           return;

         }

       }

     }

   }

   }

   // Scopes

   for (oop* p = oops_begin(); p < oops_end(); p++) {

     if (*p == Universe::non_oop_word())  continue;  // skip non-oops

     if (can_unload(is_alive, p, unloading_occurred)) {

       return;

     }

   }

   // Ensure that all metadata is still alive

   verify_metadata_loaders(low_boundary, is_alive);

 }

 #ifdef ASSERT

 class CheckClass : AllStatic {

   static BoolObjectClosure* _is_alive;

   // Check class_loader is alive for this bit of metadata.

   static void check_class(Metadata* md) {

     Klass* klass = NULL;

     if (md->is_klass()) {

       klass = ((Klass*)md);

     } else if (md->is_method()) {

       klass = ((Method*)md)->method_holder();

     } else if (md->is_methodData()) {

       klass = ((MethodData*)md)->method()->method_holder();

     } else {

       md->print();

       ShouldNotReachHere();

     }

     assert(klass->is_loader_alive(_is_alive), "must be alive");

   }

  public:

   static void do_check_class(BoolObjectClosure* is_alive, nmethod* nm) {

     assert(SafepointSynchronize::is_at_safepoint(), "this is only ok at safepoint");

     _is_alive = is_alive;

     nm->metadata_do(check_class);

   }

 };

 // This is called during a safepoint so can use static data

 BoolObjectClosure* CheckClass::_is_alive = NULL;

 #endif // ASSERT

 // Processing of oop references should have been sufficient to keep

 // all strong references alive.  Any weak references should have been

 // cleared as well.  Visit all the metadata and ensure that it's

 // really alive.

 void nmethod::verify_metadata_loaders(address low_boundary, BoolObjectClosure* is_alive) {

 #ifdef ASSERT

     RelocIterator iter(this, low_boundary);

     while (iter.next()) {

     // static_stub_Relocations may have dangling references to

     // Method*s so trim them out here.  Otherwise it looks like

     // compiled code is maintaining a link to dead metadata.

     address static_call_addr = NULL;

     if (iter.type() == relocInfo::opt_virtual_call_type) {

       CompiledIC* cic = CompiledIC_at(iter.reloc());

       if (!cic->is_call_to_interpreted()) {

         static_call_addr = iter.addr();

       }

     } else if (iter.type() == relocInfo::static_call_type) {

       CompiledStaticCall* csc = compiledStaticCall_at(iter.reloc());

       if (!csc->is_call_to_interpreted()) {

         static_call_addr = iter.addr();

       }

     }

     if (static_call_addr != NULL) {

       RelocIterator sciter(this, low_boundary);

       while (sciter.next()) {

         if (sciter.type() == relocInfo::static_stub_type &&

             sciter.static_stub_reloc()->static_call() == static_call_addr) {

           sciter.static_stub_reloc()->clear_inline_cache();

         }

       }

     }

   }

   // Check that the metadata embedded in the nmethod is alive

   CheckClass::do_check_class(is_alive, this);

 #endif

 }

 // Iterate over metadata calling this function.   Used by RedefineClasses

 void nmethod::metadata_do(void f(Metadata*)) {

   address low_boundary = verified_entry_point();

   if (is_not_entrant()) {

     low_boundary += NativeJump::instruction_size;

     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.

     // (See comment above.)

   }

   {

     // Visit all immediate references that are embedded in the instruction stream.

     RelocIterator iter(this, low_boundary);

     while (iter.next()) {

       if (iter.type() == relocInfo::metadata_type ) {

         metadata_Relocation* r = iter.metadata_reloc();

         // In this lmetadata, we must only follow those metadatas directly embedded in

         // the code.  Other metadatas (oop_index>0) are seen as part of

         // the metadata section below.

         assert(1 == (r->metadata_is_immediate()) +

                (r->metadata_addr() >= metadata_begin() && r->metadata_addr() < metadata_end()),

                "metadata must be found in exactly one place");

         if (r->metadata_is_immediate() && r->metadata_value() != NULL) {

           Metadata* md = r->metadata_value();

           f(md);

         }

       } else if (iter.type() == relocInfo::virtual_call_type) {

         // Check compiledIC holders associated with this nmethod

         CompiledIC *ic = CompiledIC_at(iter.reloc());

         if (ic->is_icholder_call()) {

           CompiledICHolder* cichk = ic->cached_icholder();

           f(cichk->holder_method());

           f(cichk->holder_klass());

         } else {

           Metadata* ic_oop = ic->cached_metadata();

           if (ic_oop != NULL) {

             f(ic_oop);

           }

         }

       }

     }

   }

   // Visit the metadata section

   for (Metadata** p = metadata_begin(); p < metadata_end(); p++) {

     if (*p == Universe::non_oop_word() || *p == NULL)  continue;  // skip non-oops

     Metadata* md = *p;

     f(md);

   }

   // Call function Method*, not embedded in these other places.

   if (_method != NULL) f(_method);

 }

 void nmethod::oops_do(OopClosure* f, bool allow_zombie) {

   // make sure the oops ready to receive visitors

   assert(allow_zombie || !is_zombie(), "should not call follow on zombie nmethod");

   assert(!is_unloaded(), "should not call follow on unloaded nmethod");

   // If the method is not entrant or zombie then a JMP is plastered over the

   // first few bytes.  If an oop in the old code was there, that oop

   // should not get GC'd.  Skip the first few bytes of oops on

   // not-entrant methods.

   address low_boundary = verified_entry_point();

   if (is_not_entrant()) {

     low_boundary += NativeJump::instruction_size;

     // %%% Note:  On SPARC we patch only a 4-byte trap, not a full NativeJump.

     // (See comment above.)

   }

   RelocIterator iter(this, low_boundary);

   while (iter.next()) {

     if (iter.type() == relocInfo::oop_type ) {

       oop_Relocation* r = iter.oop_reloc();

       // In this loop, we must only follow those oops directly embedded in

       // the code.  Other oops (oop_index>0) are seen as part of scopes_oops.

       assert(1 == (r->oop_is_immediate()) +

                    (r->oop_addr() >= oops_begin() && r->oop_addr() < oops_end()),

              "oop must be found in exactly one place");

       if (r->oop_is_immediate() && r->oop_value() != NULL) {

         f->do_oop(r->oop_addr());

       }

     }

   }

   // Scopes

   // This includes oop constants not inlined in the code stream.

   for (oop* p = oops_begin(); p < oops_end(); p++) {

     if (*p == Universe::non_oop_word())  continue;  // skip non-oops

     f->do_oop(p);

   }

 }

 #define NMETHOD_SENTINEL ((nmethod*)badAddress)

 nmethod* volatile nmethod::_oops_do_mark_nmethods;

 // An nmethod is "marked" if its _mark_link is set non-null.

 // Even if it is the end of the linked list, it will have a non-null link value,

 // as long as it is on the list.

 // This code must be MP safe, because it is used from parallel GC passes.

 bool nmethod::test_set_oops_do_mark() {

   assert(nmethod::oops_do_marking_is_active(), "oops_do_marking_prologue must be called");

   nmethod* observed_mark_link = _oops_do_mark_link;

   if (observed_mark_link == NULL) {

     // Claim this nmethod for this thread to mark.

     observed_mark_link = (nmethod*)

       Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_link, NULL);

     if (observed_mark_link == NULL) {

       // Atomically append this nmethod (now claimed) to the head of the list:

       nmethod* observed_mark_nmethods = _oops_do_mark_nmethods;

       for (;;) {

         nmethod* required_mark_nmethods = observed_mark_nmethods;

         _oops_do_mark_link = required_mark_nmethods;

         observed_mark_nmethods = (nmethod*)

           Atomic::cmpxchg_ptr(this, &_oops_do_mark_nmethods, required_mark_nmethods);

         if (observed_mark_nmethods == required_mark_nmethods)

           break;

       }

       // Mark was clear when we first saw this guy.

       NOT_PRODUCT(if (TraceScavenge)  print_on(tty, "oops_do, mark"));

       return false;

     }

   }

   // On fall through, another racing thread marked this nmethod before we did.

   return true;

 }

 void nmethod::oops_do_marking_prologue() {

   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("[oops_do_marking_prologue"));

   assert(_oops_do_mark_nmethods == NULL, "must not call oops_do_marking_prologue twice in a row");

   // We use cmpxchg_ptr instead of regular assignment here because the user

   // may fork a bunch of threads, and we need them all to see the same state.

   void* observed = Atomic::cmpxchg_ptr(NMETHOD_SENTINEL, &_oops_do_mark_nmethods, NULL);

   guarantee(observed == NULL, "no races in this sequential code");

 }

 void nmethod::oops_do_marking_epilogue() {

   assert(_oops_do_mark_nmethods != NULL, "must not call oops_do_marking_epilogue twice in a row");

   nmethod* cur = _oops_do_mark_nmethods;

   while (cur != NMETHOD_SENTINEL) {

     assert(cur != NULL, "not NULL-terminated");

     nmethod* next = cur->_oops_do_mark_link;

     cur->_oops_do_mark_link = NULL;

     cur->fix_oop_relocations();

     NOT_PRODUCT(if (TraceScavenge)  cur->print_on(tty, "oops_do, unmark"));

     cur = next;

   }

   void* required = _oops_do_mark_nmethods;

   void* observed = Atomic::cmpxchg_ptr(NULL, &_oops_do_mark_nmethods, required);

   guarantee(observed == required, "no races in this sequential code");

   NOT_PRODUCT(if (TraceScavenge)  tty->print_cr("oops_do_marking_epilogue]"));

 }

 class DetectScavengeRoot: public OopClosure {

   bool     _detected_scavenge_root;

 public:

   DetectScavengeRoot() : _detected_scavenge_root(false)

   { NOT_PRODUCT(_print_nm = NULL); }

   bool detected_scavenge_root() { return _detected_scavenge_root; }

   virtual void do_oop(oop* p) {

     if ((*p) != NULL && (*p)->is_scavengable()) {

       NOT_PRODUCT(maybe_print(p));

       _detected_scavenge_root = true;

     }

   }

   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }

 #ifndef PRODUCT

   nmethod* _print_nm;

   void maybe_print(oop* p) {

     if (_print_nm == NULL)  return;

     if (!_detected_scavenge_root)  _print_nm->print_on(tty, "new scavenge root");

     tty->print_cr(""PTR_FORMAT"[offset=%d] detected scavengable oop "PTR_FORMAT" (found at "PTR_FORMAT")",

                   _print_nm, (int)((intptr_t)p - (intptr_t)_print_nm),

                   (void *)(*p), (intptr_t)p);

     (*p)->print();

   }

 #endif //PRODUCT

 };

 bool nmethod::detect_scavenge_root_oops() {

   DetectScavengeRoot detect_scavenge_root;

   NOT_PRODUCT(if (TraceScavenge)  detect_scavenge_root._print_nm = this);

   oops_do(&detect_scavenge_root);

   return detect_scavenge_root.detected_scavenge_root();

 }

 // Method that knows how to preserve outgoing arguments at call. This method must be

 // called with a frame corresponding to a Java invoke

 void nmethod::preserve_callee_argument_oops(frame fr, const RegisterMap *reg_map, OopClosure* f) {

 #ifndef SHARK

   if (!method()->is_native()) {

     SimpleScopeDesc ssd(this, fr.pc());

     Bytecode_invoke call(ssd.method(), ssd.bci());

     bool has_receiver = call.has_receiver();

     bool has_appendix = call.has_appendix();

     Symbol* signature = call.signature();

     fr.oops_compiled_arguments_do(signature, has_receiver, has_appendix, reg_map, f);

   }

 #endif // !SHARK

 }

 oop nmethod::embeddedOop_at(u_char* p) {

   RelocIterator iter(this, p, p + 1);

   while (iter.next())

     if (iter.type() == relocInfo::oop_type) {

       return iter.oop_reloc()->oop_value();

     }

   return NULL;

 }

 inline bool includes(void* p, void* from, void* to) {

   return from <= p && p < to;

 }

 void nmethod::copy_scopes_pcs(PcDesc* pcs, int count) {

   assert(count >= 2, "must be sentinel values, at least");

 #ifdef ASSERT

   // must be sorted and unique; we do a binary search in find_pc_desc()

   int prev_offset = pcs[0].pc_offset();

   assert(prev_offset == PcDesc::lower_offset_limit,

          "must start with a sentinel");

   for (int i = 1; i < count; i++) {

     int this_offset = pcs[i].pc_offset();

     assert(this_offset > prev_offset, "offsets must be sorted");

     prev_offset = this_offset;

   }

   assert(prev_offset == PcDesc::upper_offset_limit,

          "must end with a sentinel");

 #endif //ASSERT

   // Search for MethodHandle invokes and tag the nmethod.

   for (int i = 0; i < count; i++) {

     if (pcs[i].is_method_handle_invoke()) {

       set_has_method_handle_invokes(true);

       break;

     }

   }

   assert(has_method_handle_invokes() == (_deoptimize_mh_offset != -1), "must have deopt mh handler");

   int size = count * sizeof(PcDesc);

   assert(scopes_pcs_size() >= size, "oob");

   memcpy(scopes_pcs_begin(), pcs, size);

   // Adjust the final sentinel downward.

   PcDesc* last_pc = &scopes_pcs_begin()[count-1];

   assert(last_pc->pc_offset() == PcDesc::upper_offset_limit, "sanity");

   last_pc->set_pc_offset(content_size() + 1);

   for (; last_pc + 1 < scopes_pcs_end(); last_pc += 1) {

     // Fill any rounding gaps with copies of the last record.

     last_pc[1] = last_pc[0];

   }

   // The following assert could fail if sizeof(PcDesc) is not

   // an integral multiple of oopSize (the rounding term).

   // If it fails, change the logic to always allocate a multiple

   // of sizeof(PcDesc), and fill unused words with copies of *last_pc.

   assert(last_pc + 1 == scopes_pcs_end(), "must match exactly");

 }

 void nmethod::copy_scopes_data(u_char* buffer, int size) {

   assert(scopes_data_size() >= size, "oob");

   memcpy(scopes_data_begin(), buffer, size);

 }

 #ifdef ASSERT

 static PcDesc* linear_search(nmethod* nm, int pc_offset, bool approximate) {

   PcDesc* lower = nm->scopes_pcs_begin();

   PcDesc* upper = nm->scopes_pcs_end();

   lower += 1; // exclude initial sentinel

   PcDesc* res = NULL;

   for (PcDesc* p = lower; p < upper; p++) {

     NOT_PRODUCT(--nmethod_stats.pc_desc_tests);  // don't count this call to match_desc

     if (match_desc(p, pc_offset, approximate)) {

       if (res == NULL)

         res = p;

       else

         res = (PcDesc*) badAddress;

     }

   }

   return res;

 }

 #endif

 // Finds a PcDesc with real-pc equal to "pc"

 PcDesc* nmethod::find_pc_desc_internal(address pc, bool approximate) {

   address base_address = code_begin();

   if ((pc < base_address) ||

       (pc - base_address) >= (ptrdiff_t) PcDesc::upper_offset_limit) {

     return NULL;  // PC is wildly out of range

   }

   int pc_offset = (int) (pc - base_address);

   // Check the PcDesc cache if it contains the desired PcDesc

   // (This as an almost 100% hit rate.)

   PcDesc* res = _pc_desc_cache.find_pc_desc(pc_offset, approximate);

   if (res != NULL) {

     assert(res == linear_search(this, pc_offset, approximate), "cache ok");

     return res;

   }

   // Fallback algorithm: quasi-linear search for the PcDesc

   // Find the last pc_offset less than the given offset.

   // The successor must be the required match, if there is a match at all.

   // (Use a fixed radix to avoid expensive affine pointer arithmetic.)

   PcDesc* lower = scopes_pcs_begin();

   PcDesc* upper = scopes_pcs_end();

   upper -= 1; // exclude final sentinel

   if (lower >= upper)  return NULL;  // native method; no PcDescs at all

 #define assert_LU_OK \

   /* invariant on lower..upper during the following search: */ \

   assert(lower->pc_offset() <  pc_offset, "sanity"); \

   assert(upper->pc_offset() >= pc_offset, "sanity")

   assert_LU_OK;

   // Use the last successful return as a split point.

   PcDesc* mid = _pc_desc_cache.last_pc_desc();

   NOT_PRODUCT(++nmethod_stats.pc_desc_searches);

   if (mid->pc_offset() < pc_offset) {

     lower = mid;

   } else {

     upper = mid;

   }

   // Take giant steps at first (4096, then 256, then 16, then 1)

   const int LOG2_RADIX = 4 /*smaller steps in debug mode:*/ debug_only(-1);

   const int RADIX = (1 << LOG2_RADIX);

   for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {

     while ((mid = lower + step) < upper) {

       assert_LU_OK;

       NOT_PRODUCT(++nmethod_stats.pc_desc_searches);

       if (mid->pc_offset() < pc_offset) {

         lower = mid;

       } else {

         upper = mid;

         break;

       }

     }

     assert_LU_OK;

   }

   // Sneak up on the value with a linear search of length ~16.

   while (true) {

     assert_LU_OK;

     mid = lower + 1;

     NOT_PRODUCT(++nmethod_stats.pc_desc_searches);

     if (mid->pc_offset() < pc_offset) {

       lower = mid;

     } else {

       upper = mid;

       break;

     }

   }

 #undef assert_LU_OK

   if (match_desc(upper, pc_offset, approximate)) {

     assert(upper == linear_search(this, pc_offset, approximate), "search ok");

     _pc_desc_cache.add_pc_desc(upper);

     return upper;

   } else {

     assert(NULL == linear_search(this, pc_offset, approximate), "search ok");

     return NULL;

   }

 }

 bool nmethod::check_all_dependencies() {

   bool found_check = false;

   // wholesale check of all dependencies

   for (Dependencies::DepStream deps(this); deps.next(); ) {

     if (deps.check_dependency() != NULL) {

       found_check = true;

       NOT_DEBUG(break);

     }

   }

   return found_check;  // tell caller if we found anything

 }

 bool nmethod::check_dependency_on(DepChange& changes) {

   // What has happened:

   // 1) a new class dependee has been added

   // 2) dependee and all its super classes have been marked

   bool found_check = false;  // set true if we are upset

   for (Dependencies::DepStream deps(this); deps.next(); ) {

     // Evaluate only relevant dependencies.

     if (deps.spot_check_dependency_at(changes) != NULL) {

       found_check = true;

       NOT_DEBUG(break);

     }

   }

   return found_check;

 }

 bool nmethod::is_evol_dependent_on(Klass* dependee) {

   InstanceKlass *dependee_ik = InstanceKlass::cast(dependee);

   Array<Method*>* dependee_methods = dependee_ik->methods();

   for (Dependencies::DepStream deps(this); deps.next(); ) {

     if (deps.type() == Dependencies::evol_method) {

       Method* method = deps.method_argument(0);

       for (int j = 0; j < dependee_methods->length(); j++) {

         if (dependee_methods->at(j) == method) {

           // RC_TRACE macro has an embedded ResourceMark

           RC_TRACE(0x01000000,

             ("Found evol dependency of nmethod %s.%s(%s) compile_id=%d on method %s.%s(%s)",

             _method->method_holder()->external_name(),

             _method->name()->as_C_string(),

             _method->signature()->as_C_string(), compile_id(),

             method->method_holder()->external_name(),

             method->name()->as_C_string(),

             method->signature()->as_C_string()));

           if (TraceDependencies || LogCompilation)

             deps.log_dependency(dependee);

           return true;

         }

       }

     }

   }

   return false;

 }

 // Called from mark_for_deoptimization, when dependee is invalidated.

 bool nmethod::is_dependent_on_method(Method* dependee) {

   for (Dependencies::DepStream deps(this); deps.next(); ) {

     if (deps.type() != Dependencies::evol_method)

       continue;

     Method* method = deps.method_argument(0);

     if (method == dependee) return true;

   }

   return false;

 }

 bool nmethod::is_patchable_at(address instr_addr) {

   assert(insts_contains(instr_addr), "wrong nmethod used");

   if (is_zombie()) {

     // a zombie may never be patched

     return false;

   }

   return true;

 }

 address nmethod::continuation_for_implicit_exception(address pc) {

   // Exception happened outside inline-cache check code => we are inside

   // an active nmethod => use cpc to determine a return address

   int exception_offset = pc - code_begin();

   int cont_offset = ImplicitExceptionTable(this).at( exception_offset );

 #ifdef ASSERT

   if (cont_offset == 0) {

     Thread* thread = ThreadLocalStorage::get_thread_slow();

     ResetNoHandleMark rnm; // Might be called from LEAF/QUICK ENTRY

     HandleMark hm(thread);

     ResourceMark rm(thread);

     CodeBlob* cb = CodeCache::find_blob(pc);

     assert(cb != NULL && cb == this, "");

     tty->print_cr("implicit exception happened at " INTPTR_FORMAT, pc);

     print();

     method()->print_codes();

     print_code();

     print_pcs();

   }

 #endif

   if (cont_offset == 0) {

     // Let the normal error handling report the exception

     return NULL;

   }

   return code_begin() + cont_offset;

 }

 void nmethod_init() {

   // make sure you didn't forget to adjust the filler fields

   assert(sizeof(nmethod) % oopSize == 0, "nmethod size must be multiple of a word");

 }

 //-------------------------------------------------------------------------------------------

 // QQQ might we make this work from a frame??

 nmethodLocker::nmethodLocker(address pc) {

   CodeBlob* cb = CodeCache::find_blob(pc);

   guarantee(cb != NULL && cb->is_nmethod(), "bad pc for a nmethod found");

   _nm = (nmethod*)cb;

   lock_nmethod(_nm);

 }

 // Only JvmtiDeferredEvent::compiled_method_unload_event()

 // should pass zombie_ok == true.

 void nmethodLocker::lock_nmethod(nmethod* nm, bool zombie_ok) {

   if (nm == NULL)  return;

   Atomic::inc(&nm->_lock_count);

   guarantee(zombie_ok || !nm->is_zombie(), "cannot lock a zombie method");

 }

 void nmethodLocker::unlock_nmethod(nmethod* nm) {

   if (nm == NULL)  return;

   Atomic::dec(&nm->_lock_count);

   guarantee(nm->_lock_count >= 0, "unmatched nmethod lock/unlock");

 }

 // -----------------------------------------------------------------------------

 // nmethod::get_deopt_original_pc

 //

 // Return the original PC for the given PC if:

 // (a) the given PC belongs to a nmethod and

 // (b) it is a deopt PC

 address nmethod::get_deopt_original_pc(const frame* fr) {

   if (fr->cb() == NULL)  return NULL;

   nmethod* nm = fr->cb()->as_nmethod_or_null();

   if (nm != NULL && nm->is_deopt_pc(fr->pc()))

     return nm->get_original_pc(fr);

   return NULL;

 }

 // -----------------------------------------------------------------------------

 // MethodHandle

 bool nmethod::is_method_handle_return(address return_pc) {

   if (!has_method_handle_invokes())  return false;

   PcDesc* pd = pc_desc_at(return_pc);

   if (pd == NULL)

     return false;

   return pd->is_method_handle_invoke();

 }

 // -----------------------------------------------------------------------------

 // Verification

 class VerifyOopsClosure: public OopClosure {

   nmethod* _nm;

   bool     _ok;

 public:

   VerifyOopsClosure(nmethod* nm) : _nm(nm), _ok(true) { }

   bool ok() { return _ok; }

   virtual void do_oop(oop* p) {

     if ((*p) == NULL || (*p)->is_oop())  return;

     if (_ok) {

       _nm->print_nmethod(true);

       _ok = false;

     }

     tty->print_cr("*** non-oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",

                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));

   }

   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }

 };

 void nmethod::verify() {

   // Hmm. OSR methods can be deopted but not marked as zombie or not_entrant

   // seems odd.

   if( is_zombie() || is_not_entrant() )

     return;

   // Make sure all the entry points are correctly aligned for patching.

   NativeJump::check_verified_entry_alignment(entry_point(), verified_entry_point());

   // assert(method()->is_oop(), "must be valid");

   ResourceMark rm;

   if (!CodeCache::contains(this)) {

     fatal(err_msg("nmethod at " INTPTR_FORMAT " not in zone", this));

   }

   if(is_native_method() )

     return;

   nmethod* nm = CodeCache::find_nmethod(verified_entry_point());

   if (nm != this) {

     fatal(err_msg("findNMethod did not find this nmethod (" INTPTR_FORMAT ")",

                   this));

   }

   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {

     if (! p->verify(this)) {

       tty->print_cr("\t\tin nmethod at " INTPTR_FORMAT " (pcs)", this);

     }

   }

   VerifyOopsClosure voc(this);

   oops_do(&voc);

   assert(voc.ok(), "embedded oops must be OK");

   verify_scavenge_root_oops();

   verify_scopes();

 }

 void nmethod::verify_interrupt_point(address call_site) {

   // This code does not work in release mode since

   // owns_lock only is available in debug mode.

   CompiledIC* ic = NULL;

   Thread *cur = Thread::current();

   if (CompiledIC_lock->owner() == cur ||

       ((cur->is_VM_thread() || cur->is_ConcurrentGC_thread()) &&

        SafepointSynchronize::is_at_safepoint())) {

     ic = CompiledIC_at(this, call_site);

     CHECK_UNHANDLED_OOPS_ONLY(Thread::current()->clear_unhandled_oops());

   } else {

     MutexLocker ml_verify (CompiledIC_lock);

     ic = CompiledIC_at(this, call_site);

   }

   PcDesc* pd = pc_desc_at(ic->end_of_call());

   assert(pd != NULL, "PcDesc must exist");

   for (ScopeDesc* sd = new ScopeDesc(this, pd->scope_decode_offset(),

                                      pd->obj_decode_offset(), pd->should_reexecute(),

                                      pd->return_oop());

        !sd->is_top(); sd = sd->sender()) {

     sd->verify();

   }

 }

 void nmethod::verify_scopes() {

   if( !method() ) return;       // Runtime stubs have no scope

   if (method()->is_native()) return; // Ignore stub methods.

   // iterate through all interrupt point

   // and verify the debug information is valid.

   RelocIterator iter((nmethod*)this);

   while (iter.next()) {

     address stub = NULL;

     switch (iter.type()) {

       case relocInfo::virtual_call_type:

         verify_interrupt_point(iter.addr());

         break;

       case relocInfo::opt_virtual_call_type:

         stub = iter.opt_virtual_call_reloc()->static_stub();

         verify_interrupt_point(iter.addr());

         break;

       case relocInfo::static_call_type:

         stub = iter.static_call_reloc()->static_stub();

         //verify_interrupt_point(iter.addr());

         break;

       case relocInfo::runtime_call_type:

         address destination = iter.reloc()->value();

         // Right now there is no way to find out which entries support

         // an interrupt point.  It would be nice if we had this

         // information in a table.

         break;

     }

     assert(stub == NULL || stub_contains(stub), "static call stub outside stub section");

   }

 }

 // -----------------------------------------------------------------------------

 // Non-product code

 #ifndef PRODUCT

 class DebugScavengeRoot: public OopClosure {

   nmethod* _nm;

   bool     _ok;

 public:

   DebugScavengeRoot(nmethod* nm) : _nm(nm), _ok(true) { }

   bool ok() { return _ok; }

   virtual void do_oop(oop* p) {

     if ((*p) == NULL || !(*p)->is_scavengable())  return;

     if (_ok) {

       _nm->print_nmethod(true);

       _ok = false;

     }

     tty->print_cr("*** scavengable oop "PTR_FORMAT" found at "PTR_FORMAT" (offset %d)",

                   (void *)(*p), (intptr_t)p, (int)((intptr_t)p - (intptr_t)_nm));

     (*p)->print();

   }

   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }

 };

 void nmethod::verify_scavenge_root_oops() {

   if (!on_scavenge_root_list()) {

     // Actually look inside, to verify the claim that it's clean.

     DebugScavengeRoot debug_scavenge_root(this);

     oops_do(&debug_scavenge_root);

     if (!debug_scavenge_root.ok())

       fatal("found an unadvertised bad scavengable oop in the code cache");

   }

   assert(scavenge_root_not_marked(), "");

 }

 #endif // PRODUCT

 // Printing operations

 void nmethod::print() const {

   ResourceMark rm;

   ttyLocker ttyl;   // keep the following output all in one block

   tty->print("Compiled method ");

   if (is_compiled_by_c1()) {

     tty->print("(c1) ");

   } else if (is_compiled_by_c2()) {

     tty->print("(c2) ");

   } else if (is_compiled_by_shark()) {

     tty->print("(shark) ");

   } else {

     tty->print("(nm) ");

   }

   print_on(tty, NULL);

   if (WizardMode) {

     tty->print("((nmethod*) "INTPTR_FORMAT ") ", this);

     tty->print(" for method " INTPTR_FORMAT , (address)method());

     tty->print(" { ");

     if (is_in_use())      tty->print("in_use ");

     if (is_not_entrant()) tty->print("not_entrant ");

     if (is_zombie())      tty->print("zombie ");

     if (is_unloaded())    tty->print("unloaded ");

     if (on_scavenge_root_list())  tty->print("scavenge_root ");

     tty->print_cr("}:");

   }

   if (size              () > 0) tty->print_cr(" total in heap  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               (address)this,

                                               (address)this + size(),

                                               size());

   if (relocation_size   () > 0) tty->print_cr(" relocation     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               relocation_begin(),

                                               relocation_end(),

                                               relocation_size());

   if (consts_size       () > 0) tty->print_cr(" constants      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               consts_begin(),

                                               consts_end(),

                                               consts_size());

   if (insts_size        () > 0) tty->print_cr(" main code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               insts_begin(),

                                               insts_end(),

                                               insts_size());

   if (stub_size         () > 0) tty->print_cr(" stub code      [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               stub_begin(),

                                               stub_end(),

                                               stub_size());

   if (oops_size         () > 0) tty->print_cr(" oops           [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               oops_begin(),

                                               oops_end(),

                                               oops_size());

   if (metadata_size      () > 0) tty->print_cr(" metadata       [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               metadata_begin(),

                                               metadata_end(),

                                               metadata_size());

   if (scopes_data_size  () > 0) tty->print_cr(" scopes data    [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               scopes_data_begin(),

                                               scopes_data_end(),

                                               scopes_data_size());

   if (scopes_pcs_size   () > 0) tty->print_cr(" scopes pcs     [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               scopes_pcs_begin(),

                                               scopes_pcs_end(),

                                               scopes_pcs_size());

   if (dependencies_size () > 0) tty->print_cr(" dependencies   [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               dependencies_begin(),

                                               dependencies_end(),

                                               dependencies_size());

   if (handler_table_size() > 0) tty->print_cr(" handler table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               handler_table_begin(),

                                               handler_table_end(),

                                               handler_table_size());

   if (nul_chk_table_size() > 0) tty->print_cr(" nul chk table  [" INTPTR_FORMAT "," INTPTR_FORMAT "] = %d",

                                               nul_chk_table_begin(),

                                               nul_chk_table_end(),

                                               nul_chk_table_size());

 }

 void nmethod::print_code() {

   HandleMark hm;

   ResourceMark m;

   Disassembler::decode(this);

 }

 #ifndef PRODUCT

 void nmethod::print_scopes() {

   // Find the first pc desc for all scopes in the code and print it.

   ResourceMark rm;

   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {

     if (p->scope_decode_offset() == DebugInformationRecorder::serialized_null)

       continue;

     ScopeDesc* sd = scope_desc_at(p->real_pc(this));

     sd->print_on(tty, p);

   }

 }

 void nmethod::print_dependencies() {

   ResourceMark rm;

   ttyLocker ttyl;   // keep the following output all in one block

   tty->print_cr("Dependencies:");

   for (Dependencies::DepStream deps(this); deps.next(); ) {

     deps.print_dependency();

     Klass* ctxk = deps.context_type();

     if (ctxk != NULL) {

       if (ctxk->oop_is_instance() && ((InstanceKlass*)ctxk)->is_dependent_nmethod(this)) {

         tty->print_cr("   [nmethod<=klass]%s", ctxk->external_name());

       }

     }

     deps.log_dependency();  // put it into the xml log also

   }

 }

 void nmethod::print_relocations() {

   ResourceMark m;       // in case methods get printed via the debugger

   tty->print_cr("relocations:");

   RelocIterator iter(this);

   iter.print();

   if (UseRelocIndex) {

     jint* index_end   = (jint*)relocation_end() - 1;

     jint  index_size  = *index_end;

     jint* index_start = (jint*)( (address)index_end - index_size );

     tty->print_cr("    index @" INTPTR_FORMAT ": index_size=%d", index_start, index_size);

     if (index_size > 0) {

       jint* ip;

       for (ip = index_start; ip+2 <= index_end; ip += 2)

         tty->print_cr("  (%d %d) addr=" INTPTR_FORMAT " @" INTPTR_FORMAT,

                       ip[0],

                       ip[1],

                       header_end()+ip[0],

                       relocation_begin()-1+ip[1]);

       for (; ip < index_end; ip++)

         tty->print_cr("  (%d ?)", ip[0]);

       tty->print_cr("          @" INTPTR_FORMAT ": index_size=%d", ip, *ip);

       ip++;

       tty->print_cr("reloc_end @" INTPTR_FORMAT ":", ip);

     }

   }

 }

 void nmethod::print_pcs() {

   ResourceMark m;       // in case methods get printed via debugger

   tty->print_cr("pc-bytecode offsets:");

   for (PcDesc* p = scopes_pcs_begin(); p < scopes_pcs_end(); p++) {

     p->print(this);

   }

 }

 #endif // PRODUCT