jdk8-mips64-public/hotspot: src/share/vm/compiler/oopMap.cpp@2d8a650513c2 (annotated)

src/share/vm/compiler/oopMap.cpp@2d8a650513c2 (annotated)

src/share/vm/compiler/oopMap.cpp

Fri, 29 Apr 2016 00:06:10 +0800

author: aoqi
date: Fri, 29 Apr 2016 00:06:10 +0800
changeset 1: 2d8a650513c2
parent 0: f90c822e73f8
child 6876: 710a3c8b516e
permissions: -rw-r--r--

Added MIPS 64-bit port.

 /*
  * Copyright (c) 1998, 2014, 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/codeBlob.hpp"
 #include "code/codeCache.hpp"
 #include "code/nmethod.hpp"
 #include "code/scopeDesc.hpp"
 #include "compiler/oopMap.hpp"
 #include "gc_interface/collectedHeap.hpp"
 #include "memory/allocation.inline.hpp"
 #include "memory/resourceArea.hpp"
 #include "runtime/frame.inline.hpp"
 #include "runtime/signature.hpp"
 #ifdef COMPILER1
 #include "c1/c1_Defs.hpp"
 #endif
 // OopMapStream
 OopMapStream::OopMapStream(OopMap* oop_map) {
   if(oop_map->omv_data() == NULL) {
     _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
   } else {
     _stream = new CompressedReadStream(oop_map->omv_data());
   }
   _mask = OopMapValue::type_mask_in_place;
   _size = oop_map->omv_count();
   _position = 0;
   _valid_omv = false;
 }
 OopMapStream::OopMapStream(OopMap* oop_map, int oop_types_mask) {
   if(oop_map->omv_data() == NULL) {
     _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
   } else {
     _stream = new CompressedReadStream(oop_map->omv_data());
   }
   _mask = oop_types_mask;
   _size = oop_map->omv_count();
   _position = 0;
   _valid_omv = false;
 }
 void OopMapStream::find_next() {
   while(_position++ < _size) {
     _omv.read_from(_stream);
     if(((int)_omv.type() & _mask) > 0) {
       _valid_omv = true;
       return;
     }
   }
   _valid_omv = false;
 }
 // OopMap
 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
 // slots to hold 4-byte values like ints and floats in the LP64 build.
 OopMap::OopMap(int frame_size, int arg_count) {
   // OopMaps are usually quite so small, so pick a small initial size
   set_write_stream(new CompressedWriteStream(32));
   set_omv_data(NULL);
   set_omv_count(0);
 #ifdef ASSERT
   _locs_length = VMRegImpl::stack2reg(0)->value() + frame_size + arg_count;
   _locs_used   = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
 #endif
 }
 OopMap::OopMap(OopMap::DeepCopyToken, OopMap* source) {
   // This constructor does a deep copy
   // of the source OopMap.
   set_write_stream(new CompressedWriteStream(source->omv_count() * 2));
   set_omv_data(NULL);
   set_omv_count(0);
   set_offset(source->offset());
 #ifdef ASSERT
   _locs_length = source->_locs_length;
   _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
 #endif
   // We need to copy the entries too.
   for (OopMapStream oms(source); !oms.is_done(); oms.next()) {
     OopMapValue omv = oms.current();
     omv.write_on(write_stream());
     increment_count();
   }
 }
 OopMap* OopMap::deep_copy() {
   return new OopMap(_deep_copy_token, this);
 }
 void OopMap::copy_to(address addr) {
   memcpy(addr,this,sizeof(OopMap));
   memcpy(addr + sizeof(OopMap),write_stream()->buffer(),write_stream()->position());
   OopMap* new_oop = (OopMap*)addr;
   new_oop->set_omv_data_size(write_stream()->position());
   new_oop->set_omv_data((unsigned char *)(addr + sizeof(OopMap)));
   new_oop->set_write_stream(NULL);
 }
 int OopMap::heap_size() const {
   int size = sizeof(OopMap);
   int align = sizeof(void *) - 1;
   if(write_stream() != NULL) {
     size += write_stream()->position();
   } else {
     size += omv_data_size();
   }
   // Align to a reasonable ending point
   size = ((size+align) & ~align);
   return size;
 }
 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
 // slots to hold 4-byte values like ints and floats in the LP64 build.
 void OopMap::set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional) {
   assert(reg->value() < _locs_length, "too big reg value for stack size");
   assert( _locs_used[reg->value()] == OopMapValue::unused_value, "cannot insert twice" );
   debug_only( _locs_used[reg->value()] = x; )
   OopMapValue o(reg, x);
   if(x == OopMapValue::callee_saved_value) {
     // This can never be a stack location, so we don't need to transform it.
     assert(optional->is_reg(), "Trying to callee save a stack location");
     o.set_content_reg(optional);
   } else if(x == OopMapValue::derived_oop_value) {
     o.set_content_reg(optional);
   }
   o.write_on(write_stream());
   increment_count();
 }
 void OopMap::set_oop(VMReg reg) {
   set_xxx(reg, OopMapValue::oop_value, VMRegImpl::Bad());
 }
 void OopMap::set_value(VMReg reg) {
   // At this time, we only need value entries in our OopMap when ZapDeadCompiledLocals is active.
   if (ZapDeadCompiledLocals)
     set_xxx(reg, OopMapValue::value_value, VMRegImpl::Bad());
 }
 void OopMap::set_narrowoop(VMReg reg) {
   set_xxx(reg, OopMapValue::narrowoop_value, VMRegImpl::Bad());
 }
 void OopMap::set_callee_saved(VMReg reg, VMReg caller_machine_register ) {
   set_xxx(reg, OopMapValue::callee_saved_value, caller_machine_register);
 }
 void OopMap::set_derived_oop(VMReg reg, VMReg derived_from_local_register ) {
   if( reg == derived_from_local_register ) {
     // Actually an oop, derived shares storage with base,
     set_oop(reg);
   } else {
     set_xxx(reg, OopMapValue::derived_oop_value, derived_from_local_register);
   }
 }
 // OopMapSet
 OopMapSet::OopMapSet() {
   set_om_size(MinOopMapAllocation);
   set_om_count(0);
   OopMap** temp = NEW_RESOURCE_ARRAY(OopMap*, om_size());
   set_om_data(temp);
 }
 void OopMapSet::grow_om_data() {
   int new_size = om_size() * 2;
   OopMap** new_data = NEW_RESOURCE_ARRAY(OopMap*, new_size);
   memcpy(new_data,om_data(),om_size() * sizeof(OopMap*));
   set_om_size(new_size);
   set_om_data(new_data);
 }
 void OopMapSet::copy_to(address addr) {
   address temp = addr;
   int align = sizeof(void *) - 1;
   // Copy this
   memcpy(addr,this,sizeof(OopMapSet));
   temp += sizeof(OopMapSet);
   temp = (address)((intptr_t)(temp + align) & ~align);
   // Do the needed fixups to the new OopMapSet
   OopMapSet* new_set = (OopMapSet*)addr;
   new_set->set_om_data((OopMap**)temp);
   // Allow enough space for the OopMap pointers
   temp += (om_count() * sizeof(OopMap*));
   for(int i=0; i < om_count(); i++) {
     OopMap* map = at(i);
     map->copy_to((address)temp);
     new_set->set(i,(OopMap*)temp);
     temp += map->heap_size();
   }
   // This "locks" the OopMapSet
   new_set->set_om_size(-1);
 }
 void OopMapSet::add_gc_map(int pc_offset, OopMap *map ) {
   assert(om_size() != -1,"Cannot grow a fixed OopMapSet");
   if(om_count() >= om_size()) {
     grow_om_data();
   }
   map->set_offset(pc_offset);
 #ifdef ASSERT
   if(om_count() > 0) {
     OopMap* last = at(om_count()-1);
     if (last->offset() == map->offset() ) {
       fatal("OopMap inserted twice");
     }
     if(last->offset() > map->offset()) {
       tty->print_cr( "WARNING, maps not sorted: pc[%d]=%d, pc[%d]=%d",
                       om_count(),last->offset(),om_count()+1,map->offset());
     }
   }
 #endif // ASSERT
   set(om_count(),map);
   increment_count();
 }
 int OopMapSet::heap_size() const {
   // The space we use
   int size = sizeof(OopMap);
   int align = sizeof(void *) - 1;
   size = ((size+align) & ~align);
   size += om_count() * sizeof(OopMap*);
   // Now add in the space needed for the indivdiual OopMaps
   for(int i=0; i < om_count(); i++) {
     size += at(i)->heap_size();
   }
   // We don't need to align this, it will be naturally pointer aligned
   return size;
 }
 OopMap* OopMapSet::singular_oop_map() {
   guarantee(om_count() == 1, "Make sure we only have a single gc point");
   return at(0);
 }
 OopMap* OopMapSet::find_map_at_offset(int pc_offset) const {
   int i, len = om_count();
   assert( len > 0, "must have pointer maps" );
   // Scan through oopmaps. Stop when current offset is either equal or greater
   // than the one we are looking for.
   for( i = 0; i < len; i++) {
     if( at(i)->offset() >= pc_offset )
       break;
   }
   assert( i < len, "oopmap not found" );
   OopMap* m = at(i);
   assert( m->offset() == pc_offset, "oopmap not found" );
   return m;
 }
 class DoNothingClosure: public OopClosure {
  public:
   void do_oop(oop* p)       {}
   void do_oop(narrowOop* p) {}
 };
 static DoNothingClosure do_nothing;
 static void add_derived_oop(oop* base, oop* derived) {
 #ifndef TIERED
   COMPILER1_PRESENT(ShouldNotReachHere();)
 #endif // TIERED
 #ifdef COMPILER2
   DerivedPointerTable::add(derived, base);
 #endif // COMPILER2
 }
 #ifndef PRODUCT
 static void trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map) {
   // Print oopmap and regmap
   tty->print_cr("------ ");
   CodeBlob* cb = fr->cb();
   OopMapSet* maps = cb->oop_maps();
   OopMap* map = cb->oop_map_for_return_address(fr->pc());
   map->print();
   if( cb->is_nmethod() ) {
     nmethod* nm = (nmethod*)cb;
     // native wrappers have no scope data, it is implied
     if (nm->is_native_method()) {
       tty->print("bci: 0 (native)");
     } else {
       ScopeDesc* scope  = nm->scope_desc_at(fr->pc());
       tty->print("bci: %d ",scope->bci());
     }
   }
   tty->cr();
   fr->print_on(tty);
   tty->print("     ");
   cb->print_value_on(tty);  tty->cr();
   reg_map->print();
   tty->print_cr("------ ");
 }
 #endif // PRODUCT
 void OopMapSet::oops_do(const frame *fr, const RegisterMap* reg_map, OopClosure* f) {
   // add derived oops to a table
   all_do(fr, reg_map, f, add_derived_oop, &do_nothing);
 }
 void OopMapSet::all_do(const frame *fr, const RegisterMap *reg_map,
                        OopClosure* oop_fn, void derived_oop_fn(oop*, oop*),
                        OopClosure* value_fn) {
   CodeBlob* cb = fr->cb();
   assert(cb != NULL, "no codeblob");
   NOT_PRODUCT(if (TraceCodeBlobStacks) trace_codeblob_maps(fr, reg_map);)
   OopMapSet* maps = cb->oop_maps();
   OopMap* map = cb->oop_map_for_return_address(fr->pc());
   assert(map != NULL, "no ptr map found");
   // handle derived pointers first (otherwise base pointer may be
   // changed before derived pointer offset has been collected)
   OopMapValue omv;
   {
     OopMapStream oms(map,OopMapValue::derived_oop_value);
     if (!oms.is_done()) {
 #ifndef TIERED
       COMPILER1_PRESENT(ShouldNotReachHere();)
 #endif // !TIERED
       // Protect the operation on the derived pointers.  This
       // protects the addition of derived pointers to the shared
       // derived pointer table in DerivedPointerTable::add().
       MutexLockerEx x(DerivedPointerTableGC_lock, Mutex::_no_safepoint_check_flag);
       do {
         omv = oms.current();
         oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
         if ( loc != NULL ) {
           oop *base_loc    = fr->oopmapreg_to_location(omv.content_reg(), reg_map);
           oop *derived_loc = loc;
           oop val = *base_loc;
           if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
             // Ignore NULL oops and decoded NULL narrow oops which
             // equal to Universe::narrow_oop_base when a narrow oop
             // implicit null check is used in compiled code.
             // The narrow_oop_base could be NULL or be the address
             // of the page below heap depending on compressed oops mode.
           } else
             derived_oop_fn(base_loc, derived_loc);
         }
         oms.next();
       }  while (!oms.is_done());
     }
   }
   // We want coop, value and oop oop_types
   int mask = OopMapValue::oop_value | OopMapValue::value_value | OopMapValue::narrowoop_value;
   {
     for (OopMapStream oms(map,mask); !oms.is_done(); oms.next()) {
       omv = oms.current();
       oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
       if ( loc != NULL ) {
         if ( omv.type() == OopMapValue::oop_value ) {
           oop val = *loc;
           if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
             // Ignore NULL oops and decoded NULL narrow oops which
             // equal to Universe::narrow_oop_base when a narrow oop
             // implicit null check is used in compiled code.
             // The narrow_oop_base could be NULL or be the address
             // of the page below heap depending on compressed oops mode.
             continue;
           }
 #ifdef ASSERT
           if ((((uintptr_t)loc & (sizeof(*loc)-1)) != 0) ||
              !Universe::heap()->is_in_or_null(*loc)) {
             tty->print_cr("# Found non oop pointer.  Dumping state at failure");
             // try to dump out some helpful debugging information
             trace_codeblob_maps(fr, reg_map);
             omv.print();
             tty->print_cr("register r");
             omv.reg()->print();
             tty->print_cr("loc = %p *loc = %p\n", loc, (address)*loc);
             // do the real assert.
             assert(Universe::heap()->is_in_or_null(*loc), "found non oop pointer");
           }
 #endif // ASSERT
           oop_fn->do_oop(loc);
         } else if ( omv.type() == OopMapValue::value_value ) {
           assert((*loc) == (oop)NULL || !Universe::is_narrow_oop_base(*loc),
                  "found invalid value pointer");
           value_fn->do_oop(loc);
         } else if ( omv.type() == OopMapValue::narrowoop_value ) {
           narrowOop *nl = (narrowOop*)loc;
 #ifndef VM_LITTLE_ENDIAN
           if (!omv.reg()->is_stack()) {
             // compressed oops in registers only take up 4 bytes of an
             // 8 byte register but they are in the wrong part of the
             // word so adjust loc to point at the right place.
             nl = (narrowOop*)((address)nl + 4);
           }
 #endif
           oop_fn->do_oop(nl);
         }
       }
     }
   }
 }
 // Update callee-saved register info for the following frame
 void OopMapSet::update_register_map(const frame *fr, RegisterMap *reg_map) {
   ResourceMark rm;
   CodeBlob* cb = fr->cb();
   assert(cb != NULL, "no codeblob");
   // Any reg might be saved by a safepoint handler (see generate_handler_blob).
   const int max_saved_on_entry_reg_count = ConcreteRegisterImpl::number_of_registers;
   assert( reg_map->_update_for_id == NULL || fr->is_older(reg_map->_update_for_id),
          "already updated this map; do not 'update' it twice!" );
   debug_only(reg_map->_update_for_id = fr->id());
   // Check if caller must update oop argument
   assert((reg_map->include_argument_oops() ||
           !cb->caller_must_gc_arguments(reg_map->thread())),
          "include_argument_oops should already be set");
   int nof_callee = 0;
   oop*        locs[2*max_saved_on_entry_reg_count+1];
   VMReg regs[2*max_saved_on_entry_reg_count+1];
   // ("+1" because max_saved_on_entry_reg_count might be zero)
   // Scan through oopmap and find location of all callee-saved registers
   // (we do not do update in place, since info could be overwritten)
   address pc = fr->pc();
   OopMap* map  = cb->oop_map_for_return_address(pc);
   assert(map != NULL, " no ptr map found");
   OopMapValue omv;
   for(OopMapStream oms(map,OopMapValue::callee_saved_value); !oms.is_done(); oms.next()) {
     omv = oms.current();
     assert(nof_callee < 2*max_saved_on_entry_reg_count, "overflow");
     regs[nof_callee] = omv.content_reg();
     locs[nof_callee] = fr->oopmapreg_to_location(omv.reg(),reg_map);
     nof_callee++;
   }
   // Check that runtime stubs save all callee-saved registers
 #ifdef COMPILER2
   assert(cb->is_compiled_by_c1() || !cb->is_runtime_stub() ||
          (nof_callee >= SAVED_ON_ENTRY_REG_COUNT || nof_callee >= C_SAVED_ON_ENTRY_REG_COUNT),
          "must save all");
 #endif // COMPILER2
   // Copy found callee-saved register to reg_map
   for(int i = 0; i < nof_callee; i++) {
     reg_map->set_location(regs[i], (address)locs[i]);
   }
 }
 //=============================================================================
 // Non-Product code
 #ifndef PRODUCT
 bool OopMap::has_derived_pointer() const {
 #ifndef TIERED
   COMPILER1_PRESENT(return false);
 #endif // !TIERED
 #ifdef COMPILER2
   OopMapStream oms((OopMap*)this,OopMapValue::derived_oop_value);
   return oms.is_done();
 #else
   return false;
 #endif // COMPILER2
 }
 #endif //PRODUCT
 // Printing code is present in product build for -XX:+PrintAssembly.
 static
 void print_register_type(OopMapValue::oop_types x, VMReg optional,
                          outputStream* st) {
   switch( x ) {
   case OopMapValue::oop_value:
     st->print("Oop");
     break;
   case OopMapValue::value_value:
     st->print("Value");
     break;
   case OopMapValue::narrowoop_value:
     st->print("NarrowOop");
     break;
   case OopMapValue::callee_saved_value:
     st->print("Callers_");
     optional->print_on(st);
     break;
   case OopMapValue::derived_oop_value:
     st->print("Derived_oop_");
     optional->print_on(st);
     break;
   default:
     ShouldNotReachHere();
   }
 }
 void OopMapValue::print_on(outputStream* st) const {
   reg()->print_on(st);
   st->print("=");
   print_register_type(type(),content_reg(),st);
   st->print(" ");
 }
 void OopMap::print_on(outputStream* st) const {
   OopMapValue omv;
   st->print("OopMap{");
   for(OopMapStream oms((OopMap*)this); !oms.is_done(); oms.next()) {
     omv = oms.current();
     omv.print_on(st);
   }
   st->print("off=%d}", (int) offset());
 }
 void OopMapSet::print_on(outputStream* st) const {
   int i, len = om_count();
   st->print_cr("OopMapSet contains %d OopMaps\n",len);
   for( i = 0; i < len; i++) {
     OopMap* m = at(i);
     st->print_cr("#%d ",i);
     m->print_on(st);
     st->cr();
   }
 }
 //------------------------------DerivedPointerTable---------------------------
 #ifdef COMPILER2
 class DerivedPointerEntry : public CHeapObj<mtCompiler> {
  private:
   oop*     _location; // Location of derived pointer (also pointing to the base)
   intptr_t _offset;   // Offset from base pointer
  public:
   DerivedPointerEntry(oop* location, intptr_t offset) { _location = location; _offset = offset; }
   oop* location()    { return _location; }
   intptr_t  offset() { return _offset; }
 };
 GrowableArray<DerivedPointerEntry*>* DerivedPointerTable::_list = NULL;
 bool DerivedPointerTable::_active = false;
 void DerivedPointerTable::clear() {
   // The first time, we create the list.  Otherwise it should be
   // empty.  If not, then we have probably forgotton to call
   // update_pointers after last GC/Scavenge.
   assert (!_active, "should not be active");
   assert(_list == NULL || _list->length() == 0, "table not empty");
   if (_list == NULL) {
     _list = new (ResourceObj::C_HEAP, mtCompiler) GrowableArray<DerivedPointerEntry*>(10, true); // Allocated on C heap
   }
   _active = true;
 }
 // Returns value of location as an int
 intptr_t value_of_loc(oop *pointer) { return cast_from_oop<intptr_t>((*pointer)); }
 void DerivedPointerTable::add(oop *derived_loc, oop *base_loc) {
   assert(Universe::heap()->is_in_or_null(*base_loc), "not an oop");
   assert(derived_loc != base_loc, "Base and derived in same location");
   if (_active) {
     assert(*derived_loc != (oop)base_loc, "location already added");
     assert(_list != NULL, "list must exist");
     intptr_t offset = value_of_loc(derived_loc) - value_of_loc(base_loc);
     // This assert is invalid because derived pointers can be
     // arbitrarily far away from their base.
     // assert(offset >= -1000000, "wrong derived pointer info");
     if (TraceDerivedPointers) {
       tty->print_cr(
         "Add derived pointer@" INTPTR_FORMAT
         " - Derived: " INTPTR_FORMAT
         " Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: " INTX_FORMAT ")",
         p2i(derived_loc), p2i((address)*derived_loc), p2i((address)*base_loc), p2i(base_loc), offset
       );
     }
     // Set derived oop location to point to base.
     *derived_loc = (oop)base_loc;
     assert_lock_strong(DerivedPointerTableGC_lock);
     DerivedPointerEntry *entry = new DerivedPointerEntry(derived_loc, offset);
     _list->append(entry);
   }
 }
 void DerivedPointerTable::update_pointers() {
   assert(_list != NULL, "list must exist");
   for(int i = 0; i < _list->length(); i++) {
     DerivedPointerEntry* entry = _list->at(i);
     oop* derived_loc = entry->location();
     intptr_t offset  = entry->offset();
     // The derived oop was setup to point to location of base
     oop  base        = **(oop**)derived_loc;
     assert(Universe::heap()->is_in_or_null(base), "must be an oop");
     *derived_loc = (oop)(((address)base) + offset);
     assert(value_of_loc(derived_loc) - value_of_loc(&base) == offset, "sanity check");
     if (TraceDerivedPointers) {
       tty->print_cr("Updating derived pointer@" INTPTR_FORMAT
                     " - Derived: " INTPTR_FORMAT "  Base: " INTPTR_FORMAT " (Offset: " INTX_FORMAT ")",
           p2i(derived_loc), p2i((address)*derived_loc), p2i((address)base), offset);
     }
     // Delete entry
     delete entry;
     _list->at_put(i, NULL);
   }
   // Clear list, so it is ready for next traversal (this is an invariant)
   if (TraceDerivedPointers && !_list->is_empty()) {
     tty->print_cr("--------------------------");
   }
   _list->clear();
   _active = false;
 }
 #endif // COMPILER2

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/compiler/oopMap.cpp@2d8a650513c2 (annotated)

src/share/vm/compiler/oopMap.cpp