jdk8-mips64-public/hotspot: src/share/vm/runtime/deoptimization.cpp@52fed2ec0afb (annotated)

src/share/vm/runtime/deoptimization.cpp@52fed2ec0afb (annotated)

src/share/vm/runtime/deoptimization.cpp

Tue, 11 Mar 2008 11:25:13 -0700

author: kvn
date: Tue, 11 Mar 2008 11:25:13 -0700
changeset 479: 52fed2ec0afb
parent 435: a61af66fc99e
child 518: d3cd40645d0d
permissions: -rw-r--r--

6667620: (Escape Analysis) fix deoptimization for scalar replaced objects
Summary: Deoptimization code for reallocation and relocking scalar replaced objects has to be fixed.
Reviewed-by: rasbold, never

 /*
  * Copyright 1997-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_deoptimization.cpp.incl"
 bool DeoptimizationMarker::_is_active = false;
 Deoptimization::UnrollBlock::UnrollBlock(int  size_of_deoptimized_frame,
                                          int  caller_adjustment,
                                          int  number_of_frames,
                                          intptr_t* frame_sizes,
                                          address* frame_pcs,
                                          BasicType return_type) {
   _size_of_deoptimized_frame = size_of_deoptimized_frame;
   _caller_adjustment         = caller_adjustment;
   _number_of_frames          = number_of_frames;
   _frame_sizes               = frame_sizes;
   _frame_pcs                 = frame_pcs;
   _register_block            = NEW_C_HEAP_ARRAY(intptr_t, RegisterMap::reg_count * 2);
   _return_type               = return_type;
   // PD (x86 only)
   _counter_temp              = 0;
   _initial_fp                = 0;
   _unpack_kind               = 0;
   _sender_sp_temp            = 0;
   _total_frame_sizes         = size_of_frames();
 }
 Deoptimization::UnrollBlock::~UnrollBlock() {
   FREE_C_HEAP_ARRAY(intptr_t, _frame_sizes);
   FREE_C_HEAP_ARRAY(intptr_t, _frame_pcs);
   FREE_C_HEAP_ARRAY(intptr_t, _register_block);
 }
 intptr_t* Deoptimization::UnrollBlock::value_addr_at(int register_number) const {
   assert(register_number < RegisterMap::reg_count, "checking register number");
   return &_register_block[register_number * 2];
 }
 int Deoptimization::UnrollBlock::size_of_frames() const {
   // Acount first for the adjustment of the initial frame
   int result = _caller_adjustment;
   for (int index = 0; index < number_of_frames(); index++) {
     result += frame_sizes()[index];
   }
   return result;
 }
 void Deoptimization::UnrollBlock::print() {
   ttyLocker ttyl;
   tty->print_cr("UnrollBlock");
   tty->print_cr("  size_of_deoptimized_frame = %d", _size_of_deoptimized_frame);
   tty->print(   "  frame_sizes: ");
   for (int index = 0; index < number_of_frames(); index++) {
     tty->print("%d ", frame_sizes()[index]);
   }
   tty->cr();
 }
 // In order to make fetch_unroll_info work properly with escape
 // analysis, The method was changed from JRT_LEAF to JRT_BLOCK_ENTRY and
 // ResetNoHandleMark and HandleMark were removed from it. The actual reallocation
 // of previously eliminated objects occurs in realloc_objects, which is
 // called from the method fetch_unroll_info_helper below.
 JRT_BLOCK_ENTRY(Deoptimization::UnrollBlock*, Deoptimization::fetch_unroll_info(JavaThread* thread))
   // It is actually ok to allocate handles in a leaf method. It causes no safepoints,
   // but makes the entry a little slower. There is however a little dance we have to
   // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro
   // fetch_unroll_info() is called at the beginning of the deoptimization
   // handler. Note this fact before we start generating temporary frames
   // that can confuse an asynchronous stack walker. This counter is
   // decremented at the end of unpack_frames().
   thread->inc_in_deopt_handler();
   return fetch_unroll_info_helper(thread);
 JRT_END
 // This is factored, since it is both called from a JRT_LEAF (deoptimization) and a JRT_ENTRY (uncommon_trap)
 Deoptimization::UnrollBlock* Deoptimization::fetch_unroll_info_helper(JavaThread* thread) {
   // Note: there is a safepoint safety issue here. No matter whether we enter
   // via vanilla deopt or uncommon trap we MUST NOT stop at a safepoint once
   // the vframeArray is created.
   //
   // Allocate our special deoptimization ResourceMark
   DeoptResourceMark* dmark = new DeoptResourceMark(thread);
   assert(thread->deopt_mark() == NULL, "Pending deopt!");
   thread->set_deopt_mark(dmark);
   frame stub_frame = thread->last_frame(); // Makes stack walkable as side effect
   RegisterMap map(thread, true);
   RegisterMap dummy_map(thread, false);
   // Now get the deoptee with a valid map
   frame deoptee = stub_frame.sender(&map);
   // Create a growable array of VFrames where each VFrame represents an inlined
   // Java frame.  This storage is allocated with the usual system arena.
   assert(deoptee.is_compiled_frame(), "Wrong frame type");
   GrowableArray<compiledVFrame*>* chunk = new GrowableArray<compiledVFrame*>(10);
   vframe* vf = vframe::new_vframe(&deoptee, &map, thread);
   while (!vf->is_top()) {
     assert(vf->is_compiled_frame(), "Wrong frame type");
     chunk->push(compiledVFrame::cast(vf));
     vf = vf->sender();
   }
   assert(vf->is_compiled_frame(), "Wrong frame type");
   chunk->push(compiledVFrame::cast(vf));
 #ifdef COMPILER2
   // Reallocate the non-escaping objects and restore their fields. Then
   // relock objects if synchronization on them was eliminated.
   if (DoEscapeAnalysis) {
     if (EliminateAllocations) {
       GrowableArray<ScopeValue*>* objects = chunk->at(0)->scope()->objects();
       bool reallocated = false;
       if (objects != NULL) {
         JRT_BLOCK
           reallocated = realloc_objects(thread, &deoptee, objects, THREAD);
         JRT_END
       }
       if (reallocated) {
         reassign_fields(&deoptee, &map, objects);
 #ifndef PRODUCT
         if (TraceDeoptimization) {
           ttyLocker ttyl;
           tty->print_cr("REALLOC OBJECTS in thread " INTPTR_FORMAT, thread);
           print_objects(objects);
       }
 #endif
       }
     }
     if (EliminateLocks) {
       for (int i = 0; i < chunk->length(); i++) {
         GrowableArray<MonitorValue*>* monitors = chunk->at(i)->scope()->monitors();
         if (monitors != NULL) {
           relock_objects(&deoptee, &map, monitors);
 #ifndef PRODUCT
           if (TraceDeoptimization) {
             ttyLocker ttyl;
             tty->print_cr("RELOCK OBJECTS in thread " INTPTR_FORMAT, thread);
             for (int j = 0; j < monitors->length(); j++) {
               MonitorValue* mv = monitors->at(j);
               if (mv->eliminated()) {
                 StackValue* owner = StackValue::create_stack_value(&deoptee, &map, mv->owner());
                 tty->print_cr("     object <" INTPTR_FORMAT "> locked", owner->get_obj()());
               }
             }
           }
 #endif
         }
       }
     }
   }
 #endif // COMPILER2
   // Ensure that no safepoint is taken after pointers have been stored
   // in fields of rematerialized objects.  If a safepoint occurs from here on
   // out the java state residing in the vframeArray will be missed.
   No_Safepoint_Verifier no_safepoint;
   vframeArray* array = create_vframeArray(thread, deoptee, &map, chunk);
   assert(thread->vframe_array_head() == NULL, "Pending deopt!");;
   thread->set_vframe_array_head(array);
   // Now that the vframeArray has been created if we have any deferred local writes
   // added by jvmti then we can free up that structure as the data is now in the
   // vframeArray
   if (thread->deferred_locals() != NULL) {
     GrowableArray<jvmtiDeferredLocalVariableSet*>* list = thread->deferred_locals();
     int i = 0;
     do {
       // Because of inlining we could have multiple vframes for a single frame
       // and several of the vframes could have deferred writes. Find them all.
       if (list->at(i)->id() == array->original().id()) {
         jvmtiDeferredLocalVariableSet* dlv = list->at(i);
         list->remove_at(i);
         // individual jvmtiDeferredLocalVariableSet are CHeapObj's
         delete dlv;
       } else {
         i++;
       }
     } while ( i < list->length() );
     if (list->length() == 0) {
       thread->set_deferred_locals(NULL);
       // free the list and elements back to C heap.
       delete list;
     }
   }
   // Compute the caller frame based on the sender sp of stub_frame and stored frame sizes info.
   CodeBlob* cb = stub_frame.cb();
   // Verify we have the right vframeArray
   assert(cb->frame_size() >= 0, "Unexpected frame size");
   intptr_t* unpack_sp = stub_frame.sp() + cb->frame_size();
 #ifdef ASSERT
   assert(cb->is_deoptimization_stub() || cb->is_uncommon_trap_stub(), "just checking");
   Events::log("fetch unroll sp " INTPTR_FORMAT, unpack_sp);
 #endif
   // This is a guarantee instead of an assert because if vframe doesn't match
   // we will unpack the wrong deoptimized frame and wind up in strange places
   // where it will be very difficult to figure out what went wrong. Better
   // to die an early death here than some very obscure death later when the
   // trail is cold.
   // Note: on ia64 this guarantee can be fooled by frames with no memory stack
   // in that it will fail to detect a problem when there is one. This needs
   // more work in tiger timeframe.
   guarantee(array->unextended_sp() == unpack_sp, "vframe_array_head must contain the vframeArray to unpack");
   int number_of_frames = array->frames();
   // Compute the vframes' sizes.  Note that frame_sizes[] entries are ordered from outermost to innermost
   // virtual activation, which is the reverse of the elements in the vframes array.
   intptr_t* frame_sizes = NEW_C_HEAP_ARRAY(intptr_t, number_of_frames);
   // +1 because we always have an interpreter return address for the final slot.
   address* frame_pcs = NEW_C_HEAP_ARRAY(address, number_of_frames + 1);
   int callee_parameters = 0;
   int callee_locals = 0;
   int popframe_extra_args = 0;
   // Create an interpreter return address for the stub to use as its return
   // address so the skeletal frames are perfectly walkable
   frame_pcs[number_of_frames] = Interpreter::deopt_entry(vtos, 0);
   // PopFrame requires that the preserved incoming arguments from the recently-popped topmost
   // activation be put back on the expression stack of the caller for reexecution
   if (JvmtiExport::can_pop_frame() && thread->popframe_forcing_deopt_reexecution()) {
     popframe_extra_args = in_words(thread->popframe_preserved_args_size_in_words());
   }
   //
   // frame_sizes/frame_pcs[0] oldest frame (int or c2i)
   // frame_sizes/frame_pcs[1] next oldest frame (int)
   // frame_sizes/frame_pcs[n] youngest frame (int)
   //
   // Now a pc in frame_pcs is actually the return address to the frame's caller (a frame
   // owns the space for the return address to it's caller).  Confusing ain't it.
   //
   // The vframe array can address vframes with indices running from
   // 0.._frames-1. Index  0 is the youngest frame and _frame - 1 is the oldest (root) frame.
   // When we create the skeletal frames we need the oldest frame to be in the zero slot
   // in the frame_sizes/frame_pcs so the assembly code can do a trivial walk.
   // so things look a little strange in this loop.
   //
   for (int index = 0; index < array->frames(); index++ ) {
     // frame[number_of_frames - 1 ] = on_stack_size(youngest)
     // frame[number_of_frames - 2 ] = on_stack_size(sender(youngest))
     // frame[number_of_frames - 3 ] = on_stack_size(sender(sender(youngest)))
     frame_sizes[number_of_frames - 1 - index] = BytesPerWord * array->element(index)->on_stack_size(callee_parameters,
                                                                                                     callee_locals,
                                                                                                     index == 0,
                                                                                                     popframe_extra_args);
     // This pc doesn't have to be perfect just good enough to identify the frame
     // as interpreted so the skeleton frame will be walkable
     // The correct pc will be set when the skeleton frame is completely filled out
     // The final pc we store in the loop is wrong and will be overwritten below
     frame_pcs[number_of_frames - 1 - index ] = Interpreter::deopt_entry(vtos, 0) - frame::pc_return_offset;
     callee_parameters = array->element(index)->method()->size_of_parameters();
     callee_locals = array->element(index)->method()->max_locals();
     popframe_extra_args = 0;
   }
   // Compute whether the root vframe returns a float or double value.
   BasicType return_type;
   {
     HandleMark hm;
     methodHandle method(thread, array->element(0)->method());
     Bytecode_invoke* invoke = Bytecode_invoke_at_check(method, array->element(0)->bci());
     return_type = (invoke != NULL) ? invoke->result_type(thread) : T_ILLEGAL;
   }
   // Compute information for handling adapters and adjusting the frame size of the caller.
   int caller_adjustment = 0;
   // Find the current pc for sender of the deoptee. Since the sender may have been deoptimized
   // itself since the deoptee vframeArray was created we must get a fresh value of the pc rather
   // than simply use array->sender.pc(). This requires us to walk the current set of frames
   //
   frame deopt_sender = stub_frame.sender(&dummy_map); // First is the deoptee frame
   deopt_sender = deopt_sender.sender(&dummy_map);     // Now deoptee caller
   // Compute the amount the oldest interpreter frame will have to adjust
   // its caller's stack by. If the caller is a compiled frame then
   // we pretend that the callee has no parameters so that the
   // extension counts for the full amount of locals and not just
   // locals-parms. This is because without a c2i adapter the parm
   // area as created by the compiled frame will not be usable by
   // the interpreter. (Depending on the calling convention there
   // may not even be enough space).
   // QQQ I'd rather see this pushed down into last_frame_adjust
   // and have it take the sender (aka caller).
   if (deopt_sender.is_compiled_frame()) {
     caller_adjustment = last_frame_adjust(0, callee_locals);
   } else if (callee_locals > callee_parameters) {
     // The caller frame may need extending to accommodate
     // non-parameter locals of the first unpacked interpreted frame.
     // Compute that adjustment.
     caller_adjustment = last_frame_adjust(callee_parameters, callee_locals);
   }
   // If the sender is deoptimized the we must retrieve the address of the handler
   // since the frame will "magically" show the original pc before the deopt
   // and we'd undo the deopt.
   frame_pcs[0] = deopt_sender.raw_pc();
   assert(CodeCache::find_blob_unsafe(frame_pcs[0]) != NULL, "bad pc");
   UnrollBlock* info = new UnrollBlock(array->frame_size() * BytesPerWord,
                                       caller_adjustment * BytesPerWord,
                                       number_of_frames,
                                       frame_sizes,
                                       frame_pcs,
                                       return_type);
 #if defined(IA32) || defined(AMD64)
   // We need a way to pass fp to the unpacking code so the skeletal frames
   // come out correct. This is only needed for x86 because of c2 using ebp
   // as an allocatable register. So this update is useless (and harmless)
   // on the other platforms. It would be nice to do this in a different
   // way but even the old style deoptimization had a problem with deriving
   // this value. NEEDS_CLEANUP
   // Note: now that c1 is using c2's deopt blob we must do this on all
   // x86 based platforms
   intptr_t** fp_addr = (intptr_t**) (((address)info) + info->initial_fp_offset_in_bytes());
   *fp_addr = array->sender().fp(); // was adapter_caller
 #endif /* IA32 || AMD64 */
   if (array->frames() > 1) {
     if (VerifyStack && TraceDeoptimization) {
       tty->print_cr("Deoptimizing method containing inlining");
     }
   }
   array->set_unroll_block(info);
   return info;
 }
 // Called to cleanup deoptimization data structures in normal case
 // after unpacking to stack and when stack overflow error occurs
 void Deoptimization::cleanup_deopt_info(JavaThread *thread,
                                         vframeArray *array) {
   // Get array if coming from exception
   if (array == NULL) {
     array = thread->vframe_array_head();
   }
   thread->set_vframe_array_head(NULL);
   // Free the previous UnrollBlock
   vframeArray* old_array = thread->vframe_array_last();
   thread->set_vframe_array_last(array);
   if (old_array != NULL) {
     UnrollBlock* old_info = old_array->unroll_block();
     old_array->set_unroll_block(NULL);
     delete old_info;
     delete old_array;
   }
   // Deallocate any resource creating in this routine and any ResourceObjs allocated
   // inside the vframeArray (StackValueCollections)
   delete thread->deopt_mark();
   thread->set_deopt_mark(NULL);
   if (JvmtiExport::can_pop_frame()) {
 #ifndef CC_INTERP
     // Regardless of whether we entered this routine with the pending
     // popframe condition bit set, we should always clear it now
     thread->clear_popframe_condition();
 #else
     // C++ interpeter will clear has_pending_popframe when it enters
     // with method_resume. For deopt_resume2 we clear it now.
     if (thread->popframe_forcing_deopt_reexecution())
         thread->clear_popframe_condition();
 #endif /* CC_INTERP */
   }
   // unpack_frames() is called at the end of the deoptimization handler
   // and (in C2) at the end of the uncommon trap handler. Note this fact
   // so that an asynchronous stack walker can work again. This counter is
   // incremented at the beginning of fetch_unroll_info() and (in C2) at
   // the beginning of uncommon_trap().
   thread->dec_in_deopt_handler();
 }
 // Return BasicType of value being returned
 JRT_LEAF(BasicType, Deoptimization::unpack_frames(JavaThread* thread, int exec_mode))
   // We are already active int he special DeoptResourceMark any ResourceObj's we
   // allocate will be freed at the end of the routine.
   // It is actually ok to allocate handles in a leaf method. It causes no safepoints,
   // but makes the entry a little slower. There is however a little dance we have to
   // do in debug mode to get around the NoHandleMark code in the JRT_LEAF macro
   ResetNoHandleMark rnhm; // No-op in release/product versions
   HandleMark hm;
   frame stub_frame = thread->last_frame();
   // Since the frame to unpack is the top frame of this thread, the vframe_array_head
   // must point to the vframeArray for the unpack frame.
   vframeArray* array = thread->vframe_array_head();
 #ifndef PRODUCT
   if (TraceDeoptimization) {
     tty->print_cr("DEOPT UNPACKING thread " INTPTR_FORMAT " vframeArray " INTPTR_FORMAT " mode %d", thread, array, exec_mode);
   }
 #endif
   UnrollBlock* info = array->unroll_block();
   // Unpack the interpreter frames and any adapter frame (c2 only) we might create.
   array->unpack_to_stack(stub_frame, exec_mode);
   BasicType bt = info->return_type();
   // If we have an exception pending, claim that the return type is an oop
   // so the deopt_blob does not overwrite the exception_oop.
   if (exec_mode == Unpack_exception)
     bt = T_OBJECT;
   // Cleanup thread deopt data
   cleanup_deopt_info(thread, array);
 #ifndef PRODUCT
   if (VerifyStack) {
     ResourceMark res_mark;
     // Verify that the just-unpacked frames match the interpreter's
     // notions of expression stack and locals
     vframeArray* cur_array = thread->vframe_array_last();
     RegisterMap rm(thread, false);
     rm.set_include_argument_oops(false);
     bool is_top_frame = true;
     int callee_size_of_parameters = 0;
     int callee_max_locals = 0;
     for (int i = 0; i < cur_array->frames(); i++) {
       vframeArrayElement* el = cur_array->element(i);
       frame* iframe = el->iframe();
       guarantee(iframe->is_interpreted_frame(), "Wrong frame type");
       // Get the oop map for this bci
       InterpreterOopMap mask;
       int cur_invoke_parameter_size = 0;
       bool try_next_mask = false;
       int next_mask_expression_stack_size = -1;
       int top_frame_expression_stack_adjustment = 0;
       methodHandle mh(thread, iframe->interpreter_frame_method());
       OopMapCache::compute_one_oop_map(mh, iframe->interpreter_frame_bci(), &mask);
       BytecodeStream str(mh);
       str.set_start(iframe->interpreter_frame_bci());
       int max_bci = mh->code_size();
       // Get to the next bytecode if possible
       assert(str.bci() < max_bci, "bci in interpreter frame out of bounds");
       // Check to see if we can grab the number of outgoing arguments
       // at an uncommon trap for an invoke (where the compiler
       // generates debug info before the invoke has executed)
       Bytecodes::Code cur_code = str.next();
       if (cur_code == Bytecodes::_invokevirtual ||
           cur_code == Bytecodes::_invokespecial ||
           cur_code == Bytecodes::_invokestatic  ||
           cur_code == Bytecodes::_invokeinterface) {
         Bytecode_invoke* invoke = Bytecode_invoke_at(mh, iframe->interpreter_frame_bci());
         symbolHandle signature(thread, invoke->signature());
         ArgumentSizeComputer asc(signature);
         cur_invoke_parameter_size = asc.size();
         if (cur_code != Bytecodes::_invokestatic) {
           // Add in receiver
           ++cur_invoke_parameter_size;
         }
       }
       if (str.bci() < max_bci) {
         Bytecodes::Code bc = str.next();
         if (bc >= 0) {
           // The interpreter oop map generator reports results before
           // the current bytecode has executed except in the case of
           // calls. It seems to be hard to tell whether the compiler
           // has emitted debug information matching the "state before"
           // a given bytecode or the state after, so we try both
           switch (cur_code) {
             case Bytecodes::_invokevirtual:
             case Bytecodes::_invokespecial:
             case Bytecodes::_invokestatic:
             case Bytecodes::_invokeinterface:
             case Bytecodes::_athrow:
               break;
             default: {
               InterpreterOopMap next_mask;
               OopMapCache::compute_one_oop_map(mh, str.bci(), &next_mask);
               next_mask_expression_stack_size = next_mask.expression_stack_size();
               // Need to subtract off the size of the result type of
               // the bytecode because this is not described in the
               // debug info but returned to the interpreter in the TOS
               // caching register
               BasicType bytecode_result_type = Bytecodes::result_type(cur_code);
               if (bytecode_result_type != T_ILLEGAL) {
                 top_frame_expression_stack_adjustment = type2size[bytecode_result_type];
               }
               assert(top_frame_expression_stack_adjustment >= 0, "");
               try_next_mask = true;
               break;
             }
           }
         }
       }
       // Verify stack depth and oops in frame
       // This assertion may be dependent on the platform we're running on and may need modification (tested on x86 and sparc)
       if (!(
             /* SPARC */
             (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_size_of_parameters) ||
             /* x86 */
             (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + callee_max_locals) ||
             (try_next_mask &&
              (iframe->interpreter_frame_expression_stack_size() == (next_mask_expression_stack_size -
                                                                     top_frame_expression_stack_adjustment))) ||
             (is_top_frame && (exec_mode == Unpack_exception) && iframe->interpreter_frame_expression_stack_size() == 0) ||
             (is_top_frame && (exec_mode == Unpack_uncommon_trap || exec_mode == Unpack_reexecute) &&
              (iframe->interpreter_frame_expression_stack_size() == mask.expression_stack_size() + cur_invoke_parameter_size))
             )) {
         ttyLocker ttyl;
         // Print out some information that will help us debug the problem
         tty->print_cr("Wrong number of expression stack elements during deoptimization");
         tty->print_cr("  Error occurred while verifying frame %d (0..%d, 0 is topmost)", i, cur_array->frames() - 1);
         tty->print_cr("  Fabricated interpreter frame had %d expression stack elements",
                       iframe->interpreter_frame_expression_stack_size());
         tty->print_cr("  Interpreter oop map had %d expression stack elements", mask.expression_stack_size());
         tty->print_cr("  try_next_mask = %d", try_next_mask);
         tty->print_cr("  next_mask_expression_stack_size = %d", next_mask_expression_stack_size);
         tty->print_cr("  callee_size_of_parameters = %d", callee_size_of_parameters);
         tty->print_cr("  callee_max_locals = %d", callee_max_locals);
         tty->print_cr("  top_frame_expression_stack_adjustment = %d", top_frame_expression_stack_adjustment);
         tty->print_cr("  exec_mode = %d", exec_mode);
         tty->print_cr("  cur_invoke_parameter_size = %d", cur_invoke_parameter_size);
         tty->print_cr("  Thread = " INTPTR_FORMAT ", thread ID = " UINTX_FORMAT, thread, thread->osthread()->thread_id());
         tty->print_cr("  Interpreted frames:");
         for (int k = 0; k < cur_array->frames(); k++) {
           vframeArrayElement* el = cur_array->element(k);
           tty->print_cr("    %s (bci %d)", el->method()->name_and_sig_as_C_string(), el->bci());
         }
         cur_array->print_on_2(tty);
         guarantee(false, "wrong number of expression stack elements during deopt");
       }
       VerifyOopClosure verify;
       iframe->oops_interpreted_do(&verify, &rm, false);
       callee_size_of_parameters = mh->size_of_parameters();
       callee_max_locals = mh->max_locals();
       is_top_frame = false;
     }
   }
 #endif /* !PRODUCT */
   return bt;
 JRT_END
 int Deoptimization::deoptimize_dependents() {
   Threads::deoptimized_wrt_marked_nmethods();
   return 0;
 }
 #ifdef COMPILER2
 bool Deoptimization::realloc_objects(JavaThread* thread, frame* fr, GrowableArray<ScopeValue*>* objects, TRAPS) {
   Handle pending_exception(thread->pending_exception());
   const char* exception_file = thread->exception_file();
   int exception_line = thread->exception_line();
   thread->clear_pending_exception();
   for (int i = 0; i < objects->length(); i++) {
     assert(objects->at(i)->is_object(), "invalid debug information");
     ObjectValue* sv = (ObjectValue*) objects->at(i);
     KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
     oop obj = NULL;
     if (k->oop_is_instance()) {
       instanceKlass* ik = instanceKlass::cast(k());
       obj = ik->allocate_instance(CHECK_(false));
     } else if (k->oop_is_typeArray()) {
       typeArrayKlass* ak = typeArrayKlass::cast(k());
       assert(sv->field_size() % type2size[ak->element_type()] == 0, "non-integral array length");
       int len = sv->field_size() / type2size[ak->element_type()];
       obj = ak->allocate(len, CHECK_(false));
     } else if (k->oop_is_objArray()) {
       objArrayKlass* ak = objArrayKlass::cast(k());
       obj = ak->allocate(sv->field_size(), CHECK_(false));
     }
     assert(obj != NULL, "allocation failed");
     assert(sv->value().is_null(), "redundant reallocation");
     sv->set_value(obj);
   }
   if (pending_exception.not_null()) {
     thread->set_pending_exception(pending_exception(), exception_file, exception_line);
   }
   return true;
 }
 // This assumes that the fields are stored in ObjectValue in the same order
 // they are yielded by do_nonstatic_fields.
 class FieldReassigner: public FieldClosure {
   frame* _fr;
   RegisterMap* _reg_map;
   ObjectValue* _sv;
   instanceKlass* _ik;
   oop _obj;
   int _i;
 public:
   FieldReassigner(frame* fr, RegisterMap* reg_map, ObjectValue* sv, oop obj) :
     _fr(fr), _reg_map(reg_map), _sv(sv), _obj(obj), _i(0) {}
   int i() const { return _i; }
   void do_field(fieldDescriptor* fd) {
     intptr_t val;
     StackValue* value =
       StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(i()));
     int offset = fd->offset();
     switch (fd->field_type()) {
     case T_OBJECT: case T_ARRAY:
       assert(value->type() == T_OBJECT, "Agreement.");
       _obj->obj_field_put(offset, value->get_obj()());
       break;
     case T_LONG: case T_DOUBLE: {
       assert(value->type() == T_INT, "Agreement.");
       StackValue* low =
         StackValue::create_stack_value(_fr, _reg_map, _sv->field_at(++_i));
 #ifdef _LP64
       jlong res = (jlong)low->get_int();
 #else
 #ifdef SPARC
       // For SPARC we have to swap high and low words.
       jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int());
 #else
       jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int());
 #endif //SPARC
 #endif
       _obj->long_field_put(offset, res);
       break;
     }
     // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem.
     case T_INT: case T_FLOAT: // 4 bytes.
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       _obj->int_field_put(offset, (jint)*((jint*)&val));
       break;
     case T_SHORT: case T_CHAR: // 2 bytes
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       _obj->short_field_put(offset, (jshort)*((jint*)&val));
       break;
     case T_BOOLEAN: case T_BYTE: // 1 byte
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       _obj->bool_field_put(offset, (jboolean)*((jint*)&val));
       break;
     default:
       ShouldNotReachHere();
     }
     _i++;
   }
 };
 // restore elements of an eliminated type array
 void Deoptimization::reassign_type_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, typeArrayOop obj, BasicType type) {
   int index = 0;
   intptr_t val;
   for (int i = 0; i < sv->field_size(); i++) {
     StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i));
     switch(type) {
     case T_LONG: case T_DOUBLE: {
       assert(value->type() == T_INT, "Agreement.");
       StackValue* low =
         StackValue::create_stack_value(fr, reg_map, sv->field_at(++i));
 #ifdef _LP64
       jlong res = (jlong)low->get_int();
 #else
 #ifdef SPARC
       // For SPARC we have to swap high and low words.
       jlong res = jlong_from((jint)low->get_int(), (jint)value->get_int());
 #else
       jlong res = jlong_from((jint)value->get_int(), (jint)low->get_int());
 #endif //SPARC
 #endif
       obj->long_at_put(index, res);
       break;
     }
     // Have to cast to INT (32 bits) pointer to avoid little/big-endian problem.
     case T_INT: case T_FLOAT: // 4 bytes.
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       obj->int_at_put(index, (jint)*((jint*)&val));
       break;
     case T_SHORT: case T_CHAR: // 2 bytes
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       obj->short_at_put(index, (jshort)*((jint*)&val));
       break;
     case T_BOOLEAN: case T_BYTE: // 1 byte
       assert(value->type() == T_INT, "Agreement.");
       val = value->get_int();
       obj->bool_at_put(index, (jboolean)*((jint*)&val));
       break;
       default:
         ShouldNotReachHere();
     }
     index++;
   }
 }
 // restore fields of an eliminated object array
 void Deoptimization::reassign_object_array_elements(frame* fr, RegisterMap* reg_map, ObjectValue* sv, objArrayOop obj) {
   for (int i = 0; i < sv->field_size(); i++) {
     StackValue* value = StackValue::create_stack_value(fr, reg_map, sv->field_at(i));
     assert(value->type() == T_OBJECT, "object element expected");
     obj->obj_at_put(i, value->get_obj()());
   }
 }
 // restore fields of all eliminated objects and arrays
 void Deoptimization::reassign_fields(frame* fr, RegisterMap* reg_map, GrowableArray<ScopeValue*>* objects) {
   for (int i = 0; i < objects->length(); i++) {
     ObjectValue* sv = (ObjectValue*) objects->at(i);
     KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
     Handle obj = sv->value();
     assert(obj.not_null(), "reallocation was missed");
     if (k->oop_is_instance()) {
       instanceKlass* ik = instanceKlass::cast(k());
       FieldReassigner reassign(fr, reg_map, sv, obj());
       ik->do_nonstatic_fields(&reassign);
     } else if (k->oop_is_typeArray()) {
       typeArrayKlass* ak = typeArrayKlass::cast(k());
       reassign_type_array_elements(fr, reg_map, sv, (typeArrayOop) obj(), ak->element_type());
     } else if (k->oop_is_objArray()) {
       reassign_object_array_elements(fr, reg_map, sv, (objArrayOop) obj());
     }
   }
 }
 // relock objects for which synchronization was eliminated
 void Deoptimization::relock_objects(frame* fr, RegisterMap* reg_map, GrowableArray<MonitorValue*>* monitors) {
   for (int i = 0; i < monitors->length(); i++) {
     MonitorValue* mv = monitors->at(i);
     StackValue* owner = StackValue::create_stack_value(fr, reg_map, mv->owner());
     if (mv->eliminated()) {
       Handle obj = owner->get_obj();
       assert(obj.not_null(), "reallocation was missed");
       BasicLock* lock = StackValue::resolve_monitor_lock(fr, mv->basic_lock());
       lock->set_displaced_header(obj->mark());
       obj->set_mark((markOop) lock);
     }
     assert(owner->get_obj()->is_locked(), "object must be locked now");
   }
 }
 #ifndef PRODUCT
 // print information about reallocated objects
 void Deoptimization::print_objects(GrowableArray<ScopeValue*>* objects) {
   fieldDescriptor fd;
   for (int i = 0; i < objects->length(); i++) {
     ObjectValue* sv = (ObjectValue*) objects->at(i);
     KlassHandle k(((ConstantOopReadValue*) sv->klass())->value()());
     Handle obj = sv->value();
     tty->print("     object <" INTPTR_FORMAT "> of type ", sv->value()());
     k->as_klassOop()->print_value();
     tty->print(" allocated (%d bytes)", obj->size() * HeapWordSize);
     tty->cr();
     if (Verbose) {
       k->oop_print_on(obj(), tty);
     }
   }
 }
 #endif
 #endif // COMPILER2
 vframeArray* Deoptimization::create_vframeArray(JavaThread* thread, frame fr, RegisterMap *reg_map, GrowableArray<compiledVFrame*>* chunk) {
 #ifndef PRODUCT
   if (TraceDeoptimization) {
     ttyLocker ttyl;
     tty->print("DEOPT PACKING thread " INTPTR_FORMAT " ", thread);
     fr.print_on(tty);
     tty->print_cr("     Virtual frames (innermost first):");
     for (int index = 0; index < chunk->length(); index++) {
       compiledVFrame* vf = chunk->at(index);
       tty->print("       %2d - ", index);
       vf->print_value();
       int bci = chunk->at(index)->raw_bci();
       const char* code_name;
       if (bci == SynchronizationEntryBCI) {
         code_name = "sync entry";
       } else {
         Bytecodes::Code code = Bytecodes::code_at(vf->method(), bci);
         code_name = Bytecodes::name(code);
       }
       tty->print(" - %s", code_name);
       tty->print_cr(" @ bci %d ", bci);
       if (Verbose) {
         vf->print();
         tty->cr();
       }
     }
   }
 #endif
   // Register map for next frame (used for stack crawl).  We capture
   // the state of the deopt'ing frame's caller.  Thus if we need to
   // stuff a C2I adapter we can properly fill in the callee-save
   // register locations.
   frame caller = fr.sender(reg_map);
   int frame_size = caller.sp() - fr.sp();
   frame sender = caller;
   // Since the Java thread being deoptimized will eventually adjust it's own stack,
   // the vframeArray containing the unpacking information is allocated in the C heap.
   // For Compiler1, the caller of the deoptimized frame is saved for use by unpack_frames().
   vframeArray* array = vframeArray::allocate(thread, frame_size, chunk, reg_map, sender, caller, fr);
   // Compare the vframeArray to the collected vframes
   assert(array->structural_compare(thread, chunk), "just checking");
   Events::log("# vframes = %d", (intptr_t)chunk->length());
 #ifndef PRODUCT
   if (TraceDeoptimization) {
     ttyLocker ttyl;
     tty->print_cr("     Created vframeArray " INTPTR_FORMAT, array);
     if (Verbose) {
       int count = 0;
       // this used to leak deoptimizedVFrame like it was going out of style!!!
       for (int index = 0; index < array->frames(); index++ ) {
         vframeArrayElement* e = array->element(index);
         e->print(tty);
         /*
           No printing yet.
         array->vframe_at(index)->print_activation(count++);
         // better as...
         array->print_activation_for(index, count++);
         */
       }
     }
   }
 #endif // PRODUCT
   return array;
 }
 static void collect_monitors(compiledVFrame* cvf, GrowableArray<Handle>* objects_to_revoke) {
   GrowableArray<MonitorInfo*>* monitors = cvf->monitors();
   for (int i = 0; i < monitors->length(); i++) {
     MonitorInfo* mon_info = monitors->at(i);
     if (mon_info->owner() != NULL) {
       objects_to_revoke->append(Handle(mon_info->owner()));
     }
   }
 }
 void Deoptimization::revoke_biases_of_monitors(JavaThread* thread, frame fr, RegisterMap* map) {
   if (!UseBiasedLocking) {
     return;
   }
   GrowableArray<Handle>* objects_to_revoke = new GrowableArray<Handle>();
   // Unfortunately we don't have a RegisterMap available in most of
   // the places we want to call this routine so we need to walk the
   // stack again to update the register map.
   if (map == NULL || !map->update_map()) {
     StackFrameStream sfs(thread, true);
     bool found = false;
     while (!found && !sfs.is_done()) {
       frame* cur = sfs.current();
       sfs.next();
       found = cur->id() == fr.id();
     }
     assert(found, "frame to be deoptimized not found on target thread's stack");
     map = sfs.register_map();
   }
   vframe* vf = vframe::new_vframe(&fr, map, thread);
   compiledVFrame* cvf = compiledVFrame::cast(vf);
   // Revoke monitors' biases in all scopes
   while (!cvf->is_top()) {
     collect_monitors(cvf, objects_to_revoke);
     cvf = compiledVFrame::cast(cvf->sender());
   }
   collect_monitors(cvf, objects_to_revoke);
   if (SafepointSynchronize::is_at_safepoint()) {
     BiasedLocking::revoke_at_safepoint(objects_to_revoke);
   } else {
     BiasedLocking::revoke(objects_to_revoke);
   }
 }
 void Deoptimization::revoke_biases_of_monitors(CodeBlob* cb) {
   if (!UseBiasedLocking) {
     return;
   }
   assert(SafepointSynchronize::is_at_safepoint(), "must only be called from safepoint");
   GrowableArray<Handle>* objects_to_revoke = new GrowableArray<Handle>();
   for (JavaThread* jt = Threads::first(); jt != NULL ; jt = jt->next()) {
     if (jt->has_last_Java_frame()) {
       StackFrameStream sfs(jt, true);
       while (!sfs.is_done()) {
         frame* cur = sfs.current();
         if (cb->contains(cur->pc())) {
           vframe* vf = vframe::new_vframe(cur, sfs.register_map(), jt);
           compiledVFrame* cvf = compiledVFrame::cast(vf);
           // Revoke monitors' biases in all scopes
           while (!cvf->is_top()) {
             collect_monitors(cvf, objects_to_revoke);
             cvf = compiledVFrame::cast(cvf->sender());
           }
           collect_monitors(cvf, objects_to_revoke);
         }
         sfs.next();
       }
     }
   }
   BiasedLocking::revoke_at_safepoint(objects_to_revoke);
 }
 void Deoptimization::deoptimize_single_frame(JavaThread* thread, frame fr) {
   assert(fr.can_be_deoptimized(), "checking frame type");
   gather_statistics(Reason_constraint, Action_none, Bytecodes::_illegal);
   EventMark m("Deoptimization (pc=" INTPTR_FORMAT ", sp=" INTPTR_FORMAT ")", fr.pc(), fr.id());
   // Patch the nmethod so that when execution returns to it we will
   // deopt the execution state and return to the interpreter.
   fr.deoptimize(thread);
 }
 void Deoptimization::deoptimize(JavaThread* thread, frame fr, RegisterMap *map) {
   // Deoptimize only if the frame comes from compile code.
   // Do not deoptimize the frame which is already patched
   // during the execution of the loops below.
   if (!fr.is_compiled_frame() || fr.is_deoptimized_frame()) {
     return;
   }
   ResourceMark rm;
   DeoptimizationMarker dm;
   if (UseBiasedLocking) {
     revoke_biases_of_monitors(thread, fr, map);
   }
   deoptimize_single_frame(thread, fr);
 }
 void Deoptimization::deoptimize_frame(JavaThread* thread, intptr_t* id) {
   // Compute frame and register map based on thread and sp.
   RegisterMap reg_map(thread, UseBiasedLocking);
   frame fr = thread->last_frame();
   while (fr.id() != id) {
     fr = fr.sender(&reg_map);
   }
   deoptimize(thread, fr, &reg_map);
 }
 // JVMTI PopFrame support
 JRT_LEAF(void, Deoptimization::popframe_preserve_args(JavaThread* thread, int bytes_to_save, void* start_address))
 {
   thread->popframe_preserve_args(in_ByteSize(bytes_to_save), start_address);
 }
 JRT_END
 #ifdef COMPILER2
 void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index, TRAPS) {
   // in case of an unresolved klass entry, load the class.
   if (constant_pool->tag_at(index).is_unresolved_klass()) {
     klassOop tk = constant_pool->klass_at(index, CHECK);
     return;
   }
   if (!constant_pool->tag_at(index).is_symbol()) return;
   Handle class_loader (THREAD, instanceKlass::cast(constant_pool->pool_holder())->class_loader());
   symbolHandle symbol (THREAD, constant_pool->symbol_at(index));
   // class name?
   if (symbol->byte_at(0) != '(') {
     Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain());
     SystemDictionary::resolve_or_null(symbol, class_loader, protection_domain, CHECK);
     return;
   }
   // then it must be a signature!
   for (SignatureStream ss(symbol); !ss.is_done(); ss.next()) {
     if (ss.is_object()) {
       symbolOop s = ss.as_symbol(CHECK);
       symbolHandle class_name (THREAD, s);
       Handle protection_domain (THREAD, Klass::cast(constant_pool->pool_holder())->protection_domain());
       SystemDictionary::resolve_or_null(class_name, class_loader, protection_domain, CHECK);
     }
   }
 }
 void Deoptimization::load_class_by_index(constantPoolHandle constant_pool, int index) {
   EXCEPTION_MARK;
   load_class_by_index(constant_pool, index, THREAD);
   if (HAS_PENDING_EXCEPTION) {
     // Exception happened during classloading. We ignore the exception here, since it
     // is going to be rethrown since the current activation is going to be deoptimzied and
     // the interpreter will re-execute the bytecode.
     CLEAR_PENDING_EXCEPTION;
   }
 }
 JRT_ENTRY(void, Deoptimization::uncommon_trap_inner(JavaThread* thread, jint trap_request)) {
   HandleMark hm;
   // uncommon_trap() is called at the beginning of the uncommon trap
   // handler. Note this fact before we start generating temporary frames
   // that can confuse an asynchronous stack walker. This counter is
   // decremented at the end of unpack_frames().
   thread->inc_in_deopt_handler();
   // We need to update the map if we have biased locking.
   RegisterMap reg_map(thread, UseBiasedLocking);
   frame stub_frame = thread->last_frame();
   frame fr = stub_frame.sender(&reg_map);
   // Make sure the calling nmethod is not getting deoptimized and removed
   // before we are done with it.
   nmethodLocker nl(fr.pc());
   {
     ResourceMark rm;
     // Revoke biases of any monitors in the frame to ensure we can migrate them
     revoke_biases_of_monitors(thread, fr, &reg_map);
     DeoptReason reason = trap_request_reason(trap_request);
     DeoptAction action = trap_request_action(trap_request);
     jint unloaded_class_index = trap_request_index(trap_request); // CP idx or -1
     Events::log("Uncommon trap occurred @" INTPTR_FORMAT " unloaded_class_index = %d", fr.pc(), (int) trap_request);
     vframe*  vf  = vframe::new_vframe(&fr, &reg_map, thread);
     compiledVFrame* cvf = compiledVFrame::cast(vf);
     nmethod* nm = cvf->code();
     ScopeDesc*      trap_scope  = cvf->scope();
     methodHandle    trap_method = trap_scope->method();
     int             trap_bci    = trap_scope->bci();
     Bytecodes::Code trap_bc     = Bytecode_at(trap_method->bcp_from(trap_bci))->java_code();
     // Record this event in the histogram.
     gather_statistics(reason, action, trap_bc);
     // Ensure that we can record deopt. history:
     bool create_if_missing = ProfileTraps;
     methodDataHandle trap_mdo
       (THREAD, get_method_data(thread, trap_method, create_if_missing));
     // Print a bunch of diagnostics, if requested.
     if (TraceDeoptimization || LogCompilation) {
       ResourceMark rm;
       ttyLocker ttyl;
       char buf[100];
       if (xtty != NULL) {
         xtty->begin_head("uncommon_trap thread='" UINTX_FORMAT"' %s",
                          os::current_thread_id(),
                          format_trap_request(buf, sizeof(buf), trap_request));
         nm->log_identity(xtty);
       }
       symbolHandle class_name;
       bool unresolved = false;
       if (unloaded_class_index >= 0) {
         constantPoolHandle constants (THREAD, trap_method->constants());
         if (constants->tag_at(unloaded_class_index).is_unresolved_klass()) {
           class_name = symbolHandle(THREAD,
             constants->klass_name_at(unloaded_class_index));
           unresolved = true;
           if (xtty != NULL)
             xtty->print(" unresolved='1'");
         } else if (constants->tag_at(unloaded_class_index).is_symbol()) {
           class_name = symbolHandle(THREAD,
             constants->symbol_at(unloaded_class_index));
         }
         if (xtty != NULL)
           xtty->name(class_name);
       }
       if (xtty != NULL && trap_mdo.not_null()) {
         // Dump the relevant MDO state.
         // This is the deopt count for the current reason, any previous
         // reasons or recompiles seen at this point.
         int dcnt = trap_mdo->trap_count(reason);
         if (dcnt != 0)
           xtty->print(" count='%d'", dcnt);
         ProfileData* pdata = trap_mdo->bci_to_data(trap_bci);
         int dos = (pdata == NULL)? 0: pdata->trap_state();
         if (dos != 0) {
           xtty->print(" state='%s'", format_trap_state(buf, sizeof(buf), dos));
           if (trap_state_is_recompiled(dos)) {
             int recnt2 = trap_mdo->overflow_recompile_count();
             if (recnt2 != 0)
               xtty->print(" recompiles2='%d'", recnt2);
           }
         }
       }
       if (xtty != NULL) {
         xtty->stamp();
         xtty->end_head();
       }
       if (TraceDeoptimization) {  // make noise on the tty
         tty->print("Uncommon trap occurred in");
         nm->method()->print_short_name(tty);
         tty->print(" (@" INTPTR_FORMAT ") thread=%d reason=%s action=%s unloaded_class_index=%d",
                    fr.pc(),
                    (int) os::current_thread_id(),
                    trap_reason_name(reason),
                    trap_action_name(action),
                    unloaded_class_index);
         if (class_name.not_null()) {
           tty->print(unresolved ? " unresolved class: " : " symbol: ");
           class_name->print_symbol_on(tty);
         }
         tty->cr();
       }
       if (xtty != NULL) {
         // Log the precise location of the trap.
         for (ScopeDesc* sd = trap_scope; ; sd = sd->sender()) {
           xtty->begin_elem("jvms bci='%d'", sd->bci());
           xtty->method(sd->method());
           xtty->end_elem();
           if (sd->is_top())  break;
         }
         xtty->tail("uncommon_trap");
       }
     }
     // (End diagnostic printout.)
     // Load class if necessary
     if (unloaded_class_index >= 0) {
       constantPoolHandle constants(THREAD, trap_method->constants());
       load_class_by_index(constants, unloaded_class_index);
     }
     // Flush the nmethod if necessary and desirable.
     //
     // We need to avoid situations where we are re-flushing the nmethod
     // because of a hot deoptimization site.  Repeated flushes at the same
     // point need to be detected by the compiler and avoided.  If the compiler
     // cannot avoid them (or has a bug and "refuses" to avoid them), this
     // module must take measures to avoid an infinite cycle of recompilation
     // and deoptimization.  There are several such measures:
     //
     //   1. If a recompilation is ordered a second time at some site X
     //   and for the same reason R, the action is adjusted to 'reinterpret',
     //   to give the interpreter time to exercise the method more thoroughly.
     //   If this happens, the method's overflow_recompile_count is incremented.
     //
     //   2. If the compiler fails to reduce the deoptimization rate, then
     //   the method's overflow_recompile_count will begin to exceed the set
     //   limit PerBytecodeRecompilationCutoff.  If this happens, the action
     //   is adjusted to 'make_not_compilable', and the method is abandoned
     //   to the interpreter.  This is a performance hit for hot methods,
     //   but is better than a disastrous infinite cycle of recompilations.
     //   (Actually, only the method containing the site X is abandoned.)
     //
     //   3. In parallel with the previous measures, if the total number of
     //   recompilations of a method exceeds the much larger set limit
     //   PerMethodRecompilationCutoff, the method is abandoned.
     //   This should only happen if the method is very large and has
     //   many "lukewarm" deoptimizations.  The code which enforces this
     //   limit is elsewhere (class nmethod, class methodOopDesc).
     //
     // Note that the per-BCI 'is_recompiled' bit gives the compiler one chance
     // to recompile at each bytecode independently of the per-BCI cutoff.
     //
     // The decision to update code is up to the compiler, and is encoded
     // in the Action_xxx code.  If the compiler requests Action_none
     // no trap state is changed, no compiled code is changed, and the
     // computation suffers along in the interpreter.
     //
     // The other action codes specify various tactics for decompilation
     // and recompilation.  Action_maybe_recompile is the loosest, and
     // allows the compiled code to stay around until enough traps are seen,
     // and until the compiler gets around to recompiling the trapping method.
     //
     // The other actions cause immediate removal of the present code.
     bool update_trap_state = true;
     bool make_not_entrant = false;
     bool make_not_compilable = false;
     bool reset_counters = false;
     switch (action) {
     case Action_none:
       // Keep the old code.
       update_trap_state = false;
       break;
     case Action_maybe_recompile:
       // Do not need to invalidate the present code, but we can
       // initiate another
       // Start compiler without (necessarily) invalidating the nmethod.
       // The system will tolerate the old code, but new code should be
       // generated when possible.
       break;
     case Action_reinterpret:
       // Go back into the interpreter for a while, and then consider
       // recompiling form scratch.
       make_not_entrant = true;
       // Reset invocation counter for outer most method.
       // This will allow the interpreter to exercise the bytecodes
       // for a while before recompiling.
       // By contrast, Action_make_not_entrant is immediate.
       //
       // Note that the compiler will track null_check, null_assert,
       // range_check, and class_check events and log them as if they
       // had been traps taken from compiled code.  This will update
       // the MDO trap history so that the next compilation will
       // properly detect hot trap sites.
       reset_counters = true;
       break;
     case Action_make_not_entrant:
       // Request immediate recompilation, and get rid of the old code.
       // Make them not entrant, so next time they are called they get
       // recompiled.  Unloaded classes are loaded now so recompile before next
       // time they are called.  Same for uninitialized.  The interpreter will
       // link the missing class, if any.
       make_not_entrant = true;
       break;
     case Action_make_not_compilable:
       // Give up on compiling this method at all.
       make_not_entrant = true;
       make_not_compilable = true;
       break;
     default:
       ShouldNotReachHere();
     }
     // Setting +ProfileTraps fixes the following, on all platforms:
     // 4852688: ProfileInterpreter is off by default for ia64.  The result is
     // infinite heroic-opt-uncommon-trap/deopt/recompile cycles, since the
     // recompile relies on a methodDataOop to record heroic opt failures.
     // Whether the interpreter is producing MDO data or not, we also need
     // to use the MDO to detect hot deoptimization points and control
     // aggressive optimization.
     if (ProfileTraps && update_trap_state && trap_mdo.not_null()) {
       assert(trap_mdo() == get_method_data(thread, trap_method, false), "sanity");
       uint this_trap_count = 0;
       bool maybe_prior_trap = false;
       bool maybe_prior_recompile = false;
       ProfileData* pdata
         = query_update_method_data(trap_mdo, trap_bci, reason,
                                    //outputs:
                                    this_trap_count,
                                    maybe_prior_trap,
                                    maybe_prior_recompile);
       // Because the interpreter also counts null, div0, range, and class
       // checks, these traps from compiled code are double-counted.
       // This is harmless; it just means that the PerXTrapLimit values
       // are in effect a little smaller than they look.
       DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason);
       if (per_bc_reason != Reason_none) {
         // Now take action based on the partially known per-BCI history.
         if (maybe_prior_trap
             && this_trap_count >= (uint)PerBytecodeTrapLimit) {
           // If there are too many traps at this BCI, force a recompile.
           // This will allow the compiler to see the limit overflow, and
           // take corrective action, if possible.  The compiler generally
           // does not use the exact PerBytecodeTrapLimit value, but instead
           // changes its tactics if it sees any traps at all.  This provides
           // a little hysteresis, delaying a recompile until a trap happens
           // several times.
           //
           // Actually, since there is only one bit of counter per BCI,
           // the possible per-BCI counts are {0,1,(per-method count)}.
           // This produces accurate results if in fact there is only
           // one hot trap site, but begins to get fuzzy if there are
           // many sites.  For example, if there are ten sites each
           // trapping two or more times, they each get the blame for
           // all of their traps.
           make_not_entrant = true;
         }
         // Detect repeated recompilation at the same BCI, and enforce a limit.
         if (make_not_entrant && maybe_prior_recompile) {
           // More than one recompile at this point.
           trap_mdo->inc_overflow_recompile_count();
           if (maybe_prior_trap
               && ((uint)trap_mdo->overflow_recompile_count()
                   > (uint)PerBytecodeRecompilationCutoff)) {
             // Give up on the method containing the bad BCI.
             if (trap_method() == nm->method()) {
               make_not_compilable = true;
             } else {
               trap_method->set_not_compilable();
               // But give grace to the enclosing nm->method().
             }
           }
         }
       } else {
         // For reasons which are not recorded per-bytecode, we simply
         // force recompiles unconditionally.
         // (Note that PerMethodRecompilationCutoff is enforced elsewhere.)
         make_not_entrant = true;
       }
       // Go back to the compiler if there are too many traps in this method.
       if (this_trap_count >= (uint)PerMethodTrapLimit) {
         // If there are too many traps in this method, force a recompile.
         // This will allow the compiler to see the limit overflow, and
         // take corrective action, if possible.
         // (This condition is an unlikely backstop only, because the
         // PerBytecodeTrapLimit is more likely to take effect first,
         // if it is applicable.)
         make_not_entrant = true;
       }
       // Here's more hysteresis:  If there has been a recompile at
       // this trap point already, run the method in the interpreter
       // for a while to exercise it more thoroughly.
       if (make_not_entrant && maybe_prior_recompile && maybe_prior_trap) {
         reset_counters = true;
       }
       if (make_not_entrant && pdata != NULL) {
         // Record the recompilation event, if any.
         int tstate0 = pdata->trap_state();
         int tstate1 = trap_state_set_recompiled(tstate0, true);
         if (tstate1 != tstate0)
           pdata->set_trap_state(tstate1);
       }
     }
     // Take requested actions on the method:
     // Reset invocation counters
     if (reset_counters) {
       if (nm->is_osr_method())
         reset_invocation_counter(trap_scope, CompileThreshold);
       else
         reset_invocation_counter(trap_scope);
     }
     // Recompile
     if (make_not_entrant) {
       nm->make_not_entrant();
     }
     // Give up compiling
     if (make_not_compilable) {
       assert(make_not_entrant, "consistent");
       nm->method()->set_not_compilable();
     }
   } // Free marked resources
 }
 JRT_END
 methodDataOop
 Deoptimization::get_method_data(JavaThread* thread, methodHandle m,
                                 bool create_if_missing) {
   Thread* THREAD = thread;
   methodDataOop mdo = m()->method_data();
   if (mdo == NULL && create_if_missing && !HAS_PENDING_EXCEPTION) {
     // Build an MDO.  Ignore errors like OutOfMemory;
     // that simply means we won't have an MDO to update.
     methodOopDesc::build_interpreter_method_data(m, THREAD);
     if (HAS_PENDING_EXCEPTION) {
       assert((PENDING_EXCEPTION->is_a(SystemDictionary::OutOfMemoryError_klass())), "we expect only an OOM error here");
       CLEAR_PENDING_EXCEPTION;
     }
     mdo = m()->method_data();
   }
   return mdo;
 }
 ProfileData*
 Deoptimization::query_update_method_data(methodDataHandle trap_mdo,
                                          int trap_bci,
                                          Deoptimization::DeoptReason reason,
                                          //outputs:
                                          uint& ret_this_trap_count,
                                          bool& ret_maybe_prior_trap,
                                          bool& ret_maybe_prior_recompile) {
   uint prior_trap_count = trap_mdo->trap_count(reason);
   uint this_trap_count  = trap_mdo->inc_trap_count(reason);
   // If the runtime cannot find a place to store trap history,
   // it is estimated based on the general condition of the method.
   // If the method has ever been recompiled, or has ever incurred
   // a trap with the present reason , then this BCI is assumed
   // (pessimistically) to be the culprit.
   bool maybe_prior_trap      = (prior_trap_count != 0);
   bool maybe_prior_recompile = (trap_mdo->decompile_count() != 0);
   ProfileData* pdata = NULL;
   // For reasons which are recorded per bytecode, we check per-BCI data.
   DeoptReason per_bc_reason = reason_recorded_per_bytecode_if_any(reason);
   if (per_bc_reason != Reason_none) {
     // Find the profile data for this BCI.  If there isn't one,
     // try to allocate one from the MDO's set of spares.
     // This will let us detect a repeated trap at this point.
     pdata = trap_mdo->allocate_bci_to_data(trap_bci);
     if (pdata != NULL) {
       // Query the trap state of this profile datum.
       int tstate0 = pdata->trap_state();
       if (!trap_state_has_reason(tstate0, per_bc_reason))
         maybe_prior_trap = false;
       if (!trap_state_is_recompiled(tstate0))
         maybe_prior_recompile = false;
       // Update the trap state of this profile datum.
       int tstate1 = tstate0;
       // Record the reason.
       tstate1 = trap_state_add_reason(tstate1, per_bc_reason);
       // Store the updated state on the MDO, for next time.
       if (tstate1 != tstate0)
         pdata->set_trap_state(tstate1);
     } else {
       if (LogCompilation && xtty != NULL)
         // Missing MDP?  Leave a small complaint in the log.
         xtty->elem("missing_mdp bci='%d'", trap_bci);
     }
   }
   // Return results:
   ret_this_trap_count = this_trap_count;
   ret_maybe_prior_trap = maybe_prior_trap;
   ret_maybe_prior_recompile = maybe_prior_recompile;
   return pdata;
 }
 void
 Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) {
   ResourceMark rm;
   // Ignored outputs:
   uint ignore_this_trap_count;
   bool ignore_maybe_prior_trap;
   bool ignore_maybe_prior_recompile;
   query_update_method_data(trap_mdo, trap_bci,
                            (DeoptReason)reason,
                            ignore_this_trap_count,
                            ignore_maybe_prior_trap,
                            ignore_maybe_prior_recompile);
 }
 void Deoptimization::reset_invocation_counter(ScopeDesc* trap_scope, jint top_count) {
   ScopeDesc* sd = trap_scope;
   for (; !sd->is_top(); sd = sd->sender()) {
     // Reset ICs of inlined methods, since they can trigger compilations also.
     sd->method()->invocation_counter()->reset();
   }
   InvocationCounter* c = sd->method()->invocation_counter();
   if (top_count != _no_count) {
     // It was an OSR method, so bump the count higher.
     c->set(c->state(), top_count);
   } else {
     c->reset();
   }
   sd->method()->backedge_counter()->reset();
 }
 Deoptimization::UnrollBlock* Deoptimization::uncommon_trap(JavaThread* thread, jint trap_request) {
   // Still in Java no safepoints
   {
     // This enters VM and may safepoint
     uncommon_trap_inner(thread, trap_request);
   }
   return fetch_unroll_info_helper(thread);
 }
 // Local derived constants.
 // Further breakdown of DataLayout::trap_state, as promised by DataLayout.
 const int DS_REASON_MASK   = DataLayout::trap_mask >> 1;
 const int DS_RECOMPILE_BIT = DataLayout::trap_mask - DS_REASON_MASK;
 //---------------------------trap_state_reason---------------------------------
 Deoptimization::DeoptReason
 Deoptimization::trap_state_reason(int trap_state) {
   // This assert provides the link between the width of DataLayout::trap_bits
   // and the encoding of "recorded" reasons.  It ensures there are enough
   // bits to store all needed reasons in the per-BCI MDO profile.
   assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits");
   int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
   trap_state -= recompile_bit;
   if (trap_state == DS_REASON_MASK) {
     return Reason_many;
   } else {
     assert((int)Reason_none == 0, "state=0 => Reason_none");
     return (DeoptReason)trap_state;
   }
 }
 //-------------------------trap_state_has_reason-------------------------------
 int Deoptimization::trap_state_has_reason(int trap_state, int reason) {
   assert(reason_is_recorded_per_bytecode((DeoptReason)reason), "valid reason");
   assert(DS_REASON_MASK >= Reason_RECORDED_LIMIT, "enough bits");
   int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
   trap_state -= recompile_bit;
   if (trap_state == DS_REASON_MASK) {
     return -1;  // true, unspecifically (bottom of state lattice)
   } else if (trap_state == reason) {
     return 1;   // true, definitely
   } else if (trap_state == 0) {
     return 0;   // false, definitely (top of state lattice)
   } else {
     return 0;   // false, definitely
   }
 }
 //-------------------------trap_state_add_reason-------------------------------
 int Deoptimization::trap_state_add_reason(int trap_state, int reason) {
   assert(reason_is_recorded_per_bytecode((DeoptReason)reason) || reason == Reason_many, "valid reason");
   int recompile_bit = (trap_state & DS_RECOMPILE_BIT);
   trap_state -= recompile_bit;
   if (trap_state == DS_REASON_MASK) {
     return trap_state + recompile_bit;     // already at state lattice bottom
   } else if (trap_state == reason) {
     return trap_state + recompile_bit;     // the condition is already true
   } else if (trap_state == 0) {
     return reason + recompile_bit;          // no condition has yet been true
   } else {
     return DS_REASON_MASK + recompile_bit;  // fall to state lattice bottom
   }
 }
 //-----------------------trap_state_is_recompiled------------------------------
 bool Deoptimization::trap_state_is_recompiled(int trap_state) {
   return (trap_state & DS_RECOMPILE_BIT) != 0;
 }
 //-----------------------trap_state_set_recompiled-----------------------------
 int Deoptimization::trap_state_set_recompiled(int trap_state, bool z) {
   if (z)  return trap_state |  DS_RECOMPILE_BIT;
   else    return trap_state & ~DS_RECOMPILE_BIT;
 }
 //---------------------------format_trap_state---------------------------------
 // This is used for debugging and diagnostics, including hotspot.log output.
 const char* Deoptimization::format_trap_state(char* buf, size_t buflen,
                                               int trap_state) {
   DeoptReason reason      = trap_state_reason(trap_state);
   bool        recomp_flag = trap_state_is_recompiled(trap_state);
   // Re-encode the state from its decoded components.
   int decoded_state = 0;
   if (reason_is_recorded_per_bytecode(reason) || reason == Reason_many)
     decoded_state = trap_state_add_reason(decoded_state, reason);
   if (recomp_flag)
     decoded_state = trap_state_set_recompiled(decoded_state, recomp_flag);
   // If the state re-encodes properly, format it symbolically.
   // Because this routine is used for debugging and diagnostics,
   // be robust even if the state is a strange value.
   size_t len;
   if (decoded_state != trap_state) {
     // Random buggy state that doesn't decode??
     len = jio_snprintf(buf, buflen, "#%d", trap_state);
   } else {
     len = jio_snprintf(buf, buflen, "%s%s",
                        trap_reason_name(reason),
                        recomp_flag ? " recompiled" : "");
   }
   if (len >= buflen)
     buf[buflen-1] = '\0';
   return buf;
 }
 //--------------------------------statics--------------------------------------
 Deoptimization::DeoptAction Deoptimization::_unloaded_action
   = Deoptimization::Action_reinterpret;
 const char* Deoptimization::_trap_reason_name[Reason_LIMIT] = {
   // Note:  Keep this in sync. with enum DeoptReason.
   "none",
   "null_check",
   "null_assert",
   "range_check",
   "class_check",
   "array_check",
   "intrinsic",
   "unloaded",
   "uninitialized",
   "unreached",
   "unhandled",
   "constraint",
   "div0_check",
   "age"
 };
 const char* Deoptimization::_trap_action_name[Action_LIMIT] = {
   // Note:  Keep this in sync. with enum DeoptAction.
   "none",
   "maybe_recompile",
   "reinterpret",
   "make_not_entrant",
   "make_not_compilable"
 };
 const char* Deoptimization::trap_reason_name(int reason) {
   if (reason == Reason_many)  return "many";
   if ((uint)reason < Reason_LIMIT)
     return _trap_reason_name[reason];
   static char buf[20];
   sprintf(buf, "reason%d", reason);
   return buf;
 }
 const char* Deoptimization::trap_action_name(int action) {
   if ((uint)action < Action_LIMIT)
     return _trap_action_name[action];
   static char buf[20];
   sprintf(buf, "action%d", action);
   return buf;
 }
 // This is used for debugging and diagnostics, including hotspot.log output.
 const char* Deoptimization::format_trap_request(char* buf, size_t buflen,
                                                 int trap_request) {
   jint unloaded_class_index = trap_request_index(trap_request);
   const char* reason = trap_reason_name(trap_request_reason(trap_request));
   const char* action = trap_action_name(trap_request_action(trap_request));
   size_t len;
   if (unloaded_class_index < 0) {
     len = jio_snprintf(buf, buflen, "reason='%s' action='%s'",
                        reason, action);
   } else {
     len = jio_snprintf(buf, buflen, "reason='%s' action='%s' index='%d'",
                        reason, action, unloaded_class_index);
   }
   if (len >= buflen)
     buf[buflen-1] = '\0';
   return buf;
 }
 juint Deoptimization::_deoptimization_hist
         [Deoptimization::Reason_LIMIT]
     [1 + Deoptimization::Action_LIMIT]
         [Deoptimization::BC_CASE_LIMIT]
   = {0};
 enum {
   LSB_BITS = 8,
   LSB_MASK = right_n_bits(LSB_BITS)
 };
 void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action,
                                        Bytecodes::Code bc) {
   assert(reason >= 0 && reason < Reason_LIMIT, "oob");
   assert(action >= 0 && action < Action_LIMIT, "oob");
   _deoptimization_hist[Reason_none][0][0] += 1;  // total
   _deoptimization_hist[reason][0][0]      += 1;  // per-reason total
   juint* cases = _deoptimization_hist[reason][1+action];
   juint* bc_counter_addr = NULL;
   juint  bc_counter      = 0;
   // Look for an unused counter, or an exact match to this BC.
   if (bc != Bytecodes::_illegal) {
     for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) {
       juint* counter_addr = &cases[bc_case];
       juint  counter = *counter_addr;
       if ((counter == 0 && bc_counter_addr == NULL)
           || (Bytecodes::Code)(counter & LSB_MASK) == bc) {
         // this counter is either free or is already devoted to this BC
         bc_counter_addr = counter_addr;
         bc_counter = counter | bc;
       }
     }
   }
   if (bc_counter_addr == NULL) {
     // Overflow, or no given bytecode.
     bc_counter_addr = &cases[BC_CASE_LIMIT-1];
     bc_counter = (*bc_counter_addr & ~LSB_MASK);  // clear LSB
   }
   *bc_counter_addr = bc_counter + (1 << LSB_BITS);
 }
 jint Deoptimization::total_deoptimization_count() {
   return _deoptimization_hist[Reason_none][0][0];
 }
 jint Deoptimization::deoptimization_count(DeoptReason reason) {
   assert(reason >= 0 && reason < Reason_LIMIT, "oob");
   return _deoptimization_hist[reason][0][0];
 }
 void Deoptimization::print_statistics() {
   juint total = total_deoptimization_count();
   juint account = total;
   if (total != 0) {
     ttyLocker ttyl;
     if (xtty != NULL)  xtty->head("statistics type='deoptimization'");
     tty->print_cr("Deoptimization traps recorded:");
     #define PRINT_STAT_LINE(name, r) \
       tty->print_cr("  %4d (%4.1f%%) %s", (int)(r), ((r) * 100.0) / total, name);
     PRINT_STAT_LINE("total", total);
     // For each non-zero entry in the histogram, print the reason,
     // the action, and (if specifically known) the type of bytecode.
     for (int reason = 0; reason < Reason_LIMIT; reason++) {
       for (int action = 0; action < Action_LIMIT; action++) {
         juint* cases = _deoptimization_hist[reason][1+action];
         for (int bc_case = 0; bc_case < BC_CASE_LIMIT; bc_case++) {
           juint counter = cases[bc_case];
           if (counter != 0) {
             char name[1*K];
             Bytecodes::Code bc = (Bytecodes::Code)(counter & LSB_MASK);
             if (bc_case == BC_CASE_LIMIT && (int)bc == 0)
               bc = Bytecodes::_illegal;
             sprintf(name, "%s/%s/%s",
                     trap_reason_name(reason),
                     trap_action_name(action),
                     Bytecodes::is_defined(bc)? Bytecodes::name(bc): "other");
             juint r = counter >> LSB_BITS;
             tty->print_cr("  %40s: " UINT32_FORMAT " (%.1f%%)", name, r, (r * 100.0) / total);
             account -= r;
           }
         }
       }
     }
     if (account != 0) {
       PRINT_STAT_LINE("unaccounted", account);
     }
     #undef PRINT_STAT_LINE
     if (xtty != NULL)  xtty->tail("statistics");
   }
 }
 #else // COMPILER2
 // Stubs for C1 only system.
 bool Deoptimization::trap_state_is_recompiled(int trap_state) {
   return false;
 }
 const char* Deoptimization::trap_reason_name(int reason) {
   return "unknown";
 }
 void Deoptimization::print_statistics() {
   // no output
 }
 void
 Deoptimization::update_method_data_from_interpreter(methodDataHandle trap_mdo, int trap_bci, int reason) {
   // no udpate
 }
 int Deoptimization::trap_state_has_reason(int trap_state, int reason) {
   return 0;
 }
 void Deoptimization::gather_statistics(DeoptReason reason, DeoptAction action,
                                        Bytecodes::Code bc) {
   // no update
 }
 const char* Deoptimization::format_trap_state(char* buf, size_t buflen,
                                               int trap_state) {
   jio_snprintf(buf, buflen, "#%d", trap_state);
   return buf;
 }
 #endif // COMPILER2

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/runtime/deoptimization.cpp@52fed2ec0afb (annotated)

src/share/vm/runtime/deoptimization.cpp