jdk8-mips64-public/hotspot: src/share/vm/opto/matcher.cpp@97125851f396 (annotated)

src/share/vm/opto/matcher.cpp@97125851f396 (annotated)

src/share/vm/opto/matcher.cpp

Tue, 05 Jan 2010 13:05:58 +0100

author: twisti
date: Tue, 05 Jan 2010 13:05:58 +0100
changeset 1572: 97125851f396
parent 1496: 09572fede9d1
child 1638: 844a9d73ec22
permissions: -rw-r--r--

6829187: compiler optimizations required for JSR 292
Summary: C2 implementation for invokedynamic support.
Reviewed-by: kvn, never

 /*
  * Copyright 1997-2009 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/_matcher.cpp.incl"
 OptoReg::Name OptoReg::c_frame_pointer;
 const int Matcher::base2reg[Type::lastype] = {
   Node::NotAMachineReg,0,0, Op_RegI, Op_RegL, 0, Op_RegN,
   Node::NotAMachineReg, Node::NotAMachineReg, /* tuple, array */
   Op_RegP, Op_RegP, Op_RegP, Op_RegP, Op_RegP, Op_RegP, /* the pointers */
 , 0/*abio*/,
   Op_RegP /* Return address */, 0, /* the memories */
   Op_RegF, Op_RegF, Op_RegF, Op_RegD, Op_RegD, Op_RegD,
 /*bottom*/
 };
 const RegMask *Matcher::idealreg2regmask[_last_machine_leaf];
 RegMask Matcher::mreg2regmask[_last_Mach_Reg];
 RegMask Matcher::STACK_ONLY_mask;
 RegMask Matcher::c_frame_ptr_mask;
 const uint Matcher::_begin_rematerialize = _BEGIN_REMATERIALIZE;
 const uint Matcher::_end_rematerialize   = _END_REMATERIALIZE;
 //---------------------------Matcher-------------------------------------------
 Matcher::Matcher( Node_List &proj_list ) :
   PhaseTransform( Phase::Ins_Select ),
 #ifdef ASSERT
   _old2new_map(C->comp_arena()),
   _new2old_map(C->comp_arena()),
 #endif
   _shared_nodes(C->comp_arena()),
   _reduceOp(reduceOp), _leftOp(leftOp), _rightOp(rightOp),
   _swallowed(swallowed),
   _begin_inst_chain_rule(_BEGIN_INST_CHAIN_RULE),
   _end_inst_chain_rule(_END_INST_CHAIN_RULE),
   _must_clone(must_clone), _proj_list(proj_list),
   _register_save_policy(register_save_policy),
   _c_reg_save_policy(c_reg_save_policy),
   _register_save_type(register_save_type),
   _ruleName(ruleName),
   _allocation_started(false),
   _states_arena(Chunk::medium_size),
   _visited(&_states_arena),
   _shared(&_states_arena),
   _dontcare(&_states_arena) {
   C->set_matcher(this);
   idealreg2spillmask  [Op_RegI] = NULL;
   idealreg2spillmask  [Op_RegN] = NULL;
   idealreg2spillmask  [Op_RegL] = NULL;
   idealreg2spillmask  [Op_RegF] = NULL;
   idealreg2spillmask  [Op_RegD] = NULL;
   idealreg2spillmask  [Op_RegP] = NULL;
   idealreg2debugmask  [Op_RegI] = NULL;
   idealreg2debugmask  [Op_RegN] = NULL;
   idealreg2debugmask  [Op_RegL] = NULL;
   idealreg2debugmask  [Op_RegF] = NULL;
   idealreg2debugmask  [Op_RegD] = NULL;
   idealreg2debugmask  [Op_RegP] = NULL;
   idealreg2mhdebugmask[Op_RegI] = NULL;
   idealreg2mhdebugmask[Op_RegN] = NULL;
   idealreg2mhdebugmask[Op_RegL] = NULL;
   idealreg2mhdebugmask[Op_RegF] = NULL;
   idealreg2mhdebugmask[Op_RegD] = NULL;
   idealreg2mhdebugmask[Op_RegP] = NULL;
   debug_only(_mem_node = NULL;)   // Ideal memory node consumed by mach node
 }
 //------------------------------warp_incoming_stk_arg------------------------
 // This warps a VMReg into an OptoReg::Name
 OptoReg::Name Matcher::warp_incoming_stk_arg( VMReg reg ) {
   OptoReg::Name warped;
   if( reg->is_stack() ) {  // Stack slot argument?
     warped = OptoReg::add(_old_SP, reg->reg2stack() );
     warped = OptoReg::add(warped, C->out_preserve_stack_slots());
     if( warped >= _in_arg_limit )
       _in_arg_limit = OptoReg::add(warped, 1); // Bump max stack slot seen
     if (!RegMask::can_represent(warped)) {
       // the compiler cannot represent this method's calling sequence
       C->record_method_not_compilable_all_tiers("unsupported incoming calling sequence");
       return OptoReg::Bad;
     }
     return warped;
   }
   return OptoReg::as_OptoReg(reg);
 }
 //---------------------------compute_old_SP------------------------------------
 OptoReg::Name Compile::compute_old_SP() {
   int fixed    = fixed_slots();
   int preserve = in_preserve_stack_slots();
   return OptoReg::stack2reg(round_to(fixed + preserve, Matcher::stack_alignment_in_slots()));
 }
 #ifdef ASSERT
 void Matcher::verify_new_nodes_only(Node* xroot) {
   // Make sure that the new graph only references new nodes
   ResourceMark rm;
   Unique_Node_List worklist;
   VectorSet visited(Thread::current()->resource_area());
   worklist.push(xroot);
   while (worklist.size() > 0) {
     Node* n = worklist.pop();
     visited <<= n->_idx;
     assert(C->node_arena()->contains(n), "dead node");
     for (uint j = 0; j < n->req(); j++) {
       Node* in = n->in(j);
       if (in != NULL) {
         assert(C->node_arena()->contains(in), "dead node");
         if (!visited.test(in->_idx)) {
           worklist.push(in);
         }
       }
     }
   }
 }
 #endif
 //---------------------------match---------------------------------------------
 void Matcher::match( ) {
   if( MaxLabelRootDepth < 100 ) { // Too small?
     assert(false, "invalid MaxLabelRootDepth, increase it to 100 minimum");
     MaxLabelRootDepth = 100;
   }
   // One-time initialization of some register masks.
   init_spill_mask( C->root()->in(1) );
   _return_addr_mask = return_addr();
 #ifdef _LP64
   // Pointers take 2 slots in 64-bit land
   _return_addr_mask.Insert(OptoReg::add(return_addr(),1));
 #endif
   // Map a Java-signature return type into return register-value
   // machine registers for 0, 1 and 2 returned values.
   const TypeTuple *range = C->tf()->range();
   if( range->cnt() > TypeFunc::Parms ) { // If not a void function
     // Get ideal-register return type
     int ireg = base2reg[range->field_at(TypeFunc::Parms)->base()];
     // Get machine return register
     uint sop = C->start()->Opcode();
     OptoRegPair regs = return_value(ireg, false);
     // And mask for same
     _return_value_mask = RegMask(regs.first());
     if( OptoReg::is_valid(regs.second()) )
       _return_value_mask.Insert(regs.second());
   }
   // ---------------
   // Frame Layout
   // Need the method signature to determine the incoming argument types,
   // because the types determine which registers the incoming arguments are
   // in, and this affects the matched code.
   const TypeTuple *domain = C->tf()->domain();
   uint             argcnt = domain->cnt() - TypeFunc::Parms;
   BasicType *sig_bt        = NEW_RESOURCE_ARRAY( BasicType, argcnt );
   VMRegPair *vm_parm_regs  = NEW_RESOURCE_ARRAY( VMRegPair, argcnt );
   _parm_regs               = NEW_RESOURCE_ARRAY( OptoRegPair, argcnt );
   _calling_convention_mask = NEW_RESOURCE_ARRAY( RegMask, argcnt );
   uint i;
   for( i = 0; i<argcnt; i++ ) {
     sig_bt[i] = domain->field_at(i+TypeFunc::Parms)->basic_type();
   }
   // Pass array of ideal registers and length to USER code (from the AD file)
   // that will convert this to an array of register numbers.
   const StartNode *start = C->start();
   start->calling_convention( sig_bt, vm_parm_regs, argcnt );
 #ifdef ASSERT
   // Sanity check users' calling convention.  Real handy while trying to
   // get the initial port correct.
   { for (uint i = 0; i<argcnt; i++) {
       if( !vm_parm_regs[i].first()->is_valid() && !vm_parm_regs[i].second()->is_valid() ) {
         assert(domain->field_at(i+TypeFunc::Parms)==Type::HALF, "only allowed on halve" );
         _parm_regs[i].set_bad();
         continue;
       }
       VMReg parm_reg = vm_parm_regs[i].first();
       assert(parm_reg->is_valid(), "invalid arg?");
       if (parm_reg->is_reg()) {
         OptoReg::Name opto_parm_reg = OptoReg::as_OptoReg(parm_reg);
         assert(can_be_java_arg(opto_parm_reg) ||
                C->stub_function() == CAST_FROM_FN_PTR(address, OptoRuntime::rethrow_C) ||
                opto_parm_reg == inline_cache_reg(),
                "parameters in register must be preserved by runtime stubs");
       }
       for (uint j = 0; j < i; j++) {
         assert(parm_reg != vm_parm_regs[j].first(),
                "calling conv. must produce distinct regs");
       }
     }
   }
 #endif
   // Do some initial frame layout.
   // Compute the old incoming SP (may be called FP) as
   //   OptoReg::stack0() + locks + in_preserve_stack_slots + pad2.
   _old_SP = C->compute_old_SP();
   assert( is_even(_old_SP), "must be even" );
   // Compute highest incoming stack argument as
   //   _old_SP + out_preserve_stack_slots + incoming argument size.
   _in_arg_limit = OptoReg::add(_old_SP, C->out_preserve_stack_slots());
   assert( is_even(_in_arg_limit), "out_preserve must be even" );
   for( i = 0; i < argcnt; i++ ) {
     // Permit args to have no register
     _calling_convention_mask[i].Clear();
     if( !vm_parm_regs[i].first()->is_valid() && !vm_parm_regs[i].second()->is_valid() ) {
       continue;
     }
     // calling_convention returns stack arguments as a count of
     // slots beyond OptoReg::stack0()/VMRegImpl::stack0.  We need to convert this to
     // the allocators point of view, taking into account all the
     // preserve area, locks & pad2.
     OptoReg::Name reg1 = warp_incoming_stk_arg(vm_parm_regs[i].first());
     if( OptoReg::is_valid(reg1))
       _calling_convention_mask[i].Insert(reg1);
     OptoReg::Name reg2 = warp_incoming_stk_arg(vm_parm_regs[i].second());
     if( OptoReg::is_valid(reg2))
       _calling_convention_mask[i].Insert(reg2);
     // Saved biased stack-slot register number
     _parm_regs[i].set_pair(reg2, reg1);
   }
   // Finally, make sure the incoming arguments take up an even number of
   // words, in case the arguments or locals need to contain doubleword stack
   // slots.  The rest of the system assumes that stack slot pairs (in
   // particular, in the spill area) which look aligned will in fact be
   // aligned relative to the stack pointer in the target machine.  Double
   // stack slots will always be allocated aligned.
   _new_SP = OptoReg::Name(round_to(_in_arg_limit, RegMask::SlotsPerLong));
   // Compute highest outgoing stack argument as
   //   _new_SP + out_preserve_stack_slots + max(outgoing argument size).
   _out_arg_limit = OptoReg::add(_new_SP, C->out_preserve_stack_slots());
   assert( is_even(_out_arg_limit), "out_preserve must be even" );
   if (!RegMask::can_represent(OptoReg::add(_out_arg_limit,-1))) {
     // the compiler cannot represent this method's calling sequence
     C->record_method_not_compilable("must be able to represent all call arguments in reg mask");
   }
   if (C->failing())  return;  // bailed out on incoming arg failure
   // ---------------
   // Collect roots of matcher trees.  Every node for which
   // _shared[_idx] is cleared is guaranteed to not be shared, and thus
   // can be a valid interior of some tree.
   find_shared( C->root() );
   find_shared( C->top() );
   C->print_method("Before Matching");
   // Create new ideal node ConP #NULL even if it does exist in old space
   // to avoid false sharing if the corresponding mach node is not used.
   // The corresponding mach node is only used in rare cases for derived
   // pointers.
   Node* new_ideal_null = ConNode::make(C, TypePtr::NULL_PTR);
   // Swap out to old-space; emptying new-space
   Arena *old = C->node_arena()->move_contents(C->old_arena());
   // Save debug and profile information for nodes in old space:
   _old_node_note_array = C->node_note_array();
   if (_old_node_note_array != NULL) {
     C->set_node_note_array(new(C->comp_arena()) GrowableArray<Node_Notes*>
                            (C->comp_arena(), _old_node_note_array->length(),
 , NULL));
   }
   // Pre-size the new_node table to avoid the need for range checks.
   grow_new_node_array(C->unique());
   // Reset node counter so MachNodes start with _idx at 0
   int nodes = C->unique(); // save value
   C->set_unique(0);
   // Recursively match trees from old space into new space.
   // Correct leaves of new-space Nodes; they point to old-space.
   _visited.Clear();             // Clear visit bits for xform call
   C->set_cached_top_node(xform( C->top(), nodes ));
   if (!C->failing()) {
     Node* xroot =        xform( C->root(), 1 );
     if (xroot == NULL) {
       Matcher::soft_match_failure();  // recursive matching process failed
       C->record_method_not_compilable("instruction match failed");
     } else {
       // During matching shared constants were attached to C->root()
       // because xroot wasn't available yet, so transfer the uses to
       // the xroot.
       for( DUIterator_Fast jmax, j = C->root()->fast_outs(jmax); j < jmax; j++ ) {
         Node* n = C->root()->fast_out(j);
         if (C->node_arena()->contains(n)) {
           assert(n->in(0) == C->root(), "should be control user");
           n->set_req(0, xroot);
           --j;
           --jmax;
         }
       }
       // Generate new mach node for ConP #NULL
       assert(new_ideal_null != NULL, "sanity");
       _mach_null = match_tree(new_ideal_null);
       // Don't set control, it will confuse GCM since there are no uses.
       // The control will be set when this node is used first time
       // in find_base_for_derived().
       assert(_mach_null != NULL, "");
       C->set_root(xroot->is_Root() ? xroot->as_Root() : NULL);
 #ifdef ASSERT
       verify_new_nodes_only(xroot);
 #endif
     }
   }
   if (C->top() == NULL || C->root() == NULL) {
     C->record_method_not_compilable("graph lost"); // %%% cannot happen?
   }
   if (C->failing()) {
     // delete old;
     old->destruct_contents();
     return;
   }
   assert( C->top(), "" );
   assert( C->root(), "" );
   validate_null_checks();
   // Now smoke old-space
   NOT_DEBUG( old->destruct_contents() );
   // ------------------------
   // Set up save-on-entry registers
   Fixup_Save_On_Entry( );
 }
 //------------------------------Fixup_Save_On_Entry----------------------------
 // The stated purpose of this routine is to take care of save-on-entry
 // registers.  However, the overall goal of the Match phase is to convert into
 // machine-specific instructions which have RegMasks to guide allocation.
 // So what this procedure really does is put a valid RegMask on each input
 // to the machine-specific variations of all Return, TailCall and Halt
 // instructions.  It also adds edgs to define the save-on-entry values (and of
 // course gives them a mask).
 static RegMask *init_input_masks( uint size, RegMask &ret_adr, RegMask &fp ) {
   RegMask *rms = NEW_RESOURCE_ARRAY( RegMask, size );
   // Do all the pre-defined register masks
   rms[TypeFunc::Control  ] = RegMask::Empty;
   rms[TypeFunc::I_O      ] = RegMask::Empty;
   rms[TypeFunc::Memory   ] = RegMask::Empty;
   rms[TypeFunc::ReturnAdr] = ret_adr;
   rms[TypeFunc::FramePtr ] = fp;
   return rms;
 }
 //---------------------------init_first_stack_mask-----------------------------
 // Create the initial stack mask used by values spilling to the stack.
 // Disallow any debug info in outgoing argument areas by setting the
 // initial mask accordingly.
 void Matcher::init_first_stack_mask() {
   // Allocate storage for spill masks as masks for the appropriate load type.
   RegMask *rms = (RegMask*)C->comp_arena()->Amalloc_D(sizeof(RegMask) * 3*6);
   idealreg2spillmask  [Op_RegN] = &rms[0];
   idealreg2spillmask  [Op_RegI] = &rms[1];
   idealreg2spillmask  [Op_RegL] = &rms[2];
   idealreg2spillmask  [Op_RegF] = &rms[3];
   idealreg2spillmask  [Op_RegD] = &rms[4];
   idealreg2spillmask  [Op_RegP] = &rms[5];
   idealreg2debugmask  [Op_RegN] = &rms[6];
   idealreg2debugmask  [Op_RegI] = &rms[7];
   idealreg2debugmask  [Op_RegL] = &rms[8];
   idealreg2debugmask  [Op_RegF] = &rms[9];
   idealreg2debugmask  [Op_RegD] = &rms[10];
   idealreg2debugmask  [Op_RegP] = &rms[11];
   idealreg2mhdebugmask[Op_RegN] = &rms[12];
   idealreg2mhdebugmask[Op_RegI] = &rms[13];
   idealreg2mhdebugmask[Op_RegL] = &rms[14];
   idealreg2mhdebugmask[Op_RegF] = &rms[15];
   idealreg2mhdebugmask[Op_RegD] = &rms[16];
   idealreg2mhdebugmask[Op_RegP] = &rms[17];
   OptoReg::Name i;
   // At first, start with the empty mask
   C->FIRST_STACK_mask().Clear();
   // Add in the incoming argument area
   OptoReg::Name init = OptoReg::add(_old_SP, C->out_preserve_stack_slots());
   for (i = init; i < _in_arg_limit; i = OptoReg::add(i,1))
     C->FIRST_STACK_mask().Insert(i);
   // Add in all bits past the outgoing argument area
   guarantee(RegMask::can_represent(OptoReg::add(_out_arg_limit,-1)),
             "must be able to represent all call arguments in reg mask");
   init = _out_arg_limit;
   for (i = init; RegMask::can_represent(i); i = OptoReg::add(i,1))
     C->FIRST_STACK_mask().Insert(i);
   // Finally, set the "infinite stack" bit.
   C->FIRST_STACK_mask().set_AllStack();
   // Make spill masks.  Registers for their class, plus FIRST_STACK_mask.
 #ifdef _LP64
   *idealreg2spillmask[Op_RegN] = *idealreg2regmask[Op_RegN];
    idealreg2spillmask[Op_RegN]->OR(C->FIRST_STACK_mask());
 #endif
   *idealreg2spillmask[Op_RegI] = *idealreg2regmask[Op_RegI];
    idealreg2spillmask[Op_RegI]->OR(C->FIRST_STACK_mask());
   *idealreg2spillmask[Op_RegL] = *idealreg2regmask[Op_RegL];
    idealreg2spillmask[Op_RegL]->OR(C->FIRST_STACK_mask());
   *idealreg2spillmask[Op_RegF] = *idealreg2regmask[Op_RegF];
    idealreg2spillmask[Op_RegF]->OR(C->FIRST_STACK_mask());
   *idealreg2spillmask[Op_RegD] = *idealreg2regmask[Op_RegD];
    idealreg2spillmask[Op_RegD]->OR(C->FIRST_STACK_mask());
   *idealreg2spillmask[Op_RegP] = *idealreg2regmask[Op_RegP];
    idealreg2spillmask[Op_RegP]->OR(C->FIRST_STACK_mask());
   // Make up debug masks.  Any spill slot plus callee-save registers.
   // Caller-save registers are assumed to be trashable by the various
   // inline-cache fixup routines.
   *idealreg2debugmask  [Op_RegN]= *idealreg2spillmask[Op_RegN];
   *idealreg2debugmask  [Op_RegI]= *idealreg2spillmask[Op_RegI];
   *idealreg2debugmask  [Op_RegL]= *idealreg2spillmask[Op_RegL];
   *idealreg2debugmask  [Op_RegF]= *idealreg2spillmask[Op_RegF];
   *idealreg2debugmask  [Op_RegD]= *idealreg2spillmask[Op_RegD];
   *idealreg2debugmask  [Op_RegP]= *idealreg2spillmask[Op_RegP];
   *idealreg2mhdebugmask[Op_RegN]= *idealreg2spillmask[Op_RegN];
   *idealreg2mhdebugmask[Op_RegI]= *idealreg2spillmask[Op_RegI];
   *idealreg2mhdebugmask[Op_RegL]= *idealreg2spillmask[Op_RegL];
   *idealreg2mhdebugmask[Op_RegF]= *idealreg2spillmask[Op_RegF];
   *idealreg2mhdebugmask[Op_RegD]= *idealreg2spillmask[Op_RegD];
   *idealreg2mhdebugmask[Op_RegP]= *idealreg2spillmask[Op_RegP];
   // Prevent stub compilations from attempting to reference
   // callee-saved registers from debug info
   bool exclude_soe = !Compile::current()->is_method_compilation();
   for( i=OptoReg::Name(0); i<OptoReg::Name(_last_Mach_Reg); i = OptoReg::add(i,1) ) {
     // registers the caller has to save do not work
     if( _register_save_policy[i] == 'C' ||
         _register_save_policy[i] == 'A' ||
         (_register_save_policy[i] == 'E' && exclude_soe) ) {
       idealreg2debugmask  [Op_RegN]->Remove(i);
       idealreg2debugmask  [Op_RegI]->Remove(i); // Exclude save-on-call
       idealreg2debugmask  [Op_RegL]->Remove(i); // registers from debug
       idealreg2debugmask  [Op_RegF]->Remove(i); // masks
       idealreg2debugmask  [Op_RegD]->Remove(i);
       idealreg2debugmask  [Op_RegP]->Remove(i);
       idealreg2mhdebugmask[Op_RegN]->Remove(i);
       idealreg2mhdebugmask[Op_RegI]->Remove(i);
       idealreg2mhdebugmask[Op_RegL]->Remove(i);
       idealreg2mhdebugmask[Op_RegF]->Remove(i);
       idealreg2mhdebugmask[Op_RegD]->Remove(i);
       idealreg2mhdebugmask[Op_RegP]->Remove(i);
     }
   }
   // Subtract the register we use to save the SP for MethodHandle
   // invokes to from the debug mask.
   const RegMask save_mask = method_handle_invoke_SP_save_mask();
   idealreg2mhdebugmask[Op_RegN]->SUBTRACT(save_mask);
   idealreg2mhdebugmask[Op_RegI]->SUBTRACT(save_mask);
   idealreg2mhdebugmask[Op_RegL]->SUBTRACT(save_mask);
   idealreg2mhdebugmask[Op_RegF]->SUBTRACT(save_mask);
   idealreg2mhdebugmask[Op_RegD]->SUBTRACT(save_mask);
   idealreg2mhdebugmask[Op_RegP]->SUBTRACT(save_mask);
 }
 //---------------------------is_save_on_entry----------------------------------
 bool Matcher::is_save_on_entry( int reg ) {
   return
     _register_save_policy[reg] == 'E' ||
     _register_save_policy[reg] == 'A' || // Save-on-entry register?
     // Also save argument registers in the trampolining stubs
     (C->save_argument_registers() && is_spillable_arg(reg));
 }
 //---------------------------Fixup_Save_On_Entry-------------------------------
 void Matcher::Fixup_Save_On_Entry( ) {
   init_first_stack_mask();
   Node *root = C->root();       // Short name for root
   // Count number of save-on-entry registers.
   uint soe_cnt = number_of_saved_registers();
   uint i;
   // Find the procedure Start Node
   StartNode *start = C->start();
   assert( start, "Expect a start node" );
   // Save argument registers in the trampolining stubs
   if( C->save_argument_registers() )
     for( i = 0; i < _last_Mach_Reg; i++ )
       if( is_spillable_arg(i) )
         soe_cnt++;
   // Input RegMask array shared by all Returns.
   // The type for doubles and longs has a count of 2, but
   // there is only 1 returned value
   uint ret_edge_cnt = TypeFunc::Parms + ((C->tf()->range()->cnt() == TypeFunc::Parms) ? 0 : 1);
   RegMask *ret_rms  = init_input_masks( ret_edge_cnt + soe_cnt, _return_addr_mask, c_frame_ptr_mask );
   // Returns have 0 or 1 returned values depending on call signature.
   // Return register is specified by return_value in the AD file.
   if (ret_edge_cnt > TypeFunc::Parms)
     ret_rms[TypeFunc::Parms+0] = _return_value_mask;
   // Input RegMask array shared by all Rethrows.
   uint reth_edge_cnt = TypeFunc::Parms+1;
   RegMask *reth_rms  = init_input_masks( reth_edge_cnt + soe_cnt, _return_addr_mask, c_frame_ptr_mask );
   // Rethrow takes exception oop only, but in the argument 0 slot.
   reth_rms[TypeFunc::Parms] = mreg2regmask[find_receiver(false)];
 #ifdef _LP64
   // Need two slots for ptrs in 64-bit land
   reth_rms[TypeFunc::Parms].Insert(OptoReg::add(OptoReg::Name(find_receiver(false)),1));
 #endif
   // Input RegMask array shared by all TailCalls
   uint tail_call_edge_cnt = TypeFunc::Parms+2;
   RegMask *tail_call_rms = init_input_masks( tail_call_edge_cnt + soe_cnt, _return_addr_mask, c_frame_ptr_mask );
   // Input RegMask array shared by all TailJumps
   uint tail_jump_edge_cnt = TypeFunc::Parms+2;
   RegMask *tail_jump_rms = init_input_masks( tail_jump_edge_cnt + soe_cnt, _return_addr_mask, c_frame_ptr_mask );
   // TailCalls have 2 returned values (target & moop), whose masks come
   // from the usual MachNode/MachOper mechanism.  Find a sample
   // TailCall to extract these masks and put the correct masks into
   // the tail_call_rms array.
   for( i=1; i < root->req(); i++ ) {
     MachReturnNode *m = root->in(i)->as_MachReturn();
     if( m->ideal_Opcode() == Op_TailCall ) {
       tail_call_rms[TypeFunc::Parms+0] = m->MachNode::in_RegMask(TypeFunc::Parms+0);
       tail_call_rms[TypeFunc::Parms+1] = m->MachNode::in_RegMask(TypeFunc::Parms+1);
       break;
     }
   }
   // TailJumps have 2 returned values (target & ex_oop), whose masks come
   // from the usual MachNode/MachOper mechanism.  Find a sample
   // TailJump to extract these masks and put the correct masks into
   // the tail_jump_rms array.
   for( i=1; i < root->req(); i++ ) {
     MachReturnNode *m = root->in(i)->as_MachReturn();
     if( m->ideal_Opcode() == Op_TailJump ) {
       tail_jump_rms[TypeFunc::Parms+0] = m->MachNode::in_RegMask(TypeFunc::Parms+0);
       tail_jump_rms[TypeFunc::Parms+1] = m->MachNode::in_RegMask(TypeFunc::Parms+1);
       break;
     }
   }
   // Input RegMask array shared by all Halts
   uint halt_edge_cnt = TypeFunc::Parms;
   RegMask *halt_rms = init_input_masks( halt_edge_cnt + soe_cnt, _return_addr_mask, c_frame_ptr_mask );
   // Capture the return input masks into each exit flavor
   for( i=1; i < root->req(); i++ ) {
     MachReturnNode *exit = root->in(i)->as_MachReturn();
     switch( exit->ideal_Opcode() ) {
       case Op_Return   : exit->_in_rms = ret_rms;  break;
       case Op_Rethrow  : exit->_in_rms = reth_rms; break;
       case Op_TailCall : exit->_in_rms = tail_call_rms; break;
       case Op_TailJump : exit->_in_rms = tail_jump_rms; break;
       case Op_Halt     : exit->_in_rms = halt_rms; break;
       default          : ShouldNotReachHere();
     }
   }
   // Next unused projection number from Start.
   int proj_cnt = C->tf()->domain()->cnt();
   // Do all the save-on-entry registers.  Make projections from Start for
   // them, and give them a use at the exit points.  To the allocator, they
   // look like incoming register arguments.
   for( i = 0; i < _last_Mach_Reg; i++ ) {
     if( is_save_on_entry(i) ) {
       // Add the save-on-entry to the mask array
       ret_rms      [      ret_edge_cnt] = mreg2regmask[i];
       reth_rms     [     reth_edge_cnt] = mreg2regmask[i];
       tail_call_rms[tail_call_edge_cnt] = mreg2regmask[i];
       tail_jump_rms[tail_jump_edge_cnt] = mreg2regmask[i];
       // Halts need the SOE registers, but only in the stack as debug info.
       // A just-prior uncommon-trap or deoptimization will use the SOE regs.
       halt_rms     [     halt_edge_cnt] = *idealreg2spillmask[_register_save_type[i]];
       Node *mproj;
       // Is this a RegF low half of a RegD?  Double up 2 adjacent RegF's
       // into a single RegD.
       if( (i&1) == 0 &&
           _register_save_type[i  ] == Op_RegF &&
           _register_save_type[i+1] == Op_RegF &&
           is_save_on_entry(i+1) ) {
         // Add other bit for double
         ret_rms      [      ret_edge_cnt].Insert(OptoReg::Name(i+1));
         reth_rms     [     reth_edge_cnt].Insert(OptoReg::Name(i+1));
         tail_call_rms[tail_call_edge_cnt].Insert(OptoReg::Name(i+1));
         tail_jump_rms[tail_jump_edge_cnt].Insert(OptoReg::Name(i+1));
         halt_rms     [     halt_edge_cnt].Insert(OptoReg::Name(i+1));
         mproj = new (C, 1) MachProjNode( start, proj_cnt, ret_rms[ret_edge_cnt], Op_RegD );
         proj_cnt += 2;          // Skip 2 for doubles
       }
       else if( (i&1) == 1 &&    // Else check for high half of double
                _register_save_type[i-1] == Op_RegF &&
                _register_save_type[i  ] == Op_RegF &&
                is_save_on_entry(i-1) ) {
         ret_rms      [      ret_edge_cnt] = RegMask::Empty;
         reth_rms     [     reth_edge_cnt] = RegMask::Empty;
         tail_call_rms[tail_call_edge_cnt] = RegMask::Empty;
         tail_jump_rms[tail_jump_edge_cnt] = RegMask::Empty;
         halt_rms     [     halt_edge_cnt] = RegMask::Empty;
         mproj = C->top();
       }
       // Is this a RegI low half of a RegL?  Double up 2 adjacent RegI's
       // into a single RegL.
       else if( (i&1) == 0 &&
           _register_save_type[i  ] == Op_RegI &&
           _register_save_type[i+1] == Op_RegI &&
         is_save_on_entry(i+1) ) {
         // Add other bit for long
         ret_rms      [      ret_edge_cnt].Insert(OptoReg::Name(i+1));
         reth_rms     [     reth_edge_cnt].Insert(OptoReg::Name(i+1));
         tail_call_rms[tail_call_edge_cnt].Insert(OptoReg::Name(i+1));
         tail_jump_rms[tail_jump_edge_cnt].Insert(OptoReg::Name(i+1));
         halt_rms     [     halt_edge_cnt].Insert(OptoReg::Name(i+1));
         mproj = new (C, 1) MachProjNode( start, proj_cnt, ret_rms[ret_edge_cnt], Op_RegL );
         proj_cnt += 2;          // Skip 2 for longs
       }
       else if( (i&1) == 1 &&    // Else check for high half of long
                _register_save_type[i-1] == Op_RegI &&
                _register_save_type[i  ] == Op_RegI &&
                is_save_on_entry(i-1) ) {
         ret_rms      [      ret_edge_cnt] = RegMask::Empty;
         reth_rms     [     reth_edge_cnt] = RegMask::Empty;
         tail_call_rms[tail_call_edge_cnt] = RegMask::Empty;
         tail_jump_rms[tail_jump_edge_cnt] = RegMask::Empty;
         halt_rms     [     halt_edge_cnt] = RegMask::Empty;
         mproj = C->top();
       } else {
         // Make a projection for it off the Start
         mproj = new (C, 1) MachProjNode( start, proj_cnt++, ret_rms[ret_edge_cnt], _register_save_type[i] );
       }
       ret_edge_cnt ++;
       reth_edge_cnt ++;
       tail_call_edge_cnt ++;
       tail_jump_edge_cnt ++;
       halt_edge_cnt ++;
       // Add a use of the SOE register to all exit paths
       for( uint j=1; j < root->req(); j++ )
         root->in(j)->add_req(mproj);
     } // End of if a save-on-entry register
   } // End of for all machine registers
 }
 //------------------------------init_spill_mask--------------------------------
 void Matcher::init_spill_mask( Node *ret ) {
   if( idealreg2regmask[Op_RegI] ) return; // One time only init
   OptoReg::c_frame_pointer = c_frame_pointer();
   c_frame_ptr_mask = c_frame_pointer();
 #ifdef _LP64
   // pointers are twice as big
   c_frame_ptr_mask.Insert(OptoReg::add(c_frame_pointer(),1));
 #endif
   // Start at OptoReg::stack0()
   STACK_ONLY_mask.Clear();
   OptoReg::Name init = OptoReg::stack2reg(0);
   // STACK_ONLY_mask is all stack bits
   OptoReg::Name i;
   for (i = init; RegMask::can_represent(i); i = OptoReg::add(i,1))
     STACK_ONLY_mask.Insert(i);
   // Also set the "infinite stack" bit.
   STACK_ONLY_mask.set_AllStack();
   // Copy the register names over into the shared world
   for( i=OptoReg::Name(0); i<OptoReg::Name(_last_Mach_Reg); i = OptoReg::add(i,1) ) {
     // SharedInfo::regName[i] = regName[i];
     // Handy RegMasks per machine register
     mreg2regmask[i].Insert(i);
   }
   // Grab the Frame Pointer
   Node *fp  = ret->in(TypeFunc::FramePtr);
   Node *mem = ret->in(TypeFunc::Memory);
   const TypePtr* atp = TypePtr::BOTTOM;
   // Share frame pointer while making spill ops
   set_shared(fp);
   // Compute generic short-offset Loads
 #ifdef _LP64
   MachNode *spillCP = match_tree(new (C, 3) LoadNNode(NULL,mem,fp,atp,TypeInstPtr::BOTTOM));
 #endif
   MachNode *spillI  = match_tree(new (C, 3) LoadINode(NULL,mem,fp,atp));
   MachNode *spillL  = match_tree(new (C, 3) LoadLNode(NULL,mem,fp,atp));
   MachNode *spillF  = match_tree(new (C, 3) LoadFNode(NULL,mem,fp,atp));
   MachNode *spillD  = match_tree(new (C, 3) LoadDNode(NULL,mem,fp,atp));
   MachNode *spillP  = match_tree(new (C, 3) LoadPNode(NULL,mem,fp,atp,TypeInstPtr::BOTTOM));
   assert(spillI != NULL && spillL != NULL && spillF != NULL &&
          spillD != NULL && spillP != NULL, "");
   // Get the ADLC notion of the right regmask, for each basic type.
 #ifdef _LP64
   idealreg2regmask[Op_RegN] = &spillCP->out_RegMask();
 #endif
   idealreg2regmask[Op_RegI] = &spillI->out_RegMask();
   idealreg2regmask[Op_RegL] = &spillL->out_RegMask();
   idealreg2regmask[Op_RegF] = &spillF->out_RegMask();
   idealreg2regmask[Op_RegD] = &spillD->out_RegMask();
   idealreg2regmask[Op_RegP] = &spillP->out_RegMask();
 }
 #ifdef ASSERT
 static void match_alias_type(Compile* C, Node* n, Node* m) {
   if (!VerifyAliases)  return;  // do not go looking for trouble by default
   const TypePtr* nat = n->adr_type();
   const TypePtr* mat = m->adr_type();
   int nidx = C->get_alias_index(nat);
   int midx = C->get_alias_index(mat);
   // Detune the assert for cases like (AndI 0xFF (LoadB p)).
   if (nidx == Compile::AliasIdxTop && midx >= Compile::AliasIdxRaw) {
     for (uint i = 1; i < n->req(); i++) {
       Node* n1 = n->in(i);
       const TypePtr* n1at = n1->adr_type();
       if (n1at != NULL) {
         nat = n1at;
         nidx = C->get_alias_index(n1at);
       }
     }
   }
   // %%% Kludgery.  Instead, fix ideal adr_type methods for all these cases:
   if (nidx == Compile::AliasIdxTop && midx == Compile::AliasIdxRaw) {
     switch (n->Opcode()) {
     case Op_PrefetchRead:
     case Op_PrefetchWrite:
       nidx = Compile::AliasIdxRaw;
       nat = TypeRawPtr::BOTTOM;
       break;
     }
   }
   if (nidx == Compile::AliasIdxRaw && midx == Compile::AliasIdxTop) {
     switch (n->Opcode()) {
     case Op_ClearArray:
       midx = Compile::AliasIdxRaw;
       mat = TypeRawPtr::BOTTOM;
       break;
     }
   }
   if (nidx == Compile::AliasIdxTop && midx == Compile::AliasIdxBot) {
     switch (n->Opcode()) {
     case Op_Return:
     case Op_Rethrow:
     case Op_Halt:
     case Op_TailCall:
     case Op_TailJump:
       nidx = Compile::AliasIdxBot;
       nat = TypePtr::BOTTOM;
       break;
     }
   }
   if (nidx == Compile::AliasIdxBot && midx == Compile::AliasIdxTop) {
     switch (n->Opcode()) {
     case Op_StrComp:
     case Op_StrEquals:
     case Op_StrIndexOf:
     case Op_AryEq:
     case Op_MemBarVolatile:
     case Op_MemBarCPUOrder: // %%% these ideals should have narrower adr_type?
       nidx = Compile::AliasIdxTop;
       nat = NULL;
       break;
     }
   }
   if (nidx != midx) {
     if (PrintOpto || (PrintMiscellaneous && (WizardMode || Verbose))) {
       tty->print_cr("==== Matcher alias shift %d => %d", nidx, midx);
       n->dump();
       m->dump();
     }
     assert(C->subsume_loads() && C->must_alias(nat, midx),
            "must not lose alias info when matching");
   }
 }
 #endif
 //------------------------------MStack-----------------------------------------
 // State and MStack class used in xform() and find_shared() iterative methods.
 enum Node_State { Pre_Visit,  // node has to be pre-visited
                       Visit,  // visit node
                  Post_Visit,  // post-visit node
              Alt_Post_Visit   // alternative post-visit path
                 };
 class MStack: public Node_Stack {
   public:
     MStack(int size) : Node_Stack(size) { }
     void push(Node *n, Node_State ns) {
       Node_Stack::push(n, (uint)ns);
     }
     void push(Node *n, Node_State ns, Node *parent, int indx) {
       ++_inode_top;
       if ((_inode_top + 1) >= _inode_max) grow();
       _inode_top->node = parent;
       _inode_top->indx = (uint)indx;
       ++_inode_top;
       _inode_top->node = n;
       _inode_top->indx = (uint)ns;
     }
     Node *parent() {
       pop();
       return node();
     }
     Node_State state() const {
       return (Node_State)index();
     }
     void set_state(Node_State ns) {
       set_index((uint)ns);
     }
 };
 //------------------------------xform------------------------------------------
 // Given a Node in old-space, Match him (Label/Reduce) to produce a machine
 // Node in new-space.  Given a new-space Node, recursively walk his children.
 Node *Matcher::transform( Node *n ) { ShouldNotCallThis(); return n; }
 Node *Matcher::xform( Node *n, int max_stack ) {
   // Use one stack to keep both: child's node/state and parent's node/index
   MStack mstack(max_stack * 2 * 2); // C->unique() * 2 * 2
   mstack.push(n, Visit, NULL, -1);  // set NULL as parent to indicate root
   while (mstack.is_nonempty()) {
     n = mstack.node();          // Leave node on stack
     Node_State nstate = mstack.state();
     if (nstate == Visit) {
       mstack.set_state(Post_Visit);
       Node *oldn = n;
       // Old-space or new-space check
       if (!C->node_arena()->contains(n)) {
         // Old space!
         Node* m;
         if (has_new_node(n)) {  // Not yet Label/Reduced
           m = new_node(n);
         } else {
           if (!is_dontcare(n)) { // Matcher can match this guy
             // Calls match special.  They match alone with no children.
             // Their children, the incoming arguments, match normally.
             m = n->is_SafePoint() ? match_sfpt(n->as_SafePoint()):match_tree(n);
             if (C->failing())  return NULL;
             if (m == NULL) { Matcher::soft_match_failure(); return NULL; }
           } else {                  // Nothing the matcher cares about
             if( n->is_Proj() && n->in(0)->is_Multi()) {       // Projections?
               // Convert to machine-dependent projection
               m = n->in(0)->as_Multi()->match( n->as_Proj(), this );
 #ifdef ASSERT
               _new2old_map.map(m->_idx, n);
 #endif
               if (m->in(0) != NULL) // m might be top
                 collect_null_checks(m, n);
             } else {                // Else just a regular 'ol guy
               m = n->clone();       // So just clone into new-space
 #ifdef ASSERT
               _new2old_map.map(m->_idx, n);
 #endif
               // Def-Use edges will be added incrementally as Uses
               // of this node are matched.
               assert(m->outcnt() == 0, "no Uses of this clone yet");
             }
           }
           set_new_node(n, m);       // Map old to new
           if (_old_node_note_array != NULL) {
             Node_Notes* nn = C->locate_node_notes(_old_node_note_array,
                                                   n->_idx);
             C->set_node_notes_at(m->_idx, nn);
           }
           debug_only(match_alias_type(C, n, m));
         }
         n = m;    // n is now a new-space node
         mstack.set_node(n);
       }
       // New space!
       if (_visited.test_set(n->_idx)) continue; // while(mstack.is_nonempty())
       int i;
       // Put precedence edges on stack first (match them last).
       for (i = oldn->req(); (uint)i < oldn->len(); i++) {
         Node *m = oldn->in(i);
         if (m == NULL) break;
         // set -1 to call add_prec() instead of set_req() during Step1
         mstack.push(m, Visit, n, -1);
       }
       // For constant debug info, I'd rather have unmatched constants.
       int cnt = n->req();
       JVMState* jvms = n->jvms();
       int debug_cnt = jvms ? jvms->debug_start() : cnt;
       // Now do only debug info.  Clone constants rather than matching.
       // Constants are represented directly in the debug info without
       // the need for executable machine instructions.
       // Monitor boxes are also represented directly.
       for (i = cnt - 1; i >= debug_cnt; --i) { // For all debug inputs do
         Node *m = n->in(i);          // Get input
         int op = m->Opcode();
         assert((op == Op_BoxLock) == jvms->is_monitor_use(i), "boxes only at monitor sites");
         if( op == Op_ConI || op == Op_ConP || op == Op_ConN ||
             op == Op_ConF || op == Op_ConD || op == Op_ConL
             // || op == Op_BoxLock  // %%%% enable this and remove (+++) in chaitin.cpp
             ) {
           m = m->clone();
 #ifdef ASSERT
           _new2old_map.map(m->_idx, n);
 #endif
           mstack.push(m, Post_Visit, n, i); // Don't need to visit
           mstack.push(m->in(0), Visit, m, 0);
         } else {
           mstack.push(m, Visit, n, i);
         }
       }
       // And now walk his children, and convert his inputs to new-space.
       for( ; i >= 0; --i ) { // For all normal inputs do
         Node *m = n->in(i);  // Get input
         if(m != NULL)
           mstack.push(m, Visit, n, i);
       }
     }
     else if (nstate == Post_Visit) {
       // Set xformed input
       Node *p = mstack.parent();
       if (p != NULL) { // root doesn't have parent
         int i = (int)mstack.index();
         if (i >= 0)
           p->set_req(i, n); // required input
         else if (i == -1)
           p->add_prec(n);   // precedence input
         else
           ShouldNotReachHere();
       }
       mstack.pop(); // remove processed node from stack
     }
     else {
       ShouldNotReachHere();
     }
   } // while (mstack.is_nonempty())
   return n; // Return new-space Node
 }
 //------------------------------warp_outgoing_stk_arg------------------------
 OptoReg::Name Matcher::warp_outgoing_stk_arg( VMReg reg, OptoReg::Name begin_out_arg_area, OptoReg::Name &out_arg_limit_per_call ) {
   // Convert outgoing argument location to a pre-biased stack offset
   if (reg->is_stack()) {
     OptoReg::Name warped = reg->reg2stack();
     // Adjust the stack slot offset to be the register number used
     // by the allocator.
     warped = OptoReg::add(begin_out_arg_area, warped);
     // Keep track of the largest numbered stack slot used for an arg.
     // Largest used slot per call-site indicates the amount of stack
     // that is killed by the call.
     if( warped >= out_arg_limit_per_call )
       out_arg_limit_per_call = OptoReg::add(warped,1);
     if (!RegMask::can_represent(warped)) {
       C->record_method_not_compilable_all_tiers("unsupported calling sequence");
       return OptoReg::Bad;
     }
     return warped;
   }
   return OptoReg::as_OptoReg(reg);
 }
 //------------------------------match_sfpt-------------------------------------
 // Helper function to match call instructions.  Calls match special.
 // They match alone with no children.  Their children, the incoming
 // arguments, match normally.
 MachNode *Matcher::match_sfpt( SafePointNode *sfpt ) {
   MachSafePointNode *msfpt = NULL;
   MachCallNode      *mcall = NULL;
   uint               cnt;
   // Split out case for SafePoint vs Call
   CallNode *call;
   const TypeTuple *domain;
   ciMethod*        method = NULL;
   bool             is_method_handle_invoke = false;  // for special kill effects
   if( sfpt->is_Call() ) {
     call = sfpt->as_Call();
     domain = call->tf()->domain();
     cnt = domain->cnt();
     // Match just the call, nothing else
     MachNode *m = match_tree(call);
     if (C->failing())  return NULL;
     if( m == NULL ) { Matcher::soft_match_failure(); return NULL; }
     // Copy data from the Ideal SafePoint to the machine version
     mcall = m->as_MachCall();
     mcall->set_tf(         call->tf());
     mcall->set_entry_point(call->entry_point());
     mcall->set_cnt(        call->cnt());
     if( mcall->is_MachCallJava() ) {
       MachCallJavaNode *mcall_java  = mcall->as_MachCallJava();
       const CallJavaNode *call_java =  call->as_CallJava();
       method = call_java->method();
       mcall_java->_method = method;
       mcall_java->_bci = call_java->_bci;
       mcall_java->_optimized_virtual = call_java->is_optimized_virtual();
       is_method_handle_invoke = call_java->is_method_handle_invoke();
       mcall_java->_method_handle_invoke = is_method_handle_invoke;
       if( mcall_java->is_MachCallStaticJava() )
         mcall_java->as_MachCallStaticJava()->_name =
          call_java->as_CallStaticJava()->_name;
       if( mcall_java->is_MachCallDynamicJava() )
         mcall_java->as_MachCallDynamicJava()->_vtable_index =
          call_java->as_CallDynamicJava()->_vtable_index;
     }
     else if( mcall->is_MachCallRuntime() ) {
       mcall->as_MachCallRuntime()->_name = call->as_CallRuntime()->_name;
     }
     msfpt = mcall;
   }
   // This is a non-call safepoint
   else {
     call = NULL;
     domain = NULL;
     MachNode *mn = match_tree(sfpt);
     if (C->failing())  return NULL;
     msfpt = mn->as_MachSafePoint();
     cnt = TypeFunc::Parms;
   }
   // Advertise the correct memory effects (for anti-dependence computation).
   msfpt->set_adr_type(sfpt->adr_type());
   // Allocate a private array of RegMasks.  These RegMasks are not shared.
   msfpt->_in_rms = NEW_RESOURCE_ARRAY( RegMask, cnt );
   // Empty them all.
   memset( msfpt->_in_rms, 0, sizeof(RegMask)*cnt );
   // Do all the pre-defined non-Empty register masks
   msfpt->_in_rms[TypeFunc::ReturnAdr] = _return_addr_mask;
   msfpt->_in_rms[TypeFunc::FramePtr ] = c_frame_ptr_mask;
   // Place first outgoing argument can possibly be put.
   OptoReg::Name begin_out_arg_area = OptoReg::add(_new_SP, C->out_preserve_stack_slots());
   assert( is_even(begin_out_arg_area), "" );
   // Compute max outgoing register number per call site.
   OptoReg::Name out_arg_limit_per_call = begin_out_arg_area;
   // Calls to C may hammer extra stack slots above and beyond any arguments.
   // These are usually backing store for register arguments for varargs.
   if( call != NULL && call->is_CallRuntime() )
     out_arg_limit_per_call = OptoReg::add(out_arg_limit_per_call,C->varargs_C_out_slots_killed());
   // Do the normal argument list (parameters) register masks
   int argcnt = cnt - TypeFunc::Parms;
   if( argcnt > 0 ) {          // Skip it all if we have no args
     BasicType *sig_bt  = NEW_RESOURCE_ARRAY( BasicType, argcnt );
     VMRegPair *parm_regs = NEW_RESOURCE_ARRAY( VMRegPair, argcnt );
     int i;
     for( i = 0; i < argcnt; i++ ) {
       sig_bt[i] = domain->field_at(i+TypeFunc::Parms)->basic_type();
     }
     // V-call to pick proper calling convention
     call->calling_convention( sig_bt, parm_regs, argcnt );
 #ifdef ASSERT
     // Sanity check users' calling convention.  Really handy during
     // the initial porting effort.  Fairly expensive otherwise.
     { for (int i = 0; i<argcnt; i++) {
       if( !parm_regs[i].first()->is_valid() &&
           !parm_regs[i].second()->is_valid() ) continue;
       VMReg reg1 = parm_regs[i].first();
       VMReg reg2 = parm_regs[i].second();
       for (int j = 0; j < i; j++) {
         if( !parm_regs[j].first()->is_valid() &&
             !parm_regs[j].second()->is_valid() ) continue;
         VMReg reg3 = parm_regs[j].first();
         VMReg reg4 = parm_regs[j].second();
         if( !reg1->is_valid() ) {
           assert( !reg2->is_valid(), "valid halvsies" );
         } else if( !reg3->is_valid() ) {
           assert( !reg4->is_valid(), "valid halvsies" );
         } else {
           assert( reg1 != reg2, "calling conv. must produce distinct regs");
           assert( reg1 != reg3, "calling conv. must produce distinct regs");
           assert( reg1 != reg4, "calling conv. must produce distinct regs");
           assert( reg2 != reg3, "calling conv. must produce distinct regs");
           assert( reg2 != reg4 || !reg2->is_valid(), "calling conv. must produce distinct regs");
           assert( reg3 != reg4, "calling conv. must produce distinct regs");
         }
       }
     }
     }
 #endif
     // Visit each argument.  Compute its outgoing register mask.
     // Return results now can have 2 bits returned.
     // Compute max over all outgoing arguments both per call-site
     // and over the entire method.
     for( i = 0; i < argcnt; i++ ) {
       // Address of incoming argument mask to fill in
       RegMask *rm = &mcall->_in_rms[i+TypeFunc::Parms];
       if( !parm_regs[i].first()->is_valid() &&
           !parm_regs[i].second()->is_valid() ) {
         continue;               // Avoid Halves
       }
       // Grab first register, adjust stack slots and insert in mask.
       OptoReg::Name reg1 = warp_outgoing_stk_arg(parm_regs[i].first(), begin_out_arg_area, out_arg_limit_per_call );
       if (OptoReg::is_valid(reg1))
         rm->Insert( reg1 );
       // Grab second register (if any), adjust stack slots and insert in mask.
       OptoReg::Name reg2 = warp_outgoing_stk_arg(parm_regs[i].second(), begin_out_arg_area, out_arg_limit_per_call );
       if (OptoReg::is_valid(reg2))
         rm->Insert( reg2 );
     } // End of for all arguments
     // Compute number of stack slots needed to restore stack in case of
     // Pascal-style argument popping.
     mcall->_argsize = out_arg_limit_per_call - begin_out_arg_area;
   }
   if (is_method_handle_invoke) {
     // Kill some extra stack space in case method handles want to do
     // a little in-place argument insertion.
     int regs_per_word  = NOT_LP64(1) LP64_ONLY(2); // %%% make a global const!
     out_arg_limit_per_call += MethodHandlePushLimit * regs_per_word;
     // Do not update mcall->_argsize because (a) the extra space is not
     // pushed as arguments and (b) _argsize is dead (not used anywhere).
   }
   // Compute the max stack slot killed by any call.  These will not be
   // available for debug info, and will be used to adjust FIRST_STACK_mask
   // after all call sites have been visited.
   if( _out_arg_limit < out_arg_limit_per_call)
     _out_arg_limit = out_arg_limit_per_call;
   if (mcall) {
     // Kill the outgoing argument area, including any non-argument holes and
     // any legacy C-killed slots.  Use Fat-Projections to do the killing.
     // Since the max-per-method covers the max-per-call-site and debug info
     // is excluded on the max-per-method basis, debug info cannot land in
     // this killed area.
     uint r_cnt = mcall->tf()->range()->cnt();
     MachProjNode *proj = new (C, 1) MachProjNode( mcall, r_cnt+10000, RegMask::Empty, MachProjNode::fat_proj );
     if (!RegMask::can_represent(OptoReg::Name(out_arg_limit_per_call-1))) {
       C->record_method_not_compilable_all_tiers("unsupported outgoing calling sequence");
     } else {
       for (int i = begin_out_arg_area; i < out_arg_limit_per_call; i++)
         proj->_rout.Insert(OptoReg::Name(i));
     }
     if( proj->_rout.is_NotEmpty() )
       _proj_list.push(proj);
   }
   // Transfer the safepoint information from the call to the mcall
   // Move the JVMState list
   msfpt->set_jvms(sfpt->jvms());
   for (JVMState* jvms = msfpt->jvms(); jvms; jvms = jvms->caller()) {
     jvms->set_map(sfpt);
   }
   // Debug inputs begin just after the last incoming parameter
   assert( (mcall == NULL) || (mcall->jvms() == NULL) ||
           (mcall->jvms()->debug_start() + mcall->_jvmadj == mcall->tf()->domain()->cnt()), "" );
   // Move the OopMap
   msfpt->_oop_map = sfpt->_oop_map;
   // Registers killed by the call are set in the local scheduling pass
   // of Global Code Motion.
   return msfpt;
 }
 //---------------------------match_tree----------------------------------------
 // Match a Ideal Node DAG - turn it into a tree; Label & Reduce.  Used as part
 // of the whole-sale conversion from Ideal to Mach Nodes.  Also used for
 // making GotoNodes while building the CFG and in init_spill_mask() to identify
 // a Load's result RegMask for memoization in idealreg2regmask[]
 MachNode *Matcher::match_tree( const Node *n ) {
   assert( n->Opcode() != Op_Phi, "cannot match" );
   assert( !n->is_block_start(), "cannot match" );
   // Set the mark for all locally allocated State objects.
   // When this call returns, the _states_arena arena will be reset
   // freeing all State objects.
   ResourceMark rm( &_states_arena );
   LabelRootDepth = 0;
   // StoreNodes require their Memory input to match any LoadNodes
   Node *mem = n->is_Store() ? n->in(MemNode::Memory) : (Node*)1 ;
 #ifdef ASSERT
   Node* save_mem_node = _mem_node;
   _mem_node = n->is_Store() ? (Node*)n : NULL;
 #endif
   // State object for root node of match tree
   // Allocate it on _states_arena - stack allocation can cause stack overflow.
   State *s = new (&_states_arena) State;
   s->_kids[0] = NULL;
   s->_kids[1] = NULL;
   s->_leaf = (Node*)n;
   // Label the input tree, allocating labels from top-level arena
   Label_Root( n, s, n->in(0), mem );
   if (C->failing())  return NULL;
   // The minimum cost match for the whole tree is found at the root State
   uint mincost = max_juint;
   uint cost = max_juint;
   uint i;
   for( i = 0; i < NUM_OPERANDS; i++ ) {
     if( s->valid(i) &&                // valid entry and
         s->_cost[i] < cost &&         // low cost and
         s->_rule[i] >= NUM_OPERANDS ) // not an operand
       cost = s->_cost[mincost=i];
   }
   if (mincost == max_juint) {
 #ifndef PRODUCT
     tty->print("No matching rule for:");
     s->dump();
 #endif
     Matcher::soft_match_failure();
     return NULL;
   }
   // Reduce input tree based upon the state labels to machine Nodes
   MachNode *m = ReduceInst( s, s->_rule[mincost], mem );
 #ifdef ASSERT
   _old2new_map.map(n->_idx, m);
   _new2old_map.map(m->_idx, (Node*)n);
 #endif
   // Add any Matcher-ignored edges
   uint cnt = n->req();
   uint start = 1;
   if( mem != (Node*)1 ) start = MemNode::Memory+1;
   if( n->is_AddP() ) {
     assert( mem == (Node*)1, "" );
     start = AddPNode::Base+1;
   }
   for( i = start; i < cnt; i++ ) {
     if( !n->match_edge(i) ) {
       if( i < m->req() )
         m->ins_req( i, n->in(i) );
       else
         m->add_req( n->in(i) );
     }
   }
   debug_only( _mem_node = save_mem_node; )
   return m;
 }
 //------------------------------match_into_reg---------------------------------
 // Choose to either match this Node in a register or part of the current
 // match tree.  Return true for requiring a register and false for matching
 // as part of the current match tree.
 static bool match_into_reg( const Node *n, Node *m, Node *control, int i, bool shared ) {
   const Type *t = m->bottom_type();
   if( t->singleton() ) {
     // Never force constants into registers.  Allow them to match as
     // constants or registers.  Copies of the same value will share
     // the same register.  See find_shared_node.
     return false;
   } else {                      // Not a constant
     // Stop recursion if they have different Controls.
     // Slot 0 of constants is not really a Control.
     if( control && m->in(0) && control != m->in(0) ) {
       // Actually, we can live with the most conservative control we
       // find, if it post-dominates the others.  This allows us to
       // pick up load/op/store trees where the load can float a little
       // above the store.
       Node *x = control;
       const uint max_scan = 6;   // Arbitrary scan cutoff
       uint j;
       for( j=0; j<max_scan; j++ ) {
         if( x->is_Region() )    // Bail out at merge points
           return true;
         x = x->in(0);
         if( x == m->in(0) )     // Does 'control' post-dominate
           break;                // m->in(0)?  If so, we can use it
       }
       if( j == max_scan )       // No post-domination before scan end?
         return true;            // Then break the match tree up
     }
     if (m->is_DecodeN() && Matcher::clone_shift_expressions) {
       // These are commonly used in address expressions and can
       // efficiently fold into them on X64 in some cases.
       return false;
     }
   }
   // Not forceable cloning.  If shared, put it into a register.
   return shared;
 }
 //------------------------------Instruction Selection--------------------------
 // Label method walks a "tree" of nodes, using the ADLC generated DFA to match
 // ideal nodes to machine instructions.  Trees are delimited by shared Nodes,
 // things the Matcher does not match (e.g., Memory), and things with different
 // Controls (hence forced into different blocks).  We pass in the Control
 // selected for this entire State tree.
 // The Matcher works on Trees, but an Intel add-to-memory requires a DAG: the
 // Store and the Load must have identical Memories (as well as identical
 // pointers).  Since the Matcher does not have anything for Memory (and
 // does not handle DAGs), I have to match the Memory input myself.  If the
 // Tree root is a Store, I require all Loads to have the identical memory.
 Node *Matcher::Label_Root( const Node *n, State *svec, Node *control, const Node *mem){
   // Since Label_Root is a recursive function, its possible that we might run
   // out of stack space.  See bugs 6272980 & 6227033 for more info.
   LabelRootDepth++;
   if (LabelRootDepth > MaxLabelRootDepth) {
     C->record_method_not_compilable_all_tiers("Out of stack space, increase MaxLabelRootDepth");
     return NULL;
   }
   uint care = 0;                // Edges matcher cares about
   uint cnt = n->req();
   uint i = 0;
   // Examine children for memory state
   // Can only subsume a child into your match-tree if that child's memory state
   // is not modified along the path to another input.
   // It is unsafe even if the other inputs are separate roots.
   Node *input_mem = NULL;
   for( i = 1; i < cnt; i++ ) {
     if( !n->match_edge(i) ) continue;
     Node *m = n->in(i);         // Get ith input
     assert( m, "expect non-null children" );
     if( m->is_Load() ) {
       if( input_mem == NULL ) {
         input_mem = m->in(MemNode::Memory);
       } else if( input_mem != m->in(MemNode::Memory) ) {
         input_mem = NodeSentinel;
       }
     }
   }
   for( i = 1; i < cnt; i++ ){// For my children
     if( !n->match_edge(i) ) continue;
     Node *m = n->in(i);         // Get ith input
     // Allocate states out of a private arena
     State *s = new (&_states_arena) State;
     svec->_kids[care++] = s;
     assert( care <= 2, "binary only for now" );
     // Recursively label the State tree.
     s->_kids[0] = NULL;
     s->_kids[1] = NULL;
     s->_leaf = m;
     // Check for leaves of the State Tree; things that cannot be a part of
     // the current tree.  If it finds any, that value is matched as a
     // register operand.  If not, then the normal matching is used.
     if( match_into_reg(n, m, control, i, is_shared(m)) ||
         //
         // Stop recursion if this is LoadNode and the root of this tree is a
         // StoreNode and the load & store have different memories.
         ((mem!=(Node*)1) && m->is_Load() && m->in(MemNode::Memory) != mem) ||
         // Can NOT include the match of a subtree when its memory state
         // is used by any of the other subtrees
         (input_mem == NodeSentinel) ) {
 #ifndef PRODUCT
       // Print when we exclude matching due to different memory states at input-loads
       if( PrintOpto && (Verbose && WizardMode) && (input_mem == NodeSentinel)
         && !((mem!=(Node*)1) && m->is_Load() && m->in(MemNode::Memory) != mem) ) {
         tty->print_cr("invalid input_mem");
       }
 #endif
       // Switch to a register-only opcode; this value must be in a register
       // and cannot be subsumed as part of a larger instruction.
       s->DFA( m->ideal_reg(), m );
     } else {
       // If match tree has no control and we do, adopt it for entire tree
       if( control == NULL && m->in(0) != NULL && m->req() > 1 )
         control = m->in(0);         // Pick up control
       // Else match as a normal part of the match tree.
       control = Label_Root(m,s,control,mem);
       if (C->failing()) return NULL;
     }
   }
   // Call DFA to match this node, and return
   svec->DFA( n->Opcode(), n );
 #ifdef ASSERT
   uint x;
   for( x = 0; x < _LAST_MACH_OPER; x++ )
     if( svec->valid(x) )
       break;
   if (x >= _LAST_MACH_OPER) {
     n->dump();
     svec->dump();
     assert( false, "bad AD file" );
   }
 #endif
   return control;
 }
 // Con nodes reduced using the same rule can share their MachNode
 // which reduces the number of copies of a constant in the final
 // program.  The register allocator is free to split uses later to
 // split live ranges.
 MachNode* Matcher::find_shared_node(Node* leaf, uint rule) {
   if (!leaf->is_Con() && !leaf->is_DecodeN()) return NULL;
   // See if this Con has already been reduced using this rule.
   if (_shared_nodes.Size() <= leaf->_idx) return NULL;
   MachNode* last = (MachNode*)_shared_nodes.at(leaf->_idx);
   if (last != NULL && rule == last->rule()) {
     // Don't expect control change for DecodeN
     if (leaf->is_DecodeN())
       return last;
     // Get the new space root.
     Node* xroot = new_node(C->root());
     if (xroot == NULL) {
       // This shouldn't happen give the order of matching.
       return NULL;
     }
     // Shared constants need to have their control be root so they
     // can be scheduled properly.
     Node* control = last->in(0);
     if (control != xroot) {
       if (control == NULL || control == C->root()) {
         last->set_req(0, xroot);
       } else {
         assert(false, "unexpected control");
         return NULL;
       }
     }
     return last;
   }
   return NULL;
 }
 //------------------------------ReduceInst-------------------------------------
 // Reduce a State tree (with given Control) into a tree of MachNodes.
 // This routine (and it's cohort ReduceOper) convert Ideal Nodes into
 // complicated machine Nodes.  Each MachNode covers some tree of Ideal Nodes.
 // Each MachNode has a number of complicated MachOper operands; each
 // MachOper also covers a further tree of Ideal Nodes.
 // The root of the Ideal match tree is always an instruction, so we enter
 // the recursion here.  After building the MachNode, we need to recurse
 // the tree checking for these cases:
 // (1) Child is an instruction -
 //     Build the instruction (recursively), add it as an edge.
 //     Build a simple operand (register) to hold the result of the instruction.
 // (2) Child is an interior part of an instruction -
 //     Skip over it (do nothing)
 // (3) Child is the start of a operand -
 //     Build the operand, place it inside the instruction
 //     Call ReduceOper.
 MachNode *Matcher::ReduceInst( State *s, int rule, Node *&mem ) {
   assert( rule >= NUM_OPERANDS, "called with operand rule" );
   MachNode* shared_node = find_shared_node(s->_leaf, rule);
   if (shared_node != NULL) {
     return shared_node;
   }
   // Build the object to represent this state & prepare for recursive calls
   MachNode *mach = s->MachNodeGenerator( rule, C );
   mach->_opnds[0] = s->MachOperGenerator( _reduceOp[rule], C );
   assert( mach->_opnds[0] != NULL, "Missing result operand" );
   Node *leaf = s->_leaf;
   // Check for instruction or instruction chain rule
   if( rule >= _END_INST_CHAIN_RULE || rule < _BEGIN_INST_CHAIN_RULE ) {
     assert(C->node_arena()->contains(s->_leaf) || !has_new_node(s->_leaf),
            "duplicating node that's already been matched");
     // Instruction
     mach->add_req( leaf->in(0) ); // Set initial control
     // Reduce interior of complex instruction
     ReduceInst_Interior( s, rule, mem, mach, 1 );
   } else {
     // Instruction chain rules are data-dependent on their inputs
     mach->add_req(0);             // Set initial control to none
     ReduceInst_Chain_Rule( s, rule, mem, mach );
   }
   // If a Memory was used, insert a Memory edge
   if( mem != (Node*)1 ) {
     mach->ins_req(MemNode::Memory,mem);
 #ifdef ASSERT
     // Verify adr type after matching memory operation
     const MachOper* oper = mach->memory_operand();
     if (oper != NULL && oper != (MachOper*)-1) {
       // It has a unique memory operand.  Find corresponding ideal mem node.
       Node* m = NULL;
       if (leaf->is_Mem()) {
         m = leaf;
       } else {
         m = _mem_node;
         assert(m != NULL && m->is_Mem(), "expecting memory node");
       }
       const Type* mach_at = mach->adr_type();
       // DecodeN node consumed by an address may have different type
       // then its input. Don't compare types for such case.
       if (m->adr_type() != mach_at &&
           (m->in(MemNode::Address)->is_DecodeN() ||
            m->in(MemNode::Address)->is_AddP() &&
            m->in(MemNode::Address)->in(AddPNode::Address)->is_DecodeN() ||
            m->in(MemNode::Address)->is_AddP() &&
            m->in(MemNode::Address)->in(AddPNode::Address)->is_AddP() &&
            m->in(MemNode::Address)->in(AddPNode::Address)->in(AddPNode::Address)->is_DecodeN())) {
         mach_at = m->adr_type();
       }
       if (m->adr_type() != mach_at) {
         m->dump();
         tty->print_cr("mach:");
         mach->dump(1);
       }
       assert(m->adr_type() == mach_at, "matcher should not change adr type");
     }
 #endif
   }
   // If the _leaf is an AddP, insert the base edge
   if( leaf->is_AddP() )
     mach->ins_req(AddPNode::Base,leaf->in(AddPNode::Base));
   uint num_proj = _proj_list.size();
   // Perform any 1-to-many expansions required
   MachNode *ex = mach->Expand(s,_proj_list);
   if( ex != mach ) {
     assert(ex->ideal_reg() == mach->ideal_reg(), "ideal types should match");
     if( ex->in(1)->is_Con() )
       ex->in(1)->set_req(0, C->root());
     // Remove old node from the graph
     for( uint i=0; i<mach->req(); i++ ) {
       mach->set_req(i,NULL);
     }
 #ifdef ASSERT
     _new2old_map.map(ex->_idx, s->_leaf);
 #endif
   }
   // PhaseChaitin::fixup_spills will sometimes generate spill code
   // via the matcher.  By the time, nodes have been wired into the CFG,
   // and any further nodes generated by expand rules will be left hanging
   // in space, and will not get emitted as output code.  Catch this.
   // Also, catch any new register allocation constraints ("projections")
   // generated belatedly during spill code generation.
   if (_allocation_started) {
     guarantee(ex == mach, "no expand rules during spill generation");
     guarantee(_proj_list.size() == num_proj, "no allocation during spill generation");
   }
   if (leaf->is_Con() || leaf->is_DecodeN()) {
     // Record the con for sharing
     _shared_nodes.map(leaf->_idx, ex);
   }
   return ex;
 }
 void Matcher::ReduceInst_Chain_Rule( State *s, int rule, Node *&mem, MachNode *mach ) {
   // 'op' is what I am expecting to receive
   int op = _leftOp[rule];
   // Operand type to catch childs result
   // This is what my child will give me.
   int opnd_class_instance = s->_rule[op];
   // Choose between operand class or not.
   // This is what I will receive.
   int catch_op = (FIRST_OPERAND_CLASS <= op && op < NUM_OPERANDS) ? opnd_class_instance : op;
   // New rule for child.  Chase operand classes to get the actual rule.
   int newrule = s->_rule[catch_op];
   if( newrule < NUM_OPERANDS ) {
     // Chain from operand or operand class, may be output of shared node
     assert( 0 <= opnd_class_instance && opnd_class_instance < NUM_OPERANDS,
             "Bad AD file: Instruction chain rule must chain from operand");
     // Insert operand into array of operands for this instruction
     mach->_opnds[1] = s->MachOperGenerator( opnd_class_instance, C );
     ReduceOper( s, newrule, mem, mach );
   } else {
     // Chain from the result of an instruction
     assert( newrule >= _LAST_MACH_OPER, "Do NOT chain from internal operand");
     mach->_opnds[1] = s->MachOperGenerator( _reduceOp[catch_op], C );
     Node *mem1 = (Node*)1;
     debug_only(Node *save_mem_node = _mem_node;)
     mach->add_req( ReduceInst(s, newrule, mem1) );
     debug_only(_mem_node = save_mem_node;)
   }
   return;
 }
 uint Matcher::ReduceInst_Interior( State *s, int rule, Node *&mem, MachNode *mach, uint num_opnds ) {
   if( s->_leaf->is_Load() ) {
     Node *mem2 = s->_leaf->in(MemNode::Memory);
     assert( mem == (Node*)1 || mem == mem2, "multiple Memories being matched at once?" );
     debug_only( if( mem == (Node*)1 ) _mem_node = s->_leaf;)
     mem = mem2;
   }
   if( s->_leaf->in(0) != NULL && s->_leaf->req() > 1) {
     if( mach->in(0) == NULL )
       mach->set_req(0, s->_leaf->in(0));
   }
   // Now recursively walk the state tree & add operand list.
   for( uint i=0; i<2; i++ ) {   // binary tree
     State *newstate = s->_kids[i];
     if( newstate == NULL ) break;      // Might only have 1 child
     // 'op' is what I am expecting to receive
     int op;
     if( i == 0 ) {
       op = _leftOp[rule];
     } else {
       op = _rightOp[rule];
     }
     // Operand type to catch childs result
     // This is what my child will give me.
     int opnd_class_instance = newstate->_rule[op];
     // Choose between operand class or not.
     // This is what I will receive.
     int catch_op = (op >= FIRST_OPERAND_CLASS && op < NUM_OPERANDS) ? opnd_class_instance : op;
     // New rule for child.  Chase operand classes to get the actual rule.
     int newrule = newstate->_rule[catch_op];
     if( newrule < NUM_OPERANDS ) { // Operand/operandClass or internalOp/instruction?
       // Operand/operandClass
       // Insert operand into array of operands for this instruction
       mach->_opnds[num_opnds++] = newstate->MachOperGenerator( opnd_class_instance, C );
       ReduceOper( newstate, newrule, mem, mach );
     } else {                    // Child is internal operand or new instruction
       if( newrule < _LAST_MACH_OPER ) { // internal operand or instruction?
         // internal operand --> call ReduceInst_Interior
         // Interior of complex instruction.  Do nothing but recurse.
         num_opnds = ReduceInst_Interior( newstate, newrule, mem, mach, num_opnds );
       } else {
         // instruction --> call build operand(  ) to catch result
         //             --> ReduceInst( newrule )
         mach->_opnds[num_opnds++] = s->MachOperGenerator( _reduceOp[catch_op], C );
         Node *mem1 = (Node*)1;
         debug_only(Node *save_mem_node = _mem_node;)
         mach->add_req( ReduceInst( newstate, newrule, mem1 ) );
         debug_only(_mem_node = save_mem_node;)
       }
     }
     assert( mach->_opnds[num_opnds-1], "" );
   }
   return num_opnds;
 }
 // This routine walks the interior of possible complex operands.
 // At each point we check our children in the match tree:
 // (1) No children -
 //     We are a leaf; add _leaf field as an input to the MachNode
 // (2) Child is an internal operand -
 //     Skip over it ( do nothing )
 // (3) Child is an instruction -
 //     Call ReduceInst recursively and
 //     and instruction as an input to the MachNode
 void Matcher::ReduceOper( State *s, int rule, Node *&mem, MachNode *mach ) {
   assert( rule < _LAST_MACH_OPER, "called with operand rule" );
   State *kid = s->_kids[0];
   assert( kid == NULL || s->_leaf->in(0) == NULL, "internal operands have no control" );
   // Leaf?  And not subsumed?
   if( kid == NULL && !_swallowed[rule] ) {
     mach->add_req( s->_leaf );  // Add leaf pointer
     return;                     // Bail out
   }
   if( s->_leaf->is_Load() ) {
     assert( mem == (Node*)1, "multiple Memories being matched at once?" );
     mem = s->_leaf->in(MemNode::Memory);
     debug_only(_mem_node = s->_leaf;)
   }
   if( s->_leaf->in(0) && s->_leaf->req() > 1) {
     if( !mach->in(0) )
       mach->set_req(0,s->_leaf->in(0));
     else {
       assert( s->_leaf->in(0) == mach->in(0), "same instruction, differing controls?" );
     }
   }
   for( uint i=0; kid != NULL && i<2; kid = s->_kids[1], i++ ) {   // binary tree
     int newrule;
     if( i == 0 )
       newrule = kid->_rule[_leftOp[rule]];
     else
       newrule = kid->_rule[_rightOp[rule]];
     if( newrule < _LAST_MACH_OPER ) { // Operand or instruction?
       // Internal operand; recurse but do nothing else
       ReduceOper( kid, newrule, mem, mach );
     } else {                    // Child is a new instruction
       // Reduce the instruction, and add a direct pointer from this
       // machine instruction to the newly reduced one.
       Node *mem1 = (Node*)1;
       debug_only(Node *save_mem_node = _mem_node;)
       mach->add_req( ReduceInst( kid, newrule, mem1 ) );
       debug_only(_mem_node = save_mem_node;)
     }
   }
 }
 // -------------------------------------------------------------------------
 // Java-Java calling convention
 // (what you use when Java calls Java)
 //------------------------------find_receiver----------------------------------
 // For a given signature, return the OptoReg for parameter 0.
 OptoReg::Name Matcher::find_receiver( bool is_outgoing ) {
   VMRegPair regs;
   BasicType sig_bt = T_OBJECT;
   calling_convention(&sig_bt, &regs, 1, is_outgoing);
   // Return argument 0 register.  In the LP64 build pointers
   // take 2 registers, but the VM wants only the 'main' name.
   return OptoReg::as_OptoReg(regs.first());
 }
 // A method-klass-holder may be passed in the inline_cache_reg
 // and then expanded into the inline_cache_reg and a method_oop register
 //   defined in ad_<arch>.cpp
 //------------------------------find_shared------------------------------------
 // Set bits if Node is shared or otherwise a root
 void Matcher::find_shared( Node *n ) {
   // Allocate stack of size C->unique() * 2 to avoid frequent realloc
   MStack mstack(C->unique() * 2);
   // Mark nodes as address_visited if they are inputs to an address expression
   VectorSet address_visited(Thread::current()->resource_area());
   mstack.push(n, Visit);     // Don't need to pre-visit root node
   while (mstack.is_nonempty()) {
     n = mstack.node();       // Leave node on stack
     Node_State nstate = mstack.state();
     uint nop = n->Opcode();
     if (nstate == Pre_Visit) {
       if (address_visited.test(n->_idx)) { // Visited in address already?
         // Flag as visited and shared now.
         set_visited(n);
       }
       if (is_visited(n)) {   // Visited already?
         // Node is shared and has no reason to clone.  Flag it as shared.
         // This causes it to match into a register for the sharing.
         set_shared(n);       // Flag as shared and
         mstack.pop();        // remove node from stack
         continue;
       }
       nstate = Visit; // Not already visited; so visit now
     }
     if (nstate == Visit) {
       mstack.set_state(Post_Visit);
       set_visited(n);   // Flag as visited now
       bool mem_op = false;
       switch( nop ) {  // Handle some opcodes special
       case Op_Phi:             // Treat Phis as shared roots
       case Op_Parm:
       case Op_Proj:            // All handled specially during matching
       case Op_SafePointScalarObject:
         set_shared(n);
         set_dontcare(n);
         break;
       case Op_If:
       case Op_CountedLoopEnd:
         mstack.set_state(Alt_Post_Visit); // Alternative way
         // Convert (If (Bool (CmpX A B))) into (If (Bool) (CmpX A B)).  Helps
         // with matching cmp/branch in 1 instruction.  The Matcher needs the
         // Bool and CmpX side-by-side, because it can only get at constants
         // that are at the leaves of Match trees, and the Bool's condition acts
         // as a constant here.
         mstack.push(n->in(1), Visit);         // Clone the Bool
         mstack.push(n->in(0), Pre_Visit);     // Visit control input
         continue; // while (mstack.is_nonempty())
       case Op_ConvI2D:         // These forms efficiently match with a prior
       case Op_ConvI2F:         //   Load but not a following Store
         if( n->in(1)->is_Load() &&        // Prior load
             n->outcnt() == 1 &&           // Not already shared
             n->unique_out()->is_Store() ) // Following store
           set_shared(n);       // Force it to be a root
         break;
       case Op_ReverseBytesI:
       case Op_ReverseBytesL:
         if( n->in(1)->is_Load() &&        // Prior load
             n->outcnt() == 1 )            // Not already shared
           set_shared(n);                  // Force it to be a root
         break;
       case Op_BoxLock:         // Cant match until we get stack-regs in ADLC
       case Op_IfFalse:
       case Op_IfTrue:
       case Op_MachProj:
       case Op_MergeMem:
       case Op_Catch:
       case Op_CatchProj:
       case Op_CProj:
       case Op_JumpProj:
       case Op_JProj:
       case Op_NeverBranch:
         set_dontcare(n);
         break;
       case Op_Jump:
         mstack.push(n->in(1), Visit);         // Switch Value
         mstack.push(n->in(0), Pre_Visit);     // Visit Control input
         continue;                             // while (mstack.is_nonempty())
       case Op_StrComp:
       case Op_StrEquals:
       case Op_StrIndexOf:
       case Op_AryEq:
         set_shared(n); // Force result into register (it will be anyways)
         break;
       case Op_ConP: {  // Convert pointers above the centerline to NUL
         TypeNode *tn = n->as_Type(); // Constants derive from type nodes
         const TypePtr* tp = tn->type()->is_ptr();
         if (tp->_ptr == TypePtr::AnyNull) {
           tn->set_type(TypePtr::NULL_PTR);
         }
         break;
       }
       case Op_ConN: {  // Convert narrow pointers above the centerline to NUL
         TypeNode *tn = n->as_Type(); // Constants derive from type nodes
         const TypePtr* tp = tn->type()->make_ptr();
         if (tp && tp->_ptr == TypePtr::AnyNull) {
           tn->set_type(TypeNarrowOop::NULL_PTR);
         }
         break;
       }
       case Op_Binary:         // These are introduced in the Post_Visit state.
         ShouldNotReachHere();
         break;
       case Op_ClearArray:
       case Op_SafePoint:
         mem_op = true;
         break;
       default:
         if( n->is_Store() ) {
           // Do match stores, despite no ideal reg
           mem_op = true;
           break;
         }
         if( n->is_Mem() ) { // Loads and LoadStores
           mem_op = true;
           // Loads must be root of match tree due to prior load conflict
           if( C->subsume_loads() == false )
             set_shared(n);
         }
         // Fall into default case
         if( !n->ideal_reg() )
           set_dontcare(n);  // Unmatchable Nodes
       } // end_switch
       for(int i = n->req() - 1; i >= 0; --i) { // For my children
         Node *m = n->in(i); // Get ith input
         if (m == NULL) continue;  // Ignore NULLs
         uint mop = m->Opcode();
         // Must clone all producers of flags, or we will not match correctly.
         // Suppose a compare setting int-flags is shared (e.g., a switch-tree)
         // then it will match into an ideal Op_RegFlags.  Alas, the fp-flags
         // are also there, so we may match a float-branch to int-flags and
         // expect the allocator to haul the flags from the int-side to the
         // fp-side.  No can do.
         if( _must_clone[mop] ) {
           mstack.push(m, Visit);
           continue; // for(int i = ...)
         }
         if( mop == Op_AddP && m->in(AddPNode::Base)->Opcode() == Op_DecodeN ) {
           // Bases used in addresses must be shared but since
           // they are shared through a DecodeN they may appear
           // to have a single use so force sharing here.
           set_shared(m->in(AddPNode::Base)->in(1));
         }
         // Clone addressing expressions as they are "free" in memory access instructions
         if( mem_op && i == MemNode::Address && mop == Op_AddP ) {
           // Some inputs for address expression are not put on stack
           // to avoid marking them as shared and forcing them into register
           // if they are used only in address expressions.
           // But they should be marked as shared if there are other uses
           // besides address expressions.
           Node *off = m->in(AddPNode::Offset);
           if( off->is_Con() &&
               // When there are other uses besides address expressions
               // put it on stack and mark as shared.
               !is_visited(m) ) {
             address_visited.test_set(m->_idx); // Flag as address_visited
             Node *adr = m->in(AddPNode::Address);
             // Intel, ARM and friends can handle 2 adds in addressing mode
             if( clone_shift_expressions && adr->is_AddP() &&
                 // AtomicAdd is not an addressing expression.
                 // Cheap to find it by looking for screwy base.
                 !adr->in(AddPNode::Base)->is_top() &&
                 // Are there other uses besides address expressions?
                 !is_visited(adr) ) {
               address_visited.set(adr->_idx); // Flag as address_visited
               Node *shift = adr->in(AddPNode::Offset);
               // Check for shift by small constant as well
               if( shift->Opcode() == Op_LShiftX && shift->in(2)->is_Con() &&
                   shift->in(2)->get_int() <= 3 &&
                   // Are there other uses besides address expressions?
                   !is_visited(shift) ) {
                 address_visited.set(shift->_idx); // Flag as address_visited
                 mstack.push(shift->in(2), Visit);
                 Node *conv = shift->in(1);
 #ifdef _LP64
                 // Allow Matcher to match the rule which bypass
                 // ConvI2L operation for an array index on LP64
                 // if the index value is positive.
                 if( conv->Opcode() == Op_ConvI2L &&
                     conv->as_Type()->type()->is_long()->_lo >= 0 &&
                     // Are there other uses besides address expressions?
                     !is_visited(conv) ) {
                   address_visited.set(conv->_idx); // Flag as address_visited
                   mstack.push(conv->in(1), Pre_Visit);
                 } else
 #endif
                 mstack.push(conv, Pre_Visit);
               } else {
                 mstack.push(shift, Pre_Visit);
               }
               mstack.push(adr->in(AddPNode::Address), Pre_Visit);
               mstack.push(adr->in(AddPNode::Base), Pre_Visit);
             } else {  // Sparc, Alpha, PPC and friends
               mstack.push(adr, Pre_Visit);
             }
             // Clone X+offset as it also folds into most addressing expressions
             mstack.push(off, Visit);
             mstack.push(m->in(AddPNode::Base), Pre_Visit);
             continue; // for(int i = ...)
           } // if( off->is_Con() )
         }   // if( mem_op &&
         mstack.push(m, Pre_Visit);
       }     // for(int i = ...)
     }
     else if (nstate == Alt_Post_Visit) {
       mstack.pop(); // Remove node from stack
       // We cannot remove the Cmp input from the Bool here, as the Bool may be
       // shared and all users of the Bool need to move the Cmp in parallel.
       // This leaves both the Bool and the If pointing at the Cmp.  To
       // prevent the Matcher from trying to Match the Cmp along both paths
       // BoolNode::match_edge always returns a zero.
       // We reorder the Op_If in a pre-order manner, so we can visit without
       // accidentally sharing the Cmp (the Bool and the If make 2 users).
       n->add_req( n->in(1)->in(1) ); // Add the Cmp next to the Bool
     }
     else if (nstate == Post_Visit) {
       mstack.pop(); // Remove node from stack
       // Now hack a few special opcodes
       switch( n->Opcode() ) {       // Handle some opcodes special
       case Op_StorePConditional:
       case Op_StoreIConditional:
       case Op_StoreLConditional:
       case Op_CompareAndSwapI:
       case Op_CompareAndSwapL:
       case Op_CompareAndSwapP:
       case Op_CompareAndSwapN: {   // Convert trinary to binary-tree
         Node *newval = n->in(MemNode::ValueIn );
         Node *oldval  = n->in(LoadStoreNode::ExpectedIn);
         Node *pair = new (C, 3) BinaryNode( oldval, newval );
         n->set_req(MemNode::ValueIn,pair);
         n->del_req(LoadStoreNode::ExpectedIn);
         break;
       }
       case Op_CMoveD:              // Convert trinary to binary-tree
       case Op_CMoveF:
       case Op_CMoveI:
       case Op_CMoveL:
       case Op_CMoveN:
       case Op_CMoveP: {
         // Restructure into a binary tree for Matching.  It's possible that
         // we could move this code up next to the graph reshaping for IfNodes
         // or vice-versa, but I do not want to debug this for Ladybird.
         // 10/2/2000 CNC.
         Node *pair1 = new (C, 3) BinaryNode(n->in(1),n->in(1)->in(1));
         n->set_req(1,pair1);
         Node *pair2 = new (C, 3) BinaryNode(n->in(2),n->in(3));
         n->set_req(2,pair2);
         n->del_req(3);
         break;
       }
       case Op_StrEquals: {
         Node *pair1 = new (C, 3) BinaryNode(n->in(2),n->in(3));
         n->set_req(2,pair1);
         n->set_req(3,n->in(4));
         n->del_req(4);
         break;
       }
       case Op_StrComp:
       case Op_StrIndexOf: {
         Node *pair1 = new (C, 3) BinaryNode(n->in(2),n->in(3));
         n->set_req(2,pair1);
         Node *pair2 = new (C, 3) BinaryNode(n->in(4),n->in(5));
         n->set_req(3,pair2);
         n->del_req(5);
         n->del_req(4);
         break;
       }
       default:
         break;
       }
     }
     else {
       ShouldNotReachHere();
     }
   } // end of while (mstack.is_nonempty())
 }
 #ifdef ASSERT
 // machine-independent root to machine-dependent root
 void Matcher::dump_old2new_map() {
   _old2new_map.dump();
 }
 #endif
 //---------------------------collect_null_checks-------------------------------
 // Find null checks in the ideal graph; write a machine-specific node for
 // it.  Used by later implicit-null-check handling.  Actually collects
 // either an IfTrue or IfFalse for the common NOT-null path, AND the ideal
 // value being tested.
 void Matcher::collect_null_checks( Node *proj, Node *orig_proj ) {
   Node *iff = proj->in(0);
   if( iff->Opcode() == Op_If ) {
     // During matching If's have Bool & Cmp side-by-side
     BoolNode *b = iff->in(1)->as_Bool();
     Node *cmp = iff->in(2);
     int opc = cmp->Opcode();
     if (opc != Op_CmpP && opc != Op_CmpN) return;
     const Type* ct = cmp->in(2)->bottom_type();
     if (ct == TypePtr::NULL_PTR ||
         (opc == Op_CmpN && ct == TypeNarrowOop::NULL_PTR)) {
       bool push_it = false;
       if( proj->Opcode() == Op_IfTrue ) {
         extern int all_null_checks_found;
         all_null_checks_found++;
         if( b->_test._test == BoolTest::ne ) {
           push_it = true;
         }
       } else {
         assert( proj->Opcode() == Op_IfFalse, "" );
         if( b->_test._test == BoolTest::eq ) {
           push_it = true;
         }
       }
       if( push_it ) {
         _null_check_tests.push(proj);
         Node* val = cmp->in(1);
 #ifdef _LP64
         if (UseCompressedOops && !Matcher::clone_shift_expressions &&
             val->bottom_type()->isa_narrowoop()) {
           //
           // Look for DecodeN node which should be pinned to orig_proj.
           // On platforms (Sparc) which can not handle 2 adds
           // in addressing mode we have to keep a DecodeN node and
           // use it to do implicit NULL check in address.
           //
           // DecodeN node was pinned to non-null path (orig_proj) during
           // CastPP transformation in final_graph_reshaping_impl().
           //
           uint cnt = orig_proj->outcnt();
           for (uint i = 0; i < orig_proj->outcnt(); i++) {
             Node* d = orig_proj->raw_out(i);
             if (d->is_DecodeN() && d->in(1) == val) {
               val = d;
               val->set_req(0, NULL); // Unpin now.
               break;
             }
           }
         }
 #endif
         _null_check_tests.push(val);
       }
     }
   }
 }
 //---------------------------validate_null_checks------------------------------
 // Its possible that the value being NULL checked is not the root of a match
 // tree.  If so, I cannot use the value in an implicit null check.
 void Matcher::validate_null_checks( ) {
   uint cnt = _null_check_tests.size();
   for( uint i=0; i < cnt; i+=2 ) {
     Node *test = _null_check_tests[i];
     Node *val = _null_check_tests[i+1];
     if (has_new_node(val)) {
       // Is a match-tree root, so replace with the matched value
       _null_check_tests.map(i+1, new_node(val));
     } else {
       // Yank from candidate list
       _null_check_tests.map(i+1,_null_check_tests[--cnt]);
       _null_check_tests.map(i,_null_check_tests[--cnt]);
       _null_check_tests.pop();
       _null_check_tests.pop();
       i-=2;
     }
   }
 }
 // Used by the DFA in dfa_sparc.cpp.  Check for a prior FastLock
 // acting as an Acquire and thus we don't need an Acquire here.  We
 // retain the Node to act as a compiler ordering barrier.
 bool Matcher::prior_fast_lock( const Node *acq ) {
   Node *r = acq->in(0);
   if( !r->is_Region() || r->req() <= 1 ) return false;
   Node *proj = r->in(1);
   if( !proj->is_Proj() ) return false;
   Node *call = proj->in(0);
   if( !call->is_Call() || call->as_Call()->entry_point() != OptoRuntime::complete_monitor_locking_Java() )
     return false;
   return true;
 }
 // Used by the DFA in dfa_sparc.cpp.  Check for a following FastUnLock
 // acting as a Release and thus we don't need a Release here.  We
 // retain the Node to act as a compiler ordering barrier.
 bool Matcher::post_fast_unlock( const Node *rel ) {
   Compile *C = Compile::current();
   assert( rel->Opcode() == Op_MemBarRelease, "" );
   const MemBarReleaseNode *mem = (const MemBarReleaseNode*)rel;
   DUIterator_Fast imax, i = mem->fast_outs(imax);
   Node *ctrl = NULL;
   while( true ) {
     ctrl = mem->fast_out(i);            // Throw out-of-bounds if proj not found
     assert( ctrl->is_Proj(), "only projections here" );
     ProjNode *proj = (ProjNode*)ctrl;
     if( proj->_con == TypeFunc::Control &&
         !C->node_arena()->contains(ctrl) ) // Unmatched old-space only
       break;
     i++;
   }
   Node *iff = NULL;
   for( DUIterator_Fast jmax, j = ctrl->fast_outs(jmax); j < jmax; j++ ) {
     Node *x = ctrl->fast_out(j);
     if( x->is_If() && x->req() > 1 &&
         !C->node_arena()->contains(x) ) { // Unmatched old-space only
       iff = x;
       break;
     }
   }
   if( !iff ) return false;
   Node *bol = iff->in(1);
   // The iff might be some random subclass of If or bol might be Con-Top
   if (!bol->is_Bool())  return false;
   assert( bol->req() > 1, "" );
   return (bol->in(1)->Opcode() == Op_FastUnlock);
 }
 // Used by the DFA in dfa_xxx.cpp.  Check for a following barrier or
 // atomic instruction acting as a store_load barrier without any
 // intervening volatile load, and thus we don't need a barrier here.
 // We retain the Node to act as a compiler ordering barrier.
 bool Matcher::post_store_load_barrier(const Node *vmb) {
   Compile *C = Compile::current();
   assert( vmb->is_MemBar(), "" );
   assert( vmb->Opcode() != Op_MemBarAcquire, "" );
   const MemBarNode *mem = (const MemBarNode*)vmb;
   // Get the Proj node, ctrl, that can be used to iterate forward
   Node *ctrl = NULL;
   DUIterator_Fast imax, i = mem->fast_outs(imax);
   while( true ) {
     ctrl = mem->fast_out(i);            // Throw out-of-bounds if proj not found
     assert( ctrl->is_Proj(), "only projections here" );
     ProjNode *proj = (ProjNode*)ctrl;
     if( proj->_con == TypeFunc::Control &&
         !C->node_arena()->contains(ctrl) ) // Unmatched old-space only
       break;
     i++;
   }
   for( DUIterator_Fast jmax, j = ctrl->fast_outs(jmax); j < jmax; j++ ) {
     Node *x = ctrl->fast_out(j);
     int xop = x->Opcode();
     // We don't need current barrier if we see another or a lock
     // before seeing volatile load.
     //
     // Op_Fastunlock previously appeared in the Op_* list below.
     // With the advent of 1-0 lock operations we're no longer guaranteed
     // that a monitor exit operation contains a serializing instruction.
     if (xop == Op_MemBarVolatile ||
         xop == Op_FastLock ||
         xop == Op_CompareAndSwapL ||
         xop == Op_CompareAndSwapP ||
         xop == Op_CompareAndSwapN ||
         xop == Op_CompareAndSwapI)
       return true;
     if (x->is_MemBar()) {
       // We must retain this membar if there is an upcoming volatile
       // load, which will be preceded by acquire membar.
       if (xop == Op_MemBarAcquire)
         return false;
       // For other kinds of barriers, check by pretending we
       // are them, and seeing if we can be removed.
       else
         return post_store_load_barrier((const MemBarNode*)x);
     }
     // Delicate code to detect case of an upcoming fastlock block
     if( x->is_If() && x->req() > 1 &&
         !C->node_arena()->contains(x) ) { // Unmatched old-space only
       Node *iff = x;
       Node *bol = iff->in(1);
       // The iff might be some random subclass of If or bol might be Con-Top
       if (!bol->is_Bool())  return false;
       assert( bol->req() > 1, "" );
       return (bol->in(1)->Opcode() == Op_FastUnlock);
     }
     // probably not necessary to check for these
     if (x->is_Call() || x->is_SafePoint() || x->is_block_proj())
       return false;
   }
   return false;
 }
 //=============================================================================
 //---------------------------State---------------------------------------------
 State::State(void) {
 #ifdef ASSERT
   _id = 0;
   _kids[0] = _kids[1] = (State*)(intptr_t) CONST64(0xcafebabecafebabe);
   _leaf = (Node*)(intptr_t) CONST64(0xbaadf00dbaadf00d);
   //memset(_cost, -1, sizeof(_cost));
   //memset(_rule, -1, sizeof(_rule));
 #endif
   memset(_valid, 0, sizeof(_valid));
 }
 #ifdef ASSERT
 State::~State() {
   _id = 99;
   _kids[0] = _kids[1] = (State*)(intptr_t) CONST64(0xcafebabecafebabe);
   _leaf = (Node*)(intptr_t) CONST64(0xbaadf00dbaadf00d);
   memset(_cost, -3, sizeof(_cost));
   memset(_rule, -3, sizeof(_rule));
 }
 #endif
 #ifndef PRODUCT
 //---------------------------dump----------------------------------------------
 void State::dump() {
   tty->print("\n");
   dump(0);
 }
 void State::dump(int depth) {
   for( int j = 0; j < depth; j++ )
     tty->print("   ");
   tty->print("--N: ");
   _leaf->dump();
   uint i;
   for( i = 0; i < _LAST_MACH_OPER; i++ )
     // Check for valid entry
     if( valid(i) ) {
       for( int j = 0; j < depth; j++ )
         tty->print("   ");
         assert(_cost[i] != max_juint, "cost must be a valid value");
         assert(_rule[i] < _last_Mach_Node, "rule[i] must be valid rule");
         tty->print_cr("%s  %d  %s",
                       ruleName[i], _cost[i], ruleName[_rule[i]] );
       }
   tty->print_cr("");
   for( i=0; i<2; i++ )
     if( _kids[i] )
       _kids[i]->dump(depth+1);
 }
 #endif

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/opto/matcher.cpp@97125851f396 (annotated)

src/share/vm/opto/matcher.cpp