1 /*
   2  * Copyright (c) 1998, 2024, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "asm/assembler.inline.hpp"
  27 #include "asm/macroAssembler.inline.hpp"
  28 #include "code/compiledIC.hpp"
  29 #include "code/debugInfo.hpp"
  30 #include "code/debugInfoRec.hpp"
  31 #include "compiler/compileBroker.hpp"
  32 #include "compiler/compilerDirectives.hpp"
  33 #include "compiler/disassembler.hpp"
  34 #include "compiler/oopMap.hpp"
  35 #include "gc/shared/barrierSet.hpp"
  36 #include "gc/shared/gc_globals.hpp"
  37 #include "gc/shared/c2/barrierSetC2.hpp"
  38 #include "memory/allocation.inline.hpp"
  39 #include "memory/allocation.hpp"
  40 #include "opto/ad.hpp"
  41 #include "opto/block.hpp"
  42 #include "opto/c2compiler.hpp"
  43 #include "opto/c2_MacroAssembler.hpp"
  44 #include "opto/callnode.hpp"
  45 #include "opto/cfgnode.hpp"
  46 #include "opto/locknode.hpp"
  47 #include "opto/machnode.hpp"
  48 #include "opto/node.hpp"
  49 #include "opto/optoreg.hpp"
  50 #include "opto/output.hpp"
  51 #include "opto/regalloc.hpp"
  52 #include "opto/runtime.hpp"
  53 #include "opto/subnode.hpp"
  54 #include "opto/type.hpp"
  55 #include "runtime/handles.inline.hpp"
  56 #include "runtime/sharedRuntime.hpp"
  57 #include "utilities/macros.hpp"
  58 #include "utilities/powerOfTwo.hpp"
  59 #include "utilities/xmlstream.hpp"
  60 
  61 #ifndef PRODUCT
  62 #define DEBUG_ARG(x) , x
  63 #else
  64 #define DEBUG_ARG(x)
  65 #endif
  66 
  67 //------------------------------Scheduling----------------------------------
  68 // This class contains all the information necessary to implement instruction
  69 // scheduling and bundling.
  70 class Scheduling {
  71 
  72 private:
  73   // Arena to use
  74   Arena *_arena;
  75 
  76   // Control-Flow Graph info
  77   PhaseCFG *_cfg;
  78 
  79   // Register Allocation info
  80   PhaseRegAlloc *_regalloc;
  81 
  82   // Number of nodes in the method
  83   uint _node_bundling_limit;
  84 
  85   // List of scheduled nodes. Generated in reverse order
  86   Node_List _scheduled;
  87 
  88   // List of nodes currently available for choosing for scheduling
  89   Node_List _available;
  90 
  91   // For each instruction beginning a bundle, the number of following
  92   // nodes to be bundled with it.
  93   Bundle *_node_bundling_base;
  94 
  95   // Mapping from register to Node
  96   Node_List _reg_node;
  97 
  98   // Free list for pinch nodes.
  99   Node_List _pinch_free_list;
 100 
 101   // Number of uses of this node within the containing basic block.
 102   short *_uses;
 103 
 104   // Schedulable portion of current block.  Skips Region/Phi/CreateEx up
 105   // front, branch+proj at end.  Also skips Catch/CProj (same as
 106   // branch-at-end), plus just-prior exception-throwing call.
 107   uint _bb_start, _bb_end;
 108 
 109   // Latency from the end of the basic block as scheduled
 110   unsigned short *_current_latency;
 111 
 112   // Remember the next node
 113   Node *_next_node;
 114 
 115   // Use this for an unconditional branch delay slot
 116   Node *_unconditional_delay_slot;
 117 
 118   // Pointer to a Nop
 119   MachNopNode *_nop;
 120 
 121   // Length of the current bundle, in instructions
 122   uint _bundle_instr_count;
 123 
 124   // Current Cycle number, for computing latencies and bundling
 125   uint _bundle_cycle_number;
 126 
 127   // Bundle information
 128   Pipeline_Use_Element _bundle_use_elements[resource_count];
 129   Pipeline_Use         _bundle_use;
 130 
 131   // Dump the available list
 132   void dump_available() const;
 133 
 134 public:
 135   Scheduling(Arena *arena, Compile &compile);
 136 
 137   // Destructor
 138   NOT_PRODUCT( ~Scheduling(); )
 139 
 140   // Step ahead "i" cycles
 141   void step(uint i);
 142 
 143   // Step ahead 1 cycle, and clear the bundle state (for example,
 144   // at a branch target)
 145   void step_and_clear();
 146 
 147   Bundle* node_bundling(const Node *n) {
 148     assert(valid_bundle_info(n), "oob");
 149     return (&_node_bundling_base[n->_idx]);
 150   }
 151 
 152   bool valid_bundle_info(const Node *n) const {
 153     return (_node_bundling_limit > n->_idx);
 154   }
 155 
 156   bool starts_bundle(const Node *n) const {
 157     return (_node_bundling_limit > n->_idx && _node_bundling_base[n->_idx].starts_bundle());
 158   }
 159 
 160   // Do the scheduling
 161   void DoScheduling();
 162 
 163   // Compute the register antidependencies within a basic block
 164   void ComputeRegisterAntidependencies(Block *bb);
 165   void verify_do_def( Node *n, OptoReg::Name def, const char *msg );
 166   void verify_good_schedule( Block *b, const char *msg );
 167   void anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def );
 168   void anti_do_use( Block *b, Node *use, OptoReg::Name use_reg );
 169 
 170   // Add a node to the current bundle
 171   void AddNodeToBundle(Node *n, const Block *bb);
 172 
 173   // Return an integer less than, equal to, or greater than zero
 174   // if the stack offset of the first argument is respectively
 175   // less than, equal to, or greater than the second.
 176   int compare_two_spill_nodes(Node* first, Node* second);
 177 
 178   // Add a node to the list of available nodes
 179   void AddNodeToAvailableList(Node *n);
 180 
 181   // Compute the local use count for the nodes in a block, and compute
 182   // the list of instructions with no uses in the block as available
 183   void ComputeUseCount(const Block *bb);
 184 
 185   // Choose an instruction from the available list to add to the bundle
 186   Node * ChooseNodeToBundle();
 187 
 188   // See if this Node fits into the currently accumulating bundle
 189   bool NodeFitsInBundle(Node *n);
 190 
 191   // Decrement the use count for a node
 192  void DecrementUseCounts(Node *n, const Block *bb);
 193 
 194   // Garbage collect pinch nodes for reuse by other blocks.
 195   void garbage_collect_pinch_nodes();
 196   // Clean up a pinch node for reuse (helper for above).
 197   void cleanup_pinch( Node *pinch );
 198 
 199   // Information for statistics gathering
 200 #ifndef PRODUCT
 201 private:
 202   // Gather information on size of nops relative to total
 203   uint _branches, _unconditional_delays;
 204 
 205   static uint _total_nop_size, _total_method_size;
 206   static uint _total_branches, _total_unconditional_delays;
 207   static uint _total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
 208 
 209 public:
 210   static void print_statistics();
 211 
 212   static void increment_instructions_per_bundle(uint i) {
 213     _total_instructions_per_bundle[i]++;
 214   }
 215 
 216   static void increment_nop_size(uint s) {
 217     _total_nop_size += s;
 218   }
 219 
 220   static void increment_method_size(uint s) {
 221     _total_method_size += s;
 222   }
 223 #endif
 224 
 225 };
 226 
 227 PhaseOutput::PhaseOutput()
 228   : Phase(Phase::Output),
 229     _code_buffer("Compile::Fill_buffer"),
 230     _first_block_size(0),
 231     _handler_table(),
 232     _inc_table(),
 233     _stub_list(),
 234     _oop_map_set(nullptr),
 235     _scratch_buffer_blob(nullptr),
 236     _scratch_locs_memory(nullptr),
 237     _scratch_const_size(-1),
 238     _in_scratch_emit_size(false),
 239     _frame_slots(0),
 240     _code_offsets(),
 241     _node_bundling_limit(0),
 242     _node_bundling_base(nullptr),
 243     _orig_pc_slot(0),
 244     _orig_pc_slot_offset_in_bytes(0),
 245     _buf_sizes(),
 246     _block(nullptr),
 247     _index(0) {
 248   C->set_output(this);
 249   if (C->stub_name() == nullptr) {
 250     int fixed_slots = C->fixed_slots();
 251     if (C->needs_stack_repair()) {
 252       fixed_slots -= 2;
 253     }
 254     // TODO 8284443 Only reserve extra slot if needed
 255     if (InlineTypeReturnedAsFields) {
 256       fixed_slots -= 2;
 257     }
 258     _orig_pc_slot = fixed_slots - (sizeof(address) / VMRegImpl::stack_slot_size);
 259   }
 260 }
 261 
 262 PhaseOutput::~PhaseOutput() {
 263   C->set_output(nullptr);
 264   if (_scratch_buffer_blob != nullptr) {
 265     BufferBlob::free(_scratch_buffer_blob);
 266   }
 267 }
 268 
 269 void PhaseOutput::perform_mach_node_analysis() {
 270   // Late barrier analysis must be done after schedule and bundle
 271   // Otherwise liveness based spilling will fail
 272   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
 273   bs->late_barrier_analysis();
 274 
 275   pd_perform_mach_node_analysis();
 276 
 277   C->print_method(CompilerPhaseType::PHASE_MACH_ANALYSIS, 3);
 278 }
 279 
 280 // Convert Nodes to instruction bits and pass off to the VM
 281 void PhaseOutput::Output() {
 282   // RootNode goes
 283   assert( C->cfg()->get_root_block()->number_of_nodes() == 0, "" );
 284 
 285   // The number of new nodes (mostly MachNop) is proportional to
 286   // the number of java calls and inner loops which are aligned.
 287   if ( C->check_node_count((NodeLimitFudgeFactor + C->java_calls()*3 +
 288                             C->inner_loops()*(OptoLoopAlignment-1)),
 289                            "out of nodes before code generation" ) ) {
 290     return;
 291   }
 292   // Make sure I can find the Start Node
 293   Block *entry = C->cfg()->get_block(1);
 294   Block *broot = C->cfg()->get_root_block();
 295 
 296   const StartNode *start = entry->head()->as_Start();
 297 
 298   // Replace StartNode with prolog
 299   Label verified_entry;
 300   MachPrologNode* prolog = new MachPrologNode(&verified_entry);
 301   entry->map_node(prolog, 0);
 302   C->cfg()->map_node_to_block(prolog, entry);
 303   C->cfg()->unmap_node_from_block(start); // start is no longer in any block
 304 
 305   // Virtual methods need an unverified entry point
 306   if (C->is_osr_compilation()) {
 307     if (PoisonOSREntry) {
 308       // TODO: Should use a ShouldNotReachHereNode...
 309       C->cfg()->insert( broot, 0, new MachBreakpointNode() );
 310     }
 311   } else {
 312     if (C->method()) {
 313       if (C->method()->has_scalarized_args()) {
 314         // Add entry point to unpack all inline type arguments
 315         C->cfg()->insert(broot, 0, new MachVEPNode(&verified_entry, /* verified */ true, /* receiver_only */ false));
 316         if (!C->method()->is_static()) {
 317           // Add verified/unverified entry points to only unpack inline type receiver at interface calls
 318           C->cfg()->insert(broot, 0, new MachVEPNode(&verified_entry, /* verified */ false, /* receiver_only */ false));
 319           C->cfg()->insert(broot, 0, new MachVEPNode(&verified_entry, /* verified */ true,  /* receiver_only */ true));
 320           C->cfg()->insert(broot, 0, new MachVEPNode(&verified_entry, /* verified */ false, /* receiver_only */ true));
 321         }
 322       } else if (!C->method()->is_static()) {
 323         // Insert unvalidated entry point
 324         C->cfg()->insert(broot, 0, new MachUEPNode());
 325       }
 326     }
 327   }
 328 
 329   // Break before main entry point
 330   if ((C->method() && C->directive()->BreakAtExecuteOption) ||
 331       (OptoBreakpoint && C->is_method_compilation())       ||
 332       (OptoBreakpointOSR && C->is_osr_compilation())       ||
 333       (OptoBreakpointC2R && !C->method())                   ) {
 334     // checking for C->method() means that OptoBreakpoint does not apply to
 335     // runtime stubs or frame converters
 336     C->cfg()->insert( entry, 1, new MachBreakpointNode() );
 337   }
 338 
 339   // Insert epilogs before every return
 340   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
 341     Block* block = C->cfg()->get_block(i);
 342     if (!block->is_connector() && block->non_connector_successor(0) == C->cfg()->get_root_block()) { // Found a program exit point?
 343       Node* m = block->end();
 344       if (m->is_Mach() && m->as_Mach()->ideal_Opcode() != Op_Halt) {
 345         MachEpilogNode* epilog = new MachEpilogNode(m->as_Mach()->ideal_Opcode() == Op_Return);
 346         block->add_inst(epilog);
 347         C->cfg()->map_node_to_block(epilog, block);
 348       }
 349     }
 350   }
 351 
 352   // Keeper of sizing aspects
 353   _buf_sizes = BufferSizingData();
 354 
 355   // Initialize code buffer
 356   estimate_buffer_size(_buf_sizes._const);
 357   if (C->failing()) return;
 358 
 359   // Pre-compute the length of blocks and replace
 360   // long branches with short if machine supports it.
 361   // Must be done before ScheduleAndBundle due to SPARC delay slots
 362   uint* blk_starts = NEW_RESOURCE_ARRAY(uint, C->cfg()->number_of_blocks() + 1);
 363   blk_starts[0] = 0;
 364   shorten_branches(blk_starts);
 365 
 366   if (!C->is_osr_compilation() && C->has_scalarized_args()) {
 367     // Compute the offsets of the entry points required by the inline type calling convention
 368     if (!C->method()->is_static()) {
 369       // We have entries at the beginning of the method, implemented by the first 4 nodes.
 370       // Entry                     (unverified) @ offset 0
 371       // Verified_Inline_Entry_RO
 372       // Inline_Entry              (unverified)
 373       // Verified_Inline_Entry
 374       uint offset = 0;
 375       _code_offsets.set_value(CodeOffsets::Entry, offset);
 376 
 377       offset += ((MachVEPNode*)broot->get_node(0))->size(C->regalloc());
 378       _code_offsets.set_value(CodeOffsets::Verified_Inline_Entry_RO, offset);
 379 
 380       offset += ((MachVEPNode*)broot->get_node(1))->size(C->regalloc());
 381       _code_offsets.set_value(CodeOffsets::Inline_Entry, offset);
 382 
 383       offset += ((MachVEPNode*)broot->get_node(2))->size(C->regalloc());
 384       _code_offsets.set_value(CodeOffsets::Verified_Inline_Entry, offset);
 385     } else {
 386       _code_offsets.set_value(CodeOffsets::Entry, -1); // will be patched later
 387       _code_offsets.set_value(CodeOffsets::Verified_Inline_Entry, 0);
 388     }
 389   }
 390 
 391   ScheduleAndBundle();
 392   if (C->failing()) {
 393     return;
 394   }
 395 
 396   perform_mach_node_analysis();
 397 
 398   // Complete sizing of codebuffer
 399   CodeBuffer* cb = init_buffer();
 400   if (cb == nullptr || C->failing()) {
 401     return;
 402   }
 403 
 404   BuildOopMaps();
 405 
 406   if (C->failing())  {
 407     return;
 408   }
 409 
 410   C2_MacroAssembler masm(cb);
 411   fill_buffer(&masm, blk_starts);
 412 }
 413 
 414 bool PhaseOutput::need_stack_bang(int frame_size_in_bytes) const {
 415   // Determine if we need to generate a stack overflow check.
 416   // Do it if the method is not a stub function and
 417   // has java calls or has frame size > vm_page_size/8.
 418   // The debug VM checks that deoptimization doesn't trigger an
 419   // unexpected stack overflow (compiled method stack banging should
 420   // guarantee it doesn't happen) so we always need the stack bang in
 421   // a debug VM.
 422   return (C->stub_function() == nullptr &&
 423           (C->has_java_calls() || frame_size_in_bytes > (int)(os::vm_page_size())>>3
 424            DEBUG_ONLY(|| true)));
 425 }
 426 
 427 bool PhaseOutput::need_register_stack_bang() const {
 428   // Determine if we need to generate a register stack overflow check.
 429   // This is only used on architectures which have split register
 430   // and memory stacks (ie. IA64).
 431   // Bang if the method is not a stub function and has java calls
 432   return (C->stub_function() == nullptr && C->has_java_calls());
 433 }
 434 
 435 
 436 // Compute the size of first NumberOfLoopInstrToAlign instructions at the top
 437 // of a loop. When aligning a loop we need to provide enough instructions
 438 // in cpu's fetch buffer to feed decoders. The loop alignment could be
 439 // avoided if we have enough instructions in fetch buffer at the head of a loop.
 440 // By default, the size is set to 999999 by Block's constructor so that
 441 // a loop will be aligned if the size is not reset here.
 442 //
 443 // Note: Mach instructions could contain several HW instructions
 444 // so the size is estimated only.
 445 //
 446 void PhaseOutput::compute_loop_first_inst_sizes() {
 447   // The next condition is used to gate the loop alignment optimization.
 448   // Don't aligned a loop if there are enough instructions at the head of a loop
 449   // or alignment padding is larger then MaxLoopPad. By default, MaxLoopPad
 450   // is equal to OptoLoopAlignment-1 except on new Intel cpus, where it is
 451   // equal to 11 bytes which is the largest address NOP instruction.
 452   if (MaxLoopPad < OptoLoopAlignment - 1) {
 453     uint last_block = C->cfg()->number_of_blocks() - 1;
 454     for (uint i = 1; i <= last_block; i++) {
 455       Block* block = C->cfg()->get_block(i);
 456       // Check the first loop's block which requires an alignment.
 457       if (block->loop_alignment() > (uint)relocInfo::addr_unit()) {
 458         uint sum_size = 0;
 459         uint inst_cnt = NumberOfLoopInstrToAlign;
 460         inst_cnt = block->compute_first_inst_size(sum_size, inst_cnt, C->regalloc());
 461 
 462         // Check subsequent fallthrough blocks if the loop's first
 463         // block(s) does not have enough instructions.
 464         Block *nb = block;
 465         while(inst_cnt > 0 &&
 466               i < last_block &&
 467               !C->cfg()->get_block(i + 1)->has_loop_alignment() &&
 468               !nb->has_successor(block)) {
 469           i++;
 470           nb = C->cfg()->get_block(i);
 471           inst_cnt  = nb->compute_first_inst_size(sum_size, inst_cnt, C->regalloc());
 472         } // while( inst_cnt > 0 && i < last_block  )
 473 
 474         block->set_first_inst_size(sum_size);
 475       } // f( b->head()->is_Loop() )
 476     } // for( i <= last_block )
 477   } // if( MaxLoopPad < OptoLoopAlignment-1 )
 478 }
 479 
 480 // The architecture description provides short branch variants for some long
 481 // branch instructions. Replace eligible long branches with short branches.
 482 void PhaseOutput::shorten_branches(uint* blk_starts) {
 483 
 484   Compile::TracePhase tp("shorten branches", &timers[_t_shortenBranches]);
 485 
 486   // Compute size of each block, method size, and relocation information size
 487   uint nblocks  = C->cfg()->number_of_blocks();
 488 
 489   uint*      jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
 490   uint*      jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
 491   int*       jmp_nidx   = NEW_RESOURCE_ARRAY(int ,nblocks);
 492 
 493   // Collect worst case block paddings
 494   int* block_worst_case_pad = NEW_RESOURCE_ARRAY(int, nblocks);
 495   memset(block_worst_case_pad, 0, nblocks * sizeof(int));
 496 
 497   DEBUG_ONLY( uint *jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks); )
 498   DEBUG_ONLY( uint *jmp_rule = NEW_RESOURCE_ARRAY(uint,nblocks); )
 499 
 500   bool has_short_branch_candidate = false;
 501 
 502   // Initialize the sizes to 0
 503   int code_size  = 0;          // Size in bytes of generated code
 504   int stub_size  = 0;          // Size in bytes of all stub entries
 505   // Size in bytes of all relocation entries, including those in local stubs.
 506   // Start with 2-bytes of reloc info for the unvalidated entry point
 507   int reloc_size = 1;          // Number of relocation entries
 508 
 509   // Make three passes.  The first computes pessimistic blk_starts,
 510   // relative jmp_offset and reloc_size information.  The second performs
 511   // short branch substitution using the pessimistic sizing.  The
 512   // third inserts nops where needed.
 513 
 514   // Step one, perform a pessimistic sizing pass.
 515   uint last_call_adr = max_juint;
 516   uint last_avoid_back_to_back_adr = max_juint;
 517   uint nop_size = (new MachNopNode())->size(C->regalloc());
 518   for (uint i = 0; i < nblocks; i++) { // For all blocks
 519     Block* block = C->cfg()->get_block(i);
 520     _block = block;
 521 
 522     // During short branch replacement, we store the relative (to blk_starts)
 523     // offset of jump in jmp_offset, rather than the absolute offset of jump.
 524     // This is so that we do not need to recompute sizes of all nodes when
 525     // we compute correct blk_starts in our next sizing pass.
 526     jmp_offset[i] = 0;
 527     jmp_size[i]   = 0;
 528     jmp_nidx[i]   = -1;
 529     DEBUG_ONLY( jmp_target[i] = 0; )
 530     DEBUG_ONLY( jmp_rule[i]   = 0; )
 531 
 532     // Sum all instruction sizes to compute block size
 533     uint last_inst = block->number_of_nodes();
 534     uint blk_size = 0;
 535     for (uint j = 0; j < last_inst; j++) {
 536       _index = j;
 537       Node* nj = block->get_node(_index);
 538       // Handle machine instruction nodes
 539       if (nj->is_Mach()) {
 540         MachNode* mach = nj->as_Mach();
 541         blk_size += (mach->alignment_required() - 1) * relocInfo::addr_unit(); // assume worst case padding
 542         reloc_size += mach->reloc();
 543         if (mach->is_MachCall()) {
 544           // add size information for trampoline stub
 545           // class CallStubImpl is platform-specific and defined in the *.ad files.
 546           stub_size  += CallStubImpl::size_call_trampoline();
 547           reloc_size += CallStubImpl::reloc_call_trampoline();
 548 
 549           MachCallNode *mcall = mach->as_MachCall();
 550           // This destination address is NOT PC-relative
 551 
 552           if (mcall->entry_point() != nullptr) {
 553             mcall->method_set((intptr_t)mcall->entry_point());
 554           }
 555 
 556           if (mcall->is_MachCallJava() && mcall->as_MachCallJava()->_method) {
 557             stub_size  += CompiledDirectCall::to_interp_stub_size();
 558             reloc_size += CompiledDirectCall::reloc_to_interp_stub();
 559           }
 560         } else if (mach->is_MachSafePoint()) {
 561           // If call/safepoint are adjacent, account for possible
 562           // nop to disambiguate the two safepoints.
 563           // ScheduleAndBundle() can rearrange nodes in a block,
 564           // check for all offsets inside this block.
 565           if (last_call_adr >= blk_starts[i]) {
 566             blk_size += nop_size;
 567           }
 568         }
 569         if (mach->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 570           // Nop is inserted between "avoid back to back" instructions.
 571           // ScheduleAndBundle() can rearrange nodes in a block,
 572           // check for all offsets inside this block.
 573           if (last_avoid_back_to_back_adr >= blk_starts[i]) {
 574             blk_size += nop_size;
 575           }
 576         }
 577         if (mach->may_be_short_branch()) {
 578           if (!nj->is_MachBranch()) {
 579 #ifndef PRODUCT
 580             nj->dump(3);
 581 #endif
 582             Unimplemented();
 583           }
 584           assert(jmp_nidx[i] == -1, "block should have only one branch");
 585           jmp_offset[i] = blk_size;
 586           jmp_size[i]   = nj->size(C->regalloc());
 587           jmp_nidx[i]   = j;
 588           has_short_branch_candidate = true;
 589         }
 590       }
 591       blk_size += nj->size(C->regalloc());
 592       // Remember end of call offset
 593       if (nj->is_MachCall() && !nj->is_MachCallLeaf()) {
 594         last_call_adr = blk_starts[i]+blk_size;
 595       }
 596       // Remember end of avoid_back_to_back offset
 597       if (nj->is_Mach() && nj->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
 598         last_avoid_back_to_back_adr = blk_starts[i]+blk_size;
 599       }
 600     }
 601 
 602     // When the next block starts a loop, we may insert pad NOP
 603     // instructions.  Since we cannot know our future alignment,
 604     // assume the worst.
 605     if (i < nblocks - 1) {
 606       Block* nb = C->cfg()->get_block(i + 1);
 607       int max_loop_pad = nb->code_alignment()-relocInfo::addr_unit();
 608       if (max_loop_pad > 0) {
 609         assert(is_power_of_2(max_loop_pad+relocInfo::addr_unit()), "");
 610         // Adjust last_call_adr and/or last_avoid_back_to_back_adr.
 611         // If either is the last instruction in this block, bump by
 612         // max_loop_pad in lock-step with blk_size, so sizing
 613         // calculations in subsequent blocks still can conservatively
 614         // detect that it may the last instruction in this block.
 615         if (last_call_adr == blk_starts[i]+blk_size) {
 616           last_call_adr += max_loop_pad;
 617         }
 618         if (last_avoid_back_to_back_adr == blk_starts[i]+blk_size) {
 619           last_avoid_back_to_back_adr += max_loop_pad;
 620         }
 621         blk_size += max_loop_pad;
 622         block_worst_case_pad[i + 1] = max_loop_pad;
 623       }
 624     }
 625 
 626     // Save block size; update total method size
 627     blk_starts[i+1] = blk_starts[i]+blk_size;
 628   }
 629 
 630   // Step two, replace eligible long jumps.
 631   bool progress = true;
 632   uint last_may_be_short_branch_adr = max_juint;
 633   while (has_short_branch_candidate && progress) {
 634     progress = false;
 635     has_short_branch_candidate = false;
 636     int adjust_block_start = 0;
 637     for (uint i = 0; i < nblocks; i++) {
 638       Block* block = C->cfg()->get_block(i);
 639       int idx = jmp_nidx[i];
 640       MachNode* mach = (idx == -1) ? nullptr: block->get_node(idx)->as_Mach();
 641       if (mach != nullptr && mach->may_be_short_branch()) {
 642 #ifdef ASSERT
 643         assert(jmp_size[i] > 0 && mach->is_MachBranch(), "sanity");
 644         int j;
 645         // Find the branch; ignore trailing NOPs.
 646         for (j = block->number_of_nodes()-1; j>=0; j--) {
 647           Node* n = block->get_node(j);
 648           if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con)
 649             break;
 650         }
 651         assert(j >= 0 && j == idx && block->get_node(j) == (Node*)mach, "sanity");
 652 #endif
 653         int br_size = jmp_size[i];
 654         int br_offs = blk_starts[i] + jmp_offset[i];
 655 
 656         // This requires the TRUE branch target be in succs[0]
 657         uint bnum = block->non_connector_successor(0)->_pre_order;
 658         int offset = blk_starts[bnum] - br_offs;
 659         if (bnum > i) { // adjust following block's offset
 660           offset -= adjust_block_start;
 661         }
 662 
 663         // This block can be a loop header, account for the padding
 664         // in the previous block.
 665         int block_padding = block_worst_case_pad[i];
 666         assert(i == 0 || block_padding == 0 || br_offs >= block_padding, "Should have at least a padding on top");
 667         // In the following code a nop could be inserted before
 668         // the branch which will increase the backward distance.
 669         bool needs_padding = ((uint)(br_offs - block_padding) == last_may_be_short_branch_adr);
 670         assert(!needs_padding || jmp_offset[i] == 0, "padding only branches at the beginning of block");
 671 
 672         if (needs_padding && offset <= 0)
 673           offset -= nop_size;
 674 
 675         if (C->matcher()->is_short_branch_offset(mach->rule(), br_size, offset)) {
 676           // We've got a winner.  Replace this branch.
 677           MachNode* replacement = mach->as_MachBranch()->short_branch_version();
 678 
 679           // Update the jmp_size.
 680           int new_size = replacement->size(C->regalloc());
 681           int diff     = br_size - new_size;
 682           assert(diff >= (int)nop_size, "short_branch size should be smaller");
 683           // Conservatively take into account padding between
 684           // avoid_back_to_back branches. Previous branch could be
 685           // converted into avoid_back_to_back branch during next
 686           // rounds.
 687           if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
 688             jmp_offset[i] += nop_size;
 689             diff -= nop_size;
 690           }
 691           adjust_block_start += diff;
 692           block->map_node(replacement, idx);
 693           mach->subsume_by(replacement, C);
 694           mach = replacement;
 695           progress = true;
 696 
 697           jmp_size[i] = new_size;
 698           DEBUG_ONLY( jmp_target[i] = bnum; );
 699           DEBUG_ONLY( jmp_rule[i] = mach->rule(); );
 700         } else {
 701           // The jump distance is not short, try again during next iteration.
 702           has_short_branch_candidate = true;
 703         }
 704       } // (mach->may_be_short_branch())
 705       if (mach != nullptr && (mach->may_be_short_branch() ||
 706                            mach->avoid_back_to_back(MachNode::AVOID_AFTER))) {
 707         last_may_be_short_branch_adr = blk_starts[i] + jmp_offset[i] + jmp_size[i];
 708       }
 709       blk_starts[i+1] -= adjust_block_start;
 710     }
 711   }
 712 
 713 #ifdef ASSERT
 714   for (uint i = 0; i < nblocks; i++) { // For all blocks
 715     if (jmp_target[i] != 0) {
 716       int br_size = jmp_size[i];
 717       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
 718       if (!C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
 719         tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
 720       }
 721       assert(C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset), "Displacement too large for short jmp");
 722     }
 723   }
 724 #endif
 725 
 726   // Step 3, compute the offsets of all blocks, will be done in fill_buffer()
 727   // after ScheduleAndBundle().
 728 
 729   // ------------------
 730   // Compute size for code buffer
 731   code_size = blk_starts[nblocks];
 732 
 733   // Relocation records
 734   reloc_size += 1;              // Relo entry for exception handler
 735 
 736   // Adjust reloc_size to number of record of relocation info
 737   // Min is 2 bytes, max is probably 6 or 8, with a tax up to 25% for
 738   // a relocation index.
 739   // The CodeBuffer will expand the locs array if this estimate is too low.
 740   reloc_size *= 10 / sizeof(relocInfo);
 741 
 742   _buf_sizes._reloc = reloc_size;
 743   _buf_sizes._code  = code_size;
 744   _buf_sizes._stub  = stub_size;
 745 }
 746 
 747 //------------------------------FillLocArray-----------------------------------
 748 // Create a bit of debug info and append it to the array.  The mapping is from
 749 // Java local or expression stack to constant, register or stack-slot.  For
 750 // doubles, insert 2 mappings and return 1 (to tell the caller that the next
 751 // entry has been taken care of and caller should skip it).
 752 static LocationValue *new_loc_value( PhaseRegAlloc *ra, OptoReg::Name regnum, Location::Type l_type ) {
 753   // This should never have accepted Bad before
 754   assert(OptoReg::is_valid(regnum), "location must be valid");
 755   return (OptoReg::is_reg(regnum))
 756          ? new LocationValue(Location::new_reg_loc(l_type, OptoReg::as_VMReg(regnum)) )
 757          : new LocationValue(Location::new_stk_loc(l_type,  ra->reg2offset(regnum)));
 758 }
 759 
 760 
 761 ObjectValue*
 762 PhaseOutput::sv_for_node_id(GrowableArray<ScopeValue*> *objs, int id) {
 763   for (int i = 0; i < objs->length(); i++) {
 764     assert(objs->at(i)->is_object(), "corrupt object cache");
 765     ObjectValue* sv = objs->at(i)->as_ObjectValue();
 766     if (sv->id() == id) {
 767       return sv;
 768     }
 769   }
 770   // Otherwise..
 771   return nullptr;
 772 }
 773 
 774 void PhaseOutput::set_sv_for_object_node(GrowableArray<ScopeValue*> *objs,
 775                                      ObjectValue* sv ) {
 776   assert(sv_for_node_id(objs, sv->id()) == nullptr, "Precondition");
 777   objs->append(sv);
 778 }
 779 
 780 
 781 void PhaseOutput::FillLocArray( int idx, MachSafePointNode* sfpt, Node *local,
 782                             GrowableArray<ScopeValue*> *array,
 783                             GrowableArray<ScopeValue*> *objs ) {
 784   assert( local, "use _top instead of null" );
 785   if (array->length() != idx) {
 786     assert(array->length() == idx + 1, "Unexpected array count");
 787     // Old functionality:
 788     //   return
 789     // New functionality:
 790     //   Assert if the local is not top. In product mode let the new node
 791     //   override the old entry.
 792     assert(local == C->top(), "LocArray collision");
 793     if (local == C->top()) {
 794       return;
 795     }
 796     array->pop();
 797   }
 798   const Type *t = local->bottom_type();
 799 
 800   // Is it a safepoint scalar object node?
 801   if (local->is_SafePointScalarObject()) {
 802     SafePointScalarObjectNode* spobj = local->as_SafePointScalarObject();
 803 
 804     ObjectValue* sv = sv_for_node_id(objs, spobj->_idx);
 805     if (sv == nullptr) {
 806       ciKlass* cik = t->is_oopptr()->exact_klass();
 807       assert(cik->is_instance_klass() ||
 808              cik->is_array_klass(), "Not supported allocation.");
 809       uint first_ind = spobj->first_index(sfpt->jvms());
 810       // Nullable, scalarized inline types have an is_init input
 811       // that needs to be checked before using the field values.
 812       ScopeValue* is_init = nullptr;
 813       if (cik->is_inlinetype()) {
 814         Node* init_node = sfpt->in(first_ind++);
 815         assert(init_node != nullptr, "is_init node not found");
 816         if (!init_node->is_top()) {
 817           const TypeInt* init_type = init_node->bottom_type()->is_int();
 818           if (init_node->is_Con()) {
 819             is_init = new ConstantIntValue(init_type->get_con());
 820           } else {
 821             OptoReg::Name init_reg = C->regalloc()->get_reg_first(init_node);
 822             is_init = new_loc_value(C->regalloc(), init_reg, Location::normal);
 823           }
 824         }
 825       }
 826       sv = new ObjectValue(spobj->_idx,
 827                            new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()), true, is_init);
 828       set_sv_for_object_node(objs, sv);
 829 
 830       for (uint i = 0; i < spobj->n_fields(); i++) {
 831         Node* fld_node = sfpt->in(first_ind+i);
 832         (void)FillLocArray(sv->field_values()->length(), sfpt, fld_node, sv->field_values(), objs);
 833       }
 834     }
 835     array->append(sv);
 836     return;
 837   } else if (local->is_SafePointScalarMerge()) {
 838     SafePointScalarMergeNode* smerge = local->as_SafePointScalarMerge();
 839     ObjectMergeValue* mv = (ObjectMergeValue*) sv_for_node_id(objs, smerge->_idx);
 840 
 841     if (mv == nullptr) {
 842       GrowableArray<ScopeValue*> deps;
 843 
 844       int merge_pointer_idx = smerge->merge_pointer_idx(sfpt->jvms());
 845       (void)FillLocArray(0, sfpt, sfpt->in(merge_pointer_idx), &deps, objs);
 846       assert(deps.length() == 1, "missing value");
 847 
 848       int selector_idx = smerge->selector_idx(sfpt->jvms());
 849       (void)FillLocArray(1, nullptr, sfpt->in(selector_idx), &deps, nullptr);
 850       assert(deps.length() == 2, "missing value");
 851 
 852       mv = new ObjectMergeValue(smerge->_idx, deps.at(0), deps.at(1));
 853       set_sv_for_object_node(objs, mv);
 854 
 855       for (uint i = 1; i < smerge->req(); i++) {
 856         Node* obj_node = smerge->in(i);
 857         (void)FillLocArray(mv->possible_objects()->length(), sfpt, obj_node, mv->possible_objects(), objs);
 858       }
 859     }
 860     array->append(mv);
 861     return;
 862   }
 863 
 864   // Grab the register number for the local
 865   OptoReg::Name regnum = C->regalloc()->get_reg_first(local);
 866   if( OptoReg::is_valid(regnum) ) {// Got a register/stack?
 867     // Record the double as two float registers.
 868     // The register mask for such a value always specifies two adjacent
 869     // float registers, with the lower register number even.
 870     // Normally, the allocation of high and low words to these registers
 871     // is irrelevant, because nearly all operations on register pairs
 872     // (e.g., StoreD) treat them as a single unit.
 873     // Here, we assume in addition that the words in these two registers
 874     // stored "naturally" (by operations like StoreD and double stores
 875     // within the interpreter) such that the lower-numbered register
 876     // is written to the lower memory address.  This may seem like
 877     // a machine dependency, but it is not--it is a requirement on
 878     // the author of the <arch>.ad file to ensure that, for every
 879     // even/odd double-register pair to which a double may be allocated,
 880     // the word in the even single-register is stored to the first
 881     // memory word.  (Note that register numbers are completely
 882     // arbitrary, and are not tied to any machine-level encodings.)
 883 #ifdef _LP64
 884     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon ) {
 885       array->append(new ConstantIntValue((jint)0));
 886       array->append(new_loc_value( C->regalloc(), regnum, Location::dbl ));
 887     } else if ( t->base() == Type::Long ) {
 888       array->append(new ConstantIntValue((jint)0));
 889       array->append(new_loc_value( C->regalloc(), regnum, Location::lng ));
 890     } else if ( t->base() == Type::RawPtr ) {
 891       // jsr/ret return address which must be restored into the full
 892       // width 64-bit stack slot.
 893       array->append(new_loc_value( C->regalloc(), regnum, Location::lng ));
 894     }
 895 #else //_LP64
 896     if( t->base() == Type::DoubleBot || t->base() == Type::DoubleCon || t->base() == Type::Long ) {
 897       // Repack the double/long as two jints.
 898       // The convention the interpreter uses is that the second local
 899       // holds the first raw word of the native double representation.
 900       // This is actually reasonable, since locals and stack arrays
 901       // grow downwards in all implementations.
 902       // (If, on some machine, the interpreter's Java locals or stack
 903       // were to grow upwards, the embedded doubles would be word-swapped.)
 904       array->append(new_loc_value( C->regalloc(), OptoReg::add(regnum,1), Location::normal ));
 905       array->append(new_loc_value( C->regalloc(),              regnum   , Location::normal ));
 906     }
 907 #endif //_LP64
 908     else if( (t->base() == Type::FloatBot || t->base() == Type::FloatCon) &&
 909              OptoReg::is_reg(regnum) ) {
 910       array->append(new_loc_value( C->regalloc(), regnum, Matcher::float_in_double()
 911                                                       ? Location::float_in_dbl : Location::normal ));
 912     } else if( t->base() == Type::Int && OptoReg::is_reg(regnum) ) {
 913       array->append(new_loc_value( C->regalloc(), regnum, Matcher::int_in_long
 914                                                       ? Location::int_in_long : Location::normal ));
 915     } else if( t->base() == Type::NarrowOop ) {
 916       array->append(new_loc_value( C->regalloc(), regnum, Location::narrowoop ));
 917     } else if (t->base() == Type::VectorA || t->base() == Type::VectorS ||
 918                t->base() == Type::VectorD || t->base() == Type::VectorX ||
 919                t->base() == Type::VectorY || t->base() == Type::VectorZ) {
 920       array->append(new_loc_value( C->regalloc(), regnum, Location::vector ));
 921     } else if (C->regalloc()->is_oop(local)) {
 922       assert(t->base() == Type::OopPtr || t->base() == Type::InstPtr ||
 923              t->base() == Type::AryPtr,
 924              "Unexpected type: %s", t->msg());
 925       array->append(new_loc_value( C->regalloc(), regnum, Location::oop ));
 926     } else {
 927       assert(t->base() == Type::Int || t->base() == Type::Half ||
 928              t->base() == Type::FloatCon || t->base() == Type::FloatBot,
 929              "Unexpected type: %s", t->msg());
 930       array->append(new_loc_value( C->regalloc(), regnum, Location::normal ));
 931     }
 932     return;
 933   }
 934 
 935   // No register.  It must be constant data.
 936   switch (t->base()) {
 937     case Type::Half:              // Second half of a double
 938       ShouldNotReachHere();       // Caller should skip 2nd halves
 939       break;
 940     case Type::AnyPtr:
 941       array->append(new ConstantOopWriteValue(nullptr));
 942       break;
 943     case Type::AryPtr:
 944     case Type::InstPtr:          // fall through
 945       array->append(new ConstantOopWriteValue(t->isa_oopptr()->const_oop()->constant_encoding()));
 946       break;
 947     case Type::NarrowOop:
 948       if (t == TypeNarrowOop::NULL_PTR) {
 949         array->append(new ConstantOopWriteValue(nullptr));
 950       } else {
 951         array->append(new ConstantOopWriteValue(t->make_ptr()->isa_oopptr()->const_oop()->constant_encoding()));
 952       }
 953       break;
 954     case Type::Int:
 955       array->append(new ConstantIntValue(t->is_int()->get_con()));
 956       break;
 957     case Type::RawPtr:
 958       // A return address (T_ADDRESS).
 959       assert((intptr_t)t->is_ptr()->get_con() < (intptr_t)0x10000, "must be a valid BCI");
 960 #ifdef _LP64
 961       // Must be restored to the full-width 64-bit stack slot.
 962       array->append(new ConstantLongValue(t->is_ptr()->get_con()));
 963 #else
 964       array->append(new ConstantIntValue(t->is_ptr()->get_con()));
 965 #endif
 966       break;
 967     case Type::FloatCon: {
 968       float f = t->is_float_constant()->getf();
 969       array->append(new ConstantIntValue(jint_cast(f)));
 970       break;
 971     }
 972     case Type::DoubleCon: {
 973       jdouble d = t->is_double_constant()->getd();
 974 #ifdef _LP64
 975       array->append(new ConstantIntValue((jint)0));
 976       array->append(new ConstantDoubleValue(d));
 977 #else
 978       // Repack the double as two jints.
 979     // The convention the interpreter uses is that the second local
 980     // holds the first raw word of the native double representation.
 981     // This is actually reasonable, since locals and stack arrays
 982     // grow downwards in all implementations.
 983     // (If, on some machine, the interpreter's Java locals or stack
 984     // were to grow upwards, the embedded doubles would be word-swapped.)
 985     jlong_accessor acc;
 986     acc.long_value = jlong_cast(d);
 987     array->append(new ConstantIntValue(acc.words[1]));
 988     array->append(new ConstantIntValue(acc.words[0]));
 989 #endif
 990       break;
 991     }
 992     case Type::Long: {
 993       jlong d = t->is_long()->get_con();
 994 #ifdef _LP64
 995       array->append(new ConstantIntValue((jint)0));
 996       array->append(new ConstantLongValue(d));
 997 #else
 998       // Repack the long as two jints.
 999     // The convention the interpreter uses is that the second local
1000     // holds the first raw word of the native double representation.
1001     // This is actually reasonable, since locals and stack arrays
1002     // grow downwards in all implementations.
1003     // (If, on some machine, the interpreter's Java locals or stack
1004     // were to grow upwards, the embedded doubles would be word-swapped.)
1005     jlong_accessor acc;
1006     acc.long_value = d;
1007     array->append(new ConstantIntValue(acc.words[1]));
1008     array->append(new ConstantIntValue(acc.words[0]));
1009 #endif
1010       break;
1011     }
1012     case Type::Top:               // Add an illegal value here
1013       array->append(new LocationValue(Location()));
1014       break;
1015     default:
1016       ShouldNotReachHere();
1017       break;
1018   }
1019 }
1020 
1021 // Determine if this node starts a bundle
1022 bool PhaseOutput::starts_bundle(const Node *n) const {
1023   return (_node_bundling_limit > n->_idx &&
1024           _node_bundling_base[n->_idx].starts_bundle());
1025 }
1026 
1027 // Determine if there is a monitor that has 'ov' as its owner.
1028 bool PhaseOutput::contains_as_owner(GrowableArray<MonitorValue*> *monarray, ObjectValue *ov) const {
1029   for (int k = 0; k < monarray->length(); k++) {
1030     MonitorValue* mv = monarray->at(k);
1031     if (mv->owner() == ov) {
1032       return true;
1033     }
1034   }
1035 
1036   return false;
1037 }
1038 
1039 // Determine if there is a scalar replaced object description represented by 'ov'.
1040 bool PhaseOutput::contains_as_scalarized_obj(JVMState* jvms, MachSafePointNode* sfn,
1041                                              GrowableArray<ScopeValue*>* objs,
1042                                              ObjectValue* ov) const {
1043   for (int i = 0; i < jvms->scl_size(); i++) {
1044     Node* n = sfn->scalarized_obj(jvms, i);
1045     // Other kinds of nodes that we may encounter here, for instance constants
1046     // representing values of fields of objects scalarized, aren't relevant for
1047     // us, since they don't map to ObjectValue.
1048     if (!n->is_SafePointScalarObject()) {
1049       continue;
1050     }
1051 
1052     ObjectValue* other = sv_for_node_id(objs, n->_idx);
1053     if (ov == other) {
1054       return true;
1055     }
1056   }
1057   return false;
1058 }
1059 
1060 //--------------------------Process_OopMap_Node--------------------------------
1061 void PhaseOutput::Process_OopMap_Node(MachNode *mach, int current_offset) {
1062   // Handle special safepoint nodes for synchronization
1063   MachSafePointNode *sfn   = mach->as_MachSafePoint();
1064   MachCallNode      *mcall;
1065 
1066   int safepoint_pc_offset = current_offset;
1067   bool is_method_handle_invoke = false;
1068   bool return_oop = false;
1069   bool return_scalarized = false;
1070   bool has_ea_local_in_scope = sfn->_has_ea_local_in_scope;
1071   bool arg_escape = false;
1072 
1073   // Add the safepoint in the DebugInfoRecorder
1074   if( !mach->is_MachCall() ) {
1075     mcall = nullptr;
1076     C->debug_info()->add_safepoint(safepoint_pc_offset, sfn->_oop_map);
1077   } else {
1078     mcall = mach->as_MachCall();
1079 
1080     // Is the call a MethodHandle call?
1081     if (mcall->is_MachCallJava()) {
1082       if (mcall->as_MachCallJava()->_method_handle_invoke) {
1083         assert(C->has_method_handle_invokes(), "must have been set during call generation");
1084         is_method_handle_invoke = true;
1085       }
1086       arg_escape = mcall->as_MachCallJava()->_arg_escape;
1087     }
1088 
1089     // Check if a call returns an object.
1090     if (mcall->returns_pointer() || mcall->returns_scalarized()) {
1091       return_oop = true;
1092     }
1093     if (mcall->returns_scalarized()) {
1094       return_scalarized = true;
1095     }
1096     safepoint_pc_offset += mcall->ret_addr_offset();
1097     C->debug_info()->add_safepoint(safepoint_pc_offset, mcall->_oop_map);
1098   }
1099 
1100   // Loop over the JVMState list to add scope information
1101   // Do not skip safepoints with a null method, they need monitor info
1102   JVMState* youngest_jvms = sfn->jvms();
1103   int max_depth = youngest_jvms->depth();
1104 
1105   // Allocate the object pool for scalar-replaced objects -- the map from
1106   // small-integer keys (which can be recorded in the local and ostack
1107   // arrays) to descriptions of the object state.
1108   GrowableArray<ScopeValue*> *objs = new GrowableArray<ScopeValue*>();
1109 
1110   // Visit scopes from oldest to youngest.
1111   for (int depth = 1; depth <= max_depth; depth++) {
1112     JVMState* jvms = youngest_jvms->of_depth(depth);
1113     int idx;
1114     ciMethod* method = jvms->has_method() ? jvms->method() : nullptr;
1115     // Safepoints that do not have method() set only provide oop-map and monitor info
1116     // to support GC; these do not support deoptimization.
1117     int num_locs = (method == nullptr) ? 0 : jvms->loc_size();
1118     int num_exps = (method == nullptr) ? 0 : jvms->stk_size();
1119     int num_mon  = jvms->nof_monitors();
1120     assert(method == nullptr || jvms->bci() < 0 || num_locs == method->max_locals(),
1121            "JVMS local count must match that of the method");
1122 
1123     // Add Local and Expression Stack Information
1124 
1125     // Insert locals into the locarray
1126     GrowableArray<ScopeValue*> *locarray = new GrowableArray<ScopeValue*>(num_locs);
1127     for( idx = 0; idx < num_locs; idx++ ) {
1128       FillLocArray( idx, sfn, sfn->local(jvms, idx), locarray, objs );
1129     }
1130 
1131     // Insert expression stack entries into the exparray
1132     GrowableArray<ScopeValue*> *exparray = new GrowableArray<ScopeValue*>(num_exps);
1133     for( idx = 0; idx < num_exps; idx++ ) {
1134       FillLocArray( idx,  sfn, sfn->stack(jvms, idx), exparray, objs );
1135     }
1136 
1137     // Add in mappings of the monitors
1138     assert( !method ||
1139             !method->is_synchronized() ||
1140             method->is_native() ||
1141             num_mon > 0 ||
1142             !GenerateSynchronizationCode,
1143             "monitors must always exist for synchronized methods");
1144 
1145     // Build the growable array of ScopeValues for exp stack
1146     GrowableArray<MonitorValue*> *monarray = new GrowableArray<MonitorValue*>(num_mon);
1147 
1148     // Loop over monitors and insert into array
1149     for (idx = 0; idx < num_mon; idx++) {
1150       // Grab the node that defines this monitor
1151       Node* box_node = sfn->monitor_box(jvms, idx);
1152       Node* obj_node = sfn->monitor_obj(jvms, idx);
1153 
1154       // Create ScopeValue for object
1155       ScopeValue *scval = nullptr;
1156 
1157       if (obj_node->is_SafePointScalarObject()) {
1158         SafePointScalarObjectNode* spobj = obj_node->as_SafePointScalarObject();
1159         scval = PhaseOutput::sv_for_node_id(objs, spobj->_idx);
1160         if (scval == nullptr) {
1161           const Type *t = spobj->bottom_type();
1162           ciKlass* cik = t->is_oopptr()->exact_klass();
1163           assert(cik->is_instance_klass() ||
1164                  cik->is_array_klass(), "Not supported allocation.");
1165           ObjectValue* sv = new ObjectValue(spobj->_idx,
1166                                             new ConstantOopWriteValue(cik->java_mirror()->constant_encoding()));
1167           PhaseOutput::set_sv_for_object_node(objs, sv);
1168 
1169           uint first_ind = spobj->first_index(youngest_jvms);
1170           for (uint i = 0; i < spobj->n_fields(); i++) {
1171             Node* fld_node = sfn->in(first_ind+i);
1172             (void)FillLocArray(sv->field_values()->length(), sfn, fld_node, sv->field_values(), objs);
1173           }
1174           scval = sv;
1175         }
1176       } else if (obj_node->is_SafePointScalarMerge()) {
1177         SafePointScalarMergeNode* smerge = obj_node->as_SafePointScalarMerge();
1178         ObjectMergeValue* mv = (ObjectMergeValue*) sv_for_node_id(objs, smerge->_idx);
1179 
1180         if (mv == nullptr) {
1181           GrowableArray<ScopeValue*> deps;
1182 
1183           int merge_pointer_idx = smerge->merge_pointer_idx(youngest_jvms);
1184           FillLocArray(0, sfn, sfn->in(merge_pointer_idx), &deps, objs);
1185           assert(deps.length() == 1, "missing value");
1186 
1187           int selector_idx = smerge->selector_idx(youngest_jvms);
1188           FillLocArray(1, nullptr, sfn->in(selector_idx), &deps, nullptr);
1189           assert(deps.length() == 2, "missing value");
1190 
1191           mv = new ObjectMergeValue(smerge->_idx, deps.at(0), deps.at(1));
1192           set_sv_for_object_node(objs, mv);
1193 
1194           for (uint i = 1; i < smerge->req(); i++) {
1195             Node* obj_node = smerge->in(i);
1196             FillLocArray(mv->possible_objects()->length(), sfn, obj_node, mv->possible_objects(), objs);
1197           }
1198         }
1199         scval = mv;
1200       } else if (!obj_node->is_Con()) {
1201         OptoReg::Name obj_reg = C->regalloc()->get_reg_first(obj_node);
1202         if( obj_node->bottom_type()->base() == Type::NarrowOop ) {
1203           scval = new_loc_value( C->regalloc(), obj_reg, Location::narrowoop );
1204         } else {
1205           scval = new_loc_value( C->regalloc(), obj_reg, Location::oop );
1206         }
1207       } else {
1208         const TypePtr *tp = obj_node->get_ptr_type();
1209         scval = new ConstantOopWriteValue(tp->is_oopptr()->const_oop()->constant_encoding());
1210       }
1211 
1212       OptoReg::Name box_reg = BoxLockNode::reg(box_node);
1213       Location basic_lock = Location::new_stk_loc(Location::normal,C->regalloc()->reg2offset(box_reg));
1214       bool eliminated = (box_node->is_BoxLock() && box_node->as_BoxLock()->is_eliminated());
1215       monarray->append(new MonitorValue(scval, basic_lock, eliminated));
1216     }
1217 
1218     // Mark ObjectValue nodes as root nodes if they are directly
1219     // referenced in the JVMS.
1220     for (int i = 0; i < objs->length(); i++) {
1221       ScopeValue* sv = objs->at(i);
1222       if (sv->is_object_merge()) {
1223         ObjectMergeValue* merge = sv->as_ObjectMergeValue();
1224 
1225         for (int j = 0; j< merge->possible_objects()->length(); j++) {
1226           ObjectValue* ov = merge->possible_objects()->at(j)->as_ObjectValue();
1227           bool is_root = locarray->contains(ov) ||
1228                          exparray->contains(ov) ||
1229                          contains_as_owner(monarray, ov) ||
1230                          contains_as_scalarized_obj(jvms, sfn, objs, ov);
1231           ov->set_root(is_root);
1232         }
1233       }
1234     }
1235 
1236     // We dump the object pool first, since deoptimization reads it in first.
1237     C->debug_info()->dump_object_pool(objs);
1238 
1239     // Build first class objects to pass to scope
1240     DebugToken *locvals = C->debug_info()->create_scope_values(locarray);
1241     DebugToken *expvals = C->debug_info()->create_scope_values(exparray);
1242     DebugToken *monvals = C->debug_info()->create_monitor_values(monarray);
1243 
1244     // Make method available for all Safepoints
1245     ciMethod* scope_method = method ? method : C->method();
1246     // Describe the scope here
1247     assert(jvms->bci() >= InvocationEntryBci && jvms->bci() <= 0x10000, "must be a valid or entry BCI");
1248     assert(!jvms->should_reexecute() || depth == max_depth, "reexecute allowed only for the youngest");
1249     // Now we can describe the scope.
1250     methodHandle null_mh;
1251     bool rethrow_exception = false;
1252     C->debug_info()->describe_scope(
1253       safepoint_pc_offset,
1254       null_mh,
1255       scope_method,
1256       jvms->bci(),
1257       jvms->should_reexecute(),
1258       rethrow_exception,
1259       is_method_handle_invoke,
1260       return_oop,
1261       return_scalarized,
1262       has_ea_local_in_scope,
1263       arg_escape,
1264       locvals,
1265       expvals,
1266       monvals
1267     );
1268   } // End jvms loop
1269 
1270   // Mark the end of the scope set.
1271   C->debug_info()->end_safepoint(safepoint_pc_offset);
1272 }
1273 
1274 
1275 
1276 // A simplified version of Process_OopMap_Node, to handle non-safepoints.
1277 class NonSafepointEmitter {
1278     Compile*  C;
1279     JVMState* _pending_jvms;
1280     int       _pending_offset;
1281 
1282     void emit_non_safepoint();
1283 
1284  public:
1285     NonSafepointEmitter(Compile* compile) {
1286       this->C = compile;
1287       _pending_jvms = nullptr;
1288       _pending_offset = 0;
1289     }
1290 
1291     void observe_instruction(Node* n, int pc_offset) {
1292       if (!C->debug_info()->recording_non_safepoints())  return;
1293 
1294       Node_Notes* nn = C->node_notes_at(n->_idx);
1295       if (nn == nullptr || nn->jvms() == nullptr)  return;
1296       if (_pending_jvms != nullptr &&
1297           _pending_jvms->same_calls_as(nn->jvms())) {
1298         // Repeated JVMS?  Stretch it up here.
1299         _pending_offset = pc_offset;
1300       } else {
1301         if (_pending_jvms != nullptr &&
1302             _pending_offset < pc_offset) {
1303           emit_non_safepoint();
1304         }
1305         _pending_jvms = nullptr;
1306         if (pc_offset > C->debug_info()->last_pc_offset()) {
1307           // This is the only way _pending_jvms can become non-null:
1308           _pending_jvms = nn->jvms();
1309           _pending_offset = pc_offset;
1310         }
1311       }
1312     }
1313 
1314     // Stay out of the way of real safepoints:
1315     void observe_safepoint(JVMState* jvms, int pc_offset) {
1316       if (_pending_jvms != nullptr &&
1317           !_pending_jvms->same_calls_as(jvms) &&
1318           _pending_offset < pc_offset) {
1319         emit_non_safepoint();
1320       }
1321       _pending_jvms = nullptr;
1322     }
1323 
1324     void flush_at_end() {
1325       if (_pending_jvms != nullptr) {
1326         emit_non_safepoint();
1327       }
1328       _pending_jvms = nullptr;
1329     }
1330 };
1331 
1332 void NonSafepointEmitter::emit_non_safepoint() {
1333   JVMState* youngest_jvms = _pending_jvms;
1334   int       pc_offset     = _pending_offset;
1335 
1336   // Clear it now:
1337   _pending_jvms = nullptr;
1338 
1339   DebugInformationRecorder* debug_info = C->debug_info();
1340   assert(debug_info->recording_non_safepoints(), "sanity");
1341 
1342   debug_info->add_non_safepoint(pc_offset);
1343   int max_depth = youngest_jvms->depth();
1344 
1345   // Visit scopes from oldest to youngest.
1346   for (int depth = 1; depth <= max_depth; depth++) {
1347     JVMState* jvms = youngest_jvms->of_depth(depth);
1348     ciMethod* method = jvms->has_method() ? jvms->method() : nullptr;
1349     assert(!jvms->should_reexecute() || depth==max_depth, "reexecute allowed only for the youngest");
1350     methodHandle null_mh;
1351     debug_info->describe_scope(pc_offset, null_mh, method, jvms->bci(), jvms->should_reexecute());
1352   }
1353 
1354   // Mark the end of the scope set.
1355   debug_info->end_non_safepoint(pc_offset);
1356 }
1357 
1358 //------------------------------init_buffer------------------------------------
1359 void PhaseOutput::estimate_buffer_size(int& const_req) {
1360 
1361   // Set the initially allocated size
1362   const_req = initial_const_capacity;
1363 
1364   // The extra spacing after the code is necessary on some platforms.
1365   // Sometimes we need to patch in a jump after the last instruction,
1366   // if the nmethod has been deoptimized.  (See 4932387, 4894843.)
1367 
1368   // Compute the byte offset where we can store the deopt pc.
1369   if (C->fixed_slots() != 0) {
1370     _orig_pc_slot_offset_in_bytes = C->regalloc()->reg2offset(OptoReg::stack2reg(_orig_pc_slot));
1371   }
1372 
1373   // Compute prolog code size
1374   _frame_slots = OptoReg::reg2stack(C->matcher()->_old_SP) + C->regalloc()->_framesize;
1375   assert(_frame_slots >= 0 && _frame_slots < 1000000, "sanity check");
1376 
1377   if (C->has_mach_constant_base_node()) {
1378     uint add_size = 0;
1379     // Fill the constant table.
1380     // Note:  This must happen before shorten_branches.
1381     for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
1382       Block* b = C->cfg()->get_block(i);
1383 
1384       for (uint j = 0; j < b->number_of_nodes(); j++) {
1385         Node* n = b->get_node(j);
1386 
1387         // If the node is a MachConstantNode evaluate the constant
1388         // value section.
1389         if (n->is_MachConstant()) {
1390           MachConstantNode* machcon = n->as_MachConstant();
1391           machcon->eval_constant(C);
1392         } else if (n->is_Mach()) {
1393           // On Power there are more nodes that issue constants.
1394           add_size += (n->as_Mach()->ins_num_consts() * 8);
1395         }
1396       }
1397     }
1398 
1399     // Calculate the offsets of the constants and the size of the
1400     // constant table (including the padding to the next section).
1401     constant_table().calculate_offsets_and_size();
1402     const_req = constant_table().size() + add_size;
1403   }
1404 
1405   // Initialize the space for the BufferBlob used to find and verify
1406   // instruction size in MachNode::emit_size()
1407   init_scratch_buffer_blob(const_req);
1408 }
1409 
1410 CodeBuffer* PhaseOutput::init_buffer() {
1411   int stub_req  = _buf_sizes._stub;
1412   int code_req  = _buf_sizes._code;
1413   int const_req = _buf_sizes._const;
1414 
1415   int pad_req   = NativeCall::byte_size();
1416 
1417   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1418   stub_req += bs->estimate_stub_size();
1419 
1420   // nmethod and CodeBuffer count stubs & constants as part of method's code.
1421   // class HandlerImpl is platform-specific and defined in the *.ad files.
1422   int exception_handler_req = HandlerImpl::size_exception_handler() + MAX_stubs_size; // add marginal slop for handler
1423   int deopt_handler_req     = HandlerImpl::size_deopt_handler()     + MAX_stubs_size; // add marginal slop for handler
1424   stub_req += MAX_stubs_size;   // ensure per-stub margin
1425   code_req += MAX_inst_size;    // ensure per-instruction margin
1426 
1427   if (StressCodeBuffers)
1428     code_req = const_req = stub_req = exception_handler_req = deopt_handler_req = 0x10;  // force expansion
1429 
1430   int total_req =
1431           const_req +
1432           code_req +
1433           pad_req +
1434           stub_req +
1435           exception_handler_req +
1436           deopt_handler_req;               // deopt handler
1437 
1438   if (C->has_method_handle_invokes())
1439     total_req += deopt_handler_req;  // deopt MH handler
1440 
1441   CodeBuffer* cb = code_buffer();
1442   cb->initialize(total_req, _buf_sizes._reloc);
1443 
1444   // Have we run out of code space?
1445   if ((cb->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1446     C->record_failure("CodeCache is full");
1447     return nullptr;
1448   }
1449   // Configure the code buffer.
1450   cb->initialize_consts_size(const_req);
1451   cb->initialize_stubs_size(stub_req);
1452   cb->initialize_oop_recorder(C->env()->oop_recorder());
1453 
1454   // fill in the nop array for bundling computations
1455   MachNode *_nop_list[Bundle::_nop_count];
1456   Bundle::initialize_nops(_nop_list);
1457 
1458   return cb;
1459 }
1460 
1461 //------------------------------fill_buffer------------------------------------
1462 void PhaseOutput::fill_buffer(C2_MacroAssembler* masm, uint* blk_starts) {
1463   // blk_starts[] contains offsets calculated during short branches processing,
1464   // offsets should not be increased during following steps.
1465 
1466   // Compute the size of first NumberOfLoopInstrToAlign instructions at head
1467   // of a loop. It is used to determine the padding for loop alignment.
1468   Compile::TracePhase tp("fill buffer", &timers[_t_fillBuffer]);
1469 
1470   compute_loop_first_inst_sizes();
1471 
1472   // Create oopmap set.
1473   _oop_map_set = new OopMapSet();
1474 
1475   // !!!!! This preserves old handling of oopmaps for now
1476   C->debug_info()->set_oopmaps(_oop_map_set);
1477 
1478   uint nblocks  = C->cfg()->number_of_blocks();
1479   // Count and start of implicit null check instructions
1480   uint inct_cnt = 0;
1481   uint* inct_starts = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1482 
1483   // Count and start of calls
1484   uint* call_returns = NEW_RESOURCE_ARRAY(uint, nblocks+1);
1485 
1486   uint  return_offset = 0;
1487   int nop_size = (new MachNopNode())->size(C->regalloc());
1488 
1489   int previous_offset = 0;
1490   int current_offset  = 0;
1491   int last_call_offset = -1;
1492   int last_avoid_back_to_back_offset = -1;
1493 #ifdef ASSERT
1494   uint* jmp_target = NEW_RESOURCE_ARRAY(uint,nblocks);
1495   uint* jmp_offset = NEW_RESOURCE_ARRAY(uint,nblocks);
1496   uint* jmp_size   = NEW_RESOURCE_ARRAY(uint,nblocks);
1497   uint* jmp_rule   = NEW_RESOURCE_ARRAY(uint,nblocks);
1498 #endif
1499 
1500   // Create an array of unused labels, one for each basic block, if printing is enabled
1501 #if defined(SUPPORT_OPTO_ASSEMBLY)
1502   int* node_offsets      = nullptr;
1503   uint node_offset_limit = C->unique();
1504 
1505   if (C->print_assembly()) {
1506     node_offsets = NEW_RESOURCE_ARRAY(int, node_offset_limit);
1507   }
1508   if (node_offsets != nullptr) {
1509     // We need to initialize. Unused array elements may contain garbage and mess up PrintOptoAssembly.
1510     memset(node_offsets, 0, node_offset_limit*sizeof(int));
1511   }
1512 #endif
1513 
1514   NonSafepointEmitter non_safepoints(C);  // emit non-safepoints lazily
1515 
1516   // Emit the constant table.
1517   if (C->has_mach_constant_base_node()) {
1518     if (!constant_table().emit(masm)) {
1519       C->record_failure("consts section overflow");
1520       return;
1521     }
1522   }
1523 
1524   // Create an array of labels, one for each basic block
1525   Label* blk_labels = NEW_RESOURCE_ARRAY(Label, nblocks+1);
1526   for (uint i = 0; i <= nblocks; i++) {
1527     blk_labels[i].init();
1528   }
1529 
1530   // Now fill in the code buffer
1531   Node* delay_slot = nullptr;
1532   for (uint i = 0; i < nblocks; i++) {
1533     Block* block = C->cfg()->get_block(i);
1534     _block = block;
1535     Node* head = block->head();
1536 
1537     // If this block needs to start aligned (i.e, can be reached other
1538     // than by falling-thru from the previous block), then force the
1539     // start of a new bundle.
1540     if (Pipeline::requires_bundling() && starts_bundle(head)) {
1541       masm->code()->flush_bundle(true);
1542     }
1543 
1544 #ifdef ASSERT
1545     if (!block->is_connector()) {
1546       stringStream st;
1547       block->dump_head(C->cfg(), &st);
1548       masm->block_comment(st.freeze());
1549     }
1550     jmp_target[i] = 0;
1551     jmp_offset[i] = 0;
1552     jmp_size[i]   = 0;
1553     jmp_rule[i]   = 0;
1554 #endif
1555     int blk_offset = current_offset;
1556 
1557     // Define the label at the beginning of the basic block
1558     masm->bind(blk_labels[block->_pre_order]);
1559 
1560     uint last_inst = block->number_of_nodes();
1561 
1562     // Emit block normally, except for last instruction.
1563     // Emit means "dump code bits into code buffer".
1564     for (uint j = 0; j<last_inst; j++) {
1565       _index = j;
1566 
1567       // Get the node
1568       Node* n = block->get_node(j);
1569 
1570       // See if delay slots are supported
1571       if (valid_bundle_info(n) && node_bundling(n)->used_in_unconditional_delay()) {
1572         assert(delay_slot == nullptr, "no use of delay slot node");
1573         assert(n->size(C->regalloc()) == Pipeline::instr_unit_size(), "delay slot instruction wrong size");
1574 
1575         delay_slot = n;
1576         continue;
1577       }
1578 
1579       // If this starts a new instruction group, then flush the current one
1580       // (but allow split bundles)
1581       if (Pipeline::requires_bundling() && starts_bundle(n))
1582         masm->code()->flush_bundle(false);
1583 
1584       // Special handling for SafePoint/Call Nodes
1585       bool is_mcall = false;
1586       if (n->is_Mach()) {
1587         MachNode *mach = n->as_Mach();
1588         is_mcall = n->is_MachCall();
1589         bool is_sfn = n->is_MachSafePoint();
1590 
1591         // If this requires all previous instructions be flushed, then do so
1592         if (is_sfn || is_mcall || mach->alignment_required() != 1) {
1593           masm->code()->flush_bundle(true);
1594           current_offset = masm->offset();
1595         }
1596 
1597         // A padding may be needed again since a previous instruction
1598         // could be moved to delay slot.
1599 
1600         // align the instruction if necessary
1601         int padding = mach->compute_padding(current_offset);
1602         // Make sure safepoint node for polling is distinct from a call's
1603         // return by adding a nop if needed.
1604         if (is_sfn && !is_mcall && padding == 0 && current_offset == last_call_offset) {
1605           padding = nop_size;
1606         }
1607         if (padding == 0 && mach->avoid_back_to_back(MachNode::AVOID_BEFORE) &&
1608             current_offset == last_avoid_back_to_back_offset) {
1609           // Avoid back to back some instructions.
1610           padding = nop_size;
1611         }
1612 
1613         if (padding > 0) {
1614           assert((padding % nop_size) == 0, "padding is not a multiple of NOP size");
1615           int nops_cnt = padding / nop_size;
1616           MachNode *nop = new MachNopNode(nops_cnt);
1617           block->insert_node(nop, j++);
1618           last_inst++;
1619           C->cfg()->map_node_to_block(nop, block);
1620           // Ensure enough space.
1621           masm->code()->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1622           if ((masm->code()->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1623             C->record_failure("CodeCache is full");
1624             return;
1625           }
1626           nop->emit(masm, C->regalloc());
1627           masm->code()->flush_bundle(true);
1628           current_offset = masm->offset();
1629         }
1630 
1631         bool observe_safepoint = is_sfn;
1632         // Remember the start of the last call in a basic block
1633         if (is_mcall) {
1634           MachCallNode *mcall = mach->as_MachCall();
1635 
1636           if (mcall->entry_point() != nullptr) {
1637             // This destination address is NOT PC-relative
1638             mcall->method_set((intptr_t)mcall->entry_point());
1639           }
1640 
1641           // Save the return address
1642           call_returns[block->_pre_order] = current_offset + mcall->ret_addr_offset();
1643 
1644           observe_safepoint = mcall->guaranteed_safepoint();
1645         }
1646 
1647         // sfn will be valid whenever mcall is valid now because of inheritance
1648         if (observe_safepoint) {
1649           // Handle special safepoint nodes for synchronization
1650           if (!is_mcall) {
1651             MachSafePointNode *sfn = mach->as_MachSafePoint();
1652             // !!!!! Stubs only need an oopmap right now, so bail out
1653             if (sfn->jvms()->method() == nullptr) {
1654               // Write the oopmap directly to the code blob??!!
1655               continue;
1656             }
1657           } // End synchronization
1658 
1659           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1660                                            current_offset);
1661           Process_OopMap_Node(mach, current_offset);
1662         } // End if safepoint
1663 
1664           // If this is a null check, then add the start of the previous instruction to the list
1665         else if( mach->is_MachNullCheck() ) {
1666           inct_starts[inct_cnt++] = previous_offset;
1667         }
1668 
1669           // If this is a branch, then fill in the label with the target BB's label
1670         else if (mach->is_MachBranch()) {
1671           // This requires the TRUE branch target be in succs[0]
1672           uint block_num = block->non_connector_successor(0)->_pre_order;
1673 
1674           // Try to replace long branch if delay slot is not used,
1675           // it is mostly for back branches since forward branch's
1676           // distance is not updated yet.
1677           bool delay_slot_is_used = valid_bundle_info(n) &&
1678                                     C->output()->node_bundling(n)->use_unconditional_delay();
1679           if (!delay_slot_is_used && mach->may_be_short_branch()) {
1680             assert(delay_slot == nullptr, "not expecting delay slot node");
1681             int br_size = n->size(C->regalloc());
1682             int offset = blk_starts[block_num] - current_offset;
1683             if (block_num >= i) {
1684               // Current and following block's offset are not
1685               // finalized yet, adjust distance by the difference
1686               // between calculated and final offsets of current block.
1687               offset -= (blk_starts[i] - blk_offset);
1688             }
1689             // In the following code a nop could be inserted before
1690             // the branch which will increase the backward distance.
1691             bool needs_padding = (current_offset == last_avoid_back_to_back_offset);
1692             if (needs_padding && offset <= 0)
1693               offset -= nop_size;
1694 
1695             if (C->matcher()->is_short_branch_offset(mach->rule(), br_size, offset)) {
1696               // We've got a winner.  Replace this branch.
1697               MachNode* replacement = mach->as_MachBranch()->short_branch_version();
1698 
1699               // Update the jmp_size.
1700               int new_size = replacement->size(C->regalloc());
1701               assert((br_size - new_size) >= (int)nop_size, "short_branch size should be smaller");
1702               // Insert padding between avoid_back_to_back branches.
1703               if (needs_padding && replacement->avoid_back_to_back(MachNode::AVOID_BEFORE)) {
1704                 MachNode *nop = new MachNopNode();
1705                 block->insert_node(nop, j++);
1706                 C->cfg()->map_node_to_block(nop, block);
1707                 last_inst++;
1708                 nop->emit(masm, C->regalloc());
1709                 masm->code()->flush_bundle(true);
1710                 current_offset = masm->offset();
1711               }
1712 #ifdef ASSERT
1713               jmp_target[i] = block_num;
1714               jmp_offset[i] = current_offset - blk_offset;
1715               jmp_size[i]   = new_size;
1716               jmp_rule[i]   = mach->rule();
1717 #endif
1718               block->map_node(replacement, j);
1719               mach->subsume_by(replacement, C);
1720               n    = replacement;
1721               mach = replacement;
1722             }
1723           }
1724           mach->as_MachBranch()->label_set( &blk_labels[block_num], block_num );
1725         } else if (mach->ideal_Opcode() == Op_Jump) {
1726           for (uint h = 0; h < block->_num_succs; h++) {
1727             Block* succs_block = block->_succs[h];
1728             for (uint j = 1; j < succs_block->num_preds(); j++) {
1729               Node* jpn = succs_block->pred(j);
1730               if (jpn->is_JumpProj() && jpn->in(0) == mach) {
1731                 uint block_num = succs_block->non_connector()->_pre_order;
1732                 Label *blkLabel = &blk_labels[block_num];
1733                 mach->add_case_label(jpn->as_JumpProj()->proj_no(), blkLabel);
1734               }
1735             }
1736           }
1737         } else if (!n->is_Proj()) {
1738           // Remember the beginning of the previous instruction, in case
1739           // it's followed by a flag-kill and a null-check.  Happens on
1740           // Intel all the time, with add-to-memory kind of opcodes.
1741           previous_offset = current_offset;
1742         }
1743 
1744         // Not an else-if!
1745         // If this is a trap based cmp then add its offset to the list.
1746         if (mach->is_TrapBasedCheckNode()) {
1747           inct_starts[inct_cnt++] = current_offset;
1748         }
1749       }
1750 
1751       // Verify that there is sufficient space remaining
1752       masm->code()->insts()->maybe_expand_to_ensure_remaining(MAX_inst_size);
1753       if ((masm->code()->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1754         C->record_failure("CodeCache is full");
1755         return;
1756       }
1757 
1758       // Save the offset for the listing
1759 #if defined(SUPPORT_OPTO_ASSEMBLY)
1760       if ((node_offsets != nullptr) && (n->_idx < node_offset_limit)) {
1761         node_offsets[n->_idx] = masm->offset();
1762       }
1763 #endif
1764       assert(!C->failing_internal() || C->failure_is_artificial(), "Should not reach here if failing.");
1765 
1766       // "Normal" instruction case
1767       DEBUG_ONLY(uint instr_offset = masm->offset());
1768       n->emit(masm, C->regalloc());
1769       current_offset = masm->offset();
1770 
1771       // Above we only verified that there is enough space in the instruction section.
1772       // However, the instruction may emit stubs that cause code buffer expansion.
1773       // Bail out here if expansion failed due to a lack of code cache space.
1774       if (C->failing()) {
1775         return;
1776       }
1777 
1778       assert(!is_mcall || (call_returns[block->_pre_order] <= (uint)current_offset),
1779              "ret_addr_offset() not within emitted code");
1780 #ifdef ASSERT
1781       uint n_size = n->size(C->regalloc());
1782       if (n_size < (current_offset-instr_offset)) {
1783         MachNode* mach = n->as_Mach();
1784         n->dump();
1785         mach->dump_format(C->regalloc(), tty);
1786         tty->print_cr(" n_size (%d), current_offset (%d), instr_offset (%d)", n_size, current_offset, instr_offset);
1787         Disassembler::decode(masm->code()->insts_begin() + instr_offset, masm->code()->insts_begin() + current_offset + 1, tty);
1788         tty->print_cr(" ------------------- ");
1789         BufferBlob* blob = this->scratch_buffer_blob();
1790         address blob_begin = blob->content_begin();
1791         Disassembler::decode(blob_begin, blob_begin + n_size + 1, tty);
1792         assert(false, "wrong size of mach node");
1793       }
1794 #endif
1795       non_safepoints.observe_instruction(n, current_offset);
1796 
1797       // mcall is last "call" that can be a safepoint
1798       // record it so we can see if a poll will directly follow it
1799       // in which case we'll need a pad to make the PcDesc sites unique
1800       // see  5010568. This can be slightly inaccurate but conservative
1801       // in the case that return address is not actually at current_offset.
1802       // This is a small price to pay.
1803 
1804       if (is_mcall) {
1805         last_call_offset = current_offset;
1806       }
1807 
1808       if (n->is_Mach() && n->as_Mach()->avoid_back_to_back(MachNode::AVOID_AFTER)) {
1809         // Avoid back to back some instructions.
1810         last_avoid_back_to_back_offset = current_offset;
1811       }
1812 
1813       // See if this instruction has a delay slot
1814       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
1815         guarantee(delay_slot != nullptr, "expecting delay slot node");
1816 
1817         // Back up 1 instruction
1818         masm->code()->set_insts_end(masm->code()->insts_end() - Pipeline::instr_unit_size());
1819 
1820         // Save the offset for the listing
1821 #if defined(SUPPORT_OPTO_ASSEMBLY)
1822         if ((node_offsets != nullptr) && (delay_slot->_idx < node_offset_limit)) {
1823           node_offsets[delay_slot->_idx] = masm->offset();
1824         }
1825 #endif
1826 
1827         // Support a SafePoint in the delay slot
1828         if (delay_slot->is_MachSafePoint()) {
1829           MachNode *mach = delay_slot->as_Mach();
1830           // !!!!! Stubs only need an oopmap right now, so bail out
1831           if (!mach->is_MachCall() && mach->as_MachSafePoint()->jvms()->method() == nullptr) {
1832             // Write the oopmap directly to the code blob??!!
1833             delay_slot = nullptr;
1834             continue;
1835           }
1836 
1837           int adjusted_offset = current_offset - Pipeline::instr_unit_size();
1838           non_safepoints.observe_safepoint(mach->as_MachSafePoint()->jvms(),
1839                                            adjusted_offset);
1840           // Generate an OopMap entry
1841           Process_OopMap_Node(mach, adjusted_offset);
1842         }
1843 
1844         // Insert the delay slot instruction
1845         delay_slot->emit(masm, C->regalloc());
1846 
1847         // Don't reuse it
1848         delay_slot = nullptr;
1849       }
1850 
1851     } // End for all instructions in block
1852 
1853     // If the next block is the top of a loop, pad this block out to align
1854     // the loop top a little. Helps prevent pipe stalls at loop back branches.
1855     if (i < nblocks-1) {
1856       Block *nb = C->cfg()->get_block(i + 1);
1857       int padding = nb->alignment_padding(current_offset);
1858       if( padding > 0 ) {
1859         MachNode *nop = new MachNopNode(padding / nop_size);
1860         block->insert_node(nop, block->number_of_nodes());
1861         C->cfg()->map_node_to_block(nop, block);
1862         nop->emit(masm, C->regalloc());
1863         current_offset = masm->offset();
1864       }
1865     }
1866     // Verify that the distance for generated before forward
1867     // short branches is still valid.
1868     guarantee((int)(blk_starts[i+1] - blk_starts[i]) >= (current_offset - blk_offset), "shouldn't increase block size");
1869 
1870     // Save new block start offset
1871     blk_starts[i] = blk_offset;
1872   } // End of for all blocks
1873   blk_starts[nblocks] = current_offset;
1874 
1875   non_safepoints.flush_at_end();
1876 
1877   // Offset too large?
1878   if (C->failing())  return;
1879 
1880   // Define a pseudo-label at the end of the code
1881   masm->bind( blk_labels[nblocks] );
1882 
1883   // Compute the size of the first block
1884   _first_block_size = blk_labels[1].loc_pos() - blk_labels[0].loc_pos();
1885 
1886 #ifdef ASSERT
1887   for (uint i = 0; i < nblocks; i++) { // For all blocks
1888     if (jmp_target[i] != 0) {
1889       int br_size = jmp_size[i];
1890       int offset = blk_starts[jmp_target[i]]-(blk_starts[i] + jmp_offset[i]);
1891       if (!C->matcher()->is_short_branch_offset(jmp_rule[i], br_size, offset)) {
1892         tty->print_cr("target (%d) - jmp_offset(%d) = offset (%d), jump_size(%d), jmp_block B%d, target_block B%d", blk_starts[jmp_target[i]], blk_starts[i] + jmp_offset[i], offset, br_size, i, jmp_target[i]);
1893         assert(false, "Displacement too large for short jmp");
1894       }
1895     }
1896   }
1897 #endif
1898 
1899   if (!masm->code()->finalize_stubs()) {
1900     C->record_failure("CodeCache is full");
1901     return;
1902   }
1903 
1904   BarrierSetC2* bs = BarrierSet::barrier_set()->barrier_set_c2();
1905   bs->emit_stubs(*masm->code());
1906   if (C->failing())  return;
1907 
1908   // Fill in stubs.
1909   assert(masm->inst_mark() == nullptr, "should be.");
1910   _stub_list.emit(*masm);
1911   if (C->failing())  return;
1912 
1913 #ifndef PRODUCT
1914   // Information on the size of the method, without the extraneous code
1915   Scheduling::increment_method_size(masm->offset());
1916 #endif
1917 
1918   // ------------------
1919   // Fill in exception table entries.
1920   FillExceptionTables(inct_cnt, call_returns, inct_starts, blk_labels);
1921 
1922   // Only java methods have exception handlers and deopt handlers
1923   // class HandlerImpl is platform-specific and defined in the *.ad files.
1924   if (C->method()) {
1925     // Emit the exception handler code.
1926     _code_offsets.set_value(CodeOffsets::Exceptions, HandlerImpl::emit_exception_handler(masm));
1927     if (C->failing()) {
1928       return; // CodeBuffer::expand failed
1929     }
1930     // Emit the deopt handler code.
1931     _code_offsets.set_value(CodeOffsets::Deopt, HandlerImpl::emit_deopt_handler(masm));
1932 
1933     // Emit the MethodHandle deopt handler code (if required).
1934     if (C->has_method_handle_invokes() && !C->failing()) {
1935       // We can use the same code as for the normal deopt handler, we
1936       // just need a different entry point address.
1937       _code_offsets.set_value(CodeOffsets::DeoptMH, HandlerImpl::emit_deopt_handler(masm));
1938     }
1939   }
1940 
1941   // One last check for failed CodeBuffer::expand:
1942   if ((masm->code()->blob() == nullptr) || (!CompileBroker::should_compile_new_jobs())) {
1943     C->record_failure("CodeCache is full");
1944     return;
1945   }
1946 
1947 #if defined(SUPPORT_ABSTRACT_ASSEMBLY) || defined(SUPPORT_ASSEMBLY) || defined(SUPPORT_OPTO_ASSEMBLY)
1948   if (C->print_assembly()) {
1949     tty->cr();
1950     tty->print_cr("============================= C2-compiled nmethod ==============================");
1951   }
1952 #endif
1953 
1954 #if defined(SUPPORT_OPTO_ASSEMBLY)
1955   // Dump the assembly code, including basic-block numbers
1956   if (C->print_assembly()) {
1957     ttyLocker ttyl;  // keep the following output all in one block
1958     if (!VMThread::should_terminate()) {  // test this under the tty lock
1959       // print_metadata and dump_asm may safepoint which makes us loose the ttylock.
1960       // We call them first and write to a stringStream, then we retake the lock to
1961       // make sure the end tag is coherent, and that xmlStream->pop_tag is done thread safe.
1962       ResourceMark rm;
1963       stringStream method_metadata_str;
1964       if (C->method() != nullptr) {
1965         C->method()->print_metadata(&method_metadata_str);
1966       }
1967       stringStream dump_asm_str;
1968       dump_asm_on(&dump_asm_str, node_offsets, node_offset_limit);
1969 
1970       NoSafepointVerifier nsv;
1971       ttyLocker ttyl2;
1972       // This output goes directly to the tty, not the compiler log.
1973       // To enable tools to match it up with the compilation activity,
1974       // be sure to tag this tty output with the compile ID.
1975       if (xtty != nullptr) {
1976         xtty->head("opto_assembly compile_id='%d'%s", C->compile_id(),
1977                    C->is_osr_compilation() ? " compile_kind='osr'" : "");
1978       }
1979       if (C->method() != nullptr) {
1980         tty->print_cr("----------------------- MetaData before Compile_id = %d ------------------------", C->compile_id());
1981         tty->print_raw(method_metadata_str.freeze());
1982       } else if (C->stub_name() != nullptr) {
1983         tty->print_cr("----------------------------- RuntimeStub %s -------------------------------", C->stub_name());
1984       }
1985       tty->cr();
1986       tty->print_cr("------------------------ OptoAssembly for Compile_id = %d -----------------------", C->compile_id());
1987       tty->print_raw(dump_asm_str.freeze());
1988       tty->print_cr("--------------------------------------------------------------------------------");
1989       if (xtty != nullptr) {
1990         xtty->tail("opto_assembly");
1991       }
1992     }
1993   }
1994 #endif
1995 }
1996 
1997 void PhaseOutput::FillExceptionTables(uint cnt, uint *call_returns, uint *inct_starts, Label *blk_labels) {
1998   _inc_table.set_size(cnt);
1999 
2000   uint inct_cnt = 0;
2001   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
2002     Block* block = C->cfg()->get_block(i);
2003     Node *n = nullptr;
2004     int j;
2005 
2006     // Find the branch; ignore trailing NOPs.
2007     for (j = block->number_of_nodes() - 1; j >= 0; j--) {
2008       n = block->get_node(j);
2009       if (!n->is_Mach() || n->as_Mach()->ideal_Opcode() != Op_Con) {
2010         break;
2011       }
2012     }
2013 
2014     // If we didn't find anything, continue
2015     if (j < 0) {
2016       continue;
2017     }
2018 
2019     // Compute ExceptionHandlerTable subtable entry and add it
2020     // (skip empty blocks)
2021     if (n->is_Catch()) {
2022 
2023       // Get the offset of the return from the call
2024       uint call_return = call_returns[block->_pre_order];
2025 #ifdef ASSERT
2026       assert( call_return > 0, "no call seen for this basic block" );
2027       while (block->get_node(--j)->is_MachProj()) ;
2028       assert(block->get_node(j)->is_MachCall(), "CatchProj must follow call");
2029 #endif
2030       // last instruction is a CatchNode, find it's CatchProjNodes
2031       int nof_succs = block->_num_succs;
2032       // allocate space
2033       GrowableArray<intptr_t> handler_bcis(nof_succs);
2034       GrowableArray<intptr_t> handler_pcos(nof_succs);
2035       // iterate through all successors
2036       for (int j = 0; j < nof_succs; j++) {
2037         Block* s = block->_succs[j];
2038         bool found_p = false;
2039         for (uint k = 1; k < s->num_preds(); k++) {
2040           Node* pk = s->pred(k);
2041           if (pk->is_CatchProj() && pk->in(0) == n) {
2042             const CatchProjNode* p = pk->as_CatchProj();
2043             found_p = true;
2044             // add the corresponding handler bci & pco information
2045             if (p->_con != CatchProjNode::fall_through_index) {
2046               // p leads to an exception handler (and is not fall through)
2047               assert(s == C->cfg()->get_block(s->_pre_order), "bad numbering");
2048               // no duplicates, please
2049               if (!handler_bcis.contains(p->handler_bci())) {
2050                 uint block_num = s->non_connector()->_pre_order;
2051                 handler_bcis.append(p->handler_bci());
2052                 handler_pcos.append(blk_labels[block_num].loc_pos());
2053               }
2054             }
2055           }
2056         }
2057         assert(found_p, "no matching predecessor found");
2058         // Note:  Due to empty block removal, one block may have
2059         // several CatchProj inputs, from the same Catch.
2060       }
2061 
2062       // Set the offset of the return from the call
2063       assert(handler_bcis.find(-1) != -1, "must have default handler");
2064       _handler_table.add_subtable(call_return, &handler_bcis, nullptr, &handler_pcos);
2065       continue;
2066     }
2067 
2068     // Handle implicit null exception table updates
2069     if (n->is_MachNullCheck()) {
2070       assert(n->in(1)->as_Mach()->barrier_data() == 0,
2071              "Implicit null checks on memory accesses with barriers are not yet supported");
2072       uint block_num = block->non_connector_successor(0)->_pre_order;
2073       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
2074       continue;
2075     }
2076     // Handle implicit exception table updates: trap instructions.
2077     if (n->is_Mach() && n->as_Mach()->is_TrapBasedCheckNode()) {
2078       uint block_num = block->non_connector_successor(0)->_pre_order;
2079       _inc_table.append(inct_starts[inct_cnt++], blk_labels[block_num].loc_pos());
2080       continue;
2081     }
2082   } // End of for all blocks fill in exception table entries
2083 }
2084 
2085 // Static Variables
2086 #ifndef PRODUCT
2087 uint Scheduling::_total_nop_size = 0;
2088 uint Scheduling::_total_method_size = 0;
2089 uint Scheduling::_total_branches = 0;
2090 uint Scheduling::_total_unconditional_delays = 0;
2091 uint Scheduling::_total_instructions_per_bundle[Pipeline::_max_instrs_per_cycle+1];
2092 #endif
2093 
2094 // Initializer for class Scheduling
2095 
2096 Scheduling::Scheduling(Arena *arena, Compile &compile)
2097         : _arena(arena),
2098           _cfg(compile.cfg()),
2099           _regalloc(compile.regalloc()),
2100           _scheduled(arena),
2101           _available(arena),
2102           _reg_node(arena),
2103           _pinch_free_list(arena),
2104           _next_node(nullptr),
2105           _bundle_instr_count(0),
2106           _bundle_cycle_number(0),
2107           _bundle_use(0, 0, resource_count, &_bundle_use_elements[0])
2108 #ifndef PRODUCT
2109         , _branches(0)
2110         , _unconditional_delays(0)
2111 #endif
2112 {
2113   // Create a MachNopNode
2114   _nop = new MachNopNode();
2115 
2116   // Now that the nops are in the array, save the count
2117   // (but allow entries for the nops)
2118   _node_bundling_limit = compile.unique();
2119   uint node_max = _regalloc->node_regs_max_index();
2120 
2121   compile.output()->set_node_bundling_limit(_node_bundling_limit);
2122 
2123   // This one is persistent within the Compile class
2124   _node_bundling_base = NEW_ARENA_ARRAY(compile.comp_arena(), Bundle, node_max);
2125 
2126   // Allocate space for fixed-size arrays
2127   _uses            = NEW_ARENA_ARRAY(arena, short,          node_max);
2128   _current_latency = NEW_ARENA_ARRAY(arena, unsigned short, node_max);
2129 
2130   // Clear the arrays
2131   for (uint i = 0; i < node_max; i++) {
2132     ::new (&_node_bundling_base[i]) Bundle();
2133   }
2134   memset(_uses,               0, node_max * sizeof(short));
2135   memset(_current_latency,    0, node_max * sizeof(unsigned short));
2136 
2137   // Clear the bundling information
2138   memcpy(_bundle_use_elements, Pipeline_Use::elaborated_elements, sizeof(Pipeline_Use::elaborated_elements));
2139 
2140   // Get the last node
2141   Block* block = _cfg->get_block(_cfg->number_of_blocks() - 1);
2142 
2143   _next_node = block->get_node(block->number_of_nodes() - 1);
2144 }
2145 
2146 #ifndef PRODUCT
2147 // Scheduling destructor
2148 Scheduling::~Scheduling() {
2149   _total_branches             += _branches;
2150   _total_unconditional_delays += _unconditional_delays;
2151 }
2152 #endif
2153 
2154 // Step ahead "i" cycles
2155 void Scheduling::step(uint i) {
2156 
2157   Bundle *bundle = node_bundling(_next_node);
2158   bundle->set_starts_bundle();
2159 
2160   // Update the bundle record, but leave the flags information alone
2161   if (_bundle_instr_count > 0) {
2162     bundle->set_instr_count(_bundle_instr_count);
2163     bundle->set_resources_used(_bundle_use.resourcesUsed());
2164   }
2165 
2166   // Update the state information
2167   _bundle_instr_count = 0;
2168   _bundle_cycle_number += i;
2169   _bundle_use.step(i);
2170 }
2171 
2172 void Scheduling::step_and_clear() {
2173   Bundle *bundle = node_bundling(_next_node);
2174   bundle->set_starts_bundle();
2175 
2176   // Update the bundle record
2177   if (_bundle_instr_count > 0) {
2178     bundle->set_instr_count(_bundle_instr_count);
2179     bundle->set_resources_used(_bundle_use.resourcesUsed());
2180 
2181     _bundle_cycle_number += 1;
2182   }
2183 
2184   // Clear the bundling information
2185   _bundle_instr_count = 0;
2186   _bundle_use.reset();
2187 
2188   memcpy(_bundle_use_elements,
2189          Pipeline_Use::elaborated_elements,
2190          sizeof(Pipeline_Use::elaborated_elements));
2191 }
2192 
2193 // Perform instruction scheduling and bundling over the sequence of
2194 // instructions in backwards order.
2195 void PhaseOutput::ScheduleAndBundle() {
2196 
2197   // Don't optimize this if it isn't a method
2198   if (!C->method())
2199     return;
2200 
2201   // Don't optimize this if scheduling is disabled
2202   if (!C->do_scheduling())
2203     return;
2204 
2205   // Scheduling code works only with pairs (8 bytes) maximum.
2206   // And when the scalable vector register is used, we may spill/unspill
2207   // the whole reg regardless of the max vector size.
2208   if (C->max_vector_size() > 8 ||
2209       (C->max_vector_size() > 0 && Matcher::supports_scalable_vector())) {
2210     return;
2211   }
2212 
2213   Compile::TracePhase tp("isched", &timers[_t_instrSched]);
2214 
2215   // Create a data structure for all the scheduling information
2216   Scheduling scheduling(Thread::current()->resource_area(), *C);
2217 
2218   // Walk backwards over each basic block, computing the needed alignment
2219   // Walk over all the basic blocks
2220   scheduling.DoScheduling();
2221 
2222 #ifndef PRODUCT
2223   if (C->trace_opto_output()) {
2224     // Buffer and print all at once
2225     ResourceMark rm;
2226     stringStream ss;
2227     ss.print("\n---- After ScheduleAndBundle ----\n");
2228     print_scheduling(&ss);
2229     tty->print("%s", ss.as_string());
2230   }
2231 #endif
2232 }
2233 
2234 #ifndef PRODUCT
2235 // Separated out so that it can be called directly from debugger
2236 void PhaseOutput::print_scheduling() {
2237   print_scheduling(tty);
2238 }
2239 
2240 void PhaseOutput::print_scheduling(outputStream* output_stream) {
2241   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
2242     output_stream->print("\nBB#%03d:\n", i);
2243     Block* block = C->cfg()->get_block(i);
2244     for (uint j = 0; j < block->number_of_nodes(); j++) {
2245       Node* n = block->get_node(j);
2246       OptoReg::Name reg = C->regalloc()->get_reg_first(n);
2247       output_stream->print(" %-6s ", reg >= 0 && reg < REG_COUNT ? Matcher::regName[reg] : "");
2248       n->dump("\n", false, output_stream);
2249     }
2250   }
2251 }
2252 #endif
2253 
2254 // See if this node fits into the present instruction bundle
2255 bool Scheduling::NodeFitsInBundle(Node *n) {
2256   uint n_idx = n->_idx;
2257 
2258   // If this is the unconditional delay instruction, then it fits
2259   if (n == _unconditional_delay_slot) {
2260 #ifndef PRODUCT
2261     if (_cfg->C->trace_opto_output())
2262       tty->print("#     NodeFitsInBundle [%4d]: TRUE; is in unconditional delay slot\n", n->_idx);
2263 #endif
2264     return (true);
2265   }
2266 
2267   // If the node cannot be scheduled this cycle, skip it
2268   if (_current_latency[n_idx] > _bundle_cycle_number) {
2269 #ifndef PRODUCT
2270     if (_cfg->C->trace_opto_output())
2271       tty->print("#     NodeFitsInBundle [%4d]: FALSE; latency %4d > %d\n",
2272                  n->_idx, _current_latency[n_idx], _bundle_cycle_number);
2273 #endif
2274     return (false);
2275   }
2276 
2277   const Pipeline *node_pipeline = n->pipeline();
2278 
2279   uint instruction_count = node_pipeline->instructionCount();
2280   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2281     instruction_count = 0;
2282   else if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2283     instruction_count++;
2284 
2285   if (_bundle_instr_count + instruction_count > Pipeline::_max_instrs_per_cycle) {
2286 #ifndef PRODUCT
2287     if (_cfg->C->trace_opto_output())
2288       tty->print("#     NodeFitsInBundle [%4d]: FALSE; too many instructions: %d > %d\n",
2289                  n->_idx, _bundle_instr_count + instruction_count, Pipeline::_max_instrs_per_cycle);
2290 #endif
2291     return (false);
2292   }
2293 
2294   // Don't allow non-machine nodes to be handled this way
2295   if (!n->is_Mach() && instruction_count == 0)
2296     return (false);
2297 
2298   // See if there is any overlap
2299   uint delay = _bundle_use.full_latency(0, node_pipeline->resourceUse());
2300 
2301   if (delay > 0) {
2302 #ifndef PRODUCT
2303     if (_cfg->C->trace_opto_output())
2304       tty->print("#     NodeFitsInBundle [%4d]: FALSE; functional units overlap\n", n_idx);
2305 #endif
2306     return false;
2307   }
2308 
2309 #ifndef PRODUCT
2310   if (_cfg->C->trace_opto_output())
2311     tty->print("#     NodeFitsInBundle [%4d]:  TRUE\n", n_idx);
2312 #endif
2313 
2314   return true;
2315 }
2316 
2317 Node * Scheduling::ChooseNodeToBundle() {
2318   uint siz = _available.size();
2319 
2320   if (siz == 0) {
2321 
2322 #ifndef PRODUCT
2323     if (_cfg->C->trace_opto_output())
2324       tty->print("#   ChooseNodeToBundle: null\n");
2325 #endif
2326     return (nullptr);
2327   }
2328 
2329   // Fast path, if only 1 instruction in the bundle
2330   if (siz == 1) {
2331 #ifndef PRODUCT
2332     if (_cfg->C->trace_opto_output()) {
2333       tty->print("#   ChooseNodeToBundle (only 1): ");
2334       _available[0]->dump();
2335     }
2336 #endif
2337     return (_available[0]);
2338   }
2339 
2340   // Don't bother, if the bundle is already full
2341   if (_bundle_instr_count < Pipeline::_max_instrs_per_cycle) {
2342     for ( uint i = 0; i < siz; i++ ) {
2343       Node *n = _available[i];
2344 
2345       // Skip projections, we'll handle them another way
2346       if (n->is_Proj())
2347         continue;
2348 
2349       // This presupposed that instructions are inserted into the
2350       // available list in a legality order; i.e. instructions that
2351       // must be inserted first are at the head of the list
2352       if (NodeFitsInBundle(n)) {
2353 #ifndef PRODUCT
2354         if (_cfg->C->trace_opto_output()) {
2355           tty->print("#   ChooseNodeToBundle: ");
2356           n->dump();
2357         }
2358 #endif
2359         return (n);
2360       }
2361     }
2362   }
2363 
2364   // Nothing fits in this bundle, choose the highest priority
2365 #ifndef PRODUCT
2366   if (_cfg->C->trace_opto_output()) {
2367     tty->print("#   ChooseNodeToBundle: ");
2368     _available[0]->dump();
2369   }
2370 #endif
2371 
2372   return _available[0];
2373 }
2374 
2375 int Scheduling::compare_two_spill_nodes(Node* first, Node* second) {
2376   assert(first->is_MachSpillCopy() && second->is_MachSpillCopy(), "");
2377 
2378   OptoReg::Name first_src_lo = _regalloc->get_reg_first(first->in(1));
2379   OptoReg::Name first_dst_lo = _regalloc->get_reg_first(first);
2380   OptoReg::Name second_src_lo = _regalloc->get_reg_first(second->in(1));
2381   OptoReg::Name second_dst_lo = _regalloc->get_reg_first(second);
2382 
2383   // Comparison between stack -> reg and stack -> reg
2384   if (OptoReg::is_stack(first_src_lo) && OptoReg::is_stack(second_src_lo) &&
2385       OptoReg::is_reg(first_dst_lo) && OptoReg::is_reg(second_dst_lo)) {
2386     return _regalloc->reg2offset(first_src_lo) - _regalloc->reg2offset(second_src_lo);
2387   }
2388 
2389   // Comparison between reg -> stack and reg -> stack
2390   if (OptoReg::is_stack(first_dst_lo) && OptoReg::is_stack(second_dst_lo) &&
2391       OptoReg::is_reg(first_src_lo) && OptoReg::is_reg(second_src_lo)) {
2392     return _regalloc->reg2offset(first_dst_lo) - _regalloc->reg2offset(second_dst_lo);
2393   }
2394 
2395   return 0; // Not comparable
2396 }
2397 
2398 void Scheduling::AddNodeToAvailableList(Node *n) {
2399   assert( !n->is_Proj(), "projections never directly made available" );
2400 #ifndef PRODUCT
2401   if (_cfg->C->trace_opto_output()) {
2402     tty->print("#   AddNodeToAvailableList: ");
2403     n->dump();
2404   }
2405 #endif
2406 
2407   int latency = _current_latency[n->_idx];
2408 
2409   // Insert in latency order (insertion sort). If two MachSpillCopyNodes
2410   // for stack spilling or unspilling have the same latency, we sort
2411   // them in the order of stack offset. Some ports (e.g. aarch64) may also
2412   // have more opportunities to do ld/st merging
2413   uint i;
2414   for (i = 0; i < _available.size(); i++) {
2415     if (_current_latency[_available[i]->_idx] > latency) {
2416       break;
2417     } else if (_current_latency[_available[i]->_idx] == latency &&
2418                n->is_MachSpillCopy() && _available[i]->is_MachSpillCopy() &&
2419                compare_two_spill_nodes(n, _available[i]) > 0) {
2420       break;
2421     }
2422   }
2423 
2424   // Special Check for compares following branches
2425   if( n->is_Mach() && _scheduled.size() > 0 ) {
2426     int op = n->as_Mach()->ideal_Opcode();
2427     Node *last = _scheduled[0];
2428     if( last->is_MachIf() && last->in(1) == n &&
2429         ( op == Op_CmpI ||
2430           op == Op_CmpU ||
2431           op == Op_CmpUL ||
2432           op == Op_CmpP ||
2433           op == Op_CmpF ||
2434           op == Op_CmpD ||
2435           op == Op_CmpL ) ) {
2436 
2437       // Recalculate position, moving to front of same latency
2438       for ( i=0 ; i < _available.size(); i++ )
2439         if (_current_latency[_available[i]->_idx] >= latency)
2440           break;
2441     }
2442   }
2443 
2444   // Insert the node in the available list
2445   _available.insert(i, n);
2446 
2447 #ifndef PRODUCT
2448   if (_cfg->C->trace_opto_output())
2449     dump_available();
2450 #endif
2451 }
2452 
2453 void Scheduling::DecrementUseCounts(Node *n, const Block *bb) {
2454   for ( uint i=0; i < n->len(); i++ ) {
2455     Node *def = n->in(i);
2456     if (!def) continue;
2457     if( def->is_Proj() )        // If this is a machine projection, then
2458       def = def->in(0);         // propagate usage thru to the base instruction
2459 
2460     if(_cfg->get_block_for_node(def) != bb) { // Ignore if not block-local
2461       continue;
2462     }
2463 
2464     // Compute the latency
2465     uint l = _bundle_cycle_number + n->latency(i);
2466     if (_current_latency[def->_idx] < l)
2467       _current_latency[def->_idx] = l;
2468 
2469     // If this does not have uses then schedule it
2470     if ((--_uses[def->_idx]) == 0)
2471       AddNodeToAvailableList(def);
2472   }
2473 }
2474 
2475 void Scheduling::AddNodeToBundle(Node *n, const Block *bb) {
2476 #ifndef PRODUCT
2477   if (_cfg->C->trace_opto_output()) {
2478     tty->print("#   AddNodeToBundle: ");
2479     n->dump();
2480   }
2481 #endif
2482 
2483   // Remove this from the available list
2484   uint i;
2485   for (i = 0; i < _available.size(); i++)
2486     if (_available[i] == n)
2487       break;
2488   assert(i < _available.size(), "entry in _available list not found");
2489   _available.remove(i);
2490 
2491   // See if this fits in the current bundle
2492   const Pipeline *node_pipeline = n->pipeline();
2493   const Pipeline_Use& node_usage = node_pipeline->resourceUse();
2494 
2495   // Check for instructions to be placed in the delay slot. We
2496   // do this before we actually schedule the current instruction,
2497   // because the delay slot follows the current instruction.
2498   if (Pipeline::_branch_has_delay_slot &&
2499       node_pipeline->hasBranchDelay() &&
2500       !_unconditional_delay_slot) {
2501 
2502     uint siz = _available.size();
2503 
2504     // Conditional branches can support an instruction that
2505     // is unconditionally executed and not dependent by the
2506     // branch, OR a conditionally executed instruction if
2507     // the branch is taken.  In practice, this means that
2508     // the first instruction at the branch target is
2509     // copied to the delay slot, and the branch goes to
2510     // the instruction after that at the branch target
2511     if ( n->is_MachBranch() ) {
2512 
2513       assert( !n->is_MachNullCheck(), "should not look for delay slot for Null Check" );
2514       assert( !n->is_Catch(),         "should not look for delay slot for Catch" );
2515 
2516 #ifndef PRODUCT
2517       _branches++;
2518 #endif
2519 
2520       // At least 1 instruction is on the available list
2521       // that is not dependent on the branch
2522       for (uint i = 0; i < siz; i++) {
2523         Node *d = _available[i];
2524         const Pipeline *avail_pipeline = d->pipeline();
2525 
2526         // Don't allow safepoints in the branch shadow, that will
2527         // cause a number of difficulties
2528         if ( avail_pipeline->instructionCount() == 1 &&
2529              !avail_pipeline->hasMultipleBundles() &&
2530              !avail_pipeline->hasBranchDelay() &&
2531              Pipeline::instr_has_unit_size() &&
2532              d->size(_regalloc) == Pipeline::instr_unit_size() &&
2533              NodeFitsInBundle(d) &&
2534              !node_bundling(d)->used_in_delay()) {
2535 
2536           if (d->is_Mach() && !d->is_MachSafePoint()) {
2537             // A node that fits in the delay slot was found, so we need to
2538             // set the appropriate bits in the bundle pipeline information so
2539             // that it correctly indicates resource usage.  Later, when we
2540             // attempt to add this instruction to the bundle, we will skip
2541             // setting the resource usage.
2542             _unconditional_delay_slot = d;
2543             node_bundling(n)->set_use_unconditional_delay();
2544             node_bundling(d)->set_used_in_unconditional_delay();
2545             _bundle_use.add_usage(avail_pipeline->resourceUse());
2546             _current_latency[d->_idx] = _bundle_cycle_number;
2547             _next_node = d;
2548             ++_bundle_instr_count;
2549 #ifndef PRODUCT
2550             _unconditional_delays++;
2551 #endif
2552             break;
2553           }
2554         }
2555       }
2556     }
2557 
2558     // No delay slot, add a nop to the usage
2559     if (!_unconditional_delay_slot) {
2560       // See if adding an instruction in the delay slot will overflow
2561       // the bundle.
2562       if (!NodeFitsInBundle(_nop)) {
2563 #ifndef PRODUCT
2564         if (_cfg->C->trace_opto_output())
2565           tty->print("#  *** STEP(1 instruction for delay slot) ***\n");
2566 #endif
2567         step(1);
2568       }
2569 
2570       _bundle_use.add_usage(_nop->pipeline()->resourceUse());
2571       _next_node = _nop;
2572       ++_bundle_instr_count;
2573     }
2574 
2575     // See if the instruction in the delay slot requires a
2576     // step of the bundles
2577     if (!NodeFitsInBundle(n)) {
2578 #ifndef PRODUCT
2579       if (_cfg->C->trace_opto_output())
2580         tty->print("#  *** STEP(branch won't fit) ***\n");
2581 #endif
2582       // Update the state information
2583       _bundle_instr_count = 0;
2584       _bundle_cycle_number += 1;
2585       _bundle_use.step(1);
2586     }
2587   }
2588 
2589   // Get the number of instructions
2590   uint instruction_count = node_pipeline->instructionCount();
2591   if (node_pipeline->mayHaveNoCode() && n->size(_regalloc) == 0)
2592     instruction_count = 0;
2593 
2594   // Compute the latency information
2595   uint delay = 0;
2596 
2597   if (instruction_count > 0 || !node_pipeline->mayHaveNoCode()) {
2598     int relative_latency = _current_latency[n->_idx] - _bundle_cycle_number;
2599     if (relative_latency < 0)
2600       relative_latency = 0;
2601 
2602     delay = _bundle_use.full_latency(relative_latency, node_usage);
2603 
2604     // Does not fit in this bundle, start a new one
2605     if (delay > 0) {
2606       step(delay);
2607 
2608 #ifndef PRODUCT
2609       if (_cfg->C->trace_opto_output())
2610         tty->print("#  *** STEP(%d) ***\n", delay);
2611 #endif
2612     }
2613   }
2614 
2615   // If this was placed in the delay slot, ignore it
2616   if (n != _unconditional_delay_slot) {
2617 
2618     if (delay == 0) {
2619       if (node_pipeline->hasMultipleBundles()) {
2620 #ifndef PRODUCT
2621         if (_cfg->C->trace_opto_output())
2622           tty->print("#  *** STEP(multiple instructions) ***\n");
2623 #endif
2624         step(1);
2625       }
2626 
2627       else if (instruction_count + _bundle_instr_count > Pipeline::_max_instrs_per_cycle) {
2628 #ifndef PRODUCT
2629         if (_cfg->C->trace_opto_output())
2630           tty->print("#  *** STEP(%d >= %d instructions) ***\n",
2631                      instruction_count + _bundle_instr_count,
2632                      Pipeline::_max_instrs_per_cycle);
2633 #endif
2634         step(1);
2635       }
2636     }
2637 
2638     if (node_pipeline->hasBranchDelay() && !_unconditional_delay_slot)
2639       _bundle_instr_count++;
2640 
2641     // Set the node's latency
2642     _current_latency[n->_idx] = _bundle_cycle_number;
2643 
2644     // Now merge the functional unit information
2645     if (instruction_count > 0 || !node_pipeline->mayHaveNoCode())
2646       _bundle_use.add_usage(node_usage);
2647 
2648     // Increment the number of instructions in this bundle
2649     _bundle_instr_count += instruction_count;
2650 
2651     // Remember this node for later
2652     if (n->is_Mach())
2653       _next_node = n;
2654   }
2655 
2656   // It's possible to have a BoxLock in the graph and in the _bbs mapping but
2657   // not in the bb->_nodes array.  This happens for debug-info-only BoxLocks.
2658   // 'Schedule' them (basically ignore in the schedule) but do not insert them
2659   // into the block.  All other scheduled nodes get put in the schedule here.
2660   int op = n->Opcode();
2661   if( (op == Op_Node && n->req() == 0) || // anti-dependence node OR
2662       (op != Op_Node &&         // Not an unused antidepedence node and
2663        // not an unallocated boxlock
2664        (OptoReg::is_valid(_regalloc->get_reg_first(n)) || op != Op_BoxLock)) ) {
2665 
2666     // Push any trailing projections
2667     if( bb->get_node(bb->number_of_nodes()-1) != n ) {
2668       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
2669         Node *foi = n->fast_out(i);
2670         if( foi->is_Proj() )
2671           _scheduled.push(foi);
2672       }
2673     }
2674 
2675     // Put the instruction in the schedule list
2676     _scheduled.push(n);
2677   }
2678 
2679 #ifndef PRODUCT
2680   if (_cfg->C->trace_opto_output())
2681     dump_available();
2682 #endif
2683 
2684   // Walk all the definitions, decrementing use counts, and
2685   // if a definition has a 0 use count, place it in the available list.
2686   DecrementUseCounts(n,bb);
2687 }
2688 
2689 // This method sets the use count within a basic block.  We will ignore all
2690 // uses outside the current basic block.  As we are doing a backwards walk,
2691 // any node we reach that has a use count of 0 may be scheduled.  This also
2692 // avoids the problem of cyclic references from phi nodes, as long as phi
2693 // nodes are at the front of the basic block.  This method also initializes
2694 // the available list to the set of instructions that have no uses within this
2695 // basic block.
2696 void Scheduling::ComputeUseCount(const Block *bb) {
2697 #ifndef PRODUCT
2698   if (_cfg->C->trace_opto_output())
2699     tty->print("# -> ComputeUseCount\n");
2700 #endif
2701 
2702   // Clear the list of available and scheduled instructions, just in case
2703   _available.clear();
2704   _scheduled.clear();
2705 
2706   // No delay slot specified
2707   _unconditional_delay_slot = nullptr;
2708 
2709 #ifdef ASSERT
2710   for( uint i=0; i < bb->number_of_nodes(); i++ )
2711     assert( _uses[bb->get_node(i)->_idx] == 0, "_use array not clean" );
2712 #endif
2713 
2714   // Force the _uses count to never go to zero for unscheduable pieces
2715   // of the block
2716   for( uint k = 0; k < _bb_start; k++ )
2717     _uses[bb->get_node(k)->_idx] = 1;
2718   for( uint l = _bb_end; l < bb->number_of_nodes(); l++ )
2719     _uses[bb->get_node(l)->_idx] = 1;
2720 
2721   // Iterate backwards over the instructions in the block.  Don't count the
2722   // branch projections at end or the block header instructions.
2723   for( uint j = _bb_end-1; j >= _bb_start; j-- ) {
2724     Node *n = bb->get_node(j);
2725     if( n->is_Proj() ) continue; // Projections handled another way
2726 
2727     // Account for all uses
2728     for ( uint k = 0; k < n->len(); k++ ) {
2729       Node *inp = n->in(k);
2730       if (!inp) continue;
2731       assert(inp != n, "no cycles allowed" );
2732       if (_cfg->get_block_for_node(inp) == bb) { // Block-local use?
2733         if (inp->is_Proj()) { // Skip through Proj's
2734           inp = inp->in(0);
2735         }
2736         ++_uses[inp->_idx];     // Count 1 block-local use
2737       }
2738     }
2739 
2740     // If this instruction has a 0 use count, then it is available
2741     if (!_uses[n->_idx]) {
2742       _current_latency[n->_idx] = _bundle_cycle_number;
2743       AddNodeToAvailableList(n);
2744     }
2745 
2746 #ifndef PRODUCT
2747     if (_cfg->C->trace_opto_output()) {
2748       tty->print("#   uses: %3d: ", _uses[n->_idx]);
2749       n->dump();
2750     }
2751 #endif
2752   }
2753 
2754 #ifndef PRODUCT
2755   if (_cfg->C->trace_opto_output())
2756     tty->print("# <- ComputeUseCount\n");
2757 #endif
2758 }
2759 
2760 // This routine performs scheduling on each basic block in reverse order,
2761 // using instruction latencies and taking into account function unit
2762 // availability.
2763 void Scheduling::DoScheduling() {
2764 #ifndef PRODUCT
2765   if (_cfg->C->trace_opto_output())
2766     tty->print("# -> DoScheduling\n");
2767 #endif
2768 
2769   Block *succ_bb = nullptr;
2770   Block *bb;
2771   Compile* C = Compile::current();
2772 
2773   // Walk over all the basic blocks in reverse order
2774   for (int i = _cfg->number_of_blocks() - 1; i >= 0; succ_bb = bb, i--) {
2775     bb = _cfg->get_block(i);
2776 
2777 #ifndef PRODUCT
2778     if (_cfg->C->trace_opto_output()) {
2779       tty->print("#  Schedule BB#%03d (initial)\n", i);
2780       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2781         bb->get_node(j)->dump();
2782       }
2783     }
2784 #endif
2785 
2786     // On the head node, skip processing
2787     if (bb == _cfg->get_root_block()) {
2788       continue;
2789     }
2790 
2791     // Skip empty, connector blocks
2792     if (bb->is_connector())
2793       continue;
2794 
2795     // If the following block is not the sole successor of
2796     // this one, then reset the pipeline information
2797     if (bb->_num_succs != 1 || bb->non_connector_successor(0) != succ_bb) {
2798 #ifndef PRODUCT
2799       if (_cfg->C->trace_opto_output()) {
2800         tty->print("*** bundle start of next BB, node %d, for %d instructions\n",
2801                    _next_node->_idx, _bundle_instr_count);
2802       }
2803 #endif
2804       step_and_clear();
2805     }
2806 
2807     // Leave untouched the starting instruction, any Phis, a CreateEx node
2808     // or Top.  bb->get_node(_bb_start) is the first schedulable instruction.
2809     _bb_end = bb->number_of_nodes()-1;
2810     for( _bb_start=1; _bb_start <= _bb_end; _bb_start++ ) {
2811       Node *n = bb->get_node(_bb_start);
2812       // Things not matched, like Phinodes and ProjNodes don't get scheduled.
2813       // Also, MachIdealNodes do not get scheduled
2814       if( !n->is_Mach() ) continue;     // Skip non-machine nodes
2815       MachNode *mach = n->as_Mach();
2816       int iop = mach->ideal_Opcode();
2817       if( iop == Op_CreateEx ) continue; // CreateEx is pinned
2818       if( iop == Op_Con ) continue;      // Do not schedule Top
2819       if( iop == Op_Node &&     // Do not schedule PhiNodes, ProjNodes
2820           mach->pipeline() == MachNode::pipeline_class() &&
2821           !n->is_SpillCopy() && !n->is_MachMerge() )  // Breakpoints, Prolog, etc
2822         continue;
2823       break;                    // Funny loop structure to be sure...
2824     }
2825     // Compute last "interesting" instruction in block - last instruction we
2826     // might schedule.  _bb_end points just after last schedulable inst.  We
2827     // normally schedule conditional branches (despite them being forced last
2828     // in the block), because they have delay slots we can fill.  Calls all
2829     // have their delay slots filled in the template expansions, so we don't
2830     // bother scheduling them.
2831     Node *last = bb->get_node(_bb_end);
2832     // Ignore trailing NOPs.
2833     while (_bb_end > 0 && last->is_Mach() &&
2834            last->as_Mach()->ideal_Opcode() == Op_Con) {
2835       last = bb->get_node(--_bb_end);
2836     }
2837     assert(!last->is_Mach() || last->as_Mach()->ideal_Opcode() != Op_Con, "");
2838     if( last->is_Catch() ||
2839         (last->is_Mach() && last->as_Mach()->ideal_Opcode() == Op_Halt) ) {
2840       // There might be a prior call.  Skip it.
2841       while (_bb_start < _bb_end && bb->get_node(--_bb_end)->is_MachProj());
2842     } else if( last->is_MachNullCheck() ) {
2843       // Backup so the last null-checked memory instruction is
2844       // outside the schedulable range. Skip over the nullcheck,
2845       // projection, and the memory nodes.
2846       Node *mem = last->in(1);
2847       do {
2848         _bb_end--;
2849       } while (mem != bb->get_node(_bb_end));
2850     } else {
2851       // Set _bb_end to point after last schedulable inst.
2852       _bb_end++;
2853     }
2854 
2855     assert( _bb_start <= _bb_end, "inverted block ends" );
2856 
2857     // Compute the register antidependencies for the basic block
2858     ComputeRegisterAntidependencies(bb);
2859     if (C->failing())  return;  // too many D-U pinch points
2860 
2861     // Compute the usage within the block, and set the list of all nodes
2862     // in the block that have no uses within the block.
2863     ComputeUseCount(bb);
2864 
2865     // Schedule the remaining instructions in the block
2866     while ( _available.size() > 0 ) {
2867       Node *n = ChooseNodeToBundle();
2868       guarantee(n != nullptr, "no nodes available");
2869       AddNodeToBundle(n,bb);
2870     }
2871 
2872     assert( _scheduled.size() == _bb_end - _bb_start, "wrong number of instructions" );
2873 #ifdef ASSERT
2874     for( uint l = _bb_start; l < _bb_end; l++ ) {
2875       Node *n = bb->get_node(l);
2876       uint m;
2877       for( m = 0; m < _bb_end-_bb_start; m++ )
2878         if( _scheduled[m] == n )
2879           break;
2880       assert( m < _bb_end-_bb_start, "instruction missing in schedule" );
2881     }
2882 #endif
2883 
2884     // Now copy the instructions (in reverse order) back to the block
2885     for ( uint k = _bb_start; k < _bb_end; k++ )
2886       bb->map_node(_scheduled[_bb_end-k-1], k);
2887 
2888 #ifndef PRODUCT
2889     if (_cfg->C->trace_opto_output()) {
2890       tty->print("#  Schedule BB#%03d (final)\n", i);
2891       uint current = 0;
2892       for (uint j = 0; j < bb->number_of_nodes(); j++) {
2893         Node *n = bb->get_node(j);
2894         if( valid_bundle_info(n) ) {
2895           Bundle *bundle = node_bundling(n);
2896           if (bundle->instr_count() > 0 || bundle->flags() > 0) {
2897             tty->print("*** Bundle: ");
2898             bundle->dump();
2899           }
2900           n->dump();
2901         }
2902       }
2903     }
2904 #endif
2905 #ifdef ASSERT
2906     verify_good_schedule(bb,"after block local scheduling");
2907 #endif
2908   }
2909 
2910 #ifndef PRODUCT
2911   if (_cfg->C->trace_opto_output())
2912     tty->print("# <- DoScheduling\n");
2913 #endif
2914 
2915   // Record final node-bundling array location
2916   _regalloc->C->output()->set_node_bundling_base(_node_bundling_base);
2917 
2918 } // end DoScheduling
2919 
2920 // Verify that no live-range used in the block is killed in the block by a
2921 // wrong DEF.  This doesn't verify live-ranges that span blocks.
2922 
2923 // Check for edge existence.  Used to avoid adding redundant precedence edges.
2924 static bool edge_from_to( Node *from, Node *to ) {
2925   for( uint i=0; i<from->len(); i++ )
2926     if( from->in(i) == to )
2927       return true;
2928   return false;
2929 }
2930 
2931 #ifdef ASSERT
2932 void Scheduling::verify_do_def( Node *n, OptoReg::Name def, const char *msg ) {
2933   // Check for bad kills
2934   if( OptoReg::is_valid(def) ) { // Ignore stores & control flow
2935     Node *prior_use = _reg_node[def];
2936     if( prior_use && !edge_from_to(prior_use,n) ) {
2937       tty->print("%s = ",OptoReg::as_VMReg(def)->name());
2938       n->dump();
2939       tty->print_cr("...");
2940       prior_use->dump();
2941       assert(edge_from_to(prior_use,n), "%s", msg);
2942     }
2943     _reg_node.map(def,nullptr); // Kill live USEs
2944   }
2945 }
2946 
2947 void Scheduling::verify_good_schedule( Block *b, const char *msg ) {
2948 
2949   // Zap to something reasonable for the verify code
2950   _reg_node.clear();
2951 
2952   // Walk over the block backwards.  Check to make sure each DEF doesn't
2953   // kill a live value (other than the one it's supposed to).  Add each
2954   // USE to the live set.
2955   for( uint i = b->number_of_nodes()-1; i >= _bb_start; i-- ) {
2956     Node *n = b->get_node(i);
2957     int n_op = n->Opcode();
2958     if( n_op == Op_MachProj && n->ideal_reg() == MachProjNode::fat_proj ) {
2959       // Fat-proj kills a slew of registers
2960       RegMaskIterator rmi(n->out_RegMask());
2961       while (rmi.has_next()) {
2962         OptoReg::Name kill = rmi.next();
2963         verify_do_def(n, kill, msg);
2964       }
2965     } else if( n_op != Op_Node ) { // Avoid brand new antidependence nodes
2966       // Get DEF'd registers the normal way
2967       verify_do_def( n, _regalloc->get_reg_first(n), msg );
2968       verify_do_def( n, _regalloc->get_reg_second(n), msg );
2969     }
2970 
2971     // Now make all USEs live
2972     for( uint i=1; i<n->req(); i++ ) {
2973       Node *def = n->in(i);
2974       assert(def != nullptr, "input edge required");
2975       OptoReg::Name reg_lo = _regalloc->get_reg_first(def);
2976       OptoReg::Name reg_hi = _regalloc->get_reg_second(def);
2977       if( OptoReg::is_valid(reg_lo) ) {
2978         assert(!_reg_node[reg_lo] || edge_from_to(_reg_node[reg_lo],def), "%s", msg);
2979         _reg_node.map(reg_lo,n);
2980       }
2981       if( OptoReg::is_valid(reg_hi) ) {
2982         assert(!_reg_node[reg_hi] || edge_from_to(_reg_node[reg_hi],def), "%s", msg);
2983         _reg_node.map(reg_hi,n);
2984       }
2985     }
2986 
2987   }
2988 
2989   // Zap to something reasonable for the Antidependence code
2990   _reg_node.clear();
2991 }
2992 #endif
2993 
2994 // Conditionally add precedence edges.  Avoid putting edges on Projs.
2995 static void add_prec_edge_from_to( Node *from, Node *to ) {
2996   if( from->is_Proj() ) {       // Put precedence edge on Proj's input
2997     assert( from->req() == 1 && (from->len() == 1 || from->in(1) == nullptr), "no precedence edges on projections" );
2998     from = from->in(0);
2999   }
3000   if( from != to &&             // No cycles (for things like LD L0,[L0+4] )
3001       !edge_from_to( from, to ) ) // Avoid duplicate edge
3002     from->add_prec(to);
3003 }
3004 
3005 void Scheduling::anti_do_def( Block *b, Node *def, OptoReg::Name def_reg, int is_def ) {
3006   if( !OptoReg::is_valid(def_reg) ) // Ignore stores & control flow
3007     return;
3008 
3009   if (OptoReg::is_reg(def_reg)) {
3010     VMReg vmreg = OptoReg::as_VMReg(def_reg);
3011     if (vmreg->is_reg() && !vmreg->is_concrete() && !vmreg->prev()->is_concrete()) {
3012       // This is one of the high slots of a vector register.
3013       // ScheduleAndBundle already checked there are no live wide
3014       // vectors in this method so it can be safely ignored.
3015       return;
3016     }
3017   }
3018 
3019   Node *pinch = _reg_node[def_reg]; // Get pinch point
3020   if ((pinch == nullptr) || _cfg->get_block_for_node(pinch) != b || // No pinch-point yet?
3021       is_def ) {    // Check for a true def (not a kill)
3022     _reg_node.map(def_reg,def); // Record def/kill as the optimistic pinch-point
3023     return;
3024   }
3025 
3026   Node *kill = def;             // Rename 'def' to more descriptive 'kill'
3027   debug_only( def = (Node*)((intptr_t)0xdeadbeef); )
3028 
3029   // After some number of kills there _may_ be a later def
3030   Node *later_def = nullptr;
3031 
3032   Compile* C = Compile::current();
3033 
3034   // Finding a kill requires a real pinch-point.
3035   // Check for not already having a pinch-point.
3036   // Pinch points are Op_Node's.
3037   if( pinch->Opcode() != Op_Node ) { // Or later-def/kill as pinch-point?
3038     later_def = pinch;            // Must be def/kill as optimistic pinch-point
3039     if ( _pinch_free_list.size() > 0) {
3040       pinch = _pinch_free_list.pop();
3041     } else {
3042       pinch = new Node(1); // Pinch point to-be
3043     }
3044     if (pinch->_idx >= _regalloc->node_regs_max_index()) {
3045       DEBUG_ONLY( pinch->dump(); );
3046       assert(false, "too many D-U pinch points: %d >= %d", pinch->_idx, _regalloc->node_regs_max_index());
3047       _cfg->C->record_method_not_compilable("too many D-U pinch points");
3048       return;
3049     }
3050     _cfg->map_node_to_block(pinch, b);      // Pretend it's valid in this block (lazy init)
3051     _reg_node.map(def_reg,pinch); // Record pinch-point
3052     //regalloc()->set_bad(pinch->_idx); // Already initialized this way.
3053     if( later_def->outcnt() == 0 || later_def->ideal_reg() == MachProjNode::fat_proj ) { // Distinguish def from kill
3054       pinch->init_req(0, C->top());     // set not null for the next call
3055       add_prec_edge_from_to(later_def,pinch); // Add edge from kill to pinch
3056       later_def = nullptr;           // and no later def
3057     }
3058     pinch->set_req(0,later_def);  // Hook later def so we can find it
3059   } else {                        // Else have valid pinch point
3060     if( pinch->in(0) )            // If there is a later-def
3061       later_def = pinch->in(0);   // Get it
3062   }
3063 
3064   // Add output-dependence edge from later def to kill
3065   if( later_def )               // If there is some original def
3066     add_prec_edge_from_to(later_def,kill); // Add edge from def to kill
3067 
3068   // See if current kill is also a use, and so is forced to be the pinch-point.
3069   if( pinch->Opcode() == Op_Node ) {
3070     Node *uses = kill->is_Proj() ? kill->in(0) : kill;
3071     for( uint i=1; i<uses->req(); i++ ) {
3072       if( _regalloc->get_reg_first(uses->in(i)) == def_reg ||
3073           _regalloc->get_reg_second(uses->in(i)) == def_reg ) {
3074         // Yes, found a use/kill pinch-point
3075         pinch->set_req(0,nullptr);  //
3076         pinch->replace_by(kill); // Move anti-dep edges up
3077         pinch = kill;
3078         _reg_node.map(def_reg,pinch);
3079         return;
3080       }
3081     }
3082   }
3083 
3084   // Add edge from kill to pinch-point
3085   add_prec_edge_from_to(kill,pinch);
3086 }
3087 
3088 void Scheduling::anti_do_use( Block *b, Node *use, OptoReg::Name use_reg ) {
3089   if( !OptoReg::is_valid(use_reg) ) // Ignore stores & control flow
3090     return;
3091   Node *pinch = _reg_node[use_reg]; // Get pinch point
3092   // Check for no later def_reg/kill in block
3093   if ((pinch != nullptr) && _cfg->get_block_for_node(pinch) == b &&
3094       // Use has to be block-local as well
3095       _cfg->get_block_for_node(use) == b) {
3096     if( pinch->Opcode() == Op_Node && // Real pinch-point (not optimistic?)
3097         pinch->req() == 1 ) {   // pinch not yet in block?
3098       pinch->del_req(0);        // yank pointer to later-def, also set flag
3099       // Insert the pinch-point in the block just after the last use
3100       b->insert_node(pinch, b->find_node(use) + 1);
3101       _bb_end++;                // Increase size scheduled region in block
3102     }
3103 
3104     add_prec_edge_from_to(pinch,use);
3105   }
3106 }
3107 
3108 // We insert antidependences between the reads and following write of
3109 // allocated registers to prevent illegal code motion. Hopefully, the
3110 // number of added references should be fairly small, especially as we
3111 // are only adding references within the current basic block.
3112 void Scheduling::ComputeRegisterAntidependencies(Block *b) {
3113 
3114 #ifdef ASSERT
3115   verify_good_schedule(b,"before block local scheduling");
3116 #endif
3117 
3118   // A valid schedule, for each register independently, is an endless cycle
3119   // of: a def, then some uses (connected to the def by true dependencies),
3120   // then some kills (defs with no uses), finally the cycle repeats with a new
3121   // def.  The uses are allowed to float relative to each other, as are the
3122   // kills.  No use is allowed to slide past a kill (or def).  This requires
3123   // antidependencies between all uses of a single def and all kills that
3124   // follow, up to the next def.  More edges are redundant, because later defs
3125   // & kills are already serialized with true or antidependencies.  To keep
3126   // the edge count down, we add a 'pinch point' node if there's more than
3127   // one use or more than one kill/def.
3128 
3129   // We add dependencies in one bottom-up pass.
3130 
3131   // For each instruction we handle it's DEFs/KILLs, then it's USEs.
3132 
3133   // For each DEF/KILL, we check to see if there's a prior DEF/KILL for this
3134   // register.  If not, we record the DEF/KILL in _reg_node, the
3135   // register-to-def mapping.  If there is a prior DEF/KILL, we insert a
3136   // "pinch point", a new Node that's in the graph but not in the block.
3137   // We put edges from the prior and current DEF/KILLs to the pinch point.
3138   // We put the pinch point in _reg_node.  If there's already a pinch point
3139   // we merely add an edge from the current DEF/KILL to the pinch point.
3140 
3141   // After doing the DEF/KILLs, we handle USEs.  For each used register, we
3142   // put an edge from the pinch point to the USE.
3143 
3144   // To be expedient, the _reg_node array is pre-allocated for the whole
3145   // compilation.  _reg_node is lazily initialized; it either contains a null,
3146   // or a valid def/kill/pinch-point, or a leftover node from some prior
3147   // block.  Leftover node from some prior block is treated like a null (no
3148   // prior def, so no anti-dependence needed).  Valid def is distinguished by
3149   // it being in the current block.
3150   bool fat_proj_seen = false;
3151   uint last_safept = _bb_end-1;
3152   Node* end_node         = (_bb_end-1 >= _bb_start) ? b->get_node(last_safept) : nullptr;
3153   Node* last_safept_node = end_node;
3154   for( uint i = _bb_end-1; i >= _bb_start; i-- ) {
3155     Node *n = b->get_node(i);
3156     int is_def = n->outcnt();   // def if some uses prior to adding precedence edges
3157     if( n->is_MachProj() && n->ideal_reg() == MachProjNode::fat_proj ) {
3158       // Fat-proj kills a slew of registers
3159       // This can add edges to 'n' and obscure whether or not it was a def,
3160       // hence the is_def flag.
3161       fat_proj_seen = true;
3162       RegMaskIterator rmi(n->out_RegMask());
3163       while (rmi.has_next()) {
3164         OptoReg::Name kill = rmi.next();
3165         anti_do_def(b, n, kill, is_def);
3166       }
3167     } else {
3168       // Get DEF'd registers the normal way
3169       anti_do_def( b, n, _regalloc->get_reg_first(n), is_def );
3170       anti_do_def( b, n, _regalloc->get_reg_second(n), is_def );
3171     }
3172 
3173     // Kill projections on a branch should appear to occur on the
3174     // branch, not afterwards, so grab the masks from the projections
3175     // and process them.
3176     if (n->is_MachBranch() || (n->is_Mach() && n->as_Mach()->ideal_Opcode() == Op_Jump)) {
3177       for (DUIterator_Fast imax, i = n->fast_outs(imax); i < imax; i++) {
3178         Node* use = n->fast_out(i);
3179         if (use->is_Proj()) {
3180           RegMaskIterator rmi(use->out_RegMask());
3181           while (rmi.has_next()) {
3182             OptoReg::Name kill = rmi.next();
3183             anti_do_def(b, n, kill, false);
3184           }
3185         }
3186       }
3187     }
3188 
3189     // Check each register used by this instruction for a following DEF/KILL
3190     // that must occur afterward and requires an anti-dependence edge.
3191     for( uint j=0; j<n->req(); j++ ) {
3192       Node *def = n->in(j);
3193       if( def ) {
3194         assert( !def->is_MachProj() || def->ideal_reg() != MachProjNode::fat_proj, "" );
3195         anti_do_use( b, n, _regalloc->get_reg_first(def) );
3196         anti_do_use( b, n, _regalloc->get_reg_second(def) );
3197       }
3198     }
3199     // Do not allow defs of new derived values to float above GC
3200     // points unless the base is definitely available at the GC point.
3201 
3202     Node *m = b->get_node(i);
3203 
3204     // Add precedence edge from following safepoint to use of derived pointer
3205     if( last_safept_node != end_node &&
3206         m != last_safept_node) {
3207       for (uint k = 1; k < m->req(); k++) {
3208         const Type *t = m->in(k)->bottom_type();
3209         if( t->isa_oop_ptr() &&
3210             t->is_ptr()->offset() != 0 ) {
3211           last_safept_node->add_prec( m );
3212           break;
3213         }
3214       }
3215 
3216       // Do not allow a CheckCastPP node whose input is a raw pointer to
3217       // float past a safepoint.  This can occur when a buffered inline
3218       // type is allocated in a loop and the CheckCastPP from that
3219       // allocation is reused outside the loop.  If the use inside the
3220       // loop is scalarized the CheckCastPP will no longer be connected
3221       // to the loop safepoint.  See JDK-8264340.
3222       if (m->is_Mach() && m->as_Mach()->ideal_Opcode() == Op_CheckCastPP) {
3223         Node *def = m->in(1);
3224         if (def != nullptr && def->bottom_type()->base() == Type::RawPtr) {
3225           last_safept_node->add_prec(m);
3226         }
3227       }
3228     }
3229 
3230     if( n->jvms() ) {           // Precedence edge from derived to safept
3231       // Check if last_safept_node was moved by pinch-point insertion in anti_do_use()
3232       if( b->get_node(last_safept) != last_safept_node ) {
3233         last_safept = b->find_node(last_safept_node);
3234       }
3235       for( uint j=last_safept; j > i; j-- ) {
3236         Node *mach = b->get_node(j);
3237         if( mach->is_Mach() && mach->as_Mach()->ideal_Opcode() == Op_AddP )
3238           mach->add_prec( n );
3239       }
3240       last_safept = i;
3241       last_safept_node = m;
3242     }
3243   }
3244 
3245   if (fat_proj_seen) {
3246     // Garbage collect pinch nodes that were not consumed.
3247     // They are usually created by a fat kill MachProj for a call.
3248     garbage_collect_pinch_nodes();
3249   }
3250 }
3251 
3252 // Garbage collect pinch nodes for reuse by other blocks.
3253 //
3254 // The block scheduler's insertion of anti-dependence
3255 // edges creates many pinch nodes when the block contains
3256 // 2 or more Calls.  A pinch node is used to prevent a
3257 // combinatorial explosion of edges.  If a set of kills for a
3258 // register is anti-dependent on a set of uses (or defs), rather
3259 // than adding an edge in the graph between each pair of kill
3260 // and use (or def), a pinch is inserted between them:
3261 //
3262 //            use1   use2  use3
3263 //                \   |   /
3264 //                 \  |  /
3265 //                  pinch
3266 //                 /  |  \
3267 //                /   |   \
3268 //            kill1 kill2 kill3
3269 //
3270 // One pinch node is created per register killed when
3271 // the second call is encountered during a backwards pass
3272 // over the block.  Most of these pinch nodes are never
3273 // wired into the graph because the register is never
3274 // used or def'ed in the block.
3275 //
3276 void Scheduling::garbage_collect_pinch_nodes() {
3277 #ifndef PRODUCT
3278   if (_cfg->C->trace_opto_output()) tty->print("Reclaimed pinch nodes:");
3279 #endif
3280   int trace_cnt = 0;
3281   for (uint k = 0; k < _reg_node.max(); k++) {
3282     Node* pinch = _reg_node[k];
3283     if ((pinch != nullptr) && pinch->Opcode() == Op_Node &&
3284         // no predecence input edges
3285         (pinch->req() == pinch->len() || pinch->in(pinch->req()) == nullptr) ) {
3286       cleanup_pinch(pinch);
3287       _pinch_free_list.push(pinch);
3288       _reg_node.map(k, nullptr);
3289 #ifndef PRODUCT
3290       if (_cfg->C->trace_opto_output()) {
3291         trace_cnt++;
3292         if (trace_cnt > 40) {
3293           tty->print("\n");
3294           trace_cnt = 0;
3295         }
3296         tty->print(" %d", pinch->_idx);
3297       }
3298 #endif
3299     }
3300   }
3301 #ifndef PRODUCT
3302   if (_cfg->C->trace_opto_output()) tty->print("\n");
3303 #endif
3304 }
3305 
3306 // Clean up a pinch node for reuse.
3307 void Scheduling::cleanup_pinch( Node *pinch ) {
3308   assert (pinch && pinch->Opcode() == Op_Node && pinch->req() == 1, "just checking");
3309 
3310   for (DUIterator_Last imin, i = pinch->last_outs(imin); i >= imin; ) {
3311     Node* use = pinch->last_out(i);
3312     uint uses_found = 0;
3313     for (uint j = use->req(); j < use->len(); j++) {
3314       if (use->in(j) == pinch) {
3315         use->rm_prec(j);
3316         uses_found++;
3317       }
3318     }
3319     assert(uses_found > 0, "must be a precedence edge");
3320     i -= uses_found;    // we deleted 1 or more copies of this edge
3321   }
3322   // May have a later_def entry
3323   pinch->set_req(0, nullptr);
3324 }
3325 
3326 #ifndef PRODUCT
3327 
3328 void Scheduling::dump_available() const {
3329   tty->print("#Availist  ");
3330   for (uint i = 0; i < _available.size(); i++)
3331     tty->print(" N%d/l%d", _available[i]->_idx,_current_latency[_available[i]->_idx]);
3332   tty->cr();
3333 }
3334 
3335 // Print Scheduling Statistics
3336 void Scheduling::print_statistics() {
3337   // Print the size added by nops for bundling
3338   tty->print("Nops added %d bytes to total of %d bytes",
3339              _total_nop_size, _total_method_size);
3340   if (_total_method_size > 0)
3341     tty->print(", for %.2f%%",
3342                ((double)_total_nop_size) / ((double) _total_method_size) * 100.0);
3343   tty->print("\n");
3344 
3345   // Print the number of branch shadows filled
3346   if (Pipeline::_branch_has_delay_slot) {
3347     tty->print("Of %d branches, %d had unconditional delay slots filled",
3348                _total_branches, _total_unconditional_delays);
3349     if (_total_branches > 0)
3350       tty->print(", for %.2f%%",
3351                  ((double)_total_unconditional_delays) / ((double)_total_branches) * 100.0);
3352     tty->print("\n");
3353   }
3354 
3355   uint total_instructions = 0, total_bundles = 0;
3356 
3357   for (uint i = 1; i <= Pipeline::_max_instrs_per_cycle; i++) {
3358     uint bundle_count   = _total_instructions_per_bundle[i];
3359     total_instructions += bundle_count * i;
3360     total_bundles      += bundle_count;
3361   }
3362 
3363   if (total_bundles > 0)
3364     tty->print("Average ILP (excluding nops) is %.2f\n",
3365                ((double)total_instructions) / ((double)total_bundles));
3366 }
3367 #endif
3368 
3369 //-----------------------init_scratch_buffer_blob------------------------------
3370 // Construct a temporary BufferBlob and cache it for this compile.
3371 void PhaseOutput::init_scratch_buffer_blob(int const_size) {
3372   // If there is already a scratch buffer blob allocated and the
3373   // constant section is big enough, use it.  Otherwise free the
3374   // current and allocate a new one.
3375   BufferBlob* blob = scratch_buffer_blob();
3376   if ((blob != nullptr) && (const_size <= _scratch_const_size)) {
3377     // Use the current blob.
3378   } else {
3379     if (blob != nullptr) {
3380       BufferBlob::free(blob);
3381     }
3382 
3383     ResourceMark rm;
3384     _scratch_const_size = const_size;
3385     int size = C2Compiler::initial_code_buffer_size(const_size);
3386     if (C->has_scalarized_args()) {
3387       // Inline type entry points (MachVEPNodes) require lots of space for GC barriers and oop verification
3388       // when loading object fields from the buffered argument. Increase scratch buffer size accordingly.
3389       ciMethod* method = C->method();
3390       int barrier_size = UseZGC ? 200 : (7 DEBUG_ONLY(+ 37));
3391       int arg_num = 0;
3392       if (!method->is_static()) {
3393         if (method->is_scalarized_arg(arg_num)) {
3394           size += method->holder()->as_inline_klass()->oop_count() * barrier_size;
3395         }
3396         arg_num++;
3397       }
3398       for (ciSignatureStream str(method->signature()); !str.at_return_type(); str.next()) {
3399         if (method->is_scalarized_arg(arg_num)) {
3400           size += str.type()->as_inline_klass()->oop_count() * barrier_size;
3401         }
3402         arg_num++;
3403       }
3404     }
3405     blob = BufferBlob::create("Compile::scratch_buffer", size);
3406     // Record the buffer blob for next time.
3407     set_scratch_buffer_blob(blob);
3408     // Have we run out of code space?
3409     if (scratch_buffer_blob() == nullptr) {
3410       // Let CompilerBroker disable further compilations.
3411       C->record_failure("Not enough space for scratch buffer in CodeCache");
3412       return;
3413     }
3414   }
3415 
3416   // Initialize the relocation buffers
3417   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
3418   set_scratch_locs_memory(locs_buf);
3419 }
3420 
3421 
3422 //-----------------------scratch_emit_size-------------------------------------
3423 // Helper function that computes size by emitting code
3424 uint PhaseOutput::scratch_emit_size(const Node* n) {
3425   // Start scratch_emit_size section.
3426   set_in_scratch_emit_size(true);
3427 
3428   // Emit into a trash buffer and count bytes emitted.
3429   // This is a pretty expensive way to compute a size,
3430   // but it works well enough if seldom used.
3431   // All common fixed-size instructions are given a size
3432   // method by the AD file.
3433   // Note that the scratch buffer blob and locs memory are
3434   // allocated at the beginning of the compile task, and
3435   // may be shared by several calls to scratch_emit_size.
3436   // The allocation of the scratch buffer blob is particularly
3437   // expensive, since it has to grab the code cache lock.
3438   BufferBlob* blob = this->scratch_buffer_blob();
3439   assert(blob != nullptr, "Initialize BufferBlob at start");
3440   assert(blob->size() > MAX_inst_size, "sanity");
3441   relocInfo* locs_buf = scratch_locs_memory();
3442   address blob_begin = blob->content_begin();
3443   address blob_end   = (address)locs_buf;
3444   assert(blob->contains(blob_end), "sanity");
3445   CodeBuffer buf(blob_begin, blob_end - blob_begin);
3446   buf.initialize_consts_size(_scratch_const_size);
3447   buf.initialize_stubs_size(MAX_stubs_size);
3448   assert(locs_buf != nullptr, "sanity");
3449   int lsize = MAX_locs_size / 3;
3450   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
3451   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
3452   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
3453   // Mark as scratch buffer.
3454   buf.consts()->set_scratch_emit();
3455   buf.insts()->set_scratch_emit();
3456   buf.stubs()->set_scratch_emit();
3457 
3458   // Do the emission.
3459 
3460   Label fakeL; // Fake label for branch instructions.
3461   Label*   saveL = nullptr;
3462   uint save_bnum = 0;
3463   bool is_branch = n->is_MachBranch();
3464   C2_MacroAssembler masm(&buf);
3465   masm.bind(fakeL);
3466   if (is_branch) {
3467     n->as_MachBranch()->save_label(&saveL, &save_bnum);
3468     n->as_MachBranch()->label_set(&fakeL, 0);
3469   }
3470   n->emit(&masm, C->regalloc());
3471 
3472   // Emitting into the scratch buffer should not fail
3473   assert(!C->failing_internal() || C->failure_is_artificial(), "Must not have pending failure. Reason is: %s", C->failure_reason());
3474 
3475   // Restore label.
3476   if (is_branch) {
3477     n->as_MachBranch()->label_set(saveL, save_bnum);
3478   }
3479 
3480   // End scratch_emit_size section.
3481   set_in_scratch_emit_size(false);
3482 
3483   return buf.insts_size();
3484 }
3485 
3486 void PhaseOutput::install() {
3487   if (!C->should_install_code()) {
3488     return;
3489   } else if (C->stub_function() != nullptr) {
3490     install_stub(C->stub_name());
3491   } else {
3492     install_code(C->method(),
3493                  C->entry_bci(),
3494                  CompileBroker::compiler2(),
3495                  C->has_unsafe_access(),
3496                  SharedRuntime::is_wide_vector(C->max_vector_size()));
3497   }
3498 }
3499 
3500 void PhaseOutput::install_code(ciMethod*         target,
3501                                int               entry_bci,
3502                                AbstractCompiler* compiler,
3503                                bool              has_unsafe_access,
3504                                bool              has_wide_vectors) {
3505   // Check if we want to skip execution of all compiled code.
3506   {
3507 #ifndef PRODUCT
3508     if (OptoNoExecute) {
3509       C->record_method_not_compilable("+OptoNoExecute");  // Flag as failed
3510       return;
3511     }
3512 #endif
3513     Compile::TracePhase tp("install_code", &timers[_t_registerMethod]);
3514 
3515     if (C->is_osr_compilation()) {
3516       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
3517       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
3518     } else {
3519       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
3520       if (_code_offsets.value(CodeOffsets::Verified_Inline_Entry) == -1) {
3521         _code_offsets.set_value(CodeOffsets::Verified_Inline_Entry, _first_block_size);
3522       }
3523       if (_code_offsets.value(CodeOffsets::Verified_Inline_Entry_RO) == -1) {
3524         _code_offsets.set_value(CodeOffsets::Verified_Inline_Entry_RO, _first_block_size);
3525       }
3526       if (_code_offsets.value(CodeOffsets::Entry) == -1) {
3527         _code_offsets.set_value(CodeOffsets::Entry, _first_block_size);
3528       }
3529       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
3530     }
3531 
3532     C->env()->register_method(target,
3533                               entry_bci,
3534                               &_code_offsets,
3535                               _orig_pc_slot_offset_in_bytes,
3536                               code_buffer(),
3537                               frame_size_in_words(),
3538                               _oop_map_set,
3539                               &_handler_table,
3540                               inc_table(),
3541                               compiler,
3542                               has_unsafe_access,
3543                               SharedRuntime::is_wide_vector(C->max_vector_size()),
3544                               C->has_monitors(),
3545                               C->has_scoped_access(),
3546                               0);
3547 
3548     if (C->log() != nullptr) { // Print code cache state into compiler log
3549       C->log()->code_cache_state();
3550     }
3551   }
3552 }
3553 void PhaseOutput::install_stub(const char* stub_name) {
3554   // Entry point will be accessed using stub_entry_point();
3555   if (code_buffer() == nullptr) {
3556     Matcher::soft_match_failure();
3557   } else {
3558     if (PrintAssembly && (WizardMode || Verbose))
3559       tty->print_cr("### Stub::%s", stub_name);
3560 
3561     if (!C->failing()) {
3562       assert(C->fixed_slots() == 0, "no fixed slots used for runtime stubs");
3563 
3564       // Make the NMethod
3565       // For now we mark the frame as never safe for profile stackwalking
3566       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
3567                                                       code_buffer(),
3568                                                       CodeOffsets::frame_never_safe,
3569                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),
3570                                                       frame_size_in_words(),
3571                                                       oop_map_set(),
3572                                                       false);
3573       assert(rs != nullptr && rs->is_runtime_stub(), "sanity check");
3574 
3575       C->set_stub_entry_point(rs->entry_point());
3576     }
3577   }
3578 }
3579 
3580 // Support for bundling info
3581 Bundle* PhaseOutput::node_bundling(const Node *n) {
3582   assert(valid_bundle_info(n), "oob");
3583   return &_node_bundling_base[n->_idx];
3584 }
3585 
3586 bool PhaseOutput::valid_bundle_info(const Node *n) {
3587   return (_node_bundling_limit > n->_idx);
3588 }
3589 
3590 //------------------------------frame_size_in_words-----------------------------
3591 // frame_slots in units of words
3592 int PhaseOutput::frame_size_in_words() const {
3593   // shift is 0 in LP32 and 1 in LP64
3594   const int shift = (LogBytesPerWord - LogBytesPerInt);
3595   int words = _frame_slots >> shift;
3596   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
3597   return words;
3598 }
3599 
3600 // To bang the stack of this compiled method we use the stack size
3601 // that the interpreter would need in case of a deoptimization. This
3602 // removes the need to bang the stack in the deoptimization blob which
3603 // in turn simplifies stack overflow handling.
3604 int PhaseOutput::bang_size_in_bytes() const {
3605   return MAX2(frame_size_in_bytes() + os::extra_bang_size_in_bytes(), C->interpreter_frame_size());
3606 }
3607 
3608 //------------------------------dump_asm---------------------------------------
3609 // Dump formatted assembly
3610 #if defined(SUPPORT_OPTO_ASSEMBLY)
3611 void PhaseOutput::dump_asm_on(outputStream* st, int* pcs, uint pc_limit) {
3612 
3613   int pc_digits = 3; // #chars required for pc
3614   int sb_chars  = 3; // #chars for "start bundle" indicator
3615   int tab_size  = 8;
3616   if (pcs != nullptr) {
3617     int max_pc = 0;
3618     for (uint i = 0; i < pc_limit; i++) {
3619       max_pc = (max_pc < pcs[i]) ? pcs[i] : max_pc;
3620     }
3621     pc_digits  = ((max_pc < 4096) ? 3 : ((max_pc < 65536) ? 4 : ((max_pc < 65536*256) ? 6 : 8))); // #chars required for pc
3622   }
3623   int prefix_len = ((pc_digits + sb_chars + tab_size - 1)/tab_size)*tab_size;
3624 
3625   bool cut_short = false;
3626   st->print_cr("#");
3627   st->print("#  ");  C->tf()->dump_on(st);  st->cr();
3628   st->print_cr("#");
3629 
3630   // For all blocks
3631   int pc = 0x0;                 // Program counter
3632   char starts_bundle = ' ';
3633   C->regalloc()->dump_frame();
3634 
3635   Node *n = nullptr;
3636   for (uint i = 0; i < C->cfg()->number_of_blocks(); i++) {
3637     if (VMThread::should_terminate()) {
3638       cut_short = true;
3639       break;
3640     }
3641     Block* block = C->cfg()->get_block(i);
3642     if (block->is_connector() && !Verbose) {
3643       continue;
3644     }
3645     n = block->head();
3646     if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3647       pc = pcs[n->_idx];
3648       st->print("%*.*x", pc_digits, pc_digits, pc);
3649     }
3650     st->fill_to(prefix_len);
3651     block->dump_head(C->cfg(), st);
3652     if (block->is_connector()) {
3653       st->fill_to(prefix_len);
3654       st->print_cr("# Empty connector block");
3655     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
3656       st->fill_to(prefix_len);
3657       st->print_cr("# Block is sole successor of call");
3658     }
3659 
3660     // For all instructions
3661     Node *delay = nullptr;
3662     for (uint j = 0; j < block->number_of_nodes(); j++) {
3663       if (VMThread::should_terminate()) {
3664         cut_short = true;
3665         break;
3666       }
3667       n = block->get_node(j);
3668       if (valid_bundle_info(n)) {
3669         Bundle* bundle = node_bundling(n);
3670         if (bundle->used_in_unconditional_delay()) {
3671           delay = n;
3672           continue;
3673         }
3674         if (bundle->starts_bundle()) {
3675           starts_bundle = '+';
3676         }
3677       }
3678 
3679       if (WizardMode) {
3680         n->dump();
3681       }
3682 
3683       if( !n->is_Region() &&    // Dont print in the Assembly
3684           !n->is_Phi() &&       // a few noisely useless nodes
3685           !n->is_Proj() &&
3686           !n->is_MachTemp() &&
3687           !n->is_SafePointScalarObject() &&
3688           !n->is_Catch() &&     // Would be nice to print exception table targets
3689           !n->is_MergeMem() &&  // Not very interesting
3690           !n->is_top() &&       // Debug info table constants
3691           !(n->is_Con() && !n->is_Mach())// Debug info table constants
3692           ) {
3693         if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3694           pc = pcs[n->_idx];
3695           st->print("%*.*x", pc_digits, pc_digits, pc);
3696         } else {
3697           st->fill_to(pc_digits);
3698         }
3699         st->print(" %c ", starts_bundle);
3700         starts_bundle = ' ';
3701         st->fill_to(prefix_len);
3702         n->format(C->regalloc(), st);
3703         st->cr();
3704       }
3705 
3706       // If we have an instruction with a delay slot, and have seen a delay,
3707       // then back up and print it
3708       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
3709         // Coverity finding - Explicit null dereferenced.
3710         guarantee(delay != nullptr, "no unconditional delay instruction");
3711         if (WizardMode) delay->dump();
3712 
3713         if (node_bundling(delay)->starts_bundle())
3714           starts_bundle = '+';
3715         if ((pcs != nullptr) && (n->_idx < pc_limit)) {
3716           pc = pcs[n->_idx];
3717           st->print("%*.*x", pc_digits, pc_digits, pc);
3718         } else {
3719           st->fill_to(pc_digits);
3720         }
3721         st->print(" %c ", starts_bundle);
3722         starts_bundle = ' ';
3723         st->fill_to(prefix_len);
3724         delay->format(C->regalloc(), st);
3725         st->cr();
3726         delay = nullptr;
3727       }
3728 
3729       // Dump the exception table as well
3730       if( n->is_Catch() && (Verbose || WizardMode) ) {
3731         // Print the exception table for this offset
3732         _handler_table.print_subtable_for(pc);
3733       }
3734       st->bol(); // Make sure we start on a new line
3735     }
3736     st->cr(); // one empty line between blocks
3737     assert(cut_short || delay == nullptr, "no unconditional delay branch");
3738   } // End of per-block dump
3739 
3740   if (cut_short)  st->print_cr("*** disassembly is cut short ***");
3741 }
3742 #endif
3743 
3744 #ifndef PRODUCT
3745 void PhaseOutput::print_statistics() {
3746   Scheduling::print_statistics();
3747 }
3748 #endif